A453/R-94-035a
      EPA
               United States
               Environmental Protection
               Agency
               Office of Air Quality
               Planning and Standards
               Research Triangle Park NC 27711
               Air
EPA-453/R-94-0368
May 1994
National Emission Standards
for Hazardous Air Pollutants
for Source Categories: Aerospace
Manufacturing and Rework--
Background Information
for Proposed Standards
    Draft
     EIS

-------
                         EPA-453/R-94-036a
National Emission Standards for Hazardous Air
 Pollutants for Source Categories:  Aerospace
  Manufacturing and Rework -- Background
     Information for Proposed Standards
         Emission Standards Division
    U.S. Environmental Protection Agency
         Office of Air and Radiation
 Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
                May 1994

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                        ENVIRONMENTAL PROTECTION AGENCY

                  Hazardous Air Pollutants from the Aerospace
                     Manufacturing and Rework  Industry  --
                 Background Information for Proposed Standards
                                  Prepared by:
-Bruce C. Jordan/7                                                (Date)  '
Director, Emis^ron Standards Division
U.S. Environmental Protection Agency
Research Triangle Park, NC  27711

1.    The proposed standards regulate emissions of hazardous air  pollutants
      from cleaning operations; primer, topcoat, and chemical milling maskant
      application operations; depainting operations; and handling and storage
      of waste at aerospace manufacturing and rework facilities.   Only those
      operations that are part of major sources under Section 112(d) of  the
      Clean Air Act as amended in 1990 will be regulated.

2.    Copies of this document have been sent to following  Federal  Departments:
      Labor, Health and Human Services, Defense, Transportation,  Agriculture,
      Commerce, Interior, and Energy; the National Science Foundation; and the
      Council on Environmental Quality.  Copies have also  been sent to members
      of the State and Territorial Air Pollution Program Administrators; the
      Association of Local Air Pollution Control Officials; EPA Regional
      Administrators; and other interested parties.

3.    For additional information contact:

      Ms. Vickie Boothe
      Standards Development Branch (MD-13)
      U.S. Environmental Protection Agency
      Research Triangle Park, NC  27711
      Telephone:  (919) 541-0164

4.    Paper copies of this document may be obtained from:

      National Technical Information Service (NTIS)
      5285 Port Royal Road
      Springfield, VA  22161
      Telephone:  (703) 487-4650

5.    Electronic copies of this document may be obtained from the EPA
      Technology Transfer Network (TTN).  The TTN is an electronic bulletin
      board system which is free, except for the normal long distance charges.
     •To access the aerospace BID:

      •     Set software to data bits:  8, N; stop bits:   1
            Use access number (919) 541-5742 for 1200, 2400, or 9600 bps
            modems [access problems should be directed to  the system operator
            at (919) 541-5384].
      •     Specify TTN Bulleting Board:  Clean Air Act Amendments
      •     Select menu item:  Recently Signed Rules

-------
                                 (DISCLAIMER)


This report has been reviewed by the Emission Standards Division of the Office
of Air Quality Planning and Standards, EPA, and approved for publication.
Mention of trade names or commercial products is not intended to constitute
endorsement or recommendation for use.  Copies of this report are available
through the Library Services Office (MD-35), U.S. Environmental Protection
Agency, Research Triangle Park, N.C. 277111, or from National Technical
Information Service, 5285 Port Royal Road, Springfield, Virginia 22161.

-------
                        ENVIRONMENTAL  PROTECTION AGENCY

                  Hazardous  Air Pollutants  from the  Aerospace
                     Manufacturing and Rework Industry --
                 Background  Information  for Proposed Standards

                                 Prepared by:



                                                                 11/9 V
      C. Jordan /                                               (Date)  '
Director, Emis£*on Standards Division
U.S. Environmental Protection Agency
Research Triangle Park, NC  27711

1.    The proposed standards regulate emissions of hazardous air pollutants
      from cleaning operations; primer, topcoat, and chemical milling maskant
      application operations; depainting operations; and handling and storage
      of waste at aerospace manufacturing and rework facilities.  Only those
      operations that are part of major sources under Section 112(d) of the
      Clean Air Act as amended in 1990 will be regulated.

2.    Copies of this document have been sent to following Federal Departments:
      Labor, Health and Human Services, Defense, Transportation, Agriculture,
      Commerce, Interior, and Energy; the National Science Foundation; and the
      Council on Environmental Quality.  Copies have also been sent to members
      of the State and Territorial Air Pollution Program Administrators; the
      Association of Local Air Pollution Control Officials; EPA Regional
      Administrators; and other interested parties.

3.    For additional information contact:

      Ms. Vickie Boothe
      Standards Development Branch (MD-13)
      U.S. Environmental Protection Agency
      Research Triangle Park, NC  27711
      Telephone:  (919) 541-0164

4.    Paper copies of this document may be obtained from:

      National Technical Information Service (NTIS)
      5285 Port Royal Road
      Springfield, VA  22161
      Telephone:  (703) 487-4650

5.    Electronic copies of this document may be obtained from the EPA
      Technology Transfer Network (TTN).  The TTN is an electronic bulletin
      board system which is free, except for the normal long distance charges.
      To access the aerospace BID:

      •     Set software to data bits:  8, N; stop bits:  1
      •     Use access number (919) 541-5742 for 1200, 2400, or 9600 bps
            modems [access problems should be directed to the system operator
            at (919) 541-5384].
      *     Specify TTN Bulleting Board:  Clean Air Act Amendments
      •     Select menu item:  Recently Signed Rules

-------
                                 (DISCLAIMER)


This report has been reviewed by the Emission Standards Division of the Office
of Air Quality Planning and Standards, EPA, and approved for publication.
Mention of trade names or commercial products is not intended to constitute
endorsement or recommendation for use.  Copies of this report are available
through the Library Services Office (MD-35), U.S. Environmental Protection
Agency, Research Triangle Park, N.C. 277111, or from National Technical
Information Service, 5285 Port Royal Road, Springfield, Virginia 22161.

-------
                               TABLE OF CONTENTS

Chapter                                                                 Page

List of Figures  	    vi

Li st of Tab! es  	    vi i

1.    Summary  	    1-1
      1.1  Proposed Standards for Affected Sources  	    1-2
            1.1.1  Cleaning Operation  	    1-3
            1.1.2  Primer and Topcoat Application Operations  	    1-6
                  1.1.2.1  Organic HAP and VOC Emissions  	    1-6
                  1.1.2.2  Inorganic HAP Emissions  	    1-9
            1.1.3  Depainting Operation  	    1-10
                  1.1.3.1  Organic HAP Emissions	    1-11
                  1.1.3.2  Inorganic HAP Emissions  	    1-12
            1.1.4  Chemical Milling Maskant Operation   	    1-12
            1.1.5  Handling and Storage of Waste  	    1-14
      1.2  Environmental Impact  	    1-14
            1.2.1  Estimated Air Emission Reductions  	    1-14
                  1.2.1.1  Existing Facilities  	    1-14
                  1.2.1.2  New Facilities   	    1-14
            1.2.2  Estimated Secondary Environmental Impacts  	    1-14
            1.2.3  Estimated Energy Impacts  	    1-16
      1.3  Economic Impacts (Estimated Cost Impacts)  	    1-18
            1.3.1  Existing Facilities  	    1-18
                  1.3.1.1  Capital Costs  	    1-18
                  1.3.1.2  Annual Costs  	    1-19
            1.3.2  New Facilities  	    1-21

2.    Regulatory Authority  	    2-1
      2.1  Background and Authority for Standards   	    2-1
      2.2  Selection of Pollutants and Source Categories  	    2-6
      2.3  Procedure for Development of NESHAP  	    2-7
      2.4  Consideration of Costs  	    2-9
      2.5  Consideration of Environmental Impacts   	    2-11
      2.6  Residual Risk Standards	    2-12

3,    Aerospace Manufacturing and Rework Operations   	    3-1
      3.1   General  	    3-1
      3.2   Process Description  	    3-5
            3.2.1  Materials Receiving  	    3-5
            3.2.2  Machining and Mechanical Processing  	    3-6
                  3.2.2.1  Machining  	    3-6
                  3.2.2.2  Deburring  	    3-6
                  3.2.2.3  Forming  	    3-7
                  3.2.2.4  Welding  	    3-7
            3.2.3  Maskant Application and Chemical Milling   	    3-7
                  3.2.3.1  Maskant Application  	    3-7
                  3,2.3,2  Chemical Milling  .......................    3-8
            3.2.4  Heat Treating  	,.    3-9

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                        TABLE OF CONTENTS (continued)


Chapter                       (                                         Page

            3.2.5  Sealing  	     3-9
            3.2.6  Adhesive Bonding  	     3-10
            3.2.7  Cleaning  	     3-10
                  3.2.7.1   Hand-Wipe and Flush Cleaning  	     3-10
                  3.2.7.2   Spray Gun and Coating Line Cleaning  	     3-11
            3.2.8  Metal  Finishing  	     3-11
                  3.2.8.1   Conversion Coating  	     3-12
                  3.2.8.2   Anodizing  	     3-12
                  3.2.8.3   Passivation  	     3-13
                  3.2.8.4   Pickling  	     3-13
                  3.2.8.5   Alkaline Cleaning  	     3-13
                  3.2.8.6   Deoxidizing,  Desmutting,  and Descaling  .     3-13
                  3.2.8.7   Polishing	     3-13
                  3.2.8.8   Abrasive Cleaning  	     3-14
                  3.2.8.9   Mechanical Surface Preparation  	     3-14
            3.2.9  Coating Application  	     3-14
            3.2.10  Coating Removal (Depainting )  	     3-15
            3.2.11  Electrodeposition (Metal Plating)   	     3-15
            3.2.12  Composites Processing   	     3-16
                  3.2.12.1  Injection Molding  	     3-17
                  3.2.12.2  Compression  Molding  	     3-17
                  3.2.12.3  Lay-up  	     3-17
                  3.2.12.4  Debulking  	     3-17
                  3.2.12.5  Curing  	  '  3-17
                  3.2.12.6  Break-Out  	     3-18
            3.2.13  Testing  	     3-18
      3.3   Uncontrolled Emissions  	     3-18
            3.3.1  Maskant Application  	     3-19
            3.3.2  Cleaning  	     3-21
            3.3.3  Coating Application  	     3-21
            3.3.4  Coating Removal (Depainting)  	     3-22
      3.4   Existing State Regulations  	     3-22
            3.4.1  California  	     3-23
                  3.4.1.1      SIP Approved Aerospace Coating Rule
                              Requirements  	     3-25
                  3.4.1.2      South Coast Air Quality Management
                              District  	     3-25
                  3.4.1.3      San Diego  County Air Pollution Control
                              District  	     3-30
                  3.4.1.4     Bay Area Air Quality Management
                              District	     3-32
                  3.4.1.5     Ventura County Air Pollution Control
                              District  	     3-34
                  3.4.1.6     Imperial County Air Pollution Control
                              District  	     3-38
            3.4.2  Alabama  	     3-38
            3.4.3  Connecticut  	     3-40
            3.4.4  Oklahoma  	     3-40
            3.4.5  Texas  	     3-41

                                      ii

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                         TABLE OF CONTENTS  (continued)


Chapter                                                                 Page

            3.4.6  Missouri  	    3-42
            3.4.7  Washington  	    3-42
            3.4.8  New York  	    3-43
            3.4.9  Other States  	    3-44
            3.4.10  Air Toxic Rules for Various States  	    3-45
                  3.4.10.1  Michigan	    3-45
                  3.4.10.2  Ohio  	    3-46
                  3.4.10.3  Connecticut  	    3-47
                  3.4.10.4  Kansas  	    3-48
                  3.4.10.5  Washington  	    3-49
      3.5  References	    3-51

4.  Emission Capture and Control Techniques  	    4-1
      4.1  Preventive Measures  	    4-2
            4.1.1 Product Reformulation  	    4-2
                  4.1.1.1  Coating Reformulations  	    4-2
                        4.1.1.1.1  Waterborne Coatings  	    4-2
                        4.1.1.1.2  Higher Solids Coatings  	    4-3
                        4.1.1.1.3  Powder Coatings  	    4-4
                        4.1.1.1.4  Self-Priming Topcoats  	    4-5
                        4.1.1.1.5  Resin Seal Anodizing  	    4-5
                  4.1.1.2  Hand-wipe Cleaner Reformulations   	    4-6
                        4.1.1.2.1  Aqueous Cleaners  	    4-6
                        4.1.1.2.2  Citrus-Based Cleaners  	    4-6
                        4.1.1.2.3  Reduced HAP Content Cleaners  ...    4-7
                        4.1.1.2.4  Non-chemical Cleaners  	    4-7
                  4.1.1.3  Depainting Stripper Reformulations  	    4-7
            4.1.2  Equipment Changes  	    4-7
                  4.1.2.1  High Transfer Efficiency Spray Guns  	    4-8
                        4.1.2.1.1  Conventional Airspray  	    4-8
                        4.1.2.1.2  Airless Spraying	    4-8
                        4.1.2.1.3  Conventional High Transfer
                                   Efficiency Application Methods ..    4-9
                                    4.1.2.1.3.1  Dip Coating  	    4-9
                                    4.1.2.1.3.2  Roll Coating  	    4-9
                                    4.1.2.1.3.3  Brush Coating  	    4-9
                                    4.1.2.1.3.4  Flow Coating  	    4-9
                        4.1.2.1.4  High Volume Low Pressure (HVLP)  .    4-10
                        4.1.2.1.5  Electrostatic Spraying	    4-11
                  4.1.2.2  Enclosed Spray Gun Cleaners  	    4-13
                  4.1.2.3  Proportional Paint Mixers  	    4-13
                  4.1.2.4  Non-chemical Depainting Processes  	    4-14
                        4.1.2.4.1  Plastic Media Blasting (PMB)	    4-14
                        4.1.2.4.2  Sodium Bicarbonate Blasting  	    4-15
                        4.1.2.4.3  Carbon Dioxide Blasting Process  ,    4-16
                        4.1.2.4.4  Ice Crystal Blasting	    4-16
                        4.1.2.4.5  Wheat Starch Blasting  	    4-17
                        4.1.2.4.6  Water Jet Strinninn  	    4-17
                        4.1.2.4.7  High Pressure Water Jet  	    4-18

                                      iii

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                         TABLE OF CONTENTS  (continued)


Chanter                                                                  Page

                        4.1.2.4.8  Exclmer Lasers  	     4-18
                        4.1.2.4.9  Xenon Flash Lamp  	     4-18
                        4.1.2.4.10  Carbon Dioxide Pulsed Laser   ...     4-19
            4.1.3  Work Practice Standards  	     4-19
      4.2  Control Devices  	     4-20
            4.2.1  Carbon Adsorbers  	.-	     4-21
            4.2.2  Incinerators  	     4-24
                  4.2.2.1  Thermal  Incinerators   	     4-24
                  4.2.2.2  Catalytic Incinerators  	     4-26
            4.2.3  Ultraviolet Oxidation (UVOX)   	     4-28
            4.2.4  Activated Carbon Fiber Adsorbent  	     4-28
            4.2.5  Catalyst-coated Filter Media   	     4-30
            4.2.6  Baghouses  	     4-30
            4.2.7  Mechanical Centrifugal Separator (Rotoclone)   ...     4-30
            4.2.8  Dry Filters for Spray Booths   	     4-32
            4.2.9  Waterwash Spray Booths  	     4-34
      4.7   References   	     4-35

5.  Modification and Reconstruction  	     5-1
      5.1  Provisions for Modification and Reconstruction  	     5-2
            5.1.1  Modification  	     5-2
            5.1.2  Reconstruction  	     5-3
      5.2   Application to Aerospace Manufacturing
            and Rework Facilities  	     5-4
            5.2.1  Spray Booths  	     5-4
            5.2.2  Addition of a New Operation  	     5-5
            5.2.3  Addition of a New Product Line  	     5-5

6.  Model Plants  	     6-1
      6.1  Model Plants  	     6-1
            6.1.1  Primary Model Plant Parameters  	     6-10
                  6.1.1.1  Market Segment   	     6-10
                  6.1.1.2  Work Type  	     6-10
                  6.1.1.3  Size  	     6-11
            6.1.2  Secondary Model Plant Parameters  	     6-11
                  6.1.2.1  Process Profile  	     6-14

7.  Nationwide Baseline HAP Emissions and Environmental  Impacts   ...     7-1
      7.1  Introduction  	     7-1
      7.2  Nationwide Baseline HAP Emissions   	     7-1
      7.3  Environmental Impacts   	     7-1

8.  Cost Impacts  	     8-1
      8.1  Introduction  	     8-1
      8.2  Annual Costs  	     3-1
      8.3  Capital Costs   	     8-2

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                         TABLE OF  CONTENTS  (continued)


Chapter                                                                  Page

9.  Economic Impacts   	     9-1
      9.1  Industry Profile   	     9-1
            9.1.1  Introduction   	     9-1
            9.1.2  Industry Overview  	     9-3
            9.1.3  Original Equipment Manufacture   	     9-9
                  9.1.3.1  Market Structure   	     9-9
                  9.1.3.2  Production  	     9-16
                  9.1.3.3  Employment  	     9-24
                  9.1.3.4  Demand/Consumption	     9-28
                  9.1.3.5  Profitability   	     9-33
                  9.1.3.6  Foreign Trade and  International
                           Competitiveness   	     9-35
            9.1.4  Outlook  	     9-38
            9.1.5  Rework in  the  Aerospace Industry 	     9-39
                  9.1.5.1  Overview  	     9-39
                  9.1.5.2  Large  Commercial Transport Aircraft   	     9-40
                         9.1.5.2.1  The Demand  Side   	     9-40
                         9.1.5.2.2 Capacity and the Supply Side   ...     9-46
                  9.1.5.3  General Aviation Aircraft 	     9-49
                  9.1.5.4  Military Aircraft,  Guided Missiles,
                           and Space Vehicles   	     9-49
            9.1.6  Coatings Manufacturing  	     9-53
                  9.1.6.1  Aerospace Coatings	     9-55
                  9.1.6.2  Future Prospects  for Coating
                           Manufacturers	     9-55
      9.2  Economic  Impact Analysis (EIA)  	     9-57
            9.2.1  Introduction   	     9-57
            9.2.2  Analytical  Framework  	     9-57
                  9.2.2.1  Primary Impacts   	     9-59
                  9.2.2.2  Secondary Impacts   	     9-62
            9.2.3  Discussion of  Economic  Impacts   	     9-64
            9.2.4  Small Business Impacts  	     9-76
            9.2.5  Summary and Conclusions   	     9-77
      9.3  References	     9-80

APPENDIX A. Development  of Environmental Impacts
            for  Model  Plants	     A-l

APPENDIX B.  Development of Model Plant Costs	     B-l

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                               LIST OF FIGURES
                                                                        Page
Figure 3-1  Active U.S.  Aerospace Manufacturing Base  	    3-4
Figure 4-1  Typical Two-bed Regenerative Carbon Adsorption
            System  	    4-22
Figure 4-2  Schematic Diagram of a Thermal Incinerator  	    4-25
Figure 4-3  Schematic Diagram of a Catalytic Incinerator System  ...    4-27
Figure 4-4  UVOX, Packed Tower,  and Adsorber System  	    4-29
Figure 4-5  Typical Cloth Filters  	    4-31
Figure 4-6  Typical Mechanical Centrifugal Separator  	    4-33
Figure 6-1  Distribution of Aerospace Facilities
            by Number of Employees  	    6-12
Figure 6-2  Distribution of Aerospace Manufacturing Facilities
            by Number of Employees  	    6-13
Figure 9-1  Aerospace Industry  	    9-4
Figure 9-2  The Relationship Between RGDP and
            Aerospace Production  	    9-21
Figure 9-3  Production Growth Rates  	    9-23
Figure 9-4  Production Workers by SIC  	    9-27
Figure 9-5  Value Added by Labor  	    9-29
Figure 9-6  Relative Impact of Several Factors
            on Heavy Airframe Maintenance in 1990  	    9-42
Figure 9-7  Age Profile of U.S.  Transport Fleet
            in the Year 2000 (as of March 1990)  	    9-43
Figure 9-8  Direction of Demand and Supply in the
            Aerospace Industry and of Impacts of NESHAP
            Proposed for the Aerospace Coatings Industry  	    9-60
Figure 9-9  Effects of Proposed NESHAP on Producers of
            Final Goods in the Aerospace  Industry  	    9-51
Figure 9-10 Effects of Proposed NESHAP on Factor Markets  	    9-65
                                      VI

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                                LIST OF TABLES
Table 1-1   Composition Requirements for Approved
                                                                         Page

Table
Table

Table

Table
Table

Table

Table
Table

Table

Table
Table
Table
Table
Table
Table
Table

Table

Table

3-1
3-2

3-3

3-4
3-5

3-6

3-7
3-8

3-9

3-10
3-11
3-12
3-13
3-14
3-15
4-1

6-1

6-2
Cleaning Solvents 	
Aerospace Manufacturing SIC Codes 	
Total Annual HAP Emissions by Process as Reported
in the Section 114 and Site Visit Questionnaires 	
Miscellaneous Metal Parts and Products CTG
VOC Limits 	
VOC Content Requirements (grams/liter) in SIP Rules ...
South Coast Air Quality Management District
VOC Limits 	 	 	
San Diego County Air Pollution Control District
VOC Limits 	
Bay Area Air Quality Management District VOC Limits ...
Ventura County Air Quality Management District
ROC Limits 	 	
Imperial County Air Pollution Control District
VOC Limits 	
Oklahoma MMP&P VOC Limits 	 	 	 	 	
Texas MMP&P VOC Limits 	
Missouri VOC Limits 	 	 	
Washington Aerospace Coating VOC Limits 	 „ 	
New York VOC Limits 	 	 	
Areas that Apply the MMP&P CTG Limits 	 	
Percent Reduction in Emissions with High Transfer
Efficiency Equipment from Section 114 Data 	 . ., 	
Aerospace Manufacturing and Rework Facilities that
Received Section 114 Questionnaires 	 	 	 	
Aerospace Manufacturing and Rework Facilities that
1-4
3-2

3-20

3-24
3-26

3-27

3-31
3-33

3-35

3-39
3-41
3-42
3-42
3-43
3-44
3-44

4-12

6-2

            Received Section  114 Questionnaires on Waste,
                        and  Inorganic Emissions   	
fi.fi
                                      Vll

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                          LIST OF TABLES (continued)
                                                                         Page
Table 6-3   Site Visit Facilities  	     6-8
Table 6-4   Model Plant Descriptions  	     6-9
Table 6-5   Model Plant Process Profiles  	     6-15
Table 7-1   Nationwide Baseline HAP Emissions  	     7-4
Table 7-2A  Organic HAP Emission Reductions  	     7-5
Table 7-2B  Inorganic HAP Emission Reductions  	     7-5
Table 7-2C  Total HAP Emission Reductions  	     7-5
Table 7-3   Wastewater Generation  	     7-6
Table 7-4A  Energy Consumption for Controlling Organic
            HAP Emissions  	     7-7
Table 7-4B  Energy Consumption for Controlling Inorganic
            HAP Emissions  	     7-7
Table 7-4C  Total Energy Consumption  	     7-7
Table 7-5A  Solid Waste Generation while Controlling
            Organic HAP Emissions  	     7-8
Table 7-5B  Solid Waste Generation while Controlling
            Inorganic HAP Emissions  	     7-9
Table 7-5C  Total Solid Waste Generation  	     7-9
Table 8-1   Control Costs for Commercial OEM  	     8-4
Table 8-2   Control Costs for Commercial Rework  	     8-5
Table 8-3   Control Costs for Military OEM  	     8-6
Table 8-4   Control Costs for Military Rework  	     8-7
Table 8-5   Summary of Control Costs	     8-8
Table 9-1   Products and Selected Manufacturers in the
            U.S. Aerospace Industry  	     9-6
Table 9-2   Distribution of Establishments in the U.S.
            Aerospace Industry by Employment Size, 1987   	     9-10
                                     vm

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                          LIST OF TABLES (continued)
Table 9-3   Distribution of Revenue Generated in the U.S.
            Aerospace Industry by Employment Size Class of
            Establishments in Each SIC, 1987  	    9-12
Table 9-4   Federal Outlays on Defense, NASA, and
            Aerospace Products and Services	    9-15
Table 9-5   Shipments of Complete U.S. Aircraft 1978-1992  	   9-17
Table 9-6   Orders, Shipments, Backlog, and Inventories
            of Aircraft, Missiles, Space Vehicles,
            and Parts,  1978 to 1990  	    9-19
Table 9-7   Total Shipments in the U.S. Aerospace
            Industry, 1984-1992  	    9-22
Table 9-8   Capacity Utilization Rates, U.S. Aerospace
            Industry, 1989, 1990  	    9-25
Table 9-9   Employment in the Aerospace Industry	    9-26
Table 9-10  Apparent Consumption of Aerospace Products,
            1987-1990  	    9-31
Table 9-11  Percent Value Added by Imports to Intermediate
            Products and Complete Units of the U.S. Aerospace
            Industry, 1989-1991  	    9-32
Table 9-12  Net Profit After Taxes, U.S. Aerospace
            Industry, 1976-1991	    9-34
Table 9-13A U.S. Exports of Aerospace Vehicles and
            Equipment, 1988-1991	    9-36
Table 9-13B U.S. Imports of Aerospace Vehicles and
            Equipment, 1988-1991  	    9-37
Table 9-14  Federal Aviation Regulation Part 145
            Rework Facilities, Number of Employees and
            Revenue by Employment-size Class, 1992  	    9-50
Table 9-15  Air Force Organic Depot Maintenance Facilities  	    9-52
Table 9-16  Value of Shipments for Paints and Coatings and
            Adhesives and Sealants 1987-1991  	    9-54
Table 9-17  Employment of Shipments for Paints and Coatings and
            Adhesives and Sealants 1987-1991	    9-56
                                      ix

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                          LIST OF TABLES (continued)
                                                                        Pace
Table 9-18  Per-plant Control Costs for Regulated
            Emission Sources  	    9-63
Table 9-19  Baseline and MACT Use of Strippers for
            Aircraft Depainting	    9-67
Table 9-20  Baseline and MACT Use of Chemical Milling Maskants  	    9-69
Table 9-21  Baseline and MACT Use of Solvents for
            Spray Gun Cleaning  	    9-71
Table 9-22  Baseline and MACT Use of Solvents for
            Hand Wipe Cleaning  	    9-72
Table 9-23A Annual Baseline and MACT Usage of Primers in
            Commercial and Military Facilities  	    9-74
Table 9-23B Annual Baseline and MACT Usage of Topcoats in
            Commercial and Military Facilities  	    9-75

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                              1.0  SUMMARY

      The proposed rule would limit organic HAP emissions from the
following sources at aerospace facilities:  cleaning operations,  primer
application operations, topcoat application operations, depainting
operations, chemical milling maskant application operations,  and  the
handling and storage of waste.  The proposed rule would also limit
inorganic HAP emissions from primer, topcoat, and depainting operations.
      Organic HAP emissions from chemical  milling maskant, primer, and
topcoat application operations occur from the evaporation of the  solvent
contained in the coatings.  These emissions occur during the application
of the coatings on aerospace vehicles or parts, which may take place in
large open areas, such as hangars, or partially or fully enclosed
spaces, such as within spray booths.
      Organic HAP emissions from cleaning and depainting operations
occur from evaporation of the volatile portion of the cleaning solvents
or chemical strippers.  Cleaning emissions are nearly always fugitive in
nature and occur at essentially every processing step.  Emissions from
depainting are typically fugitive in nature since the operation is
carried out within a large hangar or in open tanks.
      Organic HAP emissions from waste occur from evaporation of  the
volatile portion of the waste while it is being handled or stored.
These emissions are fugitive in nature, occurring from each waste
   I UU I I 1C. I
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      Inorganic HAP emissions from primer and topcoat application
operations occur during the application of the primer or topcoat.  These
inorganic HAP emissions are paint particulates, commonly referred to as
"overspray," that do not adhere to the surface being coated.  Like the
organic HAP emissions from the operations, the emission of the inorganic
HAPs occur in large open areas, such as hangars, or in partially or
fully enclosed spaces, such as within spray booths.
      Inorganic HAP emissions from depainting operations occur from most
non-chemical methods, such as plastic media blasting, used to strip an
aerospace vehicle.  (Chemical stripping techniques do not release
inorganic HAPs.)  These emissions occur as particulates generated during
the blasting process.  The operation is typically carried out within a
large hangar equipped with a ventilation system and particulate
filtration device (e.g., a baghouse).  The inorganic HAPs that are
released from the depainting operations are primarily found in the paint
being stripped, although some stripping media may contain trace amounts
of inorganic HAPs.
1.1  PROPOSED STANDARDS FOR AFFECTED SOURCES
      The affected sources for the proposed standards are defined as
follows:  (1) the cleaning operation, which includes all hand-wipe,
spray gun, and flush cleaning at the facility; (2) the primer
application operation, which includes all primer applications at the
facility; (3) the topcoat application operation, which includes all
topcoat applications at the facility; (4) the depainting operation,
which includes all depainting of the outer surface of aerospace vehicles
at the facility;  (5) the chemical milling maskant application operation,
which includes all chemical milling maskant applications at the facility
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for use in Type II chemical milling solutions; and (6) handling and
storage of waste.  The following paragraphs summarize the proposed
standards for each affected source.
1.1.1  Cleaning Operation
      The proposed standards for the hand-wipe, spray gun, and flush
cleaning operations would apply to all new and existing affected
sources.  The proposed standards would require that all fresh and used
cleaning solvents be stored in closed containers and solvent-laden
cloth, paper, or other material be placed in bags or other closed
containers immediately after use.  The bags or containers would be
required to be of such design so as to contain the vapors of the
cleaning solvent.  In addition, the proposed standards would require the
owner or operator to implement handling and transfer procedures to
minimize spills during filling and transferring the cleaning solvent to
or from enclosed systems, vats, waste containers, and other cleaning
operation equipment that hold or store fresh or used cleaning solvents.
The above requirements are known collectively as housekeeping measures.
      The proposed standard for the hand-wipe cleaning operation would
require the use of a cleaning solvent that conforms to the approved
composition list detailed in Table 1-1 or a cleaning solvent that has a
vapor pressure less than or equal to 45 millimeters of mercury (mm Hg)
at 20°C.
      The EPA is proposing a work practice standard for the cleaning of
spray guns at all new and existing affected sources.  The proposed rule
would require all spray guns to be cleaned by one or more of the
following methods:  (1) use of an enclosed spray gun cleaning system
that is kept closed when not in use; (2) unatomized discharge of solvent
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                              TABLE 1-1

       COMPOSITION REQUIREMENTS FOR APPROVED CLEANING SOLVENTS
  Cleaning Solvent Type
                   Definition
Aqueous
Cleaning solvents in which water is the primary
ingredient (>80 percent of solvent as applied
must be water).  Aqueous solvents must be non-
flammable, non-combustible, and 100 percent
soluble in water.  Detergents, surfactants, and
bioenzyme mixtures and nutrients may be combined
with the water along with a variety of additives
such as organic solvents (e.g., high boiling
point alcohols), builders, saponifiers,
inhibitors, emulsifiers, pH buffers, and
antifoaming agents.	
Hydrocarbon-Based
Cleaners that are composed of a mixture of
hydrocarbons and oxygenated hydrocarbons -and
have a maximum vapor pressure of 7 mm Hg at
20°C.  These cleaners also contain no HAPs or
ozone depleting compounds. .	
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into a waste container that is kept closed when not in use; (3)
disassembly of the spray gun and cleaning in a vat that is kept closed
when not in use; and (4) atomized spray into a waste container that is
fitted with a device designed to capture atomized solvent emissions.  In
addition, the EPA is proposing that leaks from enclosed spray gun
cleaners be repaired within 14 days from when the leak is first
discovered.  The EPA is also proposing a work practice standard for the
flush cleaning of parts, assemblies, and coating unit components.  Under
the proposed rule, each time a part, assembly, or coating unit component
(with the exception of spray guns) is flush cleaned, the used cleaning
solvent would be emptied into an enclosed container or collection system
that is kept closed when not in use.
      The following cleaning operations, which would still be required
to comply with the proposed housekeeping requirements, would be exempt
from the proposed cleaning solvent composition and vapor pressure
requirements:
      1.    Cleaning during manufacturing, assembly, installation, or
            testing of components of breathing oxygen systems that are
            exposed to the breathing oxygen;
      2.    Cleaning during manufacturing, assembly, installation, or
            testing of parts, subassemblies, or assemblies that are
            exposed to strong oxidizers or reducers (e.g., nitrogen
            tetroxide, liquid oxygen, hydrazine);
      3.    Cleaning and surface activation prior to adhesive bonding;
      4.    Cleaning of electronics and assemblies containing
            electronics;
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      5.     Cleaning of aircraft fluid systems  that  are exposed to the
            fluid.   Aircraft fluid systems  are  defined as those systems
            that handle hydraulic fluids, fuel,  cooling fluids, and
            oils;
      6.     Cleaning of fuel cells, fuel  tanks,  and  limited access
            spaces;
      7.     Surface  cleaning of solar cells,  coated  optics, and thermal
            control  surfaces;
      8.     Cleaning during fabrication,  assembly,  installation, and
            maintenance of upholstery, curtains, carpet, and other
            textile  materials used on the interior  of the aircraft;
      9.     Cleaning of metallic and non-metallic materials used in
            honeycomb cores during the manufacture  of these cores, and
            cleaning of the completed cores used in  the manufacture of
            aerospace vehicles or components;
      10.   Cleaning of polycarbonate substrates; and
      11.   Cleaning and solvent usage associated with production,
            research, development, quality  control,  or laboratory
            testing.
1.1.2  Primer and Topcoat Application Operations
      The proposed standards for primer and topcoat  application
operations would be  the same for all new and existing affected sources.
Standards are being  proposed to limit organic and inorganic HAP
emissions from these operations.
      1.1.2.1  Organic HAP and VOC emissions.  The  standards being
proposed would limit the organic HAP emissions  from primer application
operations to an equivalent organic HAP content level of 2.9 pounds of
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organic HAPs per gallon [350 grams per liter (g/1)] of primer (less
water) as applied and from topcoat application operations to an
equivalent organic HAP content level of 3.5 pounds of organic HAPs per
gallon (420 g/1) of topcoat (less water) as applied.  In addition to the
organic HAP limits, the proposed standards would limit VOC emissions
from primer application operations to an equivalent VOC content level of
2.9 pounds of VOCs per gallon of primer (less water and exempt solvents)
as applied and from topcoat application operations to an equivalent VOC
content level of 3.5 pounds of VOC per gallon of topcoat (less water and
exempt solvents) as applied.  Equivalent organic HAP and VOC content
level means the emissions that would be generated by the use of coatings
that are all equal to the applicable organic HAP or VOC content limits.
Exempt solvents are those organic compounds that have been determined by
the EPA to have negligible photochemical reactivity.
      Sources would be allowed to comply with the proposed organic HAP
and VOC content standards by the following means:  (1) use coatings that
individually comply with the organic HAP and VOC levels; (2) use any
combination of coatings such that the daily volume-weighted average
organic HAP and VOC contents of these coatings comply with the organic
HAP and VOC levels for that category (averaging of primers and topcoats
together is prohibited); (3) use a control device to reduce organic HAP
and VOC emissions such that the overall emissions from each affected
source are equivalent to or less than the emissions that would be
achieved by using compliant coatings at the proposed content levels; or
(4) any combination of the above.
      Compliance with the proposed standard must be shown on a monthly
basis when using al"! compliant coatings, or on a daily basis when using

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a weighted average or a control device other than a carbon adsorber.
When a carbon adsorber is used to comply with the proposed organic HAP
and VOC content limits, compliance must be shown by performing a solvent
mass balance for each rolling material balance period.  The length of
the rolling period will vary from source to source and is determined by
the procedure specified in proposed Method 310 in the proposed rule.
The minimum rolling period is one day, and the maximum rolling period is
30 days.
      Each control device used for the control of organic HAP or VOC
emissions from primer or topcoat application operations must have an
overall control efficiency, taking into account capture and removal
efficiency, of greater than or equal to 81 percent.  Except for
incidental emissions that may escape from the capture system, a control
device cannot be used to control only a portion of emissions from a
coating operation.
      In addition to the organic HAP and VOC content levels, the EPA is
proposing an equipment standard for the application of primers and
topcoats.  The proposed standards would require the use of flow coat,
roll coat, brush coat, dip coat, electrostatic attraction, or high
volume low pressure (HVLP) spray guns other than for the exemptions
listed below.  All application equipment would be required to be
operated and maintained according to manufacturer's specifications at
all times.
      The EPA is proposing to allow other application equipment that is
demonstrated to achieve emission levels equivalent to HVLP or
electrostatic spray guns.  Two methods are being proposed to demonstrate
this equivalence.  The first method involves comparing tha emissions
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generated by the alternative application method to the emissions
generated by HVLP or electrostatic application methods in actual
production.  In this case, the alternative method must generate
emissions less than or equal to that generated by HVLP or electrostatic
spray methods.  The second method, proposed as Method 309 in the
proposed rule, involves determining the transfer efficiency of the
alternative method and HVLP or electrostatic spray methods.  In this
case, the alternative application method must achieve a transfer
efficiency greater than or equal to HVLP or electrostatic application
methods.
      The EPA is proposing to exempt the following list of situations
and operations from the proposed equipment standard for the application
of primers and topcoats:
      1.    Any situation that normally requires the use of an extension
            on the spray gun to properly reach limited access spaces;
      2.    The application of coatings that contain fillers that
            adversely affect atomization with HVLP spray guns and cannot
            be applied by any of the specified application techniques;
      3.    The application of coatings that normally have a dried film
            thickness of less than 0.0005 inch and cannot be applied by
            any of the specified application techniques;
      4.    The use of airbrush application methods for stenciling,
            lettering, and other identification markings; and
      5.    Touchup and repair operations.
      1.1.2.2  Inorganic HAP emissions.  The standards being proposed
for inorganic HAP emissions from primer and topcoat application
operations would apply to those operations that spray apply coatings
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that contain inorganic HAPs (usually chromium, cadmium,  and selenium).
Such operations would be required to be performed in a booth or hangar
in which the airflow is directed across the part or assembly being
coated and exhausted through one or more outlets.  This  air stream would
be required to pass through either dry particulate filters or a
waterwash system to remove the particulates before exhausting to the
atmosphere.  In addition, the pressure drop across the filter or
waterwash would have to be maintained within the limits  specified by the
manufacturer.  If the pressure drop moves outside of these limits, then
the operation must immediately be shut down and corrective action taken.
The process cannot resume until the pressure drop is within the limits
specified by the manufacturer.
      The EPA is proposing to exempt the following list  of operations
from the proposed standards for inorganic HAP emissions  from primer and
topcoat application operations:
      1.  Touch-up of scratched surfaces or damaged paint;
      2.  Hole daubing for fasteners;
      3.  Touch-up of trimmed edges;
      4.  Coating prior to joining dissimilar metal components;
      5.  Stencil operations performed by brush or air brush;
      6.  Section joining; and
      7.  Touch-up of bushings and other similar components.
1.1.3  Depaintinq Operation
      Standards are being proposed for both organic HAP  emissions and
inorganic HAP emissions from depainting.  With the exception of the
proposed standard for spot stripping and decal removal,  as discussed
below, the standards being proposed for depainting would be the same for
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all new and existing affected sources.  The proposed standards would
apply only to the depainting of the outer surface of entire aerospace
vehicles, including the fuselage, wings, and horizontal and vertical
stabilizers of the aircraft, or the outer casing and stabilizers of
missiles and rockets.  Standards for the depainting of parts,
subassemblies, radomes, and parts normally removed from the completed
vehicle before depainting are not being proposed at this time.  However,
wings and stabilizers would always be required to comply.
      1.1.3.1  Organic HAP emissions.  The proposed standard would
require that there be no organic HAP emissions from the depainting
operation.  This standard could be achieved through the use of (1)
chemical strippers that contain no organic HAPs or (2) media blasting
equipment, high intensity ultra-violet light blasting, or any other non-
chemical depainting technique.  However, the proposed rule would allow
the use of organic HAP-containing chemical stripper for spot stripping
and decal removal.  The proposed rule would limit this use of organic
HAP-containing chemical stripper to an average of 26 gallons per
aircraft for commercial aircraft and 50 gallons per aircraft for
military aircraft, calculated on an annual basis.
      Non-chemical based depainting equipment would be required to be
operated and maintained according to manufacturer's specifications.
During any period of malfunction, the owner or operator would be allowed
to use a substitute material to depaint the vehicles.  Unless the
substitute material does not contain any organic HAPs, the substitute
material would not be allowed to be used for more than 14 consecutive
days.
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      1.1.3.2  Inorganic HAP emissions.  The proposed rule for inorganic
HAP emissions would apply to those depainting methods (typically
blasting methods) that generate airborne particulate emissions, such as
dust and paint particles, that contain inorganic HAPs.  The proposed
standard would require that the depainting operation be carried out in
an enclosed hangar and that any air stream removed from the depainting
area be directed through a particulate filter (e.g., panel-type filter
or baghouse) before exhausting to the atmosphere.  This filtration
system must have a removal efficiency greater than or equal to 99
percent, and the pressure drop across the filter must be maintained
within the limits specified by the manufacturer.  If the pressure drop
moves outside of these limits, then the operation must immediately be
shut down and corrective action taken.  The process cannot resume until
the pressure drop is within the limits specified by the manufacturer.
1.1.4  Chemical Milling Maskant Operation
      The proposed standard for the chemical milling maskant operation
would be the same for all new and existing affected sources and applies
only to those operations utilizing a Type II chemical milling solution.
The proposed standard would limit organic HAP emissions to an equivalent
organic HAP content level of 1.3 pounds organic HAP per gallon of
chemical milling maskant (less water) as applied, and limit the VOC
emissions to an equivalent VOC content level of 1.3 pounds VOC per
gallon of chemical milling maskant (less water and exempt solvents) as
applied.  Equivalent organic HAP and VOC content level means the
emissions that would be generated by the use of chemical milling
maskants that are all equal to the applicable organic HAP or VOC content
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limits.  Exempt solvents are those organic compounds that have been
determined by the EPA to have negligible photochemical reactivity.
      Compliance with this standard could be met by the following means:
(1) use only chemical milling maskants that individually comply with the
organic HAP and VOC content levels; (2) use any combination of chemical
milling maskants such that the daily volume-weighted average organic HAP
and VOC content levels of these chemical milling maskants used in the
chemical milling maskant operation complies with the organic HAP and VOC
content levels; (3) reduce organic HAP and VOC emissions with a control
device (e.g., a carbon adsorber) such that the overall emissions from
the chemical milling maskant operation are equivalent to or less than
the emissions that would be achieved by using compliant chemical milling
maskants at the proposed organic HAP and VOC content levels; or (4) any
combination of the above.
      Compliance with the proposed standard must be shown on a monthly
basis when using all compliant chemical milling maskants and on a daily
basis when averaging across chemical milling maskants.  When a carbon
adsorber is used to comply with the proposed organic HAP and VOC content
levels, compliance must be shown by performing a solvent mass balance
for each rolling material balance period.  The length of the rolling
period will vary from source to source and is determined by the
procedure specified in the proposed rule.  The minimum rolling period is
one day, and the maximum rolling period is 30 days.
      Each control device used for the control of organic HAP or VOC
emissions from primer or topcoat application operations must have an
overall control efficiency, taking into account capture and removal
efficiency, of greater than or equal to 31 percent.  Except for
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Incidental emissions that may escape from the capture system, a control
device cannot be used to control only a portion of emissions from a
coating operation.
1.1.5  Handling and Storage of Waste
      The proposed standard for handling and storage of waste would be
the same for all new and existing facilities.  The proposed rule would
require that the handling and transfer of HAP-containing waste to or
from containers, tanks, vats, vessels, or piping systems be conducted in
such a manner that minimizes spills.  In addition, all HAP-containing
waste would be stored in closed containers.
1.2   ENVIRONMENTAL IMPACT
1.2.1  Estimated Air Emission Reductions
      1.2.1.1  Existing Facilities.  For the existing aerospace OEM and
rework facilities (approximately 2,869 facilities in the base year
1991), the nationwide baseline HAP emissions are estimated to be 189,000
M§/yr (208,000 tpy).  Implementation of the proposed regulation would
reduce these emissions by approximately 112,600 Mg/yr (123,700 tpy), or
59 percent.
      1.2.1.2  New Facilities.  For the aerospace industry, no net
growth is expected over the next five years; therefore, no new
facilities are anticipated during this period.
1.2.2  Estimated Secondary Environmental Impacts
      Secondary environmental impacts are considered to be any air,
water, or solid waste impacts, positive or negative, associated with the
implementation of the proposed standards.  These impacts are exclusive
of the direct air emission reductions discussed in the previous section.
All of the impacts discussed below reflect the maximum increase or
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decrease, as appropriate, that would occur if all of the affected
sources converted to the control option described.
      Secondary air impacts are normally associated with the operation
of certain control devices, primarily incineration systems, whose
exhaust gases may contain air pollutants.  However, none of the
regulatory options considered in the environmental analysis includes
incineration as a likely control measure.  Some product reformulations
that may be used to comply with the proposed standards for hand-wipe
cleaning, primers, and topcoats may contain organic HAPs or VOCs not
present in the original product.  In these cases, different organic HAPs
or VOCs may be emitted as a result of the proposed rule, but the overall
level of these compounds that are emitted will decrease.  Chemical
strippers that do not contain organic HAPs used for depainting may
result in increased VOC emissions when used to replace methylene
chloride-based chemical strippers (methylene chloride is a HAP, but not
a VOC).
      There is a potential for an impact on water quality resulting from
some of the prescribed control measures.  Under baseline conditions for
chemical milling maskant operations, no wastewater is generated;
however, some of the sources may install a carbon adsorber to control
solvent emissions.  If all affected sources use carbon adsorbers, the
amount of water needed to create regenerating steam for these systems,
which will add to the wastewater burden from these sources, is estimated
to be 447 million gallons per year nationwide.  There are two options
available for meeting the proposed rule for depainting operations, both
of which will result in a decrease in the amount of wastewater generated
compared to baseline, which is 251 million gallons per year.  The
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decrease In wastewater nationwide Is estimated to be 251 million gallons
and 86 million gallons if all affected sources use dry media blasting or
chemical strippers that do not contain organic HAPs, respectively.
      Sources installing a carbon adsorption system on their chemical
milling maskant operations would generate additional solid waste due to
the necessity of periodically disposing of spent activated carbon.  If
all affected sources use carbon adsorbers, this added nationwide solid
waste burden is estimated to be 4,500 tons per year, compared to the
baseline of 21,200 tons per year.  Rework facilities that presently use
a methylene chloride-based paint stripper must dispose of 31,300 tons
per year of paint/solvent sludge created by depainting.  A total
conversion to dry media paint removal would produce an increase in the
amount of solid waste composed of dry paint chips and spent blasting
media.  This increase in solid waste is estimated to be 13,280 tons per
year on a nationwide basis.  The proposed standards for the control of
inorganic HAP emissions from primer and topcoat application operations
would result in the increase in solid waste generation from the disposal
of used dry filter media.  The increased solid waste burden is estimated
to be 640 tons per year, compared to the baseline solid waste generation
of 3,540 tons per year.
1.2.3  Estimated Energy Impacts
      Some of the control measures proposed for aerospace manufacturing
and rework operations would lead to increases in energy consumption.
Both of the control options for chemical milling maskant operations,
operation of a carbon adsorber or conversion to waterborne chemical
milling maskant, would involve increased electricity usage (waterborne
chemical milling mas.kants must be cured at elevated temperatures).  The
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total additional energy needed if all affected sources operate new
carbon adsorbers is estimated to be 1.7 billion kilowatt-hours (kWh) per
year, and the energy increase for all affected sources to operate new
curing ovens for waterborne chemical milling maskants is estimated at
324,700 kWh per year.  Baseline energy consumption for chemical milling
maskant operations is considered to be negligible since the use of
solvent-based chemical milling maskants does not directly require the
use of electricity.
      The dry media paint removal systems that would be installed at
rework facilities consume additional energy compared to the solvent
stripping method.  Baseline energy consumption for solvent stripping is
considered to be negligible since the use of these strippers does not
directly require the use of electricity.  The increase in energy
consumption involved in operating dry media blasting systems is
estimated to be 51 million kWh per year.  The use of chemical strippers
that do not contain organic HAPs is essentially the same as the baseline
solvent stripping operation; therefore, no energy impact will result
from their use.
      The proposed standards for the control of inorganic HAP emissions
from primer and topcoat application operations would require some
facilities to install additional spray booths.  These spray booths,
whether equipped with dry filters or waterwash, will increase the energy
consumption of the affected sources.  This increase in energy
consumption is estimated to be 5.9 million kWh per year, compared to the
baseline energy consumption of 117.4 million kWh per year.
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1.3   ECONOMIC IMPACTS (ESTIMATED COST IMPACTS)
      The total capital and annualized control  costs (1992 dollars),
including recovery credits, attributable to compliance with the proposed
standards have been estimated for both existing and new facilities.  The
following two subsections summarize the results of this cost analysis.
1.3.1  Existing Facilities
      1.3.1.1  Capital costs.  Capital costs would be incurred with the
implementation of control measures for chemical milling maskants (both
solvent-based chemical milling maskants with a carbon adsorber and
waterborne chemical milling maskants), dry media blasting for
depainting, spray gun cleaning, and control of inorganic HAP emissions
from primer, topcoat, and depainting operations.  The nationwide capital
costs listed below represent the maximum costs that would be incurred
assuming that all affected sources implemented the specific control
option.
      For carbon adsorbers used in conjunction with solvent-based
chemical milling maskants, the nationwide capital cost is estimated to
be $500 million, and for waterborne chemical milling maskants it is
estimated to be $289 million.  The implementation of dry media blasting
systems for depainting would require a nationwide capital cost of $2.8
billion.  It should be noted that other control measures exist for
depainting other than dry media blasting, such as chemical strippers
that do not contain organic HAPs, that require no capital investment.
Selection of chemical strippers that do not contain organic HAPs by all
affected sources instead of dry media blasting would decrease the total
nationwide capital investment by approximately 82 percent.  The proposed
rule would also require capital costs for high transfer efficiency
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application equipment and spray gun cleaning equipment totalling $130
million and $10 million, respectively.  The control of inorganic HAP
emissions from primer and topcoat application operations would require
the installation of spray booths and filter systems at a capital cost of
$13 million.  The control of inorganic HAP emissions from blast
depainting operations would require the installation of particulate
filtration systems such as baghouses at a capital cost of $54.5 million.
Total nationwide capital costs range from $3.3 billion to $3.5 billion,
depending on which chemical milling maskant control option is used.
      1.3.1.2  Annual costs.  All of the control options will result in
some costs being incurred by the affected .sources.  However, the
annualized cost figures presented below reflect the net cost to
implement the control options after taking into account the costs that
would have been incurred for baseline.  This net cost (MACT cost minus
baseline cost) resulted in an overall cost savings for primers,
topcoats, and high transfer efficiency application methods; spray gun
cleaning; and the use of chemical strippers that do not contain organic
HAPs.  All other options resulted in net annual costs to the affected
sources.  The net cost  (or savings) for all control options reflect the
maximum cost (or savings) that would be incurred assuming all affected
sources implemented the specific control option.
      Only one cost analysis was completed for primers, topcoats, and
high transfer efficiency application methods due to the inter-
relationship between these operations.  For example, high transfer
efficiency application methods will result in a lower volume of primers
and topcoats being applied.  In addition, the organic HAP and VOC limits
on primers and topcoats will, due to higher solids content, also result
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In a lower volume of the coatings being applied.  The reduction In
coating usage due to the lower organic HAP and VOC content had to be
taken Into account first, then the reduction in coating usage due to
high transfer efficiency application methods was applied to this reduced
coating volume to obtain the true overall  reduction in coating usage.
After factoring in the annual 1 zed cost of the coating equipment, the
analysis showed a nationwide cost savings of $218 million for commercial
sources and $10.6 million for military sources.
      The cost savings for primers, topcoats, and high transfer
efficiency application methods is due primarily to labor savings that
would result from the reduced volume of coatings to be applied.  For
example, if it would have taken 15 gallons of primer under baseline
conditions to coat an aircraft and only 12 gallons under MACT
conditions, then the cost analysis assumes a labor savings for the 3
gallons of primer that were not applied.  The EPA has received some
evidence, however, that the labor stays the same or may even increase
with the use of high transfer efficiency application methods
(specifically HVLP spray guns).  The EPA requests comments from
facilities that have converted from conventional spray guns to HVLP
spray guns regarding the labor hours per gallon of coating applied for
each application method.
      Nationwide annual costs are estimated to be $15.3 million for
hand-wipe and flush cleaning, $164 million for solvent-based chemical
milling maskants with a carbon adsorber, $146 million for waterborne
chemical milling maskants, $622 million for depainting with dry media
blasting (or a net savings of $38.8 million if all affected sources used
chemical strippers that contain no organic HAPs), $2.3 million for
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inorganic HAP emissions from primer and topcoat application operations,
and $7.8 million for inorganic HAP emissions from blast depainting
operations.
      Total  nationwide annual costs,  depending on which control options
are chosen,  range from a net savings  of $49.2 million to a net cost of
$660 million.  The majority of this cost differential (97 percent) is a
result of all affected sources using  blast depainting methods rather
than chemical strippers that contain  no organic HAPs.  Due to the high
capital cost of blast depainting equipment, very few facilities are
expected to use this option other than those that already have it.
1.3.2  New Facilities
      For the aerospace industry, no  net growth is expected over the
next five years; therefore, no new facilities are anticipated during
this period.
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                               2.0   INTRODUCTION

2.1   BACKGROUND AND AUTHORITY FOR STANDARDS
      According to industry estimates, more than 2.4 billion pounds of toxic
pollutants were emitted to the atmosphere in 1988 ("Implementation Strategy
for the Clean Air Act Amendments of 1990," EPA Office of Air and Radiation,
January 15, 1991).  These emissions may result in a variety of adverse health
effects, including cancer, reproductive effects, birth defects, and
respiratory illnesses.  Title  III of the Clean Air Act Amendments of 1990
provides the tools for controlling emissions of these pollutants.  Emissions
from both large and small facilities that contribute to air toxics problems in
urban and other areas will be  regulated.  The primary consideration in
establishing national industry standards must be demonstrated technology.
Before national emission standards for hazardous air pollutants (NESHAP) are
proposed as Federal regulations, air pollution prevention and control methods
are examined in detail with respect to their feasibility, environmental
impacts, and costs.  Various control options based on different technologies
and degrees of efficiency are  examined, and a determination is made regarding
whether the various control options apply to each emissions source or if
dissimilarities exist between  the sources.  In most cases, regulatory
alternatives are subsequently  developed that are then studied by EPA as a
prospective basis for a standard.  The alternatives are investigated in terms
of their impacts on the environment, the'economics and well-being of the
industry, the national economy, and energy and other imoacts.  This document
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summarizes the information obtained through these studies so that interested
persons will be able to evaluate the information considered by EPA in
developing the proposed standards.
      National emission standards for hazardous air pollutants for new and
existing sources are established under Section 112 of the Clean Air Act as
amended in 1990 [42 U.S.C. 7401 et seq., as amended by PL 101-549, November
15, 1990], hereafter referred to as the Act.  Section 112 directs the EPA
Administrator to promulgate standards that "require the maximum degree of
reduction in emissions of the hazardous air pollutants subject to this section
(including a prohibition of such emissions, where achievable) that the
Administrator, taking into consideration the cost of achieving such emission
reductions, and any non-air quality health and environmental impacts and
energy requirements, determines is achievable..."  The Act allows the
Administrator to set standards that "distinguish among classes, types, and
sizes of sources within a category or subcategory."
      A major source is defined as "any stationary source or group of
stationary sources located within a contiguous area and under common control
that emits or has the potential to emit considering controls, in the
aggregate, 10 tons per year or more of any hazardous air pollutant or 25 tons
per year or more of any combination of hazardous air pollutants."  The
Administrator, however, may establish a lesser quantity cutoff.  The level of
the cutoff is based on the potency, persistence, or other characteristics or
factors of the air pollutant.  For new sources, the amendments state that the
"maximum degree of reduction in emissions that is deemed achievable for new
sources in a category or subcategory shall not be less stringent than the
emission control that is achieved in practice by the best controlled similar
source, as determined by the Administrator."  Emission standards  Cor existing
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sources "may be less stringent than the standards for new sources in the same
category or subcategory but shall not be less stringent, and may be more
stringent than--
      (A) the average emission limitation achieved by the best performing 12
percent of the existing sources  (for which the Administrator has emissions
information), excluding those sources that have, within 18 months before the
emission standard is proposed or within 30 months before such standard is
promulgated, whichever is later, first achieved a level of emission rate or
emission reduction which complies, or would comply if the source is not
subject to such standard, with the lowest achievable emission rate (as defined
by Section 171) applicable to the source category and prevailing at the time,
in the category or subcategory for categories and subcategories with 30 or
more sources, or
      (B) the average emission limitation achieved by the best performing five
source (for which the Administrator has or could reasonably obtain emissions
information) in the category or  subcategory for categories or subcategories
with fewer than 30 sources."
      The Federal standards are  also known as "MACT" standards and are based
on the maximum achievable control technology previously discussed.  The MACT
standards may apply to major sources, although the existing source standards
may be less stringent than the new source standards, within the constraints
presented above.  The MACT is considered to be the basis for the standard, but
the Administrator may promulgate more stringent standards, which have several
advantages.  First, they may help achieve long-term cost savings by avoiding
the need for more expensive retrofitting to meet possible future residual risk
standards, which may be more stringent (discussed in Section 2.7).  Second,
Congress was clearly interested  in providing incentives for improving

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technology.  Finally,  in the Clean Air Act Amendments of 1990,  Congress gave
EPA a clear mandate to reduce the health and environmental  risk of air toxics
emissions as quickly as possible.
      The standards for hazardous air pollutants  (HAP's),  like  the new source
performance standards  (NSPS) for criteria pollutants required by Section 111
of the Act (42 U.S.C.  7411), differ from other regulatory programs required by
the Act (such as the new source review program and the prevention of
significant deterioration program) in that NESHAP and NSPS are  national in
scope (versus site-specific).  Congress intended  for the NESHAP and NSPS
programs to provide a degree of uniformity to State regulations to avoid
situations where some States may attract industries by relaxing standards
relative to other States.  States are free under  Section 116 of the Act to
establish standards more stringent than Section 111 or 112 standards.
      Although NESHAP are normally structured in  terms of numerical emissions
limits, alternative approaches are sometimes necessary.  In some cases,
physically measuring emissions from a source may  be impossible  or at least
impracticable due to technological and economic limitations.  Section 112(h)
of the Act allows the Administrator to promulgate a design, equipment, work
practice, or operational standard, or combination thereof,  in those cases
where it is not feasible to prescribe or enforce  an emissions standard.  For
example, emissions of volatile organic compounds  (many of which may be HAP's,
such as benzene) from storage vessels for volatile organic liquids are
greatest during tank filling.  The nature of the  emissions (i.e., high
concentrations for short periods during filling and low concentrations for
longer periods during storage) and the configuration of storage tanks make
direct emission measurement impractical.  Therefore, the MACT standards may be
based on equipment specifications.
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      Under Section 112(h)(3), the Act also allows the use of alternative
equivalent technological systems:  "If, after notice and opportunity for
comment, the owner or operator of any source establishes to the satisfaction
of the Administrator that an alternative means of emission limitation" will
reduce emissions of any air pollutant at least as much as would be achieved
under the design, equipment, work practice, or operational standard, the
Administrator shall permit the use of the alternative means.
      Efforts to achieve early environmental benefits are encouraged in Title
III.  For example, source owners and operators are encouraged to use the
Section 112 (i)(5) provisions, which allow a 6-year compliance extension of
the MACT standard in exchange for the implementation of an early emission
reduction program.  The owner or operator of an existing source must
demonstrate a 90 percent emission reduction of HAP's (or 95 percent if the
HAP's are particulates) and meet an alternative emission limitation,
established by permit, in lieu of the otherwise applicable MACT standard.
This alternative limitation must reflect the 90 (95) percent reduction and is
in effect for a period of 6 years from the compliance date for the otherwise
applicable standard.  The 90  (95) percent early emission reduction must be
achieved before the otherwise applicable standard is first proposed, although
the reduction may be achieved after the standard's proposal (but before
January 1, 1994) if the source owner or operator makes an enforceable
commitment before the proposal of the standard to achieve the reduction.  The
source must meet several criteria to qualify for the early reduction standard,
and Section 112(i)(5)(A) provides that the State may require additional
reduction.
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2.2   SELECTION OF POLLUTANTS AND SOURCE CATEGORIES
      As amended in 1990, the Act includes a list of 189 HAP's.   Petitions to
add or delete pollutants from this list may be submitted to EPA.   Using this
list of pollutants, EPA will publish a list of source categories  (major
sources) for which emission standards will be developed.  Within  2 years of
enactment (November 1991), EPA will  publish a schedule establishing dates for
promulgating these standards.  Petitions may also be submitted to EPA to
remove source categories from the list.  The schedule for standards for source
categories will be determined according to the following criteria:
      "(A) the known or anticipated adverse effects of such pollutants on
public health and the environment;
      (B) the quantity and location of emissions or reasonably anticipated
emissions of hazardous air pollutants that each category or subcategory will
emit; and
      (C) the efficiency of grouping categories or subcategories  according to
the pollutants emitted, or the processes or technologies used."
      After the source category has been chosen, the types of facilities
within the source category to which the standard will apply must  be
determined.  A source category may have several facilities that cause air
pollution, and emissions from these facilities may vary in magnitude and
control cost.  Economic studies of the source category and applicable control
technology may show that air pollution control is better served by applying
standards to the more severe pollution sources.  For this reason, and because
there is no adequately demonstrated system for controlling emissions from
certain facilities, standards often do not apply to all facilities at a
source.  For the same reasons, the standards may not apply to all air
pollutants emitted.  Thus, although a source category may be selected to be
                                      2-6

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covered by standards, the standards may not cover all pollutants or facilities
within that source category.
2.3   PROCEDURE FOR DEVELOPMENT OF NESHAP
      Standards for major sources must (1) realistically reflect MACT; (2)
adequately consider the cost, the non-air quality health and environmental
impacts, and the energy requirements of such control; (3) apply to new' and
existing sources; and (4) meet these conditions for all variations of industry
operating conditions anywhere in the country.
      The objective of the NESHAP program is to develop standards to protect
the public health by requiring facilities to control emissions to the level
achievable according to the MACT guidelines.  The standard-setting process
involves three principal phases of activity:  (1) gathering information,
(2) analyzing the information, and (3) developing the standards.
      During the information-gathering phase, industries are questioned
through telephone surveys, letters of inquiry, and plant visits by EPA
representatives.  Information is also gathered from other sources, such as a
literature search.  Based on the information acquired about the industry, EPA
selects certain plants at which emissions tests are conducted to provide
reliable data that characterize the HAP emissions from well-controlled
existing facilities.
      In the second phase of a project, the information about the industry,
the pollutants emitted, and the control options are used in analytical
studies.  Hypothetical "model plants" are defined to provide a common basis
for analysis.  The model plant definitions, national pollutant emissions data,
and existing State regulations governing emissions from the source category
are then used to establish  "regulatory alternatives."  These regulatory
                                      2-7

