Use of API 510 and API 579 to Supersede UG-45

[spayette]

An existing, in-service vessel was originally constructed and stamped to ASME Section VIII, Division 1. Various nozzles do not meet the UG-45 requirements in effect at time of fabrication nor the same requirements which are currently in Table UG-45. The vessel now falls under the jurisdiction of API 510, which states that most of the technical requirements of the ASME Code can be applied to existing vessels.

Under the auspices of API 510 is it permissible to supersede the requirements of Table UG-45 using API 579/ASME FFS-1, Fitness for Service, and ultimately finite element analysis? Stated another way, is it permissible to supersede Table UG-45 by FEA for a vessel operated, inspected, and, maintained under API 510?

 

[LSThill]

spayette (Mechanical)


Subject: ASME FFS-1

see ASME FITNESS FOR SERVICES API 579-1/ASME-FFS-1 2007; API 579-2/ASME-FFS-2

2009

http://dl.ebmcdn.net/asme/flash/CS/ASME-FFS_6-09_v3.swf

example 1 slide: 25, 26, 27, 28,
31, 32, 33, 34, 35, 36

 

[spayette]

LSThill, Thanks for your reply. I viewed the presentation but it did not answer my previous question. I should explain too that my question was asked in the context of not using FFS to keep the equipment operating until it can be repaired, but rather using it to supersede Code of Construction requirements and allow the equipment to operate indefinitely at a lower thickness than what the original code would allow.

 

[spayette]

To add one other comment: When I referred to "thickness" I meant the overall thickness of a component, not the local thickness in a confined area such as due to a corrosion lake or pitting.