What is nominal pipe sizing

Inch sizes relate to the nominal (approx.) bore of the PIPE and are not literal physical dimensions. For instance, 2" pipe is NOT 50mm outer diameter, so the sockets of 2” fittings DO NOT measure 2” internally.

Although eeziflo lists pipes and fittings at 2” in size, the most important thing to remember is that the pipe or fitting WILL NEVER EQUAL 2” wall to wall, or of any 2 opposite sides of the pipe.

PVC Pipe OD

The OD (Outer Dimension) of PIPE

For example, when we say the size is 2”, it refers to the approximate nominal bore of the pipe, the outside diameter of which is approx. 2.380 inch or 60.45mm, irrespective of wall thickness, which can differ according to the pressure class, thus affecting the nominal bore.

PVC Socket Fitting ID

The ID (Inner Dimension) OF A SOCKET FITTING

Conversely the ID (inside diameter) of the socket of fittings does not equal 2 inches. It measures approx. 2.380 inch or 60.45mm, so that the pipe can fit snugly inside before being glued in.


Please always refer to the relevant Data Sheets for the specific pipe, fitting, valve or flange you’ll be looking at before purchasing.

The customer agrees to all pipe, fittings, flanges and valves order in inch sizing to arrive in nominal sizing.

If you have any questions before purchasing please email help@eeziflo.co.uk