Hydrotest of multiple valve

[hhalim]

Hi,

Is there any restriction in hydrotesting of multiple valves connected in series to meet ASME B16.34. We have 200+ of globe valves to go for hydrotesting, to reduce the test lead time we are thinking of connecting 5 valves in series and test them at the same time using test pressure and duration required by ASME B16.34

Regards,
Habas

 

[TugboatEng]

This works if your valves reliably pass their hydrotest. If you test many on a manifold simultaneously and one fails then you'll have to retest every batch.

The key here is to find quick way to fixture the valve for testing.

 

[Danlap]

Hi,

From which stand point are you? manufacturer or site installation?
In short there is no restriction.
Hydrotest consist of two things closure and seat test.
Closure or body test is quite straight forward, 1.5xMAWP, for testing period given in API 598/ISO 5208/API 6D, if there is no leakage then it should be alright.
For seat test is a bit tricky, since you can only measure the leakage from the farthest end (outlet of your 5th valve). And if you find leakage on any valve then you have to drain all or add more water before testing the next one. In the end the result is quite vague since you don't know for sure which one is failing, takes time to stabilize pressure and takes time to add water and purge pressure.
Agree with TugboatEng, you may need to re-test the batch. Even manufacturer which can produce 100+ valves per day still do this one by one, with harmonious testing process. Such as quick clamping mechanism and more than sufficient amount of water readily available.
For this reason, under a very restricted amount of schedule or for some other reason, maximum so far I saw is three valves in series.

Regards,
MR

https://nosuchvalve.com

All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected

http://www.eng-tips.com/faqs.cfm?&rat1=2&fid=376

 

[0707]

In my opinion I think you can do it.

luis

 

[HitokiriAoshi]

No restriction. I would only do it to test for external leakage using this technique. This technique is only useful if you require very high holding time, more than the time require to bolt the valves together.

i've never hear of a job site trying to test 200+ globe valves at once, so I think this is a supplier/manufacture case. I wouldn't do it, use a test stand.

Luke | Valve Hax

 

[hhalim]

All, thank you for the valuable inputs. We are the site installer. We want to make sure all the valves are OK prior to installation into the pipelines.

Danlap, I am referring to shell hydrotest and not the seat test.

I read through ASME B16.34, API 598 & EN12266 and couldn't find any restriction.


API598 and I quote "Except as provided in 6.2.2, the shell test shall be made by applying the pressure inside the assembled valve with
the valve ends closed, the valve partially open, and any packing gland tight enough to maintain the test pressure,
thereby,

En12266 "The end connections of the shell shall be blanked off and all cavities filled with the test fluid"

So, as long as the first end of the valve & the last end of the valve in series connection is closed during the duration of the test, I should be OK.

But I agree, the tricky part will be , if 1 unit fail from 1 series and I have to test the rerest of the valve.

Habas

 

[Danlap]

Hi Habas,

Yes, it is a common practice to (shell) hydrotest the piping with multiple valves (even more than 5) at 1.5 MAWP. Especially when (new) welding connections are presence.
Good that you quote API598, my advise is not to loosen the gland packing. Just keep it as is, and open the valve.

Success with the hydrotest.
Regards,
MR

https://nosuchvalve.com

All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected

http://www.eng-tips.com/faqs.cfm?&rat1=2&fid=376

 

[HitokiriAoshi]

Unless this is a crappy manufacture, or you are welding the valve in, my recommendation is to just test it with your system. the valve have already been tested once at the manufacturer, and the chance of it leaking externally after that is very very low, think 1 out of 1,000. making the effort of test before installation very little.

some cases would change that odd.

1) temperature difference, or soft seal failing due to installation, think ball valves which relies on o-ring for primary seals, failing due to too cold or too hot temperature once in line. ( you have globe valve, this does not apply)
2) blast beads destroying stem seals

In fact, if you want to do pre installation check, my recommendation is to fully stroke the valve open, inspect the stem on the globe valve for damage and external debris in packing gland area, inspect gland torque, and return to original position, as well as double check raise face or other facing condition (follow 16.5 imperfection guideline). this activity will worth the cost and effort.

Luke | Valve Hax |

https://valvehax.com/

 

[bcd]

I advise against testing the valves at site. Testing by those not familiar with details of testing valves, and using equipment that may not be suited to testing valves easily leads to damage and voiding of the warranty.

If I was a manufacturer, and someone from a site called me and said a valve was leaking or damaged, and that they had pressure tested the valves, the conversation will quickly change to how the valves were tested and how much the site installer is going to pay to get the valves fixed.

If you are going to do this regardless of this advice, and the advice from HitokiriAoshi, it would be wise to contact the manufacturer and follow any instructions they provide.