Reducing Emissions in Fiberglass Reinforced
Plastics Manufacturing
Geddes H. Ramsey and Carlos M. Nunez
U.S. Environmental Protection Agency
National Risk Management Research Laboratory
Research Triangle Park, NC 27711
Emery Kong, Mark Bahner, Robert Wright,
Andrew Clayton, and Jesse Baskir
Research Triangle Institute
Research Triangle Park, NC 27709-2194
INTRODUCTION
The U.S. Environmental Protection Agency (EPA) conducts tests of facilities to facilitate its
environmental programs. The data from these tests have supported the Maximum Achievable Control
program and are being supplied for use in updating the AP-42 guide (U.S. EPA, 1988) for the states and
others to develop emission estimates.
EPA has proposed National Emission Standards for Hazardous Air Pollutants (NESHAPs) for
the fiber-reinforced plastics and composites (FRP/C) industry. These standards, being developed to
reduce the emission of styrene from FRP/C facilities, were proposed in August 2001.
Pollution prevention techniques may help FRP/C companies substantially reduce their styrene
emissions. However, information is needed about the percentage reduction in emissions that pollution
prevention approaches can achieve. To meet this need, EPA's Air Pollution Prevention and Control
Division and Research Triangle Institute (RTI) determined baseline emissions and evaluated reductions
in styrene emissions that can be achieved through a variety of pollution prevention approaches for the
FRP/C industry.
This paper summarizes our evaluation of pollution prevention techniques, so that technical
assistance providers can provide better information to FRP/C facilities about pollution prevention
options. It gives background about the industry, describes the goals of this research, summarizes the
testing program, and provides some key preliminary results and conclusions from the research.
BACKGROUND
The FRP/C industry (excluding boat building) includes over 750 facilities nationally in as many
as 33 Standard Industrial Classification (SIC) categories ranging from transportation to electronics and
consumer products. Products manufactured include bathtubs and shower stalls, spas, truck caps and
vehicle parts, tanks and pipes, appliances, ladders, and railings. According to a 1993 industry screening
survey, more than two-thirds of FRP/C facilities have fewer than 50 workers (LaFlam and Proctor, 1995).
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More than 75% of the resin used in composites manufacturing is polyester resin that contains
styrene as a cross linking agent (SPI, 1992). A portion of this styrene is emitted during and after
application of the resin. Annual FRP/C industry styrene emissions based on EPA's Toxic Release
Inventory are estimated to be 17,100 tons (U.S. EPA, 1995).
The FRP/C industry employs a variety of manufacturing processes. As shown in Table 1, the
main manufacturing process is open molding (gel coat and resin spraying). Estimates indicate that open
molding is responsible for approximately 75% of the styrene emissions from the FRP/C industry. The
open molding process usually consists of the spraying of a wet (uncured) gel coat or resin to a mold in an
open environment. Styrene is emitted both during and after the application process.
Table 1: Manufacturing Processes Employed by the FRP/C Industry
Manufacturing Process Estimated % of Facilities Employing
Process*
Open Molding (gel coat and resin spraying) 60
Compression Molding 17
Filament Winding 12
Pultmsion 8
Cultured Marble Casting 6
Continuous Lamination 5
* Column total exceeds 100% because many facilities employ more than one type of manufacturing process.
Data are from LaFlam and Proctor (1995).
Facilities have chosen to use high ventilation rates to maintain styrene levels below the 50 ppm
worker exposure limit established by the Occupational Safety and Health Administration (OSHA).
Control of such high-volume, low-concentration waste streams is expensive with conventional end-of-
pipe control technologies. This makes pollution prevention an attractive alternative for reducing styrene
emissions.
Pollution prevention approaches are also attractive because, unlike carrier solvents used for
conventional sol vent-borne paints, styrene is an important component of the FRP curing chemistry. Since
styrene is not a carrier solvent, it is not evaporated during the manufacturing process. The styrene is
bound in the polymerization of the resin and most of the styrene is utilized in this cross-linking reaction.
Preventing the emission of styrene also decreases the amount of styrene needed in manufacturing.
RESEARCH GOALS AND TESTING PROGRAM
This research was conducted to quantify styrene emission reductions achievable through various
pollution prevention techniques (see Table 2).
Emissions testing was conducted in an isolated spray booth at the Reichhold Chemicals' physical
testing laboratory, located in Research Triangle Park, North Carolina. Although the facility is not a
production facility, it is typical of spray booths at FRP/C facilities. Laboratory conditions (e.g.,
temperature, relative humidity) were carefully controlled, and background concentrations of volatile
organic compounds (VOCs) were minimal. Air velocity in the booth was controlled through the use of a
baffle located behind the application equipment operator.
