ASTM D572 (aging degradation in oxygen) currently states the following: 5.1.8 No copper or brass parts shall be exposed to the atmosphere, nor used in the pressure chamber and tubing or valves leading to it NOTE 3 Caution: For the evaluation of rubber compounds intended for service at elevated temperatures, the above test methods may be used with an operating temperature of 80 6 1C (176 6 1.8F), employing time intervals as suggested in 10.4, or as otherwise agreed upon. It should be noted that by increasing the aging temperature to 80C (176F) from 70C (158F) the rate of oxidation may be expected to be approximately double, and if the rubber compound property change may be expected to be approximately double, and if the rubber compound is of a rapid aging type, or if it is contaminated with such materials as copper or manganese, the rate of oxidation may be catalyzed to such extent as to become violent. It is presently unknown if there are reports or literature providing a rationale for the above statements. Similar statement may also exist in ASTM D573 (aging degradation in air). Stephanie Divens (D11.15 S/C on Degradation Testing chairperson) addressed this in new business at the June 2021 meeting, which led to the opening of this work item. It appears the 5.1.8 is more of a safety notation and should be considered being moved from 5.1.8 as written to a NOTE with the safety precautions. Other changes incorporated in G114-21 may also need to be reflected in D572 to ensure Committee D11/G04 consistency of practice. For example, all metals in contact with oxygen in the main flow stream should be of appropriate materials suitable for the given oxygen service, per G04 best practice. In general, diaphragm casings, diaphragm plates, springs, and other parts not in the main flow stream may be of ordinary materials such as carbon steel, stainless steel, or cast iron. It is suggested, however, that all valve body and trim parts in contact with the flow stream be made of copper, copper alloy, or nickel copper alloys.
Developed by Subcommittee: D11.15
Staff Manager: Melissa Marcinowski
Date Initiated: 05-21-2021
Technical Contact: Jess Waller
Ballot: D11 (22-01)
Status: Negative Votes Need Resolution