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Pressure Test of Relief Valve Body

01/25/2008 5:29 AM

Dear All

As you know the relief safety valves must be calibrated periodically according technical regulations and codes. For instance the popping value is the maximum operating pressure of protected vessel.

By the other hand the regulations are specifications to perform a pressure test of valve body. What does mean? Usually the inlet flange of relief valve body pressure rate is higher than outlet relief valve body. And the pressure test for valves must be conducted at a 1.5 time more than valve flange pressure rate. How to separate this different internal spaces of this type of valve? The internal mean spring, etc. must be removed from internal space. Please suggest any possibility or provide any link to find out more information about above matter.

Best Regards to All

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#1

Re: Pressure Test of Relief Valve Body

01/26/2008 1:28 AM

Hello Aurel Mares,

The safety relief valves can be calibrated by take it out of the system or vessel. And then install it to test pressure (usually water) equipment, increasing pressure to test value and you can calibrare your relief valve at this pressure.

But here I recommand that, you should take it to fully authorized place for "calibrating safety relief valve".

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#2
In reply to #1

Re: Pressure Test of Relief Valve Body

01/26/2008 1:48 AM

Do you know the way how to separate this different internal spaces of his mentioned type of valve????

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#7
In reply to #2

Re: Pressure Test of Relief Valve Body

01/27/2008 10:31 PM

I don't know realy why he want to test the body of safety valve. And I think that action is not need.

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Engineering Fields - Piping Design Engineering - New Member Egypt - Member - Member since 02/18/2007

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#8
In reply to #7

Re: Pressure Test of Relief Valve Body

01/28/2008 1:51 AM

Sometimes, it is necessary to to check the body of safety valve by hydrostatic or pneumatic test, especially after any repair, corrosion, and/or erosion of the body itself.

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Engineering Fields - Piping Design Engineering - New Member Egypt - Member - Member since 02/18/2007

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#3

Re: Pressure Test of Relief Valve Body

01/26/2008 4:18 AM

I'd like to distinguish between valve calibration and valve body test pressure.

Valve calibration means that the valve shall be periodically calibrated by hydrostatic test (may be by using test rig machine) to insure that it will work satisfactory at set pressure when such rising of pressure occurs. Set pressure may be 10-20% more than operating pressure, but in no case to exceed the design pressure of piping system, MAWP.

Where as Valve body test pressure, is a hydrostatic test pressure to the valve body to insure that its body with its flanges (if exist) will resist the pressure related to its class of rating. This test must be carried out at manufacturer's workshop in accordance with the related code of manufacturing. Please refer to the following API recommended practice and standards:

API RP520 Sizing, Selection and Installation of Pressure Relieving Devices in Refineries (Part I Sizing and Selection & Part II Installation).

API RP521 Guide for Pressure Relieving and Depressuring Systems.

API 526 Flanged Steel Pressure Relief Valves.

API 527 Seat Tightness of Pressure Relief Valves.

API RP576 Inspection of Pressure Relieving Devices.

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#4

Re: Pressure Test of Relief Valve Body

01/26/2008 6:04 PM

To hydro test both sides, you would need to gag the valve in the closed position. and test inlet side. No need to gag for testing the outlet "shell" side. I can help you with this, and also repairing and testing to NBIC and ASME codes. Contact 757-613-9213

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#5

Re: Pressure Test of Relief Valve Body

01/26/2008 6:06 PM

Here is a contact to help you. jkessinger@teamindustrialservices.com

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#6

Re: Pressure Test of Relief Valve Body

01/26/2008 8:04 PM

Why do you need to re-test the valve body? It was tested by the manufacturer, and unless you modified it-that still holds.

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#9

Re: Pressure Test of Relief Valve Body

01/28/2008 5:31 AM

Pressure test of valve body applies to testing of ball valve. Pressure relief valve is set to pop on certain pressure. If you vant to test ball valve, please confirm. I would tell you how to do it?

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#10
In reply to #9

Re: Pressure Test of Relief Valve Body

01/28/2008 6:20 AM

Dear Abdul Wasay

Thanks a lot fot your support in above matter solving. Are two different things:

- first, calibration the relief safety valve for the designed set point. Ussualy is done in work shop by the authorized inpsectors. This point is very clear.

- second, our regulations are specificated to perform a pressure test for normal valves body ( mean gate valve, globe valve, ball valve, etc. ) after work shop maintenance ( reparing, welding ). Same thing is required also for relief valve body. My question is how to conduct this pressure test if the inlet and outlet relief valve flanges have different pressure rate. How to split internal space of relief valve body?

Hope this help to cllarify the question

Best regards

Aurel

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#11
In reply to #10

Re: Pressure Test of Relief Valve Body

01/28/2008 7:49 AM

Please mention pressure ratings of inlet and outlet flange. Is it threaded at inlet and outlet?. For body testing you have to do overhualing of pressure relief valve to pull the spring out. Seal one end with threaded cap or blind flange with extension to install pressure guage. Use manual pump. Pressurise valve to the recommended press at open-air-drain end class that is it would be tested according to the lowes class flange/threaded end.

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#13
In reply to #10

Re: Pressure Test of Relief Valve Body

01/28/2008 10:51 PM

Dear Aurel Mares,

It is very easy, you just conduct the inlet and out let of safety relief valve and then perform hydro-pressure test.

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#14
In reply to #13

Re: Pressure Test of Relief Valve Body

01/29/2008 9:32 PM

performing hydro-pressure test is very easy, however the question here is How to split internal space of relief valve body? Do you understand the question?????

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#12

Re: Pressure Test of Relief Valve Body

01/28/2008 3:14 PM

I think what he is talking about is that allot of times the outlet flange will be a lower rating than the inlet flange. example 300 pd. flange on inlet and 150 pd. flange on outlet. if the valve was set to pop off at 160 lbs and he had a blind on the outlet then would he be over-pressuring this flange? I would like to mention that flange ratings are meant to be at certain temp. if you are using ambient temp. water then the 150 lb. side would be rated for more than 150 lbs. pressure. there are charts that show the pd rating as related to temp. on the net.

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#15
In reply to #12

Re: Pressure Test of Relief Valve Body

02/13/2008 3:49 PM

I don't have my ASTM books handy but if I remember correctly the YIELD strength of flanges and valve bodies is at least >4 X the maximum operating value. So you needn't worry about damaging the valve when testing for compliance within the specified operating pressures.

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Abdel Halim Galala (2); AbdulWasay (2); Anonymous Poster (4); AUREL MARES (1); Keith E Bowers (1); nam70 (3); pipewelder (1); taejonkwando (1)

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