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alternatives may be different levels of emissions control  or different degrees
of applicability or both.
      From several  alternatives,  EPA selects the single most plausible
regulatory alternative as the basis for the NESHAP for the source category
under study.  The EPA then conducts studies to determine the cost, economic,
environmental, and energy impacts of this regulatory alternative.
      In the third phase of a project,  the selected regulatory alternative is
translated into standards, which, in turn, are written in the form of a
Federal regulation.  The Federal  regulation limits emissions to the levels
indicated in the selected regulatory alternative.
      As early as is practical in each  standard-setting project, EPA
representatives discuss the possibilities of a standard and the form it might
take with representatives from industry, environmental groups, and State and
local air pollution control agencies.  Other interested parties also
participate in these meetings.
      The information acquired in the project is summarized in the background
information document (BID).  The BID is widely circulated to the industry
being considered for control, environmental groups, other government agencies,
and offices within EPA.  Through this extensive review process, the points of
view of expert reviewers are taken into consideration as changes are made to
the documentation.
      A "proposal package" is assembled and sent through the offices of EPA
Assistant Administrators for concurrence before the proposed standards are
officially enforced by the EPA Administrator.  After being approved by the EPA
Administrator, the preamble and the proposed regulation are published in the
Federal Register.
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      The public is invited to participate in the standard-setting process as
part of the Federal Register announcement of the proposed regulation.  The EPA
invites written comments on the proposal  and also holds a public hearing to
discuss the proposed standards with interested parties.  All public comments
are summarized and incorporated into a second volume of the BID.  All
information reviewed and generated in studies in support of the standards is
available to the public in a "docket" on  file in Washington, D.C.  Comments
from the public are evaluated, and the standards may be altered in response to
the comments.
      The significant comments and EPA's  position on the issues raised are
included in the preamble of a promulgation package, which also contains the
draft of the final regulation.  The regulation is then subjected to another
round of internal EPA review and refinement until it is approved by the EPA
Administrator.  After the Administrator signs the regulation, it is published
as a "final rule" in the Federal Register.
2.4   CONSIDERATION OF COSTS
      The requirements and guidelines for the economic analysis of proposed
NESHAP are prescribed by Presidential Executive Order 12291 (EO 12291) and the
Regulatory Flexibility Act (RFA).  The EO 12291 requires preparation of a
Regulatory Impact Analysis (RIA) for all  "major" economic impacts.  An
economic impact is considered to be major if it satisfies any of the following
criteria:
      1.  An annual effect on the economy of $100 million or more;
      2.  A major increase in costs or prices for consumers; individual
industries; Federal, State, or local government agencies; or geographic
regions; or
                                      2-9

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      3.   Significant adverse effects on competition,  employment,  investment,
productivity,  innovation, or on the ability of United States-based enterprises
to compete with foreign-based enterprises in domestic or export markets.
      An  RIA describes the potential  benefits and costs of the proposed
regulation and explores alternative regulatory and nonregulatory approaches to
achieving the desired objectives.   If the analysis identifies less costly
alternatives,  the RIA includes an  explanation of the legal reasons why the
less costly alternatives could not be adopted.  In addition to requiring an
analysis  of the potential costs and benefits, EO 12291 specifies that EPA, to
the extent allowed by the CAA and  court orders, demonstrate that the benefits
of the proposed standards outweigh the costs and that the net benefits are
maximized.
      The RFA requires Federal agencies to give special consideration to the
impact of regulations on small businesses, small organizations, and small
governmental units.  If the proposed regulation is expected to have a
significant impact on a substantial number of small entities, a regulatory
flexibility analysis must be prepared.  In preparing this analysis, EPA takes
into consideration such factors as the availability of capital for small
entities, possible closures among  small entities, the increase in production
costs due to compliance, and a comparison of the relative compliance costs as
a percent of sales for small versus large entities.
      The prime objective of the cost analysis is to identify the incremental
economic impacts associated with compliance with the standards based on each
regulatory alternative compared to baseline.  Other environmental  regulatory
costs may be factored into the analysis wherever appropriate.  Air pollutant
emissions may cause water pollution problems, and captured potential air
pollutants may pose a solid waste  disposal problems.  The total environmental
                                     2-10

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impact of an emission source must, therefore, be analyzed and the costs
determined whenever possible.
      A thorough study of the profitability and price-setting mechanisms of
the industry is essential to the analysis so that an accurate estimate of
potential adverse economic impacts can be made for proposed standards.  It is
also essential to know the capital requirements for pollution control systems
already placed on plants so that the additional capital requirements
necessitated by these Federal standards can be placed in proper perspective.
Finally, it is necessary to assess the availability of capital to provide the
additional control equipment needed to meet the standards.
2.5   CONSIDERATION OF ENVIRONMENTAL IMPACTS
      Section 102(2)(C) of the National Environmental Policy Act (NEPA) of
1969 requires Federal agencies to prepare detailed environmental impact
statements on proposals for legislation and other major Federal actions
significantly affecting the quality of the human environment.  The objective
of NEPA is to build into the decision-making process of Federal agencies a
careful consideration of all environmental aspects of proposed actions.
      In a number of legal challenges to standards for various industries, the
United States Court of Appeals for the District of Columbia Circuit has held
that environmental impact statements need not be prepared by EPA for proposed
actions under the Clean Air Act.  Essentially, the Court of Appeals has
determined that the best system of emissions reduction requires the
Administrator to take into account counterproductive environmental effects of
proposed standards as well as economic costs to the industry.  On this basis,
therefore, the Courts established a narrow exemption from NEPA for EPA
determinations.
                                     2-11

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      In addition to these judicial  determinations,  the Energy Supply and
Environmental Coordination Act (ESECA)  of 1974 (PL-92-319) specifically
exempted proposed actions under the  Clean Air Act from NEPA requirements.
According to Section 7(c)(l), "No action taken under the Clean Air Act shall
be deemed a major Federal action significantly affecting the quality of the
human environment within the meaning of the National Environmental Policy Act
of 1969" (15 U.S.C. 793(c)(l)).
      Nevertheless, EPA has concluded that preparing environmental impact
statements could have beneficial effects on certain regulatory actions.
Consequently, although not legally required to do so by Section 102(2)(C) of
NEPA, EPA has adopted a policy requiring that environmental impact statements
be prepared for various regulatory actions, including NESHAP developed under
Section 112 of the Act.  This voluntary preparation of environmental impact
statements, however, in no way legally subjects the EPA to NEPA requirements.
      To implement this policy, a separate action is included in this document
that is devoted solely to an analysis of the potential environmental impacts
associated with the proposed standards.  Both adverse and beneficial impacts
in such areas as air and water pollution, increased solid waste disposal, and
increased energy consumption are discussed.
2.6   RESIDUAL RISK STANDARDS
      Section 112 of the Act provides that 8 years after MACT standards are
established  (except for those standards established 2 years after enactment,
which have 9 years), standards to protect against the residual health and
environmental risks remaining must be promulgated, if necessary.  The
standards would be triggered if more than one source in a category or
subcategory exceeds a maximum individual risk of cancer of 1 in 1 million.
These residual risk regulations would be based on the concept of providing  an
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"ample margin of safety to protect public  health."  The Administrator may also
consider whether a more stringent standard is  necessary to prevent--
considering costs, energy, safety, and  other relevant  factors—an adverse
environmental effect.
                                     2-13

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              3.0  AEROSPACE MANUFACTURING AND REWORK OPERATIONS

3.1   GENERAL
      The aerospace industry being evaluated includes all manufacturing
facilities that produce an aerospace vehicle or component and all  facilities
that rework or repair these aerospace products.  Aerospace vehicle or
component is defined as any fabricated part, processed part, assembly of
parts, or completed unit of any aircraft including, but not limited to,
airplanes, helicopters, missiles, rockets, and space vehicles.  Facilities
that also conduct non-aerospace work may be subject to the proposed rule,
regardless of the relative proportion of aerospace and non-aerospace work at
the facility.  In addition to manufacturing and rework facilities, some shops
may specialize in providing a service, such as chemical milling, rather than
actually producing a component or assembly.
      In general, aerospace manufacturing and rework facilities are covered by
the SIC codes listed in Table 3-1.  However, facilities classified under other
SIC codes may be subject to the proposed rule if the facility meets the
definition of a major source and the definition of an aerospace manufacturing
or rework facility.
      Aerospace facilities may be divided into four market segments:
commercial original equipment manufacturers (OEM), commercial rework
facilities, military OEMs, and military rework facilities.  The commercial OEM
segment of the market includes the manufacturing of commercial aircraft as
well as the production of business and private aircraft.  The military OEM
                                      3-1

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            Table 3-1
Aerospace Manufacturing SIC Codes
SIC Code
3720
3721
3724
3728
3760
3761
3764
3769
Description
Aircraft and Parts
Aircraft
Aircraft Engines and Engine Parts
Aircraft Parts and Equipment
Guided Missiles, Space Vehicles,
and Parts
Guided Missiles and Space
Vehicles
Space Propulsion Units and Parts
Space Vehicle Equipment
     Aerospace Rework SIC  Code
SIC Code
4581
Description
Airports
, Flying Fields,
Services
and
               3-2

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segment of the market includes military installations and defense contractors
that manufacture aircraft, missiles, rockets,  satellites, and spacecraft.
Rework facilities, both commercial and military, may rework many of the above
end products.
      Based on information obtained through the Federal Aviation
Administration and the U.S. Department of Commerce - Bureau of the Census,1'2
there are an estimated 2,869 aerospace facilities that will be subject to the
proposed standard.  Of this number, 1,395 produce or rework commercial
products, and 1,474 produce or rework military products.  The combined
hazardous air pollutant (HAP) emissions from these facilities are estimated to
be over 280,000 Mg/yr (310,000 tons/yr).
      In addition to these facilities, there are numerous subcontractors that
manufacture or rework aerospace vehicles or components.  The subcontractors
may work directly for the OEM or rework facilities, or indirectly through
first line subcontractors.  As most of these subcontractors perform various
types of work, they are often classified under non-aerospace SIC codes.
Consequently, an estimate of the number of subcontractors cannot be made.  One
company alone, however, employs the services of over 5,000 subcontractors.
      Aerospace manufacturing facilities and rework operations are typically
located in or near industrial centers in areas of medium to high population
density.  Some states with large numbers of aerospace manufacturers are
California, Texas, Connecticut, Florida, and Washington.  Figure 3-1 presents
the number of aerospace manufacturing facilities by state.
      Aerospace manufacturing facilities range in size from small shops that
produce a single aerospace component, such as propellers, to large
corporations that produce the entire aircraft.  Aerospace rework facilities,
                                      3-3

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however, are usually large facilities that must be able to rework or repair
every facet of several models of large commercial or military aircraft.
      The hours of operation at aerospace manufacturing and rework facilities
may vary greatly due to the production backlog at each facility.  The hours of
operation may range from 8 hours (or less) per day, 5 days per week, to 24
hours per day, 7 days per week.
3.2   PROCESS DESCRIPTION
      Aerospace manufacturing and rework operations consists of the following
basic operations:  materials receiving, machining and mechanical processing,
chemical milling maskant application, chemical milling, heat treating,
sealing, adhesive bonding, hand-wipe cleaning, spray equipment cleaning, metal
finishing, coating application, coating removal (depainting),
electrodeposition (metal plating), composite processing, and testing.  Many
aerospace manufacturing and rework facilities may employ all of these
processes in their operations, as with an OEM facility that produces the
entire  aircraft.  However, an aerospace facility may only employ a subset of
these operations, as with a facility that produces a single component or
assembly, or a facility that provides a service such as chemical milling.
      The following sections discuss thirteen general process categories.
These categories are  intended to cover all of the aerospace processes found at
OEM and rework facilities.3
3.2.1   Materials Receiving
      Materials used  in aerospace manufacturing and rework fall into one of
two general categories:  materials to form parts, and coatings and chemicals.
The most common materials are alloys of aluminum, which are used primarily for
aircraft structural components and exterior skin sections.  Other materials
are titanium, stainless steel, magnesium, and non-metal!ics such as plastics,
                                      3-5

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fabrics, and composite materials.  Typical  forms of materials are honeycomb,
wire mesh, plate, sheet stock, bar cast,  and forged material.  Also received
in this area are procured hardware (e.g., fasteners, rivets, and screws),
fabricated parts, and assemblies.  These materials are stored in a general
storage area.
      Minor processing of materials may occur in the receiving area.  Examples
of these operations are application of temporary protective coatings and oils
to inhibit corrosion, and application of stenciled or stamped identification
markings.  Typically, no processing is done to coatings and chemicals in
materials receiving.
3.2.2  Machining and Mechanical Processing
      3.2.2.1  Machining.  Materials may first require rough-cutting to a
configuration approximating the size and shape of the final part.  The raw or
rough-cut materials are machined by milling, cutting, grinding, routing, or
drilling to produce the final shape of the part.  Sheet stock may be cut into
the desired shapes using either a laser or knife-type cutter.  Machined parts
cover a wide variety of shapes and sizes, ranging from a small flat plate to a
complex structural framework.  Machining oils and coolants are used to
lubricate and cool the parts and tools, and to carry away the machined chips.
After machining, some parts are coated with an anti-rust oil, wrapped in a
protective material, and put in storage to await further processing.  Other
parts are processed further as discussed below.
      3.2.2.2  Deburring.  Deburring involves removing metal shavings and
burrs clinging to the cut edges of parts after machining has been completed.
Deburring is typically one of two processes.  Small parts can be deburred in a
tumbler where the burrs are smoothed off the part by the constant friction
with the tumbling media.  This process, however, is not appropriate for long
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parts.   Instead, long parts are scrubbed with an abrasive pad by hand or
buffed with a power tool.  The buffing operation can be performed either by
hand or in an automatic operation.
      3.2.2.3  Forming.  Forming is the process in which machined component
parts or bar and flat stock material are mechanically shaped to fit required
specifications.  Examples of forming processes are bending, flaring, stamping,
forging, and fitting.
      Machined components and flat stock are formed by placing the part
between two halves of a mold, then pressing the mold together using high
pressure.  This shapes the part to the configuration of the mold.  Release
agents  (either dry or liquid coatings) are typically applied to the part and
the mold to prevent the part from sticking to the mold.  Bar stock is formed
by bending to the desired shape.
      3.2.2.4  Welding.  Welding  is used to build permanent assemblies
composed of a single metal or alloy.  Some of these processes are tungsten-
inert gas welding, metal-inert gas welding, heliarc, electron beam, and arc
welding using manual or  semi-automated equipment.  Welding is performed before
or after machining depending on the configuration requirements of the
individual part.  Each subassembly unit is ink stamped with a part number for
identification.
3.2.3   Maskant Application and Chemical Milling
      3.2.3.1  Maskant Application.  Maskants are coatings that are applied to
a part  to protect the  surface from chemical milling (see Section 3.2.3.2) and
surface treatment processes  subsequent to chemical milling such as anodizing,
plating, etching, and  bonding.  Maskants are typically rubber- or polymeric-
based substances  (similar to common rubber cement) applied to an entire part
or subassembly  by brushing,  dipping, spraying, or flow coating.  Two major
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types of maskants are used: solvent-based and waterborne.   Before the maskant
can be applied to the part, the surface must be thoroughly cleaned and
prepared, usually by the following three step process:  (1) alkaline cleaning,
the removal of dirt, oils, and grease with the use of an alkaline cleaner, (2)
pickling, the removal of scale with inorganic acids, and (3) surface
passivation, the chemical formation of an oxide layer.  These three steps
ensure a uniform removal of metal in the chemical milling process and provide
adequate surface adhesion between the part and the masking agent.4  After an
adequate thickness of maskant has been applied to the part, the maskant is
cured in a bake oven.  The maskant is then cut following a specific pattern
(called "scribing") and manually stripped away from selected areas of the part
where metal is to be removed.  The maskant remaining on the part protects
those areas from the etching solution (etchant).
      3.2.3.2  Chemical Milling.  Chemical milling is used to reduce the
thickness of selected areas of metal parts in order to reduce weight.  The
process is typically used when the size or shape of parts precludes mechanical
milling or when chemical milling is advantageous due to shorter processing
time or its batch capability.
      Chemical milling  is accomplished by submerging the component in an
appropriate etchant.  Commonly used etchants are sodium hydroxide for
aluminum, nitric acid and hydrofluoric acid for titanium, dilute sulfuric acid
for magnesium, and aqua regia (a mixture of nitric and hydrochloric acids) for
stainless steel.  Since the concentration of the solution affects the milling
rate, it must be closely controlled to obtain the desired rate.  The depth of
the cut is controlled by the length of time the component is in the etchant
and the concentration of the etchant.  When the milling has been completed,
the part is removed from the etchant and rinsed with water.  Some metals may
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develop a smutty discoloration during the chemical milling process.  A
brightening solution, such as dilute nitric acid, is typically used as a final
step in the process to remove the discoloration.5  The process of removing
discoloration is referred to as "desmutting."  After desmutting, the part
either goes back to chemical milling for further metal removal or to the
stripping area to have the maskant removed.  The maskant may be softened in a
solvent solution and then stripped off by hand.
3.2.4  Heat Treating
      Heat treating  is the process of changing a material's or part's
metallurgical properties prior to coating or assembly.  For example, aluminum
outer skin panels undergo a low temperature oven bake after forming to provide
greater stress tolerance.  Heat treating can be performed either before or
after machining and  includes carburizing (impregnating the surface with
carbon), annealing (softening), stress relief, tempering, air furnace
treating, and salt pot treating.  Compounds, such as methanol, are often used
in heat treating ovens to maintain a chemically reducing atmosphere in order
to obtain the proper metallurgical properties on the surface of the part being
treated.  After heat treating, the parts can either be cooled in ambient air
or placed in a liquid quenching bath.  The quench bath is typically a glycol
solution, a chromate solution, or an oil.
3.2.5  Sealing
      Sealants, predominately composed of polysulfide, are applied throughout
the aircraft structure primarily to seal out moisture and contaminants in
order to prevent corrosion, such as on faying  (i.e., closely or tightly
fitting) surfaces, inside holes and slots, and around installed fasteners.
They are also used to seal fuel tank cells.  Sealants are applied using tubes,
spatulas, brushes, rollers, or spray guns.  Sealants are often stored frozen
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and thawed before use, and many are two-component mixtures that cure after
mixing.  Often a sealant is applied before assembly or fastener installation,
and the excess is squeezed out or extruded from between the parts as assembly
is completed.  This ensures a moisture-tight seal between the parts.  Solvents
are often added to sealants to aid in achieving the proper application
consistency.
3.2.6  Adhesive Bonding
      Adhesive bonding involves the joining together of two or more metal or
non-metal components, such as the splicing of two pieces of a honeycomb core
or the joining of skins to a honeycomb core.  This process is typically
performed when the joints being formed are essential to the structural
integrity of the aircraft.  Bonding surfaces are typically roughened
mechanically or etched chemically to provide increased surface area for
bonding and then chemically treated to provide a stable corrosion resistant
oxide layer.  The surfaces are then coated with an adhesive bonding primer in
a thin film (0.1 to 0.5 millimeter) to promote adhesion and protect from
subsequent corrosion.  Structural adhesives are applied as either a thin film
or as a paste.  The parts are joined together and cured either at ambient
temperature or in an  autoclave to activate the adhesive and provide a
permanent bond between the components.6
3.2.7  Cleaning
      3.2.7.1  Hand-wipe and flush cleaning.  Aerospace components  are cleaned
frequently during manufacturing to remove contaminants such as dirt, grease,
and oil, and to prepare the components for the next operation.  Cleaning is
typically performed by a hand wiping process using a wide variety of cleaning
solvents.  Assemblies and parts with concealed or  inaccessible areas may be
flush cleaned by pouring the cleaning agent over and into the part.  The
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cleaning agent is then drained from the part and the procedure is repeated as
many times as necessary to ensure the required cleanliness.
      3.2.7.2  Spray gun and coating line cleaning.  Spray guns and coating
lines used to apply the various coatings used at aerospace facilities must be
cleaned when switching from one coating to another and when they are not going
to be immediately reused.  The cleaning of spray guns can be performed either
manually or with enclosed spray gun cleaners.  Manual cleaning involves
disassembling the gun and placing the parts in a vat containing an appropriate
cleaning solvent.  The residual paint is brushed or wiped off the parts.
After reassembling, the cleaning solvent may be sprayed through the gun for a
final cleaning.  Coating lines are cleaned by passing the cleaning solvent
through the lines until all coating residue is removed.
      Enclosed spray gun cleaners are self-contained units that pump the
cleaning solvent through the gun within a closed chamber.  After the cleaning
cycle is complete, the guns are removed from the chamber and typically undergo
some manual cleaning to remove coating residue from areas not exposed to the
cleaning solvent, such as the seals under the atomizing cap.
      Cleaning agents for hand-wipe, flush, and spray equipment cleaning
consist of solvents such as methyl ethyl ketone, methyl isobutyl ketone,
toluene, or various solvent blends.  Chlorinated hydrocarbons, such as 1,1,1-
trichloroethane and trichloroethylene, are also often used.  Some cleaners
that contain little or no HAPs, particularly citrus-based cleaners or
saponified aqueous (soapy water) solutions, are in use or under trial for
hand-wipe cleaning at many facilities.
3.2.8  Metal Finishing
      Metal finishing processes are used to prepare the surface of a part for
better adhesion, improved surface hardness, and improved corrosion resistance.
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Typical metal finishing operations include conversion coating, anodizing,
passivation, pickling, alkaline cleaning, deoxidizing, desmutting, descaling,
polishing, abrasive cleaning, shot-peening, or any operation that mechanically
or chemically affects the surface layer of a part.  Hydrochloric acid, nickel
chloride, sodium cyanide, chromic conversion, and other solutions may be
applied to a variety of metal substrates before other surface operations may
proceed.  After leaving the process lines, many parts are placed in a hot air
dryer to remove residual moisture.  Specific surface preparation processes are
discussed below.
      3.2.8.1  Conversion Coating.  Conversion coating is the process of
changing a metal's surface characteristics by applying a reactive chemical to
the metal's surface or by reacting the metal in a chemical bath.7  The desired
result is improved coating adhesion, increased corrosion resistance, or both.
The parts are typically prepared for these operations by alkaline cleaning,
rinsing to neutralize and remove the alkaline cleaning solution, acid etching
to prepare the surface, and rinsing to remove the etching solution.  After
these preparation steps, the conversion coating is applied by immersing,
brushing, spraying, or wiping.8
      3.2.8.2  Anodizing.  Anodizing is the electrochemical treatment of
aluminum, magnesium, and other select metals in order to form an oxide layer
on the surface of the metal.  This is used to protect a part from corrosion
and increase the part's electrical insulation.9  Anodizing involves immersing
the part in a solution typically containing chromic acid or sulfuric acid.  A
direct electrical current is applied such that the part is the negative
terminal, or anode.  Afterwards, the part is rinsed and then immersed in hot
water or a hot dilute solution of sodium dichromate to seal the anodized
surface.  The part may then be sent to an oven for drying.
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      3.2.8.3  Passivation.  Passivation is a chemical process in which parts
are immersed in a solution containing a strong oxidizing agent.  This forms a
thin oxide layer on the part surface, providing corrosion protection and
increasing adhesion of subsequent coatings.  It is often used before maskant
application in the chemical milling process.
      3.2.8.4  Pickling.  Pickling is the chemical process of removing oxides
from metal surfaces.  Parts are immersed in an inorganic acid solution,
generally hydrochloric, phosphoric, or sulfuric acid.  The rate of removal is
affected by concentration, temperature, and electrolysis.  The usual solution
has a concentration of 15 percent acid at or above 100°C (212°F).10
      3.2.8.5  Alkaline Cleaning.  Alkali-ne cleaning is typically a tank bath
process in which parts are immersed in a solution containing a strong alkaline
agent.  Alkaline cleaning is used to remove dirt, oils, and grease.
      3.2.8.6  Deoxidizing, Desmutting, and Descaling.  Deoxidizing,
desmutting, and descaling are acidic or alkaline metal cleaning processes.
Deoxidizing and desmutting remove thin oxide layers from metal surfaces.  A
specific example of deoxidizing is brightening, an acidic process used after
chemical milling to smooth and enhance the appearance of a metal surface.
Descaling is the process of removing thick oxide layers or deposits from metal
surfaces.11   Example operations  are chrome  deoxidizing,  chrome desmutting,
acid etching, permanganate descaling, molten salt descaling, hydrofluoric
acid/nitric acid descaling, hydrochloric acid descaling, and nitric acid
descaling/passivation.
      3.2.8.7  Polishing.  Polishing is used at some facilities to clean and
finish the outer skin of the aircraft.  The polish is a lightly abrasive metal
cleaner that is buffed on the metal surface, then wiped off.  The polish gives
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a mirror-like surface finish and is usually applied instead of paint.
Polishing can also be used on other metal parts as a cleaning step.
      3.2.8.8  Abrasive Cleaning.  Abrasive cleaning cleans surfaces with
abrasive media such as rough fabric scrubbing pads or sandpaper.  Abrasive
cleaning is used instead of, or in addition to, deoxidation.  This operation
removes corrosion and slightly roughens the surface to prepare for painting.
      3.2.8.9  Mechanical Surface Preparation.  Mechanical surface preparation
is the process of mechanically hardening the surface of a metal part.  One
example process often used by the industry is shot-peening.  Shot-peening is a
process where a metal part is blasted with small media (or shot).
3.2.9  Coating Application
      A coating is a material that is applied to the surface of a part to form
a decorative or functional solid film.12  The  most  common  coatings  are  the
broad categories of non-specialized primers and topcoats.  There are also
numerous specialty coatings ranging from temporary protective  coatings to
radiation effect coatings designed to shield aircraft from radar detection.
      Coatings are applied to aerospace vehicles or components using several
methods of application.  These are spraying, brushing, rolling, flow coating,
and dipping.  Spray application systems include conventional air spray,
airless spray, air-assisted airless, electrostatic, and high-volume low-
pressure (HVLP) spray.  These latter two methods are generally accepted as
having better transfer efficiency than the other spraying methods and are
gaining increased use as a means of using less coating and, hence, reducing
emissions.
      Nearly all aerospace coatings contain a mixture of organic solvents,
many of which are HAPs.  The most common HAP solvents used in coatings are
toluene, xylene, methyl ethyl ketone, trichloroetnylene, and 1,1,1-
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trichloroethane.  The HAP content ranges differ for the various coating
categories.  High solids coatings and waterborne coatings, which generally
contain less solvent than the solvent-based coatings, are slowly becoming
accepted in the industry.  Powder coatings, which do not contain solvents, are
applied electrostatically as a dry powder and then cured.  Powder coatings
presently have limited use in the aerospace industry.  A detailed discussion
of coating substitutions is presented in Section 4.1.1.1.
3.2.10  Coating Removal  (Depainting)
      The depainting operation involves the removal of coatings from the outer
surface of the aircraft.  The two basic types are chemical depainting and
blast depainting.  Methylene chloride is the most common chemical stripper
solvent.  Chemical depainting agents are applied to the aircraft, allowed to
degrade the coating, and then scraped or washed off with the coating residue.
Blast depainting methods utilize a media such as plastic, wheat starch, carbon
dioxide (dry ice), or high pressure water to remove coatings by physically
abrading the coatings from the surface of the aircraft.  Grit blasting and
sand/glass blasting are  also included in this category.  High intensity
ultraviolet light stripping has been developed for use in conjunction with
carbon dioxide methods and is under development at several facilities.
3.2.11  Electrodeposition (Metal Plating)
      Electrodeposition  is an additive process for metal substrates in which
another metal layer is added to the substrate in order to enhance corrosion
and wear resistance necessary for the successful performance of a component.
The two types of electrodeposition typically used are electroplating and
plasma arc spraying.
      Electroplating is  a multi-step process where the part to be plated  is
first immersed  in a series of chemical baths to clean and etch the surface of
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the part.  The part is then immersed in the electroplating solution and a
direct electrical  current applied such that the part is the positive terminal,
or cathode.  The electroplating solution is an  acidic solution containing a
dissolved salt of the metal to be plated (e.g., copper sulfate for a copper
plating solution).  Soluble anodes of the metal being plated are immersed in
the electroplating solution on either side of the part.  The plating thickness
is controlled primarily by the amount of current applied and the plating time.
      The plasma arc spray process melts powdered metal materials using plasma
(hot ionized gas)  as a heat source.  A gas or gas mixture is passed through an
electric arc between a cathode and an orifice in an anode.  The gas passing
through the orifice is heated to temperatures much higher than those obtained
with a combustion flame.  During heating, the gas is partially ionized,
producing a plasma.  As the plasma exits the orifice, disassociated molecules
of diatomic gases recombine and liberate heat.   A metallic powder is then
introduced into the plasma, melted, and propelled onto the work piece by the
high velocity stream of gases.  The resulting coating is very hard and wear
resistant.13
      The aerospace industry uses a wide variety of metals for
electrodeposition including nickel, zinc, chromium, cadmium, copper, tin, and
silver.  Of these, nickel, chromium, and cadmium compounds are HAPs.
3.2.12  Composites Processing
      The aerospace industry is increasingly substituting composites for
metals in aircraft and space, vehicles due to the superior strength-to-weight
ratio, corrosion resistance, and fatigue life of composites.  Composites are
comprised of a resin matrix that bonds together layers of reinforcing
material.  The resultant structure has mechanical properties superior to each
individual component.14  The resin  matrix is  usually  a  polymeric  material  such
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as epoxy,  polyester,  nylon, or phenolic.   The reinforcing material or fiber is
usually carbon (graphite), fiberglass, or Kevlar®.  The fibers are oriented at
specific angles within the matrix to achieve desired strength characteristics.
      Methods of forming composites include: injection molding, compression
molding, and hand lay-up (or wet lay-up).  Hand lay-up can involve applying
resin on pre-woven fibers or can involve stacking thin sheets of pre-
impregnated (prepreg) fiber material.  Steps in hand lay-up are typically:
lay-up, debulking, curing, and tear-down (break-out).
      3.2.12.1  In.iection Molding.  Injection molding is the process of
shaping a material by applying heat and utilizing the pressure created by
injecting a resin into a closed mold.15
      3.2.12.2  Compression Molding.  Compression molding is the process of
filling a mold with molding compound, closing the mold, and applying heat and
pressure until the material has cured.16
      3.2.12.3  Lav-up.  Lay-up is the process of assembling composite parts
by positioning reinforcing material in a mold and impregnating the material
with resin.17  With hand lay-up,  reinforcing material  with  resin  or prepreg  (a
composite fabric which  is precoated with resin) can be added to an open mold
until the design thickness and contours are achieved.18
      3.2.12.4  Debulking.  Debulking is the simultaneous application of low-
level heat and pressure to composite materials to force out excess resin,
trapped air, vapor, and volatiles from between the layers of the composite,
thus removing voids within the composite,19
      3.2.12.5  Curing.  Curing is the process of changing the resin into a
solid material so that  the composite part holds its shape.  This  is
accomplished by heating the lay-up assembly  in order to initiate  a
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polymerization reaction within the resin.   Once the reaction is complete, the
resin solidifies and bonds the layers of composite materials together.
      The curing process is typically performed in an autoclave (a pressurized
oven), with the composite lay-up enclosed in a bag so that a vacuum can be
applied.  The vacuum removes air and volatilized components of the resin from
within the composite structure which may otherwise be trapped and create
voids.  Key parameters for curing are time, pressure, vacuum, temperature, and
heating and cooling rates.20
      3.2.12.6  Break-Out.  Break-out is the removal of the composite
materials from the molds or curing fixtures (includes the application of
release agents prior to filling the mold).
3.2.13  Testing
      A wide variety of tests are performed by the aerospace industry to
verify that parts meet manufacturing specifications.  Leak tests are performed
on assemblies such as wing fuel tanks.  These parts are filled with an aqueous
solution or a gas to check seams and seals.  Dye penetrant is used following
chemical milling and other operations to check for cracks, flaws, and
fractures.  Many different kinds of penetrants, fluids, dyes, and etchants can
be applied to the surface of metal parts to aid in the detection of defects.
Hydraulic and fuel system checks are other typical testing operations.  Weight
checks are performed to verify the balance of certain structures, such as
propeller blades and vertical tail rudders.  Critical areas on the assembled
components are checked for flaws, imperfections, and proper alignment of parts
by X-ray.
3.3   UNCONTROLLED EMISSIONS
      The thirteen processes presented in Section 3.2 are intended to
encompass all HAP emitting processes involved in aerospace manufacturing and
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rework operations.  Emissions data for each of these processes were obtained
through Section 114 and site visit questionnaires.  The total  uncontrolled
emissions of HAPs for each process, as reported in the questionnaires, are
presented in Table 3-2.  Sections 3.3.1 to 3.3.4 present the source of
emissions and typical HAPs emitted from each process being considered in the
rule.
      Six non-coating related operations -- materials receiving; machining and
mechanical processing; chemical milling, metal finishing, and
electrodeposition; heat treating; composite processing; and testing -- and for
four coating-related operations -- adhesives; adhesive bonding primers;
sealants; and specialty coatings listed in Section 3.2 were found to
contribute negligible amounts to the overall uncontrolled emissions.  The six
non-coating related operations were found to account for less than 1 percent
of the total organic HAP emissions from aerospace facilities.  The four
      •
coating-related operations will be covered under the aerospace CTG with VOC
content limits.  These processes will not be discussed in this section, and
will not be considered further in the development of model plants or baseline
emissions presented in Chapter 6.
      All emission data presented in Sections 3.3.1 to 3.3.4 represent only
the facilities surveyed through the Section 114 and site visit questionnaires
(see Section 6.1 for a listing of these facilities).  The emission values in
this section, therefore, are not intended to represent nationwide values for
the industry as a whole.  Nationwide HAP emissions are presented in Section
6.2.
3.3.1  Maskant Application
      HAP emissions are associated with solvent evaporation during maskant
application and drying.  Maskants generally contain high levels [greater than
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              TABLE 3-2
TOTAL ANNUAL HAP EMISSIONS BY PROCESS
 AS  REPORTED  IN  THE  SECTION  114 AND
      SITE VISIT QUESTIONNAIRES
Process
Materials Receiving
Machining and Mechanical Processing
Maskant Application
Chemical Milling
Heat Treating
Sealants
Adhesive Bonding - Primers
- Adhesives
Cleaning
Metal Finishing
Coating Application - Primers
- Topcoats
- Specialty
Coating Removal (Depainting)
Electrodeposition
Composites Processing
Testing
Emissions
(Mg/year)
4
19
594
6
0.08
689
256
423
4855
20
715
639
473
1249
0.4
92
0.9
Emissions
(tons/year)
5
21
654
7
0.09
758
282
465
5341
22
787
703
520
1374
0.4
101
1
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700 grams VOC/liter (5.8 pounds VOC/gallon)] of VOC or HAP solvents such as
perchloroethylene or a to!uene/xylene mixture.
      The annual uncontrolled HAP emissions were 594 Mg (654 tons).  Maskant
applied by spray application methods are typically performed within a spray
booth, allowing for collection of the emissions and subsequent routing to a
control device.  Maskant applied by dip tank methods typically result in
fugitive emissions.  However, one large military/OEM facility has demonstrated
an enclosure for dip tank application in order to contain the HAP emissions.
3.3.2  Cleaning
      HAP emissions from cleaning operations occur from the evaporation of
cleaning solvents during the cleaning process, including evaporation of the
solvent from open containers.  Emissions also occur from the solvent-soaked
rags.  Cleaning solvent emissions occur from nearly every aerospace
manufacturing and rework operation and typically account for the largest
single portion of a facility's emissions.
      HAPs typically used in cleaning processes are methyl ethyl ketone,
methylene chloride, 1,1,1-trichloroethane, toluene, xylene, methyl isobutyl
ketone, and glycol ethers.  Total annual uncontrolled HAP emissions was 4,855
Mg (5,341 tons).  Since cleaning solvents are used so extensively throughout
the manufacturing and rework processes, emissions are typically fugitive and
difficult to collect to any appreciable degree.
3.3.3  Coating Application
      Most aerospace coatings used at the present time contain a mixture of
organic solvents.  HAP emissions from coating application occur from the
evaporation of the organic solvents during mixing, application, and drying-
Emissions of metal compounds (e.g., chromium and cadmium compounds) also occur
from overspray which is exhausted from spray booths or paint spray hangars.
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      HAPs typically used in coating application operations are 1,1,1-
trichloroethane, methyl ethyl ketone, toluene,  methyl isobutyl ketone, and
glycol ethers.   Total annual uncontrolled coating ^missions were 715 Mg (787
tons) for primers, 639 Mg (703 tons) for topcoats, and 473 Mg (520 tons) for
specialty coatings.  The majority of the coating application for parts and
subassemblies occurs in spray booths, allowing  for the collection of HAP
emissions.
3.3.4  Coating Removal (Depaintinq)
      Emissions from coating removal operations occur from evaporation of the
solvent in the stripping solutions.  The amount of emissions from the process
is directly related to the surface area being stripped, the type and thickness
of coating to be removed, and the effectiveness of the stripper.
      HAPs typically used in the coating removal process are methylene
chloride, toluene, xylene, and glycol ethers.  Total annual uncontrolled HAP
emissions were 1,249 Mg (1,374 tons).  The majority of emissions occur from
stripping the outer surface of aircraft in large hangars and are fugitive in
nature.
3.4   EXISTING STATE REGULATIONS
      The proposed rule represents the EPA's first comprehensive regulation of
the aerospace manufacturing and rework industry.  No Control Technology
Guidelines (CTG) or new source performance standards (NSPS) have been
promulgated specifically for this industry.  However, the surface coating of
miscellaneous metal parts and products CTG was  intended to reduce emissions of
VOCs from the coating of aerospace components under major group Standard
Industrial Classification (SIC) Code 37.
      The aerospace industry has been regulated primarily by State and local
rules.  California has the most comprehensive rules, such as South Coast Air
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Quality Management District Rule 1124.  This rule, which contains many
technology-forcing provisions, is used as the model for many other districts
in California, as well as other states.  Several states have only minimal
rules for the aerospace industry and several rely on the miscellaneous metal
parts and products (MMP&P) CTG.  The remaining states have no aerospace
specific rules, due primarily to there being few aerospace facilities within
the ozone nonattainment areas in these states.
      Eight States have adopted regulations specifically for the control of
emissions from aerospace manufacturing and rework operations.  Eight other
States apply the MMP&P CTG limits, with or without exemptions for specialty
aerospace coatings.  The regulations for these 16 States as well as the MMP&P
CTG limits are discussed below.  Additionally, five air toxics rules are
presented as example regulations.
      Table 3-3 presents the VOC limits extracted from the Miscellaneous Metal
Parts and Products CTG.21
3.4.1  California
      The State of California has been aggressive in developing and adopting
regulations for the control of air emissions.  Many local districts have
written their own aerospace specific regulations.  Three of these districts,
South Coast Air Quality Management District (AQMD), San Diego County Air
Pollution Control District (APCD), and Bay Area AQMD developed rules that were
subsequently approved by the EPA as part of the State Implementation Plan
(SIP).  These districts have developed more current rules that are not yet EPA
approved.  SIP approved regulations for the Bay Area AQMD, the San Diego
County APCD, and the South Coast AQMD are given in Section 3.4.1.1.  The rules
for these three districts are very similar.  The other districts in California
usually base their regulations on the existing, approved rules; therefore,
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                                TABLE 3-3

          MISCELLANEOUS METAL PARTS AND PRODUCTS CTG VOC LIMITS
Coating
Clear Coating
Air or forced air dried items, parts
too large or too heavy for practical
size ovens and/or sensitive heat
requirements, parts to which heat
sensitive materials are attached,
equipment assembled prior to top
coating for specific performance or
quality standards
Frequent color change and/or large
number of colors applied, or first
coat on untreated ferrous substrate
Outdoor or harsh exposure or extreme
performance characteristics
No or infrequent color change, or
small number of colors applied
Powder coatings
Other
VOC Limit
(grams/liter)
less water8
520
420
360
420
50
360
Negligibly photochemically reactive compounds are to be treated as if they
are water.
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most regional rules will not differ significantly from the first three.  A
detailed account of the primary California regional regulations for aerospace
industry  emissions is presented in Sections 3.4.1.2 through 3.4.1.6.  These
are the current regulations for each district and have not been approved by
the EPA.  Other districts, such as Sacramento Metropolitan AQMD, are currently
developing aerospace coating regulations.
      3.4.1.1  SIP Approved Aerospace Coating Rule Requirements.22   Table 3-4
presents the SIP approved regulations for the Bay Area AQMD, the San Diego
County APCD, and the South Coast AQMD.  Additionally, the Bay Area AQMD and
the San Diego County APCD allow provisions for facilities to operate under
alternative emission control plans (AECPs).  The AECPs must be approved by the
district's Air Pollution Control Officer.  Also, the AECPs emissions, on a
daily weighted average, must be no greater than would result if the processes
were under compliance with the rules.  Daily recordkeeping is required in the
Bay Area AQMD and the San Diego County APCD if a facility is operating under
an alternative emission control plan.  In the South Coast AQMD, daily coating
and solvent usage records are maintained at all facilities.
      3.4.1.2  South Coast Air Quality Management District.23   The  South  Coast
Air Quality Management District's rule has been the basis for many other
aerospace rules in the country.  For facilities emitting 20 pounds of VOC per
day or more, the VOC limits for coatings are presented in Table 3-5.  These
VOC limits may be achieved through the use of control equipment.  This control
equipment must reduce emissions from an emission collection system by at least
95 percent by weight, or the output of the air pollution control device must
be less than 50 parts per million (ppm) calculated as carbon with no dilution.
Additionally, the system must have a collection efficiency of at least 90
percent by weight of the emissions generated by the sources of emissions.
                                     3-25

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                                  TABLE 3-4
             VOC CONTENT REQUIREMENTS (grams/liter) IN SIP RULES
Coating Type
Primers
Topcoats
Adhesive Bonding Primer
Electromagnetic Radiation
Effect Coatings
Flight Test Coating
Fuel Tank Coating
Maskant
Pretreatment Coatings
Temporary Protective Coating
All Other Coatings
Stripper
BAAQMD
350
600
600
600
600
600
600a
600
250
600
400b
SDAPCD
350
600
600
600
600
600
600a
600
250
600
400b
SCAQMD
350
600
600
600
640
600
600a
600
250
600
400b
EXEMPTIONS IN SIP RULES
Low Usage Area
Low Usage Facility
Low Usage Coatingd
<20 Ib/day c

200 gal/yr
<1 gal/day
<50 gal/yr
<20 gal/yr e
<20 Ib/day

<20 gal/yr
SOLVENT CONTROL REQUIREMENTS IN SIP RULES
Spray Equipment Cleanup
Surface Preparation and
Clean-up
Closed Containers for:
Fresh Solvent
Spent Solvent
Solvent Rags
n/a
n/a

yesh
yesh
yes
20 mmHgf
45 mmHg9

no
no
yes
77.6 mmHgf
77.6 mmHg9

noi
no1
yes
  Or 85 percent control.
° Or vapor pressure less  than 10.0 mmHg at 20°C (68°F).
c Applies to each coating line.
  Applies to separate formulations.
e Provided that no more than 50  gallons total  of low usage coatings are
  applied at the facility annually.
f And at 20°C (68°F)  and  85 percent control.
3 At 20°C (68°F).
h Required by Bay Area AQMD Rule 8-1.
1 For cleanup of spray equipment, the facility must either collect VOC in a
  container and properly dispose of VOC, or disassemble  and clean equipment in
  a vat that is closed when not  in use, or use solvents  with less than 200 g/1
  of VOC.
                                     3-26

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                       TABLE 3-5
SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT VOC LIMITS9
Coating
Primer
Topcoat
Pretreatment Coating
Adhesion Promoter
Adhesive Bonding Primer
Cured at 250°F or below
Cured above 250° F
Flight-Test Coating
Used on Missiles or
Single Use Target Craft
All Other
Fuel -Tank Coating
Fuel -Tank Adhesive
Electric- or Radiation-Effect
Coating
Touch-up, Line-Sealer Maskants
Photolithographic Maskant
Temporary Protective Coating
Space-Vehicle Coatings
Electrostatic Discharge
Protection Coating
Other Space-Vehicle
Coatings
Adhesives
Wing Coating
Impact-Resistant Coating
High-Temperature Coating
VOC Limit
(grams/liter)
less water and exempt compounds
Limit"
350
600
780
850
850
1030
420
840
720
620
800
1200
850
250
800
1000
800
750
600
850
7/1/91
350
420
780
850
850
1030
420
840
720
630
800
750
850
250
800
1000
800
750
600
850
1/1/92
350
420
780
850
850
1030
420
840
720
620
800
750
850
250
800
1000
800
750
600
850
1/1/93
350
420
780
850
250C
250C
420
840
420
620
800
750
850
250
800
1000
800
750
600
850
1/1/94
350
420
780
850
250C
250C
420
840
420
620
800
750
850
250
800
1000
800
420
420
850
                         3-27

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TABLE 3-5 (Continued)
Coating
Antichafe Coating
Rain Erosion-Resistant Coating
Fire-Resistant Coating
Civilian
Military
Conformal Coating
Sealant
Adhesives
Non-Structural
Structural
Autoclavable
Non-Autoclavable
Optical Anti -Reflective
Coating
Wire Coatings
Electronic Wire Coating
Anti-Wicking
Pre-Bonding Etchant
Phosphate Ester
Resistant Ink
Metal ized Epoxy Coating
Clear Topcoat
Scale Inhibitor
Primer Compatible with Rain
Erosion-Resistant Coating
Self-Priming Topcoat
VOC Limit
(grams/liter)
less water and exempt compounds
Limitb
600
800

650
970
750
850

850

850
850
700

725
825
900
925
700
750
880
850
600
7/1/91
600
800

650
970
750
850

850

50
850
700

725
825
900
925
700
750
880
850
600
1/1/92
600
800

650
970
750
600

250

50
850
700

725
825
900
925
700
750
880
850
420
1/1/93
600
800

650
970
750
600

250

50
850
700

420
420
420
925
700
520
880
850
420
1/1/94
600
420

650
970
750
600

250

50
850
700

420
420
420
925
700
520
880
850
420
         3-28

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                            TABLE 3-5  (Concluded)
Coating
Maskant
Chemical Processing
Chemical Milling
Solid Film Lubricant
Fastener Installation
Fastener Lubricative
Non-Fastener Lubricative
Fastener Sealant
Dry Lubricative Material
Fastener Lubricative
Non-Fastener Lubricative
Barrier Coating
VOC Limit
(grams/liter)
less water and exempt compounds
Limit"
1200
1200
880
880
880
675
880
880
790
7/1/91
1200
1200
880
880
880
675
880
880
790
1/1/92
250
1200
880
880
880
675
250
880
790
1/1/93
250
250
880
250
880
675
250
880
420
1/1/94
250
250
880
250
880
675
250
880
420
a Limits apply to facilities emitting more than 20 Ibs VOC/day.

b Limits are established at the time of rule promulgation.   Subsequent dates
  define effective dates for stricter limits.

c Effective dates for the lower limits have been delayed until  1/1/95.
                                     3-29

-------
      Cleanup solvents must have a vapor pressure of 45 millimeters of mercury
(mmHg) or less at 20°C (68°F) and must contain 200 grams VOC/liter (1.6 pounds
VOC/gallon) or less.   Closed containers must be used for the storage and
disposal of cleanup materials.  Application equipment must also be cleaned in
an enclosed container.  Strippers must contain less than 300 grams VOC/liter
(2.5 pounds VOC/gallon) and have a vapor pressure of 9.5 mmHg or less at 20°C
(68°F).  Approved application methods are electrostatic application, flow
coat, roll coat, dip coat, high volume low pressure (HVLP) spray, hand
application methods,  or approved alternatives.  Coatings with separate
formulations used at less than 20 gallons per year are exempt from the
regulation limits.  Additionally, 1,1,1-trichloroethane, methylene chloride,
and trichlorotrifluoroethane are exempt.
      3.4.1.3  San Diego County Air Pollution Control District.24  The San
Diego County Air Pollution Control District rule is similar to the South Coast
AQMD rule.  The VOC limits for coatings are presented in Table 3-6.
      A company may reduce emissions from maskants by 85 percent or more in
lieu of meeting the coating content limit.  Surface preparation or cleanup
solvents must have a vapor pressure of less than 40 mmHg at 20°C (68°F), and
strippers must contain 400 grams VOC/liter (3.3 pounds VOC/gallon) or less and
have a vapor pressure of 9.5 mmHg or less at 20°C (68°F).  A facility must
control at least 85 percent of VOC emissions from spray equipment cleanup
operations and use closed containers for storage of solvent-laden materials.
      Exemptions include low usage coatings with separate formulations used at
less than 20 gallons per year per coating.  The total of low usage coatings
must be less than 50 gallons per year.  Other exemptions are: stripper and
methyl ethyl ketone (MEK) used solely to clean residue from components prior
to painting; the use of 1,1,1-trichloroethane, trichlorotrifluoroethane, and
                                     3-30

-------
                        TABLE 3-6
SAN DIEGO COUNTY AIR POLLUTION CONTROL DISTRICT VOC LIMITS
Coating
Primer (Except Adhesive
Bonding)
Maskant for Chemical
Processing
Temporary Protection
Coating
Space Vehicle:
Thermocontrol
Topcoat
Pretreatment Coating
Adhesive Bonding Primer
Flight Test Coating
Fuel Tank Coating
Electric- Effect Coating
All Other Coatings
VOC Limit
(grams/liter)
less water and
exempt compounds
350
250
250
600
420
780
850
840
650
800
600
                           3-31

-------
methylene chloride; a defined area,  spray paint booth,  or room using less than
1 gallon per day; and a stationary source using 50 gallons or less per year.
      3.4.1.4  Bay Area Air Quality Management District.25  The Bay Area Air
Quality Management District's rule provides a coating breakdown similar to the
South Coast AQMD and the San Diego APCD rules.  Facilities emitting 15 pounds
or less of VOC per day are exempt from this rule.   For facilities emitting
greater than 15 pounds of VOC per day, the VOC limits for coatings are listed
in Table 3-7.  These VOC limits apply unless emissions are controlled to an
equivalent level by air pollution abatement equipment with an abatement device
efficiency of 85 percent or more.  Strippers must contain less than 400
grams/liter (3.3 pounds/gallon) of precursor organic compounds or have a vapor
pressure of less than 10 mmHg at actual usage temperature.  Maskants must
contain less than 600 grams VOC/liter (5.0 pounds VOC/gallon), or the
emissions from maskant operations must be reduced by 85 percent.
      A facility must also control at least 85 percent of VOC emissions from
spray equipment cleanup operations and use closed containers for storage of
solvent-laden materials.
      Exemptions include the fabrication of electronic components including,
but not limited to, microprocessors, circuit boards, control  systems, and
instrumentation; tank type strippers employing a sealing fluid of 4 inches or
greater in depth and which consists of water or a fluid with a vapor pressure
of less than 10 mmHg at actual usage temperature; and high temperature curing
adhesive bonding primers which cure at temperatures greater than 325*F.   Other
exemptions are low usage coatings, which are coatings with separate
formulations used in volumes of 20 gallons or less per year.   The total of low
usage coatings must be 250 gallons or less per year.
                                     3-32

-------
                     TABLE 3-7
BAY AREA AIR QUALITY MANAGEMENT DISTRICT VOC LIMITS8
Coating
Primers (Except Adhesive
Bonding)
Adhesive Bonding Primer
Interior Topcoat
Electric- or Radiation-
Effect Coating
Extreme Performance
Interior Topcoat
Fire Insulating Coating
Fuel Tank Coating
High Temperature Coating
Sealant
Self-Priming Topcoat
Topcoat
Pretreatment Wash Primer
Sealant Bonding Primer
Temporary Protective
Coating
VOC Limit
(grams/liter)
less water and
exempt compounds
350
850
340
800
420
600
720
720
600
420
420
420
720
250
 8 Applies  to  facilities  emitting  >15  Ibs  VOC/day.
                        3-33

-------
      Coatings used in the aerospace industry that are subject to other non-
aerospace rules are the following:  paper-fabric film coatings (Bay Area
Regulation 3, Rule 4), adhesives (Bay Area Regulation 8, Rule 4), aerosol  can
coatings (Bay Area Regulation 8, Rule 49), stencil coatings (Bay Area
Regulation 8, Rule 4), solid film lubricants (Bay Area Regulation 8, Rule 4),
test panel coatings (Bay Area Regulation 8,  Rule 4),  and satellite coatings
(Bay Area Regulation 8, Rule 4).
      3.4.1.5  Ventura County Air Pollution  Control  District.26   The  Ventura
County Air Pollution Control District rule's reactive organic compound (ROC)
limits are shown in Table 3-8.  As with the  South Coast rule, compliance with
the ROC limits may be achieved through the use of control equipment.  This
control equipment must reduce emissions by at least 95 percent and must have a
capture efficiency of at least 90 percent.
      Cleanup solvents must have a vapor pressure of 45 mmHg or less at 20°C
(68°F) and must contain 200 grams VOC/liter (1.7 pounds VOC/gallon) or less.
Closed containers must be used for the storage and disposal of cleanup
materials.  Application equipment must also  be cleaned in an enclosed
container.  Strippers must contain less than 300 grams VOC/liter (2.5 pounds
VOC/gallon) and have a vapor pressure of 9.5 mmHg or less at 20°C (68°F).
      Approved application methods are electrostatic application, flow coat,
dip coat, HVLP spray, hand application methods, or approved alternatives with
a transfer efficiency of 65 percent or greater.
      Exemptions include stationary sources  that release less than 3 pounds of
ROC per day and 200 pounds or less per year from coatings, thinners, or any
other solvent containing materials associated with coating operations.  The
Ventura rule exemptions also  include low usage coatings.  A low  usage coating
is any coating that is used less than 20 gallons per year or any adhesive that
                                     3-34

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                         TABLE 3-8
VENTURA COUNTY AIR QUALITY MANAGEMENT DISTRICT ROCa LIMITS
Coating
Adhesion Promoter
Adhesives
Non-Structural
Structural
Autoclavable
Nonautoclavable
Adhesive Bonding Primers
Antichafe Coatings
Barrier Coatings
Clear Topcoat
Conformal Coating
Dry Lubricative Materials
Fastener Manufacturing
Nonfastener
Manufacturing
El ectri c/Radi ati on
Effect Coatings
Fastener Sealants
Fire Resistant Coatings
Civilian (Interior)
Flight Test Coatings Used on
Missiles or Single-Use Target
Craft
All Others
Fuel Tank Coatings
Fuel Tanks Adhesives
High Temperature Coating
ROC Limit"
(grams/liter)
less water and exempt compounds
7/1/88






850






880

800



600
600
720


1/22/91
850

850

850
850
850
600
790
750
900

880
880

880


650
600
600
720
620
850
1/1/92
850

250

50
850
780
600
790
750
750

250
880

880
675

650
420
600
650
620
850
1/1/93
850

250

50
850
780
600
420
520
750

250
880

880
675

650
420
600
650
520
850
1/1/94
850

250

50
850
780
600
420
520
750

250
880

880
675

650
420
600
420
620
850
                           3-35

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TABLE 3-8 (Continued)
Coating
Impact Resistant Coating
Maskants - Chemical Milling
Optical Anti -Reflective
Coating
Pretreatment Coatings
Primers Not Resistant To
Phosphate Esters
Phosphate Ester-Resistant
Primers
Rain Erosion-Resistant
Coating
Scale Inhibitor
Sealant
Solid Film Lubricants
Fastener Manufacturing
Solid Film Lubricants
Fastener Installation
Nonfastener
Manufacturing
Space Vehicle Coatings
Electrostatic Discharge
Protection
Other Space Vehicle
Coatings
Adhesives
Temporary Protective Coatings
Topcoats
Self-Priming Topcoats
ROC Limit
(grams/liter)
less water and exempt compounds
7/1/88



780
350
650




880

250
600

1/22/91
600
1200
700
780
350
650
800
880
850
880
880
800
1000
800
250
600
600
1/1/92
600
1200
700
780
350
350
800
880
600
880
880
880
880
1000
800
250
420
420
1/1/93
600
1200
700
780
350
350
800
880
600
250
880
880
800
1000
800
250
420
420
1/1/94
420
250
700
780
350
350
420
880
600
250
800
880
800
1000
800
250
420
420
         3-36

-------
                           TABLE  3-8  (Concluded)
Coating
Wing Coating
Wire Coatings
Electronic
Anti-Wicking
Pre-Bonding Etching
Phosphate Ester
Resistant Ink
ROC Limit
(grams/liter)
less water and exempt compounds
7/1/88






1/22/91
750

725
825
900
925
1/1/92
750

725
825
900
925
1/1/93
750

420
420
420
925
1/1/94
420

420
420
420
925
ROC = reactive organic compounds

Blank spaces indicate specific coatings are exempt until  a subsequent date
defines the effective limit.
                                   3-37

-------
is used less than 10 gallons per year.   The total  volume of low usage coatings
for one year excluding adhesives must be less than 200 gallons.   There is no
stated total volume of low usage adhesives.  Aerosol  can coatings and coatings
with a ROC content of less than 20 grams/liter (0.17  pounds/gallon)  are also
exempt.
      3.4.1.6  Imperial County Air Pollution Control  District.27  The  Imperial
County Air Pollution Control District's rule is also  similar to the  South
Coast rule.  The VOC limits are listed in Table 3-9.   Control  devices may be
used to achieve the VOC limits.  These devices must have an abatement device
efficiency of at least 90 percent and must control the emissions to  an
equivalent VOC level.  The control systems must be designed, operated, and
maintained to maximize the collection efficiency.   Facilities must submit a
petition for any specialty coating and low usage coating exemptions.
3.4.2  Alabama28
                                •
      The Jefferson County, Alabama, aerospace regulation applies to
facilities emitting 100 tons or greater of VOC per year and to coatings used
in volumes of 20 gallons or greater per year.  Facilities must use air-
assisted airless application methods or those with an equivalent transfer
efficiency.  Primers must contain 350 grams VOC/liter (3.0 pounds VOC/gallon)
or less.  However, if the primer is used on an aircraft that is using
phosphate ester as a hydraulic fluid, then the primer may contain up to 650
grams VOC/liter (5.4 pounds VOC/gallon) if the facility owner is in  a
compliance program to enable the 350 grams VOC/liter (3.0 pounds VOC/gallon)
or less standard to be attained.  The compliance program can consist of any of
the following:  add-on control equipment, replacement process equipment, low
solvent content coating, or equipment modification.  Surface preparation and
cleanup materials must have a  vapor pressure of less than 45 mmHg at 20°C
                                     3-38

-------
                                TABLE 3-9

        IMPERIAL COUNTY AIR POLLUTION CONTROL DISTRICT VOC LIMITS
Coating
Primer
Topcoat
Pretreatment
Adhesive Bonding
Flight Test
Fuel Tank
Radiation or Electrical Effect
Maskant
Solid-Film Lubricant
Temporary/Protect! ve
High Temperature
Ablative
Space-Vehicle
Electrostatic
Thermocontrol
Other
Strippers
Clean-Up Solvent
VOC Limits
(grams/liter)
less water and
exempt compounds
Limit3
350
420
780
720
600
600
420
600
800
250
800
600
800
600
1000
400

1/92
350
420
420
600
420
420
420
600
600
250
420
600
600
600
400

Vapor
Pressure
Limits
(mmHg)













9.5b
45b
Limits established at the time of the rule promulgation.
At 20°C (68°F).
                                   3-39

-------
(68°F) and contain 15 percent or less by weight of VOC or the facility must
collect and dispose of 85 percent or more of the VOC.   Chemical  strippers must
have a vapor pressure of 9.5 mmHg or less at 20°C (68°F)  and contain 400 grams
VOC/liter (3.3 pounds VOC/gallon) or less.  Closed containers must be used for
the disposal of VOC-containing materials.  The MMP&P CTG  limits  apply to any
aerospace facilities in the rest of the State.
3.4.3  Connecticut29
      The State of Connecticut does not have a regulation specific to the
aerospace industry.  Instead, aerospace facilities are subject to rules for
several sources of emissions.  Connecticut has established reasonably
available control technology (RACT) for flow coaters as a carbon
adsorption/solvent recovery system.  Further, all facilities are required to
begin the conversion to low VOC coatings.  The schedule of compliance is
determined on a case-by-case basis.  The use of low solvent coatings includes
the alternative option of adsorption or the equivalent.  These regulations
only apply to facilities with actual VOC emissions of 100 tons or more per
year and individual pieces of equipment with VOC emissions of 40 pounds or
more per day.
3.4.4  Oklahoma30
      The Oklahoma MMP&P regulation applies to facilities emitting 100 pounds
or more per 24 hours.  The VOC coating limits for general coatings are shown
in Table 3-10.
      The Oklahoma limits apply unless emissions that were uncontrolled prior
to the rule promulgation are reduced by 90 percent by incineration, or reduced
by 85 percent by adsorption, or the equivalent.  Facilities are also limited
to releasing a maximum of 3,000 pounds of organic material per day and 450
pounds or less per hour.  Exemptions to these limits exist if the discharge is
                                     3-40

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                                  TABLE 3-10
                          OKLAHOMA MMP&P VOC LIMITS
Coating
Alkyd Primer
Vinyls
NC Lacquers
Acrylics
Epoxies
Maintenance Finishes
Custom Product Finishes
VOC Limit
(grams/liter)
less water and
exempt compounds
575
720
770
720
575
575
780
reduced by 85 percent or best available control  technology (BACT) is attained
by the facility.  Owners or operators may develop a plant-wide emission plan
which must be approved by the Commissioner.  BACT is determined for specific
sites by the Commissioner.
      Cleanup solvents must be maintained in a closed container when not in
use.  Closed containers must also be used for the disposal of cloth or other
materials containing cleanup solvents.  Solvents used to clean application
equipment must be collected.  Exempt coatings are individual  coating
formulations that total less than 55 gallons per year per facility.
3.4.5  Texas31
      The Texas MMP&P regulation is pending EPA approval.  The daily weighted
average VOC emissions of coating as applied are listed in Table 3-11.
Interior coating operations fall under the MMP&P CTG.
                                     3-41

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                                  TABLE 3-11
                            TEXAS MMP&P VOC LIMITS
Coating
Exterior Primer
Clear Coat
Extreme Performance
Other Coatings
VOC Limit
(grams/liter)
less water and
exempt compounds
420
515
420
360
3.4.6  Missouri32
      The Missouri regulation for aerospace facilities applies to the South
St. Louis area and sets the VOC emission limits listed in Table 3-12.
                                  TABLE 3-12
                             MISSOURI  VOC  LIMITS
Coating
Primer
Topcoat
Maskant
VOC Limit
(grams/liter)
less water and
exempt compounds
720
600
120
      Interior refinishing of airplanes is exempt as well  as facilities that
release less than 2.5 tons per year of VOC.  Exempt coatings are adhesion
promoters, adhesive bonding primers, flight test coatings, space vehicle
coatings, fuel tank coatings, and dry film lubricants.
3.4.7  Washington33
      The Puget Sound Air Pollution Control Agency (APCA)  regulation, which
covers King, Kitsa, Pierce, and Snohomism counties, regulates VOC emissions
from aerospace facilities emitting 40 pounds or more of VOC per day on an
                                     3-42

-------
annual average.  Aerospace facilities in the rest of the State are subject to
the MMP&P rule.  The Puget Sound APCAs VOC limits for the regulated coatings
are listed in Table 3-13.
                                  TABLE 3-13
                    WASHINGTON  AEROSPACE COATING  VOC  LIMITS
Coating
Commercial Primer
Commercial Topcoat
Military Primer
Military Topcoat
Temporary Protective Covering
VOC Limit
(grams/liter)
less water and
exempt compounds
Limit8
650
600
350
420
250
1994
350
420
350
420
250
            a Limits established at the time of rule promulgation.

