EPA-600/R-98-016a
F ebruary 1998
DEMONSTRATION OF A PAINT SPRAY BOOTH
EMISSION CONTROL STRATEGY USING
RECIRCULATION/PARTITIONING AND
UV/OZONE POLLUTANT EMISSION CONTROL
Volume 1. Technical Report
EPA Contract No. 68-D4-0111
EPA Project Officer: Charles H. Darvin
Air Pollution Prevention and Control Division
National Risk Management Research Laboratory
Research Triangle Park, NC 27711
This Study Was Conducted in Cooperation with the United States Marine Corps:
Maintenance Directorate
Marine Corps Logistics Base
Albany, GA 31704
Marine Corps Multi-Commodity Maintenance Center
Barstow Marine Corps Logistics Base
Barstow, CA 92311
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, D.C. 20460
By
Jacqueline Ayer
Air Quality Specialists
2280 University Drive
Newport Beach, CA 92660
David Proffitt
Acurex Environmental Corporation
4915 Prospectus Drive, Suite F
Durham, NC 27713
Prepared for:
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completi | |||| || ||||
ii minimi
1. REPORT NO. 2.
EPA-600/R-98-016 a
3. i 1 111! II till
PB98-
ii i iiiiiiii 11
•124316
4. title and subtitle Demonstration of a Paint Spray Booth
Emission Control Strategy Using Recirculation/Par-
titioning and UV/Ozone Pollutant Emission Control,
Volume 1. Technical Report
5. REPORT DATE
February 1998
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Jacqueline Ayer (AQS) and David Proffitt (Acurex)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Air Quality Specialists A cur ex Environmental Corp.
2280 University Drive 4915 Prospectus Dr., Suite F
Newport Beach, CA Durham, NC
92660 27713
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-D4-0111
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Air Pollution Prevention and Control Division
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final; 9/93-6/97
14. SPONSORING AGENCY CODE
EPA/600/13
is.supplementarynotes^ppqj) project officer is Charles H. Darvin, Mail Drop 61, 919/
541-7633. Volume 2 contains Appendices A - E.
i6. abstract report describes in detail the source testing, construction, and data
reduction/analysis activities that comprise the three phases of a technology demon-
stration program. Phase I consisted of a detailed basline evaluation of several paint
spray booths operated at the Barstow (California) Marine Corps Logistics Base to
establish key operating parameters and air toxic emission profiles. This information
was used to design a safe recirculation/flow partitioning system for the paint booths
involved in the study to efficiently reduce the overall exhaust flow rate. Under Phase
II, the necessary booth construction and retrofit modifications were made, and the
air pollution control device was installed. The recirculation/flow partitioning sys-
tem was tested extensively as part of the Phase III effort to ensure that the booths
operated in accordance with health and safety standards mandated by the Occupa-
tional Safety and Health Administration (OSHA) and the National Fire Protection
Association (NFPA).
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. cosati Field/Group
Pollution
Spray Painting
Emission
Circulation
Ultraviolet Radiation
Ozone
Pollution Prevention
Stationary Sources
Booths
Recirculation
Flow. Partitioning
13 B
13 H
14G
20F
07B
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (This Report)
Unclassified
21. PAGES
121
20. SECURITY CLASS (This page)
Unclassified
22. PmCE
EPA Form 2220-1 (9-73)
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NOTICE
This document has been reviewed in accordance with
U.S. Environmental Protection Agency policyand
approved for publication. Mention of trade names
or commercial products does not constitute endorse
ment or recommendation for use.
Reproduced from
best available copy.
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FOREWORD
The U. S. Environmental Protection Agency is charged by Congress with pro-
tecting the Nation's land, air, and water resources. Under a mandate of national
environmental laws, the Agency strives to formulate and implement actions lead-
ing to a compatible balance between human activities and the ability of natural
systems to support and nurture life. To meet this mandate, EPA's research
program is providing data and technical support for solving environmental pro-
blems today and building a science knowledge base necessary to manage our eco-
logical resources wisely, understand how pollutants affect our health, and pre-
vent or reduce environmental risks in the future.
The National Risk Management Research Laboratory is the Agency's center for
investigation of technological and management approaches for reducing risks
from threats to human health and the environment. The focus of the Laboratory's
research program is on methods for the prevention and control of pollution to air,
land, water, and subsurface resources; protection of water quality in public water
systems; remediation of contaminated sites and groundwater; and prevention and
control of indoor air pollution. The goal of this research effort is to catalyze
development and implementation of innovative, cost-effective environmental
technologies; develop scientific and engineering information needed by EPA to
support regulatory and policy decisions; and provide technical support and infor-
mation transfer to ensure effective implementation of environmental regulations
and strategies.
This publication has been produced as part of the Laboratory's strategic long-
term research plan. It is published and made available by EPA's Office of Re-
search and Development to assist the user community and to link researchers
with their clients.
E. Timothy Oppelt, Director
National Risk Management Research Laboratory
iii
i
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PREFACE
This report was prepared for the U.S. Environmental Protection Agency (EPA) Air
Pollution Prevention and Control Division by Air Quality Specialists, 2280 University Drive,
Newport Beach, CA 92660. Air Quality Specialists developed this document under EPA
Contract 68-D4-0111 with Acurex Environmental Corporation, 555 Clyde Avenue, Mountain
View, CA, 94039.
This report describes in detail the source testing, construction, and data
reduction/analysis activities that comprise the three phases of the Technology Demonstration
Program. Phase I consisted of a detailed baseline evaluation of several paint spray booths
operated at the Barstow Marine Corps Logistics Base to establish key operating parameters and
air toxic emission profiles. This information was used to design a safe recirculation/flow
partitioning system for the paint booths involved in the study to efficiently reduce the overall
exhaust flow rate. Under Phase II, the necessary booth construction and retrofit modifications
were made, and the air pollution control device was installed. Extensive testing of the
recirculation/flow partitioning system was performed as part of the Phase III effort to ensure that
the booths operated in accordance with Health and Safety Standards mandated by the
Occupational Safety and Health Administration (OSHA) and the National Fire Protection
Association (NFPA).
Numerous agencies were involved in this Program, which was executed via cooperative
agreement between the U.S. Marine Corps Maintenance Directorate and the EPA's Air Pollution
Prevention and Control Division (APPCD).
iv
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CONTENTS
Preface iv
List of Figures viii
List of Tables iX
Unit Conversion Table xi
List of Abbreviations and Symbols xii
1 INTRODUCTION 1
1.1 Background 2
1.2 Program Objective 5
1.3 Overall Program Approach 6
1.3.1 Baseline Characterization Study 6
1.3.2 Booth Ventilation System and APCS Installation 7
1.3.3 Technology Demonstration Study 7
2 TECHNOLOGICAL INNOVATIONS OF THE PROGRAM 8
2.1 Recirculation/flow Partitioning Concept 8
2.1.1 General Recirculation/Flow Partition System Design Considerations ..10
2.1.2 Methodology for Calculating Partition Height 14
2.2 UV/Ozone Air Pollution Control System Innovations 17
2.3 Continuous, Speciated Organic Concentration Monitoring 20
3 SITE DESCRIPTION 23
3.1 Booth 1 General Description and Operating Characteristics 23
3.2 Booth 2 General Description and Operating Characteristics 25
3.3 Booth 3 General Description and Operating Characteristics 28
V
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4 BASELINE CHARACTERIZATION STUDY RESULTS 30
4.1 Baseline Study Results and Conclusions 30
4.1.1 Booth 1 Baseline Study Test Results and Assumptions Employed in
Partition Height Calculations 31
4.1.2 Booth 2 Baseline Study Test Results and Assumptions Employed in
Partition Height Calculations 34
4.1.3 Booth 3 Profile and Emission Rate Estimates Employed in Partition
Height Calculations 38
4.2 Baseline Study Design Recommendations and Conclusions 40
4.2.1 System Design Enhancements/Constraints Identified From
the Baseline Study 40
4.2.2 Baseline Study Conclusions and Projected Flow Reductions 41
4.2.3 General Comments on Recirculation with Respect to OSHA
Design Mandates 43
4.3 Results of Pre-retrofit Characterization Study 43
4.3.1 Flow Rate Variations 43
4.3.2 Particulate Concentration Profile 44
5 PAINT BOOTH MODIFICATION DESIGN ELEMENTS 46
5.1 Ventilation System Flow Rate Considerations 47
5.1.1 Advantages of Flow Control 47
5.1.2 Flow Control System Employed on MCLB Paint Booths 48
5.2 Safety Monitoring System 49
5.3 High Performance Particulate Filtration Requirements 50
5.4 Final Flow Rates 52
5.5 Paint Booth/APCS System Integration Requirements 53
6 TECHNOLOGY DEMONSTRATION STUDY RESULTS 56
6.1 Hazardous Constituent Concentrations Measured Upstream of Fresh
Makeup Air Intake in the Recirculation Ducts 56
6.1.1 Measurement Objective and Results 56
6.1.2 Implications of Recirculation Duct Sampling Results 61
6.2 Exhaust Face Constituent Concentration Profile Results 63
6.3 Hazardous Constituent Concentrations in the Vicinity of the Paint
Booth Operator 64
6.3.1 Measurement Objective and Results 64
6.3.2 Implications of Painter Vicinity Sampling Results 77
6.4 Comparison of FTIR Results to NIOSH 1300 Speciated Organic Data and FID
Results 79
vi
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7 ECONOMIC BENEFITS OF RECIRCULATION AND OTHER FLOW
REDUCTION STRATEGIES 85
7.1 Exhaust Flow Rates 85
7.2 VOC Emission Control Systems 86
7.3 Paint Booth Retrofit and Emission Control Cost Parameters 86
7.4 Cost Analysis Results 87
8 ENGINEERING CONCLUSIONS AND RECOMMENDATIONS 93
8.1 Program Conclusions 93
8.2 Program Recommendations 96
9 SUMMARY OF QUALITY ASSURANCE/QUALITY CONTROL RESULTS 97
9.1 Overall Data Quality and Critical Measurement Quality 97
9.2 Calculation of Data Quality Indicators 98
9.2.1 Accuracy 98
9.2.2 Precision 98
9.2.3 Completeness 99
9.2.4 Representativeness 99
9.3 Summary of Baseline Study QA/QC Results 100
9.4 Summary of Technology Demonstration Study QA/QC Results 100
9.5 EPA Field Audit Results 104
References 107
Appendices
A. Baseline and Technology Demonstration Study Sampling Procedures Vol.2
B. Baseline and Technology Demonstration Study Analytical Procedures Vol.2
C. Details of Baseline Characterization Study Results Vol.2
D. Details of Technology Demonstration Study Results Vol.2
E. Pre-Retrofit Characterization Test Report Vol.2
vii
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LIST OF FIGURES
Figure 1. Supplemental OSHA Documentation Pertaining to Recirculation (page 1) 3
Figure 2. Supplemental OSHA Documentation Pertaining to Recirculation (page 2) 4
Figure 3. Schematic Diagram of Simple Recirculation 9
Figure 4. Schematic Diagram of Recirculation/Flow Partitioning 9
Figure 5. Paint Booth Control Volume Configuration for Determining Partition Height 16
Figure 6. Schematic Diagram of the UV/Ozone APCS System 19
Figure 7. Schematic Diagram Indicating Locations and Relative Positions of the
Paint Booths and APCS Targeted by the Demonstration Program 24
Figure 8. Schematic Diagram of MCLB Booth 1 26
Figure 9. Schematic Diagram of MCLB Booth 2 27
Figure 10. Schematic Diagram of MCLB Booth 3 29
Figure 11. Estimated Booth 3 Constituent Concentration Profile 39
Figure 12. Cumulative Distribution of Metal and Organic Constituents at Various Heights
Across the Exhaust Face of Booth 1 68
Figure 13. Cumulative Distribution of Metal and Organic constituents at Various Heights
Across the Exhaust Face of Booth 2 69
Figure 14. Cumulative Distribution of Metal and Organic Constituents at Various Heights
Across the Exhaust Face of Booth 3 70
viii
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LIST OF TABLES
Table 1. Test Matrix for Baseline Study 32
Table 2. Baseline Study Average Concentration Profile and Painter Vicinity Test
Results for Booth 1 33
Table 3. Exhaust Duct Constituent Concentration and Flow Rate Data Obtained
from Booth 1 Baseline Study 34
Table 4. Baseline Study Average Concentration Profile Results for Booth 2 36
Table 5. Exhaust Duct Constituent Concentration and Flow Rate Data Obtained
from Booth 2 Baseline Study 37
Table 6. Constituent Concentrations in Booth 2 Painter Vicinity 38
Table 7. Summary of Partition Height Calculation Results and Corresponding
Flow Rate Reductions Projected from Baseline Study 42
Table 8. Exhaust Flow Rate Data Comparative Analysis Results 44
Table 9. Particulate Stratification Data Comparative Analysis Results 45
Table 10. Summary of Volume Flow Rate Reductions Achieved for MCLB Paint Booths ... 52
Table 11. Test Matrix for Demonstration Study 57
Table 12. Booth 1 Recirculation Duct Constituent Sampling Results 58
Table 13. Booth 2 Recirculation Duct Constituent Sampling Results 59
Table 14. Booth 3 Recirculation Duct Constituent Sampling Results 60
Table 15. Paint Usage Rates Recorded During Painter Vicinity OSHA Factor
Measurements 62
Table 16. Booth 1 Average Chrome Concentrations at Specific Exhaust Face Heights 66
Table 17. Booth 2 Average Chrome Concentrations at Specific Exhaust Face Heights 66
Table 18. Booth 3 Average Chrome Concentrations at Specific Exhaust Face Heights 66
Table 19. Booth 1 Average Organic Concentrations at Specific Exhaust Face Heights 67
Table 20. Booth 2 Average Organic Concentrations at Specific Exhaust Face Heights 67
Table 21. Booth 3 Average Organic Concentrations at Specific Exhaust Face Heights 67
Table 22. Booth 1 Painter Vicinity Measurements in Single-Pass Mode 71
Table 23. Booth 2 Painter Vicinity Measurements in Single-Pass Mode 72
Table 24. Booth 3 Painter Vicinity Measurements in Single-Pass Mode 73
Table 25. Booth 1 Painter Vicinity Measurements in Recirculation Mode 74
Table 26. Booth 2 Painter Vicinity Measurements in Recirculation Mode 75
Table 27. Booth 3 Painter Vicinity Measurements in Recirculation Mode 76
Table 28. Precision Analysis of Painter Vicinity OSHA Factor Measurements 78
Table 29. FTIR - NIOSH 1300 Comparison Summary for Booth 1 Recirculation
Duct Samples 80
Table 30. FTIR - NIOSH 1300 Comparison Summary for Booth 2 Recirculation
Duct Samples 81
ix
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List of Tables (Continued)
Table 31. FTIR - NIOSH 1300 Comparison Summaiy for Booth 3 Recirculation Duct
Samples 82
Table 32. TWA Levels Programmed into the FTIR OSHA Additive Rule Calculation 83
Table 33. Emission Control System Installation/Operating Costs at 1,176 m3/min 89
Table 34. Emission Control System Installation/Operating Costs at 3,285 m3/min 90
Table 35. Emission Control System Installation/Operating Costs at 4,064 m3/min 91
Table 36. Summary of Cost Analysis Results Comparing Emission Control Costs With and
Without Recirculation/Flow Partitioning 92
Table 37. Summary of Data Quality Achieved for the Phase I Baseline Study 101
Table 38. Summary of Data Quality Achieved for the Phase II Demonstration Study 102
Table 39. Summary of EPA Field Spike and Analysis Results 105
Table 40. Analytical Results of EPA Submitted Standards 106
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UNIT CONVERSION TABLE
English
SI
SI Symbol
To convert from English
to SI, Multiply by
Length
Inch
Foot
Centimeter
Meter
cm
m
2.54
0.3048
Area
Square inch
Square foot
Square centimeter
Square meter
cm2
m2
6.452
0.09290
Volume
Cubic inch
Cubic foot
Cubic centimeter
Cubic meter
cm3
m3
16.39
0.0283
Mass
Pound
Kilogram
kg
0.4536
Energy
Btu
Joule
Kilowatt-hour
J
kWh
1055
0.000293
Power
Horsepower
Btu/hr
Watt
Watt
W
W
745.7
0.2931
Tem
Derature
Fahrenheit
Celsius
°C
5/9 (°F - 32)
Flow Rate
Cubic feet/minute
Cubic meters/minute
m3/min
0.0283
Pressure
1 inch of H20
Pascal
Pa
249
Velocity
Ft/minute
Meter/second
Kilometers/hour
m/s
kph
0.005
0.0183
xi
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LIST OF ABBREVIATIONS AND SYMBOLS
ABBREVIATIONS
ACGIH - American Conference of Governmental Industrial Hygienists
APCS - Air pollution control system
APPCD - Air Pollution Prevention and Control Division
APV - Armored personnel vehicle
ARL - Applied Research Laboratory at Pennsylvania State University
Btu - British thermal unit
CARC - Chemical agent resistant coating
cfm - Cubic feet per minute
CFR - Code of Federal Regulations
DOD - U.S. Department of Defense
DQI - Data quality indicator
DQO - Data quality objective
EPA - U.S. Environmental Protection Agency
EUAC - Equivalent Uniform Annual Cash Flow
FID - Flame ionization detector
fpm - Feet per minute
FTIR - Fourier transform infrared detector
HDI - Hexamethylene diisocyanate
HVLP - High volume low pressure
IDLH - Immediately dangerous to life and health
LEL - Lower explosion limit
MACT - Maximum Achievable Control Technology
MCLB - Marine Corps Logistics Base, Barstow
MC3 - Marine Corps Multi-Commodity Maintenance Center
MEK - Methyl ethyl ketone
MIAK - Methyl isoamyl ketone
MIBK - Methyl isobutyl ketone
MSDS - Material Safety Data Sheet
NFPA - National Fire Protection Association
NIOSH - National Institute of Occupational Safety and Health
OSHA - Occupational Safety and Health Administration
PEL - Permissible Exposure Level
PGMEA - Propylene glycol monoethyl ether acetate
xii
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PID
- Photoionization detector
PPE
- Personal protective equipment
ppm
- Parts per million
QA
- Quality assurance
QAO
- Quality Assurance Officer
QAPjP
- Quality Assurance Project Plan
QC
- Quality control
RPD
- Relative percent difference
SERDP
- Strategic Environmental Research and Development Program
STEL
- Short term exposure limit
TLV
- Threshold limit value
TWA
- Time weighted average
USMC
- United Stated Marine Corps
UV
- Ultraviolet
WD
- Variable frequency drive
VOC
- Volatile Organic Compound
SYMBOLS
C
- Concentration
f3
- Cubic feet
Hz
- Hertz
kg
- Kilograms
mA
- Milliamp
mg
- Milligram
m3
- Cubic meters
Q
- Flow rate
w.c.
- water column
SUBSCRIPTS
; - Constituent i
r - Recirculation stream
m - Fresh make-up air stream
b - Booth
e - Exhaust stream
- As carbon
xiii
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SECTION 1
INTRODUCTION
Developing energy efficient and cost-effective strategies for controlling emissions of
volatile organic compounds (VOCs) and hazardous air pollutants from paint application
processes is a key objective of the U.S. Environmental Protection Agency (EPA) and the
Department of Defense (DoD). Both the EPA and the DoD have sponsored extensive research
and development programs that focus on new approaches and innovative solutions to reduce the
economic and operational impacts of controlling low concentration VOC emission sources.
In the Fall of 1993, the EPA's Air Pollution Prevention and Control Division (APPCD)
joined with the U.S. Marine Corps (USMC) under the Strategic Environmental Research and
Development Program (SERDP) to launch a comprehensive technology demonstration program
that combined several innovative strategies for cost effectively controlling VOC emissions from
USMC paint spray booths. The Marine Corps Logistics Base in Barstow, CA (MCLB) was
selected as the host site for the EPA/USMC Technology Demonstration Program; MCLB is a
high production facility that generally operates year round at two-three shifts per day. These
operating conditions provide an ideal situation for conclusively demonstrating the viability and
applicability of the various technological innovations that were considered in the EPA/USMC
Demonstration Program. Moreover, unlike most programs of this type, MCLB intends to
maintain the hardware and system modifications that were installed for the EPA/USMC
Demonstration Program. This will provide program participants with the opportunity to conduct
a realistic, long-term performance evaluation of these innovative strategies.
The EPA/USMC Technology Demonstration Program consisted of two major system
design and installation efforts which were carefully coordinated and integrated to ensure
efficient system operation. The first effort entailed comprehensive ventilation system
modifications to several of the paint spray booths operated at MCLB. The objective of these
modifications was to significantly reduce the exhaust volume flow rate from these sources,
thereby reducing the installation and operating costs associated with add-on emission controls.
The second effort focussed on the installation and optimization of an innovative air pollution
control system that relies on ultraviolet light and ozone to eliminate the VOCs present in the
paint booth exhaust stream. The results of the paint booth modification/evaluation efforts and
the UV/Ozone emission control system installation/optimization activities completed under the
EPA/USMC Technology Demonstration Program are documented in this final report. This
program, which concluded in the Fall of 1996, was conducted under the auspices of the U.S.
EPA and the U.S. Marine Corp from funding made available by the EPA and the DoD.
1
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1.1 BACKGROUND
In 1987, the EPA and the U.S. Air Force jointly initiated a comprehensive technology
evaluation and demonstration program with the objective of identifying and evaluating cost-
effective VOC emission control strategies for paint spray booth applications. The results of the
first phase of that program, which focused on candidate process modifications for reducing
emission control costs, indicated that the most straightforward and effective approach was
simply to reduce the exhaust flow rate emitted from the paint application processes.1 Reducing
the exhaust volume flow rate allows a corresponding reduction in the size, capacity, installation
cost, and operating requirements of the emission control device. For example, the capital and
installation cost of a 2,832 m3/min (100,000 ft3/min) rotor concentrator catalytic oxidizer air
pollution control system (APCS) is approximately $1,800,000 (1995 dollars). By reducing the
exhaust flow rate to 1,216 m3/min (50,000 cfm), the APCS installation cost is reduced to
approximately $1,000,000 (1995 dollars). Annual operating costs are similarly reduced from
$49,000 to $27,000 (equipment cost data supplied by Diirr Industries, Inc. of Plymouth, MI).
The significant economic advantages of flow reduction were readily apparent, thus the
EPA/Air Force program targeted various flow reduction strategies for further investigation; these
studies focussed on realistic limits that could be placed on the strategies which were considered.
These limits relate to the health and safety aspects of ventilation system design, and are
regulated by the Occupational Safety and Health Administration (OSHA) and the National Fire
Protection Association (NFPA). Key safety issues that were addressed during the Air Force/
EPA program are discussed briefly in this section; additional details are provided in Section 2.
Recirculation was the first flow reduction strategy considered under the joint EPA/Air
Force program. Recirculation involves venting only a portion of the booth exhaust to an APCS;
the remainder of the exhaust is recirculated back into the booth after mixing with fresh make-up
air. Unfortunately, in 1987 when the EPA first recommended the use of recirculation it was
believed by the USAF to be prohibited by both OSHA and NFPA. Eventually research results
from field studies developed by EPA convinced OSHA and Air Force officials that these
prohibitions stemmed from concerns relating to fire and explosion hazards and not worker health
considerations. After an extensive coordination and review by the EPA, OSHA, and USAF,
OSHA revised their policy specifically stating that recirculation could be implemented if (and
only if) the recirculation system adequately ensured compliance with applicable OSHA rules
pertaining to worker health. A copy of this supplemental OSHA document is shown in Figure 1.
NFPA had revised their standard relating to recirculation in 1985. That revision can be found in
the 1985 edition of NFPA 33, section 5.5.2.2
Throughout this recirculation review period, EPA and Air Force continued to jointly
develop and evaluate potential improvements to the basic recirculation technology. These
efforts culminated in the development of an enhanced flow reduction strategy known as
recirculation with flow partitioning; addition of the flow partitioning enhancement enables a
further increase in the recirculation rate, and correspondingly an additional decrease in the
2
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U^> Department of Labor Oca^eor^ s«*ny »od H»m Adrr»rt»traBcn
WMbioston. D.C. 20210
R*pfy to tS« Aatrien at
AN 15 CO
Susan JL Wyatt, Chi*f
Chssicilr ~nd Petrols!** 5r*n?-h
Emission Standard* Division
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
D«?r Hs. Vyatt:
This is in response to your letter of October 31, 1989,
concerning the Occupational Safety and Health Administration
(OSHA) regulation at 29 C73. 1910.107(d)(9) which prohibits the
recirculation of-exhaust air from spray finishing operations.
Please excuse the delay in response.
you are avare, 2S CTR 1910.107 was adopted froa the KFPA 33-
:n69, Standard for Spray Finishing Using Flammable and Combust-
ible Materials. The KFPA-33 .standard is explicitly a fire and
explosion safety standard. Therefore,' the OSEA standard at 29-
CFR 1510.1C7 pertains to the prevention of voricplace fire and
explosion hazards and does not pertain to health considerations.
Although the KFPA has updated their standard since the 1563
edition, OSHA has not. As a result, the current NFPA 33-1985,
Spray Application Using Flammable and Combustible Materials,
reflects the most up to data state of the art concerning.the
prevention of firs and -Explosion hazards during spray finishing
operations.
Under an CSKA policy for "de minimis violations", employers are
encouraged to abide by the most current consensus standard
applicable to their operations, rather than vith the standard in
affect at the tire of the inspection vhen the employer's action
provides equal or greater employee protection. De minimis
violations are violations of existing OSHA standards vhich have
no direct oj .ia=«£iai« rslsticnship to ccfoty cr health: such
violations of the OSEA standards result in citation, no
penalty and no required abatement. A copy oi the CSHA policy for
ds minimis violations is enclosed.
Figure 1. Supplemental OSHA Documentation Pertaining to Recirculation (page 1).
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Zaployers vho fully coaply with th« specifications and require-
ments of the H7PA 33-1989, eoncerainq the recirculation cf
exhaust air to an occupied #pray booth, vould not be cited under
29 CTR 1910*107 (5} (9} under the policy for d« minimis violations.
However, the quality of the respirable air in the booth aust
coaply, at a ainisun, vith the requirements set forth by 29 cm
1910.1000 which establishes permissible exposure liaits (PEL's).
If ve aay be of xurfcasr sssistsncs, plssss =s3it*et us.
Figure 2. Supplemental OSHA Documentation Pertaining to Recirculation (page 2).
/
4
Reproduced from
best available copy.
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exhaust flow rate.3
The Recirculation/Flow Partition technology was successfully demonstrated in a small
paint booth at Travis Air Force Base (AFB) in 1992.4 However, the Travis AFB demonstration
did not include integration of the booth ventilation system with an add-on APCS; rather the
exhaust was discharged to atmosphere. Additional information relating to the recirculation and
recirculation/flow partitioning technologies are provided in Section 2.
Based on the successful results of the EPA/Air Force program, the USMC elected to
implement a full-scale technology demonstration project that combined the recirculation/flow
partitioning strategy with an innovative air pollution control strategy that relies on ultraviolet
(UV) light and ozone to successfully remove VOCs and organic air toxic compounds from
process exhaust streams. For the EPA/USMC Technology Demonstration Program described
herein, three paint spray booths at MCLB were modified to accommodate recirculation/flow-
partitioning. The exhaust streams from these booths were integrated and directed to the
UV/Ozone APCS.
The EPA/USMC Technology Demonstration Program combines several new, "cutting
edge" technologies; the innovative aspects of this program; therefore, necessitated careful
consideration of safety and logistical issues during the system design and installation phase. For
example, the correct recirculation rate for each booth was derived based on detailed and
comprehensive baseline test data to ensure that the booths would always operate in compliance
with OSHA health and safety requirements. To maintain compliance with these health and
safety regulations, a VOC monitoring system that provides real-time, speciated organic
concentration data was developed and installed to continuously monitor constituent
concentrations in the recirculation ducts. Furthermore, to minimize the impact of paint
overspray on the UV/Ozone control system and reduce overspray material in the recirculation
stream, an evaluation of paint booth filtration systems was performed to select an advanced
overspray collection media.
This report summarizes these innovative aspects of the Demonstration Program, and
discusses in detail the comprehensive testing, engineering evaluation, design, construction, and
system validation activities that were undertaken to ensure safe and efficient paint booth
operations. The results of the APCS technology demonstration study are presented in a separate
USMC/ARL report.
