Temporary Repairs on Piping

[rtsd]

As per API-570, metallic welded sleeve on pipe at low thickness locations is considered as Temporary Repair. What is the engineering reason behind due to which this type of repair can't perform like the original pipe , while the sleeve thickness and fillet weld sizes are calculated as per ASME PCC-2.

 

[MATEGRITY2009]

My opinion,

It might not directly related to engineering reason,
1. I think API intention to classified any repair that does not remove the defect as a "Temporary repair" because of the DEFECT still existing on piping or pressure equipment not completely remove from the equipment like a Permanent repair.

2. Temporary repair might be restore sufficient integrity to continue safe operation but might not 100% integrity like a Permanent repair.

finally, 8.1.4.1 allow to remain Tempo repair in place for a longer period of time only if approved and documented by the piping engineer.