[MW:3540] Re: 3534] RE: 3533] Re: 3531] Valve in hydrotest, is is allowed?

Valves have different leak classes. I think they go upto class V, with class V the most stringent. So even if the hydrotest is done, the valve may show some leak which could very well be within acceptable limits.

Regards

On Thu, Oct 22, 2009 at 3:05 AM, Kristian Lund Jepsen (KUJ) <KUJ@ramboll.com> wrote:

My experience with this problem is that the valve manufacturer need to be asked.

I recently had such a case, where the valve manufacturer accepted the test pressure, but the test-duration (30 minuttes for the piping in that case) could not be accepted by the valve manufacturer.

 

Therefore, in the end, we had to set a plug in the valve inlet, to avoid pressure testing against the valve closing mechanisms themselves.

 

regards

Kristian

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From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Rajneesh Gaur
Sent: 22. oktober 2009 08:28
To: materials-welding@googlegroups.com
Subject: [MW:3534] RE: 3533] Re: 3531] Valve in hydrotest, is is allowed?

Mr. Shashank,

I agree with Steven, but it's still a possibility if the client insists to do it. Although in normal cases we do not prefer to do it.

Secondly as far as rating is concerned if a valve is designed to withstand certain pressure, it is expected to withstand the without leaking in closed position.

As far as seat testing is concerned seat has to be tested from one/both sided at the manufacturer's facility either by pneumatic or hydro testing. This again depends on the type, size and rating of valves e.g. flow control valves can be tested from one side as per flow direction (marked on the valves).   

The decision I believe depends on of the criticality of the job, type of valve and its intended application and the most important the client's requirement.

 

Regards

Rajneesh

 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Steven Ko
Sent: Thursday, October 22, 2009 10:03 AM
To: materials-welding@googlegroups.com
Subject: [MW:3533] Re: 3531] Valve in hydrotest, is is allowed?

 

Hi Shashank,

 

All valves install in the system had a design pressure that can withstand the normal hydrotesting practise of 1.5 times of the operation pressure shall be acceptable without causing any damage to the valve. Full bore valve shall in the half open position to had the body tested as well during testing and the rest can be tested together in the system.

 

Closed valve in testing system used as isolator only tested one side of it and its not acceptable.

 

Seat testing of valves installed in the system pressure testing system its not appropriate as the flow of pressure need to determine which side to be tested and site testing its sometime hard to achieve this.

 

All seat testing normal tested by using low pressure air test on high pressure side and held for couple of minute, sometime its need to be tested on both ends depend on valve type. High pressure testing do employ but its depending on type of valves used and requirement..

On Thu, Oct 22, 2009 at 12:38 PM, Rajneesh Gaur <rajneeshgaur@gmail.com> wrote:

Mr. Shashank,

It will depend of the client requirements, and rating of the valve under consideration.

If the client asks for it to be done, it can be done provided the valve rating permits.

It would further prove the leak tightness of the valve or the quality of valve along with the line.

I have witnessed such hydro test.

 

Regards

Rajneesh

 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Shashank Vagal
Sent: Thursday, October 22, 2009 5:59 AM
To: materials-welding@googlegroups.com
Subject: [MW:3531] Valve in hydrotest, is is allowed?

 

Hi, Is it advisable to pressure test a water line for up to 10 bars with a valve already installed. (the valve will not be spaded during the test, it will only be in closed position)   Regards, Shashank Vagal

 

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Thanks you,

Best regards,
Steven Ko

email add:steven_ko@yahoo.com / stevenkmko@gmail.com

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