P.1 

OAR Box 1392 

Prepped by Ollie Stewart 

Document Number: 

130) ll-A-5 

Docket Number: 

A-94-52 

Printed 7/7/2008 9:45:58 AM Sheet 130 of 136 
E12_ 

' / "' • A-94-52 

DRAFT REPORT: 

"PRELIMINARY EMISSIONS TESTING 

AT DOW CHEMICAL ON 

JANUARY 4-5,1995" 

Prepared by: 

Research Triangle Institute 

P.O. Box 12194 

Research Triangle Park, NC 27709 

In cooperation with: 

U. S. Environmental Protection Agency 

Air and Energy Engineering Research Laboratory 

Research Triangle Park, NC 27711 

f'''7'!»h-f.f.'M; 

"#/.. 

RTI Project No. 5171-016 

JANUARY 30, 1995 
P.3 

TABLE OF CONTENTS 

1.0 INTRODUCTION 1 

2.0 OBSERVATIONS 1 

2.1 TEST SET-UP 1 

2.2 DAY 1 - HAND LAY-UP TEST 2 

2.2.1 Calibration gases 2 

2.2.2 Total hydrocarbon analyzer traces 3 

2.2.3 Background concentrations and end-of run considerations 3 

2.2.4 Mass balance measurements 4 

2.2.5 Emission measurement results 4 

2.2.6 Comparison of emissions (calculated from THC 

analyzer measurements) with AP-42 emission factors 5 

2.3 DAY 2 - GEL COAT SPRAYING TEST 5 

2.3.1 Duct flowrate verification 5 

2.3.2 Sampling system leakage considerations 6 

2.3.3 Total hydrocarbon analyzer traces 6 

2.3.4 Background concentrations, and end-of-run considerations 6 

2.3.5 Mass balance measurements 6 

2.3.6 Emission measurement results 7 

2.3.7 Comparison of emissions (calculated from THC 

analyzer measurements) with AP-42 emission factors 7 

2.3.8 Gel coat overspray observations 8 

2.4 ALTERNATIVE METHODS OF EXPRESSING EMISSION FACTORS . 8 

3.0 CONCLUSIONS 9 

4.0 RECOMMENDATIONS 10 

m 

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LIST OF TABLES 

1. Parameters for hand layup test 11 

2. Hand lay-up emission test results 12 

3. Parameters for gel coat spraying test 13 

4. Gel coat spray emission test results 14 

5. Emission factors for hand lay-up and gel coat spray runs 15 

LIST OF FIGURES 

1. Sketch of male fabricating mold, with surrounding flange 16 

2. Comparison of Dow "CamiHe" computer versus hand-recorded 

total hydrocarbon analyzer readings 17 

3. Total hydrocarbon analyzer trace for hand lay-up (hand-recorded values) 18 

4. Cumulative mass emission versus time for hand lay-up run of 1/4/95 19 

5. Gel coating emissions for run on 1/5/95, as recorded by 

Dow "Camille" computer system 20 

6. Gel coating emissions for first 5 minutes of run on 1/5/95, as recorded by 

Dow "Camille" computer system 21 

7. Cumulative mass emission versus time for gel coat spraying run of 1/5/95 22 

APPENDK 

Comparison of recent test results to AP-42 emission factors A-l 

* w> 

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1.0 INTRODUCTION 

Mark Banner visited the Dow Chemical Company facility in Freeport, Texas on January 

4-5, 1995, to observe preliminary testing of emissions from open mold fabrication procedures. 

The purposes of Mr. Bahner's observations were to witness the test results and to observe and 

comment on the procedures used to obtain the test results. The testing consisted of one hand layup run and one gel coat spraying run. Three measurement techniques were used: 

1) a total hydrocarbon analyzer (corresponding to EPA Method 25A), 

2) intermittent sampling with a gas chromatograph, and 

3) a mass balance method. 

2.0 OBSERVATIONS 

2.1 TEST SET-UP 

Fabrication procedures (hand lay-up and gel coat spraying) were performed in a ventilated 

enclosure. The enclosure was approximately 14 feet long, 10 feet wide, and 9 feet high. The 

sides of the enclosure consisted of a wooden frame, over which plastic mylar sheets were stapled. 

