EPA-453/R-00-003
Background Information Document
National Emission Standards For
Hazardous Air Pollutants (NESHAP)
for the Wood Building Products
(Surface Coating) Industry
Emission Standards Division
U. S. Environmental Protection Agency
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, NC 27711
May 2001
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Table of Contents
Chapter 1. Introduction 1-1
Overview i.o 1-1
Background 1.1 1-2
Summary of Existing Federal/State/Local Regulations 1.2 1-3
Project History 1.3 1-5
Data Gathering 1.3.1 1-5
Emissions and Control Data 1.3.2 1-9
References 1.4 1-9
Chapter 2. Wood Building Products-Surface Coating Source Category 2-1
Industry Profile 2.0 2-1
Wood Building Products Surface Coating Processes 2.1 2-4
Interior Paneling 2.1.1 2-9
Paper Laminated Paneling 2.1.1.1 2-9
Printed Interior Paneling 2.1.1.2 2-9
Natural Finish Interior Paneling 2.1.1.3 2-10
Exterior Siding 2.1.2 2-12
Doors and Door Skins 2.1.3 2-12
Solid Wood Doors 2.1.3.1 2-13
Hollow Core Doors 2.1.3.2 2-13
Tileboard 2.1.4 2-15
Flooring 2.1.5 2-15
Window Frames and Joinery 2.1.6 2-15
Shutters 2.1.7 2-16
Moulding and Trim 2.1.8 2-16
Coatings 2.2 2-18
Coating Technologies 2.2.1 2-18
Solventborne Coatings 2.2.1.1 2-18
High-Solids Coatings 2.2.1.2 2-18
Waterborne Coatings 2.2.1.3 2-19
Ultraviolet Radiation-Cured (UV-Cured) Coatings 2.2.1.4 2-20
Electron-Beam (EB) Curable Coatings 2.2.1.5 2-21
Characterization of HAP Emissions 2.3 2-21
HAP Emissions 2.3.1 2-21
Organic HAP Emission Sources and Emission Reduction Techniques 2.3.2 2-25
Surface Preparation 2.3.2.1 2-25
Storage Areas 2.3.2.2 2-25
Waste and Wastewater Operations 2.3.2.3 2-26
Mixing Operations 2.3.2.4 2-26
Subcategorization 2.4 '- 2-27
. Subcategory Descriptions 2.4.1 2-28
Doors and Windows 2.4.1.1 2-28
iii
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Table of Contents (continued)
Page
Flooring 2.4.1.2 2-28
Interior Wall Paneling and Tileboard 2.4.1.3 2-29
Other Interior Panels 2.4.1.4 2-29
Exterior Siding, Doorskins, and Miscellaneous 2.4.1.5 2-29
Performance Requirements 2.4.2 2-30
Doors and Windows 2.4.2.1 2-30
Flooring 2.4.2.2 2-31
Interior Wall Paneling and Tileboard 2.4.2.3 2-31
Other Interior Panels 2.4.2.4 2-32
Exterior Siding, Doorskins, and Miscellaneous 2.4.2.5 2-32
Coating Usage 2.4.3 2-33
Doors and Windows 2.4.3.1 2-33
Flooring 2.4.3.2 2-34
Interior Wall Paneling and Tileboard 2.4.3.3 2-34
Other Interior Panels 2.4.3.4 2-35
Exterior Siding, Doorskins, and Miscellaneous 2.4.3.5 2-35
Organic HAP Emissions 2.4.4 2-35
Doors and Windows 2.4.4.1 2-36
Flooring 2.4.4.2 2-36
Interior Wall Paneling and Tileboard 2.4.4.3 2-36
Other Interior Panels 2.4.4.4 2-37
Exterior Siding, Doorskins, and Miscellaneous 2.4.4.5 2-37
Application Equipment 2.4.5 2-37
Doors and Windows 2.4.5.1 2-37
Flooring 2.4.5.2 2-38
Interior Wall Paneling and Tileboard 2.4.5.3 2-38
Other Interior Panels 2.4.5.4 2-38
Exterior Siding, Doorskins, and Miscellaneous 2.4.5.5 2-38
Control Device Applicability 2.4.6 2-38
Doors and Windows 2.4.6.1 2-38
Flooring 2.4.6.2 2-38
Interior Wall Paneling and Tileboard 2.4.6.3 2-38
Other Interior Panels 2.4.6.4 , 2-38
Exterior Siding, Doorskins, and Miscellaneous 2.4.6.5 2-40
Conclusions and Subcategorization Rationale 2.4.7 2-40
Doors and Windows 2.4.7.1 2-40
Flooring 2.4.7.2 2-41
Interior Wall Paneling and Tileboard 2.4.7.3 2-41
Other Interior Panels 2.4.7.4 2-42
Exterior Siding, Doorskins, and Miscellaneous 2.4.7.5 2-43
References 2.5 2-44
IV
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Table of Contents (continued)
Page
Chapter 3. Emission Control Techniques 3-1
Pollution Prevention Techniques 3.1 3-2
Waterborne Coatings 3.1.1 3-3
Radiation-Curable Coatings 3.1.2 3-6
Ultraviolet-Curable Coatings 3.1.2.1 3-7
Electron Beam-Curable Coatings 3.1.2.2 3-8
Applicability of Low- and No-HAP Coatings 3.1.3 3-9
Waterborne Coatings 3.1.3.1 3-9
Ultraviolet-Curable Coatings 3.1.3.2 3-10
Electron Beam-Curable Coatings 3.1.3.3 3-11
Capture Systems 3.2 3-12
Add-On Control Devices 3.3 3-13
Combustion Control Devices 3.3.1 3-14
Thermal Incineration 3.3.1.1 3-14
Catalytic Incineration 3.3.1.2 3-18
Recovery Devices 3.3.2 3-20
Carbon Adsorption 3.3.2.1 3-21
References 3.4 3-27
Chapter 4. Model Plants and Control Options 4-1
Introduction 4.0 4-1
Model Plants 4.1 4-2
Model Plant 1 - Doors and Windows 4.1.1 4-3
Model Plant 2 - Flooring 4.1.2 : 4-3
Model Plant 3 - Interior Wall Paneling and Tileboard 4.1.3 4-4
Model Plant 4 - Other Interior Panels 4.1.4 4-4
Model Plant 5 - Exterior Siding, Doorskins, and Miscellaneous 4.1.5 4-4
Model Plant Parameters 4.2 4-9
Maximum Achievable Control Technology Floors 4.3 4-10
References 4.4 4-12
Chapter 5. Summary of Environmental and Energy Impacts 5-1
Primary Air Impacts 5.1 5-2
Secondary Environmental Impacts 5.2 5-7
Secondary Air Impacts 5.2.1 5-7
Secondary Water Impacts 5.2.2 5-8
Secondary Solid Waste Impacts 5.2.3 5-8
Energy Impacts 5.3 5-8
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Table of Contents (continued)
Page
Chapter 6. Model Plant Control Costs 6-1
" Introduction 6.0 6-1
Cost Estimates Using Low- or no-HAP Coatings 6.1 6-2
Material Costs 6.1.1 6-2
Recordkeeping and Reporting Costs 6.1.2 6-4
Labor Costs 6.1.2.1 6-4
Computer Equipment Costs 6.1.2.2 6-7
Performance Testing Costs for Add-On Control Devices 6.1.3 6-7
Doors and Windows (Model Plant 1) 6.2 6-11
Flooring (Model Plant 2) 6.3 6-12
Interior Wall Paneling and Tileboard (Model Plant 3) 6.4 6-12
Other Interior Panels (Model Plant 4) 6.5 6-12
Exterior Siding, Doorskins and Miscellaneous (Model Plant 5) 6.6 6-15
Cost Effectiveness of Low- or no-HAP Coatings 6.7 6-15
Annual Cost for Low- or no-HAP Coatings 6.8 6-15
Small Business Impact (Low- or no-HAP Coatings) 6.9 6-16
"Beyond the Floor" Cost Estimates 6.10 6-18
Equipment Costs 6.10.1 6-18
Operating Costs 6.10.2 6-19
Recordkeeping and Reporting Costs 6.10.3 6-19
Computer Costs 6.10.4 6-20
Performance Testing Costs 6.10.5 6-20
"Beyond the Floor" Costs Estimates 6.11 6-21
Windows and Doors Subcategory 6.11.1 6-21
Flooring Subcategory 6.11.2 6-21
Interior Paneling and Tileboard Subcategory 6.11.3 6-21
Other Interior Panels Subcategory 6.11.4 6-21
Exterior Siding, Doorskins, and Miscellaneous Subcategory 6.11.5 6-21
Cost Effectiveness for "Beyond the Floor" Option 6.12 6-22
Annual Costs for "Beyond the Floor" Option 6.13 6-22
Small Business Impact ("Beyond the Floor" Option) 6.14 6-22
Comparison of Cost Options 6.15 6-28
Reference 6.16 6-28
VI
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List of Figures
Figure 2-1. Simplified Curtain and Roll Coater Diagrams 2-7
Figure 2-2. Simplified Flow, Vacuum, and Pneumatic Coater Diagrams 2-8
Figure 2-3. Generic Coating Line Schematic for Prefmished Interior Lauan
Plywood Paneling 2-11
Figure 2-4. Generic Coating Line Schematic for Prefinished Molded Doors
and Door Skins 2-14
Figure 2-5. Generic Coating Line Schematic for Prefinished Woodgrain Moulding 2-17
Figure 3-1. Thermal Incinerator-General Case 3-15
Figure 3-2. Regenerable-Type Thermal Incinerator 3-18
Figure 3-3. Schematic of a Typical Catalytic Incineration System 3-19
Figure 3-4. Typical Carbon Adsorber Operating Continuously with Two Fixed Beds 3-25
List of Tables
Table 1 -1. Recommended RACT Limits from the CTG for the Factory Surface
Coating of Flatwood Paneling 1-4
Table 1-2. Summary of California AQMD VOC Limits 1-4
Table 1-3. State Regulations for the Surface Coating of Wood Building Products 1-7
Table 2-1. SIC Codes Representing the Wood Building Products Industry 2-3
Table 2-2. SIC Codes Representing the Wood Building Products Surface Coating
Industry Survey 2-3
Table 2-3. Primary Organic HAP Emitted by the Wood Building Products Industry 2-23
Table 2-4. Organic HAP Emissions by SIC Code 2-24
Table 2-5. Primary Organic HAP Emitted by Surface Coating of Wood Building
Products 2-24
Table 3-1. Emission Reduction Techniques Used by Coating Process/End Use 3-4
Table 3-2. Add-On Control Efficiencies Currently Achieved by End-Use Product 3-13
Table 4-i. Summary of Wood Building Product (Surface Coating) Model Plants 4-3
Table 4-2. Doors and Windows Subcategory 4-5
Table 4-3. Flooring Subcategory 4-6
Table 4-4. Interior Wall Paneling and Tileboard Subcategory 4-6
Table 4-5. Other Interior Panels Subcategory 4-7
Table 4-6. Exterior Siding, Doorskins, and Miscellaneous 4-8
Table 4-7. Model Plant Coating and Solvent Use Profile 4-10
Table 4-8. Overall Facility Organic HAP Emission Limits by Subcategory 4-12
Table 5-1. Summary of Primary Air Impacts-Existing Sources 5-3
Table 5-2. Summary of Doors and Windows Air Impacts 5-3
Table 5-3. Summary of Flooring Air Impacts 5-4
Table 5-4. Summary of Interior Wall Paneling and Tileboard Air Impacts 5-4
Table 5-5. Summary of Other Interior Panels Air Impacts 5-5
vn
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List of Tables (continued)
Pat
Table 5-6. Summary of Exterior Paneling, Doorskins, and Miscellaneous Air Impacts 5-6
Table 6-1. Labor Rates for Recordkeeping and Reporting 6-6
Table 6-2. Recordkeeping and Reporting Labor Requirements 6-9
Table 6-3. Computer Equipment Cost Summary 6-11
Table 6-4. Summary of Recordkeeping and Reporting Costs 6-11
Table 6-5. Doors and Windows (Model Plant 1) MACT Costs 6-13
Table 6-6. Flooring (Model Plant 2) MACT Costs 6-13
Table 6-7. Interior Wall Paneling and Tileboard (Model Plant 3)
MACT Costs 6-13
Table 6-8. Other Interior Paneling (Model Plant 4) MACT Costs 6-14
Table 6-9. Exterior Siding, Doorskins, and Miscellaneous (Model Plant 5) MACT Costs .6-14
Table 6-10. Cost Effectiveness of MACT 6-17
Table 6-11. "Beyond the Floor" Cost Options for Doors and Windows 6-23
Table 6-12. "Beyond the Floor" Cost Options for Flooring 6-24
Table 6-13. "Beyond the Floor" Cost Options for Interior Wall Paneling and Tileboard 6-24
Table 6-14. "Beyond the Floor" Cost Options for Other Interior Paneling 6-25
Table 6-15. "Beyond the Floor" Cost Options for Exterior Siding, Doorskins,
and Miscellaneous , 6-26
Table 6-16. "Beyond the Floor" Cost Effectiveness 6-27
Vlll
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Chapter 1
Introduction
1.0 OVERVIEW
Section 112 of the Clean Air Act (CAA) requires the U. S. Environmental Protection Agency
(EPA) to establish emission standards for all categories of sources of hazardous air pollutants
(HAP). The national emission standards for hazardous air pollutants (NESHAP) must represent
the maximum achievable control technology (MACT) for all major sources. The CAA defines a
major source 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, 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 initial source category list was published on July 16, 1992 (57FR31576) and "Rat Wood
Paneling (Surface Coating)" was included as a source category.1 After initial meetings with
industry trade groups and stakeholders, the EPA learned that interior paneling products are no
longer manufactured in large quantities in the United States (U. S.). The EPA also discovered
that there are other wood panel and related building materials with surface coating operations
resulting in significant organic HAP emissions that are not addressed in current or future
regulations. In promoting the CAA objectives to enhance the Nation's air quality and the
productive capacity of its population, the EPA decided to revise the scope to cover the surface
coating of all wood building products, and proposed the name of the source category to be
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changed to "Wood Building Products (Surface Coating)." The change from "Flat Wood Paneling
(Surface Coating)" to "Wood Building Products (Surface Coating)" was published on November
18, 1999 (see 64 FR 63025).
The purpose of this document is to summarize the background information gathered during the
development of the wood building products (surface coating) NESHAP.. The following sections
provide additional details on the background of the wood building products (surface coating)
source category, a summary of existing Federal/State/local regulations, and a brief summary of the
project history.
1.1 BACKGROUND
The wood building products surface coating industry may be divided according to the end use of
the wood building product produced and the performance requirements of the surface coatings
used. Initially, the wood building products surface coating industry was divided into four industry
segments based on primary products: premanufactured homes; panel and reconstituted wood
products; wood windows and doors; and flooring, architectural/specialty millwork, and
miscellaneous. A fifth segment, designated as "small business" facilities, was added in an attempt
to receive representative input from small businesses across the regulated industry.2
The segments identified were found to vary further based on end use of the final product,
performance requirements of the coatings used, and surface coating processes. Some facilities
manufacture numerous products, while some manufacture only panels that are then sold to other
companies for final processing. The performance requirements (i.e., the number of coatings a
product receives) are determined by its end use. Substrates that are finished again after field
installation (e.g., exterior siding) are typically only primed and sold to distributors after which
building contractors or homeowners apply architectural coatings which are formulated for
consumer use. High end products (e.g., interior wall paneling and doors and windows) typically
receive numerous coatings.3 :
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Types of coatings used in the wood building products surface coating industry include, but are not
limited to, fillers, sealers, groove coats, primers, stains, basecoats, inks, and topcoats. Typical
coating application methods include spraying, roll coating, rotogravure cylinder, curtain coating,
flow coating, pneumatic (air knife) coating, brush coating, vacuum coating, and dip coating.3
Further explanation of the various wood building products surface coating industry segments and
the coating operations associated with each is provided in Chapter 2.
Organic HAP are present in many of the coatings applied to wood building products during
surface coating operations. There are also organic HAP present in some of the thinning solvent
and cleaning materials associated with surface coating operations. Xylene makes up almost 50
percent of the organic HAP emitted by the wood building products surface coating industry.
Glycol ethers are also a substantial part of the organic HAP emitted by the industry.4 The organic
HAP associated with various wood surface coating technologies and industry segments are
further discussed in Chapter 2.
1.2 SUMMARY OF EXISTING FEDERAL/STATE/LOCAL REGULATIONS
The EPA published a control techniques guidelines document (CTG) for controlling volatile
organic compound (VOC) emissions from factory surface coating of flat wood paneling in 1978
(EPA-450/2-78-032).5 The CTG recommended emission limits for all coating operations based
on reasonably available control technology (RACT). Table 1-1 summarizes these limits, which
are expressed in pounds of VOC emitted per 1,000 square feet (Ib VOC/1,000 ft2) of coated
surface. These limits can be achieved by either using coatings with VOC content equal to or less
than the limits or by reducing the level of VOCs actually emitted to these levels using add-on
controls. Other significant categories of factory finished flat wood products—exterior siding,
tileboard, and particleboard used as a furniture component—were not reviewed and no emission
limitations were suggested.
1-3
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Table 1-1. Recommended RACT Limits from the CTG for the
Factory Surface Coating of Flatwood Paneling
Product
Printed interior wall panels made of hardwood
plywood and thin particleboard
Natural finish hardwood plywood panels
Class II hardboard panels
Emission rate limit,
IbVOC/l.OOOft2
6.0
12.0
10.0
Equivalent coating limit,
Ib VOC/gallon, less water
(Ib VOC/gal-water)
2.5
3.3
2.8
Most State VOC rules are at exactly these levels, at least for nonattainment areas within the State.
However, a few local and regional agencies, such as California's Bay Area and South Coast air
quality management districts (AQMDs), have adopted stricter standards.6'7 The South Coast
limits also affect the surface coating of exterior wood siding. In addition to exterior wood siding,
the Bay Area limits affect baseboards, veneers, doors, doorskins, wood flat product skins,
tileboard, and wall board. Table 1-2 summarizes the Bay Area and South Coast AQMD VOC
limits.
Table 1-2. Summary of California AQMD VQC Limits
Affected operations
Wood Flat Stock Coating
Adhesive
Inks
VOC limit, Ibs per gal of coating, less water
Bay Area AQMD
2.1
2.1
2.1
South Coast AQMD"
2.1
2.1
2.1
a South Coast AQMD also has a list of "exempt" solvents that may be subtracted from the VOC total.
In addition to the air emission limits on coating operations, the South Coast AQMDs also regulate
cleaning operations. For example, wood building product solvent cleaning of application
equipment, parts, products, tools, machinery, equipment, general work areas, and the storage and
disposal of VOC containing materials used in solvent cleaning operations, shall be carried out
pursuant to Rule 1171. Rule 1171 limits the vapor pressure of solvents used and the cleaning
methods that can be used, requires the use of covered nonporous containers, and prohibits the use
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of propellants. The South Coast AQMD also allows facilities to use add-on controls that achieve
at least 90 percent capture and 95 percent destruction as an alternative to work practices. The
Bay Area allows facilities to use add-on controls to control the emission to the atmosphere to an
equivalent level with an abatement device efficiency of at least 90 percent and meets the
requirements of Regulation 2.
Table 1-3 summarizes other state regulations for wood building products surface coating
operations. In addition to VOC regulations, many states have their own air toxics programs that
may apply to wood building products surface coating operations. These regulations typically
regulate a large number of chemical compounds. Many States have their own list of air toxics,
many of which are also designated as HAP under the CAA. These air toxic regulations typically
specify allowable fenceline concentrations for the individual air toxics. If a facility's annual
emissions of a regulated compound exceed a specified level, the state, may require a facility to
perform dispersion modeling to determine whether the allowable concentration is exceeded at any
point beyond the fenceline. The decision to require modeling depends on several factors,
including the toxicity of the pollutant, its status as a HAP or VOC, the attainment status of the
location, and other considerations. If emissions exceed the allowable concentration, the facility
must reduce emissions.
1.3 PROJECT HISTORY
1.3.1 Data Gathering
In 1998, an information collection request (ICR) was developed by the EPA and approved by the
Office of Management and Budget (OMB) to determine the coating usage, controls, and HAP
emissions associated with wood building products surface coating operations.8 In July of 1998,
the ICR was sent to 45 U. S. wood building product companies expected to have numerous
facilities with surface coating operations. Responses were received from 33 of the wood building
product companies, representing 126 facilities.
In addition to information obtained from these questionnaires, site visits were made to wood
building product surface coating operations. Also, EPA has met with numerous trade
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organizations and industry representatives throughout the rule development process. The primary
trade associations involved with the wood building products (surface coating) NESHAP are the
American Plywood Association (APA)-The Engineered Wood Association, Composite Panel
Association (CPA), National Wood Window and Door Association (NWWDA), Hardwood
Plywood and Veneer Association (HPVA), American Forest and Paper Association (AFPA),
National Wood Flooring Association (NWFA), National Oak Flooring Association (NOFA),
Architectural Woodworking Institute (AWI), American Hardboard Association (AHA),
Manufactured Housing Institute (MHI), Wood Moulding and Millwork Producers Association
(WMMPA), Laminating Materials Association (LMA), Adhesives and Sealants Council, National
Paint and Coatings As'sociation (NPCA), and the Chemical Manufacturers Association (CMA)
Solvents Council.
Based on data obtained from the Toxics Chemical Release Inventory (TRI) data base, the Census
i—
of Manufacturers, trade associations, and industry meetings, the number of wood building product
facilities in the U. S. is estimated to be more than 1,500. However, it is unknown how many of
the estimated 1,500 wood building product facilities actually perform surface coating.
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Table 1-3. State Regulations for the Surface Coating of Wood Building Products*
State
Regulation
No.
Applicability
cutoff
VOC content
limitations
for coatings
.*
VOC
emission
limits
California,
Bay Area
Rule 238
Coating use
<20 gal/yr
Flat wood coatings,
adhesives, and inks
<2.1 Ib/gal
None specified
Delaware
RgAP24\sc23(a)
Coating use
<15 Ib/d
None specified
Interior panels
(hardwood,
plywood, thin
particleboard)
6Ib/I,OOOft2
Natural finish
hardwood panels
I21b/l,000ft2
Hardwood panels of
Class II finish
lOlb/ 1,000 ft2
Wisconsin
NR422
Paneling emissions
<100ton/yr
Adhesive emissions
<15 Ib/month
Adhesive use
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Table 1-3. Continued
State
Alternative
compliance
methods
Allowable
application
equipment
Exemptions
California,
Bay Area
Emission control
system with
overall efficiency
of 90% by weight
Electrostatic
High volume, low
pressure (HVLP)
spray
Hand roller
Flow coat
Roll coater
Dip coater
Paint brush
Detailing or touch-
up operation guns
Wood stock
intended to be used
as furniture or
cabinet
components
Delaware
Emission control
system with
overall efficiency of
95% by weight
None specified
None specified
Wisconsin
Emission control
system with
overall efficiency
of 90% by weight
None specified
Exterior siding
Tileboard
Particleboard used
as furniture
North Carolina
None specified
None specified
None specified
New York
Emission control
system with
overall efficiency of
80% by weight
None specified
None specified
Washington
Emission control
system with
overall efficiency of
90% by weight
None specified
Exterior siding
Tileboard or
Particleboard used as
furniture components
00
Other States have regulations similar to the 1978 CTG (Control of Volatile Organic Emissions from Existing Stationary Sources Volume VII: Factory Surface Coating of Flatwood Paneling),
reference the 1978 CTG directly in the State regulation, or have a general surface coating regulation not specific to the surface coating of wood building products.
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1.3.2 Emissions and Control Data
The available organic HAP emissions and control information for wood building products surface
coating operations has been summarized in Chapters 2 and 3. Most of the information collected is
based on calendar year 1997 and is representative of current practices. In some segments of the
industry, coating operations have shifted away from high-HAP coatings to low- or no-HAP
coatings. Control efficiency data are relevant to current conditions for the purpose of MACT
determination.
1.4 REFERENCES
1. U. S. Environmental Protection Agency. Documentation for Developing the Initial
Source Category List: Final Report. Publication No. EPA-450/3-91-030. Research
Triangle Park, NC. July 1992.
2. Almodovar, P., EPA/CCPG to Project File. List of facilities and industry segments for the
information collection request (ICR) for the development of the Wood Building Product
NESHAP. June 11, 1998.
3. U. S. Environmental Protection Agency. Preliminary Industry Characterization: Wood
Building Products Surface Coating. Publication No. EPA-453/R-00-004. Research
Triangle Park, NC. September 1998.
4. Threatt, B., MRI, to Lluberas, L., EPA/CCPG. November 10, 2000. Documentation of
Database Containing Information from Section 114 Responses and Site Visits for the
Wood Building Products (Surface Coating) NESHAP.
5. U. S. Environmental Protection Agency. Control Technique Guidelines. Publication
No. EPA-450/2-78-032. Research Triangle Park, NC. June 1998.
6. Bay Area (California) Air Quality Management District Regulation 8, Organic
Compounds, Rule 23 - Coating of Flat Wood Paneling and Wood Flat Stock.
December 20, 1995.
7. California South Coast Air Quality Management District Rule 1104: Solvent Cleaning
Operations. September 24, 1999.
8. B. Jordan, EPA: ESD. Information Collection Request for the Wood Building Products
Industry. Research Triangle Park, NC. June 11, 1998.
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Chapter 2
Wood Building Products -
Surface Coating Source Category
This chapter characterizes the wood building product surface coating industry, including facilities,
products, manufacturing and surface coating processes, sources of hazardous air pollutant (HAP)
emissions, and emission reduction techniques. The information in this chapter comes from readily
available sources including the literature, industry representatives, and state and local air pollution.
control agencies. Detailed descriptions of the wood building product surface coating industry can
also be found in the Preliminary Industry Characterization (PIC) document.1
2.0 INDUSTRY PROFILE
A wood building product is defined as "any finished or laminated wood product that contains
more than 50 percent (by weight) wood or wood fibers and is used in the construction, either
interior or exterior, of a residential, commercial, or institutional building." The wood product can
be finished with paints, stains, sealers, topcoats, basecoats, primers, enamels, inks, adhesives,
adhesive-bonded laminates, or temporary protective coatings. This description excludes products
with layers bonded to the substrate as part of the substrate manufacturing process, as well as
surface coating operations involving the manufacture of wood furniture or furniture components.
These categories are covered under other regulations.