1.2 PROGRAM OBJECTIVE
The primary objectives of the EPA/USMC Technology Demonstration Program were: 1)
to demonstrate that recirculation/flow partitioning ventilation provides a safe and cost-effective
means of controlling pollutant emissions from military paint spray booths; and 2) to develop and
install APCS system enhancements to further increase the effectiveness of the UV/Ozone
system. The research activities undertaken to develop the UV/Ozone APCS system
5
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enhancements were conducted at the Pennsylvania State University Applied Research
Laboratory (ARL). As part of the SERDP effort, the ARL system enhancements could then be
implemented on the full scale UV/Ozone APCS installed at MCLB.
1.3 OVERALL PROGRAM APPROACH
The EPA/USMC Technology Demonstration Program was initiated in the Fall of 1993,
and was implemented in three separate phases:
Phase I - Baseline evaluation of existing Barstow paint spray booth operations
Phase II - The design and installation of the recirculation/flow partition system.
This Phase also included a complete booth characterization study
performed immediately prior to any construction modifications to
confirm that booth operations did not change significantly after the
baseline study.
Phase III - The demonstration and testing of the recirculation/flow partition
system.
The approach that was adopted to successfully complete these phases is summarized below.
1.3.1 Baseline Characterization Study
The objective of the Baseline Characterization Study was to develop a safe and efficient
recirculation/flow partitioning system for each of the three paint booths targeted by this
Demonstration Program. The Baseline Characterization Study comprised three steps:
1) Collect site-specific process operating information and correlate these results with
facility data to establish the appropriate recirculation rate for each booth. This
involved extensive source testing, and sample analysis activities, which are
summarized in Section 4.
2) Reconcile the source test results with facility process data that were collected during
the Step 1 sampling efforts, and project a safe and efficient recirculation rate and
partition height for each of the paint spray booths. This step required a significant
level of data reduction, correlation, and evaluation. Background data relating to the
recirculation calculations that were performed and the key health and safety issues
that were addressed are provided in Section 2.
3) Develop conceptual designs for the recirculation/flow partitioning ventilation
systems to be installed on each of the paint spray booths. This step addressed
important site-specific issues such as exhaust filter system requirements for
6
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protecting the downstream APCS, fan system and make-up air intake configurations,
flow control and safety system monitors, etc. Several key issues that were addressed
during Step 3 of the Baseline Characterization Phase are discussed in Section 5. Two
primary system constraints that relate to booth design were also addressed during this
Phase. These constraints (discussed in detail in Section 2) include:
- The concentration of hazardous constituents in the recirculation stream
(which dictates the level of recirculation that is achievable); and
- The 100 fpm volume flow rate level required by OSHA (which dictates
the size and capacity of the ventilation equipment and the APCS).
1.3.2 Booth Ventilation System and APCS Installation
Phase II of the EPA/USMC Technology Demonstration Program consisted of two
separate design and construct efforts which were completed in parallel. One of the
design/construction efforts focussed on retrofitting the paint booth ventilation system and
exterior structures to accommodate recirculation/flow partitioning. Information relating to some
of the key ventilation system considerations and design decisions are summarized briefly in
Section 5. The MCLB paint booths were then modified during the Phase II effort in accordance
with the structural and ventilation system retrofit requirements specified in the final design
drawings. This effort also included a complete booth characterization study performed
immediately prior to any construction modifications to confirm that booth operations did not
change significantly after the baseline study.
A second design/construction effort was undertaken to install the UV/Ozone air pollution
control system. The system was designed, installed and tested under the direction of USMC
program staff. The paint booth modification team coordinated their design/construct efforts
with the UV/Ozone APCS installation team to ensure efficient system integration.
1.3.3 Technology Demonstration Study
The goal of the third and final phase of this Demonstration Program was to characterize
in detail the performance of the recirculation/flow partition systems installed on each of the
paint spray booths. The performance characterization activities included assessing the health
and safety aspects of the recirculation system (discussed in Section 5), establishing the viability
of an innovative safety monitoring system (discussed in Section 2), and evaluating the overall
performance of the booth operations after the retrofit activities were completed.
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SECTION 2
TECHNOLOGICAL INNOVATIONS OF THE PROGRAM
The EPA/USMC Technology Demonstration Program encompasses several technological
innovations; indeed the primary objective of this program was to demonstrate the viability of
these technologies at a full scale production facility. Although the technologies discussed in this
section are truly innovative and; therefore, are not in widespread use, Barstow MCLB considers
these retrofit modifications to be permanent installations, and as such, will rely on their
continual and successful operation well into the next century. This was a key consideration in
the overall design and installation approach employed for retrofitting the paint booths. This
section focuses on the various technological innovations included in this demonstration program.
2.1 RECIRCULATION/FLOW PARTITIONING CONCEPT
There are numerous advantages to recirculation ventilation, including energy efficiency,
cost effective ventilation system operation, and a significant reduction in air pollution control
system capital, installation, and operating costs. The energy efficiency and cost effectiveness of
recirculation is a function of the recirculation rate; thus maximizing recirculation will also
maximize system efficiency and cost savings. However, as indicated in Section 1, the volume of
air that may be recirculated is limited by various safety requirements relating to permissible
exposure levels and minimum booth ventilation rates, as specified by OSHA. Therefore, a safe
and efficient recirculation system will maximize the recirculation rate, yet ensure compliance
with applicable OSHA requirements.
A common recirculation ventilation strategy, known as simple recirculation, is illustrated
schematically in Figure 3. In simple recirculation, a portion of the booth exhaust is removed
through a bleed-off duct and vented to an emission control device. The remainder of the exhaust
passes back into the booth via a recirculation duct connected to the exhaust plenum. Prior to re-
entering the paint booth, the recirculated air is mixed with fresh make-up air which is introduced
to replace the bleed-off air. As discussed in detail below, the OSHA regulations which govern
recirculation system operations specify that the hazardous constituent concentrations in the
recirculation stream must not exceed safe levels. In simple recirculation, the hazardous
constituent concentrations in the recirculated stream are the same as in the bleed-off stream, thus
the flow reduction achievable by simple recirculation is limited by the bulk exhaust stream
concentration. Therefore, it follows that recirculation may be safely enhanced by configuring
the ventilation system such that the hazardous constituent concentrations in the bleed-off stream
are higher than in the recirculation stream. This enhancement is achieved via recirculation/flow
partitioning, which is illustrated schematically in Figure 4.
8
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Fresh
Make-up / / /
A|R v/>/ Bypass Duct
\
Filter Face'
J
\ Exhaust Air
Vented to APCS
Figure 3. Schematic diagram of simple recirculation.
Fresh
Make-up
Air
Filter Face"
J
Bypass Duct
Partition
Exhaust Air
Vented to APCS
Figure 4. Schematic diagram of recirculation/flow partitioning.
9
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The recirculation/flow partitioning system takes advantage of constituent stratification
that occurs naturally in a laminar, cross-flow paint booth. The recirculation/flow partitioning
strategy specifically relies on the fact that solid and vapor phase constituents tend to remain at or
below the level at which they are released in the paint booth. This system withdraws air from
the booth zone that has the highest paint overspray particulate and solvent vapor concentrations,
and directs this contaminated air to an air pollution control system. Correspondingly,
recirculated air is drawn from the zone within the booth that has the lowest constituent
concentrations. The recirculation/flow partitioning strategy; therefore, safely enhances the
recirculation rate and cost effectiveness of paint booth ventilation system operation beyond the
level that is achieved by simple recirculation.
As indicated in Section 1, the recirculation/flow partitioning technology was developed
under a joint EPA/Air Force recirculation technology study at Hill AFB.3 Significant constituent
stratification was found to occur in the paint booths that were tested; based on these findings, the
concept of selectively recirculating from relatively low concentration zones in the booth was
developed.
2.1.1 General Recirculation/FIow Partition System Design Considerations
Numerous system design and implementation issues must be addressed in developing a
safe and efficient recirculation/flow partition system. The key safety requirements that must be
considered are contained in federal health and safety regulations codified in the NFPA Standards
and the Code of Federal Regulations (CFR). Other design issues that should be considered
include fan system requirements for ensuring consistent booth ventilation flow rates, safety
monitoring, and constituent concentration profiles at the exhaust face (necessary for calculating
the partition height). These issues are discussed separately below.
Safety Regulations Codified in NFPA 33: The NFPA 33 standard is primarily motivated by
concerns relating to fire and explosion hazards.2 As such, the overriding section of the standard
that impacts recirculation limits the airborne concentration of flammable compounds to less than
25% of the compound lower explosion limit (LEL). However, the LELs for solvents typically
present in paint booth operations are much higher than the allowable worker exposure levels
mandated by OSHA (discussed in detail below). Therefore, by complying with the OSHA
exposure limit requirements, the NFPA standards are automatically met. For example, the
allowable 8-hour worker exposure limit for xylene is 100 ppm, the LEL for xylene is 10,000
ppm, thus 25% of the LEL is 2,500 ppm. Therefore, if the recirculation system is properly
designed to comply with OSHA requirements (i.e. the organic constituent concentrations remain
well below the 100 ppm exposure limit), the recirculation system will, by default, comply with
the 2,500 ppm LEL limit specified in the NFPA 33 standards.
Applicable Health and Safety Requirements Mandated in the CFR: The safety requirements that
impact the recirculation/partition flow design are codified in 29 CFR 1910.94 (which governs
minimum required ventilation flow rates that must be maintained in occupied paint spray
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enclosures), 29 CFR 1910.107 (which specifies exhaust system configuration requirements), and
29 CFR 1910.1000 (which governs worker exposure to hazardous constituent concentrations).5'6,7
29 CFR 1910.94 requires that, for spray enclosures in which non-electrostatic paint
application equipment is used (such as the HVLP systems employed at Barstow MCLB), a
minimum linear velocity of 100 feet per minute (fpm) must be maintained through the booth.5
To ensure that this safety requirement is met for any and all equipment configurations that are
encountered in the Barstow MCLB paint booths, the booth ventilation systems were designed to
maintain a minimum 100 fpm linear velocity irrespective of the size or configuration of the
workpiece that is coated. In addition, 29 CFR 1910.94 refers to NFPA Standard 33 and specifies
that the solvent vapor concentrations remain below acceptable explosion limits; as indicated
above, this requirement is met if the system is properly designed to conform with allowable
worker exposure limits specified by OSHA.
29 CFR 1910.107 pertains to spray finishing operations in which flammable and
combustible materials are employed.6 In fact, subpart (d)(9) specifically states "Air exhaust
from spray operations shall not be directed so that it will contaminate makeup air being
introduced into the spraying area...". It further states "Air exhausted from spray systems shall
not be recirculated". However, as indicated by OSHA in their interpretive letter (Figure 1), the
objective of the 29 CFR 1910.107 prohibition is similar to that of the 29 CFR 1910.94
regulation; namely, it is intended to minimize fire and explosion hazards and is not related to
worker health issues. The Figure 1 text continues to state that, if the recirculation system is
designed to ensure compliance with worker exposure limits (codified in 29 CFR 1910.1000 and
discussed in detail below), then the prohibition indicated in subpart (d)(9) is not applicable.
The purpose of 29 CFR 1910.1000 is to prevent worker exposure to excessive levels of
hazardous airborne constituents; as such, OSHA has mandated that the hazardous constituent
concentrations contained in the respirable air must remain below established safety limits.7
Because the recirculation rate impacts the quality of respirable air in the booth (along with other
factors such as airflow patterns in the booth, target configuration, etc.), it must be calculated
based on these safety limits.
OSHA has defined three exposure limits below which the respirable air constituent
concentrations must be maintained:
1) 8-hour time weighted average (TWA) constituent concentrations known as
Permissible Exposure Limits (PELs).
2) 15-minute time weighted average (TWA) constituent concentrations known as Short
Term Exposure Limits (STELs).
3) Ceiling limits referred to as Immediately Dangerous to Life and Health (IDLH).
Under no circumstances are hazardous concentrations to exceed IDLH values.
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The PEL is defined as the concentration at which no adverse health effects are expected
for most workers exposed to the contaminant for eight hours per day, 5 days per week.
Generally speaking, the PEL is the lowest exposure limit of those identified above, and therefore
yields the most conservative safety limit.
In addition to OSHA, the National Institute of Occupational Safety and Health (NIOSH)
and the American Conference of Governmental Industrial Hygienists (ACGIH) have established
their own TWA levels for various time intervals that may also be used as guidelines for
controlling worker exposure levels. Similar to the OSHA PEL values, the ACGIH Threshold
Limit Values (TLVs) and the NIOSH Recommended Exposure Levels (RELs) are typically based
on 10-hour time weighted average limits. Both NIOSH and ACGIH have also established short
term limits and ceiling limits.
The NIOSH and ACGIH exposure limits are guidelines, and are not enforced by OSHA.
However, there are numerous compounds for which NIOSH and/or ACGIH have established
TWA limits, but OSHA has not; for example, OSHA has established only a ceiling limit of 0.1
mg/m3 for hexavalent chromium (Cr+6) as Cr03, and does not currently have an 8 hour PEL for
this compound. Conversely, NIOSH has proposed a 10 hour TWA value of 0.001 mg/m3 as Cr 6
(rather than as Cr03), which is considerably lower than the OSHA ceiling level. For the purpose
of establishing safe and efficient recirculation rates under the EPA/USMC Technology
Demonstration Program, the Cr+610 hour TWA limit recommended by NIOSH was employed,
as indicated in Appendix D. For chemicals with no established PEL or TLV, an exposure limit
was either determined through review of published literature, or based on manufacturer's
recommendations. These maximum exposure airborne chemical concentration limits (PELs,
TLVs, or other limits) are referred to as TWAs throughout the remainder of this document.
For mixtures of hazardous constituents which are present in the respirable air, OSHA
mandates that the additive effect of each constituent be considered in determining worker
exposure limits. The OSHA additive rule for determining the bulk TWA for mixtures specifies
that the sum of hazardous constituent concentrations divided by their respective TWAs must not
exceed unity:
" [concentration].
TWA' ~
(1)
Where:
[concentration];
TWA;
Concentration of specific hazardous constituent
TWA of specific hazardous constituent
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This equation, typically, is applied only to compound groups that have additive medical
effects. However, to ensure more conservative results for the EPA/MCLB Technology
Demonstration Program, all hazardous constituents were grouped together, and a single additive
rule calculation was performed. Moreover, USMC staff elected to apply an additional safety
factor of two in addition to the safety factor inherent in the PPE worn by the booth operators.
Thus, the actual OSHA additive equation (subsequently referred to as OSHA Factor) employed
to derive the partition height and associated recirculation rate for the EPA/USMC Technology
Demonstration Program was:
" Hconcentration1. A [
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added level of worker safety. In the event that the monitor detects unacceptably high
concentrations in the recirculation duct, the safety system should, at a minimum, activate a
damper system that vents the recirculated air to atmosphere. This allows the booth to be flushed
with 100 percent fresh make-up air, thereby returning the booth to a safe operating environment.
Details relating to the MCLB paint booth safety monitors are provided in Section 2.3.
Other parameters that are critical for designing a safe and efficient recirculation/flow
partition system include:
1) The hazardous constituent concentration profile at the exhaust face; this provides key
stratification information necessaiy to determine the appropriate partition height.
Extensive paint booth exhaust face testing was performed during the Baseline
Characterization Study (Section 4) to derive the profile data required for determining
the partition height.
2) The collection efficiency of the exhaust filter system; this is particularly critical for
operations that rely on paints which contain inorganic hazardous constituents such as
hexavalent chromium or phosphoric acid. For the Barstow MCLB Demonstration
Program, three-stage high efficiency filters were installed in each of the paint booths
to maximize particulate collection and, correspondingly, hexavalent chromium
removal. The partition height calculations (discussed in Section 4) performed for
each of the Barstow MCLB booths assumed a 99% filtration efficiency for hexavalent
and total chrome.
3) Booth volumetric flow rate; this is dictated by the 100 fpm minimum velocity
requirements established by OSHA and the booth cross sectional area.
2.1.2 Methodology for Calculating Partition Height
The first step in calculating the appropriate partition height is to derive a mathematical
expression for the hazardous constituent concentrations occurring in the recirculation duct as a
function of partition height. It is also necessary to define system limits with respect to the
applicable safety standards. For example, USMC Staff provided guidance mandating that the
partition height be selected to ensure that the limit established by Equation 2 apply to the
recirculation air upstream of where it is mixed with fresh make-up air. By constraining the
quality of the recirculated air as it exits the booth to the 0.5 OSHA Factor limit, a significant
safety margin is included in the calculation, because no dilution factor benefit is considered in
the final design.
The mathematical expression for determining a safe partition height is developed via a
simple mass balance evaluation using standard control volume analysis techniques. The result
of this analysis for non-steady state conditions yields an exponential expression in which time
appears as an independent variable in the exponent. However, a more conservative result is
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obtained by assuming a steady state booth operation in which maximum (worst case) conditions
prevail. Under steady state conditions, the mass balance equation at the booth intake face
(Location A in Figure 5) reduces to:
(QrxCr)HQmxCm)= (Qbxcb) (3)
Where:
Qr = Volume Flow Rate of Recirculated Air
Cr = Hazardous Constituent Concentrations in Recirculated Air
Qm = Volume Flow Rate of Fresh Makeup Air
Cm = Hazardous Constituent Concentrations in Fresh Makeup Air
Qb = Volume Flow Rate Through Paint Booth
Cb = Hazardous Constituent Concentrations in Air Upstream of Painter Location
The first two terms in Equation 3 represent the constituent mass flow rates in the
recirculation stream and the make-up air stream, respectively. The third term; therefore, defines
the constituent mass flow rate at the booth intake face. If it is assumed that the makeup air is
free of hazardous constituents, the mass balance equation at the intake face (Location A, Figure
5) simplifies to:
(QrxCr)= (Qbxcb)
(4)
Similarly, under steady state conditions, the mass balance equation at the booth exhaust face
(Location B, Figure 5) reduces to:
(Qb*cb) +
Mg=(Q,
r-cr) + (Qexce)
(5)
Where:
Qe = Volume Flow Rate of Exhaust Air Vented to the APCS
Ce = Hazardous Constituent Concentrations in Exhaust Air Vented to the APCS
Mg = Hazardous Constituent Mass Generation Rate from Paint Application Process
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Recirculation Flow Qr, Cr
>
Qb, Cb
Mg
Qm, Cm
>
Make-up Air
Exhaust Air
A
B
Figure 5. Paint booth control volume configuration for determining partition height.
The left side of Equation 5 represents the mass flow rate at the booth intake face and the
hazardous constituent mass generated by the spraying operation occurring within the booth. The
right side of Equation 5 defines the mass flow rate exiting the booth into the recirculation duct
(Qr x Cr) and into the exhaust duct vented to the APCS (Qe x Ce). The constituent concentration
profile at the booth exhaust face generated by the spray operation is not uniform, thus an
additional relationship must be derived and incorporated into Equation 5 that relates the
concentration profile at the exhaust face (Location B in Figure 5) to the constituent mass flow
rate in the recirculation and exhaust streams. This relationship reduces Equation 5 to:
a = Partition Height
H = Exhaust Face Height
X = Percent of Hazardous Constituents Generation in Booth Exiting above Height a
(QrxCr)= (QbxCb)(l- |)+ (Mxl)
(6)
Where:
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The second term in Equation 6 represents the hazardous constituent mass flow rate that is
introduced at the intake face (Location A in Figure 5) which passes to the recirculation duct.
The third term is the hazardous constituent mass flow rate contributed by the painting operation
that passes to the recirculation duct. The mathematical expression defining the relationship
between the constituent concentrations in the recirculation stream and the partition height (or
recirculation rate) is derived by combining the booth intake face mass balance relationship
(Equation 4), with the booth exhaust mass balance expression (Equation 6):
C„ =
MgxX
(7)
Q x ( —)
The partition height and corresponding recirculation rate that yields acceptably low
hazardous constituent concentrations in the booth intake stream may be derived iteratively from
Equation 7. However, straightforward application of Equation 7 may not be necessarily
appropriate, because filtration efficiency must be factored in for the solid or semi solid-phase
constituents (e.g. isocyanate or hexavalent chromium containing aerosols). Moreover, the
parameter X differs for the vapor phase and non vapor phase hazardous constituents due to
particulate drop-out, flow patterns, etc. As such, it is apparent that the partition height and
corresponding recirculation rate necessary to maintain safe intake concentrations depend on
several booth operating parameters. The objective of the Phase I Baseline Study (discussed in
detail in Section 4) was to accurately establish these operating parameters, which in turn were
used to project safe and cost-effective recirculation system estimates.
2.2 UV/OZONE AIR POLLUTION CONTROL SYSTEM INNOVATIONS
A second innovation integrated into the EPA/USMC Technology Demonstration Program
was the installation and operation of an efficient and cost-effective APCS that relies on
ultraviolet light (UV) and ozone to successfully oxidize organic compounds present in the
exhaust stream vented from the MCLB paint spray booths. The advantages of UV/Ozone
systems over traditional thermal oxidation systems include:
High Energy Efficiency - The UV/Ozone system operates at ambient temperature, which
eliminates the significant energy losses typically incurred by traditional APCS units that
rely on high temperature oxidation. These traditional units must bring the control stream
to elevated temperatures to ensure complete oxidation of the VOCs that are present.
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Minimal Start-up Time - Because the UV/Ozone system operates at ambient temperature,
it can switch from shut-down mode to fully operational in a matter of minutes. This is a
significant advantage over traditional APCS systems, which often require continuous
operation (such as in stand-by mode under minimal turn-down conditions), or significant
start-up time to bring the unit to temperature prior to bringing the process on-line.
No Secondary Pollutants - The emission of secondary pollutants such as NOx and CO
(generated at elevated combustion temperatures) is virtually eliminated due to the low
temperature operation of the UV/Ozone system.
Long Equipment Life - equipment integrity is maintained on a long term basis due to
ambient temperature operation.
Low Cost Operation - The electricity cost of operating the UV lamps is much lower than
the cost of supplying natural gas to traditional thermal systems.
The UV/Ozone technology involves a five step process to achieve adequate destruction
efficiency. This process, illustrated schematically in Figure 6, comprises:
1) Direct Photolysis - Downstream of a particulate filter, the process exhaust stream is
exposed to direct UV light to initiate oxidation.
2) Scrubber - The exhaust passes through a water scrubbing system where the miscible
and water soluble compounds are transferred into the aqueous phase.
3) Adsorbing Media Module - Exhaust passes from the scrubber to an adsorbing media
module which collects the remaining organics. The exhaust then vents to atmosphere.
4) Scrubber Water Clean-up - The scrubber liquid exiting the scrubber is treated with
ozone to completely oxidize the collected organics; the liquid is then recycled back
into the scrubber.
5) In-Situ Oxidation of Adsorbing Media - The organic compounds collected in the
adsorbing module are oxidized via ozone which is introduced into the module during
the media regeneration cycle.
The decision made by MCLB to install and operate a UV/Ozone system was motivated
primarily by the numerous inherent advantages offered by this technology, as indicated above.
Several UV/Ozone systems have been installed to control emissions from aerospace painting and
depainting facilities, as well as other industrial coating process sources. The largest UV/Ozone
system that has demonstrated long term operation is a 200,000 cfm system installed in 1992 in
Arizona. The particular innovations encompassed by the MCLB UV/Ozone system were based
on elements from the following:
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Wet
Scrubber
Ozone/
Water
Contact
Unit
_ Booth Exhaust Air
-¦ Scrubber Liquid
Ozone Injection
Carbon
Adsorption
Module
Particulate
Filter
Ozone
Generator
Figure 6. Schematic diagram of the UV/Ozone APCS system.
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1) A detailed system research and development effort that was planned, managed and
executed by the Applied Research Laboratory (ARL) at Pennsylvania State University
(Penn State). The objective of this research was to identify process and system
enhancements that may be implemented in full scale systems to further improve the
destruction capabilities of the photolytic reactor (Step 1 of the UV/Ozone oxidation
process).
2) A second research and development study, also performed by ARL, in which
mechanisms were studied for improving the speed and efficiency of in-situ oxidation
occurring in the adsorbing media module during the regeneration cycle.
3) Appropriate retrofit modifications and system adjustments to transfer the process and
system enhancements developed by ARL into the full-scale MCLB UV/Ozone
system.
The results of the ARL studies are summarized in a separate document that is published
by the U.S. Marine Corps. To date, no modifications have been made to the MCLB UV/Ozone
system to incorporate the system enhancements developed under the ARL research program.
Therefore, the results of innovative UV/Ozone system enhancement activities undertaken at
MCLB could not be included in this final report.
2.3 CONTINUOUS, SPECIATED ORGANIC CONCENTRATION MONITORING
A third innovation pioneered under the EPA/USMC Technology Demonstration Program
is the development and installation of a fully automated continuous organic monitor which
provides real-time, speciated organic concentration data. The monitor, which relies on Fourier
Transform Infrared (FTIR) analysis, is employed as the safety monitoring device to continuously
monitor hazardous constituent concentrations in the paint recirculation ducts. Continuous
analyzers that have traditionally been used in this and other VOC monitoring applications rely
on an ionization reaction to produce a signal which is proportional to the concentration of
organic carbon present in the sample stream. The most common monitors of this type include
flame ionization detectors (FIDs) and photoionization detectors (PLDs). It has long been
recognized by industrial facilities and regulatory agencies alike that ionization detectors in
general, and FIDs in particular, have significant drawbacks that limit their applicability and
impact their performance and cost effectiveness. These limitations include:
Non-Specificity - The measured results are reported in units of parts per million of
carbon (ppmc) or propane, thus speciated organic concentration data is not provided.
This is of particular concern when monitoring process streams in which the relative
concentrations of various organic components vary significantly over time (such as in
paint booth operations). For example, a 480 ppmc measurement made by an FID could
indicate the presence of either 120 ppm of methyl ethyl ketone (MEK), 80 ppm of
methyl isobutyl ketone (MIBK), or 120 ppm of 2-butanol. Non-specificity problems are
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compounded in the recirculation duct monitoring application, because the OSHA PELs
for these compounds differ significantly; the OSHA PELs for MEK, MEBK, and 2-
butanol are 200 ppm, 100 ppm, and 100 ppm, respectively. Thus, in this example, it is
not possible to determine if recirculation stream concentrations exceed the PEL (2-
butanol), are approaching the PEL, (MIBK) or are well below the PEL (MEK).
Response factor variability - Ionization detectors do not respond linearly as a function of
the number of organic carbon molecules present in the sample stream. A linear response
implies that there is a one-to-one correspondence between the ppmc value reported by the
instrument and the actual number or organic carbon atoms that are present. For example,
sample streams containing 100 ppm of xylene and MEK should correspond to FED
measurements of 800 ppmc and 400 ppm c, respectively. However, the FID may actually
indicate only 700 ppm and 380 ppmc due to the non-linear characteristic of the
instrument response. Note that the non linearity (referred to as response factor) varies as
a function of compound. Thus a drop in ppmc level measured by an FID could indicate a
change in sample stream constituents, or a change in concentration, or both.
Excessive calibration andfuel gas requirements - It is necessary to frequently calibrate
FIDs and PIDs to ensure accurate and reliable data. Furthermore, FIDs require a source
of hydrogen gas as a fuel supply for the ionizing flame. While these calibration and fuel
gas requirements are not impossible to meet, they tend to increase instrument operating
and maintenance costs in continuous monitoring applications.
In an effort to maximize operational flexibility and data accuracy, and minimize system
maintenance and operating requirements, the EPA, in concert with MCLB, elected to evaluate
alternatives to ionization detectors for use in the recirculation safety monitoring system. The
FTIR technology was selected for several reasons, including:
Real-Time, Speciated Organic Concentration Results - The FTIR provides
concentration results for the organic hazardous constituents of concern that are
present in the recirculation stream on a real time basis. Data are collected and
analyzed in sampling intervals of less than 30 seconds.
Real-Time OSHA Compliance Assessment Capabilities - Because the FTIR provides
real-time constituent concentration results, it is possible to determine the OSHA
compliance status of the recirculation stream on a continuous basis. This is
accomplished by programming the instrument control software to derive the additive
OSHA Factor (Equation 2) for each measurement event.
Significantly Reduced Calibration Gas and Instrument Maintenance Requirements -
The instrument requires neither fuel gas nor calibration gases to operate effectively.
However, because this is a new application for this technology, and because of the
importance of the safety monitoring system, it was decided to program the instrument
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control software to collect a reference spectrum with an appropriate check gas twice
a day. This will provide a means of assessing instrument stability on a long term
basis. This check may be discontinued after a period yet to be determined.
Despite the clear advantages of FTIR over other candidate monitoring systems, it was
recognized that a continuously operated, fully automated FTIR system had never before been
attempted in any application similar to that required by the recirculation safety system. It was;
therefore, necessary to perform a detailed evaluation to assess the effectiveness and overall
applicability of FTIR in this operation.