The ceiling of the enclosure was a large rectangular sheet-metal hood, with an exhaust duct in the 

center. Two sides of the enclosure had single swinging doors for personnel access, and a third 

side had double swinging doors through which the mold could be wheeled. Three sides of the 

enclosure had small (roughly 1 foot by 2 feet) openings at the bottom, for inlet air. Fabrication 

occurred near the side without an inlet air opening. Within the enclosure, two air registers were 

placed in a manner such that the registers would direct streams of recirculated air from near the 

ceiling, down across the faces of the mold. These two air blowers were used to simulate air flow 

patterns in typical production fabrication facilities. 

Exhaust air from the enclosure was carried through a nominal 12-inch diameter duct, 

running parallel to the ceiling of the room in which the enclosure was located. Sampling probes 

for a total hydrocarbon (THC) analyzer, gas chromatograph, and an S-type pitot tube (for 

velocity measurements) were inserted into the duct. 

Output from the total hydrocarbon analyzer was fed into a Dow computer system, and 

analyzed by Dow "Camille" computer software. 

The hand layup and gel coat spraying operations were conducted on a male mold with 

three faces. The total surface area for the three faces was 30 square feet. In addition to the three 

surfaces, a 9-inch wide flange ran around the entire outer perimeter of the mold. Overspray and 

resin run-off from the fabrication surfaces were deposited on this flange. A sketch of the mold is 

given in Figure 1. The mold was made of steel, and placed on a wheeled cart, such that the 

bottom of the mold was approximately 1 foot above the floor. The total weight of the mold and 

the cart were approximately 630 pounds. 

H 
P.6 

The spray equipment consisted of a Binks model B5 pumping system, with a cart and 

boom extension arm, and a Binks model 102-2400 external mix air- assisted airless spray gun. 

The weight of the complete spray system (including cart and boom) was approximately 410 

pounds. 

A platform floor scale was used to weigh both the mold and the pumping system. The 

platform scale had a digital readout, with a maximum reading of 1000 pounds, and a minimum 

reading of 0.1 pounds. During testing, it was observed that the scale reading did not always 

return to "0.0" after a measurement. Instead, the scale might reading 0.1 or "-0.P. Likewise, 

repeated measurements of the mold or spray system might vary +/- 0.1 pounds from a given 

value. 

2.2 DAY 1 - HAND LAY-UP TEST 

A test run was made of hand lay-up emissions. The hand lay-up process involved use of 

chopped strand fiberglass mat, to which catalyzed resin was applied. The catalyzed resin was 

applied with a paint roller that had been dipped into a resin bucket. After the catalyzed resin was 

rolled onto the fiberglass mat, the catalyzed resin and mat were "rolled out" with a metal roller to 

assure that no air voids existed in the laminate. 

Mr. Bahner's notes on the hand lay-up run indicate a start time of 13:07:00 (1:07 p.m.). 

The notes further indicate that one face of the laminate was complete at 13:11:30, a second face 

was complete at 13:16:00, and the final face was completed at 13:29:15. This represents a total 

lamination time of 22 minutes and 15 seconds. This was followed by a curing period of 

approximately 100 minutes. Total hydrocarbon analyzer measurements were stopped at 

15:13:56, representing a total elapsed time from the beginning of lamination of approximately 

127 minutes. Table 1 lists the fabrication parameters during the hand lay-up test. 

2.2.1 Calibration Gases. 

Dow used four (non-zero) calibration gases, and one zero gas. The calibration gases were 

styrene, with the balance in nitrogen. The four calibration gas concentrations (in parts per 

million (ppm)) were: 

1) 354 ppm (full-span gas) 

2) 283 ppm 

3) 164 ppm 

4) 104 ppm 

5 
P.7 

Dow personnel noted the total hydrocarbon analyzer response was not completely linear, 

because a midrange gas was about 7 percent above a linear calibration line (the other three 

calibration gases were within 5 percent of a linear calibration line). Method 25A includes a 

requirement that instrument response be within 5 percent of linear for all calibration gases. Mr. 

Banner stated that this exception to Method 25A should be noted in the test protocol. 

