Understanding the Puncture Resistance of Thermoplastic Polyolefin Membranes
SourceThermoplastic polyolefin (TPO) roofing membranes have seen widespread acceptance as they have proven their weathering performance. TPO membranes have been defined by ASTM D6878, Standard Specification for Thermoplastic Polyolefin Based Sheet Roofing, which was developed by Subcommittee D08.18 on Non-Bituminous Organic Roof Coverings. It sets both minimum thresholds for accelerated aging tests and physical property specifications. However, it does not address puncture or impact resistance. In general, puncture resistance is ill-defined for single-ply membranes. This paper examines different modes of membrane puncture, including by hail impact. Various membrane thicknesses, substrates, and attachment methods have been studied. The results are described, and implications for better performing systems are discussed.