Nominal Pipe Size

[jrrocks]

When we are referring, 1/2" Nominal Pipe size for chilled water supply, what does it mean?
This 1/2" is Internal Diameter of that pipe? or what?
Pipe diameter mentioned in design drawings is NPS or ID of pipe?

 

[LittleInch]

Depends what material, who you buy it from and which specification / code you use.

So steel pipe supplied to the dimensions in ASME B36.10 NPS of 1/2" would have a fixed OD of 0.840 inches with a varying wall thickness.

Tubing on the other hand could be quite different as would PVC, PE or "hose", all of which could be called NPS 1/2".

In general the ID should be at least 1/2", except for a high pressure hose.


Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[MintJulep]

Pipe sizes are very simple.

If you measure a pipe, and no dimension is 1", then it's 1" pipe.

thread404-293276

 

[dbill74]

When you say 1/2" NPS, the internal diameter ID is approximately 1/2". The exact ID is going to vary slightly depending on the material of the pipe, but you are talking about hundredths or thousandths of an inch. Actual ID, wall thickness and OD vary depending on the material and gauge of the pipe.

For example 1/2" copper tube has an ID of 0.527" to 0.569" depending on whether you're talking about Type K, L or M tubing.
ASTM B36.10 (Welded and Seamless Wrought Steel Pipe) referenced by LittleInch has a standard ID of 0.622" and varies depending on the gauge (wall thickness) of the pipe.

 

[LittleInch]

dbill 74 - To be a little pedantic - the ID which arises from use of STD / schedule 40 wall thickness results in an ID of 0.622", but the OD of NPS 1/2" pipe is the bit that is fixed. Very few people I know would refer to this as a standard ID...

Hence a thicker wall than STD results in a smaller ID.

The thickest pipe at 1/2" in B36.10 (XXS) has an ID of 0.252" (!!)

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[jrrocks]

Thank you all...!!!