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cement lined pipe

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PIPERAT

Petroleum
Feb 9, 2005
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we have a piping job that gets cement lined and and is graded to b31.3 standards. We x-ray the welds that are made before cement lining and do what repairs need to be done and then we send them to cement lining. The problem is that when we get the pipe back we still have a final butt weld to make and and apply expando to the joint "root bead" but by there specs you must butt-up the to bevels,buy doing so when you x-ray that final weld it has nonfusion all the way around so the xpando specs say to add an 1/8" to the cap to make up for the lack of fuision but b31.3 states that there must complete fusion. how would you grade this weld?
 
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This a case of do you follow the Code or the Spec? Specs' are usually used to add more or to specify detail where a Code may be vauge. In this caes you have the answer from ASME B31.3, though the spec sounds like it addresses the situation by saying it needs additional metal. You would not be able to claim that the piping had been welded to B31.3 if the welds are not repaired. YOu could however claim that the spec was met, though to be honest an additional 1/8" of metal on the cap does not sound to me like it would help. Excessive metal reinforcement does not add a signifigant amount of strenght infact it helps create a localized stress riser, this is an entirely seperate subject however.
 
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