As part of this evaluation, a side-by-side comparison between traditional organic
sampling methods and FTIR measurement procedures was conducted. This comparison, which
involved collecting FTIR data simultaneously with integrated air toxic samples and continuous
FID data, was performed during the source test activities undertaken as part of the Phase III
Demonstration Study. The results of this analysis are summarized in Section 6. It is anticipated
that the successful demonstration of FTIR in such a difficult and demanding application will
provide a basis for further expanding the general acceptability of this versatile and highly useful
technology.
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SECTION 3
SITE DESCRIPTION
The U.S. Marine Corps Multi-Commodity Maintenance Center (MC3) near Barstow,
California provides extensive vehicle and ground equipment maintenance support services to the
Marine Corps as well as other DOD operations. The facility provides a covered work space that
spans 10 acres and houses 1,066 employees skilled in 78 different trades. There are 500 product
lines operated within the enclosure, which rebuilds and refinishes up to 250 vehicles per month.
MC3 encompasses numerous industrial process operations, such as metal finishing, plating,
equipment cleaning and repair, etc; many of which generate emissions of criteria and air toxic
pollutants. In particular, the surface priming and painting operations at MC3 are sources of
significant VOC emissions, which made these sources prime candidate sites for the EPA/USMC
Technology Demonstration Program.
This section describes the general location and configuration of three paint booths that
were modified for this Demonstration Program, and provides booth-specific information that
was employed during the Baseline and Technology Demonstration Studies, and while
developing the retrofit modification packages. The paint booth modification efforts and the
APCS design/ installation efforts were undertaken by separate contractors. However, the paint
booth and APCS installation efforts were coordinated sufficiently to ensure the booth ventilation
system operation and controls were adequately integrated with the APCS operation.
The sites targeted by the Demonstration Program are three paint booths located in the
Northwestern sector of Building 573, in the Yermo Annex of Barstow MCLB. A schematic
diagram indicating the locations and relative positions of the three paint booths and the
UV/Ozone APCS is provided in Figure 8. Most of the coatings used in these booths are in the
Marine Corps CARC (Chemical Agent Resistant Coatings) system, which includes wash
primers, epoxy primers, and polyurethane topcoats.
3.1 BOOTH 1 GENERAL DESCRIPTION AND OPERATING CHARACTERISTICS
Booth 1 is a large vehicle drive-through paint booth that is primarily used for applying
polyurethane topcoat to 2.5 and 5 ton armored personnel vehicles (APVs), Humvees, and other
Marine Corps vehicles. Occasionally other types of equipment are painted in Booth 1 as well,
such as helicopters and containers. The Booth 1 operating profile differs significantly from the
profiles for Booths 2 and 3 in that it is used exclusively for topcoat applications; wash primer
and epoxy primer are never used in Booth 1. This is significant, because the hazardous
constituent concentrations in the polyurethane topcoat consist primarily of organic compounds,
23
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UV/OZONE SYSTEM
O / 0
NJ
PAINTBOOTHS
2 & 3.
PAINTBOOTH 1
I"
~L *
D
TO
td
I.
rrri
:r.
"ID
Ji
nil
IIZL
VfWWtll MMl M 'tn
Figure 7.
Schematic Diagram Indicating Location and Relative Position of the Paint Booths and APCS Targeted by the
Demonstration Program.
-------
thus the solvent constituent concentrations in the topcoat material tend to dominate the
recirculation/flow partition calculation (Equations 2 and 7).
A schematic diagram of Booth 1 indicating the general arrangement of the recirculation
and exhaust ducts is provided in Figure 8. The booth is approximately 5.5 meters (18 feet) high,
6.1 meters (20 feet) wide, and 18.2 meters (60 feet) deep. It is equipped with a cross draft
ventilation system in which intake air is introduced into the front of the booth via an intake
plenum. As the ventilation air passes through the booth, it picks up overspray particulate and
solvent vapors. It then exits the booth and either passes to the APCS (if taken from below the
partition), or is recirculated back into the booth (if taken from above the partition).
3.2 BOOTH 2 GENERAL DESCRIPTION AND OPERATING CHARACTERISTICS
Booth 2 is a cross draft facility equipped with an overhead conveyor system. The
conveyor, which is used to transport equipment components and other items into the booth,
facilitates painting by suspending the workpieces so that they are accessed easily and uniformly
coated. Equipment that is painted in Booth 2 include small vehicle components such as wheel
assemblies, battery cases, vehicle suspension components, etc. Although numerous coatings
may be applied in Booth 2, the CARC system consisting of wash primer, epoxy primer,
polyurethane topcoat and thinners is primarily used (> 87%). A component of the CARC wash
primer is strontium chromate, which contains chromium in the hexavalent form. The OSHA
PEL for hexavalent chromium is quite low. In fact, wash primer material usage proved to be the
critical parameter in determining the Booth 2 partition height (which determines the
recirculation rate).
Although only one painter is typically stationed in Booth 2 during normal operations, all
tests conducted throughout the Demonstration Program on Booth 2 involved two painters.
Therefore, the Booth 2 tests were conducted at high usage conditions to reflect worst case
operations and therefore ensure conservative results and safe operation of the recirculation
system. The results of the Phase III Technology Demonstration Study presented in Section 6
indicate an adequate safety margin to ensure that two painters can safely operate in Booth 2 if
necessary.
A schematic diagram of Booth 2 indicating the general arrangement of the recirculation
and exhaust ducts is shown in Figure 9. The booth is approximately 3.0 meters (10 feet) high,
9.1 meters (30 feet) wide, and 6.1 meters (20 feet) deep. It is equipped with a cross draft
ventilation system in which intake air is introduced through the ceiling at the front of the booth;
fresh make-up air which is taken from the area surrounding the booth is also drawn through the
ceiling via a perforated plate. As the ventilation air passes through the booth, it picks up
overspray particulate and solvent vapors. It then exits the booth and is either passed to the
APCS (if taken from below the partition), or is recirculated back into the front of the booth (if
taken from above the partition).
25
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Exhaust Ducts
... Vented to APCS
Recirculation Ducts
Flow Partitions
Direction of Air Flow
Fresh Make-up Air
Intake Through
Perforated Plate
Intake Plenum
Figure 8. Schematic Diagram of MCLB Booth 1.
26
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Recirculation Ducrt
Flow Partition
Exhaust Duct
Vented to APCS
Exhaust Duct
Inlets
..Direction of Air Flow
Fresh Make-up
Air Plenum
Fresh Make-up i
Intake Through
Perforated Plate
Figure 9. Schematic Diagram of MCLB Booth 2.
27
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Booth 2 was originally constructed with an open face configuration, thus the painter
typically operated outside the minimal enclosure that the open face booth provided. As is
typical for open face paint booths, the volume flow rate exhausted from Booth 2 prior to
modification was quite high to ensure that adequate ventilation is provided in the vicinity of the
painter. By enclosing the work area as part of the retrofit modifications, the volume flow rate
through Booth 2 was significantly reduced. A second advantage of enclosing Booth 2 is that the
fugitive emissions previously released from the open face are now collected, and a capture
efficiency of 100 percent is achieved.
3.3 BOOTH 3 GENERAL DESCRIPTION AND OPERATING CHARACTERISTICS
Booth 3 is a cross draft enclosure that houses a parts coating operation and which was
moved from another area in Building 573. Booth 3 may be equipped with a pallet transportation
system; large equipment components that are placed on a pallet may be transported into and
through the booth on rollers. Although numerous coating materials may be applied in Booth 3, it
is anticipated that the CARC system consisting of wash primer, epoxy primer, polyurethane
topcoat and thinners will be used primarily. As with Booth 2, the presence of hexavalent
chrome in the CARC wash primer tends to drive the Booth 3 partition height calculation.
Although Booth 3 is typically used on an intermittent basis, the recirculation duct tests
conducted in Booth 3 during the Demonstration Study were performed at very high usage rates
to simulate worst case conditions (see Section 6).
A schematic diagram of Booth 3 that indicates the general arrangement of the
recirculation and exhaust ducts is provided in Figure 10. The booth is approximately 3.0 meters
(10 feet) high, 6.7 meters (22 feet) wide, and 3.0 meters (10 feet) deep. It is equipped with a
cross draft ventilation system in which intake air is introduced through a wall of filters via an
intake plenum. Fresh make-up air which is taken from the area surrounding the booth is drawn
into the intake plenum via a perforated plate, where it is mixed with the recirculated air. As the
ventilation air passes through the booth, it picks up overspray particulate and solvent vapors. It
then exits the booth and either passes to the APCS (if taken from below the partition), or is
recirculated back into the front of the booth (if taken from above the partition).
28
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Recirculation Ducts
Flow Partition
'Exhaust Duct
Vented to APCS
Direction of Air Flow
-up Air
Intake Througn
Perforated Plate
Fresh Make-i
Intake Plenum
Figure 10. Schematic diagram of MCLB Booth 3.
29
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SECTION 4
BASELINE CHARACTERIZATION STUDY RESULTS
An extensive baseline evaluation of the MCLB paint spray booths was performed in the
Fall of 1993 to collect relevant process operating and emissions data used to properly design the
recirculation/'partition flow system, and to develop a pre-moaification data set for subsequent
comparison to data collected after modifications are completed. The results of this Baseline
Study are summarized in Section 4.1. A summary of the recirculation calculations derived from
the Baseline Study data and a general discussion regarding the overall flow rate reductions
projected for each booth is provided in Section 4.2.
To ascertain whether or not Booth 1 operating characteristics had changed during the two
year interval between the Baseline Study (Fall, 1993) and the booth modification activities, (Fall,
1995) a second Booth 1 characterization test was performed in the Fall of 1995 immediately
prior to initiating booth modification activities. The results of the Pre-retrofit Characterization
are summarized briefly in Section 4.3.
4.1 BASELINE STUDY RESULTS AND CONCLUSIONS
The Baseline Study was performed in the Fall of 1993; the objective of this study was to
gather sufficient MCLB paint booth process operating data to project a reasonable and safe
partitioned recirculation system. As indicated in Section 2, the parameters necessary to derive
the partition height and the resulting recirculation rate include:
• Solid and vapor phase hazardous constituent concentration profiles at the exhaust
face
• Particulate collection efficiency of the exhaust filter
• Vapor phase hazardous constituent release rates from the paint gun
• Paint booth volumetric flow rates
The Baseline Study characterized each of these parameters for Booths 1 and 2. As
discussed in Section 2, Booth 3 design parameters were developed from engineering estimates
because Booth 3 involved new construction. In Booths 1 and 2, hazardous constituent
concentration measurements were also collected in the vicinity of the paint booth operator
outside of the supplied-air respirator (personal protection equipment [PPE]). The objective of
the painter vicinity tests was to obtain general air quality data in the areas in which the painter
operates and assess the performance of the existing ventilation system in providing adequately
safe working conditions.
30
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The test matrix developed and implemented for the Baseline Study is summarized in
Table 1. The Baseline Study results are briefly summarized in Sections 4.1.1 and 4.1.3.
Detailed information relating to the sampling and analysis methods are summarized in
Appendices A and B, respectively. Tabulated results of these sampling and analysis efforts are
provided in Appendix C.
4.1.1 Booth 1 Baseline Study Test Results and Assumptions Employed in Partition Height
Calculations
The constituent concentration profile results and painter vicinity data obtained from the
Booth 1 source testing activities are summarized in Table 2. These concentration profile results
were derived from exhaust filter face measurements and were used to define the parameter "X"
in Equation 7. The exhaust duct flow rate and concentration measurement results used to define
the Booth 1 recirculation rates are summarized in Table 3. From these results, the following
assumptions were made to derive the input data for the Booth 1 recirculation/flow partition
calculations (defined by Equation 7):
1) The maximum organic concentrations measured in the Booth 1 exhaust ducts were
used for the organic mass release rate parameter.
2) The maximum zinc and total chromium measurement results were used for the
inorganic compound concentrations; all chromium was assumed to be in the trivalent
form.
3) The worst case results (highest detection limit) for hexamethylene diisocyanate (HDI)
measured in the Booth 1 exhaust ducts were used for the HDI release rate parameter.
4) A volume flow rate of 962 m3/min (34,000 cfm) is required in Booth 1 to maintain
compliance with the 100 fpm minimum velocity requirement mandated by OSHA.
However, the Baseline Study data indicate that Booth 1 exceeded this minimum flow
rate by a significant margin (Table 3). It was therefore concluded that variable
frequency drive (VFD) fans could safely reduce Booth 1 flow rates while maintaining
compliance with the minimum ventilation requirements mandated by OSHA.
The initial Booth 1 recirculation/flow partition calculation results indicated that the
optimal partition height was 2.68 meters (8.8 feet). However, during the detailed design phase
(discussed in Section 5), it was decided that the Booth 1 ventilation system would operate more
efficiently if an extra row of filters was added to the Booth 1 exhaust face. The optimal partition
height yielding and OSHA Factor of 0.65 was then re-calculated at 2.65 meters (8.7 feet).
31
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Table 1. Test Matrix for Baseline Study.
Objective
Location
Parameter
Sampling Method
Booth 1
Determine stratification
Exhaust faces
Metals
Isocyanates
Speciated organics
Particulate
Flow rate
NIOSH 7300s
OSHA 429
NIOSH 1300'°
NIOSH 50011
Anemometer
Determine exhaust
concentrations
Exhaust ducts
Metals
Isocyanates
Speciated organics
Total organics
Particulate
Flow rate
EPA Method 006012
NIOSH 552113
NIOSH 130010
EPA Method 25A14
NIOSH 500"
Anemometer
Establish OSHA Factor
in the vicinity of the
paint booth operators
Vicinity of paint
booth operators
Metals
Isocyanates
Speciated organics
Particulate
NIOSH 73008
NIOSH 552113
NIOSH 130010
NIOSH 50011
Compare collection
efficiency of existing
filtration system to the
Exhaust face with
standard filters
Particulate at face
Particulate in ducts
Flow rate
NIOSH 50011
EPA Method 515
EPA Method 216
high performance
filtration system.
Exhaust face with
high performance
filters
Particulate at face
Particulate in ducts
Flow rate
NIOSH 500n
EPA Method 515
EPA Method 2,s
Booth 2
Determine stratification
Exhaust faces
Metals
Speciated organics
Particulate
Flow rate
NIOSH 7300s
NIOSH 130010
NIOSH 50011
Anemometer
Determine exhaust
concentrations
Exhaust ducts
Metals
Speciated organics
Total organics
Flow rate
NIOSH 7300s
NIOSH 130010
EPA Method 25A14
Anemometer
Establish OSHA Factor
in the vicinity of the
paint booth operators
Vicinity of paint
booth operators
Metals
Speciated organics
Particulate
NIOSH 7300s
NIOSH 130010
NIOSH 50011
The Baseline Study QAPjP refers to this method as the EPA Draft Method 29 Multi-Metals Sampling
Procedure. In the time interval since the Baseline Study was completed, EPA finalized the draft method and
now refers to it as Method 0060. The name change is reflected in this Table.
32
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Table 2. Baseline Study Average Concentration Profile and Painter Vicinity Test Results for Booth 1
(unless indicated, all units are mg/m3).
Height
m (feet)
MEK
Ethyl-
benzene
Xylene
s
n-Butyl
acetate
MIAK
Toluene
n-Butyl
alcohol1
Hexyl
acetate
PGMEA1
Total
Chrome2
Zinc
HDI
3.9(12.8)
2.2
0.7
3.0
2.6
28
0.9
0.06
0.3
0.2
0.007
0.12
0.0008
2.9 (9.5)
6.2
3.2
13
11
120
2.5
0.08
2.0
0.7
0.022
0.29
0.0020
2.4 (7.8)
7.7
3.9
17
14
170
3.2
0.07
2.8
1.3
0.031
0.46
0.0039
1.85 (6.1)
8.7
4.8
20
17
190
3.6
0.07
2.9
1.2
0.049
0.71
0.0050
1.4 (4.5)
10.2
5.9
25
21
270
4.3
0.16
4.1
1.1
0.052
0.82
0.0062
0.33(1.1)
7.6
4.2
19
16
200
3.2
0.07
3.2
1.0 «
0.032
0.50
0.0039
Painter
Vicinity3
(avg)
16.9
10.2
47
39
400
8.2
0.11
6.2
1.1
0.0087
0.013
0.0040
These compounds were measured at or below the method detection limit, thus to ensure conservative results in the recirculation/flow partition
calculations, the detection level concentration was assumed.
As indicated in Section 2, Booth 1 is used only for topcoat applications, and therefore only trivalent chromium is present in Booth 1.
These results are averaged over all the Booth 1 painter vicinity test data collected. These results correspond to an average OSHA Factor of 1.3, with
OSHA Factor range of 1.0 to 1.6.
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Table 3. Exhaust Duct Constituent Concentration and Flow Rate Data Obtained from
Booth 1 Baseline Study.
Parameter
North Duct Concentrations
(mg/m3)
South Duct Concentrations
(mg/m3)
MEK
4.0
5.2
Ethylbenzene
3.3
3.0
Xylenes
17
9.6
n-Butyl acetate
13
7.7
MIAK
95
110
Toluene
2.1
2.6
n-Butyl alcohol1
0.09
0.04
Hexyl acetate
2.2
3.3
PGMEA
1.3
0.74
Total Chromium
0.00
0.00056
Zinc
0.037
0.063
HDI1
7.14
7.14
Flow Rate m3/min (cfm)
1,367 - 1,625 (48,266 - 57,394)2
1 The concentrations measured were essentially at the method detection limit, thus this limit was employed
in the recirculation/flow partition calculation.
2 The Booth 1 exhaust flow rate tended to decrease throughout the test as a result of the exhaust filters
gradually loading up with paint overspray particulate. To maintain compliance with OSHA requirements
mandated in 29 CFR 1910, the minimum Booth 1 volume flow rate required is 963 m3/min (34,000
cfin), thus these flow rates significantly exceed the levels mandated by OSHA.
4.1.2 Booth 2 Baseline Study Test Results and Assumptions Employed in Partition
Height Calculations
The constituent concentration profile results and painter vicinity data obtained from
the Booth 2 source testing activities are summarized in Table 4. These concentration profile
face results were derived from exhaust filter face measurements and were used to define the
parameter "X" in Equation 7. The exhaust duct flow rate and concentration measurement
results that were used to define the Booth 2 recirculation rates are summarized in Table 5. As
discussed in Section 2, the configuration of the Booth 2 exhaust system did not lend itself to
accurate flow rate or isokinetic sampling, thus the flow rate data reported in Table 5 were
34
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derived from anemometer measurements taken at the exhaust face. Similarly, the metal
concentration values assumed in the Booth 2 recirculation/flow partition calculations were
derived from the exhaust face chromium concentration profile. From these results, the
following assumptions were made to derive the input data for the Booth 2 recirculation/flow
partition calculations:
1) The maximum organic concentrations measured in the Booth 2 exhaust ducts were
used for the organic mass release rate parameter.
2) Based on the Booth 2 measurement results and observations made during the
painting activities, it was determined that substantially more than half of the total
chromium released in Booth 2 exists in the less toxic trivalent form. To derive
more conservative results for the Booth 2 recirculation/flow partition calculation,
it was therefore assumed that one half of the Booth 2 total chromium is in the
hexavalent state, and one half is in the trivalent state.
3) A 99-percent filtration efficiency (by weight) was assumed for the advanced
filtration system.
4) The ratio of zinc to hexavalent chromium concentration in Booth 2 is equal to the
ratio measured in Booth 1 during the single wash primer test. This is a reasonable
assumption, because zinc is present only in the wash primer; it is not a topcoat
component.
5) The HDI to MIAK mass ratio measured for Booth 1 was employed to estimate the
Booth 2 exhaust duct HDI concentrations for the recirculation/flow partition
calculation.
The results reported in Tables 4 and 5 were coupled with engineering estimates and
operating data to derive the input data for the Booth 2 recirculation/flow partition
calculations. Moreover, only one painter typically operates in Booth 2, yet two painters were
operating in Booth 2 during the exhaust face and exhaust duct sampling activities. Taking
into consideration all of these issues, the optimal Booth 2 partition height yielding an OSHA
Factor of 0.5 was calculated at 2.04 meters (6.7 feet). Moreover, because this partition height
was determined assuming that 2 painters operate in the booth, it ensures extremely
conservative operation of the recirculation system, and a safe operating environment for the
worker.
Booth 2 was originally constructed in an open face configuration such that the paint
booth operators were positioned outside of the enclosure during paint application. To ensure
adequate ventilation air around the painter operating outside the booth, the volume flow
through an open face booth is typically much higher than is required for an enclosed booth. It
was recognized that one of the major benefits of modifying and enclosing Booth 2
35
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Table 4. Baseline Study Average Concentration Profile Results for Booth 2 (unless indicated, all units are mg/m3).
Height
m
(feet)
MEK
Ethyl
Benzen
e
Xylen
es
n-Butyl
Acetat
e
MIA
K
Toluen
e
n-Butyl
Alcoh
ol
Hexy
1
Acet
ate
PGM
EA
Chrome1
2.7 (9.0)
2.1
0.21
0.57
0.54
4.6
2.4
5.4
0.15
0.03
0.039
2.1 (7.0)
5.6
0.64
2.5
0.28
18
4.4
6.7
1.7
0.21
1.7 (5.7)
11
1.6
6.2
7.2
44
12
21
4.0
0.6
0.12
1.3 (4.3)
18
2.8
11
12
76
18
28
7.5
1.2
0.22
0.9 (3.0)
18
2.6 „
9.7
11
76
18
28
8.5
1.1
0.17
0.3(1.0)
352
1.8
8.2
14
35
22
26
12
0.09
The chromium measurements were taken during the second test series conducted under the Baseline Study (see Section 2). These measurements
were taken at the following heights: 8.75 ft., 6.25 ft., 3.75 ft., and 1.25 ft.
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Table 5. Exhaust Duct Constituent Concentration and Flow Rate Data Obtained from Booth
2 Baseline Study.
Parameter
North Duct
(mg/m3)
South Duct
(mg/m3)
MEK
3.0
8.5
Ethyl benzene
0.19
1.7
Xylenes
0.89
6.3
n-Butyl acetate
0.54
5.8
MIAK
6.3
59
Toluene
6.2
3.1
n-Butyl alcohol1
7.2
0.08
Hexyl acetate
2.3
1.6
PGMEA1
0.04
0.04
Flow Rate2 m3/min (cfm)
1,435 - 1,922 (50,700 - 67,900)
1 The concentrations measured were essentially at the method detection limit, thus this
limit was employed in the recirculation/flow partition calculation.
2 The Booth 2 exhaust ducts were not adequately configured to enable accurate flow rate measurements
or isokinetic sampling. The flow rate values reported here were derived
from anemometer data collected at the exhaust face. Note also that the Booth 2 flow
rates tended to decrease throughout the Baseline Study as a result of the exhaust filters
gradually loading up with paint overspray particulate.
for recirculation was that the overall flow rate through the booth would be significantly
reduced; this is because the minimum flow rate required by OSHA after enclosing Booth 2 is
906 m3/min (32,000 cfm) as opposed to the 1,678 m3/min (59,300 cfin) average determined
for Booth 2 in the open face configuration (see Table 5).
It was further hypothesized that the overall Booth 2 ventilation characteristics and
quality of the air in the painter vicinity would improve, because the painter would operate in a
fully ventilated area (e.g. the air flow rate in the vicinity of the painter would be a consistent
100 fpm). As such, the ventilation air in the reconfigured booth would be more effective at
moving contaminants away from the paint booth operator. To test this hypothesis, some
constituent concentration samples in the vicinity of the Booth 2 painters were collected during
the Baseline Study. The results of these measurement activities are provided in Table 6,
37
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which summarizes three sets of total chromium measurement results and two sets of sets of
organic concentration data. As discussed in detail in Section 6, the Table 6 results were
compared with similar test data collected during the Technology Demonstration Study; the
results of this comparison clearly indicate that the quality of ventilation air in the painter
vicinity was significantly improved by enclosing Booth 2 and improving the ventilation
system.
Table 6. Constituent Concentrations in Booth 2 Painter Vicinity.
Constituent
Test 1
Test 2
Test 3
Average
Metals
Total
0.084
0.106
0.0241
0.095
Chromium
Organics
MEK
6.6
4.2
5.4
Ethylbenzene
0.76
0.04
0.4
Total Xylenes
2.9
0.22
0.026
Butyl acetate
3.8
0.16
1.9
MIAK
19
1 'I
1.Z,
10
Toluene
2.5
3.3
2.9
n-Butyl alcohol
<0.06
3.9
1.9
1 Hie Test 3 measurement was taken in the vicinity of the painter applying the primer, which contains
hexavalent chromium. The Test 1 and 2 samples were collected in the vicinity of the painter applying
topcoat, which contains trivalent chromium. Note that the chromium concentration in the vicinity of the
painter applying primer is significantly lower than the concentrations in the vicinity of the painter
applying topcoat, these results indicate that tri valent chromium comprises the bulk of the total chromium
present in Booth 2.
4.1.3 Booth 3 Profile and Emission Rate Estimates Employed in Partition Height
Calculations
It was not possible to perform a detailed evaluation of Booth 3 because the booth was not
fully functional at the time of the Baseline Study. Thus engineering estimates of the exhaust
face constituent concentration profiles and exhaust duct constituent concentrations were
developed to derive appropriate input data for the recirculation/'fiow partition calculations.
These estimates were developed from booth configuration considerations, process operating
information, and the source test results obtained for Booths 1 and 2. The following
information was employed to develop the estimated profile illustrated in Figure 12 and
establish appropriate partition height calculation input data:
1) The total Booth 3 coating usage was projected to be one eighth to one quarter of
Booth 2 usage.
38
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0 1 1 I | 1 1 1 0 9'
2 2 2 3 3 3 2 2 2 7'
4 6 8 —10 10 10 0 6 4 5'
2 3 4 6 6 6 4 3 2 3'
2 3 4 6. 6 6 , 4 3 2 1'
1 ¦ :
Figure 11. Estimated Booth 3 Constituent Concentration Profile (note, except for those indicating height in feet, numbers indicated
are non-dimensional and should be considered in terms of relative concentration levels).
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2) A maximum of 25 pallets of equipment may be coated per day.
3) Three pallets could be placed in Booth 3 per paint event. Wash primer, epoxy primer,
and topcoat will be applied to all three pallets sequentially.
4) No more than one paint gun may operate in Booth 3 at any given time.
5) The estimated Booth 3 constituent emission rates are one-half the levels determined
for Booth 2. This is extremely conservative, particularly because only one painter
operates in Booth 3 at a time. Furthermore, MCLB projects that the Booth 3 daily
coating usage will be much lower than the Booth 2 daily coating usage; therefore it is
anticipated that Booth 3 instantaneous coating usage rates will be lower as well.
Based on these parameters, the optimal Booth 3 partition height yielding an OSHA Factor of
0.5 was calculated at 2.04 meters (6.7 feet).
4.2 BASELINE STUDY DESIGN RECOMMENDATIONS AND CONCLUSIONS
The data collected from Baseline Study were reduced and used as inputs to the mathematical
model developed in accordance with the equations presented in Section 2 to derive a safe and
efficient partition height and recirculation rate. The results of this mathematical analysis
indicated that the exhaust volume flow rate from the MCLB paint booths could be safely
reduced by a significant margin. Baseline Study results also proved very useful in developing
the recirculation/flow partitioning system design, because the data indicated limitations in
the existing (single pass) booth configurations and other ventilation system parameters that
could be altered or otherwise optimized to further reduce the exhaust flow rate vented to the
APCS.
4.2.1 System Design Enhancements/Constraints Identified From the Baseline Study
Upon review of the Baseline Study results, it was noted that the recirculation/flow
partitioning system design should incorporate the following elements to reduce the exhaust
flow rate to the APCS down to the lowest possible level and/or ensure a safe working
environment:
1) The booth exhaust flow rate to the APCS is linearly dependent on the total booth
volume flow, and therefore is also dependent on the linear velocity maintained in the
booth. By reducing the linear flow rate through the booth to a constant 100 fpm (in
accordance with OSHA regulations codified 29 CFR 1910.94)5, a corresponding
reduction in the exhaust flow rate can be realized, which in turn can contribute
significantly to achieving the overall flow reduction goal. A constant flow rate
through the booth can only be maintained through the use of a flow adjustment system
such as that provided by variable frequency drive fans (VFDs). Thus it was concluded
40
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that the recirculation/flow partitioning system design required VFD fans, rather than
fixed drive fans that are commonly installed in most paint spray booths.