The mold used and the choice of equipment operator were not changed during the testing. Tests
employed three identical, box-shaped, male molds, with dimensions 2 ft (0.6 m) high by 2.5 ft (0.76 m)
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long by 2 ft (0,6 m) wide. A 2 in. (5 cm) flange surrounded the bottom of the mold for ease of part
removal. The total mold area, including the flange, was 24.5 ft2(2,28 m2). An experienced spray
equipment operator applied gel coats and resins during the tests.
Emissions' from processes employing pollution prevention options were compared to a baseline
case to examine reductions achieved. Emissions were analyzed by EPA Method 25A using a total
hydrocarbon analyzer with a flame ionization detector (FID). Five factors were examined to determine
their impact on styrene emissions: linear air flow velocity in the booth, operator spraying technique, gel
coat formulation, resin formulation, and application equipment. Baseline case conditions and pollution
prevention options examined are summarized in Table 2.
Spray Technique
Table 2: Baseline Test Conditions and Pollution Prevention Options Evaluated
Factor Base Conditions Pollution Prevention Option
Experienced operator, normal Experienced operator, controlled
technique (i.e., without consciously spraying technique
controlling overspray)
Air Flow Velocity
Application Equipment
Gel Coal
Resin
100ft/min(0.5m/s)
Air-assisted airless spray (external
catalyst mixing)
Isophthalic acid-based gel coat'
(styrene content 38.7%) methyl ethyl
ketone peroxide catalyst; 18-24 mils
(0.00046-0.00061 m) coating
thickness
Dicyclopentadiene-based low-profile
resin (styrene content
38.3%)/ methyl ethyl ketone
peroxide; 70-100 mils (0.0018-
0.0025 m) coating thickness
40 ft/min (0.2 m/s)
1. High-volume, low-pressure (internal
catalyst mixing)1
2. High-volume, low-pressure (external
catalyst mixing)1
3. Flow coaler (internal catalyst
mixing)2
4. Pressure fed roller (internal catalyst
mixing)'
Isophthalic acid/neopentyl glycol-based
gel coat ("low VOC," styrene content
25.4%) / methyl ethyl ketone peroxide
catalyst
Dicyclopentadiene-based low-
styrene resin (styrene content
35.3%) / methyl ethyl ketone
peroxide catalyst
Orthophthalie-acid-based styrene
suppressed resin / methyl ethyl
ketone peroxide catalyst
Orthophthalic-acid-based styrene
suppressed resin plus 0.1% wax /
methyl ethyl ketone peroxide
catalyst
1 Application equipment used for gel coat tests only.
2 Application equipment used for resin test only.
•' Gel coats contained no methyl methacrylate to allow assumption that total emissions were styrene.
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Gel coats were provided by Cook Composites and Polymers. All resins and catalysts were
provided by Reichhold Chemicals. Application equipment and a trained operator were provided by
Magnum Industries. Fiberglass roving used as a reinforcement material was provided by PPG Industries.
The flow coater and pressure fed roller require more time for application just as using a roller
would require more time in painting as compared to spraying. The large molds used in these tests were
similar to molds used in many production facilities and did not involve intricate shapes. The flow coaters
could be used in most applications, but the application time is the determining factor.
RESULTS AND CONCLUSIONS
All tests were conducted in triplicate, at a minimum, to permit statistical analysis of the results
obtained. Results were expressed in total grams (g) of styrene emitted, grams of styrene emitted per
square meter (g/m2) of mold surface, and emissions as a percentage of available styrene. Emissions
reductions were evaluated in comparison with baseline test conditions as described in Table 2.
Pilot tests, conducted to evaluate the effects of linear air velocity and operator spraying
technique on emissions, indicated that:
I) Over the velocity range examined, linear air velocity had no effect on styrene emissions.
2) Controlled gel coat spraying technique reduced styrene emissions by 24% when compared to
normal spraying technique (emission factor reduced from 225 to 172 g/m2).
Gel coat testing indicated that:
1) Low-VOC gel coat formulation reduced styrene emissions by 28% compared to the regular gel
coat (emission factor reduced from 170 to 122 g/m2);
2) Low-VOC gel coat required higher air pressure and larger tip size to improve the spray pattern
for application;
3) No significant emission differences were found from application with high-volume, low-
pressure (HVLP) spray equipment versus air-assisted airless equipment; and
4) No significant emission differences were found from application with internal-catalyst-mix spray
guns versus external-catalyst-mix spray guns.
