- Author
- Mathey, R. G. | Rossiter, W. J.
- Title
- Properties of 21 Year Old Coal-Tar Pitch Roofing Membranes: A Comparison with the NBS Preliminary Performance Criteria.
- Coporate
- National Bureau of Standards, Washington, DC
- Report
- NBSIR 77-1256, June 1977,
- Distribution
- Available from National Technical Information Service
- Keywords
- roofs; construction materials; membranes; pitch (material); coal tar; aging tests (materials); visual inspection; buildings | visual inspection
- Identifiers
- roofing materials
- Abstract
- The properties of coal-tar pitch roof membranes approximately 21 years old were compared to the properties reported for such membranes in NBS Building Science Series 55, 'Preliminary Performance Criteria for Bituminous Membrane Roofing.' Samples of the old membranes were taken from eight buildings having roof areas that range from 0.5 to 1.5 million square feet (4.6 to 15 sq km). The buildings were located at three sites in or near the state of Kentucky. The roof membranes on these buildings had been subjected to different maintenance procedures. Laboratory tests conducted on 47 membrane samples included tensile strength, modulus of elongation and coefficient of expansion. The thermal shock factor was calculated for each sample. Laboratory observations were made of the membrane samples to determine between-ply bitumen thickness, weight per unit area, ply adhesion, pliability and condition of the membrane.