In field applications full QA records of times, temperatures and pressures achieved for all joints should be recorded, and the locations of welds identified on as-constructed site plans.
The most reliable methods of weld evaluation are the destructive type.
Destructive test methods require tensile testing of welds and pipe in order to establish the strength of the weld as a percentage of pipe strength.
Flexural testing may also be required in order to evaluate the effect of any joint misalignment.
Hydrostatic pressure testing will not determine the strength of butt welds, due to the stress across the plane of the butt weld being only 50% of the hoop stress in the pipe section.