New Test Method for Evaluating the Oxidative Resistance of Polypropylene (PP) Piping Systems to Hot Chlorinated Water
1. Scope
1.1 This test method describes the general requirements for evaluating the long-term, chlorinated water, oxidative resistance of polypropylene (PP) piping produced in accordance with Specification F2389 used in hot- and cold-water distribution systems by exposure to hot, chlorinated water. This test method outlines the requirements of a pressurized flow-through test system, typical test pressures, test-fluid characteristics, failure type, and data analysis. NOTE 1Other known disinfecting systems (chlorine dioxide, ozone, and chloramines) are also used for protection of potable water. Free-chlorine is the most common disinfectant in use today. A PPI research project examined the relative aggressiveness of free chlorine and chloramines on PEX pipes, both at the same 4.0 ppm concentration and the same test temperatures. The results of the testing showed pipe failure times approximately 40 % longer when tested with chloramines compared to testing with free chlorine at the tested conditions. Based on these results, the data suggest that chloramines are less aggressive than free chlorine to PEX pipes. NOTE 2This test method is technically equivalent to Test Method F2023. 1.3 This test method is applicable to PP piping systems used for transport of potable water containing free-chlorine for disinfecting purposes. The oxidizing potential of the test-fluid specified in this test method exceeds that typically found in potable water systems across the United States. 1.4 Units--The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.5 The following precautionary caveat pertains only to the test method portion, Section 12, of this specification. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Keywords
polypropylene piping systems; PP; oxidative resistance; hot chlorinated water
Rationale
The current product standard refers to a test method used for PEX and PE-RT. Previous ballots resulted in negatives suggesting PP should have its own standard.
