【国外标准】 Standard Test Method for Evaluating the Oxidative Resistance of Multilayer Polyolefin Tubing to Hot Chlorinated Water (Withdrawn 2010)

Environment or oxidative time-to-zero OIT data derived from this test method, analyzed in accordance with Section 13, shall be suitable for extrapolation to typical end-use temperatures and time. The extrapolated value(s) provides a relative indication of the resistance of the tested multilayer tubing or system to the oxidative effects of hot, chlorinated water for conditions equivalent to those conditions under which the test data were obtained. The performance of a material or piping product under actual conditions of installation and use is dependent upon a number of factors including installation methods, use patterns, water quality, nature and magnitude of localized stresses, and other variables of an actual, operating hot-and-cold water distribution system that are not addressed in this test method. As such, the extrapolated values do not constitute a representation that a multilayer tube or system with a given extrapolated time-to-zero OIT value sahll perform for that period of time under actual use conditions.Note 3—the extrapolated value of the oxidative induction time-to-zero OIT data provides a conservative estimate of the life of the multi-layer tube.1.1 This test method describes the general requirements for evaluating the long-term, chlorinated water, oxidative resistance of multilayer tubing which includes an inner layer of a polyolefin material such as PE or PEX (for example, see Specification F 1986 or F 1281). This test method outlines the requirements of a pressurized flow-through test system, test pressure, test-fluid characteristics, failure type, and data analysis.Note 1—Other known disinfecting systems (chlorine dioxide, ozone, and chloramine) are currently used for protection of potable water; however, free-chlorine is the most common system in use today. Disinfecting systems other than chlorine have not been evaluated by this method.1.2 This test method is valid for polyolefin materials that are stabilized with hindered phenolic type anti-oxidants that shall be analyzed using the Oxidative Induction Time (OIT) method (for example, D 3895).1.3 Guidelines and requirements for test temperatures, test hoop stresses, and other test criteria shall be stablished by prior testing of multilayer tubing and solid-wall PEX and PE tubing. Other related system components that typically appear in a multilayer tubing hot-and-cold water distribution system shall be evaluated with the multilayer tubing. When testing multilayer tubing and fittings as a system, it is recommended that the anticipated end-use fitting type(s) and material(s) be included in the test circuit since it is known that some fitting types and materials can affect failure times. Specimens used shall be representative of the piping product(s) and material(s) under investigation.Note 2—The procedures described in this test method (with some modifications of test temperatures or stresses, or both) have been used to evaluate pipes manufactured from polybutylene (PB), polyethylene (PE), polypropylene (PP), cross-linked polyethylene (PEX), and multilayer (polymer-metal composite) pipes.1.4 This test method is applicable to multilayer tubing and 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.1.5 The values stated in cm-gram units are to be regarded as the standard. The values given in parentheses are for information purposes.1.6 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.