Guide to.. Round Pipe Measurements
Nominal Bore (NB) & Outer Diameter (OD)

NB (nominal bore) is also frequently used interchangeably with NPS (nominal diameter).
OD is the outside diameter of the pipe and is fixed for a given size.

To find out the outside diameter, and what is considered Extra Light, Light, Medium or Heavy Gauge please see the table provided.

So what's the size? 

We've made a chart for you to find out what the size conversions are! 

Nominal Bore Size Pipe Conversion Round
Want to download a copy? Click below!
Guide to Rising Hinges
When you need the gates to rake up
2023 Catalogue