r/EPA
AL/EQ-TR-1993-0002
EPA/600/R-94/214a
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DEMONSTRATION OF SPLIT-FLOW VENTILATION AND RECIRCULATION AS
FLOW-REDUCTION METHODS IN AN AIR FORCE PAINT SPRAY BOOTH
S. Hughes, J. Ayer, R. Sutay
ARMSTRONG LABORATORY
ENVIRONICS DIRECTORATE
AL/EQS-OL
139 Barnes Drive, Suite 2
Tyndall AFB FL 32403-5323
Acurex Environmental Corporation
555 Clyde Avenue
P.O. Box 7044
Mountain View, CA 94039
US EPA/AEERL
MD-61
Research Triangle Park NC 27711
July 1994
Final Technical Report for Period February 1991 - October 1992
AIR FORCE MATERIEL COMMAND
.TYNDALL AIR FORCE BASE, FLORIDA 32403-5323,
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NOTICES
This report was prepared as an a account of work sponsored by an agency of the United
States Government. Neither the United States Government nor any agency thereof, nor any
employees, nor any of their contractors, subcontractors, or their employees, make any warranty,
jexpress or implied, or assume any legal liability or responsibility for the accuracy, completeness,
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process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily
constitute or imply its endorsement, recommendation, or favoring by the United States Government
or any agency, contractor, or subcontractor thereof. The views and opinions of the authors
expressed herein do not necessarily state or reflect those of the United States Government or any
agency, contractor, or subcontractor thereof.
When Government drawings, specifications, or other data are used for any purpose other
than in connection with a definitely Government-related procurement, the United States
Government incurs no responsibility or any obligation whatsoever. The fact that the Government
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to be regarded by implication, or otherwise in any manner construed, as licensing the holder or any
other person or corporation, or as conveying any rights or permission to manufacture, use, or sell
any patented invention that may in any way be related thereto.
This technical report has been reviewed by the Public Affairs Office (PA) and is releasable
to the National Technical Information Service (NTIS), where it will be available to the general
public, including foreign nationals.
This report has been reviewed and is approved for publication.
D. WANDER, PhD MICHAEL G. KATONA, PhD '
Manager, Air Pollution Control Technology Chief Scientist, Environics Directorate
EDWARD N. COPPOLA, Maj.,USAF NEIL J. LAMB, Col, USAF, BSC
Chief, Environmental Compliance Division Director, Environics Directorate
=PA UC
IfOPINl© 2771111
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1. AGENCY USE ONLY (Lftvt blank) 12. REPORT DATE I 3. REPORT TYPE AND DATES COVERED
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4. TITLE AND SUBTITLE
Demonstration of Split-flow Ventilation and Recirculation as
Flow-reduction Methods in an Air Force Paint Spray Booth
6. AUTHOR(S)
S. Hughes and J. Ayer; R. Sutay, CIH (Section VI)
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESSES)
Acurex Environmental Corporation
555 Clyde Avenue
P.O. Box 7044
Mountain View, CA 94039
9. SPONSORING/MONITORING AGENCY NAME(S) AND AODRESS(ES)
U.S. EPA Armstrong Laboratory
AEERL Environics Directorate
MD-61 AL7EQS-OL
Research Triangle Park. NC 2771 1 139 Barnes Drive, Suite 2
Tyndall AFB, FL 32403-5323.
11. SUPPLEMENTARY NOTES
1. Responsible individual: Joseph D. Wander, (904) 283-6240
2. Office symbol: AL/EQS-OL
3. Availability of report is specified on inside front cover.
12a. DISTRIBUTION/AVAILABILITY STATEMENT
Approved for public release; distribution is unlimited.
5. FUNDING NUMBERS
Contract 68-D2-0063
Work Assignment 0/002
Program element 63723F
Project 2103
Task 70
Work unit accession 97
8. PERFORMING ORGANIZATION
REPORT NUMBER
FR-93-115
10. SPONSORING/MONITORING
AGENCY REPORT NUMBER
AL7EQ-TR-1 993-0002
FPA/600/R-94/214a
12b. DISTRIBUTION CODE
13. ABSTRACT (Maximum 200 word*)
During a series of painting operations in a horizontal-flow paint spray booth at Travis AFB, CA,
baseline concentrations of four classes of toxic airborne pollutants were measured at 24 locations
across a plane immediately forward of the exhaust filters, in the exhaust duct, and inside and outside
the respirator in the painter's breathing zone (BZ). The resulting data were analyzed and used to
design a modified ventilation system that (1) separates a portion of the exhaust exiting the lower
portion of the booth, which contains a concentration of toxic pollutants greater than the average at
the exhaust plane (split-flow); and (2) provides an option to return the flow from the upper portion of
the exhaust to the intake plenum for mixing with fresh air and recirculation through the booth
(recirculation). After critical review by cognizant Air Force offices, and an experimental
demonstration showing that a flame ionization detector monitoring the air entering the booth is able
to detect excursions above the equivalent exposure limit for the solvents in the paint, the exhaust
duct was reconfigured for split-flow and recirculating ventilation. A volunteer painter was briefed on
the increased risk of exposure during recirculation, and on the purposes and possible benefits of this
study. He then signed an informed consent form before participating in the recirculation tests. A
series of tests generally equivalent to the baseline series was conducted during split-flow and
14. SUBJECT TERMS
Air pollution, emission control technology, exhaust
recirculation, paint spray booth, ventilation
15. NUMBER OF PAGES
Vol. I, 132; Vol. II, 179
16. PRICE CODE
17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION OF 19. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACT
OF REPORT THIS PAGE OF ABSTRACT
Unclassified Unclassified Unclassified
NSN 7540-01-280-5500
Standard Form 298 (Rev. 2-89)
Prescribed by ANSI Sid. 239-18
298-102
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Unclassified
SECURITY CLASSIFICATION OF THIS PAGE
recirculating ventilation, and three tests were performed during only split-flow ventilation. Data from the
two sets of tests show that pollutants concentrate toward the bottom of the booth during ordinary
painting operations; that local processes associated with circulation near the paint spray gun contribute
far more to the net exposure to the painter than do toxic pollutants in-the recirculated air stream; and
that, under well-ventilated conditions, including split-flow and recirculation of a large fraction of the
exhaust air, equivalent exposures to airborne toxic pollutants (calculated as the sum of 8-hour, time-
weighted concentrations of toxicants divided by their respective Permissible Exposure Limits) should not
exceed 0.25 in the intake air. An economic analysis of costs to implement thermal or catalytic
incineration, with and without flow reduction by split-flow and recirculating technologies, projects
substantial savings, such that the payback periods for inclusion of flow-reduction technology during
installation of the control device are about 1 year. The recirculation of air in the paint spray booth did not
result in an increase in air contaminants that would exceed the capability of proper respiratory
protection. The magnitude of the incremental increase in exposure derives primarily from particulates in
the recirculated air. This is defined by the particulate removal efficiency of the particulate controls, which
can be compromised by improper maintenance. However, with proper design, installation, and
maintenance, the increment to risk is normally less than the round-off errors in the calculation of net job-
related risk. Because the cost benefit is obtained at an increase of risk of exposure to painters, the
acceptability of this cost-benefit tradeoff will have to be resolved by industrial hygiene functions at both
policy and local levels before this advance can be implemented at Air Force installations.
Unclassified
SECURITY CLASSIFICATION OF THIS PAGE
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SUMMARY
A. OBJECTIVE
The objective of this program was to demonstrate, that split-flow and recirculating
ventilation, individually and in combination, are safe and cost-effective methods of reducing paint
spray booth exhaust flow rates to lower the costs both of conditioning intake air and of
controlling volatile organic compound (VOC) emissions in exhaust air.
B. BACKGROUND
This study was part of an extended program of investigations into the cost and efficacy
of innovative approaches for bringing U.S. Air Force industrial operations into compliance with
current and anticipated air pollution environmental standards. Adequate ventilation of paint spray
booths requires the movement of large quantities of air, which are slightly contaminated during
passage through the booth. Air exhausted from this process requires decontamination, which,
although technically achievable at operating flow rates, can be prohibitively expensive. Because
emission-control costs depend on the volume of exhaust air being treated, considerable savings
can be realized through the application of an acceptable flow-reduction method.
A first principle of industrial hygiene is to employ engineering controls to their limit before
invoking personal protection. In dealing with exposures to airborne toxics, the mainstay
engineering device is enhancement of ventilation. However, increased ventilation creates
enormous volumes of slightly contaminated air, which must be treated before discharge and, in
many situations, the cost of such treatment is excessive. In such circumstances, a judgment
must be made about the relative cost in increased exposure compared to the economic benefit
in decreased operating cost. The goal of this study was to provide experimental data to support
the development of a general Air Force position and objective criteria for local decisions about
the acceptability of using flow-reduction methods in paint spray booths, based on local health-
risk/cost-benefit considerations.
C. SCOPE
This study comprised two sets of experimental measurements in Booth 2, Building 845,
Travis Air Force Base (AFB), California, plus the results of an ancillary effort conducted at
Research Triangle Institute (RTI) to verify experimentally that the flame ionization detector (FID)
used in the ventilation control loop is within its linear response range at the equivalent exposure
limit for the mixture of solvents present in the mixed topcoat. The first set of experimental
measurements was a baseline characterization of the distribution of toxic pollutants at the
exhaust face and in the exhaust duct of Booth 2. These data, the RTI results, and the test plan
for the second set of tests were reviewed by HQ AFLC/SGBE before approval was given to
proceed with the recirculation tests. The test plan and engineering drawings were reviewed by
the Fire Department, Safety Office, and Civil Engineering Office at Travis AFB and approved
before implementation. For the second set of tests, the ductwork in Booth 2 was reconfigured
to separate exhaust streams from the top and bottom of the booth (split-flow) and to return the
upper exhaust stream to the intake plenum for recirculation through the booth. The volunteer
painter was briefed and signed an informed consent form before participating in the study.
During separate painting sessions, several sets of concentration measurements were made of
VOCs, particulates, heavy metals, and isocyanates. Equivalent exposures (E^ were calculated
from these data, and projections of £m were made for a range of recirculation ratios, together
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with an economic analysis of the corresponding costs to install flow reduction technology and
apply VOC emission control devices.
D. METHODOLOGY
Per standard Travis AFB policy, painters in Booth 2 wear a protective jump suit, a
separate hood, and an airline respirator. To determine exposure concentrations, sampling was
performed simultaneously inside and outside the respirator, at 24 locations at the exhaust face,
in the exhaust ducts, and, during the second set of tests, at three locations at the face of each
of the two intake filters. To determine environmental contributions to the load of pollutants,
background air samples were collected at the back of the booth prior to the release of any paint-
derived materials. Standard sampling methods used were National Institute of Occupational
Safety and Health (NIOSH) Method 1300 (integrated measurement of individual organic species),
Bay Area Air Quality Management District (BAAQMD) Method ST-7 and U.S. Environmental
Protection Agency (EPA) Method 25A (continuous measurement of total organic concentration),
Occupational Safety and Health Administration (OSHA) Method 42 (filter faces and ducts) and
NIOSH Method 5521 (painter and ducts) (isocyanates), EPA Method 5 and NIOSH Method 500
(particulate), and EPA Draft Multiple Metals and NIOSH Method 7300 (metals). Paint usage was
determined by weighing the gun after each filling and at the end of each painting session. The
percent volatile content of the paint was determined gravimetrically, as percent weight loss to
evaporation. Airflows were measured with an anemometer (American Conference of
Governmental Industrial Hygienists [ACGIH]) in the booth and with a pitot tube (EPA 2) in the
exhaust ducts. Painting start and stop times were recorded manually by an observer, stationed
at the rear of the booth, who also noted the dimensions and locations of workpieces painted,
coatings applied, and other details. Projections of equivalent exposures at different recirculation
ratios were calculated by a Lotus 1-2-3 program written at U.S. EPA-Air and Energy Engineering
Research Laboratory (AEERL).
E. TEST DESCRIPTION
In both test series, representative workpieces were prepared and coated according to
normal operating procedures. During each such painting run, measurements were made of one
of the four pollutant classes using the methods specified in Section D. A typical painting session
lasted 30 to 90 minutes, and included postpainting cleaning of the paint spray gun with methyl
ethyl ketone (MEK) and tidying up of the area. In general, two sets of tests were accomplished
during an 8-hour shift, corresponding to a typical workday. A complete series of blood chemistry
parameters was determined for the painter at the conclusion of the testing.
F. RESULTS
Concentrations of airborne toxic pollutants are recorded in the tables of the report.
Strontium chromate occurs as the major contaminant during primer coating and was the largest
contributing factor to the Em. Organic exposures, were minor during all painting exercises,
except that high isocyanate exposure occurred outside, but not inside, the painter's respirator
during topcoat application inside a comfort pallet (caused by airflow restrictions in the closed
space, and unrelated to the mode of ventilation in the booth). The newly constructed
recirculation duct was a source of several metals. These metals were included in Em
calculations, but the concentrations are expected to decrease after the newly constructed
surfaces are blown clean. Contributions to Em from recirculation are significantly less than the
Air Force criterion of 0.25 imposed by HQ AFLC/SGBE for these tests, and much less, in
IV
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general, than the contribution from the painting process. The painter showed no evidence of
overexposure during the posttest medical evaluation.
G. CONCLUSIONS
Data support the prediction that workplace exposure levels during recirculation of paint
spray booth exhausts, especially combined with split-flow extraction of the pollutant-enriched
lower portion of the exhaust stream, can be maintained less than an arbitrarily selected criterion
(here, Em = 0.25). Flow splitting as a technology is only marginally effective; however, in
combination with recirculation, it acts to lower the concentrations in the recirculated stream at
a given rate of recirculation. Computational projection of Em to larger recirculation rates, and
interpolation of results of an earlier economic analysis of scale-related costs to decontaminate
exhaust air, indicate that available cost savings allow projected payback periods on the order of
1 year for thermal or catalytic incineration.
H. RECOMMENDATIONS
Improvements should be examined to augment or replace present-generation filter and
water paniculate control systems. Concurrently, or when the improved technologies satisfy local
standards, a combination of flow reduction and VOC control should be implemented in an area
of intense regulatory pressure as the definitive prototype. A standardized set of criteria should
be established to guide site selection, design, installation, and maintenance.
v
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PREFACE
This final report was prepared by Acurex Environmental Corporation, 555 Clyde Avenue,
Mountain View, CA 94043, under Contract No. 68-D2-0063, for the U.S. Environmental Protection
Agency (EPA), Air and Energy Engineering Research Laboratory (AEERL), and the Armstrong
Laboratory Environics Directorate (AL/EQ), 139 Barnes Drive, Tyndall Air Force Base (AFB) FL
32403-5323. The industrial hygiene evaluation was performed by Clayton Environmental
Consultants, 1252 Quarry Lake, Pleasanton, CA 94566.
This report describes measurements of background concentrations of airborne toxic
pollutants in Booth 2, Building 845, Travis AFB, CA; design and construction of modifications to
the booth ventilation system; measurements of airborne toxic pollutants in the modified booth
during split-flow and concurrent split-flow and recirculating ventilation; and a projective analysis
of equivalent personnel exposures and net costs to operate flow reduction and emission control
systems at varying recirculation ratios. The work was performed between February 1991 and
September 1992. The Air Force project officer was Dr. Joseph D. Wander. EPA project
managers were Charles H. Darvin and Jamie K. Whitfield.
Indispensable cooperation and support were provided by a number of Air Force functions.
Ted Liston (60 EMS/MAEFP) provided facilities in Building 845 and practical advice; Terry
Kirkbride (60 EMS/MAEFP) and Mark Sandy (60 ABG/EM) managed coordination with cognizant
Travis functions and solicited volunteer painters; Sgt. Bill Fleming and Bill Harrison painted during
the baseline and split-flow tests, respectively; Richard Smith painted during the recirculating
ventilation tests; TSgt. Haugen (DGMC/SGPM) saw to the posttest evaluation of Mr. Smith and
secured his release of the test results; Det 6 AL/SAO, Brooks AFB TX, performed metals and
isocyanate analyses; Major John Seibert, Det 6 AL/EHI and the designee of Col. Bruce Poitrast,
AL/OE-CA, was an active contributor to discussions of baseline data and the test plan for the
recirculation tests; Col. Phil Brown, HQ AFLC/SGBE, accepted responsibility for authorizing the
performance of the recirculation tests, after several iterative discussions of these baseline results
plus data and conclusions from experimental verification of the capability of flame ionization
detector (FID) technology to reliably detect equivalent exposure limit of a complex (specified)
mixture of paint solvents. Major Steve Bakalyar, AL/OEMI, offered constructive suggestions and
contributed to the final version of this document.
VII
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TABLE OF CONTENTS
Section Title Page
I INTRODUCTION 1
A. OBJECTIVE 1
B. BACKGROUND 1
C. SCOPE 1
D. APPROACH 2
II ISSUES, PAST STUDIES, DISCUSSION OF OPTIONS 3
A. ISSUES I.- 3
1. Worker Safety 3
2. Pollution Control Requirements ...' 4
B. PREVIOUS RESEARCH 4
C. FLOW-REDUCTION TECHNIQUES 5
1. Split-flow Ventilation 5
2. Recirculating Ventilation 6
3. Combined Split-flow/Recirculating Ventilation 8
III SITE DESCRIPTION AND MODIFICATION 10
A. SITE DESCRIPTION 10
B. SITE MODIFICATION 10
C. SAFETY PRECAUTIONS 11
IV BASEUNE TEST MATRIX AND RESULTS 13
A. SAMPLING LOCATIONS : 13
B. SAMPLING METHODS 13
1. Organic Compound Sampling 13
2. Paniculate Sampling 16
3. Metals Sampling 16
4. Isocyanate Sampling 17
C. PAINT CONSUMPTION DURING BASELINE TEST SERIES 17
D. AIR FLOW RATE MEASUREMENTS 19
E. RESULTS OF EXHAUST FACE MEASUREMENTS 19
1. Organic Compounds 19
2. Paniculate 20
3. Metals 20
4. Isocyanates . .. 20
ix
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TABLE OF CONTENTS
(CONTINUED)
Section Title Page
F. RESULTS OF EXHAUST DUCT MEASUREMENTS 23
1. Organic Compounds 23
2. Particulate 24
3. Metals 24
4. Isocyanates 25
G. RESULTS OF MEASUREMENTS AT THE PAINTER 25
H. RECIRCULATION AND SPLIT-FLOW CALCULATIONS 25
1. Vertical Distribution 27
2. Position of "Split" 27
V POSTMODIFICATION TEST MATRIX AND RESULTS 34
A. SAMPLING LOCATIONS 34
B. SAMPLING METHODS 34
C. RESULTS OF PAINT CONSUMPTION DURING THE
POSTMODIFICATION TEST SERIES 38
D. AIR FLOW RATE MEASUREMENTS 38
E. RESULTS OF EXHAUST AND INTAKE FACE MEASUREMENTS 45
1. Organic Compounds 45
2. Particulate 49
3. Metals 53
4. Isocyanates 54
F. RESULTS OF DUCT MEASUREMENTS 64
1. Organic Compounds 64
2. Particulate 68
3. Metals . 68
4. Isocyanates 68
G. RESULTS OF MEASUREMENTS AT THE PAINTER 71
1. Organic Compounds 72
2. Particulate 72
3. Metals 72
4. Isocyanates 72
VI INDUSTRIAL HYGJENE EVALUATION 76
A. OBJECTIVE \ 76
B. APPROACH . 76
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TABLE OF CONTENTS
(CONCLUDED)
Section Title Page
C. STANDARDS AND GUIDELINES 77
D. PERSONAL PROTECTIVE EQUIPMENT . 79
E. SAMPLING MATRIX AND METHODS . .'' 80
F. RESULTS OF SAMPLE SET ANALYSIS 80
1. Organics 81
2. Metals 81
3. Isocyanates 83
G. DISCUSSION 83
H. CONCLUSIONS 84
VII ECONOMIC ANALYSES 85
A. CONTROL TECHNOLOGIES 85
B. COSTS OF BOOTH MODIFICATION 85
C. COST ANALYSIS 86
D. PAYBACK PERIOD 86
VIII ENGINEERING CONCLUSIONS AND RECOMMENDATIONS . 90
A. CONCLUSIONS 90
B. IMPLEMENTATION RECOMMENDATIONS 91
C. DESIGN RECOMMENDATIONS 91
1. Steps and Criteria 91
2. Determination of Maximum Attainable Recirculation Ratio 92
REFERENCES 96
APPENDIX A — OSHA RULING ON PAINT BOOTH EXHAUST GAS
RECIRCULATION 99
APPENDIX B — PERMANENT VARIANCE ISSUED BY IOWA FOR A
JOHN DEERE RECIRCULATING PAINT FACILITY 103
APPENDIX C — EXCERPTS FROM AN OSHA INSPECTION REPORT . 108
APPENDIX D — BOOTH MODIFICATION DESIGN AND
CONSTRUCTION PACKAGE In Vol. II
APPENDIX E — ORGANIC DESORPTION STUDY In Vol. II
APPENDIX F — REDUCED DATA FOR THE BASELINE TEST
SERIES : In Vol. II
APPENDIX G — REDUCED DATA FOR THE POSTMODIFICATION
TEST SERIES In Vol. II
APPENDIX H — QUALITY ASSURANCE/QUALITY CONTROL
EVALUATION In Vol. II
APPENDIX I — ECONOMIC CALCULATIONS In Vol. II
APPENDIX J — EXAMPLE CALCULATION WORKSHEET FOR
PERCENT RECIRCULATION VERSUS PERCENT
PARTICULATE REMOVAL EFFICIENCY In Vol. II
xi
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LIST OF FIGURES
Figure Title Page
1 Schematic Diagram of a Split-Flow Ventilation System 6
2 Schematic Diagram of a Paint Spray Booth Recirculating
Ventilation System 7
3 Schematic Diagram of a Paint Spray Booth Ventilation System Combining
Split-Flow and Recirculating Ventilation 9
4 Schematic Diagram of Original Paint Spray Booth 2 Configuration 11
5 Schematic Diagram of Modified Paint Spray Booth 2 12
6 Sampling Locations for Baseline Test Series 14
7 Sampling Locations at the Exhaust Face of Booth 2 at Travis AFB 14
8 Results of Organic Measurements at the Exhaust Face During Baseline
Testing 21
9 Measured Concentrations of Particulate at the Exhaust Face During
Baseline Testing . 21
10 Concentrations of Strontium Chromate Measured at the Exhaust Face ... 22
11 Baseline HDI Concentrations Measured at the Exhaust Face 22
12 Vertical Distribution of Paint Constituents at the Exhaust Face 28
13 Intake Em Versus Split Height 31
14 Sampling Locations for the Postmodification Test Series 37
15 Sampling Locations at One of Two Intake Faces 37
16 Results of Organic Measurements at the Intake and Exhaust Faces During
Split-flow/Recirculating Ventilation—Test 1 46
17 Results of Organic Measurements at the Intake and Exhaust Faces During
Split-flow/Recirculating Ventilation—Test 2 46
18 Results of Organic Measurements at the Intake and Exhaust Faces During
Split-flow/Recirculating Ventilation—Test 3 47
19 Results of Organic Measurements at the Intake and Exhaust Faces During
Split-flow/Recirculating Ventilation—Test 4 47
xii
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LIST OF FIGURES
(CONTINUED)
Figure Title Page
20 Results of Organic Measurements at the Intake and Exhaust Faces During
. Split-flow/Recirculating Ventilation—Test 5 48
21 Results of Organic Measurements at the Intake and Exhaust Faces During
Split-flow/Recirculating Ventilation—Test 6 48
22 Results of Organic Measurements at the Intake and Exhaust Faces During
Split-flow Ventilation—Test 1 49
23 Measured Concentrations of Paniculate at the Intake and Exhaust Faces
During Split-flow/Recirculating Ventilation—Test 1 50
24 Measured Concentrations of Paniculate at the Intake and Exhaust Faces
During Split-flow/Recirculating Ventilation—Test 2 50
25 Measured Concentrations of Paniculate at the Intake and Exhaust Faces
During Split-flow/Recirculating Ventilation—Test 3 51
26 Measured Concentrations of Paniculate at the Intake and Exhaust Faces
During Split-flow/Recirculating Ventilation—Test 4 51
27 Measured Concentrations of Paniculate at the Intake and Exhaust Faces
During Split-flow/Recirculating Ventilation—Test 5 5.. 52
28 Measured Concentrations of Paniculate at the Intake and Exhaust Faces
During Split-flow Ventilation—Test 1 52
29 Measured Concentrations of Paniculate at the Intake and Exhaust Faces
During Split-flow Ventilation—Test 2 53
30 Concentrations of Strontium Chromate Measured at the Intake and Exhaust
Faces—Test 1 : 55
31 Concentrations of Strontium Chromate Measured at the Intake and Exhaust
Faces—Test 2 55
32 Concentrations of Strontium Chromate Measured at the Intake and Exhaust
Faces—Test 3 56
33 Concentrations of Strontium Chromate Measured at the Intake and Exhaust
Faces—Test 4 56
34 Concentrations of Strontium Chromate Measured at the Intake and Exhaust
Faces—Test 5 57
xiii
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LIST OF FIGURES
(CONCLUDED)
Figure Title Page
35 Concentrations of Lead at the Intake and Exhaust Faces—Test 1 57
36 Concentrations of Lead at the Intake and Exhaust Faces—Test 2 58
37 Concentrations of Lead at the Intake and Exhaust Faces—Test 3 58
38 Concentrations of Lead at the Intake and Exhaust Faces—Test 4 59
39 Concentrations of Lead at the Intake and Exhaust Faces—Test 5 59
40 Concentrations of Zinc at the Intake and Exhaust Faces—Test 1 60
