Is Hydro-Testing always Required On ASME Code Vessels

[beiringf]

Quick Question: Is it required to always perform Hydro-testing on ASME code euipment. We are currenty building some work bins that are being built to ASME and stamped. Do we need to perform the hydro-test, and if so is this required, and if not, why not? Thanks All, you guys are always great at answering these dumb questions!

 

[SnTMan]

Work bins? Built to ASME what?

 

[metengr]

You can build to ASME B&PV Code and not have the vessel stamped or hydrotested.

 

[weldtek]

A fabricator can also build parts which are Code stamped but not hydro tested. A part may be a simple nozzle assembly or more complex vessel section.

 

[stanrick]

Beiringf,

We build vessels to Sect.VIII, Div.1, per UG-90(c)(2). The vessels cannot tolerate traces of moisture. So we pneumatically test per UG-100, rather than hydro test per UG-99.

The situation, naturally is complicated. First because of the extreme danger of pneumatically testing. Second, some vessels are above MAWP 500 psig and we test to 1.3x MAWP. (REALLY scary) Our AIA advised us that because we do not invoke UG-20(f), we are not limited by the Appendix 35-6 500 psi for pneumatic testing.

So far, the explanation given by our AIA has been accepted by Canadian Regulatory bodies. I conclude from this that the practice is "legal".

Don't know if this helps your situation, it may be food for thought.

 

[beiringf]

Thanks Guys! Once again you have given me the information I need to come up with our solution. Thanks again and keep up the good work!

 

[bernoullies123]

Quick Response: Yes per Section VIII D1 and D2.

There is many caveats that are spelled out in the code, and you need to read carefully.

 

[beiringf]

Here is a little more information I was given to me by our projects group:
The customer wants the equipment fabricated to Sect.VIII, Div.1 and thats it. They are not requiring a hydro test, only a bubble test. I am not sure why they are wanting this as the hydro test is much more extensive and is required when equipment is built to Sect.VIII, Div.1. We are still trying to find out what the rules are...........why would they want this built to Sect.VIII, Div.1, but not proparly tested to Sect.VIII, Div.1. Any comments would be appreciated.

 

[SnTMan]

beiringf, I'm going to say if it is stamped it will be either hydro or pneumatic tested.

Regards,

Mike

 

[beiringf]

it will not be stamped.......i know it would have to be hydro tested if it was.

 

[doct9960]

The customer wants the equipment fabricated to Sect.VIII, Div.1 and thats it. They are not requiring a hydro test, only a bubble test. I am not sure why they are wanting this as the hydro test is much more extensive and is required when equipment is built to Sect.VIII, Div.1. We are still trying to find out what the rules are...........why would they want this built to Sect.VIII, Div.1, but not proparly tested to Sect.VIII, Div.1. Any comments would be appreciated.

Probably, the "work bin" is not a pressure vessel. Your customer may just want the bin designed and fabricated to the ASME Code, but without the stamp, because there is no code for your customer's particular equipment. They probably just want a basis for the design and fabrication of their "work bin", and they chose the ASME Code as the basis.

If you still doubt the customer's intention, go ask your project manager, who for unknown reasons, gives you little information about the work. Go ask him what the "work bin" is for. Would it be categorized as a pressure vessel? Where would this bin be installed? Did your customer checked with his local jurisdiction if work bins need to be registered and stamp? These are questions you need to ask your projects group.

 

[bernoullies123]

As doct9960 points out, I have done the exact same thing. Where we were specifying some odd containment structure, with no particular code it is easier to just specify it to be built to ASME VIII D1 but not stamped. Hence I will get at least 6 mm material and fused together with approved procedures by current welders etc. etc.