The specific products covered by this source category include, but are not limited to, flooring,
shingles, awnings, doors, shutters, mouldings, hardwood/softwood plywood panels, arches,
trusses, hardboard, particleboard, reconstituted wood panels, wall tile, and wallboard.
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Numerous Standard Industrial Classification (SIC) codes are used to describe the wood building
products industry. Table 2-1 lists these codes, their descriptions, and the total number of facilities
included in each, based on the 1992 Census of Manufacturers. Each SIC code includes facilities
that manufacture the substrate (e.g., particleboard or plywood) and may or may not have surface
coating operations because the census does not classify facilities that surface coat separately. The
listed SIC codes also include manufacturers of other products that are not considered wood
building products. While surface coating will only be a part of these total emissions, the SIC
codes and census data served as starting points for conducting analyses of potentially affected
sources.
The EPA sent ICRs to wood building product companies, requesting data for the 1997
manufacturing year, in an effort to receive detailed coating and emission data for the industry
characterization. The facilities that responded, representing only a cross section of the wood
building products surface coating industry, are broken down according to SIC codes in Table 2-2.
All summary data in this chapter are based on the facilities being major or synthetic minor sources
of HAP emissions. According to the Clean Air Act, a major source is "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, 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." A
synthetic minor source is defined as "any source that has the potential to emit HAP but is not a
major source according to Title V classification." In order to avoid being classified a major
source, a synthetic minor facility must adopt some type of enforceable limitation on its potential
HAP emissions to stay below the 10 tons per year of any individual HAP and the 25 tons per year
of any combination of HAPs cutoffs.
2-2
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Table 2-1. SIC Codes Representing the Wood Building Products Industry3'1
SIC Code
2426
2429
2431
2435
2436
2439
2451
2452
2493
Description
Hardwood dimension and flooring mills
Special product sawmills, NEC
Millwork
Hardwood veneer and plywood
Softwood veneer and plywood
Structural wood members, NEC
Mobile homes
Prefabricated wood buildings and
components
Reconstituted wood products
Representative products
Hardwood and parquet flooring
Wood shingles
Awnings, doors, garage doors,
mantels, shutters, mouldings
Hardwood plywood panels,
prefinished hardwood plywood
Softwood plywood panels
Arches, trusses
Mobile buildings, classrooms, homes
Prefabricated floors, panels for
prefabricated buildings
Hardboard, particleboard,
reconstituted wood panels, wall die,
wallboard
Total facilities
831
192
3,155
318
201
895
286
655
288
Based on 1992 Census of Manufacturers.
b Some SIC codes include facilities that do not perform surface coating operations and facilities that do not manufacture wood building products or
are not major sources of HAP.
Table 2-2. SIC Codes Representing Respondents to the Wood Building Products
Surface Coating Industry Survey3
SIC Code
2426
2429
2431
2435
2436
2439
2451
2452
2493
2499
Unknown
Description
Hardwood dimension and flooring mills
Special Product Sawmills, NEC
Millwork
Hardwood veneer and plywood
Softwood veneer and plywood
Structural wood members, NEC
Mobile homes
Prefabricated wood buildings and
components
Reconstituted wood products
Wood Products, NEC
Representative products
Hardwood and parquet flooring
Shutters
Awnings, doors, garage doors,
mantels, shutters, mouldings
Hardwood plywood panels,
prefinished hardwood plywood
Softwood plywood panels
Arches, trusses
Mobile buildings, classrooms, homes
Prefabricated floors, panels for
prefabricated buildings
Hardboard, particleboard,
reconstituted wood panels, wall die,
wallboard
Total facilides
5
0
17
7
0
1
14
0
24
3
2
According to industry information, including only major and synthetic minor sources. Some facilities have multiple SIC code classifications. The>
are counted in both categories.
2-3
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2.1 WOOD BUILDING PRODUCT SURFACE COATING PROCESSES
During the surface coating process, products such as paints and basecoats are applied to the wood
building product. Because many coating products contain volatile components, the process is a
significant source of emissions. Coating lines operate between 100 and 400 feet per minute
(ft/min) depending on the coating method. Typical coating application methods include spraying,
roll coating, rotogravure cylinder, curtain coating, flow coating, brush coating, pneumatic (air
knife) coating, vacuum coating, and dip coating. Each of these methods is discussed below.
In spray coating, a hand-held or automatic spray gun is used to apply the coating. The guns are
typically used in a spray booth. Air is constantly pulled into and vented from the booth to keep
levels of volatile compounds low. Spray technologies, such as conventional air, airless, air-
assisted airless, electrostatic, and high-volume low-pressure (HVLP) spraying, are often used to
coat non-flat pieces. These spray technologies differ in the way the coating is forced out of the
spray gun.
Conventional air spray uses compressed air to atomize the finishing materials. Airless spraying
atomizes the finish by forcing it through a small opening at high pressure. Air-assisted airless
spray uses an airless spray unit with a compressed air jet. This combination finalizes breakup of
the finish and helps to shape the spray pattern on the product. Electrostatic finishing is performed
by spraying negatively charged finish particles onto grounded wood products. High-volume low-
pressure spraying uses a high volume of air delivered at an effectively low pressure to atomize a
finish into a pattern of low-speed particles, typically resulting in less overspray.
Roll coating is a process in which cylindrical rollers apply a limited amount of coating to the
substrate. There are four types of roll coalers: direct roll coalers (rolls in same direction as
product), reverse roll coalers (rolls in opposite direction of product), differential roll coalers (has
Iwo cylinders that move at different speeds), and sock coalers (has a fabric sock over Ihe roll lo
produce a textured finish). Generally, a roll coaler conlains a rubber-covered coating roll and a
smoolh, chrome-plated doclor roll creating a reservoir thai holds Ihe coating material. The
material is held in Ihis reservoir by adjuslable end seals al Ihe ends of Ihe rolls. The doclor roll
2-4
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meters the coating material onto the surface of the coating roll. A feed roll or conveyor belt holds
the stock in contact with the coating roll and helps drive it through the machine. A simplified
schematic of both a direct roll coaler and a reverse roll coater is presented in Figure 2-1.
A rotogravure cylinder is similar to the direct roll coater, only the cylinder is etched and coated
with ink to apply a pattern such as a simulated wood grain onto the substrate. Roll coating is
suitable for the application of coatings when a low-build finish is sufficient.
A curtain coating applicator uses a metered slit (shown in Figure 2-1) or weir to create a free-
falling film of coating that the substrate passes through. Coating pump speed, weir or metered-slit
coating reservoir head, and conveyer belt speed all control the amount of coating applied. Excess
coating is collected in a reservoir and returned to the coating head. Curtain coating is typically
used when a relatively thick coat is required. The rate of panel movement and the controlled
uniform flow of the film of coating determines the coating thickness.
Flow coaters use nozzles and low pressure to create a wet film of coating that the substrate passes
through. Excess coating is collected in a reservoir and returned to the nozzle heads. A simplified
schematic of a flow coater is presented in Figure 2-2. Brush coaters flood a panel with coating
similarly to flow coaters and then use brushes to remove the excess. The excess is collected in a
reservoir and recycled back to the coater.
Pneumatic (air knife) coaters flood a panel with coating similarly to flow coaters and then remove
the excess by exposing the panel to pressurized air. The excess is collected in a reservoir and
recycled back to the coater. A simplified schematic of a pneumatic coater is presented in
Figure 2-2.
A vacuum coater pulls paint up from a reservoir, creating a wall of paint. The substrate passes
through paint and receives a coating. Excess paint is vacuumed off the substrate. Paint thickness
is controlled by vacuum and the conveyor speed. Vacuum coaters can be used in coating
2-5
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applications that require all sides of a substrate to be coated at one time. A simplified schematic
of a vacuum coater is presented in Figure 2-2.
The simplest coating process is dip coating, a process in which the piece is dipped into a vat of
coating, and the excess is allowed to run off. Dip coalers can be used on multi-dimensional pieces
and/or non-typical part configurations.
The industry currently uses primarily waterborne and ultraviolet-cured (UV-cured) coatings,
although some products (i.e., tileboard, fire-resistant paneling) still require solventborne coatings
to provide adequate water, weather, and fire resistance. Quick drying time is another reason why
manufacturers use solventborne coatings, especially when fast line speeds are used. The applied
coating needs to be dry, hard, and cool prior to packaging, otherwise the products have the
potential to stick together when stacked, causing defects or reject material. This problem is
sometimes referred to as "blocking."
Specific coating requirements depend on the product that is being coated, since certain product
uses dictate durability and strength of the coating. The following sections describe these
requirements.
2-6
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Curtain
Coater
Metered Slit
Panel movement
on a conveyer
Recycle Back
to
Pressure Head
Direct
Roll
Coater
Panel movement
on a conveyer
Coating
Applicator
Drive Roll
Reverse
Roll
Coater
Coating
Applicator
Doctor Blade
Reverse Roll
Panel movement
on a conveyer
Drive Roll -*4 J
. Figure 2-1. Simplified Curtain and Roll Coater Diagrams.
2-7
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Flow
Coater
Panel
Movement
Coating
Recycle Back
to
Nozzle
Vacuum
Coater
Panel
Movement
Recycle to
Paint Trough
Vacuum
Coating
Pneumatic or
Brush
Coater
Non-atomizing Fan
Spray Nozzle
Panel Movement
on Conveyer
9oaBn» Air Knife
or
Rotating Brush
Recycle Back
to
Nozzle
Figure 2-2. Simplified Flow, Vacuum, and Pneumatic Coater Diagrams.
2-8
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2.1.1 Interior Paneling
The original control technique guideline (CTG), developed by the EPA in 1978, only covered
surface coating of interior paneling. Since the CTG was published, the use of interior paneling
has decreased dramatically. One wood industry coating supplier estimates that the production of
traditional interior paneling has decreased 75 percent over the last two decades due to the
increased popularity of wallpaper and use of dry wall. Most interior paneling manufactured today
is manufactured outside of the United States (U. S.). However, there is still production in the
U. S. that will be covered by this regulation. There are three primary types of interior paneling:
paper laminated, printed, and natural finish. The finishing processes for each type are discussed
below.
2.1.1.1 Paper Laminated Paneling
These panels are laminated with a decorative paper. Polyvinyl acetate (PVA) is the primary
adhesive used for laminating, but urea-formaldehyde resins and contact adhesives are also used
forUimited applications. Grooves are often cut in the panel after lamination and then usually
sprayed with water-based pigmented coating. The overspray is then ordinarily cleaned up with
low solids water-based clear coating which is applied by rollcoaters. A protective waterborne
topcoat is typically applied with a roll coater over some paper laminated panels.
2.1.1.2 Printed Interior Paneling
A typical coating process for printed interior panels includes filler, basecoat, ink, and topcoat.
Groove coats are also used for finishing the grooves cut in the paneling. The filler is typically a
waterborne or UV coating that is applied using reverse roll coating. After the filler is applied,
typically a waterborne basecoat is applied, typically with a direct roll coater. The inks are applied
with a rubber offset gravure printer. Several ink colors may be applied to reproduce the
appearance of wood or other substrates such as marble or textured cloth. One or two coats of a
clear protective topcoat are then applied with a direct roll coater. Both waterborne and UV-cured
topcoats are used.
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2.1.1.3 Natural Finish Interior Paneling
Stains, toners, sealers, and topcoats may all be used to produce the final finish. A pigmented
groove coat is also applied to the panel grooves. Stains, applied with a direct roll coater, give the
wood a uniform color. A toner may then be applied with a direct roll coater to seal the stain.
Filler is then applied using a reverse roll coater, in preparation for the sealer, used to protect the
wood from moisture and provide a smooth base for the topcoat. Finally, one or more layers of
topcoat are applied with a direct roll coater or a curtain coater. The topcoat may be waterbome
or UV-cured, although the other finishes are typically waterborne.
Figure 2-3 shows a generic coating process diagram for prefinished interior lauan paneling. First,
a sander smooths and cleans the substrate to ensure a suitable surface for coating adhesion. A
reverse roll coater applies filler to the paneling and grooves are cut into the panels. Spray guns
apply a groove coat to protect the surface of the grooves. Then the panels are sanded again
before a direct roll coater applies one or two layers of basecoat. Before being printed with an
artificial wood grain by a rotogravure cylinder, the basecoat must be cured in an oven. The panels
then receive a topcoat from a direct roll coater. Finally, the panels are oven-dried, cooled, and
packaged for storage and shipment.
Due to the reasons outlined in Chapter 1, the flatwood paneling source category is being
proposed to be expanded to include categories of wood building products that were not covered
by the original CTG. The following paragraphs describe these products and their associated
coating processes.
2-10
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Purchased
or
Manufactured
Panels
Sand
Filler
(reverse roll
coaler)
Cut Groove
Coat Groove
(spray gun)
Sand
Basecoat
(direct roll coater)
Packing,
Shipment
Oven
Top Coat
(direct
roll coater)
Wood Grain
Print
(rotogravure)
Oven
Basecoat
(direct roll coater)
Figure 2-3. Generic Coating Line Schematic for Prefinished Interior Lauan Plywood Paneling.
-------
2.1.2 Exterior Siding
Exterior siding may be made of a solid wood such as cedar, of hardboard or waferboard, or of a
relatively new product known as cementitious board. Siding made of solid wood is typically
finished in the field, although some finishing is done in the factory on a limited basis. Hardboard
siding is typically primed in the factory, usually with waterborne coatings; a final coating is
applied in the field using consumer architectural paint. Waferboard siding utilizes a coated paper
overlay with a waterborne primer.
Cementitious board, which consists of approximately 10 to 30 percent wood fiber and 70 to
90 percent cement, has been used extensively in Europe and is growing in popularity in the U. S.
Several companies are in the process of opening, or have recently opened, new facilities to
produce cementitious board for use in the U. S. Some industry representatives and end users
state that cementitious board has several advantages over hardboard in that it is more resistant to
moisture, termites, and fire than hardboard. As with hardboard siding, cementitious board is
typically primed in the factory with the final coating applied in the field. However, some board is
sold unfinished or prefmished. Both the primers and topcoats are typically either waterborne or
UV cured.
2.1.3 Doors and Doorskins
Door and doorskin manufacturing are substantially differentiated processes in practice. Doorskins
are thin pieces of wood, such as veneer or fiberboard, used on the outside surfaces or facings of a
door. Doors are made by applying adhesive to a core and frame, and then pressing a doorskin on
either side of the core and frame. Door assembly or door manufacturing operations are not
usually done at the doorskin manufacturing location. However, the door factory may finish the
doorskins and/or the doors and frames. These finishes are generally water-based, but smaller
operations may use solvent-based finishes.
Doorskins are produced on high-speed finishing lines using low-volatile organic compound
(VOC) and HAP coatings. The predominant market for door skins are the door manufacturers
2-12
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themselves, who use them in their own manufacturing processes. The following paragraphs are
generic descriptions and typical coating applications for different door products.
2.1.3.1 Solid Wood Doors
Solid wood doors are typically constructed from multi-layers of veneer or flat pieces of wood
over a wooden core. These doors are usually finished by a spray application of stain, sealer, and
topcoat using solvent, waterborne, or UV coatings.
2.1.3.2 Hollow Core Doors
Hollow core doors are constructed of flat pieces of veneer or plywood built into a hollow wood
frame. They can be plywood veneer doors, flat composite doors, or molded doors. The typical
surface coating processes for plywood veneer doors include solventborne, waterborne or UV-cure
stains, sealers, and topcoats applied via spray or direct roll coat methods. Flat composite doors • •
are coated with solventborne or waterborne sealers, fillers, basecoats, inks, and topcoats. The ink
is printed while other applications are typically applied via spray or direct roll coat. Molded doors
are usually primed and prefinished using waterborne or UV-curable coatings. Figure 2-4 displays
generic coating process diagrams for molded and smooth-face doors. A sander smooths and
cleans the substrate to ensure a suitable surface for coating adhesion. A reverse roll coater applies
filler to the doors. The doors are sanded again before a direct roll coater applies a stain. After
ovens dry the stain, the doors receive a topcoat from a direct roll coater. Finally, the topcoat is
cured, and the doors are cooled and packaged for storage and shipment.
2-13
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Molded Door Spravbooth Line
Purchased
or
Manufactured
Doors
Door Cleaner
Stain
(spray guns)
Air Dry
Spray Booth
Enclosure
Top Coat
(spray guns)
Air Dry
Padking,
Storage,
and
Shipment
I
£
Flat Composite or Plywood
Veneer Door Skin Line
Purchased
or
Manufactured
Doors
Sand
Stain
(direct roll
coater)
Oven
9
Top Coat
(direct roll
coater)
UV Cured
Pac
cina.
Storage,
and
Shipment
Figure 2-4. Generic Coating Line Schematic for Prefmished Molded Doors and Doorskins.
-------
2.1.4 Tileboard
Tileboard is a type of Class I hardboard that resembles tile and is used as a splashboard around
sinks, tubs, and showers. While most hardboard is finished with waterborne primers and
topcoats, tileboard is finished with solventborne coatings because waterborne coatings do not
provide the required moisture resistance. Emissions from the solventborne coatings are controlled
with thermal oxidizers at some facilities. Otherwise, the solvent emissions are uncontrolled and
vented directly to the atmosphere.
2.1.5 Flooring
Hardwood flooring is cut and grooved, and then is typically finished in 8- by 12-foot strips. The
industry uses both waterborne and solventborne stains and primarily UV-cured topcoats which are
typically applied with a roll coaler. Laminate flooring is becoming increasingly popular in the
U. S. and is produced by using adhesives (typically urea formaldehyde or melamine formaldehyde)
to apply a paper backing to one side of a thin piece of particleboard and a decorative laminate to
\
thd other side. The adhesive is usually applied with a roll coater while the decorative laminate and
backing paper may be applied to the particleboard using pressure and high temperatures.
2.1.6 Window Frames and Joinery
Window frames and joinery are typically finished with either flow coaters or spray guns. Both
waterborne and solventborne coatings are used. Solventborne coatings are required for some
products, particularly those with a long warranty, because they are more durable and provide
better protection than the waterborne coatings. Some products are also dipped in a water
repellant/preservative treatment (usually consisting of wax, mineral spirits, etc.) before finishing.
2-15
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2.1.7 Shutters
Shutters are usually roll-, spray-, or dip-coated with a protective and/or decorative coating.
Waterborne coatings are typically used for finishing. While this product will be covered by the
wood building product (surface coating) NESHAP, none of the surveyed facilities reported any
coating activities involving these types of products, so industry information is not available to
clarify its coating processes. It is expected that the coating systems are comparable to those used
on other exterior products such as siding, doors, and windows.
2.1.8 Moulding and Trim
While exterior use of these products is growing, these decorative or ornamental wood products
are usually used around interior doors and windows. The products are typically spray-coated or
flow-coated with waterborne or solventborne coatings. Additionally, factories which are finishing
wood moulding and trim products may also be finishing a considerable amount of plastic
mouldings and trim. The surface finishes for. plastic usually require coatings which are more
technically difficult to use and apply than coatings used for wood substrates.
Figure 2-5 represents a generic coating process for high-end woodgrain millwork. The substrate
is cut to the size and milled to the shape of the final product. A sander smooths and cleans the
substrate to ensure a suitable surface for coating adhesion. A flow coater applies a basecoat,
which is then dried in an oven. If needed, a second basecoat is applied. A wood grain ink is
applied by a rotogravure cylinder. Then the millwork receives a topcoat from a curtain coater.
Finally, the millwork is oven-dried, cooled, and packaged for storage.
Other products and finishing lines can incorporate any number of combinations of coalers,
sanders, ovens, etc. The combination typically depends upon the use of the final product.
2-16
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Purchased
or
Manufactured
Panels
Sand
Filler
(reverse roll
coaler)
Cut Groove
Coat Groove
(spray gun)
Sand
»,
Basecoat
(direct roll coater)
to
Packing,
Storage, and <-
Shipment
Oven
Top Coat
(direct roll coater)
Wood Grain
Print
(rotogravure)
Oven
Basecoat
(direct roll coater)
Figure 2-5. Generic Coating Line Schematic for Prefmished Woodgrain Molding.
-------
2.2 COATINGS
Types of coatings used in the wood building products industry include, but are not limited to,
fillers, sealers, groove coats, primers, stains, basecoats, inks, and topcoats. Fillers are used to fill
pores, voids, and cracks in the wood and to provide a smooth surface. Sealers seal off substances
in the wood that may affect subsequent finishes and also protect the wood from moisture.
Groove coats cover grooves cut into panels and assure the grooves are compatible with the final
surface color. Primers are used to protect the wood from moisture and provide a good surface
for further coating applications. Stains are non-protective coatings that color the wood surface
without obscuring the grain. Basecoats provide color and hide substrate characteristics. Inks are
used to print decorative designs on printed panels or produce a simulated wood grain. Pigmented
and clear topcoats provide protection, durability, and gloss.
2.2.1 Coating Technologies
The most prevalent form of emission control for the wood building products (surface coating)
source category is the use of low- or no-HAP coatings.
2.2.1.1 Solventborne Coatings
Solventbome coatings are typically used in applications where water, fire, abrasion or weather
resistance is an issue. In addition, solventborne coatings typically have quick drying times. This
allows facilities to operate coating lines much faster and dedicate less floor space to curing/drying,
and prevents incomplete drying of products that could subsequently stick together in shipment.
However, because most manufacturers are subject to VOC and air toxics regulations limiting air
emissions, low-VOC and low- or no-HAP coatings are being developed as replacements for
conventional solventborne coatings in many applications.
2.2.7.2 High-Solids Coatings
High-solids coatings are solventborne coatings that have reduced organic solvent content and are
typically applied by either spray or roller methods. High-solids coatings can be used to reduce
HAP/VOC emissions. Based on equivalent solids applied, the higher solids coating results in
2-18
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lower emissions than a traditional finish. One disadvantage of changing from solventborne
coatings to high-solids coatings is the issue of viscosity. Since high-solids coatings have higher
viscosities than conventional coatings, different application equipment may be required, such as
heating units, to reduce viscosity.
2.2.1.3 Waterborne Coatings
Waterborne coatings are coatings in which water is the main solvent or dispersing agent in a
polymer or resin base. Organic solvents are also added to the coating to aid in wetting, viscosity
control, and pigment dispersion. Each type of waterborne coating exhibits different film
properties depending on the type of polymers in the formulation. The organic polymers found in
waterborne coatings include alkyds, polyesters, vinyl acetates, acrylics, and epoxies, which can be
dissolved, dispersed, or emulsified. While these coatings are not typically free of VOC, their use
can reduce VOC emissions by as much as 70 percent. However, disadvantages can include grain .
raising, increased drying time, and low gloss. Some facilities may be able to use waterborne
coatings for some finishing steps, but because of certain customer or performance requirements,
not all coating steps can be easily switched,
Another disadvantage for waterborne coatings is the cost of new equipment since the use of such
coatings requires the facility to convert to stainless steel lines and equipment. Waterborne
coatings can use the same types of application equipment as conventional solventborne coatings;
however, equipment used to apply waterborne coatings must be dedicated to waterborne
coatings. This is because solventborne coating residues are incompatible with waterborne
coatings and must be completely removed from the equipment before water-based coatings can be
used, which is a laborious and uneconomical process. Moreover, additional costs may be incurred
because some equipment that is susceptible to corrosion, including tanks, piping, and process
equipment, may require replacement.
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2.2.1.4 Ultraviolet Radiation-Cured (UV-Cured) Coatings
Radiation curing is a technology that utilizes electromagnetic radiation energy to affect chemical
and physical change of organic finish materials by the formation of cross-linked polymer
networks. One type of radiation used is UV light. The primary components of UV-cured
coatings are multi-functional polymers, mono-functional diluent monomers, and the photo-
initiators. A photo-initiator absorbs the UV light and initiates the curing process. The diluent
serves as a viscosity modifier for the finish and is similar to a traditional solvent in this regard, but
most of the diluents in UV finishes polymerize and becomes part of the coating film. Only the
diluent in the coating that does not reach the.piece is emitted. The curing process is very fast (as
little as one or two seconds), and provides a final film that is stain-, scratch-, and mar-resistant.
The UV-curable finishes are often considered to contain up to 100 percent solids because 100
percent of the components react to form the coating. Due to the generally high solids content of
these types of coatings, high film thicknesses can be achieved with fewer coats or process steps
than with lower solids conventional coatings. Because curing requires "line of sight" radiation,
these types of coatings are ideal as flat panel or component part finishes.
Ultraviolet radiation-cured coatings have three components: oligomers, monomers, and
photochemical initiators. The oligomers provide most of the desired coating properties, such as
flexibility, hardness, and chemical resistance. The monomers decrease the viscosity of the
polymers and improve other features such as gloss, hardness, and curing speed. The
photochemical initiators are unstable chemicals that form protons or free radicals when
bombarded by UV radiation to initiate the cross-linking process. Ultraviolet-cured coatings are
cured by medium-pressure mercury vapor lamps.
Two categories of UV coatings are currently in use: (1) acrylate epoxies, urethanes, and
polyesters known as "free radical" types, and (2) cationic epoxies. As the names imply, free
radical UV coatings contain photochemical initiators that release free radicals when bombarded by
UV light, whereas the photochemical initiators in cationic epoxies produce protons. Free radical
UV coating technology is older and is the most commonly used type of UV coating. However,
2-20
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cationic epoxies are being developed with superior properties and are expected to eventually
replace free radical-type UV coatings.
The UV coatings have the advantages of rapid curing, low process temperatures, low-VOC and
HAP content, and lower energy costs due to the elimination of drying ovens. Additionally, UV
application and curing equipment occupy less plant space than conventional coating and drying
equipment. However, UV coatings are more expensive than conventional coatings. Also, UV
coatings require specialized equipment; consequently, retrofitting an existing coating line involves
a significant capital investment.
2.2.1.5 Electron-Beam (EB) Curable Coatings
Electron-beam curable coatings generally consist of non-solvent-containing liquids applied to a
substrate and converted into a solid film within a fraction of a second upon exposure to a beam of
electrons. Curing may be defined as the conversion of liquid to solid. Electron-beam coatings are
usilally applied to flat surfaces such as flooring, door skins, and some interior panels.
*
Typical application techniques for EB-cured coatings are spray, roll coat, and curtain coat.
Electron-beam-cured coatings can be clear or pigmented. Although the initial capital investment
for equipment may be substantial, users may increase productivity and efficiency. Coating cost
comparisons with other technologies should be made on a solid pound basis (i.e., the cost of a
solventborne or waterborne coating should be divided by the non-volatile percentage)2.
