18 Jul Simple Guide to Pipe Size Terminology
It can get a little tricky sometimes when trying to make sure you order the right pipe for the job. Some manufacturers talk in terms of nominal bore, some talk about inside diameters and yet others will send you measurements in outside diameters. So, what is the difference and how do you make sure you are getting the right pipe for the job?
Outside diameter (OD) is measured from top to bottom, or left to right from the outside edges of the pipe – not the collar or socket end. The OD is often critical for joining pipes or getting the correct fitting that will fit over the pipe.
Inside diameter (ID) is measured from top to bottom, or left to right from the inside hole of the pipe. This measurement is important when calculating the flow of liquid.
Nominal bore (NB) is never an exact measurement. By definition, ‘nominal’ means in-name-only, or a referenced name. The problem with nominal bore measurements is often the part number uses nominal bore not the actual size you are looking for.
Download our guides below that further define these terms with regards to specific stock.