Flange temp derating - CSA vs ASME
Flange temp derating - CSA vs ASME
(OP)
I had a discussion with a coworker about some piping and we disagreed. We have a crude pump station and the pump discharge piping is 600 ANSI rated and the pipeline is rated for 1440 psig. Our pump discharge PSV is set at 1440 psig. But we are running our crude at about 175F.
So derating the flanges we should have our set point at about 1395psi, should we not? My co-worker thinks there is something in CSA that states we are able to use the 1440psig because that is what the pipeline is rated for.
I didn't think there was a difference between CSA and ASME to determine derating for temperature for flanges?
So derating the flanges we should have our set point at about 1395psi, should we not? My co-worker thinks there is something in CSA that states we are able to use the 1440psig because that is what the pipeline is rated for.
I didn't think there was a difference between CSA and ASME to determine derating for temperature for flanges?





RE: Flange temp derating - CSA vs ASME
**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Flange temp derating - CSA vs ASME
If we were operating at 175F with 600 ANSI flanges on the discharge, wouldn't we need to design our piping / have our PSVs set at 1395 psig to protect our site piping?
RE: Flange temp derating - CSA vs ASME
Consider the more restrictive standard especially if ASME B16.5 is more conservative than some other reference. Also, verify that the connections exclude stainless steel or other alloys if you plan to operate toward the top of ASTM A 105.
RE: Flange temp derating - CSA vs ASME
RE: Flange temp derating - CSA vs ASME
I understand the weakest link is what you design for. That's interesting, because with all of our facility piping the flange rating (after temp derating)is always the weakest link (outside of some instrumentation).
RE: Flange temp derating - CSA vs ASME
**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Flange temp derating - CSA vs ASME
RE: Flange temp derating - CSA vs ASME
What the issue was with my co-worker is that he was talking about CSA certified flanges, not ASME certified. As per CSA Z245.12 Table 1 Note (2) "Pressure ratings are for temperatures lower than or equal to 120C"...and for PN 100 (Class 600) flanges the rating is 9930 psig.
So now we need to find out 2 things. What exactly the operating temperature is, and if the flanges used were CSA certified.
RE: Flange temp derating - CSA vs ASME
Also most pipeline grade materials are higher strength but thinner wal, to save on costs, hence why transition pieces are used when coming above ground.
My guess is you will have to set the PSV to 1395 and call it a lesson learned, but hey who knwos you might luck out.