I was recently reminded of how so many in process safety struggle to see their process(s) thru different lenses based on the piping’s life cycles. Using ASME B31.3 and 31.5, we see that these codes (e.g. RAGAGEPs) are design and build piping standards. Looking at API 570 series we see these are codes (RAGAGEPs) for the inspection of “in-Service” piping. Yes, both have pressure testing requirements for certain types of piping, but this pressure testing has its place based on the piping’s life cycle.
NEW piping for a PSM/RMP cover process has to be designed and built to a baseline RAGAGEP and in the USA our baseline RAGAGEP is the ASME B31 series, most notable being B31.3 for ordinary process piping and B31.5 for refrigeration processes. Both of these standards have their basic requirements, which includes welding requirements, inspection requirements and testing requirements that must be executed BEFORE the piping is put into service.
EXISTING piping (e.g. in-service) that is part of a PSM/RMP cover process has to be inspected per a chosen RAGAGEP and in the USA our piping baseline RAGAGEP is API 570 series. Some piping, most notably buried/underground piping has a requirement that it be “pressure tested” as part of its “in-service” inspection. And this pressure test is much different than the one we did we be erected the piping!
In B31 series our pressure test is only a 10-minute test, whereas the API 570 pressure test is an 8-hour test period. You may have the same immediate question as most… Why is ASME B31 test only 10-minutes and the API 570 test 8-hours? Two main drivers at play: