How to calculate check valve test pressure, 1) Metal seat & non metal seat 2) High pressure &amp

[GAL02]

Good evening to everybody!
How to calculate check valve test pressure, for the following criteria
1) Metal seat & non metal seat
2) High pressure & low pressure.
As per Valve testing STD.API 598 finally it directs to ASME B16.34
which is not clear.
All of you are requested to elaborate the same.


With regards

 

[yousif aldossary]

good day dear
i dont know what version of API598 you were refering to but valves shell tests and other pressure test are clearly stated in section 3.7 table 2/3 , page 4

regards

 

[GAL02]

Dear sir, Good afternoon !
I am referring API 598 (Valve inspection & testing)
Pl. guide us.

With regards

 

[Ehzin]

Hmm.. so first Yousif's question is asking which year of API-598 although I don't know how much changes between them so I can't comment on that.

But here's some questions/comments.

1)

Assuming it's a B16.34 valve, what class rating is the valve are you looking at?​

2)

Low pressure is optional unless specified by purchaser.​

3)

Shell and high pressure closure tests are required.​

4)

Assuming class 150, 300, 600, 900, 1500 class flanged per B16.34 high pressure and shell test pressure is dependent on valve material. You'll need to refer to B16.34 for specifics unless you provide more details.​

5)

Info I could find from where I am seems to have low pressure closure around 60-100 psig although I'd recommend verifying that information. Seems odd.​

If you have access to API-598 it should be fairly straight forward. If you have specific questions about portions of B16.34 exactly what issue are you having?

Generally...
Shell test is performed at 1.5 times pressure rating at ambient based off the material and valve class.
High pressure seat is performed at 1.1 times pressure rating at ambient based off the material and valve class.
Allowed leakage rate during high pressure seat test is dependent on either being resilient (Non-metal) seat or metal seat. Resilient seats are allowed no leakage during test duration while metal seats are limited to 0.18 cubic inch per minute per inch of nominal pipe size.

Need to confirm these details with the standards as I don't have a real copy of either in front of me. If you have any more questions feel free to ask.

Thanks,
Ehzin

 

[GAL02]

Dear Mr. Ehzin, good morning & thanks for your elaborated reply.
We have following valve details which we need to test (Shell Test & HP Closure Test)
Data:
Equipment: Synthesis Gas Compressor inlet line
Service: Synthesis Gas
Valve: Swing check
Class: 2500 #
Connection : Flanged (RTJ)
Body: A216 WCB
Trim : A182 F6 (Metal seat)
Operating Temp.: 190°C, Tmax.: 360°C
Operating Pres.: 266 Kg/cm2, Pmax.: 295 kg/cm2

I thing above data is sufficient & awaiting for reply.


With regards

 

[GAL02]

Pl. find herewith ASME B16:34 statement, not clear to me.

 

[Ehzin]

Alright, that's a good bit of info. Essentially, there's a table 2-1.1 in ASME B16.34 titled ratings for Group 1.1 Materials. One of the materials that falls under Group 1.1 is A216 Gr. WCB. At ambient temperatures the pressure rating for a class 2500 B16.34 flange valve is 425.5 bar. This leads to a shell test of 639 bar ( 1.5 times 425.5 rounded up ) and a high pressure closure test of 469 bar ( 1.1 times 425.5 rounded up ). Also this is assuming hydrotest.

Now I would recommend looking into the vendor's documentation on this. If they're not specifically marked as B16.34 then technically they're not required to meet the above testing requirements. There's much more details than just test pressures that should be understood before these valves are brought up to these pressures. If you have any more questions just let us know.

Out of curiosity, are you the end user in this scenario or a testing/valve maintenance facility? I suppose it doesn't matter although if you're the end user you may be able to just discuss this with someone that is more familiar and could perform this testing along with any necessary repairs. Also as mentioned, determining the brand of valve and referring to their documentation may be beneficial. Some marking should be stamped directly on the body.

Thanks,
Ehzin

 

[GAL02]

Dear Mr. Ehzin, Good morning!
Thanks for your feedback, I am the end user of the valve.

With regards