41 Concentrations of Zinc at the Intake and Exhaust Faces—Test 2 60
42 Concentrations of Zinc at the Intake and Exhaust Faces—Test 3 61
43 Concentrations of Zinc at the Intake and Exhaust Faces—Test 4 61
44 Concentrations of Zinc at the Intake and Exhaust Faces—Test 5 62
45 Concentrations of HDI Measured at the Intake and Exhaust Faces—Test 1 . 62
46 Concentrations of HDI Measured at the Intake and Exhaust Faces—Test 2 . 63
47 Concentrations of HDI Measured at the Intake and Exhaust Faces—Test 3 . 63
48 Concentrations of HDI Measured at the Intake and Exhaust Faces—Test 4 . 64
49 Representative Results from Continuous Emission Monitoring by EPA
Method 25A—Topcoat Painting 66
50 Representative Results from Continuous Emission Monitoring by EPA
Method 25A—Primer Painting 66
51 Representative Results from Continuous Emission Monitoring by EPA
Method 25A-Split-flow Test 67
52 Capital Costs for Incineration as a Function of Exhaust Flow Rate 88
53 Annual Operating Costs for Incineration as a Function of
Exhaust Flow Rate 88
54 Total Emission Control Costs for Incineration Over 10 Years 89
55 Dependence of Maximum Projected Recirculation on Percent Particulate
Removal Efficiency — Recirculating Ventilation 94
XIV
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LIST OF TABLES
Table Title Page
1 SAMPLING MATRIX FOR BASELINE TEST SERIES 15
2 ORGANIC SPECIES TARGETED FOR NIOSH METHOD 1300 ANALYSIS.. 16
3 RESULTS OF PAINT DENSITY AND PERCENT VOLATILE ANALYSES ... 17
4 PAINT CONSUMPTION RATES DURING BASELINE TEST SERIES 18
5 FLOW RATES MEASURED IN THE EXHAUST DUCT DURING THE
BASELINE TEST SERIES 19
6 CONCENTRATIONS OF ORGANIC COMPOUNDS MEASURED IN THE
EXHAUST DUCT 23
7 CONCENTRATIONS OF PARTICULATE MATTER MEASURED IN THE
EXHAUST DUCT 24
8 CONCENTRATIONS OF METAL COMPOUNDS MEASURED IN THE
EXHAUST DUCT 25
9 CONCENTRATIONS OF ISOCYANATE COMPOUNDS MEASURED IN THE
EXHAUST DUCT 26
•
10 CONCENTRATIONS OF AIR POLLUTANTS OUTSIDE AND INSIDE THE
PAINTER'S RESPIRATOR HOOD 26
11 MAXIMUM CONCENTRATIONS OF POLLUTANTS MEASURED IN THE
EXHAUST DUCT DURING THE BASELINE TEST SERIES 30
12 Em AT THE INTAKE OF A SPLIT-FLOW/RECIRCULATING VENTILATION
PAINT SPRAY BOOTH, ASSUMING 40-PERCENT RECIRCULATION AND
8 HOURS OF EXPOSURE PER DAY 32
13 Em AT THE INTAKE OF A SPLIT-FLOW/RECIRCULATING VENTILATION
PAINT SPRAY BOOTH, ASSUMING 40-PERCENT RECIRCULATION
AND 2 HOURS OF EXPOSURE PER DAY 33
14 SAMPLING MATRIX FOR SPLIT-FLOW/RECIRCULATING VENTILATION
TESTS 35
15 SAMPLING MATRIX FOR SPLIT-FLOW TESTS 36
16 RESULTS OF PAINT DENSITY AND PERCENT VOLATILE ANALYSES ... 39
xv
-------
LIST OF TABLES
(CONTINUED)
Table Title Page
17 PAINT CONSUMPTION RATES DURING POSTMODIFICATION
TEST SERIES 40
18 VOLUMETRIC FLOW RATES AT INTAKE FACES, SPLIT-FLOW DUCT, AND
RECIRCULATION DUCT 44
19 AVERAGE CONCENTRATIONS OF TOTAL ORGANIC SPECIES MEASURED
IN THE SPLIT-FLOW AND RECIRCULATION DUCTS USING NIOSH
METHOD 1300 . . 65
20 SOLVENT MASS BALANCE RESULTS 69
21 CONCENTRATIONS OF PARTICULATE MEASURED IN THE SPLIT-FLOW
AND RECIRCULATION DUCTS 70
22 CONCENTRATIONS OF METALS MEASURED IN THE SPLIT-FLOW AND
RECIRCULATION DUCTS 71
23 CONCENTRATIONS OF HDI IN THE SPLIT-FLOW AND RECIRCULATION
DUCTS 71
24 CONCENTRATIONS OF ORGANICS OUTSIDE THE PAINTER'S
RESPIRATOR 73
25 CONCENTRATIONS' OF ORGANICS INSIDE THE PAINTER'S
RESPIRATOR 73
26 PARTICULATE CONCENTRATIONS MEASURED IN THE VICINITY OF THE
PAINTER j 74
27 CONCENTRATIONS OF METALS OUTSIDE THE PAINTER'S
RESPIRATOR 74
28 CONCENTRATIONS OF METALS INSIDE THE PAINTER'S
RESPIRATOR 75
29 CONCENTRATIONS OF HDI AT THE PAINTER'S BREATHING ZONE 75
30 OSHA PELs AND ACGIH TLVs FOR TARGET COMPOUNDS
(8-HOUR TWA) 78
31 AIR SAMPLING MATRIX 80
xvi
-------
LIST OF TABLES
(CONCLUDED)
Table Title Page
32 POSTMODIFICATION AIR SAMPLING (8-HOUR TWA) RESULTS AND Em
FOR ORGANICS 82
33 METALS BASELINE AIR CONCENTRATIONS (8-HOUR TWA) 82
34 POSTMODIFICATION AIR SAMPLING (8-HOUR TWA) RESULTS AND Em
FOR METALS 83
35 EMISSION STREAM ASSUMPTIONS FOR ECONOMIC ANALYSIS 87
36 CAPITAL, OPERATING, AND LIFETIME COSTS FOR THERMAL
INCINERATION 87
37 CAPITAL, OPERATING, AND LIFETIME COSTS FOR CATALYTIC
INCINERATION 87
38 PAYBACK PERIODS FOR MODIFYING THE BOOTH FLOW TO COMBINED
SPLIT-FLOW/RECIRCULATING VENTILATION 89
XVII
(The reverse of this page is blank)
-------
LIST OF ABBREVIATIONS, ACRONYMS, AND SYMBOLS
a Fraction of pollutants found below the split height
A Area
ACGIH American Conference of Governmental Industrial Hygienists
AEERL U.S. EPA Air and Energy Engineering Research Laboratory
AFB Air Force Base
APCD Air Pollution Control District
ASA Analysis safety alarm
ASE Analysis safety element
AST Analysis safety transmitter
ASV Analysis safety valve
BAAQMD Bay Area Air Quality Management District
BACT Best Available Control Technology
Btu British thermal unit
C Booth concentration '
CEM Continuous emissions monitoring
cfm Cubic feet per minute
CFR Code of Federal Regulations
Dl Deionized (water)
DQO Data quality objective
dscfm Dry standard cubic feet per minute
EM Environmental Management
Em Equivalent exposure for a mixture of air contaminants, scaled in multiples of the
permissible 8-hour time-weighted average
EPA U.S. Environmental Protection Agency
FID Flame ionization detector
fpm Feet per minute
HDI Hexamethylene diisocyanate
kg Kilograms
MACT Maximum Achievable Control Technology
MDI Methylene diphenyl diisocyanate
MEK Methyl ethyl ketone
MIBK Methyl isobutyl ketone
XIX
-------
MSDS Material Safety Data Sheet
NA Not applicable
N.A. Not available
(NA) Not analyzed
NO Not detected
NM Not measured
NFPA National Fire Protection Agency
NIOSH National Institute of Occupational Safety and Health
OAQPS U.S. EPA Office of Air Quality Planning and Standards
OSHA Occupational Safety and Health Administration
PEL Permissible exposure limit
PF Protection factor for respiratory equipment
PGMEA Propylene glycol monoethyl ether acetate
ppmv Parts per million volume
Q Flow rate
QA Quality assurance
QC Quality control
QEC Quick engine change
R Recirculation ratio
RACT Reasonably Available Control Technology
RPD Relative present difference
RTI Research Triangle Institute
scf Standard cubic feet
scfm Standard dry cubic feet per minute
STEL Short-term exposure limit
TDI Toluene-2,4-diisocyanate
TLV Threshold limit value
TOG Total organic carbon
TUHC Total unburned hydrodarbon
v Velocity
VOC Volatile organic compound
Subscript
b Bottom section of exhaust plenum
fresh Fresh air stream
xx
-------
/ Component /
in Intake
intake Intake stream
recirc Recirculated air stream
t Top section of exhaust plenum
unmod Unmodified, single pass flow conditions
xxi
-------
METRIC CONVERSION TABLE.
English
SI
SI Symbol
To Convert from
English to SI, Multiply
By
Area
Square inch
Square foot
Square centimeter
Square meter
cm2
m2
6.452
0.09290
Length
Inch
Foot
Centimeter
Meter
cm
m
2.54
0.3048
Volume
Cubic inch
Cubic foot
Cubic centimeter
Cubic meter
cm3
m3
16.387
0.02832
Mass
Pound mass
Kilogram
kg
0.4536
Work, Energy, Heat
Btu
Btu
Kilowatt-hour
Joule
Kilowatt-hour
Kilojoule
J
kWh
kJ
1055
0.000293
3600
Power, Heat Rate
Horsepower
Btu/hour
Watt
Watt
W
W
745.7
0.2931
Temperature
Fahrenheit
Celsius
°C
5/9(°F-32)
Flow Rate
Cubic foot/minute
Cubic meter/second
m3/s
0.0004719
XX.1 i
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SECTION I
INTRODUCTION
A. OBJECTIVE
The objective of this program was to demonstrate that split-flow and recirculating
ventilation, individually and in combination, are safe and cost-effective methods to reduce paint
spray booth exhaust flow rates and to lower the costs both of conditioning intake air and of
controlling volatile organic compound (VOC) emissions in exhaust air.
B. BACKGROUND
The U.S. Air Force, in a joint effort with the U.S. Environmental Protection Agency (EPA),
is conducting an extensive research program to develop cost-effective methods of controlling
VOC emissions from Air Force spray painting operations. This study was part of an extended
program of investigations into the cost and efficacy of innovative approaches for bringing Air
Force industrial operations into compliance with current and anticipated air pollution
environmental standards. The specific operation of interest in this study was aircraft-related
equipment painting, in which solvent-based epoxy primers and solvent-based polyurethane
topcoats are used. Some of these Air Force coatings, although approved for corrosion control,
exceed the current established limits for VOC content. These limits were established by the EPA,
and by state and local regulatory agencies, to achieve compliance with the Clean Air Act.
Adequate ventilation of paint spray booths requires movement of large quantities of air,
which are slightly contaminated during passage through the booth. Air exhausted from this
process requires decontamination, which, although technically achievable at operating flow rates,
can be prohibitively expensive. Because emission-control costs depend on the volume of air
being treated, considerable savings can be realized by applying an acceptable flow-reduction
method.
Results from previous EPA and Air Force joint studies indicate that airborne toxic
pollutants concentrate in the lower regions of cross-flow paint spray booths. This finding led to
the development of three cost-saving strategies for paint spray booth ventilation: split-flow
ventilation, recirculating ventilation, and combined split-flow/recirculating ventilation.
C. SCOPE
Two flow-reduction strategies were tested in this project: split-flow ventilation and
combined split-flow/recirculating ventilation. Test data were used to project the impact of
different recirculation ratios, both with and without split-flow ventilation. The flow-reduction
strategies were evaluated based on worker safety and economic criteria. The project also
experimentally evaluated the feasibility of using an automated ventilation control system that
continuously monitors VOC concentrations in the recirculated airstream (as required by National
Fire Protection Agency [NFPA] codes) to ensure against inadvertent overexposure of personnel
working in the booth.
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D. APPROACH
To achieve the project objective, two test series were conducted: baseline, and
combined split-flow/recirculating ventilation. The baseline test series characterized the
distribution of toxic pollutants at the exhaust face and in the exhaust duct of Booth 2. These
results were used to locate the split position and the recirculation rate for the split-
flow/recirculating ventilation test series. These data and the test plan for the second set of tests
were reviewed by HQ AFLC/SGBE before approval was given to proceed with the recirculation
tests.
Prior to the second test series, the ductwork in Booth 2 was reconfigured to separate
exhaust streams from the top and bottom of the booth (split-flow) and to return the upper
exhaust stream to the intake plenum for recirculation through the booth. The
split-flow/recirculating ventilation test series demonstrated the feasibility of flow reduction to
enhance the economics of VOC emission control. During this test series, several split-flow tests
were also conducted to verify that split-flow ventilation by itself improves the economics of VOC
emission control, and that the ventilation system was designed correctly. The results of the split-
flow/recirculating ventilation and split-flow tests were also used to evaluate the impact of
recirculation on pollutant concentration profiles in the booth.
For the baseline and split-flow/recirculating ventilation test series, comprehensive
sampling and analysis matrices were developed. Each test matrix included sampling in the
ventilation ducts and in the booth at the exhaust face to measure concentrations of VOCs,
paniculate, metals, and isocyanates. In-booth sampling identified constituent concentration
profiles at the exhaust face during painting as well as concentrations in the vicinity of the painter.
Duct sampling yielded constituent concentrations in the ventilation streams. Such engineering
parameters as temperature, pressure, and flow rates were also measured.
The purpose of the test program was to determine the effectiveness of the split-flow and
recirculation modifications in typical Air Force painting operations; it was a proof-of-concept study
only. It is recognized that the concentration gradients that occur during painting depend on both
the flow parameters of the ventilation system, and the size and orientation of the object painted.
In general, small workpieces (less than 5 feet high) are painted at the Air Force facility targeted
for conversion. Previous studies have demonstrated that, under these conditions, favorable
concentration gradients occur.
Each activity conducted at Travis AFB depended upon approval prior to the start of the
activity. Details of proposed activities were sent to Travis AFB and the base Environmental
Management (EM) Office, to expedite approval by the respective fire, safety, and
bioenvironmental engineering authorities before commencement of booth testing or modification
activities. In addition, the test plan was reviewed and approved by HQ AFLC/SGBE.
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SECTION II
ISSUES, PAST STUDIES, DISCUSSION OF OPTIONS
This section describes the issues, past studies, and available options pertaining to flow-
reduction strategies.
A. ISSUES
Worker safety and air pollution control issues are discussed below as they pertain to flow
reduction strategies.
1. Worker Safety
Until recently, the Occupational Safety and Health Administration (OSHA) prohibited
the use of recirculation as a means of lowering VOC emission control costs associated with paint
spray booths.
The OSHA regulation 29 CFR (Code of Federal Regulations) 1910.107 (d) (9)
(Reference 1) states the following:
Air exhaust from spray operations shall not be directed so that it will contaminate
makeup air being introduced into the spraying area or other ventilating intakes,
nor directed so as to create a nuisance. Air exhausted from spray operations
shall not be recirculated.
This regulation was developed from NFPA Code 33-1969, which is explicitly a fire and explosion
safety standard. Subsequent amendments to NFPA Code 1969, adopted in 1985, permit
recirculation with adequate monitoring and warning systems installed in the booth.
In December 1989, after consultations with the EPA-AEERL and Office of Air Quality
Planning and Standards (OAQPS), OSHA issued a ruling that recirculation may be used in paint
booths as long as the air quality in the booth complies, at a minimum, with the requirements
identified in 29 CFR 1910.1000, which establishes permissible exposure limits (PELs). A copy
of the letter affirming this allowance is provided in Appendix A. Successful industrial applications
have also been accomplished; an example of a permanent variance is reproduced in
Appendix B. An example of OSHA's treatment of recirculating facilities is reproduced in
Appendix C, a citation for unrelated violations in a recirculating facility.
The PELs are listed in 29 CFR 1910.1000 for various compounds (Reference 1). In
addition, it also presents the following equation for calculating the equivalent PEL for a mixture
of air contaminants exhibiting a common mode of toxicity:
Em
where:
-------
Em = The equivalent exposure for the mixture
C, = The concentration of contaminant /
L, = The PEL for substance / as specified in Subpart Z of 29 CFR Part 1910
An £m value greater than unity (1.0) implies that the toxicity level exceeds the exposure limit
during an 8-hour work shift of a 40-hour workweek. An Em less than unity implies that the
equivalent exposure for the air mixture is within acceptable worker exposure limits.
2. Pollution Control Requirements
The Clean Air Act Amendments of 1990 will have a substantial impact on aerospace
coating facilities. In particular, Title III of the 1990 Amendments establishes a list of 189 federally-
regulated hazardous air pollutants (HAPs). The Amendments direct the EPA to promulgate
emissions standards for each category of major and area sources of HAPs; the emission
standards for surface coatings in the aerospace industry are due by November 15, 1994.
Compliance dates for existing sources will be within 3 years of each standard's effective date
(Section 112(i)(3)(B)). Section 112(d) requires these standards, referred to as Maximum
Achievable Control Technology (MACT), to achieve the maximum degree of reduction in HAP
emissions. MACT standards must take into account the cost of emissions reductions, non-air
quality health and environmental impacts, and energy requirements. For existing sources, the
MACT emission standards must be at least as stringent as the average emissions limitation of
the best 12 percent of existing sources (Section 112(a)(10)).
Currently, thermal and catalytic incineration and adsorption are three commonly used
controls in surface coating operations. If these or any other types of add-on control device are
required by the MACT standards, the capital and operating costs will be significant given the large
flow rates used in aerospace coating facilities. These costs can be significantly decreased
through the use of flow reduction strategies, which decrease the flow rate through the control
device, thereby decreasing the control device size (see Section VII). Thus, EPA MACT
requirements may, in effect, result in the implementation of recirculating ventilation in paintbooths
as an economically feasible option to obtain compliance.
B. PREVIOUS RESEARCH
Emissions from paint spray booths at several Air Force test sites will not comply with
future regional air pollution control district (APCD) regulations unless the emission levels are
lowered. Installing a VOC emission control device downstream of a booth exhaust is a technically
effective method of achieving a high degree of VOC emission control. However, the associated
capital, installation, and operating costs can be high, because the control device must be sized
sufficiently large to process the large volumetric air flow and the low solvent concentrations
associated with paint spray booth emissions (Reference 2).
Recent studies by the EPA and Air Force indicate that the cost of VOC emission control
is significantly decreased by reducing the paint spray booth exhaust flow rate to a downstream
emission control device. A 1988 study suggested that recirculation of paint spray booth exhaust,
accompanied by a VOC control device, is an effective flow-enhancement method of achieving
cost-effective VOC emission control (Reference 3). This method of flow reduction is referred to
as recirculating ventilation.
-------
To implement this flow-reduction concept, it must first be established that recirculation
does not cause an accumulation of toxic compounds in the booth (which would create unsafe
working conditions). To confirm this contention, the spatial" distribution of VOC, paniculate,
metal, and isocyanate species was measured during typical operations in a working paint spray
booth at Hill AFB, Utah (Reference 4). The study found that low concentrations occur throughout
most of the booth during normal operation, except that the toxic compounds tended to
concentrate toward the lower regions of the booth and immediately in front of the painter. A
flow-reduction ventilation system taking advantage of this phenomenon was designed, in which
the plenum chamber located behind the exhaust face is modified to accommodate two exhaust
ducts. This is referred to as split-flow ventilation (Reference 5).
C. FLOW-REDUCTION TECHNIQUES
%
Three flow-reduction techniques are described in the subsections that follow: split-flow
ventilation, recirculating ventilation, and combined split-flow/recirculating ventilation.
1. Split-flow Ventilation
A split-flow ventilation system (patent pending) (Reference 5) takes advantage of the '
constituent concentration gradients that naturally occur in most painting operations. A split-flow
duct segregates the exhaust plenum into two streams: the air stream with the larger solvent
concentration, which is exhausted to a VOC emission control device, and the second air stream,
which is vented through a second plenum section to the outside.
Figure 1 is a schematic diagram illustrating the split-flow ventilation concept. The
concentration gradient is determined by height and direction of paint application. If the
concentration in the top portion is sufficiently low, the air stream from the upper zone may be
discharged without treatment. As shown in the figure, 75 percent of the pollutants released are
contained within the bottom half of the exhaust plenum, and the remaining 25 percent in the top
half. In such a case, the VOC mass exhausted to a VOC emission control system is indicated
by the shaded portion of the figure.
The advantage of this system is that the flow rate to the VOC emission control device
is reduced, and, accordingly, the size of the control device can be reduced, resulting in a
reduction in control system capital and operating costs. The reduction in flow rate is directly
related to the ratio of the height of the split position to the total booth height. The primary
limitation of the split-flow system is that 100-percent emission control is not achievable.
To determine the concentration of pollutants in the upper exhaust plenum, a mass
balance for the booth can be developed. Assuming that steady-state and well-mixed conditions
prevail inside the booth, and that the fresh intake air is pollutant-free, the mass balance for split-
flow ventilation will be as follows:
generation rate = exhaust rate
Cunn^O = CbQb + CtQt (2)
where:
-------
EXHAUST
FRESH
AIR
TO
TREATMENT
[C]
Figure 1. Schematic Diagram of a Split-Flow Ventilation System.
Cunmod = Concentration in unmodified booth
Q = Total booth flow rate
Cb = Concentration in bottom section of exhaust plenum
Qb = Flow rate out bottom section of exhaust plenum
Ct = Concentration in top section of exhaust plenum
Qt = Flow rate out top section of exhaust plenum
Defining a as the fraction of pollutants that are found below the split height,
a =
Q/A
(3)
and solving for the concentration exhausted out the top portion of the plenum,
Ct
(1 - a)
a,
(4)
2. Recirculating Ventilation
A simple way to reduce the process flow rate to a VOC emission control device is to
install a return air flow system, which recirculates filtered exhaust air back into the booth.
Figure 2 is a schematic diagram illustrating a typical recirculating ventilation system. A
recirculating ventilation system removes a portion of the booth exhaust through a bleed-off duct
and vents to an emission control device. The remainder of the exhaust passes back into the
booth through a recirculation duct installed on the exhaust plenum. Prior to reentering the paint
-------
i FRESH
-^ . (MAKEUP)
TO
TREATMENT
EFFICIENT MIXING
OCCURS THROUGH FANS
PARTICULATE
FILTERS
unmod
Figure 2. Schematic Diagram of a Paint Spray Booth Recirculating Ventilation System.
spray booth, the recirculated air is mixed with fresh air (brought in to replace the bleed-off air)
in an intake plenum.
The advantage of the recirculation system is that it significantly reduces the exhaust
flow volume, yet achieves the maximum level of VOC emission control. This decrease in exhaust
flow rate reduces the capital and operating costs of a VOC emission control system because the
control device capacity is determined by the bleed-off flow rate.
The Hill AFB study found that the concentrations in the vicinity of the painter are
greater than the overall booth concentrations. This is due to localized perturbations in the airflow
and paint gun overspray patterns, not to booth ventilation patterns. As discussed in Section VI,
the increase in pollutant concentrations in the vicinity of the painter, from recirculation, is
negligible in comparison to the job-intrinsic exposures.
A mass balance can be performed to determine the concentrations in the upper
plenum that are recirculated into the booth. To develop the mass balance analysis for
recirculating ventilation, steady-state, well-mixed flow conditions (Ct = C£ are assumed. As for
the split-flow mass balance, the mass generated equals the mass exhausted from the booth:
= CbQb
(5)
where Cunmod is the concentration in the unmodified booth (therefore Cunmod £ C£. Because,
Q = (0,,+ Qt)
(6)
-------
substitution yields
Ounn^O. - Qt) = CbQb (7)
Defining /?, the recirculation ratio, as
R -- !— (8)
(Q, + O*)
then,
This relationship is plotted in the graph accompanying Figure 2.
3. Combined Split-flow/Recirculating Ventilation
Significant benefits are derived from a flow-reduction system combining the
recirculation and split-flow strategies, in which the split-flow exhaust air containing low constituent
concentrations is recirculated back into the booth after mixing with fresh make-up air. The
combined system achieves the maximum attainable control of VOC emissions, and decreases
the constituent concentration in the recirculation stream to the lowest possible level for safe
recirculation.
Figure 3 is a schematic diagram illustrating a combined split-flow/recirculating
ventilation system. The circle "A" in the figure represents a VOC concentration monitor installed
to ensure the painter's safety. The paint overspray pattern and target configuration determine
the concentration in the recirculation stream.
A mass balance is performed to calculate the concentration recirculated into the
booth intake from the upper exhaust plenum. For steady-state conditions, the mass balance for
combined split-flow/recirculating ventilation is as follows:
C^^ = C^Q. - 0.) = CbQb (10)
Furthermore,
a
(1 - a) QtCt
Substitution gives
8
(11)
-------
FRESH
AIR
9
!
^p
r^ L-
F
^F^
%.—
-*- TO
TREATMENT
Figure 3. Schematic Diagram of a Paint Spray Booth Ventilation System
Combining Split-Flow and Recirculating Ventilation.
Of)
QtCta
0 -a)
(12)
and using the definition of R, and solving for Ct gives
I -
(13)
-------
SECTION III
SITE DESCRIPTION AND MODIFICATION
A. SITE DESCRIPTION
Paint Spray Booth 2, Building 845, Travis Air Force Base, California, was the site selected
for this airflow modification study. The interior of the booth is 25.75 feet long, 18 feet wide, and
14 feet high. It has a crossdraft ventilation system in which fresh air is introduced into the booth
through a fiberglass mesh filter system at the side wall front edges. The air exits the rear of the
booth through a pleated-paper/fiberglass mesh filter that completely covers the exhaust plenum.
Prior to Booth 2's modification, its entire exhaust was vented to the atmosphere through a 48-
inch-diameter duct located on top of the exhaust plenum. The booth is maintained under
negative pressure to prevent solvent emissions into the surrounding work areas of Building 845.