2) The Baseline Study results indicated that the Booth 2 volume flow rate was
significantly higher than is typically encountered in booths of similar cross-sectional
areas. The excessive flow rate was attributed to the open face configuration of Booth
2 in which the paint booth operator typically stood well outside of the booth enclosure.
The booth ventilation system for this configuration was therefore designed to pull a
sufficient volume of air through the booth to ensure that the 100 fpm linear velocity
required by OSHA is maintained outside of the booth (where the painter stood). As is
typical for open-faced booths, the exhaust fans in Booth 2 were drawing
approximately twice the flow volume required by OSHA if the operator was actually
located inside (rather than outside) the booth area. It was therefore concluded that
enclosing Booth 2 would result in a significant reduction in the Booth 2 volume flow
rate, which correspondingly would reduce the exhaust flow rate vented to the APCS.
3) A key system design criteria that provided an input to the mathematical recirculation
analysis is that the exhaust filter system installed on the booths must be capable of
achieving 99% collection efficiency. This is particularly true for Booths 2 and 3, in
which primers containing hexavalent chrome are routinely applied.
4) In addition, the flow rate reductions were projected based on an OSHA Factor of 0.65
for Booth 1, and 0.5 for Booths 2 and 3 in the recirculation duct upstream of where the
fresh make-up air is brought in. By projecting the recirculation rate such that the
requisite action level is achieved prior to dilution by the fresh make-up air, the design
ensures that the actual booth intake air OSHA Factor will be far less than 0.5 (In fact,
calculations suggest that the actual intake air OSHA Factor will be less than 0.3).
4.2.2 Baseline Study Conclusions and Projected Flow Reductions
The results of the mathematical analysis developed from the Baseline Study data and the
design criteria described above indicated that the exhaust flow rate vented from the MCLB
paint booths could be significantly reduced through a combination of recirculation/flow
partitioning and booth ventilation system optimization. The flow rate reductions that were
projected from the Baseline Study and system design optimization effort are summarized in
Table 7. Key conclusions derived from the baseline study include the following:
1) Measurements collected at the booth exhaust faces indicated the presence of
constituent stratification, thereby conclusively demonstrating the applicability of
recirculation/flow partitioning to the MCLB paint booths. These Baseline Study data
therefore clearly indicate that, for the MCLB booths, the flow reduction which may be
achieved using flow partitioning and recirculation is greater than the reduction
achievable via simple recirculation.
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2) The presence of hexavalent chromium in the coatings applied in Booths 2 and 3
contributed significantly to the flow reduction projections derived from the
mathematical analysis. As such, it was concluded that the exhaust filters installed as
part of the retrofit activities must achieve the highest possible filtration efficiency. As
indicated in Section 4.1.2, the calculations assumed 99%, which should be considered
the minimum acceptable filtration efficiency.
3) The Booth 1 Baseline Study data indicate that the high coating usage rate, coupled
with the organic coating constituents which are present, seem to have the greatest
impact on the Booth 1 partition height calculations.
As indicated in Table 7, the total flow rate from all three booths that was projected
based on the mathematical model is 1,541 m3/min (54,400 cfm). However, the capacity of the
APCS is limited to 1,273 m3/min (45,000 cfm), thus to achieve this exhaust flow rate, it was
necessary to place an additional constraint on the MCLB ventilation system that limits Booths
2 and 3 to sequential operation. Thus, it was decided to design and integrate the booth
ventilation systems such that Booth 1 could operate at any time, and Booths 2 and 3 could
only operate sequentially. The primary reason for this additional operating constraint is that
the MCLB booth partition height calculations were driven to a large extent by the
conservative position taken by the Marine Corps regarding the recirculation duct OSHA
Factor limits (note item 4 indicated in Section 4.2.1).
Table 7. Summary of Partition Height Calculation Results and Corresponding Flow Rate
Reductions Projected from Baseline Study.
Booth
Partition
Height
meters (feet)
Projected
OSHA Factor
Initial Booth
Exhaust Flow
Rate1
m3/min (cfm)
Final Booth
Exhaust Flow
Rate2
m3/min (cfm)
1
2.7 (8.9)
0.65
1,500 (53,000)
566 (20,000)
2
2.0 (6.7)
0.5
1,784 (63,000)
581 (20,500)
3
2.0 (6.7)
0.5
7793 (27,500)
394 (13,900)
Prior to any modifications to the Booth or the ventilation system.
Projected exhaust flow rate vented to APCS after modification. The flow rates employed in the final design
are discussed in Section 5.
The Booth 3 initial flow rate value was projected based on booth configuration information and
corresponding ventilation system estimates assuming 125 fpm linear velocity.
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4.2.3 General Comments on Recirculation with Respect to OSHA Design Mandates
The OSHA safety compliance requirements codified in 29 CFR 1910.1000 mandate
that engineering controls be implemented whenever feasible to minimize worker exposure to
hazardous compounds.7 When such controls do not fully achieve compliance, protective
equipment must be used to maintain worker exposure below the established safety levels. As
discussed in Sections 4.1.1 and 4.1.2, the Baseline Study results indicate that the Booth 1 and
2 ventilation systems provided flow rates that greatly exceeded the 100 fpm flow rate
requirements mandated in 29 CFR 1910. 94 and 107, and were therefore designed with the
maximum level of engineering controls possible.
However, the Booth 1 painter vicinity data summarized in Table 2 indicate that,
despite the significant level of engineering controls provided by the excessively high volume
flow rates, the OSHA Factor conditions in the vicinity of the paint booth operators still
exceeded unity. From the Baseline Study results, it appears that the use of engineering
controls on the MCLB booths as they were originally configured was insufficient for
maintaining acceptable working conditions, and that the use of PPE was therefore required
under original, high flow rate, single-pass (non-recirculating) conditions. This is an important
distinction, because it clearly indicates that PPE is required irrespective of whether or not
recirculation is employed, thus recirculation does not inherently require the implementation
of PPE measures as well.
4.3 RESULTS OF PRE-RETROFIT CHARACTERIZATION STUDY
A Pre-Retrofit Characterization of Booth 1 was performed in the Fall of 1995 to assess
the changes in Booth 1 operating conditions that may have occurred in the intervening two
years since the Baseline Study was completed. The Pre-Retrofit Characterization targeted key
parameters that impact Booth 1 recirculation calculations, such as constituent stratification
profiles and flow rates. Sufficient data were collected for this test series to ensure that, if
significant changes in the recirculation parameters were noted, corrected recirculation
calculations could be developed. The two critical measurements performed in the Pre-
Retrofit Characterization were exhaust flow rate (presented in Section 4.3.1) and particulate
stratification (discussed in Section 4.3.2) Details related to the Pre-Retrofit Characterization
are provided in Appendix E, which contains the a summary of the data from that study.
4.3.1 Flow Rate Variations
The Booth 1 exhaust stacks are configured such that some cyclonic flow exists at the
flow rate measurement location. Therefore, the flow rate data from both test series were
corrected for cyclonic flow to the maximum extent possible. The results of a comparative
analysis of the Booth 1 flow rates measured during the Baseline Study and the Pre-Retrofit
Characterization are summarized in Table 8. The percent difference between the average
flow rates measured during the two test series is less than 10%, which indicates that Booth 1
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operations did not changed significantly in the two years following completion of the
Baseline Study.
Table 8. Exhaust Flow Rate Data Comparative Analysis Results.
Baseline Study
m3/min (ft3/minactual)
Pre-Retrofit Characterization
m3/min (ft3/minactuaI)
Test
North
South
Total
North
South
Total
1
826
(29,183)
826
(29,182)
1,652
(58,365)
825
(29,118)
804
(28,392)
1,629
(57,510)
2
833
(29,423)
854
(30,167)
1,687
(59,590)
752
(26,553)
733
(25,869)
1,385
(52,422)
3
833
(29,402)
788
(27,827)
1,621(57,22
9)
730
(25,788)
727
(25,664)
1,457
(51,452)
4
838
(29,575)
816
(28,797)
1,654
(58,372)
695
(24,530)
751
(26,526)
1,446
(51,056)
Average'
1,654
(58,389)
Average:
1,504
(53,110)
Difference:
9%
4.3.2 Particulate Concentration Profile
A key factor considered during in the Phase 1 partition height calculations was the
hazardous constituent concentration profile at the exhaust face. Therefore, an objective of the
Pre-Retrofit Study was to assess whether or not the exhaust face concentration profile had
changed; particular emphasis was placed on the percent of the material found below the
selected partition height. The calculations derived from the Baseline Study results indicated
that the partition height should be located between the third and fourth row of filters at the
north and south exhaust faces. Therefore, the analysis compared the percent of particulate
found below each of these heights measured during the Baseline Study to the same values
obtained from the Pre-Retrofit Study. The results of this comparative analysis are
summarized in Table 9.
By inspection of the relative standard deviation data reported in Table 9 for the Pre-
Retrofit Characterization, it may be deduced that the repeatability of these results is very high.
This is also true for the Baseline Study results obtained at the north exhaust face, thus the
data from the two test series collected at the north exhaust face are representative and
therefore comparable. However, the Baseline Study south face data indicate poor
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repeatability, thus a comparative analysis of the Baseline Study and Pre-Retrofit
Characterization data sets obtained for the south face may not provide a particularly reliable
measure of variability.
As indicated in Table 9, Booth 1 particulate stratification at the key sampling
locations bracketing the partition height location did not change significantly in the time since
the Baseline Study was completed. In fact, the minor difference that is noted indicates that a
higher particulate settling rate occurred during the Pre-Retrofit Characterization. Because
this higher settling rate will only make the constituent concentrations in the recirculation
ducts lower (assuming the partition height is not adjusted), it would in turn would yield a
more conservative recirculation system (characterized by a lower recirculation duct OSHA
Factor). Thus it was decided not to adjust the partition height based on this small difference.
Table 9. Particulate Stratification Data Comparative Analysis Results.
% Particulate Below Row Centerpoint
North South
Pre-Retrofit Study
Row 3
Row 4
Row 3
Row 4
Test 1
71
57
80
74
Test 2
73
60
80
74
Test 3
72
56
83
76
Test 4
76
62
80
72
Average
73
59
81
74
Relative standard deviation (%)
2.9
4.7
2.4
2.2
Baseline Study
Test 1
65
50
84
68
Test 2
67
53
67
51
Average
66
52
60
76
Relative percent difference (%)
5.8
3.0
28
22
Comparison: Baseline Study data
vs. Pre-Retrofit Study data
(Percent Difference [%])
9.5
12
26
3.0
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SECTION 5
PAINT BOOTH MODIFICATION DESIGN ELEMENTS
The MCLB paint booth/APCS facility modification efforts completed under Phase II of
the EPA/USMC Technology Demonstration Program entailed coordination of several key system
design, integration, and operation management activities. At the initial stages of the Program, it
was recognized that implementing standard industry practices in the design phase was crucial for
facilitating technology transfer upon completion, as well as simplifying system integration to the
greatest extent possible. Thus sheet metal, structure, and ductwork design and installation
activities were executed with this goal. However, the following system elements did require a
certain level of customization:
• Constant flow rates through each booth: To minimize the exhaust flow rates from
each booth, yet ensure that the booth operates in compliance with the minimum flow
rate requirements mandated under 29 CFR 1910.94, the booth ventilation systems
were designed to operate at a constant flow rate, irrespective of the condition (e.g.
particulate loading) of the exhaust filter system.5
• Maximum performance of exhaust filter system: It was necessary to install a high
performance exhaust filtration system to minimize the deleterious effects of
particulate overspray on the APCS, as well as minimize the hexavalent chromium
concentrations in the recirculation duct.
• Coordinate paint booth/APCS system integration and interlocked operations:
Properly integrating paint booth and APCS operation via operational sequencing to
minimize system interrupts and reduce operator inconvenience was a key
consideration throughout the Phase II effort.
• Develop an efficient, fully integrated safety monitoring system - The purpose of the
safety monitoring system is to ensure compliance with applicable OSHA exposure
standards without limiting booth operating schedules or process flexibility.
These issues were of primary importance in developing an efficient and properly
integrated MCLB paint booth/APCS system, and are therefore discussed in detail in this section.
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5.1
VENTILATION SYSTEM FLOW RATE CONSIDERATIONS
At the inception of the EPA/USMC Demonstration Program, it was recognized that
minimizing the exhaust flow rates to the control device was the primary driving force for
recirculation. As the Program proceeded beyond the source evaluation efforts of the Baseline
Study (Phase I) to system design and installation (Phase II), it became evident that all potential
flow reduction strategies should be investigated to maximize the economic benefits of the
ventilation system retrofit activities. The key system options considered in this investigation are
discussed in this subsection.
5.1.1 Advantages of Flow Control
Irrespective of recirculation considerations, booth ventilation rates should be controlled
within set limits for several reasons. For instance, typical paint booth ventilation systems are
designed with fixed drive fans that are rated sufficiently high to ensure that the OSHA mandated
100 fpm requirement is met even under severe system operating conditions such as when the
exhaust and/or intake filters are heavily loaded with overspray particulate. Thus, fixed drive
fans are therefore typically sized with a large safety margin, which correspondingly produced
excessively high flow rates under "clean filter" conditions. While this approach ensures
compliance with applicable health and safety standards under all operating conditions, it also
increases the capital, installation, and operating costs of an air pollution control system (APCS),
because the capacity of the device must be sufficiently large to process the high flow rates
generated under "clean filter" conditions. Therefore, accurately controlling the booth
ventilation rates to continuously maintain the 100 fpm velocity has the beneficial effect of
reducing air pollution emission control costs.
A second reason for using recirculation and exhaust duct flow control is that it minimizes
the fan speed to the lowest safe level, and therefore also minimizes the electricity usage rate.
Thus flow control actively promotes cost effective ventilation system operation.
A third reason for controlling flow rates in recirculation/flow-partition systems is to
ensure proper and safe operation. As discussed in Section 2, flow partitioning takes advantage
of constituent stratification patterns that typically occur in paint booths to increase the
recirculation rate to the greatest extent possible. The ventilation air that passes to the APCS
therefore contains higher levels of overspray particulate, thus the filters through which the
controlled exhaust stream passes tend to become loaded more quickly than the recirculation
stream exhaust filters. This in turn causes the pressure drop across the exhaust stream filters to
increase more rapidly than the pressure drop across the recirculation stream filters. Unless the
flow rate in the recirculation and exhaust ducts are controlled, the increased exhaust filter
pressure drop will cause air flow pattern migration from the exhaust stream (below the partition)
to the recirculation stream (above the partition). This would disturb the normal overspray
stratification pattern, and potentially cause an increased concentration of hazardous constituents
in the recirculation stream. Flow control prevents an imbalance in exhaust flow through the
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filters above and below the partition.
5.1.2 Flow Control System Employed on MCLB Paint Booths
The flow rate through each booth is controlled with a feedback loop composed of a flow
measurement probe, a transmitter, a process controller, and a variable frequency drive (VFD)
equipped fan motor. The probe is located in the duct and senses the flow, then sends a
pneumatic signal to the flow transmitter. The transmitter measures the signal and relays a flow
proportional electrical signal to the process controller which compares it to the desired or
setpoint flow. The controller then decides which way the flow needs to change to maintain the
setpoint flow and communicates this electrically to the variable frequency drive, which directly
controls the fan motor speed.
To reduce costs, one feedback loop controls each booth recirculation system, which is
served by 2 discrete ducts, motors, and blowers. Each recirculation duct is served by a pair of
flow probes oriented at right angles and which are plumbed to a single transmitter that feeds one
process controller and one VFD. Each WD controls 2 motors running at identical speeds. To
ensure accurate flow, the recirculation ducts on each booth have identical configurations and
components, and equal length pneumatic lines are used to join the flow probes to the
transmitters.
Flow measurement is achieved using pitot grid array probes that are manufactured
specifically for HVAC and process flow applications. These probes deliver a signal proportional
to the square of the flow. Two probes are installed within each duct to reduce error attributed to
cyclonic flow induced by elbows, fans and other disturbances. Each flow probe pair is
connected in parallel to a pressure transmitter. Measurement errors are minimized by using high
performance pressure transmitters that typically have a combined error of less than 0.1 percent
of full scale.
The transmitters employed are the "smart sensor" type; each is equipped with a
calibration data table that is stored on the sensor by the manufacturer and which supports field
configuring. Errors for these transmitters are typically expressed as a percentage of the
configured upper range, which produces substantially lower errors than transmitters having error
rates expressed as a percentage of full range. An additional feature of the transmitters installed
on the MCLB paint booths is built-in temperature detection and correction capability. By using
these transmitters, flow measurement deviations are estimated at less than 2 percent.
The flow controller, chosen for its accuracy and operational flexibility, is an important
component of the feedback control loop. The controller receives a signal from the transmitter,
calculates the process error and generates a correction in its signal to the VFD. Of all
components in the feedback control loop, the flow controller requires the greatest effort to trim
and configure to the system operation. Loop tuning, which is required to provide smooth flow
corrections without process overshoot or undershoot, can be a long laborious process. To reduce
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loop tuning efforts, automatic (self tuning) controllers were installed on the MCLB paint booths;
this capability enabled the system programmer to quickly establish estimated values for the
proportional, integral, and derivative (PID) settings (which define the controller response
characteristics). After the approximate settings were defined, the desired characteristics were
manually adjusted. Final PID settings were established after the booths were connected to the
APCS by trimming the booth system responses to match the APCS induced draft fan
characteristics.
Although the controllers were built with many options, one proved to be absolutely
necessary. An input filter for electronically smoothing the signal from the pressure transmitter
was invaluable for stabilizing the flow signal, which (at low pressure levels [ <996 Pa (.04 inch
w.c.)] tended to cyclically deviate from the true value.
In addition, the flow controllers have the capability to accept a remote signal that adjusts
the controller setpoint. Although this feature was not used for the MCLB installation, it may be
usefitl in more complex applications for handling flow effects of multiple (>5 ) booths that
continuously cycle on and off and which are difficult to accommodate with a single control
device.
The WD components were selected to be consistent with the APCS drives. Each drive
accepts a 4-20 mA signal from the controller. Each WD is equipped with a number of
diagnostic messages on the front panel and many registers for customizing. A readout in Hz
enables the user to monitor fan speed as a function of fan flow.
5.2 SAFETY MONITORING SYSTEM
Every effort was made to design and install the MCLB booths such that, even under high
coating usage (worst case) conditions, the hazardous constituent concentrations conform with
the constraints established by Equation 2 in the recirculation dust upstream of where the fresh
make-up air is introduced. A recirculation duct monitoring system was also designed and
installed as an added safety feature. The safety system employees an FTIR to continuously
monitor the recirculation stream organic concentrations (specific information relating to the
FTIR system operation is provided in Section 2). This system assesses the quality of the
recirculation air as it exits the paint booth on a real-time basis. Booth 1 was equipped with a
dedicated safety monitoring system, and Booths 2 and 3 share a single monitoring system. This
configuration was selected because Booth 1 must be capable of full operation at all times,
whereas Booths 2 and 3 were designed to operate sequentially.
Each safety monitoring system is programmed with two alarm setpoints, or action levels,
which modify the booth operation to reduce recirculation stream constituent concentrations. If
the recirculation duct organic concentrations measured by the FTIR exceed the first action level,
the paint delivery system is shut down, which immediately curtails coating delivery to the paint
gun, and stops the release of hazardous constituents. The paint delivery system remains in the
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off mode until concentrations in the recirculation duct drop below the established set point. If
for some reason the concentration continues to increase to the second action level (such as if a
large quantity of paint is spilled in the booth, or high VOC levels flash of the workpiece), the
booth control system activates dampers to convert the booth to single-pass operation. Such
action instantly reduces the in-booth hazardous constituent concentrations. This alarm is
latched, meaning that the alarm remains in effect until a supervisor resolves its cause and then
resets the alarm. For the second action level as well as the first, the paint delivery system
remains in the off mode until concentrations in the recirculation duct drop below the established
set point.
It is anticipated that repeated excursions at the higher setpoint level will eventually be
eliminated through changes in painter practices. Typical practices that can result in excursions
include 1) pointing spray gun up toward the recirculation duct unnecessarily; 2) mixing paint
with the fans off for an extended period, thus contributing to solvent vapor build-up in the booth
before turning on the fans. After a short learning period for the painters the second level VOC
alarm, conversion to single pass, should rarely if ever, be executed.
5.3 HIGH-PERFORMANCE PARTICULATE FILTRATION REQUIREMENTS
The coating operations in Booth 2 and 3 employ small quantities of a wash primer that
contains hexavalent chromium for which, as indicated previously, a very low PEL has been
established. The Booth 2 and 3 partition height calculations were influenced to a great extent by
the potential presence of hexavalent chrome in the overspray that is directed to the recirculation
duct, thus it was deemed appropriate to employ a filtration system that achieves the highest level
of particulate control possible.
A 3-stage, high performance filtration system was selected for the MCLB application to
minimize the solid phase hazardous compound concentrations in the recirculation duct. This
decision was reached after a series of tests to determine characteristics such as pressure drop vs.
paint loading rates for various coating materials and included tests with samples of the coatings
used at Barstow.
Typical paint booth filter systems that achieve moderate filtration efficiencies are
designed with single stage media such as fiberglass or kraft paper that have clean pressure drop
readings of less than 49.8 Pa (0.2 inch w.c.), and which are replaced when the pressure
differential across the media reaches 249 Pa (1 inch w.c.). However, high-efficiency, multi-
stage filters tend to have relatively higher clean pressure-drop readings, and are also somewhat
more expensive than traditional filter systems. As such, there is an economic incentive to drive
the filters to a reasonably high pressure drop prior to replacement.
However, establishing a reasonable filter life cycle involves the consideration of several
related factors. For instance, less frequent filter replacements require higher pressure
differentials which in turn require higher fan and motor capacities as well as sturdier, heavier
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exhaust plenums, ducting, and dampers. One of the first tasks executed under the Phase II effort
was to establish the limits of the MCLB paint booth exhaust plenums, as well as the selected 3-
stage high efficiency filter system. The results of this evaluation indicated that the plenums are
capable of withstanding a 622.5 Pa (2.5 inch w.c.) pressure drop, whereas the filters can easily
handle a 17.4 Pa (.7 inch w.c.) or more pressure drop.
The operating life of each stage of the-3 stage filter system varies not only as a function
of the filter material, but also as a function of other qualitative and quantitative painting
parameters.They include such workplace characteristics as workpiece configuration, aerosol size
distributions, coating transfer efficiency and dropout, and operator habits, etc. To establish the
replacement frequency of each of the filter stages in the MCLB paint booths, two representative
filter elements were selected (one above the partition in the recirculation zone, and one below
the partition in the exhaust zone), and pressure differential gages were installed across each
stage of these representative elements. The elements were selected to reasonably represent the
median particulate loading level in each of the two zones. By installing a static pressure probe
between stages 1 and 2 and one between stages 2 and 3 and referencing these to booth and
plenum pressures, respectively, three discrete pressure signals are available from each
representative element. The probes are connected to manometer gages mounted on the exterior
of the booth, thus providing a means of measuring the pressure differential across each stage.
These gages provide information for determining whether the first, second, or third stage needs
replacing when the overall pressure exceeds 2.0 inch w.c.
Clean filter pressure drop is directly proportional to the linear face velocity through the
filter. Therefore, controlling the flow rate through each booth produces the added benefit of
reducing the clean pressure drop insofar as possible. For booths 2 and 3, the face velocities
through the exhaust filters is 134 fpm, which corresponds to a clean filter pressure differential of
approximately 0.5 inch w.c. across all three stages. The original Booth 1 exhaust face was
configured such that, even with the flow rate reductions achievable by flow control, a 200 fpm
face velocity would be generated after the retrofit modification. This was considered too high to
achieve reasonable filter replacement intervals, thus the exhaust system was redesigned to
accommodate an additional row of filters. This successfully reduced the linear face velocity
through the Booth 1 exhaust filters to 167 fpm, which corresponds to a clean filter pressure
differential 0.87 inch w.c.
For each booth, the pressure gages provide input to the booth control panel, and notifies
the operator of impending filter replacement requirements via a 2-level warning system. The
first level is triggered at a 2.0 inch w.c. pressure drop, and notifies the operator to schedule a
filter change. The second level, which occurs at 2.5 inch w.c., disables the booth fans, thereby
maintaining a reasonable pressure differential in the plenums and ductwork. This 0.5 inch
margin was provided in an effort to reasonably extend filter life and minimize operating costs.
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5.4 FINAL FLOW RATES
As discussed in Section 4, the results of the Baseline Study indicated that significant flow
reductions could be achieved for the MCLB paint booths. The initial, projected, and actual
booth exhaust flow rates achieved are summarized in Table 10. The initial volume flow rate
data and the flow reductions projected from the Baseline Study results are discussed in detail in
Section 4. The data presented in Table 10 in the Final Configuration column reflect actual
operating conditions that currently exist and which were established as a result of the Phase II
retrofit efforts (described in detail above).
Table 10. Summary of Volume Flow Rate Reductions Achieved for MCLB Paint Booths
Booth
Initial Volume
Flow Rate
m3/min (cfm)
Projected from Baseline Study1
Final Configuration
Overall
Percent Flow
Reduction
Achieved
Volume Flow
m3/min (cfm)
Exhaust Flow
m3/min (cfm)
VolumeFlow
m3/min
(cfm)
Exhaust Flow
m3/m (cfm)
1
1,500 (53,000)
1,019 (36,000)
566 (20,000)
962 (34,000)
572 (20,210)
62%
2
1,783 (63,000)
906 (32,000)
580 (20,500)
906 (32,000)
604 (21,330)
66%
3
778 (27,500)
623 (22,000)
393 (13,900)
623 (22,000)
415 (14,660)
47%
Total
4,061 (143,500)
2,547 (90,000)
1,539 (54,400)
2,490 (88,000)
1,176 (41.540)2
71%2
1 Details provided in Section 4.
2 The APCS installed at the Barstow facility has a maximum rated capacity of 1274.4 m3/min (45,000
cfm), therefore Booths 2 and 3 were configured for sequential operation only. For this reason, the
maximum volumetric flow rate vented to the APCS does not exceed 1,176 m3/min (41,540 cfm).
However the macimum reduction capability is 1274.4 m3/min (45,000 cfm).
The significant flow reduction achieved in the MCLB paint booth retrofit efforts is
attributed to the following design factors:
1) FLOW CONTROL By using the VFDs to control air flows, a constant flow rate is
maintained in each booth, which ensures compliance with OSHA requirements while
minimizing exhaust flow rates. 32% of the flow reduction achieved is attributed to
the flow control feature.
2) RECIRCULATION/FLOW-PARTITIONING Through installation and operation of
recirculation/ flow-partitioning, the exhaust flow rate to the APCS was reduced by an
additional 31%. Note that the level of flow reduction achieved by recirculation/flow
partitioning was limited primarily by the conservative EPA/MCLB decision to
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establish large safety margin for the recirculation duct OSHA Factor. Greater flow
reductions may be achieved via recirculation for facilities that either employ more
stringent protective equipment, or do not adopt an approach that is not quite so
conservative.
3) BOOTH 2 ENCLOSURE As discussed in Section 4, Booth 2 was originally
configured as an open face booth, and therefore operated at a significantly higher
flow rate than is necessary for a fully enclosed booth of similar size. By enclosing
Booth 2, the flow rate vented to the APCS was reduced by an additional 23%.
4) FLOW MANAGEMENT By alternating the operating schedules for Booths 2 and 3,
the volumetric flow rate vented to the APCS was reduced an additional 14%. The
sequential operation of Booths 2 and 3 is controlled from a single interface panel.
Although each booth is internally equipped with full operation capabilities, the
circuitry is designed such that only one booth can be run at a time. The operating
booth is selected via a front panel switch, which is locked for supervisor control. The
safety monitor is devoted to whichever booth is operating, and the sample inlet
direction is controlled with a three-way valve connected to the panel mounted switch.
5.5 PAINT BOOTH/APCS SYSTEM INTEGRATION REQUIREMENTS
The MCLB paint booth operating schedules are frequently demanding and generally
variable. The two booth areas, Area 11 (Booths 2 and 3) and Area 18 (Booth 1) are managed by
different supervisors. Booths 2 and 3 are designed for sequential operation (i.e. these booths
cannot be operated simultaneously) due to flow capacity of the APCS. Given the process
constraints and area management structure, the importance of adequately linking booth
ventilation systems with APCS operation was apparent from the initial stages of Phase II. To
develop the necessary system coordination procedures and handshake signals between the booths
and the APCS, various startup and operation strategies were identified through a detailed "what
if' analysis.
The startup strategy was developed based on the premise that the booths and the APCS
form an integrated process, thus all painting operations rely on proper functioning of the APCS.
