B31.3 imposes the following requirements, which are only a few of the elements of a leak testing plan:
a) All joints, including welds and bonds, are to be left uninsulated and exposed for examination during leak testing, except that joints previously tested according to B31.3 may be insulated or covered. For sensitive leak tests, all joints shall be unprimed and unpainted [345.3.1].
b) Temporary supports may be necessary to accommodate the weight of the test fluid used for leak testing of vapor or gas lines [345.3.2].
c) Expansion joints represent a special testing situation. Refer to B31.3 for additional information [345.3.3, 345.4.2(c), Appendix X, Para. X3.2.3(a)].
d) At the limits of tested piping, equipment that is not included in the test shall be disconnected from the piping or isolated by blinds or other means. Valves may be used at the limits of tested piping, provided that the valve is suitable for the test pressure [345.3.4].
B31.3 makes the piping designer, manufacturer, fabricator, and erector responsible, as applicable, for preparing test records required by the Code and the engineering design [346.2]. Test records required by B31.3 include:
a) date of test [345.2.7(a)],
b) identification of piping system tested [345.2.7(b)],
c) test fluid [345.2.7(c)],
d) test pressure [345.2.7(d)],
e) certification of results by the examiner [345.2.7(e)],
f) examination procedures [346.3(a)], and
g) examination personnel qualifications [346.3(b)].
Items a) through e) need not be retained after completion of the test if the inspector certifies that the piping has satisfactorily passed a pressure test as required by the Code [345.2.7]. Items f) and g) shall be retained for at least 5 years after the record is generated for the project [346.3].