Figure 4 is a schematic diagram of the booth prior to modification.
The booth operators used conventional, high-pressure, high-volume paint spray guns.
The flow rate in the booth was typically maintained at 30,000 cfm, for a face velocity of 120 fpm.
B. SITE MODIFICATION
As discussed in Section I, two flow-reduction strategies were tested. The booth was
modified to permit both split-flow and combined split-flow/recirculating ventilation. The flow-
reduction design incorporated most of the existing equipment, including fans and ductwork.
Because the booth operated on a light schedule, booth downtime during modification did not
affect Air Force operations. The total modification time was less than 1 month. The design
package for the booth modification is presented in Volume II, Appendix D.
The modification accommodated split-flow ventilation and combined split-
flow/recirculating ventilation. For the test program, a physical division was established between
the upper and lower plenums to maintain a known, consistent stream-split height. Prior to
modification, the baseline test series was conducted. Based on the results (Section IV), the split-
height of 7.5 feet was selected to produce an approximate exhausted/recirculated flow-volume
split of 54/46. A sheet metal transition piece, 7.5 feet high and as wide as the booth, was
installed on the floor of the existing plenum and set tight against the back of the exhaust filter
media. This transition piece was connected to the new exhaust duct and exhaust blower. The
creation of a new enclosed plenum required the installation of a fire suppression system with
associated piping, electrical, and alarm connections. The upper chamber vented to the existing
atmospheric exhaust duct.
In this test, a physical barrier was used to separate the exhaust and recirculated streams
to ensure absolute certainty about the split-stream height and the relative flow volumes.
However, a split-stream configuration could have been achieved without a physical division
between the upper and lower plenums. By providing a blower with a lower duct located at or
near the floor of the existing plenum, and a second blower at the upper duct (recirculating or
exhausting air to atmosphere), the existing exhaust flow could be separated. The ratio of air
exhausted to the upper and lower regions would be proportional to the force of the two blowers.
In this case, the pollutant-rich stream, normally concentrated in the lower half of the paint booth,
would remain in the lower half as it exited the booth through the exhaust duct located near the
10
-------
Figure 4. Schematic Diagram of Original Paint Spray Booth 2 Configuration.
floor. The duct towards the roof of the plenum would collect the remaining, relatively clean
exhaust stream.
In the combined split-flow/recirculating ventilation configuration of the paint booth, the
lower duct vented the pollutant-rich stream to the outside. The stream with lower solvent
concentrations passed through the rerouted upper-chamber exhaust duct. This upper duct,
modified with new ducting and two dampers, passed from the upper exhaust plenum chamber
over the paint booth roof to the existing intake plenum. In this plenum, the recirculated air was
mixed with fresh air, which was brought in to replace the air bled off by the new exhaust blower.
An intake fan drew this mixed air into the intake plenum and through the intake filters into the
booth.
The system design modifications were developed based on the baseline test series
results. No modification to the intake face was required because a sealed intake plenum already
existed. Figure 5 is a schematic diagram of the booth after modification.
C.
SAFETY PRECAUTIONS
Special safety procedures were followed to prevent accidental overexposure of personnel
in the booth. During painting operations, the painter wore a positive-pressure airline respirator
and a fully enclosed suit. Therefore, a transient increase in pollutant concentrations in the booth
did not pose any increased health risk.
As an additional safety measure, the VOC concentration in the recirculated stream was
continuously monitored upstream of the intake face during the combined split-flow/recirculating
ventilation test series. To ensure painter safety, the monitor was attached to an automatic
11
-------
Figure 5. Schematic Diagram of Modified Paint Spray Booth 2.
control system that converted the booth to conventional single-pass operation if the measured
VOC concentration exceeded predetermined concentration setpoints. Two setpoints were
established: an instantaneous concentration setpoint, and a 60-second average concentration
setpoint. The instantaneous setpoint was defined as 350 ppm, the calculated short-term
exposure limit (STEL) for a typical paint mixture (Reference 6). The 60-second average setpoint
was set at 320 ppm. The intake concentration was monitored with an FID. Research was
conducted at the Research Triangle Institute (RTI) to determine the FID response for a mixture
of solvents at the STEL (Reference 6). Whenever either setpoint was exceeded, the booth
converted automatically to single-pass operation, quickly expelling the entire booth volume.
Conservative by common workplace standards, these exposure controls—personal
respiratory equipment, safety suits, and fail-safe conversion out of recirculation configuration —
minimized worker safety risks during this test series.
During recirculating ventilation tests, the inlet air heater, an open-flame model, was shut
off for safety and emission monitoring reasons. If the inlet air must be heated, another type of
heater should be installed, preferably an electric heater located upstream of the mixing point of
the recirculation and fresh air streams. Open-flame heaters may create a fire or oxygen depletion
hazard in recirculating ventilation designs.
12
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SECTION IV
BASEUNE TEST MATRIX AND RESULTS
A 1-week baseline test series was conducted during April 1991 to characterize unmodified
paint spray booth operations and emissions, using Booth 2 as the test site. The objective of the
test series was to obtain sufficient data to determine the vertical distribution of pollutants in the
booth and determine a conservative split height for the split-flow/recirculating ventilation booth
modifications. The data were also used to calculate equivalent exposure levels in the vicinity of
the painter that are compared with the postmodification equivalent exposure results in Section VI
to determine the practicability of flow modifications.
A. SAMPLING LOCATIONS
Figure 6 shows the sampling locations for the baseline test series. These locations
included the booth exhaust face (Site B), the exhaust duct (Site C), and inside and outside the
painter's airline respirator hood (Site A). At the exhaust face, data were collected at 24 sampling
locations, as shown in Figure 7.
B. SAMPLING METHODS
The baseline test matrix and analytical methods used are summarized in Table 1. Four
pollutant categories—paniculate, organics, isocyanates, and metals—were selected for sampling,
for the following reasons:
• Organic species are primary constituents of virtually all Air Force
coatings.
• Paniculate matter is released from spray-painting operations.
• Metals, such as strontium chromate, lead, and zinc, are found in many
coatings, especially primers.
• Isocyanates are found in polyurethane topcoats.
For each pollutant category, two 1- to 1.5-hour sampling events were conducted. Eight sampling
events, in total, were conducted over a 1-week period. With the exception of NIOSH
Method 1300, all sampling and analytical procedures were as specified in the respective methods
used. Justification for the sampling and analytical methods employed is provided in
Subsections 1 through 4 that follow.
1. Organic Compound Sampling
NIOSH Method 1300 was used for organic-compound sampling. In this test series,
the method was modified based on results from previous military paint spray booth testing
events. Larger charcoal tubes than required by NIOSH Method 1300 were used. The use of
these larger tubes consistently resulted in sufficient sample collected with minimum solvent
breakthrough. The extraction solvent was modified specifically for use in desorbing solvents
used in military paints from charcoal sampling tubes. The laboratory desorption study conducted
in support of the solvent modification is provided in Volume II, Appendix E.
13
-------
B
EXHAUST DUCT
Figure 6. Sampling Locations for Baseline Test Series.
12"
18" .
36"
I
36"
36"
1
is- ;
:
5 6
S&S&S^S&S&ft&Sfiifi^SfifiAfififtflS&S&S&S&S&SfififififiS
•••!•
• 13 • 14
• 21 • 22
•^^•H
HIHnHI
V^-T <_ *
1
v^
I
V
7 8
Tfiftfifififififi£5AfiftSfiSfifiSfifififififi&5&5fi£5£5A2SSfifi£Sfl£5£W
<
1
1 12
• 15 «16
• 23 • 24
•^^•H
I^^Rv^^M
-• ^ji" b
.— O7",^
^ £.1 ^
Figure 7. Sampling Locations at the Exhaust Face of Booth 2 at Travis AFB.
14
-------
TABLE 1. SAMPLING MATRIX FOR BASELINE TEST SERIES.
Parameter
Organics
Particulate
Metals
Isocyanates
Flow rate
Paint usage
Paint % volatile,
density
Sampling Location
Exhaust duct
Exhaust face, vicinity of painter
Exhaust duct
Exhaust face, vicinity of painter
Exhaust duct
Exhaust face, vicinity of painter
Exhaust duct
Exhaust face, vicinity of painter
Exhaust duct
Exhaust face
Booth
Booth
Sampling Method
NIOSH Method 1300a
BAAQMD Method ST-7b
EPA Method 25A
NIOSH Method 1300
EPA Method 5C
NIOSH Method 500a
EPA Draft Multiple Metalsd
NIOSH Method 7300a
OSHA Method 42e
OSHA Method 42
EPA Method 2C
ACGIHf
Gravimetric Manual
Recording
Grab
Number of
Tests
8
8
8
2
6
2
2
2
2
2
8
8
8
1 sample
per paint
Reference 7.
bReference 8.
GReference 9.
dReference 10.
eReference 11.
Reference 12.
NIOSH Method 1300 specifies that pure carbon disulfide (CS2) be used in extracting
solvents from charcoal tubes. However, experience has shown that CS2 does not completely
desorb most of the solvents present in Air Force coatings, including alcohols, toluene, and
cellosolves. Therefore, an appropriate extraction solvent mixture developed specifically for this
application was substituted for this test series. The improved solvent mixture, consisting of
5 percent acetone in CS2, proved successful in desorbing the various types of solvents typically
found in military coatings (see Volume II, Appendix E). Following their extraction from the
charcoal tubes, the extracts were analyzed, as specified in the method, via gas
chromatography/flame ionization detection (GC/FID). The paint solvent compounds targeted
for analysis are listed in Table 2.
15
-------
TABLE 2. ORGANIC SPECIES TARGETED FOR NIOSH METHOD 1300 ANALYSIS.
bis(2-Methoxyethyl) ether Ethoxyethanol PGMEA8
Butyl acetate MEKb Toluene
Ethyl acetate Methoxyacetone 2-Ethoxyethyl acetate
Ethylbenzene MIBK0 Xylenes (total)
aPGMEA = Propylene glycol monomethyl ether acetate.
bMEK = Methyl ethyl ketone.
CMIBK = Methyl isobutyl ketone.
Continuous emission monitoring (CEM) was conducted in both the split-flow duct and
the recirculation duct. Two CEM methods were employed: BAAQMD Method ST-7 and EPA
Method 25A. Method ST-7 procedure specifies that the sample stream pass through a catalytic
combustion tube, in which the organic compounds present in the stream are oxidized to CO2-
The oxidized sample stream then passes into a nondispersive infrared (NDIR) detector, which
continuously monitors the CO2 concentration. The combustion tube is periodically bypassed
to monitor the background CO2 concentration. The total organic carbon (TOG) measurement
is determined as the difference between the CO2 concentrations measured in the sample and
bypass streams. The method is not reliable when background CO2 constitutes more than
85 percent, on a molar basis, of the total carbon in the sample. The method also specifies that
the minimum concentration of organic compounds be 10 ppm if the appropriate NDIR cell is
used and that the minimum sensitivity of the NDIR is 2 percent of full scale.
EPA Method 25A uses an FID to measure the concentration of unburned
hydrocarbons in the sample stream. The FID is calibrated with propane, which has a detector
response factor that differs from the response factors of the paint solvents. In addition, the
presence of oxygenated organics, such as alcohols or esters, causes the organic compound
concentration to be underpredicted by the FID. In general, these factors and operational
constraints cause Method 25A to be less quantitative than Method ST-7. However, in instances
where either the sample TOC concentration is significantly less than the background CO2
concentration or a low signal-to-noise ratio is observed during Method ST-7 testing, Method 25A
provides the more reliable data.
2. Paniculate Sampling
Ambient air paniculate sampling was conducted using NIOSH Method 500. This
method is approved by several regulatory agencies for use in determining ambient particulate
concentrations in the workplace. Furthermore, it has been applied in the past to determine
particulate concentrations in Air Force paint spray booths during painting operations.
The EPA Method 5 particulate sampling procedure was used in the ventilation ducts.
This method is approved for source testing applications by the EPA, and has been used
successfully in the past to quantify particulate emissions from military painting operations.
3. Metals Sampling
NIOSH Method 7300 and the EPA Draft Multiple Metals sampling procedure were
used in the metals sampling. NIOSH Method 7300 is a reliable metals-sampling method that has
16
-------
been used previously in similar paint spray booth sampling efforts (References 2 and 4). The
EPA Draft Multiple Metals sampling procedure is also commonly used in source test applications.
4. Isocyanate Sampling
Several methods are available to determine airborne isocyanate concentrations,
including spectrophotometric, impinger, filter, and paper tape. The dry filter method (OSHA 42)
was selected because the logistical and safety issues associated with impinger methods
rendered their use infeasible in this test series. In the expected concentration ranges, the dry
filter system is as reliable as other integrated sampling methods (Reference 13).
C. PAINT CONSUMPTION DURING BASELINE TEST SERIES
Three types of paints were used in Booth 2 during the baseline test series: a two-part
polyester resin and aliphatic resin topcoat, a two-part polyurethane and aliphatic isocyanate
topcoat, and a two-part epoxy and polyamide primer. Both of the topcoats are prepared in a
1-to-1 pigment-to-catalyst volume ratio. The primer is mixed at a 2-to-1-to-1 water-to-pigment-to-
catalyst volume ratio. Samples of each pigment and catalyst were collected and analyzed for
density and percent volatiles. The results are presented in Table 3.
Paint usage was monitored by a sampling crew member stationed in the booth. For each
sampling event, the type of paint used, the total weight of the paint used, and the size and
orientation of the object painted were recorded. Paint usage data are summarized in Table 4.
The data related to the type and quantity of paint used in this test series may be compared to
paint usage data from the postmodification test series.
TABLE 3. RESULTS OF PAINT DENSITY AND PERCENT VOLATILE ANALYSES.
Paint Type
Dl Water Blank
Epoxy Primer
MIL-P-85582A
Polyurethane Green Topcoat
MIL-C-85285B
Polyurethane Green Topcoat
MIL-C-85285B, (QA duplicate)
Polyurethane White Topcoat
MIL-C-83286B
Percent Volatile Analysis
Initial
Weight
(9)
6.0
62.2
9.8
12.7
10.0
Final
Weight
(g)
0.1
35.4
7.0
9.2
6.4
Percent
Volatile
98
43
29
28
36
Measured Density
Pigment
or Epoxy
(kg/L)
(NA)a
1.91
1.20
1.19
1.35
Catalyst or
Curing Solution
(kg/L)
(NA)
0.92
0.98
0.96
0.93
*(NA) = Not analyzed.
17
-------
TABLE 4. PAINT CONSUMPTION RATES DURING BASELINE TEST SERIES.
Date and Test
16 April 1991,
Metals Test 1
16 April 1991,
Paniculate Test 1
17 April 1991,
Metals Test 2
17 April 1991,
Particulate Test 2
18 April 1991,
Organics Test 1
18 April 1991,
Organics Test 2
19 April 1991,
Isocyanates Test 1
19 April 1991,
Isocyanates Test 2
Approximate
Test Time
(minutes)
50
50
113
85
57
59
55
43
Time
1045-1057
1114-1125
1550
1448-1500
1505-1525
1530-1542
1550
1007-1031
1038
1129-1156
1200
1605-1608
1608
1635-1700
1703-1723
1730
1101-1124
,1127-1140
1144-1152
1155-1158
1717-1740
1745-1752
1754-1803
1807-1820
1824-1826
1126-1140
1143-1144
1147-1202
1209-1217
1220-1221
1518-1527
1530-1532
1537-1547
1550-1556
1558-1601
Paint/Solvent Type
Epoxy primer
Alcohol
Polyurethane topcoat
MEK
Epoxy primer
MEK
Polyurethane topcoat
MEK
Epoxy primer
Alcohol
Polyurethane topcoat
MEK
Polyurethane topcoat
MEK
Polyurethane topcoat
MEK
Polyurethane topcoat
MEK
Polyurethane topcoat
MEK
Polyurethane topcoat
MEK
Polyurethane topcoat
MEK
Quantity
(kg)
1.115
NAa
2.686
NA
0.585
0.130
0.844
0.169
0.399
NA-
1.683
0.308
2.217
0.314
2.025
0.292
0.337
NA
1.711
0.237
0.386
0.167
1.242
0.350
Painted Object
Cart
Not recorded
Stand
(12ftLx8ftW
x 3 ft H)b
Rails and misc.
parts on a table
(4 ft Lx 3.5ft
W x 3 ft H)
Rails and misc.
parts on a table
(4 ft L x 3.5 ft
W x 3 ft H)
and a cart (4 ft
Lx6ftW)
Parts on a table
(4 ft L x 3.5 ft"
W x 3 ft H)
and a cart (4 ft
Lx6ft W)
2 drums on a
3-ft-H table
and a hood
(3 ft L x 4 ft W
x 2.5 ft H)
2 drums on a
3-ft-H table
and a hood
(3 ft L x 4 ft W
x 2.5 ft H)
Comments
Alcohol sprayed
randomly during
cleaning
MEK sprayed
randomly during
cleaning
Object not
centered in room
Table placed 3 ft
from exhaust grid
aNA = Not applicable.
bL = long, W = wide, H = high.
18
-------
D. AIR FLOW RATE MEASUREMENTS
Flow rate measurements were made at the exhaust face and in the exhaust duct. The
face velocity at the exhaust face ranged from 110 to 150 fpm, corresponding to a volumetric flow
rate of 27,700 to 37,800 cfm. Table 5 lists the exhaust duct flow rate measurement results.
E.
RESULTS OF EXHAUST FACE MEASUREMENTS
The results of the exhaust face measurements are described below for the baseline test
series. The raw data for the baseline test series are presented in Volume II, Appendix F. For
purposes of discussing the appropriate split-position, the reduced data are presented in graphical
form in this section.
face:
Three assumptions were made in calculating the pollutant concentrations at the exhaust
• Each compound neither detected nor listed in the Material Safety Data Sheet (MSDS)
of the topcoat or primer was assumed to not be present.
• Each compound not detected but listed in the MSDS of the topcoat or primer
was assumed present at one-half the method detection limit.
• Because there are four sampling points at each exhaust face height,
pollutant concentrations shown in the figures in this section are average
concentrations for each height.
1. Organic Compounds
NIOSH Method 1300 was used to define average organic concentrations of individual
species during the sampling period. Because the method is an integrated sampling procedure,
TABLE 5. FLOW RATES MEASURED IN THE EXHAUST DUCT
DURING THE BASELINE TEST SERIES.
Date and Test
16 April 1991, Metals Test 1
16 April 1991, Paniculate Test 1
17 April 1991, Metals Test 2
17 April 1991, Paniculate Test 2
18 April 1991, Organics Test 1
18 April 1991, Organics Test 2
19 April 1991, Isocyanates Test 1
19 April 1991, Isocyanates Test 2
Volumetric Flow Rate
(scfm)
32,614
30,194
30,549
30,064
31,709
30,008
31,464
32,165
19
-------
the results of these tests were not used to draw conclusions regarding instantaneous or peak
concentrations, but, rather, the long-term average concentration.
Figure 8 presents the results of organic measurements at the exhaust face of Booth 2
during organics Tests 1 and 2. The concentrations reported in Figure 8 represent the sum of
all the organic species measured in the NIOSH Method 1300 speciation analyses. The highest
total organics concentration measured by integrated sampling was 34 mg/m3.
Figure 8 also shows the spatial distribution of organics at the exhaust face; the
organic species tend to concentrate in the lower section of the booth. For this reason, the air
stream with lower organic concentrations in the top section of the booth may be recirculated
without exceeding exposure standards.
2. Paniculate
Figure 9 presents the concentrations of particulate measured at the exhaust face of
the booth during particulate Tests 1 and 2. The two concentration profiles differ because the
paint quantities and object heights were different in each test. The results confirm the finding
of previous paint spray booth test programs that the particulate concentration at the exhaust face
decreases with increasing height. It is clear that particulate concentrations are very low in the
top section of the booth (less than 8 mg/m3 above 8 feet from the bottom of the booth).
The booth was equipped with two sets of particulate filters, one at the exhaust face
(downstream of the exhaust face sampling locations) and one at the booth intake. Because the
exhaust face measurements were obtained upstream from the exhaust face particulate filters, the
results do not affect the practical use of recirculating ventilation, even for the painting of large
objects.
3. Metals
The metals samples were analyzed for the presence of four metal species: strontium,
chromium, lead, and zinc. Strontium chromate (SrCrO^ is listed in the primer MSDS. Lead and
zinc are not listed as constituents in the MSOSs and were not detected in any of the samples.
Figure 10 presents the results of strontium chromate (SrCrO^ measurements at the
exhaust face during metals Tests 1 and 2. Strontium chromate concentrations were based on
strontium (Sr) or chromium (Cr) measurements. Because the strontium and chromium originated
from the strontium chromate in the primer, their measured concentrations were converted into
the equivalent strontium chromate concentration. Each data point in Figure 10 represents the
more conservative of the strontium and chromium results.
Because the metals samples were collected upstream of the exhaust face particulate
filter, they are not representative of recirculated concentration measurements.
4. Isocyanates
Figure 11 shows hexamethylene diisocyanate (HDI) concentrations measured at the
exhaust face during isocyanate Tests 1 and 2. Methylene diphenyl diisocyanate (MDI) and
toluene-2,4-diisocyanate (TDI) were not detected at the exhaust face and are not specified in the
MSDSs for the paints used.
20
-------
c
O
o
40-1
30-
20-
10 -I
—D— Test 1
"O~ Test 2
5 10
Height from floor, ft
15
Figure 8. Results of Organic Measurements at the Exhaust Face During Baseline Testing.
40 n
•D— Test 1
O" Test 2
5 10
Height from floor, ft
15
Figure 9. Measured Concentrations of Paniculate at the Exhaust Face
During Baseline Testing.
21
-------
2000 n
•Q— Test 1
O" Test 2
5 10
Height from floor, ft
15
Figure 10. Concentrations of Strontium Chromate Measured at the Exhaust Face.
o
I
c
o
o
8-
6 -
4 -
2-
—Q— Test 1
—O" Test 2
o o
5 10
Height from floor, ft
15
Figure 11. Baseline HDI Concentrations Measured at the Exhaust Face.
22
-------
The highest HDI concentration measured at the exhaust face was 0.0085 mg/m3.
As observed for the other pollutant species, HDI concentrations decrease with increasing height.
Because the samples were obtained upstream of the exhaust face paniculate filter, the
concentrations do not represent concentrations that would be returned to the booth intake in
recirculating ventilation modes.
F.
RESULTS OF EXHAUST DUCT MEASUREMENTS
The pollutant concentrations in the exhaust duct are critical parameters required to
determine the pollutant concentrations in a modified paint spray booth such as Booth 2.
Integrated sampling was conducted in the exhaust duct for volatile organic species, isocyanates,
particulate matter, and metals. OEM for VOCs was also conducted to measure instantaneous
organic concentrations during painting operations.
1. Organic Compounds
a. Integrated Sampling
Table 6 lists organic concentrations measured in the exhaust duct with NIOSH
Method 1300. This method was employed during all eight sampling events. As this method is
integrated, the results of these tests were not used to draw conclusions on instantaneous or
peak concentrations, but rather on the long-term average concentrations.
Table 6 lists only methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK),
n-butyl acetate, and 2-butanol. The other organic species listed in Table 2 were not detected.
The measured concentrations are far below the exposure limits. Hence, organic species are at
safe levels upon exiting the exhaust duct.
TABLE 6. CONCENTRATIONS OF ORGANIC COMPOUNDS MEASURED IN THE
EXHAUST DUCT.
Test Number
Organics Test 1
Organics Test 2
Particulate Test 1
Particulate Test 2
Metals Test 1
Metals Test 2
Isocyanates Test 1
Isocyanates Test 2
Concentration (mg/m3)
MEK
1.4
2.8
0.85
<0.15a
1.5
3.6
4.4
5.8
MIBK
4.2
2.9
3.6
0.74
<0.26
1.5
1.9
2.1
o-Butyl acetate
• 1.1
0.63
0.92
<0.15
<0.26
0.33
0.51
0.57
Toluene
0.64
0.34
0.50
0.15
0.55
0.43
0.25
0.26
= Compound not detected. Values listed are one-half the MDL
23
-------
b. Continuous Emission Monitoring Results
GEM was conducted during all eight sampling events. Two CEM methods were
employed, BAAQMD Method ST-7 and EPA Method 25A. During the baseline test series, the
maximum measured total VOC concentration was 702 ppm as CO2. Because a concentration
gradient exists at the exhaust face of the booth, only a fraction of the organics measured in the
exhaust duct will reenter the booth following modification of the ventilation mode to split-
flow/recirculating ventilation.
2. Paniculate
Table 7 lists the concentrations of particulate matter measured in the exhaust duct
during the baseline test series. Because Booth 2 has particulate filters at the intake faces, the
particulate measured in the exhaust duct does not represent particulate matter that would reenter
the booth upon recirculation.
3. Metals
Concentrations of metal compounds (strontium, chromium, lead, and zinc) measured
in the exhaust duct are listed in Table 8. The strontium and chromium both originate from the
strontium chromate in the primer.
These strontium and chromium concentrations are bulk duct concentrations. In the
split-flow/recirculating ventilation mode, the concentration in the recirculated stream is less than
the bulk exhaust duct concentration, due to the concentration gradient phenomenon at the
exhaust face. In addition, the booth is equipped with particulate filters at the booth intake.
These two factors help ensure that the concentration reentering the booth in recirculating
ventilation mode will be considered safe.
Because lead and zinc compounds were not detected in the exhaust duct and are
not listed in the MSDSs as paint constituents, the concentrations listed in Table 8 are based on
one-half the respective detection limits.
TABLE 7. CONCENTRATIONS OF PARTICULATE MATTER
MEASURED IN THE EXHAUST DUCT.
