Is the longitudinal weld of a hot-tap split tee with a backing strip considered in-service? 1

[zengx]

We are reviewing a WPS for a Split-tee hot-tap in accordance with API 1104 Annex B. In the WPS, the contractor is considering all the welds of the split-tee to be in service, including the longitudinal joint that has a backing strip, and they are considering the essential variables only in Annex B.

We are having a different interpretation that the longitudinal weld of the split tee should not be considered "in-service" since we will not touch the existing pipe. This means that they have either to separate the circumfrential "fillet" weld and the longitudinal welds in the WPS (since the essential variables for each will be different), or submit two separate WPS for each.

I've tried searching different standards, and found no clear categorization of this longitudinal, either in-service or not.

Is there any reference supporting one of the above interpretations?

Mohammed Diab.
Inspection Supervisor - Saudi Aramco.

 

[Duwe6]

Easy answer is "Who is the API Inspector of Record for this job?".
API Guys get a lot of latitude in making 'fine' calls like this one, thus the lack of ASME-type nitpicking guidance in the API codebooks.
And if I was making that weld, I would declare it to be In-Service for the purposes of the Hop-Tapping. And demand some way to monitor continuous flow in the line during welding. It's gonna get hot in that live line. As for WPS purposes, if there is actually a backing strip used, and the fit-up has a reasonable gap, this is just another weld. API-1104 gets weird on a bunch of things when compared to ASME VIII & IX and API-650 & 653, and this is one of them.

 

[SJones]

Is the text of API 1104 not clear:

Annex B, third sentence "In-service welds are defined as those that fuse directly into the wall of an in-service pipeline...."

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[zengx]

Thanks Steve.

Mohammed Diab.
Inspection Supervisor - Saudi Aramco.