SA106B vs SA210A

[kouter]

Can SA210A be substituted with SA106B in an evaporator panel application? I'm getting conflicting responses from boiler manufacturers. Many want to switch it out to the cheaper piping but is this against code?

The two materials seem nearly identicle. Is the main defference in heat transfer? If so, what is ther difference? And can this substitute be made?

Thanks,

Kirk

 

[stanweld]

SA210 is a tube spec. OD and thickness are different from SA-106 B, pipe spec.

 

[kouter]

Thanks Stanweld. Are the physicial thicknesses the only differences?

 

[boilerone]

The answer is "yes, you can". It is actually one of the topics and answer from an official ASME Section I training course that I went to plus this had been done many times in realities. While using SA106B to substitute SA210A(A1, to be exact) for a heated service please pay attention that:

1. The allowable stress values are not exactly the same.
2. Make sure to use PG27.2.1 tubing calculation formula instead of PG27.2.2 piping formula in ASME Section I. By ASME, a piping application is intended for transferring fluid and a tubing is for heat-absorption therefore, even though you are using a pipe material but since it is actually a tubing application, you must use the tubing formula.

 

[kouter]

Many thanks Boilerone!

Would you be able to point me to an extract which has this information. I may need to convince a QA of its acceptability via ASME standard.

Regards,

Kirk

 

[metengr]

Boilerone is correct. This is more of a design issue and is not going to be addressed specifically in Section I unless there was an inquiry, which could be used as reference. Either way, SA 210 tube material could be used provided a design review has been performed and tube size and schedule have been confirmed by code calcs.

 

[boilerone]

The ASME explanations for the intended applications of and differences between formulas PG27.2.1 and PG27.2.2 are seen in Interpretations 1-83-47 and 1-86-25.

Regarding official languages in ASME to allow pipe materials to be used in heated services, I haven't found any myself. You might have to contact ASME committee for answers but, as I mentioned, it is a very common practice to use pipes inside a furnace or flue gas path. Examples are evaporator wall headers and economizer headers plus many components of special dimensions that are not available with tube materials. Nevertheless, I haven't seen using large quantities of pipes to substitute tubes but the main reason is because that if you need a lot of tubes you can always get a special order from the manufacturers without having to find off-shelf items. For your special situation of, I assume, unable to find the exact tube material without high cost and can't get an AI or QC to approve using an existing available pipe material as substitute, see if you could contact the supplier to check the material test report and if they also qualify for the specs of the tube that you are looking for, the supplier might be able to re-certify these pipes as tubes. It is very common to see dual-certifying materials on the markets. For the dimension and tolerance differences, either you can change your design documents (after calculations and necessary drawing changes, of course) of the tube specs to match the pipe's or the supplier might be willing to machine, at a small cost, the OD's and ID's of the pipes to meet the requirements of your tubes. This (machining to meet requirements) was heard done quite often before.