I saw someone post this, and i though it was pretty good.
Its really too bad that there is such a large misconception about
millimeters of water-proofing and breathability. That rating system is
a total scam, and people really end up playing into a huge marketing
scheme of companies all trying to outdo each other with tech talk.Do
you even know how they get those numbers? Well, they take a swatch of
fabric, turn it upside down (outside face down) and clamp it to a bowl.
The bottom of the bowl has a tube, which runs up to a bucket that is
filled with water. That bucket is then raised into the air, and the
height (in millimeters) that the bucket gets to when water is forced
through the fabric is the mm of waterproofing.So, even from the
beginning of the test, the fabric is not only completely saturated with
water, but then the increasing pressure of the raising bucket adds many
times the force of gravity to the already completely saturated fabric.
Any fabric that can even withstand the beginning of this test (zero to
a few hundred mm) is a great fabric.In the real world, there is no
force that puts this much water pressure on a fabric, this only happens
in the lab. Because of this, any fabric over a few hundred mm of
waterproofing is going WAY above what is necessary for forces of water
found in the real world. Plus, the higher the mm of waterproofing, the
less breathable the fabric usually can be.Generally, the fabrics that
are above a few thousand mm waterproof tend to be woven more tightly,
and therefor are generally thinner, more technical fabrics. You end up
losing a lot of thickness and durability because of this. When your 20k
mm jacket gets a hole in it, it's not very water proof anymore!Other
things that play a big role are fabric material, construction, various
coatings, seam seals and tape, lining, etc.Because of all of these
factors, First Drop has specifically chosen the fabric with
waterproofing, breathability, and durability in mind. We feel it is the
best fabric for our purposes, and we have personally tested the suits
in full winter blizzards and rainstorms this year. They preformed
flawlessly.