2.3 CHARACTERIZATION OF HAP EMISSIONS
2.3.1 HAP Emissions
Based on the 1994 and 1995 emissions data from EPA's Toxic Release Inventory (TRI) System
database, methanol, formaldehyde, xylene, toluene, and methyl ethyl ketone (MEK) are the
primary HAP emitted by this source category. Some inorganic HAP are also emitted from this
industry, but the total inorganic HAP emissions are less than 1 percent of the total HAP emissions
and are, therefore, not being regulated by the NESHAP. Table 2-3 presents the primary organic
2-21
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HAP emitted by facilities included in the SIC codes of interest as reported in the 1994 TRI
database. Table 2-4 lists total HAP emissions by SIC code.
Several of the organic HAP listed in Table 2-3 are not emitted from the finishing of wood building
products or associated emission sources (e.g., cleaning and gluing). Many, such as acetaldehyde,
hydrochloric acid, and chlorine, are likely emitted from the substrate manufacturing process or
other processes at the facility.
Some of the organic HAP listed, such as methanol, formaldehyde, and phenol, are emitted from
both the finishing process and the substrate manufacturing process, so the total emissions reported
are likely higher than actual emissions from the surface coating process. Unfortunately, the TRI
data base does not provide sufficient information to apportion the emissions to a particular
process.
Using the estimates received from ICR responses for the 1997 reporting year, overall organic
HAP emissions were broken down according to specific organic HAP. These totals are listed in
Table 2-5 and are based only on those facilities in the project database designated as major or
synthetic minor sources, according to their Title V status.
A comparison between Table 2-3 and Table 2-5 shows the influence of substrate manufacturing
on the TRI data. According to industry information as reported in ICR responses, the most
common organic HAP from surface coating operations is xylene. However, according to TRI
data, the most common organic HAP emitted from all wood building industries is methanol.
While Table 2-5 shows some methanol being emitted from surface coating operations, the
majority of the methanol emissions are from substrate manufacture.
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Table 2-3. Primary Organic HAP Emitted by the
Wood Building Products Industry3
Pollutant
Methanol
Formaldehyde
Toluene
Xylene (Mixed Isomers)
Acetaldehyde
Methyl Ethyl Ketone
Hydrochloric Acid
Phenol
Chloroform
Methyl Isobutyl Ketone
Certain Glycol Ethers
Dichloromethane
Ethylbenzene
n-Hexane
Styrene
Ethylene Glycol
Cresol (Mixed Isomers)
Chlorine
Methyl Methacrylate
Chloromethane
1,1,1 -Trichloroethane
Dibutyl Phthalate
1 ,2,4-Trichlorobenzene
Diisocyanates
Total
Tons emitted
7,069
1,881
1,261
906
853
635
424
301
227
163
122
106
98
56
52
39
38
22
13
13
10
9
8
5
14,311
% of total
49.40
13.14
8.81
6.33
5.96
4.44
2.96
2.10
1.59
1.14
0.85
0.74
0.68
0.39
0.36
0.27
0.27
0.15
0.09
0.09
0.07
0.06
0.06
0.03
100
a Based on 1994 Toxic Release Inventory (TR1) Systems data.
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Table 2-4. Organic HAP Emissions by SIC Code3
SIC code and title
2426 - Hardwood Dimension and Flooring Mills
2429 - Special Product Sawmills, NEC
2431 -Millwork
2435 - Hardwood Veneer and Plywood
2436 - Softwood Veneer and Plywood
2439 - Structural Wood Members, NEC
2451 - Mobile Homes
2452 - Prefabricated Wood Buildings and Components
2493 - Reconstituted Wood Products
Total
Total annual HAP emissions (tons/yr)
TRI1994
388
1,520
2,267
467
3,120
170
128
50
5,905
16,009
TRI1995
223
3,150
1,664
955
3,679
148
130
32
8,704
20,680
a Based on EPA's Toxic Release Inventory (TRI) System database.
Table 2-5. Primary Organic HAP Emitted by Surface Coating
of Wood Building Products2
Pollutant
Xylenes (isomers and mixture)
Toluene
Ethyl Benzene
EGBE
Methyl Ethyl Ketone
Methyl Isobutyl Ketone
Methanol
Styrene
2-Propoxyethanol
Formaldehyde
Methoxyethoxyethanol
Glycol Ethers
All Other HAPs
Total
Tons emitted
774
144
131
130
58
58
49
38
28
26
19
10
21
1,486
% of Total
52.09
9.69
8.82
8.75
3.90
3.90
3.30
2.56
1.88
1.75
1.28
0.67
1.41
100
a Based on 1997 Industry data.
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2.3.2 Organic HAP Emission Sources and Emission Reduction Techniques
The primary sources of organic HAP emissions associated with wood building products surface
coating operations are the application of coatings, the use of solvents in cleaning and thinning
operations, and the subsequent curing/drying of the coatings. These sources were discussed
previously in this chapter and contribute 1,500 tons of organic HAP emissions from the surveyed
facilities in the project database. There are also four secondary emission sources that emit less
than 50 total tons of organic HAP emissions. These other sources of emissions are listed and
discussed in the following sections.
2.3.2.1 Surface Preparation
These are the areas related to the preparation of the surface of a part or product prior to the
application of a surface coating. This is defined as the removal of contaminants from the surface
of a substrate, or the activation or reactivation of the surface in preparation for the application of
a coating. These operations include sanding/buffing operations and trimming/cutting operations.
Only a small percentage of facilities have any type of system to collect or remove the associated
dust from the air. This is not relevant to the determination of a maximum achievable control
technology (MACT) floor since there are no organic HAP used or emitted, but the associated
dust and wood splintering could be a concern for Occupational Safety and Health Administration
(OSHA) regulations.
Another operation that takes place in some surface preparation areas is pre-heating the wood
pieces in ovens before coating. This practice could allow for use of thicker or higher-solids
coatings since coatings flow more easily onto heated wood surfaces. Again, no organic HAP
materials are used or emitted, but this knowledge could prove useful to reduce the excess use of
thinning solvents.
2.3.2.2 Storage Areas
Storage areas for coatings and/or coating components such as inks, adhesives, caulks, and
solvents are a potential source of organic HAP emissions. According to the ICR information for
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73 facilities with storage areas, the total organic HAP emitted was less than 6 tons. To minimize
emissions from open containers and to reduce the added cost of replacing evaporated materials,
good housekeeping measures can be used. Control devices are not typically required by States
for VOC emissions, but some surveyed facilities currently capture emissions from the storage
area, either from the area/room of emission or directly from the storage tank.
2.3.2.3 Waste and Wastewater Operations
At wood building products facilities that perform surface coating, waste products include waste
coatings, waste solvents, wastewater, sludge, and miscellaneous items such as cleaning rags and
dust from dust collectors. According to ICR information from 61 facilities with waste and
wastewater related HAPs, the HAP emissions totaled 16 tons per year. A majority of the
respondents use closed pipes, tanks, or drums for the transport of waste and wastewater. One-
quarter of the respondents treat the waste on-site, but it is unknown how the remaining wastes are
treated or disposed. Since the final disposal is not known, air emissions should be minimized as
much as possible by good housekeeping practices, such as covered waste containers.
2.3.2.4 Mixing Operations
Mixing of paints used in surface coating operations is another potential source of organic HAP
emissions. Mixing operations include all forms of coatings: mixing (combining two or more "as-
supplied" coatings to produce an "as-applied" coating), or formulation (creating a coating using
the most basic components, usually used in specialty applications). According to the ICR
information received from 32 facilities with mixing-related operations, mixing is a relatively small
operation, contributing only 32 tons of organic HAP emissions. Good housekeeping measures
and work practices, such as covered mixers and covered mix/blend tanks, and immediate use of
the mixed coating could reduce excess organic HAP emissions.
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2.4 SUBCATEGORIZATION
As mentioned above, the majority of organic HAP emissions from surface coating operations at
wood building product facilities originate from the application of coatings, the use of solvents in
cleaning and thinning operations, and the subsequent curing/drying of the coatings.
Consequently, the magnitude of emissions depends heavily on the amount and HAP content of the
coatings and solvents used, the application method used, the drying/curing operations used, and
the efficiency of any add-on control devices installed after application and drying/curing
equipment. These factors are determined by the purpose or function of the coating, the surface
coating method, and specific requirements related to the end use of the wood building product.
This section presents the subcategorization scheme for the wood building products surface
coating NESHAP. The subcategories were chosen by taking into account end-use product
performance characteristics, coating usage and performance requirements, organic HAP emission
characteristics, application equipment, and control device applicability. Furthermore, the decision
to subcategorize incorporates knowledge gained during site visits to observe wood building
t
product surface coating operations and/or provided during industry stakeholder meetings. In
addition, the subcategories presented herein reflect most common practices within the industry of
co-locating wood building product surface coating operations within a contiguous facility. Based
on this information, the following subcategories for the wood building product surface coating
industry were determined:
• Doors and Windows;
• Flooring;
• Interior Wall Paneling and Tileboard;
• Other Interior Panels; and
• Exterior Siding, Doorskins, and Miscellaneous.
The rationales for selecting the five subcategories are given below and will be discussed further in
Chapter 5 (Model Plants and Control Options), where the model plants are described for each
i
subcategory. Also, the subcategories will be used to determine the impacts discussed in Chapter 6
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(Summary of Environmental and Energy Impacts) and the associated costs presented in Chapter 7
(Model Plant Control Costs).
2.4.1 Subcategory Descriptions
2.4.1.1 Doors and Windows
The doors and windows subcategory typically includes the priming and sometimes prefinishing of
doors and/or windows including associated door and window components, such as mouldings or
trim. Moulding and trim are decorative or ornamental wood products that are assembled with
doors and windows to create a fixture. Facilities typically produce both doors and windows, and
door and window'components at the same site. This is primarily to achieve consistency in the
appearance of the coatings applied and to aid in the assembly of the end product or complete
fixture (e.g., door or window assembly).
Door and window manufacturing and assembly operations are not typically performed at the same
site as doorskin manufacturing due to the different manufacturing operations and types of
coatings used. Doors are manufactured by applying adhesive to a core and frame, and then
pressing a doorskin on either side of the core and frame. Doorskins are thin pieces of wood, such
as veneer or fiberboard, which are typically only primed at the doorskin manufacturing location
prior to being sent to a location that manufactures a door.
2.4.1.2 Flooring
The flooring subcategory includes facilities involved in the finishing or lamination of a wood
-building product to be used as hardwood or wood laminate flooring. Hardwood flooring is cut
and grooved, and typically finished in 8-foot or 12-foot strips. Laminate flooring is becoming
increasingly popular in the United States and is manufactured using adhesives (typically urea
formaldehyde or melamine formaldehyde) that are applied to a paper backing to one side of a thin
piece of particleboard and a decorative laminate.
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2.4.1.3 Interior Wall Paneling and Tileboard
The interior wall paneling and tileboard subcategory includes the application of a coating to a
panel used only as a wall covering. Interior wall paneling is usually grooved, frequently
embossed, and sometimes grain printed to resemble various wood species. The substrate can be
hardboard, plywood, medium density fiberboard (MDF), or particleboard. Tileboard is a premium
interior wall paneling product used in areas of the home such as kitchens and bathrooms. If
tileboard is manufactured at a facility, then interior wall paneling is typically manufactured at the
same facility. Tileboard, however, is not always manufactured at facilities that manufacture
interior wall paneling.
2.4.1.4 Other Interior Panels
The other interior panels subcategory typically includes the application of a coating to interior
panels that are sold for uses other than wall paneling, such as sheathing, insulation board,
pegboard, and ceiling tiles. Panels in this category are normally not embossed, grooved, or grain
painted. Other interior panels are frequently cut to size after coating either by the coater or the
purchaser. In addition to hardwood plywood and hardboard, softboard, fiberboard, particleboard,
and MDF are other substrates that are shipped to, or produced at, wood building products
facilities and used to produce coated interior panels.
Some facilities produce interior panels that are used in final products such as shelving,
drawersides, cabinetry, store fixtures, display cases, and many other wood furniture components.
These types of facilities that are major sources of HAP emissions will not be covered under the
wood building products (surface coating) NESHAP because they are already covered under the
wood furniture NESHAP (subpart JJ).
2.4.1.5 Exterior Siding, Doorskins, and Miscellaneous
Exterior siding may be made of solid wood, hardboard, or waferboard. Siding made of solid
wood and hardboard is typically primed at the manufacturing facility and finished in the field,
although some finishing may be performed during manufacturing on a limited basis. Exterior trim
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(material made out of siding panels and used for edges and corners around the siding) is typically
manufactured at the same facility and coated with the same coatings as siding.
Facilities that produce waferboard or oriented strandboard (OSB) siding typically use a coated
paper overlay with a water-borne primer. Since the coated paper overlay is often added prior to
the press which is considered to be part of the substrate manufacturing process, these facilities
will not be covered under the wood building products (surface coating) NESHAP, but will be
covered under the plywood and composite wood products NESHAP (subpart DDDD).
Doorskins are thin pieces of wood, such as veneer or fiberboard, used on the outside surfaces or
facings of a door. Doorskin manufacturing is almost always performed at a separate location than
door manufacturing. Also, many facilities manufacture and finish both exterior siding and
doorskins at the same site.
There are several miscellaneous wood building products that are surface coated and for which
there is little or no emissions or product performance information available. However, several of
the miscellaneous wood building products are used on the exterior of buildings or structures
which would require similar protection as exterior siding. These miscellaneous wood building
products include, but are not limited to, shutters, shingles, awnings, laminated veneer lumber
(LVL), and mill work that is not associated with doors and windows or flooring.
2.4.2 Performance Requirements
2.4.2.1 Doors and Windows
The majority of door and window facilities have two separate coating requirements. Doors
(particularly exterior doors) and windows are affected by both inside and outside exposure that
require two different coating systems with unique performance requirements. The exterior
primers and prefinishes must include properties similar to those for exterior siding, including being
able to withstand long-term exposure to sunlight, moisture, and temperature variation. The
interior coatings may or may not be pigmented but must still resist fading due to sunlight. Many
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of these products are treated with a solvent-borne wood treatment/preservative prior to finishing
to resist decay and mildew. Because moulding and trim components will eventually be assembled
with doors and windows, the moulding and trim coatings have the same performance
requirements as the coatings applied to doors and windows.
2.4.2.2 Flooring
Wood flooring requires exceptional performance qualities including long term scratch, abrasion
and stain resistance. Furthermore, it must have finishes that are cosmetically appealing.
Therefore, the coating system used must be adaptable to many different stains and textures.
Solvent-based stains are prevalent in this segment of the industry in order to obtain the clarity of
the wood grain demanded by the customer. Low HAP water-borne stains are available but have
been found by some manufacturers to cause 'fuzziness' in the appearance of the substrate.
2.4.2.3 Interior Wall Paneling and Tileboard
Coated board used for interior wall paneling is subject to industry performance specifications
(consensus standards) for adhesion, hardness, stain resistance, and scrub resistance. Tileboard
must meet even higher performance standards for moisture resistance, adhesion, hardness, stain
resistance, and long-term useful life. Performance requirements for interior wall paneling and
tileboard vary from manufacturer to manufacturer but may range from 15 to 30 years. This
performance requirement far exceeds that available from formulated water-borne coatings of
approximately 5 to 8 years on new wood products. Such performance requirements are met by
using high-temperature aminoplast crosslinkable coatings. These coatings have been tied to
, solvent-borne technology where the main resins are supplied in toluene, xylene and butyl alcohols.
Panel thickness, minimal void, and smoother surfaces are not as critical as in the other interior
panels subcategory. Thickness is not critical as most panels in this subcategory are not multi-
components or assembled into an end-use product requiring strict dimensions. Also, interior wall
paneling and tileboard substrate imperfections are covered by inks, fillers, and topcoats, as
opposed to other interior and exterior panel substrates.
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2.4.2.4 Other Interior Panels
Other interior panels have less stringent requirements (in terms of decorative appearance, scratch
and moisture resistance) on the coating performance than any other wood building products
surface coating subcategory. Typical coating formulation does not include primers, undercoats,
and intermediate coats usually required to protect the substrate from moisture and water damage
or hide substrate imperfections. Furthermore, the use of inks and fillers are normally not required
since other interior panels are not typically used for decorative purposes. Consequently, more
stringent or lower HAP emission rate limits are achievable for these operations. Consistent
thickness, moisture content, minimal voids, and smoother surfaces are critical to this segment of
the industry, in contrast to the interior wall paneling and tileboard subcategory. These panel
substrate properties are more important because reduced coating layers maintain consistent
thickness throughout which is critical during the assembly of the end-product; water-borne
coatings can be applied in relatively high moisture content substrates; and the minimal use of
fillers and inks on the end product requires smooth surfaces as they will not be disguised or filled.
2.4.2.5 Exterior Siding, Doorskins, and Miscellaneous
Exterior siding and trim must be able to withstand long-term exposure to sunlight, moisture, and
temperature variation. Also, consumers expect a warranty to be provided for this type of product.
Doorskins, like siding, can be used as exterior products and also on doors in areas with higher
moisture exposure potential such as bathrooms and closets. Therefore, doorskins have similar
performance requirements to exterior siding and trim. Many of the miscellaneous wood products
included in this subcategory have similar coating performance requirements as exterior siding,
such as the need for protection from adverse weather conditions and the ability to meet warranty
requirements. Coatings in this subcategory used for prefmishing siding contain more organic
HAP than the primers for siding and trim in order to achieve the durability requirements.
Consequently, more resin is applied resulting in the need for more coalescent solvents.
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2.4.3 Coating Usage
The following section discusses the typical coating systems used at the different wood
building products facilities based on a sample of the industry. The following paragraphs explain
the differences and the unique coating usage characteristics of each subcategory.
2,4.3.1 Doors and Windows
Facilities in this subcategory use a combination of basecoats, primers, sealers, stains, and topcoats
depending on the decorative requirements of the final product or whether the product will be used
as an interior or exterior product or both. In addition to the previously mentioned coatings, the
door and window subcategory is the only subcategory where the products are treated with a
solvent-borne wood treatment/preservative prior to finishing to resist decay and mildew. More
than half of the coatings used in this subcategory are wood treatment/preservatives.
Although some doors are manufactured with only a factory-applied primer, most are coated with
V
a ptefmish system that must meet industry performance standards. A typical prefmish system
consists of three steps: stain, sealer, and precatalyzed lacquer. If the door is preprimed, the steps
could consist of two topcoats: tinted topcoat and clear topcoat. The edges are usually coated
with the same coatings as the door faces. The steps may vary depending upon the quality and
aesthetics of the end product desired.
A few door and window manufacturers have been able to switch to water-borne coatings and UV
topcoats and meet the application and end use performance requirements. However, conventional
solvent-based coating technology is still the primary coating technology used in the industry,
particularly for those products with a long warranty, because they tend to be more durable and
provide better protection than the water-borne coating technology.
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2.4.3.2 Flooring
The primary finishing steps for flooring are stain (1 coat), sealer (1-5 coats), and topcoat (1-3
coats). Some woods require fillers to fill the pores in the wood; however, such fillers are
commonly 100 percent solids and therefore not an emission source. Solvent-based stains are
prevalent in the industry in order to obtain the appearance, i.e., clarity of the wood grain,
demanded by customers. No- or low-HAP water-borne stains are also available, but can cause
'fuzziness' in the appearance of the wood grain. The industry uses UV topcoats and sealers
because of the durability properties imparted to the flooring surface and they essentially contain
no HAP.
2.4.3.3 Interior Wall Paneling and Tileboard
Thermoplastic latex topcoats and sealers are used on interior wall paneling in order to provide
physical and decorative performance. Interior wall paneling facilities use a combination of water-
borne, solvent-borne, and in rare instances, UV coatings. Finishing steps typically include up to
five or six layers of coatings, usually including two to three layers of inks on the final product.
Line speeds of 30 to 35 boards per minute require that a coalescent solvent be used which comes
out of the wet film without leaving cure blisters and without leaving residual solvent in the coating
film or substrate. Residual solvent can lead to boards that remain tacky long after they are dry,
creating a problem known as "blocking."
Tileboard coating systems must be moisture resistant and quick drying. The coatings that provide
sufficient water resistance for tileboard have traditionally been tied to solvent-borne technology
with specific resin and solvency requirements. Totally water-bome systems have improved, but
have not consistently achieved the premium performance requirements demanded by consumers
and industry standards. Furthermore, solvent-borne coatings remain the choice when smoothness,
toughness, high shine, or water resistance is desired. These characteristics allow tileboard
surfaces to be less prone to retain dirt on their surface. Tileboard coatings can be formulated with
various resin systems, water-bome and solvent-borne fillers, basecoats and inks,, and solvent-
borne topcoats. UV coatings are not used in tileboard surface coating operations because they
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cannot be applied at the same relative thickness and speed as that of water-borne or solvent-borne
coating systems.
2.4.3.4 Other Interior Panels
Since the end-use products of other interior panels are not typically associated with high
performance coating requirements, the coating systems are simpler with regards to film thickness
and final appearance. Coating technology ranges from low-grade primers to high-grade UV
topcoats depending on the performance dictated by the end use. Flat surfaces and reduced
coating thickness are suitable characteristics for UV technology. Also, panels in this subcategory
are finished with a minimal number of coatings to produce single colors or meet end use
performance requirements.
2.4.3.5 Exterior Siding, Doorskins, and Miscellaneous
The coatings used for finishing exterior siding products are primarily primers; a few facilities
prefinish with basecoats and stains/topcoats. These products are made using substrates that
tolerate high coating line temperatures. In previous years, this industry segment has moved from
solvent-borne to water-borne coating systems without organic HAPs and today the qualified
coatings for exterior siding and trim are mostly water-borne but do contain small amounts of
organic HAP. Doorskins are also usually only primed, with a small amount of prefinishing.
Miscellaneous wood building products included in this subcategory are typically primed to
provide protection from adverse weather conditions and to meet warranty requirements with
prefinishing often completed in the field. Primers make up the majority [82 percent] of the
coatings used at facilities in the exterior siding, doorskin, and miscellaneous subcategory.
2.4.4 Organic HAP Emissions
The following section discusses the typical uncontrolled organic HAPs emitted by the different
wood building products surface coating operations based on a sample of the industry. The
following paragraphs explain the differences and the unique emission characteristics of each
subcategory.
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2.4.4.1 Doors and Windows
The doors and windows subcategory emits the second largest amount of organic HAP emissions
in the industry. The higher organic HAP emissions are related to the continued use of
conventional solvent-based coatings systems for prefinishing doors and windows. The large
amounts of xylene and toluene primarily come from dilution requirements of the commercial resin
systems used in this subcategory and necessary in order to achieve the performance requirements
and coating thicknesses when applied to small and angular shaped surfaces.
2.4.4.2 Flooring
The flooring subcategory has the lowest organic HAP emissions in the industry. The low organic
HAP emissions are primarily due to the widespread use of UV topcoats and sealers that
essentially contain no HAP. The use of UV technology is directly related to the relative flatness
of the surfaces coated for which this technology is best suited for application. Also, many
flooring facilities are beginning to switch from solvent-based stains to low- or no-HAP water-
borne stains.
2.4.4.3 Interior Wall Paneling and Tileboard
The interior wall paneling and tileboard subcategory contains the highest organic HAP emissions
of any of the subcategories. The high organic HAP emissions are directly related to the continued
use of solvent-borne technology to meet the premium performance requirements demanded by
consumers and industry standards. The main resins used in this subcategory are often supplied in
xylene, which is the reason for the large amount of xylene emitted. Ethylene glycol butyl ether
(EGBE) and methanol are also two main organic HAPs that are intentionally added by the coating
suppliers. These organic HAPs are added due to the higher production line speeds that require
that a coalescent solvent be used which comes out of the wet film without leaving cure blisters
and without leaving residual solvent in the coating film substrate. Also, an alcohol is required to
sustain high production speed during the drying of water-borne coatings.
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2.4.4.4 Other Interior Panels
The other interior panels subcategory emits the second smallest amount of organic HAP in the
industry. The small amount of diverse organic HAP emissions is related to the coating technology
used, which ranges from low-grade primers to high-grade UV topcoats. The HAP contents of the
coatings used in the subcategory also vary due to the wide range in product quality, performance,
substrate characteristics, lack of a consensus standard, and end use. However, typically the
emissions are low because of the minimal amounts of coatings required for the typically non-
decorative interior panels.
2.4.4.5 Exterior Siding, Doorskins, and Miscellaneous
The exterior siding, doorskins, and miscellaneous subcategory is in the middle of the industry
regarding organic HAP emissions. The organic HAP emissions are mainly from the coatings used
for prefinishing siding and trim. Even though most of the coatings used in this subcategory have
been switched to water-borne coatings, these coatings still contain some organic HAP due to the
performance requirements of the final product. The coatings in this subcategory must be able to
withstand long-term exposure to sunlight, moisture, and temperature variation along with
standard consumer warranties associated with the product.
2.4.5 Application Equipment
2.4.5.1 Doors and Windows
Doors and windows can be coated on hang lines or flat lines using manual or automated spray
systems. Due to the indentations in most doors, roll coating is often not feasible. The capacity of
a typical door coating line which is used to apply a decorative coating will be much lower, as low
as 100 doors per day, compared to doorskin coating lines where up to 70,000 doorskin units can
be primed in a day. Window frames and joinery are typically finished with either flow coalers or
spray guns. Some doors and windows are dipped in a wood treatment/preservative prior to
finishing. This technique is preferred when products contain curvatures, angles, and edges that
need to be protected.
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2.4.5.2 Flooring
Hardwood flooring facilities apply coatings using roll coalers. The adhesive used at laminate
flooring facilities is also usually applied with a roll coater. Alternatively, the decorative laminate
and backing paper may be applied to the substrate using pressure and high temperatures.
2.4.5.3 Interior Wall Paneling and Tileboard
Most interior wall paneling is coated using roll coalers and in some rare occasions is coated using
spray equipment. Tileboard facilities typically coat using a combination of roll coalers and curtain
coalers. Some lileboard facilities (due lo surface embossing) are restricted lo Ihe use of curtain
coalers for application of fillers, basecoals, and lop coats. As stated previously, UV coatings
cannot be applied to Ihe required Ihickness using Iradilional curtain coaler technology. Roll
coalers are used for lopcoal application on flal surfaced lileboard. Gravure printers are used lo
apply any ink prinl lo interior wall paneling and lileboard final products.
2.4.5.4 Other Interior Panels
Other interior panels are coaled using roll coalers, or sprayed and ihen roll coaled. Thickness
requiremenls mandate Ihe use of Ihese application techniques. Furthermore, Ihese application
equipmenl techniques are besl suilable for UV cure technology.