Booth operators must be able to detect at a glance whether the APCS is available for service, or
is down for maintenance. After this is determined, and the start button is pressed, startup
becomes a series of automatically executed steps that include several system condition tests.
The booth ventilation system and APCS operations are activated only after these checks are
satisfactorily completed to ensure simultaneous, smooth, and safe system integration. The
following summarizes the integrated system sequence of operation:
1) The "APCS Ready" signal, sent from the APCS control network, indicates the
availability of the APCS for booth service. The "APCS Ready" light on each booth
53
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control panel is illuminated when this signal is received. The booths can not be
started until this signal is received.
2) If the "Start" button on the control panel is pressed and no fan overload conditions
are sensed, the variable frequency drives (VFDs) power up and the "Start Sequence
Enable" light is illuminated. At this stage, booth fans remain immobile.
3) When the "Start Permissive" signal is received from the APCS and the indicator light
is illuminated, the recirculation fans are sent a "Run" (forward) command. The
"Start Permissive" signal is controlled by the APCS network to properly coordinate
APCS operation with booth exhaust fan activation.
4) The exhaust duct dampers also open when the "Start Permissive" signal is received
by the booth control panel. When system is shut down, the exhaust dampers close
after a time delay.
5) Fan speed is locally controlled by a feedback loop containing a pitot array velocity
probe, a pressure transmitter, a process controller, and a VFD. A separate velocity
probe is provided in each recirculation duct; for each booth, these probes share a
common transmitter, process controller, and VFD drive. The controller is
programmable and is capable of remote setpoint control should this be required for
additional control via the APCS network.
6) In the event that a high pressure differential (2.0 inch w.c.) across the exhaust filter is
detected, both a filter maintenance warning light and an audible alarm signal are
activated.
7) In the event that the highest level pressure differential (2.5 inch w.c.) across the
exhaust filter is detected, the booth system is shut down, the WD is disconnected
from the power sources, a filter shutdown indicator is lit, and both an audible alarm
and a visible beacon are activated.
8) If the recirculation VFD is operating properly, the "Recirculation Fans Running" light
is illuminated.
9) If the recirculation VFD is running and the "Exhaust Damper Limit Switch" is closed,
then the exhaust VFD is started.
10) If the exhaust VFD is operating properly, the "Exhaust Fan Running" light is
illuminated.
11) If normal VOC levels are present and a personnel access door is opened, a timer
starts. If door is not shut within the time setting (approximately 1 minute), a solenoid
valve shuts off paint flow.
12) A high VOC level triggers the "High Solvent Concentration Level 1" light. This light
54
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is switched via the safety monitor, and paint supply is shut off. The monitor system
is designed to automatically clear this condition once VOC levels return to normal.
This strategy was devised so that only minimum production delays are experienced.
13) A maximum VOC level triggers the "High Solvent Concentration Level 2" event in
which the monitor latches, the paint air supply is shut off, and the recirculation air is
vented to the outside (which converts the booth ventilation system to single-pass
operation). The alarm controller also activates a siren, a flashing beacon, and a
lighted alarm indicator. The alarm is latched and may be cleared only by manual
interface with the safety monitor. Only authorized personnel have access to the
monitor to clear the signal; this allows a review of the conditions that initiated the
alarm.
14) For diagnostic purposes, a number of signals are relayed to the APCS control computer
for storage and historical trends. These signals include:
- Exhaust flow rate
- Recirculation flow rate
- Booth temperature
- Exhaust filter pressure drop
- Recirculation filter pressure drop
- Booth in single pass mode
- Booth emergency stop
15) An additional control signal was provided to prevent low flow rate conditions caused by
loose drive belts. The APCS computer compares the flow rate signals that are received
from an on-line booth. If the flow rate is below the established setpoint by 20 percent or
more, it engages a "low flow" alarm on the booth. This ensures that the booths always
operate in compliance with the 100 fpm (30.5 m/min) linear velocity mandated under 29
CFR 1910.94 for spray booth operation.5
16) If a booth control panel has power, no alarms are engaged, and compressed air is
available, the emergency stack damper is closed, the recirculation dampers are open, and
the booths proceed to operate in recirculation mode. If a booth panel requires powering
down for maintenance, the dampers must be placed in "maintenance mode" via manual
valves to force them closed.
17) If the "fire suppression alarm" is triggered, power to the booths is shut off, and dampers
adjust to their "fail open" conditions. The fire suppression panel controls its own audible
and visible alarms. In all other respects, the fire suppression system is independent of the
operation of the booths.
55
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SECTION 6
TECHNOLOGY DEMONSTRATION STUDY RESULTS
Following the Phase II design, fabrication, and installation of the spray booths, Phase III
of the program including system testing and evaluation activities was initiated. The objective of
the Phase III effort was to determine if the recirculation/flow partition systems installed in a
production environment behaves mechanically, and functionally as predicted. Thus, it was
necessary to confirm that the constituent concentrations in the recirculation duct are below the
established safety level, and that recirculation has little impact on constituent concentrations in
the vicinity of the paint booth operator. Vicinity sampling results are particularly important, as
they provide an indication of the operational compliance status with respect to OSHA exposure
requirements. Supplemental data pertaining to vapor and solid phase concentration profiles at
the exhaust face of each booth were also collected in the event that adjustments in the partition
height was required at a later date. The test matrix that was developed and implemented for the
Phase III Demonstration Study is summarized in Table 11. The results of these tests are
provided and discussed in this Section.
6.1 HAZARDOUS CONSTITUENT CONCENTRATIONS MEASURED UPSTREAM
OF FRESH MAKEUP AIR INTAKE IN THE RECIRCULATION DUCTS
6.1.1 Measurement Objective and Results
As discussed in detail in Section 4, the results of the Phase I Baseline Characterization
Study were used to estimate the appropriate partition heights and corresponding recirculation
rates for each of the three MCLB paint booths. These estimates were developed based on the
premise that the concentrations in the recirculation duct upstream of the fresh make-up air intake
must conform with the OSHA Factor restriction imposed by Equation 2. Correspondingly, the
objective of the recirculation duct measurements described here was to confirm whether or not
these partition height/recirculation rate estimates were correct. This was accomplished by
determining the constituent concentrations (and corresponding OSHA Factors) in the
recirculation duct upstream of the fresh make-up air intake. Details relating to the sampling and
analysis procedures employed for these measurements are summarized in Appendices A and B,
respectively.
The results of the recirculation duct concentration measurements and OSHA Factor
calculations for Booths 1,2 and 3 are summarized in Tables 12 through 14. The hexavalent
chrome data reported in Tables 13 and 14 have been blank-corrected, as well as the HDI results
reported for Booths 1 and 2. Details pertaining to these analytical correction procedures are
included in the Quality Assurance/Quality Control (QA/QC) discussion provided in Section 9.
More detailed information relating to the OSHA Factor calculations for each of the recirculation
duct sampling events is provided in Appendix D.
56
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Table 11. Test Matrix for Demonstration Study.
Objective
Location
Parameter
Sampling Method
Booth 1
Determine recirculation
duct concentrations
Recirculation
ducts
Metals
Isocyanates
Speciated organics
Total organics
Flow rate
EPA Method 006012
EPA Method 006117
EPA Draft Method18
NIOSH 130010
EPA Method 25 A14
EPA Method 216
Establish OSHA Factor
in the vicinity of the
paint booth operators
Vicinity of paint
booth operators
Metals
Isocyanates
Speciated organics
NIOSH 73008
OSHA 427
NIOSH 130010
Determine exhaust face
concentration profile
Exhaust faces
Metals
Speciated organics
NIOSH 73008
NIOSH 130010
Booth 2
Determine recirculation
duct concentrations
Recirculation
ducts
Metals
Isocyanates
Speciated organics
Total organics
Phosphoric Acid
Flow rate
EPA Method 006117
EPA Draft Method18
NIOSH 130010
EPA Method 25 A16
NIOSH 790318
EPA Method 216
Establish OSHA Factor
in the vicinity of the
paint booth operators
Vicinity of paint
booth operators
Metals
Isocyanates
Speciated organics
Phosphoric acid
NIOSH 73008
OSHA 427
NIOSH 130010
NIOSH 790318
Determine exhaust face
concentration profile
Exhaust faces
Metals
Speciated organics
NIOSH 73008
NIOSH 130010
Booth 3
Determine recirculation
duct concentrations
Recirculation
ducts
Metals
Isocyanates
Speciated organics
Total organics
Phosphoric acid
Flow rate
EPA Method 006117
EPA Draft Method18
NIOSH 130010
EPA Method 25A16
NIOSH 790318
EPA Method 216
Establish OSHA Factor
in the vicinity of the
paint booth operators
Vicinity of paint
booth operators
Metals
Isocyanates
Speciated organics
Phosphoric acid
NIOSH 73008
OSHA427
NIOSH 130010
NIOSH 790318
Determine exhaust face
concentration profile
Exhaust faces
Metals
Speciated organics
NIOSH 73008
NIOSH 130010
57
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Table 12. Booth 1 Recirculation Duct Constituent Sampling Results.
Test 1
Test 2
Test 3
Test 4
Test 5
Test 6
North
South
North
South
North
South
North
South
North
South
North
South
Concentrations (mg/m3)
Trivalent chromium
0.0042
0.0046
0.0142
0.0050
ND
0.0075
0.003
0.0039
0.0045
0.0059
0.0022
0.0047
HDI
0.0015
0.0014
0.0015
0.0015
0.0015
0.0014
0.0015
0.0015
0.0015
0.0015
0.0015
0.0015
Methyl ethyl ketone
18
28
13
27
16
21
13
18
7.9
11
1.8
11
Ethyl acetate
0.26
0.30
0.21
0.26
0.32
0.23
0.2
0.24
0.18
0.18
0.26
0.25
Methyl isobutyl ketone
33
50
23
50
31
40
28
47
33
48
7.2
39
Toluene
41
61
29
63
38
50
28
44
29
42
8.7
47
Butyl acetate
20
30
14
31
17
22
12
20
11
17
3.4
19
Methyl isoamyl ketone
22
35
16
38
4.8
0.23
3
5
1.3
2.1
0.42
2.5
Ethyl benzene
19
29
13
30
17
23
12
21
14
20
4.2
23
Total xylenes
100
150
69
158
90
121
64
110
73
110
22
120
Trimethyl benzene
4.3
6.3
2.9
7.1
3.5
6.3
2.9
4.7
2.9
4.4
0.94
4.9
Hexyl acetate
6.5
9.5
4.6
11
5.2
7.4
4
6.6
2.4
3.7
0.8
4.5
OSHA Factor upstream of
fresh make-up air intake
0.76
0.71
0.60
0.53
0.52
0.40
OSHA Factor in ventilation
air introduced to Booth 1
0.31
0.29
0.25
0.22
0.21
0.16
-------
Table 13. Booth 2 Recirculation Duct Constituent Sampling Results.
Test 1
Test 2
Test 3
Test 4
Test 5
Test 6
North
South
North
South
North
South
North
South
North
South
North
South
Concentrations (rag/m3)
HDI
0.0015
0.0015
0.0015
0.0015
0.0015
0.0015
0.0015
0.0015
0.0015
0.0015
0.0015
0.0015
Phosphoric acid
0.0203
0.026
0.027
0.03
0.026
0.029
0.026
0.027
0.026
0.026
0.026
0.025
Hexavalent Chromium
0.0011
0.0004
5.4E-5
5.4E-5
5.6E-5
7.0E-5
0.0002
0.0014
3.8E-4
2.8E-5
1.3E-5
5.3E-5
Methyl ethyl ketone
15
12
8.4
8
14
13
19
9.3
25.6
17
27
16
Ethyl acetate
0.12
0.11
0.13
0.13
0.13
0.48
0.38
0.13
0.18
0.22
0.34
0.32
n-Butanol
5.1
5.1
3.3
6
5.3
7.4
12
7.8
7.6
6.0
19
6.8
Methyl isobutyl ketone
12
8.1
7
8.1
11
15
15
7.9
15
8.7
18
8.3
Toluene
16
12
9.4
14
14
19
19
12
22
14
32
16
Butyl acetate
10
6.6
4.8
5.5
30
39
39
20
14
8
19
8.7
Methyl isoamyl ketone
0.12
0.11
0.13
0.13
0.13
0.13
0.13
0.13
0.13
0.13
0.13
0.13
Ethyl benzene
5.9
4.0
3.5
4
3.5
4.6
4.5
2.4
7.2
4.1
9.2
4.1
Total xylenes
30
21
18
21
24
31
30
16
37
21
47
21
Trimethyl benzene
4.8
3.5
2.8
3.5
4.1
5.1
5.4
3.1
6.1
3.5
8.8
3.7
Hexyl acetate
7
4.9
3.2
3.5
5.6
6.4
6
3.2
8.3
4.4
12
5.2
OSHA Factor upstream of
fresh make-up air intake
1.07
0.28
0.41
1.07
0.68
0.50
OSHA Factor in ventilation
air introduced to Booth 2
0.28
0.07
0.11
0.29
0.18
0.14
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Table 14. Booth 3 Recirculation Duct Constituent Sampling Results
Test 1
Test 2
Test 3
Test 4
Test 5
Test 6
East
West
East
West
East
West
East
West
East
West
East
West
Concentrations (mg/m3)
HDI
0.0022
0.0017
0.0025
0.0022
0.022
0.0022
0.0025
0.0029
0.0024
0.0027
0.0015
0.0019
Phosphoric acid
0.021
0.021
0.024
0.024
0.024
0.025
0.025
0.025
0.023
0.027
0.021
0.027
Hexavalent chromium
0.0004
5.1E-5
0.0001
5.1E-5
0.0002
5.0E-5
5.4-E5
9.2E-5
5.4E-5
4.8E-5
0.0001
4.7E-5
Methyl ethyl ketone
2.4
2.1
2.6
2.3
3.9
2.4
3.2
0.3
6.6
5.6
6.9
5.6
Ethyl acetate
0.15
0.23
0.12
0.25
0.25
0.25
0.13
0.23
0.13
0.33
0.20
0.34
n-Butanol
0.83
0.6
2.2
1.2
0.83
0.65
0.95
0.39
1.6
0.88
0.80
0.89
Methyl isobutyl ketone
0.57
0.48
1.1
0.95
1.6
1.0
1.6
0.13
2.0
1.3
0.87
1.3
Toluene
1.1
1.6
2.5
3.4
4.5
7.4
5.2
2.8
6.1
8.6
3.1
8.7
Butyl acetate
0.58
0.5
1
0.89
1.4
0.95
1.4
0.13
1.2
0.81
0.63
0.82
Methyl isoamyl ketone
0.1
0.11
0.12
0.12
0.12
0.12
0.13
0.13
0.13
0.13
0.13
0.13
Ethyl benzene
0.27
0.23
0.57
0.48
0.81
0.55
0.82
0.13
1.2
0.9
0.67
0.91
Total xylenes
1.4
1.2
3.0
2.5
4.3
3.0
4.3
0.13
6.7
4.9
3.4
3.1
Trimethyl benzene
0.69
0.41
0.64
0.54
0.69
0.5
0.77
0.26
0.59
0.45
0.33
0.46
Hexyl acetate
0.1
0.58
0.85
0.72
0.12
0.83
1.3
0.13
1.0
0.72
0.34
0.73
OSHA Factor upstream of
make-up air intake
0.31
0.20
0.25
0.20
0.20
0.19
OSHA Factor in ventilation
air introduced to Booth 3
0.11
0.07
0.09
0.07
0.07
0.07
-------
The coating usages recorded during each test are indicated in Table 15. Note that,
because the test results were intended to reflect maximum coating usage rates for worst case
(highest OSHA Factor) conditions, the paint application rates recorded are much higher than
typically occur at the MCLB facility. There was some concern that perhaps the Booth 2 test
conditions during the recirculation test series were excessive, thus additional coating usage data
which reflect typical Booth 2 operations were also collected. This "standard coating usage rate"
data for Booth 2 are also summarized in Table 15.
6.1.2 Implications of Recirculation Duct Sampling Results
As indicated in Tables 12 through 14, the quality of the respirable air introduced into the
MCLB paint booths as determined from the recirculation duct sampling results conforms with
the health and safety requirements mandated by OSHA and codified in 29 CFR 1910.1000.7
Additional conclusions from Tables 12 through 14 results include the following:
• Despite the fact that a high efficiency, 3-stage particulate filtration system was
installed on all the booths, there were still traces of hexavalent chrome measured in
the booth 2 and 3 exhaust streams. Because hexavalent chrome can be a major
contributor to the OSHA Factor summation equation (ranging from 15 to 87
percent), the presence of this compound has a significant impact on the magnitude of
the OSHA Factors reported in Tables 13 and 14. The filter manufacturer claims that
the presence of hexavalent chrome is due to leakage around the filter frame (at the
point of attachment to the third stage of the filter) and is currently exploring design
changes. The fact remains that hexavalent chrome was measured in the recirculation
ducts, and therefore did impact the Booth 2 and 3 OSHA Factor results.
[Note: Metal samples from the Booth 2 and 3 recirculation ducts were collected in
accordance with EPA Method 0061for hexavalent chrome. Metal samples in the
Booth 1 recirculation ducts were collected in accordance with EPA Method 0060for
total chrome. Hexavalent chrome in not used in booth 1.]
• The source of hexavalent chrome in the CARC paint system is the wash primer
material, which is typically used in small quantities in Booths 2 and 3. As noted in
Section 6.1, a high wash primer usage rate was imposed for the Booth 2 recirculation
tests to ensure that booth 2 results represented worst case conditions. The paint usage
data reported in Table 15 indicate that the average wash primer usage during the 1
hour recirculation duct tests was 17 kg, however typical booth 2 production levels
require only 2.3 kg of wash primer per hour of operation. Thus, the booth 2
recirculation test results indicate that the 0.5 OSHA Factor target level in the
recirculation duct upstream of where it is diluted with fresh make-up air will only be
slightly exceeded (to 0.67), even when the throughput rate is seven times higher than
typical production levels. Moreover, due to the dilution effects of the fresh make up
air that is mixed with the recirculated air, the quality of the paint booth intake air
(comprised of recirculation air + fresh make-up air) does not exceed the target 0.5
OSHA Factor.
61
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Table 15. Paint Usage Rates Recorded during Painter Vicinity OSHA Factor Measurements.
Location
Condition
Painter 1
Painter 2
Total
Booth 1
Single-Pass
Test 1
21.33 kg
26.15 kg
46.61 kg
Both painters apply topcoat +
Operation
Test 2
25.28 kg
22.98 kg
49.13 kg
thinner only
Test 3
19.94 kg
18.32 kg
38.26 kg
Average
22.3 kg
44.67 kg
Recirculation
Test 1
28.29 kg
20.67 kg
48.96 kg
Operation
Test 2
22.79 kg
31.00 kg
53.79 kg
Test 3
28.36 kg
26.13 kg
54.67 kg
Test 4
20.33 kg
24.55 kg
44.88 kg
Test 5
26.23 kg
29.47 kg
55.70 kg
Test 6
15.90 kg
31.06 kg
46.96 kg
Average
25.41 kg
50.87 kg
Booth 2
Single-Pass
Test 1
3.76 kg
22.00 kg
25.76 kg
Painter 1:
Operation
Test 2
4.39 kg
46.35 kg
50.74 kg
primer only
Test 3
14.59 kg
24.76 kg
39.35 kg
Painter 2:
Average
7.58 kg
31.04 kg
38.62 kg
topcoat + thinner
Recirculation
Test 1
17.27 kg
20.43 kg
37.7 kg
Operation
Test 2
12.29 kg
30.64 kg
42.93 kg
Test 3
19.97 kg
17.66 kg
37.63 kg
Test 4
23.04 kg
35.35 kg
58.39 kg
Test 5
14.20 kg
13.36 kg
27.56 kg
Test 6
15.36 kg
20.43 kg
35.79 kg
Average
17.02
22.98 kg
40.00 kg
Booth 2 Coating Usage in a Typical 2-Hour
Wash Primer Usage:
Topcoat Usage :
Painting Cycle (i.e. typical 2 hour operation)
4.6 kg / 2-hrs
11.39 kg/2-hrs
Booth 3
Single-Pass
Test 1
2.70 kg
7.07 kg
9.77 kg
Painter 1: primer use
Operation
Test 2
4.06 kg
7.48 kg
11.54 kg
Painter 2: topcoat + thinner use
Test 3
5.16 kg
2.73 kg
7.89 kg
Average
3.97 kg
5.76 kg
9.73 kg
Recirculation
Test 1
6.15 kg
6.29 kg
12.44 kg
Note: only one painter is
Operation
Test 2
6.91 kg
4.71 kg
11.62 kg
present in booth 3; the painter
Test 3
6.15 kg
4.71 kg
10.86 kg
continuously shifts from primer
Test 4
8.05 kg
4.71 kg
12.76 kg
to topcoat application
Test 5
4.61 kg
7.67 kg
12.28 kg
Test 6
4.61 kg
7.64 kg
12.25 kg
Average
6.08 kg
5.96 kg
12.04 kg
62
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• The goal of maintaining hazardous concentrations in the recirculation duct at a
location upstream of the fresh makeup air intake near the level established by
Equation 2 was met for 12 of the 17 individual measurements. The average OSHA
Factor measured in the Booth 1 recirculation ducts prior to mixing with the fresh
make-up air was 0.59, which is slightly above the 0.5 target value. The calculated
OSHA Factor is further reduced to 0.24 at the booth intake due to dilution by the
fresh make-up air. Note however that the high production throughput under which
the Booth 1 recirculation duct measurements were collected represent extreme,
worst-case conditions which are atypical for this facility. Thus the OSHA Factor in
the recirculation duct under normal operating conditions will remain well below the
0.5 setpoint level, and the quality of the Booth 1 intake air determined from the
recirculation duct data will remain below 0.25.
• As indicated in the results presented in Table 14, it appears that the assumptions
employed to estimate the proper partition height for Booth 3 were conservative.
Recall that the objective for the Booth 3 design was to achieve an OSHA Factor of
0.5 in the recirculation duct; however, the OSHA Factors obtained from the Booth 3
recirculation duct measurements are somewhat lower.
• It is important to note that the OSHA PELs employed to derive the recirculation duct
and dilution stream OSHA Factors reported in Tables 12 through 14 are 8 hour
TWAs. Thus, the results are conservative since the OSHA Factor results assumes
that the paint booth operators apply paint in the booths for 8 hours per day which is
not the case. The typical painting intervals (the hours per day that paint is actually
sprayed) do not exceed 4-5 hours per day. Therefore, actual recirculation duct and
dilution stream OSHA Factors are at least 25% lower than those reported in Tables
12 through 14.
The recirculation duct and dilution stream OSHA Factors reported in Tables 12 through
14, coupled with the safety margins implicit in their derivation, clearly indicate that the MCLB
recirculation/flow partition systems operate well within the health and safety limits mandated by
OSHA under 29 CFR 1910.1000.7
6.2 EXHAUST FACE CONSTITUENT CONCENTRATION PROFILE RESULTS
The partition heights and recirculation rates were determined for each booth using
conservative assumptions regarding hazardous constituent concentrations in the recirculation
stream. The initial design criteria specified that the recirculated concentrations conform with
the Equation 2 summation rule upstream of where the recirculation concentrations are diluted by
fresh make-up air. The resulting ventilation systems that were installed create working
conditions that conform with OSHA health and safety limits by a wide margin. If, in the future,
MCLB staff members elect to re-evaluate this particular design criteron, and perhaps alter one or
more of the booths to increase the recirculation rate, it will be necessary to recalculate the
63
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to the solid and vapor phase compound concentration profiles for each exhaust face. Thus, these
data will be required in the event that MCLB subsequently modifies the booth recirculation
systems in any way.
In an effort to provide supplemental information to MCLB and thereby facilitate future
system modification activities, a key effort under the Phase III Demonstration Study was to
profile the solid and vapor phase constituent concentrations across the exhaust face of each
booth. These profile measurements provide relative concentration data for metal and organic
vapor compounds at various heights across the exhaust filter for each booth. The test parameters
were developed based on the assumption that metal and organic concentration measurements
would provide representative solid and vapor phase profiles, respectively.
Results of the aggregate metal concentration measurements as a function of height for
Booths 1, 2 and 3 are indicated in Tables 16 through 18, respectively, and the total organic
concentration results are summarized in Tables 19 through 21, respectively. The metal and
organic data are also presented graphically Figures 12 through 14. The graphs defines the basis
for determining the percentage of pollutant that must be removed in the partition stream and the
corresponding partition height. These data can therefore be directly applied as inputs to Equation
7 to develop alternative partition height scenarios. Note that Tables 16 through 21 provide
summary information only; detailed information relating to the actual constituent concentrations
measured at each location are provided in Appendix D.
6.3 HAZARDOUS CONSTITUENT CONCENTRATIONS IN THE VICINITY OF
THE PAINT BOOTH OPERATOR
6.3.1 Measurement Objective and Results
In typical paint spray operations, the pattern created by the spray nozzle coupled with the
target configuration and the booth air flow dynamics tend to combine in such a way that the
painter frequently operates in a "cloud" of overspray particulate and solvent vapor.8 As such, the
hazardous constituent concentrations generated by non-recirculating booths in the immediate
vicinity of the painter often exceed the OSHA Factor level defined by Equation 1 in Section 2.
To ensure that the impact of recirculation on the constituent concentrations in the painter vicinity
is negligible (i.e., recirculation does not contribute to this "cloud effect"), the paint booth
partition heights were selected to maintain the quality of respirable air well below the safety
limits established by OSHA. As indicated in the results summarized in Section 6.2, the partition
heights and recirculation rates successfully maintain the concentrations in the intake air well
below these limits.
To conclusively demonstrate the negligible impact of recirculation on the working
environment in the paint booth, samples were collected in each booth in the vicinity of the paint
booth operators. Two sets of measurements were collected for each booth in separate test series.
In the first series, samples were collected in the vicinity of the painter while the booth operated in
single-pass mode (without recirculation) to establish booth operating conditions created by the
cloud effect in the vicinity of the painter in the absence of recirculation. For the second test
64
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in single-pass mode (without recirculation) to establish booth operating conditions created by the
cloud effect in the vicinity of the painter in the absence of recirculation. For the second test
series performed after booth modifications were completed, constituent concentration
measurements were again collected in the vicinity of the painter while the booth was operated in
recirculation mode.
For each test series, three sets of samples were collected for each class of compound
measured. It was not possible to collect all the samples required for each booth in a single
sampling run, thus for each booth, the three data sets were collected over six painting cycles. To
provide a means of effectively correlating these results, the amount of coating used during each
sampling event was also measured; these data are summarized in Table 15.
The painter vicinity test results obtained from the single-pass operating mode for Booths
1,2, and 3 are presented in Tables 22,23, and 24, respectively. Similar data obtained from the
recirculating operating mode for Booths 1,2, and 3 are presented in Tables 25, 26, and 27,
respectively. Each table summarizes the painter vicinity concentrations measured during the
single-pass mode and recirculation mode tests, and the corresponding painter vicinity OSHA
Factor which was derived from Equation 1. Note that the OSHA Factor derived in this way does
not in any way reflect the painter's actual exposure during the sampling event.
The data input to the summation equation were collected outside the respirator hood in
the vicinity of the painter's breathing zone, and therefore do not include the protection factor
provided by the personal protection equipment worn by the operator during painting. To
estimate the OSHA Factor related to the painter's exposure, the value determined for the painter
vicinity OSHA Factor was divided by the respirator protection factor assigned in accordance
with OSHA guidelines. Note that, because the painters operating in Booth 1 often wear
cartridge-type respirators (which are assigned a protection factor of 10) rather than hooded air-
line respirators (which are assigned a protection factor of 25), both of these factors are reflected
in Tables 22 and 25.
In comparing the Booth 2 painter vicinity chromium concentration results from the
Baseline Study (provided in Section 4) to the painter vicinity chromium results obtained from
the Technology Demonstration Study, it becomes immediately apparent that the Booth 2
modifications significantly reduced painter vicinity metal concentrations. As indicated in Table
5, the average painter vicinity chrome concentration prior to the Booth 2 modifications ranges
from 0.024 mg/m3- 0.106 mg/m3, with an average of 0.095 mg/m3. Similar results from the
Technology Demonstration Study indicate that the Booth 2 painter vicinity total chrome
concentration ranges from 0.002 mg/m3 to 0.022 mg/m3, and averages 0.0073 mg/m3.
This data conclusively demonstrates that the Booth 2 modifications significantly
enhanced the ventilation system performance, and greatly improved the working conditions in
the booth in terms of the health and safety requirements mandated by OSHA. These
enhancements are doubtlessly due to the combined effect of enclosing Booth 2 and using the
VFDs to create a consistent and uniform flow profile within the booth.
