Pipe Wall Thickness

I wouldn't worry about.

As you have noted there is no standard sch. 60 - it would have to be custom fabricated; but the biggest thing to note is that with those specified conditions you require a wall thickness of 0.467" seamless (B31.3). You should just go with schedule sch. 80s (t=0.500"). The wall thickness of double butt weld electric fusion pipe would be 0.517", which is already over sch. 80s. Therefore you would need custom seamless pipe for off schedule and that DEFINITELY is not worth it. Just go with sch. 80s (seamless).

................... uh-ohhh - something else donned on me. Mill tolerance on pipe wall thickness. I believe on A312 it is 12.5% under on thickness (I don;t have access to that standard at the moment). Therefore the min wall you can assume for sch. 80s pipe is 0.4375; which is over the min. thickness you require for those conditions. I would confirm that pipe spec you have there and definitely look into that corrosion allowance. The other way around this is extensive wall thickness testing - or specifiying a minimum wall thickness to the supplier - both will add cost.

?!?!?!?!?!

Re-reading your question again. Are you sure that is the specified pipe spec?? I noticed you mentioned EFW. What piping code is that spec to?!!?!?

Code is ASME B31.3

Thanks for comments.

Something is wrong then (I am pretty sure my numbers are correct).

The only way you could get away with welded pipe with that design is if you did 100% radiography of the welds and confirmed the minimum thickness (with mill tolerance) is above what you require as per B31.3 - 304.1.2

............. or get rid of that corrosion allowance. What's the reasoning behind so much, particularly on stainless?

I may be missing the point But on this link is a PDF of all the pipe sizes standard and non standard http://www.tubularsteel.com/products_welded.asp

If I am understanding 20 s60 is .812 wall OD is 20.0

Hope this helps

Ladish "Table of PROPERTIES of PIPE" lists Sch. 60 20" pipe wall thickness as 0.812 as reported in a previous thread.

I have an old hard copy of this which quite extensively lists the specs for pipe nominal diameter of 30".

I suggest that you search for the Ladish Web site and see if they post this there. I did not check myself.

Dam - that is the easy answer. I really have to slow down with my answers and not got caught up in details / with blinders on. I got caught with the screwball of the B36.19 standard which was developed specifically for stainless to give options where a corrosion allowance isn't necessary.

The easy solution to the problem is to go with B36.10 pipe as others have mentioned and drop the whole 'S' designation in the pipe schedule.

(........ kicking myself in the a$$ for not catching this )

corrosion allowance on a SS 316 is very strange.. i've never seen it... are you sure that a corrosion allowance is required???

S

corrosion control