It is not a rule of thumb. It depends on the base metal, service condition (severity), defects’ type/direction/depth, welding processes, welding consumable material, etc.
Please find the followings.
API Standard 1104/510/570/580/598/653
API RP582/572/573/577/1107/934/2009/2201
API Publ.938/939-B
NACE Paper #00688
ASME Section VIII, Div.1, UW
ASME B31.3
API 650
Company Standards
Please find the followings.
API Standard 1104/510/570/580/598/653
API RP582/572/573/577/1107/934/2009/2201
API Publ.938/939-B
NACE Paper #00688
ASME Section VIII, Div.1, UW
ASME B31.3
API 650
Company Standards