2.4.5.5 Exterior Siding, Doorskins, and Miscellaneous
Exterior siding, doorskin, and miscellaneous coalings are applied using many differenl coaling
application melhods, including: direcl roll coaling (DRC), reverse roll coaling (RRC), curtain
, coating, automatic air-assisted airless guns or automatic high-velocity low-pressure (HVLP) guns.
Componenls of exterior siding such as exterior Irim may also be coated using Ihe same coating
application methods to malch Ihe performance as well as Ihe decorative requiremenls of the
exterior siding. Shutters and olher miscellaneous exterior producls are typically roll, spray, or dip
coaled wilh a protective and/or decorative coaling. LVL is typically roll coaled or sprayed wilh a
protective sealer.
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2.4.6 Control Device Applicability
2.4.6.1 Doors and Windows
Door and window facilities reported controlling some organic HAP emissions with add-on control
devices, including carbon adsorbers and catalytic oxidizers. The use of add-on control devices is
better suited to this segment of the industry due to high inlet concentrations associated primarily
with the continued use of solvent-borne coatings containing significant amounts of organic HAP.
2.4.6.2 Flooring
Thermal oxidizers were reported to be used to reduce the organic HAP emissions associated with
surface coating of flooring products. The use of thermal oxidizers is more amenable to this
segment of the industry due to high inlet concentrations associated primarily with the use of
solvent-borne stains.
2.4.6.3 Interior Wall Paneling and Tileboard
Thermal oxidizers were reported to be used to reduce the VOC emissions associated with surface
coating of interior wall paneling and tileboard products. (Many of the VOC contained in the
solvents are also organic HAPs.) The use of thermal oxidizers is available to this segment of the
industry due to high inlet concentrations.
2.4.6.4 Other Interior Panels
None of the facilities responding to the ICR reported any add-on control devices related to the
organic HAP emissions associated with surface coating of other interior panel products.
Extremely low organic HAP concentrations in the coatings used and UV cure technology makes
the application of organic HAP control equipment ineffective.
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2.4.6.5 Exterior Siding, Doorskins, and Miscellaneous
None of the facilities responding to the ICR reported any add-on control devices related to the
organic HAP emissions associated with surface coating of exterior siding, doorskins, or
miscellaneous products. Very low inlet concentrations due to the use of low- or no-HAP water-
borne coatings do not support installation of control devices for this segment of the industry.
2.4.7 Conclusions and Subcategorization Rationale
2.4.7.1 Doors and Windows
This segment of the industry is faced with two separate coating problems due to the exposure to
both inside and outside environments, which require radically different performance requirements.
First, the primers and prefmishes that will be subject to exterior conditions must have properties
similar to those of exterior siding. Second, the coatings subject to interior conditions must have
properties similar to interior coatings that may or may not be pigmented, but must still resist
ultraviolet [sunlight] damage.
Related to those stringent performance requirements, doors and windows are the only products in
the industry that require solvent-borne wood treatment/preservatives prior to finishing. More
than half of the coatings [57 percent] reported by the facilities in the database are high-HAP
content wood treatment/preservative coatings. These are low-solids solvent-borne coatings that
must penetrate the wood to protect the wood from moisture and decay. There are no low- or no-
HAP alternatives for these coatings and the average organic HAP content was 19.5 Ib HAP/gal
solids based on a sample of door and window facilities.
The sharp angles, small areas, and openings associated with moulding and trim of doors and
windows are more difficult to coat than the other relatively flat surfaces coated in the other
subcategories of this industry. Door and window surface coating operations utilize either hang or
flat lines and coat using spray systems due to non-flat surfaces that prevent the use of roll coating.
Line speeds for doors and windows are also much slower than most "flat" products (e.g., 100
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doors per day versus 70,000 doorskins per day). Dip tanks are sometimes used for the wood
treatment/preservative coatings, which allows the product to soak in the coating.
Although some doors are marketed with only a factory-applied primer, most are coated with a
prefinish system that must meet industry performance standards. The prefmish system used is
either solvent-based aminoplast technology or conventional solvent-based coating technology.
Conventional solvent-based coating systems are typically used for interior doors while solvent-
based aminoplast technology is used primarily for exterior doors to impart weather resistance
characteristics without compromising aesthetic requirements. The commercial resin systems
available for mixing with aminoplast coats are diluted with xylene and/or toluene. The
performance requirements and various coating operations of this industry segment justify its
subcategory.
2.4.7.2 Flooring
Flooring is limited by the coating types used including the predominant use of solvent-borne stains
and UV sealers and topcoats. Based on a sample of the industry, UV sealers and topcoats
accounted for approximately 65 percent of all coatings and zero (0) HAP emissions. Stains made
up the other 35 percent of coatings and averaged 23.5 Ib HAP/gal solids. No other industry
segment has this unique finishing scenario. Solvent-based stains are prevalent in the industry and
some industry representatives argue they are needed in order to obtain the clarity of the wood
grain. Recent technology advancements over the past few years have moved to water-borne
stains which in the past have tended to cause 'fuzziness' in the appearance of the wood grain. In
addition to the hardwood flooring products, the use of adhesives in laminated flooring
distinguishes this subcategory from the remainder of the industry and consequently provides
sufficient justification for a subcategory.
2.4.7.3 Interior Wall Paneling and Tileboard
Interior wall paneling and tileboard are the primary components of the interior panel product
subgroup of wood building products. Product specifications are established by consensus
standards for both interior wall paneling and tileboard. Interior wall paneling has more decorative
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. coating requirements than other subcategories and is typically manufactured at the same facilities
as tileboard, although in much smaller quantities. Tileboard, a premium interior wall paneling, has
even more stringent product performance requirements (i.e., adhesion and hardness standards,
household stain, scrub and moisture resistant while maintaining a relative smooth surface)
compared to standard interior wall paneling.
Decorative appearance (embossed, grooved or grain printed) and performance of the intermediate
and end products require multiple coating layers and coating steps far exceeding other
subcategories. Production speeds of 30 to 35 boards per minute require that coalescent solvents
be used which come out of the wet film without leaving cure blisters and without leaving residual
solvent in the coating film or substrate. Residual solvents can cause product 'blocking' (products
sticking together) during storage. Tileboard coatings average 5.9 Ib HAP/gal solids and interior
wall paneling coatings average around 1.6 Ib HAP/gal solids. Both products utilize high-
temperature aminoplast crosslinkable coatings which are used on substrates that can tolerate
higher processing temperatures. These coatings have traditionally been tied to solvent-borne
technology where the main resins are supplied in toluene, xylene, and butyl alcohols. The
aforementioned coating elements of this industry segment justify a separate subcategory.
2.4,7.4 Other Interior Panels
Other interior panels make up the rest of the interior panel product subgroup of wood building
products. In this segment of the industry, product specifications are established between the
buyer and seller and not by consensus standards. These products are used for interior applications
other than wall paneling or tileboard and use fewer coating layers. Other interior panels typically
are produced with a single color and have fewer coating steps, less stringent product performance
requirements, and some UV applications which allow lower organic HAP emission rates. Primers
and basecoats comprise 32 percent of all the coatings used on these products and average 1.8 Ib
HAP/gal solids; prefinishes (clearcoats, paints/inks, sealers, stains, and topcoats) make up 47
percent of the coating usage and average 1.7 Ib HAP/gal solids. These product differences justify
a subcategory.
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2.4.7.5 Exterior Siding, Doorskins, and Miscellaneous
This industry segment involves exterior products that must have coatings able to withstand
extreme and long-term weather conditions. The predominant use of primers (82 percent of all
coatings) relates to a compatibility issue for all subsequent coating layers and warranty provisions.
These primers are low HAP-content coatings that average 0.1 Ib HAP/gal solids. The prefinishes,
including basecoats, sealers, stains, and topcoats, have a higher average HAP content,
0.6 Ib HAP/gal solids, and comprise the remaining 18 percent of the coatings used by these
facilities. The typical siding facility produces mainly primed siding, but also has a small
percentage of prefinished material as well. Also, many exterior siding facilities also coat
doorskins at the same location. The miscellaneous wood building products in this subcategory are
often used for exterior purposes and have the same coating requirements as exterior siding and
trim.
In summary, an important aspect in the determination of subcategories for wood building
products surface coating operations relates to the differences in the performance requirements
[decorative, smoothness, scratch resistance, moisture resistance, etc.] of the coatings used which
relates to the type [solvent-borne vs. water-borne] and the amount of coatings required to meet
the end-product specifications. The effectiveness of an applied coating system depends on the
following: the extent to which the adhesion of the coating to the substrate or other coating layers
can take place, the chemical nature and physical properties of the coating material, and the
severity of service environment. The durability and quality of coatings depend on cohesion and
adhesion properties. Coatings and surface multiplicity differences as outlined in this memorandum
justify the subcategorization of the regulated industry.
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2.5 REFERENCES
1. Midwest Research Institute. September 1998. Preliminary Industry Characterization:
Wood Building Products Surface Coating.
2. Research Triangle Institute. Radiation-Cured Coatings. [Online], Available:
http://cage.rti.org/altern.cfm/. September 29, 1999.
3. Lluberas, L. R., EPA/CCPG to Project File, Docket A-57-92. November 10,2000.
Documentation of Database Containing Information from Section 114 Responses and Site
Visits for the Wood Building Products (Surface Coating) NESHAP.
4. Hanks, K., Bullock, D., and Nicholson, B., MRI. April 28, 2000. Summary of Responses
to the 1998 EPA Information Collection Request (MACT Survey) - General Survey.
5. Boerst, T., ABTco, to Reeves, D., MRI. September 7, 1999. Wood Building Products
Finishing MACT.
6. Reeves, D., Marshall, A., and Saltis, A., MRI, to Almodovar, P. September 15, 1998.
Site Visit - Perstorp Flooring, Incorporated; Garner, North Carolina Integrated Rule
Development for Surface Coating of Flatwood Paneling: PMACT and Pre-BAC
Determination.
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Chapter 3
Emission Control Techniques
This chapter discusses organic HAP emission control techniques that are currently being used for
surface coating operations at wood building product facilities. Section 112 of the Clean Air Act
(CAA) requires the U. S. Environmental Protection Agency (EPA) to establish emission standards
for all categories of sources of HAP.
There are several approaches to reducing organic HAP emissions (and VOC emissions) resulting
from wood building products surface coating operations. The primary approach, focusing on
pollution prevention, is to substitute currently used materials for low- or no-HAP materials
(coatings, adhesives, inks, thinning solvents, cleaning materials, etc.). Waterborne coatings and
radiation-curable coatings, such as ultraviolet (UV) or electron beam (EB) coatings, do not
contain or emit significant amounts of organic HAP compared to conventional solventbome
coatings. High-solids coatings can also be used to reduce organic HAP emissions. Solventbome
coatings, powder coatings, radiation-curable coatings, and in some cases waterborne coatings can
all be formulated as high-solids coatings. Only waterborne coatings and radiation-curable
coatings will be discussed in this chapter because they are the most common coatings currently
being implemented by the industry.
Another method used to limit organic HAP emissions resulting from wood building products
surface coating operations is the use of capture systems and add-on control devices to destroy or
remove the organic HAP from the air stream. Add-on control devices can be divided into two
categories: combustion devices and recovery devices. The primary combustion control devices
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used in the industry are thermal and catalytic oxidizers. The primary recovery control devices
used in the industry are carbon adsorbers. Capture systems and add-on control devices are also
discussed in this chapter.
Table 3-1 summarizes available information on the emission reduction techniques used by wood
building products surface coating operations. The information was obtained from the wood
building products ICRs sent to facilities in 1998. The two major factors that influence the
emission reduction technique used are: (1) the applicability of Federal, State, or local regulations
affecting wood building product surface coating operations; and (2) the availability of low- or no-
HAP coatings meeting end use performance requirements of the various wood building products.
3.1 POLLUTION PREVENTION TECHNIQUES
The following sections discuss pollution prevention alternatives for reducing organic HAP
emissions associated with wood building products surface coating operations. Some of these
alternatives, such as the use of waterborne coatings, are widely used throughout the wood
building product industry, while others, such as UV-cured coatings and EB-cured coatings, are
used in a smaller number of applications. The low- or no-HAP coatings that are currently in use
throughout the industry, the emerging technologies that are beginning to be introduced
throughout the industry, and the organic HAP reductions that each one of these offers are
identified and discussed in this section. The organic HAP reductions identified in this chapter
have been calculated based on a source switching from higher-HAP coatings to low- or no-HAP
coatings. Finally, the types of surface coating operations for which these coatings are currently or
could potentially be used are also identified and discussed herein.
The types of coating materials currently used by wood building product surface coating
operations in general have been identified previously in Chapter 2. Coating types include paints,
stains, sealers, topcoats, basecoats, primers, enamels, inks, adhesives, adhesive-bonded laminates,
or temporary protective coatings. Low- or no-HAP coatings have been developed for almost all
of these coating types. The most common low-or no-HAP coatings that are being used or
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potentially could be used to replace the traditional solventborne coatings include waterborne and
radiation-curable coatings, such as UV-cured coatings and EB-cured coatings.
3.1.1 Waterborne Coatings
Waterborne coatings are coatings in which water is the main fluidizing media (i.e., the fluid able to
dissolve the resin). Resins that are associated with waterborne coatings have a distinctly different
chemistry than those associated with solventborne coatings. The primary difference in the two
types of resins is the hydrophilic (i.e., water compatibility) properties of the waterborne coating
resins. Almost any resin can be modified for use with waterborne coatings. The most common
waterborne coating resins are acrylics, epoxies, vinyls, alkyds, and polyurethanes.1
There are three distinct types of waterborne coatings according to how the resin is liquidized.
Waterborne coatings may be emulsions, solutions, or dispersions.1 The various resins determine
the cured film properties of the finish. However, there is one common feature: each type of
waterborne coating employs water as the major solvent or carrying liquid for the resins.2'3 The
three waterborne coating types are discussed in more detail below.
An emulsion is a colloidal suspension (i.e., the resin is in the form of discrete water-insoluble
spherical particles of high molecular weight uniformly dispersed in water). Waterborne emulsion
coatings can be called water-emulsion coatings and are also referred to as latex coatings.1
A solution is a homogeneous dispersion of one or more substances (i.e., resins with low molecular
weight) into another substance. The resins associated with waterborne solution coatings contain
chemically reactive groups which form polar groups that allow water-reducibility and, thus, true
solutions of resins in water. Waterborne solution coatings are also called water-soluble coatings.
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Table 3-1. Emission Reduction Techniques Used by Coating Process/End Use"
Coating/industry segment
No. of coatings using emission reduction techniques
UV
EB
Non-HAPh
waterbornc
Non-HAP"
solventborne
HAP-containing
waterborne
coatings +
capture/control
HAP-containing
solventborne
coatings +
capture/control
HAP-containing
waterborne coatings
(no emission
reduction)
HAP-containing
solventborne coatings
(no emission
reduction)
Wood building products surface coating operations
Doors and Windows'1
Flooring11
Interior Wall Paneling and
Tileboard0
Other Interior Panels'
Exterior Siding, Doorskins,
and Miscellaneous8
7
8
1
19
2
0
0
0
1
0
28
0
18
27
31
9
2
0
2
0
1
0
2
0
0
3
1
5
0
0
31
0
6
26
38
80
3
12
6
0
' These data are from a 1997 industry survey and the information collection request (ICR) sent to wood building product manufacturers conducted in 1998 by the EPA.
b The non-HAP waterborne and solventborne coatings may still potentially include some amount of VOCs.
c The emission reduction data for the doors and windows subcategory represents 11 facilities (9 companies).
11 The emission reduction data for the flooring subcategory represents S facilities (1 company).
c The emission reduction data for the interior wall paneling and tileboard subcategory represents 6 facilities (4 companies).
' The emission reduction data for the other interior panels subcategory represents 13 facilities (5 companies).
1 The emission reduction data for the exterior siding, doorskin, and miscellaneous subcategory represents 12 facilities (6 companies).
-------
A dispersion coating is a system of dispersed resin particles of a medium molecular weight (not as
high as the emulsion resins and not as low as the solution resins) suspended in a liquid. The
dispersion resins have slight polarities that allow some degree of solubility. Because of the slight
solubility of the resins in water, the dispersion formulations are not true solutions or emulsions.*
However, waterborne dispersion coatings are similar enough to waterborne emulsion coatings
that they are generally considered the same paint type. Waterborne dispersion coatings can be
referred to as water-dispersible coatings; however, this terminology is imprecise because all
waterborne resins are water-dispersible.1
Waterborne coatings exhibit unique film properties, depending on the type of resin used in the
formulation. The water-emulsion coatings are of a higher molecular weight and, therefore, offer
advantages in the areas of durability and chemical and stain resistance.2'3 Water-soluble
formulations offer high gloss, clarity, and good application properties. However, water-soluble
films are not as durable as the water-emulsions, and the properties of the coatings are very
dependent on molecular weight. Water-dispersible coatings exhibit properties ofthe water-
emulsion and water-soluble coatings. The water-dispersible coatings offer high gloss and good
application properties and are also durable and chemical- and stain-resistant.2
Waterborne coatings can be formulated for air/force drying or for curing, depending on the resins
in the formulation.2'3 Waterborne coatings may cure in the same manner as solventborne coatings.
Curing (the process of changing the freshly applied (liquid) coating to a finished (solid) paint film)
occurs through a variety of cross-linking reactions. Cross-linking reactions occur when partially
polymerized (i.e., partially converted from a simple molecule to a more complex molecule) resins
dissolved in a solvent are heated. As the solvent (in this case water) evaporates, the resin
molecules form new chemical bonds that cannot be dissolved by adding solvent.1
There are several types of coatings that cure by cross-linking; however, the most common types
are oxidizing and heat cross-linking coatings. In oxidizing coatings, a cross-linking reaction with
atmospheric oxygen is triggered when the unsaturated resin is exposed to the air after the solvent
has evaporated. The oxidation process will occur slowly at room temperature or faster at higher
3-5
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temperatures. In heat cross-linking coatings, a certain temperature is required to trigger cross-
linking and curing. At room temperature, the coating will remain sticky on the surface and remain
uncured until heat is added.4
Waterborne coatings may also cure via latex coalescence.2-5 Latex coalescence occurs when a
resin is dissolved in solvent, then dispersed in water. Either the solvent or water then evaporates,
leaving resin particles dispersed in the remaining solvent or water. As the remaining liquid
evaporates, the pressures force the resin particles to coalesce (i.e., form a coating). No
polymerization takes place; these are a special form of nonconvertible coatings.
The organic HAP content of waterborne coatings varies substantially. Waterborne coatings are
usually not completely free of organic HAP. Solvents are typically added to allow adequate
coalescence and film formation, as well as color penetration for pigmented materials.6 Based on
information from the project database, waterborne coatings have an average organic HAP content
of approximately 0.8 pounds per gallon of solids (Ib HAP/gal solids) or 96 grams of organic HAP
per liter of solids (g HAP/L solids). The average solids content of the waterborne coatings in the
data base is 33 percent by volume. Compared to the organic HAP content of solventborne
coatings, the waterbome coatings represent an approximate reduction of 93 percent in organic
HAP content per volume of solids.7 The actual overall organic HAP emission reduction for a
specific wood building product facility depends on the number of finishing steps for which
waterborne coatings can be used in place of higher-HAP coatings.
3.1.2 Radiation-Curable Coatings
Radiation curing is a technology that utilizes electromagnetic radiation energy to affect chemical
and physical change of organic finish materials by the formation of cross-linked polymer
networks.8 There are two radiation curing processes used in the wood building product surface
coating industry: UV-curing and EB-curing. The UV-curing process is currently being used or
implemented throughout all segments of the wood building product industry. The EB-curing
process is much more rare in the industry. The two radiation curing processes are discussed in
more detail in the following sections.
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3.1.2.1 Ultraviolet-Curable Coatings
One type of radiation used for curing is UV light. The primary components of UV-curable
coatings are multifunctional resins (acrylates, acrylated oligomers), diluent monomers, and
photoinitiators. The photoinitiator absorbs the UV light and initiates free radical polymerization,
the curing process.8 The diluent monomer (diluting substance) serves as a viscosity modifier for
the coating, enabling the coating to be applied to the substrate. It is similar to a solvent in this
regard. In traditional UV coatings, however, most of the diluent also polymerizes and becomes
part of the coating film.3 However, the small amount of diluent in the coating that does not reach
the piece and, thus, is not incorporated into the final film, is emitted.
Ultraviolet-curable coatings are convertible coatings; the curing process is via polymerization.
The curing process for UV-curable coatings is very fast. As the substrate is exposed to UV
radiation, the photoinitiator absorbs the light and initiates near-instant polymerization.
Polymerization, or curing, of the material is rapid, providing a final film that is stain-, scratch-, and
maY-resistant.8'9 Coated pieces can immediately be stacked because the curing is so rapid. Other
properties of the UV-cured film include heat resistance, durability, and good build.
Specialized equipment is required to implement a UV-curing system in existing industrial
processes. UV equipment utilizes a non-thermal curing technique, which does not rely on the
production and transfer of heat to initiate chemical reactions. Electricity is the sole source of
energy for both radiation curing processes; however, for the electrical energy to be useful, it must
be converted by the radiation curing equipment to a more convenient form which will affect a
chemical curing reaction. The electricity is converted by means of a gas plasma into UV light
which then initiates the polymerization reaction and curing.8
Ultraviolet-curable coatings do not typically emit substantial organic HAP (due to the
polymerization process discussed above) and often contain up to 100 percent solids when
100 percent of the components react to form the coating. Some UV-curable coatings are
formulated suc,h that some conventional solvent that volatilizes is added along with the diluent
monomer. Based on information from the project database, the organic HAP content of UV-
3-7
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curable coatings is approximately 0.7 Ib HAP/gal solids (84 g HAP/L solids). The average solids
content of the UV-curable coatings in the project data base is 88 percent by volume. Compared
to higher-HAP solventbome coatings, UV-curable coatings represent an approximate reduction of
84 percent in organic HAP content per volume of solids.7 However, as previously stated, a
facility's overall emission reductions depend on the number of coating steps used by a facility that
switches from solventbome to UV-curable coatings.
3.1.2.2 Electron Beam-Curable Coatings
Electron beam-cure (EB-cure) systems are another type of radiation curing system. The primary
components of EB-curable coatings are also multifunctional polymers (acrylates, acrylated
oligomers) and diluent monomers. However, EB-curable systems do not require photoinitiators
because the energy output of the electrons is sufficient to initiate free radical polymerization
within the coating. Methacrylates are generally used where the cure is initiated by EB exposure
because the multifunctional monomer does not UV-cure well.8 Electron beam-cure systems
utilize energy from an electron generator, in the form of a highly directed beam or curtain of
electrons, and is capable of curing a monomer/unsaturated polymer system by free radical-induced
polymerization.
Specialized equipment is required to implement an EB-curing system to existing industrial
processes, however the cost of adding a new radiation-cure line is substantially less than for
adding anew solventbome line.10 The equipment utilizes a non-thermal curing technique, which
does not rely on the production and transfer of heat to initiate chemical reactions. Electricity is
the sole source of energy for both radiation curing processes; however, for the electrical energy to
be useful, it must be converted by the radiation curing equipment to a more convenient form
which will affect a chemical curing reaction. Electrons from an electric heated filament or cathode
are accelerated to high energies where they can be injected directly into the coating to initiate the
polymerization reaction.
Electron beam-curable coatings do not typically contribute substantial organic HAP emissions
(due to the polymerization process discussed above) and can contain up to 100 percent solids
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when 100 percent of the components react to form the coating. Currently, only one facility within
the project database is using an EB-curable coating; consequently, the data is limited. The
organic HAP content of this EB-curable coating is 0.00 Ib HAP/gal solids (0.00 g HAP/L solids).
The solids content of the EB-curable coating in the project data base is 99.9 percent by volume.
Compared to solventborne coatings, using this EB-curable coating represents a 100 percent
reduction in organic HAP content per volume of solids.7 As previously stated, a facility's overall
emission reductions depend on the number of coating steps used by a facility that switches from
solventborne to EB-curable coatings.
3.1.3 Applicability of Low- or No-HAP Coatings
Both solventborne and waterborne coatings are used extensively in wood building products
surface coating operations.7 In recent years, the industry and its coating suppliers have made
significant strides in reformulating most of the solventborne coatings, as described above, to low-
or no-HAP coatings. However, some of these low- or no-HAP coatings may not meet all of the
industries' performance specifications for specific subcategories of the wood building products
surface coating industry. Therefore, this section identifies the subcategories that currently use
low- or no-HAP coatings and discusses the shortcomings of low- or no-HAP coatings that
prevent their current use in all subcategories.
3.1.3.1 Waterborne Coatings
Waterborne coatings are currently being used, at least in part, by all wood building products
surface coating subcategories.7 However, the waterborne coatings currently available are better
suited to certain applications than others. For example:
• Open-pore woods are easier to coat with waterbome coatings than filled-pore woods;
• Darker woods sometimes appear cloudy when coated with waterborne coatings,
though the clarity has improved over the last 10 years;
• Waterborne coatings do not have the rubbability of solventborne coatings, and the
finish is therefore not as glossy where a glossy finish is required; and
"* •* i*
• Waterbome coatings may require a modified drying method (e.g., increased airflow
and temperature).6
3-9
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.Some facilities may be able to use waterbome coatings for some coating steps but not all.
According to coating suppliers, in certain applications only solventbome coatings can be used
because of the problems of grain raising.6 Grain raising is a swelling of the fibers in the wood due
to the absorptance of a liquid, such as water. Grain raising causes the surface of the wood to look
and feel rough.
In addition, some products (e.g., tileboard, fire-resistant paneling) may require solventborne
coatings to provide good water, weather, and fire resistance. Finally, quick drying time is another
reason why manufacturers use solventborne coatings, especially when fast production line speeds
are used. The coating needs to be dry, hard, and cool prior to packaging, otherwise the products
have the potential to stick together when stacked, causing defects or reject material. This
problem is sometimes referred to as "blocking."11
3.1.3.2 Ultraviolet-Curable Coatings
Ultraviolet-curable coatings are currently used in several subcategories in the wood building
products surface coating industry.7 Ultraviolet-curable coatings can be applied using spray
equipment, roll coalers, or curtain coalers. The main problem associated with UV-curing is Ihe
inability lo cure surfaces lhal do nol get direct exposure to the radiation.8 Therefore, UV-curable
coatings are best if used on flat line process operations.12 There are several wood building
products that typically are coated using flat line process operations, including panel and
reconstituted wood products, doorskins, and hardwood flooring. Therefore, the potential exists
for UV-curable coatings to be used in those subcategories of the wood building products industry
where flat line operations exist, and some companies see progress in this direction as discussed in
Section 3.1.2. Currently, the industry is conducting studies in the area of three-dimensional UV-
curing so that UV-curable materials may experience even more widespread use in the future.13
Ultraviolet-curable coatings are feasible and demonstrated for surface coating operations in which
the pieces are flat, with no significant carvings or recessed areas. There are two types of UV-
curable coatings. One type is applied via a curtain coater, roll coater, or similar flat line
apparatus. The UV-curable coatings applied by these methods typically are almost 100 percent
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solids with an organic HAP content close to zero.8 The second type of UV-curable coating is
applied using conventional spray application equipment.