      Exempt coatings are maskants for chemical milling operations, adhesive
bonding primers, flight test coatings, space vehicle coatings, fuel tank
coatings, and any coating for which a reasonably available alternative does
not exist.  The VOC controls can also be achieved through vapor collection and
a disposal  system, or an approved equivalent.  Approved application equipment
are HVLP, electrostatic, flow coat, dip coat, brush coat, trowel  coat, hand-
held aerosol can, roll coat, electrodeposition, curtain coat, or  other
approved methods.  This rule does not apply to the application of touch-up
coatings, stencil coatings, wire markings, inks, and sheet mold compounds.
3.4.8  New  York34
      The New York regulation for aerospace facilities applies to the New York
City metropolitan area and sets the VOC emission limits listed in Table 3-14.
                                     3-43

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                                  TABLE 3-14
                             NEW YORK  VOC LIMITS
Coating
Primer
Topcoat
Maskant
VOC Limit
(grams/liter)
less water and
exempt compounds
350
612
612
      Exempt coatings are those utilized for pretreatment, adhesive bonding
primers, adhesion, sealing, flight testing, electric/radiation effects, space
vehicles, fuel tanks, and temporary mechanical  maskant/high temperature heat
treatment.  Also exempt are coatings that are applied manually with a brush or
an aerosol spray can.
3.4.9  Other States
      Table 3-15 presents the national areas that apply the MMP&P CTG limits.
                                  TABLE 3-15
                     AREAS  THAT  APPLY  THE  MMP&P CTG  LIMITS
AREAS
Washington
Pennsylvania
New Jersey
Wisconsin
Oregon
Delaware
Massachusetts
Colorado
Other States with no
aerospace rules
EXEMPTIONS
areas covered by specific aerospace rule
sources that emit < 50 tons VOC/year
exterior coating of aircraft
exterior coating of airplanes, specialized
coatings required by State or Federal
agencies
sources that emit < 15 Ibs VOC/day
no aerospace exemptions
sources that emit < 25 tons VOC/year
coating of aircraft,
division approved high performance coatings
no specific aerospace exemptions
                                     3-44

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3.4.10  Air Toxic Rules for Various States
      The aerospace industry is also affected by State air toxics rules.  Many
States have regulations applicable to process emissions that are not covered
by a specific State or Federal regulation.  Five State air toxics regulations
are discussed below as examples of typical regulations.
      3.4.10.1  Michigan.35  The  Michigan  Department  of Natural  Resources'  Air
Pollution Control General  Rules state that anyone building or modifying any
process or equipment that may emit a toxic air contaminant must apply for a
permit.  Additionally, any person applying for a permit shall not allow the
emission of any toxic air  contaminant in excess of each of the following:
      (1)   The maximum allowable emission rate based on the application of
            best available control technology for toxics (T-BACT).  The
            maximum allowable emission rate is 0.1 pound per hour or less for
            a carcinogen or 1.0 pound per hour or less for any other toxic air
            contaminant.
      (2)   The maximum allowable emission rate that results in a predicted
            maximum ambient impact that is more than the initial threshold
            screening level  (ITSL) (> 200 micrograms per cubic meter) or the
            initial risk screening level  (IRSL) (> 0.1 micrograms per cubic
            meter), or both.
      A commission will be established to determine, on a case-by-case basis,
whether the maximum allowable emission rate provides adequate protection of
human health or the environment.  This commission may determine a more
rigorous regulation limit.
      This regulation is not applicable to processes that are covered by
national emission standards.  Other exemptions include processes that are in
compliance with T-BACT or  lowest achievable emission rate (LAER) requirements
                                     3-45

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and processes with a predicted ambient impact for each toxic air contaminant
that is less than the IRSL and the ITSL.   The emissions of a carcinogen is
exempt from being in compliance with the  IRSL if the total allowable emissions
of the carcinogen from the proposed new or modified process and all existing
processes at the stationary source result in a predicted ambient impact less
than or equal to the secondary risk screening level.
      The initial and secondary risk screening levels for a carcinogen shall
be determined by any of the following:
      (1)   the State cancer risk assessment methodology;
      (2)   the EPA guidelines;
      (3)   any alternative methodology proven to be more appropriate.
      The predicted ambient impact of each toxic air contaminant shall be
determined using the maximum hourly emission rate.
      Permit system exemptions applicable to the aerospace industry are
vacuum-cleaning systems used for housekeeping, water blast-cleaning equipment,
furnaces, ovens, heaters, testing and inspection equipment, pilot processes,
small storage containers, and maintenance or repairs.  Other exempt processes
are the following if the emissions are only released into the general in-plant
environment:  surface treatment, pickling, acid dipping, cleaning, etching,
electropolishing, electrolytic stripping, or plating.  Additionally, an
adhesive coating line that has an application rate of less than 2 gallons per
day and releases emissions only into the in-plant environment is exempt.
      3.4.10.2  Ohio.36   The  Ohio  EPA  has  developed  a  guidance  policy for
permitting new sources of air toxics emissions into the atmosphere.
      Currently, the State of Ohio uses the following equation to determine
maximum acceptable ground level concentration (MAGLC):
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      MAGLC =     4 TLV
                    XY
where:
      X     =     operating hours per day of the source above 8 hr/day;
      Y     =     operating days per week above 5 days per week;
      TLV   =     Threshold Limit Values, published by the American Conference
                  of Governmental Industrial Hygienists.

      For 40 or less hours per week of plant operation, the MAGLC formula is
the following:
      MAGLC =     4 TLV
                    42

      The State is currently trying to pass a new policy document.  This
document includes a review of each specific compound to determine if it is
toxic air contaminant.37
      If the contaminant is carcinogenic, and emissions exceed the TLV, the
State plans to perform  a health impact/risk assessment study to determine the
maximum individual risk.  If this risk is greater than 1 x 10"5  per  toxicant
emitted (one incident of cancer per 100,000 persons exposed), the applicant
must reduce the emissions by application of BACT.  If the contaminant is not
carcinogenic, MAGLC is  used to determine acceptable concentrations.  The MAGLC
is to be modified and made more conservative as follows:
      MAGLC =     TLV
                  70
Sources covered by other Federal regulations are exempt.
      3.4.10.3  Connecticut.38   In  the State of  Connecticut,  no  stationary
source may emit any hazardous air pollutant in excess of the maximum allowable
stack concentration.  The maximum allowable stack concentration (MASC) is
determined as follows:
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      (1)   If the discharge point is 20 meters or less measured  vertically
            from the ground,
            MASC  =     0.885 HLV (X + 1.08V 0.64)1'56
                                    V
where:
            HLV   =     hazard limiting value found  in the regulation tables
            V     =     average actual flow rate  (cubic meters  per second)
            X     =     ten meters or the distance from the discharge point to
                        the closest pro'perty line, whichever  is greater
      (2)   If the discharge point is more than 20 meters:
           MASC = 0.885 HLV (X * 1.08V0"9 j1'58  exp [10.33 (H-20)2 (X * 1.08V0'84  )-1M ]
                                      V
where:
      H     =     height of discharge point (meters)
      X     =     ten meters or the distance from the discharge point to the
                  closest property line or 4.47 (H-20)1'28, whichever is
                  greater
      If a source exceeds MASC, BACT must be installed and used for the
applicable hazardous air pollutant.
      3.4.10.4  Kansas.39  The  Kansas Air Toxics Strategy is  a regulatory
screening mechanism to  control air toxics which are  not controlled by State or
Federal standards.  The strategy gives the State  the authority  to promulgate
air emission regulations and enforce those regulations through  inspections,
administrative orders,  and  injunctive orders.
      The strategy applies  a significant risk level  to the emissions of air
toxics from new or modified point sources during  normal working operation.
The significant risk level  for carcinogens is 1 x 10"6 (one incident  of cancer
per million persons exposed).  For non-carcinogens,  the  significant risk level
is a  fraction of the Threshold Limit Values  (TLV) published  by  the American
Conference of Governmental  Industrial Hygienists. The significant risk level
for long term  (chronic) exposure is  TLV/420  and the  significant risk-level  for
short term exposure  is  TLV/100.
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      All new or modified sources must apply for a State permit.  At this time
the source's emissions are identified and air toxic quantities are calculated.
The significant risk levels are calculated and an air quality computer model
is run to determine the ambient impact.  If the significance level is
exceeded, options for emission reductions are evaluated.  If the air toxic is
a carcinogen, BACT will be required.  If not, a risk management decision will
be made which reflects factors such as technical feasibility, costs, and
social and economic benefits.
      3.4.10.5  Washington.40  The  State  of  Washington's  controls  for  new
sources of toxic air pollutants affect all new sources in the aerospace
industry.  Exempt sources are containers, non-process fugitive emissions from
stationary sources, solvent metal cleaners, spray coating operations, and
abrasive blasting unless determined otherwise by the State.
      The owner of a new source must notify the State prior to construction
and file a notice of construction application for the proposed emission
source(s).  The facility must be in accord with Federal and State regulations.
Additionally, the facility must use T-BACT for emissions control for any toxic
air pollutants which are likely to increase and reasonably available control
technology for toxics  (T-RACT) for any toxic air pollutants which are likely
to remain the same or decrease.  A list of toxic air pollutants is given in
the regulation as Class A or Class B toxics.  Class A toxics are known and
probable carcinogens.  Class B toxics includes any substance that is not a
simple asphyxiant or nuisance particulate.  After review, the State will make
a final determination and may require an operation and maintenance plan to
assume continuous compliance.
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      Risk-based acceptable source impact levels for toxics can be calculated
by:
      Risk-based  =   Risk
                      URF
where:
      Risk  -  Cancer risk level (1 in 1,000,000);
      URF   =  Upper bound unit risk factor as published in the US EPA
               Integrated Risk Information System database or other
               appropriate sources.

      T-BACT is described in the regulation for specific sources.  The ones
that affect the aerospace industry are solvent metal cleaners and abrasive
blasting.
      T-BACT for solvent metal cleaners requires the use of covers for tank
lines,  closed containers for solvents, and component drainage into the tank
line.  T-BACT for abrasive blasting requires blasting within an enclosed space
to control particulates if possible and, if not, blasting outside with steel
shot and with protective tarps.
      An owner of a new source must also provide data to determine the
expected ambient impact.  Dispersion modeling is used to determine the affects
on human health and safety from potential carcinogenic and/or other toxic
effects.  A detailed analysis may be involved including such factors as
demographics, lexicological profiles of pollutants, and characterization of
outlet pathways.
      Finally, the State may approve the emissions even if the ambient
concentrations are likely to result in an increased cancer risk only if:  (1)
the proposed controls represent all known and reasonably available technology;
(2) prevention methods including recycling, chemical substitution, and efforts
to redesign process; and {3} emission bubbles and offsets are put in placa.
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3.5  REFERENCES
      1.    U.S. Department of Commerce, Bureau of the Census, County  Business
            Patterns 1988 and 1989.  March 1992.

      2.    U.S. Department of Transportation, Federal Aviation
            Administration, Advisory Circular, FAA Certificated Maintenance
            Agencies Directory. Appendix 1 and 2.  August 7,  1992.

      3.    Process descriptions were taken from various Section  114
            questionnaire responses from aerospace manufacturing  and rework
            facilities.

      4.    Air Pollution Engineering Manual - Second Edition AP-40,
            Environmental Protection Agency, Office of Air Quality  Planning
            and Standards, Research Triangle Park, NC  27711.  May  1973.
            p.801.

      5.    Reference 4.  p. 801.

      6.    Compliance Assistance  Program - Surface Coating Operations -
            Aerospace.  California Air Resources Board, Compliance  Division,
            July 1990.  p. 200-11.

      7.    Section 114 response from the Renton facility of  The  Boeing
            Company.

      8.    Chattopadhyay, Ashok K. and Mark R. Zentner, Aerospace  and
            Aircraft Coatings.  Federation Series on Coatings Technology.
            Philadelphia, PA, May  1990.  p. 11.

      9.    Reference 8.  p. 11.

      10.   Sax, N. Irving and Richard J. Lewis, editors, Hawlev's  Condensed
            Chemical Dictionary. Eleventh Edition.  New York, Van Nostrand
            Reinhold Company, Inc., 1987.  p. 917.

      11.   Lagedes, Daniel N., editor, McGraw-Hill Dictionary of Scientific
            and Technical Terms. Second Edition.  New York, McGraw-Hill,  Inc.,
            1978.

      12.   Glossary for Air Pollution Control of Industrial  Coating
            Operations. Second Edition.  EPA-450/3-83-013R, December 1983.

      13.   "Naval Aviation Depot, North Island Air Toxics Emission Inventory
            Report" (AB2588), Volume 3, p. 780.

      14.   McGraw-Hill Encyclopedia of Science and Technology. Volume 10,
            Seventh Edition.  New  York, McGraw-Hill,  Inc., 1992.  p. 391.

      15.   Weeton, John W., Dean  M. Peters, and Karyn L. Thomas, Engineer's
            Guide  to Composite Materials. American Society for Metals. Ohio,
            1987.  p.  14-10.
                                      3-51

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16.    Reference 15.  p.  14-4.

17.    Reference 11.

18.    Reference 14. Volume 14.   p. 42.

19.    Reference 15.  p.  14-5.

20.    Lee, Stuart M., editor,  International  Encyclopedia of Composites.
      Volume 3, New York, VCH  Publishers, 1990.   p.  123.

21.    Control of Volatile Organic Emissions  from Existing Stationary
      Sources.  Volume VI:  Surface Coating  of Miscellaneous Metal Parts
      and Products.  U.S. EPA,  Emission Standards and Engineering
      Division, Chemical  and Petroleum Branch, June 1978.

22.    Phase III Rule Effectiveness Study of the Aerospace Coating
      Industry.  EPA Region IX Air Resources Board FY89.  pp. 15 - 16.

23.    South Coast Air Quality  Management District, Aerospace Assembly
      and Component Manufacturing Operations, Rule 1124.  August 2,
      1991.

24.    Reference 6. pp. 300-1 -  300-12.

25.    Bay Area Air Quality Management District,  Organic Compounds -
      Regulation 8, Aerospace  Assembly and Component Coating Operations
      - Rule 29.  June 20, 1990.

26.    Ventura County Air Pollution Control District, Aerospace Assembly
      and Component Manufacturing Operations, Rule 74.13.  January 22,
      1991.

27.    Reference 6. pp. 300-1 - 300-12.

28.    Alabama Air Pollution Rules, Aerospace Assembly and Component
      Coatings Operation, 335-3-6-.46.  Environment Reporter.  September
      21, 1990.

29.    State Order 8015.   State of Connecticut, Department of
      Environmental Protection versus Sikorsky Aircraft Division of
      United Technologies Corporation, Attachment #1.  Final.  October
      25, 1989,

30.    Oklahoma Department of He.alth, Control of Emissions of Organic
      Solvents, Regulation 3.7.  Environment Reporter.  January 24,
      1990.

31.    Texas Regulation 5, Surface Coating Processes, 115.421 - 115.425,
      Environment Reporter.  December 21, 1990.

32.    Missouri Air Pollution Rules, Control  of Emissions from Industrial
      Surface Coating Operations, 10 CSR 10-5.330.  Environment
      Reporter.  March 30, 1990.


                               3-52

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33.   Washington Air Pollution Rules, Aerospace Component Coating
      Operations, Section 3.09.  July 15, 1990.

34.   Public Hearing Proposal Amendments to 6NYCRR Part 228, "Surface
      Coating Processes."  October 1992.  107 pp.

35.   Michigan Air Toxic Regulations, R336.1102 - R336.1285, Department
      of Natural Resources, Air Pollution Control Commission, General
      Rules Addendum.  April 17, 1992.

36.   Ohio Environmental Protection Agency, Division of Air Pollution
      Control Review of New Sources of Air Toxic Emissions, Option A.

37.   Ohio Environmental Protection Agency, Public Notice of "Review of
      New Sources of Air Toxic Emissions - Guidance Manual", Final
      Draft.  February, 1991.

38.   State of Connecticut Environmental Protection, "Hazardous Air
      Pollutants," Section 22a-174-29.  February, 1989.

39.   Kansas Air Toxics Strategy, The Bureau of Air Quality and
      Radiation Control: Kansas Department of Health and Environment.
      August 9, 1988.

40.   State of Washington, "Controls for New Sources of Toxic Air
      Pollutants," Chapter 173-460 WAC.  June 18, 1991.
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                  4.0  EMISSION CAPTURE AND CONTROL TECHNIQUES

      The principal techniques used by the aerospace industry to control HAP
emissions are preventative measures and control devices.  Preventative
measures are any action, product modification, process modification, or
equipment change designed to eliminate or reduce the generation of emissions.
Control devices do not prevent the generation of emissions, but rather capture
or destroy the emissions generated by a source.
      The most common preventative measures are usually the most desirable
method to reduce emissions since they eliminate or reduce the actual
              •
generation of pollutants.  Typically, the emission reduction is obtained using
less energy and producing less waste than using a control device to achieve
the same emission reductions.  Preventative measures used by the industry are:
(1) product substitutions where products that contain high levels of HAPs and
VOCs are replaced with products containing less HAPs and VOCs or that
eliminate the HAP or VOC content completely, such as non-HAP chemical
strippers for depainting; (2) product substitutions that reduce the amount of
the HAP- and VOC-containing product used, such as higher solids content
coatings; (3) equipment changes that result in emission reductions, such as
replacing conventional spray guns with high-volume low-pressure (HVLP) spray
guns; and (4) work practice standards, such as housekeeping.
      Control devices are typically used where product substitution and
equipment changes are not feasible or where the concentration of the exhaust
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stream is sufficiently high to warrant their use.   Control devices may destroy
the HAPs and VOCs, as with an incinerator,  or capture the HAPs and VOCs, as
with a carbon adsorber.  Often, the compounds captured by a control device can
be recovered for reuse.  Control devices in predominant use by the industry to
control organics are:  (1) carbon adsorbers, (2) incinerators, and
(3) ultraviolet oxidation.  Activated carbon fiber absorbents to concentrate
VOC emissions are frequently used in conjunction with incinerators, and
catalyst-coated filter medias are being used in spray booths to control low
VOC concentrations.  Control devices used by industry to control dry
particulates are:  (1) baghouses, (2) mechanical centrifugal separators, and
(3) dry filters; and control devices used to control wet particulates are:
(1) dry filters and (2) waterwash spray booths.
4.1  PREVENTIVE MEASURES
4.1.1  Product Substitution
    •
      HAP and VOC emissions may be controlled by replacing products containing
high concentrations of HAPs or VOCs with ones that have reduced or eliminated
HAPs or VOCs entirely.  Each individual facility must evaluate the ability of
the new product to maintain standards of quality and performance.  In
addition, the potential overall environmental benefit of the reformulated
products must be carefully evaluated.
      4.1.1.1  Coating Substitutions.  Product substitutions for coatings can
be generally classified as waterborne, higher solids, powder, and self-priming
topcoats.  Resin seal anodizing can also be considered an alternative for
coating application.  Each category is discussed below.
      4.1.1.1.1  Waterborne Coatings.  Waterborne coatings utilize a resin
system that is dispersible in water.  A portion of the organic solvent  is then
replaced with water.  The organic solvent may be 5 to 40 percent by weight of
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the waterbome coating as applied,  compared  to  a  conventional  organic  solvent-
based coating containing as much as 70  to  80 percent  by  weight solvent,  as
applied.   The use of solvent is to  aid  in  coating application,  wetting of
substrate surface,  viscosity control, and  pigment dispersion.1
      Waterbome coatings use water dispersible polymers or  a  suspension of
water and polymers.   In waterbome  coatings,  organic  polymers  (e.g., alkyds)
are made dispersible by giving them ionic  characteristics.   Some  of the  base
polymers for waterbome coatings are acrylics,  polyesters, urethanes,  and
epoxies.2
      In addition to the lower solvent  content, waterbome coatings have other
advantages over solvent-based coatings.  Less overspray  and  improved spray
transfer efficiency may be achieved with waterbome coatings than with
conventional coatings that utilize  solvents  with  a density less than that of
water.3  Additionally,  because of the reduced solvent content,  waterbome
coatings may be less toxic and present  a reduced  fire hazard.4
      Waterbome coatings have limitations such as requiring spray guns  with
specific materials of construction, protection  from freezing,  and better
control of temperature and humidity during application.5 In addition,
waterbome coatings generally require longer drying times, are more sensitive
to substrate cleanliness and composition,  may have shorter shelf  stability and
pot-life, and have lower salt spray resistance.6
      4.1.1.1.2  Higher Solids Coatings.   Higher  solids  coatings  are solvent-
based coating formulations that have been  modified to lower  the solvent-to-
sol ids ratio.  The coatings usually contain  50  to 65  percent by volume solids,
compared to conventional solvent-based  coatings that  may contain  up to 40
percent by volume solids.  The increased solids content  gives  greater  surface
area coverage per gallon of coating which  reduces the total  volume of  coating
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required.   Consequently,  solvent emissions  are also reduced when higher solids
coatings are used to apply the same volume  of solids as applied with a
conventional solvent-based coating.7
      Higher solids coatings generally have higher viscosities and longer
drying times than conventional solvent-based coatings.   Higher viscosity tends
to make spray application more difficult because it is  harder to control gloss
and film thickness, and may require the coating to be heated before
application.  Higher solids coatings typically are not  used as dip coatings
due to the difficulty in maintaining a uniform dispersion of solids in the dip
tank.8
      4.1.1.1.3  Powder Coatings.  Powder coatings are  a class of coatings
applied electrostatically in dry form and then baked to cure.  The coatings
consist of fine, dry particles of paint solids.  During the curing step, the
particles fuse to create a continuous film.  Use of powder coatings requires
that the substrate must be able to withstand the high temperatures [typically
greater than 121°C (250°F) and often greater than 177°C (350°F)] necessary to
cure the paint.  Therefore, most powder coatings are developed for steel
substrates which can accept the curing temperatures.9
      These coatings require resins that are solid at room temperature and
melt at higher temperatures.  The most common resins used in powder coatings
are epoxies and polyesters.10
      The major advantage of using powder coatings is greatly reduced solvent
emissions.  The lack of a solvent base also reduces fire hazard, toxicity, and
the make-up air requirements of the spray booth.11
      Powder coatings must be applied electrostatically, so they cannot be
used on non-conductive parts such as composites.  Other reported disadvantages
of powder coatings are the difficulty in obtaining a high quality appearance,
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production must be shut down for color changes, and the powder must remain dry
at all times prior to application.  Touch-up and rework is also difficult and
coating resistance to soil is reduced.  In addition, the high curing
temperatures of powder coatings precludes its use on temperature sensitive
substrates.12
      4.1.1.1.4  Self-priming Topcoats.  Self-priming topcoats eliminate the
need to apply a primer coat between the substrate and the topcoat.  The self-
priming topcoat has the adhesion and corrosion characteristics of a
conventional primer, and the environmental resistance and functional fluid
resistance of a conventional topcoat.  The required dried film thickness is
generally the same as a conventional primer and topcoat; therefore, solvent
emissions are reduced, particularly when the proper dried film thickness can
be achieved by a single coat.  These coatings also eliminate the need for
chrome-containing primers.13
      4.1.1.1.5  Resin Seal Anodizing.  A resin seal anodize process has been
developed by a large military/OEM facility that replaces the dichromate seal,
priming, and topcoat operation for many parts and assemblies.  In this
process, an aerospace component is immersed in a resin seal anodize bath that
contains 7 percent solids of a colloidal polyurethane resin.  An anodize film
develops on the surface of the part, and resin particles are deposited within
the anodize film to form a resin-rich surface.  The component has effectively
been anodized and sealed, eliminating the need for primer and topcoat
operations.14
      Parts processed with resin seal anodizing are lighter in weight since
primer and topcoat are not necessary.  This process also provides better
corrosion protection in some instances compared to conventional processes and
greatly reduces the HAP emissions and waste streams associated with the
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conventional processes.  According to the patent holding facility, the process
reduces emissions 20 to 30 percent over the conventional process of anodizing,
priming, and topcoating.  However, a tank line to hold the process must be
constructed, and the tanks must be large enough to hold the entire part.15
      4.1.1.2  Hand-Wipe Cleaner Substitutions.  Product substitutions for
hand-wipe cleaning that are prevalent in the aerospace industry can be
classified as aqueous, citrus-based, reduced HAP content, and non-chemical.
Each category is discussed below:
      4.1.1.2.1  Aqueous.  Aqueous cleaners contain water as the base
component rather than an organic solvent or mixture of solvents.  Other
components may include corrosion inhibitors, alkalinity builders, and organic
surfactants depending on the desired soil removal properties.16   Aqueous
cleaners have been used in non-critical areas where strict cleanliness
requirements do not have to be met, or where there are no confined spaces that
may trap residues of the cleaner.
      The advantages of using aqueous cleaning solvents include reducing HAP
emissions and possibly reducing waste streams.  Disadvantages are increased
production time due to slower evaporation rates, possible decreased
efficiency, and possible increase in wastewater treatment requirements.  In
addition, aqueous cleaners may not be applicable to all aerospace parts,
especially those components that have small confined spaces where the cleaner
residues cannot be adequately removed.17
      4.1.1.2.2  Citrus-based.  Citrus-based terpenes such as d-limonene are
the primary components in many alternative cleaning solutions.  While these
solutions have high VOC contents, their vapor pressure is very low leading to
reduced evaporation rates.  These cleaners have been found to be effective in
                                                                       4 o
most cleaning operations except for cleaning prior to adhesive bonding.
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Some disadvantages include possible worker sensitivity, VOC emissions, and
lack of rinseability in water.
      4.1.1.2.3  Reduced HAP Content.  Many cleaning solutions achieve a
reduction and, in some cases, a complete elimination of the HAP content by
substituting non-HAP components such as hydrocarbon or oxygenated hydrocarbon
mixtures, or bioenzymes mixtures.  These cleaning solutions differ from
aqueous cleaners in that they are not water-based.19
      4.1.1.2.4  Non-chemical.  Several aerospace facilities have demonstrated
the viability of using non-chemical methods such as dry media blasting for
cleaning operations.  These methods are typically used to remove dry, scale-
like deposits such as carbon residue on engine components.  Dry media blasting
can usually be used only on components that can withstand the force of
blasting without deformation.
      4.1.1.3  Depainting Stripper Substitutions.   Product substitutions for
strippers generally contain no methylene chloride,  no phenols, no chlorinated
solvents, no heavy metals, and no chromates.  The active components found in
these strippers may include formic acid, phosphoric acid, benzyl alcohol, and
ammonia.  Therefore, they typically have a low toxicity level, low vapor
pressure, and are not flammable.20  These strippers  can be used  in  existing
facilities with no modifications.21
4.1.2   Equipment Changes
      The aerospace industry has  implemented  several equipment changes that
directly reduce the level of HAP  emissions.   While  there are equipment changes
that effect emissions from every  process, the four  changes predominantly used
in  the  industry are high transfer efficiency  spray  guns, enclosed spray gun
cleaners, proportional paint mixers, and non-chemical  depainting methods.
Each of these equipment changes  are discussed below.
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      4.1.2.1  High Transfer Efficiency Spray Guns.   Emissions from spray
coating operations can be reduced through the use of spraying systems with
higher transfer efficiency.   Transfer efficiency, expressed as a percentage,
can be defined as the ratio of coating solids actually applied to the surface
of the component being coated to the amount of solids released from the spray
gun.22  Spraying  systems with  a  higher  transfer efficiency can coat the  same
surface area using less coating.  Therefore, the HAP emissions resulting from
the use of this equipment are reduced compared to applying the same coating
with conventional spray equipment.  The transfer efficiency values reported in
this section depend on coating sprayed, part configuration, spray booth air
velocity, and other variables.
      This section discusses the coating application equipment generally used
in the aerospace industry.  Most aerospace components are coated using manual
spray equipment.  The discussion includes the conventional application methods
as well as high efficiency application methods (e.g., electrostatic spray
guns, high volume, low pressure spray guns, and conventional high efficiency
methods).
      4.1.2.1.1  Conventional Airspray.  In conventional airspray systems,
compressed air is applied to the paint reservoir and the coating is forced
through a line and out the spray nozzle.  The coating is released at high
energy in a wide, flat spray pattern due to the high pressures involved.
Typically, the transfer efficiency for this system is 20 to 40 percent.23
      4.1.2.1.2  Airless Spraying.  Airless spray systems use hydrostatic
pressure (approximately 2,000 psi) to atomize the coating.  The transfer
efficiency for this system is typically 35 to 50 percent.24
      An air-assisted airless spray system, which is a variation of this
technique, uses lower pressures and lower air and fluid rates.  It is also
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more manageable to operate than airless spray alone.  The transfer efficiency
for this system is in the 30 to 60 percent range.25
      4.1.2.1.3  Conventional High Transfer Efficiency Application Methods.
Conventional high transfer efficiency application methods include dip, roll,
brush, and flow coating.  These methods are discussed below.
            4.1.2.1.3.1  Dip Coating.  With dip coating application, parts are
immersed into a tank of coating.  The parts are then removed from the tank and
held over it until the excess coating drips back into the tank.  This method
is simple and allows many different parts to be coated with high transfer
efficiency.26  However,  dip  coating  is limited  to parts  that can fit  into the
dip tank.  Other parts difficult to dip coat could include complex parts that
would trap the coating, allowing unequal coating thicknesses.
            4.1.2.1.3.2  Roll Coating,  In roll coating application, a series
of mechanical rollers are used to coat flat surfaces.  This method achieves
high efficiency with high rates of application and automation.  However, roll
coating is limited to flat parts.27
            4.1.2,1,3.3  Brush Coating.  In brush coating application, brushes
and hand rollers are used to apply the coating manually.  This  method is used
with operations (e.g., touch-up and detail painting) that cannot tolerate the
overspray associated with spray gun application.  For example,  if a  facility
needs to paint only the tail section  of an airplane, it may be  easier to brush
coat this area than to mask the entire plane to protect the rest of  the  shell
from overspray.  This application method typically involves high labor costs,
increased production time, and poor coating thickness control.28
            4,1.2,1.3.4  Flow Coating,  In flow coating application, the part
is conveyed over a closed sink, and a pumped stream of coating  gently flows
over the surface of the part.  The excess coating is drained into the sink,
                                      4-9

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filtered, and pumped to a holding tank for reuse.29  Flow coating is typically
limited to flat sheets and non-critical parts.   Coating thickness is difficult
to control using flow coating.
      4.1.2.1.4  High Volume Low Pressure Spray Guns.   High volume low
pressure (HVLP) and electrostatic spraying systems are the primary high
efficiency spray methods used by the industry.   HVLP spray guns use high
volumes [10 to 25 standard cubic feet per minute (scfm)] of low pressure [2 to
10 pounds per square inch gauge (psig)] air to  deliver the paint.  The lower
air pressure creates a lower particle speed, resulting in a more controlled
spray pattern with less overspray and bounce back from the substrate, thus
improving transfer efficiency.30
      HVLP systems have been in use in the United States for approximately 10
years.  In early systems, turbines were used to supply a high volume of low
pressure air to the spray guns through large hoses.  The second generation
used compressed air with an air regulator to maintain the required low
pressure.  The third and current generation of HVLP equipment uses restrictors
within the gun to reduce the atomization pressure to a maximum of 10 psi at
the air cap.31
      One disadvantage of HVLP spray guns is that some very high solids
coatings are difficult to atomize due to their  higher viscosities.  However,
when a turbine is used, the temperature of the  atomizing air increases which
aids in reducing the viscosity of the coating.32   A medium  commercial/rework
facility utilizes HVLP equipment with high solids paint and has had a
reduction of 22-30 percent in coating usage for various aircraft types.  Other
disadvantages of HVLP spray guns are that they  cannot be used with extension
nozzles, and they may slow production rates because of the low fluid delivery
rates.
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      It is estimated that HVLP can apply approximately 80 percent of the
coating currently used in the aerospace industry, including primers,
waterborne coatings, and both single and two-component topcoats.  The HVLP
technology has proven easy to use and maintain.  It also provides high
transfer efficiency and appears to be the preferred spray technology in the
aerospace industry at this time.33
      According to Section 114 questionnaire responses, application transfer
efficiencies up to 82 percent may be achieved using HVLP spray equipment.  A
large military/rework facility and a military/OEM facility reported that HVLP
increases transfer efficiency from 40 to 60 percent.  A medium commercial/ and
military/OEM facility stated that they are achieving a minimum transfer
efficiency of 65 percent compared to 25 to 35 percent efficiency of
conventional spray equipment, and a medium military/OEM facility estimated an
increase in transfer efficiency from 25 to 65 percent.  Finally, a medium
commercial/OEM facility claimed that replacing all conventional spray
equipment with HVLP equipment increased transfer efficiency from 25 to 82
percent.
      Table 4-1 shows the reduction in emissions obtained from the Section 114
questionnaire responses from various facilities utilizing high transfer
efficiency equipment such as HVLP or electrostatic equipment, either alone, in
conjunction with each other, or,  in one case, HVLP equipment with high solids
coatings.
      4.1.2.1.5  Electrostatic Spray Guns.  With electrostatic spray systems,
atomized particles of coating acquire an electric charge as they pass through
a high voltage field at the end of the spray nozzle.  This electric charge
causes the particles to be attracted to the parts being painted, which are
electrically grounded.  Although  other substrates can be pre-treated with
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                               TABLE  4-1
Percent Reduction in Emissions with High Transfer Efficiency Equipment
                         from  Section  114 Data
Size
Large
Large
Large
Large
Large
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Ned i urn
Medium
Med i urn
Small
Small
Commercial
or
Military
Military
Military
Military
Commercial
Commercial
Commercial
Military
Military
Commercial
Military
Military
Military
Military
Military
Military
Military
Military
Mi 1 i tary
Commercial
Commercial
Commercial
Commercial
Commercial
Commercial
Military
OEM
or
Rework
OEM
OEM
OEM
OEM
OEM
OEM
OEM
Rework
OEM
OEM
Rework
OEM
OEM
OEM
OEM
OEM
Rework
Rework
OEM
OEM
Rework
Rework
OEM
OEM
OEM
High Transfer
Equipment
HVLP
HVLP
HVLP
Unspecified
Unspecified
HVLP
HVLP
HVLP and
Electrostatic
HVLP and
Electrostatic
HVLP
HVLP
Electrostatic
HVLP and
Electrostatic
Unspecified
Unspecified
HVLP and
Electrostatic
HVLP and High
Solids
Unspecified
HVLP
% Reduction in
Emissions
20%
20%
25%
30%
18%
25%
20-40%
40%
40%
40%
10%
30-40%
35-40%
30%
33%
50%
22% for large aircraft
25% for medium aircraft
30% for small aircraft
30%
28%
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conductive coatings, this technology is primarily used for metal parts.  The
electrostatic effect can be utilized in conjunction with air spray, airless,
and air-assisted airless systems to enhance the transfer efficiencies of these
basic technologies.  See Table 4-1 for examples of percent reduction obtained
at various facilities using electrostatic spray guns or electrostatic spray
guns in combination with HVLP spray guns.  Application transfer efficiencies
up to 90 or 95 percent may be achieved using electrostatically enhanced
spraying.34
      4.1.2.2  Enclosed sorav gun cleaners.  Spray guns are typically cleaned
at the end of every job, as well as between color changes.  Manual cleaning of
spray guns involves disassembling the gun and placing the parts in a tray
containing an appropriate cleaning solvent.  The residual paint is brushed or
wiped off the parts, then the cleaning solvent is sprayed through the gun
after it is reassembled.  Enclosed spray gun cleaners, however, are completely
enclosed units that spray the cleaning solvent through and over the spray gun.
The enclosed unit eliminates most of the exposure of the cleaning solvent to
the air, thereby greatly reducing the HAP emissions from evaporation.35
Additionally, Factory Mutual has approved at least one enclosed gun cleaner.36
      4.1.2.3  Proportional Paint Mixers.  The majority of coatings used in
the aerospace industry are multi-component mixtures, consisting of a base
component and one or more catalyst components.  The components must be
thoroughly mixed in the proper ratio immediately before application.  When
this mixing is performed manually, a greater volume of coating is mixed than
will actually be used to ensure that there is enough coating available to
complete the job.   In contrast, proportional paint mixing equipment has been
developed to mix two coating components  prior to application.  The two
components then cure on the part through a chemical reaction.  The paint used
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is a raulti-component system in which a base pigment is mixed with a catalyst
and then applied to the aircraft.  Proportional  paint mixers mix the base
pigment and the catalyst within the spray gun or in a separate mixing chamber
as the paint is applied.  These systems generally consist of two positive
displacement pumps, an air regulator, and a pressure relief safety valve.  The
pumps automatically dispense the components in a pre-determined ratio.  Since
the paint is mixed and supplied on demand, these systems greatly reduce the
amount of coating wasted due to batch mixing.  In batch mixing, a significant
amount of paint is often left unused at the end of the job because the amount
of the batch was determined by an estimate of the amount needed for the job.
The unused- paint became waste.37   The use  of  proportional  paint  mixers  result
in reduced coating waste and, consequently, reduced emissions.
      4.1.2.4  Non-chemical Deoaintinq Processes.  Methylene chloride is the
primary solvent used in chemical strippers in the aerospace industry.
However, several methods have been developed or are under development to
replace methylene chloride.  The alternatives presented in the Section 114
responses are discussed below.
      4.1.2.4.1  Plastic Media Blasting (PMB).  This process is an abrasive
blasting process that uses plastic beads as the blasting media.  Several
different types of plastic beads, as defined by their chemical composition,
exist.  This process uses modified sandblasting equipment.  The modifications
are necessary to recycle the media and properly separate out contaminants.
Plastic media blasting may require a dedicated facility to maintain low levels
of media contamination.  In addition, it produces large amounts of hazardous
waste (i.e., spent media and paint chips).38
      Plastic media blasting has been determined to be an acceptable process
for paint removal from high strength steel and titanium parts.  It can
                                     4-14

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successfully produce strip rates of 5.6 mz/hr (60 ft2/hr)  and  above.39
Additionally, at at least one facility, labor costs for plastic media blasting
operations are about 40 percent less than those for chemical stripping
operations.40  However,  in  the  case  of  aluminum  and  composite  substrates,
strict controls are necessary to obtain acceptable results.  These controls
include media contamination levels,  process parameters, operator training, and
quality assurance.  There exists some disagreement on its effect on fatigue,
crack growth, and crack detection.  One study showed increases in the crack
growth rates and reductions in the fatigue life of aluminum structures.41   A
follow-up study showed that the media contamination levels and aggressive
blasting parameters were the main causes of these problems.42
      4.1.2.4.2  Sodium Bicarbonate Blasting.  This process uses sodium
bicarbonate and water as the abrasive blasting media.  The media is not
recyclable and the sodium bicarbonate is partially soluble in water (up to 10
percent).  The water and sodium bicarbonate are mixed at the nozzle of
modified sandblasting equipment.  As with plastic media blasting, the
modifications are necessary to recycle the media and properly separate out
contaminants.  The water is used for dust control and to absorb some of the
impact energy in order to minimize damage to the substrate.43
      This process has the potential to be used on detailed composite parts.
It can selectively remove the enamel layer without removing the primer layer.
Therefore, the possibility of damaging the substrate is minimized.  However,
tests have not been performed to determine if the process damages the
substrate (i.e., crack growth rates, fatigue, fiber damage, and crack
detection).44
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      The surface obtained after stripping is much smoother than surfaces
stripped with plastic media.   However,  damage to the clad layer of the outer
skin of the aircraft may still occur.   The strip rates,  approximately
2.8 mz/hr (30 ft2/nr),45 are almost half that of plastic  media blasting.  As
with plastic media blasting,  labor costs for at least one facility are about
40 percent less than those for chemical stripping operations.46
      4.1.2.4.3  Carbon Dioxide Blasting Process.  This  process uses solid
carbon dioxide pellets to abrasively and cryogenically remove paint from the
substrate.  The equipment uses liquid carbon dioxide generated from other
industrial processes and converts it into the solid form.  The solid pellets
are then propelled with air at a pressure of 250 psi or  greater to remove the
paint.  The pellets disintegrate upon impact and sublimate.  The paint chips
are the only waste generated.47
      Studies have shown that this process has a large potential for damage,
especially on thin gauge material.  Warpage, dimpling, and blistering of the
clad layer have been documented at pressures lower than  the recommended 250
psi.  The slow removal rates at which these systems currently operate
increases the possibility of damage to the aircraft.48 Also,  the  associated
high noise level is a concern.
      4.1.2.4.4  Ice Crystal Blasting.  This process uses ice crystals as the
blasting media.  The mechanism for the process is a combination of fracturing,
abrasion, and cryogenic effects.  The process uses machinery that is self-
contained in a trailer (includes the icemaker and compressors).  The ice is
propelled at the nozzle to minimize the loss of particle size.49
      The results from lab tests show selective stripping of the enamel was
possible on aluminum substrates.  However, scale-up of the process has
                                     4-16

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presented some difficulties in obtaining the same results as obtained with the
lab set-up.50
      The waste generated by this process consists of water and paint chips.
The process has demonstrated slow removal rates and the effect on the
substrate is currently unknown.51
      4.1.2.4.5  Wheat Starch Blasting.  This abrasive blasting process uses a
recyclable polymerized wheat starch pellet as the blasting media.  The
equipment used for this process is modified plastic media or sand blast
equipment with the media recycle and separation devices optimized for the
wheat starch.52  Preliminary results  show this  method  to  be  very  promising  for
both aluminum and composite structure.
      The waste generated consists of a biodegradable wheat starch dust and
paint chips.  The hazardous constituents can be separated out after degrading
the starch to a liquid form.  However, the process may require a dedicated
facility or a blast and vacuum unit  (blasting equipment that simultaneously
vacuums the created dust particles).  In addition, the preliminary results
show that the stripping rate of the process, approximately 2.8 m2/hr
(30 ft2/hr), is approximately half of the rates obtained by plastic media.53
      4.1.2.4.6  Water Jet  Stripping.  This process is a two step operation.
The first step uses a paint softener to loosen the bond between the enamel and
primer layer.  The second step uses high pressure water to remove the loosened
enamel layer, leaving the primer layer intact.54
      Strip rates achieved  by this process are relatively high and depend upon
the softener used.  The strip rates, 5.6 m2/hr (60 ft2/hr),  are  comparable  to
plastic media and the effect on the  substrate  is minimal.  However, chemical
waste is still generated.   In addition, adequate prevention of water
entrapment and the effects  on composite structure need to be addressed.55
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      4.1.2.4.7  High Pressure Water Jet.   This process uses water at ultra
high pressure for paint removal.   The process uses a unique nozzle
configuration and must be robotically controlled.   The strip rates obtained
are comparable to those obtained  with plastic media.  It can also selectively
remove the topcoat layer.  No chemical  waste is generated;  however, the
wastewater stream may contain hazardous constituents.56
      Qualification tests are being performed for the high  pressure water jet
at some facilities.  It has not been demonstrated on composite surfaces, and
the effects on the substrate are  unknown.   Manual  operation may not be
possible and the possibility of water getting in the joints and around
fastener heads and door frames is of major concern.57
      4.1.2.4.8  Excimer Lasers.   This process uses a pulsed laser to remove
the coatings by ablative means with minimal heating of the  substrate.  The
laser uses halogen gases (i.e., krypton fluoride [KrF] and  xenon chloride
[XeCl]) as the ultraviolet light  source.  The process is extremely precise and
requires robotic controls.58
      Based on laboratory studies, the strip rates are slower than some of the
other paint removal processes.  In addition, the laser is difficult to use on
complex, contoured parts.  Although some scale-up problems  have been
encountered, the process does show some promise for aluminum substrates.  The
full effects on all substrates has yet to be determined.  Additionally, the
process generates very little waste.  Experiments are being performed to
determine if HAPs are being released during the ablative process.59
      4.1.2.4.9  Xenon Flash Lamp.  This process consists of a pulsing lamp
using a xenon light source.  The  high intensity light pulses supply the energy
required to ablate the coating.  Pigment and carbon residues are left on the
surface after paint removal.60
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      Only preliminary studies have been conducted to date.   The strip rates
obtained by this process are relatively slow compared to other methods.
However, the amount of paint removal is controllable.  The residues that
remain on the surface and the toxic by-products generated need to be studied
in greater detail.  The effects on aluminum and composite substrates also need
to be determined.  The use of this process on complex, contoured parts is
difficult, as with the laser system.  Also, the process is noisy and
maintenance is high.61
      4.1.2.4.10  Carbon Dioxide Pulsed Laser.  This pulsed laser uses a
carbon dioxide light source.  The light pulses supply the energy necessary to
ablate the coatings.  This process also contains a vacuum filtration system to
collect the toxic by-products generated during ablation.62
      Studies show that it is a promising technique, and that the extent of
paint removal is controllable.  However, the strip rates achieved are very
                                                   »
slow.  No adverse structural effects to the aircraft have been detected.
While subsequent paint adhesion tests are promising, toxic byproducts and
effects on the substrate need to be studied in more detail.   In addition, the
use of this process on complex, contoured parts is difficult.63
4.1.3  Work Practice Standards
      Work practice standards are changes in the method of operation that do
not affect the products used in the process or the process itself, but result
in a reduction in emissions.  The aerospace industry has implemented work
practice  standards programs for housekeeping measures and managed chemical
distribution systems.
      Emissions of HAP compounds, particularly solvents, can be reduced by
limiting  both the amount of the material exposed to the atmosphere and the
length of the exposure.  The emission reductions can be achieved by
                                     4-19

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implementing housekeeping measures whereby solvent soaked rags used for hand-
wipe cleaning are placed into bags or containers that are kept closed.  This
eliminates the continual evaporation of the solvent from the rags when they
are not in use.  The bags or containers can then be collected and disposed in
such a manner (e.g., by incineration) to eliminate any further solvent
emissions.64
      Managed chemical distribution systems centralize the distribution of
solvents and coatings and controls the amount of these materials allowed to be
used for a particular task.  A control plan typically consists of centralized
distribution to authorized employees who have taken a safety course and
understand the pollution potential of the materials.  In many cases, workers
check out material for immediate use and then return any leftover chemical for
storage or hazardous waste pickup.  The control plan also limits the amount of
solvent issued to each worker during a shift.  This results in the reduction
                                        *
of total solvent consumption, but also requires each worker to carefully
monitor solvent use so that the required cleaning is accomplished without
impairing product quality.  Additionally, the centralized distribution helps
keep accurate usage records, assure full use of limited pot-life materials,
manage inventory, and reduce waste.  In this way, waste solvent and coatings
are reduced, and emissions from these waste materials are eliminated.65
4.2  CONTROL DEVICES
      The removal efficiency of each control device on the basis of the total
volatile organic compound  (VOC) concentration is included in each section.
Since detailed data regarding HAPs are generally not available, HAP removal
efficiency is assumed to equal VOC removal efficiency.  Removal efficiency
values are based on well maintained units with no emissions from leaks.56
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4.2.1  Carbon Adsorbers
      In carbon adsorption systems, activated carbon is used as the adsorbent
for removing gaseous organic contaminants from an exhaust stream.  The air
stream containing HAPs is exhausted into the activated carbon bed and the
contaminants are retained on the carbon due to chemical and physical forces.67
Figure 4-1 is a schematic of a typical two-bed regenerative carbon adsorption
system.68
      Adsorption systems are used to remove VOCs from gas streams when strict
limits on the outlet concentration must be met, or when recovery of the VOC is
desired.  Adsorption is effective on inlet concentrations ranging from a few
part per billion to several thousand parts per million, and a flow rate of
several hundred to several hundred thousand cubic feet per minute.  Carbon
adsorbers typically have a removal efficiency of 95 to 99 percent.69
      Many factors affect the efficiency of the adsorption process.  Four
major ones are:  (1) temperature,  (2) humidity, (3) contaminants, and (4)
velocity.  The adsorptive power of the activated carbon decreases with
increases in temperature.  Secondly, at humidities greater than 50 or 60
percent, the solvent adsorption efficiency decreases, as water and solvent
molecules compete for adsorption sites.  In addition, contaminants such as
high boiling point compounds may reduce the adsorption efficiency, and
particulate matter will foul the surface of the activated carbon.  Finally,
the velocity of the air stream in  the adsorber vessel determines the time the
air stream remains in contact with the carbon beds (i.e., the residence time).
The longer the residence time, the better chance the solvent molecule has in
finding  an available site on the activated carbon.70
      Over time, the efficiency of the system is reduced due to the
contaminants in the carbon.  If a  unit is allowed to become saturated,
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contaminants are able to vent out of the unit and the efficiency of the
control device is zero.  Additionally, if certain solvents are allowed to
saturate the carbon substrate, there is a potential  for carbon bed fires.  At
the first indication of breakthrough (an increase of organics in the exhaust
stream), the bed must either be replaced or regenerated.71
      In a typical large carbon bed system, the contaminated air stream passes
through multiple adsorbers in parallel while another adsorber is in
regeneration or standby mode.  The clean air is discharged through a common
stack.  After a length of time, the adsorber that has been on-line the longest
is taken off-line for regeneration and the standby adsorber is brought on
line.  The length of the adsorption cycle depends on the type and amount of
contaminants and carbon present, but an 18 to 30 hour cycle is typical.
      Several options for handling the spent carbon from carbon adsorption
systems exist.  One option is to send the spent carbon off-site for disposal.
A second option is to strip the contaminants from the carbon with steam or hot
gases.  This procedure does not require removing the carbon from the adsorber
and produces less waste than the non-regenerative options.  This option does,
however, produce a contaminated condensate that must be treated before
discharge.  A third option is to send the carbon off-site for reactivation.
This process heats the carbon in the absence of air to the combustion
temperature of the solvents adsorbed by the carbon.   The carbon can then be
reused.72
      Steam is generally used to regenerate the carbon bed for vapor phase
recovery processes because it is relatively cheap, usually already available
at industrial sites, and easily condensed.  Distillation or decanting
techniques are used to remove the recovered solvent from the condensate.
After the bed has been regenerated with steam, the bed should be cooled and
                                     4-23

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dried.  This step is done to reduce the moisture level in the bed so that
solvent losses to the atmosphere may be minimized during the initial startup
of the regenerated bed.73
4.2.2  Incinerators
      Two basic types of incinerators, thermal and catalytic, are used in the
aerospace industry to remove VOC contaminants.  Each type is discussed below.
      4.2.2.1  Thermal Incinerators.  Thermal incinerators are generally used
on air streams with dilute concentrations of VOCs.  These control devices have
minimal dependence on the characteristics of the VOC contaminants, so they can
be used to control a wide variety of emission streams.74   Thermal  incinerators
can achieve removal efficiencies of 98 percent and higher.75
      A schematic diagram of a thermal incinerator is shown in Figure 4-2.76
The basic operation of thermal incinerators involves raising the inlet air
stream to the incineration temperature of the contaminants and maintaining
that temperature for a specific residence time.  The waste heat content of the
incinerator exhaust stream is used to preheat the inlet air stream.  An
auxiliary fuel is then typically required to raise the air stream temperature
to the incineration temperature.  The preheated process exhaust stream enters
the incineration combustion chamber that is maintained at a minimum of 760°C
(1400°F) by fuel-fired burners and the thermal energy released by the VOCs.
This incineration process converts the incoming VOCs primarily to carbon
dioxide artd water vapor.  The airstream then leaves the combustion chamber and
95 percent of the thermal energy of the clean exhaust stream is recovered to
be reused as preheat for the next inlet cycle.  The clean airstream is then
discharged by being drawn through an exhaust manifold by an exhaust fan and
valve mechanism.77
                                     4-24

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      Three important design considerations of the combustion chamber are
residence time, temperature, and turbulence.  The residence time, which must
be sufficient to permit complete combustion of the VOC,  is about 0.2 to 0.8
seconds.  The necessary temperature range for thermal  incineration is 760°C to
871°C (1400°F to 1600°F), and turbulence facilitates the mechanical mixing of
oxygen, heat, and VOCs necessary for maximum removal efficiency.  The specific
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design values depend on the design and manufacture of the incinerator.
      4.2.2.2  Catalytic Incinerators.  Catalytic incinerators are similar to
thermal incinerators except that they use a catalyst (a substance that
accelerates the rate of oxidation without undergoing a chemical change itself)
to assist in the oxidation of VOCs to carbon dioxide and water.  Figure 4-3
shows a typical catalytic incinerator.79  The  solvent-laden air enters  the
device and is preheated to 260°C to 460°C (500°F to 860°F) by  both a primary
heat exchange and a preheater.  The airstream is then blown across a catalyst
site where oxidation occurs.  The catalyst catalyzes the reaction with oxygen,
causing it to take place at a lower temperature, thereby saving fuel.  Typical
catalyst materials used are noble metals, such as platinum or palladium
dispersed on an alumina support.  About 98 percent of the incoming VOC can be
destroyed in this manner.80
      A potential limitation of this system in some services is contamination
of the catalyst surface.  Materials in the emission stream such as bismuth,
lead, arsenic, mercury, phosphorus, zinc, and sulfur can poison and decrease
or destroy the catalyst's efficiency.  Additionally, liquids or solids can
deposit on catalysts, forming a coating which reduces the catalyst's
performance.  The life of the catalyst is also limited by erosion, attrition,
vaporization, and thermal aging.  However, with proper controls, catalysts can
last two to five years.81
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4.2.3  Ultraviolet Oxidation
      An ultraviolet light oxidation (UVOX) system has been developed as an
abatement device for low VOC concentration air streams.  Figure 4-4 gives a
                                              fi?
schematic of the ultraviolet oxidation system.   The  air stream passes
through particulate filters, then enters a reactor where it is exposed to
ultraviolet light which initiates the oxidation of the VOCs.  Ozone and other
oxygen-based oxidants are injected into the reactor to react with the VOCs in
the air stream to begin the oxidation of VOCs into carbon dioxide and water.
The ozonated air enters the bottom of a packed column scrubber, and ozonated
water enters the top.  The air and water move countercurrently in the column,
passing over mass transfer media, or packing media.  This scrubbing process
furthers the reaction of the oxidants with the VOCs.  The airstream then
travels through activated carbon beds.  Although the airstream is considered
clean after the packed column treatment, the carbon beds are final protection
against any release of unreacted pollutants.  Two carbon beds are used with
the system.  One bed can be placed off-line and cleaned with ozone while the
other bed is in use.  The water in the packed column is recycled, reozonated,
and filtered so that there is little loss except for evaporation.  The only
regularly required disposal is for the particulate filters and occasional
replacement of the carbon beds.  A typical removal efficiency for UVOX is
reported to be 95 percent.83'84
4.2.4  Activated Carbon Fiber Adsorbent
      Another technology has been developed to control low concentration VOC
emissions (e.g., paint spray booths).  This technology utilizes an activated
carbon fiber adsorbent to initially capture the VOC emissions.  The adsorbent
system consists of a honeycomb structure element made of activated carbon
fiber paper in corrugated form.  This structure adsorbs the VOCs  in the
                                      4-28

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exhaust stream.   As the activated carbon structure becomes saturated, the VOCs
are desorbed using hot air.  The portion of the activated carbon structure
that was regenerated then begins the adsorption cycle again.85
4.2.5  Catalvst-coated Filter Media
      Low concentration organic emissions (e.g., paint spray booths) can be
controlled through the use of a catalyst-coated'filter media.  The catalyst
material is impregnated onto the fibers of a dry filter which can then be used
wherever conventional dry filters are used.  The catalyst material, unlike
activated carbon, permanently binds the organic material into its crystalline
matrix so that it will not later desorb.  In addition to the coated filters,
the catalyst material can be used in a granular form to control emissions.86
4.2.6  Baqhouses
      Baghouses, one type of fabric filter system, operate by capturing
particles on the surface of closely spaced fibers of the filter media.  Woven
and felt are the two general types of fabric used for bag filters.  In the
case of woven filters, the pores of the cloth are many times larger than the
particles; however, within a few minutes of operation, a filter cake (layer of
dust) will form on the filter that effectively reduces the pore size and
increases collection efficiency.  The pores in felt filters are small enough
so that a coated layer not need form before a good collection efficiency can
be achieved.  Control efficiencies of 99 percent or greater can typically be
achieved.87  Typical  cloth  filters  are  shown  in  Figure 4-5.88'89
4.2.7  Mechanical Centrifugal Separator (Rotoclone)
      Mechanical centrifugal separators, or rotoclones, operate by capturing
particles with the use of centrifugal force.  With this system, the fan and
dust collector are combined in a single unit.  The exhaust stream is directed
into a centrifugal fan.  The fan blades are shaped to direct particles by
                                     4-30

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      , - Beater correcting rod
         j? Screen beater
Bag
support
and  *
shaking
mechanism
Dust discharge
               Icl
                                                                     Air inlet
                                                     '-Dust hopper
                                                        (b)
                                                               OuHltflpf
                 Figure 4-5.  Typical cloth filters:

            (a) Screen  or envelope type (section view)
           (b) Screen or envelope type (cutaway view)
             (c) Bag type (cutaway view)
             (d)  Bag type  (sectional view)

                     [Reference 89, p. 20-92]
                                   4-31

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using centrifugal  force onto the unit's walls and then into a slot leading to
a collection bin.   The gas stream continues to an outlet.90   Control
efficiencies of 98 percent or greater have been reported.91   A typical
rotoclone dust collector is shown in Figure 4-6.92
4.2.8  Dry Filters for Spray Booths
      During the coating application process, paint is sprayed from the spray
gun onto the product being painted.  Depending on the method of spraying,
various amounts of coating overspray (e.g., paint participates and solvent)
are lost to the surrounding air, floor, and walls.   When painting is done
within a spray booth, exhaust air carries the overspray away from the worker
and the product.  This is done for several reasons.  Removal of overspray
prevents accumulation and concentration of hazardous components of the
coating, preventing a buildup that could violate health, safety, or fire
protection regulations.  Additionally, air moving through the booth carries
overspray away from the product, avoiding the detrimental consequences of
particulates settling on freshly painted surfaces.   Finally, the air flow can
be directed to a capture device.  Capturing and removing the particulates from
the exhaust air stream eliminates the release of these particulates to the
outside air.93
      One way to remove overspray particulates from the exhaust air flow is to
use a dry filter media.  Air flow in a booth equipped with dry filter media
generally passes from the painter, over the part, and through a filter bank.
This air flow can be horizontal or vertical as in a downdraft spray booth.
Examples of typical dry filter media includes:  (1) paper filters formed into
double accordion folds with staggered holes for air flow, (2) non-woven mesh
type pads in series, and (3) non-woven cloth curtains that are roll fed across
the face on the booth.94   Dry  filter media must  replaced when the  pressure
                                     4-32

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                                                     4/>- outlet
    Air inlet
(a)
    Bypass air
             Figure 4-6.  Typical mechanical centrifugal separator.
                         Rotoclone (cutaway view).
                          [Reference 89, p. 20-87]
                                    4-33

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drop across the filters exceeds the rated pressure drop for the filter, which
is caused by accumulated overspray.  The excessive pressure drop can either
lower the air flow rate below acceptable levels,  or cause one or more filters
to tear or pull away from its mounting frame.
4.2.9  Waterwash Spray Booths
      A second way to control overspray particulates is to use a waterwash
spray booth.  Similar to the dry filter spray booths, air flow can move
horizontally or vertically into the face of the waterwash booth.  The water
removes the particulates by two methods.  First,  air is drawn through a
continuous curtain of moving water and particulates are removed by contact
with the water.  Second, the air flow makes a sudden change in direction or
velocity.  As a result of inertial force, the particulates are impinged on the
booth walls and are washed down by the water flow.  Waterwash spray booths
typically require very little maintenance.  Periodically, the water is removed
from the booth, leaving paint sludge in the water sump that must then be
removed.  Additionally, many companies recycle the water through the spray
booth filter system indefinitely with water added only to account for
evaporation.  During the cycle, the water is typically treated to remove the
residue paint particulates and the resulting paint sludge is disposed of as
hazardous waste.95
                                     4-34

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4.7   REFERENCES
      1.     Surface Coating of Plastic Parts Control Techniques Guideline,
            Draft, U.S. EPA, Chemicals and Petroleums Branch,  Research
            Triangle Park, NC, October 1991., p. 4-2.

      2.     Compliance Assistance Program-Surface Coating Operations:
            Aerospace. Air Resources Board Compliance Division, July 1990., p.
            200-5.

      3.     Reference 2, p. 200-5.

      4.     Reference 1, p. 4-2.

      5.     Reference 1, p. 4-3.

      6.     Byrd, R. W., "The Development of Low Emission High Performance
            Aerospace Coatings," National Association of Corrosion Engineers,
            August, 1982. p. 41.

      7.     Reference 1, p. 3-18.

      8.     Reference 1, p. 4-5.

      9.     Reference 1, p. 4-7.

      10.   Reference 2, p. 200-6.

      11.   Reference 1, p. 4-7.

      12.   Reference 1, p. 4-7.

      13.   Response from Naval Aviation Depot, Alameda, California, on the
            February 28, 1992, trip report.  April 17, 1992, P. Pentony.

      14.   Irving, R.R., "Rohr First Licensee of New Process to Shield
            Aluminum from Corrosion," Metals and Materials.

      15.   Reference 14.

      16.   Quitmeyer, JoAnn, "Aqueous Cleaners Challenge Chlorinated
            Solvents," Pollution Engineering, December 1991.  p. 91.

      17.   Reference 2, p. 200-5.

      18.   Hamilton, J. and K. Feser, Minutes from EPA/Aerospace Conference,
            June 31, 1992. p. 9,

      19.   T. Phillips and S. Evanoff, General Dynamics, Fort Worth, to V.
            Boothe, EPA:CPB.  January 20, 1993.  Alternative cleanup solvent
            strategy for aerospace CTG/recently implemented General Dynamics
            Fort Worth Division Program.