2.2.2 Total hydrocarbon analyzer traces. 

Mr. Banner recorded total hydrocarbon analyzer readings, S-type pitot probe readings, 

and comments on fabrication activities during the hand lay-up test. Figure 2 shows a comparison 

of emissions concentrations as recorded by Mr. Banner, compared to emission concentrations 

recorded by the Camille computer system (at the time of Mr. Bahner's recordings). 

Mr. Bahner's recorded concentrations were based on a full-scale reading taken to be 350 ppm. 

The correlation between the two concentration traces appears good. For the approximately 80 

readings taken by Mr. Bahner, Mr. Bahner's readings were, on average, 9 percent below the 

values recorded by the Camille system. It appears, from Figure 2, that there may have been a 

time difference between the Dow Camille system and Mr. Bahner's hand recordings. 

Specifically, it appear's that Mr. Bahner's recording were a fraction of a minute later than 

equivalent Dow Camille readings. Therefore, the actual agreement between the Dow Camille 

system and Mr. Bahner's recordings may be much closer than within 9 percent. 

Figure 3 depicts total hydrocarbon analyzer emission concentrations recorded by the Dow 

Camille computer system for the entire hand lay-up run. Figure 3 includes notations indicating 

the time period when lay-up operations were occuring, and the subsequent curing period. 

2.2.3 Background concentrations, and end-of-run considerations. 

Non-zero background concentrations were observed on both the hand lay-up and gelcoat 

spraying test days. For the hand lay-up run, a background concentration of 1.01 ppm was 

observed in the four minutes prior to the start of the run. This compares to an average 

concentration of 10.36 parts per million over the approximately 127 minutes of the hand lay-up 

run. 

The hand lay-up run and gel coat spray run were both terminated before concentrations in 

the sampling duct returned to the background concentration achieved before the testing. It will 

be necessary during actual testing to assure that measurements return to pre-test values prior to 

terminating runs, or to account for the additional mass that would be associated with continuing a 

run until measurements reach pre-test conditions. Figure 5 shows a trace of cumulative emissions 

versus time for the total hydrocarbon analyzer on the hand lay-up run. It can be seen that the 

curve is still increasing slightly at the end of the run. 

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P.8 

2.2.4 Mass balance measurements. 

Prior to the hand lay-up run, heavy-duty paper was put down under the mold to catch any 

resin that dripped off the mold during the lamination (hand lay-up) procedure. 

Mass measurements for the hand lay-up run were as follows: 

1) 7.4 pounds (Mass of resin used) 

2) 640.2 pounds (Mass of mold plus laminate plus paper, after curing) 

- 633.5 pounds (Mass of mold plus paper, before lay-up) 

6.7 pounds (Cured resin on mold or paper) 

3) 7.4 pounds (Mass of resin used) 

- 6.7 pounds (Cured resin on mold or paper) 

0.7 pounds (Mass loss, i.e., styrene emitted) 

From these measurements, it was clear that the measurements of mold mass before and 

after lamination were problematic. If, for example, the readings of the mold mass before and 

after lamination were both taken to be accurate to ± 0.1 pound, the calculated cured resin on the 

mold could vary from 6.5 pounds to 6.9 pounds. This would therefore result in a calculated 

mass loss of 0.5 pounds to 0.9 pounds; a very large range. 

2.2.5 Emission measurement results. 

Table 2 contains comparisons of the calculated hand lay-up emissions for the different 

measurement methods. The total hydrocarbon analyzer produced the lowest calculated emissions. 

The gas-chromatograph produced higher calculated emissions. The mass-balance method 

produced higher calculated emissions than either of the direct emission measurement methods. 

The accuracy of the three methods cannot be definitively assessed from this data. 

However, the accuracy of the mass balance measurement method is probably limited by the 

repeatability the mold mass measurements, and the accuracy of the gas chromatograph method 

may be limited by the fact that the gas chromatograph does not sample continuously. Therefore, 

it appears that the total hydrocarbon analyzer measurement is probably the most accurate 

measurement. 

1 
P.9 

2.2.6 Comparison of emissions (calculated from THC analyzer measurements) with AP-42 

emission factors. 

