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OAR Box 1413 

Prepped by Ollie Stewart 

Document Number: 

31)11-1-31 

Docket Number: 

A-94-52 

Printed 7/9/2008 3:11:21 PM Sheet 31 of 114 
IN/ID 

1TAP 

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MINNESOTA 

TECHNICAL. 

ASSISTANCE 

PROGRAM 

Reducing Styrene Emissions in 

Fiber Reinforced Plastic Operations 

PROJECT SUMMARY 

Project 

Product/industry 

Waste stream/chemical 

Results 

Examine styrene emissions levels of four different 

fiberglass resins, from conventional to low-styrene resins. 

Examined bamers to incorporating low-styrene resins into 

existing operations. Project conducted at Sunrise 

Fiberglass; Wyoming, Minnesota. 

Fiber reinforced plastics 

Styrene emissions 

Styrene emissions from low-styrene resins were reduced 

by 25 to 45 percent compared against the conventional 

resin used at Sunrise Fiberglass. Using low-styrene 

resins could save $1,800-4,440 per year by reducing the 

need for increased ventilation to meet the upcoming 

OSHA workplace exposure standard for styrene. 

Two of the low-styrene resins examined could be 

substituted directly into production operations at Sunrise 

Fiberglass without equipment or process changes. A third 

resin would require modifications to existing spray 

equipment at a cost of approximately $1,200. 

Project Background 

A number of recent initiatives by regulators have pressured the fiber-reinforced plastics (FRP) 

industry to reduce styrene emissions in both the workplace and the environment. Emissions 

can be reduced either by purchasing and installing better pollution control equipment, or by 

process changes that prevent or reduce pollution in the first place. The major objective of tiie 

project was to demonstrate styrene emission reductions by using low styrene emission (LSE) 

resins in an open-mold FRP operation. 

The project evaluated one type of process change—the substitution of low styrene resins in 

place of standard resins—as a method of reducing styrene emissions. Low styrene resins were 

developed to meet the strict air emissions standards in California but are not widely used in 

Minnesota. This is because past emission limits on the FRP industry in this region have been 

almost nonexistent. The project also tests some of the industry's preconceptions about lowstyrene resins that have formed a barrier against their use. 

1313 5t h Stree t SE Suite E0 7 

Minneapolis, Minneeota 5B414-4B0 4 

C61S) 687-464 8 

CBOO) 647-001 5 CMinnesota only) 

FAX t612> 687.476 9 

The Minnesota Office of Waste Management's M n TAP program ie supported with a grant t o the School 

of Public Health, Division of Environmental and Occupational Health, a t the University of Minneeota . 
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Factors examined in this study that would affect the change to a LSE resin substitute include: 

cost of LSE resins, requirements for specialized process equipment, workability of the material 

by the FRP operator, and resulting physical properties of the laminate. A local resin supplier, 

Worum Fiberglass Supply Company of St. Paul, Minnesota, assisted with the selection of 

materials. Their assistance helped ensure that the resins tested would: 1) consider the above 

factors, 2) be locally available, and 3) be applicable to the majority of open-mold FRP 

companies in Minnesota. 

This project was conducted at the facilities of Sunrise Fiberglass in Wyoming, Minnesota with 

the assistance of the staff at Sunrise. Sunrise uses the open-mold procedure to manufacture 

products ranging firom water-directive flumes, to large cabs used for heavy equipment. Its 

operations are typical of many Minnesota FRP open-mold facilities. Data firom the 1989 Toxic 

Release Inventory (TRI) showed that open-mold operations constitute the largest use of styrene 

resin in Minnesota in terms of number of facilities using the operation, volume of resin 

consumed, and volume of styrene released to the environment. 

Regulatory Incentives for Change 

Incentives to reduce styrene emissions are being driven by increased government regulations. 