      20.   Reference 18, p. 13.

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21.   Section 114 Questionnaire Response by United Airlines, Attachment
      D-6., p. 14.
22.   Glossary for Air Pollution Control of Industrial Coating
      Operations. Second Edition. EPA-450/3-83-013R, December 1983. p.
      21.
23.   Evaluation of RACT for VOC Emissions from Drum Coating Operations
      at Plants Manufacturing. Reconditioning, and Rebuilding Steel
      Drums and Pails, Solutions for Energy, Environment, and
      Technology, May 1986. p. 5-16.
24.   Reference 23.
25.   EPA: AP-42.  Compilation of Air Pollutant Emission Factors.
      Section 4.2.2, Industrial Surface Coating.  April 1981. pp.
      4.2.2.1-1 - 4.2.2.14-18.
26.   Control of Volatile Organic Emissions from Existing Stationary
      Sources. Volume VI: Surface Coating of Miscellaneous Metal Parts
      and Products. EPA-450/2-78-015, June 1978, p. 1-7.
27.   Reference 2, p. 200-24.
28.   Reference 2, p. 200-24.
29.   Reference 26, p. 1-6.
30.   Reference 1, p. 3-15.
31.   Reference 18, p. 7.
32.   Reference 2, p. 200-22.
33.   Reference 2, p. 200-22.
34.   Reference 2, pp. 200-22 - 200-23.
35.   Trip Report - Naval Aviation Depot, Alameda, California on
      February 28, 1992.
36.   R. Robb, Herkules Equipment Corp., to K. Feser, PES.  May 24,
      1993.  Transmittal of equipment approval for paint gun washer from
      Factory Mutual Research, dated May 18, 1993.
37.   Reference 35.
38.   Reference 21, pp. 3 - 4.
39.   Reference 21, pp. 3 - 4.
40.   Reference 13.
41.   Reference 21, pp. 3 - 4.
                               4-36

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42.   Reference 21, pp. 3 - 4.
43.   Reference 21, pp. 5 - 6.
44.   Reference 21, pp. 5 - 6.
45.   Reference 21, pp. 5 - 6.
46.   Reference 13.
47.   Reference 21, pp. 6 - 7.
48.   Reference 21, pp. 6 - 7.
49.   Reference 21, pp. 7 - 8.
50.   Reference 21, pp. 7 - 8.
51.   Reference 21, pp. 7 - 8.
52.   Reference 21, p.  10.
53.   Reference 21, p.  10.
54.   Reference 21, p.  8.
55.   Reference 21, p.  8.
56.   Reference 21, p.  9.
57.   Reference 21, p.  9.
58.   Reference 21, p.  11.
59.   Reference 21, p.  11.
60.   Reference 21, p.  12.
61.   Reference 21, p.  12.
62.   Reference 21, p.  13.
63.   Reference 21, p.  13.
64.   Reference 19.
65.   Trip  Report:  Northrop  B-2  Final Assembly  Facility,  Palmdale,
      California,  on  March 3,  1992,  and  Northrop Aircraft  Division,  El
      Segundo, California, on  March  4, 1992.
66.   Handbook: Control Technologies for Hazardous Air  Pollutants,
      EPA/625/6-91/014, June  1991. p. 3-3.
67.   Reference 2,  p.  200-26.
                                4-37

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68.   Reference 66, p. 4-31.
69.   Reference 66, p. 3-4.
70.   Symposium on Aerospace Coating Technology and Regulations,
      Oakland, CA, November 14-15, 1988.  Vara, Thomas E., "Theory of
      Carbon Adsorption and Distillation Technology as Applied to VOC
      Control in the Coatings Industry,", pp. 3-4.
71.   Reference 2, p. 200-27.
72.   Section 114 Questionnaire Response from Rohr, Inc. Facilities  in
      Riverside County, CA.
73.   Reference 70, pp. 7 - 8.
74.   Reference 66, p. 3-3.
75.   Reference 1, p. 4-18.
76.   Reference 1, p. 4-17.
77.   Reference 1, pp. 4-15 - 4-18.
78.   Reference 1, p. 4-18.
79.   Reference 1, p. 4-19.
80.   Reference 1, p. 4-18.
81.   Reference 66, p. 3-3.
82.   Terr-Aqua Enviro Systems Company Brochure
83.   Reference 82.
84.   Letter.  Jackson, T., Terr-Aqua Enviro Systems, Inc.,  to Susan
      Wyatt, EPArCPB.  May  15, 1992.  Comments on UVOX system.
85.   KPR Solvent Concentrating Systems-Bulletin 11300.  MetPro Company,
      System Division Company Information.  No date.  4 pp.
86.   Trip  Report  - Seymour Johnson Air  Force Base, North Carolina on
      July  29, 1993.
87.   Reference 66, p. 3-13.
88.   Reference 66, pp. 4-64  - 4-70.
89.   Perry, Robert H. and  Cecil  H. Chilton, Chemical Engineers'
      Handbook. 5th Edition, McGraw-Hill Book Company, 1973., pp. 20-89
      -  20-94.
90.   Reference 89, pp. 20-87.
                               4-38

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91.   Section 114 Questionnaire Response from Boeing-Kent.
92.   Reference 89, pp. 20-87.
93.   Industrial Spray Booths.  Catalog SB-12, Selecting a Spray Booth,
      Binks Manufacturing Company.  March 1993.  p. 6-1.
94.   Reference 93. pp. 6-4, 6-8, 6-16.
95.   Reference 93.  p. 6-21.
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                  5.0  MODIFICATION AND RECONSTRUCTION

      National emission standards for hazardous air pollutants (NESHAP)
apply to both new and existing facilities that are major sources [as
defined in Section 112(a)(l) of the Clean Air Act Amendments of 1990
(CAAA)] of hazardous air pollutant (HAP) emissions.  The maximum degree
of reduction in emissions for new sources (those sources for which
construction commenced after the date of proposal of this standard)
shall not be less than the maximum achievable control technology (MACT)
demonstrated by the best controlled similar source.  MACT standards for
existing sources may be equally or less stringent than the MACT
standards for new sources, but cannot be less stringent than the level
of control achieved by the best performing 12 percent of existing
sources.
      After the effective date of a permit program under Title V of the
CAAA, a major source which undergoes a modification that is not offset
by reductions in emissions of a more hazardous pollutant at that source
must meet the MACT emission limitation for existing sources.  A major
source which is constructed or undergoes a reconstruction, however, must
meet the MACT emission limitation for new sources.  Modification and
reconstruction are further defined in Section 5.1, and their
applicability to the aerospace manufacturing and rework industry is
discussed in Section 5.2.
                                  5-1

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5.1  PROVISIONS FOR MODIFICATION AND RECONSTRUCTION
5.1.1  Modification
      Section 112(a)(5) of the CAAA defines modification as "any
physical change in, or change in the method of operation of,  a major
source which increases the actual emissions of any hazardous  air
pollutant emitted by such source by more than a de minimi's amount or
which results in the emissions of any hazardous air pollutant not
previously emitted by more than a de minimis amount."  Changes such as
routine maintenance, repair, and replacement of worn parts or an
increase in the hours of operation are not considered modifications.
      Certain changes, even though they result in an increase in HAP
emissions greater than a de minimis amount, are not considered
modifications.  Section 112(g)(l) of the CAAA establishes an  offset
provision such that a physical change in, or change in the method of
operation of, a major source will not be considered a modification if
the change also results in an equal or greater decrease in the quantity
of emissions of another hazardous air pollutant (or pollutants) deemed
by the EPA to be more hazardous.  The owner or operator of the source
shall submit a showing to the EPA (or the State) documenting  the
increase in emissions and the corresponding decrease of the more
hazardous pollutant.
      Modifications that are not subject to the offset provision must
meet the MACT emission limitation for existing sources.  After the
effective date of a permit program under Title V of the CAAA, no
modification may be made to a major source until such modification is
approved by the EPA (or the State).
                                   5-2

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      The key to determining if a change is considered a modification is
whether actual emissions from the emission point or points, process,
product line, or entire facility modified have increased on a mass per
time basis (kg/hr) as a result of the modification.  Changes in the
emission rate may be determined by emission factors as specified in the
latest issue of "Compilation of Air Pollution Emission Factors," EPA
publication No. AP-42, or other emission factors determined by EPA to be
superior to AP-42 emission factors.  In cases where utilization of
emission factors does not clearly demonstrate that emissions increase or
decrease, material balances, continuous monitoring data, or manual
emission tests may be used to determine changes in emission rates.
5.1.2  Reconstruction
      Reconstruction is defined in 40 CFR 60.15 as "the replacement of
components of an existing facility to such an extent that:
      (1)   The fixed capital cost of the new components exceeds 50
            percent of the fixed capital cost that would be required to
            construct a comparable new facility, and
      (2)   It is technologically and economically feasible to meet the
            applicable standards."
For this definition, "fixed capital costs" means the capital needed to
provide all the depreciable components.
      If the owner or operator of a major source is planning to replace
components within that source, and the fixed capital cost of the new
components exceed 50 percent of the fixed capital cost of a comparable
entirely new source, then the owner or operator must notify the EPA of
the proposed replacements.  This notification must be made at least 60
days before construction of the replacement is commenced, and must
                                   5-3

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include the information specified in 40 CFR 60.15(d).   After the
effective date of a permit program under Title V of the CAAA, no
reconstruction of a major source may be made until  such reconstruction
is approved by the EPA (or the State).
      There is no offset provision for reconstruction  as there is for
modification.  Therefore, any reconstruction must meet the MACT emission
limitation for new sources.
5.2   APPLICATION TO AEROSPACE MANUFACTURING AND REWORK FACILITIES
      Aerospace manufacturing and rework encompasses numerous
operations, and changes in any of these operations  may result in a
modification as defined in Section 112(a)(5) of the CAAA or a
reconstruction as defined in 40 CFR 60.15.   As such, a description of
the modification and reconstruction that may occur for each process is
beyond the scope of this section.  However, several general changes that
may occur at aerospace manufacturing and rework facilities are presented
bel ow.
5.2.1  Sorav Booths
      The addition of spray booths for coating application will
generally increase emissions due to an increase in  coating production
capacity, even though the plant manufacturing capacity has not changed.
For example, a facility that is near plant  manufacturing capacity may be
taxing the coating capacity of the existing spray booths.   The facility
then adds new spray booths to relieve this  production  bottleneck.  The
emissions will then increase on a mass per  time basis  (kg/hr), since
more coating can be accomplished per hour with the additional spray
booths than before the modification.
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5.2.2  Addition of a New Operation
      An aerospace facility may add an operation not previously
performed at that facility, resulting in an increase in emissions.  The
addition of the operation may be due to the requirements of a new
product line, or bringing in-house an operation previously performed by
a subcontractor.  Examples of these operations include chemical milling,
coating removal, metal finishing, and composite processing.
      The changes necessary to add one of these operations will
typically be considered a modification.  However, extensive changes
necessary for adding a process such as coating removal for large
aircraft (e.g., construction of a hanger and ventilation system, spray
equipment, and waste treatment) may approach the criteria for
classification as reconstruction.
5.2.3  Addition of a New Product Line
      The addition of a new product line generally involves extensive
changes throughout an existing facility.  In addition to modifications
described in Sections 5.2.1 and 5.2.2, the layout of all or part of the
facility may change.  This may involve the relocation or construction of
raw material storage, process operations, offices, and utilities.
      A new product line may be added at a facility under one of two
scenarios.  In the first scenario, the new product line is added to the
existing product lines already being manufactured at the facility.  This
will usually involve the most extensive physical changes to the facility
and will most likely increase emissions.  Depending on the extent of the
changes that are made to the existing product lines, this may qualify as
reconstruction.  The second scenario involves an old product line being
replaced by the new product line.  In this case, the physical changes to
                                   5-5

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the facility may be minor since manufacturing floor space and process
capacity will be available from the elimination of the old product line.
This type of change may be considered a modification rather than a
reconstruction.
                                   5-6

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                            6.0  MODEL  PLANTS

      This chapter describes the model  plants for the aerospace
manufacturing and rework industry.  The model plants will be used to
assess the environmental, energy,  cost, and economic impacts of the
proposed national emission standard for hazardous air pollutants
(NESHAP).
6.1   MODEL PLANTS
      Eleven model plants were developed to characterize facilities in
the aerospace manufacturing and rework industry.  The model plant
parameters were developed primarily from responses to Section 114
questionnaires sent to aerospace manufacturing and rework facilities,
and site visit questionnaires.  Table 6-1 lists the aerospace
manufacturing and rework facilities that received the initial Section
114 questionnaires and the facilities that provided voluntary responses,
Table 6-2 lists the aerospace manufacturing and rework facilities that
received the Section 114 questionnaire on emissions from waste and
wastewater operations, storage tanks, and inorganic emissions from
depainting and coating application operations.  Site visits were
conducted at the facilities listed in Table 6-3.
      The model plants developed are presented in Table 6-4.  The model
plants were based primarily on three parameters:  (I) market segment
(commercial versus military), (2)  type of work performed [original
equipment manufacture (OEM) versus rework], and (3) the size of the
                                   6-1

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                         TABLE 6-1

AEROSPACE MANUFACTURING AND REWORK FACILITIES THAT RECEIVED
                SECTION  114 QUESTIONNAIRES
Company
American Airlines8
Boeing
Delta Air Lines9
Facility
Tulsa Maintenance and
Tulsa, OK
Alliance Maintenance
Engineering Center -
Base - Ft. Worth, TX
Line Maintenance Facilities
- Chicago, 11
- Dallas, TX
- New York , NY (2 facilities)
- Los Angeles, CA
- San Francisco, CA
Auburn, WA
Development Center -
Seattle, WA
Everett, WA
Kent Space Center - Kent, WA
Macon, GA
North Boeing Field -
Seattle, WA
Oakridge, TN
Oxbow - Seattle, WA
Philadelphia - Ridley
Park, PA
Plant 2 - Seattle, WA
Portland - Gresham, OR
Renton, WA
Robbins - Kent, WA
South Park - Seattle,
WA
Thompson Site - Seattle, VIA
Wichita, KS
Technical Operations
Center - Atlanta, GA
                            6-2

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TABLE 6-1 (Continued)
Company
General Dynamics
Grumman
Lockheed
Martin Marietta
McDonnell Douglas
Facility
Air Defense - Pomona, CA
Convair - San Diego, CA
Fort Worth, TX
Fort Worth/Abilene - Abilene, TX
Space Systems - San Diego, CA
Bethpage, NY
Calverton, NY
Glen Arm, MD
Houston - Webster, TX
Millidgeville, GA
St. Augustine, FL
Stuart, FL
Advanced Development - Palmdale, CA
Aeromod Center - Greenville, SC
Aeronautical Systems - Marietta, GA
Aeromod Center - Tucson, AZ
Aircraft Services - Ontario, CA
Missiles and Space - Sunnyvale, CA
Space Launch Systems - Cape Canaveral , FL
Aero and Naval Systems - Baltimore, MD
Michoud Assembly - New Orleans, LA
Sand Lake Facility - Orlando, FL
Payload Fairing Processing Facility -
Vandenburg Air Force Base, CA
Waterton - Littleton, CO
Columbus, OH
Helicopter Company - Culver City, CA
Space Systems - Huntington Beach, CA
Cl Facility - Long Beach, CA
          6-3

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TABLE 6-1 (Continued)
Company
McDonnell Douglas
Northrop
Robins Air Force Base
Rohr
Facility
Macon, GA
Melbourne, FL
Helicopter Company - Mesa, AZ
Space Systems -
Pueblo, CO
St. Charles, MO
MDC - St. Louis
Salt Lake City,
Florida Missile
, MO
UT
Production - Titusville, FL
Torrance, CA
Tulsa, OK
AG/AF - Hawthorne, CA
Site 4 B-2 Divi
B-2 Division -
D-2 - Compton,
East Complex -
sion - Palmdale, CA
Pico Rivera, CA
CA
Hawthorne, CA
Hawthorne-Aircraft/NAD - Hawthorne, CA
K-l/K-3 - Torrance, CA
K-4 - Torrance,
K-6 - Torrance,
K-8 - Torrance,
West Complex -
Y-12 - Anaheim,
CA
CA
CA
El Segundo, CA
CA
Robins Air Force Base - Warner Robins, GA
Arlington - Riverside, CA
Moreno Valley,
CA
Riverside, CA
          6-4

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                       TABLE 6-1 (Concluded)
Company
Trans World Airlines8
TRWa
United
Airlines
USAir
Facility
Ground Operations Center - Kansas City,
MO
Space Park Facility - Redondo Beach, CA
San Francisco, CA
Winston Salem, NC
Voluntary submittals
                                 6-5

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                         TABLE 6-2
AEROSPACE MANUFACTURING AND REWORK FACILITIES THAT RECEIVED
    SECTION  114 QUESTIONNAIRES ON WASTE, WASTEWATER, AND
                    INORGANIC EMISSIONS
Company
Beech Aircraft Corp.
Boeing
Cherry Point Naval
Aviation Depot
Edward Air Force Base8
Eg! in Air Force Base8
Hill Air Force Base3
Kaman Aerospace Corp.
Facility
Andover, KS
Salina, KS
Wichita, KS
Auburn, WA
Development Center - Seattle, WA
Everett, WA
Kent Space Center - Kent, WA
Macon, GA
North Boeing Field - Seattle, WA
Oakridge, TN
Philadelphia - Ridley Park, PA
Plant 2 - Seattle, WA
Portland - Gresham, OR
Renton, WA
Robbins - Kent, WA
Thompson Site - Seattle, WA
Wichita, KS
Cherry Point AFB, NC
Edwards AFB, CA
Eg! in AFB, NJ
Hill AFB, UT
81 cornfield, CT
Gilman, CT
Moosup, CT
                            6-6

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                         TABLE 6-2 (Concluded)
Company
Kaman Aerospace Corp.
(Continued)
Kirtland Air Force
Base8
Lockheed
Malmstrom Air Force
Base3
McDonnell Douglas
McGuire Air Force Base3
PEMCO Aeroplex
Tinker Air Force Base
United Airlines
Facility
Jacksonville, FL
Kirtland AFB, NM
Advanced Development - Palmdale, CA
Aeromod Center - Tucson, AZ
Aircraft Services - Ontario, CA
Lockheed Fort Worth - Fort Worth, TX
Missiles and Space - Sunnyvale, CA
Malmstrom AFB - Great Falls, MT
Helicopter Company - Culver City, CA
Space Systems - Huntington Beach, CA
Douglas - Long Beach, CA
Melbourne, AR
Helicopter Company - Mesa, AZ
St. Charles, MO
MDC - St. Louis, MO
Salt Lake City, UT
Florida Missile Production - Titusville, FL
Tulsa, OK
McGuire AFB, NJ
Birmingham, AL
Tinker Air Force Base, OK
San Francisco, CA
Oakland, CA
3 Voluntary submittals
                                   6-7

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                  TABLE 6-3
            SITE VISIT FACILITIES
Beech Aircraft - Wichita, KS
Boeing - Seattle, WA
Caspian - San Diego, CA
Cessna - Wichita, KS
Delta Air Lines - Atlanta, GA
General Dynamics - Pomona, CA
Hughes - Fullerton & El Segundo, CA	
Hunting Air - Peachtree City, GA	
LearJet - Wichita, KS	
Lockheed - Marietta, GA	
Maxwell Laboratories - San Diego, CA	
Naval Air Station Alameda - Alameda, CA
Northrop - Palmdale & El Segundo, CA	
Robins Air Force Base - Warner Robins, GA
Trans World Airlines - Kansas City, MO
United Airlines - San Francisco, CA	
USAir - Winston Salem, NC	
                     6-8

-------
                                TABLE  6-4

                        MODEL PLANT DESCRIPTIONS
Model Plant
1
2
3
4
5
6
7
8
9
10
11
Market Segment
Commercial
Commercial
Commercial
Commercial
Commercial
Military
Military
Military
Military
Military
Military
Work Type
OEM
OEM
OEM
Rework
Rework
OEM
OEM
OEM
Rework
Rework
Rework
Size8
Small
Medium
Large
Small
Medium
Small
Medium
Large
Small
Medium
Large
8 Small
  Medium
         < 1,000 employees
         1,000 to 9,999 employees
Large  * 10,000+ employees
                                   6-9

-------
facility (small, medium, or large) in terms of the number of employees.
There are no large commercial/rework facilities based on the Section 114
questionnaire responses and information obtained during site visits.
Secondary model plant parameters, as presented in Section 6.1.2, were
then used to further refine the development of the model plants.
Parameters specific to each process (e.g., tank size, number of spray
guns) are detailed in the cost and environmental impact memos.
6.1.1  Primary Model Plant Parameters
      6.1.1.1  Market Segment.  Different model plants were developed
for the commercial and military market segments because of differences
in performance requirements or specifications.  These differences result
in the use of a different mix of processes and coatings in the
commercial and military market segments.
      6.1.1.2  Work Type.  The type of work (OEM versus rework)
                                          •
performed at the facility was selected as a defining parameter for model
plants because there are a few major HAP emitting processes that are
nearly exclusive to each type of work.  The principle of these are
chemical milling and depainting.
      The chemical milling process is used primarily at OEM facilities
and consists of two steps:  (1) the application and subsequent drying of
a maskant to the surface of the parts to be milled and  (2) the chemical
milling.  Rework facilities do not typically perform chemical milling to
any large extent, other than in the manufacture of some replacement
parts (e.g., outer skin panels).
      Depainting is performed primarily at rework facilities where the
entire outer surface of the aircraft is stripped.  This operation
presents air emission and waste disposal problems unique to rework
                                  6-10

-------
facilities due to the large hangar in which the stripping is performed.
While OEM facilities perform paint removal operations, (e.g., stripping
of paint from small parts or assemblies) they are not typically of the
scale seen at rework facilities.
      6.1.1.3  Size.  Three sizes (small, medium, and large) have been
defined for the model plants.  The sizes have been defined based on
number of employees.  Figure 6-1 shows the distribution of aerospace
manufacturing and rework facilities by number of employees as reported
in the Section 114 responses, and Figure 6-2 shows the nationwide
distribution of facilities by number of employees as reported by the
Bureau of the Census.
      Small model plants have been defined as having less than 1,000
employees.  Medium model plants have 1,000 to 9,999 employees.  Large
model plants have 10,000 or more employees.  This reflects the makeup of
the industry where there are a few large facilities and more numerous
medium and small facilities.
      Although three model plant sizes have been defined, no data have
been found that suggest there are commercial rework facilities in the
large category.  Therefore, only small and medium commercial rework
model plants were developed.
6.1.2  Secondary Model Plant Parameters
      The model plants were defined by three primary parameters (i.e.,
market segment, work type, and size) as presented in Section 6.1.1.  In
order to further define the model plants for the purpose of conducting
the impact analyses and determining baseline emissions, secondary
parameters were also developed.
                                  6-11

-------
                         FIGURE 6-1


     DISTRIBUTION OF AEROSPACE FACILITIES BY


                NUMBER OF EMPLOYEES
  20
P 15
3


i
fe 10
o
&
w
                                  17
                            15
10
   0
                                        15
       1-100         501-1000       2501-5000       7501-10000


             101-500       1001-2500      5001-7500        > 10000


                      NUMBER OF EMPLOYEES
SOURCE: SECTION 114 QUESTIONNAIRE RESPONSES
                               6-12

-------
                          FIGURE 6-2
   DISTRIBUTION OF AEROSPACE MANUFACTURING
        FACILITIES BY NUMBER OF EMPLOYEES
  800
  700
c3
| 600

D 500
£
fe 400
O
  300

  200

  100

   0

SOURCE
                  625
                       •976-
                             .m.
                                   206
                                               229
                                         128
1-4
5-9
             1049  20-49  50-99 100-249 250-499 500-999  >1000
                 NUMBER OF EMPLOYEES
U.S. DEPARTMENT OF COMMERCE
BUREAU OF THE CENSUS
COUNTY BUSINESS PATTERNS 1989
                               6-13

-------
      6.1.2.1  Process Profile.  The responses to the Section 114 and
site visit questionnaires were used to determine the similarities
between each facility classification (i.e.,  commercial/OEM,
commercial/rework, military/OEM, and military/rework) on the basis of
processes used at the facility.  Thirteen operations covering aerospace
manufacturing and rework were developed as presented in Section 3.2.
However, only the processes regulated under the proposed rule will be
discussed in this chapter.  Using the facility classification and number
of employees as reported for each facility in the Section 114 responses,
a "process profile" was developed for each model plant.  These process
profiles are presented in Table 6-5.
      Medium and large commercial/OEM facilities tend to have all
operations except depainting.  Small commercial/OEM facilities, however,
do not have maskant application, because these processes are typically
beyond the scope of their operations.  Small, medium, and large
military/OEM facilities follow these same trends.
      Based on survey data, maskant operations are generally not found
at either commercial or military/rework facilities, regardless of size.
Rework facilities typically perform all other operations.
                                  6-14

-------
                                TABLE  6-5
                      MODEL PLANT PROCESS PROFILES
Process
Depainting
Chemical Milling
Maskant
Spray Gun Cleaning
Hand-Wipe Cleaning
Primers and
Topcoats
Model Plants
Commercial
OEM
S


X
X
X
M

X
X
X
X
L

X
X
X
X
Commercial
Rework
S
X

X
X
X
M
X

X
X
X
Military
OEM
S


X
X
X
M

X
X
X
X
L

X
X
X
X
Military
Rework
S
X

X
X
X
M
X

X
X
X
L
X

X
X
X
X = Process is performed at the model plant.
                                  6-15

-------
               7.0  NATIONWIDE BASELINE HAP EMISSIONS AND
                          ENVIRONMENTAL  IMPACTS
7.1   INTRODUCTION
      The purpose of this chapter is to present the nationwide baseline
HAP emission estimates.  Additionally, this chapter presents the air,
water, energy, and solid waste impacts associated with compliance with
the proposed standards.
7.2   NATIONWIDE BASELINE HAP EMISSIONS
      The nationwide baseline HAP emissions presented in Table 7-1 were
based on the baseline HAP emissions calculated in the environmental
impact memos (see Appendix A).  These HAP emissions were then multiplied
by the number of model plant associated with each process to obtain the
nationwide HAP emission estimates.  As presented in Chapter 6, the
number of model plants associated with each process differed.  The HAP
emissions from spray gun cleaning and hand-wipe cleaning are applicable
to all model plants.  The HAP emissions from primer and topcoat
application also are applicable to all model plants, but differ between
commercial and military market segments.  In addition, the HAP emissions
from chemical milling maskant application and depainting are only
applicable to OEM and rework model plants, respectively.
7.3   ENVIRONMENTAL IMPACTS
      Environmental impacts, defined as the air, water, energy, and
solid waste effects of being in compliance with the proposed standard,
were based on the model plants presented in Chapter 6.  Tables 7-2
                                   7-1

-------
through 7-5 present the Impacts on both a model  plant and nationwide
basis.  The nationwide impacts are based on a combination of facility
impacts for the model  plants and the estimated number of operations
nationwide of each size model plant.
      The bases for the impact estimates for each of the processes are
presented in environmental impact memos.  Impact information was
obtained from major vendors or from Section 114 questionnaire responses
from aerospace manufacturing and rework facilities.  Telephone calls
were also used to clarify data and to obtain additional data.  The model
plant parameters presented in Chapter 6 were used to ensure a common
basis for the estimates.
      Some processes have multiple options to comply with the proposed
standards.  The environmental impacts used in the tables are those
associated with the options that have the lowest cost impact.  For
depainting, the impacts associated with the use of non-HAP chemical
strippers are used for both commercial and military rework model plants.
For chemical milling maskant application, the impacts associated with
the use of waterborne maskant application are used for medium model
plants, and the impacts for solvent based maskant application in
conjunction with a carbon adsorber are used for large model plants.
There is only one option for both spray gun cleaning and hand-wipe
cleaning, and the associated impacts are used for all model plants.  The
impacts used for primer and topcoat application are specific to military
and commercial model plants.
      The air, wastewater, energy, and solid waste impacts calculated
for controlling inorganic HAP emissions from primer and topcoat
application and depainting operations were calculated on a nationwide
                                   7-2

-------
basis rather than on a model plant basis due to the data that was
available.  These values are presented in Tables 7-2B, 7-4B, and 7-5B.
The total impacts are then presented in Tables 7-2C, 7-4C, and 7-5C.
There is no wastewater generation associated with the inorganic controls
and, therefore, there is only one table for wastewater (Table 7-3).
      The data presented in this chapter is only for existing
facilities.  For the aerospace industry, no net growth is expected over
the next five years; therefore, no new facilities are anticipated during
this period.
                                  7-3

-------

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                                                7-8

-------
                                 TABLE 7-5B
SOLID WASTE GENERATION WHILE CONTROLLING INORGANIC HAP EMISSIONS (TONS/YEAR)
Process
Depainting
Primers and Topcoats
TOTAL NATIONWIDE
(INORGANIC)
Nationwide Model Plants
Small
N/A
641
Medium
N/A
574
Large
N/A
29
1,244
                                 TABLE 7-5C
                  TOTAL SOLID WASTE GENERATION (TONS/YEAR)
            TOTAL NATIONWIDE
-10,670
                                    7-9

-------
                 8.0   COST ANALYSIS OF CONTROL  OPTIONS

8.1   INTRODUCTION
      This chapter presents the capital  costs and annualized control
costs, including recovery credits, attributable to compliance with the
proposed standards that have been estimated for existing facilities.
8.2  ANNUAL COSTS
      Annual costs were based on the application of the control options
to the model plants presented in Chapter 6.  Tables 8-1 through 8-4
                         •
present the annual  costs by model plant.   These tables also present the
nationwide annual cost impact by model  plant.  Table 8-5 presents the
total nationwide annual costs.  The nationwide annual costs are based on
a combination of facility costs for the model plants and the estimated
number of operations nationwide of each size model plant.
      The bases for the cost estimates for each of the processes are
presented in cost impact memos (see Appendix B).  Cost information was
obtained from major vendors of the control option techniques or from
Section 114 questionnaire responses from aerospace facilities.
Telephone calls were also used to clarify data and to obtain additional
data.  The model plant parameters presented in Chapter 6 and in the
impact memos helped to ensure a common basis for the cost estimates.
All cost data presented in this chapter are in 1992 dollars.
                                   8-1

-------
      Some processes have multiple options to comply with the proposed
standards.  The costs used in the tables are the lowest costs available
for each process.   For depainting, the costs associated with the use of
non-HAP chemical strippers are used for both commercial and military
rework model plants.  For chemical milling maskant application, the
costs associated with the use of waterborne maskant application are used
for all medium model plants, and the costs associated with the use of
solvent-based maskant application in conjunction with a carbon adsorber
are used for large model plants.  There is only one cost option for
spray gun cleaning and hand-wipe cleaning, and this cost is used for all
model plants.  The costs used for primer and topcoat application are
specific to military and commercial model plants.
      Due to the available data, the costs calculated for controlling
inorganic emissions from primer and topcoat application and depainting
operations were calculated on a nationwide basis.  Therefore, these
values are presented only in the summary table, Table 8-5.
      The data presented in this chapter are only for existing
facilities.  For the aerospace industry, no net growth is expected over
the next five years; therefore, no new facilities are anticipated during
            \
this period.
8.3  CAPITAL COSTS
      Capital costs would be incurred with the implementation of control
measures for chemical milling maskants (both solvent-based chemical
milling maskants with a carbon adsorber and waterborne chemical milling
maskants}, dry media blasting for depainting, spray gun cleaning, and
control of inorganic HAP emissions from primer, topcoat, and depainting
operations.  The nationwide capital costs listed below represent the
                                   8-2

-------
maximum costs that would be incurred assuming that all affected sources
implemented the specific control option.
      For carbon adsorbers used in conjunction with solvent-based
chemical milling maskants, the nationwide capital cost is estimated to
be $500 million, and for waterborne chemical milling maskants it is
estimated to be $289 million.  The implementation of dry media blasting
systems for depainting would require a nationwide capital cost of $2.8
billion.  It should be noted that other control measures exist for
depainting other than dry media blasting, such as chemical strippers
that do not contain organic HAPs, that require no capital investment.
Selection of chemical strippers that do not contain organic HAPs by all
affected sources instead of dry media blasting would decrease the total
nationwide capital investment by approximately 82 percent.  The control
measures would also require capital costs for high transfer efficiency
application equipment and spray gun cleaning equipment totalling $130
million and $10 million, respectively.  The control of inorganic HAP
emissions from primer and topcoat application operations would require
the installation of spray booths and filter systems at a capital cost of
$13 million.  The control of inorganic HAP emissions from blast
depainting operations would require the installation of particulate
filtration systems such as baghouses at a capital cost of $54.5 million.
Total nationwide capital costs range from $3.3 billion to $3.5 billion,
depending on which chemical milling maskant control option is used.
                                   8-3

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                               TABLE 8-1



                    CONTROL  COSTS  FOR COMMERCIAL  OEM8
Process
Depainting
Chemical Milling Maskant
Spray Gun Cleaning
Hand-Wipe Cleaning
Primers and Topcoats
TOTAL FOR ONE FACILITY
NUMBER OF FACILITIES
TOTAL FOR ALL FACILITIES
TOTAL FOR COMMERCIAL
REWORK
Total Annual i zed Costs
Small
N/A
N/A
-16,720
7,030
-36,830
-46,520
440
-20,468,800
Medium
N/A
106,680
-22,100
3,510
-67,350
20,740
20
414,800
Large
N/A
135,540
-28,000
-9,260
-520,600
-422,320
6
-2,533,920
-22,587,920
Negative values represent a cost savings to the model plant.
                                   8-4

-------
                            TABLE 8-2



               CONTROL COSTS FOR COMMERCIAL REWORK8
Process
Depainting
Chemical Milling Maskant
Spray Gun Cleaning
Hand-Wipe Cleaning
Primers and Topcoats
TOTAL FOR ONE FACILITY
NUMBER OF FACILITIES
TOTAL FOR ALL FACILITIES
TOTAL FOR COMMERCIAL
REWORK
Total Annual i zed Costs
Small
-7,200
N/A
-16,720
7,030
-36,830
-53,720
404
-21,702,880
Medium
-23,590
N/A
-22,100
3,510
-67,350
-109,530
525
-57,503,250
Large
N/A
N/A
-28,000
-9,260
-520,600
-557,860
0
0
-79,206,130
Negative values represent a cost savings to the model plant.
                               8-5

-------
                            TABLE 8-3



                  CONTROL  COSTS  FOR  MILITARY  OEM8
Process
Depainting
Chemical Milling Maskant
Spray Gun Cleaning
Hand-Wipe Cleaning
Primers and Topcoats
TOTAL FOR ONE FACILITY
NUMBER OF FACILITIES
TOTAL FOR ALL FACILITIES
TOTAL FOR MILITARY OEM
Total Annual 1 zed Costs
Small
N/A
N/A
-16,720
7,030
-8,680
-18,370
332
-6,098,840
Medium
N/A
106,680
-22,100
3,510
-12,450
75,640
38
2,874,320
Large
N/A
135,540
-28,000
-9,260
-90,830
7,450
7
52,150
-3,172,370
Negative values represent a cost savings to the model plant
                                8-6

-------
                            TABLE 8-4
                CONTROL COSTS FOR MILITARY REWORK8
Process
Depainting
Chemical Milling Maskant
Spray Gun Cleaning
Hand-Wipe Cleaning
Primers and Topcoats
TOTAL FOR ONE FACILITY
NUMBER OF FACILITIES
TOTAL FOR ALL FACILITIES
TOTAL FOR MILITARY
REWORK
Total Annuali zed Costs
Small
-7,200
N/A
-16,720
7,030
-8,680
-25,570
142
-3,630,940
Medium
-23,590
106,680
-22,100
3,510
-12,450
52,050
950
49,447,500
Large
-23,590
135,540
-28,000
-9,260
-90,830
-16,1400
5
-80,700
45,735,860
Negative values represent a cost savings to the model plant.
                               8-7

-------
                            TABLE 8-5
                     SUMMARY OF  CONTROL  COSTS*
Model Plant Type
Commercial /OEM
Commercial /Rework
Military/OEM
Military/Rework
Sub-Total
Inorganics - Primers and Topcoats
Inorganics - Depainting
TOTAL
Control Costs
-22,587,920
-79,206,130
-3,172,370
45,735,860
-59,230,560
2,287,380
7,760,600
-49,182,580
Negative values represent a cost savings.
                                8-8

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                          9.0   ECONOMIC  IMPACTS

9.1   INDUSTRY PROFILE
9.1.1  Introduction
      The Clean Air Act Amendments of 1990 mandate the establishment of
emission standards for major sources of hazardous air pollutants (HAPs)
and the promulgation of regulations for the purpose of achieving these
standards.  By definition, any stationary source or group of sources
that emits 10 tons or more of a hazardous air pollutant or 25 tons or
more of a combination of hazardous air pollutants per year is deemed a
"major source" and will be subject to regulation.
      HAPs are emitted by coatings and solvents used in the aerospace
industry and, as such, aerospace producers will  be candidates for
regulation as major sources.  In an effort to evaluate the impact of the
regulation on the industry, the current state of the aerospace industry
must first be established.  For this purpose, various market
characteristics have been identified, the relevant ones being those that
may exhibit some change after the regulation is promulgated.
      Given the organization of aerospace production, the important
supply-side variables that are likely to be affected by the potential
regulation are output, employment, the number and size of establishments
(economic unit),1 profit rates,  industry growth,  plant and equipment
expenditures, and nei exports.  Demand-side variables that will be
affected by this potential regulation are revenue from the sale of
domestically produced aerospace products and expenditures on imports of
                                   9-1

-------
aerospace products.  In the long run, the very organization of
production could change.
      In both the original equipment manufacture (OEM) and the repair
and maintenance (rework) of aerospace products, coatings and solvents
that emit HAPs are used.  The associated processes include machining,
cleaning, maskant application, chemical milling, assembling, bonding,
surface preparation, coating application, and stripping, to name a
few.2  To the degree permitted by cost considerations  and technological
development, the industry will respond to regulation by adopting
alternative materials (coatings and solvents), changing the methods of
production, or using add-on controls.
      The Standard Industrial Classification (SIC) codes that report
data on original equipment manufacture in the aerospace industry are:
SIC 3721, Aircraft; SIC 3724, Aircraft Engines and Engine Parts; SIC
3728, Aircraft Parts and Auxiliary Equipment, Not Elsewhere Classified
(NEC); SIC 3761, Guided Missiles and Space Vehicles; SIC 3764, Guided
Missiles and Space Vehicles/Propulsion Units and Propulsion Unit Parts;
SIC 3769, Guided Missiles and Space Vehicle Parts and Auxiliary
Equipment, NEC.  SIC 4581, Airports, Flying Fields and Airport Terminal
Services is also of interest in that it captures rework, but it will not
be possible to separate aerospace output from the total output reported
in this SIC code.
      Independently owned rework establishments as well as hangars  in
which airlines perform rework on aircraft that they own or lease may be
affected by the potential regulation.
                                   9-2

-------
      Indirectly affected by the regulation will be establishments in
SIC 2851, Paints, Varnishes, Lacquers, Enamels, and Allied Products; and
in SIC 2891, Adhesives and Sealants.
9.1.2  Industry Overview
      The SIC codes that will be directly affected by the regulation are
collectively referred to as the aerospace industry, represented
schematically by Figure 9-1.  The diagram depicts both the use of
coatings and solvents and the specialization of establishments in the
aerospace industry.  Regarding the former, the quantities and
combinations of coatings and solvents used in the industry differ
according to the intended use of the product (military versus
commercial) as well as the type of work being performed (original
equipment manufacture versus rework).  The shaded areas represent
coatings and solvents common to both military and commercial products.
Some coatings and solvents are common to original equipment production
and to rework as indicated by the broken circle.
      Establishments in the aerospace industry produce specialized
output and perform specialized tasks.  Broadly, some establishments
produce original equipment exclusively for military purposes and others
produce for commercial purposes.  A few establishments serve both the
commercial and the military segments of the market as indicated by the
intersection of the ellipses in Figure 9-1.  Similarly, there are
establishments that engage exclusively in rework either on military or
commercial equipment or both.  Finally, a certain amount of "in factory"
rework is done by OEMs on their own equipment.
      The demand for aerospace products is derived from the demand for
                                                                  •
final goods such as air travel (business and leisure), defense,
                                   9-3

-------
         Figure  9-1
    Aerospace  Industry
  Military
Commercial
OEM — Original  Equipment Manufactures
RW - Rework
              9-4

-------
Information, and national security.  As such,  the demand for any
aerospace product is a function of its own price, the prices of
substitutes, the prices of the final  goods,  and national income.  The
demand for rework on aerospace products is additionally a function of
the age and intensity of usage of the existing products as well as the
cost of rework.  As the stock of durable original equipment increases,
the demand for rework will increase,  given the costliness and length of
time required to produce aerospace products.
      Table 9-1 gives an indication of the various products of the
industry, their end uses, and major original  equipment manufacturers.
It makes clear both the variety of the products in the industry as well
as the specialization of producers.
      Manufacturing and assembling of complete units in the aerospace
industry take place in a complex manner.  This process involves prime
contractors and several tiers of subcontractors:
      •     Prime Contractors      —     Design (develop) and assemble
                                          or manufacture complete units.
      •     1st Tier Subcontractors —     Do major assembly and/or
                                          manufacture of sections of
                                          air/space craft without
                                          designing or assembling
                                          complete units.
      •     2nd Tier Subcontractors—     Make various subassemblies and
                                          sections.
      •     3rd Tier Subcontractors —     Produce machined components
                                          and sub-assemblies.
      •     4th Tier Subcontractors—     Specialize in the production
                                          of particular components and
                                          in specific processes.

      Corresponding to the designation "prime contractor" are the SIC
codes 3721, 3724, 3751, and 3764.  Both first and second tier
                                   9-5

-------
                              TABLE 9-1
                 PRODUCTS AND SELECTED MANUFACTURERS
                    IN THE U.S.  AEROSPACE INDUSTRY
            Product
       Manufacturer/Developer
SIC 3721 Aircraft
  Military Aircraft
    Attack

    Bombers
    Electronic Warfare
    Fighters

    Reconnaissance
    Observation
    Patrol ASW
    Antisubmarine
    Early Warning
    Cargo/Transport/
    Refueling
    Training

    Utility
    Research/Test Bed
McDonnell Douglas
LTV Aircraft
Boeing
Grumman Aerospace
McDonnell Douglas
Northrop
Grumman Aerospace
Lockheed
RI/NAA
Lockheed
Lockheed
Boeing
Lockheed Aeronautical Systems Co.
McDonnell Douglas
Rl/Colombus
Beech Aircraft Corp.
Beech Aircraft Corp.
Boeing	
  Helicopters
Bell Helicopter Textron
Boeing Helicopter
McDonnell Douglas Helicopter Co.
Sikorsky Aircraft United Technologies
Corp.	   	
  Commercial Passenger
  Aircraft
Beech Aircraft Corp.
Boeing
Fairchild Aircraft Corp.
Lockheed Aeronautical Systems Co.
McDonnell Douglas	
                                  9-6

-------
                        TABLE 9-1 (CONTINUED)
            Product
       Manufacturer/Developer
SIC 3721 Aircraft (Cont.)
  Turbine Powered
  Business Aircraft
Beech Aircraft Corp.
Cessna Aircraft Co.
Learjet Inc.	
  General Aviation
  Aircraft
Beech Aircraft Corp.
Maula Air, Inc.
Piper Aircraft Corp.
Taylor Aircraft Corp.
SIC 3724, Aircraft Engines
  Gas Turbine Engines
Allied-Signal Garrett Engine
Div.
General Electric Co.
General Electric Aircraft Engines
General Motors Allison Gas Turbine
Div.
Teledyne CAE
Textron Lycoming Stratford Div.
United Technologies Pratt & Whitney
Will jams Int. Corp.	
  Reciprocating Engines
Textron Lycoming
Teledyne Continental Motors
SIC 3761 Guided Missiles
  and Space Craft	
  Missiles

    Air-to-Air


    Air-to-Surface

    Surface-to-Air


    Surface-to-Surface
Hughes/Raytheon
Loral/Raytheon

Hughes

Ford Aerospace
General Dynamics/Pomona

AFLC Hill Air Force Base
Lockheed MSC
                                 9-7

-------
                         TABLE 9-1 (CONTINUED)
Product
SIC 3761 Guided Missiles
and Space Craft (Cont.)
Spacecraft
SIC 3764 Propulsion Units
Basic Vehicles
Upper Stages
Manuf acturer/Devel oper

Rockwell International
Martin Marietta
General Electric/Goddard S.F.C.
Hughes
General Electric
TRW
Lockheed

Martin Marietta
General Dynamics/Space Systems
McDonnell Douglas
General Dynamics/Space Systems
Boeing
Orbital Sciences
Source:  Aviation Week and Space Technology.  March 16,  1992  pp.  94-115.
                                  9-8

-------
subcontractors correspond to SICs 3728 and 3769.  Third tier
subcontractors are included in SIC 3599, as are fourth tier
subcontractors who may be regarded as subcontractors to the third tier
subcontractors.
      With these different layers of subcontracting, the industry cannot
be described as comprising vertically integrated firms.  Even the
production of components of complete units, though classified as
distinct SIC codes, involves a sufficient degree of subcontracting to
preclude the economies associated with vertical integration.  Such
subcontracting allows firms to specialize in order to meet the high
precision requirements of the industry.
9.1.3  Original Equipment Manufacture
      9.1.3.1  Market Structure.  Table 9-2 shows that in 1988 there
were 1,762 OEM establishments in the aerospace industry.  Of these, 453
were engaged in the manufacture of aircraft engines and engine parts
(SIC 3724), and 1013 were engaged in the manufacture of aircraft parts
and auxiliary equipment (SIC 3728).  Therefore, 83.2 percent of all the
OEM establishments in the aerospace industry were engaged in production
at these two SIC levels.
      Additionally, Table 9-2 also shows the number of companies by SIC
code.  It indicates that, not only were establishments concentrated in
SICs 3724 and 3728, as discussed in the preceding paragraph, but that
production took place, to a large extent, in independently owned
establishments (i.e., single-establishment companies).  (This will prove
to be an important consideration in the Economic Impact Analysis.
Section 9.2.)
                                   9-9

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      Moreover,  there is much less vertical  integration in the
production of aircraft than in the production of guided missiles and
space vehicles:   only 9.6 percent of all  the establishments that engage
in aircraft production (SIC 372) manufacture or assemble complete
aircraft (SIC 3721), compared with 28.4 percent of the establishments in
SIC 376 that manufacture complete guided missiles and space vehicles
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observation.
      In 1988, most of the establishments in the aerospace industry were
small, employing less than 1,000 production  workers.  For this period,
about 95.4 percent of all the establishments involved in aircraft
production (SIC 372) and 73.0 percent of the establishments engaged in
the production of missiles and space vehicles (SIC 376) were small.
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employ 10,000 persons or more, manufactured  aircraft engines and engine
parts (SIC 3724), 20 percent specialized in  aircraft parts and auxiliary
equipment (SIC 3728), and 67 percent engaged in the manufacture or
assembly of complete aircraft.  In comparison, all of the large
establishments in SIC 376 produced complete  units (SIC 3761).  It is
reasonable to infer then, that there are greater economies (or less
diseconomies) of scale associated with the manufacture of missiles and
spacecraft than the manufacture of aircraft.
      Table 9-3 presents, for each SIC Code, the distribution of revenue
by employment-size class.  While 93.6 percent of all establishments are
small (as calculated from Table 9-2), it can be seen from Table 9-3
that, for each SIC code, revenue is concentrated in large facilities and
                                  9-11

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medium facilities, the latter employing between 1,000 and 9,999 persons.
This is especially the case for SICs 3721 and 3761 because small,
medium, and large establishments belonging to the same SIC code engage
in different activities, with the small establishments engaging in
activities that contribute the least "value-added."  In SIC 3721, for
example, there are establishments of different sizes that manufacture or
assemble complete aircraft; modify, convert, or overhaul previously
accepted aircraft; engage in research and development; and provide
aeronautical services on complete aircraft.  These establishments will
therefore contribute different amounts of value added to the product,
with activities (such as research and development) that generate the
least value added tending to employ less than 1000 production workers.
Likewise, the preponderance of small establishments in SIC 3761 is
associated with a concentration of revenue in the few large
establishments because the small establishments engage in research and
development while the large establishments also manufacture complete
missiles and spacecraft.3
      It can be seen from Table 9-3 that total aerospace revenue was
$103.6 billion in 1987, the various product groups having the following
shares:
      SIC 3721 Aircraft - 37.7 percent
      SIC 3724 Aircraft Engines and Engine Parts - 19.6 percent
      SIC 3728 Aircraft Parts and Equipment, NEC - 17.3 percent
      SIC 3761 Guided Missiles and Space Vehicles - 20.8 percent
      SIC 3764 Space Propulsion Units and Parts - 3.4 percent
      SIC 3769 Space Vehicle Equipment, NEC -'1,1 percent
                                  9-13

-------
      Military production has historically been more significant than
commercial production, accounting for an average of 60.6 percent of the
output of the aerospace industry over the period 1986 to 1990.4  With
the U.S. Federal Government as the main customer in the military segment
of the aerospace market, purchasing a typical 92.3 percent of the
military output of the industry in 1990,5 the health of the aerospace
industry is very sensitive to changes in the Federal defense budget.
      Table 9-4 indicates that real Federal spending on aerospace
products and services began to decline in 1988.  The increase in NASA's
spending over the period 1978 to 1990 suggests that the military sector
of the aerospace industry could look to the production of space vehicles
as a potential source of growth, thereby attenuating the decline in the
Department of Defense (DOD) budget.
      In the commercial segment of the market, 9.2 percent of non-
military output was purchased by the U.S. Federal Government while 90.8
percent was purchased by other customers such as airlines and
businesses, both foreign and domestic.6
      At the end-product stage (SICs 3721 and 3761), both the commercial
and the military segments of the market are characterized by highly
differentiated products each of which can be regarded as unique.
Because other products in the "product group" are close substitutes,
however, producers enjoy only limited monopoly power in these markets.
Limited though the monopoly power may be, it allows each firm to behave
as if other firms will not react to changes in its pricing (or other)
behavior.  This, together with the fact that any producer may affect
                                  9-14

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price — there being few producers — is sufficient to render price
indeterminate in the market.  Such is the consequence of oligopoly, the
market structure characterized by few producers selling differentiated,
though not distinct, products.
      On the demand side, the commercial and military segments are
significantly different.  There are many customers in the commercial
segment, including airlines and businesses, while there is for all
practical purposes only one customer in the military segment, namely the
Federal Government.  One buyer or monopsony in the military segment
suggests greater bargaining power, making it easier for the Federal
Government to get favorable terms.  During the 1980s, for example, the
DOD had a marked preference for fixed price contracts with the
consequence that military aircraft producers had to bear all cost
increases,, some suffering substantial losses.
      The markets for other products (i.e., those in SICs 3724, 3728,
3764, 3769, 3599) are rather more difficult to characterize.  At each
stage there are many sellers and buyers, the latter being the producers
of complete aircraft, guided missiles, and space vehicles (SICs 3721 and
3761).  Producers in SICs 3721 and 3761 award contracts to parts
producers in SICs 3728 and 3769 as well as to producers in SIC 3599 who
perform tasks such as coating and machining, all of which are inputs in
the production of complete units.  Commercial airlines and the DOD
purchase engines and propulsion units from producers in SICs 3724 and
3764.
      9.1.3.2  Production.  Table 9-5 presents data on the physical
output of civilian and military aircraft.  Though not shown in the
                                  9-16

-------
                            TABLE  9-5

          SHIPMENTS OF  COMPLETE  U.S. AIRCRAFT  1978-1992
                   (VALUES IN 106 1987  DOLLARS)
Year
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
Total Aircraft
Units
19 ",958
19,297
14,681
11,978
6,244
4,409
3,935
3,610
3,258
3,010
3,254
3,675
3,418
3,244
3,132
Value
10,177
15,074
18,950
20,093
19,257
22,519
21,933
28,386
34,809
35,925
34,875
34,229
41,920
44,273
43,989
Civilian Aircraft
Units
18,962
18,460
13,634
10,916
5,085
3,356
2,999
2,691
2,151
1,800
1,949
2,448
2,268
2,239
2,262
Value
6,458
10,644
13,058
13,223
8,610
9,773
7,717
10,385
11,857
12,148
15,858
17,129
24,476
28,226
28,928
Military Aircraft
Units
996
837
1,047
1,062
1,159
1,053
936
919
1,107
1,210
1,305
1,227
1,150
1,005
870
Value
3,719
4,430
5,892
6,870
10,647
12,746
14,216
18,001
22,952
23,777
19,020
17,100
17,444
16,047
15,063
Source: U.S. Dept. of Commerce, International Trade Administration,
        U.S. Industrial Outlook. 1992, Table 3, p. 21-6.
                                  9-17

-------
table, the number of units of general  aviation aircraft and rotorcraft
fell dramatically over the period 1978 to 1991 while the overall  number
of units of large transport aircraft increased over the same period.
There was no obvious trend in the number of units of military aircraft
produced.  Since the size and performance of aircraft change with
changes in specifications, very little can be concluded from these data
about the state of the industry.  The data do show that the industry is
quite dynamic, with new products being constantly developed to increase
technical efficiency and to meet changes in demand.7
      The discussion of production will henceforth focus on the value of
production because the heterogeneity of the output of the aerospace
industry makes it difficult to analyze physical output.  Annual
production shall be taken to be the value of shipments or sales,
measured in constant (1987) dollars.
      Table 9-6 presents data on new orders, shipments, backlog,  and
inventories for the entire aerospace industry. (Depending on the
product, the length of lag between the placement of orders and the
production of complete units can range from 1 to 5 years.)  After
reaching an all time high of $151.8 billion in 1989, net new orders fell
to $130.6 billion in 1990.  This dramatic fall in net new orders led to
a decrease in the rate of growth of the industry's backlog of orders,
given a fairly constant rate of growth of shipments.  When current
dollars are used, the following identity holds by definition:
      Backlogt - Backlog^, = Net New Orderst - Net  Salest
The subscripts indicate different time periods.  Industry backlog, that
stood at $216.6 billion in 1990, continues to grow, suggesting that
                                  9-18

-------
                               TABLE 9-6

        ORDERS,  SHIPMENTS,  BACKLOG,  AND INVENTORIES OF AIRCRAFT,
           MISSILES, SPACE VEHICLES, AND PARTS, 1978 TO 1990a
Year
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
New Orders
(106 1987
Dollars)
93,095
104,593
100,686
78,355
81,798
92,423
89,929
100,889
107,509
114,835
134,610
151,785
130,678
Shipments
(10* 1987
Dollars)
63,855
74,459
81,204
79,967
74,061
79,684
77,675
91,337
101,376
103,590
105,945
106,239
114,517
Backlog
(106 1987
Dollars)
93,761
114,944
122,967
107,615
105,022
112,860
116,474
128,216
133,775
145,622
171,853
208,491
216,598
Inventories
(106 1987
Dollars)
19,090
22,013
27,359
29,243
31,333
31,504
32,446
36,588
38,277
39,155
42,945
47,760
50,562
8 Deflated by the "Composite Price Deflator for the Aerospace Industry,'
  Aerospace Industries Association, Aerospace Facts and Figures 1991-
  1992.

Source:  U.S. Dept. of Commerce,  Bureau of the Census, "Manufacturers
         Shipments, Inventories,  and Orders" Series M3-1 (Monthly).
                                  9-19

-------
production levels can be maintained at least in the short run though the
demand for aerospace products is declining.
      Since the industry produces to order,  it does not keep inventories
of complete aircraft, spacecraft, aircraft engines, or spacecraft
propulsion units.  Inventories may be interpreted as work, performed
under a fixed price contract, that is yet "in progress."8  (Work done
on a cost plus contract is reported as a shipment and reflects the cost
incurred plus a portion of the profits for the contract during the
year.)
      Figure 9-2 suggests a rough correlation between total aerospace
production and real gross domestic product (GDP).  Given the cost of
aerospace products and the uncertainty about future real GDP, it is not
surprising that the rate of increase in production exhibited more
variation than did the rate of growth of real GDP.
      Table 9-7, which gives production as the value of shipments in
1987 constant dollars, shows that aircraft production contributed an
average of 37 percent of total aerospace output, ranging from 35.6
percent in 1984 to 37.4 percent in 1992, as calculated from Table 9-6.
In 1990, the combined production of aircraft, engines, and parts set a
record high.
      In Figure 9-3, the annual percentage change in real shipments
(i.e., production), measured in 1987 dollars, is presented for each SIC
code.  Particularly noticeable is that, while total shipments of
aircraft grew over the period 1984 to 1990 as shown in Table 9-6, the
rate of growth of aircraft production declined almost consistently since
1985, even becoming negative in 1989.  Though the growth rate of
                                  9-20

-------
   Figure 9-2. The Relationship Between RGOP and Aerospace Production
a
0
01
                      -i	1	1	1	1	1	1	1	1	1	r
             1978   !   1980   !  1982  |   1984  |   1986  |   1988   I   1990  |
                 1979     1981      1983     1985      1987     1989     1991



                                   D   Real GDP
  0
  a
 a
 O\
         1.2
         1.1 -
               1978 1979  1980  1981 1982  1983  1984 1985  1986  '987 1988  '989  1990
                               O  Aerospace Shiomenfs



                                          9-21

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production picked up in 1990,  it is expected that this industry will
experience negative growth rates in production in the ensuing years.
      Capacity utilization rates are summarized in Table 9-8.  In 1990,
capacity utilization fell  in all SIC codes except SIC 3724 and SIC 3769.
The entire aerospace industry utilized an average of 70.8 percent of
full capacity in 1990 with the aircraft industry using only 63 percent,
a dramatic decline from the 80 percent capacity utilization rate of
1989.  This decline may be partially accounted for by recessionary
factors.
      In conclusion, 1990 was an important year for the aircraft
industry, both because it saw the industry outperforming any other in
the aerospace industry and particularly because 1990 marked a watershed
in the demand for military aircraft.
      9.1.3.3  Employment.  There are various measures of employment in
the aerospace industry.  Total employment includes administrative
workers as well as production workers.  A more accurate representation
of employment is given by the number of labor hours devoted to
administration and production but an analysis of the data showed a close
relationship between the number of labor hours and the number of
production workers.  Table 9-9 presents data on the number of production
workers in each SIC code for the period 1987 to 1992.
      Figure 9-4 shows production workers employed in each SIC code as a
percent of all the production workers in the aerospace industry.  Over
the period 1978 to 1992, SIC 372, Aircraft, Engines, and Parts employed
approximately 80 percent of all the production workers in the industry.
                                  9-24

-------
                               TABLE 9-8

               CAPACITY UTILIZATION RATES,  U.S.  AEROSPACE
                          INDUSTRY, 1989,  1990
SIC
3721
3724
3728
3761
3764
3769
Industry
Aircraft
Aircraft Engines and Engine
Parts
Aircraft Parts and Equipment,
NEC
Guided Missiles and Space
Vehicles
Space Propulsion Units and
Parts
Space Vehicle Equipment, NEC
1989 (%)
80
78
86
71
74
57
1990 (%)
63
80
82
70
71
59
Source: U.S. Dept. of Commerce,  Bureau of the Census Current Industrial
        Reports. "Survey of Plant Capacity,  1990," Table 1,  p.  9.
                                  9-25

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Production workers contributed 73.8 percent of the value added reported
by facilities in SIC 372 and 53.8 percent of the value added reported by
facilities in SIC 376, implying that labor is relatively more important
in aircraft production compared with the production of guided missiles
and space vehicles.
      Figure 9-59 indicates  that,  over the period 1978 to  1987,
production workers contributed more (as measured by their wages) to the
value added of parts production than to the value added of either final
assembly or engine/propulsion manufacture in both SIC 372 and SIC 376.
This implies that SICs 3738 and 3769 are relatively labor intensive.
      9.1.3.4  Demand/Consumption.  In Section 9.1.3.2, production was
taken to be shipments, measured in constant dollars.  In the absence of
inventories, annual consumption can likewise be taken to be annual
shipments.  Demand, the amount that domestic and foreign customers are
willing and able to purchase at a given price, over a given period of
time, is better given by net new orders that is the sum of shipments
plus the change in the backlog of orders created by new orders and the
cancellation of old orders.10
      The demand for military aircraft derives, as noted earlier, from
the demand for national defense, while the demand for commercial
aircraft derives mainly from the demand for air travel, both business
and leisure.  While the commercial sector is increasing its use of space
vehicles as technological advances enhance the applicability of these
products and makes them more commercially viable, it can be reasonably
though not accurately assumed that most of the demand for space vehicles
derives from the demand for national security, a significant part of
                                  9-28

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which is national defense.  Naturally, the demand for missiles
originates in the military sector.
      In 1987, the military sector consumed approximately 60 percent of
the output of the aircraft industry as measured by the value of
shipments and 67 percent as measured by the number of units shipped.
This reflected the significant shift in demand, over the period 1986 to
1990, from the military sector to the commercial sector.  Net new orders
increased from $110.3 billion (1987 dollars) in 1986 to $132.1 billion
in 1990.  This 19.8 percent increase in demand was made up of a 26.9
percent fall in demand in the military sector and a 100.2 percent
increase in demand in the commercial sector.11'12
      Apparent consumption in the aerospace industry is given by the
following:
      Consumption = Value of product shipments - Exports + Imports.
      Table 9-10 reports apparent consumption data for the years 1987 to
       *
1990.  As can be seen, the U.S. imports only about 10 percent of the
aircraft it uses while imports of missiles and spacecraft are
negligible.  Such a conclusion is easily challenged if it can be shown
that, even though imports of complete aircraft, missiles, and space
vehicles are insignificant, imports of components are significant.
      Table 9-11 presents data on the value added by imports of engines
and parts to aircraft and the value added by propulsion units and parts
to guided missiles and space vehicles.  It is apparent that imports
constitute a relatively insignificant part of the complete units at SIC
3761, Guided Missiles and Space Vehicles.  This is not surprising since
very few military products are imported, given the need for a high level
                                  9-30

-------
                                     TABLE 9-10

                    APPARENT CONSUMPTION OF AEROSPACE PRODUCTS,
                            1987-1990 (106 1987 DOLLARS)
SIC
3721

3761

Item
Aircraft
(% Imported}8
Guided Missiles
& Space
Vehicles
(% Imported)8
1987
27,082.06
(8.1)
15,706.8
(0.3)
1988
27,550.6b
(9.7)
14,999.9
(2.5)
1989
26,102
(10.0)
15,532.3
(0.04)
1990
26,144.1
(9.7)
14,558.8
(0.03)
8 Import data are deflated by the "Composite Price Deflator for the Aerospace
  Industry," Aerospace Industries Association, Aerospace Facts and Figures, and
  expressed as a percent of "Apparent Consumption."

b Trade data are taken from the 1990 U.S.  Industrial  Outlook.

