INDUSTRY COALITION FORMED TO ADDRESS CHANGES TO FM GLOBAL PROPERTY LOSS PREVENTION DATA SHEET 1-29 

In January 2006, FM Global made significant changes to Property Loss Prevention Data Sheet 1-29 titled “Roof Deck Securement and Above-Deck Roof Components.” The changes particularly affect the design of fully adhered roofing systems that require a Class 1-90 rating or higher on steel decks. Fully adhered systems are defined as hot applied built-up and modified bitumen membranes, torch applied modified bitumen membranes, cold process built-up and modified bitumen membranes, self-adhering modified bitumen membranes and single-ply membranes, and fully-adhered single-ply membranes installed over mechanically-attached insulation, with or without a cover board, on a steel deck. Before this change, the requirements for perimeter and corner attachment could be met by simply increasing the number of fasteners in the perimeter and corner areas for listed systems.

The newly revised Data Sheet 1-29 now states that this prescriptive method of increasing the fasteners in the perimeter and corner areas (bld)cannot be used(endbld) for fully-adhered roof systems requiring a wind uplift rating of Class 1-90 and above. Instead, these roofing systems must meet higher tested ratings for the perimeter and corner areas. No engineering rationale for this change was given, and very few fully-adhered roofing systems comply with this new requirement. These changes effectively eliminated the use of the fully-adhered systems described above requiring a Class 1-90 or higher classification on steel decks where the system must comply with Loss Prevention Data Sheet 1-29.

In addition, the newly revised Data Sheet requires the minimum number of fasteners in the perimeter and corner areas for Class 1-60 and Class 1-75 listed systems to be increased 50- and 100-per cent, respectively, over the number of fasteners in the field of the roof. Loss Prevention Data Sheet 1-29 still allows prescriptive enhancement of perimeter and corner areas for mechanically-attached membranes, including mechanically-attached base sheets in multi-ply asphaltic systems. For these systems, the number of fasteners in the perimeter and corner areas can be prescriptively increased as previously allowed.

These changes were made without prior notice to the roofing industry. ARMA, CFFA, ERA, NRCA, PIMA, RCI and SPRI have formed a coalition of interested parties and are considering ways to address the implications of these changes. The coalition’s goal is to develop recommendations for wind performance and how it can be properly accounted for to assist roofing designers, roofing contractors, roof consultants, property owners, material manufacturers and other interested parties.

In addition, the coalition will focus on educating the roofing and specifications community about the requirements for wind uplift resistance and the determination of these building code requirements in accordance with the appropriate engineering standard from the American Society of Civil Engineers, entitled ASCE 7, (itals)Minimum Design Loads for Buildings and Other Structures.(enditals)