Low temperature fittings, and /or pipe
Low temperature fittings, and /or pipe
(OP)
Hi,
We are revising our standard specifications for tanks and piping, etc. Our projects are located in Arctic and Sub-Arctic and the installations are outdoors.
Our current specs for tanks call for low-temp steel, of course, and we ask for low temp pipe flanges and valves.. but piping is currently only ASTM A53 Grade B piping and ASTM A234 Grade B fittings, because "of the low pressure and low stresses on the
piping and fittings" -how it was explained to me .. Although we have had no problems thus far, none of these installations to these specs are very old. It would make sense to me to have piping specced for low temps as well. Our consultant doing spec revisions suggests this strongly. Any thoughts please--my metallurgy is rusty!
We are revising our standard specifications for tanks and piping, etc. Our projects are located in Arctic and Sub-Arctic and the installations are outdoors.
Our current specs for tanks call for low-temp steel, of course, and we ask for low temp pipe flanges and valves.. but piping is currently only ASTM A53 Grade B piping and ASTM A234 Grade B fittings, because "of the low pressure and low stresses on the
piping and fittings" -how it was explained to me .. Although we have had no problems thus far, none of these installations to these specs are very old. It would make sense to me to have piping specced for low temps as well. Our consultant doing spec revisions suggests this strongly. Any thoughts please--my metallurgy is rusty!





RE: Low temperature fittings, and /or pipe
"Make everything as simple as possible, but not simpler." - Albert Einstein (1879-1955)
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RE: Low temperature fittings, and /or pipe
Daianto (Caluna)
RE: Low temperature fittings, and /or pipe
There are a lot of brittle failures for non-impact tested and non-killed steels in the low temperature environment (-40°F to 32°F). I think it is appropriate to use pipe for low temperature service in Arctic conditions. When I was doing gas work in northern Minnesota, we did use API 5L, but with extra V-notch toughness. I would imagine you're looking at temperatures near -40F or worse.
Is he recommending A334?
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RE: Low temperature fittings, and /or pipe
RE: Low temperature fittings, and /or pipe
Consultant recommends A333 grade 6.
RE: Low temperature fittings, and /or pipe
dcasto, your system gets cold when its being depressured, but this system is cold when it is being pressured, right?
"Make everything as simple as possible, but not simpler." - Albert Einstein (1879-1955)
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RE: Low temperature fittings, and /or pipe
(Some of our locations have temperatures below minus 46.)
RE: Low temperature fittings, and /or pipe
I wasn't thinking you have pressures < 25%.
"Make everything as simple as possible, but not simpler." - Albert Einstein (1879-1955)
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RE: Low temperature fittings, and /or pipe
I meant to say in that post that our spec (currently) does not ask for Charpy tests on the A 53 pipe, which it should as our conditions are outside those of the exclusion.
the A333 pipe is quite a bit more costly so management will need good justification....
I have heard of API 5L pipe-is it more commonly used in petroleum industry than others? Should we consider it- (with charpy testing)?
RE: Low temperature fittings, and /or pipe
B31.3 uses allowed stresses, B31.4 & 8 use specified minimum yield stresses with reduction factors to get the allowed stress and I think B31.3 does not recognize the higher yield stresses of 5L above the 30,000 psi of grade B. Double check that, as I have not looked at that particular clause in a few years, so I'm not sure how at how using 5L would be affected by that code difference.
"Make everything as simple as possible, but not simpler." - Albert Einstein (1879-1955)
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http://virtualpipeline.spaces.live.com/
RE: Low temperature fittings, and /or pipe
RE: Low temperature fittings, and /or pipe
"Make everything as simple as possible, but not simpler." - Albert Einstein (1879-1955)
***************
http://virtualpipeline.spaces.live.com/