Plastic Pipes Conference Association # 2001 Munich
A 24 Design of Experiments (DOE) test grid was run to examine the influence of the following variables on the chlorine resistance of PEX pipe; temperature, water quality (pH, chlorine concentration, ORP) and metal ions (inert vs. copper fittings). The four factors were each run at two levels and a centre point was included. A minimum of two replicates was run for each condition. A total of fifty failure points was generated. The significant factors were temperature, pH, Fitting Type, and Chlorine level (marginal). The significant interactions were pH and Temperature, and Fitting Type and Temperature (marginal). At both the chlorine levels of 3 and 5 ppm, a shift in pH from 6.5 to 8.5 is predicted to result in approximately a threefold increase in the estimated test lifetime at 60°C.
Author(s) : Leevers, Henderson, Pereira
Laboratory-scale S4 tests have been used to determine whether it would be possible, at any realistic working pressure, for a loosely-fitted PE liner within a rigid host pipe to fail by Rapid Crack Propagation (RCP). The standard ISO 13477 S4 method was modified by replacement of the containment ring cage by a rigid,...