65
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Table 16. Booth 1 Average Chrome Concentrations at Specific Exhaust Face Heights.
Height
m (ft)
Test 1
(mg/m3)
Test 2
(mg/m3)
Test 3
(mg/m3)
Average
(mg/m3)
4.4 (14.4)
0.0067
0.0030
0.0064
0.0054
3.9 (12.7)
0.060
0.0047
0.011
0.025
3.3(11.0)
0.016
0.0062
0.020
0.014
2.8 (9.3)
0.040
0.021
0.0091
0.023
2.3 (7.6)
0.051
0.013
0.055
0.040
1.8 (5.9)
0.056
0.017
0.022
0.032
1.3 (4.2)
0.082
0.0078
0.023
0.038
0.76 (2.5)
0.054
0.0069
2.1
0.72
0.024 (0.8)
0.024
0.0025
0.012
0.013
Table 17. Booth 2 Average Chrome Concentrations at Specific Exhaust Face Heights.
Height
m(ft)
Test 1
(mg/m3)
Test 2
(mg/m3)
Test 3
(mg/m3)
Average
(mg/m3)
2.8 (9.3)
0.013
0.013
0.014
0.013
2.3 (7.6)
0.017
0.018
0.022
0.019
1.8 (5.9)
0.022
0.044
0.021
0.029
1.3 (4.2)
0.037
0.067
0.051
0.052
0.76 (2.5)
0.032
0.067
0.055
0.051
0.024 (0.8)
0.030
0.086
0.094
0.070
Table 18. Booth 3 Average Chrome Concentrations at Specific Exhaust Face Heights.
Height
m (ft)
Test 1
(mg/m3)
Test 2
(mg/m3)
Test 3
(mg/m3)
Average
(mg/m3)
2.8 (9.3)
0.0019
0.0090
0.0034
0.0047
2.3 (7.6)
0.011
0.039
0.025
0.025
1.8(5.9)
0.049
0.085
0.044
0.059
1.3 (4.2)
0.15
0.15
0.088
0.13
0.76 (2.5)
0.17
0.14
0.062
0.12
0.024 (0.8)
0.076
0.063
0.056
0.065
66
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Table 19. Booth 1 Average Organic Concentrations at Specific Exhaust Face Heights.
Height
m (ft)
Test 1
(mg/m3)
Test 2
(mg/m3)
Test 3
(mg/m3)
Average
(mg/m3)
4.4 (14.4)
210
190
180
190
3.9 (12.7)
240
290
240
260
3.3 (11.0)
310
360
290
320
2.8 (9.3)
360
370
260
330
2.3 (7.6)
400
440
340
390
1.8 (5.9)
400
470
340
400
1.3 (4.2)
450
350
300
370
0.76 (2.5)
360
370
300
340
0.024 (0.8)
200
150
170
170
Table 20. Booth 2 Average Organic Concentrations at Specific Exhaust Face Heights.
Height
m (ft)
Test 1
(mg/m3)
Test 2
(mg/m3)
Test 3
(mg/m3)
Average
(mg/m3)
2.8 (9.3)
74
44
87
68
2.3 (7.6)
87
64
120
90
1.8 (5.9)
99
100
160
120
1.3 (4.2)
170
120
170
150
0.76 (2.5)
130
120
170
140
0.024 (0.8)
150
160
230
180
Table 21. Booth 3 Average Organic Concentrations at Specific Exhaust Face Heights.
Height
m (ft)
Test 1
(mg/m3)
Test 2
(mg/m3)
Test 3
(mg/m3)
Average
(mg/m3)
2.8 (9.3)
13
18
15
15
2.3 (7.6)
23
31
27
27
1.8 (5.9)
43
67
62
57
1.3 (4.2)
89
170
160
140
0.76 (2.5)
68
120
130
110
0.024 (0.8)
51
180
150
130
67
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Metal Mass Profile
20
15
1 0
5
0
80
100,
60
40
20
0
Percent below height
Organic Mass Profile
20
15
10
5
0
80
100
60
20
40
0
Percent Below Height
Figure 12. Cumulative Distribution of Metal and Organic Constituents at Various Heights
Across the Exhaust Face for Booth 1, (to ensure conservative results, one outlying
data point was omitted from the average results obtained to derive the metals graph).
68
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Metal Mass Profile
12
1 0
8
6
4
2
0
0
20
40
60
80
100
Percent Below Height
Organic Mass Profile
12
10
8
6
4
2
0
60
100
80
20
40
0
Percent Below Height
Figure 13. Cumulative Distribution of Metal and Organic Constituents at Various Heights
Across the Exhaust Face for Booth 2.
69
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Metal Mass Profile
12
10
8
6
4
2
0
40
60
80
0
20
100
Percent Below Height
Organic Mass Profile
12
10
8
6
o>
4
2
0
80
100
60
40
20
0
Percent Below Height
Figure 14. Cumulative Distribution of Metal and Organic Constituents at Various Heights
Across the Exhaust Face for Booth 3.
70
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Table 22. Booth 1 Painter Vicinity Measurements in Single-Pass Mode.
Test 1
Test 2
Test 3
Average
Painter
Painter
Painter
Painter
Painter
Painter
Painter
Painter
Constituent Concentrations (mg/m1)
Trivalent chromium
0.065
0.028
0.098
0.012
0.058
0.009
0.074
0.016
Hexamethylene diisocyanate
0.035
0.018
0.0054
0.011
0.025
0.014
0.022
0.015
Methyl ethyl ketone
60
37
42
ND'
100
57
68
45
Ethyl acetate
0.25
0.33
0.24
ND
0.39
0.34
0.29
0.34
Methyl isobutyl ketone
130
58
83
ND
240
120
150
87
Toluene
140
71
86
ND
250
120
160
96
Butyl acetate
71
36
41
ND
80
48
64
42
Methyl isoamyl ketone
260
130
140
ND
160
100
190
120
Ethyl benzene
50
31
35
ND
73
44
53
38
Total xylenes
290
152
190
ND
490
250
320
200
Trimethyl benzene
12
6.7
8.5
ND
13
9.5
11
8.1
Hexyl acetate
15
7.9
10
ND
17
13
14
11
OSHA Factor outside respirator
3.3
1.7
1.7
1.72
3.8
2.0
2.9
1.8
Calculated painter OSHA Factor
(assigned protection factor of 10)
0.33
0.17
0.17
0.17
0.38
0.20
0.29
0.18
Calculated painter OSHA Factor
(assigned protection factor of 25)
0.13
0.068
0.068
0.068
0.15
0.08
0.12
0.072
1
2
ND = No data; sample lost due to field sampling error.
The OSHA Factor reported here was derived from the organics data collected for the other painter at the same time.
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Table 23. Booth 2 Painter Vicinity Measurements in Single-Pass Mode.
Test 1
Test 2
Test 3
Average
Painter
Painter
Painter
Painter
Painter
Painter
Painter
Painter
Constituent Concentrations (mg/m3)
Hexavalent chromium
0.0035
0.0042
0.0060
0.0046
0.0012
0.0019
0.0030
0.0040
Phosphoric acid
0.016
0.016
0.017
0.017
0.014
0.014
0.016
0.016
Hexamethylene diisocyanate
0.0012
0.0030
0.0013
0.0091
0.0011
0.0059
0.0010
0.0060
Methyl ethyl ketone
4.2
5.6
5.2
6.8
5.5
16
5.0
9.5
Ethyl acetate
0.63
0.23
0.16
0.16
0.30
0.53
0.31
0.25
n-Butanol
7.4
2.4
8.3
0.18
4.9
0.68
6.9
1.1
Methyl isobutyl ketone
1.5
13
3.1
11
1.7
3.5
2.1
9.2
Toluene
2.4
12
3.6
11
1.8
4.1
2.6
9.0
Butyl acetate
0.56
4.2
1.6
4.5
0.99
1.4
1.1
3.4
Methyl isoamyl ketone
0.15
0.15
0.16
0.16
0.13
0.13
0.15
0.15
Ethyl benzene
0.60
5.4
1.5
4.5
1.1
1.4
1.1
3.8
Total xylenes
3.1
27
8.1
23
6.3
7.0
5.8
19
Trimethyl benzene
1.4
1.6
1.9
1.6
1.6
0.44
1.6
1.2
Hexyl acetate
0.20
1.0
0.94
1.7
0.72
0.46
0.62
1.1
OSHA Factor outside respirator
3.6
4.5
5.8
5.0
1.3
2.2
3.6
3.9
Calculated painter OSHA Factor
0.14
0.18
0.23
0.20
0.052
0.088
0.14
0.16
(assigned protection factor of 25)
Note: This table assumes that hexavalent chrome comprises one-half of the chrome measured in the vicinity of the painter.
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Table 24. Booth 3 Painter Vicinity Measurements in Single-Pass Mode.
Test 1
Test 2
Test 3
Average
Painter
Painter
Painter
Painter
Constituent Concentrations
(mg/m3)
0.014
0.0039
0.010
0.009
Hexavalent chromium
0.014
0.015
0.015
0.015
Phosphoric acid
0.001
0.001
0.001
0.001
Hexamethylene diisocyanate
20
65
59
48
Methyl ethyl ketone
0.13
0.20
0.58
0.30
Ethyl acetate
3.4
4.6
4.1
4.0
n-Butanol
5.2
7.2
4.8
5.7
Methyl isobutyl ketone
7.5
9.9
5.8
7.7
Toluene
4.1
5.4
2.4
4.0
Butyl acetate
0.13
0.14
0.14
0.14
Methyl isoamyl ketone
2.3
3.2
2.1
2.5
Ethyl benzene
12
16.
11
13
Total xylenes
1.7
1.5
1.4
1.5
Trimethyl benzene
2.4
2.9
1.3
2.2
Hexyl acetate
OSHA Factor outside respirator
14
4.2
10
9.4
Calculated painter OSHA Factor
0.55
r 0.17
0.41
0.38
(assigned protection factor of 25)
Note: This table assumes that hexavalent chrome comprises one-half of the chrome
measured in the vicinity of the painter.
73
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Table 25. Booth 1 Painter Vicinity Measurements in Recirculation Mode.
Test 1
Test 2
Test 3
Average
Painter
Painter
Painter
Painter
Painter
Painter
Painter
Painter
Constituent Concentrations (mg/m3)
Trivalent chromium
0.006
0.035
0.037
0.013
0.0036
0.048
0.016
0.032
Hexamelhylene diisocyanate
0.026
0.013
0.0089
0.021
0.034
0.023
0.023
0.019
Methyl ethyl ketone
17
65
31
44
66
57
38
55
Ethyl acetate
0.22
0.24
0.23
0.23
0.34
0.26
0.26
0.24
Methyl isobutyl ketone
44
160 E
150E
190
220
210
140
190
Toluene
41
150E
140E
190
270
220
150
190
Butyl acetate
18
62 E
00
m
67
92
76
53
68
Methyl isoamyl ketone
2.0
23
3.3 E
8.2
9.7
12
5.0
14
Ethyl benzene
18
65 E
59 E
75
110
89
62
76
Total xylenes
94
340 E
310 E
410
600
480
340
410
Trimethyl benzene
3.7
13
11
13
20
15
12
14
Hexyl acetate
5.5
16
7.9
11
17
13
10
13
OSHA Factor outside respirator
1.3
2.4
2.0
2.8
4.0
3.3
2.4
2.8
Calculated painter OSHA Factor
(assigned protection factor of 10)
0.13
0.24
0.19
0.28
0.40
0.33
0.24
0.28
Calculated painter OSHA Factor
(assigned protection factor of 25)
0.052
0.096
0.076
0.112
0.16
0.13
0.096
0.112
E Value estimated from chromatograph results
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Table 26. Booth 2 Painter Vicinity Measurements in Recirculation Mode.
Test 1
Test 2
Test 3
Average
Painter
Painter
Painter
Painter
Painter
Painter
Painter
Painter
Constituent Concentrations
(mg/m3)
0.0012
0.0048
0.0024
0.011
0.0012
0.0014
0.0016
0.0057
Hexavalent chromium
0.012
0.012
0.014
0.015
0.014
0.014
0.013
0.014
Phosphoric acid
0.0010
0.0011
0.0011
0.0061
0.0011
0.0046
0.011
0.0039
Hexarhethylene diisocyanate
6.6
36
4.1
13
4.1
29
4.9
26
Methyl ethyl ketone
0.11
0.73
0.13
0.14
0.21
0.16
0.15
0.34
Ethyl acetate
7.6
3.8
7.9
2.2
6.7
3.2
7.4
3.1
n-Butanol
2.7
21
3.2
8.3
2.8
20
2.9
16
Methyl isobutyl ketone
4.5
32
6.3
11
3.7
26
4.8
23
Toluene
2.5
16
2.5
5.1
8.0
45
4.3
22
Butyl acetate
0.11
0.14
0.13
0.14
0.13
0.13
0.12
0.14
Methyl isoamyl ketone
1.5
9.4
1.8
3.6
0.97
5.2
1.4
6.1
Ethyl benzene
8.1
52
9.9
18
6.8
33
8.3
34
Total xylenes
2.6
6.1
2.9
2.0
2.2
4.4
2.6
4.2
Trimethyl benzene
2.5
9.0
2.1
2.5
1.9
6.2
2.2
5.9
Hexyl acetate
OSHA Factor outside respirator
1.4
5.2
2.6
11
1.5
1.8
1.9
6.1
Calculated painter OSHA Factor
0.056
0.21
0.10
0.44
0.060
0.072
0.076
0.24
(assigned protection factor of 25)
Note: This table assumes that hexavalent chrome comprises one-half of the chrome measured in the vicinity of the painter.
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Table 27. Booth 3 Painter Vicinity Measurements in Recirculation Mode.
Test 1
Test 2
Test 3
Average
Painter
Painter
Painter
Painter
Constituent Concentrations
(mg/m3)
0.014
0.0019
0.0021
0.0060
Hexavalent chromium
0.013
0.013
0.012
0.013
Phosphoric acid
0.00085
0.00085
0.00085
0.00085
Hexamethylene diisocyanate
ND1
41
110
76
Methyl ethyl ketone
ND
0.16
0.31
0.24
Ethyl acetate
ND
3.9
5.8
4.9
n-Butanol
ND
5.8
4.3
5.1
Methyl isobutyl ketone
ND
11
8.7
9.9
Toluene
ND
3.1
2.6
2.9
Butyl acetate
ND
0.13
0.13
0.13
Methyl isoamyl ketone
ND
2.8
2.0
2.4
Ethyl benzene
ND
14
10
12
Total xylenes
ND
1.8
1.4
1.6
Trimethyl benzene
ND
1.7
1.0
1.4
Hexyl acetate
Resulting OSHA Factor
14
2.1
2.4
6.1
Calculated Painter OSHA Factor
0.54
0.084
0.096
0.24
(assigned protection factor of 25)
'ND = No data; sample lost due to field sampling error. The OSHA Factor reported
here was derived only from the non-organic painter vicinity sampling data. It is
believed that the organic concentration in the vicinity of the painter in Booth 2 is small,
thus lack of organic data for this result should not impact the results repored herein.
Note: This table assumes that hexavalent chrome comprises one-half of the chrome
measured in the vicinity of the painter.
76
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6.3.2 Implications of Painter Vicinity Sampling Results.
From the results reported in Tables 22 through 27, it is immediately apparent that
recirculation does not have a discernable impact on the painter vicinity concentrations. This
premise was confirmed via statistical analysis to determine the data precision for each test event.
The precision (or variability) of the measurement provides a means of discerning and
quantifying recirculation impacts.
The results of this precision analysis are summarized in Table 28; note that the term
"variability range" is defined as the interval occurring within one standard deviation of the
average value. For Booths 1 and 3, the OSHA Factor variability range under single pass (non-
recirculating) conditions is virtually the same as the OSHA Factor range occurring under
recirculating conditions.
The Booth 2 results under the recirculation condition indicate slightly increased average
and range values, however this can be traced to the OSHA Factor value of 11 measured in the
vicinity of Painter 2 during Test 2. This value is significantly higher than any other
measurements collected in Booth 2. No additional data exist to explain this measurement such
as observation, however, if we consider this individual result to be a data outlier, the Booth 2
OSHA Factor under recirculating conditions is much lower than under single-pass operation. It
is possible that the painter inadvertently applied paint obliquely to the sample cassette used to
derive this particular result.
Because the differences measured for the single-pass and recirculation conditions fall
within the measurement variability range, it is reasonable to conclude that recirculation has little
or no measurable impact on the constituent concentrations in the vicinity of the painter. The
data further indicates that the "cloud effect" is the principal contributor to the painter exposure
level. This confirms similar findings reported previously at other painting facilities.19
Several operational issues immediately become apparent in reviewing the results
presented in Tables 22 through 27. First, it appears that organic and inorganic constituent
concentrations in the vicinity of the Booth 1 painters under recirculating and non-recirculating
conditions are much higher than the concentrations found in the vicinity of the painters in
Booths 2 and 3. This difference stems from the fact that Booth 1 is a vehicle booth in which the
painters move around large equipment (armored personnel vehicles [APVs], Humvees, etc.) and
workpieces that are painted. Under these conditions, the painters frequently paint either against
or across the ventilation airflow, thus overspray particulate and solvent vapors often surround
them in a heavy cloud. Furthermore, the painters in Booth 1 often paint in the confined space
underneath the vehicles, or are located downwind of painted vehicle sections from which
organic vapors are released as the coating dries (e.g. flash-off). It is likely that these factors
contribute heavily to the organic concentrations in the vicinity of the painter, and therefore
contribute to the OSHA Factor results reported in Tables 22 and 25. Conversely, the painters in
Booths 2 and 3 tend to remain upwind of the target workpiece, and therefore do not become so
surrounded by the overspray cloud or paint drying fumes.
77
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Table 28. Precision Analysis of Painter Vicinity OSHA Factor Measurements.
^ Condition
Test
Booth 1
Painter 1 Painter 2
Booth 2
Painter 1 Painter 2
Booth 3
Painter
Single-Pass
Mode
Test 1
3.3
1.7
3.6
4.5
13
Test 2
1.7
1.71
5.8
5.0
4.2
Test 3
3.8
2.0
1.3
2.2
10
Average (painter 1&2)
2.4
3.7
9.1
Standard Deviation
0.86
1.6
3.7
Variability Range2
1.5-3.2
2.2 - 5.3
5.4-12.7
Recirculation
Mode
Test 1
1.3
2.4
1.4
5.2
133
Test 2
1.9
2.8
2.6
11
2.1
Test 3
3.9
3.3
1.5
1.8
2.4
Average (painter 1&2)
2.6
3.9
5.8
Standard Deviation
0.86
3.4
5.1
Variability Range2
1.7-3.5
0.5-7.3
0.76-10.9
Booth 2 Average Without Outlier
2.5
Booth 2 Standard Deviation Without
Outlier
1.4
Booth 2 Variability Range
Without Outlier
1.1-3.9
1 The OSHA Factor was derived from organics data collected for the other painter - See Table 22.
2 Range is defined as the interval that is within one standard deviation of the average value.
3 The OSHA Factor reported here was derived only from the non-organic painter vicinity sampling
data. It is believed that the organic concentration in the vicinity of the painter in Booth 2 is small,
thus lack of organic data for this result should not impact the results reported herein - See Table 27.
It is not intuitively obvious why the Booth 1 OSHA Factor is generally lower than the
OSHA Factors determined for Booths 2 and 3, especially because the painter vicinity
concentrations are much higher. As indicated in Equation 1, the OSHA Factor is derived from
two parameters; the concentration of a particular constituent as well as the specific PEL for that
constituent. The OSHA Factor results reported for Booths 2 and 3 are somewhat higher than the
results reported for Booth 1, which indicates the presence of one or more compounds having
relatively low PELs which are in the coatings used in Booths 2 and 3 , and not present in Booth
1. As indicated in Section 3, Booth 1 is used for topcoat applications only, thus only the
trivalent form of chromium is present in Booth 1. However, a wash primer material containing
hexavalent chromium is applied in Booths 2 and 3, and the PEL for hexavalent chrome is much
lower than the PEL for any other compound present, thus it has a major impact on the OSHA
Factors indicated for Booths 2 and 3.
78
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It is easily surmised from these results that the impact of recirculation on the quality of
the ventilation air surrounding the paint booth operators is relatively imperceptible. The fact
that the total coating usage rates (Table 15) for each booth during the recirculation tests are
consistently higher than the usage rates recorded during the single-pass tests further substantiates
this conclusion. Finally it should be noted that the OSHA PELs employed to derive the painter
vicinity OSHA Factors reported in Tables 22 through 27 are 8 hour TWAs, thus the OSHA
Factor results assume that the paint booth operators apply paint in the booths for 8 hours per day.
Of course, typical painting intervals (the hours per day that paint is actually sprayed) do not
exceed 4-5 hours a day (if thai much). Therefore, actual painter vicinity OSHA Factors are at
least 25% lower than those reported in Tables 22 through 27.
6.4 COMPARISON OF FTIR RESULTS TO NIOSH 1300 SPECIATED ORGANIC
DATA AND FID RESULTS
The results of the NIOSH 1300 speciated organic concentration measurements and the
EPA Method 25A data collected in the recirculation ducts during the Technology Demonstration
Study were compared against preliminary FTIR data to enhance the FTIR spectral analysis
software, and evaluate the results of the FTIR measurements.1014 The results of this comparison
for Booths 1,2, and 3 are indicated in Tables 29, 30, and 31, respectively. The following
procedures were employed to perform this analysis:
1) For each test, the NIOSH 1300 speciated data collected in each of the two
recirculation ducts were reconciled with the volumetric flow rates measured in these
ducts and then averaged to derive a single, representative recirculation stream
concentration value for each constituent.
2) For each test, the instantaneous FID results measured (via EPA Method 25A) in each
recirculation duct were averaged to derive a single concentration value that
represents the organic carbon concentration measured in each exhaust duct. The
calculated concentration value was then reconciled to obtain a single, representative
recirculation duct organic concentration value for each test.
3) During each test, a continuous sample gas stream was extracted from each
recirculation duct; these sample streams were combined and then passed through the
FTIR sample cell. The FTIR operated continuously throughout each test, thus the
results obtained for each constituent were averaged over the sampling period to
obtain a single, representative recirculation stream concentration value from the
FTIR results.
4) The results of Steps 1 through 3 were compared to assess the overall performance of
the FTIR system.
79
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Table 29. FTIR - NIOSH 1300 Comparison Summary for Booth 1 Recirculation Duct Samples.
Organics 3 (mg/m3)
Organics 4 (mg/m3)
Organics 6 (mg/m3)
Compound
FTIR
NIOSH
FTIR
NIOSH
FTIR
NIOSH
Butyl + Hexyl acetates
57
26
78
21
66
14
MEK
16
19
17
16
9
6
MIAK + MIBK
95
39
135
42
132
24
Ethyl benzene
40
20
67
17
53
14
Xylenes
115
105
173
87
186
71
Toluene
50
44
72
36
74
28
Total Carbon
613
427
902
368
872
271
Total Carbon from
FID measurement
399
434
438
The FTIR spectral analysis software installed on the MCLB paint booths was developed
specifically for this application. It is evident from the data presented in Tables 29 through 31
that, in instances where there is disagreement between the FTIR results and the NIOSH 1300
results, the FTIR consistently yields higher concentrations. This in fact increases the safety
factor inherent in the monitoring system, because the FTIR has a tendency to over predict the
constituent concentrations. Thus, if the FTIR system detects concentrations in the recirculation
duct that exceed the established setpoint, it is likely that the actual concentrations in the
recirculation duct are somewhat lower.
In actuality, it is anticipated that the concentrations measured by the FTIR systems that
were installed at MCLB actually provide more realistic and representative data than it appears in
Tables 29 through 31. This conclusion is drawn from a number of factors, including:
• The FTIR spectral data collected during the Technology Demonstration Study were
taken at a one-half wave number (0.5 cm"1) resolution. However, to reduce
processing time and increase the signal to noise ratio, the FTIR systems installed on
the MCLB paint booths are set at one wavenumber (1 cm"1) resolution, and 0.5 cm"1
analysis software was developed accordingly. In analyzing the 0.5 cm"1 spectral
results reported in Tables 29 through 31, the data were first deresolved prior to
analysis with the 1 cm"1 resolution software. This reduces the spectral match in the
analysis module, and therefore had an impact on the results presented in Tables 29
through 31.
80
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Table 30. FTIR - NIOSH 1300 Comparison Summary for Booth 2 Recirculation Duct Samples
00
Organics 1
(mg/nr1)
Organics 2
(mg/m3)
Organics 4
(mg/m3)
Organics 6
(mg/m3)
Compound
FTIR
NIOSH
FTIR
NIOSH
FTIR
NIOSH
FTIR
NIOSH
Butyl + Hexyl
acetates
55
16
30
8
90
35
88
23
n-Butyl alcohol
12
3
16
5
10
10
37
13
MEK
45
39
32
8
22
14
158
9
MIAK + MIBK
31
12
17
8
45
11
15
13
Ethyl benzene
2
3
0
4
8
3
2
7
Xylenes
63
17
48
20
56
23
91
34
Toluene
28
12
21
12
30
16
52
24
Total Carbon
368
153
258
104
405
170
664
214
Total Carbon from
FID measurement
137
110
183
212
-------
Table 31. FTIR - NIOSH 1300 Comparison Summary for Booth 3 Recirculation Duct Samples.
Organics 1
(mg/m3)
Organics 2
(mg/m3)
Organics 3
(mg/m3)
Organics 4
(mg/m3)
Organics 5
(mg/m3)
Compound
FTIR
NIOSH
FTIR
NIOSH
FTIR
NIOSH
FTIR
NIOSH
FTIR
NIOSH
Butyl + Hexyl
acetates
9
3
13
2
12
1
8
2
4
2
n-Butyl alcohol
2
1
14
2
11
1
1
1
6
1
MEK
0
2
14
2
33
3
0
2
35
2
MIAK + MIBK
41
1
16
1
0
1
15
1
2
2
Ethyl benzene
0
0
0
1
0
1
0
0
0
1
Xylenes
19
1
21
3
19
4
11
2
15
6
Toluene
7
1
11
3
29
6
7
4
13
7
Total Carbon
127
14
137
21
164
28
67
18
114
41
Total Carbon from
FID measurement
15
38
45
39
54
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• In the FTIR sampling portion of the Technology Demonstration Study, the air sample
collected during background spectra sample runs were probably not given the level of
conditioning and handling that is required to obtain precise results. This is because
the FTIR sampling system was not set up in the final configuration, thus "field test"
conditions occurred. Proper conditioning of background sample air is important
because moisture and residual organics will impact the analytical results. An
improved background system was developed for the FTIRs installed at MCLB.
The FTIR systems installed at MCLB were programed to perform the OSHA Summation
Rule calculation (Equation 1 in Section 2) on a continuous basis for each set of speciated
organic data that are collected. The TWA values programmed into the FTIR software to perform
this calculation are summarized in Table 32. Most of the TWA values are OSHA 8-hour PELs.
However, because the FTIR sample stream is extracted upstream of where the fresh make-up air
is brought into each booth, and because the FTIR operates on a continuous basis (and therefore
provides virtually instantaneous notification of excessive recirculation duct concentrations), it
was considered reasonable to program the FTIR with ACGIH 15 minute STEL values for select
compounds such as MEK. As indicated from an inspection of Tables 29 through 31, all of the
organic concentration results are well below the established OSHA levels.
Table 32. TWA Levels Programmed into the FTIR OSHA Additive Rule Calculation.
Compound
TWA Setpoint
TWA Source
ppm
mg/m3
Ethyl benzene
100
435
OSHA PEL
IPA
400
980
OSHA PEL
MEK (2-butanone)
300
590
ACGIH STEL
MIAK (5 methyl-2-hexanone)
100
475
OSHA PEL
MIBK (hexone)
100
410
OSHA PEL
PGMEA
100
Note 1
Toluene
200
766
OSHA PEL
Butyl acetate
150
710
OSHA PEL
Hexyl acetate
50
300
OSHA PEL
Xylenes
100
435
OSHA PEL
n-Butanol
100
300
OSHA PEL
No value specified by OSHA, ACGIH, or NIOSH. Thus, the 100 ppm OSHA PEL
for ethylene glycol monoethyl ether acetate (EGEEA) and propylene glycol
monomethyl ether (PGME) was substituted.
