Control of styrene vapor in a large fiberglass boat manufacturing operation

An evaluation of a control system for worker protection from styrene vapor was performed at a manufacturer of large fiberglass reinforced plastic yachts. The manufacturing operations included five tiltable boat hull mold stations. Each station had a floor air slot located beneath the mold which was exhausting about 17 000 CFM. The building had an overall ventilation rate of 10-15 air changes per hour. An attempt was made to improve the performance of this control system by blowing air into the hull mold and by blocking air flow from the back of the mold to induce greater flow from the front of the mold. Consecutive short term breathing zone samples were collected in an effort to show the effect of different job tasks and work modes on exposures. ANOVA was performed to determine levels of significance of several variables. A significant exposure difference was found between right and left tilts of the 46-foot hull mold. The TWA styrene exposure values for the 3-day period of the 4 hull lamination workers were low, ranging from 17 ppm to 25 ppm, and demonstrating that styrene levels can be effectively controlled by means of strategically located high volume exhaust vents for the process studied.