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Dumb Question
Posted: Sun May 18, 2014 10:22 pm
by pipelinedreams
But what does SCH mean in welding terms like when people say ( 2'' sch 160 ) what does that mean?
Re: Dumb Question
Posted: Mon May 19, 2014 9:36 am
by weldin mike 27
Hey,
No dumb questions here,
It means schedule. Im not a pipe man so i dont really know how it all fits together.
http://www.universal-stainless.com/excel2.jpg
Ps i will move this to General Shop talk.
Mick
Re: Dumb Question
Posted: Mon May 19, 2014 9:41 am
by weldin mike 27
Re: Dumb Question
Posted: Mon May 19, 2014 12:10 pm
by AKweldshop
It means thickness of the wall of the pipe.
Sch 10 is thin wall, sch 160 is thick wall..
John
Re: Dumb Question
Posted: Mon May 19, 2014 12:17 pm
by kermdawg
Pipe is rated by inside diameter while tubing is rated by outside diameter. Pipe goes by schedule, tubing by standard, heavy, x heavy etc... 6" pipe is actually 6-5/8" od. 6" tube is 6" od.
Re: Dumb Question
Posted: Mon May 19, 2014 3:21 pm
by coldman
Pipe has a constant outside diameter which is always a bit larger than the nominal rating diameter. Pipe inside diameter varies according to the pipe schedule unless it is linepipe which describes wall thickness as standard weight, extra strong, extra extra strong etc. These thicknesses mostly equal schedule sizes but not in every case.
Tube is rated on the outside diameter and specified wall thickness.
Can be confusing. I suspect it may have British origins which helps understand why it is confusing.
Re: Dumb Question
Posted: Mon May 19, 2014 3:29 pm
by kermdawg
Always thought it had to do with piping being used to convey a fluid And tubing usually being used for structural purposes
Re: Dumb Question
Posted: Mon May 19, 2014 6:24 pm
by noddybrian
Most pipe spec is fairly specific to it's application - BSP has been a standard here for years - defining a pipe by it's nominal bore - you then would have to look up it's OD in tables - the trouble is this only holds true for low pressure pipe used for water lines & gas etc at domestic pressures - but having already defined the thread dimensions used to join this & all related fittings if you need a higher pressure rating then the OD stays the same & the bore is reduced to give greater wall thickness - confused yet ! - it's actually not unlike your schedule system - I believe what we would generically call " black iron " would be your schedule 40 - I remember looking a bunch of them up when I was trying to find a suitable size heavy wall pipe to replace a damaged axle tube on a Harley that was converted to a trike - ended up with 1-1/4" bore schedule 160 I believe - closest match I found to the original - the real headache is usually when you need to find two pipes that fit well inside each other.