another quote from david lesh on the First Drop Outerwear Thread -
Its really too bad that there is such a large misconception about millimeters of water-proofing and breathability.
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
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.
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.
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.
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
Other things that play a big role are fabric material, construction, various coatings, seam seals and tape, lining, etc.
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
- quite a statement.