How is Waterproof and Breathability Measured?
All outerwear material is rated making it easy to figure out which products are more waterproof and breathable than others. Traditionally material like oilskin and rubber have been used for waterproofing however these items do not breath and can become quite hot. Outwear technology has evolved to a point where your jacket and pants keep you dry without the issue of overheating. This is achieved by using material that has tiny holes too small to allow water molecules past but large enough to let water vapor through. Some material does this much better than others and a rating system has been created to help customers figure out just how waterproof and breathable their outerwear is.
Waterproofing is measured by the amount of water in millimeters, that can be suspended above the fabric before it seeps through. This is usually done using a narrow cylindrical tube. Material that is considered to be waterproof must have a rating of at least 1,000mm. The majority of outerwear sold for Australian conditions sits at about 5,000mm. To put it into perspective the best material goes up to about 20,000mm. Gore-Tex is the best but it does not carry a rating however many companies claim it sits anywhere inbetween 25,000mm to 40,000mm. While 5,000mm is great for Australian conditions if you plan on sitting in the snow a lot you might want to grab a pair of pants with 8,000-10,000mm. Unfortunately there is no universal base of measurement and the size of the cylindrical tube and temperature during the test can vary. This means 10,000mm waterproof rating on one company's jacket can vary from another company. Often you can tell the difference when you feel the actual fabric. Thick sturdy fabric is going to be more waterproof than thin fabric that feels like paper even when they are both 10,000mm rated. If waterproofing is a big concern for you make sure you always go as high as possible.
Most snow fabric is coated with a waterproof spray that can wear off over time. The waterproofing can be reapplied and we usually recommend doing this at the beginning of every season. We also recomend washing your outerwear with specific outerwear detergent. Outerwear fabric has tiny microscopic fibers that stick up and help water to bead and roll off. When the jacket gets dirty these fibers get pushed down and aren't as effective. If you don't use the correct type of detergent then the fibers can get damaged or rip off.
Breathability is measured by the rate at which water vapor passes through a square meter of fabric over a 24 hour period. This is most often measured in grams. Like waterproof ratings, breathable material starts at 1,000g and the highest rated material goes up to 40,000g. Much like Waterproof ratings the breathability rating is not universal. Thankfully most of the outerwear we carry has ventilation features so even if the outerwear isn't as breathable you can still easily cool down by zipping open a vent or opening your jacket.