This wasn’t the first time OSHA required testing to prove these theories. In the genesis of the process, Miles conducted a spray test at his worksite in an oven the size of a spray booth to prove that the spray method wouldn’t reach high levels of emissions, even on a hot summer day. “We conducted tests with a number of different gel coat guns and chopper guns and ran the tests in this oven with no ventilation, no fan whatsoever. Then, we started turning the heat up and turning the temperature up to 120 degrees. The highest concentration we could get was 650 parts per million under the worst conditions,” says Miles.
To update their findings, the consortium hired Hughes Associates, a consulting firm from New Jersey who has worked with the composites industry on other fire protection issues. Joe Scheffey, director of research and development at Hughes, looked at many areas during this evaluation.
“We looked at general manufacturing processes, fire suppression and light safety features like sprinklers and exits. All of them had an adequate fire suppression system,” says Scheffey. In addition, the firm looked at the chemicals and additives used, the styrene content of the resins, the electrical equipment, spray guns and equipment, cleanup process, and ventilation systems.
Their findings supported the cause. In these tests, Hughes maintained vapor concentration under various scenarios, ranging from 6.8 to 17.8 percent. In normal conditions, the average concentration was 7.3 percent. In any case, it was well below the 25 percent required by OSHA.
ACMA also borrowed a testing facility at Purdue University and conducted its own testing by replicating worst-case scenario spray operations. “We used the most volatile resins, turned the spray gun pressures way up, we increased temperature and turned off blowers so there was no fresh air coming in,” says Schweitzer. “What we determined was that even under worst-case operations, we couldn’t achieve an explosive mixture in the air.”