Does your facility require a “leak test” of piping/equipment that is opened for maintenance BEFORE it is returned to service? Historically, the code allowed previously leak-tested flanged joints, instrument threaded joints, and tubing joints to be pulled apart and reassembled without a re-test. The updated provisions significantly expanded this. The code now broadly permits all mechanical joints that have been successfully leak-tested to be taken apart and reassembled (e.g., for maintenance, alignment adjustments, or equipment changeouts) WITHOUT requiring an additional pressure or leak test, provided strict joint assembly controls and proper bolt-up procedures are followed. But does this apply to a PSM/RMP covered process?
Granted, ASME B31.3 is our piping RAGAGEP, and the code now allows piping/equipment openings for maintenance, alignment adjustments, or equipment changeouts WITHOUT requiring an additional pressure OR leak test, provided strict joint assembly controls and proper bolt-up procedures are followed. This may be acceptable for ordinary chemical piping; however, PSM/RMP-covered piping may need extra care.
We must understand that ASME B31.3 applies to ALL chemical piping, based on IFC Chapter 50, Hazardous Materials. The vast majority of this hazardous materials piping is NOT associated with a PSM/RMP covered process or even many of the PSM HHCs and RMP EHSs. But in my professional opinion, it just does not make risk sense to close up a PSM/RMP-covered process and NOT do a “leak test” on that flange. I frown on facilities doing a “pressure test” on piping that has already been pressure tested, but I always encourage and TRAIN my clients to do a “leak test” BEFORE returning the process to service.
Some of my biggest incidents have come from a flange leaking during the “return to service” phase; hence, almost every company I worked for required this as general practice on ALL HAZMAT piping, regardless of PSM/RMP coverage. But I guess times have changed, and now our beloved ASME B31.3 no longer requires it.
345.2.3 Special Provisions for Testing
(a) Piping Components and Subassemblies.
Piping components and subassemblies may be tested either separately or as assembled piping.
(b) Flanged joints.
Flanged joints used to connect piping components and subassemblies that have previously been tested, and flanged joints at which a blank or blind is used to isolate equipment or other piping during a test, need not be leak tested in accordance with para. 345.1.