b'onroof the SRO for PVC at MRCA The Midwest Roofing Contractors Assn. (MRCA) has a reputation for being very forward-looking and aggressive in keeping its membership informed on advances in roofing technology. At its Nov., 1981meeting, 1,500 people jammed into the main meeting room at the St. Louis convention center to learn of an extraordinary new document. The standing-room-only crowd witnessed the unveiling of Recommended Performance Criteria for PVC (polyvinyl chloride) single-ply roof membrane systems. This important new technical document was produced through the joint efforts of the MRCA\'s Technical and Research (TCommittee and Rene Dupuis, vice presi&R) dent, Structural Research, Inc., Middleton, Wis. This document is a remarkable first in that it was not developed and issued by the National Bureau of Standards or American Society for Testing and Materials (ASTM). Rather it was the lack of standards from such agencies and groups that spawned MRCA\'s quest for this criteria. Cy Tilsen, former MRCA president and co-chairman of the T &R Committee, remarked that "everyone, including the materials manufacturers themselves, felt an urgent need for performance criteria for single-ply roofing Dick Fricklassystems." Tilsen is president of Tilsen Roofing Co., Madison, Wis. Paul Morris, presiDirector of thedent, Sellers & Marquis Roofing Co., Kansas City, Mo., is the other co-chairman. Roofing Industry EducationalSince it was felt to be technically impossible to write a master performance specificaInstitute {El), RItion encompassing everything from four-ply, hot-applied, built-up roofing systems to Englewood, Colo. diverse materials like elastomeric and loose-laid plastic sheetings, a series of related documents is planned. To create an adequate document,MRCAdirectors decided to fund basic research on test methods as needed. They also backed a literature search of standards existing in Great Britain, Switzerland, West Germany, Canada, Japan and Austria. They had two goals in mind. One was to produce a standard that could lead to good field performance. The other was to discourage the introduction of products that might not succeed in commercial roofings difficult exposures. On Nov.10,I 981 , it happened! The first U.S. standard of its kind was passed out in that crowded meeting room. So far it\'s only a recommended performance criteria covering one family of single plies: the PVC materials. Yet the first is always the most difficult. MRCA is set to move with all possible speed toward developing similar recommended criteria for modified bituminous products, as well as the elastomerics. It intends these criteria to be flexible enough to incorporate technological advances, as well as variations in the basic systems. But the most important thing is this: At last a U.S. developed and written performance criteria is available. Adoption by ASTM and other standards-making bodies is just a matter of time. The document is not perfect and the industry, including the PVC manufacturers, have not yet had the opportunity to study it in detail. The T &R Committee will certainly give all viewpoints a fair and just hearing, and some changes can be expected. Tilsen points out that the very fact thatMRCAhas published a performance criteria is recognition that these materials have made an impact in the marketplace. It is not to be construed as an effort to retard or stop PVCmanufacturers from marketing their systems, he adds. The objective is only to try to help manufacturers establish systems with a reasonable chance of succeeding. There is ample evidence that, based on today\'s state of the art, this document (number MP-10, available from MRCA for $1) has been well-thought-out and carefully prepared. A giant stride has been made toward improving U.S. roofing technology. Editor\'s Note: See RSI News., p.16,for a related story on this document. RSI-January, 1982'