How do we measure waterproof?
Imagine a really tall over 30 metre tube sitting on the fabric surface slowly being filled with water. As more and more water is added, the pressure on the fabric will increase. The level at which water starts to come through the fabric is the hydrostatic head, which is measured in mm. Transfer this procedure to an simple way, we clamp a part of the fabric down and jet a certain pressure of water stream to simulate that water column pressure.
WATERPROOF IS VARIABLE WHEN YOU WEAR
Water pressure comes from all sorts of bases from the obvious, speed and size of raindrops to backpack straps, climbing harnesses, even kneeling on the ground. These all exert water pressure on the fabric, for example, something like sitting on the ground, demand the fabric to have something along the lines of 1500 to 2000 mm, whereas kneeling in the same spot could exist something along the lines of 10,000 mm.
THINGS TO LOOK OUT FOR
Fabric care
Use a gentle laundry detergent or one formulated for waterproof clothing. Apply spray on waterproof enhance liquid after wash. more
DWR (Durable Water Repellent)
DWR is usually applied to exterior fabrics for extra waterproofing. It may become less effective over time, but it is still a useful feature to look for as it provides you with an extra level of pr... more
Seam sealing
When clothes are sewn together the needle makes tiny holes, which water could leak through. To stop this from happening the seams are “taped over” with waterproof tape. more