When valves are pressure tested by the manufacturer, they're pretty much just testing the body of the valve, with the valve open. They may do a leak test on the valve seats up to the rated pressure of the valve, but not up to hydrotest pressure.
It's advisable to use screwed plugs, blind flanges, or weld caps where you can. I would even go as far as to say that you can remove valves from the test section and replace them after the test.
Dor,
I am guessing you want to basically close the valve and pressure up against it to preform your test?
Certain types of valves, soft seated ball valves in particular, could be damaged by doing this.
Using a blind flange or some other expendable "plug" is the safest course of action. If that is just not an option, contact the valve manufacturer, and find out if their valve's seating/sealing mechanisim will handle the test pressure required. For certain types of valves, like certain plug valves, or metal seated valves, it may not really be a problem.
You should also take into consideration that the manufacturer will very likely void the warranty if your test pressure is above 1.1 times the valve's room temp MOP. So if you do damage the valve, you may very likely be replacing it out of pocket.
Best Regards,
VRF
That's right,I'm testing against the closed valve. In this case the valve is the limit between two different piping classes. The valve is on the CL 300 side, the test system on the CL 150. The test pressure is lower than the CL 150 flange rating so given the difference between the two classes ratings I think the closed valves will be able to pass the test. I'm not sure for how long the test pressure could be maintained.
Where can I get the MAWP of the valve from?
Thank you very much, your answers are very helpful.
1- Purpose of using Gate Valve on stream
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Gate Valve is used to open and close the flow only. Not commonly used in flow control with the following components.
2- Operation (open-closed) of Gate Valve
3- The Hydrostatic Test for Gate Valve requires 3 parts, Shell, Seat, and Backseat
The hydro-testing according to API 598. The valve standard is ASME B16.34
***Gate Valve – Hydrotest Backseat;
If you are looking for more details, kindly visit gate valve tester.
The Hydrostatic Backseat Test must be tested at a pressure of not less than 1.1 times the Maximum Operating Pressure by fully opening the valve and releasing the gland of the gate valve to check for leaks through the Backseat.
***Gate Valve – Hydrotest Shell;
Hydrostatic Shell Test must be tested at a pressure not less than 1.5 times the Maximum Operating Pressure by opening the valve partially open and tightening the gland to get the pressure. Then check for leaks through Shell.
***Gate Valve – Hydrotest Seat;
Hydrostatic Closure Test or Seat Test, continue to test from Shell Test at the pressure not less than 1.1 times of Maximum Operating Pressure by closing the valve fully closed and then checking the leak through Seat and Disk. Both tests must be done on two (2) – Side of Gate Valve.
***Valve – Pressure Test Duration;
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