TECHNOLOGY

WATERPROOFNESS & BREATHABILITY

The waterproof/breathability of fabrics is typically describes with two numbers.

The first is in millimeter (mm) and is a measure of how waterproof a fabric is. In the case of a 20k or 20,000mm fabric, if you put a square tube with inner dimension of 1”x1” over a piece of said fabric, you can fill it with water to a height of 10,000mm before water would begin to leak through. The higher the number, the more waterproof the fabric.

The second number is a measure of how breathable the fabric is, it’s normally expressed in terms of how many grams of water vapor can pass through a square meter of the fabric from the inside to the outside in a period of 24b hours. In the case of a 20k fabric, this would be 20,000 grams. The larger the number, the more breathable the fabric.

WATERPROOF RATING

Waterproof rating (mm) Resistance provided 0-5,000 No resistance to some resistance to moisture

6,000-10,000 Rainproof and waterproof under light pressure What is can withstand Light rain, dry snow, no pressure Light rain, average snow, light pressure

11,000-15,000 Rainproof and waterproof except under high pressure Moderate rain, average snow, light pressure

16,000-20,000 Rainproof and waterproof under high pressure Heavy rain, wet snow, some pressure

20,000 + Rainproof and waterproof under very high pressure Heavy rain, wet snow, high pressure