Acceptance of Induction Bending of pipe to ASME B31.1 & 3 3

[sadekbenhassana]

Dear all,
Induction bending of pipe can replace a lot of welded fittings. Under what conditions the induction pending can be accepted to be in compliance to ASME B31.1 and ASME B31.3? (maybe the answer already exists in a code interpretation!)
Regards

 

[weldstan]

Any and all but not tight bends where ells are better suited. We normally order induction bends on 8" and greater diameter pipe but I have seen cost reductions from manufacturers in smaller diameter pipe as well.

 

[pradipgoswami]

Hi,
Induction bends are quite popular for any type of pipelines, ref ASME-B-16.49 for manufacturing details.Induction bends are typically applicable for pipes and related bends(long or short radius elbows).
However induction bends are not a full replacement for forged fittings(various shapes) which are an integral part of Process Piping.
Induction bending is quite tricky.Unless well experienced Mills are involved the product consistency could be disastrous, especially for smaller OD pipes,typically 6" and below.
Hence this issue is a very subjective at the discretion of the designer, which any piping code may not accept outright .

Thanks.

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario,Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299

 

[LittleInch]

AFAIK, induction bends are regarded as "unlisted components" as the spec B 16.49 is not listed in the reference standards section. Therefore you need to follow the protocol for such material.

It's unusual to get multiple bends in a single pipe so unless you have lots of strange angles I can't see where the advantage is.

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

 

[XL83NL]

Forget induction bends and read the applicable code section of B31.1/.3 about pipe bending and you have your bending criteria. I believe there's also a PIP standard which can shed some more light on this. [pre][/pre]

 

[metengr]

I agree with XL83NL.

 

[weldstan]

Induction bends are fully used in both B31.1 and B31.3 piping installations and conform to the hot bending criteria stated therein. They are primarily used due to more favorable costs and the availability (poor) of standard wrought ells and "timing as the essence" language in construction contracts. They have been used in projects for which I have been involved for approximately the past 40 years.

 

[ETSeelye]

Regarding forming of pipe bends, I seem to recall that the code (B31.1) requires verification of the wall thickness in the various parts of the bend. Do you guys remember if this is true, and if so, how are those using the process verifying wall thickness? Also, do you check every bend or only some of them? Thanks.