3.1.3.3 Electron Beam-Curable Coatings
Even though electron beam-curable coatings are currently rare in the wood building products
surface coating industry, there are several advantages of EB-curing systems over UV-curing
systems.7 Electron beam-curing systems are capable of curing thicker or more heavily pigmented
coatings than UV-curing systems, because electrons are far more penetrating than UV light.14
Another advantage is that EB-curing systems cure much faster than UV-curing systems. Along
with the advantages mentioned above, the EB-curing system achieves the same quick start and
stop and has minimal space requirements, the low or zero organic HAP emissions, and the rapid
production potential of the UV-curing systems.14
The disadvantages to using EB-curing systems have, however, prevented the implementation of
the curing process throughout the wood building products surface coating industry. Electron
beam-curing systems require an inert gas flush (i.e., nitrogen or argon) to keep air out of the
electron radiation area. This is to prevent electron radiation (EB-curing) in air which can create
ozone and other harsh irritant gases that are severe health hazards for humans. Workers must
also be kept away from the inert gas due to the lack of oxygen. Also, the radiation source of EB-
curing systems is dangerous to workers, and must be shielded and protected using safety
interlocks to ensure workers do not accidentally get close enough to be harmed.14
EB-curing lines, unlike solventborne lines, do not require explosion proof equipment, thermal
drying ovens, LEL monitoring, and air pollution control equipment. Therefore, EB-curing lines
do have some benefits over solventborne lines.10 The data suggest that the disadvantages to using
EB-curing systems have outweighed the advantages for the wood building product industry. UV-
curing systems are more typically being used due to lower installation costs.8 The higher
installation costs associated with EB-curing systems are mainly due to the necessary precautions
required to ensure worker safety.
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3.2 CAPTURE SYSTEMS
Capture systems are designed to collect solvent-laden air and direct it to a control device. In most
wood building products surface coating operations, solvent is removed from the coated wood
building product by evaporation in and around the coating applicator and in the subsequent curing
oven. The exhaust from the coating applicators and ovens and the associated organic HAP
emissions are only partially captured, if at all, and typically not controlled.
Differences in capture efficiency contribute much more to the variation in overall efficiencies than
the choice of control device. Reported capture efficiencies, as listed in Table 3-2, ranged from
estimates of less than 26.5 percent to the 100 percent capture which is assumed for systems
meeting the requirements of permanent total enclosures (PTEs). Test procedures are available to
determine capture efficiency and to confirm the presence of PTEs.15'16
Capture systems can be improved by extending the system to collect additional solvent-laden air
from other operations, such as mixing/thinning operations and cleaning operations, by
constructing additional hooding and enclosures. Capture can be improved to (nearly) 100 percent
for any given production line or group of production lines by retrofitting walls and increasing
ventilation to meet the requirements of a PTE. In PTEs, all air flow is into the enclosure except
for exhaust points, which are. ducted to an afterburner. In order to meet the criteria for a PTE,
the following must apply:17
• The sum of the areas of all openings (doors, windows, etc.) must be less than
5 percent of the sum of the enclosure's surface area (walls, floor, and ceiling).
• Air must flow inward at all openings with an average face velocity of at least 200 feet
per minute (ft/min).
• All sources emitting VOCs inside the enclosure must be "distant" from any openings
(at least 4 equivalent diameters).
• All exhaust streams must be directed to a thermal oxidizer or other final control
device.
• All windows and doors not counted in the 5 percent of area rule must be closed during
normal operations.
3-12
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Table 3-2. Add-On Control Efficiencies Currently Achieved by End-Use Product3
End-use product
Method of
control
0)
Range of CE
achieved, %b
(2)
Range of DE
achieved, %c
Best OCE achieved by
a particular line, %d
(3)
CE
(4)
DE
(5)
OCE
[(4) X (5)]
Wood Building Product Surface Coating Operations
Doors and Windows
Flooring
Interior Wall Paneling
and Tileboard
Carbon
adsorber
Catalytic
oxidizer
Thermal
oxidizer
Thermal
oxidizer
26.5 - 46
83
100
75 - 89.2
90-95
85
95
94.1-99.6
46
83
100
89.2
95
85
95
99.6
43.7
70.6
95
88.8
a These data are from the 1998 ICR of the wood building product industry conducted by the EPA. Only three of the surveyed facilities identified
control devices for the removal of HAP/VOC. Many facilities identified control devices for the removal of paniculate matter (PM); however, these
control devices will not be considered in the development of the M ACT floor.
b "CE" means capture efficiency.
c "DE" means destruction efficiency (or control efficiency in the case of the carbon adsorbers).
d "OCE" means overall control efficiency (CE x DE).
3.3 ADD-ON CONTROL DEVICES
Add-on control devices in the wood building products surface coating industry are addressed
within two categories: combustion control devices and recovery devices. Combustion control
devices are defined as those devices used to destroy the contaminants, converting them primarily
to carbon dioxide (CO2) and water. The combustion control devices evaluated within this section
include thermal incineration with recuperative and regenerative heat recovery and catalytic
incineration.
Recovery devices are used to collect organic HAP prior to their final disposition, which may
include reuse, destruction, or disposal. One recovery device that is addressed in this section is
carbon adsorption in conjunction with regeneration of the carbon bed by steam or hot air.
Another system discussed is a proprietary system that uses oxidant-ozone counterflow wet
scrubbing and granular-activated carbon adsorption with cold oxidation regeneration. Also within
the recovery devices section, information regarding carbon adsorption with final destruction of
organic HAP by incineration is provided.
3-13
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3.3.1 Combustion Control Devices
Combustion is a rapid, high-temperature, gas-phase reaction in which organic HAP are oxidized
to CO2, water, sulfur oxides (SOX), and nitrogen oxides (NOX). If combustion is not complete,
partial oxidation products, which may be as undesirable as the initial organic HAP, could be
released. In order to avoid such occurrences, excess air is added to ensure complete combustion.
More complete process descriptions are provided below for each type of combustion control
device.15
3.3.1.1 Thermal Incineration
Thermal incineration is a process by which waste gas is brought to adequate temperature, and
held at that temperature for a sufficient residence time for the organic compounds in the waste gas
to oxidize.16 Through this technology, the constituents of the waste streams generated by surface
coating operations will be converted to CO2 and water in the presence of heat and sufficient
oxygen.
A schematic diagram of a typical thermal incineration unit is provided in Figure 3-1. Primary
components of the thermal incineration unit include a fan, a heat-recovery device, the combustion
chamber, and the exhaust stack. The heat-recovery device is used to preheat the incoming waste
stream so that less auxiliary fuel is required in the combustion chamber. This type of heat
recovery is known as primary heat recovery and can generally be described as either recuperative
or regenerative. If the exhaust stream is of sufficient temperature and/or heating value so that
little or no auxiliary fuel is needed, heat recovery may not be cost effective and thus may not be
implemented. However, when auxiliary fuel is required, heat recovery can be used to minimize
energy costs.
In order for the thermal incinerator to achieve the desired destruction efficiency, certain key
parameters must be controlled. These parameters include the combustion airflow rate, the waste
stream flow rate, auxiliary fuel requirements, residence time, combustion chamber operating
temperature, and the degree of turbulence between the air and combustible materials. Residence
time is the time required for the initiation and completion of the oxidation reactions. Operating
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Figure 3-1. Thermal Incinerator—General Case.
temperature is a function of the residence time, the oxygen concentration, the type and
concentration of the contaminant involved, the type and amount of auxiliary fuel, and the degree
of mixing.
The destruction efficiency for a particular contaminant is a function of the operating temperature
and residence time at that temperature. A temperature above 1500°F (816°C) will destroy most
organic vapors and aerosols. Turbulence, or the mechanically induced mixing of oxygen and
combustible material, can be increased by the use of refractory baffles and orifices to force
adequate mixing in the combustion chamber. Alternatively, mixing can be enhanced by the use of
over-fire air, the injection of air into the combustion zone at a high velocity, or by a forced air
draft.18
Standard Operating Conditions for Thermal Incinerators. Thermal incinerators
generally operate at a temperature ranging between 1200° and 1600°F (650° and 870°C) and
require a minimum residence time of 0.3 seconds (sec) in the combustion zone.19 Most thermal
3-15
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units are designed to provide the waste gas a residence time of no more than 1 second in the
combustion chambers.20 Thermal incinerators can be designed to control flow rates in excess of
100,000 cubic feet per minute (fWmin) (2,832 cubic meters per minute [mVmin]). Thermal
incineration can control waste streams of organic HAP and VOC concentration from parts per
million (ppm) to 25 percent of the lower explosive limit (LEL). The organic HAP and VOC
concentrations typically cannot exceed 25 percent LEL for safety and insurance reasons.
Heat Recovery in Thermal Incinerators. Heat recovery reduces the incinerator's or other
process' energy consumption. Primary heat recovery means preheating the incoming waste
stream to the incinerator by transferring heat from the incinerator exhaust so the combustion
chamber requires less auxiliary fuel. Secondary heat recovery means exchanging heat in the
exhaust and leaving the primary device for heat recovery to some other medium used in plant
processes.
Recuperative or regenerative devices can be used for primary heat recovery. The waste gas
preheater shown in Figure 3-1 could be a recuperative heat exchanger. As shown in this figure, a
heat exchanger transfers heat to the incoming waste stream from the incinerator exhaust stream.
In a recuperative heat exchanger, the incinerator's effluent continuously heats the incoming
stream in a steady-state process. Choosing a type of heat exchanger depends on the waste gas
flow rate, the desired heat exchange efficiency, the temperature of the incinerator exhaust stream
(used for preheat), and economics. Recuperative heat exchangers can recover 70 percent of the
energy in the incinerator exhaust gas, thereby reducing fuel, the primary operating cost, by
70 percent.21
An incinerator employing regenerative heat recovery is presented in Figure 3-2. Figure 3-2
illustrates a two-chamber design in which process exhaust air is purified in a conventional
combustion chamber but uses two beds of ceramic material to recover thermal energy. The
process exhaust passes through a bed of ceramic heat sink material that was left hot at the end of
a preceding cycle. As the air passes over the ceramic, it extracts heat from the bed. This leaves
the ceramic bed cool at the end of the cycle and raises the air temperature to near the desired
3-16
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thermal destruction temperature (combustion chamber temperature). Firing natural gas, propane,
or fuel oil into the combustion chamber adds heat to reach the destruction temperature. The
airstream leaving the combustion chamber passes through the other ceramic bed, which was left
cool during the preceding cycle. The ceramic bed absorbs the heat from the airstream, leaving the
ceramic bed hot at the end of this cycle and the exit airstream relatively cool.
The inlet and discharge airstreams are reversed, so that the ceramic beds absorb and reject heat
from the airstream on a cyclical basis. When the cycle reverses and the ceramic bed at the inlet
becomes the bed at the outlet, some contaminated air is left in the ceramic bed chamber. The
volume of contaminated air in the inlet heat sink chamber must be displaced into the combustion
chamber before extracting the high-temperature combustion air through it to attain the maximum
overall destruction efficiency from a regenerative thermal incinerator. A system designed to
"purge" the chamber is provided in a three-chamber design. In this system the same type of
absorption/rejection of heat occurs, but the third chamber allows time between inlet and discharge
cycles to purge each chamber at the end of an inlet cycle. Regenerative heat recovery systems can
recover 95 percent of the energy in the incinerator exhaust gas, with a comparable reduction in
fuel, the major operating cost.21
Thermal Incinerator Efficiency. Studies indicate that a well designed and operated
commercial incinerator can achieve at least a 98 percent destruction efficiency (or an outlet
concentration of 20 ppm) of nonhalogenated organics. This destruction efficiency corresponds to
incinerators that are operated at 1600°F (871 °C) with a nominal residence time of 0.75 sec.22
3-17
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MM
I
EMISSION SOURCE
CERAMIC PACKING
HEATING GAS
1
|
I"
COM
C
AUXILIARY
FUEL
CERAMIC PACKING
COOLING GAS
CERAUIC PACKING
COOLING GAS
EMISSION
SOURCE
CERAMIC PACKING
HEATING GAS
AUXUARY
FUEL
COMBUSTION
CHAMBER
Figure 3-2. Regenerable-Type Thermal Incinerator.
3.3.7.2 Catalytic Incineration
Catalytic incineration is comparable to thermal incineration in that organic HAP are heated to a
temperature sufficient for oxidation to occur. The temperature required for oxidation with
catalytic incineration, 300° and 900°F (149° and 482°C), is considerably lower than that required
for thermal incineration, 1200° and 1600°F (650° and 870°C), because a catalyst is used to
promote oxidation of contaminants.23 The catalyst is imposed on a large surface containing many
active sites on which the catalytic reaction occurs. Platinum is the most widely used catalyst;
palladium is also commonly used.24 Because the metals used as catalysts are expensive, only a
thin film is applied to the supporting substrate. Ceramic materials are commonly used as the
supporting substrate.
3-18
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AUXILIARY FUEL Qa(
AUXILIARY FUEL Q
Qaf .
Qa
PREHEAT
CHAMBER
Q
r.
^
CATALYST
CHAMBER
°f
i
Q
w
i
i
•4 DILUTION AIR
O
WASTE GAS
PREHEATER
Q
w
o
0
SECO
ENE
RECC
NDARY
RGY
)VERY
»-
STACK
Figure 3-3. Schematic of a Typical Catalytic Incineration System.
Figure 3-3 is a schematic of a typical catalytic incineration system. As indicated in this figure,
components of the system include a fan, a preheat chamber, a catalyst chamber, a waste gas
preheater (recuperative heat-recovery device), secondary heat recovery, and a stack. The preheat
*
chamber is used to heat the incoming waste stream to the required oxidation temperature, usually
between 300° and 900°F (149° and 482°C) for catalytic incineration.25 The mixing chamber is
used to thoroughly mix the hot combustion products from the preheat chamber with the exhaust
waste stream. This ensures that the stream sent to the catalyst bed is of uniform temperature.
Combustion of the VOC in the waste gas then takes place at the catalyst bed. The catalyst bed
may be a fixed bed or a fluidized bed consisting of individual pellets enclosed in a screened unit.
A heat recovery device is used if supplemental fuel requirements are expected to be high. Many
parameters affect the performance of a catalytic incineration system. The primary factors include
operating temperature, space velocity (inverse of residence time), VOC concentration and species,
and catalyst type and susceptibility to contaminants. The optimum operating temperature depends
on the type of catalyst, as well as the concentration and type of organic HAP. Space velocity is
defined as the volume of gas entering the catalyst bed divided by the volume of the catalyst bed.
In general, as space velocity increases, destruction efficiency decreases.25 One factor that
increases the space velocity is increased temperature. The amount and type of organic HAP
3-19
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determine the heating value of the waste stream and thus the amount of supplemental fuel
required to maintain the desired operating temperature.
The type of catalyst that is used is determined by the particular organic HAP in the waste stream.
Particulates and catalyst poisons in the waste stream can affect the efficiency of the catalyst and
its lifetime. Some materials that are considered catalyst poisons include heavy metals (mercury,
lead, iron, etc.), silicon, sulfur, halogens, organic solids, and inert particulates.25 Particulates and
poisons reduce the activity of the catalyst site, minimizing sites available for the oxidation
reaction. These materials can also mask, plug, or coat the catalyst surface, thereby eliminating
available catalyst sites.
Standard Operating Conditions for Catalytic Incineration. The catalyst bed in catalytic
incinerators generally operates at temperatures ranging between 300° and 900°F (149° and
482°C), with temperatures rarely exceeding 1000°F (538°C). The contact time required between
the contaminant and the catalyst so that complete oxidation occurs is normally 0.3 sec. The
excess air requirements for catalytic incineration units are usually only 1 to 2 percent higher than
the stoichiometric requirements.23-26 Catalytic incinerators can be designed to control waste gas
flow rates up to about 50,000 ft3/min (1,416 nrYmin). The VOC content of the waste stream may
be in the part-per-million range up to 25 percent of the lower explosive limit or LEL.
Catalytic Incinerator Efficiency. A well operated and maintained catalytic incineration unit
can achieve destruction efficiencies of 98 percent, comparable to thermal incineration units. The
destruction efficiency would decrease in the presence of the catalyst poisons and particulates
described above.27
3.3.2 Recovery Devices
Organic HAP in a waste gas stream can be collected through adsorption of the contaminants onto
a porous bed. The contaminants can then be recovered, if desired, by desorption of the bed with
steam or hot air. Contaminants can be condensed and recovered or disposed of after desorption
3-20
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or regeneration. Alternatively, contaminants can be sent to an incinerator for destruction after
regeneration by hot air. The following section discusses the use of activated carbon adsorption
systems followed by steam and hot air regeneration.
3.3.2.1 Carbon Adsorption
The carbon adsorption process used to control organic HAP emissions from waste gas streams
can be subdivided into two sequential processes. The first process involves the adsorption cycle,
in which the waste gas stream is passed over the adsorbent bed for contaminant removal. The
second process involves regeneration of the adsorbent bed, in which contaminants are removed
using a small volume of steam or hot air, so that the carbon can be reused for contaminant
removal.
Adsorption is the capture and retention of a contaminant (adsorbate) from the gas phase by an
adsorbing solid (adsorbent). The four types of adsorbents most typically used are activated
carbon, aluminum oxides, silica gels, and molecular sieves. Activated carbon is the most widely
used adsorbent for air pollution control following wood building products surface coating
operations and is the only type of adsorbent discussed in this section.28 Both the internal and
external surfaces of the carbon are used as adsorption sites. Diffusion mechanisms control the
transfer of the adsorbate from the gas phase to the external surface of the carbon, from the
external surface of the carbon to internal pores, and finally to an active site in the pores.
Adsorption depends on a mass transfer gradient from the gas phase to the surface. Some method
of heat removal from the carbon may be necessary because adsorption is an exothermic process,
depending on the amount of contaminant being removed from the gas phase.29
The two main mechanisms of adsorption are physical adsorption and chemisorption. Physical
adsorption (otherwise known as van der Waals adsorption) uses a weak bonding of the adsorbate
molecules to the adsorbent. The van der Waals forces within the bond are similar to the forces
that attract molecules in a liquid and are easily overcome by the application of heat or the
reduction of pressure. Therefore, regeneration (cleaning) of the adsorbent is possible.
3-21
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Chemisorption uses chemical bonding by inducing a reaction between the adsorbate and the
adsorbent. Recovery of a chemically adsorbed adsorbate is not always possible.30
Regeneration is the process of desorbing (that is, reversing the process and separating the
contaminants from the carbon). Regeneration of the carbon bed is usually initiated prior to
"breakthrough." Breakthrough, as the name implies, is that point in the adsorption cycle at which
the carbon bed approaches saturation and the concentration of organics in the effluent stream
begins to increase dramatically. In other words, the contaminant is no longer adsorbed by the
carbon and, therefore, passes through the process and is emitted into the atmosphere. If the
carbon bed is not regenerated, the concentration of organic HAP in the effluent stream will
continue to increase until it is equal to that of the influent stream or inlet, i.e., the carbon is
saturated.31
Regeneration can be accomplished by reversing the conditions that are favorable to adsorption, by
increasing the temperature and/or reducing the system pressure. The ease of regeneration
depends on the magnitude of the forces holding the VOCs to the surface of the carbon. The most
common method of regeneration is steam stripping. Low-pressure, superheated steam is
introduced into the carbon. The steam releases heat as it cools; this heat is then available for
adsorbate vaporization. Consequently, the organic HAP become separated from the carbon and
airborne. Another regeneration method is the use of hot, inert gas or hot air. With either steam
or hot air regeneration, the desorbing agent flows through the bed in the direction opposite to the
waste stream. This desorption scheme allows the exit end of the carbon to remain contaminant-
free.32
In a regeneration process, some adsorbate, known as the "heel," may remain in the carbon after
regeneration. The actual capacity of the carbon is referred to as the working capacity and is equal
to the total capacity of the carbon less the capacity taken by the heel.31 As heels accumulate or
increase in the carbon, the capture efficiency of carbon adsorption units tends to reduce, resulting
in eventually doing a change-out (replacing the activated carbon with virgin or new carbon).
3-22
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Adsorption units that are commonly used to remove contaminants from waste gas streams include
the following:
• Fixed or rotating regenerable carbon beds;
• Disposable/rechargeable carbon canisters;
• Traveling bed carbon adsorbers;
• Fluid bed carbon adsorbers; and
• Chromatographic baghouses.
Of the five adsorption systems listed above, the first two are most commonly used for air
pollution control. The disposable/rechargeable canisters are used for controlling low flow rates
(less than 100 ftVmin [3 mVmin]) and could potentially be used to control the low-volume flow
rates typical of the wood building products surface coating operations. Only the fixed-bed,
regenerable carbon adsorption system is discussed in this chapter.33
A fixed-bed, regenerable carbon adsorption system is presented in Figure 3-4. The components of
the carbon adsorption system include the following:
• A fan (to convey the waste gas into the carbon beds);
• At least two fixed-bed carbon adsorption vessels;
• A stack for the treated waste gas outlet;
• A steam valve for introducing desorbing steam;
• A condenser for the steam/contaminant desorbed stream; and
• A decanter for separating the HAP condensate and water.
In the system depicted in Figure 3-4, one carbon vessel is being used for adsorption while the
other is being regenerated. Both vessels will alternate in the adsorption and regeneration modes.
The steam is used to regenerate a vessel and is then sent to a condenser. The condensate is a
water and organic HAP mixture. The decanter can be used to separate the condensate into a
water stream and a condensate stream. The resulting water may be treated or discharged to the
3-23
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sewer depending on its measured toxicity. The condensed organics can be recycled (if usable),
used as a fuel, or disposed of.
Hot air or a hot inert gas could be employed in lieu of using steam for regeneration. After
regeneration, the desorbing stream would then consist of an air or gas stream with a high organic
HAP concentration. This air or gas stream could then be sent to an incinerator for final
destruction of organic HAP.
Factors That Affect Adsorption Efficiency. Several factors affect the amount of material
that can be adsorbed onto the carbon bed. These factors include type and concentration of
contaminants in the waste gas, system temperature, system pressure, humidity of waste gas,
residence time, and heel buildup.31
The type and concentration of contaminants in the waste stream determine the adsorption capacity
of the carbon. Adsorption capacity is defined as the pounds of material adsorbed per pound of
carbon. In general, adsorption capacity increases with a compound's molecular weight or boiling
point, provided all other parameters remain constant. There is also a relationship between
concentration and the carbon adsorption capacity. As concentration decreases, carbon capacity
also decreases. However, the^capacity does -not decrease proportionately with the concentration
decrease. Therefore, carbon capacity still exists at very low pollutant concentration levels.31
Increases in operating temperature decrease adsorption efficiency. At higher temperatures, the
vapor pressure of the contaminants increases, reversing the mass transfer gradient. Contaminants
would then be more likely to return to the gas phase than to stay on the carbon. At lower
temperatures, the vapor pressures are lower, so the carbon will likely retain the contaminants.33
3-24
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rroswoo
Figure 3-4. Typical Carbon Adsorber Operating Continuously with Two Fixed Beds.
The system pressure also improves adsorption's effectiveness. Increases in the gas phase pressure
promote more effective and rapid mass transfer of the contaminants from the gas phase to the
carbon. Therefore, the probability that the contaminants will be captured is increased.34
The relative humidity or moisture content of the gas phase reduces the adsorption efficiency.
Although water vapor is not preferentially adsorbed over the contaminants, the presence of water
vapor in the gas phase has been demonstrated to have a negative effect on the adsorption capacity
-*
of the1 carbon. However, the effect of humidity or moisture in the gas phase is insignificant for
3-25
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VOC concentrations greater than 1,000 ppm and during the initial startup of the adsorption cycle
(the carbon is drier). Indeed, some moisture content in the gas phase can be beneficial. For
instance, when high concentrations of contaminants with high heats of adsorption are present, the
temperature of the carbon bed may rise considerably during adsorption due to the exothermic
nature of the process. The presence of water may minimize the temperature rise.31
Adsorption efficiency varies slightly if contaminants don't have enough contact (residence) time
with the active sites of the carbon, which allows mass transfer to occur. Contaminants especially
need this time if many molecules (high-concentration streams) are competing for the same sites.
Residence time of the contaminants with the active sites can be increased by using larger carbon
beds, but then the pressure drop across the system increases, resulting in increased operating
costs.34
Standard Operating Conditions of Carbon Adsorbers, Fixed-bed carbon adsorption
units have been sized to handle flow rates ranging from several hundred to several hundred
thousand ftVmin. There is no obvious practical limit to flowrate because multibed systems
operate with multiple beds in simultaneous adsorption cycles. The organic HAP concentrations of
the waste streams controlled by carbon adsorption units can range from the part-per-billion level
to as high as 20 percent of the LEL. Adsorption systems typically operate at ambient pressure
and temperatures ranging between 77° and 104°F (25° and 40°C).33
Carbon Adsorption Efficiency. Carbon adsorption recovery efficiencies of 95 percent and
greater have been demonstrated to be achievable in well designed and well operated units.35"37
The performance of the carbon adsorption unit is negatively affected by elevated temperature, low
pressure, high humidity, as previously discussed.
3-26
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3.4 REFERENCES
1. Roobol, N.R. Industrial Painting: Principles and Practices. Carol Stream, IL,
Hitchcock Publishing Co. 1991. pp. 79-88.
2. Ballaway, B. New Developments in Waterborne Finishes. Industrial Finishing. December
1989. pp. 24-25.
3. Detrick, G. F. and K. Kronberger. Addressing the VOC Issue in Industrial Finishes.
American Paint and Finishes Journal. September 11, 1989. pp. 42-52.
4. Ref. 1, pp. 226-227.
5. Del Donno, T. A. Waterborne Finishes Outlook Bright. Industrial Finishing. December
1988. pp. 28-33.
6. Contact Report. Caldwell, M. J., and Christie, S., Midwest Research Institute, with
Tucker, R., Guardsman Products, Inc. March 28, 1991. Lower-VOC finishes.
