WATERPROOF CLOTHING INFORMATION
What is waterproof?
Lots of clothes claim to be waterproof but what does that really mean?
Waterproofing usually comes with a number rating ending in MM. This refers to the hydrostatic head rating in millimetres.
If an item is rated at 10,000mm it can withstand the pressure of a 1mm diameter tube of water 10 meters (10,000mm) high before it lets water pass through.
Obviously for the average person on the street this means very little, so below is a rough estimate of were the numbers fall in general use.
This is just a guide as there are many factors that can change results, for instance, prolonged exposure to light rain in strong winds can have similar pressure to a heavy downpour.
Other things to consider are the type pf waterproofing, some clothes have coatings like DWR (Durable Water Repellancy) which causes the water to bead on the surface, this is a more affordable option that may need to be renewed over time after multiple washes, others have a waterproof membrane such as Gortex as a more physical barrier.
| 0-1,500mm | Water Repellent | Very Light Rain |
| 1,500 - 5,000mm | Waterproof | Light To Average Rain |
| 5,000 - 8,000mm | Very Waterproof | Moderate To Heavy Rain |
| 10,000 - 20,000mm | Highly Waterproof | Heavy Rain |