Imperial pipe is measured and classified as an inside diameter. This is unlike metric PVC pipe that is measured as an outside diameter. AS an example a 50mm metric PVC pipe will measure 50 mm on the outside of the pipe. If you convert this to inches then one would assume that this would convert to a 2" imperial pipe. This is incorrect as a 2" imperial PVC pipe will measure 2 inches on the inside and will have an outside diameter of 61 mm.
Normally most people on a new installation will instal metric PVC pipe however many existing installations like swimming pools, Hot tubs, old factories etc will have an imperial PVC pipe installed and these may from time to time need repairing.
Before you start ordering your fittings please measure the outside diameter of your PVC pipe in mm's. This must be accurate as a 2mm error could lead you to buy imperial fittings rather then metric. AS an example a 2" imperial PVC pipe will measure 61mm outside diameter while the metric equivalent will measure 63mm.
Please compare the outside diameter to the table below so that you can choose the correct size fitting for your repair. If installing a new system then please refer to the metric equivalent as this will be cheaper and far more accessible
Outside Diameter in mm's |
True Size | Action To Take |
---|---|---|
20 mm | 20mm Metric | |
21 mm | 1/2" Imperial | Choose fittings from list below |
25 mm | 25 mm metric | Click here for 25mm |
26.5 mm | 3/4" imperial | Choose fittings from list below |
32 mm | 32 mm Metric | Click here for 32 mm metric |
33 mm | 1" Imperial | Choose fittings from list below |
40 mm | 40 mm metric | Click here for 40 mm metric |
42 mm | 11/4" Imperial | Choose from fittings below |
47.5 mm | 11/2" Imperial | Choose from fittings below |
50 mm | 50 mm Metric | Click here for 50 mm metric |
61 mm | 2" Imperial | Choose from fittings below |
63 mm | 63 mm Metric | Click here for 63 mm Metric |