Thursday, November 23, 2006

"No Sweat"

Written about 20 May 2004:


"No Sweat" -- Making the Case for a High-Tech,
Lightweight, External Frame Pack.

To Sweat:
1. To excrete perspiration though the pores in the
skin; perspire.
2. To exude in droplets.
3. To condense atmospheric moisture.
4. To work long and hard.
5. To suffer much, as for a misdeed, such as, to
die from Hypothermia.

No Sweat: slang, easily done or handled.

[Source: Merriam-Webster Dictionary]


I have just re-read the BackPackingLight.com

"2004
Raingear Review and Gear Guide Overview".


When it first came out I was hot to buy the Haglofs LIM
Ultimate Jacket. At 8.8oz and only "$305(!)" it seemed
to be just what I wanted. However, it doesn't have a
2-way zipper and only received a 3.5 rating for
Ventilation Options. In the Field this jacket received
a 4 rating on Breathability and Ventilation. For me
that was like saying "a little sweat is OK". I
searched on and next read about the Montane eVent
Superfly Jacket at 15oz and only $350. This jacket
received an uninspiring 2.5 rating for Ventilation
Options. In the Field it did score better for
Breathability getting a 5, but also only received a 4
rating for Ventilation. The eVent fabric was said to
do an "admirable job" of compensating for the lack of
vents.

After reading the rest of the reviews I found that
most of the jackets, pull-overs and smocks had similar
"Breathability" and "Ventilation" concerns. Not bad,
just not as good as I had expected. I began to wonder
why all this high tech fabric and product engineering
wasn't working.

I went back to each review for clues; and soon I
knew what the answer was going to be. Now I had to
find a way to document my theory: that the pack or
packs used for this gear review were of the internal
frame/sleeping pad supported style. Whatever you
want to call this style of pack, they probably make up
95% of today's market in sales and are also very
popular with the "make-your-own" gear folks.

I myself own several high-end internal frame packs
but only use them for cold weather hiking. The smaller
of the two internal frame packs covers an area of
about 11" by 20" on my back. This is 220 square
inches; and when you include the shoulder straps and
hip belt you add another couple hundred square inches
for a total of about 460 square inches of Pack/Body
contact. I call this contact space the "Sweat Zone".

The Raingear review states "we stayed comfortable,
with moisture only building up underneath the pack and
its shoulder straps. Most of this was due to the
limited breathability of the pack and not of the eVent
fabric. ... the other areas where thermal and moisture
buildup occurred (behind head and front of chest) were
less relieved by opening the pit zips. We believe this
is due to the backpack's straps isolating these areas
from the pit zip ventilation, and not necessarily an
observation unique to the Mont-Bell Versalite Jacket."
These same or very similar comments were made for
several of the Raingear items reviewed.

My theory is that internal frame packs, as used in
the RainGear Review, are one of the biggest factors
keeping the High-Tech fabric from doing what it is
designed for. The "Sweat Zone" is reducing the
efficiency of this gear by a great deal.

It is time for a new High-Tech, Lightweight, External
Frame Design -- a design that truly creates an open
air space between your back and the pack. There are a
number of external frame designs on the market today
that claim to do this, but; but they don't really
succeed, and most are heavy. I have made several
external frames that push away from the waist area as
much as 4 inches. Two of these frames weigh 7oz and
9oz, respectively. My most recent frame, called the
SR7T1, was made from Titanium and Aluminum and has a
stripped weight of less than 7oz.

I would like to propose side-by-side tests of one or
more of the previously reviewed garments using both
the same style of pack as before as well as one of my
external frame packs. I predict that the test would
show a more favorable review for the raingear used
with the external frame pack than the test used with
the pack(s) from the original review.

The current "sweat zone" packs, so popular today,
create many handicaps. The High-Tech gear we have
available to us today can not overcome these
handicaps and work as designed. A new High-Tech,
Lightweight, External Frame Pack may be the answer.
_____________________________________

1 Comments:

Anonymous PhilipW said...

Your comments re the "sweat zone" created by most modern internal frame packs are very pertinent.

By way of offering some alternative thinking on modern pack design, this small NZ company has been pioneering some remarkable new packs.

http://www.aarnpacks.com/features/multifunction.html#vn

In particular the materials being used in the contact zone really are very breathable. The pack straps for instance offer almost no resistance to being "breathed" through, and the huge open mesh on the back panel really does work rather well in practise.

Monday, December 25, 2006 4:51:00 PM  

Post a Comment

<< Home