Explaining The Waterproof Ratings

Breathability, DWR, Waterproof -

Explaining The Waterproof Ratings

Here is a breakdown of what a waterproof rating is, and what breathability is. If you like snow, there is a good chance you want to stay warm. Remaining dry is also high on the agenda.

There are so many options out there these days; it’s hard to keep up. But here we will try our best to simplify it:

WATERPROOF RATINGS

5K

Water Resistance Provided: Some resistance to moisture.

Conditions: Very light rain for short periods, dry snow

6k to 9K

Water Resistance Provided: Waterproof under light rain

Conditions: Very light rain for short periods, average snow, light pressure.

10K to 14K

Water Resistance Provided: Rainproof and waterproof except under heavy rain.

Conditions: Moderate rain for short periods, average snow.

15K to 19K

Water Resistance Provided: Rainproof and waterproof under heavy conditions.

Conditions: Heavy rain for medium periods, wet snow.

20K +

Water Resistance Provided: Rainproof and waterproof under very high conditions.

Conditions: Heavy rain for extended periods, wet snow.

SURE THE NUMBERS WERE GOOD, BUT LET’S DIVE IN

Our manufacturers test all our fabrics. And trust us, we do all out testing on the slopes and also at Après. Always good to see how they perform in all kinds of wet conditions! The numbers tell you how waterproof and breathable the fabric is.

Let’s take a rating of 15k. You can try this at home if you want. If you put a square tube with inner dimensions of one-inch x one inch over a piece of 15k fabric, you could fill it with water to a height of 15,000 mm (15 meters or 49.2 feet) before water would start to pass through the fabric. The higher the number, the more waterproof the fabric and the bigger tube you will need. Above, we explained the pressure. If the rain is coming down hard and fast and constantly hitting your garment, there is a limit. The longer and harder this comes down the shorter the garment will withstand. That’s why we won’t use anything below 15K.

You might be asking yourself about the breathability by now. It’s expressed in grams. To break it down, it’s how many grams (g) of water (which in this case will be vapour, AKA sweat) can pass through the garment from the inside during a 24hour period. The inner layer has what’s called a membrane. It has tiny holes too small to let liquid water out, but just big enough to allow vapour to escape. The only way to create vapour is via sweat, and the vapour will pass through the garment.

In the case of a 15k (15,000 g) fabric, this would be 15,000 grams. The larger the number, the more breathable the fabric. Our testing led us to start at 15K for breathability.

WHAT ABOUT A COMPLETELY WATERPROOF JACKET?

It’s possible, but you would have to wear a rubber coat with zero breathability. The result would be you sweating it up on the inside, no ability to let your body breathe, and you would turn yourself into a sauna. Use a rubber raincoat for when it downpours on land. Not on the mountain. The clue here is to balance the waterproof with the breathability depending on what the mountain is going to throw at you. Always a good option to go with a shell jacket with no insulation and work on your layers. 


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