Table 2 indicates that the emission factor for hand lay-up (calculated from total 

hydrocarbon analyzer data) was measured to be 17.0 percent of available styrene. This value is 

higher than the AP-42 emission factor of 5 to 10 percent of available styrene (for hand lay-up of 

a non-vapor-suppressed resin). In fact, if the 7.5 percent midpoint of the AP-42 emission factor 

range is utilized, the ratio between the measured value and the AP-42 midpoint is 2.27. This 

ratio is comparable to the ratios found when comparing other recent test results for gel coating 

and spray lay-up with AP-42 emission factors (see Appendix A). 

2.3 DAY 2 - GEL COAT SPRAYING TEST 

A test run was made of gel coating spray emissions. Mr. Bahner's notes on the run 

indicate that spraying started at 11:28:29. The top face of the mold was sprayed for 

approximately 30 seconds. This was followed by a pause of approximately 30 seconds. Then the 

side face of the mold was sprayed for approximately 15 seconds. This was followed by a pause 

of 5 seconds. Then the front face of the mold was sprayed for 32 seconds. After a pause of 20 

seconds, touch-up spraying of all mold faces lasted approximately 18 seconds. This results in a 

total spray time of 95 seconds, over a period of 2.5 minutes. The mold was allowed to cure for 

approximately two hours, until the total hydrocarbon analyzer was shut off at 13:31:57, resulting 

in a total run time of over 123 minutes. The test conditions for the gel coat spraying run were as 

shown in Table 3. 

2.3.1 Duct flowrate verification 

Prior to testing, Mark Bahner made measurements of the duct dimensions and air flow 

velocity inside the duct. These measurements were made at a single damper setting, 

corresponding to a nominal flowrate of 1600 cubic feet per minute (cfm). A total of six velocity 

measurements within the duct with a hot-wire anemometer produced an average duct velocity of 

2058 feet per minute (fpm). A measurement of the outside duct circumference produced a value 

of 38 3/16". This corresponds to an outside duct diameter of 12.155", and an inside duct 

diameter of 12.030" (for a duct wall thickness of 1/16"). A duct velocity of 2058 fpm and an 

inside diameter of 12.030" results in a calculated flowrate of 1624 cfm. This is in close 

agreement with a value of 1638 actual cubic feet per minute (1647 standard cubic feet per 

minute) measured by Dow on July 8, 1993 (see Appendix A). 

Dow used a single-point S-tube probe as verification that flow inside the duct remained 

constant during testing. Mark Bahner recommended that the S-tube reading be recorded 

frequently during testing, to assure that air flow remained constant. (Mr. Bahner recorded values 

during the hand layup testing of 0.56 ± 0.01 inches of water. This reading is compatible with a 

flowrate of approximately 1600 cfm. 

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P.10 

2.3.2 Sampling system leakage considerations. 

Dow personnel noted that sampling system leakage tests had been run immediately after 

the sampling system had been installed. Mr. Banner noted that sampling system integrity could 

be checked by closing sampling lines, and observing that sampling pressure went to zero. This 

method would also verify that the total hydrocarbon analyzer pump diaphragm had not developed 

a leak. Verification that the sampling system does not have in-leakage assures that sampling 

system in-leakage does not cause undermeasurement of emissions. 

2.3.3 Total hydrocarbon analyzer traces 

A graph of the total hydrocarbon analyzer readings, as recorded by the Dow "Camille" 

computer system, for the gel coat spraying run of 1/5/95, is shown in Figure 5. Figure 6 shows 

these readings for the first 5 minutes only, and includes notations of the spraying operations being 

conducted during this time. Both figures show that the emission rate (exhaust stream 

concentration) drops off after spraying is completed. An analysis of Figure 6 indicates that there 

is a time delay of approximately 30 seconds to one minute between spraying episodes and 

resulting increases in concentrations recorded at the duct. This delay is believed to result from 

the times required for the styrene plume to travel to the sampling point, and the time required for 

the sampled gas to travel to the instrument. 

2.3.4 Background concentrations, and end-of-run considerations. 

Non-zero background concentrations were observed on both the hand lay-up and gelcoat 

spraying test days. For the gel coat spraying run, a background concentration of 0.43 ppm was 

observed prior to the start of the run. This compares to an average concentration of 10.70 ppm 

over the approximately 123 minutes of the gel coat spraying test run. 

