Localized Hydrotest using external jacket to check final Field Weld Joint
Localized Hydrotest using external jacket to check final Field Weld Joint
(OP)
Hi,
We are having few oversized equipment (Height more than 40 m) where due to logistic constraints many vendor's are proposing that they will fabricate the equipment in shop, perform Hydrotest, cut in two pieces, transport them to site, carry out final weld joint at site and perform Localized Hydrotest using external jacket to check final Field Weld Joint.
ASME Sec. VIII Div. 1 does not provide any such guidelines where Localized Hydrotest using external jacket is allowed to check final Field Weld Joint.
Can anybody provide me information whether this procedure of Hydrotest proposed by vendor is acceptable?
If yes, then on what grounds we can accept this w.r.t. ASME Sec. VIII Div. 1 requirements?
If No, then what can be the alternative to carry out Hydrotest of final Field Weld Joint?
Thanks.
Have a nice day!
Ashay Kadam
Sr. Manager
Mechanical Department
thyssenkrupp Industrial Solutions (India) Private Limited (Formerly Uhde India Private Limited)
We are having few oversized equipment (Height more than 40 m) where due to logistic constraints many vendor's are proposing that they will fabricate the equipment in shop, perform Hydrotest, cut in two pieces, transport them to site, carry out final weld joint at site and perform Localized Hydrotest using external jacket to check final Field Weld Joint.
ASME Sec. VIII Div. 1 does not provide any such guidelines where Localized Hydrotest using external jacket is allowed to check final Field Weld Joint.
Can anybody provide me information whether this procedure of Hydrotest proposed by vendor is acceptable?
If yes, then on what grounds we can accept this w.r.t. ASME Sec. VIII Div. 1 requirements?
If No, then what can be the alternative to carry out Hydrotest of final Field Weld Joint?
Thanks.
Have a nice day!
Ashay Kadam
Sr. Manager
Mechanical Department
thyssenkrupp Industrial Solutions (India) Private Limited (Formerly Uhde India Private Limited)





RE: Localized Hydrotest using external jacket to check final Field Weld Joint
RE: Localized Hydrotest using external jacket to check final Field Weld Joint
My first question would be, why can't they hydrotest the complete vessel on-site? (weight? internals that can't get wet? ...?)
The other route I've seen would be:
RE: Localized Hydrotest using external jacket to check final Field Weld Joint
RE: Localized Hydrotest using external jacket to check final Field Weld Joint
2) Final weld in site
3) Hydrotest in horizontal position.
Regards
r6155
RE: Localized Hydrotest using external jacket to check final Field Weld Joint
RE: Localized Hydrotest using external jacket to check final Field Weld Joint
Too much energy in a pneumatic test. The exclusion distance would be excessive and the consequences of a failure under test - don't want to go there!!!!
RE: Localized Hydrotest using external jacket to check final Field Weld Joint
General Blr. CA,USA
RE: Localized Hydrotest using external jacket to check final Field Weld Joint
Especially if the shell is large relative to its thickness, the collapse pressure may surprise you.
The collapse event certainly will; hell of a bang.
Mike Halloran
Pembroke Pines, FL, USA
RE: Localized Hydrotest using external jacket to check final Field Weld Joint
RE: Localized Hydrotest using external jacket to check final Field Weld Joint
RE: Localized Hydrotest using external jacket to check final Field Weld Joint
There is no harm in doing a field hydro-test using limpet coil, i.e., a half pipe welded inside the vessel on the field weld. It is safe as well.
Of-course there needs to be a proper method statement from your manufacturer, which should cover the method of welding the coil to the vessel. If PWHT is there, then needs to be PWHTed as well. Proper NDE after removal of coil, etc.
Requires some mind-work but safe and sound practice it is.
As far as acceptance based on code is concerned. Do apppreciate that code doesnt specify about shop or field hydrotest. neither does it restrict any field/local hydrotest. your apprehension is a consequence of lack of exposure/experience in such techniques.
RE: Localized Hydrotest using external jacket to check final Field Weld Joint
RE: Localized Hydrotest using external jacket to check final Field Weld Joint
Ashay Kadam
Mechanical Engineer
India.
RE: Localized Hydrotest using external jacket to check final Field Weld Joint
Then make the strake where the vessel is cut in half thicker so the site Pneumatic test provides no more risk than the risk while applying MAWP to the vessel.
This solution is about reducing risk to less than what would be experienced during operation.
RE: Localized Hydrotest using external jacket to check final Field Weld Joint
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.