Source:  U.S. Department of Commerce, U.S. Industrial Outlook. 1992, 1990.
                                        9-31

-------
                                     TABLE 9-11

               PERCENT VALUE ADDED BY  IMPORTS TO INTERMEDIATE  PRODUCTS
                AND COMPLETE UNITS OF THE U.S. AEROSPACE  INDUSTRY,
                                     1989-1991
Code
3724
3728
Industry
Aircraft Engines and
Engine Parts
Aircraft Parts and
Equipment, NEC
% Value Added to Complete Aircraft by
Imports of Engines and Parts
37&1
3769
Space Propulsion Units
and Parts
Space Vehicle Equipment,
NEC
% Value Added to Complete Missiles and
Space Vehicles by Imports of Propulsion
Units and Parts
1989
10.1
^4
17.5
0.02
0,6
0.62
1990
10.6
J-J.
18.3
0.03
0.47
0.5
1991
11.0
_8,5
19.5
0.06
0.48

0.54
Source:  Calculated from the U.S. Dept. of Commerce,  U.S.  Industrial Outlook. 1992,
                                        9-32

-------
of security in military production.  (It is being assumed that most of
the output classified under SIC 376 is produced for military purposes.)
      In contrast, an average of 18.4 percent of the value of complete
aircraft consisted of imported engines and parts.  It is not implausible
therefore, to envisage domestic producers purchasing more imported
engines and parts after an increase in the cost of producing
technologically comparable aerospace equipment.
      9.1.3.5  Profitability.  Compared with other manufacturing
companies, the aerospace industry is characterized by relatively narrow
profit margins (return on sales) and erratic profit fluctuations.13
Table 9-12 shows that, for the past three decades, profit margins have
been consistently below the average for all manufacturing companies.
      In 1991, net profit margins fell to 3.3 percent, down from 3.4
percent in 1990.  It is apparent from the table that the return on
                                                                  •
assets is also less than the average for manufacturing companies.  The
noteworthy difference is that the return on equity has generally been
higher than the average for manufacturing companies.
      In accounting for the relatively low net return on sales and
assets as against the relatively high return on equity, it will be
recalled that the aerospace industry has experienced low capacity
utilization rates.  Furthermore, in the realm of producing on an order
basis, there is little scope for increasing sales through advertisement.
The profitability of the industry is therefore quite sensitive to the
profitability of customers' orders as well as budget decisions of the
Office of Management and Budget.
                                  9-33

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      Firms in the aerospace industry are now responding to the decline
in profit rates and profit levels by diversifying.  This is to be
expected in an industry that employs highly skilled workers.
      9.1.3.6  Foreign Trade and International Competitiveness.  This
section also focuses on the OEM segment of the market.  The trade
balance, calculated from Tables 9-13a and 9-13b, increased from $16.5 to
$41.7 billion (1987 dollars) over the period 1988 to 1991.  Moreover,
1990 was the sixth consecutive year of rising trade surpluses.
Aerospace exports amounted to 9.9 percent of all U.S. merchandise
exports in 1990, thereby offsetting trade deficits in other sectors of
the economy and confirming the importance of the industry to the health
of the economy.
      An analysis of Table 9-13a reveals that aircraft exports
constituted approximately 51 percent of all aerospace exports over the
period 1988 to 1991, growing annually at an average rate of 17.5
percent.  Not surprisingly, exports of civilian aircraft dominated
exports of military aircraft.
      While imports are relatively insignificant, it is apparent that
the volume of imports has been growing at an increasing rate, especially
in the products categorized in SIC 3724, Aircraft Engines and Engine
Parts and SIC 3728, Aircraft Parts and Equipment, NEC.  Imports of
aircraft engines and parts constituted an average of 70.7 percent of
total imports for the period 1988 to 1991 (calculated from Table 9-13b).
It will be recalled from the discussion of domestic consumption that
imports of complete aircraft, including the value added by imported
parts was approximately 9.9 percent of total consumption for the period
                                  9-35

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1987 to 1991.  Imports of complete spacecraft and missiles constituted
about 0.14 percent of total  consumption for the same period.
      Civilian products accounted for more than 80 percent of the total
U.S. aerospace exports in 1990,  increasing from $25.6 billion in 1989 to
$31.5 billion in 1990.  Commercial transport aircraft constituted about
half of civilian exports.
      Associated with the improving balance of trade position for the
U.S. aerospace industry is a decline in the share of U.S. exports of
aerospace products in the world market from about 80 percent in 1970 to
60 percent in 1990.14
      Europe has provided the most formidable competition to the U.S.
aerospace industry.  The U.S. Industrial Outlook points out that the
european aerospace industry grew twice as fast as its counterpart in the
U.S. during the period 1978 to 1989.15   This  historical trend has  been
exacerbated by the creation of the Airbus Industrie consortium by
France, Germany, Spain, and the U.K.  Other countries seeking bigger
shares in the global industry are Canada, Brazil, South Korea,  China,
Taiwan, Singapore, Sweden, Israel, and Australia.16
9.1.4  Outlook
      In the short term, the growth in aerospace sales will continue to
be slow.  During 1990, aerospace manufacturers added 17 percent fewer
new orders to their books than were added during 1989.1/   The U.S.
Industrial Outlook points out that this decline in orders will  be
particularly severe in the military segment where 1990 orders fell by 29
percent over 1989.  It will be recalled from Table 9-6, however, that
the entire aerospace industry had a backlog of orders of $216.6 billion
(1987 dollars) in  139G so that production car, continue for a limited
                                  9-38

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time.  There are indications that this backlog has begun to shrink,18
implying that production rates will have to decline.  In the short run
therefore, employment is expected to fall for each SIC code.
      In the long term, the industry will begin to respond to demand
shifts and cost changes.  The commercial space business is expected to
grow more than any other aspect of the industry.  A recent example20 of
the growth in commercial space business is the worldwide mobile
telephone system proposed by Motorola.  The company will employ 66
satellites in 10 "necklaces" around the globe.  Similar systems but with
fewer satellites are operated by Loral (Globalstar) and TRW (Odyssey).
      The role of technology cannot be overstated.  New, high
performance materials requiring less rework will be used in the
industry.
      There will be increased competition from abroad, leading to
declines in the U.S. share of the world market.  Firms will respond by
restructuring and diversifying.
9.1.5  Rework in the Aerospace Industry
      9.1.5.1  Overview.  Original equipment can be classified into two
categories:  equipment such as missiles which once used cannot be
retrieved, and equipment such as aircraft which have a longer useful
life and therefore require repair and maintenance over the life cycle.
      Rework may be understood to range from minor, routine maintenance
to major overhaul, the degree of rework and the amount of coatings and
solvents used being generally correlated.  In the case of commercial
passenger aircraft for example, routine "line maintenance" that takes
place between flights requires small amounts of coatings and solvents
compared with major overhaul on airframes.  For the purposes of this
                                  9-39

-------
profile, rework shall be taken to mean repair and maintenance that is
undertaken to preserve and extend the useful life of the aerospace
equipment rather than the continual  repair and maintenance necessary for
the regular operation of the equipment.  This latter shall be referred
to as routine repair and maintenance (R&M).
      On the basis of the type of aerospace equipment on which rework is
being performed, there can be said to be four categories of rework:
      •     Rework on large commercial transport aircraft.
      •     Rework on general aviation aircraft.
      •     Rework on military aircraft.
      •     Rework on military/government space vehicles and guided
            missiles.
      There is no separate classification in the SIC system for any form
of rework.  Rework on aircraft, when done by OEMs (i.e., "factory
rework"), is classified under SIC 3721, Aircraft, while non-factory
rework is classified under SIC 4581, Airports, Flying Fields, and
Aircraft Terminal Services.  Furthermore, rework on guided missiles and
space vehicles, if this does occur,  is not recognized.  All civilian
aircraft repair stations must comply with Federal Aviation Regulation
(FAR) Part 145.  According to the FAA Advisory Circular No. 140-7F,
there are 4,300 such repair stations engaged in the repair of airframes,
power plants, propellers, radios, instruments, and accessories.21
      In the case of commercial aircraft, the majority of rework is done
on a non-factory basis, either by the air carriers or in independent
repair stations engaged in "third party maintenance."
      9.1.5.2  Large Commercial Transport Aircraft
      9.1.5.2.1  The Demand Side.  Much of the information on rework of
large commercial transport aircraft is drawn from a General Accounting
                                                                  •
Office  (GAO) survey conducted in 1991.22  Large  commercial  aircraft are
                                  9-40

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defined as passenger or cargo aircraft that "carry more than 30
passengers or a payload greater than 7,500 pounds."23   Such  aircraft
are covered by regulations in Part 121 of the FAR.
      The demand for rework, an input used in the production of the
final goods for air travel/transport, is affected by a number of factors
other than the cost of rework or the price of the final goods.  These
include:  (a) the FAA's aging aircraft airworthiness directives (ADs),
(b) the age of aircraft, and (c) the demand for air carrier services:
      (a)   The FAA's airworthiness directives became more stringent
            after an accident on April 28, 1988, in which 18 feet of
            skin ripped from the fuselage of a 19-year old Aloha
            Airlines Boeing 737 while the aircraft was in flight.24
            Figure 9-6 shows that aging aircraft ADs have the greatest
            impact on the demand for heavy airframe maintenance.  The
            diagram also shows the impact of other factors on the demand
            for rework.  Apart from the label "service bulletins," the
            diagram is fairly self-explanatory.  Aircraft manufacturers
            issue regular service bulletins suggesting improvements and
            modifications that may be undertaken by aircraft owners.
            Airlines also try to standardize the equipment in their
            fleet.
      (b)   In 1991, about 1,400 or 34.1 percent of the 4,100 large
            transports in the U.S. required major overhaul.  The oldest
            aircraft were the Boeing 727s, 737s, 747s, and the Douglas
            DC-8s, -9s, -10s, and MD-80s.25   Figure 9-7 shows  the  age
            profile of the March 1990 fleet of aircraft as it will be in
            the year 2000. It assumes that none of the aircraft will  ba
                                  9-41

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 Figure 9-6.  Relative impact of Several Factors on Heavy Airframe Maintenance In 1990
  Maintenance Demand for 1990
  35
        FAA AD's
 Unforseen
Maintenance
                                       Fleet
                                       Gtowth
Service
Bulletins
Refurbichments  Standardization
     Relative Strength of Responses

     [      { General Impact

             Moderate Impact

         H| Some Impact
         tfm
         •3  No Impact
Source: GAO/RCED-91-91A Aging Aircraft Repairs
                                                 9-42

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Figure 9-7. Age Profile of U.S. Transport Reel In the Year 2000 (as of March 1990)
                                                         V//A  20.3%, Under 5
                                                                16.7%, 5-10
                                                                15.1%, 10-15
                                                                13.3%, 15 - 20
                                                                30.4%, 20-25
                                                                4.2%, 25 and older
Source: GAO/RCED-91-91A Aging Aircraft Repairs. Vol. I. p.13.
                                     9-43

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            retired and excludes  any  purchases  of new  aircraft,  both of
            which would lower the average  age of the fleet.   Given  these
            qualifications,  63 percent  of  the fleet will  be  20 years or
            older in the year 2000.   Measured in years,  the  economic
            design life objective of  these large transport  aircraft is
            20 years.26  Naturally, the demand for rework will be
            greater if air carriers choose to continue using old
            aircraft rather than  to replace them.
      (c)   Greater demand for air carrier services  increases the demand
            for rework through two channels:  the aircraft  fleet may
            increase as new aircraft  are purchased,  and the  existing
            fleet will be used more intensively, to  the extent  possible.
            In 1990, there were 8,302 aircraft  in the  world  fleet,  and
            Boeing predicts that  this number will increase  by 78 percent
            in the year 2005 to 14,772.27  As aging aircraft require
            more rework than new  aircraft, meeting increased demand for
            air carrier services  by the more intensive use  of existing
            aircraft will  lead to a greater increase  in the  demand for
            rework than would the addition of new aircraft  to the fleet.
      Ultimately, the decision to continue using aircraft beyond their
economic design lives is based on cost  considerations, all  factors being
equal.  Overall, costs are usually higher  for old aircraft  than  for new
aircraft, not only because of greater rework costs but also  because of
differences in fuel efficiency and general performance.   Nonetheless,
air carriers may forego purchasing new aircraft if expectations  of
future demand for air services are low or  if interest  rates  are  "too
high."  (Intarast rates ara too high  if the sum of total  interest
                                  9-44

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payments on the new aircraft and the total operating and maintenance
costs exceed the total operating and maintenance costs for the old and
paid off aircraft, for the period beyond the economic design life of the
old aircraft up to the time of its disposal.)  In 1990, for their
domestic operations, U.S. air carriers spent $6,924 x 106 on
maintenance, or 11.7 percent of total operating expenses.  In their
international operations, maintenance expense was $2,050 x 106 or 10.9
percent of total operating expenses.28
      The cost of heavy maintenance varies with the type of aircraft
being serviced as well as the particular work that is to be performed.
The total cost of rework equals the cost of the labor and material
inputs used in the completion of the task, plus the lost income from
having to take the aircraft out of service during maintenance.
Depending on the type of aircraft and the usage, this lost income was
estimated at between $25,000 and $100,000 a day.29   The cost  of rework
on a Boeing 747 was estimated at $2.3 million before the FAA issued its
aging aircraft directives.30  Had  the decision  to perform rework on  an
aircraft been based on a purely economic calculation, the total cost of
rework for the (marginal) oldest aircraft would have equalled the
discounted present value of the stream of income associated with the
extended life given to the aircraft by rework.
      While FAA ADs in particular lead to an increase in the demand for
rework, airlines are undertaking a number of initiatives to reduce their
expenditure on rework.  Moreover, when older aircraft are being
serviced, rework done on them must satisfy regulations that did not
exist at the time of original manufacture.  Thus, new regulations
governing noise, water, and air pollution may, for example, require the
                                  9-45

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replacement of entire engines rather than routine repair and
maintenance.  These considerations can make it more cost effective to
purchase new aircraft, thereby reducing the demand for rework.31  On
balance therefore, it is not clear whether the demand for rework will
increase or decrease in the short-run.
      9.1.5.2.2  Capacity and the Supply Side.  In the GAO survey,  48
out of 54 air carriers responded, representing 99 percent of the large
transport aircraft in the U.S.  Of these, 24 had the capacity to perform
heavy airframe maintenance.  Also surveyed were 38 repair stations, not
related to the air carriers, that had the capacity to perform heavy
airframe maintenance.  Thirty-five (35) of these independent repair
stations responded.32  Therefore,  in  1991,  there were  at  least 64
facilities that had the capacity to do heavy airframe maintenance,  as
determined by hangar space, the availability of spare parts, and skilled
employees.
      Whenever heavy maintenance is being performed, the FAA requires
that the rework facility have the hangar space to fully enclose large
transport aircraft.33  This  technical  requirement  has  the economic
consequence of precluding contract work to smaller repair stations and
any kind of specialization that may follow.  In this regard, rework
facilities contrast to OEM facilities that are quite specialized (see
Section 9.1.3..1).
      In the past, air carriers with excess capacity in their rework
facilities engaged in third party maintenance for other air carriers,
but this practice ceased as carriers devoted this excess capacity to
their own growing aircraft fleet.34   The  chief source  of  capacity
constraints is hangar space,  increasing the amount of hangar space being
                                  9-46

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both costly and of a long term nature.  The 24 air carriers with rework
facilities now perform only about half of their own maintenance.  As a
result, an increasing number of independently owned rework facilities
has been serving air carriers without their own rework facilities or
whose rework facilities have become inadequate for their needs.  Of the
surveyed facilities, two thirds of the 24 air carriers that do heavy
maintenance expected to be devoting their entire rework capacity to
their own fleet in 1990, whereas only a third of the independent repair
stations expected to be operating above 96 percent of full capacity.35
This being the case, both the air carriers and independent repair
stations plan to increase the hangar space available for rework.
      Another determinant of the capacity of rework facilities is the
size of the pool of available air mechanics.  In their main repair
facilities, the air carriers and independent repair stations reported
that they employed 44,188 air mechanics in 1990.  It is typical for the
size of the facility and its employment of mechanics to be directly
related.  There are small independent repair facilities that employ less
than 100 mechanics and cannot fully enclose one Boeing 737.  One large
national carrier operated a facility "capable of enclosing 20 aircraft
at a time, including 747s, and employing several thousand mechanics."36
      Rework facilities employ a relatively large fraction of the total
number of air mechanics in the country.  In 1988, air carriers amployed
more than 60 percent of the nation's 124,000 air mechanics.37
Independent repair stations, aircraft assembly firms, the Federal
Government, and owners of private aircraft employed the remaining 49,600
air mechanics.  One may therefore argue that rework entails a relatively
                                  9-47

-------
high air mechanic to total  employment ratio and,  therefore,  discuss
employment impacts at rework facilities in terms  of air mechanics.
      The capacity of rework facilities to meet demand is also
influenced by the availability of spare parts.   In order to perform
rework, facilities must be able to purchase required spare parts when
needed.  Repair stations also maintain a stock of spare parts ranging
from engines and airframe components to output classified under SIC
3728, Aircraft Parts and Equipment, NEC.  The inability of OEMs to
provide an adequate supply of spares has been a severe constraint on the
capacity of rework facilities.38   For  facilities that  usually  keep a
stock of spare parts, if there-is urgent need for rework, a shortage of
spare parts at a particular facility may compel air carriers to turn to
repair stations located elsewhere, either within  the country or abroad,
to meet the demand.39
      Regarding foreign repair stations, rework facilities owned by
foreign airlines often have excess capacity that  allows them to service
U.S. aircraft.  Further, there are also foreign repair stations,
independent of the air carriers in those countries, that perform rework
on U.S. aircraft.  These foreign rework facilities may be regarded as
offering competition to domestic facilities.  In  1990, there were at
least 34 foreign independent repair stations with the capacity to
perform heavy maintenance on airframes, ranging from a facility that
could contain one commuter aircraft to one that could enclose six wide-
bodied aircraft.40   These facilities were  scattered  across Europe,
Canada, South East Asia, and Africa.
      In looking abroad for repair and maintenance, airlines are
especially cognizant of tha differences In labor  cost, quite apart from
                                  9-48

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the limited capacity of domestic rework facilities.  Such differences in
labor cost may explain why some European facilities charge three times
as much as their Asian competitors.41
      9.1.5.3  General Aviation Aircraft.  As of June 5, 1992, about
4,236 facilities were certified to perform wide ranging repair and
maintenance on general aviation aircraft.42   These  facilities  engage  in
repair and maintenance of small airframes, powerplants, propellers,
radios, instruments, and accessories.
      Table 9-14 presents employment and revenue information for 138 of
these facilities.  The table shows that for this sample of general
aviation facilities, there are only small and medium facilities.  The
table includes facilities that repair the electronic gadgets on the
aircraft even though such facilities will not be subject to the
regulation.
      9.1.5.4  Military Aircraft. Guided Missiles, and Space Vehicles.
In the following discussion that draws heavily on a 1992 report43  by
the Office of Technology Assessment on the U.S. Defense Technology and
Industrial Base  (DTIB), the last two categories of rework facilities
mentioned in Section 9.1.5.1 will be treated as one.  Chapter 5 of the
report addresses the maintenance base of the DTIB.
      There are essentially three levels of defense maintenance:
organizational,  intermediate, and depot.  Of these, depot level
maintenance, where highly trained personnel rebuild, make complex
repairs on, and overhaul equipment in specialized facilities,44 will  be
likely candidates for the regulation.
      The depot maintenance system is made up a service (i.e., service-
owned and operated) and a private sector component, the former employing
                                  9-49

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                               TABLE 9-14

               FEDERAL AVIATION REGULATION (FAR) PART 145
                 REWORK FACILITIES, NUMBER OF EMPLOYEES
               AND REVENUE BY EMPLOYMENT-SIZE CLASS, 1992
Employment Size
0-9
10-24
25-49
50-99
100-299
300-499
500-999
1,000-3,999
4,000+
Number of
Facilities
43
40
19
16
11
1
3
4
1
Number of
Employees
283
686
704
986
1,842
400
2,297
4,511
4,948
Revenue8
(103)
29,807
48,350
49,000
57,000
145,500
15,000
120,000
1,070,000
N/A
8 Revenue is understated because,  for many facilities,  only
  employment data were available.

Source:  National Aeronautical Repair Station Association.
                                  9-50

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about 150,000 persons, and the latter comprising thousands of firms,
including both rework and OEM facilities.
      In the past, each military service (i.e., the Army, Air Force,
Marine Corps, and Navy) has maintained its own equipment except for a
few select items (e.g., some aircraft engines), for which a single
service has assumed overall maintenance responsibility.45 While these
services use various combinations of air-, land-, and sea-specific
equipment, it is safe to assume that depot maintenance facilities in the
Air Force and, to a lesser degree, the Navy, perform most of the in-
service repair on military aerospace equipment.
      The depot level maintenance of the Air Force is performed in five
major facilities (Air Logistics Centers) and some smaller support
centers.  Very limited depot level rework is performed overseas (see
Table 9-15).  Approximately 60 to 70 percent of the depot maintenance of
the Air Force is performed in the five major facilities, six percent by
other services and the remainder by private firms under  contract.46
      In the fiscal year 1991, total depot level maintenance was about
$4.7 million.  This work was performed by both the service and the
private sector components of the Air Force defense maintenance system.
In fiscal year 1988, the Air Force Logistics Command repaired or
modified 1,307 aircraft, 7,727 engines, and 817,000 exchangeable parts.
In 1992, approximately 90 Air Force systems were being supported
throughout their lives by the private sector.47  Employment  in these
Air Force in-service facilities is expected to decline from 36,000
persons in 1992 to 31,000 in 1995.48
      In the Naval Service, there are six naval aviation depots that,
along with depots in other services and private sector companies,
                                  9-51

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perform depot level maintenance on this service's aerospace equipment.
These Naval aviation depots employed 20,000 persons in 1992.49
9.1.6  Coatings Manufacturing
      Aerospace coatings manufacturing is a subcategory of the more
general classifications of paints and coatings manufacturing and
adhesives and sealants "manufacturing.  These industries fall under SIC
2851, Paints, Varnishes, Lacquers, Enamels, and Allied Products (paints
and coatings), and SIC 2891, Adhesives and Sealants.50 While  control
costs stemming from the aerospace coatings NESHAP will directly impact
aerospace original equipment manufacturers and rework facilities,
coatings manufacturers will be indirectly affected as their products are
inputs into OEM and rework facilities.
      The top ten suppliers of coatings controlled 60 percent of the
U.S. market share in 1990.51   As  of January 1991,  there were 820 firms
in the U.S. manufacturing coatings.
      Table 9-16 presents value of shipments data for the paints and
coatings and adhesives and sealants industries.  Data are presented in
millions of 1987 dollars.  Value of shipments data for paints and
coatings shows a decline from 1988 to 1991.  This is due to the fact
that demand for paints and coatings is closely related to the national
business cycle, and this decline coincides with the downturn experienced
by the national economy.52   End users  of  this  industry include
construction, automotive, aerospace, and electronics, that also tend to
be cyclical in nature.53
      Shipments of adhesives and sealants have similar end uses to
paints and coatings, and also tend to be cyclical in nature.  Sales of
these products were adversely affected by the notable declines  in
                                  9-53

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housing starts in 1991.54  However, this deterioration was  offset  by
significant growth in more specialized end uses such as packaging
adhesives and bonding products for the electronic and wood working
sectors.
      Employment for paints and coatings and adhesives and sealants is
presented in Table 9-17.  As shown, employment for paints and coatings
dropped from 1988 through 1991 due to the above-mentioned downturn in
demand.
      9.1.6.1  Aerospace Coatings.  Aerospace coatings involve the use
of coatings for both OEM and rework facilities.  Within these market
segments, coatings are specialized for use in commercial and military
production.
      No information is available on the share of production that
aerospace coatings accounts for total coatings manufacturing.  However,
a 1990 study covering coatings production in Western Europe revealed
that aircraft OEM coatings accounted for 2.6 percent of that market.
Thus, it is assumed that aerospace coatings account for a relatively
small share of the U.S. coatings market.
      9.1.6.2   Future Prospects for Coatings Manufacturers.  Since both
paints and coatings production and adhesives and sealants production are
cyclical in nature, future growth rates will be linked close to
performance of the national economy.
      Strong growth in demand for paints and coatings are expected for
non-solvent-based materials, including waterborne and higher solids, due
to their lower volatile organic compound (VOC) level.55   Weaker
performance is expected in the architectural coatings sector.16
Overall performance should mirror growth in GNP.

                                  9-55

-------
                                  TABLE 9-17
  EMPLOYMENT FOR PAINTS AND COATINGS AND ADHESIVES AND SEALANTS, 1987 - 1991
                           (THOUSANDS OF EMPLOYEES)
SIC
2851
2891
Industry
Paints and
Coatings
Adhesives
and
Sealants
1987
55.2
20.9
1988
56.9
21.2
1989
55.0
21.9
1990
54.7
22.5
19918
54.5
22.3
8 Estimate

Source: U.S. Department of Commerce, Bureau of the Census,  1987 Census of
        Manufactures. 1987.  Annual Survey of Manufacturers. 1988-1990.
                                     9-56

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      In the adhesive and sealant market, movement is expected away from
solvent-based materials as well, in response to environmental concerns.
Growth in the near term is expected to be 5 percent in real terms.57
Long-term growth should mirror growth in GNP.
9.2  ECONOMIC IMPACT ANALYSIS (EIA)
9.2.1 Introduction
      Compliance with the proposed NESHAP will result in total annual
costs of approximately $21 million to the aerospace industry.58   As
will be explained further in this section, this cost is relatively small
compared to total production costs in this industry.  Therefore, the
discussion of the economic impacts will be discussed in a qualitative
manner due to the minimal costs associated with the proposed regulation.
      Section 9.2.2 provides an analytical framework for discussing the
impacts by identifying the aerospace market segments and the final goods
and factor markets that will be affected by the proposed regulation and
by discussing relevant market dynamics.  The implications of having to
comply with the emission standard and the costs and savings associated
with compliance are discussed in Section 9.2.3.  Section 9.2.5 presents
a summary and the conclusion.
9.2.2  Analytical Framework
      This section provides a framework for discussing the impacts
associated with compliance with the regulation.  In this framework,
distinctions are made between primary impacts arising from price and
output changes in the aerospace industry and secondary impacts arising
from changes in the demand for  inputs.
      The aerospace industry engages in both original equipment
manufacture and rework.  Included are those firms producing aircraft,
                                  9-57

-------
(SIC 3721); aircraft engines and engine parts,  (SIC 3724); aircraft
parts and auxiliary equipment,  (SIC 3728);  guided missiles and space
vehicles, (SIC 3761); guided missile,  space vehicle propulsion, and
propulsion unit parts, (SIC 3764);  and guided missile and space vehicle
parts and auxiliary equipment,  (SIC 3769).   These products are produced
and exchanged in the following  markets (hereafter called market
segments):
         Commercial OEMs, SICs  3721, 3724,  3728
         Military OEMs , SICs 3721, 3724,  3728, 3761, 3764, 3769
         Commercial Rework
         Military Rework.
One commercial rework facility categorized its operations as Airports,
Flying Fields, and Services, SIC 4581.59
      When broken down by size, it is possible to distinguish which
facilities in these market segments perform similar activities among
those that are considered to be emission sources under the potential
NESHAP.  This classification of facilities defines "model plants," the
basis of the definition being the number of employees - small, medium,
and large facilities having respectively 999 or fewer; 1,000 to 9,999;
and 10,000 or more employees.
      The producers of aerospace products purchase a variety of inputs
or factors of production from "upstream" suppliers.  The input markets
that will be affected by the proposed NESHAP are the markets for
aerospace coatings and solvents, pollution control equipment, and labor.
Aerospace products are purchased by civilians, businesses, air carriers,
and the government in response to the demand by air travellers and
taxpayers for air travel, cargo transportation, space exploration, ana
national security.
                                  9-58

-------
      Figure 9-8 summarizes how the regulation of activities in the
aerospace industry will affect producers in this industry as well as
producers in related industries through the indicated demand and supply
channels.  The diagram also shows the relationship between the users of
aerospace products and the aerospace industry and factor markets.  The
market dynamics that lead to these effects will be discussed as primary
and secondary impacts, respectively.
      9.2.2.1  Primary Impacts.  Cost estimates indicate that the
requirements associated with the proposed regulation will cause
industry-wide production costs to increase by approximately $21 million
(1990 dollars) annually.60   This  cost  includes  the  cost  associated with
additional control or substitution requirements as well  as monitoring,
recordkeeping, and reporting requirements.  Though total production
costs are unknown, an assumption of zero economic profits in the long
run implies that industry production costs equal industry revenue which,
according to the 1993 U.S.  Industrial Outlook, equalled $118.1 billion
in 1990  (original equipment manufacturing).  Roughly, then, the costs
associated with the standard are only 0.02 percent of total production
costs for the industry.
      Economic profits will be zero if the supply of end products such
as aircraft, guided missiles, and spacecraft to air carriers and the
government is perfectly elastic, a reasonable long run assumption given
that, for travel and cargo, air carriers usually operate in highly
competitive markets.  In the case of government provision of national
security which is a public good, it is assumed that the government is
not a profit (or revenue) maximizer and therefore will pass on all
savings  to the taxpayer.  Figure 9-9 depicts the effect of these savings
                                  9-59

-------
Figure 9-8.  Direction of demand and supply in the Aerospace Industry and of
           impacts of NESHAP proposed for the Aerospace Coatings Industry.
                           Final Consumer
                          (air traveller, taxpayer)

                                      4
                                      i

      Air Transportation, National Security and Space Research
                         (air carriers, government)

                                  4   4
   Point of\
 Regulation /
Aerospace Products (OEM and Rework)
  (SIC's 3721, 3724, 3728, 3761, 3764, 3769)*
                                  •
                                  •
                                  •
                                  T
                       4
                       I
                             Factors/Inputs
              (coatings, solvents, pollution control equipment, labor)
                                                    Key
                                                       Demand
                                             	Suppiy
                                                       Impacts
                                                       Secondary Impacts i
 * These SICs are for original equipment. There is no separate SIC for rework.
                                 9-60

-------
FIGURE 9-9. EFFECTS OF PROPOSED NESHAP ON PRODUCERS OF FINAL
              GOODS IN THE AEROSPACE INDUSTRY*
                     Change in Consumer Surplus
This industry includes goods in SiCs 3721, 3724, 3728, 3761, 3764, 3769.
                              9-61

-------
on air carriers and the government.  The decrease in production costs
causes the supply curve to shift from S0 to  S,.  Unit price  declines
from P0 to Pv  and  output  increases from  Q0 to Qv
      Because the supply curve is assumed to be horizontal,  all the
savings associated with the NESHAP will be passed on to the air carriers
and the government by the aerospace producers.  In turn, it is assumed
that these savings are passed on entirely to the consumer or taxpayer as
indicated by the increase in consumer surplus shown in Figure 9-9.
      Table 9-18 shows the various emission sources, associated with
various activities in the aerospace industry, that are subject to
regulation under the potential NESHAP.  The table also indicates the
cost, for each model plant, of complying with the standard.   The total
costs for small, medium, and large model plants are also presented.
      Although the total cost of the proposed regulation is positive,
some model plants  show negative costs (i.e., savings) and, moreover,
these costs differ across model plant sizes.  While such a pattern of
positive and negative costs for different model plant sizes could, in
theory, cause  shifts in business among model plants of different sizes,
when compared  with total production costs, the absolute numbers are
considered small enough to be inconsequential.
      9.2.2.2  Secondary Impacts.  The expression "secondary impacts"
refers to changes  in factor demand by all aerospace producers
(regardless of where they are in the production process).   For example,
while the primary  impact of the regulation on spray gun cleaning is a
decrease in the cost of performing this  task, the actual cause of the
decrease in cost is a reduction in the use of methyl ethyl  ketone  (MEK)
                                  9-62

-------
                               TABLE 9-18

        PER-PLANT CONTROL COSTS  FOR REGULATED EMISSION  SOURCES8
                         (1990 CONSTANT DOLLARS)
EMISSION SOURCE/
MODEL PLANT SIZE
Aircraft Depainting:
small
medium
large
Chemical Milling
Maskant:
small
medium
large
Spray Gun Cleaning:
small
medium
large
Hand-Wipe Cleaning:
small
medium
large
Primers, Topcoats,
and their
Application:
small
medium
large
Total :
small
medium
large
MARKET SEGMENTS
COMMERCIAL
OEM
N/A
N/A
N/A
N/A
106,680
135,540
(16,720)
(22,100)
(28,000)
7,030
3,510
(9,260)
(36,830)
(67,350)
(520,600)
(46,520)
20,740
(422,320)
MILITARY
OEM
N/A
N/A
N/A
N/A
106,680
135,540
(16,720)
(22,100)
(28,000)
7,030
3,510
(9,260)
(8,680)
(12,450)
(90,830)
(18,370)
75,640
7,450
COMMERCIAL
REWORK
(7,200)
(23,590)
N/A
N/A
N/A
N/A
(16,720)
(22,100)
(28,000)
7,030
3,510
(9,260)
(36,830)
(67,350)
(520,600)
(53,720)
(109,530)
(557,860)
MILITARY
REWORK
(7,200)
(23,590)
(23,590)
N/A
106,680
135,540
(16,720)
(22,100)
(28,000)
7,030
3,510
(9,260)
(8,680)
(12,450)
(90,830)
(25,570)
52,050
(16,140)
a The emission source "Inorganics" is not included because the
  associated costs are not available on a model plant basis.  These
  costs are positive but quite small.

Source:  Facsimile, David Hendricks,  PES,  to Thomas Singh, JACA
         Corporation.
                                  9-63

-------
and other solvents, this reduction in solvent consumption being the
secondary impact.
      Figure 9-10 shows the direction of the change in price and
quantity when the demand for the factor increases (from d to da)  or
decreases (from d to db).   (Unlike in Figure 9-9,  the supply curve is
assumed to be upward sloping in order to demonstrate price and quantity
effects of the changes in factor demand.  Note that in this diagram, it
is the demand curve that shifts along a given supply curve.  In Figure
9-9, it was the supply curve that shifted and the magnitude of the
shift, industry savings, was seen to be small, rendering the assumption
of a perfectly elastic supply curve quite innocuous.  Moreover, that
assumption was defended as realistic.)  When factor demand increases in
response to the emission standard, quantity demanded increases to Qa and
price increases to Pa.  Conversely,  when factor demand decreases in
response to the standard, quantity demanded and price decrease to Qb and
Pb, respectively.  The process "spray gun cleaning" provides an
illustration of how the standard, by requiring the increased use of one
factor (enclosed spray gun cleaners), will lead to a reduction in the
use of another (methyl ethyl ketone).  While these two factors are
produced and exchanged in two distinct markets, the analysis of Figure
9-10 suggests that the equilibrium price and quantity in the enclosed
spray gun cleaner market will increase, and the equilibrium price and
quantity in the methyl ethyl ketone market will decrease.
9.2.3  Discussion of  Economic Impacts
      In discussing the impacts,  it  is necessary to identify those
markets that will be  affected by the potential regulation.  To this end,
the effect of the standard on each emission source will be treated
                                  9-64

-------
 FIGURE 9-10. EFFECTS OF PROPOSED NESHAP ON FACTOR MARKETS*
                              QtPQa
Factors include Aerospace coatings and solvents, pollution control equipment and labor.
                             9-65

-------
separately.  As the primary impacts of the NESHAP are insignificant,
only factor markets (i.e., secondary impacts) will be discussed.
Moreover, while various control options may achieve the standard,  only
the least costly options will be used to calculate economic impacts.
      In this analysis, both negative impacts such as a decrease in
demand for coatings, solvents, or labor, and positive impacts such as an
increase in demand for low-HAP content coatings, will be noted.  When
the potential standard leads to an increase in the demand for pollution
control equipment (e.g., carbon adsorbers), the discussion will
emphasize any associated changes in the demand for coatings and
solvents.
      Regulation of the emission source labelled "aircraft depainting"
will affect primarily rework facilities.  MACT specifies the elimination
of organic HAP-containing chemical strippers (except for a 20 gallon per
aircraft allowance for spot stripping and decal removal).  Compliance
can be achieved through the use of non-HAP chemical strippers or media
blasting techniques such as wheat starch or plastic pellet blasting.
      The least costly control option for aircraft depainting is the use
of chemical strippers that contain no organic HAPs.  No additional
equipment is required under MACT and the number of hours required to
perform the task of depainting is unchanged.  Table 9-19 shows that the
regulation will lead to a 1.6 million gallon decline in the annual
consumption of methylene chloride-based chemical strippers and a 1.8
million gallon increase in the annual consumption of chemical strippers
that contain no HAPs.
      For the emission source 'chemical milling maskant," performed in
commercial/OEM, military/OEM, and military rework medium and large
                                  9-66

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facilities, maskant consumption varies only with the size of facilities.
Moreover, the least costly control  technique is not identical  across
facility sizes.
      As one control option, carbon adsorbers can be used with the
baseline solvent-based maskants.  Operation of carbon adsorbers requires
more labor and utilities and also requires replacement carbon.  (It is
not possible to calculate this change in labor requirement from the
available information.)  The other control option specifies the
substitution of waterborne maskant for the baseline solvent-based
maskants.  Use of waterborne maskants requires stainless steel tanks to
replace the tanks used for solvent-based maskants.  Additionally,
waterborne maskants require ovens for drying.  Waterborne and solvent-
based maskants use the same amounts of labor.
      Compliance will be least costly for the industry if medium
facilities used waterborne rather than solvent-based maskants and if
large facilities continued using solvent-based maskants but captured
emissions with carbon adsorbers.
      From Table 9-20, it may be concluded that all the relevant medium
facilities will reduce their annual consumption of solvent-based
maskants by a total of 696,000 gallons, and increase their annual
consumption of waterborne maskants by 620,600 gallons.  The total
consumption of solvent-based maskants in the aerospace industry will
decrease by 67 percent.
      These influences on demand emanating from compliance at this
emission source will place upward pressure on the price of waterborne
maskants and downward pressure on the price of solvent-based maskants.
                                  9-68

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      As large facilities can achieve the required  emission reductions
in the least costly manner by installing carbon  adsorbers,  they will  not
change their annual consumption of solvent-based maskants.
      For "spray gun cleaning," MACT specifies the  substitution of
enclosed spray gun cleaners for "unlimited hand  cleaning".   Impacts
differ only with the size of the model  plants  and not by work type
(commercial/military, OEM/rework).  The use of enclosed spray gun
cleaners will lead to a decrease in solvent consumption, typically MEK.
The labor requirement for spray gun cleaning is  unaffected by the
standard.
      It can be concluded from Table 9-21 that the  average annual
consumption of solvents in the aerospace industry will decrease from
14,405,100 to 3,799,640 gallons, or 74 percent,  as  a direct consequence
of the use of enclosed spray gun cleaners.
                                                                 •
      "Hand-wipe cleaning" is performed in all facilities and solvent
consumption varies only with the size of facilities, not with the work
type.  MACT for hand-wipe cleaning specifies product substitution and
the implementation of a housekeeping system.  Product substitution
refers particularly to the substitution of aqueous  and low vapor
pressure cleaners for MEK which is typically used in the baseline.
      The housekeeping system under MACT involves the use of
(a) scalable fiber drums and aluminized bags to  capture fugitive
emissions from solvent-laden rags and (b) compactors for compressing
solid waste.  This housekeeping system will lead to a reduction in the
required amount of solvent.  Thus, as may be seen from Table 9-22,
instead of using 46,575,900 gallons of MEK each  year for hand-wipe
                                  9-70

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                                                          9-72

-------
cleaning, the aerospace industry will use 14,904,288 gallons of solvents
with a lower vapor pressure.
      While there may be a change in the labor requirement associated
with the disposal of solvent-laden rags, it is only possible to say that
this change should be proportional to the change in the actual number of
solvent-laden rags which in turn should be proportional to the change in
solvent consumption.
      For "primers, topcoats, and application methods," MACT specifies
(a) the substitution of low-HAP content primers and topcoats (coatings)
for high-HAP content coatings and (b) the use of high transfer
efficiency methods (namely high volume low pressure (HVLP) spray guns)
for primer and topcoat application.  The use of HVLP spray guns reduces
the annual average consumption of coatings, and this in turn reduces the
number of labor hours spent on the corresponding coating operations.
      For both coatings substitutions and high transfer efficiency
methods, the impacts differ in commercial and military facilities but
are independent of whether the work being performed is original
equipment manufacture or rework.  For both MACT specifications, impacts
vary with the size of the facility.
      Tables 9-23a and 9-23b show the annual consumption of primers and
topcoats in the baseline and after the regulation.  Primer consumption
will decline by 24 percent, from a baseline volume of 2,529,760 gallons
per year to 1,927,600 gallons per year under MACT.  Similarly, topcoat
consumption will decline by 25 percent, from an annual baseline
consumption of 2,132,100 gallons to 1,601,960 gallons,  In both
instances, the reduction in volume is the result of greater efficiency
in application methods.
                                  9-73

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      As the amount of primers and topcoats will decrease following the
regulation, so will the labor hours required to apply these coatings.
The industry's annual labor requirement associated with this emission
source will fall by approximately 1,771,160 hours or 852 persons per
year, assuming 2080 hours per person-year.61
      The final emission source is "inorganics," for which the
incremental cost of compliance is the cost of implementing MACT.62
MACT specifies the construction of booths or hangars in facilities that
currently do not paint within such enclosures and the installation of
dry filters or waterwash in all booths or hangars.  As such, while there
will be an increase in the demand for pollution control equipment, there
is no product substitution nor is there a change in the consumption of
coatings, solvents, or labor.
9.2.4  Small Business Impacts
      The purpose of this section is to address the possibility that the
proposed rule will significantly impact small entities in the aerospace
industry.  The Small Business Administration defines any establishment
within SIC 3724, 3728, 3761, 3764, and 3769 as a small entity if it
employs 1,000 employees or less.  Establishments within SIC 3721 must
employ less than 1,500 employees to qualify as a small entity.  Although
the possibility of the proposed rule affecting establishments classified
as small entities exists, the EPA does not anticipate that the proposed
rule will have a significant impact on a substantial number of small
entities.
      As discussed in Section 9.1.2,. the manufacturing and assembling of
complete products in the aerospace industry take place in a complex
manner.  This process involves prime contractors as wall as ssvaral
                                  9-76

-------
tiers of subcontractors.  One SIC code may consist of a number of
establishments of vastly varying sizes engaging in a number of different
activities, with the small establishments engaging in activities that
contribute the least value-added to the final product.
      For example, SIC 3721 consists of establishments of different
sizes that manufacture or assemble complete aircraft; modify,  convert,
or overhaul previously accepted aircraft; engage in research and
development; and provide aeronautic services on complete aircraft.   Each
establishment contributes a different amount of value-added to the  final
product, with activities generating the least value-added typically
employing less than 1,000 production workers.  This situation  is also
expected to hold true for the rework segment of the industry.
      The purpose of the proposed rule is to limit HAP emissions from
aerospace facilities that are major sources (as defined in Section
112(a) of the Act) of these emissions.  Establishments most likely  to
qualify as small entities are also least likely to qualify as  major
sources.  As explained above, an establishment contributing a  small
amount of value-added to a final product will not likely generate enough
HAP emissions to qualify as a major source.
      Due to the above reasoning, the EPA has no information indicating
that any small entities would meet the definition of a major source;
therefore, the small entities would not be subject to the proposed  rule
and no impact would occur.  Consequently, a Regulatory Flexibility
Analysis is not required.
9.2.5  Summary and Conclusions
      The primary impacts of this NESHAP occur in the markets  for air
transportation, space exploration, and national security.  There will be
                                  9-77

-------
an industry-wide cost associated with the regulatory requirements, but
the primary impacts will be insignificant on account of the small
magnitude of the costs compared to the industry-wide production costs.
      The secondary impacts of this potential regulation occur in the
factor markets for coatings and solvents, labor, and pollution control
equipment.  Consumption of methylene chloride is estimated to decline by
approximately 1.6 million gallons per year, being replaced by 1.8
million gallons per year of non-HAP strippers.  Consumption of solvent-
based maskants is expected to decline by approximately 700,000 gallons
per year or 67 percent annually, the substitute being waterborne
maskants with a usage of approximately 600,000 gallons per year.  The
aerospace industry's consumption of methyl ethyl ketone is expected to
decline by approximately 57 million gallons per year or 83 percent.  The
consumption of low vapor pressure solvents is expected to increase by
approximately 15 million gallons annually.  Finally, the average amount
of primers and topcoats used annually in the industry will decrease by 6
million gallons or 24 percent and 5 million gallons or 25 percent,
respectively.
      These changes in the demand for coatings and solvents may be
represented by shifts in the respective factor demand curves that will
result in price and quantity changes as illustrated in Figure 9-10.  As
a result, the issue of demand elasticity does not enter and there will
be unambiguous revenue changes associated with the changes in price and
quantity.  Thus, there will be a tendency for the price, quantity, and
revenue to decline in the markets for methylene chloride, solvent-based
maskants, MEK, primers, and topcoats.  Associated with the product
substitution that will take place in tha industry, there will be a
                                  9-78

-------
tendency for price, quantity,  and revenue to increase in the markets for
non-HAP strippers, waterborne maskants, and low vapor pressure solvents.
      Regarding negative impacts, the effects of this NESHAP on
producers of methylene chloride, solvent-based maskants, MEK, primers,
and topcoats will be more severe on the larger producers.  Likewise,
when the NESHAP favors producers of non-HAP strippers, waterborne
maskants, and low vapor pressure solvents, the impacts will be greater
on producers who specialize in a single product.
      It has been established that the use of high transfer efficiency
application methods will lead to annual labor savings equivalent to 852
persons.  The overall change in the demand for labor cannot be
determined from the available information as the labor requirement
increases with the use of carbon adsorbers in chemical milling maskant
and decreases with the housekeeping system recommended for hand-wipe
cleaning.  Without knowing the direction of the change in demand, it
will not be possible to predict the associated changes in price,
quantity, and revenue in the market for labor.
      For the various kinds of pollution control equipment required for
MACT, the increase in demand will, as demonstrated in Figure 9-10,
result in an increase in price, quantity, and revenue.
                                  9-79

-------
      9.3  REFERENCES


1.     Standard Industrial  Classification Manual.  1987,  pp.  12,  13.  Executive
      Office Of The President,  Office Of Management And Budget.

2.     Memorandum. June 30, 1992,  David Hendricks,  Pacific Environmental
      Services, Inc. to Vickie  Boothe, U.S.  EPA:ESD,  "Draft Model  Plants for
      the Aerospace NESHAP," Table 3, p. 7.

3.     Census of Manufactures. U.S.Department of Commerce, Bureau of the
      Census, p. 37B-15, Table  5a, "Industry Statistics by Industry and
      Primary Product Class Specialization:   1987."

4.     Current Industrial Reports. U.S. Department of Commerce,  MA37D(90)-1,
      1990, "Aerospace Industries (Orders,  Sales,  Backlog)," Table 3.

5.     Reference 4.

6.     Current Industrial Reports. U.S. Department of Commerce,  MA37D (90)-1,
      1990, "Aerospace Industries (Orders,  Sales,  Backlog)," Table 4.

7.     "A Survey of The Civil Aerospace Industry:  All  Shapes and Sizes," The
      Economist. September 3, 1988.

8.     Reference 4, p.5.

9.     Census of Manufactures. U.S. Department of Commerce, 1987, Table la, pp.
      37b-6,7.

10.   Reference 4, p.5.

11.   Reference 4, Table 3.

12.   "Composite Price Deflator  for the Aerospace Industry," Aerospace Facts
      and Figures. 1991-1992. Aerospace Industries Association.

13.   Industry Surveys. Standard and Poor,  June 25, 1992, p. A31.

14.   U.S. Industrial Outlook.  U.S. Department of Commerce, International
      Trade Association, 1992,  p. 21-2.

15.   Reference 6, p. 21-2.

16.   Reference 6, p. 21-3.

17.   Reference 6, p. 21-4.

18.   "Why Boeing Doesn't Have The All Clear Yet," Business Week.  May 11.
      1992, pp.78-79.

19.   Reference 14.

20.   The Economist, Aug. 29-Sept. 4 1992,  p.74.

                                        9-80

-------
21.   "FAA Certificated Maintenance Agencies Directory," Advisory Circular,
      No. 140-7F, U.S. Department of Transportation,  Federal Aviation
      Administration, August 1992.
22.   Aircraft Maintenance: Additional FAA Oversight Needed of Aging Aircraft
      Repairs. U.S. General Accounting Office, May 1991, Vol. I, II [GAO/RCED-
      91-91A].
23.   Reference 22, Vol.1, p. 11.
24.   Reference 22, Vol.1, p. 14.
25.   Reference 22, Vol.1, p. 2.
26.   "Old Planes, New Money," Air Transport World. 1/89, p. 53.
27.   Reference 22, Vol.1, p. 22.
28.   Reference 9.
29.   Reference 22, Vol I, p. 26.
30.   Reference 22, Vol.1, p. 21.
31.   "Environmental Rules Create Maintenance Needs and Problems," Aviation
      Week and Space Technology. February 8, 1988.
32.   Reference 22, Vol.  I, p. 17.
33.   Reference 22, Vol.  I, p. 45.
34.   Reference 26, p. 42, January 10-16, 1990.
35.   Reference 22, Vol.  I, pp. 47-48.
36.   Reference 22, Vol.  I, p. 32.
37.   Reference 22, Vol.  I, p. 41.
38.   "Shortage of Replacement Parts May Delay Aging Aircraft Repairs",
      Aviation Week and Space Technology. July 2, 1990.
39.   Alternative Logistics Systems For Expensive Parts (An Airline Study),
      William G. Browne,  Bureau of Business Research, Graduate School of
      Business Administration, The University of Michigan, 1969.
40.   "Third Party Maintenance Directory," Flight International. January 10-
      16, 1990.
41.   Reference 40, p. 42.
42.   Memorandum. April 22, 1993 Thomas B. Singh, JACA Corp. to Michele
      McKeever U.S. EPA,  "The Number of General Aviation Rework Facilities and
      the Size Distribution of These Facilities."
                                        9-81

-------
43.   Building Future Security. U.S. Congress,  Office of Technology
      Assessment,  OTA-ISC-530 (Washington,  DC:   U.S. Government Printing
      Office, June 1992).
44.   Reference 43, p. 119.
45.   Reference 43, p. 126.
46.   Reference 43, p. 126.
47.   Reference 43, p. 126.
48.   Reference 43, p. 126.
49.   Reference 43, p. 126.
50.   Standard Industrial Classification Manual. 1987. Executive Office of the
      President, Office of Management and Budget, pp. 142, 148.
51.   "Business Review and Forecast:  The State of the Industry...and What's
      Ahead — Dynamics of the World Market."  Modern Paint and Coatings.
      January 1991, p. 39.
52.   Reference 14, p. 12-7.
53.   Reference 14, p. 12-7.
54.   Reference 14, p. 12-7.
55.   Reference 14, p. 12-7.
56.   Reference 14, p. 12-7.
57.   Reference 14, p. 12-8.
58.   Memorandum,  December 8, 1993, "Overall Cost Effectiveness of the
      Aerospace NESHAP," D. Hendricks, PES Inc., to V. Boothe, U.S. EPA:SDB.
59.   Memorandum.  January 13, 1994, D. Hendricks, PES Inc., to V. Boothe, U.S.
      EPA.
60.   Facsimile. December 27, 1993, D. Hendricks, PES, Inc., to T. Singh, JACA
      Corporation.
61.   Memorandum,  August 25, 1993, "MACT Cost Analysis for Primers and
      Topcoats," D. Hendricks, PES Inc., to V.  Boothe, EPA.
52.   Memorandum.  February 15, 1994, "Nationwide MACT Cost Analysis for The
      Control of Primer and Topcoat Inorganic Emissions, Depainting Inorganic
      Emissions, Wastewater Emissions, Storage Tank Emissions, and Waste
      Emissions," D. Hendricks, PES, Inc.,  to V. Boothe, U.S. EPA.
                                        9-82

-------
APPENDIX A.  DEVELOPMENT OF ENVIRONMENTAL IMPACTS
                 FOR MODEL PLANTS

-------
                                 MEMORANDUM
TO:                Vickie Boothe
                    US EPA: BSD

FROM:             David Hendricks
                    Pacific Environmental Services, Inc. (PES)

DATE:             December 30, 1993
                    L:\N208

SUBJECT:          Environmental Impacts for Chemical Milling Maskants
       The purpose of this memo is to compare baseline and MACT environmental
impacts for chemical milling maskants.  Baseline consists of a dip coating operation using
a solvent based maskant.  MACT floor specifies an emission rate of 1.3 pounds of HAP's
per gallon less water of maskant as applied, which is based on either the use of solvent
based maskant and a carbon adsorber to control emissions or the use of waterborne
maskants.

       Tables 1 and 2 summarize the environmental impacts.  The use of solvent based
maskants and a carbon adsorber (Table 1) is expected to result in an 80 percent reduction
in HAP emissions.  Additionally, increases in water, energy consumption, and  solid waste
generation of 435,290 gal/yr, 1,303,055 kW-hr/yr, and 8,700 Ib/yr, respectively, are
directly related  to the operation of the carbon adsorber.  The use of waterborne maskants
(Table 2) is expected to result in an 90 percent reduction in air emissions because of the
reduced solvent content of the waterborne maskants.  Additionally,  energy increases of
249,600 kW-hr/yr are directly  related to the operation of the curing oven. Finally, solid
waste increases of 7,590 to 16,520 Ib/yr are related to the solids content difference
between solvent based and waterborne maskants.  The assumptions  and calculations used in
deriving these impacts are detailed below.

       As defined in draft BID Chapter 6, chemical milling maskant operations occur only
in commercial/OEM, military/OEM,  and military/rework medium and large model plants.
Since there is no difference in  implementing MACT floor for commercial versus military
or OEM versus rework facilities, the  environmental analysis has been performed only for
different size model plants.

-------
Ms. Vickie Boothe
December 30, 1993
Page 2
                            TABLE 1
             ENVIRONMENTAL IMPACTS TO IMPLEMENT
       CHEMICAL MILLING MASKANT MACT - CARBON ADSORBER
Item
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Baseline HAP Emissions (Ib/yr)
MACT HAP Emissions - Carbon
Adsorber (Ib/yr)
MACT HAP Emission Reduction -
Carbon Adsorber (Ib/yr)
Baseline Wastewater Generation
(gal/yr)
MACT Wastewater Generation -
Carbon Adsorber (gal/yr)
MACT Implementation Wastewater
Generation - Carbon Adsorber (gal/yr)
Baseline Energy Consumption
(kWatt-hr/yr)
MACT Energy Consumption - Carbon
Adsorber
(kWatt-hr/yr)
MACT Implementation Energy
Consumption - Carbon Adsorber
(kWatt-hr/yr)
Baseline Solid Waste Generation
(Ib/yr)
MACT Solid Waste Generation -
Carbon Adsorber (Ib/yr)
MACT Implementation Solid Waste
Generation - Carbon Adsorber (Ib/yr)
Model Plant
Medium
78,000
15,600
62,400
0
435,290
435,290
0
1,303,055
1,303,055
40,560
49,260
8,700
Large
169,000
33,800
135,200
0
435,290
435,290
0
1,303,055
1,303,055
87,880
96,580
8,700

-------
Ms. Vickie Boothe
December 30, 1993
Page 3
                            TABLE 2

             ENVIRONMENTAL IMPACTS TO IMPLEMENT
     CHEMICAL MILLING MASKANT MACT - WATERBORNE MASKANT
Item
1.
2.
3.
4.
5.
6.
7.
8.
9.
Baseline HAP Emissions (Ib/yr)
MACT HAP Emissions - Waterborne
Maskants (Ib/yr)
MACT HAP Emission Reduction -
Waterborne Maskants (Ib/yr)
Baseline Energy Consumption
(kWatt-hr/yr)
MACT Energy Consumption -
Waterborne Maskants
(kWatt-hr/yr)
MACT Implementation Energy
Consumption - Waterborne Maskants
(kWatt-hr/yr)
Baseline Solid Waste Generation (Ib/yr)
MACT Solid Waste Generation -
Waterborne Maskants
(Ib/yr)
MACT Implementation Solid Waste
Generation - Waterborne Maskants
(Ib/yr)
Model Plant
Medium
78,000
7,640
70,360
0
249,600
249,600
40,560
48,150
7,590
Large
169,000
16,590
152,410
0
249,600
249,600
87,880
104,400
16,520

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Ms. Vickie Boothe
December 30,  1993
Page 4
BASELINE

Primary Air Emissions

       As stated previously, baseline chemical milling maskant application is a dip coating
operation using a solvent based maskant. The baseline usage of solvent based maskant was
obtained from the Section 114 questionnaire responses of a military/OEM/medium facility
and a military/OEM/large facility.  The baseline usage is 12,000 gal/yr for a medium
facility1, and 26,000 gal/yr for a large facility.2 The maskant usage for each model plant
multiplied by the baseline HAP content (6.5 Ib/gal) as listed in draft BID Chapter 6 gives
the baseline emission rate:

Medium model plant:  12,000 gal/yr x 6.5 Ib/gal - 78,000 Ib/yr

Large model plant:  26,000 gal/yr x 6.5 Ib/gal = 169,000 Ib/yr

Wastewater Generation and Energy Consumption

       The use of solvent based maskants does not impact a facility's water or energy use.

Solid Waste Generation

       According to two vendors,3'4 solvent based maskant appears to have an indefinite
life in a dip tank operation. Therefore, disposal of unused solvent based maskant will  not
be necessary.

       The dried maskant film that is removed from components after scribing and
chemical milling must be disposed of as waste. According to one vendor, a typical
solvent based maskant weighs 13 Ib/gallon and is 26 percent solids by weight.  Therefore,
the waste generated from dried maskant is:

Medium model plant: 12,000 gal/yr x  13 Ib/gal x 0.26  solids =  40,560 Ib  solids/yr

Large  model plant:  26,000 gal/yr x 13 Ib/gal x 0.26 solids =  87,880  Ib solids/yr


MACT IMPACTS - CARBON ADSORBER

       MACT for chemical milling maskant application  can be based on the  use of solvent
based maskant and a carbon adsorber to control emissions.  Since both the baseline and

-------
Ms. Vickie Boothe
December 30,  1993
Page 5
MACT scenarios are based on the use of solvent based maskant, the type of maskant,
usage, and dip application equipment remain the same and there are no incremental impacts
from these factors.  The only factor relevant in the impact analysis is the carbon adsorber.
Therefore, the air impact is the reduction in solvent emissions caused by the carbon
adsorber.  Additionally, water, energy,  and solid waste impacts are directly related to the
operation of the carbon adsorber.

Primary Air Emissions

      The primary air impact from using a carbon adsorber is a reduction in the HAP
emissions equivalent to baseline emissions multiplied by the overall control efficiency of
the carbon adsorber system.  The control efficiency needed to achieve the MACT emission
rate of 1.3 pounds of HAP's per gallon of maskant used less water is 80 percent.  This is
determined using the baseline emission rate of 6.5 Ib HAP/gal (solvent-based) and the
MACT emission rate of 1.3 Ib HAP/gal less water in the following equation:

6.5 Ib HAP/gal -  1.3 Ib HAP/gal   = 0.80
    6.5 Ib HAP/gal

The reduction in emissions is:

Medium model plant: 78,000 Ib/yr x 0.80  =  62,400 Ib/yr

Large model plant:  169,000 Ib/yr x 0.80 = 135,200 Ib/yr

Therefore, the MACT emissions are:

Medium model plant: 78,000 Ib/yr - 62,400 Ib/yr = 15,600 Ib/yr

Large model plant:  169,000 Ib/yr - 135,200 Ib/yr = 33,800 Ib/yr

Secondary Air Emissions

      Secondary air impacts are generated by the operation  of certain control systems.
For example, incineration may produce nitrogen oxides (NOX) and carbon monoxide (CO)
from the combustion of hydrocarbons.  In contrast, carbon adsorbers do  not cause any
secondary impacts.  The only emissions from a carbon adsorber are the original pollutants
present in the air stream that are not removed by the carbon  adsorber. These are taken
into account in the control efficiency of the device.   Additionally, secondary air impacts
are generated by the use of products that contain different or additional HAP's from  the

-------
Ms. Vickie Boothe
December 30, 1993
Page 6
baseline products.  No product substitutions are necessary for MACT.  Therefore, no
secondary air impacts are expected.

Wastewater Generation

       There are three possible sources of water effluent from carbon adsorbers: water
used to cool the inlet gas stream, cooling water used to condense the regenerate steam, and
the condensed regenerate steam.  Cooling the inlet gas stream will not be necessary  in this
case since the process is typically operated at ambient temperatures.  Therefore, this source
is eliminated.  Assuming that a regenerative carbon adsorption system is employed,  the
other two water sources will be present.

       The quantity of cooling water has been calculated using the EPA OAQPS Control
Cost Manual.6 The cooling water needed for either the medium or the large model plant
is approximately 12,447,000 gallons per year.  However, the cooling water for the
condenser does not come into contact with the contaminated steam; therefore, the water
does not become contaminated.  The cooling water can then be discharged directly from
the facility, or used in other operations within the facility.

       The quantity of regenerate steam, also calculated using the EPA OAQPS Control
Cost Manual,7 is 3,629,000 pounds per year for either the medium or the large model
plant, which is equivalent to 435,290 gallons of water per year.  The steam is used  to strip
the captured solvent from the carbon beds.  The steam is then condensed,  separated from
the solvent, and disposed of as wastewater.  The  solvent is typically reused in the maskant
process or sold back to the maskant manufacturer.

Energy Consumption

       Electricity will be consumed by the blower used to dry and cool the carbon beds, as
well as in the operation of the carbon adsorber fan and the water pump. The EPA OAQPS
Control Cost Manual8 has been used to calculate  the electricity usage for each. The
energy usage for the drying and cooling fan, the adsorber fan, and the water pump are
8,090, 161,775,  and 6,190 kilowatt-hr/yr, respectively.  Energy will also  be consumed in
the generation of the regenerate steam, which will most likely come from a gas fired
boiler.  The energy required to raise water from ambient temperature (60°F) to steam is
the latent heat of evaporation, which is approximately  1059.9 Btu/pound of steam
generated.  The quantity of steam need for the regeneration of the carbon is 3,629,OCG
pounds as detailed above in the water impacts section.  Therefore, the energy required to
produce the regenerate steam is:

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Ms. Vickie Boothe
December 30, 1993
Page?
1059.9 Btu/pound x 3,629,000 pounds/yr  =  3.85 x 109 Btu/year

3.85-x 109 Btu/year x 0.000293 kW-hr/Btu = 1,127,000 kW-hr/yr

Table 3 summarizes the energy impact of the carbon adsorber.

                                     TABLES
                  ENERGY  IMPACTS OF A CARBON ADSORBER
Item
1.
2.
3.
4.
Adsorber fan
Drying and cooling fan
Water pump
Steam generation
Total
Energy Impact
All Model Plants
(kW-hr/yr)
161,775
8,090
6,190
1,127,000
1,303,055
Solid Waste Generation

       The carbon beds must be replaced approximately every 5 years, resulting in the
disposal of hazardous waste.  The volume of carbon, calculated from the EPA OAQPS
Control Cost Manual,10 is 1,440 ft3/5 years or 290 ft3/yr.  The density of carbon is 25 to
35 Ib/ft3.11 Therefore, using the midpoint of 30 lb/ft3, the solid waste is 8,700 Ib/yr.
This solid waste is typically incinerated.

       As stated in the baseline section, solvent based maskant appears to have an
indefinite life in a dip tank operation.  Therefore, disposal of unused solvent based
maskant will not be necessary.

       The dried maskant film that is removed from components after scribing and
chemical milling must be disposed of as waste. The pounds of dried maskant film will be
the same as the pounds of baseline solid- waste. Therefore, there is no net impact from the
dried maskant. The total solid waste impact of implementing the MACT standard is equal
to the total MACT solid waste generation minus the total baseline solid waste generation.

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Ms. Vickie Soothe
December 30, 1993
Page 8
Medium model plant: 49,260 Ib/yr - 40,560 Ib/yr = 8,700 Ib/yr

Large model plant:  96,580 Ib/yr - 87,880 Ib/yr = 8,700 Ib/yr


MACT IMPACTS - WATERBORNE MASKANTS

      MACT for chemical milling maskant application can be based on the use of
waterborne maskants. Air impacts are related to a reduction in solvent in the waterborne
maskants. Additionally, energy impacts are related to the use  of curing ovens that are not
used in the baseline process of solvent based maskant. Solid waste impacts are related to
the thickness and solids content of waterborne maskants. There are no additional  water
impacts associated with the use of waterborne maskant compared to solvent based  maskant.

Primary Air Emissions

      There will be a reduction in HAP's emitted with the use of waterborne maskants
due to the replacement of solvents by water.  In order to accurately compare the reduction
in emissions, the equivalent volume of waterborne maskant that will replace the baseline
volume of solvent based maskant must be determined. The equivalent volume is calculated
on a solids applied basis utilizing the percent by volume of solids and the required dry
film  thickness  of each maskant.

      One vendor of solvent based maskants reported that a typical solvent based maskant
is 25 percent by volume solids and requires a 0.012 inch dry film thickness.   To
calculate the surface area coverage per gallon of maskant:

      1  square foot of surface area covered with a dry film thickness of 0.012 inches
      (0.001  feet) equates to a solids volume of 0.001  ft3.

1 ft2 surface area x 1  ft3  solids x Q.25  eal solids =  33 ft2
0.001 ft  solids   7.48 gal solids   gal maskant    gal maskant

      One vendor of waterborne  maskants reported that a typical waterborne maskant is
44 percent by  volume solids13 and requires a 0.019 inch dry film thickness.14 To
calculate the surface area coverage per gallon of maskant:

       1  square foot of surface area covered with a dry film thickness of 0.019 inches
      (0.0016 feet) equates to a solids volume of 0.0016 ft3.

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Ms. Vickie Boothe
December 30,  1993
Page 9
1 ft2 surface area x 1   ft3  solids x 0.44 gal solids =  37 ft2
0.0016 ft3 solids   7.48 gal solids    gal maskant   gal maskant


Surface area coverage (baseline):

Medium model plant:  12,000 gal maskant x 33 frugal maskant= 396,000 ft2

Large model plant:  26,000 gal maskant x 33 frugal maskant = 858,000 ft2


Equivalent waterborne maskant volume:

Medium model plant:  396,000 ft2/yr x 1 gal maskant/37 ft2  =  10,700 gal/yr

Large model plant:  858,000 ft^yr x 1 gal maskant/37 ft2  = 23,200 gal/yr

To calculate emissions, the waterborne maskant volumes need to be presented in gallons
less water per year.  One vendor stated that typical waterborne maskants contain 45 percent
by volume water.15 Therefore, the maskant usage less water is:

Medium model plant:  10,700 gal/yr - (10,700 gal/yr x 0.45) = 5,880 gal less water/yr

Large model plant:  23,200 gal/yr - (23,200 gal/yr x 0.45) =  12,760 gal less water/yr

With a HAP content of 1.3 Ib/gal less water, waterborne maskant emissions are:

Medium model plant:  5,880 gal less water/yr x 1.3 Ib/gal less water = 7,640 Ib/yr

Large model plant:   12,760 gal less water/yr x 1.3 Ib/gal less water = 16,590 Ib/yr

MACT primary air emission reductions are baseline primary air emissions minus MACT
primary air emissions:

Medium model plant:  78,000 Ib/yr - 7,640 Ib/yr = 70,360 Ib/yr

Large model plant:  169,000 Ib/yr - 16,590 ib/yr = 152,410  ib/yr

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Ms. Vickie Boothe
December 30, 1993
Page 10
Secondary Air Emissions

       Secondary air impacts are often generated by the operation of certain control
systems.  For example, incineration may produce nitrogen oxides (NOX) and carbon
monoxide (CO) from the combustion of hydrocarbons. The use of waterborne maskants
does not  require control equipment. Additionally, secondary air impacts are generated by
the use of products that contain different or additional HAP's from the baseline products.
Solvent based maskants typically  contain perchloroethylene.  In contrast, waterborne
maskants typically contain toluene or styrene.  Therefore, any  solvent emissions will differ
with the use of solvent based or waterborne maskants.  However, all of these solvents are
HAP's and are  taken into account in the primary air impacts.  Therefore, no additional
secondary air impacts are expected.
Wastewater Generation

       While waterborne maskants require water for dilution, one vendor stated that this
water will have a negligible effect on the overall water consumption of the model plants.
Consequently, water impacts were assumed to be negligible.

