ASTM E2930-13 (R2021) pdf free download.Standard Practice for Pressure Decay Leak Test Method.
1 .1 This practice describes a method for determining the leakage rate of a vessel subject to a positive pressure difference. The technique is based upon evaluation of the change of mass within the test object based on a pressure decay measurement. The pressure decay measurement uses the ideal gas equation of state and the measured pressures. temperatures. and time to determine the mass loss from the vessel. This method does not apply to deformable vessels.
5. Significance and Use
5.1 The equipment. test duration, and technique should be determined before commencement of the test based on the required test sensitivity or accuracy (see Annex A 1 and Annex A2). If the test is used to certify that the vessel has a minimum specified leakage rate, then the test equipment and test duration should be chosen to have a resolution ten times less than the specification and an accuracy which is four times less than the specification. The test should be designed so that the total pressure change is less than 10 % of the starting pressure. Leak test specifications should specify the vessel test pressure or differential pressure. If the test specification does not specify a test pressure. then a safe test pressure should be used that complies with the applicable safety standards.
6. Basis of Application
6.1 The following items are subject to contractual agreement between parties using or referencing this practice.
6.2 Personnel Qualification:
6.2.1 If specified in the contractual agreement. personnel performing examinations to this practice shall he qualified in accordance with a national or internationally recognized NDT personnel qualification practice or standard such as ANSI! ASNT-CP-189, SNT-TC-IA, NAS-410, or a similar document and certified by the employer or certifying agency. as applicable. The practice or standard used and its applicable revision shall be identified in the contractual agreement between the using parties.
6.3 Qualification of Nondestructive Agencies—If specified in the contractual agreement, NDT agencies shall be qualified and evaluated as described in Practice 11543. The applicable revision of Practice E543 shall be in the contractual agreement.
7. Interferences
7.1 Interferences in the reported leak values could result from desorption of gases from the vessel or adsorption of gases into the vessel. In addition, the effect of permeation of gases out of the test vessel may be significant for very low leak rate measurements. Eq A2.3 of Annex A2 can be modified to incorporate these additional effects if appropriate. This test assumes a nominal isothermal testing environment.ASTM E2930 pdf download.