7. Threatt, B., MRI, to Lluberas, L., EPA/CCPG. November 10, 2000. Documentation of
Data Base Containing Information from Section 114 Responses and Site Visits for the Wood
Building Products (Surface Coating) NESHAP.
8. Costanza, J.R., A.P. Silveri, and J.A. Vona. Radiation Cured Coatings. Federation Series on
Coatings Technology. Philadelphia, PA. June 1986. pp. 7-15.
9. Chemcraft Sadolin International, Inc. Wood Finishes. Brochure. Walkertown, NC.
10. Cohen, Gary. Radtech International North America. UV/EB for Beginners From a
Beginner. Coating'99 Conference Proceedings. Dallas, TX. September 21-23, 1999. Pp.
699 - 704.
11. Midwest Research Institute. September 1998. Preliminary Industry Characterization:
Wood Building Products Surface Coating.
12. Loewenstein Dip Continues. Industrial Finishing. May 1993. 69:14-15.
13. Rechel, C. J., RadTech International, to Edwardson, J. A. and J. Berry, EPA/ESB.
October 13, 1993. Potential for reduction of emissions by the use of UV curable finishing
systems.
14. Ref. 1, pp. 229-231.
* •* .:
15. Bethea, R. M. Air Pollution Control Technology. New York, Van Nostrand Reinhold
Company. 1978. p. 395.
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16. Brunner, C. R. Hazardous Air Emissions from Incineration. New York, Chapman and
Hall. 1985. p. 92.
17. Cooper, C. D. and F. C. Alley. Air Pollution Control: A Design Approach. Prospect
' Heights, IL, Waveland Press Inc. 1994. p. 339.
18. Ref. 14, pp. 401-402.
19. Ref. 14, p. 405.
20. Prudent Practices for Disposal of Chemicals from Laboratories. National Academy Press.
Washington, D.C. 1983.
21. Seiwert, J.J. Regenerative Thermal Oxidation for VOC Control. Smith Engineering
Company. Duarte, CA. Presented at Wood Finishing Seminar-Improving Quality and
Meeting Compliance Regulations. Sponsored by Key Wood and Wood Products and
Michigan State University. Grand Rapids. March 5, 1991. 27pp.
22. Farmer, J. R., EPA, to Distribution. Thermal Incinerator Performance for NSPS.
August 22, 1980. 29 pp.
23. Radian Corporation. Catalytic Incineration for Control of VOC Emissions. Park Ridge,
NJ, Noyes Publications. 1985. pp. 4-5.
24. Ref. 14, p. 421.
25. Ref. 21, pp. 12-24.
26. Ref. 14, p. 425.
27. Telecon. Caldwell, M. J., Midwest Research Institute, with Minor, J., M & W
Industries. June 20, 1991. Catalytic incineration.
28. Ref. 14, pp. 375-376.
29. Ref. 14, p. 366.
30. Ref. 16, p. 381.
31. Calgon Corporation. Introduction to Vapor Phase Adsorption Using Granular Activated
Carbon, pp. 11-1 through 11-16.
32. Ref. 14, pp. 382-387.
33. Ref. 19, pp. 4-1 through 4-44.
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34. Ref. 14, pp. 380-382.
35. Crane, G. Carbon Adsorption for VOC Control. U. S. Environmental Protection
Agency. Research Triangle Park, NC. January 1982. p. 23.
36. Kenson, R.E. Operating Results from KPR Systems for VOC Emission Control in Paint
Spray Booths. Met-Pro Corporation. Harleysville, PA. Presented at the CCA Surface
Finish '88 Seminar and Exhibition. Grand Rapids, MI. May 18, 1988. 10 pp.
37. VIC Manufacturing. Carbon Adsorption/Emission Control. Minneapolis, MN.
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Chapter 4
Model Plants and Control Options
4.0 INTRODUCTION
This chapter describes model plants and control options for the five subcategories of the wood
building products surface coating industry as identified in Chapter 2, Wood Building Products -
Surface Coating Source Category. The project database contains information on 47 wood
building products surface coating operations, including 44 "major" sources and three synthetic
"minor" sources (based on Title V classification provided in the ICR responses). It is estimated
that the major source facilities in the project database represent approximately 20 percent of the
wood building products surface coating industry in the United States.1 The model plants
described are based on the collected data from the industry and are used to represent facilities that
are major sources of HAP emissions. A major source is defined as any wood building product
surface coating facility with the potential to emit 10 tons per year (tons/yr) [9.1 megagrams per
year (Mg/yr)], of any individual HAP or 25 tons/yr (22.7 Mg/yr) of all HAP combined. The
model plant information will then be used to estimate nationwide emissions from all major source
wood building product surface coating facilities in Chapter 5 (Summary of Environmental and
Energy Impacts).
Model plants are typically created by averaging multiple parameters from existing facilities in
order to evaluate the general effects of various control options on the source category. The
purpose of model plants in the wood building product surface coating industry is to represent
potentially affected facilities that are not included in the project database. The associated costs
and impacts were developed for each individual facility hi the database and then averaged to
4-1
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determine the various model plants. Then the costs and impacts were scaled to represent the
entire industry of approximately 205 major source facilities. Evaluating control options for the
wood building products surface coating industry using individual facilities makes sense because
the control options vary widely across the industry and across subcategories. Control options
were selected based on the application of presently available low- or no-HAP coatings.
4.1 MODEL PLANTS
The model plants are based on the following: industry and facility data contained in the wood
building products surface coating project database, site visits to wood building product surface
coating operations, and the industry members' feedback provided during several stakeholder
meetings held throughout the development of the NESHAP. The model plants were defined
based on the following parameters: (1) product types, (2) product performance requirements, and
(3) coating limitations. Model plants have been specified for the following five subcategories in
the wood building products surface coating industry:
• Doors and windows;
• Flooring;
• Interior wall paneling and tileboard;
• Other interior panels; and
- Exterior siding, doorskins, and miscellaneous.
Chapter 2 describes the basis for the five wood building products surface coating subcategories in
more detail. Table 4-1 summarizes the five model plants with the number of facilities in each
model plant, the total amounts of coatings and solids used by those facilities, and the associated
organic HAP emissions, both before and after existing add-on controls. Table 4-1 also presents
averages of the data for each model plant.
4-2
-------
Table 4-1. Summary of Wood Building Product Surface Coating Model Plants
Model plant type
Number of facilities (in database)
Total coating usage (gals of coating/yr)
Total coating solids (gals soiids/yr)
Total HAP emissions (Ib/yr) before control
Total HAP Emissions (Ib/yr) after control
Avg HAP emissions (Ib/yr) before control
Avg HAP emissions (Ib/yr) after control
Overall control (%)
Doors and
windows"
11
951,583
196,400
1,239,698
1,147,639
112,700
104,331
7.4
Flooring
5
72,611
49,060
110,602
71,185
22,120
14,237
35.6
Interior wall
paneling and
tileboard
6
1,177,962
483,755
2,124,995
1,260,685
354,166
210,114
40.7
Other
interior
panels
13
1,231,394
451,065
288,617
288,617
22,201
22,201
0.0
Exterior siding,
doorskins, and
miscellaneous
12
5,242,869
2,219,176
3-10,549
310,549
25,879
25,879
0.0
Coatings data from 1 of the 11 window, door, and miscellaneous facilities is considered CBI. Therefore, "Total coating usage," "Average coating
usage," "Total coating solids," and "Average coating solids" are all based on 10 facilities. Emissions information cannot be considered CBI and,
therefore, is based on 11 facilities (9 major source facilities and two synthetic minor source facilities).
4.1.1 Model Plant 1 - Doors and Windows
Model Plant 1 is based on 11 door and window facilities (including 9 major sources and two
synthetic minor sources) in the project database and represents an estimated total industry
population of 50 facilities in the U. S. that are major sources of organic HAP emissions.1 Coating
usage ranges from approximately 100 to 460,000 gal/yr (380 to 1,700,000 Lfyr). Both the
organic HAP emissions before and after add-on controls from the 11 facilities in this subcategory
range from 0 to 300 tons/yr (0 to 272 Mg/yr). The controlled organic HAP emissions from the
11 facilities represent approximately 37 percent of the estimated 1,500 ton/yr of organic HAP
emitted from all of the facilities in the project database.
4.1.2 Model Plant 2 - Flooring
Model Plant 2 is based on five flooring facilities in the project database and represents an
estimated total industry population of 50 facilities in the U. S. that are major sources of organic
HAP emissions.1 However, the MACT floor analysis for this subcategory is based on four
facilities because one facility was found to be unrepresentative of the subcategory. Coating usage
ranges from approximately 1,300 to 37,000 gal/yr (4,900 to 140,000 L/yr). The organic HAP
emissions from, the facilities before and after add-on controls in this subcategory range from 0 to
15 tons/yr (0 to 14 Mg/yr). The controlled organic HAP emissions from the five facilities account
4-3
-------
for approximately 2 percent of the estimated 1,500 ton/yr of organic HAP emitted from all wood
building products surface coating facilities in the project database.
4.1.3 Model Plant 3 - Interior Wall Paneling and Tileboard
Model Plant 3 is based on six interior wall paneling and tileboard facilities in the project database
and represents an estimated total industry population of 15 facilities in the U. S. that are major
sources of organic HAP emissions.1 Coating usage ranges from approximately 30,000 to 320,000
gal/yr (112,000 to 1,200,000 L/yr). The organic HAP emissions from the facilities in this
subcategory before and after add-on controls range from 3 to 286 ton/yr (2.7 to 259 Mg/yr). The
total organic HAP emissions from the six facilities account for 41 percent of the estimated
1,500 ton/yr of organic HAP emitted from all wood building products surface coating facilities in
the project database.
4.1.4 Model Plant 4 - Other Interior Panels
Model Plant 4 is based on 13 other interior panel facilities in the project database and represents
an estimated total industry population of 25 facilities in the U. S. that are major sources of organic
HAP emissions.1 Coating usage ranges from approximately 1,100 to 1,300,000 gal/yr (4,200 to
4,900,000 L/yr). The organic HAP emissions from the 13 facilities in this subcategory range from
0 to 44 ton/yr (0 to 40 Mg/yr). The total organic HAP emissions from the 13 facilities in the
project database account for 9 percent of the estimated 1,500 ton/yr of organic HAP emitted from
all wood building products surface coating facilities in the project database. None of these
facilities use add-on controls.
4.1.5 Model Plant 5 - Exterior Siding, Doorskins, and Miscellaneous
Model Plant 5 is based on 12 exterior siding, doorskin, and miscellaneous facilities (including 11
major sources and one synthetic minor source) in the project database and represents an estimated
total industry population of 65 facilities in the U.S. that are major sources of organic HAP
emissions.1 Coating usage ranges from approximately 58,000 to almost 2,000,000 gallons per
year (gal/yr) [220,000 to.7,600,000 liters/yr (L/yr)]. The organic HAP emissions from the 12
4-4
-------
facilities in the exterior siding, doorskin, and miscellaneous subcategory range from 0 to 54 tons
per year (ton/yr) [0 to 49 megagrams per year [Mg/yr]). The total organic HAP emissions from
the 12 facilities represent 10 percent of the estimated 1,500 ton/yr of HAP emitted from all wood
building products surface coating facilities in the project database. None of these facilities use
add-on controls.
Operating parameters and specifications for all facilities in the project database are broken out by
subcategory in Tables 4-2 through 4-6, including information on coating usage, solids usage,
organic HAP emissions, and overall control efficiencies. The average organic HAP emission
values specified for each model plant in Table 4-1 are overall averages of the total amount of
organic HAP emitted by facilities in each subcategory in the project database, (i.e., totals from
Tables 4-2 through 4-6 divided by the number of database facilities in each subcategory).
Table 4-2. Doors and Windows Subcategory
Blind
facility ID
A-l
A-2
A-3"
A-4
A-5
A-6
A-7
A-8
A-9
A-10
A-ll"
Totals
Coating usage3
(gal of coating)
33,246
36,961
12,820
459,207
CBI
29,151
4,738
259,055
86,600
100
29,706
951,584
Solids usage3
(gal of solids)
5,111
8,247
5,490
79,224
CBI
17,713
2,471
59,906
6,116
42
12,080
196,400
HAP emissions
before add-on
controls (Ibs)
20,116
112,427
53,014
216,374
597,555
34,098
3,311
190,561
6,331
128
5,782
1,239,697
HAP emissions
after add-on
controls (Ibs)
20,116
112,427
53,014
124,316
597,555
34,098
3,311
190,561
6,331
128
5,782
1,147,639
Overall control (%)
0.0
0.0
0.0
42.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
7.4
" Since one of the 11 facilities has associated CBI, the total coating usage and solvent usage are based on the 10 non-CBI facilities.
b Synthetic minor source; therefore, not subject to NESHAP requirements.
4-5
-------
Table 4-3. Flooring Subcategory
Blind facility
ID
B-l
B-2
B-3
B-4
B-5
Totals
Coating usage
(gal of coating)
7,946
37,416
19,273
6,628
1,348
72,61 1
Solids usage
(gal of solids)
5,344
26,219
13,087
3,785
625
49,060
HAP emissions
before add-on
controls (Ibs)
0
30,612
45,519
15,662
19,808
111,602
HAP emissions
after add-on
controls (Ibs)
0
30,612
5,102
15,662
19,808
71,185
Overall control
(%)
0.0
0.0
88.8
0.0
0.0
36.2
Table 4-4. Interior Wall Paneling and Tileboard Subcategory
Blind facility
ID
C-l
C-2
C-3
C-4
C-5
C-6
Totals
Coating usage
(gal of coating)
320,440
154,127
298,173
249,463
125,246
30,513
1,177,962
Solids usage (gal
of solids)
139,841
52,812
129,473
88,837
57,681
15,111
483,755 '
HAP emissions
before add-on
controls (Ibs)
1,077,960
572,756
5,325
49,838
288,012
131,104
2,124,995
HAP emissions
after add-on
controls (Ibs)
213,651
572,756
5,325
49,838
288,012
131,104
1,260,686
Overall control
(%)
80.2
0.0
0.0
0.0
0.0
0.0
40.7
4-6
-------
Table 4-5. Other Interior Panels Subcategory
Blind
facility ID
D-l
D-2
D-3
D-4
D-5
D-6
D-7
D-8
D-9
D-10
D-ll
D-12
x D-13
; Totals
Coating usage
(gal of coating)
13,570
70,832
93,101
7,776
302,758
555,524
12,028
21,243
74,606
1,103
33,413
27,285
18,155
1,231,394
Solids usage
(gal of solids)
5,844
24,233
61,516
2,300
77,269
193,434
5,037
6,622
19,861
870
30,668
12,786
10,626
451,066
HAP emissions
before add-on
controls (Ibs)
4,945
88,277
80,434
0
54
1,086
960
14,267
3,337
1,195
70,804
1,201
22,059
288,619
HAP emissions
after add-on
controls (Ibs)
4,945
88,277
80,434
0
54
1,086
960
14,267
3,337
1,195
70,804
1,201
22,059
288,619
Overall control
(%)
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
4-7
-------
Table 4-6. Exterior Siding, Doorskins, and Miscellaneous Subcategory
Blind
facility ID
E-l
E-2a
E-3
E-4
E-5
E-6
E-7
E-8
E-9
E-10
E-ll
E-12
Totals
Coating usage
(gal of coating)
468,792
146,145
219,551
238,249
237,238
188,132
1,992,450
• 938,766
454,600
93,311
207,094
58,541
5,149,558
Solids usage
(gal of solids)
202,197
61,016
87,602
113,867
97,173
81,144
789,997
390,002
200,634
30,419
135,854
29,271
2,188,757
HAP emissions
before add-on
controls (Ibs)
12,180
14,303
5,725
10,952
6,187
2,526
107,609
40,599
102,724
0
1,951
5,794
310,550
HAP emissions
after add-on
controls (Ibs)
12,180
14,303
5,725
10,952
6,187
2,526
107,609
40,599
102,724
0
1,951
5,794
310,550
Overall control
(%)
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Synthetic minor source; therefore, not subject to NESHAP requirements.
4-8
-------
4.2 MODEL PLANT PARAMETERS
The coating information from the ICR was analyzed to profile the coating usage, by type, for each
of the model plants in the analysis. Table 4-7 presents the coating usage profiles for each model
plant. As can be seen in the coating usage profiles for each model plant, there are distinguishable
differences between the subcategories.
Door and window facilities use a wide variety of waterborne and solventborne coatings.
Solventborne wood treatment/preservatives make up over half of the coatings used by this
subcategory. A few facilities have been able to switch to UV topcoats and sealers.
All of the flooring facilities in the database reported using a combination of UV topcoats and
sealers with a stain. One facility uses a non-HAP solventborne stain, but the rest of the facilities
still use solventborne stains containing HAP.
Interior wall paneling and tileboard facilities use mainly basecoats and topcoats that can be either
waterborne or solventborne. Most facilities are switching to waterborne coatings as recent
technology advancements have improved the coating performance of waterborne coatings.
Coating performance is a high priority for this subcategory for both decorative requirements for
interior wall paneling and moisture resistant requirements of tileboard.3
Other interior panel facilities use a larger variety of mostly waterborne and UV coatings. Several
of these facilities produce laminated particleboard using waterborne adhesives in the process.
Exterior siding, doorskin, and miscellaneous facilities primarily use waterborne primers. Siding is
typically finished in the field, however, a few facilities prefinish siding before it leaves the facility.
4-9
-------
Table 4-7. Model Plant Coating and Solvent Use Profile
Coating type
Adhesive
Basecoat
Clearcoat
Paint/ink
Primer
Sealer
Stain
Topcoat
Wood Treatment/Preservative
Total
Model plants
1
2
3
4
5
Percent of total gallons (%)
0
8
0
0
10
4(UV)
2
18 (UV)
57
100
0
0
0
0
0
39 (UV)
35
26 (UV)
Q
100
12
39
2
3
10
9
2
23 (UV)
0
100
22
9(UV)
3
6
23
20 (UV)
0
17 (UV)
0
100
0
11
0
0
82
3
1
3
0
100
4.3 MAXIMUM ACHIEVABLE CONTROL TECHNOLOGY FLOORS2
The wood building products surface coating industry is basically uncontrolled in terms of organic
HAP Only three facilities in the project database use some form of add-on control device to
reduce emissions of organic HAP. One of the three facilities using add-on controls has switched
some of its solventborne coatings and inks to low- or no-HAP waterborne coatings since the ICR
response was received and no longer uses all of their add-on control devices.3 The trend in the
wood building products surface coating industry is reformulation of coatings to low- or no-HAP
coatings, which is already being done at many facilities and is the best control option to reduce
organic HAP in the industry. Add-on controls (i.e., oxidizers and adsorbers) for coating
application lines and drying/curing equipment, were initially considered for purposes of "beyond
the floor" calculations. However, a preliminary evaluation showed these control options to be
cost prohibitive. Cost details are provided in Chapter 6 for the add-on control alternative
strategies.
Although organic HAP emissions from wood building products surface coating operations are
essentially uncontrolled, there has been pressure in the past for the wood building products
industry to reduce organic HAP emissions. Some facilities have already switched or are in the
4-10
-------
process of switching to low- or no-HAP coatings. The MACT floor limits presented in Table 4-8
are primarily based on those facilities using coatings with relatively low- or no-HAP contents. It
is presumed that once the needed organic HAP emission levels are established, other wood
building products facilities will work with their coating suppliers to reformulate surface coating
materials to comply with the NESHAP. Reformulation can be achieved in several ways, including
switching to one of the following: waterborne coatings, radiation-curable coatings, such as UV-
or EB-cured coatings, and other high-solids coatings as defined in Chapter 3. Also, using low- or
no-HAP solvents for thinning solvents and cleaning materials is another type of reformulation.
The HAP content of various coatings cannot be viewed in a vacuum. It is important to consider
the issue of organic HAP emissions versus VOC emissions in all reformulation scenarios.
Approximately 58 percent of the VOCs used as solvents in wood building products surface
coatings are also organic HAPs, as described in Chapter 3. The data show, however, that
reducing VOC content does not necessarily mean that HAP content will be reduced in a specific
coating. Many of the coatings have multiple solvent components, and if the coating manufacturer
chooses to reduce or eliminate non-HAP solvents, the organic HAP content would not change (or
may increase). Similarly, reductions in organic HAPs via substitution may not reduce the VOC
content either (i.e., lower-HAP coatings are not necessarily lower-VOC coatings). While there is
no direct correlation between reducing organic HAPs and VOCs in each specific coating, it is
believed that reducing VOCs overall will result in organic HAP emission reductions as well.
The approach for determining the MACT floor emission limits being considered for this industry
involves setting organic HAP emission limits for overall wood building products surface coating
operations. The overall facility organic HAP emission limits for both new or reconstructed and
existing affected sources are located in Table 4-8.
4-11
-------
^Table 4-8. Overall Facility Organic HAP Emission Limits By Subcategory
Model plant number
Number of facilities in database
Estimated number of facilities in industry
Number of facilities in MACT floor
HAP emission limit for new or reconstructed
affected sources (Ib HAP/gal solids)
HAP emission limit for existing affected
sources (Ib HAP/gal solids)
Model Plant Type
Doors and
windows
1
11
50
6
0.48
1.45
Flooring
2
5
50
4
0.00
0.78
Interior wall
paneling and
tileboard
3
6
15
5
0.04
1.53
Other
interior
panels
4
13
25
5
0.00
0.01
Exterior siding,
doorskins, and
miscellaneous
5
12
65
8
0.00
0.06
4.4 REFERENCES
1. Reeves, D., MRI, to Lluberas, L., EPA/CCPG and Sorrels, L., EPA/ISEG. December 18,
2000. Number of Major Sources Estimated to be Subject to the Wood Building Products
(Surface Coating) NESHAP
2. Threatt, B. and Reeves, D., MRI, to Lluberas, L., EPA/CCPG, December 22, 2000.
Determination of MACT Floors for the Wood Building Products Surface Coating
National Emission Standards for Hazardous Air Pollutants (NESHAP).
3. Reeves, D., MRI, to Lluberas, L., EPA/CCPG, June 28, 2000. Site Visit - ABTco,
Incorporated; Toledo, Ohio, Wood Building Products (Surface Coating) NESHAP.
4-12
-------
Chapter 5
Summary of Environmental and Energy Impacts
This chapter presents primary air, secondary environmental (air, water, and solid waste), and
energy impacts for existing major sources resulting from the control of HAP emissions under the
proposed standards for the wood building products (surface coating) source category. Due to
consolidation throughout the industry both before and after the proposed standards, there is not
expected to be any net growth within the wood building products surface coating industry within
the;next 5 years. All calculations and conclusions regarding environmental and energy impacts are
based on the MACT floors identified in Chapter 4, Model Plants and Control Options.
Since MACT for this industry primarily involves reformulation or selection of low- or no-HAP
coatings, environmental and energy impacts to the industry are greatly simplified. The primary air
impacts and secondary environmental impacts are discussed in sections 5.1 and 5.2, respectively.
There is minimal impact to energy consumption resulting from implementing the control option(s)
for existing major source wood building products surface coating facilities.
Add-on controls (i.e., oxidizers and adsorbers) for coating application lines and drying/curing
ovens, were initially considered for purposes of "above the floor" calculations. This control
option would have a significant affect on primary and secondary air impacts, water impacts, solid
waste impacts, energy, and cost impacts. For these reasons and the preliminary evaluation of
costs, the "above the floor" control option was found to be unfeasible (e.g., not cost effective) for
5-1
-------
any of the subcategories comprising the wood building products (surface coating) source
category.
5.1 PRIMARY AIR IMPACTS
Primary air impacts consist of the reduction in organic HAP emissions (from the baseline level)
that is directly attributable to the proposed standards. The proposed standards are expected to
reduce organic HAP emissions from existing wood building products surface coating facilities by
approximately 3,500 tons per year (ton/yr) [3,200 megagrams per year (Mg/yr)], or 61 percent,
from a baseline level of 5,600 ton/yr (5,100 Mg/yr). Summaries of the primary air impacts for
each subcategory associated with implementation of the proposed standards are listed in
Table 5-1.
Tables 5-2 through 5-6 present the baseline organic HAP emissions and the organic HAP
emissions that are expected after MACT, by subcategory, for each of the 44 major source
facilities and three synthetic minor source facilities. Tables 5-2 through 5-6 also present the
organic HAP emissions for the proposed standards. The organic HAP emissions in Table 5-1 are
estimated using the model plant average values and the MACT floor organic HAP emission limits
for each subcategory from Chapter 4 in Tables 4-1 and 4-8, respectively. Therefore, since the
totals from Table 5-1 represent the emissions from the estimated 205 major source facilities and
Tables 5-2 through 5-6 only represent the 47 database facilities, each subcategory has to be scaled
up or extrapolated to give the same results.
5-2
-------
Table 5-1. Summary of Primary Air Impacts - Existing Sources
Subcategory
Doors and windows'1
Flooring
Interior wall paneling and
tileboard
Other interior panels
Exterior siding, doorskins,
and miscellaneous
Total
Estimated
number of
facilities"
50
50
15
25
65
205
Baseline HAP
h
emissions
(tons)
2,608
356
1,576
278
841
5,659
HAP emissions
after MACP
(tons)
712
191
925
4
361
2,193
HAP emission reduction
(from baseline)
Tons/yr
1,896
165
651
274
480
3,466
Percent
73
46
41
99
57
61
The estimated number of U. S. facilities in the industry was determined using industry information. Toxic Release Inventory (TRI) data, and the
facilities/emissions information in the project database.
The baseline emissions for the entire industry were estimated by extrapolating the average emissions after control for each subcategory in the project
database as identified in Table 4-1 of Chapter 4. The extrapolation started with the number of major source facilities in the project database and
increased the emissions to account for the estimated total number of major source facilities in the industry.
c The HAP emissions after MACT for the entire industry were estimated by multiplying the emission limits for existing sources in Table 4-8 by the
average coating solids in Table 4-1 and then extrapolating to the estimated number of major sources in the entire industry. The HAP emissions
after MACT do not include any trace HAPs or trace metals (inorganic HAPs).
The window, door, and miscellaneous subcategory includes one facility with confidential business information (CBI). Since the HAP emissions
after MACT are based on average model plant solids usages, then the number does not include the solids usage for the one CBI facility.