Energy Consumption
       Waterborne maskants require a final bake to cure the coating.  Facilities would
have to install ovens for this purpose, which will consume energy.  According to one
vendor, an oven (6f x 10' x 6' deep) that runs at 500°F consumes 60 kilowatts.17  The
ovens typically used in the chemical milling maskant curing process are larger and run at
lower temperatures.  However, this energy requirement will be used for this energy impact
estimation. Two ovens are typically run 6 to 8 hours a day, 5 days a week, and 52 weeks
a year.18'19  Assuming the worst case where the ovens run 8 hours per day, or 2,080
hours per year, the energy requirement for the oven is:

60 kilowatts x 2,080 hr/yr x 2 ovens = 249,600 kilowatt-hr/yr

Solid Waste Generation

       According to one vendor,   waterborne maskant appears to have an indefinite life
in a dip tank operation with proper maintenance.  According to another vendor,
waterborne maskant has a limited sheif iife.  However, as this second vendor noted,
waterborne maskants have not been in service at any facility long enough to determine a
probable shelf life.  Therefore, it will be assumed that disposal of unused waterborne
maskant from a dip tank operation will not be necessary.

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Ms. Vickie Boothe
December 30,  1993
Page 11
      The dried maskant film that is removed from components after drying and chemical
milling must be disposed of as waste. According to one vendor, 2 a typical waterborne
maskant has 4.0 to 4.8 pounds of solids per gallon of coating.  A second vendor stated
that their two coat system has an average of 4.7 pounds of solids per gallon of coating.
An average of 4.5 pounds of solids per gallon will be used in the calculations. Total solid
waste disposal for MACT is:

Medium model plant:  10,700 gal/yr x 4.5 Ib solids/gal = 48,150 Ib solids/yr

Large model plant:  23,200 gal/yr x 4.5 Ib solids/gal  =  104,400 Ib solids/yr

The MACT solid  waste impact is then the amount of solid waste generated by MACT
minus the baseline solid waste:

Medium model plant:  48,150 Ib solids/yr - 40,560 Ib  solids/yr = 7,590 Ib solids/yr

Large model plant:  104,400 Ib  solids/yr - 87,880 Ib solids/yr = 16,520 Ib solids/yr


References

 1.   Section 114 Questionnaire Response from Grumman Corporation in Bethpage, New
      York.

 2.   Section 114 Questionnaire Response from McDonnell Douglas Corporation in St.
      Louis, Missouri.

 3.   Telephone Report.  K. Feser, PES, and S. Weinstein, AC Products, on March 11,
      1993.

 4.   Telephone Report.  K. Feser, PES, and M.  Jaffari, Malek, Inc., on March 12, 1993.

 5.   Telephone Report.  K. Feser, PES, and S. Weinstein, AC Products, on March 12,
      1993.

 6.   OAOPS Control Cost Manual. Fourth Edition, EPA-450/3-90-006, January 1990.
      pp.  4-28 - 4-29.

 7.   Reference 6.  pp. 4-28.

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Ms. Vickie Boothe
December 30, 1993
Page 12
 8.   Reference 6.  pp. 4-29 - 4-31.

 9.   McCabe, W. and J. Smith. Unit Operations of Chemical Engineering. Third Edition,
     McGraw-Hill Book Company, 1976. Appendix 8.

10.   Reference 6.  pp. 4-32.

11.   Perry, Robert H. and Cecil H. Chilton, Chemical Engineers' Handbook. 5th Edition,
     McGraw-Hill Book Company, 1973. p. 16-5.

12.   Telephone Report.  K. Feser, PES, and S. Weinstein, AC Products, on December
     15, 1992.

13.   Telephone Report.  K. Feser, PES, and M. Jaffari, Malek, Inc., on November 11,
     1992.

14.   "The Costs of Using Solvent Based Maskants Versus CAX-100-LA, a Waterborne
     Maskant," Product Brochure of Malek, Inc. p. 3.

15.   Letter.  C. Jaffari, Caspian, to V. Boothe, EPA:ESD.  August 30, 1993.  Discussion
     on waterborne maskant emission rate.

16.   Reference 3.

17.   Telephone Report.  K. Feser, PES, and P. Averett, Photo Chemical Systems, on
     February 24,  1992.

18.   Reference 13.

19.   "World's Largest Manufacturer of Chemical Milling Maskants and Chemical
     Processing Coatings."  AC Products, Inc. Company Information.

20.   Reference 4.

21.   Reference 3.

22.   Telephone Report.  K. Feser, PES, and M. Jaffari, Malek, Inc., on March 16,  1992.

23.   Reference 5.

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                           MEMORANDUM
TO:       Vickie Boothe
          US £PA:ESD

FROM:     David Hendricks
          Pacific Environmental Services, Inc. (PES)

DATE:     August 25, 1993
          L:\N019

SUBJECT:  Environmental Impacts for Aircraft Depainting


     The purpose of this memo is to calculate and compare
baseline and MACT environmental impacts for aircraft depainting.
Baseline consists of using methylene chloride based chemical
strippers.  The MACT floor specifies no HAP emissions from
chemical depainting.  Three basic methods have been identified
for meeting the MACT floor.  These methods are (1) media blasting
such as plastic and wheat starch; (2) both acidic and alkaline
non-HAP chemical strippers; and (3) reducing the amount of outer
surface area of the aircraft that is coated.  The data for the
first option was derived mainly from military facilities.  Since
it is unknown whether the available data is applicable to
commercial facilities, the environmental impacts for the first
option were evaluated only for military model plants.  Similarly,
the available data for the second and third options was derived
from commercial facilities.  Since it is unknown whether the
available data is applicable to military facilities, and the
third option applies only to commercial aircraft, the
environmental impacts for the second and third options were
evaluated only for commercial model plants.  All impact analyses
also include an exemption of 20 gallons of chemical stripper per
aircraft for spot stripping and decal removal.

     Tables 1, 2, and 3 summarize the baseline and MACT
environmental impacts for each of the options.  The assumptions
and calculations used in determining these impacts are detailed
below.

     The implementation of the first option is expected to result
in a 98 percent reduction in air emissions and a 100 percent
reduction in water emissions.  Additionally, solid waste will be
increased 4.8 times.  Energy usage will increase by 300,000 to

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Ms. Vickie Boothe
August 25, 1993
Page 2
                             TABLE  1

   ENVIRONMENTAL IMPACTS OF IMPLEMENTING PLASTIC MEDIA BLASTING
Item
1. Baseline Emissions
(Ibs/yr)
2. MACT Emissions
(Ibs/yr)
3. MACT Emission
Reduction (Ibs/yr)
4. Baseline Wastewater
Generation
(gal/yr)
5. MACT Wastewater
Generation (gal/yr)
6. MACT Implementation
Wastewater
Reductions (gal/yr)
7. Baseline Energy
Consumption
(kW-hr/yr)
8 . MACT -Energy
Consumption
(kW-hr/yr)
9 . MACT Implementation
Energy Consumption
(kW-hr/yr)
Model Plant
Small
425,700
13,230
412,470
1,516,900
0
1,516,900
0
308,620
308,620
Medium
588,070
14,700
573,370
2,095,500
0
2,095,500
0
426,340
426,340
Large
3,185,780
22,050
3,163,730
11,352,000
0
11,352,000
0
2,309,620
2,309,620

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Ms. Vickie Boothe
August 25, 1993
Page 3
                        TABLE 1 CONTINUED
Item
10. Baseline Solid
Waste Generation
(Ibs/yr)
11. MACT Solid Waste
Generation (Ibs/yr)
12 . MACT Implementation
Solid Waste
Generation (Ibs/yr)
Model Plant
Small
41,990
248,980
206,990
Medium
58,010
340,020
282,010
Large
314,240
1,778,650
1,464,410

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Ms. Vickie Boothe
August 25, 1993
Page 4
                            ' TABLE 2

     ENVIRONMENTAL IMPACTS OF IMPLEMENTING NON-HAP STRIPPERS
Item
1.
2.
3.
4.
5.
6.
7.
8.
9.
Baseline HAP Emissions
(lb/yr)
MACT HAP Emissions
(lb/yr)
MACT HAP Emission Reduction
(lb/yr)
Baseline Wastewater
Generation (gal/yr)
MACT Wastewater Generation
(gal/yr )
MACT Implementation
Wastewater Reductions (gal/yr)
Baseline Solid Waste
Generation (gal/yr)
MACT Solid Waste Generation
(gal/yr)
MACT Implementation Solid
Waste Generation (gal/yr)
Model Plant
Small
44,540
2,500
42,040
19,670
200
19,470
4,670
6,890
2,220
Medium
133,180
6,760
126,420
58,750
530
58,220
13,950
20,560
6,610

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Ms. Vickie Boothe
August 25, 1993
Page 5
                             TABLE 3

 ENVIRONMENTAL IMPACTS OF REDUCING THE OUTER SURFACE AREA OF THE
                     AIRCRAFT THAT IS COATED
Item
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Baseline HAP Emissions (Ib/yr)
MACT HAP Emissions (Ib/yr)
MACT HAP Emission Reduction
(Ib/yr)
Secondary Air Emissions -
Baseline Repainting (Ib/yr)
Secondary Air Emissions - MACT
Repainting (Ib/yr)
Secondary Air Emission
Reduction - MACT
Implementation (Ib/yr)
Baseline Wastewater Generation
(gal/yr)
MACT Wastewater Generation
(gal/yr)
MACT Implementation Wastewater
Reductions (gal/yr)
Baseline Solid Waste
Generation (gal/yr)
MACT Solid Waste Generation
(gal/yr)
MACT Implementation Solid
Waste Reductions (gal/yr)
Model Plant
Small
44,540
2,500
42,040
4,470
220
4,250
19,670
980
18,690
4,670
230
4,440
Medium
133,180
6,760
126,420
13,800
690
13,110
58,750
2,940
55,810
13,950
700
13,250

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Ms. Vickie Boothe
August 25, 1993
Page 6
3,000,000 kilowatt-hours per year depending on the size of the
model plant.

     The implementation of the second option is expected to
result in a 94 percent reduction in air emissions.  Additionally,
this option is expected to reduce wastewater by 99 percent and
increase solid waste by 47 percent.

     The implementation of the third option is expected to result
in a. 94 percent reduction in air emissions.  Additionally, this
option is expected to reduce secondary air emissions, wastewater,
and solid waste by 95 percent.


OPTION 1 - PLASTIC MEDIA BLASTING

BASELINE

     Baseline has been defined as depainting fully painted
aircraft with methylene chloride based strippers with no emission
controls in place.  Many military facilities are currently using
plastic media blasting.  Therefore, for the purpose of this
option, data from military facilities will be used for both
baseline and MACT.  The total outer surface area of aircraft
reworked annually for each military model plant is:

     Small model plant1:  137,900 ft2/yr

     Medium model plant2'3:  190,500 ft2/yr

     Large model plant4:  1,032,000 ft2/yr

Primary Air Emissions

     From data provided by Robins Air Force Base  (AFB)5, it takes
0.42 gal/ft2 to depaint military aircraft using methylene
chloride based strippers.  The density of a typical methylene
chloride stripper is  10.5 pounds per gallon and 70 percent of the
stripper by weight  is methylene chloride.6  The other 30 percent
is  typically soaps, detergents, water, or non-HAP acids.   It is
assumed from information  in  the Section 114 responses that 100
percent of the methylene  chloride  is lost as air emissions.8  The
baseline emissions  of  stripper by model plant  are:

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Ms. Vickie Boothe
August 25, 1993
Page 7
Small model plant:  137,900 ft2/yr x 0.42 gal/ft2 x 10.5  Ib/gal
                                        x 0.7 « 425,700  Ib/yr

Medium model plant:  190,500 ft2/yr x 0.42 gal/ft2 x  10.5 Ib/gal
                                        x 0.7 - 588,070  Ib/yr

Large model plant:  1,032,000 ft2/yr x 0.42 gal/ft2 x 10.5 Ib/gal
                                        x 0.7 = 3,185,780 Ib/yr

Wastewater Generation

     The baseline method of depainting involves the  use  of
methylene chloride based strippers  followed by a water rinse.
The volume of the rinse water has been quantified by both
Lockheed Ontario and Robins AFB.  Lockheed Ontario uses
approximately 6 gallons of rinse water per square foot of
aircraft stripped.9  Robins AFB reports a range of 8 to 25
gallons per square foot,10 the midpoint being  16 gal/ft2.
Therefore, an industry average of approximately 11 gallons of
rinse water is used per square foot of aircraft stripped.  The
baseline gallons of rinse water by  model plant are:

Small model plant:  137,900 ft2/yr x 11 gal/ft2 =
                                    1,516,900  gal/yr

Medium model plant:  190,500 ft2/yr x 11 gal/ft2 =
                                    2,095,500  gal/yr

Large model plant:  1,032,000 ft2/yr x 11 gal/ft2 =
                                    11,352,000 gal/yr

Energy Consumption

     Other than a ventilation system, the baseline method of
depainting consumes very little energy.  Therefore,  the  energy
consumption of methylene chloride based  depainting  is assumed to
be insignificant compared to the energy  consumption  of the
facility as a whole.

Solid Waste Generation

     The baseline methylene chloride based depainting process
produces a spent stripper sludge that must be disposed.   The
sludge may be treated on-site or  shipped off-site for disposal.
No data on _waste disposal is available from military facilities.
Delta Air Lines specified that 0.029 gallons  of waste stripper  is
disposed of per square  foot of surface area stripped.11'12  Tiia
density of a typical methylene chloride  stripper is  10.5 pounds

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Ms. Vickie Boothe
August 25, 1993
Page 8
per gallon.  Assuming that the density of the waste stripper is
approximately equal to the density of the original stripper, the
baseline pounds of solid waste disposed by model plant are:

Small model plant:  137,900 ft2/yr x 0.029 gal/ft2 x 10.5 Ib/gal
                                        = 41,990 Ib/yr

Medium model plant:  190,500 ft2/yr x 0.029 gal/ft2 x  10.5  Ib/gal
                                        = 58,010 Ib/yr

Large model plant: 1,032,000 ft2/yr x 0.029 gal/ft2 x  10.5  Ib/gal
                                        = 314,240 Ib/yr

MACT

     As previously stated, the MACT floor specifies no HAP
emissions  from chemical depainting.  This can be achieved  through
the use of dry media blasting techniques.  Additionally, the
regulation includes an exemption of 20 gallons of stripper per
airplane stripped.  As a result of MACT, HAP air emissions and
wastewater generation will be virtually eliminated.   Energy usage
will increase due to electrical consumption by the blasting
equipment.  Solid waste generated will be in the form of paint
chips and  spent plastic media rather than spent stripper sludge.

Primary Air Emissions

     The MACT standards are expected to virtually eliminate HAP
emissions  with the use of plastic media blasting.  MACT air
emissions  will equal the approximate number of aircraft stripped
per model  plant13-14'15 multiplied by the 20 gallon exemption.  As
stated in  the baseline section, the density of a typical
methylene  chloride stripper is 10.5 pounds per gallon and  70
percent of the stripper by weight  is methylene chloride.   The
other 30 percent  is typically soaps, detergents, water, or non-
HAP acids.  Additionally, it is assumed from information in the
Section 114 responses that 100 percent of the methylene chloride
is lost as air emissions.  The HAP emissions by model plant ara:

Small model plant:  90 aircraft/yr x 20 gal x 10.5 Ib/gal
                                        x  0.7 - 13,230 Ib/yr

Medium model plant:  100 aircraft/yr x 20 gal x 10.5  Ib/gal
                                        x  0.7 - 14,700 Ib/yr

Large model plant:   150  aircraft/yr x 20  gal x  10.5 Ib/gal
                                        x 0.7 = 22,050 Ib/yr

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Ms. Vickie Boothe
August 25, 1993
Page 9
The reduction in emissions will be equivalent to the baseline
emissions minus the MACT air emissions:

Small model plant:  425,700 Ib/yr - 13,230 Ib/yr = 412,470 Ib/yr

Medium model plant:  588,070 Ib/yr - 14,700 Ib/yr = 573,370 Ib/yr

Large model plant:  3,185,780 Ib/yr - 22,050 Ib/yr = 3,163,730 Ib/yr

Secondary Air Emissions

     Secondary air emissions are generated by the operation of
certain control systems.  For example, incineration may produce
nitrogen oxides (NOX)  and carbon monoxide (CO)  from the
combustion of hydrocarbons.  Additionally, secondary air
emissions are generated by the use of products that contain
different or additional HAP's from the baseline products.  The
use of plastic media blasting does not require control equipment
or product substitutions.  However, a small amount of HAP
emissions occur in the form of particulates from the blasting
process.  These particulates contain inorganic HAP components of
the paint such as. chromium and cadmium.  The level of these
emissions has not been quantified, but is believed to be very
small compared to overall baseline emissions.  Therefore,
secondary air emissions are expected to be insignificant.

Wastewater Generation

     Assuming a complete switch to plastic media blasting, the
baseline rinse water usage would be eliminated.  Water would be
used only to rinse the areas stripped with the exempt 20 gallons
of chemical stripper.  As this 20 gallons can be used to strip
any area on the aircraft, the square footage stripped is
difficult to quantify, but is expected to be insignificant
compared to the baseline wastewater generated.  Therefore, the
reduction in wastewater will be equivalent to the baseline
wastewater disposal:

Small model plant:  1,516,900 gal/yr wastewater reduced

Medium model plant:  2,095,500 gal/yr wastewater reduced

Large model plant:  11,352,000 gal/yr wastewater reduced

Energy Consumption

     The plastic  sedia blasting systems  consume electricity.
According to Lockheed Ontario, 6 their  plastic Tnedia blasting

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Ms. Vickie Boothe
August 25, 1993
Page 10
equipment requires a 100 horsepower air compressor system.
Lockheed also stated that it takes approximately 0.03 hours to
strip a square foot of aircraft.17 Therefore, the energy used
per model plant is:

Small model plant: 100 hp x 0.746 kW/hp x 0.03 hr/ft2
                         x 137,900 ft2/yr =  308,620 kw-hr/yr

Medium model plant: 100 hp x 0.746 kW/hp x 0.03 hr/ft2
                         x 190,500 fts/yr =  426,340 kW-hr/yr

Large model plant: 100 hp x 0.746 kW/hp x 0.03 hr/ft2
                         x 1,032,000 ft2/yr =  2,309,620 kW-hr/yr

Solid Waste Generation

     The blasting process produces paint chips mixed with some
blasting media.  Due to the metal content of the paint  chips,
this must be disposed of as a hazardous waste.  The typical
method of disposal is by landfill.  According to Robins AFB,18 an
estimate of the amount of paint  chips produced per square foot
stripped is 0.15 to 0.25 pounds.  Additionally, approximately 1.5
pounds per square foot is lost as waste.19  Therefore,  the solid
waste generated by plastic media blasting is approximately 1.7
pounds/ft2.  The pounds of solid waste by model plant are:

Small model plant:  137,900 ft2/yr x 1.7 lb/ft2 =  234,430 Ib/yr

Medium model plant:  190,500 ft2/yr x 1.7 lb/ft2 = 323,850 Ib/yr

Large model plant:  1,032,000 ftz/yr x 1.7 lb/ft2  =  1,754,400  Ib/yr

Additionally,  solid waste is generated  from the use of  the 20 gallons
of exempt  stripper.  Delta Air Lines specified that 0.77 gallons of
stripper waste is disposed of per gallon of original stripper used.20
Using the  original chemical stripper density of 10.5 Ib/gal, the
pounds of  solid waste by model plant are:

Small model plant:  90 aircraft/yr x 20 gal stripper/aircraft x
           0.77 gal waste/gal stripper x 10.5 Ib/gal =  14,550 Ib/yr

Medium model plant:  100 aircraft/yr x  20 gal stripper/aircraft x
           0.77 gal waste/gal stripper x 10.5 Ib/gal =  16,170  Ib/yr

Large model plant:  150 aircraft/yr x 20 gal stripper/aircraft  x
           0.77 gal waste/gal stripper x 10.5 Ib/gal =  24,250  Ib/yr

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Ms. Vickie Boothe
August 25, 1993
Page 11
The total MACT solid waste generated is:

Small model plant:  234,430 Ib/yr + 14,550 Ib/yr = 248,980 Ib/yr

Medium model plant:  323,850 Ib/yr + 16,170 Ib/yr = 340,020 Ib/yr

Large model plant:  1,754,400 Ib/yr + 24,250 Ib/yr = 1,778,650 Ib/yr

Therefore, the increase in solid waste with the implementation of MACT
is the amount of solid waste generated by the MACT solid waste minus
the baseline solid waste:

Small model plant:  248,980 Ib/yr - 41,990 Ib/yr = 206,990 Ib/yr

Medium model plant:  340,020 Ib/yr - 58,010 Ib/yr = 282,010 Ib/yr

Large model plant: 1,778,650 Ib/yr - 314,240 Ib/yr = 1,464,410 Ib/yr


Noise Generation

     Blasting equipment generates noise during the. operation of
the air compressor and the blasting nozzles.  However, this noise
impact is expected to be  insignificant when compared to the model
plant as a whole.  Therefore, it is expected that the overall
effect of increased noise volume is negligible.


OPTION 2 - NON-HAP STRIPPER AND
OPTION 3 - REDUCED PAINT  SCHEME

BASELINE

     The baseline for Options 2 and 3 has been defined as
depainting fully-painted  aircraft with methylene chloride based
chemical strippers.  Since Option 2 and 3 are demonstrated at
commercial facilities, data for the baseline has been obtained
from commercial facilities.  The following parameters define
baseline:

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Ms. Vickie Booths
August 25, 1993
Page 12
Total number of aircraft reworked annually

     Small model plant        -    17 narrow body

     Medium model plant21-22    -    35 narrow body
                                   11 wide body

The number of aircraft reworked annually for the small  model
plant was extrapolated from the medium model plant  data.   Total
outer surface area of aircraft reworked annually:

     Small model plant23       -  163,900 ft2

     Medium model plant24      -  489,610 ft2

Primary Air Emissions

     From data provided by TWA and Delta, it takes  0.037  gal/ft2
to depaint aircraft using methylene  chloride based  strippers.25-26
Baseline stripper usage was calculated using these  data and the
baseline outer surface area per model plant.  As stated in Option
1, the density of a typical methylene chloride stripper is 10.5
pounds per gallon, and 70 percent of the stripper by weight is
methylene chloride. The other 30 percent is typically soaps,
detergents, water, or non-HAP acids.  Additionally,  Delta Air
Lines specified that 0.77 gallons of stripper waste is  disposed
of per gallon of original stripper used.

Stripper usage and disposal:

Small model plant:  163,900 ft2/yr x 0.037 gal/ft2  = 6,060 gal/yr

                    6,060 gal/yr x 0.77 = 4,670 gal for disposal

Medium model plant: 489,610 ft2/yr x 0.037 gal/ft2  = 18,120 gal/yr

                    18,120 gal/yr x  0.77 =  13,950 gal for disposal

Stripper Emissions  (assuming  100 percent of the methylene chloride  is
emitted):

Small model plant:   6,060 gal/yr x  10.5 Ib/gal x  0.7 =  44,540  Ib/yr

Medium model plant: 18,120 gal/yr x  10.5 Ib/gal x  0.7 = 133,180

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Ms. Vickie Booths
August 25, 1993
Page 13
Wastewater Generation

     According to United Airlines in San Francisco, approximately
100,000 gallons of wastewater were generated from their
depainting operations in 1990.27  United Airlines depainted
approximately 856,000 ft2 of surface area  during this year,
resulting in the generation of 0.12 gallons of wastewater per
square foot of outer surface area.28  Applying this  rate to the
small and medium model plants:

Baseline Wastewater:

Small model plant: 163,900 ft2/yr x 0.12 gal/ft2 -  19,670 gal/yr

Medium model plant: 489,610 ft2/yr x 0.12  gal/ft2 =  58,750 gal/yr


OPTION 2 - NON-HAP STRIPPER

MACT IMPACTS

     As stated previously, this  option is based on  using non-HAP
strippers.  At least one commercial facility uses non-HAP
strippers to depaint aircraft.   Data from this facility will be
used for the purpose of this option.  Additionally, 20 gallons of
chemical stripper per aircraft stripped will be allowed as an
exemption.  As a result of MACT, air emissions, wastewater, and
solid waste will be reduced.

Primary Air Emissions

     The MACT standards are expected to virtually eliminate HAP
emissions with the use of non-HAP strippers.  Since the total
number of aircraft reworked annually is 17 for a small model
plant and 46 for a medium model  plant, MACT air emissions will
equal the approximate number of  aircraft stripped per model plant
multiplied by the 20 gallon exemption.  As stated  in  the Option 1
baseline section, the density of a typical methylene  chloride
stripper is 10.5 pounds per gallon and 70 percent of  the stripper
by weight is methylene chloride.  Additionally, it  is assumed
that 100 percent of the methylene chloride is lost  as air
emissions.  The MACT emissions of stripper by model plant are:

Small model plant:  17 aircraft/yr x 20 gal x 10.5  Ib/gal
                                   x 0.7 = 2,500 Ib/yr

Medium model plant:  46 aircraft/yr x 20 gal x 10.5 Ib/gal
                                   x 0.7 = 6,760 Ib/yr

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Ms.  Vickie Boothe
August 25, 1993
Page 14
 The reduction in emissions will  be  equivalent to the baseline
 emissions minus the MACT  air  emissions:

 Small model plant:  44,540 Ib/yr -  2,500 Ib/yr = 42,040  Ib/yr

 Medium model plant:   133,180  Ib/yr  -  6,760 Ib/yr =  126,420  Ib/yr

 Secondary Air Emissions

      Secondary air emissions  are often generated by the  operation
 of certain control systems.   For example, incineration may
 produce nitrogen oxides  (NOX) and carbon monoxide (CO) from the
 combustion of hydrocarbons.   Additionally, secondary  air
 emissions are generated by the use  of products that contain
•different or additional HAP's from  the baseline products.   The
 MACT floor does not require  control equipment and stripper
 substitutions must be non-HAP products.  Some non-HAP strippers
 currently in use contain  VOC. One  non-HAP stripper has  a VOC
 limit of 3.33 pounds  per  gallon  of  stripper.29  However,  the
 stripper has an evaporation  limit less than  one and a very  low
 vapor pressure.  It is expected  that  VOC emissions  from  this
 stripper are very low and associated  secondary air  emissions
 would be insignificant.

 Wastewater Generation

      The MACT method  of depainting  involves  the use of non-HAP
 strippers followed by a water rinse.  The volume of the  rinse
 water has been quantified by Delta  Airlines.  Delta uses
 approximately 0.58 gallons of rinse water per gallon  of  non-HAP
 stripper used.30  Assuming that  each facility uses  the allowed  20
 gallons of stripper,  the  MACT gallons of rinse water  by  model
 plant are:

 Small model plant:   17 aircraft/yr  x  20 gal  stripper/aircraft
                    stripped x  0.58 gal water/gal stripper
                                        = 200 gal/yr

 Medium model plant:   46  aircraft/yr x 20 gal stripper/aircraft
                     stripped x  0.58 gal water/gal stripper
                                        =530 gal/yr

 The water impact is then calculated by subtracting  the amount of
 wastewater generated  by  MACT from that generated by baseline:

 Small model plant:   19,670  gal/yr - 200 gal/yr =  19,470  gal/yr

 Medium model plant:   58,750  gal/yr  -  530 gal/yr =  58,220 gal/yr

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Ms. Vickie Boothe
August 25, 1993
Page 15
Energy Consumption

     Other than a ventilation system, the non-HAP stripper method
of depainting consumes very little energy.  Therefore, the energy
impact of non-HAP depainting is assumed to be insignificant
compared to the energy consumption of the facility as a whole.

Solid Waste Generation

     The non-HAP depainting process produces a spent stripper
sludge that must be disposed.  The sludge may be treated on-site
in a standard wastewater treatment facility.  A Delta Airlines
representative stated that very little of the non-HAP stripper
evaporates31 and 0.042 gallons of stripper is used per square
foot of aircraft stripped.32  Assuming that  all of the stripper
is disposed as waste, the baseline pounds of solid waste disposed
by model plant are:

Small model plant:  163,900 ft2/yr x 0.042 gal/ft2 = 6,890 gal/yr

Medium model plant:  489,610 ft2/yr x 0.042  gal/ft2 = 20,560 gal/yr

     The solid waste impact is then calculated by subtracting the
amount of solid waste generated by baseline from that generated
by MACT:

Small model plant:  6,890 gal/yr - 4,670 gal/yr = 2,220 gal/yr

Medium model plant:  20,560 gal/yr - 13,950 gal/yr = 6,610 gal/yr


OPTION 3 - REDUCED PAINT SCHEME

MACT IMPACTS

     As stated previously, this option is based on partially
painting the aircraft and polishing the unpainted bare metal
portion of the aircraft.  As a result of MACT, air emissions,
wastewater, and solid waste will be reduced.  This option is
demonstrated at commercial facilities and data from these
facilities are used below.

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Ms. Vickie Boothe
August 25, 1993
Page 16
Primary Air Emissions

     The MACT standards are expected to virtually eliminate HAP
emissions with the use of the reduced paint scheme.  Facilities
that currently use a reduced paint scheme are able to hand sand
the tail and speed stripes, areas that are reworked during a
typical maintenance stop.  The wings, which are typically
painted, are seldom stripped.  Therefore, the 20 gallon exemption
is adequate for decal and spot stripping.  Since the total number
of aircraft reworked annually is 17 for a small model plant and
46 for a medium model plant, MACT air emissions will equal the
approximate number of aircraft stripped per model plant
multiplied by the 20 gallon exemption.  As stated in the baseline
section, the density of a typical methylene chloride stripper is
10.5 pounds per gallon and 70 percent of the stripper by weight
is methylene chloride.  Additionally, it is assumed that 100
percent of the methylene chloride is lost as air emissions.  The
MACT emissions of stripper by model plant are:

Small model plant:  17 aircraft/yr x 20 gal x 10.5 Ib/gal
                                   x 0.7 = 2,500 Ib/yr

Medium model plant:  46 aircraft/yr x 20 gal x 10.5 Ib/gal
                                   x 0.7 = 6,760 Ib/yr

The reduction in emissions will be equivalent to the baseline
emissions minus the MACT air emissions:

Small model plant:  44,540 Ib/yr - 2,500 Ib/yr = 42,040 Ib/yr

Medium model plant:  133,180 Ib/yr - 6,760 Ib/yr = 126,420 Ib/yr

Secondary Air Emissions

     Secondary air emissions are often generated by the operation
of certain control systems.  For example, incineration may
produce nitrogen oxides  (NOX) and carbon monoxide (CO)  from the
combustion of hydrocarbons.  Additionally, secondary air
emissions are generated by the use of products that contain
different or additional HAP's from the baseline products.  The
MACT floor does not require  control  equipment.  However, the
regulations may result in the use of a polish on the unpainted
portions of the aircraft.  A polish  is currently demonstrated in
the  industry that contains no HAP's.33 A polish  used by a  second
facility contains 35 percent kerosene.34   Kerosene,  a derivative
of petroleum, typically  contains a majority of aliphatic
h.vd.2rocs»2rbons,  Anv HAP's that ssy be  in  the kerossne  (typically

-------
Ms. Vickie Booths
August 25, 1993
Page 17
aromatic hydrocarbons) are in very small quantities and may be
considered insignificant.

     Another secondary impact affected by this option is the
reduced emissions from repainting.  Reworking an aircraft
includes repainting as well as stripping and a reduced paint
scheme reduces the amount of paint and, therefore, the amount of
emissions from the paint.  Based on information presented in the
September 1991 issue of Industrial Finishing concerning Boeing's
Seattle operations, 125 gallons of paint are required for a
completely painted narrow body aircraft and 200 gallons for a
completely painted wide body aircraft.35

Baseline Paint Usage:

Small model plant:  17 narrow body/yr x 125 gal/narrow body =
                                                   2,130 gal/yr

Medium model plant:  35 narrow body/yr x 125 gal/narrow body +
                  11 wide body/yr x 200 gal/wide body =
                                                   6,570 gal/yr

     Using a weighted average HAP content of 2.1 Ibs/gal for the
primer and topcoat as determined from Section  114  questionnaire
data, the annual emissions from repainting of  fully-painted
aircraft are:

Small model plant:    2,130 gal/yr x 2.1 Ibs/gal =  4,470 Ibs/yr

Medium model plant:   6,570 gal/yr x 2.1 Ibs/gal = 13,800 Ibs/yr

     USAir, one of the principal airlines using aircraft with
unpainted aluminum clad outer skins, leaves 95 percent of the
total outer surface of the aircraft uncoated.36 Assuming that  95
percent of the outer surface is unpainted and  applying that
percentage to the baseline repainting emissions gives the MACT
emissions.

Small model plant:  4,470 Ibs/yr x  (1-0.95) =   220  Ibs/yr

Medium model plant:   13,800 Ibs/yr x  (1-0.95)  =690  Ibs/yr

The impact is then calculated by subtracting the emissions
generated by MACT  from that generated by baseline:

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Ms. Vickie Booths
August 25, 1993
Page 18
Small model plant:  4,470 Ibs/yr - 220 Ibs/yr = 4,250 Ibs/yr

Medium model plant:  13,800 Ibs/yr - 690 Ibs/yr = 13,110 Ibs/yr


Wastewater Generation

     As stated above, USAir leaves 95 percent of the total outer
surface of the aircraft uncoated.  Assuming that 95 percent of
the outer surface is unpainted and applying that percentage to
the baseline wastewater disposal gives the MACT wastewater
disposal.

Small model plant:  19,670 gal/yr x  (1-0.95) =   980 gal/yr

Medium model plant: 58,750 gal/yr x  (1-0.95) = 2,940 gal/yr

The water impact is then calculated by subtracting the amount of
wastewater generated by MACT from that generated by baseline:

Small model plant:  19,670 gal/yr - 980 gal/yr = 18,690 gal/yr

Medium model plant:  58,750 gal/yr - 2,940 gal/yr = 55,810 gal/yr

Energy Consumption

     Since the generation of wastewater and solid waste decreases
under MACT, the energy consumed  in the treatment and disposal of
the waste will also decrease proportionally.  However, no data
were available to quantify this  reduction in energy consumption.

Solid Waste Generation

     Similar to water impacts, assuming that 95 percent of the
outer surface is unpainted and applying that percentage to the
baseline solid waste disposal gives the MACT solid waste
disposal.

Small model plant:  4,670 gal/yr x  (1-0.95) = 230 gal/yr

Medium model plant:  13,950 gal/yr x  (1-0.95) = 700 gal/yr

     Solid waste  is also generated from the repainting process.
However, the amount of solid waste cannot be quantified since  it
is directly related to the work  practice standards of each
facility.  For the purpose of this analysis, the  solid waste
crerisra.tsd from rs^sintirK7 was assumed to bs nerfli'CIih>l|2 =

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Ms. Vickie Boothe
August 25, 1993
Page 19
     The solid waste impact is then calculated by subtracting the
amount of solid waste generated by MACT from that generated by
baseline:

Small model plant:  4,670 gal/yr - 230 gal/yr = 4,440 gal/yr

Medium model plant:  13,950 gal/yr - 700 gal/yr = 13,250 gal/yr


References

 1.  Section 114 Questionnaire Response from Grumman Corporation
     St. Augustine Operations Facility in St. Augustine, Florida.

 2.  Section 114 Questionnaire Responses from Lockheed Aircraft
     Services Ontario Facility in Ontario, California.

 3.  Section 114 Questionnaire Responses from Naval Aviation
     Depot in Alameda, California.

 4.  Section 114 Questionnaire Response from Warner Robins Air
     Logistics Center, Robins Air Force Base, in Warner Robins,
     Georgia.

 5.  Reference 4.

 6.  Letter.  J. Stafford, Ardrox Inc., to K. Feser, PES.
     February 2, 1993.  Cost of and material safety data sheets
     for paint strippers.

 7.  Telephone Report.  K. Feser, PES, and D. DeHaye, Turco,
     Inc., on December 16, 1992.

 8.  Section 114 Questionnaire Response from American Airlines
     Maintenance and Engineering Center in Tulsa, Oklahoma.

 9.  Reference 2.

10.  Reference 4.

11.  Paint Stripping, Processes developed and used by Delta Air
     Lines, Inc.  Technical Operations Center, Atlanta, Georgia,
     May 19, 1993.

12.  Letter.  D. Collier, Air Transport Association, to V.
     Boothe, EPA:ESD.  June 7, 1993.  Information on commercial
     depainting.

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Ms. Vickie Boothe
August 25, 1993
Page 20
13.  Reference 1.
14.  Reference 3.
15.  Reference 4.
16.  Telephone Report.  K. Feser, PES, and K. Brady, Lockheed
     Aircraft Services Ontario Facility in Ontario, California,
     on February 27, 1993.
17.  Reference 2.
18.  Reference 4.
19.  Reference 4.
20.  Reference 11.
21.  Section 114 Questionnaire Response from Trans World Airlines
     Ground Operations Center in Kansas City, Missouri.
22.  Plant Visit Questionnaire Response from United Airlines
     Maintenance Operation Center in San Francisco, California.
23.  References  21 and 22.
24.  References  21 and 22.
25.  Telephone Report.  D. Hendricks, PES, and G. Mundy, Trans
     World Airlines, on February 11, 1993.
26.  Reference 11.
27.  Telephone Report.  J. Hamilton, PES, and S. Peterson,  United
     Airlines, on March 2, 1993.
28.  Reference 22.
29.  Material safety data sheet  for Turco 6776LO.
30.  Reference 11.
31.  Telephone Report.  K. Feser, PES, and S. Henley,  Delta Air
     Lines,  Inc., on August  11,  1993.
32.  Reference 12.

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Ms. Vickie Boothe
August 25, 1993
Page 21
33.  Section 114 Questionnaire Response from USAir Heavy
     Maintenance Facility in Winston-Salem, North Carolina.

34.  Reference 8.

35.  "Painting Technology Soars at Boeing," Industrial Finishing,
     September 1991, pp. 18-21.

36.  Letter.  R. Warl, USAir, to David Hendricks, PES.  June 4,
     1992.  Information on the percent of aircraft painted.

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                           MEMORANDUM
TO:       Vickie Booths
          US EPA:BSD

FROM:     David Hendricks
          Pacific Environmental Services, Inc. (PES)

DATE:     August 25, 1993
          L:\N019

SUBJECT:  MACT Environmental Analysis for Hand Wipe Cleaning


     The purpose of this memo is to calculate and compare
baseline and MACT environmental impacts for hand wipe cleaning
operations.  Baseline consists of using a cleaning solvent such
as methyl ethyl ketone (vapor pressure 71 mmHg at 20°C).  In
addition, it is assumed that no housekeeping system is utilized
which is focused toward capturing fugitive emissions.  The MACT
floor specifies that hand wipe cleaning solvents are chosen from
an approved list of solvents or comply with a vapor pressure
limit of 45 mmHg at 20°C.  Emission reductions are achieved
through product substitutions such as aqueous and low vapor
pressure cleaners and the implementation of a housekeeping
system.  The housekeeping system includes closed containers for
solvent laden rags and for storage of solvent.  No significant
differences were identified for OEM versus rework or military
versus commercial hand wipe cleaning operations; therefore, the
environmental impacts are differentiated only by model plant
size.

     Table 1 summarizes the baseline and MACT impacts.  With the
implementation of MACT, primary air emissions will be reduced by
54 percent.  The assumptions and calculations used in determining
this impact is detailed below.


BASELINE

Primary Air Emissions

     The baselina for hand wipe cleaning operations has been
defined as usina a cleanina solvent such as methvl ethvl ketone

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Ms. Vickie Boothe
August 25, 1993
Page 2
                             TABLE 1

        ENVIRONMENTAL IMPACTS FOR HAND WIPE CLEANING MACT
Item
1. Baseline HAP Emissions
(Ibs/yr)
2. MACT HAP Emissions
(Ibs/yr)
3. MACT HAP Emission
Reduction
(Ibs/yr)
Model Plants
Small
8,700
4,000
4,700
Medium
232,000
106,720
125,280
Large
1,044,000
480,240
563,760
(vapor pressure 71 mmHg at 20°C) .   In addition, it is assumed
that no housekeeping system is utilized which is focused toward
capturing fugitive emissions.  From Table 6-9 of draft BID
Chapter 6, the average annual HAP emissions from hand wipe
cleaning were calculated to be 58 lb/employee.  The model plants
are sized by number of employees with small, medium, and large
facilities assigned 150, 4,000, and 18,000 employees,
respectively.   For the purposes of the environmental impacts, it
is assumed that the following parameters define baseline:

Baseline HAP Emissions:

Small model plant:  150 emp x 58 Ib/emp =  8,700 Ib/yr

Medium model plant:  4,000 emp x 58 Ib/emp =  232,000 Ib/yr

Large model plant:  18,000 emp x 58 Ib/emp =  1,044,000 Ib/yr
MACT FLOOR

     As stated previously, the MACT floor specifies using
cleaning solvents from an approved list or with a vapor pressure
limit of 45 mmHg at 20"C, and the implementation of a
housekeeping system.  As a result of MACT, air emissions will be
reduced, and wastewater and solid waste generation will not be
affected.

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Ms. Vickie Boothe
August 25, 1993
Page 3
Primary Air Emissions

     California regulations require cleanup solvent housekeeping
measures and a limit on the maximum allowable vapor pressure of
the solvent.  Emissions are 54 percent less per employee than in
other nonattainment areas.1  There are not sufficient data to
determine separate air emission impacts for low vapor pressure
cleaning solvent substitution and housekeeping measures.

MACT Emissions:

Small model plant:  8,700 Ib/yr x  (1-0.54) =  4,000 Ib/yr

Medium model plant:  232,000 Ib/yr x  (1-0.54) =  106,720 Ib/yr

Large model plant:  1,044,000 Ib/yr x  (1-0.54) =  480,240 Ib/yr

Primary air impact is equal to the baseline emissions minus MACT
emissions:

Small model plant:  8,700 Ib/yr - 4,000 Ib/yr  = 4,700 Ib/yr

Medium model plant:  232,000 Ib/yr -  106,720 Ib/yr  = 125,280 Ib/yr

Large model plant:  1,044,000 Ib/yr - 480,240 Ib/yr = 563,760 Ib/yr

Secondary Air Emissions

     Secondary air impacts are generated by the operation of
certain control systems.  For example, incineration may produce
nitrogen oxides (NOX)  and carbon monoxide (CO)  from the
combustion of hydrocarbons.  The MACT floor, however, does not
require control equipment.  Additionally, secondary air impacts
are generated by the use of products that contain different or
additional HAP's from the baseline products.  While the use of
product substitution does not require control equipment, the
substitution may introduce new VOC's  or HAP's into the process.
Since the number of different reformulations is virtually
unlimited, it was impossible to determine what new HAP's or
VOC's, if any, might be introduced.

Wastewater Generation

     Aerospace representatives have mentioned that many
d-limonene and aqueous cleaners require a water rinse in order to
remove any residue.  No data were readily available to quantify
baseline and MACT wastewater consumption.  However, the amount of
wastewater generated from aerospace hand wipe cleaning operations

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Ms. Vickie Boothe
August 25, 1993
Page 4
is not expected to be significantly increased by these control
measures.

Energy Consumption

     The use of low vapor pressure cleaning solutions may lead
some aerospace facilities to utilize heaters and ovens in order
to increase evaporation rates and to ensure that no solvent
remains in crevices and enclosed spaces.  No data were readily
available to quantify baseline and MACT energy consumption.
However, the amount of energy consumption from aerospace hand
wipe cleaning operations is not expected to be significantly
increased by these control measures.

Solid Waste Generation

     .The solid waste generated during hand wipe cleaning consists
of solvent-laden rags.  Because of the California regulations
requiring cleanup solvent housekeeping measures and a limit on
the maximum allowable vapor pressure of the solvent, usage of
cleanup solvent is 68 percent less per employee than in other
nonattainment areas.2  However,  it is possible that the amount of
solid waste generated from hand wipe cleaning operations may
increase due to a need for more rag wiping.  Under previous
procedures, a worker might use a rag only briefly since the
solvent evaporates very quickly.  Under MACT control measures,
the worker may use many more rags to wipe up the solvent since it
does not evaporate quickly.  Additionally, the worker would then
place the rag in a closed container.  At a later time, the worker
would use a clean rag for another job rather than remove the
dirty rag from the sealed container.  Thus, the amount of dirty
rags generated from the hand wipe cleaning process may increase.
No data were readily available to quantify baseline and MACT rag
waste impact.  Additionally, it was assumed that most aerospace
facilities were already disposing of large quantities of solvent-
laden rags as solid waste.  The amount of solid waste generated
from aerospace hand wipe cleaning operations is not expected to
be significantly increased by these control measures.


References

1.   Section 114 Questionnaire Responses.

2.   Reference 1.

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                            MEMORANDUM
TO:       Vickie Boothe
          US EPA: BSD

FROM:     David Hendricks
          Pacific Environmental Services, Inc.  (PES)

DATE:     August 25, 1993
          L:\N019

SUBJECT:  Environmental Impacts for Spray Gun Cleaning


     The purpose of this memo is to calculate and compare
baseline and MACT environmental impacts for spray gun cleaning.
Baseline consists of a combination of enclosed spray gun cleaners
and hand cleaning.  The MACT floor specifies enclosed spray gun
cleaners, cabinet type gun cleaners, vat cleaning using
unatomized spray, and atomized spray into a waste container
fitted with a capture device designed to capture atomized solvent
emissions.  For the purpose of the impact analysis, it will be
assumed that each facility uses enclosed spray gun cleaners.
There is no difference in implementing MACT for commercial versus
military or OEM versus rework facilities; therefore, the impact
analysis was completed only for different size model plants.

     Table 1 summarizes the environmental impacts.  The
implementation of MACT is expected to result in a 73 percent
reduction in air emissions and in solid waste disposal.  The
assumptions and calculations used in deriving these impacts are
detailed below.

BASELINE

     Baseline consists of a combination of enclosed spray gun
cleaners and hand cleaning.  Table 2 presents the baseline values
for the number of enclosed spray gun cleaners in use and the
usage of spray gun cleaning solvent for each model plant size,
Also included in the table are the values of these parameters
that will be used for the MACT impact analysis.
     Tlic b2.celJ.ne and MACT solvent u^^^es wers clsrivscl from s
facility that reported solvent consumption declined from 25

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Ms. Vickie Boothe
August 25, 1993
Page 2
                             TABLE  1

    ENVIRONMENTAL IMPACTS TO IMPLEMENT SPRAY GUN CLEANING MACT
Item
1. Baseline Primary Air
Emissions (Ibs/yr)
2. MACT Primary Air Emissions
(Ibs/yr)
3 . MACT Implementation
Emission Reduction (Ibs/yr)
4. Baseline Solid Waste
Generation (gal/yr)
5. MACT Solid Waste Generation
(gal/yr)
6. MACT Implementation Solid
Waste Reduction (gal/yr)
Model Plants
Small
590
150
440
4,120
1,020
3,100
Medium
800
220
580
5,590
1,530
4,060
Large
1,020
290
730
7,150
2,040
5,110
                             TABLE  2

                 NUMBER OF ENCLOSED GUN  CLEANERS
                  AND SOLVENT USAGE REPRESENTED
                       BY BASELINE AND MACT
Model Plant
Size
Small
Medium
Large
Number of Enclosed
Gun Cleaners
Baseline
1
2
3
MACT
4
6
8
Solvent Usage
(gal/yr)
Baseline
4,200
5,700
7,300
MACT
1,040
1,560
2,080

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Ms. Vickie Booths
August 25, 1993
Page 3
gallons per week to 5 gallons per week after the installation of
an enclosed spray gun cleaner.

Primary Air Emissions

     Based on information provided by Lockheed Missiles and Space
Company, Sunnyvale, California, approximately 98 percent of the
original solvent usage must be disposed.2  Therefore,
approximately 2 percent is released as air emissions.  Using an
average solvent density of 7 pounds per gallon, baseline
emissions are:

Small model plant:  4,200 gal/yr x 0.02 x 7 Ib/gal = 590 Ib/yr

Medium model plant:  5,700 gal/yr x 0.02 x 7 Ib/gal = 800 Ib/yr

Large model plant:  7,300 gal/yr x 0.02 x 7 Ib/gal = 1,020 Ib/yr

Solid Waste Generation

     Based on the above information, approximately 98 percent of
the original solvent usage must be disposed.

Small model plant:  4,200 gal/yr x 0.98 = 4,120 gal/yr

Medium model plant:  5,700 gal/yr x 0.98 = 5,590 gal/yr

Large model plant:  7,300 gal/yr x 0.98 = 7,150 gal/yr
MACT

     As stated previously, the MACT floor specifies enclosed
spray gun cleaners, cabinet type gun cleaners, vat cleaning using
unatomized spray, and atomized spray into a waste container
fitted with a capture device designed to capture atomized solvent
emissions.  For the purpose of the impact analysis, it will be
assumed that each facility uses enclosed spray gun cleaners.  As
a result of implementing these control measures, air emissions
will be reduced.

Primary Air Emissions

     Based on information discussed in the baseline primary air  •
impact section, approximately 2 percent of the cleaning solvent
is released as air emissions.  Using an average solvent density
of 7 pounds per gallon, MACT emissions are;

-------
Ms. Vickie Boothe
August 25, 1993
Page 4
Small model plant:  1,040 gal/yr x 0.02 x 7 Ib/gal - 150 Ib/yr

Medium model plant:  1,560 gal/yr x 0.02 x 7 Ib/gal = 220 Ib/yr

Large model plant:  2,080 gal/yr x 0.02 x 7 Ib/gal = 290 Ib/yr

The total primary air reduction impact of implementing the MACT
standard is equal to the total baseline primary air impact
emissions minus the total MACT primary air emissions.

Small model plant:    590 Ib/yr - 150 Ib/yr = 440 Ib/yr

Medium model plant:   800 Ib/yr - 220 Ib/yr = 580 Ib/yr

Large model plant:  1,020 Ib/yr - 290 Ib/yr = 730 Ib/yr

Secondary Air Emissions

     Secondary air impacts are generated by the operation of
certain control systems.  For example, incineration may produce
amounts of nitrogen oxides (NOX)  and carbon monoxide (CO)  from
the combustion of hydrocarbons.  Additionally, secondary air
impacts are generated by the use of products that contain
different or additional HAP's from the baseline products.  The
use of enclosed spray gun cleaners does not require additional
control equipment or product substitutions.  Therefore, no
additional secondary air impacts are expected.

Wastevater Generation

     No water impacts are expected since there is no water used
in the spray gun cleaning process, either for baseline or MACT.

Energy Consumption

     While the enclosed gun cleaners consume a small amount of
compressed air to operate the diaphragm pump that sprays the
cleaning solvent, it is assumed that they will have a negligible
effect on the overall compressed air consumption of the model
plants.  Consequently, energy impacts will also be negligible.

Solid Waste Generation

     Similar to the baseline solid waste impact, approximately 98
percent of the original solvent usage must be disposed.

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Ms. Vickie Booths
August 25, 1993
Page 5
Small model plant:  1,040 gal/yr x 0.98 = 1,020 gal/yr

Medium model plant:  1,560 gal/yr x 0.98 = 1,530 gal/yr

Large model plant:  2,080 gal/yr x 0.98 = 2,040 gal/yr

The total solid waste reduction impact of implementing the MACT
standard is equal to the total baseline solid waste disposal
minus the total MACT solid waste disposal.

Small model plant:  4,120 gal/yr - 1,020/yr = 3,100 gal/yr

Medium model plant: 5,590 gal/yr - 1,530/yr = 4,060 gal/yr

Large model plant:  7,150 gal/yr - 2,040/yr = 5,110 gal/yr


References

1.   Trip Report - Naval Aviation Depot in Alameda, California,
     on February 28, 1992.

2.   Letter.  Kurucz, Kraig, Lockheed Missiles and Space Company,
     Inc., to David Hendricks, PES.  May 17, 1993.  Information
     on enclosed gun cleaner alternatives.

-------
                                 MEMORANDUM
TO:          Vickie Boothe
             US EPA:BSD

FROM:      David Hendricks
             Pacific Environmental Services, Inc. (PES)

DATE:      December 30, 1993
             L:\N208

SUBJECT:   MACT Environmental Impact Analysis for Primers and Topcoats
       The purpose of this memo is to calculate and compare baseline and MACT
environmental impacts for low HAP primers and topcoats and for the coating application
equipment for these primers and topcoats. Baseline coatings consist of military and
commercial primers and topcoats as reported in the Section 114 questionnaire responses.
Baseline application methods consist of a mix of conventional, HVLP, and electrostatic
spray guns as reported in the Section 114 questionnaire responses.  The MACT floor
specifies product substitutions to reduce the HAP content of the coatings.  For the purpose
of the impact analysis, it will be assumed that each facility replaces all of their
conventional primers and topcoats with reduced HAP content, higher solids primers and
topcoats rather than controlling emissions through abatement.  The MACT floor also
specifies high transfer efficiency methods for primer and topcoat application (e.g., flow
coat, roll coat, dip coat, electrostatic, or HVLP).  For the purpose of the impact analysis,
it will be assumed that all model plants replace their conventional spray guns used to apply
primers and topcoats with HVLP spray guns. Due to the difference  in coating usage
between commercial and military model plants, the environmental impacts will also be
different.  Consequently,  the impact analysis was completed for commercial and military
model plants as well as for different size model plants.  There is no difference, however,
between OEM and rework facilities.

       Table  1 summarizes the environmental impacts.  The implementation of MACT is
expected to result in approximately 66 percent reduction in HAP emissions  for commercial
model plants and 79 percent for military model plants.  The implementation of MACT is
expected to result in approximately 60 percent reduction in VOC emissions for commercial
model plants and 52 percent for military model plants.  There is a typical variation of less
than 15 percent between the model plant sizes.  In most cases, it is a variation of only 2 to
5 percent.  Due to decreased usage and increase transfer efficiency, solid waste will
decrease an average of 32 percent for commercial model plants and an average of 31
percent for military model plants.  No wastewater or energy impacts  are expected due to

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Ms. Vickie Boothe
December 30, 1993
Page 2
                           TABLE 1
     ENVIRONMENTAL IMPACTS TO IMPLEMENT SPRAY GUN MACT
Item
1. Baseline VOC Emissions
(Ibs/yr)
2. Baseline HAP Emissions
(Ibs/yr)
3. MACT VOC Emissions
(Ibs/yr)
4. MACT VOC Emission
Reduction (Ibs/yr)
5. MACT HAP Emissions
(Ibs/yr)
6. MACT HAP Emission
Reduction (Ibs/yr)
9. MACT Solid Waste
Reduction (percent)
Model Plant Size
Commercial
Small
5,350
1,650
1,660
3,690
430
1,220
47
Medium
21,960
6,790
9,730
12,230
2,480
4,310
25
Large
192,090
59,260
87,840
104,250
22,680
36,580
23
Military
Small
1,260
760
500
760
130
630
46
Medium
5,050
3,080
2,650
2,400
680
2,400
24
Large
44,320
26,890
23,930
20,390
6,360
20,530
22

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  Ms. Vickie Boothe
  December 30, 1993
  Page 3
the implementation of MACT.  The assumptions and calculations used in deriving these
impacts are detailed below.

BASELINE

       As stated above, baseline coatings consist of military and commercial primers and
topcoats and baseline application methods consist of a mix of conventional, HVLP, and
electrostatic spray guns as reported in the Section 114 questionnaire responses.  Utilizing the
usage (Table 2) and composition (Table 3) data, baseline coating emissions were calculated.
The typical composition of aerospace primers and topcoats has been determined from material
safety data sheets provided by aerospace coating manufacturers.1'2'3'4 VOC and HAP
composition is less water and exempt solvents.  This does not affect the calculations since the
baseline coatings used  in these calculations do not contain water or exempt solvents.  Sample
VOC and HAP emission calculations for a small, commercial primer operation are presented
below. The calculations for all other coating categories and model plants were done in a
similar manner.

VOC Emissions = 5.6 Ib VOC/gal x 500 gal/yr = 2,800 Ib VOC/yr.
HAP Emissions = 2.6 Ib HAP/gal x 500 gal/yr =  1,300 Ib HAP/yr.

The baseline emissions are presented in Table 4.

The baseline usage is applied with the baseline coating application equipment breakdown that
is defined as follows:

       Small Model  Plants
             Spray guns   -     30 conventional
                                6 HVLP
                                0 electrostatic

       Medium Model Plants
             Spray guns   -     20 conventional
                                50 HVLP
                                 10 electrostatic

       Large Model Plants
             Spray guns   -     24 conventional
                                80 HVLP
                                20 electrostatic

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     Ms. Vickie Boothe
     December 30, 1993
     Page 4
                                   TABLE 2

                 BASELINE AVERAGE ANNUAL COATING USAGE
                            BY MODEL PLANT SIZEa
Model
Plant
Size
Small
Medium
Large
Commercial Usage
(gal)
Primers
500
2,100
18,000
Topcoats
500
2,000
17,900
Military Usage
(gal)
Primers
170
710
6,100
Topcoats
110
420
3,800
             a Source: Section 114 questionnaire responses.
                                   TABLE 3

                BASELINE PRIMER AND TOPCOAT COMPOSITION3
Coating
Category
Primers
Topcoats
Commercial
VOC Content
(Ib/gal less
water and
exempt
solvents)
5.6
5.1
Solids
Content
(gal solids/
gal)
0.22
0.32
HAP
Content
(Ib/gal less
water)
1.9
1.4
Military
VOC Content
(Ib/gal less
water and
exempt
solvents)
4.4
4.6
Solids
Content
(gal
solids/
gal)
0.29
0.34
HAP
Content
(Ib/gal less
water)
3.1
2.1
a Source: Section 114 questionnaire responses and vendor information.

-------
  Ms. Vickie Soothe
  December 30, 1993
  PageS
                                      TABLE 4
                          ANNUAL BASELINE EMISSIONS
Coating
Category
Primers
Topcoats
Model Plant
Small
Medium
Large
Small
Medium
Large
Commercial
VOC (Ib)
2,800
11,760
100,800
2,550
10,200
91,290
HAP (Ib)
950
3,990
34,200
700
2,800
25,060
Military
VOC (Ib)
750
3,120
26,840
510
1,930
17,480
HAP (Ib)
530
2,200
18,910
230
880
7,980
MACT IMPACTS

      As noted above, the implementation of MACT consists of replacing all conventional
coatings with lower HAP content coatings and replacing all conventional spray guns used to
apply primers and topcoats with HVLP spray guns. The result of these substitutions is
reduced coating usage and increased transfer efficiency. Reduced coating usage results in
reduced overall emissions.  Additionally,  increased transfer efficiency reduces overspray,
which results in reduced solid waste.

Primary Air Emissions

      In order to calculate the reduction in coating usage for each model plant through the
use of HVLP spray guns, the volume of coating applied by conventional guns must first be
calculated.  It will be assumed that the volume of coatings applied with conventional spray
guns is equal to the total volume of coating multiplied by the percent of the total number of
spray guns that are conventional spray guns.

Percent conventional spray  guns:

Small model plants: (30 conventional guns/36  total guns) =  83 %

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  Ms. Vickie Boothe
  December 30, 1993
  Page 6
Medium model plants: (20 conventional guns/80 total guns) =25%

Large model plants: (24 conventional guns/124 total guns) =  19%

       The volume of coatings applied conventionally is then the value listed in Table 2
multiplied by the percentage of conventional guns listed for the model plant above.  The
volume applied with conventional guns is presented in Table 5.

       One facility with extensive experience with HVLP spray guns has reported a 45
percent reduction in coating usage when they switched from conventional spray guns to
HVLP spray guns.   Using the 45 percent reduction in coating usage achieved with the
conversion to HVLP spray guns, the reduction in  coating usage is then the volume applied
conventionally (Table 5) multiplied  by 0.45.  These values are presented in Table 6. The
annual coating usage that results after the implementation of HVLP spray guns is the baseline
coating usage (Table 2) minus the usage reduction (Table 6).  These values are presented in
Table 7.

       As mentioned previously, emission reductions are also  achieved through product
substitution.  The composition of MACT floor coatings is typically lower in HAP and VOC
content and higher in solids content than the baseline coatings. MACT  floor VOC and HAP
composition data are given in Table 8. VOC and HAP composition is less water and exempt
solvents.  This does not affect the calculations since the MACT coatings used in these
calculations are higher solids coatings and do not contain water or exempt solvents.
Additionally, since the solids content is higher for MACT floor coatings, the usage is
slightly lower than baseline. Usage is determined on an equivalent solids basis with baseline
usage or,  in this case, the usage that takes into account the reduction for the high transfer
efficiency application equipment. An example calculation is below:

Baseline commercial primer
 Usage after MACT HVLP implementation:  310  gal coating
 Solids content: 0.22 gal solids/gal coating

MACT commercial primer:
 Equivalent usage = baseline usage x baseline solids/MACT solids:

310 gal base coat x 0.22 gal base solids/gal coat = 270 gal coating
              0.25 gal MACT solids/gal coat

The MACT annual coating  usage achieved with the implementation of HVLP spray guns and
product substitutions is presented in Tabie 9.

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Ms. Vickie Boothe
December 30, 1993
Page?
                          TABLE 5

         AVERAGE ANNUAL COATING USAGE APPLIED WITH
        CONVENTIONAL SPRAY GUNS BY MODEL PLANT SIZE
Model
Plant
Size
Small
Medium
Large
Commercial Usage
(gal)
Primers
415
525
3,420
Topcoats
415
500
3,400
Military Usage (gal)
Primers
140
180
1,160
Topcoats
90
110
720
                          TABLE 6

   AVERAGE ANNUAL COATING USAGE REDUCTION ACHIEVED WITH
             HVLP SPRAY GUNS BY MODEL PLANT SIZE
Model
Plant
Size
Small
Medium
Large
Commercial Usage
(gal)
Primers
190
240
1,540
Topcoats
190
230
1,530
Military Usage (gal)
Primers
60
80
520
Topcoats
40
50
320

-------
Ms. Vickie Boothe
December 30, 1993
PageS
                            TABLE?

             MACT AVERAGE ANNUAL COATING USAGE
           (AFTER IMPLEMENTATION OF HVLP SPRAY GUNS)
                      BY MODEL PLANT SIZE
Model Plant
Size
Small
Medium
Large
Commercial Usage
(gal)
Primers
310
1,860
16,460
Topcoats
310
1,770
16,370
Military Usage (gal)
Primers
110
630
5,580
Topcoats
70
370
3,480
                            TABLE 8

          WEIGHTED AVERAGE VOC AND HAP CONTENT FOR
            PRIMERS AND TOPCOATS FOR MACT FLOORS3
Coating
Category

Primers
Topcoats
Commercial
VOC
Content
(Ib/gal less
water and
exempt
solvents)
2.9
3.5
Solids Content
(gal solids/
gal)

0.25
0.4
HAP
Content
(Ib/gal less
water)

0.3
1.4
Military
VOC
Content
(Ib/gal less
water and
exempt
solvents)
2.9
3.5
Solids Content
(gal solids/
gal)

0.3
0.5
HAP
Content
(Ib/gal less
water)

0.3
2.0
  aSource: Section 114 questionnaire responses and vendor information.

-------
  Ms. Vickie Boothe
  December 30, 1993
  Page 9
                                    TABLE 9

                  MACT AVERAGE ANNUAL COATING USAGE
               (AFTER IMPLEMENTATION OF HVLP SPRAY GUNS
                        AND PRODUCT SUBSTITUTIONS)
                             BY MODEL PLANT SIZE
Model
Plant
Size
Small
Medium
Large
Commercial Usage
(gal)
Primers
270
1,640
14,480
Topcoats
250
1,420
13,100
Military Usage (gal)
Primers
110
610
5,390
Topcoats
50
250
2,370
      The resulting MACT emissions were calculated by multiplying the MACT floor VOC
and HAP content averages from Table 3 by the usage amounts in Table 9. The quantity of
data for the HAP content of commercial primers was insufficient to ascertain a reasonable
HAP content.  Therefore, the HAP content for military primers was used for the emission
calculations of commercial primers.  MACT floor VOC and HAP emissions are given in
Table 10. The emission reductions are determined by subtracting the emissions that would
have occurred under the MACT floor from the emissions that will result from the baseline.
The primary air impacts for MACT floor are shown in Table 11.

