Effect of Sudden Pressure on Piping System
Effect of Sudden Pressure on Piping System
(OP)
Dear all,
Just want to discuss. Is there any effect of sudden pressure on Piping system?
We did hydrotest for piping yesterday. Based on procedure, hydrotest shall be done in several stages. 25%, 50%, 75%, finally 100% MAWP. But unfortunately, we had problem with the system and it was difficult to manage the pressure. Eventually, hydrotest was done from 0% and suddenly pressed up to 100%. We are worried if this testing will give bad effect for the future. Need info plz. Thank you.
Just want to discuss. Is there any effect of sudden pressure on Piping system?
We did hydrotest for piping yesterday. Based on procedure, hydrotest shall be done in several stages. 25%, 50%, 75%, finally 100% MAWP. But unfortunately, we had problem with the system and it was difficult to manage the pressure. Eventually, hydrotest was done from 0% and suddenly pressed up to 100%. We are worried if this testing will give bad effect for the future. Need info plz. Thank you.





RE: Effect of Sudden Pressure on Piping System
The pressure rise as stated is usually just that you can find and correct leaks before they become a torrent or high pressure jet, but also allows the pipework to "shakedown" and adjust to internal pressure for the first time in its life.
That's my thoughts...
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RE: Effect of Sudden Pressure on Piping System
Thank you for your opinion.
So that condition will be vulnerable to the pipe?
Do you think that this phenomenon is just happened like water hammer?
And, could you tell me, is there any standard or code that regulate how much pressure increment rate allowed?
Thank you very much for your kind assistance
RE: Effect of Sudden Pressure on Piping System
There are recommended guidlelines for a gradual increase in pressure ....
I would perform a detailed walk-down/evaluation of the system and document the evaluation. Evaluate and measure any gross deformation of the system.
MJCronin
Sr. Process Engineer
RE: Effect of Sudden Pressure on Piping System
Other than mechanical damage caused by a sudden movement, yes, the issue is basically surge or shock loading. However you haven't answered the question of how fast this test pressure was applied.
You shouldn't exceed the test pressure.
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RE: Effect of Sudden Pressure on Piping System
I have reviewed ASME also. But From ASME, its just noted that "The pressure shall be applied by raising gradually to hydrotest pressure specified". They are not mentioned about how much exactly the pressure rate are.
@LittleInch, I have reviewed the chart and the pressure was applied from 0-100% of MAWP within 1-2 minutes.
Yes it shouldn't but I dont know exactly how much the allowable rate is.
RE: Effect of Sudden Pressure on Piping System
Not good practice, but the pressure rise thing is not a technically defined item so you won't find in a design code a time period.
Therefore there is no such thing as an "allowable rate" specified in a design code (AFAIK), only recommendations and guidance as to good practice.
This should be in the construction spec or testing spec issued by the design company.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Effect of Sudden Pressure on Piping System
I hope following the best practice is okay as long as there's no probs for our piping system.
Thank you very much for your kindly advice guys.
RE: Effect of Sudden Pressure on Piping System
Ganga D. Deka, P. Eng
Canada
RE: Effect of Sudden Pressure on Piping System
Are we 100% sure through master pressure guage& pressure checked and/or recorded at different points of "the piping segment under pressure test" as regards sudden pressure shoot up from 0 to 100%?
Was this a pressurizing with high pressure rotary or positive displacement piston etc.type pumps?
If all this is true and a confirmed high pressure 'sudden surge' took place like a water hammer that the whole "segment in question" needs to be thoroughly checked for deformities, dislocations or any other superficial/visible damage needing repairs/reinforcement prior to be in service
Best Regards
Qalander(Chem)
RE: Effect of Sudden Pressure on Piping System
RE: Effect of Sudden Pressure on Piping System
You keep mentioning "MAWP". This is more commonly used in pressure vessels and flange rating, but pipe systems usually use the terms MOP or MAOP.
In either case, neither of these are the hydrostatic test pressure which is considerably above the MAWP.
What is actually going on here?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.