Table 5^2. Summary of Doors and Windows Air Impacts
Blind
facility ID
A-l
A-2
A-3a
A-4
A-5
A-6
A-7
A-8
A-9
A-10
A-lla
Totals
Baseline HAP emissions
(tons)
10.06
56.21
26.51
62.16
298.78
17.05
1.65
95.28
3.17
0.06
2.89
573.82
HAP emissions
after MACT (tons)
3.71
5.98
3.98
57.44
23.23
12.84
1.65
43.43
3.17
0.03
2.89
158.35
Percent
reduction (%)
63
89
85
8
92
25
0
54
0
52
0
72
This facility is a synthetic minor source. Synthetic minor sources are used to calculate the MACT floor, but are not subject to the standard. ,
5-3
-------
Table 5-3. Summary of Flooring Air Impacts
Blind
facility ID
B-l
B-2
B-3
B-4
B-5
Totals
Baseline HAP
emissions (tons)
0.00
15.31
2.55
7.83
9.90
35.59
HAP emissions
after MACT (tons)
0.00
10.23
2.55
1.48
0.24
14.50
Percent
reduction (%)
0
33
0
81
98
59
Table 5-4. Summary of Interior Wall Paneling and Tileboard Air Impacts
Blind
facility ID
C-l
C-2
C-3
C-4
C-5
C-6
Totals
Baseline HAP emissions
(tons)
106.83
286.38
2.66
24.92
144.01
65.55
630.35
HAP emissions
after MACT (tons)
106.83
40.40
2.66
24.92
44.13
11.56
230.50
Percent
reduction (%)
0
86
0
0
69
82
63
5-4
-------
Table 5-5. Summary of Other Interior Panel Air Impacts
Blind
facility ID
D-l
D-2
D-3
D-4
D-5
D-6
D-7
D-8
D-9
D-10
D-ll
D-12
D-13
Totals
Baseline HAP emissions
(tons)
2.47
44.14
40.22
0.00
0.03
0.54
0.48
7.13
1.67
0.60
35.40
0.60
11.03
144.31
HAP emissions
after MACT (tons)
0.03
0.12
0.31
0.00
0.03
0.54
0.03
0.03
0.10
0.00
0.15
0.06
0.05
1.45
Percent
reduction (%)
99
100
99
0
0
0
95
100
94
99
100
89
100
99
5-5
-------
Table 5-6. Summary of Exterior Siding, Doorskin, and Miscellaneous Air Impacts
Blind
facility ID
E-l
E-2a
E-3
E-4
E-5
E-6
E-7
E-8 •
E-9
E-10
E-ll
E-12
Totals
Baseline HAP emissions
(tons)
6
7
3
5
3
1
54
20
51
0
1
3
155
HAP emissions
after MACT (tons)
6
7
3
3
3
1
24
12
6
0
1
1
67
Percent
reduction (%)
0
0
8
38
6
0
56
42
88
0
0
70
57
This facility is a synthetic minor source. Synthetic minor sources are used to calculate the MACT floor, but are not subject to the standard.
5-6
-------
5.2 SECONDARY ENVIRONMENTAL IMPACTS
Secondary environmental impacts consist of any adverse or beneficial environmental impacts other
than the primary air impacts described in Section 5.1. Secondary environmental impacts include
the following: (1) secondary air impacts, (2) water impacts, and (3) solid waste impacts. To
comply with the proposed standard, it is anticipated that most wood building products surface
coating operations will switch to low- or no-HAP coatings to reduce organic HAP emissions.
Therefore, secondary air, water, and solid waste impacts from switching to low- or no-HAP
coatings are expected to be minimal. A small number of wood building products surface coating
operations will continue to use existing add-on control equipment to reduce emissions. New add-
on control equipment is not expected to be a cost-effective alternative due to the high capital and
annual costs associated with control devices. Therefore, there should be no additional secondary
impacts due to add-on control devices.
5.2.1 Secondary Air Impacts
N
Secondary air impacts consist of: (1) generation of by-products from fuel combustion needed to
operate control devices and (2) reduction of VOC. Since there will be no new add-on control
devices implemented as part of the standard for either new or existing sources, there will be no
generation of by-products from fuel combustion needed to operate control devices. Secondary air
impacts also include the reduction of VOC emissions. The VOC compounds are precursors to
ozone. Emissions of organic HAP compounds that are also VOC may be reduced by the
implementation of the standards, but the amount of VOC reduction achieved by the standard has
not been quantified.
5-7
-------
5.2.2 Secondary Water Impacts
There are no direct impacts to water resulting from reformulation to low- or no-HAP coatings.
When higher solids coatings are utilized, less coating is used and the total amount of overspray
would be expected to be reduced since the total volume of coating solids will be applied. An
increased use of low- or no-HAP waterborne coatings may result in increased water discharge due
to the coating equipment being cleaned using water. However, the water impacts are expected to
be minimal.
5.2.3 Secondary Solid Waste Impacts
-v
Solid waste impacts are expected to be minimal. The pollutants produced from wood building
products surface coating operations are expected to consist mainly of volatilized solvents (i.e.,
organic HAP); therefore, very little paniculate matter or solid waste will be generated.
5.3 ENERGY IMPACTS
Energy impacts primarily consist of the fuel usage and electricity needed to operate control
devices (especially RTOs) that are used to comply with the proposed standards. New control
devices are not expected to be added as a result of the standard for either new or existing sources,
so there should be no additional energy impacts. Also, minimal energy impacts are associated
with the reformulation of existing higher HAP-content coatings to low- or no-HAP coatings.
5-8
-------
Chapter 6
Model Plant Control Costs
6.0 INTRODUCTION
As described in Chapter 4, Model Plants and Control Options, the project database contains
information from 44 major source facilities and three synthetic minor source facilities. The
44 major source facilities comprise approximately 20 percent of the estimated 205 major source
wood building products surface coating facilities in the United States. The model plants and
estimated control costs were developed as representative of the actual facilities comprising each
industry subcategory. This chapter describes the estimated costs of NESHAP compliance for all
facilities in the five industry subcategories.
There are two basic options for controlling organic HAP emissions: the use of low- or no-HAP
coatings, dictated by the MACT floor; or the use of an RTO, chosen as the "beyond the floor"
control option. Sections 6.1 through 6.9 detail the costs associated with low- or no-HAP
coatings. Sections 6.10 through 6.14 detail the costs associated with the "beyond the floor"
control option to control organic HAP emissions. Section 6.15 compares the costs of using low-
or no-HAP coatings with the costs of add-on controls (RTOs) and explains the reasoning for
choosing the pollution prevention alternative. Section 6.16 contains References.
Section 6.1 describes each of the components used in calculating total coating-related costs:
• Material costs;
• Recordkeeping and reporting; and
• Performance testing for add-on control deyice(s).
6-1
-------
After explaining the background for each calculated cost component, the specific coating cost
details for the five subcategories in the wood building products surface coating industry are
provided in Sections 6.2 through 6.6. Section 6.7 summarizes the cost effectiveness, or cost per
mass of organic HAP controlled, for each of the proposed subcategories and for the overall
industry. Section 6.8 shows the annual costs that will be required for the estimated major sources
in the industry to comply with the NESHAP requirements by using low- or no-HAP coatings.
Section 6.9 details the small business cost impact from using low- or no-HAP coatings.
Section 6.10 describes these components used in calculating RTO costs:
• Equipment costs for RTOs and permanent total enclosures;
• RTO maintenance costs;
• Recordkeeping and reporting costs;
• Computer equipment costs; and
• Performance testing for RTOs.
After explaining the background for each calculated cost component, the specific cost details for
the five subcategories in the wood building products surface coating industry are provided in
Section 6.11. Section 6.12 summarizes the cost effectiveness, or cost per mass of organic HAP
controlled, for each of the proposed subcategories and for the overall industry. Section 6.13
shows the annual costs that will be required for the estimated major sources in the industry to
comply with the NESHAP requirements by installing RTOs. Section 6.14 details the small
business cost impact of requiring RTO usage.
6.1 COST ESTIMATES USING LOW- OR NO- HAP COATINGS
6.1.1 Material Costs
The purpose of the wood building products (surface coating) NESHAP is to reduce organic HAP
emissions resulting from surface coating operations. It is expected that the format of the
NESHAP will limit the amount of organic HAP emitted relative to the volume of coating solids
applied during a calendar month. This monthly limit will then be used to calculate a 12-month
6-2
-------
rolling average that must be met by each affected facility. Most facilities will use low- or no-HAP
materials, while a few facilities will use existing add-on control devices to meet this requirement.
Cost estimates are not included in this chapter pertaining to facilities that may choose to use
existing add-on control devices rather than low- or no-HAP coatings.
To calculate the costs associated with low- or no-HAP coatings, some assumptions were made.
Having little or no information available from coating suppliers, an estimated average cost of
$20 per gallon (gal) of coating was used, along with the assumption that low- or no-HAP
coatings will cost an additional 10 percent. The coating usage at each facility was analyzed to
estimate the amount of higher HAP-containing coatings used by the facility in the baseline year of
1997. For purposes of this analysis, a higher HAP-containing coating is defined as one whose
organic HAP content per volume of solids (Ib HAP/gal solids) is greater than the MACT floor
organic HAP emission limit for the applicable facility subcategory. Costs were calculated using
the assumption that each facility will use the same total volume of coatings that were consumed in
the baseline year of 1997. Costs are based on a $22 per gal cost for low- or no-HAP coatings
compared to a $20 per gal cost for coatings with higher HAP content. Using the $2 per gal
differential, the coating cost is the incremental cost to the facility rather than a total material
investment.
For each of the five subcategories, there is a summary table that lists all costs associated with each
facility in the project database. These summaries are presented in Tables 6-5 through 6-9. For
each subcategory. facilities were classified as MACT floor facilities, synthetic minor facilities,
and/or small business facilities. Although used in determining the MACT floor limits for the
applicable subcategories, the three synthetic minor source facilities were not assigned any
compliance costs since they will not be required to comply with any of the NESHAP
requirements. If a major source facility has a calculated organic HAP emission level equal to or
lower than the emission limit for its subcategory, there are no associated material costs for the
facility. On the other hand, if a facility has a calculated organic HAP emission level above the
organic HAP-emission limit for the subcategory, there are material costs at a rate of $2 per gal of
6-3
-------
higher HAP-containing coating used. The total estimated cost for low- or no-HAP coatings is an
additional $22.1 million per year for the entire industry of 205 major source facilities.
6.1.2 Recordkeeping and Reporting Costs
6.1.2.1 Labor Costs
Since recordkeeping and reporting will be done on a continuous basis after the compliance date,
the associated costs are considered annual costs. Recordkeeping and reporting labor
requirements were calculated based on assumed activities and time required for each activity. The
required compliance activities were listed and assigned a time estimate, based on the difficulty of
the task and the following assumptions. For all activities, regular work hours are assumed to be 2
shifts per day, 5 days per week, and 50 weeks per year. Based on database information, a typical
facility has three separate coating lines, and uses nine coatings, one thinning solvent, and one
cleaning solvent in surface coating operations. Using an average of all database facilities, there
are 37 coating employees for a typical facility.
The following paragraphs contain a detailed description of the labor requirements for
recordkeeping and reporting activities. Most of the activities are related to the recordkeeping
aspect of the NESHAP. First, the technical contact, most likely an environmental or process
engineer, must decide the best way to compile the coating data and calculate the related organic
HAP emissions. This typically will involve a spreadsheet where all relevant coating information is
contained and used to calculate the organic HAP emissions for each coating line. Once the
engineer knows what information is required to calculate the coating-related emissions for the
facility, all coating personnel must be trained to gather the required information. The first data-
gathering step occurs at the coating line itself. Coating operators or paint room personnel will
track the amount of coating used during each shift on each line. Material safety data sheets
(MSDS), technical data sheets, and/or HAP data sheets are consulted for the organic HAP
content, solids content, and density of each coating. When this data has been collected, the
clerical department enters all data into the spreadsheet. The spreadsheet is used to calculate the
total coating line emissions during each shift, day, and month. On a weekly basis, the
environmental engineer checks the data for entry errors and for compliance trends or issues.
6-4
-------
Approximately once every three months, the engineer will have to make adjustments to the
coating process to maintain the monthly compliance limits. The engineer will also be in charge of
coordinating and maintaining the data that is transferred between departments each day.
Each facility will be required to comply with the overall organic HAP emission limit on a monthly
basis, and reporting will be done semiannually. The report will include the monthly totals, an
overall average organic HAP emission rate, and a compliance status report. Depending on the
facility emissions, there will be either a report of no exceedances or a report of deviations.
Once the labor hour requirements were estimated, labor rates were calculated using 1997 Bureau
of Labor Statistics data for Standard Industrial Classification (SIC) code groupings 242, 243, and
249. Using the affected SIC codes of 2426, 2429, 2431, 2435, 2436, 2439, 2493, and 2499, SIC
code groups 242, 243, and 249 were represented two times, four times, and two times,
respectively. To get a weighted average for technical, managerial, clerical, and coating line staff,
the* sum of the labor rates was divided by eight. The base labor rate was then scaled up to include
overhead, profit, and all employee benefits. The fully burdened labor rate was calculated by
summing (a) the base labor rate, and (b) 110 percent of the base labor rate. The hourly rates used
for a technical contact, a managerial supervisor, a clerical assistant, and a coating/painting/
spraying machine operator, were $50.33, $59.75, $21.80, and $20.65, respectively. These labor
rates are summarized in Table 6-1.
Using the individual labor rates and the labor hours for recordkeeping and reporting, the average
annual cost is $26,500 for each major source facility. The totals and specific details are
summarized in Table 6-2. For the entire industry of 205 major source facilities, recordkeeping
and reporting labor is estimated to cost $5.4 million annually.
6-5
-------
Table 6-1. Labor Rates for Recordkeeping and Reporting
Labor Type
Technical Labor Rate ($/hr)
Management Labor Rate ($/hr)
Clerical Labor Rate ($/hr)
Coating, Painting and Spraying Machine Operator Labor Rate ($/hr)
SIC Group
242"
$25.19
$32.08
$10.29
$10.96
243b
$23.31
$26.15
$10.61
$9.63
249C
$24.06
$29.42
$10.01
$9.11
Average
Labor
Rate
$23.97
$28.45
$10.38
$9.83
1 10% of
Average
Labor
Rate
$26.36
$31.30
$11.42
$10.82
Total
Labor
Rated
$50.33
$59.75
$21.80
$20.65
a SIC Group 242 represents SIC Codes 2426 and 2429.
1 SIC Group 243 represents SIC Codes 2431,2435, 2436, and 2439.
c SIC Group 249 represents SIC Codes 2493 and 2499.
d Total Labor Rate is the sum of the Average Labor Rate and 110% of the Average Labor Rate.
ON
ON
-------
6.1.2.2 Computer Equipment Costs
As detailed in the previous section, recordkeeping and reporting costs assume the use of a
computer and software for tracking the coating usages for each facility. Assumptions were made
concerning the cost of computer equipment and the number of respondents required to buy the
equipment. A cost of $2,000 for the equipment was estimated for the computer, associated
accessories, and the spreadsheet software. Facilities using more than 100,000 gal per year (gal/yr)
were excluded from the requirement because of the assumption that computer equipment is
already available. Of the 44 major sources, an estimated 25 may require computer equipment.
Scaling the number to include the estimated industry of 205 major sources, there will be an
estimated 119 facilities requiring computer equipment. Assuming that a new computer will be
bought every five years and the interest rate is 7 percent, the capital recovery factor is 0.2439.
Multiplying the capital investment cost of $2,000 by the capital recovery factor yields an
annualized computer equipment cost of $488 per facility, bringing the total industry cost for
computer equipment to $58,000. These findings are summarized in Table 6-3.
The recordkeeping and reporting costs are greatly influenced by the labor costs, rather than by the
cost of computer equipment. The combined total for recordkeeping and reporting is $5.5 million.
The two items are summarized in Table 6-4.
6.1.3 Performance Testing Costs for Add-On Control Devices
There are 44 major source facilities in the project database, including 3 facilities that use add-on
control devices to control organic HAP emissions from surface coating operations. In order to
verify that the add-on control devices are performing at adequate levels of control, performance
testing is required for each add-on control device. For purposes of costing, it was estimated that
each test would require 240 hours from a trained contractor at a labor rate of $80 per hour. For
facilities with multiple add-on control devices, the performance testing was costed accordingly.
Under normal circumstances, this testing will be performed every five years, so the costs were
annualized using a 5-year equipment life and an interest rate of 7 percent. The resulting capital
recovery factor is 0.2439 and the annualized cost for performance testing is $4,683 per control
device. For the 3 database facilities using add-on control devices, the total annualized cost is
6-7
-------
$65,560 per year. Assuming that approximately 14 of the 205 major source facilities have
existing add-on control devices and scaling the figure accordingly, performance testing will cost
an estimated $256,248 per year.
6-8
-------
Table 6-2. Recordkeeping and Reporting Labor Requirements
4
Burden item
1 . Applications
2. Surveys and studies
3. Reporting requirements
A. Read regulation
B. Apply for waiver
C. Required activities
Technical
Training of coating-related personnel each year
Set-up and maintain coating data spreadsheet for
regulation compliance
Coordinate purchasing, operations and clerical for
information transfer each month
Check spreadsheet for data entry errors weekly
Compile and maintain records of coatings data
each week
Using compiled data, adjust process to comply
with standard every quarter
Clerical
Enter data into spreadsheet to tabulate
information each day
Operations
Track coating usage in spreadsheet or log book
each shift
D. Create information
E. Gather existing information
(A)
Person -
hours per
occurrence
N/A
N/A
(B)
Number of
occurrences
per year
(C)
Person-
hours
per
respondent
per year
(C = A x B)
(D)
Respondents
per year
(E)
Technical
person-
hours
per year
(E = C x D)
(F)
Management
person-hours
per year
(F = Ex
0.05)
(G)
Clerical
person-
hours
per year
(G = Ex
0.1)
(H)
Cost,
$'
4
ff
1
1
4
6
205"
2d
820
12
41
1
82
1
45,508
666
4
4
1
1
I.5C
2
4C
1
12
50'
50'
4
16
4
12
50
75
8
205
205
205
205
205
205
3,280
820
2,460
10,250
15,375
1,640
164
41
123
513
769
82
328
82
246
1,025
1,538
164
182,032
45,508
136,524
568,849
853,274
91,016
lg
250" '
250
205
0
0
51,250
1,117,250
1'
Incl. in 3B
Incl. in 3B
500"
500
205
102,500
0
0
2,116,625'
0
0
-------
Table 6-2. Continued
Burden item
F. Write semi-annual report
Write compliance status report
Write performance test report
. Report of no exceedances
Write report of excess emissions
Total recurrent burden and cost
Average recurrent burden and cost oer facility:
(A)
Person-
hours per
occurrence
(B)
Number of
occurrences
per year
(C)
Person-
hours
per
respondent
per year
(C = A x B)
(D)
Respondents
per year
(E)
Technical
person-
• hours
per year
(E = C x D)
(F)
Management
person-hours
per year
(F = Ex
0.05)
(G)
Clerical
person-
hours
per year
(G = Ex
0.1)
(H)
Cost,
$'
4*
16
8L
16C
2
0.20"
2
2
8
3
16
32
203m
14"
203m
2"
1,624
45
3,248
64
142,135
693
81
2
162
3
1,982
10
162
4
325
6
55,213
269
90,128
2,486
180,256
3,552
5,433,674
26.506
I
)—»
o
Costs are based on the following hourly rates: technical at $50.33, management at $59.75, and clerical at $21.80. The composite hourly labor rate is $55.50/hr (50.33 + 0.05 x 59.75 + 0.1 x21.80 =
55.50).
'Assumes all 205 major source facilities will read the regulation.
From BSD manual Table 3 "Burden of NSPS and NESHAP Notification Reports, Excess Emission Reports and Recordkeeping."
Assumes 1 percent of 205 major source facilities will apply for a waiver.
Assuming an average of 37 coating employees, training will occur quarterly with 9 trainees per session.
Assumes 50 weeks per year.
Assumes 11 coatings per line and 3 lines per facility with 2 shifts, requiring 1 minute per entry.
Assumes 50 weeks per year and 5 days per week.
Assumes clerical instead of technical labor rate for data entry. (G= C x D)
Assumes 11 coatings per line and 3 lines per facility, requiring 2 minutes per entry per shift.
Assumes 2 shifts per day, 5 days per week, and 50 weeks per year.
Cost is based on a Coating, Painting and Spraying Machine Operator weighted labor rate of $20.65.
Assumes 99 percent of 205 major source facilities will be in compliance.
Assumes one test every 5 years or 0.20 test reports per year.
Assumes 3 of every 44 (14 of 205) major source facilities will use add-on control devices to comply with the NESHAP.
Assumes 1% of 205 major source facilities will be out of compliance.
-------
Table 6-3. Computer Equipment Cost Summary
Database facilities requiring
computer equipment
Number of major sources in
database
Estimated major sources in
industry1
Estimated number of major
sources requiring computer
equipment
Estimated cost to industry
Doors and
windows
6
9
50
33
$16,260
Flooring
5
5
50
50
$24,390
Interior wall
paneling and
tileboard
1
6
15
3
$1,220
Other
interior
panels
11
13
25
21
$10,319
Exterior siding,
doorskins, and
miscellaneous
2
11
65
12
$5,765
Totals
25
44
205
119
$57,953
Table 6-4. Summary of Recordkeeping and Reporting Costs
Labor for entire estimated
industry
C6mputer equipment for
entire estimated industry
Total
Doors and
windows
$1,325,000
$16,260
$1,341,260
Flooring
$1,325,000
$24,390
$1,349,390
Interior wall
paneling and
tileboard
$397,500
$1,220
$398,720
Other
interior
panels
$662,500
$10,319
$672,819
Exterior siding,
doorskins, and
miscellaneous
$1,722,500
$5,765
$1,728,265
Totals
$5,432,500
$57,953
$5,490,453
6.2 DOORS AND WINDOWS (MODEL PLANT 1)
There are 9 major sources and two synthetic minor source facilities in the project database that
coat doors and windows. Only one facility uses add-on control devices to control emissions from
coating operations. The controlled facility has four add-on control devices, but will still be
required to invest in low- or no-HAP coatings.
Using the total annual costs for the 9 major source facilities in the project database (see
Table 6-5) and the assumption that there are an estimated 50 major sources1 in the doors and
windows subcategory, the total annual costs for the subcategory were calculated. The total
annual cost to the subcategory is estimated to be $7.6 million.
6-11
-------
6.3 FLOORING (MODEL PLANT 2)
There are five major source flooring facilities in the project database. The flooring subcategory
has only one facility in the project database that uses an add-on control device to control organic
HAP emissions from surface coating operations. Since this facility meets the proposed MACT
floor limit for this subcategory, there are no related material costs.
Using the total annual costs for the five major source facilities in the project database and the
assumption that there are 50 major sources1 in the flooring subcategory, the total annual costs for
this subcategory are shown in Table 6-6.
6.4 INTERIOR WALL PANELING AND TILEBOARD (MODEL PLANT 3)
The interior wall paneling and tileboard subcategory contains six major sources in the project
database, only one of which uses add-on control devices. That particular facility reported using
nine add-on control devices (thermal incinerators) to control coating-related organic HAP
emissions.
Using the total annual costs for the six major source facilities in the project database and the
assumption that there are 15 major sources1 in the subcategory, the total annual cost to the
subcategory is estimated to be $1.88 million as summarized in Table 6-7.
6.5 OTHER INTERIOR PANELS (MODEL PLANT 4)
There are 13 other interior panel major source facilities in the project database used in
determining the MACT floor organic HAP emission limit. None of these facilities use add-on
control devices to control organic HAP emissions from surface coating operations.
Using the total annual costs for the 13 major source facilities in the project database (summarized
in Table 6-8) and the assumption that there are 25 major sources1 in the entire subcategory, the
total annual costs for the 25 facilities were calculated. The costs for this subcategory are
estimated to be $1.5 million.
6-12
-------
Table 6-5. Doors and Windows (Model Plant 1) MACT Costs
Total
Floor
facility?
6
Synthetic
minor?
2
Small
business?
6
Number
of APCDs
4
Performance
testing for
control
device(s) ($)
18,731
Total coating
usage (gal)
Coatings usage
above emission
limit (gal)
Annual
material costs
($)
Computer
equipment
costs ($)
2.927
Annual
R&R
costs ($)
238.500
Annual
costs ($)
$1.374,172
a Since one of the 11 facilities has associated CBI, only the totals for this subcategory are shown. The annual cost includes the costs from the CBI facility, but no CBI is
shown in this table.
Table 6-6. Flooring (Model Plant 2) MACT Costs
Blind
facility
B-l
B-2
B-3
B:4
B-5
Total '
Floor
facility?
Yes
Yes
Yes
Yes
Yes
5
Synthetic
minor?
0
Small
business?
0
Number
of APCDs
1
1
Performance
testing for
control
dcvicc(s) {$)
0
0
4,683
0
0
$4,683
Total coating
usage (gal)
7,946
37,416
19,273
6,628
1,348
72,61 1
Coatings usage
above emission
limit (gal)
0
12,284
6,890
3,041
1,348
23,563
Annual
material costs
($)
0
0
0
6,082
2,696
$8,778
Computer
equipment
costs ($)
488
488
488
488
488
$2.440
Annual
R&R
costs ($)
26,500
26,500
26,500
26,500
26,500
$132,500
Annual
costs ($)
26,988
26,988
31,671
33,070
29,684
$148,401
U>
Table 6-7. Interior Wall Paneling and Tileboard (Model Plant 3) MACT Costs
Blind
facility
C-l
C-2
C-3
C-4
C-5
C-6
Total
Floor
facility?
Yes
„
Yes
Yes
Yes
Yes
3
Synthetic
minor?
0
Small
business?
Yes
1
Number
of APCDs
9
9
Performance
testing for
control
device(s) ($)
42,144
0
0
0
0
0
$42,144
Total coating
usage (gal)
320,440
154,127
298,173
249,463
125,246
30,513
1,177,962
Coatings Usage
above emission
limit (gal)
51,013
144,655
4,791
69,297
99,645
30,513
399.914
Annual
material costs
($)
0
289,310
0
0
199,290
61,026
$549,626
Computer
equipment
costs ($)
0
0
0
0
0
488
$488
Annual
R&R
costs ($)
26,500
26,500
26,500
26,500
26,500
26,500
$159.000
Annual
costs ($)
68,644
315,810
26,500
26,500
225,790
88,014
$751.258
-------
Table 6-8. Other Interior Panels (Model Plant 4) MACT Costs
Blind
facility
D-l
D-2
D-3
D-4
D-5
D-6
D-7
D-8
D-9
D-10
D-ll
D-12
D-l 3
Total
Floor
facility?