Evaluations of resin formulations indicated that:
1) The low-styrene resin reduced emissions by 11% (from 195 to 173 g/m2) as compared with a
conventional low-profile resin.
2) The styrene-suppressed resin emitted 35% less styrene than the conventional low-profile resin
(from 195 to 126 g/m2).
3) The styrene-suppressed resin with 0.1% wax emitted 40% less styrene than the conventional low-
profile resin (from 195 to 117 g/m2).
Evaluations of resin application equipment indicated that:
1) Flow coating equipment resulted in 31% lower emissions than controlled spraying (emission
factor reduced from 195 to 135 g/m2);
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2) Flow coating equipment resulted in 51 % lower emissions than normal spraying (emission factor
reduced from 278 to 135 g/m2).
3) Pressure-fed roller equipment resulted in 33% lower emissions than controlled resin sprayup
(emission factor reduced from 195 to 131 g/m2).
4) Pressure-fed roller equipment resulted in 53% lower emissions than normal resin sprayup
(emission factor reduced from 278 to 131 g/m2).
Based on the results of these tests, the following pollution prevention approaches are
recommended for FRP/C open mold operations:
• use operator training to improve technique and reduce overspray;
« use non-spray application equipment, where feasible;
« use styrene-suppressed or low-styrene materials, where feasible; and
* adjust catalyst ratios, where feasible, to reduce cure time,
These test results show that significant reductions in styrene emissions can be achieved at
minimal cost through selection of processes and application techniques that prevent pollution. Pressure-
fed roller equipment provided the best reductions in comparison to spray techniques.
REFERENCES
LaFlam, Greg, and Melanie Proctor (Pacific Environmental Services), 1995, Industry- Description
Memorandum. Memorandum to Madeleine Strum, U.S. Environmental Protection Agency, Office of Air
Quality Planning and Standards, Research Triangle Park, NC; October 17.
SPI Composites Institute, 1992. Introduction to Composites Handbook, Society of the Plastics Industry,
Inc., New York, NY.
U.S. EPA, 1987-1993 Toxics Release Inventory, Users Manual; EPA-749/C-95-004 (NTIS PB95-
503793); U.S. Environmental Protection Agency, Office of Pollution Prevention and Toxics,
Washington, DC; August 1995.
U.S. EPA, Compilation of Air Pollution Emission Factors. Volume I: Stationary Point and Area Sources,
Fourth Edition and Supplement B, AP-42 (NTIS PB89-128631). U.S. Environmental Protection Agency,
Office of Air Quality Planning and Standards, Research Triangle Park, NC; September 1988.
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4, TITLE AND SUBTITLE
Reducing Emissions in Fiberglass Reinforced
Plastics Manufacturing
NRMRL-RTP-P-287
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
. REPORT NO.
EPA/600/A-02/089
2.
3. REC
5. REPORT DATE
6. PERFORMING ORGANIZATION CODE
1. AUTHOR(S) , .
G. H. Ramsey and C. M. Nunez (EPA), and E. Kong,
M. Bahner, R. Wright, A. Clayton, and J. Baskir (RTI)
8, PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Research Triangle Institute
P. O. Box 12194
Research Triangle Park, North Carolina 27709
10, PROGRAM ELEMENT NO,
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Air Pollution Prevention and Control Division
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Published paper;
14. SPONSORING AGENCY CODE
EPA/60.0/13
is. SUPPLEMENTARY NOTES APpcD project officer is Geddes H. Ramsey, Mail Drop 61, 919 /
541-7963. Presented at U.S. EPA Region 4 Green Technological Conference,
Atlanta, GA, 11/17-19/97.
16. ABSTRACT,.
The paper summarizes results of an evaluation of pollution prvention tech-
niques, so that technical assistance providers can provide better information to
fiber-reinforced plastics and composites (FRP/C) facilities about pollution preven-
tion options. It gives background about the industry, describes goals of this re-
search, summarizes the testing program, and provides some key preliminary re-
sults and conclusions from the research. Pollution prevention techniques may help
FRP/C companies substantially reduce their styrene emissions. However, informa-
tion is needed about the percentage reduction in emissions that pollution prevention
approaches can achieve. To meet this need, EPA determined baseline emissions
and evaluated reductions in styrene emissions that can be achieved through a variety
of pollution prevention approaches for the FRP/ C industry.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lOENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
Pollution
Styrene
Plastics
Fiberglass Reinforced
Plastics (FR/P)
Emission
Composite Materials
Pollution Prevention
Stationary Sources
Fiberglass
13B
07C
111
11D
14G
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThisReport;
Unclassified
21. NO. OF PAGES
5
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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