The hand lay-up run and gel coat spray run were both terminated before concentrations in 

the sampling duct returned to the background concentration achieved before the testing. It will 

be necessary during actual testing to assure that measurements return to pre-test values prior to 

terminating runs, or to account for the additional mass that would be associated with continuing a 

run until measurements reach pre-test conditions. Figure 7 shows a trace of cumulative emissions 

versus time for the total hydrocarbon analyzer during the gel coat spraying run. It can be seen 

that the curve is still increasing slightly at the end of the run. 

2.3.5 Mass balance measurements. 

Prior to the gel coat spraying run, heavy-duty paper was put down under the mold and on 

the sides of the enclosure, to catch any resin that dripped off the mold during the gel coat 

spraying procedure. 

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P.11 

Mass measurements for the gel coat spraying run were as follows: 

1) 415.8 pounds (Spray rig, before spraying) 

- 411.9 pounds (Spray rig, after spraying) 

3.9 pounds (Total gel coat sprayed) 

2) 639.3 pounds (Mass of mold plus gel coat plus paper, after curing) 

- 636.2 pounds (Mass of mold plus paper, before spraying) 

3.1 pounds (Cured gel coat on mold or paper) 

3) 3.9 pounds (Total gel coat sprayed) 

- 3.1 pounds (Cured gel coat on mold or paper) 

0.8 pounds (Mass loss, i.e., styrene emitted) 

2.3.6 Emission measurement results 

Table 4 contains comparisons of the calculated gel coating emissions for the three 

different test methods. The total hydrocarbon analyzer produced the lowest calculated 

emissions. The gas-chromatograph produced higher calculated emissions. The mass-balance 

method produced higher calculated emissions than either of the direct emission measurement 

methods. 

The accuracy of the three methods cannot be definitively assessed from this data. 

However, the accuracy of the mass balance measurement method is probably limited by the 

repeatability the mold mass measurements, and the accuracy of the gas chromatograph method 

may be limited by the fact that the gas chromatograph does not sample continuously. Therefore, 

it appears that the total hydrocarbon analyzer measurement is probably the most accurate 

measurement. 

2.3.7 Comparison of emissions (calculated from THC analyzer measurements) with AP-42 

emission factors. 

Table 4 indicates that the emission factor for gel coat spraying (calculated from total 

hydrocarbon analyzer data) was measured to be 41.2 percent of available styrene. This is higher 

than the AP-42 emission factor range of 26 to 35 percent of available styrene. Other recent test 

results have also indicated gel coat spraying emission factors that are higher than AP-42 (see 

Appendix A). 

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2.3.8 Gel coat overspray observations. 

After the gel coat spraying run was completed, Mr. Bahner performed a visual inspection 

of the gel coat spraying patterns on the mold. It was noted that the gel coat did not completely 

cover the entire portion of the mold within the area marked off with masking tape for coverage. 

Additionally, the overspray on the 9-inch flange surrounding the mold was evaluated. The 

overspray was found to be relatively heavy for the inside 2-4 inches of the flange, relatively light 

out to seven inches, and virtually no overspray was seen on the outside two inches of the flange. 

Mr. Bahner judged this to be much less overspray (i.e., a much more careful spraying job) than 

occurred at production facilities he had visited. 

2.4 ALTERNATIVE METHODS OF EXPRESSING EMISSION FACTORS 

Table 5 presents total hydrocarbon analyzer emission test results for hand lay-up and gel 

coating. These results are expressed as emission factors in three different forms: 

1) Emissions as a percentage of initial available styrene (i.e., emissions of styrene in 

pounds per 100 pounds of initial available styrene), 

2) Emissions as a percentage of initial resin mass (i.e., emissions of styrene in pounds 

per 100 pounds of initial resin), and 

3) Emissions in grams per square meter of mold application surface. (For this 

calculation, the mold application surface was taken to be 30 square feet.) 

8 

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3.0 CONCLUSIONS 

1) Concentrations as recorded by the Dow "Camille" computer system are in close agreement 

with measurements recorded by hand, indicating that there are no programming errors in 

the Camille computer system. 

2) Volumetric flowrate in the exhaust duct as measured by RTI with a hot-wire anemometer 

is in close agreement with flowrate measured by Dow. Flow appears very stable over 

time. 

