When you purchase a brand-spankin’ new outerwear kit, odds are you’re thinking to yourself, “Damn, I’m gonna look fine on the slopes.” That personal expression of style is a key element of making skiing fun and exciting, no doubt, but outerwear is also packed with technology to keep you safe from the elements, and it’s important not to overlook the technical aspects of your apparel. The complexities of outerwear are, well, complex… so, we’ve outlined the most noteworthy terms and construction nuances to ensure your next big purchase is one you won’t regret.
How a Membrane Works
The key ingredient in the outerwear pie is the membrane (below). It must be protective and permeable, a certified catch 22. A top-notch membrane has minuscule holes small enough to block invading water droplets but big enough to free escaping vapor molecules. How is this possible, you ask? Consider that in some cases, one square inch of your membrane is home to more than nine billion pores.
Durable Water Repellent
While the membrane of a garment is waterproof, its face fabric is not. The membrane is useless if the outer layer is drenched with moisture, so, a durable water repellent (DWR) coating is applied to the outer layer to prevent the advance of water.
Insulated outerwear is pumped full of down—the warm, inner layer of feathers on a bird—or a synthetic insulator for increased warmth. Generally, manufacturers employ heavier insulation in areas like the torso and hood, which are susceptible to heat loss. Down’s “fill power” gauges its warmth. The number is a result of a test where one ounce of down is stuffed into a graduated cylinder. The volume it occupies, in cubic inches, is its fill power. The higher the number, the better it insulates—with numbers generally ranging from 500 to 800. Down’s impressive warmth-to-weight ratio and compressibility make it particularly attractive.
Synthetic insulation is comprised of ultra-thin polyester fibers. While not quite as warm and compressible as down, synthetics are generally superior when it comes to repelling water. The weight of a one-meter-by-one-meter sampling of synthetic insulation makes up its rating. A higher weight translates to more warmth, with weights generally ranging from 40 to 120 grams.
Two Layer vs. Three Layer Construction
The terms two-layer (2L) and three-layer (3L) refer to a garment’s membrane and protective layers. The initial layer of waterproof/breathable outerwear is the membrane (read more above). The membrane is bonded to one or two other layers that keep it from being damaged.
The “face fabric”—usually made of nylon or polyester—is the outermost layer of your garments; it safeguards the membrane from deterioration as well as dirt. Your garments’ colors and prints are associated with the face fabric.
In two-layer apparel (see below left), the membrane and face fabric are bonded together and a sewn-in liner on the inside further protects the membrane from wear and tear. Insulation is sometimes packed into the liner, yielding warmth. Two-layer construction is suitable for most conditions you’ll encounter on the ski hill.
Three-layer outerwear (see above right) utilizes a membrane that’s sandwiched between the face fabric and a moisture-wicking, breathable inner layer that provides a cool-down during intense exercise or warm weather scenarios. Three-layer shells offer incredible protection against severe weather where moisture and wind abound.
Seam Taping & Welding
In the process of sewing together outerwear, needle holes pierce through the membrane around the seams and zipper. These holes can allow water to seep into your clothing, thus ruining your otherwise perfect ski day. Major. Bummer. In turn, seams are taped over to cover the holes, or in more premium offerings, welded in a process called seam sealing.
In some cases, only the areas most prone to soaking are sealed or taped. This is called “strategic” or “critical” sealing (above right), which is reliable for all but the wettest and snowiest of ski days. Fully sealed seams (above left), however, stand up to the most extreme conditions you’ll face.
Waterproofing & Breathability Ratings
The waterproof ratings you’ll see on the following pages are determined via a water column test. A one-inch square tube is positioned on top of a piece of fabric and is then filled with water until the liquid penetrates the membrane. The amount, in millimeters, that the fabric resists before the proverbial flood gates open is its rating, e.g., 15,000 mm or 15K. The higher the number, the more waterproof the garment.
The breathability rating is derived from a test that measures the amount of water vapor that can pass through a square meter of fabric or membrane over the course of 24 hours. The results are measured in grams per meter squared per day (15,000 g/m2/d would be a 15K rating). Here, too, the higher the number, the better the breathability. Waterproofing and breathability ratings are often displayed together. E.g. 15K/15K, 20K/20K, etc.