B31.3 PWHT of a closure weld, am I required to hydrotest it after PWHT is complete?

[kelaog]

Hi all,

I could not find an answer in the B31.3 interpretations. Here is my problem. I am required to do several closure welds in various projects. The pipe spools being installed are pressure tested; however, the final connection will require a closure weld. The client also requires me to PWHT these line classes (Sour). I was under the impression that a closure weld was exempt from hydrostatic testing but the clients construction manager is telling me that if we PWHT the closure weld afterward then am I required to hydrotest the weld. So I ask, if I PWHT a closure weld am I required to hydrotest it after the PWHT is complete? For reference this job is being complete in Canada (BC).

Section 345.2.2 Other Test Requirements (B) states:
Heat Treatment. Leak tests shall be completed after any heat treatment.

Section 345.2.3 Special Provisions for Testing
(c) Closure Welds.
The final weld connecting piping
systems or components that have been successfully
tested in accordance with para. 345 need not be leak
tested provided the weld is examined in-process in
accordance with para. 344.7 and passes with 100% radio-
graphic examination in accordance with para. 344.5 or
100% ultrasonic examination in accordance with
para. 344.6

 

[pennpiper]

kelaog,
As you pointed out in this paragraph you posted in your question post.
Section 345.2.3 Special Provisions for Testing
(c) Closure Welds.
The final weld connecting piping
systems or components that have been successfully
tested in accordance with para. 345 need not be leak
tested provided the weld is examined in-process in
accordance with para. 344.7 and passes with 100% radio-
graphic examination in accordance with para. 344.5 or
100% ultrasonic examination in accordance with
para. 344.6

You have a choice of two options -
1. 100% radio-graphic examination in accordance with para. 344.5
or
2. 100% ultrasonic examination in accordance with para. 344.6

You may want to discuss this with you AI (Authorized Inspector)

Sometimes its possible to do all the right things and still get bad results

 

[kelaog]

Pennpiper, thank you for your reply. Either I don't understand your answer, or you haven't understood my question. I would think I've probably misunderstood your answer due to my lack of experience. In which case, I appreciate you taking the time to answer my question. Perhaps you can clarify?

I realize that you can do in-process examiniation in lieu of a pressure test. Sometimes this is referred to as a golden or closure weld procedure which is 100% mpi of the root pass (although not required, but typically industry standard) and RT or UT of the final pass.


However, because I'm required to do PWHT of the closure weld. Am I required to now hydrotest it based on 345.2.2 para (B). In which case these two clauses are conflicting each other which is why I've posted both.

Or are you telling me that after I'm done PWHT I can do 100% UT or RT of the cap and I am still meeting 31.3 requirements. I believe typically these are done after PWHT anyway.

So to clarify, the closure weld procedure in my case would look like this.
Root pass
100% MPI
final pass
PWHT
100% UT/RT

No pressure test required.

 

[metengr]

Hydrostatic testing is not required to be repeated for welds identified under 345.2.3.

 

[Ishack]

Section 345.2.2 states that any leak test that is to be carried out only after PWHT if PWHT is required for the weld as per the piping class and it doesn't mean that the closure weld to be pressure tested if PWHT is performed on it.

Pressure test can be waived off / exempt for closure weld provided the requirements mentioned in section clause 345.2.3 ASME B 31.3 fulfilled.

Regards,
ISHACK M