In 1989, the Occupational Safety and Health Administration (OSHA) established rules to 

reduce styrene vapor exposure limits by 50 percent by the year 1993. The regulations will 

become effective on December 31,1993, and will require FRP operations^o meet*a>50 parts 

per million (ppm) personal exposure limit (PEL) and a 100 ppm short-termexpo.sure limits.^ 

(STEL). This reduction can be achieved by instituting changes in work practices such as: 

using different resins; practicing better housekeeping; using a closedrinold process; or by *> 

mechanical controls such as increasing the ventilating capacity of the* facility. UnliMhe / 

regulations become effective, an approved respirator program must be uqed to meet the / / 

requirements of the ruling. °0^

 >*s

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Other regulations will come firom the 1990 Clean Air Act Amendments (CAAA) air quality 

standards that will reduce the allowable styrene emissions from a FRP operation. Under Title 

m of the CAAA, styrene is listed as a hazardous air pollutant (HAP) for which boat 

manufacturing and reinforced plastic composite producers have been listed as source 

categories. Maximum Achievable Control Technology (MACT) standards will be written to 

reduce HAP emissions for the source categories. The dates for establishment of these 

standards are November 15, 1997, for the reinforced plastic composite producers and 

November 15, 2000, for the boat manufacturers. The standards may closely resemble those 

already established in California by the South Coast Air Quality Management District's 

(SCAQMD) Rule 1162, which are the toughest standards in the United States. Rule 1162 

requires that styrene emission reductions be made by using one of the following methods: 

• Use polyester resin that contains less than 35 percent styrene. 

• Use polyester resin that emits less than 60 gm/m* during curing. 

• Use the closed-mold process. 

• Use an emission-control device that captures 90 percent of the styrene vapors. 

SCAQMD's Rule 1162 also requires the use of airless, air-assisted spray equipment in spray 

lay-up applications. 

In Minnesota, the Minnesota Pollution Control Agency (MPCA) will require FRP facilities 

that have a potential to emit more than 25 tons per year of styrene to apply for air quality 

permits. This means that any FRP operation with one piece of spray equipment will exceed 

this limit and will require a permit. 

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Resins examined 

The study examined the following nonfillable-type resins: 

1. A conventional general purpose (GP) ortho resin with a styrene content of 46.0 percent 

that is catalyzed with methyl ethyl ketone peroxide (MEKP). This is the primary resin 

currently used at Sunrise Fiberglass. 

2. A general purpose ortho resin containing 43.9 percent styrene, catalyzed with benzoyl 

peroxide (BPO). 

3. A LSE general purpose resin containing 38.0 percent styrene, catalyzed with MEKP. 

4. A LSE general purpose resin containing 33.1 percent styrene, catalyzed with MEKP 

which meets the requirements of SCAQMD's Rule 1162. 

Resins selected for the study present two different approaches taken by raw material 

manufacturers to reduce styrene emissions. In the first approach, the polyester component of 

the MEKP-catalyzed LSE resin was re-engineered to produce a material with properties that 

are comparable to the properties of conventional resins, but contain substantially less styrene 

monomer. This was accomplished by incorporating some dicyclopentadiene (DCPD) character 

into the polyester chain. A typical ortho polyester is produced by reacting orthophthalic acid 

with ethylene or propylene glycol, which is then diluted with a styrene monomer until a 

workable viscosity is achieved. Polyesters that are produced with DCPD as the major acid 

component are used to produce resins called low-profile DCPD resins and are easily 

formulated to yield low styrene levels. These resins give superior finish and are used in 

applications where a high visual quality is desired. Drawbacks to the use of these materials as 

general purpose resins is that they tend to be lower in strength and more brittle. For these 

reasons, a blend of orthophthalic and DCPD acids is used to produce the polyester component 

used in general purpose LSE resins. 

The second approach taken by manufacturers is to use a BPO-catalyzed resin system to reduce 

styrene emissions. The resins used in these systems differ slightly from the conventional 

MEKP-catalyzed resins in that the BPO systems are promoted with amines, whereas MEKP 

systems are promoted with cobalt salts. The BPO-catalyzed resin is expected to give lower. 

styrene emissions than a MEKP-catalyzed resin due to a faster reaction rate and a lower 

temperature at peak exotherm. 

Experimental Approach 

The experimental considerations of the study were to: 1) use the open-cup static emissions test 

(from SCAQMD's Rule 1162) as a prescribed method for comparing the styrene emissions from 

test samples; and 2) quantify the styrene emissions firom the spray lay-up and cure steps of the 

open-mold process for each of the test samples using standard fabricating techniques and 

equipment at Sunrise Fiberglass. 