83
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Since completing the Technology Demonstration Study in December, 1995, the FTIR
systems installed at MCLB have found multiple applications as ventilation system evaluation
and diagnostic tools, in addition to the safety monitoring application originally envisioned. As a
result of these system diagnostic/evaluation efforts, several interesting operating characteristics
were identified,as follows:
• The use of new coatings was detected through these FTIR system diagnostic
exercises. These coatings were identified because the FTIR provides speciated
concentration data, thus anomalies with respect to solvent mixtures or unanticipated
results are noted from the FTIR data. The potential impact of these coating
reformulations is being assessed.
• Significant variability in the technical skill and paint application habits of individual
paint booth operators was noted when the Booth 2 FTIR repeatedly measured high
concentration excursions that triggered the ventilation system to convert to single
pass operation under seemingly "typical" painting circumstances. Upon inspection, it
was found that the FTIR system correctly responded to excursions created by
ineffective painter habits. It was further noted that the individual operating in Booth
2 when these excursions occurred tended to use significantly more coating material
and solvents than most painters that typically operate in Booth 2. As a result of these
observations, Barstow MCLB is contemplating the need for increased painter training
with respect to coating application and housekeeping procedures. The need for
painter training does not in any way reflect on the inherently safe recirculation
system; rather the training will serve to avoid nuisance interruptions that are the
result of easily preventable events generated by inefficient painter habits.
• To minimize migration of hazardous constituents from the high concentration zones
of the booth into the recirculation stream, it is necessary to adequately seal the filter
elements located at the partition level.
84
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SECTION 7
ECONOMIC BENEFITS OF RECIRCULATION AND OTHER
FLOW REDUCTION STRATEGIES
As indicated in Section 2, the cost to install and operate a typical VOC emission control
system is directly related to the volume flow rate processed by the device, thus reducing the
process exhaust flow rate will also reduce system costs. Moreover, VOC emission control
systems typically achieve a destruction efficiency of 95% or better, irrespective of the volume
flow rate that is processed. The key advantage of recirculation and the other ventilation system
enhancements installed on the MCLB paint booths is in achieving the flow reduction necessary
to decrease APCS installation/operating costs without sacrificing system performance in terms
of destruction efficiency and pollution prevention. However, it is recognized that the economic
advantages inherent in these flow reduction strategies are realized only if the ventilation system
design and installation costs are significantly offset by reductions in the installation and
operating costs associated with the VOC emission control system. This section summarizes the
results of a detailed economic analysis which demonstrates the economic benefits of
recirculation and the other flow reduction strategies implemented at the Barstow MCLB facility.
The three key parameters considered for this economic analysis are as follows:
• System exhaust flow rates .
• VOC emission control system configurations.
• Paint booth retrofit and VOC emission control system installation and operating
costs.
7.1 EXHAUST FLOW RATES
The process exhaust flow rate is a key parameter because it provides the basis for
establishing the cost savings accrued from recirculation and the other ventilation system
modifications discussed in Section 5. For this analysis, three different flow rates are considered:
Initial Configuration of Booths - The cost of controlling VOC emissions from the booths
in their initial single pass configuration provides the baseline for this analysis. As
indicated in Section 3, the initial exhaust flow rate was 4,064 m3/min (143,500 cfin).
Final Configuration of Booths - The final exhaust flow rate achieved after booth
modifications were complete is 1,176 m3/m (41,450 cfm). This flow reduction is
attributed to several factors, including recirculation/flow partitioning, VFD fans, and
interlocking operations such that Booth 1 may be operated any time, and Booths 2 and 3
operate sequentially. The 1,176 m3/min flow rate (41,450 cfm) is the combined exhaust
85
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from Booth 1 (572 m3/min [20,120 cfm] and Booth 2 (604 m3/min [21,330 cfm]).
Initial Configuration of Booths 1 and 2 - In the final configuration, the maximum
exhaust flow rate occurs when Booths 1 and 2 are operated simultaneously. It is
therefore appropriate to perform an emission control cost comparison for Booths 1 and 2
in their original configuration (at 3,285 m3/min [116,000 cfm]) and in their final
configuration (1,174 m3/min [41,450 cfm]).
The results of the economic analyses summarized in tabular form below were developed
based on these exhaust flow rate parameters.
7.2 VOC EMISSION CONTROL SYSTEMS
There are many different types of VOC emission control systems that may be employed
to control emissions from military paint spray booths. The fact that the installation and
operating costs of these systems vary significantly must also be taken into consideration to
develop an accurate and representative economic comparison. Two different VOC emission
control technologies are included in the economic analysis to give a spectrum of viable emission
control options and costs.
Regenerative Thermal Oxidizer (RTO): This systems achieves a very high thermal efficiency
(up to 95%) compared to standard thermal oxidizer systems. This significantly reduces the fuel
demand and the corresponding operating costs.
Rotor Concentrator/Recuperative Oxidizer frotor/recup): This system employs a two step flow
reduction process in which an adsorption rotor (zeolyte, carbon fiber, or other material) collects
and concentrates the solvent vapor. The collected organics are continuously desorbed from the
rotor and vented to a recuperative oxidizer. The rotor concentrator typically achieves a 10:1
volume flow reduction, which reduces both the size and the fuel demand of the recuperative
oxidizer.
7.3 PAINT BOOTH RETROFIT AND EMISSION CONTROL COST PARAMETERS
Although there are many equipment vendors that manufacture and install both RTOs and
rotor/recup systems, it was not necessary or feasible to solicit cost estimates from each
manufacturer and develop aggregate cost projections for the three flow rate scenarios considered
in this economic evaluation (see Section 7.1). Moreover, the objective of this economic analysis
is to demonstrate that recirculation/flow partitioning and the other ventilation system
modifications implemented on the MCLB paint booths significantly reduce VOC emission
controls costs. To achieve this objective, it is necessary only to present control cost data that
reasonably represent the spectrum of candidate emission control options. To develop the
economic analysis results, representative system installation and operating cost data were
obtained from the following sources:
86
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OAOPS Control Cost Manual: The Control Cost Manual was developed by EPA's Office of Air
Quality Planning and Standards (OAQPS) to provide facilities that face air pollution control
requirements with guidance and background information regarding various emission control
options.20 Data pertaining to RTO system installation and operating costs were obtained from
this manual and employed in the cost evaluation. In addition to RTO system costs, the OAQPS
Control Cost Manual was also used to estimate costs for site preparation and other logistics such
as foundation construction, utilities, startup, etc. The RTO system capital cost data provided in
the manual are in 1989 dollars, thus supplemental data pertaining to escalation indexes (also
provided by OAQPS) were employed to convert the capital cost data to 1995 dollars.
Paint Booth Retrofit Contractor - Paint booth system retrofit design, installation, and operating
cost estimates were supplied by Acurex Environmental Corporation. Acurex Environmental was
the prime contractor responsible for planning and implementing all booth retrofit activities, and
is therefore capable of providing accurate and representative estimates for system retrofit costs.
VOC Emission Control Vendor Cost Quotes - Two equipment vendors were contacted and
provided system capital, installation, and operating cost data for the three flow rate scenarios
considered in this evaluation. One provided supplemental data pertaining to RTO system
economics, and the second provided cost data pertaining to rotor/recup systems.
7.4 COST ANALYSIS RESULTS
An Equivalent Uniform Annual Cash Flow (EUAC) analysis was performed in
accordance with cost analysis procedures defined in Chapter 2 of the OAQPS Control Cost
Manual.20 The analysis assumes a twelve year life for the control systems and provides an
average annualized cost for the system. The recirculation/patrition modification to the spray
booths were shown to produce an immediate cost savings benefit.
The installation and operating EUAC cost analysis results for the three VOC emission
control systems considered were completed for three flow scenarioes: 41,450 cfm, 116,000 cfm,
and 143,500 cfm, Tables 33, 34, and 35, respectively. Supplemental information employed to
derive these cost estimates are summarized in footnotes to each table. The results of the EUAC
comparison are summarized in Table 36, and clearly indicates the significant economic benefit
of installing the recirculation/partition flow system and making the other system adjustments
described in Section 5.
The cost comparison evaluation was performed in accordance with the EUAC procedures
and assumes a 12 year equipment life, and an 8% interest rate. As shown in the summary Table
36 the lower system capital and installation costs incurred for the integrated recirculation/VOC
emission control system result in immediate cost benefits. For example, the EUAC analysis
result for installing and operating a rotor/recup system to control emissions from Booths 1 and 2
without recirculation (i.e., a flow rate of 116,000 cfm, and paint booth retrofit costs of $0) is
87
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$476,260 annualized cost over the twelve year life of the system. However, the result for
operating the rotor/recup system to control emissions from Booths 1 and 2 modified with
recirculation (i.e., a flow rate of41,450 cfm and booth modification costs of $350,000) is
$308,540 annualized cost over the twelve year period. Over the twelve year period, a
$2,019,120 cost savings is realized due to the recirculation/partition booth modification. This
represents a 35% reduction in annualized EUAC costs, as well as a 25% reduction in
capital/installation costs and 53% reduction in system operating costs.
88
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Table 33. Emission Control System Installation/Operating Costs at 1,176 m3/min Ml.450 cfml
INITIAL. CAPITAL A.NC INSTALLATION COSTS -41,450 cfrn, Booths 1 & 2 oparatod after retrofit (Booth 3 retrofit costs notincludsd)
Purr-hased APC 5 Equipment Cost
Control equipment capital cost
Auxiliary equipment
Sa.es tax (5%) (1) '
Freight
Tctil APCS purchase equipment cos
RTQ - OAOPS data (2)
5310.414 (1)
sso.ooo (3)
543.021
534.417 (4%) (1)
5337,252
RTO Vendor data
5503.425 (5)
550.000 (3)
527,671
534,417 (OAQPS Value)
5815,513
Rotor/Recup Vendor data
saoo.ooo (5)
550.000 (3)
542.500
534.000 (5)
5925,500
Direct APCS Installation Costs
Foundation & Supports (4%) (1)
537.514
(4%) (1)
537.514
(OAQPS Value)
541,400 (5)
Handling S Erection (5%) (1)
546,393
(5%) (1)
526.500
(51
551.800 (5)
Electrical A Piping (5"A) (1)
546.893
(5%) (1)
546.893
(OAQPS Value)
551.800 (5)
Insulation (.05%) (1)
54.689
(0.05%) (1)
54.839
(OAQPS Value)
S5.200 (5)
Totz.1 Oirect APCS Installation Cost
5135.989
5115.596
5150.200
Indirect APCS Installation Costs
Engineering
537,514
(4%) (1)
. 513.423
(5)
5225,000 (5)
Construcdon/fiiild expenses
518.757
(2%) (1)
(included)
(included)
Contractors fees
546.893
(5%) (1)
(included)
(incijded)
Sti>rt-up
518.757
(2%) (1)
513.757
(OAQPS Value)
520.700 (5)
Performamje test
59.379
(1%) (1)
59,379
(OAQPS Value)
510,400 (5)
Contingencies
528.136
(3%) (1)
520,950
(5)
531,000 (5)
Total indirect APCS installation cost
5159.435
SS2.514
5237.100
Psirt Sccth retrofit cast (4):
S350.000
5350,000
5350,000
TOTAL INSTALHTHD COST:
51.533.275
51,143,623
S1.713.300
(1) Unless otherwise specified, the faeprs were taken from the OAQPS Manual
(2) OAQPS Manual RTO capital cast assumptions include:
- Costs reported are 1st quarter 1989 dollars: conversion data from OAQPS manual supplements
-"Formula: 5 » (2.204X 10E5) + 11.57Q
- Rasulrs: 1983 5 1995 S
5699.977 5310.414
(3) Auxiliary equpment is monitoring system
(-} Paint tooth installation data from Acy.-ex Environmental Oesign Group
(5) Mar.ufticturers' estimated cost
OPEftATiNG CO:3TS (1)
APCS
Eieicsicty (4)
Natural gas (5)
Msintenant» (G)
Miscellaneous
Pair: Sooths
Maintenance l£bor (B)(
£ii«ric:ty (4) (£1)
-BTv--.Q&? P S-daia, (21101_
136
3.37
4
ss.ono
8
3S.4
kW(3)
MStu/hr
hri\vk
S/yr
ftr/wk
kW
TOTAL ANNUAL OPERATING COST:
5/hr
58.15
515.88
520.00
S20.00
S2.36
5/yr
524.442
555,700
54.000
•55,000
sa.ooo
S7.092
S103.234
RTO Vendor m
. BatariBssup.ysrrisr .fqiuO)
113 IcW (8)
Sttir S/yr
55.78 520,340
3.97 MBtu/hr (8 S15.88 554,005
4 hr/wk
55.000 S/yr
8 hr/wk
39.4 kW
520.00
54,000
55,000
520.00 58,000
S2.36 57,092
598,437
65 kW(8)
2.C4 MBtu/hr (8
4 hr/wk
57,500 S/yr (8)
5/hr
S4
S/yr
SI t,700
S3 S42.840
520 S4.0C0
57,500
50
8 hr/wk
39.4 kW
520.00
52.35
5-5,000
57,032
S31,132
(1) Booths operate 10 hours/day, S days/week, 50 weeks/year
(2) RTO Vender assumptions for standard and startup operations:
RTO operates at 95i<> thermal efficiency 10 hrs/day
RTO operates additional 4S min/day @ full fire (S.7 MBTu/hr) 5 days per week
RTO operates additional 1 hr/day @ full fire (6.7 MSTu/hr) 1 day per week
[last two items ;idds anual n g. cast factor of (3/M8tu"5.7M Stu/hr)"S0"[(5"4S/S0) + 1]
OAQPS Manual Assumptions for standard and start-up operations:
RTO operates at 95% thermal efficiency 10 hrs/day
RTC operates additional 1.5 hour per day © full fire (6.7 MSTu/hr)
Additional OAQPS Manual assumptions:
14 inch pressure drop through system
fan/motor efficiency is 50% (e)
electricity calculated from the formula: 1.l4E-4*Q*dp/e
Electricity is S0.06/VWhr
The following assumptions apply to all control systems data sets:
Matural gas is 54/Mbtu
Oxidizer operated at 1650?
Heat capacity of air is G.255 atulbr, density is 0.0739 Ih/srf
l.itake air is at an avertige temperature of 70F
Tners- is no fuel value in exnaust gas
Mainte-iama labor is 520/hr
Maintenance items such as filter replacement are the same for recirculating & non-recirculating booths and are therefore not included
Manufacturers' estimate
Paint booth operating data from Acurex environmental energy audit/estimate: Sooths 14 2 operated simultaneously in final configuration
(3)
w
(5)
(>5)
(7)
(3)
(S)
89
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Table 34. Emission Control System Installation/Operating Costs at 3,280 m7min CI 16.000
IKfTLM. CAPITAL AND INSTALLATION COSTS -118,000 efm. Booths 1 & 2 only In th«(r original configuration
Pu.Tihased APCS Equipment Cost
Control ecjipr.ient capital
AuaHiary equipment
S ales tax (5%) (1)
Ffeight
Total APCS capital coat
Otr-jcs APCS Installation Casts
Foundation & Supports
Handling S Emcion
E'ectrical .1 Piping
Insulation (.05%) (1)
Total Direct APCS Installation Cost
Indirect APCS Installation Casts
Engineering
Construction/field expenses
Contractor fees
S'jrt-up
Performance test
Contingencies
Total indireij APCS installation cost
Pa-nt Sooth retrofit cost (4):
TOT/5-LINSTALLATED COST:
RTO - OAQPS data (2)
S1.3Q9.Q45 (1)
350.000 (3)
S32.9S2
374,362 (4%)(1)
S2.02S.359
531,054 (4%}(1)
5101.318 (5%)(1)
5101.313 (5%)(1)
510,132 (0.05%)(1)
3293.322
531.054 (4%) (1)
540,527 (2%) (1)
5101,318 (5%) (1)
540.527 (2%)(1)
520.254 (1%)(1)
560,791 (3%) (1)
5344,431
50
52.534.So2
RTO Vendor data
S1.213.200 (5)
$50,000 (3)
563.160
574,362 (OAQPS Value)
J1.400.722
$31,054 (OAQPS Value)
560.200 (5)
5101.318 (OAQPS Value)
310.132 (OAQPS Value)
S252.704
526,735 (5)
(included)
(included)
540.527 (OAQPS Value)
520,264 (OAQPS Value)
541.300 (5)
5128.876
SO
51.782.302
Rotor/Recap Vendor data
51.320.000
550.000 (3)
563.500
554.800
51.493.300
559.732
574.865
574.665
57.467
5216.529
5430.000 (5)
(included)
(induded)
529,866
514,933
544.799
1569.598
50
52.279.427
(1) Unles:; otherwise specified, the facers were taken from the OAQPS Manual
(2) OAQPS Manual RTO capital cost-assumptions include:
• Costs reported are 1st quarter 1939 dollars; conversion data from OAQPS manual supplements
- Fcmrjla: ¦ 5 - (2.204 X 10E5) » 11.57Q
- Pesults: 1939 S 1995 5
S1.5S2.520 S1.309.045
(5) Auxiliary equipment is monitoring system
(4.) Paint Scotn installation data from Acurex Environmental Cesign Group
(5) Manufacturers' estimate for system cost.
OPEflATING COSTS (1)
APCS
EecrtcSy (4)
Natural gas (5)
Maintenance (6)
Miscellaneous
Paint Sooths
Maintenance labor (6)(7)
E«sricr/(4) (9)
970-OAQPS data (2) m
330 JtW (3)
10.4 MSturhr
4 hrfwk
510.000 5/yr
3 hnSvfc
37.9 k'.V
SJhr S/yr
$22.80 563,403
541.45 5154,438
520.00 54.000
S10.000
520.00 58.000
55.87 S 17,622
RTO Vendor ffl..
S/hr S/yr
282 kW(B) S16.92 S50.7S0
10.50 MBtu/hr (3 $42.01 $145,138
4 hn\wk S20 S4.000
BatortRecua Vender fWIOI
S/hr
16a kW(8) S10
4.95 MStu/hr (8 520
$10,000 S/yr
3 hr/wfc
97.9 kW
4 ItrMk
S10.000 510,000 S/yr
TOTAL ANNUAL OPERATING COST:
S2S2.513
520 53,000
SS 517,622
5235,520
3 hrAvk
97.9 m
$20
s:o
56
S/yr
S30.225
$103,950
54,000
510.300
«.:oo
SI 7.522
$173,737
(1) Booths operate 10 hours/day. S days/week. 50 weeks/year
(I) RTO Assumptions for standard and startup operations:
RTO operates at 95% thermal efficiency 10 hrs/day
RTO operates addiional 45 min/day (O full fire (20.1 MBtu/hr) S days per week
RTO operates additional 1 tiour/day@ fufl fire (20.1 MBTu/hr) 1day per week
(last two items adds anua! n.g. cost factor of (5/Stu"20.1 Stu/hr)"S0/O.05"t(5"45/6Q) * 1]
OAQPS Assumptions for sta/idam and startup conditions
RTO operates at 95% thermal efficiency 10 hrs/day
RTO operates additional 1.5 hr per day @ full fire (20.1 M8tu/hr)
(") Additional OAQPS Manual assumptions:
14 inch pressure drop through system
fan/motor efficiency is £0% (e)
electricity calculated from the formula: 1.14E-4*Q*dp/e
leerc*y j 50.06/kWhr
(J) The fellow ng assumptions apply to aJ control systems data sets:
Natural gas is J4/Mbtu
Oxidizer operated at 1650F
Hear capacity of air is 0.255 3tui1SF: density is 0.0739 IS/stf
Intake air is at an average temperature of 70F
Them is no fuel value in exhaust gas
Maintenance labor is S20/hr
Mamtnnance items such as filer replacement are the same for recirculating & non-recirculating booths and are therefore not included
Manulacturers' estimate
Paint Ixaotn operating data from Acurex Environmental energy audit/estimate: Sooths 14 2 operatod simultaneously in original configuration
(4)
(«)
0)
(£)
(S)
(10) Rotor concentrator achieves a 10:1 volume reduction
90
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Table 35. Emission Control System Installation/Operating Costs at 4,064 m3/min (143,500 cixn).
INITIAL CAPITAL AN ~ INSTALLATION COSTS • 1X3,500 cfm, Booths 1, 2, and 3 operated simultaneously In their ericir.ii configuration
¦ Pu"Chased APCS Equipment Cast
Control equipment capital
AuxSiar/ equipment
Sales tax (5%) (1).
F.-eight
Total APCS capital coat
Ciric: APCS Installation Costs
F-Jundation & Supports (4%) (1)
Handling 2 EmeSon (S%) (1)
E'ecaical .1 Piping (5%) (1)
Insulation
Total Direct APCS Installation Cost
Indiree: APCS Installation Costs
Engineering
Consrucsan/field expenses
Contracto.-s fees
Start-up (2%) (1)
Pjfformancs tsst (1%) (1)
Contingencies (3%) (1)
Total indirect APCS installation co:t
Patnt booth retrofit cost (4):
TOTAL INSTALUVTED COST:
RTO - OACPS data (2)
S2.177.419 (1)
550,000 (3)
5111.371
539.097 (4%)(1)
52.427,337
597.115 (4%)(1)
5121.334 (S%K1)
5121,394 (5%X1)
512.139 (0.05%)(1)
5352.044
597,115 (4%) (1)
548,558 (2%) (1)
5121,394 (5%) (1)
548.553 (2%) (1)
524,279 (1%)(1)
572,337 (3%) (1)
S41Z741
50
53,192,372
RTO Vendor data
SI.535.700 (5)
550,000 (3)
S81.73S
539,097 (OAGPS Value)
$1.306.532
$97,115 (OAQPS Value)
580.200 (5)
5121.394 (OAQPS Value)
S12.139 (OAQPS Value)
$310,843
$35,500 (5)
(included)
(included)
$43,553 (OAQPS Value)
$24,279 (OAQPS Value)
$53,500 (5)
$161,837
SO
S2.279.2S7
Rotor/Recup Vendor data
51,600.000 (5)
5S0.GC0 (3)
532,500
556,000 (5)
51,793.500
571,940 (5)
589.925 (5)
533.925 (5)
58.993 (5)
5250.783
5430.000 (5)
(included)
(inciuded)
535.970 (5)
$17,985 (5)
553.955 (5)
5537,910
S3
52.537.193
(1) Unless otherwise specified, the factors were taken from the OAQPS Manual
(2) OAQPS Manual RTO capital cost assumptions indude:
- Costs reported are 1st quarter 1933 dollars; conversion data from OACPS manual supplements
- Formula: S = (2^04 X 10E5) 11.57Q
- Results: 1383 5 1995 5
S1.880.335 52.177,419
(") Auxiliary equipment is monitoring system
(/) Paint Soct.1 installation data from Acurex Environmental Design Group
(5) Manufacturers' estimate for system cost.
OPEP.ATING COSTS (1)
APCS
E'ecricsy (4)
N3tural gas (5)
Maintenance (S)
Miscellaneous
Paint Sccths
Maintenance Labor (6)(7)
E eci-ioty (4) (9)
-BIQ^AAESJatai2I£31.
4/-0.1 kw
12.3 M3tu/hr
4 fir/wk
S15.000 5/yr
S/hr S/yr
S28.21 S84.S13
S51.27 S191.314
S20.00 S4.000
$15,000
123.3
llrrwx
kW
$20.00
58.20
TOTAL ANNUAL OPERATING COST:
58.000
518,554
5321,527
RTO Vendor m
360
13.11
4
$15,000
8
103.3
Srtir S/yr
IcW (S) 521.50 564.800
MBfu/ftr (8 S5Z42 $181,022
hr/wfc
S/yr
hn\vk
kW
520
$4,000
$15,000
. PaortReeup Vender f81f 10%
$20.00 $8,000
58.20 '518,594
5291.416
207
5.40
520,00-0
8
103.3
kW (8)
MBIu/hr (8
tins**
S/yr
S/hr S/yr
$12 S37.2S0
S2S $134,100
S20 S^.000
$20,000
hriwk
kW
$20.00
56.20
S.-J.OOO
SW.594
$222,254
(1) Scottij operate 10 hours/day. S days/week, 50weeks/year
(2) RTO Assumptions for standarc and startup operations:
RTO operates at 95'/. thermal efficiency 10 hrs/day
°70 ocr-Hii 3;45 mi.-,djv -g «ji ,Ve (25 .VStu/hr) 5 days per-week
RTO operates sectional 1 hourrcay© full fire (2S MSTu/hr) 1 cay per week
[last two items aeos anual n.g. cast facer of (S/8tu"25 8tu/hr)*S0/0.05"t(5'*45/60) * 1]
OAQPS Assumptions for stanaard and startup conditions
RTO operates at 35% inermal efficiency 10 hrs/day
RTO operates additional 1.5 hr per day @ full fire (25 MBtu/tir)
(2) Additional OAQPS Manual assumptions:
14 inert pressure eras through system
fan/motor efficiency is 50% (e)
electncty calculated from [tie formula: 1.14E-4"Q"dp/e
(-) Siectriciy is 50.06/kWhr
(I) The (cllow.ng assumptions apply lo al control systems data sets:
Natural gas is 54/Mbtu
Oxidizer operaled at 1S50F
Hea: capacity of air is 0.255 3tu/lsF; density is 0.0733 IS/scf
Intat.e air is at an average temperature of 70F
Then* is no fuel value in exhaust gas
(S) Maintenance labor is 520/hr
(7) Maintenance items such as fi.Tcr replacement are the same for rearculating & nornrecireulating booths and are therefore net included
it] Manufacturers' estimate
(S-) Paint I5ootn operating data Iram Acurex Environmental energy audit/estimate: Sooths 1. 2 & 3 operated simultaneously in cngtnai configuration
(10) P.ctor concentrator achieves a 10:1 volume reduction
91
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Table 36. Summaiy of Cost Analysis Results Comparing Emission Control Costs With and
Without Recirculation/Flow Partitioning.
Control Technology
Cost Elements
(assumes a 12 year equipment life)
Operating Scenario
1,176 m3/min
(41,450 cfm)
Final Configuration
(Booths 1 & 2 operating)
3,285 m3/min
(116,000 cfm)
Initial Configuration
(Booths 1 & 2 operating)
4,064 m3/min
(143,500 cfm)
Initial Configuration
(Booths 1, 2 & 3 operating)
Regenerative Thermal Oxidizer
Paint Booth Modification Design
and Installation Costs
$ 350,000
$ 0
$ 0
RTO System Capital and
Installation Cost
$ 793,625
$1,782,300
$2,279,270
Booth + RTO System Annual
Operating Costs
$ 98,437
$ 235,520
$ 291,420
Total System Equivalent Uniform
Annual Cash Flow (EUAC)
$ 250,190
$ 473,000
$ 593,870
Rotor Concentrator/Recuperative Oxidizer
Paint Booth Modification Design
and Installation Costs
$ 350,000
$ 0
$ 0
Rotor/Recup System Capital and
Installation Costs
$1,363,800
$2,279,400
$2,597,200
Booth + Rotor/Recup System
Annual Operating Cost
$ 81,130
$ 173,790
$ 222,250
Total System Equivalent Uniform
Annual Cash Flow (EUAC)
$ 308,540
$ 476,000
$ 566,880
OAQPS Control Cost Manual Estimate for Regenerative Thermal Oxidizer
Paint Booth Modification Design
& Installation Costs
$ 350,000
$ 0
$ 0
RTO System Capital and
Installation Cost
$1,233,300
$2,664,660
$3,192,670
Booth + RTO System Annual
Operating Costs
$ 108,230
$ 262,500
$ 321,500
Total System Equivalent Uniform
Annual Cash Flow (EUAC)
$ 318,330
$ 616,100
$ 745,180
1 Only the cost of retrofitting Booths 1 and 2 are included for this scenario.
92
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SECTION 8
ENGINEERING CONCLUSIONS AND RECOMMENDATIONS
The data summarized in the preceding sections provide compelling evidence that
recirculation/flow partitioning and other ventilation system enhancements provide a safe and
efficient means of reducing VOC emission control costs for military paint spray booths.
8.1 PROGRAM CONCLUSIONS
The information collected for this spray booth recirculation technology demonstration
program demonstrates the successful application of various innovative technologies at a high
production maintenance facility and leads to the following conclusions:
• In non-recirculating booths, the presence of hazardous constituent compounds in the
vicinity of the booth operators can be attributed to the air flow conditions in the
booth, the target configuration, and the spray pattern created by the paint application
system. The combination of these parameters tends to create a "cloud" of over spray
particulate and solvent vapor, which often creates conditions in the vicinity of the
painter in which the OSHA Factor exceeds unity. For this reason, booth operators
should wear personal protective equipment (PPE) to ensure safe working conditions.