Test
Organics Test 1
Organics Test 2
Particulate Test 1
Particulate Test 2
Isocyanates Test 1
Isocyanates Test 2
Particulate Concentration
(mg/m3)
2.9
2.2
2.7
1.7
2.5
1.1
24
-------
TABLE 8. CONCENTRATIONS OF METAL COMPOUNDS MEASURED
IN THE EXHAUST DUCT.
Test
Metals Test 1
Metals Test 2
Concentration (mg/m3)
Lead
<0.0087a
< 0.0067
Zinc
<0.0087
< 0.0067
Strontium
0.059
6.035
Chromium
0.042
0.021
'< = Compound not detected. Values listed are one-half the MDL.
4. Isocyanates
HDI, MDI, and TDI were measured in the exhaust duct during the application of
isocyanate-containing topcoat. Isocyanate compounds were not detected in the exhaust duct,
and concentrations were conservatively assumed to equal one-half the method detection limits.
These values are listed in Table 9 for the two isocyanate tests.
G.
RESULTS OF MEASUREMENTS AT THE PAINTER
Concentrations of pollutant species measured outside and inside the painter's respirator
hood are listed in Table 10. Spreadsheets containing the reduced data are presented in
Volume II, Appendix F. Each compound not detected is assumed to be present at one-half the
MDL
The measured concentrations and calculated 8-hour time-weighted averages of organic
and isocyanate species: near the painter were all below the PEL values. No paniculate was
detected inside the painter's respirator.
The chromium results indicate that the measured concentrations were on the order of the
PEL and ACGIH TLV in effect during 1991 (0.05 mg/m3). However, because PELs and TLVs are
based on average exposure over an 8-hour workday, the measured concentrations do not
exceed OSHA or ACGIH standards. For instance, during metals Test 1, the chromium
concentration measured under the painter's hood exceeded the PEL value, presumably due to
leakage of booth air through the gap between the painter's hood and suit. Because the test
lasted about 1 hour, and because chromium-containing paints were not used in the subsequent
tests that day, this amounted to an average overall strontium chromate exposure (as chromium)
of 0.0079 mg/m3 (0.063 mg/m3 for 1 hour, and 0 mg/m3 for the remaining 7 hours of the
workday), less than the permissible 8-hour exposure limit in effect during 1991-92.
H.
RECIRCULATION AND SPLIT-FLOW CALCULATIONS
Results from sampling in the exhaust duct and at the exhaust face were used to predict
the concentrations of air pollutants that would result during split-flow/recirculating ventilation.
The calculations overestimate particulate-carried pollutants, such as metals and isocyanates,
because the removal of paniculate matter by intake filters is neglected. This section describes
the distribution of pollutants at the exhaust face, and the procedure for selecting the split height
and percent recirculation for subsequent split-flow/recirculating ventilation tests.
25
-------
TABLE 9. CONCENTRATIONS OF ISOCYANATE COMPOUNDS
MEASURED IN THE EXHAUST DUCT.
Test
Isocyanates Test 1
Isocyanates Test 2
Concentration (mg/m3)
HDI
< 0.00298
< 0.0038
MDI
< 0.0039
< 0.0038
TDI
< 0.0029
< 0.0038
= Compound not detected. Values listed are one-half the MDL
TABLE 10. CONCENTRATIONS OF AIR POLLUTANTS OUTSIDE AND INSIDE
THE PAINTER'S RESPIRATOR HOOD.
Test
Organics Test 1
Organics Test 2
Paniculate Test 1
Paniculate Test 2
Metals Test 1
Metals Test 2
Isocyanates Test 1
Isocyanates Test 2
Compound
MEK
MIBK
Toluene
n-Butyl acetate
Xylenes
MEK
MIBK
Toluene
n-Butyl acetate
Xylenes
Particulate
Paniculate
Chromium
Chromium
HDI
HDI
Concentration (mg/m3)
Outside
Respirator Hood
17
29
4.0
7.7
0.26
51
12
1.3
2.6
0.09
N.A.C
0.0037
0.176
0.168
< 0.0025
<0.0033
Inside
Respirator Hood
<0.12a
<0.12
< 0.050
<0.12
< 0.050
0.29
<0.10
< 0.039
<0.10
< 0.035
0.0
0.0
0.063
0.0074
<0.0025
< 0.0034
a< = Compound not detected. Values listed are one-half the MDL.
bNA = Not applicable.
CN.A. = Not available due to equipment failure.
26
-------
1. Vertical Distribution
The samples were collected at six different heights across the 14-foot-high exhaust
face: 1.5, 4.5, 6.5, 7.5, 10.6, and 13 feet. The fraction of pollutants found at or below each
height defines the fraction of hazardous constituents exhausted to a VOC control system with
the implementation of split-flow ventilation. This exhausted fraction is the definition of a in the
mass balance calculations in Section II.
Figure 12 shows the fractions of total organics, metals, particulate, and isocyanates
that were measured at or below each of the specified booth heights. Because two tests were
conducted for each pollutant category, and four samples per test were collected at each height,
each plotted point in Figure 12 represents the average of eight data points.
Approximately half of the pollutants were found at or below a height of 1.5 feet. Of
the toxic constituents, 96 percent were at or below 7.5 feet, and 98 percent were at or below
10.6 feet. Thus, if split-flow ventilation (without recirculation) was implemented in Booth 2, with
a split height of 7.5 feet, about 96 percent of the pollutants would exhaust through the lower duct
to a VOC control device.
2. Position of "Split"
The vertical distribution data and the maximum concentrations measured in the
exhaust duct were used to calculate an appropriate split height and percent recirculation for the
split-flow/recirculating ventilation test series. The maximum split height and percent recirculation
were restricted by industrial hygiene standards. The 8-hour average equivalent exposure was
compared to the Air Force exposure limit to ensure that the exposure during split-
flow/recirculating ventilation would not exceed industrial hygiene standards.
The following equation, derived in Section II, was used to calculate the concentrations
of toxic constituents in the recirculated air stream in split-flow/recirculating ventilation mode:
4H <14>
Ra )
where:
Ct = Concentration in top section of exhaust plenum
cunmod ~ Concentration in unmodified booth
a = The fraction of pollutants found below the split height
R = The recirculation ratio
Because the recirculating air stream mixes with the fresh air stream prior to entering
the booth, the concentration reentering the booth in the split-flow/recirculating ventilation mode
(C/V)) becomes
27
-------
1.0
OJ
«5
1
•o
I
i
o
u.
0.8
0.6
0.4
0.2-
0.0
TOTAL ORGANICS
METALS
ISCXJYANATES
PARTICULATES
10
Height from floor, ft
15
Figure 12. Vertical Distribution of Paint Constituents at the Exhaust Face.
28
-------
where:
Cin = The concentration at the intake face in the split-flow/recirculating ventilation
mode
Substituting for Ct gives c = C^^ (1 - fl) ^
* a
Cin was calculated for each toxic constituent and then compared to the PEL value.
The value of a was determined for each split height, based on the data in Figure 12. The value
of Cunmod, the concentration in the unmodified booth, was based on the maximum
concentrations observed in the exhaust duct during the baseline tests. These values are
.tabulated in Table 11.
The equivalent exposure of the pollutants reentering the booth was calculated using
equation (1) in Section II and using the OSHA PELs and ACGIH TLVs for that period of time,
1991-92. The objective was to ensure that the incremental addition to the exposure was much
less than allowable limits. According to 29 CFR 1910.1000, an Em value greater than unity (1.0)
implies that the toxicity level exceeds the exposure limit during an 8-hour work shift of a 40-hour
work-week. An Em less than unity implies that the equivalent exposure for the air mixture is
within acceptable limits. However, the HQ AFLC/SGBE imposed a safety factor of 4, reducing
the acceptable Em value to 0.25.
The incremental equivalent exposures were calculated for two different cases. The
first case assumed that the painter was exposed to the concentrations in the booth for the entire
8-hour workday. The second assumed that the painter was subjected to the booth conditions
for only 2 hours of each workday, and was exposed to background concentrations, assumed
to be zero, for the remaining 6 hours of each workday.
Figure 13 shows the incremental change in Em corresponding to the various split
heights. As the split height decreases, the intake Em increases. The results indicate that with
a split height at or below 6.6 feet, the intake Em for metals exceeds the HQ AFLC/SGBE criterion
of 0.25 (if personnel are exposed in a booth throughout an 8-hour workday). The final split
height selected was 7.5 feet, for an estimated 8-hour exposure intake Em for metals of 0.09 and
a 2-hour exposure intake Em for metals of 0.022. This corresponds to about 40-percent
recirculation, because the height of the exhaust face through which air actually flows is 12 feet,
whereas the height of the booth is 14 feet. This split height and percent recirculation were
considered sufficient to determine the consequences of recirculation while ensuring that the
concentrations of pollutants reentering the booth were well below applicable safety limits.
Tables 12 and 13 present the intake Em results for the split height of 7.5 feet.
Table 12 was prepared assuming that the painter is exposed to the concentrations in the booth
throughout the workday. Table 13 was prepared assuming that the painter is exposed to booth
concentrations for only 2 hours of each workday. In both cases, the Em values at the intake are
far below the HQ AFLC/SGBE criterion of 0.25. In each case, the primary factor is the
hexavalent chromium originating from strontium chromate. All of the intake concentration
calculations, including those for chromium, were based on the baseline concentrations in the
exhaust duct. Because the strontium chromate is paniculate matter that should be collected at
the intake face paniculate filters, these calculations are considered very conservative.
29
-------
TABLE 11. MAXIMUM CONCENTRATIONS OF POLLUTANTS MEASURED IN THE
EXHAUST DUCT DURING THE BASELINE TEST SERIES.
Compound
Zinc
Lead
Chromium
MDI
TDI
HDI
MEK
MIBK
n-Butyl acetate
Toluene
Xylenes
Ethyl acetate
2-Butanol
Methoxyacetone
Ethoxyethanol
Ethylbenzene
PGMEA
2-Ethoxyethyl acetate
2-Methoxyethyl ether
Test
Metals Test 1
Metals Test 1
Metals Test 1
Isocyanates Test 1
Isocyanates Test 1
Isocyanates Test 1
Isocyanates Test 1
Organics Test 1
Organics Test 1
Organics Test 1
Metals Test 1
Metals Test 1
Metals Test 1
Metals Test 1
Metals Test 1
Metals Test 1
Metals Test 1
Metals Test 1
Metals Test 1
Type of
Paint Used
Primer
Primer
Primer
Topcoat
Topcoat
Topcoat
Topcoat
Topcoat
Topcoat
Topcoat
Primer
Primer
Primer
Primer
Primer
Primer
Primer
Primer
Primer
Highest Exhaust
Duct Concentration
(mg/m3)
<0.0083a'b
<0.0083a'b
0.042
<0.0038a'b
<0.0038a'b
<0.0038a
5.8
4.2
1.1
0.64
<0.11a
<0.26a
<0.28a
<0.73a'b
<0.95a'b
<0.11a
<0.26a'b
<0.55a
-------
(a) 8-Hour Exposure
A— organics
metals
socyanates
46 8
Split Height, ft
10 12
1.2 T
0.8 --
0.6 --
0.4 --
(b) 2-Hour Exposure
-x-
organics
metals
isocyanates
Split Height, ft
Figure 13. Intake Em Versus Split Height.
31
-------
TABLE 12. £m AT THE INTAKE OF A SPUT-FLOW/RECIRCULATING VENTILATION
PAINT SPRAY BOOTH, ASSUMING 40-PERCENT RECIRCULATION AND
8 HOURS OF EXPOSURE PER DAY.
Compound
Hexavalent chromium
HDI
MEK
MIBK
n-Butyl acetate
Toluene
Xylenes
Ethyl acetate
2-Butanol
1991-92
ACGIH TLV
(mg/m3)
0.05
0.034
590
205
713
377
434
1,440
305
1991-92
OSHA PEL
(mg/m3)
0.05
0.04
590
205
710
375
435
1,400
305
Booth Intake Concentration
During Split-flow/
Recirculating Ventilation
C-
(mg/m3)
0.0043
0.00
0.56
0.406
0.106
0.062
<0.011b
< 0.025
< 0.027
Equivalent exposure (£„,) for the organics
Cin/(PEL
or TLV)8
0.09
0.00
0.00095
0.0020
0.00015
0.00017
2.5 x 10*5
1.8X10'5
8.9 x 10~5
0.0034
a£m calculations based on the PEL or TLV, whichever is the smaller number for each
compound.
b< = Compound not detected. Values listed are one-half the MDL.
32
-------
TABLE 13. Em AT THE INTAKE OF A SPUT-FLOW/RECIRCULATING VENTILATION
PAINT SPRAY BOOTH, ASSUMING 40-PERCENT RECIRCULATION AND
2 HOURS OF EXPOSURE PER DAY.
Compound
Hexavalent chromium
HDI
MEK
MIBK
n-Butyl acetate
Toluene
Xylenes
Ethyl acetate
2-Butanol
1991-92
ACGIH TLV
(mg/m3)
0.05
0.034
590
205
713
377
434
1,440
305
1991-92
OSHA PEL
(mg/m3)
0.05
0.04
590
205
710
375
435
1,400
305
Booth Intake Concentration
During Split-flow/
Recirculating Ventilation
°i"3
(mg/m3)
0.0011
0.00
0.140
0.101
0.0265
0.0155
<0.0028b
< 0.0062
< 0.0068
Equivalent exposure (£„,) for the organics
Cjn/(PEL or
TLV)a
0.022
0.00
2.4 x10"4
5.0 x10"4
3.7 x 10~5
4.1 x 10'5
6.3 x 10'6
4.5 x 10'6
2.2 x 10'5
0.0008
aEm calculations based on the PEL or TLV, whichever is the smaller number for each
compound.
b< = Compound not detected. Values listed are one-half the MDL
33
-------
SECTION V
POSTMODIFICATION TEST MATRIX AND RESULTS
A 3-week test series was conducted during June and July 1992 to characterize
postmodification booth operations, again using Booth 2 as the test site. The postmodification
test matrix is summarized in Tables 14 and 15. In the combined split-flow/recirculating
ventilation mode, six sampling events occurred for organics, and five for each of the following
parameters: paniculate, isocyanates, and metals. In the split-flow ventilation mode, three
sampling events were conducted: two for particulate and one for organics.
Throughout this section, the exhaust conduit from the lower plenum is referred to as the
split-flow duct and the exhaust conduit from the upper plenum as the recirculation duct.
A. SAMPLING LOCATIONS
Figure 14 shows the test locations. These include the two intake faces (site A), over and
under the painter's airline respirator hood (Site B), the exhaust face (Site C), and in the split-flow
and recirculation ducts (Sites D and E). Site El was used during the split-flow/recirculating
ventilation tests; Site E2 was used during the split-flow, single-pass tests.
The concentration of organics entering the booth was monitored at Site F. The monitor
continuously recorded duct concentration, and also activated an automatic control system that
converted the booth into single-pass operation whenever the measured concentration exceeded
a preset concentration.
Because the recirculated stream is mixed with fresh intake air, the VOC concentration
measured at the feedback FID is lower than the bulk concentration exiting the booth through the
recirculation duct. During the initial split-flow/recirculating ventilation tests, the feedback FID was
positioned just downstream of the fresh air mixing point. Because the data indicated that the
flow was not well mixed at that location, the feedback FID sampling location was moved to just
upstream from one of the booth intake faces. This location yielded a more representative bulk
VOC concentration.
Three sampling locations were used at each of the two intake faces. The intake
sampling locations are illustrated in Figure 15. The sampling locations at the exhaust face were
identical to the locations used in the baseline test series, illustrated in Figure 7 (see Section IV).
B. SAMPLING METHODS
For the postmodification test series, the sampling and analytical methods used were the
same as those employed during the baseline test series (see Section IV), with one exception:
the isocyanate tests in the vicinity of the painter and in the two ducts were conducted using
NIOSH Method 5521, an impinger method. This type of method was selected so that, in the
event monomeric isocyanates were present in the flow, they would be collected in the impinger
solution.
Because the results of this test series are used to determine whether the combined split-
flow/recirculating ventilation strategy is safe and practical, it was important that the organic,
particulate, metal, and isocyanate concentrations in the ventilation ducts be accurately
34
-------
TABLE 14. SAMPUNG MATRIX FOR SPUT-FLOW/RECIRCULATING VENTILATION
TESTS.
Parameter
Organics
Particulate
Metals
Isocyanates
Flow rate
Paint usage
Paint % volatile,
density
Sampling Location
Split-flow and recirculation ducts
Exhaust and intake faces, painter
vicinity
Split-flow and recirculation ducts
Exhaust and intake faces, painter
vicinity
Split-flow and recirculation ducts
Exhaust and intake faces, painter
vicinity
Split-flow and recirculation ducts
Exhaust and intake faces
Painter vicinity
Split-flow duct
Exhaust and intake faces
Booth
Booth
Sampling Method
NIOSH Method 1300a
BAAQMD Method ST-7b
EPA Method 25AC
NIOSH Method 1300
EPA Method 5C
NIOSH Method 500a
EPA Draft Multiple
Metalsd
NIOSH Method 7300a
NIOSH Method 5521 a
OSHA Method 42e
OSHA Method 42
NIOSH Method 5521
EPA Method 2C
ACG|Hf
Gravimetric
Grab
Number
of Tests
21
21
21
6
16
5
5
5
5
1
5
5
21
18
21
1 sample
per paint
type used
Reference 7.
bP»eference 8.
cReference 9.
dReference 10.
Reference 11.
Reference 12.
35
-------
TABLE 15. SAMPLING MATRIX FOR SPLIT-FLOW TESTS.
Parameter
Organics
Particulate
Flow rate
Paint usage
Paint % volatile,
density
Sample Location
Split-flow and recirculation ducts
Exhaust and intake faces, painter
vicinity
Split-flow and recirculation ducts
Exhaust and intake faces, painter
vicinity
Split-flow duct
Exhaust and intake faces
Booth
Booth
Sampling Method
NIOSH Method 1300a
BAAQMD Method ST-7b
EPA Method 25AC
NIOSH Method 1300
EPA Method 5C
NIOSH Method 500a
EPA Method 2C
ACGIHd
Manual recording
Grab
Number of
Tests
3
3
3
1
3
2
3
3
3
1 sample
per paint
type used
Reference 7.
bReference 8.
cReference 9.
Reference 12.
36
-------
FRESH MAKEUP
AIR INTAKE
BOOTH INTAKE
DUCT
SPLIT-FLOW
DUCT
Figure 14. Sampling Locations for the Postmodification Test Series.
•
•
•
1
2
3
60 in.
(5ft.) *
t '
I 19
I ^
-j- 1.5 in.
142
(11.8
*
I
•in.
3ft.)
Figure 15. Sampling Locations at One of Two Intake Faces.
37
-------
determined. An additional objective was to compare concentration profiles of these compounds
at the exhaust face of the booth with the concentration profiles obtained in the baseline test
series. The sampling methods were selected to safely achieve these objectives and obtain
accurate results. The selection process used to identify appropriate sampling procedures is
presented in Section IV.B.
C. RESULTS OF PAINT CONSUMPTION DURING THE POSTMODIFICATION TEST
SERIES
Three types of paint were used in Booth 2 during the postmodification test series: water-
borne epoxy primer, polyurethane topcoats, and water-borne acrylic topcoats. The epoxy primer
and polyurethane topcoats are two-part coatings. The epoxy primer is mixed at a 3-to-1
epoxy-to-curing-solution volume ratio, and the polyurethane topcoats are prepared in a 3-to-1
pigment-to-catalyst volume ratio (green and gunship gray) or a 1 -to-1 pigment-to-catalyst volume
ratio (other pigments). The acrylic topcoats required mixing the pigment with water in a 3-to-1
ratio. Paint samples were collected and analyzed for density and percent volatiles. The results
are presented in Table 16.
° Paint usage was monitored by a field crew member, stationed in the booth, who recorded
the type of paint used, the total weight of paint used during the test event, and the type and size
of the object painted. The paint usage data are summarized in Table 17.
0. AIR FLOW RATE MEASUREMENTS
Prior to testing, the fans were balanced to achieve flow characteristics similar to those
observed during the baseline testing. The face velocity through the booth was 100 fpm,
corresponding to a volumetric flow rate of about 25,200 cfm. Table 18 lists the flow rate results
for the booth intake, the split-flow duct (lower plenum), and the recirculation duct (upper
plenum).
The booth intake velocity was measured after each test using an anemometer. The face
was divided into sections and the velocity was measured in the center of each section. The
volumetric flow rate was calculated using the following equation:
Q = £ M/) <17>
in which:
Q = Volumetric flow rate at the booth face
vf = Velocity measured at the center of section / using an anemometer
Ai = Area of section /
The intake face flow rate values were corrected from cfm to dscfm based on the correction factor
calculated for the split-flow duct.
The volumetric air flow rate in the split-flow duct was measured during every sampling
event. The flow rate in the recirculation duct was determined by subtracting the split-flow duct
flow rate from the total booth intake flow rate. The site for the recirculation duct sampling did
not meet the EPA Method 1 criterion (greater than two stack diameters downstream from a duct
38
-------
TABLE 16. RESULTS OF PAINT DENSITY AND PERCENT VOLATILE ANALYSES.
Paint Type
Dl Water Blank
Lt. Green Primer
MIL-P-85582A
Drk. Green Top Coat
MIL-C-85285B,
34092,G/S,Type I
Gray Top Coat
MIL-C-85285B,
16473, Type I
Acrylic Gloss Red
Top Coat
Acrylic Gloss (Water
Reducible) Blue Top
Coat
Gunship Gray Top
Coat
MIL-C-85285B,
36118,G/S,Typel
Gray Top Coat
MIL-C-85285B,
36173, Type I
White Top Coat
MIL-C-85285B,
17925, Type I
White Top Coat
MIL-C-85285B,
17925, Type I
(QA Duplicate)
Percent Volatile Analysis
Initial
Weight
(9)
7.0
18.1
9.0
10.1
21.9
20.9
15.8
12.2
10.8
12.1
Final
Weight
(9)
0
7.4
5.6
6.6
6.2
7.3
10.1
8.5
7.5
8.2
Percent
Volatile
100
59.1
37.8
34.7
71.7
65.1
36.1
30.3
30.6
32.2
Density Measurement
Measured Density
Pigment
or Epoxy
(kg/L)
(NA)a
1.33
1.20
'
1.36
1.06
1.19
1.22
1.18
1.47
1.45
Catalyst
or
Curing
Solution
(kg/L)
(NA)
1.04
1.09
0.934
1.01
1.01
1.09
1.07
0.943
0.970
Published Density
Pigment
or
Epoxy
(kg/L)
1.0
1.29
1.194
1.396
1.055
1.181
1.403
1.233
1.473
1.473
Catalyst
or
Curing
Solution
(kg/L)
1.0
1.01
1.080
0.969
1.000
1.000
1.080
1.080
0.969
0.969
3(NA) = Not analyzed.
39
-------
TABLE 17. PAINT CONSUMPTION RATES DURING POSTMODIFICATION TEST SERIES.
Dale and Test
16 June 1992,
Organics Test 1
17 June 1992,
Organics Test 2
17 June 1992,
Organics Test 3
IB June 1992,
Organics Test 4
19 June 1992,
Paniculate Test 1
19 June 1992,
Paniculate Test 2
22 June 1992,
Paniculate Test 3
Approximate
Test Time
(minutes)
81
46
43
25
37
33
68
Time
1319-1322
1351-1402
1430-1431
1442-1505
1508-1509
1000-1007
1011-1018
1021-1022
1030-1036
1038-1043
1045-1046
1518-1523
1525-1531
1532-1533
1541-1548
1551-1555
1557-1601
09494)957
0959-1009
1012-1014
0825-O839
0841-0847
0849-0857
09000902
1400-1405
1408-1413
1416-1422
1424-1430
1432-1433
0959-1018
1020-1022
1031-1039
1042-1107
Paint/Solvent
Type
Green Primer
MEK
Gray 16473
MEK
Green Primer
MEK
Gray 16473
MEK
Green Primer
MEK
Dark Green
Green Primer
MEK
White
MEK
Green Primer
MEK
White
MEK
Safety Red
Quantity
0-9)
0.995
0.269
NAb
N.A."
0.519
0.447
0.183
0.485
0.499
0.193
0.475
0.536
0.266
0.574
0.372
0.617
0.457
0.420
0.342
0.486
0.263
0.167
0.300
0.570
0.543
0.471
0.515
0.228
0.423
0.339
0.636
0.683
Painted Object
Auxiliary Ramps
(7ftLx2«Wx1«H)'
two on 3-ft-H table
Auxiliary Ramps,
same as above, turned
over
Large wood & metal
box
(3.5 ft L x 3 ft W x 2
ftH)
on 2.5-ft-H table
Udders (2)
(6.5 ft L x 2 ft W)
against left wall 4 & 7 ft
from grid
Ladders (2)
5 & 7 feet from grid
against left wall
Bowser
(BftLxSftWxSftH)
mostly centered In room
Ladders (2) and Bowser
Comments
Lost power from
132210 1351
Added paint twice
for each color (start
and middle)
1042: painter
kneeling with back
to grid pointing
paint gun up under
object
Painter kneeled
and sprayed MEK
through paint gun
toward grid.
1545, 1553: painter
facing away from
grid
Painted folded,
unfolded, and
turned over
Ladders painted
partially folded, not
turned over
1412-1416. 1426:
painter facing away
from grid
1016: pump fell off
painter's belt
Paint gun cleaned
with water after
painting with red
paint completed
•L = long, W = wide. H = high.
bNA • Not available. Final paint gun weight not obtained.
CONTINUED
40
-------
TABLE 17. PAINT CONSUMPTION RATES DURING POSTMODIFICATION TEST SERIES
(CONTINUED).