Secondary Air Emissions

      Secondary air impacts are generated by the operation of certain control systems. For
example, incineration may produce nitrogen oxides (NOX) and carbon monoxide (CO) from
the combustion of hydrocarbons. Additionally, secondary air impacts are generated by the
use of products that contain different or additional HAP's from the baseline products.  The
use of HVLP spray guns does not require either control equipment or coating substitutions.
While the use of low VOC and HAP coating substitutions does not require control
equipment, the substitutions may introduce new VOC's or HAP's into the process.  Since the
number of different reformulations is virtually unlimited,  it was impossible to determine what
new HAP's or VOC's,  if any, might be introduced.  However, the quantity of HAP and
VOC emission will not  exceed the calculated impacts. Therefore, no secondary air impacts
are expected.

-------
Ms. Vickie Boothe
December 30, 1993
Page 10

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  Ms. Vickie Boothe
  December 30, 1993
  Page 11
Wastewater Generation

       Some aerospace coatings that may be used to achieve MACT are waterborne or water-
reducible. This may lead to a minor increase in water usage but should not affect wastewater
quantities.  Additionally, the use of high efficiency application methods does not require the
use of water.  Therefore, no water impacts are expected due to the replacement of
conventional coatings.

Energy Consumption

       Energy usage in the coating application process is generated by the spray gun and
booth equipment; heating, ventilation, and air conditioning; and lighting.  Product
substitution is not expected to have any effect on these systems.  Additionally, HVLP  spray
guns use approximately the same amount of energy to spray coatings as conventional spray
guns. Therefore, no energy impacts are expected due to the replacement of conventional
coatings.

Solid Waste Generation

       The majority of solid waste from primer and topcoat coating application operations is
generated by paint overspray collected in water wash or dry filter systems, and on the floor
and walls of spray booths.  Spray booth cleanup waste, water wash sludge, and spent dry
filters are typical examples of solid  waste from these operations.   Replacing conventional
coatings with reduced HAP and VOC content and higher solids content coatings should
reduce the gallons of coating used and, therefore, the overspray.   Additionally, using high
transfer efficiency application methods also reduces overspray. Using the usage values from
Tables 2 and 9, the percent reductions in usage are listed in Table 12.  This reduction in
coating usage is estimated to be equivalent to the reduction in solid waste generated.

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Ms. Vickie Boothe
December 30, 1993
Page 12
                           TABLE 10
                    ANNUAL MACT EMISSIONS
Coating
Category
Primers
Topcoats
Model
Plant
Small
Medium
Large
Small
Medium
Large
Commercial
VOC (Ib)
780
4,760
41,990
880
4,970
45,850
HAP (Ib)
80
490
4,340
350
1,990
18,340
Military
VOC (Ib)
320
1,770
15,630
180
880
8,300
HAP (Ib)
30
180
1,620
100
500
4,740
                           TABLE 11
               ANNUAL MACT EMISSION REDUCTION
Coating
Category
Primers
Topcoats
Model
Plant
Small
Medium
Large
Small
Medium
Large
Commercial
VOC (Ib)
2,020
7,000
58,810
1,670
5,230
45,440
HAP (Ib)
870
3,500
29,860
350
810
6,720
Military
VOC (Ib)
430
1,350
11,210
330
1,050
9,180
HAP (Ib)
500
2,020
17,290
130
380
3,240

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  Ms. Vickie Boothe
  December 30, 1993
  Page 13
                                    TABLE 12

      ANNUAL MACT FLOOR REDUCTIONS IN COATING USAGE (PERCENT)
Model Plant
Small
Medium
Large
Commercial
47
25
23
Military
46
24
22
References

1.     Letter. K. McKown, Akzo, to D. Hendricks, PES.  February 1993.  Coating
      composition data and material safety data sheets.

2.     Letter. F. Schuster, Crown Metro, to J. Hamilton, PES.  March 17, 1993.  Coating
      composition data and material safety data sheets.

3.     Letter. S. Smith, DEFT, to J. Hamilton, PES.  March 11, 1993.  Coating
      composition data and material safety data sheets.

4.     Letter. R. Martin, Courtaulds Aerospace, to K. Feser, PES.  February 22, 1993.
      Coating composition data and material safety data sheets.
5.     Section 114 Questionnaire Response from Naval Aviation Depot in Alameda,
      California.

-------

-------
                                 MEMORANDUM
TO:          Vickie Boothe
             US EPA:ESD

FROM:      David Hendricks
             Pacific Environmental Services, Inc.

DATE:      February 15, 1994
             L:\N208

SUBJECT:   Nationwide Environmental Impacts for the Control of Primer and Topcoat
             Inorganic Emissions, Depainting Inorganic Emissions, Wastewater
             Emissions, Storage Tank Emissions, and Waste Emissions
       The purpose of this memo is to calculate and compare baseline and MACT
environmental impacts for the control of primer and topcoat inorganic emissions,
depainting inorganic emissions, wastewater emissions, storage tank emissions, and waste
emissions.  There is no difference in implementing  MACT for commercial versus military
or OEM versus rework facilities; therefore, the impact analyses were completed only for
different size model plants.  Additionally, due to the available data, the impacts were
calculated on a nationwide basis.

       For the purpose of the primer and topcoat inorganic emissions impact analysis, it
was assumed that 5 percent of small facilities do not perform primer and topcoat operations
within a booth or hangar, and that all medium and large facilities perform all of these
operations within a booth or hangar.  Additionally,  10 percent of small, 2 percent of
medium, and 1 percent of large facilities perform primer and topcoat operations within a
booth or hangar with no dry filters or waterwash.  The MACT floor level of control
specifies that all primer and topcoat operations must be performed within a spray booth or
hangar with an active ventilation system.  The exhaust air stream must pass through either
dry filters or a waterwash system.

       For the purpose of the depainting inorganic emissions impact analysis, it was
assumed that only 5 percent of small and medium rework facilities and all large rework
facilities depaint the outer surface of aerospace vehicles.  The impact analysis is based on
the conversion from low efficiency paniculate filters to high efficiency particulate filters
that meet the MACT floor level of control.  The MACT floor level of control specifies that
inorganic HAP emissions be controlled by 99 percent.  This can be achieved by through
the use of particulate filters or baghouses to control particulate emissions.

-------
Ms. Vickie Boothe
February 15, 1994
Page 2


       MACT floor is no control for wastewater and storage tanks; therefore, no impacts
will be incurred.  Additionally,  100 percent of die reporting facilities are performing
housekeeping measures for waste; therefore, no impacts will be incurred.

       Tables  1 and 2 summarize the environmental impacts for coating application and
depainting inorganic emission controls.  The implementation of MACT for coating
application is expected to result in approximately 57 percent reduction in inorganic air
emissions for small model plants, 16 percent for medium model plants, and 25 percent for
large model plants.  The energy impact is a 5  percent increase for small model plants only.
The implementation is also expected to result in approximately  18 percent increase in solid
waste for small model plants, 2 percent for medium model plants, and 6 percent for large
model plants.  The implementation of MACT  for depainting is expected to result in a 80
percent reduction in air emissions.  The assumptions and calculations used in deriving  these
impacts are detailed below.

A.  PRIMER AND TOPCOAT INORGANIC HAP EMISSIONS

Baseline

       For the purpose of the impact analysis, it was assumed that 5 percent of small
facilities  do not perform primer and topcoat operations within a booth or hangar, and that
all medium and large facilities perform all of these operations within a booth or hangar.
Additionally, 10 percent of small, 2 percent of medium, and 1 percent of large facilities
perform primer and topcoat operations within  a booth or hangar with no dry filters or
waterwash.  It is further assumed that these booths and hangars already have a ventilation
system in place.  Finally, it is assumed that 4  percent of the facilities using filters are using
high efficiency dry filters and 2 percent are using high efficiency waterwash booths.

       Table 3 presents the total number of facilities nationwide by size, number of each
size of facility currently not painting within a  booth or hangar,  number of facilities
currently painting within a booth or hangar with no dry filters or waterwash, and number
of facilities using filters.

-------
Ms. Vickie Boothe
February 15, 1994
PageS
                            TABLE 1
   NATIONWIDE ENVIRONMENTAL IMPACTS TO IMPLEMENT PRIMER AND
               TOPCOAT INORGANIC EMISSIONS MACT
Item
1. Baseline Primary Air Emissions
db/yr)
2. MACT Primary Air Emissions
Ob/yr)
3. MACT Implementation Emission
Reduction (Ib/yr)
4. Baseline Energy Consumption
(kWatt-hr/yr)
5. MACT Energy Consumption
(kWatt-hr/yr)
6. MACT Implementation Energy
Increase (kWatt-hr/yr)
7. Baseline Solid Waste Generation
Ob/yr)
8. MACT Solid Waste Generation
db/yr)
9. MACT Implementation Solid
Waste Increase (Ib/yr)
Nationwide Model Plants
Small
140
60
80
117,360,000
123,300,000
5,940,000
7,089,120
8,372,160
1,283,040
Medium
310
260
50
NA
NA
NA
54,509,370
55,658,110
1,148,740
Large
40
30
10
NA
NA
NA
942,340
1,001,230
58,890

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Ms. Vickie Boothe
February 15, 1994
Page 4
                            TABLE 2

   NATIONWIDE ENVIRONMENTAL IMPACTS TO IMPLEMENT DEPAINTING
                    INORGANIC EMISSIONS MACT
Item
1. Baseline Primary Air Emissions
(Ibs/yr)
2. MACT Primary Air Emissions (Ibs/yr)
3. MACT Implementation Emission
Reduction (Ibs/yr)
Nationwide Model Plants
Small
156,600
31,320
125,280
Medium
583,270
116,800
466,470
Large
216,700
43,350
173,350

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Ms. Vickie Boothe
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Page 6
Baseline Primary Air Emissions

       Table 4 presents typical coating usage by model plant.

                                        Table 4

                                Typical Coating Usage*
Model Plant Size
Small
Medium
Large
Primer
500
2,000
18,000
Topcoat
500
2,000
18,000
Total
1,000
4,000
36,000
              'Source: Section 114 questionnaire responses.

       Approximately 0.01 percent of the typical primer or topcoat is inorganic HAP.'-2-3-4
Using an average coating density of 9 pounds per gallon5, baseline inorganic emissions
from primer and topcoat applications are:

Small model plant:  1,000 gal/yr x 0.0001 x 9 Ib/gal = 0.9 Ib/yr

Medium model plant:  4,000 gal/yr x 0.0001  x 9 Ib/gal = 3.6 Ib/yr

Large model plant:  36,000 gal/yr x 0.0001 x 9 Ib/gal  = 32.4 Ib/yr

Assuming that, when a coating is sprayed, 40 percent of the paint particles are transferred
to the substrate, 10 percent fall out of the airstream on to the booth walls or floor, and 50
percent of the particulates reach the filters, baseline emissions to the filters are:

Small model plant:  0.9 Ib/yr x 0.50 = 0.45  Ib/yr

Medium model plant:  3.6 Ib/yr x 0.50 = 1.8 Ib/yr

Large model plant:  32.4 Ib/yr x 0.50 =  16.2 Ib/yr

The control efficiency of a low efficiency filter is estimated at  90 percent.  The control
efficiency of a high efficiency dry filter is 99.89 percent as stated in the Section 114
data.6-7-8  Also stated in the Section  114 data, the control efficiency of a high efficiency
waterwash booth is 95.67 percent.9-10-"  Using the appropriate control efficiency and the

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Ms. Vickie Boothe
February 15, 1994
Page?


above emission rates by model plant, baseline emissions of inorganic HAPs from coating
application are listed in Table 5.  Nationwide baseline emissions of inorganic HAPs are
listed in Table 6 and equal the numbers in Table 5 multiplied by the numbers in Table 3.
Example calculations are:

Small model plant (with low efficiency dry filters):  0.45  Ib/yr x (1-0.90)  = 0.045 Ib/yr

Nationwide small model plant (with low efficiency dry filters):
                    0.045 Ib/yr per facility x 1041 facilities  = 47 Ib/yr

Baseline Energy Consumption

       Based on vendor data, a 5 horsepower motor is used to run the ventilation system
of all paint booths.12 From this same vendor data, the pump used in a waterwash booth is
approximately 10 horsepower.13  Spray booths are used approximately 2 shifts or 16 hours
per day, 250 days per  year.  Therefore,  the nationwide  energy usage by  model plant is:

Small Facilities

       (6 booths/facility x 5 hp/booth x  0.75 kWatt/hp  x  16 hour/day x 250 days/yr x
       1,252 facilities) + (6 booths/facility x 10 hp/booth x 0.75 kWatt/hp x
          16 hour/day x 250 days/yr x 26 facilities) =  117,360,000 kWatt-hr/yr

The energy usage  of ventilation systems  and pumps for  medium and large  facilities will not
be taken into account in this calculation  since the energy usage will not change from the
baseline to MACT.

Baseline Solid Waste Generation

       For a worst case estimate, it is assumed that all the low efficiency filter systems are
dry filter systems.  The total number of model plants using  dry filters equals the facilities
using low efficiency filters and the facilities using high  efficiency dry filters.

Small model plant:  1,041 facilities + 53 facilities = 1,094 facilities

Medium model plant:  1,410 facilities + 61 facilities = 1,471 facilities

Large model plant:  15 facilities  4-  1 facility =16 facilities

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Ms. Vickie Boothe
February  15, 1994
Page 9


From the  cost impact memo14,  it is assumed that dry filters are changed 4 times a year.
From vendor data15, each dry filter weighs approximately 4 pounds.  Baseline solid waste
generation is calculated as shown below using the above assumptions and data from the
cost memo.

Small Facilities

       10' x 10' Booth
       36 filters/boom x 5 boodis/facility x 4 Ib/filter x 4 changes/yr
       x 1,094 facilities = 3,150,720 Ib/yr

       25' x 25' Booth
       225 filters/booth x 1 booth/facility x 4 Ib/filter x 4 changes/yr
       x 1,094 facilities = 3,938,400 Ib/yr

       Total nationwide solid waste = 7,089,120 Ib/yr

Medium Facilities

       10' x 10' Booth
       36 filters/booth x 7 booths/facility x 4 Ib/filter x 4 changes/yr
       x 1,471 facilities = 5,931,070 Ib/yr

       25' x 25' Booth
       225 filters/booth x 2 booths/facility  x 4  Ib/filter x 4 changes/yr
       x 1,471 facilities = 10,591,200 Ib/yr

       150' x 200' x 75' Hangar
       807 filters/hangar x 2 hangars/facility  x  4 Ib/facility x  4 changes/yr
       x 1,471 facilities = 37,987,100 Ib/yr

       Total nationwide solid waste = 54,509,370 Ib/yr

Large Facilities

       10' x 10' Booth
       36 filters/booth x  10 booths/facility  x 4  Ib/filter x 4 changes/yr
       x 16 facilities = 92,160 Ib/yr

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Ms. Vickie Boothe
February 15, 1994
Page 10
       25'  x 25' Booth
       225 filters/booth x 4 booths/facility x 4 Ib/filter x 4 changes/yr
       x 16 facilities  = 230,400 Ib/yr

       150' x 200'  x  75' Hangar
       807 filters/hangar x 3 hangars/facility x 4 Ib/filter x 4 changes/yr
       x 16 facilities  = 619,780 Ib/yr

       Total nationwide solid waste = 942,340 Ib/yr

MACT Floor

       The MACT floor level of control specifies that all primer and topcoat operations
must be performed within a spray  booth or hangar with an active ventilation system. The
exhaust air stream must pass through either dry filters or a waterwash system.  The impact
analysis assumes that  facilities that do not currently paint within a booth or hangar and
facilities that paint within a booth  or hangar but have no dry filters or waterwash will begin
filtering their exhaust air stream through a low efficiency dry filter system.

       Table 7 presents the total number of facilities nationwide by size and the  number of
each size of facility currently painting within a booth or hangar with dry filters or
waterwash.

Primary Air Emissions

       As  stated in the baseline section, the control efficiency of a low efficiency filter is
estimated at 90 percent, the control efficiency of a high efficiency dry filter is 99.89
percent, and the control efficiency of a high efficiency waterwash booth is 95.67 percent.
Using these control efficiencies and the emission estimates calculated in the baseline
section, MACT emissions of inorganic  HAPs from coating application are listed in Table 8
and equal the baseline emission estimates multiplied by the appropriate  control efficiency.
Table  9 contains the nationwide emissions and these values are the values in Table 7
multiplied  by  the values in Table 8.  Example calculations are:

Small  model plant (with low efficiency dry filters):  0.45 Ib/yr x (1-0.90) = 0.045 Ib/yr

Nationwide small model plant (with low efficiency dry filters):
                     0.045 Ib/yr per facility x 1,239 facilities  = 56 Ib/yr

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Ms. Vickie Boothe
February 15, 1994
Page 11
                                  TABLE?
                  MACT Nationwide Distribution of Model Plants
Facility
Size




Small
Medium
Large
Total Number
of
Facilities



1,318
1,533
18
Number of
Facilities with
Low Efficiency
Filters


1,239
1,441
16
Number of
Facilities with
High
Efficiency Dry
Filters

53
61
1
Number of
Facilities with
High
Efficiency
Waterwash
Booths
26
31
1
                                  TABLES

                MACT Inorganic Emissions from Coating Operations
                                by Model Plant
Facility
Size





Small
Medium
Large
Emissions
from Facilities
with Low
Efficiency
Filters
db/yr)

0.045
0.18
1.62
Emissions
from Facilities
with High
Efficiency Dry
Filters
db/yr)

0.0005
0.002
0.02
Emissions
from Facilities
with High
Efficiency
Waterwash
Booths
db/yr)
0.019
0.078
0.78

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Ms. Vickie Boothe
February 15, 1994
Page 12
                                   TABLE 9

           MACT Nationwide Inorganic Emissions from Coating Operations
                                 by Model Plant
Facility
Size






Small
Medium
Large
Nationwide
Emissions
from Facilities
with Low
Efficiency
Filters
Ob/yr)

56
259
26
Nationwide
Emissions
from Facilities
with High
Efficiency Dry
Filters
(Ib/yr)

0.03
0.12
0.02
Nationwide
Emissions
from Facilities
with High
Efficiency
Waterwash
Booths
(Ib/yr)
0.49
2.4
0.78
Total







60
260
30

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Ms. Vickie Boothe
February 15, 1994
Page 13


The total primary air reduction impact of implementing the MACT standard is equal to the
total baseline primary air impact emissions minus the total MACT primary air emissions.

Small model plant:  140 Ib/yr - 60 Ib/yr = 80 Ib/yr

Medium model plant: 310 Ib/yr - 260 Ib/yr = 50 Ib/yr

Large model plant:  40 Ib/yr - 30 Ib/yr = 10 Ib/yr

Secondary Air Emissions

       Secondary air impacts are generated by the operation of certain control systems.
For example, incineration may produce amounts of nitrogen oxides (NOJ and carbon
monoxide (CO) from the combustion of hydrocarbons.  Additionally,  secondary air impacts
are generated by the use of products that contain different or additional HAP's from the
baseline products.  The use of either paniculate filters or waterwash booths does not
require additional control equipment or product substitutions.  Therefore, no additional
secondary air impacts are expected.

Waste-water Generation

       There is no water used with dry filters.  Additionally, current practice with
waterwash booths is to recycle the water in the booth replacing only the water lost through
evaporation and sludge removal. This water usage is expected to be insignificant when
compared to the model plant as a whole.  Therefore, it is expected that the overall effect of
increased water usage is negligible and no water impacts are expected.

Energy Consumption

       Only 5 percent of small model plants and none of the medium  or large plants will
have to move their painting operations from outside into a spray booth.  These facilities
will need to install fans, motors, and pumps for their new booths. Similar to baseline
calculations, it is assumed that a 5 horsepower fan and motor is used for the ventilation
system of all paint booths.  Additionally,  the pump used in a waterwash booth is
approximately 10 horsepower.  Spray booths are used approximately 2 shifts or 16 hours
per day, 250 days per year.  Nationwide MACT energy usage by model plant is:

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Ms. Vickie Boothe
February 15, 1994
Page 14


Small Facilities

       (6 booths/facility x 5 hp/booth x 0.75 kWatt/hp x 16 hour/day x 250 days/yr x
       1,318 facilities)  + (6 booths/facility x 10 hp/booth x 0.75 kWatt/hp x 16 hour/day
       x 250 days/yr x  26 facilities) =  123,300,000 kWatt-hr/yr

The energy usage of the ventilation systems and pumps for medium and large facilities will
not be taken into account  in this calculation since the energy usage will not change from
the baseline to MACT.

The total nationwide energy impact of implementing the MACT standard is equal to the
total MACT energy consumption minus the total baseline energy consumption.

Small model plant:  123,300,000 kWatt-hr/yr - 117,360,000 kWatt-hr/yr
                                                =  5,940,000 kWatt-hr/yr

Solid Waste Generation

       For worst case estimates, it is assumed that all the low efficiency filter systems are
dry filter systems. The total number of model plants using dry filters equals the facilities
using low efficiency filters and the facilities using high efficiency dry filters.

Small model plant:  1,239 facilities + 53 facilities = 1,292 facilities

Medium model plant:  1,441 facilities + 61 facilities = 1,502 facilities

Large model plant:  16  facilities + 1 facility =17 facilities

Similar to baseline calculations, it is assumed that dry filters are changed 4 times a year.
No data is available on  the weight of each dry filter.  Therefore, from facility visits, it is
assumed that each dry filter weighs approximately 4  pounds.   Solid waste impacts are
calculated using the above assumptions and data from the cost memo.

Small Facilities

       10' x  10' Booth
       36 filters/booth x 5 booths/facility x 4 Ib/filter x 4 changes/yr
       x 1,292 facilities = 3,720,960 Ib/yr

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Ms. Vickie Boothe
February 15, 1994
Page 15


       25' x 25' Booth
       225 filters/booth x 1 booth/facility x 4 Ib/filter x 4 changes/yr
       x 1,292 facilities = 4,651,200 Ib/yr

       Total nationwide solid waste = 8,372,160 Ib/yr

Medium Facilities

       10' x 10' Booth
       36 filters/booth x 7 booths/facility x 4 Ib/filter x 4 changes/yr
       x 1,502 facilities = 6,056,060 Ib/yr

       25' x 25' Booth
       225 filters/booth x 2 booths/facility x 4 Ib/filter x 4 changes/yr
       x 1,502 facilities = 10,814,400 Ib/yr

       150' x 200' x 75' Hangar
       807 filters/hangar x 2 hangars/facility x 4 Ib/facility x 4 changes/yr
       x 1,502 facilities = 38,787,650 Ib/yr

       Total nationwide solid waste = 55,658,110 Ib/yr

Large  Facilities

       10' x 10' Booth
       36 filters/booth x 10 booths/facility x 4 Ib/filter x 4 changes/yr
       x 17 facilities = 97,920 Ib/yr

       25' x25' Booth
       225 filters/booth x 4 booths/facility x 4 Ib/filter x 4 changes/yr
       x 17 facilities = 244,800 Ib/yr

       150' x 200' x 75' Hangar
       807 filters/hangar x 3 hangars/facility x 4 Ib/filter x 4 changes/yr
       x 17 facilities = 658,510 Ib/yr

       Total nationwide solid waste = 1,001,230 Ib/yr

The total nationwide solid waste impact of implementing the MACT standard is equal to
the total MACT solid waste minus the total baseline solid waste.

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Ms. Vickie Boothe
February 15, 1994
Page 16
Small model plant:  8,372,160 Ib/yr - 7,089,120 Ib/yr = 1,283,040 Ib/yr

Medium model plant:  55,658,110 Ib/yr - 54,509,370 Ib/yr = 1,148,740 Ib/yr

Large model plant:  1,001,230 Ib/yr - 942,340 Ib/yr = 58,890 Ib/yr
B.  DEPAINTING INORGANIC HAP EMISSIONS

      The MACT floor level of control specifies that inorganic HAP paniculate emissions
be controlled by 99 percent. This can be achieved through the use of paniculate filters
such as panel filters or baghouses.  This analysis examines the conversion from low
efficiency paniculate filters to high efficiency paniculate filters that meet the MACT floor
level of control.

      It is not reasonable to assume that all commercial and military rework facilities (a
total of 2,026 facilities) depaint the outer surface of aerospace vehicles. Therefore, it was
assumed that only 5 percent of the small and medium facilities and all of the large facilities
perform outer surface depainting (see Table 10).

                                     TABLE 10
         NUMBER OF DEPAINTING FACILITIES BY MODEL PLANT SIZE
Model Plant Size
Small
Medium
Large
Number of Facilities
27
73
5
Baseline

       Baseline has been defined as depainting fully painted aircraft with plastic media
blasting and using paniculate filters with a control efficiency of 95 percent.  Many military
facilities are currently using plastic media blasting.  Therefore, for the purpose of this
option, data from military facilities will be used for both baseline and MACT.

       From vendor information, approximately 50 percent of the blasting particulates fall
to the ground and 50 percent are airborne.16 The emission factor for plastic media blasting
is 0.021 pounds of emissions per pound of media used.17 Based on data from a medium,

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Ms. Vickie Boothe
February 15, 1994
Page 17


military rework facility, a typical flow rate of media during blasting is 2,700 pounds per
hour.18 Using the above data, uncontrolled PM10 emissions are:

Average = 2,700 Ib media/hr x 0.5 x 0.021 Ib emissions/lb media = 28 Ib emissions/hr

A medium, military rework facility also stated that it takes 0.03 hours to strip 1 square foot
of aircraft outer surface area.19 From the environmental impacts memo for depainting, the
total outer surface area of aircraft reworked annually for each military model plant is20:

Small model plant:  137,900 ftVyr

Medium model plant:  190,500 ftVyr

Large model plant:   1,032,000 ftVyr

The time it takes to strip this area by model plant is calculated using the 0.03 hr/ft2
stripping rate. The total  time for depainting by model plant is:

Small model plant:  137,900 ftVyr x 0.03 hr/ft2 = 4,140 hr/yr

Medium model plant:  190,500 ftVyr x 0.03 hr/ft2 = 5,710 hr/yr

Large model plant:   1,032,000 ftVyr x 0.03 hr/ft2 = 30,960 hr/yr

Using the emission rate of 28 Ib/hr for each of the model plants, uncontrolled emissions
are:

Small model plant:  4,140 hr/yr  x 28 Ib/hr = 115,920 Ib/yr

Medium model plant:  5,710 hr/yr x 28 Ib/hr = 159,880 Ib/yr

Large model plant:  30,960 hr/yr x  28 Ib/hr =  866,880 Ib/yr

Baseline emissions per model plant,  using a control efficiency of 95 percent, are:

Small model plant:  (115,920 Ib/yr x (1 - 0.95) = 5,800  Ib/yr

Medium model plant:  (159,880  Ib/yr x (1 - 0.95) = 7,990 ib/yr

Large model plant:  (866,880 Ib/yr x (1 - 0.95) = 43,340 Ib/yr

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Ms. Vickie Boothe
February 15, 1994
Page 18
Using the number of facilities that perform depainting operations as listed in Table 10,
nationwide baseline emission are:

Small model plant:  5,800 Ib/yr x 27 rework facilities = 156,600 Ib/yr

Medium model plant: 7,990 Ib/yr x 73 rework facilities = 583,270 Ib/yr

Large model plant:  43,340 Ib/yr x 5 rework facilities = 216,700 Ib/yr

MACT Floor

      The MACT floor can be achieved by installing particulate filters with a minimum
control efficiency of 99 percent.  For the purpose of the impact analysis, it was assumed
that each facility performs the blasting operation within  a hangar and that a ventilation
system is in place.

Primary Air Emissions

Assuming that MACT floor has a minimum control efficiency of 99 percent, MACT
emissions by model plant are:

Small model plant:  115,920 Ib/yr x (1 - 0.99) =  1,160 Ib/yr

Medium model plant: 159,880 Ib/yr x  (1 - 0.99) =  1,600 Ib/yr

Large model plant:  866,880 Ib/yr x (1 - 0.99) =  8,670 Ib/yr

Again using the number of depainting  facilities from Table 10, nationwide MACT emission
are:

Small model plant:  1,160 Ib/yr x 27 rework facilities = 31,320 Ib/yr

Medium model plant: 1,600 Ib/yr x 73 rework facilities = 116,800 Ib/yr

Large model plant:  8,670 Ib/yr x 5 rework facilities =  43,350 Ib/yr

The total nationwide primary air impact of implementing the MACT standard is equal to
the total nationwide baseline primary air impact emissions minus the total nationwide
MACT primary air emissions.

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Ms. Vickie Boothe
February 15, 1994
Page 19


Small model plant:   156,600 Ib/yr - 31,320 Ib/yr =  125,280 Ib/yr

Medium model plant: 583,270 Ib/yr - 116,800 Ib/yr = 466,470 Ib/yr

Large model plant:  216,700 Ib/yr - 43,350 Ib/yr = 173,350 Ib/yr

Secondary Air Emissions

       Secondary air impacts are generated by the operation of certain control systems.
For example, incineration may produce amounts of nitrogen oxides (NOJ and carbon
monoxide (CO) from the combustion of hydrocarbons.  Additionally, secondary air impacts
are generated by the use of products that contain different or additional HAP's from the
baseline products.  The use of paniculate filters does not require incineration or product
substitutions. Therefore, no additional  secondary air impacts are expected.

Wastewater Generation

       No water impacts are expected since there is no water used in conjunction with
paniculate filters, either for baseline or MACT.
                                         •
Energy Consumption

       While the fans and ventilation systems consume energy to operate, it is assumed that
they will have a negligible effect on the overall energy consumption of the model plants.
Additionally, ventilation systems will not have to change from baseline to MACT.
Consequently, energy impacts will be negligible.

Solid Waste Generation

       The only solid waste generated during this process is the spent paniculate filters. It
is not anticipated that the amount of spent filters generated under the MACT floor level of
control will vary significantly with the baseline level of control.

C.  WASTEWATER

       MACT floor is no control; therefore, no impact incurred.


D. STORAGE TANKS

       MACT floor is no control; therefore, no impact incurred.

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Ms. Vickie Boothe
February 15, 1994
Page 20
E. WASTE

       100 percent of the reporting facilities are performing housekeeping measures;
therefore, no impacts will be incurred.
References

 1.     Letter.  K. McKown, Akzo, to D. Hendricks, PES. February 1993.  Coating
       composition data and material safety data sheets.

 2.     Letter.  F. Schuster, Crown Metro, to J. Hamilton, PES. March 17, 1993.
       Coating composition data and material safety data sheets.

 3.     Letter.  S. Smith, DEFT, to J. Hamilton, PES.  March 11,  1993.  Coating
       composition data and material safety data sheets.

 4.     Letter.  R. Martin,  Courtaulds Aerospace, to K. Feser, PES.  February 22, 1993.
       Coating composition data and material safety data sheets.
                             •
 5.     References 1, 2, 3, and 4.

 6.     Section 114 Questionnaire Response from Lockheed Aircraft Service Company in
       Palmdale, California.

 7.     Section 114 Questionnaire Response from The Boeing  Company in Wichita, Kansas.

 8.     Section 114 Questionnaire Response from Douglas Aircraft Company in Long
       Beach, California.

 9.     Section 114 Questionnaire Response from Naval Aviation Depot in Cherry Point,
       North Carolina.

10.    Section 114 Questionnaire Response from The Boeing  Company in Renton,
       Washington.

11.    Section 114 Questionnaire Response from The Boeing  Company in Auburn,
       Washington.

12.    Industrial Spray Booths.  Catalog SB-12, Selecting a Spray Booth.  Sinks
       Manufacturing Company.  March 1993.  pp. 6-9 -6-11.

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Ms. Vickie Boothe
February 15, 1994
Page 21
13.   Reference 12. pp. 6-22 - 6-25.

14.   Memo.  David Hendricks, PES, to Vickie Boothe, EPA:ESD, Nationwide MACT
      Cost Analysis for the Control of Primer and Topcoat Inorganic Emissions,
      Depainting Inorganic Emissions, Wastewater Emissions, Storage Tank Emissions,
      and Waste Emissions, December 2, 1993.

15.   Letter.  J. Nolan, Puget Sound Air Pollution Control Agency, to V. Boothe,
      EPAiESD. October  15,  1993.  Transmitting information on spray booth filters.

16.   Dry Media Stripping of Aircraft: The Replacement of Toxic Air Contaminant
      Methylene Chloride.  M. Balagopalan.  South Coast Air Quality Management
      District. 28th Annual Aerospace/Airline Plating and Metal Finishing Forum and
      Exposition.  April 22, 1992. p. 3.

17.   Reference 16.

18.   Reference 16.

19.   Section 114 Questionnaire Response from Lockheed Aircraft Services Ontario
      Facility in Ontario, California.

20.   Memo.  David Hendricks, PES, to Vickie Boothe, EPA:BSD, MACT
      Environmental Impact Analysis for Depainting, August 25, 1993.

21.   Section 114 Questionnaire Response from Tinker Air Force Base, Oklahoma.

-------
APPENDIX B.  DEVELOPMENT OF MODEL PLANT COSTS

-------
                           MEMORANDUM
TO:       Vickie Boothe
          US EPAtESD

FROM:     David Hendricks
          Pacific Environmental Services, Inc. (PES)

DATE:     August 25, 1993
          L:\N019

SUBJECT:  Cost Analysis for Chemical Milling Maskant
     The purpose of this memo is to compare baseline and MACT
costs for chemical milling maskants.  Baseline consists of a dip
coating operation using a solvent based maskant.  The MACT floor
specifies an emission rate of 1.3 pounds of HAP's per gallon less
water of maskant as applied, which is based on the use of either
solvent based maskant and a carbon adsorber to control emissions
or the use of waterborne maskants.

     Table 1 summarizes the costs.  As presented on line 3 of
Table 1, the use of a carbon adsorber is expected to result in a
cost of $125,200 per year for medium model plants and $135,540
per year for large model plants.  The use of waterborne maskants
is expected to result in a cost of $106,680 per year for medium
model plants and $199,090 for large model plants, as presented in
line 7 of Table 1.  The assumptions and calculations used in
deriving these costs are detailed below.

     As defined in draft BID Chapter 6, chemical milling maskant
operations occur only in commercial/OEM, military/OEM, and
military/rework medium and large model plants.  Since there is no
difference in implementing MACT floor for commercial versus
military or OEM versus rework facilities, the cost analysis has
been performed only for different size model plants.
BASELINE

     The baseline usage of solvent based maskant was obtained
from the Section 114 cruestionnaire rssconses of -\

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Ms. Vickie Boothe
August 25, 1993
Page 2
                             TABLE 1

     ANNUAL COSTS TO IMPLEMENT CHEMICAL MILLING MASKANT MACT
Item
1. Carbon Adsorber - Annualized
Costs
2. Carbon Adsorber - Annual
Operating Costs
3. Total MACT Implementation
Costs - Carbon Adsorber
(Line 1 + Line 2)
4. Tanks and Ovens - Annualized
Capital Costs
5. Ovens - Annual Costs
6. Maskant Costs
7. Total MACT Implementation
Costs - Waterborne Maskants
(Line 4 + Line 5 + Line 6)
Model Plant
Medium
$54,500
70,700
125,200
31,380
2,700
72,600
$106,680
Large
$58,540
77,000
135,540
35,590
5,900
157,600
$199,090

-------
Ms. Vickie Boothe
August 25, 1993
Page 3
military/OEM/medium facility and a military/OEM/large facility.
The baseline usage is 12,000 gal/yr for a medium facility,  and
26,000 gal/yr for a large facility.2  The dip tank sizes used for
the MACT cost analysis were determined from the tanks observed
during several site visits.

MACT COSTS - CARBON ADSORBER

     Both the baseline and MACT scenarios can be based on the use
of solvent based maskant.  Therefore, the type of maskant, usage,
and dip application equipment remain the same and do not require
costing.  The only factor relevant in the cost analysis is the
carbon adsorber.

Carbon Adsorber Costs

     The exhaust flow rate and HAP concentration in the exhaust
stream  (inlet loading) were taken from the same Section 114
questionnaire responses referenced above for maskant usage.  The
values used for medium model plants were a flow rate of 10,000
acfm and an inlet loading of 120 Ib/hr.  For large model plants,
a flow rate of 20,000 acfm and an inlet loading of 120 Ib/hr were
used.  The OAQPS Control Cost Manual3 was then used to develop
the carbon adsorber capital costs and annual costs presented in
Table 2.

   Annualized  Costs

     The annualized costs were calculated by the following
equation:


                 AnnuaTized  Costs  = TCC
    where,

    TCC  =  Total Capital Cost
    i    =  Interest Rate
    n    =  Equipment Life (years)

Using the total capital costs from  line 4 of Table 2, an  intaresi
rate of 7 percent,  and an equipment life of 10 years, the
annualized costs  by model plant are:

    Medium model plant:  $54,500/yr
    Large  model plant:    $58,540/yr

-------
Ms. Vickie Boothe
August 25, 1993
Page 4
                             TABLE 2

             CAPITAL AND ANNUAL CARBON ADSORBER COSTS

                FOR MEDIUM AND LARGE MODEL PLANTS
Item
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Purchased Equipment, including
taxes and freight
Installation
Indirect
Total Capital Costs (Line 1 +
Line 2 + Line 3)
Operating Labor
Maintenance
Replacement Carbon
Utilities
Indirect
Recovery Credit
Total Annual Costs (Line 5 + Line
6 + Line 7 + Line 8 + Line 9 -
Line 10)
Model Plant
Medium
$237,800
71,300
73,700
382,800
$12,400
23,800
47,100
34,200
94,200
(141,000)
$ 70,700
Large
$255,400
76,600
79,200
411,200
$12,400
23,800
47,100
34,800
99,900
(141,000)
$ 77,000

-------
Ms. Vickie Boothe
August 25, 1993
Page 5
Net Annual Costs

     Net annual costs represent the continual operating costs
incurred to keep the carbon adsorber in service, including credit
for the recovery of solvent from regeneration of the carbon bed.
The operating costs, as presented in lines 5-9 of Table 2, are
operating labor, maintenance, replacement carbon, utilities, and
indirect costs  (capital recovery, property taxes, insurance,
overhead, and administrative).  The operating costs are
$211,700/year for medium model plants and $218,000/year for large
model plants.  The recovery credit for both medium and large
model plants is $141,000/year, resulting in net annual costs
(line 11 of Table 2) of $70,700/year for medium model plants and
$77,000/year for large model plants.

Total MACT Costs

     Total MACT Cost = Annualized Costs + Net Annual Costs

Medium model plant:  $54,500/yr + $70,700/yr = $125,200/yr

Large model plant:   $58,540/yr + $77,000/yr = $135,540/yr


MACT COSTS - WATERBORNE MASKANTS

     MACT floor can be based on the substitution of waterborne
maskant for the solvent based maskant specified as baseline.  The
waterborne maskant requires a three tank system as opposed to the
single tank required for solvent based maskant.4  The waterborne
maskant requires stainless steel tanks, so the baseline tanks
cannot be used  (tanks used for solvent based maskant are
typically not constructed of stainless steel).  Waterborne
maskants also require a drying operation (ovens) to fully cure
the coating.  Solvent based maskants do not require this final
cure.

Tank and Oven Costs

     For medium model plants, a tank size of 20 feet x 10 feet  x
10 feet deep was used, and 30 feet x 10 feet x 10 feet deep for
large model plants.  The cost of the 20 foot long tank was quoted
as $45,000, and the 30 foot long tank was quoted as $50,000.5
The quoted prices include delivery charges.

     Waterborne maskant systems require two ovens.6  For medium
model plants, an oven size of 10 feet x 10 feet x 10 feat was
used for both ovens.  For large model plants, oven sizes of  '10
feet x 10 feet x 10 feet) and (10 feet x 10 feet x 30 feet long)
were used.  Two vendors quoted costs for these ovens.  The first
vendor quoted $37,500 for the small oven and $45,000 for the

-------
Ms. Vickie Boothe
August 25, 1993
Page 6
large oven.7  The second vendor quoted $48,000  for the small oven
and $69,500 for the large oven.8  For costing purposes,  the
average costs were used, or $42,700 for the small oven and
$57,300 for the large oven.

Annualized Capital Costs

     The total capital costs are equal to the cost of three tanks
and two ovens as specified above for each model plant.

Medium model plants: ($45,000/tank x 3 tanks) + ($42,700/oven x
                                              2 ovens) = $220,400

Large model plants: ($50,000/tank x 3 tanks) + $42,700 + $57,300
                                                       = $250,000

     Using the annualized capital costs equation presented above,
an interest rate of 7 percent, and an equipment life of 10 years,
the annualized costs by model plant are:

Medium model plant:  $31,380/yr

Large model plant:   $35,590/yr

Annual Costs - Ovens

      The annual operating costs for the ovens are comprised of
energy and maintenance costs.  One maskant manufacturer estimated
the annual operating costs to be $0.004572/ft2  of surface area
coverage.9  A second maskant manufacturer estimated these same
costs to be $0.00913/ft2 of surface area coverage.10  Insufficient
information was provided in these cost analyses to determine why
the cost presented by the second manufacturer was almost exactly
twice that of the first manufacturer.  Consequently, an average
of the two values, or $0.00685/ft2,  will be used for the cost
analysis.  Neither of the two maskant manufacturers mentioned a
difference in labor cost between solvent based and waterborne
maskants, so it will be assumed that the labor requirements are
the same for each type of maskant.

     Using the surface area coverage calculated below for maskant
cost, the annual costs are:

Medium model plant:  $0.00685/ft2 x 396,000 ft2/yr =  $2,700/yr

Large model plant:   $0.00685/ft2 x 858,000 ft2/yr =  $5,900/yr

-------
Ms. Vickie Boothe
August 25, 1993
Page 7
Maskant Cost

     In order to accurately compare cost, the equivalent volume
of waterborne maskant that will replace the baseline volume of
solvent based maskant must be determined.  The equivalent volume
is calculated using the percent by volume of solids and the dry
film thickness.

     One vendor of solvent based maskant reported that a typical
solvent based maskant is 25 percent by volume solids, requires a
0.012 inch dry film thickness, and costs $10 per gallon.   To
calculate the surface area coverage per gallon of maskant:

    1 square  foot of surface area  covered with a dry film
    thickness of 0.012 inches  (0.001  feet)  equates to a  solids
    volume  of 0.001 ft3.


1 ft2 surface area  x  1   ft3  solids x 0.25 aal solids =   33  ft2
0.001 ft3 solids      7.48 gal  solids     gal maskant     gal maskant


     One vendor of waterborne maskant reported that a typical
waterborne maskant is 44 percent by volume solids,12 requires  a
0.019 inch dry film thickness,13 and costs  $18 per gallon.14   To
calculate the surface area coverage per gallon of maskant:

    1 square  foot of surface area  covered with a dry film
    thickness of 0.019 inches  (0.0016  feet) equates  to a  solids
    volume  of 0.0016 ft.3


1 ft2 surface area  x  1   ft3  solids x 0.44 gal solids =   37  ft2
0.0016 ft3 solids     7.48 gal  solids     gal maskant     gal maskant


Surface area coverage (baseline):

Medium model plant:  12,000 gal maskant x 33 ft2/gal maskant =
                                                       396,000 ft2

Large model plant:   26,000 gal maskant x 33 ft2/gal  maskant =
                                                       858,000 ft2

Equivalent waterborne maskant volume:

Medium model plant:  396,000 ft2 x 1 gal maskant/37  ft2 =
                                               10,700 gal raasxant

Large model plant:    858,000 ft2 x 1 gal maskant/37  ft2 =
                                               23,200 gal maskant

-------
Ms. Vickie Boothe
August 25, 1993
Page 8
Incremental maskant cost:

Medium model plant: (10,700 gal/yr x $18/gal) -
                          (12,000 gal/yr x $10/gal) =  $72,600/yr


Large model plant: (23,200 gal/yr x $18/gal) -
                         (26,000 gal/yr x $10/gal) =  $157,600/yr

Total MACT Cost

     The total cost of implementing MACT is equal to the sum of
the annualized capital costs, annual costs, and the incremental
annual maskant cost.

Medium model plant:  $31,380/yr + $2,700/yr +  $72,600/yr =
                                                      $106,680/yr

Large model plant:   $35,590/yr + $5,900/yr + $157,600/yr =
                                                      $199,090/yr


References

 1.  Section 114 Questionnaire Response from Grumman Corporation
     in Bethpage, New York.

 2.  Section 114 Questionnaire Response from McDonnell Douglas
     Corporation in St. Louis, Missouri.

 3.  OAOPS Control Cost Manual. Fourth Edition, EPA-450/3-90-006,
     January 1990.  pp. 4-1 - 4-42.

 4.  Telephone Report.  K. Feser, PES, and B. Werkema, McDonnell
     Douglas, on January 15, 1993.

 5.  Telephone Report.  K. Feser, PES, and R. Beckner, Springs
     Fabrication, on January 26, 1993.

 6.  Reference 4.

 7.  Telephone Report.  K. Feser, PES, and D. Lauersdorf,
     Wisconsin Ovens, on February 1, 1993.

 8.  Telephone Report.  K. Feser, PES, and P. Averett, Photo
     Chemical Systems, on February 11, 1993.

 9.  "The Costs of Using Solvent Based Maskants Versus CAX-100-
     LA, a Waterborne Maskant," Product Brochure of Malek, Inc.
     p. 3.

-------
Ms. Vickie Boothe
August 25, 1993
Page 9
10.  "Water Based Versus Solvent Based Maskants," AC Products,
     Inc., June 1992, p. 6.

11.  Telephone Report.  K. Feser, PES, and S. Weinstein, AC
     Products, on December 15, 1992.

12.  Telephone Report.  K. Feser, PES, and M. Jaffari, Malek,
     Inc., on November 11, 1992.

13.  Reference 9.

14.  Telephone Report.  K. Feser, PES, and M. Jaffari, Malek,
     Inc., on December 16, 1992.

-------
                           MEMORANDUM
TO:       Vickie Boothe
          US EPA:BSD

FROM:     David Hendricks
          Pacific Environmental Services, Inc. (PES)

DATE:     February 8, 1994
          L:\N208

SUBJECT:  MACT Cost Analysis for Aircraft Depainting
     The purpose of this memo is to calculate and compare
baseline and MACT costs for aircraft depainting.  Baseline
consists of using methylene chloride based chemical strippers.
The MACT floor specifies no HAP emissions from chemical
depainting.  Three basic methods have been identified for meeting
the MACT floor.  These methods are (1) media blasting such as
plastic media and wheat starch; (2) both acidic and alkaline non-
HAP chemical strippers; and (3) reducing the amount of outer
surface area of the aircraft that is coated.  The data for the
first option was derived mainly from military facilities.  Since
it is unknown whether the available data is applicable to
commercial facilities, the cost impacts for the first option were
evaluated only for military model plants.  Similarly, the
available data for the second and third options were derived from
commercial facilities.  Since it is unknown whether the available
data is applicable to military facilities, and the third option
applies only to commercial aircraft,  the cost impacts for the
second and third options were evaluated only for commercial model
plants.  All impact analyses also include an exemption of 20
gallons of chemical stripper per aircraft for spot stripping and
decal removal.

     Tables 1, 2, and 3 summarize the baseline and MACT cost
impacts for each of the options.  The assumptions and
calculations used in determining these impacts are detailed
below.

     Table 1 summarizes the baseline and MACT costs for option 1.
As shown in line 12 of Table 1, implementation of MACT is

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-------
  Ms.  Vickie  Booths
  February 3,  1994
  Page 5
  expected to result in an annual cost of $168,400 for small model
  plants, $266,130 for medium model plants,  and $1,149,680 for
  large model plants.

      Table 2 summarizes the baseline and MACT costs for option 2.
  As shown in line 10 of Table 2, implementation of MACT is
  expected to result in an annual savings of $7,200 for small model
  plants and $23,590 for medium model plants.

      Table 3 summarizes the baseline and MACT costs for option 3.
 As shown in line 10 of Table 3, implementation of MACT is
  expected to result in an annual savings of $34,300 for small
 model plants and an annual cost of $374,350 for medium model
 plants.


 OPTION 1 - PLASTIC MEDIA BLASTING

 BASELINE

      The baseline has been defined as depainting aircraft with
 methylene chloride based stripers with no emission controls in
 place.   Many military facilities are currently using plastic
 media blasting.   Therefore,  for the purpose of this option, data
 from  military facilities will be used for both baseline and MACT.
 The total  outer surface area of aircraft reworked annually for
 each  model  plant is:

      Small  model plants1 - 137,900  ft2

      Medium model plant2-3  -  190,500 ft2

      Large  model plant4  - 1,032,000  ft2


 Baseline Costs

      A medium size  military  rework facility provided labor,
materials,  and utility  costs for methylene chloride depainting on
a cost per  square foot  of  outer surface area basis.5  These costs
are:

      Labor:         $3.57/ft2
     Materials:   .  $0,55/ft2
     Utilities:     $0.06/ft2

It will be assumed that these  costs remain constant for all model
plant sizes.

-------
Ms. Vickie Booths
February 8, 1994
Page 6
     Since there is no difference between the disposal of spent
stripper from military facilities and that from commercial
facilities, the disposal cost should also be the same.  Delta Air
Lines stated that depainting produces 0.029 gallons of waste
stripper for every square foot of surface area stripped, and
waste disposal costs are $6.00/gallon.6*7  Therefore, it costs
$0.17/ft2 for spent stripper disposal.

     Based on site visits and general knowledge of the industry,
virtually all aerospace facilities have a wastewater treatment
facility on-site to treat waste generated by a variety of
operations.  Consequently, the capital costs associated with
wastewater treatment from the depainting operation will not be
included in the cost analysis since these facilities are already
in place.

Labor cost for chemical depainting:

Small model plant:    137,900 ft2/yr x $3.57/ft2 =  $492,300/yr

Medium model plant:   190,500 ft2/yr x $3.57/ft2 =  $680,080/yr

Large model plant:  1,032,000 ft2/yr x $3.57/ft2 =  $3,684,240/yr


Material Costs:

Small model plant:    137,900 ft2/yr x $0.55/ft2 =  $75,840/yr

Medium model plant:   190,500 ft2/yr x $0.55/ft2 =  $104,770/yr

Large model plant:  1,032,000 ft2/yr x $0.55/ft2 =  $567,600/yr


Utility costs:

Small model plant:    137,900 ft2/yr x $0.06/ft2 =  $8,270/yr

Medium model plant:   190,500 ft2/yr x $0.06/ft2 =  $ll,430/yr

Large model plant:  1,032,000 ft2/yr x $0.06/ft2 =  $61,920/yr

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Ms. Vickie Boothe
February 8, 1994
Page 7
Spent stripper disposal costs:

Small model plant:    137,900 ft2/yr x $0.17/ft2 =  $23,440/yr

Medium model plant:   190,500 ft2/yr x $0.17/ft2 =  $32,380/yr

Large model plant:  1,032,000 ft2/yr x $0.17/ft2 =  $175,440/yr

Total Baseline Costs

     The total baseline costs equal the sum of the labor,
material, utility, and disposal costs for each model plant.
 Labor costs

 Material costs

 Utility costs

 Disposal costs

 Total Costs
    Small

$492,300/yr

  75,840/yr

   8,270/yr

  23,440/yr

$599,850/yr
  Model Plant

   Medium

$680,080/yr

 104,770/yr

  11,430/yr

  32,380/yr

$828,660/yr
     Large

$3,684,240/yr

   567,600/yr

    61,920/yr

   175,440/yr

$4,489,200/yr
MACT COSTS

     As previously stated, the MACT floor specifies no HAP
emissions from chemical depainting.  This can be achieved through
the use of media blasting techniques.  Plastic media blasting
will be used for the purpose of evaluating cost impacts since it
is already in use at several military facilities.

Annual Costs

     The costs associated with implementing plastic media
blasting are for capital equipment, labor, materials, utility,
and waste disposal.  The same facility that provided cost per
square foot of surface area data for methylene chloride based
stripping also provided the same data for plastic media
blastina.8  These costs are:
     Labor:
     Materials:
     Utilities:
  $2.80/ft2
  $2.37/ft2
  $0.15/ft2

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Ms. Vickie Booths
February 8, 1994
Page 8
As with methylene chloride based stripping, it will be assumed
that these values remain constant for all model plant sizes.

     One facility estimated the disposal cost of the paint chips
and spent blasting media to be $900 per aircraft.9  This facility
strips only one type of aircraft, which has an outer surface area
of 11,000 square feet.10  The disposal cost then equates  to $0.08
per square foot.

     Facilities that have implemented plastic media blasting
systems typically use an existing building for the operation
rather than constructing a new building.  Consequently,  no
building costs will be included in the total capital cost
calculations.

Labor costs:

Small model plant:    137,900 ft2/yr x $2.80/ft2 =  $386,120/yr

Medium model plant:   190,500 ft2/yr x $2.80/ft2 =  $533,400/yr

Large model plant:  1,032,000 ft2/yr x $2.80/ft2 =  $2,889,600/yr


Material costs:

Small model plant:    137,900 ft2/yr x $2.37/ft2 =  $326,820/yr

Medium model plant:   190,500 ft2/yr x $2.37/ft2 =  $451,490/yr

Large model plant:  1,032,000 ft2/yr x $2.37/ft2 =  $2,445,840/yr


Utility costs:

Small model plant:    137,900 ft2/yr x $0.15/ft2 =  $20,680/yr

Medium model plant:   190,500 ft2/yr x $0.15/ft2 =  $28,580/yr

Large model plant:  1,032,000 ft2/yr x $0.15/ft2 =  $154,800/yr

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February 8, 1994
Page 9
Disposal costs:

Small model plant:    137,900  ft2/yr x $0.08/ft2 = $ll,030/yr

Medium model plant:   190,500  ft2/yr x $0.08/ft2 = $15,240/yr

Large model plant:  1,032,000  ft2/yr x $0.08/ft2 = $82,560/yr


Capital Costs

     Capital costs for plastic media blasting systems  can vary
greatly depending on the capabilities of the  system,
sophistication of controls, and number of blasting guns.   One
facility reported a capital cost  of $250,000  for a small  plane
facility.11  Another facility  reported a  capital cost of $700,000
for a large plane facility.1^   This cost  was also used for medium
facilities.

Total capital costs:

     Small model plants:   $250,000

     Medium model plants:  $700,000

     Large model plants:   $700,000


Annualized Capital Costs

     The annualized capital costs were calculated from the
following equation:
                  Annualized Costs  =  TCC
                                        (1+7)" - 1.
     where,

     TCC = Total Capital  Cost
     i   = Interest Rate
     n   = Equipment  Life (years)

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Ms. Vickie Booths
February 8, 1994
Page 10
     No information on the life of the blasting equipment could
be obtained other than it is indefinite with proper maintenance.
Therefore, 20 years will be used for the equipment life.  Using
an interest rate of 7 percent and the total capital costs
presented above, the annualized costs by model plant are:

     Small model plant:  $23,600/yr

     Medium model plant: $66,080/yr

     Large model plant:  $66,080/yr

Total MACT Cost

     The total MACT cost is the sum of the labor, material,
utility, disposal, and annualized costs for the plastic media
blasting systems.
 Labor
 costs

 Material
 costs

 Utility
 costs

 Disposal
 costs

 Annualized
 costs

 Total
 Costs

Cost Impact
    Small

$386,120/yr


 326,820/yr


  20,680/yr


  11,030/yr


  23,600/yr


$768,250/yr
   Model Plant

     Medium

  $533,400/yr


   451,490/yr


    28,580/yr


    15,240/yr


    66,080/yr


$l,094,790/yr
     Large

$2,889,600/yr


 2,445,840/yr


   154,800/yr


    82,560/yr


    66,080/yr


$5,638,880/yr
     The total cost impact of implementing the MACT standard is
equal to the total MACT costs minus the total baseline costs.

Small model plants:  $763,250/yr - $599,850/yr = $168,400/yr

Medium model plants: $1,094,790/yr - $828,660/yr = $266,l30/yr

Large model plants:  $5,633,880/yr - $4,489,200/yr = $1,149,680/yr

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Ms. Vickie Boothe
February 8, 1994
Page 11
OPTION 2 - NON-HAP STRIPPER AND
OPTION 3 - REDUCED PAINT SCHEME

BASELINE

     The baseline for Options 2 and 3 has been defined as
depainting fully-painted aircraft with methylene chloride based
chemical strippers.  Since Option 2 and 3 are demonstrated  at
commercial facilities, data for the baseline has been obtained
from commercial facilities.  The following parameters define
baseline:

Total number of aircraft reworked annually

     Small model plant        -    17 narrow body

     Medium model plant13-14    -    35 narrow body
                                   11 wide body

The number of aircraft reworked annually for the small model
plant was extrapolated from the medium model plant data.  Total
outer surface area of aircraft reworked annually:

     Small model plant15       -  163,900 ft2

     Medium model plant16      -  489,610 ft2

     From data provided by TWA and Delta, it takes 0.037 gal/ft2
to depaint aircraft using methylene chloride based strippers.17-18
Baseline stripper usage was calculated using these data and the
baseline outer surface area per model plant.  Additionally, Delta
Air Lines specified that 0.77 gallons of stripper waste is
disposed of per gallon of original stripper used.19   Delta Air
Lines also provided the cost of stripper and disposal at
$14.35/gal and $6.00/gal, respectively.20  TWA stated that
approximately 250 man-hours are used to depaint a narrow body
aircraft and 600 man-hours for a wide body aircraft.21  TWA's
labor costs were listed as $40 per hour,22^

Stripper usage and disposal:

Small model plant:  163,900 ft2/yr x 0.037 gal/ft2 =  6,060 gal/yr

       6,060 gal/yr x 0.77 gal waste/gal = 4,670 gal waste/yr

Medium model plant: 489,610 ft2/yr x 0.037 gal/ft2 =  13,120  gal/yr

     13,120 gal/yr x 0,77 gal wasra/gal = 13,950 gal waste/yr

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Ms. Vickie Boothe
February 8, 1994
Page 12
Stripper Cost:

Small model plant:   6,060 gal/yr x $14.35/gal =  $86,960/yr

Medium model plant: 18,120 gal/yr x $14.35/gal =  $260,020/yr


Waste Stripper Disposal Cost:

Small model plant:   4,670 gal/yr x $6.00/gal =  $28,020/yr

Medium model plant: 13,950 gal/yr x $6.00/gal =  $83,700/yr


Labor cost for chemical depainting:

Narrow body aircraft:   250 man-hours/aircraft x $40/man-hours =
                        $10,000/aircraft

Wide body aircraft:   600  man-hours/aircraft x $40/man-hours =
                      $24,000/aircraft


Small model plant:    17 aircraft/yr x $10,000/aircraft =
                      $170,000/yr

Medium model plant:   (35  aircraft/yr x $10,000/aircraft)  +
                      (11  aircraft/yr x $24,000/aircraft)  =
                      $614,000/yr

     Based on site visits and general knowledge of the industry,
virtually all aerospace facilities have a wastewater treatment
facility on-site to treat waste generated by a variety of
operations.  Consequently, the capital costs associated with
wastewater treatment from the depainting operation will not be
included in the cost analysis since these facilities are already
in place.

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Ms. Vickie Boothe
February 8, 1994
Page 13
Total depainting costs:

                        Small Model  Plants   Medium Model Plants

 Cost of stripper               $86,960/yr        $260/020/yr

 Cost of spent                   28,020/yr          83,700/yr
 stripper disposal

 Labor costs for                170,000/yr         614,000/yr
 depainting

           Total Costs         $284,980/yr        $957,720/yr

OPTION 2 - NON-HAP STRIPPER

MACT COSTS

     As stated previously, this option is based on using non-HAP
strippers.  At least one commercial  facility uses non-HAP
strippers to depaint aircraft.  Data from this facility will be
used for the purpose of this option wherever possible.
Additionally, 20 gallons of chemical stripper that contains HAP's
per aircraft stripped will be allowed as an exemption.

     Delta Air Lines stated that 0.042 gallons of non-HAP
stripper is used per square foot of aircraft stripped.23  MACT
stripper usage was calculated using these data and the outer
surface area per model plant.  The stripper is disposed as waste
into on-site wastewater treatment facilities.  As stated
previously, virtually all aerospace  facilities have a wastewater
treatment facility on-site to treat waste generated by a variety
of operations.  Consequently, the capital costs associated with
wastewater treatment will not be included in the cost analysis
since these facilities are already in place.  Delta Air Lines
also stated that the cost of stripper is $14.66/gal.24  TWA
stated that approximately 250 man-hours are used to depaint a
narrow body aircraft and 600 man-hours for a wide body aircraft.
TWA's labor costs were listed as $40 per hour.

Non-HAP Stripper Usage:

Small model plant:  163,900 ft*/yr  x  0.042 gal/ft2 = 6,880 gal/yr

Medium model plant: 489,610 ft2/yr  x  0.042 gal/ft2 = 20,560 gal/yr

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Ms. Vickie Boothe
February 8, 1994
Page 14
Stripper Cost:

Small model plant:  6,880 gal/yr x $14.66/gal =  $100/860/yr

Medium model plant:  20,560 gal/yr x $14.66/gal =  $301,.410/yr


Labor cost for chemical depainting:

Narrow body aircraft:   250 man-hours/aircraft x $40/man-hours =
                        $10,000/aircraft

Wide body aircraft:   600  man-hours/aircraft x $40/man-hours =
                      $24,000/aircraft

Small model plant:    17 aircraft/yr x $10,000/aircraft =
                      $170,000/yr

Medium model plant:   (35  aircraft/yr x $10,000/aircraft)  +
                      (11  aircraft/yr x $24,000/aircraft)  =
                      $614,000/yr

     Since the total number of aircraft reworked annually is 17
for a small model plant and 46 for a medium model plant, The
exempted use of methylene chloride based stripper will equal the
number of aircraft stripped per model plant multiplied by the 20
gallons.  As stated in the baseline section, Delta Air Lines
generates 0.77 gallons of waste per gallon of stripper used.
Delta Air Lines also stated that it costs $6.00/gallon to dispose
of waste stripper.  The MACT methylene chloride based stripper
usage and disposal by model plant are:

HAP Stripper Usage and Disposal:

Small model plant:  17 aircraft/yr x 20 gal/aircraft = 340 gal/yr

               340 gal/yr x 0.77 gal waste/gal = 260 gal wasts/yr

Medium model plant: 46 aircraft/yr x 20 gal/aircraft =920 gal/yr

               920 gal/yr x 0.77 gal waste/gal =710 gal waste/yr

HAP Stripper Cost:

Small model plant:  340 gal/yr x $14.35/gal = $4,880/yr

Medium model plant:  920 gal/yr x $14.35/gal = $13,200/yr

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Ms. Vickie Boothe
February 8, 1994
Page 15
HAP Stripper Disposal Cost:

Small model plant:  340 gal/yr x $6.00/gal - $2/040/yr

Medium model plant:  920 gal/yr x $6.0Q/gal = $5,520/yr

Total MACT Cost

The total MACT cost is the sum of the material, disposal, and
labor costs.

                                 Small Model   Medium Model
                                 Plants        Plants

   Cost  of  non-HAP stripper       $100,860/yr    $301,410/yr

   Cost  of  methylene chloride         4,880/yr      13,200/yr
   based stripper

   Cost  of  spent  methylene            2,040/yr       5,520/yr
   chloride based stripper
   disposal

   Labor costs  for depainting       170,000/yr     614,000/yr

            Total Costs           $277,780/yr    $934,130/yr

Cost Impact

Actual  cost of implementing the MACT standard is equal to the
total MACT cost minus the baseline cost.

Small model plant:   $277,780/yr - $284,980/yr = ($7/200/yr)

Medium  model plant:  $934,130/yr - $957,720/yr = ($23,590/yr)

The negative values indicate an overall net savings for the model
plants  to  implement the MACT standard.


