AWS D1.5, not pipeline but maybe there's a related provision in D1.1, which I don't have access to right now:
6.26.5.2. Acceptance of welds in ... Grades ... 100-100W steels shall be based on NDT performed not less than 48 horus after completion of the welds.
12.16.4 (fracture control plan) gives minimum cooling times for UT, MT, VT:
fillet welds on Gr. 50 or less, 24 hours
fillet welds on > Gr. 50, 48 hours
groove welds <= Gr. 50, weld depth <= 2", 24 hours
groove welds <= Gr. 50, weld depth >2", 48 hours
groove welds > Gr. 50, weld depth <= 2", 48 hours
groove welds > Gr. 50, weld depth >2", 72 hours
Hg
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