Steel Pipe size

[John Cobb]

I don't claim to know everything about pipe & tubing, but a metal supplier tried to sell me some 2-7/8 O.D. with a wall thickness of approx. 0.165 as 2-1/2" sch.40 pipe. To my knowledge it should have been around 0.203 give or take a couple of thousandths.
My question is, isn't pipe below 12" measured by I.D.& sch. and tubing is measured by O.D.& wall thickness?
Any clarification on this would be helpful. Thanks,
John

[Roger]

Small pipe size is a nominal measurement.
Pipe's ID might be close to some common unit of measure for a given schedule but that isn't the pipe size. 1" pipe has different ID for schedule 40 or schedule 80.

[Will]

John,
I have attached a .zip file that contains an Excel file with the ID and wall thickness for the various pipe sizes and schedules. Hope this helps.

[linngl]

2-7/8' sounds like oilfield tubing. The 2-7/8" is for the upset measurement (on the ends), 2-1/2" is the body measurement. Petroleum engineers are concerned with tensile strength and burst strength. These measurements are critical in knowing displacement, clearance and fluid flow properties. Oil field tubing isn't rated by schedule.

[d.paulson]

Pipe and Round tubing is not the same. Pipe is painted black and designated by a schedule. Pipe is used for transporting gas, oil air etc under presure. Round tubing is NOT to be used in these situations. Round tubing is designed for structural applications only. Round tubing is measured by it's OD and wall thickness. Generally round tubing is cheaper than pipe.