OPTION  3 - REDUCED PAINT SCHEME

MACT COSTS

     As stated previously, this option is based on partially
painting the aircraft and polishing the unpainted bare metal
portion of the aircraft.  This option is demonstrated at
commercial facilities and data from these facilities is used
below.  Although  the cost  impact of a reduction in paint usage is
not taken  into account in this analysis, polishing cost must be

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Ms. Vickie Booths
February 8, 1994
Page 16
included since polishing unpainted bare metal is necessary.
Additionally, polishing is performed more frequently than
repainting and, therefore, the number of aircraft reworked
annually increases.  The following parameters define MACT:

Total number of aircraft reworked annually:

     Small model plant25       -  56 narrow body

     Medium model plant26      -  107 narrow body
                                  74 wide body

Total outer surface area of aircraft reworked annually

     Small model plant27       -  379,048 ft2

     Medium model plant28      -  2,258,118 ft2

Polishing Costs

     Based on information provided by American Airlines, 150
labor hours are required to polish a narrow body aircraft, and
400 labor hours are required to polish a wide body aircraft.
American also reported the cost of the polish to be $27.50 per
pound.29  USAir reported costs of $6.09 and  $25.50 per gallon  of
two polishes they use.30  American uses 2 pounds of polish  for a
narrow body aircraft and 5 pounds for a wide body aircraft.31
USAir, which only services narrow body aircraft, reported using
0.5 gallon of each polish per narrow body aircraft.32
Extrapolating USAir's narrow body usage to wide body usage on the
basis that American Airlines uses 2.5 times the amount of polish
on a wide body than on a narrow body aircraft, USAir would use
1.25 gallons of each polish on a wide body aircraft.  Since the
cost and usage of the polish is an average of data provided by
USAir and American, the same polish cost will be used whether 5
percent or 40 percent of the outer surface area is painted.

Cost of Polish:

American - narrow body:  2 Ib/aircraft x $27.50/lb = $55/aircraft

        - wide body:    5 Ib/aircraft x $27.50/lb = $140/aircraft

USAir - narrow body:  (0.5 gal/aircraft x $6.09/gal) +
                      (0.5 gal x $25.50/gal) = $18/aircraft

     - wide body:      (1.25 gal/aircraft x $6.Q9/gal) +
                       (1.25 gal x $25.50/gal) = $39/aircraft

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Ms. Vickie Boothe
February 8, 1994
Page 17
Average narrow body:  ($55 + $18)/2 = $37/aircraft

Average wide body:   ($140 + $39)/2 = $89/aircraft


Small model plant:   56 aircraft/yr x $37/aircraft = $2,070/yr

Medium model plant: (107 aircraft/yr x $37/aircraft) +
                    (74 aircraft/yr x $89/aircraft) = $10,550/yr

Labor cost to polish:

     The cost and labor hours per aircraft are from data provided
by American Airlines.33  This facility paints up to  60 percent of
their planes.

Narrow body:  150 hours/aircraft x $18/hour = $2,700/aircraft

Wide body:    400 hours/aircraft x $18/hour = $7,200/aircraft


Small model plant: 56 aircraft/yr x $2,700/aircraft = $151,200/yr

Medium model plant:  (107 aircraft/yr x $2,700/aircraft) +
                     (74 aircraft/yr x $7,200/aircraft)  =
                     $821,700/yr

     Since 55 percent more of the surface area of the aircraft
must be polished when only 5 percent of the surface area is
painted, it will be assumed that the labor requirements are 55
percent greater than that calculated above.

Small model plant:  $151,200/yr x 1.55 = $234,360/yr

Medium model plant: $821,700/yr x 1.55 = $1,273,630/yr

Total polishing costs:

Small model plant:  $27070/yr + $234,360/yr = $236,430/yr

Medium model plant:  $10,550/yr + $1,273,63Q/yr = $1,284,180/yr

Depainting Costs

     The portion of the aircraft that is painted must also be
stripped.  For aircraft with 5 percent of the surface area

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Ms. Vickie Booths
February 8, 1994
Page 18
painted, stripping costs are assumed to be 5 percent of the cost
to strip a fully painted aircraft.

Small model plant:  $284,980/yr x 0.05 = $14,250/yr

Medium model plant:  $957,720/yr x 0.05 = $47,890/yr

Total MACT Cost

Total MACT cost is equal to the sum of the polishing costs and
depainting costs.

Small model plant:  $236,430/yr + $14,250/yr = $250,680/yr

Medium model plant: $1,284,180/yr + $47,890/yr = $1,332,070/yr

Cost Impact

Actual cost of implementing the MACT standard is equal to the
total MACT cost minus the baseline cost.

Small model plant:   $250,680/yr - $284,980/yr = ($34,300/yr)

Medium model plant:  $1,332,070/yr - $957,720/yr = $374,350/yr

The negative values indicate an overall net savings for the model
plants to implement the MACT standard.


References

 1. Section 114 Questionnaire Response  from Grumman Corporation
    St. Augustine Operations Facility in St. Augustine, Florida.

 2. Section 114 Questionnaire Responses from Lockheed Aircraft
    Services Ontario Facility in Ontario, California.

 3. Section 114 Questionnaire Responses from Naval Aviation
    Depot in Alameda, California.

 4. Section 114 Questionnaire Response  from Warner Robins Air
    Logistics Center, Robins Air Force  Base, in Warner Robins,
    Georgia.

 5. Telephone Report.  K.  Feser, PES, and J. Tuan, Naval
    Aviation Depot - Alameda, on February 4, 1993.

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Ms. Vickie Boothe
February 8, 1994
Page 19
 6. Paint Stripping, Processes developed and used  by Delta Air
    Lines, Inc.  Technical Operations Center, Atlanta,  Georgia,
    May 19, 1993.

 7. Letter.  D. Collier, Air Transport Association,  to  V.
    Boothe, EPA:ESD.  June 7, 1993.  Information on  commercial
    depainting.

 8. Reference 5.

 9. Reference 2.

10. Reference 2.

11. Reference 3.

12. Reference 4.

13. Section 114 Questionnaire Response from Trans  World Airlines
    Ground Operations Center in Kansas City, Missouri.

14. Plant Visit Questionnaire Response from United Airlines
    Maintenance Operation Center  in San Francisco, California.

15. References  13 and 14.

16. References  13 and 14.

17. Telephone Report.   D. Hendricks, PES, and G. Mundy,  Trans
    World Airlines, on  February 11, 1993.

18. Reference 6.

19. Reference 6.

20. Reference 6.

21. Reference 17.

22. Reference 13.

23. Reference 6.

24. Reference 6.

25. Section 114 Questionnaire Response from USAir  Heavy
    Maintenance Facility in Winston-Salem, North Carolina.

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Ms. Vickie Boothe
February 8, 1994
Page 20
26. Section 114 Questionnaire Response from American Airlines
    Maintenance and Engineering Center in Tulsa,  Oklahoma.

27. Reference 25.

28. Reference 26.

29. Telephone Report.  K. Feser, PES, and B. Curtis, American
    Airlines, on February l, 1993.

30. Telephone Report.  K. Feser, PES, and A. Wipfield,  USAir, on
    February 4, 1993.

31. Reference 29.

32. Reference 25.

33. Reference 26.

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                           MEMORANDUM
TO:       Vickie Booths
          US EPArESD

FROM:     David Hendricks
          Pacific Environmental Services, Inc. (PES)

DATE:     August 25, 1993
          L:\N019

SUBJECT:  MACT Cost Analysis for Hand Wipe Cleaning
     The purpose of this memo is to calculate and compare
baseline and MACT cost impacts for hand wipe cleaning operations.
Baseline consists of using a cleaning solvent such as methyl
ethyl ketone (vapor pressure 71 mmHg at 20°C).  In addition, it
is assumed that no housekeeping system is utilized which is
focused toward capturing fugitive emissions.  The MACT floor
specifies that hand wipe cleaning solvents are chosen from an
approved list of solvents or comply with a vapor pressure limit
of 45 mmHg at 20°C.  Emission reductions are achieved through
product substitutions such as aqueous and low vapor pressure
cleaners and the implementation of a housekeeping system.  The
housekeeping system includes closed containers for solvent laden
rags and for storage of solvent.  No significant differences were
identified for OEM versus rework or military versus commercial
hand wipe cleaning operations; therefore, the cost impacts are
differentiated only by model plant size.

     Table 1 summarizes the baseline and MACT cost impacts.  As
presented on line 11 of Table 1, implementation of MACT is
expected to result in a cost of $7,030/yr for small model plants
and $3,510/yr for medium model plants, and an annual savings of
$9,260/yr for large model plants.  The assumptions and
calculations used in determining these impacts are detailed
below.

BASELINE

     The baseline for hand wipe cleaning operations has been
defined as using a cleaning solvent such as methyl ethyl ketone

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Ms. Vickie Boothe
August 25, 1993
Page 2
                             TABLE 1

        ANNUAL COSTS TO IMPLEMENT HAND WIPE CLEANING MACT
Item
1. Baseline Solvent Cost
2. Baseline Waste Disposal
Cost
3. Total Baseline Cost
(Line 1 + Line 2)
4 . MACT Solvent Cost
5. MACT Solvent Testing
Cost
6. MACT Waste Disposal
Cost
7. MACT Other Material
Cost
8. MACT Implementation
Cost
9. MACT Recurring
Education Cost
10. Total MACT Cost
(Line 4 + Line 5 +
Line 6 + Line 7 +
Line 8 + Line 9)
11. Cost Impact
(Line 10 - Line 3)
Model Plant
Small
$7,350
1,330
8,680
5,380
900
1,080
6,890
630
830
15,710
$7,030
Medium
$196,000
35,560
231,560
143,360
900
28,890
22,930
16,770
22,220
235,070
$3,510
Large
$882,000
160,000
1,042,000
645,120
900
130,000
81,260
75,460
100,000
1,032,740
($9,260)
Note:  Values in parentheses represent a cost savings to the
model plant.

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August 25, 1993
Page 3


(vapor pressure 71 mmHg at 20°C).  In addition, it is assumed
that no housekeeping system is utilized which is focused toward
capturing fugitive emissions.  From Table 6-9 of the draft BID
Chapter 6, the average annual hand wipe cleaning emissions was
calculated to be 58 lb/employee.  Assuming an average solvent
density of 8 Ib/gal, the average solvent usage was calculated to
be 7 gal/employee.  Conventional, higher vapor pressure solvents
vary in cost depending on type of solvent and amount of solvent
purchased.  Typical solvent costs range from $5/gal to $9/gal.1
For the purposes of determining cost impacts, a value of $7/gal
was assumed.  The model plants are sized by number of employees
with small, medium, and large facilities assigned 150, 4,000, and
18,000 employees, respectively.

     For the purposes of the cost impacts, it was assumed that
the following parameters define baseline:

Annual Solvent Purchase Cost by Model Plant:

Small model plant:  150 emp x 7 gal/emp-yr x $7/gal = $7,350/yr

Medium model plant:  4,000 emp x 7 gal/emp-yr x $7/gal =
                                             $196,000/yr

Large model plant:  18,000 emp x 7 gal/emp-yr x $7/gal =
                                             $882,000/yr

     The annual cost to dispose of solvent-laden rags was
estimated at $160,000/yr by one facility classified as a large
aerospace model plant.   This cost includes labor,  transportation
of waste, and off-site disposal fees.  The costs have been scaled
to the small and medium model plants based on number of
employees.

Annual Solid Waste Disposal Cost by Model Plant:

Small model plant:  (150 emp/18,000 emp) x $160,000 = $l,330/yr

Medium model plant: (4,000 emp/18,000 emp) x $160,000 =
                                             $35,560/yr

Large model plant:  $160,000/yr

Total Baseline Costs by Model Plant:

Total Baseline Cost =    solvent cost + disposal cost

Small model plant:  $7,350/yr + $l,330/yr = $8,680/yr

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Ms.  Vickie Boothe
August 25, 1993
Page 4


Medium model plant: $196,000/yr + $35,560/yr = $231,560/yr

Large model plant:  $882/000/yr + $160,000/yr = $1,042,000/yr


MACT COSTS

     As stated previously, the MACT floor specifies using
cleaning solvents from an approved list or with a vapor pressure
limit of 45 mmHg at 20°C.  In addition, a housekeeping system
must be implemented which focuses on capturing fugitive emissions
as demonstrated by one aerospace facility.3  The  costs  of
implementing the MACT floor control measures are derived
primarily from data provided by one aerospace facility.

     Several companies have developed and marketed low vapor
pressure solvents to the aerospace industry.  The cost for
replacement solvents varies by type of solvent and amount of
solvent purchased.  Based on data provided by a vendor, the
estimated cost of a substitute solvent is $16/gal.4  Total annual
solvent usage is reduced by 68 percent.5

Annual Solvent Purchase Cost by Model Plant:

Small model plant:  150 emp x 7 gal/emp x  (1-0.68) x $16/gal =
                                             $5,380/yr

Medium model plant:  4,000 emp x 7 gal/emp x (1-0.68) x $16/gal =
                                             $143,360/yr

Large model plant:  18,000 emp x 7 gal/emp x (1-0.68) x $16/gal =
                                             $645,120/yr

In addition to purchase costs, facilities must test every solvent
that is not on the approved list for vapor pressure.  Some
facilities are currently using low vapor pressure solvents that
may be included on the list.  In addition to these substitutes,
each facility uses approximately three other solvents that must
be tested for vapor pressure.6  This testing may  occur  once a
year or less, depending on how often a facility implements new
solvents.  Typical vapor pressure tests for solvent mixtures
range between $150 to $400.7  Since many  low vapor pressure
solvents are complex mixtures, the cost of $300 per test will be
used in this memo.  The testing costs are not scaled to model
plant size since it is assumed model plants would utilize the
same breakdown of solvents.

               Testing Cost by Model Plant:  3 x $300 = $900/yr

-------
Ms. Vickie Boothe
August 25, 1993
Page 5


     A large aerospace model plant reported the implementation of
a disposal system that improved the capture of fugitive
emissions.  This system involves using sealable drums and bags to
capture fugitive emissions from solvent-laden rags.  The rags are
then disposed of by off-site incineration.  The cost includes
labor, transportation of waste, and off-site disposal fees.  This
facility had already implemented these MACT control measures and
reported disposal costs of $130,000.  For the purposes of
calculating cost impacts, a cost of $130,000/yr was used for the
disposal of solvent-laden rags for a large model plant.8  The
costs have been scaled to the small and medium model plants based
on number of employees.

Annual Solid Waste Disposal Cost by Model Plant:

Small model plant: (150 emp/18,000 emp) x $130,000 = $l,080/yr

Medium model plant: (4,000 emp/18,000 emp) x $130,000 =
                                             $28,890/yr

Large model plant:  $130,000/yr

     Additionally, sealable drums and bags must be purchased in
order to provide a capture mechanism for the solvent-laden rags
and other materials.  The annual cost to purchase drums and
aluminized bags was estimated at approximately $75,000/yr by the
above facility classified as a large model plant.9  The costs
have been scaled to the small and medium model plants based on
number of employees.

Annual Purchase Cost for Fiber Drums and Aluminized Bags:

Small model plant: (150 emp/18,000 emp) x $75,000 = $630/yr

Medium model plant: (4,000 emp/18,000 emp) x $75,000 = $16,670/yr

Large model plant:  $75,000/yr

     When dealing with large volumes of compressible solid waste,
some aerospace facilities utilize compactors to reduce the volume
of this waste.  A facility classified as a large model plant
purchased one compactor to handle solid waste.  A capital cost of
$44,000 was determined for the purchase and installation a
compactor for a large aerospace model plant.10

     The annualized costs were calculated by the following
equation:

-------
Ms. Vickie Boothe
August 25, 1993
Page 6
                                         7
                 Annualized  Costs  =  TCC
                                        (!+/)" - 1


     where,

     TCC = Total Capital Cost
     i   = Interest Rate
     n   = Equipment Life (years)

An interest rate of 7 percent and an equipment life of 10 years
was assumed.  The annualized costs for a large model plant are:

Annualized Compactor Cost =  $6,260/yr.


The annualized compactor costs are not scaled to small and medium
model plants since it is assumed the model plants would utilize
the same size and type of compactor.  Total material costs
(excluding solvent) equal the costs of drums and bags plus the
annualized compactor cost.

Annual Other Material Costs by Model Plant:

Small model plant:   $630/yr + $6/260/yr = $6,890/yr

Medium model plant: $16,670/yr + $6,260/yr = $22,930/yr

Large model plant:  $75/000/yr + $6,260/yr = $81/260/yr

     Finally, implementing new solvents in production involves
implementation and education costs.  Implementation costs include
engineering specification revisions, production planning document
changes, process control standard revisions, and internal
research and development to test and qualify low vapor pressure
solvents.  Training costs to educate workers on the new solvent
cleaning procedures and the hazardous waste management and
collection system must also be included.  Education costs include
instructor labor, lost labor in class, creation of training
materials, and creation of awareness posters and signs.  Table 2
summarizes the one time implementation costs for a large model
plant.  Table 3 summarizes the annual recurring education costs.
The costs were obtained from a large model plant11 and have been
scaled to the small and medium model plants based on number .of
employees.

-------
Ms. Vickie Boothe
August 25, 1993
Page 7
                             TABLE 2

                   IMPLEMENTATION COST SUMMARY
Item
1. Engineering Specification
Revision
2 . Production Planning
Documents Changes
3 . Process Control Standard
Revisions
4 . Education
Instructor Labor
Lost Labor in Class
Creation of Training
Materials
5. Internal Research and
Development to Test and
Quantify Solvents
6 . Total Cost
(Line 1 + Line 2 + Line 3
+ Line 4 + Line 5)
Model Plant
Small
$1,130
210
40
380
2,000
330
330
$4,420
Medium
$30,000
5,560
1,110
10,000
53,330
8,890
8,890
$117,780
Large
$135,000
25,000
5,000
45,000
240,000
40,000
40,000
$530,000
                             TABLE 3

                 ANNUAL RECURRING EDUCATION COSTS
Item
1 . Education
Instructor Labor
Lost Labor in Class
Training Materials
2. Total Cost
Model Plant
Small
$90
660
80
$830
Medium
$2,440
17,560
2,220
$22,220
Large
$11,000
79,000
10,000
$100,000

-------
Ms.  Vickie Boothe
August 25, 1993
Page 8


     The annual!zed implementation costs were calculated by the
above annualized cost equation.  An interest rate of 7 percent
and a life of 10 years was assumed.

Annualized Implementation Cost:

Small model plant:  $630

Medium model plant:  $16,770

Large model plant:  $75,460

Total MACT Costs

Total MACT Floor Costs by Model Plant:

Total MACT Cost  = solvent cost +  solvent testing cost +
                   disposal cost + other material cost +
                   implementation  cost + annual education cost


Small model plant:  $5,380/yr + $900/yr + $l,080/yr + $6,890/yr
                              + $630/yr + $830/yr =  $15,710/yr

Medium model plant: $143,360/yr +  $900/yr + $28,890/yr
          + $22,930/yr + $16,770/yr + $22,220/yr = $235,070/yr

Large model plant:  $645,120/yr +  $900/yr + $130,000/yr
        + $81,260/yr + $75,460/yr  + $100,000/yr = $1,032,740/yr


Cost Impacts

     The cost impact is calculated by subtracting the baseline
costs from the MACT costs:

Small model plant:  $15,710/yr - $8,680/yr = $7,030/yr

Medium model plant:  $235,070/yr - $231,560/yr = $3,510/yr

Large model plant:  $1,032,740/yr  - $1,042,000/yr = ($9,260/yr)


References

 1.  Letter.  T. Phillips, Lockheed, to D. Hendricks, PES.  June
     4, 1993.  Comments and questions about the MACT cost
     analysis for hand wipe cleaning.

-------
Ms. Vickie Boothe
August 25, 1993
Page 9


 2.  Reference 1.

 3.  Letter.  T. Phillips, General Dynamics, to V. Boothe,
     EPA:ESD.  January 20, 1993.  Alternative Cleanup Solvent
     Strategy for Aerospace CTG-Recently Implemented General
     Dynamics Fort Worth Division Program.

 4.  Telephone Report.  K. Feser, PES, and a Dynamold
     representative on August 17, 1993.  Cost of low vapor
     pressure solvent.

 5.  Reference 1.

 6.  Section 114 Questionnaire Responses.

 7.  Telephone Report.  K. Feser, PES, and M. Watley, South Coast
     Air Quality Management District, on August 9, 1993.  Cost of
     vapor pressure tests.

 8.  Letter.  T. Phillips, Lockheed, to D. Hendricks, PES.  March
     19, 1993.  Response to inquiry from D. Hendricks dated
     2/4/93 concerning cost information on product substitution
     of low vapor pressure solvents at Lockheed.  Non-proprietary
     version.

 9.  Reference 8.

10.  Telephone Report.  G. Pagett, PES, and S. Knowak, Compaction
     Technology, Inc., on May 18, 1993.  Cost information on
     compactors.

11.  Reference 1.

-------
                           MEMORANDUM
TO:       Vickie Booths
          US EPA:BSD

FROM:     David Hendricks
          Pacific Environmental Services, Inc. (PES)

DATE:     August 25, 1993
          L:\N019

SUBJECT:  MACT Cost Analysis for Spray Gun Cleaning
     The purpose of this memo is to calculate and compare
baseline and MACT costs for spray gun cleaning.  Baseline
consists of a combination of enclosed spray gun cleaners and
unlimited hand cleaning.  The MACT floor specifies enclosed spray
gun cleaners, cabinet type gun cleaners, vat cleaning using
unatomized spray, and atomized spray into a waste container
fitted with a capture device designed to capture atomized solvent
emissions.  For the purpose of the impact analysis, it will be
assumed that each facility uses enclosed spray gun cleaners.
There is no difference in implementing MACT for commercial versus
military or OEM versus rewor.k facilities; therefore, the impact
analysis was completed only for different size model plants.

     Table 1 summarizes the baseline and MACT costs.  As
presented in line 9 of Table 1, the implementation of MACT is
expected to result in an annual savings of $16,720 for small
model plants, $22,100 for medium model plants, and $28,000 for
large model plants.  The assumptions and calculations used in
deriving these costs are detailed below.

BASELINE

     Baseline consists of a combination of enclosed spray gun
cleaners and unlimited hand cleaning.  Table 2 presents the
baseline values for the number of enclosed spray gun cleaners in
use and the usage of spray gun cleaning solvent for each model
plant size.  Also included in the table are the values of these
parameters that will be used for the MACT cost analysis.

-------
Ms. Vickie Boothe
August 25, 1993
Page 2
                               TABLE 1

           ANNUAL COST TO IMPLEMENT SPRAY GUN CLEANING MACT
Item
1. Baseline Annual! zed Costs
2. Baseline Solvent Costs
3. Baseline Solvent Disposal
Costs
4. Tbtal Baseline Costs
(Line 1 + Line 2 + Line 3)
5. MACT Annualized Costs
6. MACT Solvent Costs
7. MACT Solvent Disposal
Costs
8. Total MACT Cost
(Line 5 + Line 6 + Line 7)
9. Cost Impact
(Line 8 - Line 4)
Model Plant
Small
$270
16,800
6,170
23,240
830
4,160
1,530
6,520
(16,720)
Medium
$550
22,800
8,380
31,730
1,100
6,240
2,290
9,630
(22,100)
Large
$830
29,200
10,730
40,760
1,380
8,320
3,060
12,760
(28,000)
Note:  Values in parentheses represent a cost savings to the model
plant.

                                TABLE 2

                    NUMBER OF ENCLOSED GUN CLEANERS
                     AND SOLVENT USAGE REPRESENTED
                         BY BASELINE AND MACT
Model Plant
Size
Small
Medium
Large
Number of Enclosed
Gun Cleaners
Baseline
1
2
3
MACT
4
6
8
Solvent Usage
(gal/yr)
Baseline
4,200
5,700
7,300
MACT
1,040 i
1,560
2,080

-------
Ms. Vickie Boothe
August 25, 1993
Page 3
     The baseline and MACT solvent usages were derived from a
facility that reported solvent consumption declined from 25
gallons per week to 5 gallons per week after the installation of
an enclosed spray gun cleaner.

     Cost information for enclosed spray gun cleaners with a
capacity of 4 spray guns and equipped to handle both waterborne
and solvent-based coatings was obtained from two vendors.  The
average cost of the three models quoted was $2,300.2f3

     Maintenance and utility costs for all quoted models are very
small.  The primary maintenance item is an air-actuated diaphragm
pump.  However, the pump is expected to last over 100,000 3-
minute cycles before replacement.4  Assuming 10 cleaning cycles
per shift, 3 shifts per day, and 250 days per year, this
corresponds to a life expectancy of 13 years.

     Methyl ethyl ketone (MEK) was the most frequently reported
spray gun cleaning solvent in the Section 114 questionnaire
responses and was used as the baseline solvent for the cost
impacts.  The cost of MEK was reported as $4.00 per gallon.5

Baseline Costs

Capital cost of equipment:

Small model plant:  1 enclosed gun cleaner  x $2,300 = $2,300
Medium model plant: 2 enclosed gun cleaners x $2,300 = $4,600
Large model plant:  3 enclosed gun cleaners x $2,300 = $6,900

Annualized cost:

     The annualized costs were calculated by the following
equation:


                 Annualized  Costs  = TCC
     where,

     TCC = Total Capital Cost
     i   = Interest Rate
     n   = Equipment Life  (years)

-------
Ms. Vickie Booths
August 25, 1993
Page 4
Using the total capital cost of the enclosed spray gun cleaners
presented above, an interest rate of 7 percent, and an equipment
life of 13 years, the annualized costs by model plant are:

     Small model plant:   $270/yr
     Medium model plant:  $550/yr
     Large model plant:   $830/yr

Solvent cost:

Small model plant:  4,200 gal/yr x $4.00/gal = $16,800/yr

Medium model plant: 5,700 gal/yr x $4.00/gal = $22,800/yr

Large model plant:  7,300 gal/yr x $4.00/gal = $29,200/yr


Solvent Disposal Costs

     Based on information provided by Lockheed Missiles and Space
Company, Inc., Sunnyvale, California, approximately 98 percent of
the original solvent usage must be disposed.6  Disposal costs
were quoted as $1.50/gallon.7

Small model plant:  4,200 gal/yr x 0.98 x $1.50/gal =  $6,170/yr

Medium model plant: 5,700 gal/yr x 0.98 x $1.50/gal =  $8,380/yr

Large model plant:  7,300 gal/yr x 0.98 x $1.50/gal = $10,730/yr


Total Baseline Costs

Total baseline costs = Solvent costs + Annualized costs + Solvent
disposal costs

Small model plant:   $16,800/yr + $270/yr +  $6,170/yr = $23,240/yr

Medium model plant:  $22/800/yr -f $550/yr +  $8,380/yr = $31,730/yr

Large model plant:   $29,200/yr + $830/yr + $10,730/yr = $40,760/yr


MACT COSTS

     As stated previously, MACT floor specifies enclosed spray
gun cleaners, cabinet type gun cleaners, vat cleaning using
unanomized spray, and atomizad spray into a wasna container

-------
Ms. Vickie Boothe
August 25, 1993
Page 5
fitted with a capture device designed to capture atomized solvent
emissions.  For the purpose of the impact analysis, it will be
assumed that each facility uses enclosed spray gun cleaners.

Capital cost of equipment:

Small model plant:   3 enclosed gun cleaners x $2,300 = $ 6,900

Medium model plant:  4 enclosed gun cleaners x $2,300 = $ 9,200

Large model plant:   5 enclosed gun cleaners x $2,300 = $11,500


Annualized cost  (see annualized cost for baseline):

     Small model plant:   $830/yr
     Medium model plant:  $l,100/yr
     Large model plant:   $l,380/yr

Solvent cost:

Small model plant:  1,040 gal/yr x $4.00/gal - $4,160/yr

Medium model plant: 1,560 gal/yr x $4.00/gal = $6,240/yr

Large model plant:  2,080 gal/yr x $4.00/gal = $8,320/yr


Spent Solvent Disposal Costs

     As explained in the baseline spent solvent disposal section,
approximately 98 percent of the original solvent usage must be
disposed  of at the same disposal cost.

Small model plant:  1,040 gal/yr x 0.98 x $1.50/gal = $l,530/yr

Medium model plant: 1,560 gal/yr x 0.98 x $1.50/gal = $2,290/yr

Large model plant:  2,080 gal/yr x 0.98 x $1.50/gal = $3,060/yr


Total MACT Costs

Total MACT costs = Solvent cost + Annualized costs + Solvent
Disposal  costs

-------
Ms. Vickie Boothe
August 25, 1993
Page 6
Small model plant:  $4/160/yr + $830/yr + $l/530/yr  = $6,520/yr

Medium model plant:  $6,240/yr + $l,100/yr + $2,290/yr  = $9,630/yr

Large model plant:  $8,320/yr + $l,380/yr + $3,060/yr  = $12,760/yr


Cost Impact

The total cost impact of implementing the MACT standard is equal
to the total MACT costs minus the total baseline cost.

Small model plant:    $6,520/yr - $23,240/yr = ($16,720/yr)

Medium model plant:   $9,630/yr - $31,730/yr = ($22,100/yr)

Large model plant:   $12,760/yr - $40,760/yr = ($28,000/yr)


References

1. Trip Report -  Naval Aviation Depot  in Alameda,  California,  on
   February  28, 1992.

2. Letter.   Sabol, Mick, James McGraw, Inc., to Kathy  Feser,
   PES.   January  26, 1993.   Pricing  and specifications of
   enclosed  spray gun cleaners.

3. Letter.   Lowe,  Ronnie, Air Power, Inc., to Kathy  Feser, PES.
   January 26, 1993.  Pricing and specifications of  enclosed
   spray  gun cleaners.

4. Telephone Report.  K. Feser, PES, and W. Lindow,  Herkules
   Equipment Corporation, on February  16, 1993.

5. Section 114 Questionnaire Response  from Boeing  Aerospace and
   Defense Facility in Oak  Ridge, Tennessee.

6. Letter.   Kurucz, Kraig,  Lockheed  Missiles and Space Company,
   Inc.,  to  David Hendricks, PES.  May 17, 1993.   Information  on
   enclosed  gun cleaner alternatives.

7. Letter.   Taylor, Carole,  Northrop Corp., Aircraft Division,
   to  David  Hendricks, PES.  February  22, 1993.  Usage and cost
   of  gun cleaning solvent.

-------
                           MEMORANDUM
TO:       Vickie Boothe
          US EPA:ESD

FROM:     David Hendricks
          Pacific Environmental Services, Inc. (PES)

DATE:     August 25, 1993
          L:\N019

SUBJECT:  MACT Cost Impact Analysis for Primers and Topcoats
     The purpose of this memo is to calculate and compare
baseline and MACT cost impacts for low HAP primers and topcoats
and for the coating application equipment for these primers and
topcoats.  Baseline coatings consist of military and commercial
primers and topcoats as reported in the Section 114 questionnaire
responses.  Baseline application methods consist of a mix of
conventional, HVLP, and electrostatic spray guns as reported in
the Section 114 questionnaire responses.  The MACT floor
specifies product substitutions to reduce the HAP content of the
coatings.  For the purpose of the impact analysis, it will be
assumed that each facility replaces all of their conventional
primers and topcoats with reduced HAP content primers and
topcoats rather than controlling emissions through abatement.
The MACT floor also specifies high transfer efficiency methods
for primer and topcoat application (e.g., flow coat, roll coat,
dip coat, electrostatic, or HVLP).  For the purpose of the impact
analysis, it will be assumed that all model plants replace their
conventional spray guns used to apply primers and topcoats with
HVLP spray guns.  Due to the difference in coating usage between
commercial and military model plants, the coating substitution
cost impacts will also be different.   Consequently, the impact
analysis was completed for commercial and military model plants
as well as for different size model plants.  There is no
difference in coating application methods for commercial and
military model plants and the calculations will be assumed the
same for either model plant.  There is no difference between OEM
and rework facilities.

-------
Ms. Vickie Boothe
August 25, 1993
Page 2
     Table 1 summarizes the costs.  As presented in Table 1,
implementation of MACT coating substitutions is expected to
result in annual savings of $36,830 for small commercial model
plants, $67,350 for medium commercial model plants, and $520,600
for large commercial model plants.  Additionally, the
implementation of MACT application methods is expected to result
in annual savings of $8,680 for small military model plants,
$12,450 for medium military model plants, and $90,830 for large
military model plants.  The assumptions and calculations used in
deriving these costs are detailed below.  Baseline and MACT for
coating substitutions and application methods are analyzed
separately.  The total cost impacts are then calculated.


BASELINE FOR COATING SUBSTITUTIONS

Coating Usage

     Baseline coatings consist of military and commercial primers
and topcoats as reported in the Section 114 questionnaire
responses.  The average annual baseline usage of commercial and
military primers and topcoats is presented in Table 2.

     The cost of primers and topcoats was provided by three
coating manufacturers.1'2'3  Average costs per gallon are presented
in Table 3 for baseline and MACT coatings.

     Baseline costs are calculated by multiplying annual baseline
coating usage by cost per gallon.  The result is cost per year.
Sample cost calculations for a large, commercial primer operation
are presented below.  The calculations for all other coating
categories and model plants were done in a similar manner.
Baseline costs are presented in Table 4.

Baseline Primer Cost = 18,000 gal/yr x $23/gal  = $414,000/yr

Coating Labor

     Based on an article in Industrial Finishing, one aerospace
manufacturer uses 200 gallons of paint and 1,250 labor hours to
paint a wide body aircraft, and 125 gallons of paint and 500
labor hours for a narrow body aircraft.4  A large portion of the
labor hours, however, are for masking and drying operations that
will occur regardless of the spray guns used.  According to the
same article, 67 percent of the labor hours are spent during
drying, and 8 percent for masking.  These two operations account

-------







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-------
Ms. Vickie Boothe
August 25, 1993
Page 4
                             TABLE 2
              BASELINE AVERAGE ANNUAL COATING USAGE
                       BY MODEL PLANT SIZE8
Model
Plant
Size
Small
Medium
Large
Commercial Usage
(gal)
Primers
500
2,100
18,000
Topcoats
500
2,000
17,900
Military Usage
(gal)
Primers
170
710
6,100
Topcoats
110
420
3,800
           aSource:  Section 114 questionnaire  responses,
                             TABLE 3
       BASELINE AND MACT PRIMER AND TOPCOAT  COATING  COSTS8
Coating
Category
Primers
Topcoats
Baseline
Commercial
($/Gallon)
23
48
Military
($/Gallon)
23
59
MACT
Commercial
($/Gallon)
32
55
Military
($/Gallon)
39
74
  a  Source:   Section 114  questionnaire responses and vendor
    information.

                             TABLE 4
           ANNUAL BASELINE COSTS FOR AEROSPACE COATINGS
Model
Plant
Size
Small
Medium
Large
Commercial Costs
($)
Primers
11,500
48,300
414,000
Topcoats
24,000
96,000
859,200
Military Costs
($)
Primers
3,910
16,330
140,300
Topcoats
6,490
24,780
224,200

-------
Ms. Vickie Boothe
August 25, 1993
Page 5
for 75 percent of the labor hours, leaving 25 percent for the
actual application of the paint.  Thus, 313 hours are used to
apply 200 gallons on the wide body aircraft, and 125 hours to
apply 125 gallons on the narrow body aircraft.  This equates to
1.6 hours/gallon and 1.0 hours/gallon for applying paint on wide
body and narrow body aircraft, respectively.  An average of 1.3
hours/gallon will be used for the cost analysis.  The baseline
labor hours are presented in Table 5 and are the values in Table
2 multiplied by 1.3 hours/gallon.  Using $40/labor hour as
developed in the MACT cost analysis for aircraft depainting,5 the
baseline labor costs by model plant are presented in Table 6 and
are the values in Table 5 multiplied by $40/hour.

     The total baseline costs for coating substitutions are
presented in Table 7.  These values were calculated by adding the
costs in Table 4 and Table 6 and then adding the primer and
topcoat values for each size model plant.


MACT COSTS FOR COATING SUBSTITUTIONS

Coating Usage Savings

     The MACT floor specifies product substitutions to reduce the
HAP content of the coatings.  The cost per gallon of MACT floor
primers and topcoats was calculated from data provided by three
coating manufacturers as referenced in the baseline coating
substitution section.  The costs for the coatings that would be
allowed under the MACT floor were averaged for primers and
topcoats.  The MACT floor cost per gallon is presented in Table
3.  MACT floor coating usage values were calculated in the
environmental impact analysis for primers and topcoats6 and are
presented in Table 8.  The MACT floor costs were calculated by
multiplying the cost per gallon from Table 3 by the annual usage
from Table 8.  These values are shown in Table 9.

Labor Savings

     The implementation of MACT will reduce labor required to
paint due to the reduced number of gallons to be applied.
Because HVLP spray guns transfer coatings more efficiently than
conventional spray guns, fewer gallons of coating need to be
applied to achieve th-e same coating thickness.  As a result,
there is an equivalent reduction in the labor hours needed to
apply the coatings.  MACT labor hour data are presented in Table
10 and are the values in Table 8 multiplied by 1.3 hours/gallon
(see baseline labor calculations).

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Ms. Vickie Boothe
August 25, 1993
Page 6
                             TABLE 5
                   ANNUAL BASELINE LABOR HOURS
                       BY MODEL PLANT SIZE
Model Plant
Size
Small
Medium
Large
Labor Hours
(hours)
Commercial
Primers
650
2,730
23,400
Topcoats
650
2,600
23,270
Military
Primers
220
920
7,930
Topcoats
140
550
4,940
                             TABLE 6
                 ANNUAL BASELINE LABOR HOUR COSTS
                       BY MODEL PLANT  SIZE
Model Plant
Size
Small
Medium
Large
Labor Hour Costs
($)
Commercial
Primers
26,000
109,200
936,000
Topcoats
26,000
104,000
930,800
Military
Primers
8,800
36,800
317,200
Topcoats
5,600
22,000
197,600
                             TABLE  7
  ANNUAL BASELINE TOTAL COST FOR COATING SUBSTITUTIONS AND LABOR
Model Plant
Size
Small
Medium
Large
Total Cost
($)
Commercial
87,500
357,500
3, 140,000
Military
24,800
99,910
879,300

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Ms. Vickie Booths
August 25, 1993
Page 7
                             TABLE  8
                ANNUAL MACT AVERAGE COATING USAGE
             (AFTER IMPLEMENTATION OF HVLP  SPRAY  GUNS
                    AND PRODUCT SUBSTITUTIONS)
                       BY MODEL  PLANT SIZE
Model
Plant
Size
Small
Medium
Large
Commercial Usage
(gal)
Primers
275
1,640
14,490
Topcoats
250
1,420
13,100
Military Usage
(gal)
Primers
100
610
5,390
Topcoats
50
250
2,360
                             TABLE  9
             ANNUAL MACT COSTS FOR AEROSPACE COATINGS
Model
Plant
Size
Small
Medium
Large
Commercial Costs
($)
Primers
8,800
52,480
463,680
Topcoats
13,750
78,100
720,500
Military Costs
($)
Primers
3,900
23,790
210,210
Topcoats
3,700
18,500
174,640
                             TABLE 10
                     ANNUAL MACT  LABOR HOURS
                        BY MODEL PLANT SIZE
Model Plant
Size
Small
Medium
Large
Labor Hours
(hours)
Commercial
Primers
360
2,130
18,840
Topcoats
330
1,850
17,030
Military
Primers
130
790
7,010
Topcoats
70
330
3,070

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Ms. Vickie Boothe
August 25, 1993
Page 8
     Using $4O/labor hour rate as used for baseline, the labor
costs by model plant are presented in Table 11 and are the values
in Table 10 multiplied by $40/hour.

     The total MACT floor costs for coating substitutions and
labor are presented in Table 12.  The cost impacts were
calculated by adding the costs in Table 9 and Table 11 and then
adding the primer and topcoat values for each size model plant.


BASELINE FOR APPLICATION METHODS

     Baseline application methods consist of a mix of
conventional, HVLP, and electrostatic spray guns as reported in
the Section 114 questionnaire responses.  The capital costs of
conventional, HVLP, and electrostatic spray guns including spare
parts are $285, $650, and $3,500, respectively.7'8  Maintenance
cost are higher for HVLP and electrostatic spray guns than
conventional, but this could not be quantified.  Utility costs
are higher for electrostatic spray guns, but this could not be
quantified also.  There are no known installation costs for any
of the guns.  The baseline coating application equipment has been
defined as follows:

     Small Model Plants
          Spray guns   - 30  conventional
                          6  HVLP
                          0  electrostatic

     Medium Model Plants
          Spray guns   - 20  conventional
                         50  HVLP
                         10  electrostatic

     Large Model Plants
          Spray guns   - 24  conventional
                         80  HVLP
                         20  electrostatic

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Ms. Vickie Boothe
August 25, 1993
Page 9
                             TABLE 11
                   ANNUAL MACT LABOR HOUR COSTS
                       BY MODEL PLANT SIZE
Model Plant
Size
Small
Medium
Large
Labor Hour Costs
($)
Commercial
Primers
14,400
85,200
753,600
Topcoats
13,200
74,000
681,200
Military
Primers
5,200
31,600
280,400
Topcoats
2,800
13,200
122,800
                             TABLE 12
    ANNUAL TOTAL MACT COST FOR COATING SUBSTITUTION AND LABOR
                       BY MODEL PLANT SIZE
Model Plant
Size
Small
Medium
Large
Total Cost
($)
Commercial
50,150
289,780
2,618,980
Military
15,600
87,090
788,050

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Ms. Vickie  Boothe
August 25,  1993
Page 10
Baseline Spray Gun Cost
Small Model  Plants:
Medium Model  Plants:
Large Model  Plants:
30 spray guns x  $285/spray gun  = $ 8,550
 6 spray guns x  $650/spray gun  =   3.900
         Total                      12,450

 20 spray guns x $285/spray gun  = $ 5,700
 50 spray guns x $650/spray gun  =  32,500
 10 spray guns x $3,500/spray gun=  35,000
         Total                       73,200

24 spray guns x  $285/spray gun  = $  6,840
80 spray guns x  $650/spray gun  =   52,000
20 spray guns x  $3,500/spray gun=   70.000
         Total                      128,840
Annualized  costs were calculated by the  following equation:
                  Annualized Costs =  TCC
                                         i (!+/)"
                                         (1+7)" - 1.
     where,

     TCC =  Total Capital Cost
     i   =  Interest Rate
     n   =  Equipment Life (years)

Using the total capital cost presented above,  an interest rate of
7 percent,  and an equipment life of 10 years,9 the annualized
costs by model plant for baseline are:

     Small  model plant:  $1,770
     Medium model plant: $10,420
     Large  model plant:  $18,340
MACT COSTS  FOR APPLICATION METHODS

     As noted above,  MACT consists of replacing all conventional
spray guns  used to apply primers and topcoats with HVLP spray
guns.  Costs need to be developed, therefore,  for the replacement
HVLP spray  guns.   The capital cost imposed  by the MACT floor is
the cost  of replacing the percentage of  conventional spray guns
11 *•<• f^f3 "fr™ ^> ^S •w^v^ 1 ^ T mv* i "w» Q ^*f* ••» v* *^ ^* *"»ivx ^^^^ *» +• f+ T.» ^ ^ !•*  TTTTT T^ /•« v^^»-^ •* y f*~* ^ »•* *••   fTTV% *-*
i4.owv^t w\J t*^/^j j. jr  ¥*• J-^11*—•*• *z» UII^A u.v^^^r^^/u.v^h? w j. w.i.1  A! v J_ii" o^j. CL-J  ^ \Atna •  JL±I*^
percsntage  of ccnvenricnai spray juns used  to apply primers and

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Ms. Vickie Booths
August 25, 1993
Page 11
topcoats is assumed to be equivalent to the percentage of the
total overall coating usage represented by the usage of primers
and topcoats by model plant.  Based on the coating usage reported
in the Section 114 questionnaire responses, primers accounted for
approximately 16 percent of the total coating usage and topcoats
accounted for approximately 17 percent of the total coating
usage.

Small Model Plants:  30 spray guns x (16% + 17%) = 10
Medium Model Plants: 20 spray guns x (16% + 17%) =  7
Large Model Plants:  24 spray guns x (16% + 17%) =  8


Therefore, the MACT coating application equipment is defined as
follows:

     Small Model Plants
          Spray guns   - 20  conventional
                         16  HVLP
                          0  electrostatic

     Medium Model Plants
          Spray guns   - 13  conventional
                         57  HVLP
                         10  electrostatic

     Large Model Plants
          Spray guns   - 16  conventional
                         88  HVLP
                         20  electrostatic
MACT Spray Gun Cost
Small Model Plants:
Medium Model Plants:
Large Model Plants:
20 spray guns x $285/spray gun = $ 5,700
16 spray guns x $650/spray gun =  10.400
         Total                    16,100

 13 spray guns x $285/spray gun   = $ 3,710
 57 spray guns x $650/spray gun   =  37,050
 10 spray guns x $3,500/spray gun =  35,OOP
         Total                       75,760

16 spray guns x $285/spray gun   = $  4,560
88 spray guns x $650/spray gun   =   57,200
20 spray guns x $3,500/spray gun =   70,OOP
         Total                      131,760

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Ms. Vickie Boothe
August 25, 1993
Page 12
Annualized costs for MACT were calculated using the equation from
the baseline section.

     Small model plant:  $2,290
     Medium model plant: $10,790
     Large model plant:  $18,760

Total Baseline Costs

     The total baseline costs are calculated by adding the costs
in Table 7 with the baseline annualized equipment costs.  These
values are presented in Table 13.

                             TABLE 13
                       TOTAL BASELINE  COSTS
                       BY MODEL PLANT SIZE
Model Plant
Size
Small
Medium
Large
Total Cost
($)
Commercial
89,270
367,920
3,158,340
Military
26,570
110,330
897,640
Total MACT Costs

     The total MACT costs are calculated by adding the costs  in
Table 12 with the MACT annualized equipment costs.  These values
are presented in Table 14.

                             TABLE 14
                         TOTAL MACT COSTS
                       BY MODEL PLANT SIZE
Model Plant
Size
Small
Medium
Large
Total Cost
($)
Commercial
52,480
300,570
2,637,740
Military
17,890
97,880
806,810

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Ms. Vickie Boothe
August 25, 1993
Page 13
Cost Impact

     The MACT cost impacts were calculated by subtracting the
costs that would have occurred under baseline (Table 13) from the
costs that will result from implementation of MACT (Table 14).
These values are presented in Table 15.

                             TABLE 15
                        TOTAL COST IMPACT
                       BY MODEL PLANT SIZE8
Model Plant
Size
Small
Medium
Large
Total Cost
($)
Commercial
(36,830)
(67,350)
(520,600)
Military
(8,680)
(12,450)
(90,830)
                    Values in parentheses represent a cost
                    savings to the model plant.
References

 1.  Letter.  K. McKown, Akzo, to J. Hamilton, PES.  March 16,
     1993.  Coating cost data.

 2.  Letter.  M. H. Allen, Crown Metro, to J. Hamilton, PES.
     March 26, 1993.  Coating cost data. Classified as
     proprietary information.

 3.  Letter.  R. Martin, Courtaulds Aerospace, to J. Hamilton,
     PES.  March 12, 1993.  Coating cost data.  Classified as
     proprietary information.

 4.  "Painting Technology Soars at Boeing," Industrial Finishing,
     September 1991. pp. 18-21.

 5.  Memorandum.  D. Hendricks, PES, to V. Boothe, EPA:ESD.
     August 25, 1993.  MACT cost analysis for aircraft
     depainting.

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Ms. Vickie Boothe
August 25, 1993
Page 14
 6.  Memorandum.  D. Hendricks, PES, to V. Boothe, EPA:BSD.
     August 25, 1993.  MACT environmental impact analysis for
     primers and topcoats.

 7.  Section 114 Questionnaire Responses from McDonnell Douglas
     Corporation in St. Louis, Missouri; TRW Space and Defense
     Space Park Facility in Redondo Beach, California; Trans
     World Airlines Ground Operations Center in Kansas City,
     Missouri; Naval Aviation Depot in Alameda, California;
     Martin Marietta Sand Lake Road Facility in Orlando, Florida;
     Lockheed Missiles and Space Company Sunnyvale Facility in
     Sunnyvale, California.

 8.  Telephone Report.  G. LaFlam, PES, and L. Simonson,
     DeVilbiss Ransburg, on September 16, 1992.

 9.  Industrial Surface Coating:  Appliances - Background
     Information for Proposed Standards. EPA-450/3-80-037a,
     November 1980, p. 3-31.

-------
                           MEMORANDUM

TO:       VICKIE SOOTHE
          US EPA:ESD

FROM:     DAVID HENDRICKS
          PACIFIC ENVIRONMENTAL SERVICES, INC.

DATE:     February 15, 1994

SUBJECT:  NATIONWIDE MACT COST ANALYSIS FOR THE CONTROL OF PRIMER
          AND TOPCOAT INORGANIC EMISSIONS, DEPAINTING INORGANIC
          EMISSIONS, WASTEWATER EMISSIONS, STORAGE TANK
          EMISSIONS, AND WASTE EMISSIONS
A.  PRIMER AND TOPCOAT INORGANIC HAP EMISSIONS

     The MACT floor level of control specifies that all primer
and topcoat operations must be performed within a spray booth or
hangar with an active ventilation system.  The exhaust air stream
must pass through either dry filters or a waterwash system.  The
cost analysis examines the following two situations:   (1)
facilities that do not currently paint within a booth or hangar
and must construct these facilities, and (2) facilities that
paint within a booth or hangar but have no dry filters or
waterwash.

     Table 1 summarizes the MACT cost impacts.  The total annual
MACT implementation costs are $2,287,310, which includes
annualized costs for adding new spray booths and modifying
existing spray booths and hangars, and annual operating costs for
dry filter replacement.

                             TABLE 1
          ANNUAL COSTS TO IMPLEMENT PRIMER AND TOPCOAT
                 INORGANIC HAP EMISSION CONTROLS
Item
1.
2.
3.
4.
Annualized Costs for Spray Booths
Annualized costs for Modifying
Existing Spray Booths
Annual Operating Costs
Total MACT Implementation Cost
Cost (1993 Dollars)
$978,230
452,990
856,160
2,287,380

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Ms. Vickie Booths
February 15, 1994
Page 2
Baseline

     For the purpose of the cost analysis, it was assumed that 5
percent of small facilities do not perform primer and topcoat
operations within a booth or hangar, and that all medium and
large facilities perform all of these operations within a booth
or hangar.  Additionally, it was assumed that 10 percent of
small, 2 percent of medium, and 1 percent of large facilities
perform primer and topcoat operations within a booth or hangar
with no dry filters or waterwash.  It is further assumed that
these booths and hangars already have a ventilation system in
place.

     No baseline costs are incurred in either situation.  Those
facilities not painting within a booth or hangar have no baseline
capital costs for booths or hangars, nor do they have baseline
operating costs associated with dry filters.  Those facilities
that have booths or hangars without dry filters or waterwash have
already incurred the capital cost of these structures; therefore,
the capital costs will not be included in the baseline.
Additionally, since there are no filtering systems being used in
these existing booths and hangars, no operating costs are
incurred.

MACT Floor

     Table 2 presents the total number of facilities nationwide
by size, number of each size of facility currently not painting
within a booth or hangar, and number of facilities currently
painting within a booth or hangar with no dry filters or
waterwash.
Facility
Size
Small
Medium
Large
Total
Number of
Facilities
1318
1533
18
Number of
Facilities Without
Booths or Hangars
66
(5% of total)
0
0
Number of Facilities
Without Dry Filters
or Waterwash
132
(10% of total)
31
(2% of total)
1
(1% of total)
     Based on Section 114 questionnaire responses and
observations made during site visits, Table 3 presents the number
and size of spray booths and hangars for each facility size.  For

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Ms. Vickie Soothe
February 15, 1994
Page 3
the small facilities with no spray booths, all five 10' x 10'
booths would have to be added, as well as one 25' x 25' booth.
For the facilities that already have the booths or hangars in
place, dry filters and the associated framework needed for
mounting the filters would have to be added.

                             TABLE 3

  DISTRIBUTION AND SIZE OF SPRAY BOOTHS/HANGARS  BY FACILITY  SIZE
Facility
Size
Small
Medium
Large
Number of Booths/Hangars
10' x 10'
Booth
5
7
10
25' X 25'
Booth
1
2
4
150'X 200'X 75'
Hangar
0
2
3
     For the purpose of the cost analysis, the worst case was
used where all of the new spray booths  (for the small facilities
that currently have no booths) are equipped with waterwash
systems rather than dry filters.  The waterwash booths are
approximately 50-100 percent more expensive than the dry filter
booths.  One vendor quoted the cost of a waterwash booth
measuring 10' x 10' x 7' deep to be $15,000, and the cost of a
waterwash booth measuring 18' x 16' x 64' deep to be $60,000.1
These cost were assumed to approximate the cost of the 10' x 10'
and 25' x 25' booths presented in Table 3.  The capital cost
associated with the 66 small facilities that currently have no
spray booths is then:

     [($15,000/booth x 5 booths) + ($60,000/booth x 1 booth)]
     x 66 facilities = $8,910,000

Amortizing this cost over 15 years at an interest rate of 7
percent, the annualized cost is $978,230.

     The operating costs associated with waterwash booths is
assumed to be negligible since these booths require no
replacement filters or continuous labor requirements.

     The facilities that must upgrade existing booths or hangars
were assumed to add dry filters rather than waterwash.  For the
number of filters per spray booth or hangar, it was assumed that
the entire rear wall of both the small and large booths was
comprised of filters.  For the hangar, it was assumed that 20

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Ms. Vickie Booths
February 15, 1994
Page 4
percent of the area of the rear wall was comprised of filters.
The size of all filters was taken to be 20" x 20", as this is a
standard size for the industry.  Table 4 present the number of
filters per booth or hangar.

                             TABLE 4

      NUMBER OF 20" X 20" FILTERS PER SPRAY BOOTH OR HANGAR
Booth/Hangar Size
10' x 10'
25' x 25'
ISO7 X 200' X 75'
Number of Filters
36
225
807
     In order to modify existing booths and hangars for the dry
filters, a one time cost for a framework assembly to hold the
filters in place will be incurred.  One vendor quoted a cost of
$32 per filter (20" x 20") for the framework.2  The total capital
cost for this framework by facility size is then:

Small Facilities

     10' x 10' Booth
     36 filters/booth x 5 booths/facility x $32/filter
     x 132 facilities = $760,320

     25' x 25' Booth
     225 filters/booth x 1 booth/facility x $32/filter
     x 132 facilities = $950,400

     Total capital costs = $760,320 + $950,400 - $1,710,720

Medium Facilities

     10' x 10' Booth
     36 filters/booth x 7 booths/facility x $32/filter
     x 31 facilities = $249,980

     25' x 25' Booth
     225 filters/booth x 2 booths/facility x  $32/filter
     x 31 facilities = $446,400

     150' x 200' x 75' Hangar
     807 filters/hangar x 2 hangars/facility  x $32/facility
     x 31 facilities = $1.601,090

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Ms. Vickie Soothe
February 15, 1994
Page 5


     Total capital costs = $249,980 + $446,400 + $1,601,090
                         » $2,297,470

Large Facilities

     10* x 10/ Booth
     36 filters/booth x 10 booths/facility x $32/filter
     x 1 facility - $11,520

     25' x 25' Booth
     225 filters/booth x 4 booths/facility x $32/filter
     x 1 facility = $28,800

     150/ x 200/ x 75' Hangar
     807 filters/hangar x 3 hangars/facility x $32/filter
     x 1 facility = $77,470

     Total capital costs = $11,520 + $28,800 + $77,470 = $117,790

     Amortizing this cost over  15 years at an interest rate of 7
percent, the annual cost by model plant size is:

     Small - $187,820
     Medium - $252,240
     Large - $12,930

Total annualized capital costs  are then the sum of  the individual
annualized capital costs for each size model plant,  or $452,990.

     Annual operating costs are associated with replacing  the dry
filters.  It was assumed that all filters would be  changed four
times per year.  One vendor quoted a price of $1.66 for a  typical
20" x 20" filter.3  Annual operating costs are then:

Small Facility

     10/ x 10• Booth
     36 filters/booth x 5 booths/filter x $1.66/filter
     x 132 facilities x 4 = $157,770

     25' X 25 * Booth
     225 filters/booth x 1 booth/facility x $1.66/filter
     x 132 facilities x 4 - $197,210

     Total operating costs = $354,980

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Ms. Vickie Boothe
February 15, 1994
Page 6


Medium Facility

     10• x 10/ Booth
     36 filters/booth x 7 booths/facility x $1.66/filter
     x 31 facilities x 4 = $51,870

     25• X 25/ Booth
     225 filters/booth x 2 booths/facility x $1.66/filter
     x 31 facilities x 4 = $92,630

     150' x 200' x 75' Hanaar
     807 filters/hangar x 2 hangars/facility x $1.66/filter
     x 31 facilities x 4 = $332,230

     Total operating costs = $476,730

Large Facility

     10' x 10' Booth
     36 filters/booth x 10 booths/facility x $1.66/filter
     x 1 facility x 4 = $2,390

     25/ x 25' Booth
     225 filters/booth x 4 booths/facility x $1.66/filter
     x 1 facility x 4 = $5,980

     150* x 200' x 75' Hanaar
     807 filters/hangar x 3 hangars/facility x $1.66/filter
     x 1 facility x 4 = $16,080

     Total operating costs = $24,450

Total operating costs are then the sum of the costs  for each size
model plant, or $856,160.

     Total MACT implementation costs are the sum of  the
annualized capital costs plus the annual operating costs:

     MACT implementation costs = $978,230 + $452,990 + $856,160
                               = $2,287,380

B.  DEPAINTING INORGANIC HAP EMISSIONS

     The MACT floor level of control specifies that  inorganic HAP
emissions be controlled by 99 percent.  This can be  achieved
through the use of a baghouse or particulate filters.  This cost
analysis examines the conversion from low efficiency particulate
filters to high efficiency particulate filters that  meet the MACT

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Ms. Vickie Boothe
February 15, 1994
Page 7
floor level of control.  Table 5 summarizes the baseline and MACT
costs.  The total annual MACT implementation costs are $116,580.

                             TABLE 5
              ANNUAL COSTS TO IMPLEMENT DEPAINTING
                 INORGANIC HAP EMISSION CONTROLS
Item
1. Baseline Annual Operating
Costs
2 . MACT Annual Operating
Costs
3 . Cost Impact
(line 2 - line 1)
Model Plant
Small
$3,590
3,950
360
Medium
$13,400
14,770
1,370
Large
$13,400
14,770
1,370
     It is not reasonable to assume that all commercial and
military rework facilities (a total of 2,026 facilities) depaint
the outer surface of aerospace vehicles.  Therefore, it was
assumed that only 5 percent of the small and medium facilities
and all of the large facilities perform outer surface depainting
(see Table 6).

                             TABLE 6
       NUMBER OF DEPAINTING FACILITIES BY MODEL PLANT SIZE
Model Plant
Size
Small
Medium
Large
Number of
Facilities
27
73
5
Baseline

     Baseline has been defined as depainting fully painted
aircraft with plastic media and using particulate filters with a
control efficiency of 95 percent.  Based on Section 114
questionnaire responses and observations made during site visits,
it was assumed that small facilities would perform the blasting
operation in a 100' x 100 ' x 30' high hangar, and medium and
large facilities would use a 150' x 200-' x 75-' high hangar.
                                                             It

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Ms. Vickie Booths
February 15, 1994
Page 8


was also assumed that the small size hangar has 216 filters (20"
x 20"), the large size hangar has 807 filters (20" x 20"), and
that these filters are changed 10 times per year.

     One vendor quoted a price of $1.66 for a typical low
efficiency 20" x 20" filter.4  Based on the number of filters  for
each size hangar and the number of filter changes per year
presented above, the baseline annual operating costs per model
plant are:

     Small rework facility:  216 filters x $1.66/filter x 10
                             = $3,590/yr
     Medium rework facility:  807 filters x $1.66/filter x 10
                              = $13,400/yr
     Large rework facility:  807 filters x $1.66/filter x 10
                             = $13,400/yr
MACT Floor

     The MACT floor can be achieved through the use of high
efficiency particulate filters.  One vendor quoted a price of
$1.83 for a typical high efficiency 20" x 20" filter.5  Annual
operating costs for the MACT floor level of control are then:

     Small rework facility: "216 filters x $1.83/filter x 10
                             - $3,950/yr
     Medium rework facility:  807 filters x $1.83/filter x 10
                              = $14,770/yr
     Large rework facility:  807 filters x $1.83/filter x 10
                             = $14,770/yr

     The MACT implementation costs are then the MACT costs minus
the baseline costs:

     Small rework facility:  $3,950/yr - $3,590/yr = $360/yr
     Medium rework facility:  $14,770/yr - $13,400/yr = $l,370/yr
     Large rework facility:  $14,770/yr - $13,400/yr = $l,370/yr

     Nationwide costs are then the MACT implementation costs
multiplied by the total number of facilities:

     Small rework facility:  $360/yr x 27 = $9,720/yr
     Medium rework facility:  $l,370/yr x 73 = $100,010/yr
     Large rework facility:  $l,370/yr x 5 = $6,850/yr

     Total nationwide costs = $9,720/yr + $100,010/yr + $6,850/yr
                            = $116,580

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Ms. Vickie Boothe
February 15, 1994
Page 9


C.  WASTEWATER

MACT floor is no control; therefore, no cost incurred.

D.  STORAGE TANKS

MACT floor is no control; therefore, no cost incurred.

E.  WASTE

     100 percent of the reporting facilities are already
performing housekeeping measure; therefore, no additional costs
will be incurred.

REFERENCES

1.   Telephone Report.  K. Feser, PES, and Sales Representative,
     JBI, on November 5, 1993.

2.   Telephone Report.  K. Feser, PES, and J. Hovekamp, Airguard
     Industries, Inc., on November  2, 1993.

3.   Reference 2.

4.   Reference 2.

5.   Reference 2.

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                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
 REPORT NO.
:PA-453/R-94-036a
            3. RECIPIENT'S ACCESSION NO.
.TITLE AND SUBTITLE  National  Emission Standards  for
Hazardous Air Pollutants for Source Categories:
Aerospace Manufacturing and  Rework
            5. REPORT DATE
                   May 1994
            6. PERFORMING ORGANIZATION CODE
 AUTHOR(S)
                                                            8. PERFORMING ORGANIZATION REPORT NO.
. PERFORMING ORGANIZATION NAME AND ADDRESS
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina   27711
            10. PROGRAM ELEMENT NO.
            11. CONTRACT/GRANT NO.

                 68D10116
2. SPONSORING AGENCY NAME AND ADDRESS
Director,  Office of Air  Quality Planning  and Standards
Office  of  Air and Radiation
U.S.  Environmental Protection Agency
Research Triangle Park,  North Carolina  27711
            13. TYPE OF REPORT AND PERIOD COVERED
            14. SPONSORING AGENCY CODE
                     EPA/200/04
5. SUPPLEMENTARY NOTES
6. ABSTRACT
A rule  is being proposed  for the regulation of emissions  of hazardous air  pollutants
(HAP) from aerospace manufacturing and  rework processes under the authority of sections
112,  114, 116 and 301  of  the Clean Air  Act, as amended in 1990.  This document presents
the background data and  information  that  supports the proposed regulation.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
                                               b.lOENTIFIERS/OPEN ENDED TERMS
                          c.  COSATl Field/Group
Air pollution
Pollution control
Aerospace
Hazardous air pollutant
National impacts
Air pollution control
18. DISTRIBUTION STATEMENT
                                               19. SECURITY CLASS (Tins Report I
                                                                           21. NO. OF PAGES
                                                20. SECURITY CLASS ,' Tins page I
                                                   UNCLASSIFIED
£PA Form 2220-1 (R«v. 4-77)   pRevious EDITION is OBSOLETE

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