SAN DIEGO — Two different forms of polystyrene — expanded and extruded — have new life in attacking polyisocyanurate's dominance for insulation used directly over steel structural-roof decks. A roofers' trade group, however, is concerned about the implications of new PS marketing messages, and a polyisocyanurate association continues to differ with the PS community on controversial fire-safety issues.
An International Conference of Building Officials subsidiary recognized an expanded PS system from Premier Industries Inc.'s Insulfoam division in January and the extruded PS Deckmate foam products from Dow Chemical Co. in February.
The recognitions — incorporating several caveats and thickness and density maximums — allow installation of either insulation without a thermal barrier and can save up to 10 percent on that portion of a roofing job.
ICBO caveats on PS insulation include flame-temperature limits, installation of a wet-pipe automatic fire-extinguishing system, prohibition on reroofing on top of PS insulation and mandatory product labeling.
An early 1950s fire at a 53-acre General Motors Corp. plant in Livonia, Mich., prompted more- sophisticated tests, and agencies began requiring roof thermal barriers in the 1970s for consistency with other code provisions.
The new developments generated reaction at the Expanded Polystyrene Molders Association annual conference and exposition, held March 7-9 in San Diego in conjunction with the Alliance of Foam Packaging Recyclers.
"Direct-to-deck is a hot issue these days," said Kevin Farrell, president of both the Crofton, Md.-based EPS association and block molder Tri State Foam Products Inc. of Martinsville, Va.
Suppliers of competitive materials may use extreme means to maintain control of a market niche, said Richard Nickloy, president of EPS foam manufacturer Contour Products Inc. of Kansas City, Kansas.
The Washington-based Polyisocyanurate Insulation Manufacturers Association views its fire-safety stance as more than a competitive issue.
"A lot of things are thrown at us, but PIMA got involved because of its knowledge about the roofing industry and our concern about appropriate use of materials," President Jared Blum said in a telephone interview.
The National Roofing Contractors Association of Rosemont, Ill., said polyisocyanurate accounted for 44.3 percent of the insulation in low-slope roofs during 1998.
Expanded PS accounted for 10.1 percent of the low-slope market, and extruded PS, 3.2 percent. The domestic market survey included typical cover boards; perlite and wood fiberboard had, respectively, 17.8 percent and 15.8 percent.
Douglas Sobek, an Insulfoam spokesman, said ICBO's approval will help Tacoma, Wash.-based Premier compete in the single-ply roofing market.
`The PS industry has been trying for about three years to change some fire codes. Previously, we had to put a 15-minute [thermal] barrier between our foam and the steel deck to meet the uniform code."
He added: "Acceptance from ICBO pretty much paves the way" with other code agencies. An overall EPS system without the thermal barrier saves a contractor 8-10 percent, making the Insulfoam-brand material "less expensive than [polyisocyanurate]," he said.
Premier employs 850, had 1999 sales of $110 million and anticipates reaching $150 million this year, Michael McKenna, senior vice president, said in an interview. "We intend to double that in the next three years."
The Insulfoam division, accounting for 70 percent of Premier sales, has plants in Kent, Wash.; Anchorage, Alaska; the Dalles, Ore.; Chino and Dixon, Calif.; West Valley City, Utah; Phoenix; Aurora, Colo.; Albuquerque; Mead, Neb.; and Columbus, Ohio.
Wayne Petersen, senior North American architectural market manager with Dow in Midland, Mich., said ICBO approval means that Styrofoam Deckmate and Deckmate Plus-brand insulation is now accepted by all the major code bodies for use directly on steel roof decks.
Other code bodies include the Building Officials and Code Administrators, Southern Building Code Congress International and Underwriters Laboratories Inc.
Eliminating the thermal barrier may save roofers 10 percent, but extruded PS is still more expensive than polyisocyanurate, Petersen said in a telephone interview.
Four large companies make extruded PS foam, while the molded foam community consists of many producers. Dow introduced extruded PS foam board in 1940.