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Pipe Fabrication Tolerance as per ASME B31.3

Pipe Fabrication Tolerance as per ASME B31.3

Pipe Fabrication Tolerance as per ASME B31.3


Can anybody help me to solve this issue.

I want to make a fabrication tolerance standard. Please give me the details of allowable tolerances (Linear and Angular) for pipe fabrication as per ASME B31.3.

RE: Pipe Fabrication Tolerance as per ASME B31.3

B31.3 does not list these tolerances in a manner that you're probably after. B31.3 has certain criteria on fabrication, but not such specific tolerances. You need to set these up yourself. You can use industry practices such as PIP PNSC0001 en PFI ES-03 as a good starting point.

RE: Pipe Fabrication Tolerance as per ASME B31.3


Thanks for your reply.

The problem is that my client is asking code/Standard reference to prove the allowable tolerance.

I already adopted normal industry practice for my fabrication allowance.

For Angular allowance I got some reference from B31.3 Para 335.1. But it doesn't giving any clear picture about linear allowance.

"You can use industry practices such as PIP PNSC0001 en PFI ES-03 as a good starting point." Is this approved by ASME or not?

RE: Pipe Fabrication Tolerance as per ASME B31.3

I assume from your reply that you've read chapter V of 31.3.

If so you will see there is little there.

Your client appears to be an idiot who is looking for a crutch. It is not up to any code or standards agency to come up with fabrication tolerances like you are asking for.

This is part of the fabrication specification you have seemingly written and your response to the comment / question is "there are no code mandated requirements, however these are industry recognized figures and we would recommend them to be used."

Then let him come back and instruct you to change them.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Pipe Fabrication Tolerance as per ASME B31.3

Hi LittleInch,

Thanks for your reply.

Yes my statement was related to chapter V.

Sometimes it's very hard to explain/get it understand to a client/Managers who doesn't have any idea about piping.(Unfortunately in my case they are from Structural side).

I already prepared a standard based on the industry practice and referring PFI-ES-03. I hope this will work out.

Anyway thank you all once again for the replies.

RE: Pipe Fabrication Tolerance as per ASME B31.3

If you have already prepared a "project Specification" covering your Pipe Fabrication (including a reference to "PFI-ES-03) then you have done your job. It now becomes the job of someone in your Companies Management to educate the MBA-Heads in the client's management that Piping is done by Professionals who know what they are doing.

Based on the information you have provided I would say you have done the right thing and you now should just stand your ground.
There are lots of people out there in this big wide world who do not know anything about the length, width, depth and complexity of the Piping Profession. Just try to explain it to members of your family at the next family get-together.
Go here for more on this subject:Piping, The Hidden Profession

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

RE: Pipe Fabrication Tolerance as per ASME B31.3

One option is to contact the pipe manufacturers, and ask what are other industrial standards used for fabrication.

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