Hydrotest or Pneumatic test?
Hydrotest or Pneumatic test?
(OP)
We have a problem in pipe pressure testing,
We are able to conduct the pipeline pressure test using air instead of water to the same requirements as expressed in desired standard in certain condition. But my question is, would we need to modify the line parts or consider any thing for this change or would we have any constrain on line length in new test procedure?
We are able to conduct the pipeline pressure test using air instead of water to the same requirements as expressed in desired standard in certain condition. But my question is, would we need to modify the line parts or consider any thing for this change or would we have any constrain on line length in new test procedure?





RE: Hydrotest or Pneumatic test?
Without more details, no comment on the rest.
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"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: Hydrotest or Pneumatic test?
You might want to read this thread: thread378-238325: Why NOT to pneumatic test
Patricia Lougheed
Please see FAQ731-376: Eng-Tips.com Forum Policies: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.
RE: Hydrotest or Pneumatic test?
GOOGLE "pneumatic test" and disaster or accident or explosion......What fun..!!
http://www.absa.ca/newsletter/v07-2002/v7-iss2.pdf
http://www.eng-tips.com/viewthread.cfm?qid=176703
h
Annnd........ best of all.......that famous flying tank in Brazil !!!
( Case #8)
http://www.psig.sg/Don/Case%20Studies%202006.pdf
Comments ??
-MJC
RE: Hydrotest or Pneumatic test?
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"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: Hydrotest or Pneumatic test?
Bottom line of all of them is that there are a BUNCH of people who feel that doing a static strength test with a gas is irresponsible and fairly evil. There are some people who feel that pneumatic tests can be done safely and are allowed by the code.
My argument is always that the Engineer designing the test is obligated to actually design the test and determine where stresses will be maximum and what that max value will be. Also what is the minimum ambient temperature that is acceptable to start/perform/complete the test. If you do your sums, there are many times that a pneumatic test can be done much more safely than a hydrostatic test (think Rocky Mountains, pressure at the top of a hill vs. pressure at the bottom).
David
RE: Hydrotest or Pneumatic test?
"The best laid schemes o' mice an' men / Gang aft a-gley." [often translated to the effect, "The best-laid plans of mice and men/often go awry," (in Robert Burns 1785 poem, "To A Mouse, on Turning Her Up in Her Nest, With The Plough")]
While proponents of the pneumatic testing practice (and maybe even some when there might be other alternatives conceivable to skilled engineers, at least if considered far enough upfront) might argue the "often" wording, it appears that now 224 years later this is perhaps no less true. I believe what can go "awry" or wrong is in reality limited only by the frailies and imagination of Man, and what designs and products etc. he hath wrought.
One thing is for sure, WHEN things go wrong for any reason in at least high pressure pneumatic testing of large diameter tanks and piping, there can be hell to pay!
RE: Hydrotest or Pneumatic test?
My collegues that use hydro, it takes 3 times as long to start up, it costs more, and when something goes wrong, it takes days to fix.
RE: Hydrotest or Pneumatic test?
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"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: Hydrotest or Pneumatic test?
You just about have to think that someone involved in each of these unfortunate incidents (and many more I have heard of involving pneumatic testing in many years) THOUGHT what they were doing would work (in addition to the obvious of being cheaper and expedient, and requiring maybe thinner or less reinforced pipes/supports). Unfortunately, it appears "stuff" (of all sorts) nevertheless "happens" in some pneumatic testing that may not have exhibited that level of violence had appropriate filling and hydrostatic testing been conducted.
My condolences to the victims and their families etc. Have a good weekend.
RE: Hydrotest or Pneumatic test?
RE: Hydrotest or Pneumatic test?
we tested with 1/4 psig just for leaks.
still had a top cone roof pop off once
pnuematic tests with large volumes, even at moderate pressures, scare the bejeezers out of me
RE: Hydrotest or Pneumatic test?
Edward L. Klein
Pipe Stress Engineer
Houston, Texas
"All the world is a Spring"
All opinions expressed here are my own and not my company's.
RE: Hydrotest or Pneumatic test?
RE: Hydrotest or Pneumatic test?