Water Resistance and Breathability Ratings
Gore-tex Isn't Waterproof!
Water Resistence and Breathability Ratings
Gore-Tex Isn’t Waterproof!
Water-Resistant Ratings
The waterproof rating of specific materials are tested in a lab. Researchers test the fabric’s waterproofness by measuring water resistance to pressurized water on a particular fabric. Higher ratings equal more water-resistance.
The ratings are measured in two ways: millimeters per 24 hours and pounds per square inch (psi).For example, one type of water resistant material called Gore-Tex has a waterproof rating of 28,000 mm (sometimes written as 28 K) and 40 psi.
This material can withstand 28,000 millimeters of water in 24 hours (also seen as 40 pounds of pressure per square inch) before it leaks through. The conversion for PSI to mm is: 1 PSI = 704 mm.
Testing for waterproofness is not standardized across the board but the ratings can help you decide which performance shell to purchase based on your specific needs. Click here to view our simplified water-resistance rating guide and other outer-layer purchasing hints.
Breathability Ratings
The breathability rating, measured in grams, is tested in a lab. It is tested by the amount of water vapor that exits one square meter of fabric in 24 hours. Higher ratings equal more breathability. This rating is usually expressed after the water resistance rating.
An example would be 15K/20K.This rating tells us that this particular garment can withstand 15,000 millimeters of water in 24 hours (waterproofness) and 20,000 grams of water vapor will escape through the material in 24 hours (breathability).
Like waterproofness, breathability is not standardized across the board but the ratings can help you decide which performance shell to purchase based on your specific needs. Click here to view our simplified breathability-rating guide and other outer-layer purchasing hints.
Check out our waterproofness & breathability chart below. We listed all the available ratings we could find from various companies and their associated brands.
“I refer to this chart anytime I’m looking to buy a new shell for myself or while looking at shells to recommend for others.” – Rob
