Maeger, Vanspeybroeck, Lamborn, Mamoun, Leevers, Oliphant
Material Science RCP # 2006 Washington DC
As polyethylene pressure pipes enter the global marketplace under an ever-wider range of operating conditions, there is increasing emphasis on their rapid crack propagation performance. It is important that both producers and end-users are able to rely on the robustness of the rapid crack propagation test results and on their relevance to service conditions. The round robin evaluations needed to underpin the S4 test method pre-dated the first edition of ISO 13477. Since then, PE materials have continued to improve, and some aspects of the method (e.g. techniques for generating an initial fast crack) are becoming an increasing challenge. This paper presents results from a new round robin; involving tests on commercially extruded 8-inch SDR11 black PE 80 (PE 3608) and 8-inch SDR11 black PE 100 (PE 4710) pipes (which meet the minimum wall thickness specified in ISO 4437 for gas distribution). Four laboratories, including three commercial labs, tested each pipe independently. The results are discussed in terms both of test methodology and of data consistency.