Open-cup static emissions test. This test determines the overall flux of styrene from, a 

catalyzed resin sample under controlled conditions, and is a quick and easy way to compare 

the performance of two resins. To perform this test, 100 grams of catalyzed resin is weighed 

into a one-gallon size paint can lid, allowed to polymerize, cooled to room temperature, and 

then reweighed. The difference between the initial and final weight is used to calculate the 

static emissions. This simplified test simulates styrene losses firom the curing step of an FRP 

process. 

Determining emission factors. Styrene emissions from the open-mold FRP operation at 

Sunrise Fiberglass result from the spray lay-up and the cure steps of the FRP process. 

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Therefore, the overall emission factor would be comprised of contributions firom these two 

steps. Trials were run to quantify the emissions firom these two steps in a way that simulated 

the actual production environment (technique and equipment) at Sunrise Fiberglass. An 

important assumption in these trials is that the major volatile component is styrene, and that 

emissions from the catalyst (or other volatile components) are negligible compared to styrene. 

Quantifying Emissions from Simulated Production Trials 

Preliminary trials with the conventional ortho resin currently used at Sunrise Fiberglass 

showed that volatile emissions and the temperature at peak exotherm are dependent on 

catalyst concentration. As the catalyst concentration is increased, the heat generated firom 

the polymerization increased, leading to a higher temperature at peak exotherm. This 

increased temperature tends to increase volatile emissions because styrene has a fairly low 

boiling point. 

To minimize the variability in emissions due to catalyst concentration, a series of geltime 

tests were performed at Sunrise Fiberglass for each of the resin systems to determine the 

catalyst concentration required to achieve a geltime of 20±2 minutes. The range ofthe 

catalyst concentration for the MEKP-catalyzed systems was 1.5+0.3 percent based on the 

weight of the resin. The BPO-catalyzed system was catalyzed at 2.0 percent, which is typical 

for that type of system. 

Cure step emissions. The styrene emissions resulting from the cure step of the FRP process 

were quantified by a method equivalent to the open-cup test. For each of the test resins, onefoot-by-two-foot laminate samples were produced using a glass content of 4.5 ounces per square 

foot. The resulting sample was weighed, set aside to cure, and then reweighed. The 

difference between the initial and final weight was used to calculate the static emissions and 

the emission factor for the cure step. 

Spray lay-up emissions. A das-Craft LPA Series spray-up system was used to determine 

the styrene emissions resulting from the spray step. In this test, known quantities of resin 

and catalyst were dispensed through the spray equipment and collected in a container. The 

difference in weight between what was sprayed and what was collected was used to calculate 

the spray-related emissions. 

Material handling and processing. The FRP operating technician, who made the trial 

samples at Sunrise Fiberglass, evaluated how easy or difficult it was to work with each 

material tested, and how well each material was processed through the spray equipment. 

This evaluation was important in deterrnining any potential problems or barriers that a 

material substitution would present for Sunrise fiberglass. 

Results 

The data in Table 1 show that the reduction in static emissions firom the LSE resins is 24 to 

30 percent less than static emissions from the conventional resins. For the MEKP catalyzed 

resin'samples, the static emissions decreased in approximate proportion to the styrene content 

of the resins. The temperature at peak exotherm also decreased as the styrene content of the 

resin decreased. This factor results in lower emissions because the bulk temperature bf the 

resin does not achieve as high a temperature as the conventional resin during the cure, 

causing less styrene monomer to volatilize. 

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Table 1: Open-cup static emissions firom polyester resins. Ambient conditions: temperature= 

69±2°F; relative humidity <40%. 

7 Resin '" 

\ Description 

1 Conventional 

Ortho-GP 

Ortho-GP, BPO 

Catalyzed 

LSE Resin 

LSE Resin 

Rule 1162 

Styrene Content 

46.0 

43.9 

38.0 

33.1 

Temperature at ,|iPeak Exotherm (°F) 

240 

235 

225 

210 

Static>Enus^ons; 

*

v

'c-\gmfe^^< 

69.6 

50.9 

52.8 

48.4 

The styrene content of the BPO-catalyzed resin system was roughly equal to the conventional 

ortho resin; however, the static emissions firom the BPO-catalyzed system was very low. This 

is because the BPO-catalyzed system produces a higher molecular weight polymer at a faster 

rate in the reaction and quickly produces a tight matrix that hinders the escape of free 

styrene monomer. 

