Pipe Schedules and Wall Thicknesses 2

[jdogg05]

Please, what is the purpose of STD, XS, and XXS pipe? Does this just give the designer a larger range of wall thicknesses for a given pipe size (at pipe sizes 10" and above for STD and XS, and for pipe sizes 6" and below for XXS)?

There is no material difference or anything?

Also, I have seen 16" XXS pipe on ISOs, but I can't actually find any tables online showing the wall thickness for this...

 

[XL83NL]

The relation between wall thickness and schedule is listed in ASME B36.10/19.
Schedules have nothing to do with pipe material, just as speed isnt reserved only to Ferrari, but to cars in general; every pipe has a wall thickness, and is made of a certain material grade.

 

[SlideRuleEra]

16" XXS Pipe wall thickness = 40.49 mm
See this table:

http://www.fittings.com.tw/news/Pipe's Wall Thickness.pdf

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[BigInch]

Does this just give the designer a larger range of wall thicknesses for a given pipe size?

YES

you must get smarter than the software you're using.

 

[MortenA]

@jdogg05,

Maybe i didnt quite understand you question, but i have the following to add about schedules for piping: It would not be economical in most cases to have the optimum wall thickness for each spool in a plant because there would be so many. So a system of schedules have been developed that the pipemills can produce to - making the fabrication more economical. Please note that i many pipe class systems its not the pipe as such that determines the "max design pressure of the class but the flanges (and dont do as i did in the beginning and confuse pipe class and pipe schedules).

 

[LittleInch]

Try reading the foreword (I know not many do...) of 36.10. I think the original idea behind the schedule nos etc was to allow a standard schedule number to be used for a variety of pipe sizes for the same pressure rating. However...

"The original intent of the Committee was to establish a system of Schedule Numbers for pipe
size/wall thickness combinations which would have an approximately uniform relationship equal
to 1000 times the P/S expression contained in the modified Barlow formula for pipe wall thickness
as defined in the Appendix to this standard. The resulting Numbers departed so far from existing
wall thicknesses in common use that the original intent could not be accomplished. The Schedule
Numbers were then adopted strictly as a convenient designation system for use in ordering."

And for XS, XXs etc

"It was the hope in 1939 that the designation of pipe used commercially by all industry as
Standard weight, Extra-Strong, and Double Extra-Strong would gradually be replaced by Schedule
Number designation. However, owing to customs of over 50 years’ standing, demand and production
of pipe to these traditional dimensions is undiminished. Consequently, in response to a
demand from users, accepted practice for dimensions and weights of commercial wrought steel
and welded wrought iron pipe were added."

In some pipe sizes std and XS etc correlate to a schedule number and in some others they don't....



My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way