12" A-106B smls Pipe/Fittings Schedule true 40(.0406) verses 12" std (.375)

[979Maxwell]

Fly Ash service line any reason why you can't use standard wall verses schedule true 40. There's only thousands wall thickness difference.
Thanks in Advance !

 

[XL83NL]

Whats the service? Whats design temp./pressure? Whats the design code? Any Fluid services applicable?
Any client specs that dictate use of certain fittings? These questions can all influence the answer.

Generally, A106-B is allowed ofr most (typical) services in B31.3 work, AFAIK.
The wall thicknesses differ but not that much; 12" Sch. 40 is 10.31 mm. opposed to 9.53 mm. for 12" STD.
This requires some trimming of the weld bevel in order to account for high-low. This should also be documented in the WPS.

 

[stanweld]

Assuming that Sch 40 is the current piping system as originally specified, the increased thickness may have been due to erosion considerations. Of course you may use Std wall pipe provided the pressure/temperature calculations permit. If you are replacing a section of Sch 40 be aware that the difference in wall at the replacement joints will result in additional erosion at that location.

 

[979Maxwell]

My understanding is flyash is the service and they wanted to use 12" .406 wall but we received standard wall material instead. My question with little wall thickness diffrence what are the pros and cons of using standard wall piping instead of schedule 40 (.406). I do not even have a line schedule which would determine the Temp/presuure ratings.
Thanks

 

[stanweld]

Why not send it back to the pipe supplier? I'm sure you were charged for the sch 40 pipe? Finally, why don't you ask the design Engineer whether you can use the thinner wall pipe and if accepted get the reduced cost from the supplier.

 

[steakman911]

I'm with Stan.....send out an RFI to your client.

stk

 

[racookpe1978]

You MUST notify your client of the difference, but you can do that in such a way as to minimize cost and trouble as well.

"Be aware that, unlike most standard pipe diameters, there are minor wall differences between 12 inch dia Std wall pipe and 12 inch dia Schedule 40 pipe. Unless otherwise directed by 18 September 2013, we will consider both 12 inch diameter Schedule 40 and 12 inch dia Std wall pipe equivalent under specification ABCXYZ 123.456 for use at plant [His Name Here] for the flyash piping. All flyash service pipe fittings and valves will conform to Specification ABCXYZ 123.456"

 

[IFRs]

Standard is 0.375 and sch 40 is 0.406 - to me that is a non-trivial difference - over 8%. This difference increases quickly as the pipe size increases. Perhaps for this application it is inconsequential, but not for most of my work.

 

[racookpe1978]

I agree - There is a difference. We, unfortunately, cannot determine if that difference is going to be critical to his client sometime in the future. HE needs to tell HIS client that the difference exists.

In a nuke service? Reject it!

 

[BigInch]

Somebody needs to call the design engineer to see if the thinner wall is acceptable.

Independent events are seldomly independent.

 

[dcasto]

I can predict the outcome of the questions to design engineers or whomever. It's our standard design, if we change our standard we won't have a standard. Even when you tell the design engineer that the change will save $2,000,000US, they won't care because there design standard book is written in granite.

Good Luck!