3) For both hand lay-up and gel coat spraying, emissions as measured by the total 

hydrocarbon analyzer were the lowest of the three emission measurement methods 

evaluated. Gas chromatograph measurements were higher, and mass balance-based 

calculated emissions were highest. This testing did not provide definitive results on which 

test method was most accurate. However, the gas chromatograph measurement method 

provided only intermittent (not continuous) sampling, and the precision of the scale used 

for the mass balance was probably not sufficient to provide highly accurate emission 

calculations (see conclusion #4, below). Therefore, the total hydrocarbon analyzer may 

have been the most accurate measurement method. Further evaluation of the accuracy the 

total hydrocarbon analyzer measurement method is recommended. 

4) The precision of mass-balanced based emission measurements is low, due to a scale with a 

least significant digit of 0.1 pound, emissions of less than 1 pound, and scale hysteresis. 

5) Emission factors as calculated from all measurement methods were higher than AP-42 for 

both hand lay-up and gel coat spraying. For hand lay-up, emission factor calculated from 

the total hydrocarbon analyzer/Camille computer emission measurement method was 17.0 

percent of available styrene. This compares with an AP-42 (1988 revision) emission factor 

of 5 - 10 percent for hand lay-up of non-vapor-suppressed resins. For gel coat spraying, the 

emission factor calculated from the total hydrocarbon analyzer/Camille computer emission 

measurement method was 41.2 percent of available styrene. This compares with an AP-42 

(1988 revision) emission factor of 26 - 35 percent for hand lay-up of non-vapor-suppressed 

resins. 

The results of this preliminary testing were in general agreement with other recent test results 

(see Appendix A) mat yield higher emission factors than found in AP-42. 

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P.14 

4.0 RECOMMENDATIONS 

1) Prior to formal testing, a preliminary experiment should be conducted in which the mass 

balance method is the reference standard (i.e. styrene evaporation from a static system, 

using a scale with increased resolution compared to the scale used in this testing). This 

preliminary experiment will establish the accuracy of total hydrocarbon analyzer and gas 

chromatograph emission measurement methods. The test will also confirm mat the capture 

efficiency of the enclosure is near 100 percent. 

2) During formal testing, it will be necessary to verify that background concentrations are low 

and stable prior to a test run. Further, it will be necessary to assure that curing is allowed 

to continue to the point at which concentrations within the exhaust duct return to pre-test 

conditions. 

3) Future gel coat emissions testing should be run with spraying to the outside edge of at least 

one side of the mold flange. Alternatively, spraying should be to within 1-3 inches of the 

edge of several sides of the mold flange. These spraying situations are probably more 

representative of conditions at most production plants. 

4) It is recommended that sampling system leak checks be performed at fixed intervals (daily 

or weekly) during the formal testing. Leak checks will assure that emissions are not undermeasured due to air in-leakage into the sampling lines or instrument. 

5) One method to increase the precision (accuracy) of the mass balance method is to use a 

scale with increased resolution. Use of a scale with increased resolution (below 0.1 pound) 

should be investigated. For example, RTI has identified a scale (Model F150S) that can 

measure to 330 ± 0.002 pounds, which can be rented from Sartorius Company for $100 

per week (contact Bob Young at 800-645-3108). Another scale, Model F300S, can 

measure to 660 ± 0.02 pounds, and can be purchased from Sartorius for $4,195. If the 

Model F150S is used, changing to a lighter mold would be required. If the 630 pound 

mold is required for generating baseline emission measurements, a separate comparison of 

the mass balance method with direct emission measurements might be performed with a 

lighter mold. 

10 

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P.15 

Table 1. Parameters for hand lay-up test. 

Factor 

I Ambient Air Velocity 

1 Initial Styrene Content 

Gel Time 

Laminate Thickness 

Value 

"Low" (nominally 50 feet per minute across 

the mold surface). 

"High" (42 percent) 

"Fast" (target of 15 minutes, to be achieved 

with methyl ethyl ketone peroxide Hi-Point j 

90 catalyst, at a concentration of 1.5 E 

percent) j 

"Thin" (one layer of 1.5 ounce chopped J 

strand mat). [ 

Additional Notes: 

1) Ambient air temperature (as recorded by Dow): 68-70 degrees Fahrenheit. 