Dale and T««l
22 June 1992,
Metals Test 1
23 June 1992.
Metals Test 1
(continued)
23 June 1992,
Isocyanates Test 1
23 June 1992,
Organics Test 5
24 June 1992,
Particulate Test 4
24 June 1992.
Metals Test 2
25 June 1992,
Metals Test 3
Approximate
T««t Tim*
(minute*)
41
33
55
54
63
63
52
•
Time
1412-1418
1420-1428
1432-1449
1452-1453
0735-0749
0758-0810
0808
•topped
traverse
0811-0812
1027-1050
1054-1109
1111-1119
1121-1122
1440-1454
1457-1507
1510-1523
1525-1529
1433-1434
0920-0926
09300946
095OO957
1011-1023
1023
1427-1444
1449-1508
1512-1526
1529-1530
08384854
0856-0927
0929-0930
Paint/Solvent
Typ.
Green Primer
MEK
Qreen Primer
MEK
White
MEK
White
MEK
Ugh! Blue
MEK
Green Primer
MEK
Green Primer
MEK
Quantity
P<9)
0.646
0.900
0.680
0.334
1.054
0.252
0.804
1.067
0.631
0.241
0.901
0.784
1.021
0.393
0.214
0.891
0.952
0.574
0.478
0.264
0.569
0.570
0.640
0.417
0.528
0.643
0.280
Painted Object
Comfort Pallet
(6 « L x 6 ft W x
7.5 ft H)*
on skids 1 ft off floor
(top, Inside latrines &
kitchen)
Comfort Pallet
(sides and flat plates)
Comfort Pallet
(kitchen and latrines)
Comfort Pallet
(kitchen & latrines)
Comfort Pallet
(sides and top)
Splitters (4)
(3ftLx2ftWx2ftH)
on 2.5-ft-H table
Brake parts (5)
(18-ln-dlameter x
I.Wn-W)
Wheel hubs (10)
(18-ln-dlameter x 1-ft-
H)Ramp
(7ftLx4ftWx
2.5 ft H)
on 2.5-ft-H tables
Comment*
Painter inside
pallet for 25
minutes of test
No grid samples
0751-0758: painter
Inside pallet;
sample outside of
painter respirator
was detached
Sample outside of
painter respirator
was reattached at
1050; inside pallet,
1100-1119
MEK sprayed;
painter pointed
paint gun left,
parallel to grid
0926: Sample
outside of painter
respirator was
reattached
Power loss: booth
switched to single-
pass twice,
0956-1006
MEK sprayed,
painter facing grid
0839-0840:
Masking
MEK sprayed,
painter kneeling
1.5 ft from grid,
parallel to grid
"L - long, W - wide, H - high.
CONTINUED
41
-------
TABLE 17. PAINT CONSUMPTION RATES DURING POSTMODIFICATION TEST SERIES
(CONTINUED).
Date and Test
25 June 1992,
Isocyanates Test 2
25 June 1992,
Isocyanates Test 3
26 June 1992,
Metals Test 4
26 June 1992,
Metals Test 5
29 June 1992,
Paniculate Test 5
30 June 1992,
Isocyanates Test 4
30 June 1992,
Isocyanates Test 5
30 June 1992,
Organlcs Test 6
Approximate
T«»t Tim*
(minutes)
61
50
73
71
64
58
53
60
Time
1126-1156
1159-1224
1226-1227
1452-1531
1534-1542
1544-1545
0838-0857
0901-0919
0923-0925
0933^)943
0946-0951
0954-O955
1132-1156
1159-1212
1215-1222
1233-1240
1242-1243
1344-1413
1416-1444
1447-1448
0804-0826
0829-0845
0848-0858
0901-0902
1106-1133
1136-1155
1158-1159
1439-1452
1501-1514
1517-1525
1528-1535
1538-1539
Paint/Solvent
Type
White
MEK
Gunshlp Gray
MEK
Green Primer
MEK
Gunship Gray
MEK
Green Primer
MEK
Gunshlp Gray
MEK
Green Primer
MEK
Gunshlp Gray
MEK
Quantity
(V9)
0.931
0.882
0.228
0.734
0.377
0.224
0.429
0.745
0.026
0.725
0.276
0.214
0.900
0.978
0.832
0.942
0.274
0.600
0.487
0.316
0.798
0.831
0.600
0.347
0.603
0.625
0.172
0.794
0.723
0.549
0.466
0.233
Painted Object
Brake parts (5)
Wheel hubs (10)
Ramp
on 2.5-ft-H tables
Splitters (4)
2 on ground,
2 on table
Thrust Reverser
(7-ft-dlameter x
3.5-ft-H)'
on 2.5-ft-H cart
(Inside and outside)
Thrust Reverser
OEC Panels (7)
(2 ft L x 2.5 ft W x 1 ft
H)" (concave)
on 2.5-ft-H tables
QEC Panels (7)
C-141 Engine
(6-ft-diameter x 25-ft-L)
on 2.5-ft-H cart
C-141 Engine
Comments
MEK sprayed;
painter kneeling;
paint gun angled
down toward grid
Painter sprayed
MEK while
standing; paint gun
angled down
toward grid
0924-0929: lost
power; booth
converted to
single-pass
Painter sprayed
MEK while
standing; paint gun
angled down
toward grid; then
painter kneeling,
parallel to grid
1222-1230: Painter
left booth to get
more paint
Painter sprayed
MEK down and left,
while standing.
Painter sprayed
MEK to left.
kneeling, parallel to
grid
Painter sprayed
MEK back and left;
paint gun angled
slightly down
Painter sprayed
MEK left; paint gun
angled down,
parallel to grid
1452-1501: Painter
waiting for more
paint
Painter sprayed
MEK while
standing; paint gun
angled toward grid
*L = long, W = wide, H = high.
CONTINUED
42
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TABLE 17. PAINT CONSUMPTION RATES DURING POSTMODIFICATION TEST SERIES
(CONCLUDED).
Date and Test
1 July 1992.
Split-flow
Organics Test 1
1 July 1992,
Split-flow
Paniculate Test 1
1 July 1992,
Split-flow
Paniculate Test 2
Approximate
Test Time
(minutes)
63
57
64
Time
0805-0820
0824-0837
0841-0905
0907-0908
1103-1122
NA°
1130-1144
1149-1200
NA
1446-1526
1529
1535-1550
Paint/Solvent
Type
Gray 36173
MEK
Green Primer
MEK
Gunship Gray
MEK
Gunship Gray
MEK
Gunship Gray
Quantity
(Kg)
0.751
0.606
0.950
0.152
0.473
1.597"
1.113
1.001
1.620d
1.125
NA°'d
0.962
Painted Object
C-141 Engine
QEC Panels (9)
Ramp (1)
Sheetmetal Pieces (3)
Wooden Box
(4 ft L x 3 ft W x 2 ft H)a
Stand
(7.5 ft H)
2 Sheetmetal
(3 ft L x 2 ft W)
Comments
0837: Lost power
Painter sprayed
MEK while
standing; paint gun
angled down,
parallel
Second painter —
faster strokes,
more overspray
MEK sprayed into
solvent waste can;
remainder poured
into can
Second painter —
faster strokes,
more overspray
MEK sprayed into
solvent waste can
°NA = Not applicable.
dMEK sprayed directly Into waste can; no observable MEK emissions.
43
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TABLE 18. VOLUMETRIC FLOW RATES AT INTAKE FACES, SPLIT-FLOW DUCT, AND
RECIRCULATION DUCT.
Date
Test Type
Flow Rate (dscfm)
Intake Face
Spin-flow
Duct
Recirculation
Ducf
Fraction
Recirculation
Split-flow/Recirculating Ventilation Tests
17 June 1992
18 June 1992
19 June 1992
22 June 1992
23 June 1992
24 June 1992
25 June 1992
26 June 1992
29 June 1992
30 June 1992
Organics Test 2
Organics Test 3
Organics Test 4
Paniculate Test 1
Paniculate Test 2
Paniculate Test 3
Metals Test 1
Isocyanates Test 1
Organics Test 5
Paniculate Test 4
Metals Test 2
Metals Test 3
Isocyanates Test 2
Isocyanates Test 3
Metals Test 4
Metals Test 5
Paniculate Test 5
Isocyanates Test 4
Isocyanates Test 5
Organics Test 6
Average (± Standard Deviation)
23,126
22,494
27,251
22,741
Not measured
26,058
25,589
27,625
24,629
25,740
25,224
Not measured
21,744
27,157
24,897
26,472
27,197
28,395
28,587
24,342
25,500 ±2,000
12,157
12,026
12,410
12,201
12,169
12,163
12,135
12,057
11,942
12,035
11,897
12,127
12,189
12,093
12,158
12,223
12,038
12,117
12,099
12,115
12,100 ±100
10,969
10,468
14,841
10,540
NAb
13,895
13,454
15,568
12,687
13,705
13,327
NA
9,555
15,064
12,739
14,249
15,159
16,278
16,488
12,227
13,400 ±1,200
0.47
0.47
0.54
0.46
NA
0.53
0.53
0.56
0.52
0.53
0.53
NA
0.44
0.55
0.51
0.54
0.56
0.57
0.58
0.50
0.53 ±0.09
Split-flow Ventilation
1 July 1992
Organics Test 1
Paniculate Test 1
Paniculate Test 2
Average (± Standard Deviation)
23,482
28,221
25,957
25,900 ±2,400
12,338
12,402
12,421
12,390 ±40
11,144
15,819
13,536
13,500 ±1,300
NAC
NAC
NAe
"Calculated by difference.
bNA = Not applicable.
CNA, not recirculating in split-flow mode.
44
-------
disturbance); therefore, the flow pattern in the recirculation duct was cyclonic. Consequently,
the flow rate was not measured in the recirculation duct.
E. RESULTS OF EXHAUST AND INTAKE FACE MEASUREMENTS
Results of the exhaust and intake face measurements are described below for both the
split-flow and the combined split-flow/recirculating ventilation tests. Spreadsheets containing the
reduced data are presented in Volume II, Appendix G. The data quality objectives and results
are presented in Volume II, Appendix H. The calculated concentrations incorporate the following
assumptions:
• Each compound not detected was assumed to be present at one-half the method
detection limit (MDL).
• The concentrations at the exhaust and intake faces were determined by averaging
concentrations measured at the sampling points located at each individual height.
For all paint constituents measured, the results are consistent with the concentration
gradient phenomenon upon which the split-flow concept is based. In addition, the results at the
booth intake reaffirm the safety of the recirculation concept, as average concentrations measured
at the booth intake were consistently and significantly less than the corresponding OSHA PELs.
1. Organic Compounds
NIOSH Method 1300 was used to define average organic concentrations of individual
species during the sampling period. Because NIOSH Method 1300 is an integrated sampling
procedure, the results of these tests were not used to draw conclusions regarding instantaneous
or peak concentrations, but, rather, the long-term average concentration. This type of data
treatment is consistent with both Air Force and OSHA PEL and TLV limits. They are average
concentrations over a specified length of time. Thus, conclusions can be drawn from these
results regarding the efficiency of the modification to remain within Air Force and OSHA limits.
Figures 16 through 21 present the results of organic measurements during the
combined split-flow/recirculating ventilation tests. Figure 22 presents results at the intake and
exhaust faces for the one split-flow test. The concentrations reported in these figures represent
the sum of all the organic species measured in the NIOSH Method 1300 speciation analyses.
The intake face results are indicated by dashed lines, and the exhaust face results by solid lines.
The concentration trends indicated by the plots confirm the finding of previous tests
that the solvent concentration at the exhaust face decreases with increasing distance from the
painter and painted objects. The variability in the concentration trends from one test to the next
is explained by the range of painting conditions, paint types, and object sizes and shapes
encountered during testing.
Two types of paint were used during the organics tests, epoxy primer and
polyurethane topcoat. Because primer volatiles include both water and VOCs, less total organics
are observed during primer painting than during polyurethane topcoat painting. During organics
Tests 1,2, and 3, both primer and topcoat were used. During organics Test 4, only primer was
used, and the measured organics concentrations were less than in other tests. During organics
Tests 5 and 6, only topcoat was used.
45
-------
30 -i
20 -
_o
CD
U
c
o
U
10-
—D— Exhaust face
—O" Intake face
5 10
Height from floor, ft
15
Figure 16. Results of Organic Measurements at the Intake and Exhaust Faces
During Split-flow/Recirculating Ventilation—Test 1.
50-
40-
E 30
o
20-
10-
—CD— Exhaust face
—O— Intake face
5 10
Height from floor, ft
15
Figure 17. Results of Organic Measurements at the Intake and Exhaust Faces
During Split-flow/Recirculating Ventilation—Test 2.
46
-------
o
U
50 -i
40-
30-
20-
10-
cx
—D— Exhaust face
—O— Intake face
,O
5 10
Height from floor, ft
15
Figure 18. Results of Organic Measurements at the Intake and Exhaust Faces
During Split-flow/Recirculating Ventilation—Test 3.
|
c
0)
u
c
O
O
20 -i
15-
10-
5-
—D— Exhaust face
—O" Intake face
o o
5 10
Height from floor, ft
15
Figure 19. Results of Organic Measurements at the Intake and Exhaust Faces
During Split-flow/Recirculating Ventilation—Test 4.
47
-------
30-i
<•> 20-
c
o
u
c
3 10
o
—D— Exhaust face
—O— Intake face
5 10
Height from floor, ft
15
Figure 20. Results of Organic Measurements at the Intake and Exhaust Faces
During Split-flow/Recirculating Ventilation—Test 5.
1
§
I
40-1
30-
20-
10H
o--
—[3— Exhaust face
--O— Intake face
--O
o
L— —
5 10
Height from floor, ft
15
Figure 21. Results of Organic Measurements at the Intake and Exhaust Faces
During Split-flow/Recirculating Ventilation—Test 6.
48
-------
12 -]
10-
8-
6-
4 -
2-
—Q— Exhaust face
—O— Intake face
o -o -o
5 10
Height from door, ft
15
Figure 22. Results of Organic Measurements at the Intake and Exhaust Faces
During Split-flow Ventilation—Test 1.
The heights and dimensions of objects painted included a 1-foot-high auxiliary ramp;
a 7.5-foot-high comfort pallet; and a 6-foot-diameter, 25-foot-long C-141 engine mounted on a
2.5-foot-high cart. The organics concentrations decrease more rapidly with height for small
objects, such as the ramps painted during organics Tests 1 and 2 (Figures 16 and 17), than for
large objects, such as the C-141 engine painted during organics Test 6 (Figure 21). For each
example, the data confirm the expectation of a top-to-bottom concentration gradient, and the
total organic concentration measured at the intake faces is significantly less than the calculated
STEL for a paint mixture of 350 ppm (Reference 6).
2. Particulate
Paniculate testing was conducted in the booth during the application of epoxy primer,
polyurethane topcoat, and water-based topcoat.
Figures 23 through 27 present the paniculate concentrations measured at the intake
and exhaust faces during combined split-flow/recirculating ventilation. Figures 28 and 29 present
the concentrations measured at the intake and exhaust faces during split-flow ventilation. With
the exception of one data point, participate matter was not detected at the booth intake face; all
other intake face data on the plots represent one-half the MDL The single intake value in
Figure 24 that is greater than the MDL is an average of two samples obtained at that height (one
at each intake face); one sample value was below the detection threshold and assumed to be
one-half the MDL, and the other was measured at 7.3 mg/m3, larger than the average
concentrations measured at the exhaust face during that test. The latter value was therefore
considered a data outlier. Variability in the particulate profile at the exhaust face may be
attributed to the variety of paints used, and the numbers and sizes of the objects painted.
49
-------
4 -
ch
E 3
o
I
o
o
2-
1 -
—n— Exhaust face
—O-- Intake face
Intake data represent
1/2 MDL
o -o —o
5 10
Height from the floor, ft
15
Figure 23. Measured Concentrations of Paniculate at the Intake and Exhaust
Faces During Split-flow/Recirculating Ventilation—Test 1.
6-
§
o
3
2 -
—-D— Exhaust face
— -O— Intake face
5 10
Height from the floor, ft
15
Figure 24. Measured Concentrations of Paniculate at the Intake and Exhaust
Faces During Split-flow/Recirculating Ventilation—Test 2.
50
-------
5-\
4 -
V
2 -
1 -
•Q— Exhaust face
O— Intake face
Intake data represent
1/2 MDL
o —o o
5 10
Height from the floor, ft
15
Figure 25. Measured Concentrations of Paniculate at the Intake and Exhaust
Faces During Split-flow/Recirculating Ventilation—Test 3.
15 -i
!
—U— Exhaust face
—O" Intake face
Intake data represent
1/2 MDL
n O -o
5 10
Height from the floor, ft
15
Figure 26. Measured Concentrations of Paniculate at the Intake and Exhaust
Faces During Split-flow/Recirculating Ventilation—Test 4.
51
-------
I
tf
o
c
0)
o
c
1.0-1
0.8-
0.6-
0.4-
0.2-
0.0
—O--
Exhaust face
Intake face
Intake data represent
1/2 MDL
o———o
5 10
Height from the floor, ft
15
Figure 27. Measured Concentrations of Particulate at the Intake and Exhaust
Faces During Split-flow/Recirculating Ventilation—Test 5.
8-
E H
c
o
5
4-
2-
—[j— Exhaust face
—O— Intake face
Intake data represent
1/2 MDL
o o ——o
5 10
Height from floor, ft
15
Figure 28. Measured Concentrations of Particulate at the Intake and Exhaust
Faces During Split-flow Ventilation—Test 1.
52
-------
30 n
20-
E
c
o
10-
Exhaust face
Intake face
Intake data represent
1/2 MDL
5 10
Height from floor, ft
15
Figure 29. Measured Concentrations of Paniculate at the Intake and Exhaust
Faces During Split-flow Ventilation—Test 2.
A comparison of paniculate Tests 2 and 5 illustrates the dependence of the exhaust
face concentration profile on the configuration and orientation of the object. Both tests were
conducted during primer painting. Test 2 was conducted during the painting of an 8-foot-high
bowser. Test 5 was conducted during the painting of seven concave Quick Engine Change
(QEC) panels. The panels were placed on two tables in the center of the booth. The tables
were approximately 2.5 feet high and the QEC panels were about 6 inches in height. Comparing
the exhaust face profiles in Figures 24 and 27 shows that a higher concentration of particulate
was observed during the painting of the bowser. The irregular shape of the bowser made it
difficult to paint without significant overspray, whereas applying an even layer of paint to the QEC
panels was easier due to their relatively flat shape. The height of the bowser is also evident from
Figure 24; particulate was emitted higher up in the booth.
Booth 2, the tested booth, was equipped with two sets of particulate filters, one at the
exhaust face (downstream of the exhaust face sampling locations) and one at the booth intake.
Because the exhaust face measurements were obtained upstream of the exhaust face particulate
filters, the results do not affect the practical use of split-flow/recirculating ventilation, even for
large objects. The results indicate that split-flow/recirculating ventilation does not affect the
particulate concentration in the booth. All but one of the intake samples were observed to be
less than the MDL.
3. Metals
Five sets of metals tests were conducted in the combined split-flow/recirculating
ventilation mode. No metals tests were conducted in the split-flow mode. The samples were
analyzed for the presence of strontium, chromium, lead, and zinc. Because the primer contains
53
-------
strontium chromate, metals Tests 1 though 4 were conducted during primer coating. As a
background check, metals Test 5 was conducted during topcoat application.
Figures 30 through 34 present the strontium chromate results for the five metals tests.
The analytical method for metals measures strontium and chromium individually rather than total
strontium chromate. Because the strontium and chromium originated from the strontium
chromate in the primer, their measured concentrations were converted into the equivalent
strontium chromate concentration. The figures present the strontium chromate concentration
profile based on, both strontium and chromium test results. The correspondence of the
concentration profiles in each figure suggests that the measured strontium and chromium
originated only from strontium chromate.
The strontium chromate concentration profile at the exhaust face is consistent with
the concentration gradient concept. At heights above the painter and painted objects, the
concentration decreases with increasing height. Strontium chromate concentrations at the intake
were at or near the MDL, 1 to 3 orders of magnitude below those measured at the exhaust face,
suggesting a high removal efficiency at the exhaust face and intake face paniculate filters.
Test 5 (Figure 34) was conducted during polyurethane topcoat application. Because
this topcoat contains no strontium chromate, little or no strontium chromate was expected to be
present, and neither strontium nor chromium was detected in most samples. The vertical axis
scale in Figure 34 is 0 to 7 //g/m3, compared to 0 to 1,200 //g/m3 in Figures 30 and 31, 0 to
600 //g/nrr in Figure 32, and 0 to 2,000 //g/m3 in Figure 33.
The lead determination results are presented in Figures 35 through 39, and the zinc
determination results in Figures 40 through 44. Because no lead or zinc was observed in the
baseline test series, it is suspected that their presence in the postmodification test series resulted
from nearby sanding operations or from the ducting modifications. The ducting contains welded
galvanized steel, which might contain zinc, chromium, lead, nickel, and molybdenum
(References 14 and 15). The lead PEL is 100 #g/m3; the maximum exhaust face concentration
was 21 //g/m3. The zinc PEL is 1,000//g/m ; the maximum exhaust face concentration was
176 //g/rrr. The concentration patterns for both species appear essentially random; they do not
show the same characteristic concentration pattern at the exhaust and intake faces as the other
measured parameters.
4. Isocyanates
The isocyanate method yields concentration data for MDI, TDI, and HDI. HDI, a
component of the polyurethane topcoat, was detected during topcoat application. The other
isocyanate compounds were neither detected nor listed in the MSDSs. Isocyanate Tests 1
through 4 were conducted during topcoat application; Test 5 was conducted during primer
painting as a background check.
Figures 45 through 48 show the concentrations of HDI measured at the intake and
exhaust faces during isocyanate Tests 1 through 4. All measurements less than 4.5 //g/m3
correspond to one-half the MDL, which varied from test to test due to different collection times.
HDI was not detected in any Test 5 samples.
54
-------
I
1200-1
1000-
800-
§
f 600
O 400-
200
—Q— Exhaust face, based on Cr
—•— Exhaust face, based on Sr
—O— Intake face, based on Cr
— ••— Intake face, based on Sr
5 10
Height from floor, ft
15
Figure 30. Concentrations of Strontium Chromate Measured at
the Intake and Exhaust Faces—Test 1.
1200 n
1000 -
800 -
c
I 600
9
o
c
O 400
200-
—Q— Exhaust face, based on Cr
—•— Exhaust face, based on Sr
—O— Intake face, based on Cr
—••— Intake face, based on Sr
5 10
Height from floor, ft
15
Figure 31. Concentrations of Strontium Chromate Measured at
the Intake and Exhaust Faces—Test 2.
55
-------
600 n
500 -
400-
3.
C
| 300-
1
u
c
3 200
100
—D— Exhaust face, based on Cr
—•— Exhaust face, based on Sr
—O— Intake face, based on Cr
— ••— Intake face, based on Sr
"fJ
5 10
Height from floor, ft
15
Figure 32. Concentrations of Strontium Chromate Measured at
the Intake and Exhaust Faces—Test 3.
2000-
1500-
"I
e"
I 1000
I
u
c
o
U
500-
—D— Exhaust face, based on Cr
—•— Exhaust face, based on Sr
—O" Intake face, based on Cr
— ••— Intake face, based on Sr
5 10
Height from floor, ft
15
Figure 33. Concentrations of Strontium Chromate Measured at
. the Intake and Exhaust Faces—Test 4.
56
-------
c
o
•&
£
7-\
6-
5-
4 -
3-
2-
1 -
Exhaust face, based on Cr
Exhaust face, based on Sr
Intake face, based on Cr
Intake face, based on Sr
5 10
Height from floor, ft
15
Figure 34. Concentrations of Strontium Chromate Measured at
the Intake and Exhaust Faces—Test 5.
c
o
I 1-
—D— Exhaust face
—O— Intake face
O O—-E
5 10
Height from floor, ft
15
Figure 35. Concentrations of Lead at the Intake and Exhaust Faces—Test 1.
57
-------
0.4 i
0.3-
1 o,
I
o
O
0.1 -
0.0
—CD— Exhaust face
—O— Intake face
o -o—
5 10
Height from floor, ft
15
Figure 36. Concentrations of Lead at the Intake and Exhaust Faces—Test 2.
12 -[
10-
I
c
o
O
8-
4 -
2-
10
Height from floor, ft
-Q— Exhaust face
O— Intake face
15
Figure 37. Concentrations of Lead at the Intake and Exhaust Faces—Test 3.
58
-------
0.6 -i
0.5-
n 0.4-
O)
3.
1 0.3-
8
I 0.2-
0.1 -
0.0
O'
—D— Exhaust face
— O— Intake face
5 10
Height from floor, ft
15
Figure 38. Concentrations of Lead at the Intake and Exhaust Faces—Test 4.
0.3 n
0.2-
3.
O
1
O
c
0.1 -
0.0
—D— Exhaust face
--O— Intake face
5 10
Height from floor, ft
15
Figure 39. Concentrations of Lead at the Intake and Exhaust Faces—Test 5.
59
-------
10 n
8-
e
o
£
6 -
4 -
2-
—D— Exhaust face
—O— Intake face
5 . 10
Height from floor, ft
15
Figure 40. Concentrations of Zinc at the Intake and Exhaust Faces—Test 1.
14 -i
12-
10-
1 ,
* 8H
£
o
c
o
O
—D— Exhaust face
—O— Intake face
5 10
Height from floor, ft
15
Figure 41. Concentrations of Zinc at the Intake and Exhaust Faces—Test 2.
60
-------
60 n
50-
40-
f 30 H
O 20-
10-
—D— Exhaust face
—O— Intake face
5 10
Height from floor, ft
15
Figure 42. Concentrations of Zinc at the Intake and Exhaust Faces—Test 3.
§
S
14-]
12-
10-
8-
6-
4 -
2-
—D— Exhaust face
—O— Intake face
5 10 .
Height from floor, ft
15
Figure 43. Concentrations of Zinc at the Intake and Exhaust Faces—Test 4.
