The two figures you will meet most often in HDPE pipe catalogues are SDR and PN. Understanding them is the key to choosing the right pipe.
SDR — standard dimension ratio
SDR is the ratio of a pipe's outside diameter to its wall thickness: SDR = D / e. The lower the SDR, the thicker the wall and the higher the pressure rating.
PN — nominal pressure
PN is the working pressure (bar) a pipe can carry continuously for 50 years at 20°C. For PE100:
| SDR | PN (PE100) |
|---|---|
| 26 | 6 bar |
| 17 | 10 bar |
| 11 | 16 bar |
| 7.4 | 25 bar |
MOP for gas pipes
Gas lines use MOP (maximum operating pressure) instead of PN, with a higher safety factor.
How to choose
Consider operating pressure, temperature, surge risk and installation method. When in doubt, talk to our engineers.