11 

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P.16 

Table 2. Hand Lay-up Emission Test Results 

1 Measurement 

I Method 

Total Hydrocarbon 

Analyzer 

(Dow "Camille" 

system) 

Total Hydrocarbon 

Analyzer 

(Mr.Bahner's 

recorded 

1 measurements) 

| Gas Chromatograph 

B Mass Balance 

Emission 

(Pounds) 

0.528 

0.483 

0.611 

0.7 

Emission Factor 

(Percent of 

Available Styrene) 

17.0 

15.5 

19.7 

22.5 

Percent Difference 

(from total 

hydrocarbon 

analyzer read by 

Dow "Camille" 

system) 

No Difference 1 

- 9 

+ 16 

+ 32 

Note: AP-42 emission factor for non-vapor-suppressed resin in hand lay-up is 5 to 10 percent of 

available styrene. 

12 

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P.17 

Table 3. Parameters for gel coat spraying test. 

Factor 

Ambient Air Velocity 

Initial Styrene Content 

1 Gel Time 

Gel Coat Thickness 

|J Spray gun delivery rate 

Value 

"Low" (nominally 50 feet per minute across 

the mold surface). 

"Low" (35 percent) 

"Fast" (target of 10 minutes) 

"Thick" (target value of 24 mils) 

"Fast" (target value of 4 pounds per minute) J 

Additional Notes: 

1) Gun type: Binks Model 102-2400, "external mix". 

2) Spray system: Binks model B5, with pump ratio of 11 to 1 (i.e. 100 psig air pressure 

results in 1100 psig fluid pressure) . 

3) Ambient air temperature: 68.1 F (initial) to 69.7 F (final). 

4) Air assist pressure: 40 psig (static) to 35 psig (delivery). 

5) Pump air pressure: 50-52 psig (static) to 48 psig (delivery). 

With an 11 to 1 pump, this would result in gel coat fluid pressures of 550-572 psig (static) 

to 528 psig (delivery). 

13 

Ir 
P.18 

Table 4. Gel Coat Spray Emission Test Results 

Measurement 

Method 

Emission 

(Pounds) 

Emission Factor 

(Percent of 

Available Styrene) 

Percent Difference 

(from Total 

Hydrocarbon 

Analyzer read by 

Dow "Camille" 

system) 

Total Hydrocarbon 

Analyzer 

(Dow "Camille" 

system) 

0.563 41.2 No Difference 

Gas Chromatograph 0.663 48.6 + 18 

Mass Balance 0.8 58.6 + 42 

Note: AP-42 emission factor for (non-vapor-suppressed) gel coat sprayup is 26 to 35 percent of 

available styrene. 

14 

A 
Table 5. Emission factors for hand lay-up and gel coat spray runs. 

<cA Ol 

Run 

Identification 

Hand lay-up 

(1/4/95) 

Gel coat spray 

(1/5/95) 

Amount of 

resin/gel coat 

applied 

(pounds) 

7.4 

3.1 

Initial Styrene 

Content of 

Resin/Gel Coat 

(percent) 

42 

35 

Emission 

(pounds, as 

determined 

by THC 

analyzer) 

0.528 

0.563 

Emission Factor (as determined by THC analyzer) 

Percent of 

available 

styrene 

(i.e., grams per 

100 grams of 

initial styrene) 

17.0 

41.2 

Percent of resin/ 

gel coat 

(i.e., grams per 100 

grams of initial 

resin/gel coat) 

7.1 

14.4 

Grams per 

square meter 

of 

application 

surface 

86 I 

92 

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Figure 1. Sketch of male fabricating mold with surrounding flange. 

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1) Total fabrication area on mold equals 30 square feet 
Figure 2. Comparison of Dow "Camille" computer versus 

hand-recorded total hydrocarbon analyzer readings. 

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-CAMILLE 

-HAND 

20 30 40 50 60 70 

Elapsed Time 

80 90 

- 1 -

100 110 120 

CAMVHAND Chart 1 TJ 
Figure 3. Total hydrocarbon analyzer trace for hand lay-up 

(hand-recorded values). 

. 00 

0 10 20 

—••4-

30 40 50 60 70 80 90 100 110 120 

Spraying Curing 

Elapsed Time (minutes) 

RANOHAXO.JUC 

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Figure 4. Cumulative mass emission versus time for hand layup run of 1/4795. 