Yes
Yes
Yes
Yes
Yes
5
Synthetic
minor?
0
Small
business?
0
Number
ofAPCDs
0
Performance
testing for
control
devicc(s) ($)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Total coating
usage (gal)
13,570
70,832
93,101
7,776
302,758
555,524
12,028
21,243
74,606
1,103
33,413
27,285
18,155
1.231,394
Coatings usage
above emission
limit (gal)
11,406
37,074
79,130
0
0
1,800
1,065
16,704
11,351
' 761
20,117
27,285
13,523
220,216
Annual
material costs
($)
22,812
74,148
158,260
0
0
0
2,130
33,408
22,702
1,522
40,234
54,570
27,046
436,832
Computer
equipment
costs ($)
488
488
488
488
0
0
488
488
488
488
488
488
488
$5,368
7
Annual R & R
costs ($)
26,500
26,500
26,500
26,500
26,500
26,500
26,500
26,500
26,500
26,500
26,500
26,500
26,500
$344.500
. Annual
costs ($)
49,800
101,136
185,248
26,988
26,500
26,500
29,118
60,396
49,690
28,510
67,222
81,558
54,034
$786,700
Table 6-9. Exterior Siding, Doorskins, and Miscellaneous (Model Plant 5) MACT Costs
Blind
facility
E-l
E-2
E-3
E-4
E-5
E-6
E-7
E-8
E-9
E-10
E-ll
E-l 2
Total
Floor
facility?
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
8
Synthetic
minor?
Yes
1
Small
business?
Yes
1
Number
of'
APCDs
0
Performance
testing for
control
device(s) ($)
0
0
0
0
0
0
0
0
0
0
0
0
0
Total coating
usage (gal)
468,792
146,145
219,551
238,249
237,238
188,132
1,992,450
938,766
454,600
93,311
207,094
58,541
5,242,869
Coatings usage
above emission
limit (gal)
62,717
48,647
208,539
237,311
0
0
385,574
72,703
186,701
0
0
58,541
1,260,733
Annual material
costs ($)
0
0
417,078
474,622
0
0
771,148
145,406
373,402
0
0
117,082
2,298,738
Computer
equipment
costs ($)
$0
$0
$0
$0
$0
$0
$0
$0
$0
$488
$0
$488
$976
Annual
R&
costs ($)
$26,500
$0
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$29L500
Annual
costs ($)
$26,500
$0
$443,578
$501,122
$26,500
$26,500
$797,648
$171,906
$399,902
$26,988
$26,500
$144,070
$2,591,214
-------
6.6 EXTERIOR SIDING, DOORSKINS, AND MISCELLANEOUS (MODEL PLANT 5)
There are 12 exterior siding and doorskin facilities in the project database used to determine the
MACT floor organic HAP emission limit. Of these, 11 are considered major sources of organic
HAP emissions and one facility is a synthetic minor source. None of these facilities use add-on
control devices to control organic HAP emissions from surface coating operations.
Using the total annual costs for the 11 major source facilities in the project database (summarized
in Tables 6-9) and the assumption that there are 65 major sources1 in the entire subcategory, the
total annual costs for the 65 facilities were calculated. The costs for this subcategory are
estimated to be $15.3 million.
6.7 COST EFFECTIVENESS OF LOW- OR NO-HAP COATINGS
Cost effectiveness is the cost per mass of organic HAP controlled and is an indicator of the
overall effectiveness of MACT implementation. The data is presented in Table 6-10 for each
model plant (subcategory). Table 6-10 summarize the costs incurred by each subcategory, such
as recordkeeping and reporting costs, computer equipment costs, material costs, and performance
testing costs. The emission reductions shown in the tables are presented in Chapter 5, specifically
Table 5-1. To calculate the cost effectiveness of the MACT implementation, the total costs (in
dollars) were divided by the anticipated organic HAP reductions (in tons per year or Mg per
year).
Table 6-10 summarizes the cost effectiveness of the NESHAP. The cost effectiveness data ranged
from $2,900 to $32,000/ton ($3,200 to $35,000/Mg) for the five subcategories and averaged
$8,000/ton ($8,800/Mg) for the overall industry.
6.8 ANNUAL COST FOR LOW- OR NO-HAP COATINGS
The annual costs for using the low- or no-HAP coatings option total $27.8 million for the entire
industry of 205 major source facilities. Recordkeeping and reporting costs contribute
6-15
-------
$5.4 million; computer costs contribute $58,000; performance testing contributes $256,000; and
coating costs contribute $22.1 million.
6.9 SMALL BUSINESS IMPACT (LOW- OR NO-HAP COATINGS)
Small businesses are defined as companies that have 500 or fewer corporate employees. There
are 12 companies identified as small businesses in the project database. Five of the companies are
designated as area sources, according to Title V classification. Therefore, seven small businesses
are included in the total population of facilities used in determining MACT. Only four of those
facilities are considered major sources of organic HAP emissions and will be required to meet the
NESHAP requirements; 3 facilities are considered synthetic minor sources. The annual cost for
the four facilities is approximately $471,000 (combined). Based on the project database, an
estimate on the number of major source small businesses for the entire source category has been
determined to be approximately 20, therefore, the total estimated cost to small business major
sources is $2.4 million.
Information on the seven small business facilities is provided in Tables 6-5, 6-7, and 6-9. Due to
the confidential business information contained in Table 6-5, the five specific small business
facilities are not identified.
6-16
-------
Table 6-10. Cost Effectiveness of MACTa
MACT implementation
Emission reductions
Total organic HAP emission
reductions (ton/yr)
Total organic HAP emission
reductions (Mg/yr)
Industry Costs
Materials ($)
Recordkeeping and reporting ($)
Computer equipment ($)
Performance testing ($)
Total cost for industry ($)
Cost effectiveness ($/ton)
Cost effectiveness ($/Mg)
Doors and
windows
1,896
1,720
6,188,970
1,325,000
16,259
104,060
7,634,289
4,027
4,438
Model plants
Flooring
165
150
87,780
1,325,000
24,389
46,827
1,483,996
8,994
9,914
Interior wall
paneling and
tileboard
(class 1
hardboard)
651
591
1,374,065
397,500
1,219
105,361
1,878,145
2,885
3,180
Other
interior
panels
274
249
840,062
662,500
10,318
0
1,512,880
5,521
6,086
Exterior
siding,
doorskins, and
miscellaneous
480
435
13,583,452
1,722,500
5,765
0
1-5,311,717
31,899
35,163
Totals
3,466
3,144
22,074,329
5,432,500
57,950
256,248
27,821,027
8,027
8,848
Sample Calculation for Doors and Windows: Cost Effectiveness = Total cost for industry / Total organic HAP emission reductions ($6,188,970 /
1896 tons = $4,027 /ton).
6-17
-------
6.10 "BEYOND THE FLOOR" COST ESTIMATES
"Beyond the floor" options are other methods of organic HAP control that are more stringent
than the MACT floor dictates. In this case, a regenerative thermal oxidizer (RTO) was chosen as
the "beyond the floor" option required to comply with the wood building products (surface
coating) NESHAP. This choice allows for a high level of organic HAP reduction.
For new or reconstructed sources, most of the organic HAP emission limits are 0.00 kg HAP/liter
of solids (Ib HAP/gallon solids). These limits will achieve 100 percent or nearly 100 percent
organic HAP emission reductions. Therefore, no control technologies are available as a "beyond
the floor" option fdr controlling organic HAP from new or reconstructed sources.
"Beyond the floor" costs for each of the five subcategories are summarized in Tables 6-11
through 6-15.
6.10.1 Equipment Costs
Equipment costs for RTOs are based on the dryer exhaust data reported by each facility. For the
facilities that did not supply dryer exhaust information, an average value was calculated from the
supplied information. Whenever an average value was used, the value is shown in bold type on
the summary tables. The total capital investment (TCI) was calculated using a complicated cost
model that accounted for equipment purchase, foundation, installation, labor, engineering, and
construction. Each facility was assumed to require one RTO except in the following instances:
• Facility E-2 in the Exterior Siding, Doorskins, and Miscellaneous subcategory had
such high dryer exhaust flow rates that it was more cost efficient to assume three
RTOs for the facility.
• If a facility had a Title V classification of synthetic minor, RTOs were not required
and TAC was zero.
• Facilities that were classified as Title V major sources but had no coating line
organic HAP emissions were also not required to purchase an RTO.
6-18
-------
Total capital investment costs included a cost for permanent total enclosures (PTEs). These are
enclosures built around an emission source that ensure 100% of organic HAP emissions are
captured. For each facility that was not capturing 100% of organic HAP emissions, the costs
were estimated at $500,000. The total capital investment costs were annualized assuming a five
year equipment life and an interest rate of 7%. These assumptions result in a capital recovery
factor of 0.2439.
For the entire industry of 205 estimated major sources, the annualized capital investment costs for
"beyond the floor" options is estimated to be $60.5 million.
6.10.2 Operating Costs
Operating costs for RTOs were calculated using the same cost model as the capital costs.
Operating costs include maintenance and labor costs, electricity, auxiliary fuel, overhead,
administrative charges, taxes, and insurance. These, costs are already annualized in the
spreadsheets.
If a facility had a Title V classification of synthetic minor, RTOs were not required and the
operating costs were zero. Facilities that were classified as Title V major sources, but had no
coating line organic HAP emissions, were also given a zero operating cost.
For the entire industry of 205 major sources, the total RTO operating costs are estimated to be
$66.4 million.
6.10.3 Recordkeeping and Reporting Costs
Recordkeeping and reporting costs associated with RTOs were assumed to be the same as for
low- or no-HAP coating usage. In order to calculate the emission rate, each facility will still be
required to track the amount of coatings used, the organic HAP content of the coatings, and the
solids content of the coatings. In addition, each facility will be required to track the fraction of
the emission stream that is being controlled ^nd the resulting destruction efficiency. These
6-19
-------
additional tasks are not expected to add significantly to the recordkeeping and reporting cost per
facility. All assumptions that contributed to the $26,500 cost per facility are contained in
Section 6.1.2.1. For the entire industry of 205 estimated major sources, this is assumed to be
$5.4 million.
6.10.4 Computer Equipment Costs
Computer equipment was assumed for each facility that used less than 100,000 gallons of coatings
yearly. Of the 44 major sources, an estimated 26 may require computer equipment. Scaling the
number to include the estimated industry of 205 major sources, there will be an estimated 126
facilities requiring computer equipment. Assuming that a new computer will be bought every
5 years and the interest rate is 7 percent, the capital recovery factor is 0.2439. Multiplying the
capital investment cost of $2,000 by the capital recovery factor yields an annualized computer
equipment cost of $488 per facility, bringing the total industry cost for computer equipment to
$59,000. These costs are summarized in Table 6-3.
6.10.5 Performance Testing Costs
In order to verify that the add-on control devices are performing at adequate levels of control,
performance testing is required for each add-on control device. For purposes of costing, it was
estimated that each test would require 240 hours from a trained contractor at a labor rate of
$80 per hour. For facilities with multiple add-on control devices, the performance testing was
costed accordingly. Under normal circumstances, this testing will be performed every 5 years, so
the costs were annualized using a five year equipment life and an interest rate of 7 percent. The
resulting capital recovery factor is 0.2439 and the annualized cost for performance testing is
$4,683 per control device. For the entire industry consisting of 205 estimated major sources,
performance testing is estimated to cost $1.1 million.
6-20
-------
6.11 "BEYOND THE FLOOR" COST ESTIMATES
6.11.1 Doors and Windows Subcategory
"Beyond the floor" cost estimates are given in Table 6-11. Costs were estimated for each of the
10 major source facilities and one synthetic minor facility in the database. Assuming that there are
approximately 50 major source facilities in the subcategory, the estimated annual cost impact is
approximately $30.8 million.
6.11.2 Flooring Subcategory
"Beyond the floor" cost estimates are given in Table '6-12 for the flooring facilities. Costs were
estimated for each of the five major source facilities in the database. Assuming that there are
approximately 50 major source facilities in the subcategory, the estimated annual cost impact is
approximately $9.2 million.
6.11.3 Interior Wall Paneling and Tileboard Subcategory
"Beyond the floor" cost estimates are given in Table 6-13 for each of the six major source interior
wall paneling and tileboard facilities in the database. Assuming that there are approximately 15
major source facilities in the subcategory, the estimated annual cost impact is approximately
$8.8 million.
6.11.4 Other Interior Panels Subcategory
"Beyond the floor" cost estimates are given in Table 6-14 for all other interior panel facilities.
Costs were estimated for each of the 13 major source facilities in the database. Assuming that
there are approximately 25 major source facilities in the subcategory, the estimated annual cost
impact is approximately $13.4 million.
6.11.5 Exterior Siding, Doorskins, and Miscellaneous Subcategory
"Beyond the floor" cost estimates are given in Table 6-15 for those facilities producing exterior
siding, doorskins, and miscellaneous products. Costs were estimated for each of the 11 major
6-21
-------
source facilities and one synthetic minor facility in the database. Assuming that there are
approximately 65 major source facilities in the subcategory, the estimated annual cost impact is
approximately $71.4 million.
6.12 COST EFFECTIVENESS FOR "BEYOND THE FLOOR" OPTION
Cost effectiveness is summarized in Table 6-16. Organic HAP reductions were calculated
assuming a capture efficiency of 100% (while using a PTE) and a destruction efficiency of
90 percent. Table 6-16 summarizes the cost effectiveness.
The cost effectiveness ranges from $6,200 to $91,000 per ton of organic HAP reduced and
averages $25,300 per ton of organic HAP reduced.
6.13 ANNUAL COSTS FOR "BEYOND THE FLOOR" OPTION
The annual costs for installing and maintaining RTOs, chosen as the "Beyond the floor" option,
total $133.5 million for the entire industry of 205 major source facilities. Recordkeeping and
reporting contributes $5.4 million; computer costs contribute $58,000; performance testing
contributes $1.1 million; annualized capital costs contribute $60.5 million; and annual operating
costs contribute $66.4 million.
6.14 SMALL BUSINESS IMPACT ("BEYOND THE FLOOR" OPTION)
For the four major source small businesses in the database, the total annual cost is approximately
$2 million to purchase, install, and maintain RTOs. Assuming that there are 20 small business
facilities in the entire industry, the impact to all small businesses in the wood building products
surface coating industry is $10.6 million.
6-22
-------
Table 6-11. "Beyond the Floor" Cost Options for Doors and Windows3
Blind-
facility
ID
A-1 «.
A-2.
A-3
A-4
A-5
A-6
A-7
A-8
A-9
A-10
A-ll
Totals
Synthetic
minor?
Yes
Yes
2
Small
business?
Yes
Yes
Yes
Yes
Yes
5
Number
of APCDs
1
1
1
4
1
1
1
1
1
' 1
0
13
TCI (RTO)
$1,526,361
$955,956
$0
$500,000
$1,157,646
$1,570,544
$935,075
$1,688,021
$1,076,970
$941,057
$0
Annualized
TCI (RTO)
$372,265
$233,149
$0
$121,945
$282,339
$383,041
$228,056
$411,693
$262,663
$229,515
$0
$2,524,666
Operating
costs (RTO)
$447,657
$237,367
$0
$0
$311,224
$464,171
$229,744
$508,302
$281,629
$248,009
$0
$2,728,103
Performance
testing for
control
device(s)
$4,683
$4,683
$0
$18,731
$4,683
$4,683
$4,683
$4,683
$4,683
$4,683
$0
$56,195
Computer
equipment
costs
$488
$488
$0
$0
$0
$488
$488
$0
$488
$488
$0
$2,928
Annual
R & R costs
$26,500
$26,500
$0
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$0
$238,500
Annual Costs
$851,593
$502,187
$0
$167,176
$624,746
$878,883
$489,471
$951,178
$575,963
$509,195
$0
$5,550,392
to
u>
' Values in bold type indicate that an average value was used.
-------
Table 6-12. "Beyond the Floor" Cost Options for Flooring
r? o
Blind
facility
ID
B-l
B-2
B-3
B-4
B-5
Total
Synthetic
minor?
0
Small
business?
0
Number
of APCDs
0
1
1
1
1
4
TCI (RTO)
$0
$938,477
$0
$312,826
$312,826
Annualized
TCI (RTO)
$0
$228,886
$0
$76,295
$76,295
$381,476
Operating
costs (RTO)
$0
$230,985
$0
$76,995
$76,995
$384,975
Performance
testing for
control
device(s)
$0
$4,683 -
$4,683
$4,683
$4,683
$18,732
Computer
equipment
costs
$488
$488
$488
$488
$488
$2,440
Annual
R & R costs
$26,500
$26,500
$26,500
$26,500
$26,500
$132,500
Annual Costs
$26,988 .
$491,542
$31,671
$184,961
$184,961
$920,123
!
§
c.
f.
60
N—<
a
^
!
' Values in bold type indicate that an average value was used.
Table 6-13. "Beyond the Floor" Cost Options for Interior Wall Paneling and Tileboard"
Blind
facility
ID
C-l
C-2
C-3
C-4
C-5
C-6
Total
Synthetic
minor?
0
Small
business?
0
Number
of APCDs
9
1
1
1
1
1
14
TCI (RTO)
$500,000
$1,109,707
$1,285,369
$1,109,707
$1,688,089
$965,368
Annualized
TCI (RTO)
$121,945
$270,647
$313,490
$270,647
$411,709
$235,444
$1,623,882
Operating
costs (RTO)
$0
$276,844
$358,243
$276,844
$508,328
$240,805
$1,661,064
Performance
testing for
control
device(s)
$42,144
$4,683
$4,683
$4,683
$4,683
$4,683
$65,559
Computer
equipment
costs
$0
$0
$0
$0
$0
$488
$488
Annual
R & R costs
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$159,000
Annual Costs
$190,589
$578,674
$702,916
$578,674
$951,220
$507,920
$3,509,993
f
*-••
n>
I
•
to
g
" Values in bold type indicate that an average value was used.
-------
Table 6-14. "Beyond the Floor" Cost Options for Other Interior Panels8
Blind
facility
ID
D-l
D-2
D-3
D-4
D-5
D-6
D-7
D-8
D-9
D-10
D-ll
D-12
D-13
Total
Synthetic
minor?
Small
business?
Number
of
APCDs
1
1
1
0
1
1
1
1
1
1
1
1
1
12
TCI (RTO)
$1,023,186
$986,317
$1,009,740
$0
$986,317
$1,426,565
$977,806
$986,317
$1,211,430
$986,317
$1,322,023
$919,787
$986,317
Annual ized
TCI (RTO)
$249,546
$240,554
$246,266
$0
$240,554
$347,926
$238,478
$240,554
$295,456
$240,554
$322,429
$224,327
$240,554
$3,127,198
Operating
costs (RTO)
$261,939
$262,719
$257,021
$0
$262,719
$410,504
$245,348
$262,719
$330,997
$262,719
$371,779-
$224,165
$262,719
$3,415,348
Performance
testing for control
device(s)
$4,683
$4,683
$4,683
$0
$4,683
$4,683
$4,683
$4,683
$4,683
$4,683
$4,683
$4,683
$4,683
$56,196
Computer
equipment
costs
- $488
$488
$488
$488
$0
$0
$488
$488
$488
$488
$488
$488
$488
$5,368
Annual
R & R costs
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$344,500
Annual Costs
$543,156
$534,944
$534,958
$26,988
$534,456
$789,613
$515,497
$534,944
$658,124
$534,944
$725,879
$480,163
$534,944
$6,948,610
oo
o
I
n>
a
o_
K'
€
63
8
o\
to
S:
5
CD
I
I
t
•S
o
1 Values in bold type indicate that an average value was used.
-------
Table 6-15. "Beyond the Floor" Cost Options for Exterior Siding, Doorskins and Miscellaneous3
2s rn c
Blind
facility
ID
E-l
E-2
E-3
E-4
E-5
E-6
E-7
E-8
E-9
E-10
E-ll
E-12
Totals
Synthetic
minor?
Yes
1
Small
business?
Yes
1
Number
of APCDs
\
0
1
1
1
1
3
1
1
0
1 •
1
12
TCI (RTO)
$1,886,475
$0
$1,886,475
$994,950
$1,886,475
$1,886,475
$7,753,137
$1,886,475
$1,197,984
$0
$1,372,781
$1,886,475
Annualizcd
TCI (RTO)
$460,094
$0
$460,094
$242,659
$460,094
$460,094
$1,890,918
$460,094
$292,177
$0
$334,809
$460,094
$5,521,127
Operating
costs (RTO)
$517,220
$0
$517,220
$251,614
$517,220
$517,220
$2,135,101
$517,220
$326,050
$0
$390,558
$517,220
$6,206,643
Performance
testing for
control
device(s)
$4,683
$0
$4,683
$4,683
$4,683
$4,683
$14,048
$4,683
$4,683
$0
$4,683
$4,683
$56,195
Computer
equipment costs
$0
. . $0
$0
$0
$0
$0
$0
$0
$0
$488
$0
$488
$976
Annual
R & R costs
$26,500
$0
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$26,500
$291,500
Annual costs
$1,008,497
$0
$1,008,497
$525,456
. $1,008,497
$1,008,497
$4,066,567
$1,008,497
$649,410
$26,988
$756,550
$1,008,985
$12,076,441
o
o
I
V
5'
I
I
v>
I
I
I
•s
I
ON
ON
'Values in bold type indicate that an average value was used.
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t
,8
U)
.O
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Table 6-16. "Beyond the Floor" Cost Effectiveness
MACT implementation
Doors and
windows
Model plants
Flooring
Interior
paneling and
tileboard
(Class 1
hardboard)
Other interior
panels
Exterior
siding,
doorskins, and
miscellaneous
Totals
Emission Reductions
Total organic HAP emission
reductions (ton/yr)
2,528
297
1,417
250
788
5,280
Total organic HAP emission
reductions (Mg/yr)
Costs
2,293
269
1,285
227
715
4,790
Performance Testing
$312,180
$187,308
$163,895
$108,062
$332,046
$1,103,491
Recordkeeping and Reporting
$1,325,000
$1,325,000
$397,500
$662,500
$1,722,500
$5,432,500
Computer Equipment
$16,259
$24,389
$1,219
$10,318
$5,765
$57,950
Annualized TCI (RTO)
$14,025,923
$3,814,765
$4,059,707
$6,013,838
$32,624,828
$60,539,061
Operating Costs (RTO)
$15,156,127
$3,849,750
$4,152,659
$6,567,977
$36,675,617
$66,402,130
Total annual cost for industry
$30,835,489
$9,201,212
$8,774,980
$13,362,695
$71,360,756
$133,535,132
Cost Effectiveness ($/ton)
$12,198
$30,981
$6,193
$53,451
$90,559
$25,291
Cost Effectiveness ($/Mg)
$13,445
$34,150
$6,826
$58,919
$99,824
$27,878.
1 Assumes 100% capture and 90% destruction.
6-27
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6.15 COMPARISON OF COST OPTIONS
For the wood building products (surface coating) NESHAP, there are two basic options of
organic HAP control. The use of low- or no-HAP coatings is valid as a pollution prevention
option and would cost the entire industry of 205 estimated major source facilities either $27.3
million. This option is considered a pollution prevention option since pollution that would
normally result from high-HAP coatings is avoided by the use of low- or no-HAP coatings. On
the other hand, the installation of RTOs is considered a pollution control option since these
devices destroy a fraction of the organic HAP emissions by oxidation.
The installation, operation, and maintenance of RTOs would cost the entire industry of 205 major
source facilities an estimated $133.5 million. This option is cost prohibitive, requiring six times
the amount of monetary investment and providing only 1.6 times the organic HAP reduction.
Therefore, the use of RTOs as a "beyond the floor" control option is not cost effective as a
compliance option for existing sources to meet the proposed NESHAP requirement.
6.16 REFERENCES
1. Memorandum from Reeves, D., MRI, to Lluberas, L., EPA/CCPG and Sorrels, L.,
EPA/ISEG. April 25, 1999. Number of Major Sources within the Wood Building
Products (Surface Coating) Industry.
6-28
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1. REPORT NO.
EPA-453/R-00-003
TECHNICAL REPORT DATA
(Please read Instructions on reverse before completing)
2.
4. TITLE AND SUBTITLE
National Emission Standards for Hazardous Air Pollutants
(NESHAP) for the Wood Building Products (Surface Coating)
Industry
7. AUTHOR(S)
Luis Lluberas
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Office of Air Quality Planning and Standards
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
12. SPONSORING AGENCY NAME AND ADDRESS
Office of Air and Radiation
U. S. Environmental Protection Agency
Washington, D.C. 20460
3. RECIPIENTS ACCESSION NO.
5. REPORT DATE
May 2001
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO
10. PROGRAM ELEMENT NO.
1 1. CONTRACT/GRANT NO.
68-D6-0012,TONo.47
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/OAR/OAQPS/ESD/CCPG
15. SUPPLEMENTARY NOTES
16. ABSTRACT*
Nation4l emission standards
Building Products (Surface Co
This standard will reduce emis
emit either 10 tons of one spec
as any finished or laminated w<
and is used in the construction,
These emission reductions are
coatings. This option is less cc
examined as an "beyond the flc
the HAP content, the solids coi
be used to calculate an overall
17.
a. DESCRIPTORS
to control the emission of hazardous aii
ating) industry are being proposed unde
sions from major source wood building
ific HAP or 25 tons of total HAP per ye
3od product that contains more than 50
either interior or exterior, of a resident!
expected through a switch from high-R
>st prohibitive than the use of a regenera
>or" control option. This regulation wil
itent and the amount of each coating ap
facility emission limit in units of Ib HA
r pollutants (HAP) fi
r Section 112 of the
product (surface co£
ar. A wood building
percent by weight w
al, commercial, or ii
AP coatings to low-
itive thermal oxidize
1 require each affecte
plied by the facility.
P/gal solids.
KEY WORDS AND DOCUMENT ANALYSIS
b. IDENTIFIERS/OPEN ENDED TERMS
surface coating, wood building products, air pollution, air pollution control
NESHAP, hazardous air pollutant, HAP, window, door, wood building product
panel, reconstituted wood, flooring, tileboard, doorskin, manufacturing
Class I hardboard, laminate flooring stationary sources
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (Report)
Unclassified
20. SECURITY CLASS (Page)
Unclassified
x>m the Wood
Clean Air Act.
iting) facilities that
I product is defined
ood or wood fiber
istitutional building.
orno-HAP
r (RTO), which was
;d source to track
These values will
c. COSATI Field/Group
21. NO. OF PAGES
22. PRICE
EPA Form 2220-1 (Rev. 4-77)
PREVIOUS EDITION IS OBSOLETE
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