61
-------
25 -i
20-
c
o
10-
5-
—D— Exhaust face
—O— I make face
5 10
Height from floor, ft
15
Figure 44. Concentrations of Zinc at the Intake and Exhaust Faces—Test 5.
4 -
3-
o
1
I
O
o
—D— Exhaust face
— O— Intake face
5 10
Height from floor, ft
15
Figure 45. Concentrations of HDI Measured at the Intake and Exhaust Faces—Test 1.
62
-------
7 -\
6-
5 -
o
8
o
O
3-
—D— Exhaust face
—O— Intake face
5 10
Height from floor, ft
15
Figure 46. Concentrations of HDI Measured at the Intake and Exhaust Faces—Test 2.
5-
4-
o
1
2-
1 •
O— "E
Exhaust face
—O— Intake face
r— 1 1—
5 10
Height from floor, ft
—i
15
Figure 47. Concentrations of HDI Measured at the Intake and Exhaust Faces—Test 3.
63
-------
g
u
c
o
U
8-
6-
= 4 -
2-
—D— Exhaust face
— O— Intake face
5 10
Height from floor, ft
15
Figure 48. Concentrations of HDI Measured at the Intake and Exhaust Faces—Test 4.
F. RESULTS OF DUCT MEASUREMENTS
The duct measurement results are described below for both the split-flow and the
combined split-flow/recirculating ventilation tests. Spreadsheets containing the reduced data are
presented in Volume II, Appendix G. Each compound not detected is assumed to be present
at one-half the MDL
1. Organic Compounds
Measurements of organics in the two ducts were performed throughout the test
program, during all split-flow and combined split-flow/recirculating ventilation tests.
a. Integrated Sampling
Integrated results for individual organic species from the NIOSH Method 1300
tests are provided in Volume II, Appendix G, along with sampling times and volumes. Table 19
lists the average concentration of total measured organics, which consisted primarily of MEK,
MIBK, toluene, and butyl acetate.
The results of organic Tests 1 through 4 in split-flow/recirculating ventilation mode
indicate that the average total organic concentration exiting through the split-flow duct (lower
plenum) was greater than the concentration exiting the recirculation duct (upper plenum),
confirming the top-to-bottom concentration gradient. During Tests 5 and 6, and split-flow Test 1,
the average concentration in the split-flow duct was less than or equal to the concentration
measured in the recirculation duct. In these three cases, topcoat paint was applied to objects
64
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TABLE 19. AVERAGE CONCENTRATIONS OF TOTAL ORGANIC SPECIES MEASURED IN
THE SPLIT-FLOW AND RECIRCULATION DUCTS USING NIOSH METHOD 1300.
Test
Average Organics Concentration
(mg/m3)
Split-flow Duct
Recirculation Duct
Split-flow/Recirculating Ventilation
Organics Test 1
Organics Test 2
Organics Test 3
Organics Test 4
Organics Test 5
Organics Test 6
12
15
41
8.4
13
27
3.5
6.8
31
2.5
20
27
Split-flow Ventilation
Organics Test 1
5.0
5.2
with heights of 8.5 feet, representing 60 percent of the total booth height. However, in every
instance, the concentrations remained significantly lower than the computed STEL of 350 ppm
for a mixture of paint components.
b. Continuous Emission Monitoring Results
OEM was conducted in both the split-flow duct and the recirculation duct. Two
OEM methods were employed, BAAQMD Method ST-7 and EPA Method 25A.
BAAQMD Method ST-7 is not reliable when background CO2 constitutes more
than 85 percent, on a molar basis, of the total carbon in a sample. Because the TOC
concentration measured in the ducts averaged between 10 and 40 ppm, the background CO2,
typically 370 to 400 ppm, averaged 85 to 98 percent of the total sample. The method also
indicates that the minimum sensitivity of the detector is 2 percent of full scale; measured TOC
ranged from 1 to 500 ppm, corresponding to less than 1 percent up to 30 percent of full scale.
Due to the high background CO2 and the corresponding low signal-to-noise ratio
observed during Method ST-7 testing, EPA Method 25A provided the more reliable data in this
test program.
Figures 49 and 50 present representative outputs from Method 25A for the
split-flow/recirculating ventilation tests. Figure 49 compares Method 25A results for the split-flow
and recirculation ducts during one of the solvent-based topcoat painting tests. Figure 50
compares split-flow and recirculation duct concentrations during primer painting. Both figures
show an emission peak corresponding to the painter's cleaning the paint spray gun with MEK.
Comparing the two figures shows that polyurethane topcoat has a higher VOC content than the
epoxy primer. This is consistent with the information reported in the respective MSDSs.
65
-------
ppm
140
120
100
80
60
40
20
Gun-cleaning
826 830 834 838 842 846 850 854 858 902 906 910 914 918 922 926 930 934 938 942
time
Recirc. Duct Split-Flow Duct
Figure 49. Representative Results from Continuous Emission
Monitoring by EPA Method 25A—Topcoat Painting.
1336 1342 1348 1354 1400 1406 1412 1418 1424 1430 1436 1442
1339 1345 1351 1357 1403 1409 1415 1421 1427 1433 1439 1445
time
Recirc. Duct Split-Flow Duct
Figure 50. Representative Results from Continuous Emission
Monitoring by EPA Method 25A—Primer Painting.
66
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Figures 49 and 50 also indicate that the average concentration in both the
recirculation and split-flow ducts is far below the pre-set booth concentration limit of 350 ppm.
This is reaffirmed from the feedback FID results for the booth intake (site F, Figure 14).
The concentration of organics in the intake air was monitored using Method 25A
downstream of the fresh air intake point. The FID used in this method was connected to the
feedback control loop, a necessary condition required by MQ AFLC/SGBE to ensure against
possible overexposure from organics in the recirculated air. Data recovered from the feedback
FID indicate that the test conditions did not exceed safety standards.
Figure 51 is a sample strip chart indicating typical Method 25A results for split-flow
ventilation (i.e., no recirculation). In this test, both epoxy primer and polyurethane topcoat were
applied, and the paint spray gun cleaning technique was different from that used during the
split-flow/recirculating ventilation tests.
The practice of solvent recovery during paint spray gun cleaning significantly
affected the solvent concentrations observed in the ducts. In Figures 49 and 50, a distinct VOC
peak appears during the gun-cleaning process because the painter followed the common
practice of discharging the solvent directly into the air. In the test represented by Figure 51, the
gun-cleaning occurred at about 12:06 p.m. No gun-cleaning peak appears at that time point in
Figure 51 because the painter filled the gun with MEK and sprayed it directly into a solvent waste
container in the booth. Adopting the simple practice of discharging gun-cleaning VOCs into a
recovery container would cost only the price of disposal of the solvents recovered, and would
decrease the total VOC emissions from the installation by about 1 pound per shin worked by
each painter.
ppm
30
25
20
15
10
5
to
o
o
I.
-------
c. Solvent Mass Balance Results
A mass balance was performed for every sampling event. BAAQMD Method ST-7
and EPA Method 25A results, and the paint MSDS information, were used to calculate the mass
of VOCs released to the atmosphere during painting. The mass of VOCs was converted into an
equivalent mass of carbon or propane to allow direct comparisons to the Method ST-7 and
Method 25A results.
The mass balance results are presented in Table 20. The entire drying cycle
typically was not measured; therefore, the solvent mass measured in the split-flow duct was less
than the solvent mass released during painting. However, the results indicate that, during the
test period, an average of 70 to 80 percent of the VOCs released from the painting operations
were exhausted to the split-flow duct during split-flow/recirculating ventilation. Thus, in this
mode, 70 to 80 percent of the VOCs would be discharged to a control device. In addition, if the
object remains in the booth until dry, the percentage of VOCs captured and discharged to the
VOC control device would approach 100 percent.
2. Paniculate
Table 21 compares the concentrations of paniculate measured from the split-flow and
recirculation ducts during all tests. In 11 of the 19 tests, the paniculate concentration measured
in the split-flow duct was greater than that measured in the recirculation duct. The paniculate
measurements in the ducts were obtained downstream of the exhaust face paniculate filters.
Downstream of paniculate collection, the split-flow duct and recirculation duct paniculate
concentrations would not be expected to differ significantly. Accordingly, the average
concentration in both ducts over the 16 split-flow/recirculating ventilation tests was 3.3 mg/rrr.
The probe wash of several samples spilled in transport. In such cases, the analytical
results were increased by the volume ratio of total initially collected solvent and the final analyzed
solvent volume, to account for the lost sample.
3. Metals
Concentrations of metals in the split-flow and recirculation ducts are presented in
Table 22. Concentrations of chromium in the ducts were greater than expected when based on
the strontium results. In addition, Test 5 was conducted in the absence of primer containing
strontium chromate; however, chromium was detected. Strontium was not detected, indicating
that the source of chromium was not strontium chromate. Similarly, the concentrations of
chromium, lead, and zinc were higher in the recirculation duct than in the split-flow duct. As with
the exhaust and intake face metals results, these results may be due to the presence of zinc in
the welding material (Reference 14), and the presence of chromium, lead, and zinc in the
galvanized steel (Reference 15) that was used to construct the split-flow transition manifold. As
the welding material is on the outside of the split-flow duct but on the inside of the recirculation
duct, the recirculation duct would be expected to release more stray metal dust than the
split-flow duct.
4. Isocyanates
Measurements of HDI were made in the two ducts. The results are tabulated in
Table 23. The results indicate that isocyanates tend to exit from the lower portion of the exhaust
plenum, confirming the concentration gradient phenomenon upon which split-flow ventilation is
68
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TABLE 20. SOLVENT MASS BALANCE RESULTS.
Test
Mass of Carbon
Released into
Booth
(paint use data)
(9)
Mass of Carbon Measured
in the Split-flow Duct
BAAQMD
Method ST-7
(9)
EPA
Method 25A
(9)
Percent of Solvents
Released that are
Accounted for
BAAQMD
Method ST-7
EPA
Method 25A
Spltt-flow/Recirculating Ventilation
Organics Test 2
Organics Test 3
Organics Test 4
Organics Test 5
Organics Test 6
Paniculate Test 1
Paniculate Test 2
Paniculate Test 3
Paniculate Test 4b
Paniculate Test 5
Isocyanates Test 1
Isocyanates Test 2
Isocyanates Test 3
Isocyanates Test 4
Isocyanates Test 5
Metals Test 1
Metals Test 2
Metals Test 3
Metals Test 4b
Metals Test 5
460
601
272
862
588
416
306
355
150
274
579
575
326
356
101
378
146
96
306
765
65
208
19
631
9
466
290
224
61
232
447
545
315
297
2
298
63
67
262
834
399
594
242
555
498
379
131
131
31
77
487
359
243
347
72
179
41
50
91
669
14"
35
7"
73
2"
112
95
63
41 b
85
77
95
96
84
2"
79
43
69
86"
109
87
99
89
64
85
91
43
37
21b
28
84
62
74
98
71
47
28
52
30"
88
Split-flow Ventilation
Organics Test 1
Paniculate Test 1
Paniculate Test 2
616
373
333
334
372
387
323
543
426
54
100
116
52
146
128
"Method ST-7 equipment faulty.
bDue to power loss or electrical Interference, booth convened to single-pass; invalid test.
69
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TABLE 21. CONCENTRATIONS OF PARTICULATE MEASURED IN THE SPLIT-FLOW
AND RECIRCULATION DUCTS.
Test
Split-flow Duct
Filter
(mg/m3)
Probe
Wash
(mg/m3)
Total
(mg/m3)
Recirculation Duct
Filter
(mg/m3)
Probe
Wash
(mg/m3)
Total
(mg/m3)
Split-flow/Recirculating Ventilation
Organics Test 1
Organics Test 2
Organics Test 3
Organics Test 4
Participate Test 1
Participate Test 2
Paniculate Test 3
Isocyanates Test 1
Organics Test 5
Participate Test 4
Isocyanates Test 2
Isocyanates Test 3
Particulate Test 5
Isocyanates Test 4
Isocyanates Test 5
Organics Test 6
9.8
2.3
NDa
ND
0.4
0.5
0.1
ND
ND
0.5
1.4
0.9
3.5
0.6
ND
ND
1.2
3.9
1.9
6.2
1.8
ND
2.9
2.5
3.7
1.6
1.4
0.1
2.6
1.2
ND
1-4
10.9
6.2
1.9
6.2
2.2
0.5
3.0
2.5
3.7
2.1
2.8
1.1
6.2
1.8
0.0
1.4
1.5
1.0
1.2
0.5
0.6
0.9
0.1
0.5
0.5
0.7
0.7
1.3
1.0
1.2
0.2
0.64
2.0
2.2
3.7
PCb
14.0
PC
1.4
1.6
1.9
1.9
PC
ND
3.7
ND
1.3
2.2
2.1
2.7
0.02
3.5
3.2
4.8
14.5
2.0
2.4
2.0
2.4
0.5
4.4
0.7
2.7
3.2
3.3
2.9
0.66
Split-flow Ventilation
Organics Test 1
Particulate Test 1
Particulate Test 2
ND
NA
0.9
6.3
13.7
ND
6.3
13.7
0.9
0.5
2.3
N.A.C
4.7
PC
0.8
2.0
5.2
3.1
2.0
3ND = Not detected. The final sample weight was equal to or less than the initial
sample weight.
bPC = Paint chips observed in probe wash. Chips may have originated from sampling
apparatus.
CN.A. = Not available. No final sample weight was obtained.
70
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TABLE 22. CONCENTRATIONS OF METALS MEASURED IN THE SPLIT-FLOW AND
RECIRCULATION DUCTS.
Test
Metals Test 1
Metals Test 2
Metals Test 3
Metals Test 4
Metals Test 5
Concentration U/g/m')
Lead
Split-flow
Duct
<0.3"
<0.2
<0.2
<0.2
<0.2
Recirc.
Duct
1.8
<0.2
13
<0.2
4.0
Zinc
Split-flow
Duct
29
77
11
19
37
Recirc.
Duct
96
47
114
43
40
Strontium
Split-flow
Duct
14
12
5.5
12
0.7
Recirc.
Duct
11
9.3
5.4
11
0.5
Chromium
Split-flow
Duct
23
27
8.0
16
12
Recirc.
Duct
63
35
84
33
25
< = Compound not detected. Values listed are one-half the MDL
TABLE 23. CONCENTRATIONS OF HDI IN THE SPLIT-FLOW AND
RECIRCULATION DUCTS.
Test
Isocyanates Test 1
Isocyanates Test 2
Isocyanates Test 3
Isocyanates Test 4
Isocyanates Test 5
HDI Concentration G/g/m3)
Split-flow Duct
17
33
9.4
19
<4.0
Recirculation Duct
17
<3.3a
<3.6
<3.8
<3.9
a< = Compound not detected. Values listed are one-half the
MDL.
based. Test 1, in which the concentrations in the two ducts were essentially equal, was
conducted during the application of polyurethane topcoat to the 7.5-foot-high comfort pallet. The
average concentration of 17 //g/nrr is less than half of the 40 //g/m3 PEL for HDI.
G.
RESULTS OF MEASUREMENTS AT THE PAINTER
The measurement results in the vicinity of the painter are described below for both the
split-flow and the combined split-flow/recirculating ventilation tests. Spreadsheets containing the
reduced data are presented in Volume II, Appendix G. Each compound not detected is assumed
to be present at one-half the MDL
71
-------
1. Organic Compounds
The organic concentrations measured outside and inside the painter's respirator hood
are presented in Tables 24 and 25, respectively. The results affirm the prediction that the mode
of ventilation makes a relatively minor contribution to the net concentration of toxicants in the
vicinity of the painter.
2. Paniculate
Table 26 presents the concentrations of paniculate measured in the vicinity of the
painter. Particulate was not detected inside the painter's respirator in any of the tests. The
results outside the painter's respirator ranged from 0.5 to 41 mg/m3.
3. Metals
The concentrations of metals detected outside and inside the painter's respirator are
presented in Tables 27 and 28, respectively. The concentrations observed outside the respirator
were significantly greater than that detected inside it. Metals detected inside the respirator hood
were likely due to leakage into the hood, which is loose-fining.
4. Isocyanates
The concentrations of HDI measured at the painter, outside and inside the painter's
respirator, are presented in Table 29. All isocyanate tests were conducted in the split-
flow/recirculating ventilation mode. Test 1, in which the HDI concentration outside the respirator
was 280 //g/m3, occurred during the application of topcoat in the inside of the comfort pallet.
This concentration was caused by the airflow restrictions in the enclosed space, and was
unrelated to the mode of booth ventilation.
72
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TABLE 24. CONCENTRATIONS OF ORGANICS OUTSIDE THE PAINTER'S
RESPIRATOR.
Test
Concentration (mg/m3)
MEK
MIBK
Toluene
Ethyl-
benzene
Butyl
Acetate
Xylenes
Total
Split-flow/Recirculating Ventilation
Organics Test 1
Organics Test 2
Organics Test 3
Organics Test 4
Organics Test 5
Organics Test 6
0.4
11.5
2.7
<0.2
8.6
(b)
21.8
6.9
4.7
<0.17
62.7
(b)
2.3
3.8
<0.1
<0.2
12
(b)
<0.1a
<0.1
<0.12
<0.21
1.1
(b)
<0.1
1.1
1.2
<0.2
17.3
(b)
0.2
<0.3
<0.35
<0.6
1.7
(b)
25
24
9.2
<1.6
103
(b)
Split-flow Ventilation
Organics Test 1
0.4
3.2
0.4
0.2
1.9
0.3
6.4
a< = Compound not detected. Values listed are one-half the MDL
bThe sample pump stopped and no sample was collected.
TABLE 25. CONCENTRATIONS OF ORGANICS INSIDE THE PAINTER'S RESPIRATOR.
Test
Concentration (mg/m3)
MEK
MIBK
Toluene
Ethyl-
benzene
Butyl
Acetate
Xylenes
Total
Split-flow/Recirculating Ventilation
Organics Test 1
Organics Test 2
Organics Test 3
Organics Test 4
Organics Test 5
Organics Test 6
<0.1a
0.2
(b)
(b)
(b)
<0.09
<0.08
<0.1
(b)
(b)
(b)
1.7
<0.09
<0.1
(b)
(b)
(b)
5.9
<0.09
<0.1
(b)
(b)
(b)
<0.09
<0.09
<0.1
(b)
(b)
(b)
0.5
<0.29
<0.3
(b)
(b)
(b)
<0.29
<0.7
<0.9
(b)
(b)
(b)
8.6
Split-flow Ventilation
Organics Test 1
<0.08
<0.07
0.5
0.2
0.5
<0.27
1.6
a< = Compound not detected. Values listed are one-half the MDL.
3The sample pump stopped and no sample was collected.
73
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TABLE 26. PARTICULATE CONCENTRATIONS MEASURED IN THE VICINITY
OF THE PAINTER.
Test
Particulate Concentration (mg/m3)
Outside Respirator
Inside Respirator
Split-flow/Recirculating Ventilation
Paniculate Test 1
Particulate Test 2
Particulate Test 3
Particulate Test 4
Particulate Test 5
41
0.9
13
14
0.5
<0.40a
<0.25
<0.25
<0.24
<0.25
Split-flow Ventilation
Particulate Test 1
Particulate Test 2
<0.25
10
<0.25
3.0
= Compound not detected. Values listed are one-half the MDL.
TABLE 27. CONCENTRATIONS OF METALS OUTSIDE THE PAINTER'S RESPIRATOR.
Test
Concentration fr/g/m3)
Lead
Zinc
Strontium
Chromium
Split-flow/Recirculating Ventilation
Metals Test 1
Metals Test 2
Metals Test 3
Metals Test 4
Metals Test 5
<0.3a
0.6
0.6
0.4
<0.19
4.6
9.1
20
1.6
3.2
380
1,070
110
680
5.0
267b
610
68
390
3.5
a< = Compound not detected. Values listed are one-half the MDL.
b Average of 2 samples.
74
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TABLE 28. CONCENTRATIONS OF METALS INSIDE THE PAINTER'S RESPIRATOR.
Test
Concentration fr/g/m3)
Lead
Zinc
Strontium
Chromium
Split-flow/Recirculating Ventilation
Metals Test 1
Metals Test 2
Metals Test 3
Metals Test 4
Metals Test 5
<0.3a
<0.2
<0.2
<0.16
<0.19
3.4
2.0
15
1.7
2.9
50
41
<0.8
70
<0.76
54b
24
6.8
42
<0.76
3< = Compound not detected. Values listed are one-half the MDL.
3Average of 2 samples.
TABLE 29. CONCENTRATIONS OF HDI AT THE PAINTER'S BREATHING ZONE.
Test
Concentration of HDI d/g/m3)
Outside Respirator
Inside Respirator
Split-flow/Recirculating Ventilation
Isocyanates Test 1
Isocyanates Test 2
Isocyanates Test 3
Isocyanates Test 4
Isocyanates Test 5
280
44
17
16
3.6
3.4
3.0
3.3
<0.41a
3.6
= Compound not detected. Value listed is one-half the MDL.
75
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SECTION VI
INDUSTRIAL HYGIENE EVALUATION
The following section was prepared by Clayton Environmental Consultants, Inc. (Clayton)
and contains discussion of industrial hygiene issues associated with recirculation of paint booth
air.
A. OBJECTIVE
The objective of this program was to demonstrate that split-flow and recirculating
ventilation, individually and in combination, are safe and cost-effective methods to reduce paint
spray booth exhaust flow rates and thus lower the cost of controlling VOC emissions. This
demonstration was conducted at Paint Spray Booth 2, Building 845, Travis AFB, in Fairfield,
California. The study was designed to show that paint booth air could be recirculated without
creating a safety hazard or an atmosphere at the intake face exceeding the Air Force's standards
for airborne contaminants in a worker's breathing zone.
B. APPROACH
To achieve the project objective, two test series were conducted: (1) baseline, and
(2) combined split-flow/recirculating ventilation. The baseline test series characterized the
distribution of toxic pollutants at the exhaust face and in the exhaust duct of Booth No. 2. These
results were used to locate the split position and the recirculation rate for the split-
flow/recirculating ventilation test series. These data and the test plan for the second set of tests
were reviewed by HQ AFLC/SGBE before approval was given to proceed with the recirculation
tests.
Prior to the second test series, the duct work in Booth No. 2 was reconfigured to separate
exhaust streams from the top and bottom of the booth (split-flow) and to return the upper
exhaust stream to the intake plenum for recirculation through the booth. The split-flow
recirculating ventilation test series demonstrated the feasibility of flow reduction to enhance the
economics of VOC emissions control. During this test series, several split-flow tests were also
conducted to verify that split-flow ventilation by itself improves the economics of VOC emissions
control, and that the ventilation system was designed correctly. The results of the split-flow/
recirculating ventilation and split-flow tests were also used to evaluate the impact of recirculation
on pollutant concentration profiles in the booth.
For the baseline and split-flow/recirculating ventilation test series, comprehensive
sampling and analysis matrices were developed. Each test matrix included sampling in the
ventilation ducts and in the booth at the exhaust face to measure concentrations of VOCs,
participate, metals, and isocyanates. In-booth sampling identified constituent concentration
profiles at the exhaust face during painting as well as concentrations in the vicinity of the painter.
Duct sampling yielded constituent concentrations in the ventilation streams. Such engineering
parameters as temperature, pressure, and flow rate were also measured.
The purpose of the test program was to determine the effectiveness of the split-flow and
recirculation modifications in typical Air Force painting operations; it was a proof-of-concept study
only. It is recognized that the concentration gradients that occur during painting depend on both
the flow parameters of the ventilation system and the size and orientation of the object painted.
76
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In general, small workplaces (less than 5 feet high) are painted at the Air Force facility targeted
for conversion. Previous studies have demonstrated that, under these conditions, favorable
vertical concentration gradients occur (Reference 4).
In this study, the painter typically painted for 2 hours during each 8-hour workday.
Therefore, the concentrations the painter was exposed to over the entire workday are partial
sums of the concentrations in the booth for 2 hours of each day and background concentration
in the workplace for the remaining 6 hours of each workday. This background concentration was
assumed to be zero. Because painting requires significant preparation time, this estimate of
2 hours of painting time per day, or 10 hours of painting time per week, is considered typical.
Each activity conducted at Travis AFB depended upon prior approval. Details of
proposed activities were sent to Travis AFB and the base Environmental Management (EM)
Office, to expedite approval by the respective fire, safety, and bioenvironmental engineering
authorities before commencement of booth testing or modification activities. In addition, the test
plan was reviewed and approved by HQ AFLC/SGBE.
The strategy for evaluating the effects of recirculation on worker exposure is based on
a comparison of air sampling data outside of the hood and the assigned respirator protection
factor to determine if the calculated TWA exposure is within the applicable exposure standard.
C. STANDARDS AND GUIDEUNES
In the United States, two organizations publish exposure limits for airborne chemicals.
The first is the federal Occupational Safety and Health Administration (OSHA). The OSHA
exposure limits are called Permissible Exposure Limits (PELs) and are codified into Department
of Labor regulations in Title 29 of the Code of Federal Regulations (CFR), Part 1910.1000. These
are the exposure limits that are enforceable by OSHA during inspections of the workplace. The
second organization is the American Conference of Governmental Industrial Hygienists (ACGIH).
The ACGIH publishes recommended exposure limits known as Threshold Limit Values (TLVs).
These limits are intended to be used as guidelines for good practice. Both OSHA standards
(PELs) and ACGIH guidelines (TLVs) for the chemicals involved in this study are listed in
Table 30. The exposure limits referenced are 8-hour time-weighted average (TWA)
concentrations. Other limits such as Short-Term Exposure (STEL) or Ceiling (C) limits are not
addressed because of limitations in the sampling data. Since the PEL and the TLV for the same
chemical can be different, the Air Force/SG policy is to use the more stringent of the two values
when assessing airborne chemical exposures to Air Force personnel.
