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ASME B31.3-2016 <br /> (b) present the danger of brittle fracture due to 100% ultrasonic examination in accordance with <br /> low metal temperature during the test para. 344.6. <br /> (d) Unless specified in the engineering design, lines (d) Instrument Connections. Threaded joints, tubing <br /> open to the atmosphere,such as vents or drains down- joints, or a combination of these joints used to connect <br /> stream of the last shutoff valve,need not be leak tested. instruments to previously leak tested piping need not <br /> be leak tested in accordance with para. 345.1. <br /> 345.2 General Requirements for Leak Tests (e) See also Appendix F,para. F345.2.3. <br /> Requirements in para. 345.2 apply to more than one 345.2.4 Externally Pressured Piping (16) <br /> type of leak test. <br /> (a) Except as provided in (b) below, piping systems <br /> (16) 345.2.1 Limitations on Pressure subject to external pressure shall be tested at an internal <br /> (a) Reduced Test Pressure. If the test pressure would gage pressure 1.5 times the external differential pressure, <br /> produce a circumferential or longitudinal stress (based but not less than 105 kPa (15 psi). <br /> on minimum pipe wall thickness) in excess of yield (b) As an alternative to leak testing under internal <br /> strength at test temperature or is greater than 1.5 times pressure, piping systems designed for vacuum service <br /> the component rating at test temperature,the test pres- only may be subjected to a vacuum leak test method, <br /> sure may be reduced to the maximum pressure that will technique, and acceptance criteria specified by the <br /> not exceed the lesser of the yield strength or 1.5 times owner.The vacuum leak test shall be performed follow- <br /> a component rating at test temperature. [See ing a written procedure complying with the applicable <br /> paras.302.3.2(e)and(f).]For metallic bellows expansion technical requirements of the BPV Code, Section V, <br /> joints, see Appendix X,para. X302.2.3(a). Article 10.Leak-testing personnel shall be qualified and <br /> (b) Test Fluid Expansion. If a pressure test is to be certified as required by Section V, Article 1, T-120(e) <br /> maintained for a period of time and the test fluid in the or (f). <br /> system is subject to thermal expansion,precautions shall 345.2.5 Jacketed Piping <br /> be taken to avoid excessive pressure. <br /> (c) Preliminary Pneumatic Test. A preliminary test (a) The internal line shall be leak tested on the basis <br /> using air at no more than 170 kPa(25 psi)gage pressure of the internal or external design pressure, whichever <br /> may be made prior to hydrostatic testing to locate is critical. This test must be performed before the jacket <br /> major leaks. is completed if it is necessary to provide visual access <br /> to joints of the internal line as required by para. 345.3.1. <br /> 345.2.2 Other Test Requirements (b) The jacket shall be leak tested in accordance with <br /> (a) Examination for Leaks. The leak test pressure shall para. 345.1 on the basis of the jacket design pressure <br /> be maintained for at least 10 min and then all joints unless otherwise specified in the engineering design. <br /> and connections shall be examined for leaks. The test <br /> pressure may be reduced to not less than the design 345.2.E Repairs or Additions After Leak Testing. If <br /> repairs or additions are made following the leak test,the <br /> pressure while performing this examination. <br /> (b) Heat Treatment. Leak tests shall be conducted after affected piping shall be retested, except that for minor <br /> any heat treatment has been completed. repairs or additions the owner may waive retest require- <br /> (c) Low Test Temperature. The possibility of brittle frac- ments <br /> when precautionary measures are taken to assure <br /> noun <br /> ture shall be considered when conducting leak tests at sound construction. <br /> metal temperatures near the ductile-brittle transition 345.2.7 Test Records. Records shall be made of each <br /> temperature. piping system during the testing,including <br /> (16) 345.2.3 Special Provisions for Testing (a) date of test <br /> (a) Piping Components and Subassemblies. Piping com- (b) identification of piping system tested <br /> ponents and subassemblies may be tested either sepa- (c) test fluid <br /> rately or as assembled piping. (d) test pressure <br /> (b) Flanged Joints. Flanged joints used to connect pip- (e) certification of results by examiner <br /> ing components and subassemblies that have previously These records need not be retained after completion <br /> been tested,and flanged joints at which a blank or blind of the test if a certification by the Inspector that the <br /> is used to isolate equipment or other piping during a test, piping has satisfactorily passed pressure testing as <br /> need not be leak tested in accordance with para. 345.1. required by this Code is retained. <br /> (c) Closure Welds. The final weld connecting piping 345.3 Preparation for Leak Test <br /> systems or components that have been successfully <br /> tested in accordance with para. 345 need not be leak 345.3.1 Joints Exposed (16) <br /> tested provided the weld is examined in-process in (a) Except as provided in (b) and (c)below,all joints, <br /> accordance with para.344.7 and passes with 100%radio- welds (including structural attachment welds to pres- <br /> graphic examination in accordance with para. 344.5 or sure-containing components), and bonds shall be left <br />