Spec break

Date 03-13-2014 20:53

What service? In my experience, spec changes occur at the battery limits or at metering stations? The P&ID should have this information drafted onto it, or at a push, the Isometric.

By js55

Date 03-13-2014 20:59

There is no necessary code break. If you do not have the info available in your contract docs contact your customer.
Another thing, in my experience 1104 is seldom imposed without B31.8 or B31.4. There are things 1104 simply does not cover.
So there is not necessarily a break at all. It may be both.

By WELDICCAWSCWI (**)

Date 03-13-2014 21:06

on this project it is api 1104 from the pipeline to the metering station at which
point it turns in to B31.3 we have weld weld olets on the 1104 side somebody
who is no longer here penciled in a spec break between the top of the weldolet to the branch pipe . were trying to verify in which code it confirms this notation

By js55

Date 03-13-2014 21:11

I'm curious, are you working both sides of the code break line?

By 46.00

Date 03-13-2014 21:19

Would these weldolet perchance be supplying instrumentation or flow monitors?

By 46.00

Date 03-13-2014 21:16

As I understand, and I may be wrong here, if B31.8 is used, it should be shown on the plot plan and has jurisdiction over B31.3 limits?

Ultimately, it is up to the 'owner' to determine what standard applies to his pipe and where changes are required.

By dbigkahunna (****)

Date 03-17-2014 23:23 Edited 03-17-2014 23:31

B31.8 is for gas and B31.4 deals with liquid pipelines.
The break from the pipeline to the plant/compressor which will be under B31.3 will USUALLY be at a valve. If it is a weld on valve, one side of the valve is covered under 1104 and the other weld is B31.3. In some places it is a fence. And yes you can have one welder welding DH on one end of the joint and another welder welding UH on the other end.
If this O Let will be the break there should be a valve on top of the O Let and then everything behind that valve will be considered "plant" work under B31.3. When the flow comes back to the pipeline, there will be another O Let downstream from the first one with a block valve between them.
When the valves on the O Lets are open and the block valve closed the flow goes to the "plant" or compressor station. When the valves on the O Lets are closed and the block valve opened the flow bypasses the plant or compressor station.
When it hits the valve again everything behind it is B31.3 and on the other side of the valve it goes back to B31.4 or .8
When you read B31.4 and B31.8 it will give the NDT requirements, etc, based on the location of the pipeline.
A line in a high consequence area will require more NDT than a gathering line out in a pasture.