While the hydrostatic proof test of control valves is well defined (e.g. ANSI/ISA-75.19) I have not been able to find a corresponding standard for burst testing. 
My research shows an "industry standard" of minimum 4-7 times the MAWP.  Is this accurate?  And what are the failure criteria?  Can we expect, for example, a 1" NPT threaded joint to withstand 2500 psig, and if not does a leaking thread constitute a burst failure for the  gate valve?
The ASME piping codes offer two options for establishing pressure rating.  1st is to comply with one of the listed standards such as ASME B16.34.  The second is to pressure test the product per section UG101 of the boiler and pressure vessel code.  UG101 lists several test methods that can be used.  Acceptance criteria depends upon the test technique.  Measured yielding of the body material, leaks, cracked coating, etc.  Per UG101, the minimum is 2.5 times the rated pressure (from P = 0.4 x H).

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