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.