We came across this in a Sprinkler report for New Zealand. It also mentioned
- OH1 Ordinary Hazard type 1
- OH2 Ordinary Hazard type 2
- OH3 Ordinary Hazard type 3
- EHH Extra High Hazard
- LH Light Hazard
We also came across this article from Australian Building Services which stated:
The type of sprinkler system to be installed will depend on the hazard classification of the building according to the NCC (National Construction Code).
The 3 main hazard classifications are :
- Light Hazard
- Ordinary (OH1 – OH3)
- High Hazard
The main difference between the 3 categories is the volumes of water and storage required increases with the hazard classifications. i.e High Hazard required more water, in higher quantities in a shorter time.