Table 2 summarizes the results of the styrene emissions from the cure and spray lay-up steps 

used in the FRP process trials. The spray lay-up step was found to be responsible for over 70 

percent of the overall styrene emissions. The results for static emissions listed in Table 2 are 

considerably higher than the results listed in Table 1 and are most likely related to plant 

conditions, especially air movement. 

Table 2: Emissions from cure and spray lay-up steps from the simulated production trials. 

Ambient conditions: temperature = 68±1°F; relative humidity <40%. 

Resin 

Description 

Styrene^ £ 

Content ^ », 

Static Emissions;^ 

i igmhhi*) \rj: ^ •<;<,>jcure'•v' . ^A -f y y*. syjwtw w*i yiv.y< 

Conventional 

Ortho-GP 46.0 99.5 0.047 0.017 0.064 

0rtho-GP3P0 

Catalyzed 43.9 65.3 0.024 0.011 0.035 

LSE Resin 38.0 79.6 0.035 0.013 0.048 

LSE Resin 

Rule 1162 33.1 57.5 0.031 0.010 0.041 

For the MEKP-catalyzed resin samples, the percent reduction in the overall emission factor of 

a LSE resin, when compared to the conventional resin, was found to be approximately 8 

percent higher than expected by the percent reduction of styrene content of the same 

materials. This may be related to the higher viscosity of the MEKP catalyzed LSE resins. 

Each of the MEKP catalyzed resins was processed through the same piece of equipment under 

the same operating conditions Gn other words, the energy input to the liquid phase for 

atomization was the same for all of the resins). The increase in viscosity leads to larger 

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droplet size, which reduces the overall number of droplets and exposed surface area of the 

spray, thereby decreasing the release of styrene. 

Table 2 also shows that the BPO-catalyzed resin dramatically out-performed the ability of the 

MEKP-catalyzed resins to reduce emissions. Emissions reduction with the BPO-catalyzed 

resin during the cure-step is related to a faster post-gel reaction rate, but the cause of 

emissions reduction from the spray step is less understood. One reason for greater reduction 

may be that when the catalyst and resin streams are impinging on each other to facilitate 

mixing during spray-up, the water in the catalyst (38 percent by weight) does not readily mix 

with the resin and instead migrates to the droplet surface, where it forms a barrier that 

inhibits styrene release. 

Processing Characteristics of Resins 

The viscosity of the MEKP-catalyzed LSE resins tended to be 200-300 centipoise higher than 

conventional resins. This caused concern that the mixing of the resin and catalyst streams 

during spray-up and the wetting of the glass reinforcing material with the resin would be 

problematic. The LSE resins were processed through air-assisted airless spray equipment 

using typical fabricating techniques. 

Mixing considerations. Mixing of the catalyst and resin streams during spray-up was found 

to be adequate for all the materials in the study. There was no evidence of soft or tacky spots, 

or areas of obvious discoloration within the cured laminate sample. 

Glass wet-out characteristics. All the LSE resin samples exhibited glass wetout 

characteristics comparable to the conventional resin. A common misconception by industry is 

that the higher viscosity of the LSE resins will increase the amount of manual labor required 

to roll out trapped air bubbles and to distribute the resin. In all cases, the time required by 

the operator to prepare the laminate samples was similar, and each of the cured samples 

exhibited the translucency characteristic of completely saturated glass fibers. 

Wet weight of laminate samples. The wet weight of the laminate samples produced firom 

LSE resins tended be higher than the sample produced from the conventional resin. The 

increase tended to parallel the viscosity increase of the LSE resin. At the upper extreme, 

laminate samples produced from the "Rule 1162" LSE resin (has a viscosity 300 centipoise 

higher than conventional resin) resulted in samples with a wet weight that was 8 percent 

higher than the conventional resin samples. The weight of the glass in each sample was the 

same; therefore, the weight increase of the laminate samples was due to an increase in the 

amount of resin used. 

This situation is thought to be related more to operator technique and lack of experience with 

LSE resins, than to a need to use more LSE resin in the process. An operator with, extensive 

experience with a particular resin gets a feel for the amount of liquid required to saturate a 

piece ;of glass reinforcing material. Since conventional GP resins are less viscous than LSE 

resin&sand have a slightly greater tendency to flow, an operator inexperienced with LSE resins 

may spray too long as a result of a slight difference in wet-out rates. 

