Choosing a suitable water column rating

 

This table will give you an idea of the ratings suitable for different uses.

 

Water column	Conditions
3,000 mm	Light rainfall, dry snow, no pressure.
5,000 mm	Light rainfall, snowfall, light pressure.
10,000 mm	Normal rainfall, snowfall, medium pressure.
15,000 mm	Heavy rainfall, wet snow, high pressure.
20,000 mm and above	Heavy rainfall, wet snow, very high pressure.