Researchers have learned how to measure styrene emissions from uncontrolled open molds accurately and with good repeatability. The effort meets a milestone of an industry regulatory program involving the reactive monomer styrene and, long-term, will improve conditions for fabricators who spray unsaturated polyester and vinyl ester resins in making composite parts.
``The factors which contribute to emissions have been identified, and accurate emissions levels have been established for baseline operating scenarios,'' the Composites Fabricators Association project team concluded in its Phase I final report.
CFA mailed an abridged 64-page version to its 700 member companies in mid-September and is selling copies of the full report.
Robert Lacovara, CFA technical director, and Dow Chemical Co. associates Larry Craigie, Terry Cowley, Paul Wykowski and Gary Webster conducted the baseline study on hand lay-up, gel coating and spray-up procedures.
Sixty experimental runs were done between Sept. 19 and Dec. 14, 1995, in a temporary, total enclosure at Dow's composites applications laboratory in Free-port, Texas.
A subsequent gel-coat/spray-up optimization study concluded that proper spray gun set-up and spraying techniques ``should be the first line of pollution prevention and source reduction in polyester/vinyl ester resin spraying operations,'' the report said.
Keys include sizing spray tips correctly, adjusting the gun's pressure to the lowest possible level, training operators adequately, improving spraying techniques and capturing off-spray.
Researchers began Phase II in May and have completed 36 runs with plans to conduct 20-28 more.
Researchers are evaluating the impact of larger molds and source-reduction methods in-cluding styrene suppressants, filled systems and alternative application treatment.
McLean, Va.-based CFA opened a dialogue with the Environmen-tal Protection Agency shortly after passage of the Clean Air Act of 1990. The EPA regulates sty-rene as a hazardous air pollutant and will use the current research as a basis for public discussion and in development next year of a maximum-available-control-technology standard for the open molding composites industry.
CFA and the EPA's office of air quality planning and standards in Research Triangle Park, N.C., agreed in 1993 on a program to test emissions of styrene.
Beginning in 1994, the project team developed procedures, apparatus, techniques and a quality-assurance plan to meet EPA requirements for a Category II emission study.
A 1987 Occupational Health and Safety Administration rule said the principal health effects due to styrene exposure involve certain transient central nervous system effects.
Lacovara and Craigie will discuss the research, and Stephen McNally, CFA government affairs director, will review the regulatory implications Oct. 2 as part of CFA's four-day annual convention and exposition at the Wyndham Anatole Hotel in Dallas.