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ASME B31.3-2016 provided the owner approves and the vessel test pres- 345.7.3 Examination for Leaks. The examination for sure is not less than 77% of the piping test pressure leaks required by para. 345.2.2(a) shall be conducted calculated in accordance with para. 345.4.2(b). while the system is at operating pressure. It is permissi- ble to omit examination for leaks of joints and connec- 345.5 Pneumatic Leak Test tions previously tested in accordance with this Code. 345.5.1 Precautions. Pneumatic testing involves the hazard of released energy stored in compressed gas. 345.8 Sensitive Leak Test Particular care must therefore be taken to minimize the The test shall be the Bubble Test — Direct Pressure chance of brittle failure during a pneumatic leak test. Technique in accordance with the BPV Code,Section V, Test temperature is important in this regard and must Article 10,Appendix I or another leak test method that be considered when the designer chooses the material has a demonstrated sensitivity not less than of construction. See para. 345.2.2(c) and Appendix F, 10-3 std ml/s under test conditions. paras. F323.4 and F345.5.1. When the Bubble Test — Direct Pressure Technique 345.5.2 Pressure Relief Device. A pressure relief is used device shall be provided, having a set pressure not (a) the test pressure shall be at least the lesser of higher than the test pressure plus the lesser of 345 kPa 105 kPa (15 psi) gage or 25% of the design pressure. (50 psi) or 10% of the test pressure. (b) the pressure shall be gradually increased until a gage pressure equal to the lesser of one-half the test 345.5.3 Test Fluid. The gas used as test fluid,if not pressure or 170 kPa (25 psi) is attained, at which time air, shall be nonflammable and nontoxic. a preliminary check shall be made. Then the pressure (16) 345.5.4 Test Pressure. The test pressure shall be shall be gradually increased in steps until the test pres- not less than 1.1 times the design pressure and shall not sure is reached,the pressure being held long enough at exceed the lesser of each step to equalize piping strains. (a) 1.33 times the design pressure (b) the pressure that would exceed 90%of the pressure 345.9 Alternative Leak Test described in para. 345.2.1(a) The following procedures and leak test method maybe 345.5.5 Procedure. The pressure shall be gradually used only under the conditions stated in para. 345.1(c). increased until a gage pressure that is the lesser of one- 345.9.1 Examination of Welds. Welds, including half the test pressure or 170 kPa (25 psi) is attained, at those used in the manufacture of welded pipe and fit- which time a preliminary check shall be made,including tings, that have not been subjected to hydrostatic or examination of joints in accordance with para.341.4.1(a). pneumatic leak tests in accordance with this Code,shall Thereafter,the pressure shall be gradually increased in be examined as follows: steps until the test pressure is reached,holding the pres- sure at each step long enough to equalize piping strains. (a) Circumferential, longitudinal, and spiral (helical seam) groove welds shall be 100% radiographed in The pressure shall then be reduced to the design pressure accordance with para. 344.5 or 100% ultrasonically before examining for leakage in accordance with para. 345.2.2(a). examined in accordance with para. 344.6. (b) All welds,including structural attachment welds, 345.6 Hydrostatic-Pneumatic Leak Test not covered in (a) above, shall be examined using the If a combination hydrostatic-pneumatic leak test is liquid penetrant method (para. 344.4) or, for magnetic used, the requirements of para. 345.5 shall be met,and materials, the magnetic particle method (para. 344.3). the pressure in the liquid filled part of the piping shall 345.9.2 Flexibility Analysis. A flexibility analysis not exceed the limits stated in para. 345.4.2. of the piping system shall have been made in accordance 345.7 Initial Service Leak Test with the requirements of para. 319.4.2 (b),if applicable, or (c) and (d). This test is applicable only to piping in Category D Fluid Service, at the owner's option. See para. 345.1(a). 345.9.3 Test Method. The system shall be subjected to a sensitive leak test in accordance with para. 345.8. 345.7.1 Test Fluid. The test fluid is the service fluid. 345.7.2 Procedure. During or prior to initial opera- tion, the pressure shall be gradually increased in steps 346 RECORDS until the operating pressure is reached,holding the pres- 346.2 Responsibility sure at each step long enough to equalize piping strains. A preliminary check shall be made as described in It is the responsibility of the piping designer,the manu- para. 345.5.5 if the service fluid is a gas or vapor. facturer,the fabricator,and the erector,as applicable,to