46 CFR 56.97-35 - Pneumatic tests (replaces 137.5).
(a) General Requirements. When a pneumatic test is performed, it must be conducted in accordance with the requirements of this section.
(b) Test medium and test temperature.
(1) The gas used as the test medium must not be flammable.
(2) The temperature of the test medium will be that of the available source unless otherwise approved by the Commandant upon review of the metallurgical aspects of the piping materials with respect to its brittle fracture properties.
(c) Check of test equipment before applying pressure. The test equipment must be examined before pressure is applied to ensure that it is tight and that all items that should not be subjected to the test pressure have been disconnected or isolated by valves or other suitable means.
(d) Procedure for applying pressure. The pressure in the system must gradually be increased to not more than one-half of the test pressure, after which the pressure is increased in steps of approximately one-tenth of the test pressure until the required test pressure has been reached.
(e) Examination for leakage after application of pressure. Following the application of pressure for the time specified in § 56.97-35(h), examination for leakage in accordance with 56.97-30(d) must be conducted.
(f) Minimum required pneumatic test pressure. Except as provided in § 56.97-35(g) or § 56.97-40, the pneumatic test pressure may not be less than 1.20 nor more than 1.25 times the maximum allowable working pressure of the piping subassembly system.
(g) Maximum permissible pneumatic test pressure. When a system is tested pneumatically, the test pressure may not exceed the maximum test pressure of any component such as vessels, pumps or valves in the system.
(h) Pneumatic test pressure holding time. The pneumatic test pressure must be maintained for a minimum total time of 10 minutes and for such additional time as may be necessary to conduct the examination for leakage required in § 56.97-30(d).