pipe size 2

[26stinger]

When do change from I.D. to O.D. in sizing pipe?

 

[DSB123]

26stinger,
Sorry but your question is un-clear. If you are asking about sizing pipes for flow of fluids then the ID is always used. If you are asking about actual pipe sizes then these are based on the Nominal Size (e.g. 2",3",4",6",8" etc). The actual ID of a pipe is dependant upon the pipe schedule. The OD of an actual pipe is dependant on the pipe size. For example we have:-

Nom Pipe Size Pipe O.D. Pipe I.D.

3" 3.5" Depends on Schedule
4" 4.5" Depends on Schedule
6" 6.625" Depends on Schedule
8" 8.625" Depends on Schedule
10" 10.75" Depends on Schedule
12" 12.75" Depends on Schedule

14" and Above - the Pipe OD is the nominal size of the pipe and the ID depends on the pipe schedule.

 

[davefitz]

Id is always less then OD, or else the hole will fall outside of the pipe.

 

[JStephen]

Note that the dimensions above are for steel pipe. Ductile iron, PVC, and other pipe types will vary in dimensions.

Large-diameter steel pipe can be custom made in varying OD's as well.

 

[AravindSujay]

Hi,

When you measure the flow quantity or volume of the liquid inside, then ID should be used. When you measure just the pipe size, nominal size or OD should be used.

Thanks,
Aravind Sujay

 

[heatexguy]

Up to 12" NPS is ID, 14" NPS and larger is OD, I believe this answers the question. 12" pipe is 12.75 OD, 14" pipe is 14" OD.

 

[JLSeagull]

Up to NPS 12 from where and at what schedule and material?
Is it really that easy? I don't see it. Consider using ASME B36.10 for steel and B36.19 for stainless. That's what I do and it usually works for me.

 

[BigInch]

Its that easy.

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