Predictive Service Life Tests for Roofing Membranes

Twelve roofing membranes, including poly [vinyl chloride], asphalt glass-felt built-up, thermoplastic polyolefin, atactic polypropylene polymer modified asphalt, styrene-butadiene-styrene block copolymer modified asphalt, and ethylene-propylene-diene rubber membranes were exposed to oven heat, ultra-violet and condensing humidity environment, and two and four-year outdoor exposure at United States Department of Defense sites in Phoenix, Arizona (hot and dry climate); Key West, Florida (hot and moist climate); and Champaign, Illinois (moderate mid-continent climate). Selected mechanical properties were measured before and after each exposure. Each membrane was rated before and after exposure and the membranes were ranked as to relative performance in these physical tests. The physical tests performed include load-strain, dynamic impact resistance, moisture absorption, and glass transition temperature. Identical test methods were used for each membrane to make the physical properties directly comparable. With the exception of the TPO (thermoplastic polyolefin) membrane samples, the mean changes in the load to first peak of the membranes at each site had a 0.994 correlation with the before exposure, afte