Since early in its involvement with the roofing industry, the spray polyurethane foam (SPF) industry has been active within the U.S. standards community. The current ASTM International standard, ASTM C1029, "Standard Specification for Spray-Applied Rigid Cellular Polyurethane Thermal Insulation," covers the types and physical properties of SPF intended for use as thermal insulation. SPF materials categorized within ASTM C1029 are used for multiple types of SPF products, including roofing materials, wall insulation and storage-tanker insulation.
The standard's physical properties are based on foams using chlorofluorocarbon (CFC-11) as a blowing agent. These foams were phased out in 1993. The current blowing agent is hydrochlorofluorocarbon (HCFC-141b), which will be phased out Jan. 1, 2003. A new blowing agent will be used for the next generation of SPF-based roof systems.
However, the SPF currently used in roofing applications does not meet ASTM C1029 requirements. The SPF industry is taking a two-pronged approach to ensure current SPF-based roof system materials are within the parameters of ASTM specifications by revising the minimum properties within ASTM C1029 and developing a material standard for SPF specifically used for roof systems.