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Piping testing sequence ???

7 replies [Last post]
Nicolas Berger
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Hi all,

I’m a bit lost to link up the following activities :
3-Leak test

Thanks by advance to help me out
My view is 1-2-3.

Please give me yours and explain me what’s the real difference between Hydrotest & Leak test ?

Thanks by advance


Ali Alharthi
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in addition to the above, please note the following:


after finalizing the punching actvities and releasing the TPs for testing :Tp shall pass through three stages 



draining or drying


By passing the above stages the team will start working on the B punch points in order to releawe the TPs for reinstatement.

reinstatement stage is very criticial stage since it is opening the work fronts for the electric and instruction teams to start glanding the termination activities.


after the reinstatement stage , the commisioning team will start creating the ITRs for all systems in order to start the mechanical stage.



thank you, ali

Ali Alharthi
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with regards to your concerns, 

the sequesnse is correct and this sequense is mandatory since you have to drop a lot of items during hydrotest activities such as valves and some special items which may impacted negatively by the test medium.

before the hydrotest stage there is a stage which is very important called punching stage, this stage normlly will be conducted by the QC and third party inspector as a joint venture. Engineering will issue test packs for each system, during the walkdown all the punch points will be categorized as A or B or C , A means TP cannot be released for testing till closing this punch point, B means TP can be released for testing however TP cannot be offered for reinstatment till closing this punch point, C normally will be closed before submitting the dossioer for PRFCC "RELEASED FOR Comm. Certificate".

A punch points normally will be any hot work balance and direct to the pipe such as shoe supports ..etc.

B punch points such as valves to be reinstalled after hydrotest, removing the temporry items ..etc.

C punch points such as insualtion , paint toch up ..etc.


hydrotest stage is not easy stage , since TP shall pass three stages flushing,testing and drying or draining.


thank you


Ali waqas
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Plant Piping Questions:

1) Can anybody tell me Hydrotest contents(Hydrotest Flow chart) in sequence?

2) All processes done on pipes form material receiving to final installation?

3) Pre-Commossioning, Reinstatment ,Commossioning and MCC?

Pipeline Questions:

1) All processes done on pipelines from material receiving to final installation?


Thanks in Advance

volkan AKIN
User offline. Last seen 5 years 28 weeks ago. Offline
Joined: 23 Dec 2007
Posts: 9
Your sequence is absolutely right...
aim of this test is: testing pipes with pressurized water,
it doesnt matter if the pipe has shop weld or field weld.
also hydrotest has to be done, after all welds are completed
(support weld, pipe weld )..
required manhour for hydrotest is depends on:
a)test package
b)pipe size
c)pipe sketch
d)elevation of pipes
means: installing pipes as on drawings and removing test,
preparing the line for ready for turnover.
3-Leak test:
testing a whole system, in generally with air.
aim of leak test: monitoring leakages from flanges..
only pump entrances are blinded,
DIFFERENCE hydro and leak:
hydro:monitoring leak from welds
leak : monitoring leak from flanges

If also anybody has piping activity codes P3
I will be glad if you can sent it to
James Barnes
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true, except if the reinstallation of the piping requires a closing site weld, then the hydrotest may be carried out on the insitu installation. This would require blinding off of an area of piping including all new welds and joints. Depends on the system and your policies, but we H-test all welded connections. On site H-tests may encompass several piping scope items in a "cluster" however what this saves in blinding and testing MH can be questionable when measured against the confusion it can cause.

by Leak test, I would guess that you are referring to a system wide test, carried out at the end of the works on that airtest system. This, for us at least, involves putting the system under a small amount of air pressure to check for leaks at mechanical joints. As the pressure is low, the H-test is also required to ensure test pressures are achieved.
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Absolutely true!!!
David Sharp
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It looks like your planning a system installation ?

My experience is as follows:

Hydro test is simply an integrity test of the pipe spool for example, using water pressurised to "x" bar before it is then installed in the piping system(conforming to API requirements).

A leak test is carried out after the pipe has been "reinstated" in the system (ie mineral lube oil) to test for joint leaks at the flange/hardware connection during and pre commissioning activity and prior to handing back to operation.

I’m sure the piping experts will have more to offer on the specific’s but hope this helps for now.