In January 1989, OSHA revised the 1910.1000 Air Contaminants standards, which
resulted in lower limits for some chemicals and newly established limits for others. However, on
July 7, 1992, the U.S. Court of Appeals for the 11th Circuit vacated and remanded OSHA's
generic rulemaking. The Department of Justice has decided not to fight the ruling. Had the
revised standards remained in effect, exposure limits for several of the target chemicals of this
study would have been lowered. Those proposed limits are also included in Table 30.
The ACGIH updates TLVs each year. Table 30 lists the 1990 TLVs and the 1993 TLVs
for target compounds. Three differences between 1990 and 1993 TLVs relate to this discussion:
• TLV (TWA) for toluene changes from 377 to 188 mg/m3
77
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TABLE 30. OSHA PELS AND ACGIH TLVs FOR TARGET COMPOUNDS (8-HOUR TWA).
Compound
Zinc (As ZnO)
Lead3
Chromium (VI compounds as Cr)
Strontium chromate (As Cr)
HDI
MEK
MIBK
Toluene
n-Butyl acetate
Ethylbenzene
Xylenes
OSHA PEL
(19711
(mg/m3)
15
0.05
0.1 (ceiling)
None
None
590
410
754
710
435
435
OSHA PEL
(Proposed)
(mg/m3)
10
0.05
0.1 (ceiling)
None
None
590
205
375
710
435
435
OSHA PEL
(1990)
(mg/m3)
10
0.15
0.05
None
0.034
590
205
377
713
434
434
ACGIH TLV
(1993)
(mg/m3)
10
0.15 (0.05)b
0.05
0.0005
0.034
590
205
188
713 (95)b
434
434
aAs defined in 29 CFR 1910.1025.
Intended change.
• TLV (TWA) for n-butyl acetate is listed as an "intended change" to 95 mg/m
• TLV (TWA) for strontium chromate was adopted in 1992
When evaluating exposures to mixtures of chemicals, both OSHA and the ACGIH provide
guidance for assessing exposures. When dealing with these mixtures, the combined effect,
rather than that of either individually, should be given primary consideration. In the absence of
information to the contrary, the effects of the different hazards should be considered as additive.
If the result of the following equation exceeds unity, then the exposure limit of the mixture should
be considered as being exceeded.
(18)
where:
E = The exposure index for the mixture
78
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Cf = The 8-hour TWA concentration of contaminant /
LI = The PEL or TLV for substance /
TWA concentrations are based on monitoring during an 8-hour work shift.
The above equation should be used to assess exposures to mixtures of chemicals only
when there is good reason to believe that the chief effects of the different chemicals are in fact
additive. Chemicals having dissimilar toxicologic effects or having effects considered synergistic
when presented in combination should be evaluated separately.
Chemical exposures encountered during the paint spray operations conducted during this
study can be classified by potential toxicity into three categories:
* Organic solvents
• Metals
• Isocyanates
Because these classes of chemicals have dissimilar toxicologic effects, exposure indices
(E^ were calculated for each category and compared to the criterion exposure index of 0.25
arbitrarily established by HQ AFLC/SGBE for this study.
The specific chemicals are listed in the tables in Volume II, Appendices F and G.
D. PERSONAL PROTECTIVE EQUIPMENT
As outlined by Acurex Environmental, personal protective equipment worn by the painter
during both the baseline and postmodification sampling efforts consisted of Tyvek* coveralls,
gloves, and a hood-type airline respirator (Type C Continuous Flow). The respirator was
Model 20-T, manufactured by the E.D. Bullard Company. The air compressor supplying the
hood was a Model ADP-A-C, also provided by Bullard. Performance data from Bullard indicate
that the compressor can deliver up to 11.7 scfm at approximately 11 psig using a V-20-100ST
hose with 1/2-inch QD couplers. The assigned protection factor of this type of respirator is
1.0001 based on a minimum air flow through the hood of 6 cfm. As indicated by Acurex
Environmental, the painter adjusted the equipment according to his normal routine, and hood
air flow rate and hose pressures were not monitored or recorded.
When interpreting the air sampling data sets for outside (over) and inside (under) the
respirator hood, it is important to note that the Model 20-T hood, according to Bullard, is not
equipped with an inner bib. The persons responsible for sample collection have reported to
Clayton that the sampling medium for under-hood breathing zone collection was attached to the
shoulder near the collar bone. These conditions make it difficult to assume that the air samples
collected under the respirator hood are representative of the painter's breathing zone exposure.
Bullard informed Clayton that the use of a Model 20-TIC hood is typically recommended
for use during spray painting. This model has an inner bib. The use of a hood without an inner
1 Refer to ANSI Standard for Respiratory Protection (Z88.2-1992).
79
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bib could compromise the respirator's protection ability by allowing paint mist and other
contaminants to be introduced under the hood during head movement.
E.
SAMPUNG MATRIX AND METHODS
Samples to represent breathing zone concentrations were collected both inside and
outside of the painter's hood during baseline, split-flow, and combined split-flow/recirculating
ventilation tests. The number of sample sets is summarized in Table 31. Each sample set
represents a pair of inside/outside respirator samples.
Samples were collected by Acurex Environmental's staff. In describing the sampling
geometry, Acurex Environmental stated that, to accomplish painter breathing zone sampling,
they attached two pumps to the painter. Sampling medium was attached to the shoulder, with
one sampler under the hood and the other outside the hood. Based on information provided
to Clayton, supplied-air hoods without inner bibs were used during the collection of all sample
sets. The issue of inner bibs on the supplied-air hoods is discussed in the previous paragraph.
Detailed discussions of the sampling methods for baseline and postmodification testing
are included in Section IV (B) and in Section V (B).
F.
RESULTS OF SAMPLE SET ANALYSIS
Because of the suspect nature of the breathing zone samples collected under the
supplied-air hood, Clayton will not utilize the data for those samples during the analysis of the
effects of recirculation on the exposure hazard to the painter. This decision can be supported
by the fact that review of the data from several sample sets of organic vapor and metals analyses
reveals respirator PFs of less than 10. This is highly suspect since the assigned PFfor supplied-
air continuous-flow hood-type respirators equipped with inner bibs is 1,000, and in most cases
actual PFs are even higher.
The objective of analysis of the air sampling data is to demonstrate that painting under
recirculating ventilation conditions does not exceed the criterion exposure index (E^ value of
0.25 specified by HQ AFLC/SGBE.
Because the breathing zone air sampling data are suspect, the air sampling data
collected outside the respirator hood will be used to calculate the Em for each of the contaminant
categories. As the data were collected outside the respirator hood, they represent the exposure
TABLE 31. AIR SAMPLING MATRIX.
Parameters
Metals
Isocyanates
Organics
Particulate
No. of Baseline
Air Sample Sets
2
2
2
2
No. of Split-flow
Air Sample Sets
0
0
1
2
No. of Split-flow/Recirculating
Ventilation Air Sample Sets
5
5
6
5
80
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without regard for the use of respirators. Clayton calculated another exposure index, Em(PF),
which represents the actual inside-the-respirator breathing zone exposure index. The Em(PF) is
the Em reduced by a factor of 1,000, which is the assigned protection factor for the hood-type
continuous supplied-air respirator with inner bib.
It is important to note that the Assigned Protection Factor table contained in the ANSI
standard does not specify that the PF for hood-type respirators assumes that the respirator is
equipped with an inner bib. Clayton contacted the Chairman of the ANSI Respirator Committee
and requested clarification. The Chairman replied that the ANSI Assigned Protection Factor for
the continuous-flow hood-type respirator was indeed based on a hood equipped with an inner
bib.
The following subsections discuss sampling data collected before and after modification
of the paint booth.
1. Organics
a. Premodification
Results of premodification air sample analyses indicated low concentrations of
each of the five target chemicals. Em values for the two sample sets were 0.07 and 0.04. Data
are presented in Volume II, Appendix F.
b. Postmodification
Analysis of the air samples for the five target chemicals revealed concentrations
below the applicable PELs/TLVs. The average Em for unprotected exposure during the
recirculating ventilation test series was equivalent to the Em exposure during the baseline series.
Postmodification air sampling results are shown in Table 32.
2. Metals
The applicable standard for chromium-containing paint at the time of this study was
the TLV for chromic acid, which was 0.05 mg/m3. As discussed above, the ACGIH adopted a
TLV for strontium chromate in 1992. The discussion below references the chromic acid TLV as
the applicable standard. The extremely low strontium chromate TLV virtually rules out its use in
any recirculating system equipped with a standard filtration system.
a. Premodification
Lead and zinc were below PELs, but strontium chromate was present in
concentrations resulting in potential unprotected TWA exposures above the exposure limit.
However Em(PF) values are within the guideline. Results are outlined in Table 33.
b. Postmodification
Analytic results of air samples collected during recirculating ventilation indicate
exposures to lead and zinc below the applicable 8-hour TWA exposure limits. However,
exposure levels for strontium chromate are an order of magnitude above the TLV. The average
unprotected Em was 1.4, with an Em(PF) of 0.0014 when the protection afforded by the respirator
is factored in. Results of the air sampling are presented in Table 34.
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TABLE 32. POSTMODIFICATION AIR SAMPUNG (8-HOUR TWA) RESULTS AND £_
FOR ORGANICS.
Date
6/16/92
6/17/92
6/17/92
6/18/92
6/25/92
6/30/923
Average
PEL/TLV
MEK
(mg/m3)
0.1000
2.8750
0.6750
0.0986
2.1500
—
1.1800
590
MIBK
(mg/m3)
5.4500
1.7250
1.1750
0.0814
15.6750
—
4.8213
205
Toluene
(mg/m3)
0.5750
0.9500
0.0573
0.0977
4.5750
—
1.2510
188
/7-Butyl
Acetate
(mg/m3)
0.0450
0.2750
0.3000
0.0994
4.3250
—
1.0089
95
Xylenes
(mg/m3)
0.0500
0.1513
0.1851
0.3153
0.4250
—
0.2253
434
Em
0.03
0.02
0.01
0.00
0.15
N.A.b
0.04
NAC
EJPF)
0.00
0.00
0.00
0.00
0.00
N.A.
0.00
NA
aSample void.
bN.A. = Not available.
CNA = Not applicable.
TABLE 33. METALS BASELINE AIR CONCENTRATIONS (8-HOUR TWA).
Date
4/16/91
4/17/91
Average
PEL/TLV
Lead
(mg/m3)
<0.01598b
<0.01563
< 0.01 580
0.05
Zinc
(mg/m3)
<0.01598
< 0.01 563
< 0.01 580
10
Strontium Chromate8
(mg/m3)
0.0440
0.0421
0.0430
0.05
Em
1.20
1.15
1.18
. —
EJW
0.0012
0.0012
0.0012
—
aAs chromium.
b< indicates less than the method detection limit.
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TABLE 34. POSTMODIFICATION AIR SAMPLING (8-HOUR TWA) RESULTS AND Em
FOR METALS.
Date
6/22/92
6/24/92
6/25/92
6/26/92
6/26/92
Average
PEL/TLV
Lead
(mg/m3)
0.00018
0.00015
0.00015
0.00010
0.00013
0.00015
0.0500
Zinc
(mg/m3)
0.0013
0.0023
0.0049
0.0004
0.0008
0.0019
10
Strontium Chromate8
(mg/m3)
0.0772
0.1528
0.0170
0.0981
0.0009
0.0692
0.05
En,
1.54
3.06
0.34
1.96
0.018
1.4
NAb
EJPF)
0.0015
0.00306
0.00034
0.00196
0.00002
0.0014
NA
aAs chromium.
bNA = Not applicable.
3. Isocyanates
a. Premodification
Concentrations of hexamethylene diisocyanate (HDI) for both baseline tests were
below the exposure limit with an average Em of 0.04.
b. Postmodification
Concentrations of HDI for samples collected under recirculating ventilation varied
from 0.0036 to 0.2786 mg/m3. Four of the 8-hour TWA values were above the PEL/TLV of
0.034 mg/m3. The sample collected on 23 June 1992 indicated an HDI concentration of
0.2786 mg/m3, considerably above the remaining sample results, which averaged
0.0203 mg/m3. This result was obtained during painting operations involving the application of
white polyurethane topcoat paint inside a comfort pallet. This data point is not representative
of the normal paint booth environment since it is a space isolated from the air movement in the
booth. This was the only sample set collected during the application of this type of paint.
The average unprotected £ for this sample series was 0.53, with an E (PF)
averaging 0.0005.
G. DISCUSSION
The results of the air sampling data gathered to assess the impact of recirculating
ventilation on the exposure hazard to the painter indicate that exposures to organics and HDI
were within established exposure limits with or without the use of a respirator.
83
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In general, the respiratory protection provided during this study did not provide adequate
protection, based on results of air samples collected inside the respirator hood (see Volume II,
Appendices F and G). As we have explained, such appears to be the result of the use of a
hood-type respirator without an inner bib. The ANSI Standard for Respiratory Protection (Z88.2-
1992) lists an assigned protection factor of 1,000 for a hood-type (with inner bib) continuous-flow
supplied-air respirator.
Unprotected exposures to lead, zinc, and strontium chromate were in excess of the
equivalent exposure index (Em) value of 1.0 for both baseline and recirculating test modes.
Strontium chromate levels in the painter's breathing zone were approximately 60 percent higher
during recirculating ventilation than they were in the baseline test series. However, in both
instances, the equivalent exposure index (using the chromium PEL of 0.05 mg/m3 for strontium
chromate exposure) would not be exceeded if a respirator with an assigned PF of 1,000 were
used. The protected exposure indices [Em(PFJ] using the new TLV for strontium chromate were
also within acceptable limits [£m(PFJ less than or equal to 1.0].
H. CONCLUSIONS
When the proper respiratory protection is used, it appears that recirculating ventilation in
the subject paint spray booth did not result in an increase in the concentration of the air
contaminants studied to any degree that might have exceeded the capability of the respiratory
protection provided to maintain the exposures within the exposure index guideline.
Because there can be wide ranges in operating conditions at Air Force facilities, the
effects of adjusting exposure variables such as booth air flow, paint application rates, paint types,
and recirculation rates should be evaluated further.
These conclusions are based on the assumption that the continuous-flow supplied-air
hood-type respirator equipped with inner bib can provide and maintain its assigned protection
factor of 1,000 during all modes of paint application.
Clayton was not involved in the planning or execution of the field or laboratory work
associated with this project. As such, the information and documents supplied to Clayton during
the course of the project were assumed to be complete, true, and correct, and were relied upon
by Clayton Environmental Consultants, Inc.
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SECTION VII
ECONOMIC ANALYSES
A typical VOC emission control device (ECO) can achieve a removal efficiency of at least
95 percent. However, the costs associated with installing and operating a system capable of
processing the total flow volume can be enormous. The use of split-flow, recirculating, or a
combination of split-flow/recirculating ventilation can significantly reduce the cost by reducing
the volume of air that must be treated. Flow reduction will also decrease heating and cooling
costs if the fresh intake air must be heated or cooled. This section discusses the economic
advantages and benefits achievable from the use of one of these flow-reduction technologies in
the control of emissions from paint spray booths.
A. CONTROL TECHNOLOGIES
The EPA handbook, Control Technologies for Hazardous Air Pollutants (Reference 16),
describes the designs and costs of a variety of VOC emission control technologies, including
thermal incineration, catalytic incineration, and carbon adsorption. Because the handbook notes
that carbon adsorption systems may experience difficulty in controlling emission streams
containing ketones, economic assessments were carried out only for thermal incineration and
catalytic incineration. Ketones exothermically polymerize on the carbon bed, clogging the pores
on the carbon surface, thereby reducing the effectiveness of the carbon bed. The paints used
during this study contain up to 25 percent ketones in the form of MEK, MIBK, and methyl
n-propyl ketone; in addition, the paint guns were cleaned with MEK.
The capital and operating costs for thermal and catalytic incinerators operating in
conjunction with flow reduction are discussed below. Similar cost trends are expected for other
treatment devices.
B. COSTS OF BOOTH MODIFICATION
The booth modification costs are based on a booth size equal to Booth 2 at Travis AFB,
with a total booth flow rate of 30,000 cfm. The cost of booth modification differs for split-flow
ventilation and combined split-flow/recirculating ventilation. The cost to design and install ducts
for a split-flow ventilation system is estimated at approximately $20,000 for a 30,000-cfm booth.
This includes the cost to design and install a transition piece in the exhaust plenum to split the
flow into two chambers. The cost for a combined split-flow/recirculating ventilation system is
higher due to costs associated with additional ducting, a sprinkler system, and a feedback FID
control system. The cost to modify a booth to recirculating ventilation is assumed to be the
same as for the combined split-flow/recirculating ventilation modification.
For the emission reduction study conducted at Travis AFB, Booth 2 was modified to
accommodate either split-flow or combined split-flow/recirculating ventilation operation. The cost
to install the ducts, including the purchase and installation of the transition piece, which provided
the actual physical split at the exhaust face, and sprinkler system, was $30,000. This cost does
not include the engineering design of the duct modification and the feedback FID control system;
the total booth modification cost, including the engineering design cost, is estimated at
approximately $90,000.
85
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The design package for this project included a flow transition piece installed in the
exhaust plenum to alleviate speculation regarding the split height. The cost of split-flow and
combined split-flow/recirculating ventilation modifications can be decreased if the exhaust flow
is split by balancing the two exhaust fans rather than by inserting a transition piece in the
exhaust plenum. This option removes the cost of designing and installing the transition piece,
estimated at $30,000. This decreases the combined split-flow/recirculating ventilation
modification cost to approximately $60,000.
C. COST ANALYSIS
The economic analysis described in the EPA handbook requires emission stream data,
such as flow rate, temperature, VOC concentration, and heat content. Table 35 indicates the
parameters used for this analysis. Because the results of this study indicate that with split-
flow/recirculating ventilation the exhaust flow rate may be safely reduced by 90 percent, the cost
analysis was performed for four flow rates: 30,000 cfm (no recirculation), 15,000 cfm (50-percent
recirculation), 7,500 cfm (75-percent recirculation), and 3,000 cfm (90-percent recirculation). The
expected VOC concentration increases as the percent recirculation increases. The heat content
of the exhaust stream was calculated for each VOC concentration.
Tables 36 and 37 list the capital costs and annual operating costs for thermal and
catalytic incineration, respectively. Figures 52,53, and 54 illustrate the dependence on flow rate
of capital, operating, and 10-year-lifetime total emission control costs, respectively. Tables 36
and 37 also indicate the cost reductions achievable over a 10-year equipment lifetime. Sample
economic calculations are provided in Volume II, Appendix I and detailed in Reference 16. For
each of the three recirculation cases, a booth modification cost of $60,000 is included in the total
capital cost. The annual operating costs incorporate capital recovery, equipment depreciation,
and property tax. A 10-year equipment life and 10-percent interest rate are assumed. The
annual expenditures include operation and maintenance, utility (electricity and natural gas) costs,
and catalyst replacement.
D. PAYBACK PERIOD
To determine the length of time for the return-on-investment, the payback period, in
present dollars, for each ECD was calculated by equation (19):
Payback Initial Investment* ($)
period Annual/zed capital saving* + (19)
Annual expenditures for 30,000 scf/n1 -
Annual expenditures for modified scfm*
Initial investment includes the capital and booth modification costs for installing an ECD
in a modified booth. Annualized capital saving is the difference in ECD capital costs between
an unmodified booth and a modified booth, annualized over 10 years. Table 38 lists the payback
periods for thermal and catalytic incineration for 50-, 75-, and 90-percent recirculation. The
results indicate that the payback period for booth modifications is on the order of 1 to 2 years,
depending on the percent recirculation and the ECD selected.
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TABLE 35. EMISSION STREAM ASSUMPTIONS FOR ECONOMIC ANALYSIS.
Parameter
Percent recirculation
Row rate (scfm)
Temperature (°F)
VOC concentration (ppmv)
Exhaust heat content (Btu/scf)
Assumption
0
30,000
77
10
0.03
50
15,000
77
20
0.06
75
7.500
77
40
0.12
90
3,000
77
100
0.3
TABLE 36. CAPITAL, OPERATING, AND LIFETIME COSTS FOR THERMAL INCINERATION.
Percent
Recirculation
0
50
75
90
Flow
Rate
(scfm)
30,000
15,000
7,500
3,000
Costs in Thousands of Dollars
Total Capital
Cost
392
387"
333"
275b
Annual
Operating Cost
383
232
147
91
Cost Over 10-
year Lifetime
6,104
3.697
2,343
1,450
Percent Cost
Reduction
Over 10-year
Lifetime
NAa
39
62
76
•NA = Not applicable.
The capital costs for the split-flow/recirculating ventilation cases incorporate an estimated
cost of $60,000 for the booth modifications.
TABLE 37. CAPITAL, OPERATING, AND LIFETIME COSTS FOR CATALYTIC
INCINERATION.
Percent
Recirculation
0
50
75
90
Flow Rate
(scfm)
30,000
15.000
7,500
3,000
Costs in Thousands of Dollars
Total Capital
Cost
550
471"
368b
270"
Annual
Operating Cost
297
192
127
81
Cost Over 10-
year Lifetime
4.733
3.060
2.024
1,291
Percent Cost
Reduction
Over 10-year
Lifetime
NA'
35
57
73
"NA = Not applicable.
The capital costs for the split-flow/recirculating ventilation cases incorporate an estimated
cost of $60,000 for the booth modifications.
87
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• Thermal Incineration • • Catalytic Incineration
$600
$500
$400 -
2
S
$300
§
$200
$100 -•
$0
H h
0 5000 10000 15000 20000 25000 30000
Flow/rate, dscfm
Figure 52. Capital Costs for Incineration as a Function of Exhaust Flow Rate.
—a—- Thermal Incineration • Catalytic Incineration
$400
$300 --
$200 -
$100
$0
0 5000 10000 15000 20000 25000 30000
Flowrate, dscfm
Figure 53. Annual Operating Costs for Incineration as a Function of Exhaust Flow Rate.
88
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Thermal Incineration • Catalytic Incineration
7000 -i-
6000 --
5000 -
o 4000
3000 --
1000 --
H (-
0 SOOO 10000 tSOOO 20000 25000 30000
Flowrate, dscfm
Figure 54. Total Emission Control Costs for Incineration Over 10 Years.
TABLE 38. PAYBACK PERIODS FOR MODIFYING THE BOOTH FLOW TO COMBINED
SPUT-FLOW/RECIRCULATING VENTILATION.
Percent
Recirculation
50
75
90
Payback Period (years)
Thermal
Incineration
2.5
1.4
0.9
Catalytic
Incineration
4.0
1.8
1.0
89
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SECTION VIII
ENGINEERING CONCLUSIONS AND RECOMMENDATIONS
A. CONCLUSIONS
The data collected in the test efforts and the subsequent engineering evaluation lead to
the following conclusions:
• Reducing the flow rate to the control device is a practical means of lowering VOC
emission control costs for a paint spray booth.
• Constituent concentrations in a paint spray booth are highest in the lower half of the
booth and in the vicinity of the painter.
• Split-flow ventilation has limited practicality as a flow-reduction strategy.
• The optimal split-position height and percent recirculation may be calculated using
mass balance equations and the exhaust concentrations from baseline booth
operations.
• For split-flow ventilation with a VOC control device attached to the high-concentration
stream, the control cost and VOC capture efficiency achieved are driven by the height
of the split.
• Combining split-flow and recirculating ventilation decreases the flow rate to be treated
while substantially increasing the VOC capture efficiency percentage compared with
split-flow ventilation alone.
• The benefit of split-flow combined with recirculating ventilation is that it will, in
general, lower the concentrations of toxicants in the recirculating airstream.
• The pollutant concentrations resulting from combined split-flow/recirculating
ventilation are insignificant in comparison to the concentrations due to local process
conditions.
• An automatic control system can, and should, be installed to monitor the VOC
concentration reentering the booth and convert the booth ventilation mode from
recirculation to conventional single-pass operation if the measured VOC
concentration exceeds a predetermined setpoint.
• Cost-effective elimination of VOC emissions may be achieved with a VOC control
device used in conjunction with each of the following flow-reduction strategies: split-
flow, recirculation, combined split-flow/recirculating ventilation.
• When recirculation of air is used in a paint spray booth, the concentrations of air
contaminants do not appear to increase to a degree that would exceed the capability
of proper respiratory protection.
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B. IMPLEMENTATION RECOMMENDATIONS
Based upon the results of this program, we recommend that the Air Force take the
following actions:
• Work with state and local regulatory agencies and EPA enforcement branches to
identify split-flow and recirculating ventilation technologies falling into the Best
Available Control Technology (BACT), Maximum Achievable Control Technology
(MACT), and Reasonably Available Control Technology (RACT) categories, to reduce
control technology capital and operating costs. •
Consider implementing VOC emission control in conjunction with split-flow or
combined split-flow/recirculating ventilation.
Conduct optimization analyses to develop the optimal flow rate reduction, split-position
height, and in-booth concentration conditions.
• Examine the efficiency of different filters and filter combinations to determine a "best"
particulate removal method to further decrease the levels of metals in the recirculating
stream during primer coating operations.
C. DESIGN RECOMMENDATIONS
1. Steps and Criteria
Recirculating ventilation offers significant decreases in net operating costs for a spray
painting facility by containing part of the risk associated with painting in the paint spray booth
itself. The enabling premise underlying this study and its conclusions and recommendations for
implementation is that proper design, installation, operation, and maintenance can keep the
increase of risk in the painter's breathing zone to an amount so small that it is insignificant as a
change to the background risk encountered under single-pass ventilation of the spray booth. To
ensure that this premise is not invalidated by an inferior installation or inadequate operation and
maintenance practices, we propose that the following criteria be applied during the selection of
candidate sites for installation of this technology:
The facility to be modified must include a climate control system and/or an operational
or imminently planned exhaust emission control device.