Economic Considerations 

Substituting a LSE resin into the existing FRP operation at Sunrise Fiberglass is contingent 

upon the following economic factors: 

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• Raw material costs. 

• Capital costs for equipment to process the raw materials. 

• Costs to achieve compliance with future regulations (i.e., modified or new ventilation 

systems), especially the OSHA 50 ppm PEL for styrene. 

Table 3 summarizes the costs associated with these factors for Sunrise Fiberglass. 

Table 3: Economic analysis of LSE substitutes.* 

Variables 

Conventional 

, Ortho-Resin 

(46% styrene) ^ E ,\'<38*# styreneX:l 

ISEResxnV^-

, X33.i% stg£ene);<v 

Catalyst level (%) 1.5 1.6 1.7 2.0 

Catalyst cost"' ($/yr) 2,850 3,040 3,230 4,800 

Resin cost' ($/yr) 70,000 70,000 70,000 70,000 

Annual catalyst + 

resin cost ($/yr) 72,850 73,040 73,230 74,800 

Added cost of 

raw material 

substitution ($/yr) 

190 380 1,950 

Vent costs to meet 

50 ppm PEL* ($/yr) 9,000 7,000 5,940 2,700 

Reduction in vent 

cost to meet 50 

ppm PEL ($/yr) 

2,000 3,600 6,300 

Annual savings 

as a result of LSE 

substitution ($/yr) 

1.810 4_5g 

"Analysis is based on the following information related to Sunrise Fiberglass: annual resin 

consumption is 100,000 pounds; present ventilation air requirement to meet 100 ppm PEL is 10,000 

cfm; and production fadiity specifications are 60 ft by 104 ft by 10.7 ft (67,000 /r*J 

b

 Catalyst cost is $1.90/lb. for MEKP; and $2.40/lb. fbr BPO. 

• All resin costs are $0.70/lb. 

•••"TW 

* Assumes that ventilation air requirements are doubled to meet 50 ppm PEL. Operating costs 

associated with heating the makeup air and operating the system were taken from a 1988 SIRC 

report, "Cost of Compliance and Economic Impact upon Selected Reinforced Plastics and Composites 

Industries of a Proposed OSHA Standard of 50 ppm fbr Styrene." 

Raw material costs. The added expense resulting from substituting the LSE alternatives 

into the present production situation (shown in Table 3) is related to the catalyst requirements 

only. The cost of the BPO catalyst is 25 percent higher than that of the MEKP catalyst and is 

processed at a higher concentration. The added material expense associated with the MEKP-

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catalyzed LSE systems resulted firom the need to increase the catalyst level to achieve the 

desired geltimes used in the study. ' 

Capital costs related to process equipment. Currently, Sunrise Fiberglass uses the dasCraft LPA series spray equipment for spray lay-up. To process the MEKP-catalyzed LSE 

resins, no changes to existing equipment would be required and the material could be directly 

substituted. However, equipment changes would be required to process the BPO-catalyzed 

LSE resin because the BPO catalyst is supplied as an aqueous suspension with a viscosity that 

is higher than MEKP catalysts. The present equipment at Sunrise Fiberglass could be 

upgraded to accommodate the BPO catalyst by installing a mixer that would keep the catalyst 

suspended during production, and by installing larger piping for delivering the catalyst to tiie 

spray gun. For the Glas-Craft LPA series spray unit, the conversion cost would be 

approximately $1,200. The cost of a new spray system for either catalyst would be 

approximately $7,000. 

Compliance-related costs. The economic impact of the OSHA rule that requires reducing 

the PEL of styrene from 100 ppm to 50 ppm by December 31,1993, is an issue of concern to 

Sunrise Fiberglass and many other FRP operations. The present status of the rule requires 

that the 50 ppm exposure limit be met by mechanical means or work practice changes that 

eliminate the need for respirators by the workers. 

The mechanical options available to achieve the OSHA requirements are: 

1. Increase the make-up air throughput of the existing ventilation system, provided the 

system has some flexibility to handle the increase (will result in increased operating 

costs). 

