How do I deal with API equipment with flanges thinner than specified minimum?
API 6BX open face flanges all have raised faces while API 6B flanges may have raised faces omitted. All flanges included in API Spec 6A may have raised faces. With this understood, all flanges appearing in API Spec 6A that have had refacing bringing them to minimum thickness or less may have weld repair, building a raised face on the flange that may restore the flange to maximum thickness, so long as the thickness of the portion of the flange extending in diameter beyond the raised face designated dimension has a remaining thickness equal to the API specified minimum flange thickness, less the specified depth of the ring groove.
To minimize the necessity of refacing of flanges, many operators purchase equipment with Corrosion Resistant Ring Grooves (see: About SS and CRA Inlayed Ring Grooves).