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3 C 0 t 3 C 3 C 

0 100 -

0.000 -

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 

Time elapsed (minutes) 

1-*.«B Chart J 

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Figure 5. Gel coating emissions for run on 1/5/95, 

as recorded by Dow "Camille" computer system. 

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c 

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</> CO l a Pi 

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Figure 7. Cumulative mass emission versus time for gel coat spraying run of 1/5/95. 

8 

U.bUU -

A CAA 

u.ouu -

wi M.>*v\i • 

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c 

3 

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3 

<u rt inn . 

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«= 0 200 -

0 100 -

0.000 

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 

Elapsed time (minutes) 

1-6-98 Chwtl 
P.27 

Appendix A 

Comparison of recent test results to AP-42 emission factors. 

IX 
P.28 

Table A contains a comparison of AP-42 emission factors with emission factors derived 

from more recent (post-1990) testing. The emission factors from recent testing are as calculated 

by Mark Bahner, based on test reports that include both emission results and data on resin and/or 

gel coat consumption. 

Emission factors in Table A are expressed as a percentage of available (initial) styrene. For 

instance, the AP-42 emission factor for (non-vapor-suppressed) gel coat spraying is 26 to 35 

percent of available styrene. This means that if the gel coat were to initially contain 100 grams of 

styrene, 26 to 35 grams of styrene would be emitted. 

In addition to columns containing emission factors, Table A also contains ratios of the 

emission factors calculated from testing to the midpoint AP-42 emission factor. For example, the 

midpoint of the AP-42 emission factor range for gel coat spraying is 30.5 percent of available 

styrene. The emission factor for gel coating calculated from the preliminary CF A/Dow testing at 

Freeport, Texas (January 4-5, 1995) was 41.2 percent, as is documented in this report. The ratio 

between the test result and the AP-42 midpoint factor is therefore 41.2 divided by 30.5, or 

1.4 (rounded to two significant digits). 

A - l 

11 
Table A. Summary of Calculated Emission Factors 

(Expressed as Percentage of Available Styrene) 

i 

^ 

^ 

Emission Factor Source 

AP-42 Emission Factor 

EPA/Southern Research Institute 

(SRI) testing at Eljer Plumbingware 

(now Carolina Classics). 

EPA/Radian (RTP) testing at Venetian 

Marble, VA. 

EPA/Radian (RTP) testing at General 

Marble, NC. 

Radian (Ohio) testing at 

CORTEC, OH. 

Preliminary CFA/Dow testing at 

Freeport, TX (January 4-5, 1995). 

Bison Engineering testing at GEA 

Dynamic Fabricators, ID. 

Gel Coat 

Sprayup 

(NVS)' 

26-35 

66 

68 

97 

42/29* 

41 

Not 

App. 

Ratio to 

AP-42 

Midpoint 

1.0 

2.2 

2.2 

3.2 

1.4/1.0 

1.4 

Not 

App. 

Resin 

Sprayup 

(VS)2 

3 - 9 

16 

Not 

App. 

Not 

App. 

Not 

App. 

Not 

App. 

Not 

App. 

Ratio to 

AP-42 

Midpoint 

1.0 

2.7 

Not 

App. 

Not 

App. 

Not 

App. 

Not 

App. 

Not 

App. 

Resin 

Sprayup 

(NVS)' 

9-1 3 

Not 

App. 

Not 

App. 

Not 

App. 

Not 

App. 

Not 

App. 

24 

Ratio to 

AP-42 

Midpoint 

1.0 

Not 

App. 

Not 

App. 

Not 

App. 

Not 

App. 

Not 

App. 

2.2 

Hand 

Layup 

(NVS)' 

5-1 0 

Not 

App. 

Not 

App. 

Not 

App. 

Not 

App. 

17 

Not 

App. 

Ratio to 

AP-42 

Midpoint 

1.0 

Not 

App. 

Not 

App. 

Not 

App. 

Not 1 

App. 

2.3 

Not 

App. 

1) NVS = Non-vapor-suppressed 

2) VS = Vapor-suppressed 

3) Emission factor of 42 percent for a "baseline" gel coat, and 29 percent for a "high performance" gel coat with a "fast" gel time.