2. Upgrade the existing ventilation system with a make-up air unit and exhaust fans to 

increase capacity (will require a large capital expense). 

The existing ventilation system at Sunrise Fiberglass was designed to handle increased airflow capacity and could be increased sufficiently to meet the new OSHA requirements (as 

listed in option 1 above). The modifications would involve exchanging the existing fan pulleys 

with larger diameter pulleys to increase fan speed The makeup air heater unit has the 

flexibility to heat this larger volume of air. Added operating costs would be related to the 

higher power requirements to operate the fans and the higher heat requirements to heat the 

makeup air. Table 3 shows the approximate savings on ventilation costs for each ofthe LSE 

substitutes. 

If option 1 (listed above) was not available to Sunrise Fiberglass and a switch to a LSE resin 

could not ensure compliance, the capital expense required to design and upgrade the existing 

ventilation system would be substantial. For Sunrise, the capital expense to upgrade the 

makeup air unit and the exhaust fans would exceed $35,000, according to a report by the 

Styrene Infonnation and Research Council (SIRC). When the raw material costs are taken 

into account, the annual savings for Sunrise could range from $2,000 for the LSE resin 

containing 33 percent styrene, to $4,400 for the BPO-catalyzed LSE resin. For the BPOcatalyzed LSE resin, the payback period would be less than four months if the cost to upgrade 

the spray equipment to handle the BPO catalyst is included in the economic analysis. 

Conclusions 

The results of the study show that styrene emissions from the open-mold FRP process at 

Sunrise Fiberglass could be reduced substantially by using LSE resins (BPO- or MEKP-

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catalyzed). The MEKP-catalyzed LSE resin systems were found to have the following 

characteristics: 

• Reduce styrene emissions by 25-36 percent. 

• Easily incorporated into the existing process. 

• Required no spray equipment changes. 

• Have the lowest added raw material costs. 

Although the viscosity of these materials is somewhat higher (200-300 centipoise) than the 

conventional resins, the processing characteristics of the materials, with respect to wetout, 

was comparable to conventional materials. There was a tendency to overapply the ISE 

materials during spray-up but this was speculated to be related to the operators lack of 

experience with these more viscous materials and could be overcome with time. 

The BPO-catalyzed LSE resin system was found to have the following characteristics: 

• Reduced styrene emissions by 46 percent. 

• Easily incorporated into the existing process. 

• Required a $1,200 expense to upgrade existing spray equipment to handle BPO catalyst. 

• Increased raw material expense because of BPO catalyst. 

• Offered greatest savings in ventilation costs required for compliance with OSHA 50 ppm 

PEL for styrene. 

• Comparable processing characteristics to the conventional resin. 

A present-worth analysis comparing the LSE resins showed that the conversion to a BPOcatalyzed resin would yield the most economic benefits. Assuming a five-year life for the 

equipment and an interest rate of 7 percent, the present worth of savings and costs are $7,400, 

$11,000 and $16,700 for the MEKP-catalyzed LSE resins and the BPO-catalyzed resin, 

respectively. 

Options for Achieving Compliance. Minnesota FRP shops can achieve the future OSHA 

compliance requirements by implementing one of the two following options, depending on 

their current styrene emission levels: 1) install mechanical changes to increase ventilation 

capacity, and 2) substitute a LSE resin into the current process. 

Before either of these options are implemented, however, current emissions levels must be 

determined. OSHA requires that styrene exposure levels be determined by worker exposure 

monitoring. One method of exposure monitoring requires that a worker wear a compact^ 

^ styrene-sensitive monitor on his or her shirt collar for the duration of a work period The 

I exposure monitor is then sent for analysis to determine styrene exposure levels. [Note: It is 

'" likely that most FRP shops have already done some exposure monitoring, and know what 

their baseline worker exposure levels are for the resin system they are using.] 

If the results of worker exposure monitoring indicate that the 8-hour time-weighted average 

CTWA) for Hyrene is above the OSHA 50 ppm PEL but below 70 ppm, it may be possible to 

reduce the TWA to the required compliance level by substituting a LSE resin into the present 

process. Two methods exist for determining whether a LSE resin can reduce styrene 

emissions to required compliance levels: 1) substitute a LSE resin into the present process for 

a testing period of a day or more and perform worker exposure monitoring to detennine 

exposure levels; or 2) use the open-cup test to screen LSE resins for their potential to reduce 

exposure. 

