hydrostatic testing requirement after erection... 4

[emree]

hii ...
in our project, for the asme U stamped equipments( already erection was done) an extra hydrostatic test is asked by our client...all we know that hydrostatic tests were done by manufacturer ...does anyone know that any asme code require hydrostatic testing after erection...???I looked in asme sec8 but does not mention about it...thanks...

 

[metengr]

an extra hydrostatic test is asked by our client...all we know that hydrostatic tests were done by manufacturer ...does anyone know that any asme code require hydrostatic testing after erection.

No, unless further weld fabrication is required for a final ASME stamp. If all the data reports and Code stampings are in order, a repeat hydrostatic test is a waste of time and money.

 

[deanc]

metengr is correct for the vessel itself.

Perhaps your customer wishes to check for leak tighness of the entire unit. That would be good practice and I would recommend if practical.

It is sometimes unwise to go to the orginal test pressure of the vessel. A reduced pressure hydro or gas test may be in order.

If the user will pay for it.....what does it matter?

 

[rzrbk]

A leak check at operating pressure can be worthwhile on equipment such as exchangers and fin-fans(to check for tube-roll leaks, etc), less so on pressure vessels.

I am used to the equipment and foundations being specified such that a field hydrotest can be supported in the future, but have not generally seen a hydrotest required for new equipment.

 

[JoeTank]

Gentlemen,
There is a great risk in performing a hydrotest of the system if the sysytem was not designeded for the weight of the hydrotest water. Be sure to check that the vessel supports, the support structure and the foundations are syuable for the water load.

Joe Tank

 

[doct9960]

emree,

Are the vessels and foundations designed for a field hydrostatic test in its operating position, with all those connected piping (full of water) and other loads such as wind considered? This is particularly important on those tall towers or columns.

 

[dcasto]

Unless your client is super rich or doesn't understand plant construction, there reason to do another test is a leak check. As ponted out,the foundations may not be designed for 100% full of water. Normally, major vessels and towers are blinded from a hydro-leak test of the assembled piping. I always opt for a pnuematic test at this point to save cleaning and drying of the piping.

 

[deanc]

You are all correct in the weight concern with water. I was not clear on that.

The NBIC is a good guide.

 

[MJCronin]

emree,

What has not yet been mentioned is the hydrotesting of the piping system.

It was my understanding that the "system pressure test" was a test of the interconnecting piping system as well as an in-place testing of the ASME-VIII components.

Of course, with non-flanged (welded nozzles) at the equipment face, there is no other way to test the piping without either a "golden weld" provision in the test proceedure or a pressure test of the equipment at the same time.

-MJC