KIT & GEAR
TECHNICAL FABRIC MAINTENANCE
micro-climate inside your clothing system helps to prevent
either too. The body regulates itself effectively; as activity
levels increase you sweat and the evaporation of this
moisture helps to cool the skin. If moisture is not allowed
to move away you will become “uncomfortable” inside
your clothing system.
Letting moisture escape from the system is a tricky
thing but it’s essentially what is being discussed when
we use the word “breathable”. Behind it all is a law of
nature: the Law of Partial Pressures. This law states that
moisture as a vapour will naturally move from a warm,
high pressure environment to a cooler low pressure one.
If we are keeping a well-balanced temperature inside our
clothing system, then on a bad-weather day moisture
will move away from our skin through the pores in our
clothing and escape to the outside. Sometimes we call
this the “Temperature Gradient” as it sounds like moisture
vapour is moving “down” from hot to cold.
So does a breathable fabric technology work in a rain
forest? Yes, is the answer but due to the temperature
inside the garment and outside the garment being more
in equilibrium, the transfer rate will obviously slow down.
We all know we can work with Ma Nature - but never
beat her!
This, of course, is also subject to testing. Many
methods can be used here to establish a Moisture Vapour
Transmission Rate (MVTR) or a Resistance to Evaporative
Transmission (RET) figure. Of the two I prefer an RET figure
as it just plain makes more sense to me. Skin is 100%
breathable and has an RET of Zero. As soon as you cover
it though, you build up a resistance that slows down
the rate at which moisture can be transmitted away; the
thicker the barrier the more resistance and the slower the
transmission. In essence, this means that as you cover the
skin with layers your system becomes less breathable so
we will always be looking for technical fabrics with as low
an RET figure as possible.
In some cases the clever folks at Gore have got the
RET figure well down into single figures, especially on
their bespoke technologies. They continually develop
completely new and innovative lining fabrics which are
thinner (but more durable) than the industry standard
linings available elsewhere - and thinner = less resistance,
right?
WHAT YOU CAN DO IN YOUR DOWNTIME
If you’re spending a lot of money on a set of waterproof
gear, then you really want to get the best out of it don’t
you? Just like changing tyres or the oil in a car, your “shell
gear” will really, really benefit from some regular “TLC”, a
bit of a service if you like. I truly believe that there is a far
better understanding of the fabric technology used in our
clothing systems than ever before and it’s a subject that is
a bit of a “holy grail” for me. All too often I’m out on the
range or at a game with my mates and when we get back
in the car their “Gucci” waterproof shell gear just gets
dumped unceremoniously in a pile on the floor or in the
footwell!
These are usually the self-same people that I will see
at a later date bemoaning the fact that their expensive
waterproof jacket “isn’t working”, complaining to all
and sundry that somehow the technology has failed and
that they are wet and uncomfortable. The most common
gripe I hear is that “this funking thing is leaking” when
actually it’s still perfectly fine and the fact is, it just isn’t
“breathing” anymore!
Like all performance items, top-end shell gear needs
maintaining regularly to get the best from it. You might
only change the tyres on your car infrequently (probably
when the MOT or insurance inspection rolls around!),
but on a Formula One car they may change the tyres
several times during a single race to get the very best
performance.
When you buy a Gore-Tex (or similar) jacket you’re
investing in a high-performance item, and as such,
it needs treating like one! Over time things like the
hydrophobic (water-heating) Durable Water Repellent
(DWR, think a microscopic “film”) on the outer face fabric
of the garment will begin to wear and crack and the fabric
will start to hold the water that’s now allowed through to
it. As new, water droplets will be held on the DWR layer,
simply rolling off the fabric before they penetrate. You’ll
notice after a while that this “beading” process will start
to lessen and that the water is being absorbed into the
fabric itself; this is usually noticeable first in areas like the
shoulders where pack straps or a plate carrier rub and
abrade the DWR, or on cuff ends where the fabric rubs
against itself.
Internally over time, body oils, grease and general dirt
will also build up and the net result is that your jacket
will stop “breathing” as well as it did when it was new.
You won’t really notice this until it becomes obvious and
water vapour that was previously being transferred out of
the system stays inside and re-condenses. You’ll feel cold,
clammy and uncomfortable and, when you put your hand
inside your jacket, feel “water” and of course your quite
natural conclusion will be that the jacket is leaking!
A re-proofer will restore the waterproof performance
of your gear to ensure it continues to keep you dry and
protected. To combat the degradation of performance you
simply need to give your jacket (or pant) a bit of care and
invest in a maintenance product. There are many of them
“IF YOU WERE TO SIT ON A WET, FLAT SURFACE THE MEAN PRESSURE YOU GENERATE IS AROUND
10,000MM! IF YOU WERE KNEELING IN A FIRING POSITION THEN THE POINT OF THE KNEE GENERATES
15-17,000MM OF PRESSURE…”
48
MAY 2020