25mm Class 9 PVC pressure pipe for irrigation, water supply and general water transfer. Manufactured from rigid, unplasticised PVC (PVC-U) to AS/NZS 1477.
The 25mm measurement is the nominal pipe size used to select matching pressure fittings. The pipe has an approximate outside diameter of 33.6mm, internal diameter of 30.5mm and wall thickness of 1.6mm. Nominal size is a size designation, not the measured bore or outside diameter.
Class 9, also called PN9, has a nominal working pressure rating of 900kPa at 20°C. The allowable working pressure reduces as the pipe temperature rises above 20°C. Select the pipe class to accommodate the system pressure, including pressure surges, and use fittings with a suitable pressure rating.
The pipe is joined to compatible 25mm PVC pressure fittings using priming fluid and pressure-rated solvent cement. For standard interference-fit pressure joints, use Type P solvent cement. Solvent welding softens and bonds the mating PVC surfaces to form a permanent joint. Cut the pipe square, remove burrs, clean and prime the joint surfaces, then allow the joint to cure for the time specified by the cement manufacturer before pressurising.
The smooth internal surface helps limit friction losses as water passes through the pipe. Flow capacity depends on the internal diameter, pipe length, fittings and available pressure.
For buried installations, use suitable bedding and backfill to support the pipe and keep sharp stones away from its wall. Above ground, support the pipe along its length and allow for movement as its temperature changes. Follow the manufacturer’s installation guide for the site conditions.
PVC pressure pipe dimensions
Approximate dimensions in mm.
| Nominal size |
Outside diameter |
Class 9 / PN9 | Class 12 / PN12 | Class 18 / PN18 | |||
|---|---|---|---|---|---|---|---|
| Internal diameter |
Wall thickness |
Internal diameter |
Wall thickness |
Internal diameter |
Wall thickness |
||
| 15 | 21.4 | - | - | - | - | 17.8 | 1.8 |
| 20 | 26.8 | - | - | 23.7 | 1.6 | 22.4 | 2.2 |
| 25 | 33.6 | 30.5 | 1.6 | 29.8 | 1.9 | 28.1 | 2.8 |
| 32 | 42.3 | 38.5 | 1.9 | 37.5 | 2.4 | 35.4 | 3.5 |
| 40 | 48.3 | 44.1 | 2.1 | 42.8 | 2.8 | 40.5 | 3.9 |
| 50 | 60.4 | 55.2 | 2.6 | 53.7 | 3.4 | 50.5 | 5.0 |
| 65 | 75.4 | 68.9 | 3.3 | 67.0 | 4.2 | 63.2 | 6.1 |
| 80 | 88.9 | 81.3 | 3.8 | 79.0 | 5.0 | 74.6 | 7.2 |
| 100 | 114.3 | 104.6 | 4.9 | 101.7 | 6.3 | 96.0 | 9.2 |
| 125 | 140.2 | 128.4 | 5.9 | 124.9 | 7.7 | 117.6 | 11.3 |
| 150 | 160.3 | 146.8 | 6.7 | 142.6 | 8.8 | 134.7 | 12.8 |
| 155* | 168.2 | 154.2 | 7.0 | 149.2 | 9.5 | - | - |
| 200 | 225.3 | 208.5 | 8.4 | 203.1 | 11.1 | 192.9 | 16.2 |
| 225 | 250.4 | 231.7 | 9.3 | 225.8 | 12.3 | 214.4 | 18.0 |
| 250 | 280.4 | 259.4 | 10.5 | 252.9 | 13.8 | 239.9 | 20.2 |
| 300 | 315.5 | 292.0 | 11.8 | 284.5 | 15.5 | 270.2 | 22.7 |
*155mm is a specialised borecasing size used to line water bores. It requires fittings matched to its 168.2mm outside diameter; standard 150mm pressure fittings do not fit.
Actual dimensions may vary within manufacturing tolerances. This table is a dimension reference; select available sizes and classes from the product range.
