250mm Class 12 PVC pressure pipe for irrigation, water supply and general water transfer. Manufactured from rigid, unplasticised PVC (PVC-U) to AS/NZS 1477.
The 250mm measurement is the nominal pipe size used to select matching pressure fittings. The pipe has an approximate outside diameter of 280.4mm, internal diameter of 252.9mm and wall thickness of 13.8mm. Nominal size is a size designation, not the measured bore or outside diameter.
Class 12, also called PN12, has a nominal working pressure rating of 1200kPa 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.
Select the jointing method and fittings to suit the pipe supplied. Solvent weld joints use priming fluid and pressure-rated solvent cement; Type P is used for standard interference-fit pressure joints. Rubber ring joints use the specified sealing ring and lubricant. Follow the manufacturer’s jointing instructions, including curing times for solvent weld joints, 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.