The Phase III test data conclusively demonstrate that recirculation does not cause an
increase in concentrations in this over spray "cloud," and therefore does not cause a
deterioration of working conditions in the booth [details provided in Section 6],
• For paint booth ventilation systems where standard engineering and administrative
controls as defined in 29 CFR 1910.10007 (i.e., a single pass ventilation system rated
at >125 fpm (38.18 m/h) linear velocity,} are not sufficient to achieve compliance
with worker exposure requirements. Personal protective equipment (PPE) should be
employed to ensure safe working conditions. Moreover, as indicated in Section 6,
recirculation in the MCLB paint booths does not have a measurable effect on the
specific constituent concentrations in the worker vicinity. Test data indicate that the
MCLB recirculation systems did not increase odor. Protective respiratory equipment
was required prior to modifying the booths, and was still required after modification:
details provided in Sections 4 and 6.
• The PPE systems currently employed in the MCLB paint booths have assigned
protection factors of 10 (cartridge respirators) and 25 (hooded air-line respirators).
93
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Reconciling protection factors with the constituent concentration data collected in the
painter vicinity indicates that a safe working environment is provided in recirculation
mode when the proper protective equipment is used [details provided in Section 6],
• All of the OSHA Factors reported herein were derived based on 8-hour OSHA PELs,
thus the OSHA Factors assume that the paint booth operators apply paint in the
booths for 8 hours per day. The typical MCLB painting intervals (the hours per 24
hour day that an individual is potentially exposed to paint fumes and over spray
particulate) do not exceed 4-5 hours a day. Therefore, actual OSHA Factors
exposures are at least 25% lower than those reported in Sections 4 and 6. This
provides an additional safety margin to the MCLB results. This approach may be
employed for any painting facility that operates on an 8 hour shift schedule to
determine a safe and efficient recirculation system.
• The test results from the Phase III demonstration study clearly indicate that the
partition height and corresponding recirculation rate projections determined from the
Phase I baseline study were correctly estimated. The Booth 1 and 2 results
demonstrate that an average OSHA Factor of approximately 0.5 was achieved
upstream of the fresh make-up air intake; this insured that the quality of the booth
intake air would be well below the 0.5 OSHA Factor target value. The Booth 3
results show that an OSHA Factor of much less than 0.5 is consistently achieved at
this location. When the dilution effects of the fresh make-up air are taken into
consideration, the intake air OSHA Factors calculated for all three booths conform
with the limit imposed by Equation 1 by a margin of at least 40% [details provided in
Section 6].
• As predicted a sufficient concentration gradient occurs at the MCLB paint booth
exhaust faces thus warranting the efficient use of the recirculation/flow partition
system. This is particularly true for Booths 2 and 3, which show a significant
decrease in concentrations above the 7-8 foot level [details provided in Section 6].
• The use of WD fans in a paint booth ventilation system provides a means of ensuring
compliance with the 100 fpm minimum flow rate requirements mandated under 29
CFR 1910.94,5 while simultaneously reducing ventilation system electrical usage to
the lowest possible level. Paint booth ventilation systems are typically constructed
using fixed-drive fans that are usually oversized to ensure adequate ventilation even
if the exhaust filters are heavily laden. This not only generates excessive exhaust
flows, but also creates an unnecessarily high electrical demand to operate the fans
and other HVAC equipment. Using VFDs in a booth ventilation system provides
numerous benefits, such as generating a consistent flow profile in the booth, reducing
electricity usage, minimizing heating and air conditioning requirements, and reducing
the capital, installation, and operating costs associated with both the VOC emission
control systems and the spray booths [details provided in Section 5],
94
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• The combined effects of enclosing Booth 2 and installing VFD fans successfully
reduced the total chrome concentration in the vicinity of the paint booth operator by
more than 80%. This decrease is doubtlessly due to the elimination of lateral flow
patterns, inertial flow entrance losses, and inconsistent flow profiles commonly found
in open or partially closed paint facilities equipped with fixed-drive fans.
. High performance particulate filtration systems are capable of reducing paint
over spray particulate in the paint booth exhaust. However, the Phase III test
results indicate the presence of trace levels of hexavalent chrome in the
recirculation ducts downstream of the exhaust filters. It therefore appears that
the 3-stage system may not achieve quite the filtration efficiency desired.
The manufacturer maintains that the presence of hexavalent chrome detected
in the recirculation duct is attributed to leakage around the third stage, and
that future design changes will improve the filter sealing characteristics.
Although the presence of hexavalent chrome impacts significantly to the
OSHA Factors calculated for the Booth 2 and 3 recirculation ducts prior to
addition of the dilution air, it is does not occur in sufficiently high
concentrations to cause the calculated intake air to exceed the OSHA safety
level established by Equation 2 [details provided in Section 6],
• To minimize plenum zone leakage and ensure separation between the high
concentration air stream (vented to the APCS) and the low concentration air stream
(recirculated back into the booth), an efficient seal around the partition within the
plenum is necessary.
• A detailed ventilation system performance evaluation was performed over the 7
month period following the Phase III test. During this evaluation, tremendous
variations were noted with respect to painter technique, ability, and coating usage. In
several instances, some painting techniques cause unnecessary conversions to single-
pass operation; this in turn cause booth operating delays. These techniques should be
adjusted to reduce or eliminate delays.
• Multiple paint spray booths equipped with recirculation/flow partitioning and in high
production environments can operate using most conventional or innovative APCS.
The booth and APCS operations must are properly integrated [details provided in
Section 5],
• An FTIR can be adapted and programmed to serve effectively as a safety monitor for
paint booth recirculation system applications. The FTIR instrument has
demonstrated short term success in obtaining accurate and reliable speciated organic
concentration data. The long term applicability of FTIR instrumentation in this
application is yet to be determined [details provided in Sections 2 and 6],
95
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8.2 PROGRAM RECOMMENDATIONS
Several technology and system recommendations can be made based on the results
obtained from the EPA/USMC Technology Demonstration Program, including:
• Industrial and military paint booth facilities should consider recirculation as an
efficient means of reducing paint booth exhaust volume flow rates and achieving cost
effective VOC emission control goals.
• To minimize worker exposure to hazardous constituent concentrations, facilities
should furnish paint booth operators with PPE having the highest assigned protection
factor that may be reasonably accommodated. For example, both cartridge
respirators and hooded air-line respirators may be used in the MCLB booths, yet the
hooded air-line respirator affords a higher level of protection than the cartridge type
respirator. Use of the hooded air-line respirator should be actively encouraged.
• Although not required by OSHA, facilities that contemplate installing recirculation
ventilation should consider including a safety monitoring system in the design. This
would insure that excessive pollutant concentrations which exceed OSHA limits, do
not occur in the recirculating stream intake air.
• A painter training program will reduce paint both operating delays, as well as
enhance facility operating efficiencies by reducing facility labor and coating usage.
96
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SECTION 9
SUMMARY OF QUALITY ASSURANCE/QUALITY CONTROL RESULTS
A number of quality assurance/quality control (QA/QC) procedures were implemented
to assess the quality of the data collected during Phase I (Baseline Study) and Phase III
(Demonstration Study) of the EPA/USMC Technology Demonstration Program. The overall
results of the QA/QC efforts undertaken for this program are summarized in this section, along
with a brief description of the data quality analysis procedures that were implemented. The
following subsections briefly address the overall quality of data achieved, and provide highlights
of principal QA/QC issues considered during the Baseline and Demonstration Studies. A
separate subsection summarizes the results of a field audit performed under the direction of the
EPA APPCD Quality Assurance Officer (QAO) during the Demonstration Study.
9.1 OVERALL DATA QUALITY AND CRITICAL MEASUREMENT QUALITY
Nearly all the objectives established for the Data Quality Indicators (DQI) were met for
both the Baseline (Phase I) and the Technology Demonstration (Phase III) portions of the
EPA/USMC Technology Demonstration Program. As indicated in the Technology
Demonstration Study Quality Assurance Project Plan (QAPjP) submitted to the EPA QAO in
August 1995, the most critical measurements in the EPA/USMC Program were the hazardous
constituent concentrations in the recirculated stream. These data are necessary to demonstrate
that, under high throughput (worst case) conditions, the calculated OSHA factor in the
recirculated stream does not exceed 0.5. The DQI objectives specified for the recirculation duct
measurements were selected to ensure an adequate safety margin in this calculation.
All of the recirculation duct measurement DQI objectives were met or exceeded with the
exception of the accuracy level for hexamethylene diisocyanate (HDI). The results of a multi-
level spike and recovery analysis for the EPA Draft Isocyanate sampling procedure indicated
that a 125% recovery was achieved at the low concentration range (1.0 //g), but only 64%
recovery was achieved at higher spikant concentrations (10-50 fig). Fortunately, the majority
of the recirculation duct HDI concentrations were found at or below the detection level, thus the
high spike/recovery factor is applicable to the field test results obtained. It may therefore be
concluded that, despite the broad measurement accuracy range indicated by the spike/recovery
results, the HDI levels measured in the recirculation ducts are perhaps overpredictive, which
yields a more conservative (safe) OSHA Factor. In summary, all the QA/QC results obtained
indicate that the recirculation/flow partition ventilation systems installed on the Barstow MCLB
paint booths operate well within an acceptable margin of safety.
97
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9.2 CALCULATION OF DATA QUALITY INDICATORS
The four data quality indicators that were considered in planning and executing the
Baseline and Demonstration Studies were accuracy, precision, completeness and
representativeness; the calculation procedures for each of these parameters are presented
separately below.
9.2.1 Accuracy
Accuracy of the integrated samples is assessed by spiking a known quantity of the target
analyte(s) onto clean sampling media, and subsequently analyzing the spiked samples along with
the field samples to determine the percent recovery achieved. The percent recoveiy result
provides a measure of the sampling bias which is introduced via sample handling and analysis.
The percent recoveiy is calculated from the expression:
,,, ,, Spiked Sample Result - Spiked Amount inri
% Recovery - — x 100
Spiked Amount
In many cases, a multi-level spike/recovery analysis is performed in which replicate spike
samples are prepared at several concentrations which represent the concentration range found in
the field samples. For each spike level, the percent recovery for the replicate spike samples are
averaged to derive the overall percent recovery at that particular spikant level.
The paint volatile content and density measurement accuracy is assessed by comparing
the sample results to published values obtained from manufacturer data.
9.2.2 Precision
Precision is defined as the reproducibility of measured results. Method precision for the
NIOSH and OSHA samples is assessed through the collection and analysis of side-by-side
duplicate samples that are collected simultaneously. The relative percent difference between
these duplicate results defines the precision limits, and is calculated from:
RPD =
\X, -X
x 100
avg
98
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The dynamic nature of paint booth operations may cause poor reproducibility in some of
the side-by-side sample results. It is therefore important that the overall sampling variability be
characterized; this was accomplished for the Demonstration Study results by pooling the
individual RPD values obtained for each measurement type to assess an overall RPD value. To
establish how well this "pooled" RPD value represents actual measurement RPDs, the relative
standard deviation is determined according to the following equation:
2 (RPD.-RPD f
„2 _ V V ' avS'
*RPD ^ Z 77
The precision of paint density and percent volatile measurements is determined from
RPD results for duplicate samples. For continuous monitors; instrument precision is determined
by periodically comparing zero, span, and reference gas response results.
9.2.3 Completeness
Completeness is defined as the ratio of the number of valid analytical results obtained to
the number of samples required in the test matrix. Causes for not producing valid analytical
results include sample loss from breakage, mis-identification of samples, or errors in the sample
recovery or analysis procedures. Completeness is derived from the following equation:
Number of Valid Analytical Results Obtained ^
Total Number of Proposed Samples
9.2.4 Representativeness
The dynamic nature of the Barstow MCLB paint booth operations raises concerns over
proper test planning, because the sampling must be performed in such a way as to preserve
process representativeness. Moreover, it was important that the test results represent a relatively
high throughput rate for the booths to ensure subsequent safe operation under worst case
conditions. To achieve conservative and representative results, all the sampling events were
carefully coordinated with facility operators, and detailed coating usage and throughput records
were collected during each test series.
99
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9.3 SUMMARY OF BASELINE STUDY QA/QC RESULTS
There were several sets of integrated and continuous sampling measurements collected
during the Baseline Study completed in the Fall of 1993. Specific information relating to the
sampling and analysis results are provided in Appendix C along with details pertaining to the
data quality evaluation effort. A Baseline Study QA/QC assessment summary is provided in
Table 37, which indicates the DQI objectives and results obtained for each measurement
parameter. Measurement parameters that exceed the DQI objectives are indicated in boldface.
The DQI objectives were taken from the Category III QAPjP which was submitted to and
approved by the EPA QAO prior to initiating any test activities.
All of the DQI objectives established for the Baseline Study were met with the exception
of OSHA 42 measurement precision. As indicated in Appendix A, OSHA 42 is an integrated
isocyanate sampling procedure in which sample air is pulled through a small filter cassette. The
duplicate samples that were collected to assess method precision were arranged in a side-by-side
configuration to ensure replicate results insofar as possible. The variability noted in the OSHA
42 precision analysis is doubtlessly due to sample orientation; although considerable effort was
expended to ensure that side-by-side samples were oriented identically, such a configuration was
not always achievable. The difficulties associated with proper orientation of duplicate samples
is also reflected in the relatively high precision results reported for the NIOSH 500 and NIOSH
7300 samples, which are collected in a manner similar to the OSHA 42 procedure.
At the inception of the Baseline Study, it was anticipated that a significant level of
sample variability could occur for all the NIOSH and OSHA test methods. To counter the
impact of sample variability, a large sample set was collected. The results of multiple exhaust
face measurements from the Baseline Study indicate that constituent concentration profiles
remain fairly consistent, thus it may be concluded that the test matrix contained adequate sample
redundancy and test event repetitions to neutralize any effects of individual sample variability.
9.4 SUMMARY OF TECHNOLOGY DEMONSTRATION STUDY QA/QC RESULTS
Specific information relating to the sampling and analysis results obtained for the
Demonstration Study are provided in Appendix D along with details pertaining to the data
quality evaluation effort. A QA/QC assessment summary for the technology Demonstration
Study is provided in Table 38, which indicates the DQI objective for each measurement
parameter as well as the results obtained. The measurement parameters which exceed the DQI
objectives are indicated in boldface. The DQI objectives were taken from the Category III
QAPjP submitted to and approved by the EPA QAO prior to initiating any test activities.
All but two of the DQI objectives established for the Technology Demonstration Study
were met. The fact that the NIOSH 7300 precision results fell outside of the DQI objective is
attributed to sample orientation, which caused similar problems for the Baseline Study OSHA 42
sampling efforts. For the reasons mentioned in Section 9.3, it is assumed that the impact of the
NIOSH 7300 precision results on overall program conclusions is negligible.
100
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Table 37. Summary of Data Quality Achieved for the Phase I Baseline Study
Measurement
Parameter
Measurement
Method
Precision (RPD)
Accuracy 1 (%)
Completeness
Objective
Result
Objective
Result
Objective
Result
Particulate
NIOSH 500
<35%
24%
NA
NA
>90%
99%
EPA Method 5
NA
NA
NA
NA
>90%
96%
Metals
NIOSH 7300
<35%
32.5%2
< ± 30%
-7%
>90%
97%
EPA Method 0060
NA
NA
< ± 30%
19%
>90%
100%
Organics
NIOSH 1300
<35%
17%3
< ± 30%
8%4
>90%
94%
EPA Method 25A
<20%
1%
< ± 20%
< 0.8%
>90%
100%
Isocyanates
OSHA 42
<35%
45%
< ± 30%
-23%
>90%
96%
NIOSH 5521
<35%
4%
< ± 30%
-2%
>90%
100%
Paints
Density
<20%
ND5
< ± 30%
2.7%
>90%
100%
% Volatile
<20%
6%
< ± 30%
5.0%
>90%
100%
Air Flow
EPA Method 2
<20%
2.96
< ± 10%
13%
>90%
100%
Anemometer
<20%
5.0
< ± 40%
20%
>90%
100%
Accuracy as a measure of method bias determined from percent recovery data.
Averaged over all compounds considered; actual average precision RPD for zinc and chrome ranged from 25% to 40%.
Averaged over all compounds considered; actual average precision RPD for all compounds ranged from 9% to 41%.
Averaged over all compounds considered; actual average method bias percentage for all compounds ranged from +7% to -19%.
This analysis was not performed.
These results derived from Booth 1 data only, because Booth 2 flow rates could not be measured via EPA Method 2.
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Table 38. Summary of Data Quality Achieved for the Phase II Technology Demonstration Study
Measurement
Parameter
Measurement
Method
Precision (RSD)
Accuracy (%)'
Completeness
Objective
Result
Objective
Result
Objective
Result
Metals
NIOSH 7300
<40%
57%
< ± 30%
-13% to +2%2
>90%
96%
EPA Method 0060
NA
NA
< ± 30%
+2% to +9%3
>90%
93%
EPA 0061 (Cr*6)
NA
NA
< ± 50%
-3% to +3%3
>90%
100%
Organics
NIOSH 1300
<40%
18%
< ± 30%
Avg: -7%,
Range: -49 to +3%4
>90%
97%
EPA Method 25A
<20%
0.7%
< ± 20%
0.7% - 8.9%
>90%
100%
Phosphoric Acid
NIOSH 7903
<40%
0%
< ± 30%
-28% to +1%3
>90%
100%
Isocyanates
OSHA42
<40%
8%
< ± 30%
-27% to +20%3
>90%
103%
EPA Draft Method
NA
NA
< ± 30%
-54% to +25%3
>90%
100%
Paints
Density
<20%
1%
< ± 30%
±3%
>90%
100%
% Volatile
<20%
3%
<±30%
±17%
>90%
100%
Air Flow
EPA Method 2
<20%
1.5%
< ± 40%
3% - 38%
>90%
100%
Anemometer
<20%
0.5%
>90%
100%
Accuracy as a measure of method bias determined from percent recovery data.
Bias determined from spike/recovery of chrome only; range indicates results over various spikant levels.
Bias determined from spike/recovery; range indicates results over various spikant levels.
The percent recovery varied as a function of compound and spikant levels (three spikant levels were used). The percent recovery
range for all the compounds except benzyl alcohol was 51% -103% (average is 93%). The average recovery
for benzyl alcohol was 21%, however this compound was never measured above the detection level in any samples, thus the low
recovery factor has no impact on data quality.
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The high variability in the spike/recovery results obtained for the EPA Draft Isocyanate
Method provides compelling reasons to evaluate the overall success of this method in more
detail. This is particularly appropriate in view of the fact that the method is still in draft form,
thus the sampling and analysis procedures are not completely finalized. As indicated in Section
9-1, the impact of this variability on the overall results of the EPA/USMC Technology
Demonstration Program is considered small, and in fact may indicate that the recirculation duct
isocyanate results obtained are rather conservative. However, other issues of concern related to
this method were noted during the sampling and analysis activities, including:
• Background Levels - The isocyanate train sampling solutions were prepared in the
field by combining a pre-measured volume of reagent grade toluene with a pre-
measured amount of reagent grade l-(2-pyridyl)piperazine solution in accordance
with the method requirements. The sample solutions were prepared fresh every 1-2
days, and in accordance with QAPjP requirements, train blank and solution blank
samples were prepared for each booth test event. When the analytical results were
reviewed, it was found that two-thirds of the Booth 1 field, samples and all of the
Booth 3 field and blank samples were at or below the method detection level.
However, all the blank samples from Booths 1 and 2 indicated contamination at
approximately 10 times the detection level, and similar amounts were measured in
the field samples as well. The only HDI source at the facility is the topcoat material,
yet the reagents and samples were stored far away from the paint storage area.
Moreover, the use of isocyanates compounds is typically very specific and
controlled, thus the presence of a second, unknown HDI source is unlikely. Because
it is a relatively new method which has not yet found widespread use, little is known
about potential interferents.
• Overall Poor Recovery Efficiencies - The multi-level isocyanate spike and recovery
results indicate that reasonable recovery efficiencies are easily achieved at low
spikant levels. However, the results obtained at higher spike levels (10 times over the
detection limit) were not encouraging. No reason for the poor recovery efficiency
could be found, but fortunately it does not appear to impact overall program results.
In planning the Demonstration Study tests, it was anticipated that the highest isocyanate
concentrations would be found in the Booth 1 recirculation ducts, because Booth 1 is used
exclusively for topcoat applications, and typically has a high topcoat usage rate. The fact that
the first six recirculation duct sampling results from Booth 1 and of all the Booth 3 recirculation
duct sampling results indicate that no isocyanates were present implies that 1) the isocyanates
occur largely in the solid phase (in the polymeric form, rather than the monomelic form); and 2)
the advanced filtration system effectively eliminates these solid phase isocyanates. The
presence of HDI in half the Booth 1 recirculation duct samples and all of the Booth 2
recirculation duct samples at approximately the same levels measured in the blank samples
raises concerns regarding contamination. As such, the recirculation duct OSHA Factors
calculated for Booths 1 and 2 assume that the isocyanate concentrations are at the method
detection limit.
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9.5 EPA FIELD AUDIT RESULTS
During the technology Demonstration Study, the EPA Quality Assurance Office
conducted a field audit. The EPA staff prepared several field spike samples that were submitted
for analysis to the appropriate laboratory with the field samples that were collected. The
analytical results that were obtained for the field spike samples as well as the standards that were
also submitted are summarized in Tables 39 and 40. Both uncorrected and corrected field spike
sample results are reported in Table 39. Please note the following:
1) The factors that were employed for the field spike corrections are indicated in Table
39; these factors were obtained from the multi-level spike and recovery study results
provided in Appendix D. The appropriate recovery factor was identified based on the
quantity measured in the spiked sample. For example, the results indicate that
approximately 122 /ug of MEK was spiked on the sample, thus the 81% average MEK
recovery obtained for the 333 /ug lab spike level was used for the correction factor.
2) For the NIOSH 1300 and NIOSH 7903 sampling activities, two sample tubes were
placed in series to ensure 100% collection of the sampled constituents. The
laboratory was instructed to analyze all front tubes, and further instructed to analyze
the back tubes only if the front tube results indicated the possibility of breakthrough.
To distinguish front tubes from back tubes, all the front tubes were denoted with the
suffix "a", and back tubes were denoted with the suffix "b". Unfortunately, the EPA
field spike samples were submitted with identification numbers that included the "a"
and "b" suffixes, thus the laboratory only analyzed the field spike samples denote
with an "a". This oversight was not recognized until nearly two months after the
samples were submitted. Although the samples were then analyzed immediately, it is
likely that the results obtained from these two field spike samples are skewed. EPA
may therefore want to consider disregarding the results reported for the samples
identified as B2PH4Plb and B204Plb.
3) The analytical laboratory did not measure the volume of the hexavalent chrome
standard prior to analysis, thus the total mass found in the sample could not be
reported. However, it is estimated the initial volume was approximately 9 -10 ml.
4) The zinc standard was submitted with the hexavalent chrome standard to the
laboratory performing the Booth 2 and 3 Method 0061 analyses. This is because zinc
occurs only in combination with the hexavalent chrome found in the wash primer
(which is used only in Booths 2 and 3), and not with the trivalent chrome found in the
topcoat material (which is the only material applied in Booth 1). However, due to
field sampling crew errors, the Method 0061 train fractions collected from the Booth
2 and 3 sampling efforts were not sufficiently recovered to allow analysis for total
chrome and zinc, thus the Method 0061 analyses performed on the field samples did
not include total chrome or zinc.
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Table 3 9. Summary of EPA Field Spike and Analysis Results
Sampling Procedure
Sample #
Target Analyte
Uncorrected
Og)
EPA Method 0061
B2C10NR
Cr'6
0.561
B2C10SR
Cr'6
0.369
EPA Method 0060
B1M10NR
Total Chrome
1.75
B1MI0SR
Total Chrome
1.96
NIOSH 7300
B2M4P1
Chrome
Zinc
13.1
24.8
B2M4P2
Chrome
Zinc
A 1 i
2.41
OSHA42
B2I4P1
HDI
< 0.06
B2I4P2
HDI
0.19
EPA Draft Method
B2110NR
HDI
16.2
B2I10SR
HDI
14.9
NIOSH 7903
B2PH4Pla
Phosphoric Acid
9.87
B2PH4Plb'
Phosphoric Acid
145
NIOSH 1300
B204Pla
MEK
Ethyl acetate
n-Butanol
MIBK
Toluene
Butyl Acetate
MIAK
PGMEA
Ethyl benzene
Xylene
TMB
Hexyl Acetate
Benzyl Alcohol
122
183
120
<7.5
173
192
165
< 7.5
203
144
165
173
<7.5
B204Plb'
MEK
Ethyl acetate
n-Butanol
MIBK
Toluene
Butyl Acetate
MIAK
PGMEA
Ethyl benzene
Xylene
TMB
Hexyl Acetate
Benzyl Alcohol
64.6
195
not reported
<7.5
175
102
111
<7.5
215
150
170
183
<7.5
1 These tubes were not analyzed with original group of samples. See comments in text.
105
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Table 40. Analytical Results of EPA Submitted Standards.
Method
Analyte
Analytical Results
EPA 0061
Hexavalent Chrome 1
9.6 E+5 ug/L
EPA 0060
Total Chrome
8.6 mg
Zinc2
Not analyzed
EPA Draft Isocyanate
HDI
No results
NIOSH 7903
Phosphoric Acid
28.4 mg
NIOSH 1300
MEK
10.31 mg
Ethyl acetate
11.68 mg
n-Butanol
11.62 mg
MIBK
< 7.5 n g
Toluene
11.31 mg
Butyl Acetate
11.94 mg
MIAK
< 7.5 //g
PGMEA
18.43 mg
Ethyl benzene
12.62 mg
Xylene
9.39 mg
TMB
11.2 mg
Hexyl Acetate
10.73 mg
Benzyl Alcohol
< 7.5 y.g
EPA Method 25A
Propane
97 ppm
1 See comment 3 section 9.5.
2 See comment 4 section 9.5.
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REFERENCES
1. Aver. J. and Wolbach. C.D.. Volatile Organic Compound and Particulate Emission
Studies of AF Paint Booth Facilities: Phase I, EPA-600/2-88-071 (NTIS ADA 198-902),
December 1988.
2. Standard for Spray Finishing Using Flammable and Combustible Materials, NFPA No.
33, 1985.
3. Ayer, J. and Hyde, C., VQC Emission Reduction Study at the Hill Air Force Base
Building 515 Painting Facility, EPA -600/2-90-051 (NTIS ADA 198-092), September
1990.
4. Hughes, S., Ayer, J., Sutay, R., Demonstration of Split-Flow Ventilation and
Recirculation as Flow-Reduction Methods in an Air Force Paint Spray Booth, Volume I,
Air Force Report Number AL/EQ-TR-1993-0002, EPA Report Number EPA-600/R-94-
214a, July 1994.
5. U.S. Department of Labor, Occupational Safety and Health Administration (OSHA), 29
CFR Subpart G, 1910.94, "Ventilation," 1974.
6. U.S. Department of Labor, Occupational Safety and Health Administration (OSHA), 29
CFR 1910.107, "Spray Finishing Using Flammable and Combustible Materials," 1987.
7. U.S. Department of Labor, Occupational Safety and Health Administration (OSHA), 29
CFR 1910.1000, Subpart z, Toxic and Hazardous Substances, 1987.
8. NIOSH Manual of Analytical Methods, Third Edition, National Institute of Occupational
Safety and Health, NTIS PB86-116266, Updated May 1989.
9. OSHA 42 Airborne Di-isocyanate Sampling and Analysis Protocol, Occupational Safety
and Health Administration, Carcinogen and Pesticide Branch, OSHA Analytical
Laboratory, February 1983, unpublished.
10. Ibid (8)
11. Ibid (8)
12. EPA Method 0060, Code of Federal Regulations, Part 60 Appendix A, Test methods,
1989.
13. Ibid (8)
107
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14. EPA Method 25 A, Code of Federal Regulations, Part 60 Appendix A, Test Methods,
1989.
15. EPA Method 5, Code of Federal Regulations, Part 60 Appendix A, Test Methods, 1989.
16. EPA Method 2, Code of Federal Regulations, Part 60 Appendix A, Test Methods, 1989.
17. EPA Method 0061, Test Methods for Evaluating Solid Waste: Physical/Chemical
Methods, 3rd edition, final update: May 1997, Vol.2, EPA-530/SW-846.
18. Ibid (8)
19. Hazard Controls, Control of Paint Overspray in Autobody Repair Shops, DHHS (NIOSH)
Publication No. 96-106, January 1996.
20. OAOPS Control Cost Manual (4th Edition). EPA-450/3-90-006 (NHS PB90-169954);
January 1990 and Updates (January 1992, October 1992, March 1994).
108
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