The facility to be modified must be capable of maintaining worker exposures at or
below the most stringent limits, such as those specified in 29 CFR 1910.1000, for
chemical constituents of materials present or in use; or, the design for construction
or modification of the facility must be configured to meet these standards before the
recirculation system is activated.
Because the allowable recirculation ratio may be limited by the amount of airborne
particulate matter passing through the booth filters, the actual efficiency of the
particulate control system must either be measured directly or measured for an
equivalent installation operating under nominally identical conditions and workloads.
For flow splitting to be effective, concentration gradients must, on average, be present
in the spraying area, and the concentration gradients from the spray booth
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must be preserved downstream of the exhaust face paniculate control. For example,
a single waterfall control system completely mixes the exhaust, obliterating the
concentration gradient; a dry filter device can maintain such a gradient.
• The ventilation system may be configured so that the organic control device is part
of the recirculated stream if, for instance, it is less expensive to decontaminate and
recirculate close to 100 percent of the air rather than to heat or cool outside air. In
such a case, if an oxidation control technology is to be used to decontaminate the
recirculated air stream, the oxygen content of the recirculated air must be monitored
and supplemented with fresh air as required to maintain breathability, and the
products of destruction must be analyzed upon the system's installation to ensure
that toxic byproducts do not accumulate.
Once a candidate site satisfies the above conditions, the following steps should be
followed to ensure that the increment to risk in the painter's breathing zone is minimized:
• Develop an initial ventilation and control design, which includes an FID or other
quantitative organic-sensing device, as an air quality monitor to initiate conversion
into single-pass ventilation at any time that the airborne organic concentration
exceeds a preselected level.
• If the installation is to be an upgrade of an existing facility, a premodification test
series should be conducted to characterize the performance of the spray facility and
the particulate control system.
• Based on engineering and industrial hygiene analyses of the test series results, or
on best engineering principles if a test series cannot be accomplished, calculate the
maximum achievable recirculation ratio (i.e., the ratio for which the standard to be
applied [29 CFR 1910.1000 or more stringent standards] is exactly met—see below).
Using this ratio, calculate the split height of the split duct to match the unrecirculated
fraction of the exhaust stream.
• As an alternative to a premodification test series, visual observations of the
concentration gradient and a material usage evaluation of VOCs can be used to
estimate the appropriate recirculation ratio. A postmodification test series can be
used to optimize the recirculation ratio and split height, and demonstrate worker
safety.
Note that these steps do not replace any of the steps in the normal design and
approval sequence followed in construction or remodeling programs.
2. Determination of Maximum Attainable Recirculation Ratio
For a recirculating-ventilation-only installation, or for a split-flow/recirculating
ventilation installation whose vertical concentration gradient in the exhaust plane is unknown, the
contribution to the total equivalent exposure (Em ) for each toxic constituent / is C//t/ (see
Section II.A). During recirculation at return rate R, the individual time-weighted average
concentrations in the intake air are equal to the concentrations calculated for an unmodified
booth (Cunmodi) increased by a factor of 1/(!-/?)• By selecting a value for Em, the maximum
attainable recirculation rate becomes:
92
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R . 1 - _L_ £ QsSS* (20)
The value of Cunmodi is a function of the baseline concentration at the exhaust and
the efficiency of the particulate control devices. Therefore, the maximum recirculation rate (ft)
for a site is dependent on the particulate control efficiency. Figure 55 illustrates this dependence,
using the baseline concentration data collected at the test site. The assumptions include a TLV
for strontium chromate of 0.05 mg/m3 and an 8-hour painting shift per work day. Intuitively, the
maximum recirculation rate for organic emissions is independent of the particulate control
efficiency. However, the maximum recirculation rate for metals and isocyanates, the point at
which Em = 1 for each of these constituents, is a direct function of the particulate control
efficiency. The overall maximum recirculation rate for a site must be based on the limiting
constituent. In this example, when the particulate control efficiency is relatively low, the metals
emissions limit the maximum recirculation rate. As the particulate control efficiency is increased,
the organics emerge as the limiting constituents.
If equation (20) is used to determine the maximum acceptable recirculation rate, the
increase in Em at the breathing zone due to recirculation will be insignificant compared with the
£m at the painter due to process conditions. The additional contributions from the painter,
intrinsic to the paint process, result in an Em value greater than 1 at the breathing zone. It is this
intrinsic "paint cloud" that creates the requirement for respiratory equipment. The respiratory
protection factor (PF) of the safety equipment must be sufficient to protect the painter from the
"paint cloud" in the breathing zone. When quantifying the equivalent exposure at the painter,
rather than the equivalent exposure of the intake air, it is appropriate to include in the calculation
the PF for the least-protected person in the booth.
For a system that includes flow splitting, and for which reliable data are available
describing the distribution of contaminants (i.e., the gradient) up the exhaust face, the treatment
detailed in Section II.3.C is applicable. The following calculation is accomplished by iteration on
the ventilation parameters (ft and a):
0 -
(L, R a)
(21)
In performing this iteration, one must keep in mind that R and a are not independent, and that
one must determine a for each value of R to be evaluated. (The right-hand portion of Figure 1
illustrates the calculation graphically; the assumed value of R is 0.50, as indicated by the dashed
line, and the value of a is the ratio of the shaded area to the total area under the h/[C] curve.)
The ACGIH lowered the exposure limit for strontium chromate at about the same time
that this study was conducted. This action effectively eliminates the use of strontium chromate
without respiratory protection because it can be extremely difficult for a ventilation process to
achieve compliant exposure levels. This change in the TLV complicates the interpretation of the
results of this study because particulate filtration efficiency becomes the controlling parameter.
93
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x-x
60 82 84 86 88 90 92 94 96 98 100
Percent Partlculate Removal Efficiency
Figure 55. Dependence of Maximum Projected Reclrculatlon on Percent
Partlculate Removal Efficiency — Reclrculatlng Ventilation.
This also illustrates that a condition noncompliant in a straight-through booth cannot be improved
by recirculation — that is, actual exposures are not decreased, they simply do not increase
measurably if proper design, installation, operation, and maintenance procedures are followed.
As discussed earlier, at the time of the study the ACGIH TLV for hexavalent chromium
was 0.05 mg/m3, for which (given the booth conditions and an assumed 90-percent paniculate
removal efficiency) a recirculation rate of 40 to 50 percent was calculated to be the largest
amount of recirculation that could be applied without exceeding the Em = 0.25 limit on the intake
air imposed by HQ AFLC/SGBE for this study (see Figure 13 in Section IV). After ACGIH
imposed a strontium chromate TLV in 1992 of 0.0005 mg/m3, the same calculation would have
specified 0.5-percent recirculation, which would provide no practical benefit. That strontium
chromate was used in this study is purely a result of the timing of the ACGIH action to lower the
TLV. Proper application of the concept of recirculating ventilation — with or without flow splitting
— requires that the materials used during recirculating ventilation be compliant under ordinary
painting conditions.
Finally, some precedents have been established for the routine use of exhaust
recirculation technology in manned paint facilities. Acceptance by OSHA is stated as a policy in
a letter printed as Appendix A and clearly implied in two documents reproduced in Appendices
B and C. Appendix B is a permanent variance issued by the State of Iowa, acting as OSHA's
agent, allowing the operation of a recirculating paint facility at a John Deere installation. This
action was taken in lieu of amending 29 CFR, which would be a recurrent, major undertaking
required every time a new technology demonstrates performance equal to or better than methods
or standards specified in 29 CFR. Appendix C contains two excerpts from the report of OSHA
inspection number 102597036 (15 April 1991) of BMY Combat Systems Track Vehicles' facility,
94
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which operates a recirculating spray painting booth. Two minor violations are identified in the
painting facilities, without mention of recirculating ventilation. This illustrates the application of
the de minimis principle defined in Appendix A, which spells out the policy of accepting
technology improvements as nominal but uncited (de minimis) violations of 29 CFR
1910.107(d)(9), and identifies 29 CFR 1910.1000 as the applicable regulation.
95
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REFERENCES
1. Code of Federal Regulations. Title 29, Parts 1900 to 1910, July 1991.
2. Ritts, D., Garretson, C., Hyde, C., Lorelli, J., and Wolbach, C.D., Evaluation of Innovative
Volatile Organic Compound and Hazardous Air Pollutant Control Technologies for U.S. Air
Force Paint Spray Booths. EPA-600/2-90-059 (NTIS ADA 242-508), October 1990.
3. Ayer, 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.
4. Ayer, J. and Hyde, C., VOC Emission Reduction Study at the Hill Air Force Base Building
515 Painting Facility. EPA-600/2-90-051 (NTIS ADA 198-092), September 1990.
5. U.S. Department of Patent and Trademark Office, Patent Application Serial
Number 07/609,166, January 21, 1991.
6. Whitfield, J., Howe, G., Pate, B., and Wander, J., "Using a Flame lonization Detector (FID)
to Continuously Measure Toxic Organic Vapors in a Paint Spray Booth," paper
No. 92-139.15, presented at the Air and Waste Management Association 85th Annual
Meeting, Kansas City, MO, June 1992.
7. NIOSH Manual of Analytical Methods. Third Edition. National Institute of Occupational Safety
and Health, NTIS PB86-116266, updated May 1989.
8. Bay Area Air Quality Management District Manual of Procedures. "Standard Test
Procedure 7," updated December 1989.
9. Code of Federal Regulations. Part 60 Appendix A, Test Methods, 1989.
10. OSHA 42 Airborne Di-isocyanate Sampling and Analysis Protocol. Occupational Safety and
Health Administration, Carcinogen and Pesticide Branch, OSHA Analytical Laboratory,
February 1983, unpublished.
11. Test Methods for Evaluating Solid Waste, SW-846 Draft Method 0012, U.S.Environmental
Protection Agency, Office of Solid Waste and Emergency Response, Washington, DC, July
1992.
12. Industrial Ventilation—A Manual of Recommended Practices: Testing of Ventilation Systems.
20th Edition. Chapter 9, American Conference of Governmental Industrial Hygienists, 1988.
13. Coyne, L and Moore, G., Toluene Diisocvanate (TDD Emissions: An Evaluation of
Monitoring Methods and Filtration Substrate for Stacks. 83rd Annual Meeting and Exhibition
of the Air and Waste Management Association, Pittsburgh, PA, June 1990.
14. Code of Federal Regulations. Title 29, Part 1910^252, July 1991, "Welding, Cutting, and
Brazing."
15. Perry, R., and Green, D. Perry's Chemical Engineers' Handbook. Sixth Edition. 1984.
96
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16. Sink, M.K., Handbook: Control Technologies for Hazardous Air Pollutants. EPA/625/6-91/014
(NTIS PB92-141-373),U.S. Environmental Protection Agency, Center for Environmental
Research Information, Cincinnati, OH, June 1991.
(The reverse of this page is blank.)
97
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APPENDIX A
OSHA RUUNG ON PAINT BOOTH EXHAUST GAS RECIRCULATION
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U.S. Department Of Labor Occupational Safety and Health Administration
Washington. D.C. 20210
Reply to the Attention of:
JAN 16
Susan R. Wyatt, Chief
Chemicals and Petroleum Branch
Emission Standards Division
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
Dear Ms. Wyatt:
This is in response to your letter of October 31, 1989,
concerning the Occupational Safety and Health Administration
(OSHA) regulation at 29 CFR 1910.107(d)(9) which prohibits the
recirculation of exhaust air from spray finishing operations.
Please excuse the delay in response.
As you are aware, 29 CFR 1910.107 was adopted from the NFPA 33-
1969, Standard for Spray Finishing Using Flammable and Combust-
ible Materials. The NFPA-33 standard is explicitly a fire and
explosion safety standard. Therefore, the OSHA standard at 29
CFR 1910.107 pertains to the prevention of workplace fire and
explosion hazards and does not pertain to health considerations.
Although the NFPA has updated their standard since the 1969
edition, OSHA has not. As a result, the current NFPA 33-1985,
Spray Application Using Flammable and Combustible Materials,
reflects the most up to date state of the art concerning the
prevention of fire and explosion hazards during spray finishing
operations.
Under an OSHA policy for "de minimis violations", employers are
encouraged to abide by the most current consensus standard
applicable to their operations, rather than with the standard in
affect at the time of the inspection when the employer's action
provides equal or greater employee protection. De minimis
violations are violations of existing OSHA standards which have
no direct or immediate relationship to safety or health. Such
violations of the OSHA standards result in no citation, no
penalty and no required abatement. A copy of the OSHA policy for
de minimis violations is enclosed.
100
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Employers who fully comply with the specifications and require-
ments of the NFPA 33-1989, concerning the recirculation of
exhaust air to an occupied spray booth, would not be cited under
29 CFR 1910*107(0) (9) under the policy for de minimis violations,
However, the quality of the respirable air in the booth must
comply, at a minimum, with the requirements set forth by 29 CFR
1910.1000 which establishes permissible exposure limits (PEL's).
If we may be of further assistance, please contact us.
Sincerely, (
or
f Compliance Programs
101
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OSHA Instruction CPL
Ji'Nl 51989
Office of General Industry Compliance Assistance
€. De Minimis Violations. De minimis violations are violations of standards which
have no direct or immediate relationship to safety or health. Whenever de .
minimis conditions are found during an inspection, they shall be documented in
the same way as any other violation but shall not be included on the citation.
a. Explanation. The criteria for finding a de minimis violation are as follows:
(1) An employer complies with the clear intent of the standard but devi-
ates from its particular requirements in a manner that ha* no direct or
immediate relationship to employee safety or health. These deviations
may involve distance specifications, construction material require-
ments, use of incorrect color, minor variations from recordkeeping,
testing, or inspection regulations, or the like.
EXAMPLES: (a) 29 CFR 1910.27(bXlXii) allows 12 inches as the maxi-
mum distance between ladder rungs. Where the rungs are 13 Inches
apart, the condition is de minimis.
(b) 29 CFR 1910.2S(aX3) requires guarding on all open sides of scaf-
folds. Where employees are tied off with safety belts In lieu of guard-
ing, the intent of the standard is met; and the absence of guarding is
de minimis.
(c) 29 CFR 1910.217(eXlXii) requires that mechanical power presses
be inspected and tested at least weekly. If the machinery is seldom
used, inspection and testing prior to each use is adequate to meet the
Intent of the standard.
(2) An employer complies with a proposed standard or amendment or a
consensus standard rather than with the standard in effect at the time
of the inspection when the employer's action provides equal or greater
employee protection.
(3) An employer's workplace is at the "state of the art" which Is techni-
cally beyond the requirements of the applicable standard and provides
equivalent or more effective employee safety or health protection.
b. Professional Judgment. Maximum professional discretion must be exer-
cised in determining the point at which noncompliance with a standard
constitutes a de minimis violation.
c. Area Director Responsibilities. Area Directors shall ensure that the de
minimis violation meets the criteria set out in B.6.a.
102
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APPENDIX B
PERMANENT VARIANCE ISSUED BY IOWA FOR
A JOHN DEERE RECIRCULATING PAINT FACILITY
103
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02/28/84 12:51 ©819 541 2157
EPA/AEERL/RTP.NC
@1001/004
DEERE & COMPANY
I1EE.HE BtVAO. MOHNr Illinois «IW.
TO. E. J. Pilby, Safety Director, Des Moines
Pmm: E. O. Sh2W, Law
Oale: 10 septentoer 19B4
Variance No. 68 - John Deere Des Koines Works
This is your oojy of the permanent variance grant for operation of the
paint booths.
please post a copy and deliver one to the union.
Applying for and obtaining these variances has been one of ay most
satisfying tasks at Deere & Company.
ECS/bh
Att.
c •»• att C. A. Peterson, Safety
OPTIONAL FOB" M (T 90)
FAX TRANSMITTAL
NSN 7540-01-317-7368 5349-1111
Rionilf
inajf i
?/r/£
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02/28/84 12:52 fj919 541 2157 EPA/AEERL/RTP.NC E)002/004
IOWA BUREAU OF LABOR
OCCUPATIONAL SAFETY AMD HEALTH ADMINISTRATION
In the matter of )
>
John Deere Des lloines Works } Variance No. 68
of Deere fc Company )
I. BACKGROUND
Oo July 3O, 1982. John Deere Dea Iloines Works of Deere &
Company, Highway 415 North, Ankeny, Iowa, made application for
a permanent variance. The application was made pursuant to Iowa
Code section 88.5(3) and 530-5.8(88)IAC and requested a variance
from 530-10.3(8B)IAC, reference 1910.94(c)(5), 1910.94(0X6),
191O.94(c)(7), and 1910.107(d)(2), and the following substances
listed in 1910.1000: lead, ehormate. VM a P naphtha, toluene.
mineral spirits, xylene, D-100 (Trjjnethyl benzene), D-15Q (Tetra-
methyl benzene), and cellosoive acetate and 1910.1025. The ap-
plication requests approval for a recirculatlng air system for a
paint booth at its facility. An Interim Variance was issued on
September 23, 1982.
The only worksite covered by the application is located at
the John Deere Des Uoines Works, Ankeny, Iowa.
The applicant has certified that employees who would be af-
fected by the variance have been notified of the application by
posting and by delivering a copy to the employees' representative.
Notice has also been given to the employees informing them of their
right to petition the Commissioner of Labor for a hearing. Iowa
Bureau of Labor staff have discussed the application and relevant
procedures with the employees' representatives.
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02/28/94 12:52 tJfl!9 541 2157 EPA/AEERL/RTP.NC @003/004
II. APPLICATION
The application provides for the recirculatiog of air for
the paint booth instead of the existing once-through system.
The applicant states that it will provide protection to employees
which is equal to or greater than that required by the standards.
Employees will be required to wear positive pressure air hoods
provided with purified compressed air which is free from oil,
water or odor and shall meet at least the requirements of the
specifications for Grade D breathing air as described in Compres-
sed Gas Association Commodity Specifications G-7.1-1966. Exhaust
air will be filtered through water to remove particulates.
Measures will be taken to prevent drift from the paint booth to
other work spaces. Procedures and equipment will assure that
solvent concentrations in the booth do not exceed twenty-five (25)
percent of the L.E.L. (lower explosive limit), flashback protec-
tion approved by Factory Mutual is provided.
The applicant states that the operation and procedures con-
templated in the application will permit the utilization of an
innovative technique of the sort contemplated by Iowa Code section
88.1. It is further stated that the concept offers a unique op-
portunity to reduce emissions from the spray booth thereby im-
proving the quality of the air in the environment.
Testing at the facility has indicated that the methods pro-
i
posed by the applicant does not further expose employees to over-
exposures of toxic substances. While the employer requires em-
ployees to wear respirators, such practice is only permitted
until technological advancements will allow for the installation
of engineering controls to permit employees to work in the spray
booth without respirators.
III. PROCEDURES
Any interested person may view a copy of this application
and supporting materials in the office of the Iowa Bureau of
Labor, 307 East 7th, Des Mainea, Iowa. Walter H. Johnson, Deputy
Commissioner, is the contact person.
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02/28/94 12:53 C919 541 2157 EPA/AEERL/RTP.NC
il 004/004
IV. ORDER
It appears from the application for a permanent variance
and testing and observations of toe equipment and procedures.
that the procedures, practices, methods, and operations proposed
to be instituted by the applicant will provide safeguards against
injury or illness to employees as contemplated by the standards.
THEREFORE, IT IS ORDERED pursuant to the authority of Iowa
Code section 88.5(3) and 530-5.8(88)IAC. that the applicant, John
Deere Des Uoines Works of Deere & Company, Is granted a Permanent
Variance.
The applicant shall- comply with all other provisions of the
Iowa Occupational Safety and Health Standards.
The applicant shall give notice to all affected employees of
the terms of this Permanent Variance Order by the same means re-
quired to inform them of this application.
The Permanent Variance Order shall be effective as of the
17th day of August, 1984,
Allen J.
Commissioner of Labor
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APPENDIX C
EXCERPTS FROM AN OSHA INSPECTION REPORT
108
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Occupational Safety and Health Administration
Citation and Notification of Penalty
U.S. Department of Labor - OSHA
Progress Plaza
49 North Progress Avenue
Harrisburg, PA 17109
3. Issuance Date
08/PB/91
4. Inspection Number
10P59709A
5. Reporting ID
0316700
7. Optional Report No.
S70
6. CSHO ID
UP359
8. Page No.
8 of 22
1. Type ol Violalion(s)
Serious
Citation Number
01
10. Inspection Date(s):
4/15/91 - 4/25/91
The violation(s) described in this
Citation are alleged to have oc-
curred on or about the day the
inspection was made unless
otherwise indicated within the
description given below.
11. Inspection Site:
Bair Station Road
York, PA 17405
BUY Combat Systems Track Vehicles
and its successors
P.O. Box 1512
York, PA 17405
THE LAW REQUIRES that a copy of this Citation be posted immediately in a prominent place at or near the location of violation(s) cited below. The
Citation must remain posted until the violations cited below have been abated, or tor 3 working days (excluding weekends and Federal holidays), whichever
Is longer.
This Citation describes violations of the Occupational Safety and Health Act of 1970. The penatty(ies) listed below are based on these violations. You must
abate the violations referred to in this Citation by the dates listed below and pay the penalties proposed, unless within 15 working days (excluding weekends
and Federal holidays) from your receipt of this Citation and penalty you mail a notice of contest to the U.S. Department of Labor Area Office at the address
Shown above. (See the enclosed booklet which outlines your rights and responsibilities and should be read in conjunction with this form.) You are further
notified that unless you Inform the Area Director in writing that you intend to contest the Citation or proposed penalties within 15 working days after receipt,
this Citation and the proposed penalties will become a final order of the Occupational Safety and Health Review Commission and may not be reviewed by any
court or agency. Issuance of this Citation does not constitute a finding that a violation of the Act has occurred unless there is a failure to contest as provided
for in the Act or, if contested, unless the Citation is affirmed by the Review Commission.
7c
29 CFR 1910.24
-------
U.S. Department of Labor
Occupational Safety and Health Administration
Citation and Notification of Penalty
U.S. Department of Labor - OSHA
• Progress Plaza
49 North Progress Avenue
Harrisburgt PA 17109
1. Type of Violation(s) 2. Citation Number
Other
02
The violation(s) described in this
Citation are alleged to have oc-
curred on or about the day the
inspection was made unless
otherwise indicated within the
description given below.
11. Inspection Site:
Bair Station Road
York, PA 17405
3. Issuance Data
08/SB/91
4. Inspection Number
10259703 b
5. Reporting ID
0316700
7. Optional Report No. .
270
6. CSHO ID
W2359
8. Page No.
6 of 10
10. Inspection Date(s):
4/15/91 - 4/25/91
fl.Tb:
BUY Combat Systems Track Vehicles
and its successors
P.O. Box 1512
York, PA 17405
THE LAW REQUIRES that a copy of tnis Citation be posted immediately in a prominent place at or near the location of violation(s) cited below. The
Citation must remain posted until the violations cited below have been abated, or for 3 working days (excluding weekends and Federal holidays), whichever
Is longer.
This Citation describes violations of the Occupational Safety and Health Ad of 1970 The penalties) listed below are based on these violations. Vou must
abate the violations referred to in this Citation by the dates listed below and pay the penalties proposed, unless within 15 working days (excluding weekends
and Federal holidays) from your receipt of this Citation and penalty you mail a notice of contest to the U.S. Department of Labor Area Office at the address
shown above. (See the enclosed booklet which outlines your rights and responsibilities and should be read in conjunction with this form.) You are further
notified that unless you inform the Area Director in writing that you intend to contest the Citation or proposed penalties within 15 working days after receipt,
this Citation and the proposed penalties will become a final order of the Occupational Safety and Health Review Commission and may not be reviewed by any
court or agency. Issuance of this Citation does not constitute a finding that a violation of the Act has occurred unless there is a failure to contest as provided
tor in the Act or, if contested, unless the Citation is affirmed by the Review Commission.
8
29 CFR 1910.29(a)(4)(ii): Scaffold caster(s) were not provided with
a positive wheel and/or swivel lock to prevent movement:
(a) Building 417 - One (1) wheel lock was missing from
manually propelled mobile scaffold, on or about
April 16, 1991.
29 CFR 1910.107(c)(6): Electrical wiring and equipment outside of
but within SO feet of spraying area(s), and not separated there from
by partitions, did not conform to the provisions for Class 1, Division
2, hazardous locations:
(a) Building §4, Spraying Area, Outside Door - Electric
wiring was not of the explosion proof type, on or
about April 15, 1991.
09/05/91
09/18/91
Penalties
Are Due
Wlttiln 15
Days of
Receipt
rtTrifs
NOtifiCSuOr
Unless
Contested
(See
enclosed
Booklet)
ThlsSeetit
May Be
Detached
Before
PdStlftQ
12. Hem Number
13. Standard. Regulation or
Section of the Act Violated
14. Description
15. Date by Which
Violation Must
Be Abated
16. Penalty
1
0.0(
0.0(
17. Area Di
H. Fink
Ifast Pg
NOTICE TO EMPLOYEES — The law gives an employee or
his representative the opportunity to object to any abate-
ment date set for a violation if he believes the date to be
unreasonable. The contest must be mailed to the U.S.
Department of Labor Area Office at the adrjre5*> shown
above within 15 working days (excluding weekends and
Federal holidays) of the receipt by the employer of this Cita-
tion and penalty.
EMPLOYER DISCRIMINATION UNLAWFUL - The law pro-
hibits discrimination by an employer against an employee for
filing a complaint or for exercising any rights under this Act.
An employee who believes that he has been discriminated
against may file a complaint no later than 30 days after the
discrimination with the U.S. Department of Labor Area Of-
fice at the address shown above.
EMPLOYER RIGHTS AND RESPONSIBILITIES — The enclosed booklet outlines employer rights and responsibilities and
should be read in conjunction with this notification. ORIGINAL
fetal
Pinilty
torThli
Citation
Mite Cfwckw
Monty OxMr
PMblt to:
"OOt-OSHA"
Indict*
buptetlon
Numb*'
on
110
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