Additives # 2006 Washington DC
With the implementation of NSF Protocol P171 in 1999, and subsequent adoption of ASTM F 2023 in 2000, Miner’s Rule has been used extensively in developing estimations of crosslinked polyethylene (PEX) pipe lifetimes when exposed to varying system conditions in the presence of chlorinated water. Previous work in this area demonstrated that Miner’s Rule can be effectively used and validated for some polyolefins under standard hydrostatic test conditions, but that significant deviations can also occur depending on the material. This paper presents the results of similar work towards a validation method for Miner’s Rule, specifically focused on flowing systems with an aggressive water matrix to accelerate oxidation of the polymer. The use of Miner’s Rule proved to be a reasonable approximation for some materials, but as with the earlier work, overly optimistic for other materials. The paper also discusses the proposed method to be incorporated into the applicable ASTM products standards for PEX and polypropylene (PP) piping and minimum criteria established.
Author(s) : J.HASSINEN
The successful development of a material depends on reliable test methods to evaluate its suitability for the end use conditions. The use of existing thermo oxidative chlorine resistance method may serve as a tool for evaluating the variability of chlorine resistance on materials of the same type as long as no...
Author(s) : Paschal, Ciechanowski
Fittings used in water and gas piping systems are rarely, if ever, explicitly rated for load carrying capability relative to internal pressure. In some cases the material or resin used to manufacture the fitting is stress-rated to a period of 100,000 hours (PPI TR3) or 50 years (ISO TR 9080 and FDIS 9080). This...