Piping system Hydrotesting

[a5a33213]

ASME B31.3 lower Hydrotesting limits are 1.5 times design presure.Include SA 105 welneck flanges in the system to be tested then B 31.3 is not clear on the maximum test pressure limits.B 31.3 tables at ambient temp 100 deg F max
SA 106B(p1 Gr1 material) has 285 PSIG design pressure limits.Therefore min. test pressure is 427.5 PSIG.Often LDT tables directs testing at 450 PSIG.Factor Gage calibration deviation tolerances and max stress allowed for SA 105 flange then we have many flags been raised.
Question: What is the max hydrotest pressure allowed for this type of test? why? ASME should revisit this issue and include tolerance guide lines for inspectors such as myself.

 

[apiguy]

The flanges are subject a different hydro-pressures during the manufacturing stage as well as the pipe. Consult B16.5 for those pressures.

Typically, when performing a hydro in the field you will find that the fabricator will usually pressurize the system to 1.5 times the flange rating.

As an inspector, you should review what the design specification calls for and verify that the test was performed at the proper pressure. (and temperature for that matter!)

The APIGUY....