HYDROTEST after steam blows. 2

[GBENARD]

We have performed a complete hydrotest of the boiler before the steam blows. After this phase, we have to cut the steam pipes (3 pressure level boiler) to install and weld the flow nozzles. Unlike most of our previous projects, the nozzles are installed upstream the code stop valve (boiler external piping).
Up to now, our standard practise is to weld and perform 100% Xrays.
Now it seems that according to ASME B31.1 (§137.8)/ASME I we should have to perform a new hydrotest after the installation of flow nozzles. How could I manage to avoid that?

 

[metengr]

GBENARD;
If I understand your question, the steam flow nozzles are installed upstream of the code stop valve. If this is the case, the piping supplied between the superheater outlet header and the boiler stop valve would fall under ASME Section I/B31.1. As such, Section I has administrative authority, and you would have to subject the piping segment that was installed with welded flow nozzles to a second hydrotest in accordance with ASME B31.1, paragraph 137.8 (and PW-54.2 in Section I).

If you installed the flow nozzles downstream of the boiler stop valve, this would fall under nonboiler external piping (B31.1). Most Jurisdictions do not typically enforce ASME B31.1 nonboiler external piping. The only way to avoid not having to perform a second hydrotest of the piping section containing the welded flow nozzles would be a waiver by the Jurisdiction (if applicable)and the owner. For nonboiler external piping outside of Jurisdictional control, the owner would have to agree to your proposed method of 100% RT inspection.

 

[unclesyd]

As meteng states you need to have a low talk with the jurisdictional authority and owner.

Is there another weld in the line closer to the boiler?

What is the material specification of the steam line you are going to cut and weld?

Did the drum undergo PWHT and how long were the attached nozzles?

Does the piping being installed require PWHT?

What are the design conditions for the boiler?

 

[GBENARD]

Thanks for your answers,

The flow nozzles I am talking about are located on the Boiler external piping between superheaters outlet headers and the code stop valve. Two of them (Low pressure and medium pressure steam) are plain carbon steel pipe (A106 B or something) and we do not expect to have to perform any PWHT. The last one is HP steam. This is P91 piping designed at around 570°C/130 barg, pwht is, of course, required.

Anyway, one of my contacts told me that we may rely on interpretation I-89-50 quote "after the AI has signed the master data report for a complete boiler, the boiler is no longer under the jurisdiction of the code. Accordingly, no further testing is required" unquote.
How should I understand that?

 

[unclesyd]

I think your contact is in error.
It all depends on how the AI interprets the work you are going to do. That is why the AI has to be in the loop and you should seek prior approval before you start any work. The AI will normally work with you in everyway possible to keep from recharging and hydrotesting the boiler again.

You need to get the AI on board and on your side ASAP.

I hope that when you shutdown the boiler and drained it the proper precautions were taken.

 

[metengr]

The issue is after the master data report has been officially signed indicating ALL design/fabrication/erection has been completed in accordance with the ASME B&PV code (Section I), any subsequent work would be a repair/alteration under the National Board Inspection Code (NBIC).

What I do not understand is why the flow nozzles are added AFTER the completion of the boiler? Is this for performance of steam blows or some other reason? You must run this by your AI, as stated by unclesyd, and should discuss this with the Jurisdiction to assure you are covered. Adding flow nozzles in my opinion means that the boiler was NOT completed prior to the hydrotest, but that is for AI and Jurisdiction to decide!.

 

[qualitypro]

GBERNARD,
As your Flowmeters are falling under the jurisdiction of ASME SecI/B31.1:BEP you have to keep your AI in the loop. Flow meters are usually left out until the steamblows are completed. As per the code, the BEP piping system can be accepted ONLY by a rehydrotest. Please do check the Data Reports for the Flowmeters in question. There is a strong possibility that they would NOT have been shop hydrotested. If that's the case then it would be very beneficial to hydrotest the Flowmeters at site to assure ourselves.

 

[pmover]

my only question is that why weren't the flow nozzles installed by boiler oem if end-user required them at location upstream of stop valve? the subsequent testing would have been an opportune time to test the flow nozzles.
definitely concur with metengr recomendations.

good luck!
-pmover

 

[GBENARD]

OK.
I think I have a clear picture, even if not so nice. Thanks everybody for your advises. Concerning the installation of the flow nozzles after steam blows, there are few explanations. first, we do not want to have any restriction in the circuit during steam purging. Second, these items are quite precisely manufactured and we do not want to scratch them during the procedure. The problem we have now is new for us because we normally do not have the required straight lengths available on the piping upstream the code stop valve.

 

[GenB]

ASME or NBIC or not, you will have to test.
und unless you can perfectly plug the boiler outlet, you will have to flood the boiler.
I am not sure if you are even allowed to have a device between the boiler and the valve. It may be but then you have to comply w/blr external piping.
ER