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The use of the open-cup test assumes that styrene concentration in the workplace is 

proportional to static emissions of the resin. To use the open-cup test method to compare one 

or more LSE resins to a current resin, determine the following: 

1. An 8-hour TWA for the present plant conditions. 

2. Open-cup static emissions for the resin presently in use. 

3. Open-cup static emissions for the LSE resin substitute. 

The expected TWA for the LSE substitute can be found by multiplying the present TWA (#1 

above) by the ratio of the static emissions results (divide #3 by #2). Once this procedure 

identifies resins that reduce emissions sufficiently, the best resin can then be selected for a 

plant trial during which exposure can be measured for verification. 

NOTE: The OSHA 50 ppm PEL rule has been challenged and overturned in other areas of the 

United States, and the future status of the rule in Minnesota is somewhat uncertain. Because 

of this uncertainty, Sunrise Fiberglass (and other FRP operations) are hesitant to implement 

changes in their processes, including the use of LSE resins. The possibility that future 

regulations may not require the proposed styrene emission reductions, along with familiarity 

with conventional resins, adds to the resistance to change. However, if the OSHA rule 

becomes law, the LSE resins would be a viable option for meeting worker exposure limits. In 

addition, LSE resins will help FRP operations meet future CAAA regulations. 

For More Information 

If you have questions about this study and would like more information about reducing 

styrene emissions, contact Randy Cook at MnTAP at 612/6274646 or 800/247-0015. 

References 

• Cost of Compliance and Economic Impact upon Selected Reinforced Plastics and Composites 

Industries of a Proposed OSHA Standard of 50 ppm for Styrene. Report to the Styrene 

Industry Research Council (SIRC). August 3,1988. Arthur D. Little, Inc. Reference No. 

61936. 

• Rules and Regulations, Volumes 1 and 2. January 1992. South Coast Air Quality 

Management District. Diamond Bar, CA. 

• 1989 Toxic Release Inventory (TRI) Report. Minnesota Emergency Response Commission. 

This styrene emissions reduction demonstration project was made possible by a grant from the 

U.S. Environmental Protection Agency (EPA) Pollution Prevention Incentives to States (PPIS) 

Program. 

(3/93) 

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APPENDIX 1 

List of Acronyms 

BPO benzoyl peroxide 

CAAA Clean Air Act Amendments of 1990 

DCPD dicyclopentadiene 

EPA Environmental Protection Agency 

FRP fiber reinforced plastics 

GP general purpose 

HAP hazardous air pollutant 

LSE low styrene emission 

MACT maximum achievable control technology 

MEKP methyl ethyl ketone peroxide 

MPCA Minnesota Pollution Control Agency 

OSHA Occupational Safety and Health Administration 

PEL permissible exposure limit 

PPM parts per million 

SCAQMD South Coast Air Quality Management District 

SIRC Styrene Information and Research Council 

STEL short term exposure limit 

TRI Toxic Release Inventory 

TWA time weighted average 

VOC volatile organic compound 

11 

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P.13 

"7f ;•" tf, 

APPENDIX 2 

Glossary of Terms 

1. Airless, air-assisted. A spray technology that delivers low pressure air to the 

resin/gelcoat and catalyst immediately after the two materials have been mixed. The airassisted containment forms a barrier around the materials, which develops a shield that 

prevents polyester or catalyst particles from becoming airborne emissions. Airless implies 

that air is not used to atomize the polyester or catalyst streams prior to mixing 

2. Emission factor. A number that quantifies the emissions from a process based on the 

inputs into the process. Dimensions on emission factors are mass emissions per mass 

material input to process. 

3. Exotherm. Internally-developed heat that accompanies a chemical reaction. 

4. Geltime. The length of time that a catalyzed polyester remains workable before it starts to 

solidify. 

5. Make-up air. Replaces air that is exhausted from a plant to meet ventilation 

requirements. 

6. Static emissions. Refers to the VOC emissions per unit surface area of exposed curing 

material. Results of the open-cup test are reported as static emissions. 

7. Wet-out. A measurement rate that measures how long it takes a reinforcing material to be 

completely saturated with resin. Rate is usually determined visually and measured in 

elapsed time. 

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