Waterproof & Breathability

The Science of Waterproof Breathable Technologies

The science of Waterproof/Breathable fabric technology

The largest organ on or in the human body is the skin. While this amazing organ is well adapted to regulating our body’s temperature, things can get a bit tricky when layers of clothing are introduced. The reason for this is because our skin is constantly producing moisture to one degree or another depending on the conditions and the person. It would be simple enough to keep water from outside our gear from getting in - you could just grab a trash bag if you want - but what about allowing the skin to breath and to maintain relatively normal breathability?

Here at Obermeyer finding technologies that can perform at high levels during activity is just as important to us as making sure that same gear can take care of the person wearing it. We measure the performance of our fabrics in conjunction with a third-party testing facility called SGS Testing Laboratories. The good people at SGS go to great lengths to verify our performance results and ensure  consistent performance throughout our technical lineup.

But what do all these numbers mean and how does that affect you? Let’s take 10/10K for example. What does it mean? These numbers are a standardized testing method which indexes performance. The first number is measured in millimeters (mm) and is a measure of water-proofness. With a 10K or 10,000mm fabric, we would put a square tube with inner dimensions of 1” by 1” over a piece of shell fabric, you would be able to fill it with water to a height of 10,000 mm or 32 feet before water penetrates the fabric. Once a tester can see two drops of water penetrate, then that is the point of measurement; the higher the mm on a fabric, the higher the waterproofness.

The second number relates to the breathability of a fabric. This performance index is taken by measuring how many grams (g) of water vapor pass through a square meter of fabric in a 24-hour period. The goal is to mimic a user’s body and is taken from the inside of the fabric to the outside. So a 30K fabric would allow 30,000 grams of water vapor to pass from the inside to outside in a 24-hour period.

The most important aspect of waterproof/breathable fabrics is keeping the body dry by acting just as the skin would on its own. The human body cools down much quicker when wet so staying dry equals staying comfortable.