Long Term Report
Integral Designs eVENT South Col Bivy
Date: April 18th, 2004
Reviewer Information
Name: Jim Sabiston
Age: 50
Height: 6' 3" (1.9 m)
Weight: 207 lb (94 kg)
Girth at shoulders: 52” (132 cm)
Width at shoulders: 21” (53 cm)
Email address: JimSabis(at)aol(dot)com
State: New York
Country: USA
Backpacking Background:
I've been camping for several decades. I joined the Adirondack Mountain
Club four years ago, the Appalachian Mountain Club a year later and am active
in both. I have also expanded my backpacking to include more winter trips,
mountaineering and backcountry cross country skiing, and participated in the
AMC's Winter Mountaineering training program with Chauvin International
Climbing Guides. More recently, I have actively studied ways to backpack
lighter and more efficiently. During the summer months, my style tends toward
very light, but not quite ultralight. I use a hammock or tarp for warm weather,
and a small four-season tent for winter trips. Most of my other gear is very
changeable, as I am constantly experimenting with gear and techniques.
Product Information:
Manufacturer: Integral Designs
Year of Manufacture: 2003
URL: www.integraldesigns.com
Size: Long
Zipper: Left handed
Color: Yellow
Manufacturers Specifications:
Length: 92 in (2.34 m)
Width: 32 in (81 cm)
Girth: Shoulders: 69 in (175 cm)
Foot: 22 in (56 cm)
Weight (size Long): 22 oz (624 g)
Pack Size: 8 in X 5 in (20 cm X 13 cm)
Price: $245 US
Specifications as delivered:
Length: 92 in (2.34 m)
Width: 32 in (81 cm)
Girth: Shoulders :70 in (178 cm)
Foot: 24 in (61 cm)
Weight: Bivy = 22.5 oz (638 g)
Stuff sack = .75 oz (21 g)
Pack Size: 9 in X 5 in (23 cm X 13 cm)
A note regarding measurements: Determining the precise dimensions of a
fabric structure can be difficult. Soft fabrics constantly move and shift as
they are measured and pulled. With this in mind, I found the dimensions
provided by Integral Designs to be quite accurate.
Description of the Integral Designs eVENT South Col Bivy:
The Integral Designs eVENT South Col Bivy is a lightweight bivy shelter
intended for year-round use. The frills have been kept to a minimum to achieve
the lightest possible weight. The bivy is constructed using Integral Designs'
eVENT fabric throughout the upper, exposed panels. A proprietary fabric design,
eVENT is described as an improvement over the standard waterproof/breathable
polytetrafluoroethylene laminated fabrics (GORE-TEX being the best known). The
eVENT sections of the bivy are a bright, colorful, golden yellow. The bottom of
the bivy is made with a black, lightweight, urethane coated nylon. The bottom
of the bivy wraps up to meet the top panels, so all seams are above ground
level. All seams are finished with waterproof seam tape.
There are two zippers, one 23 inch (58 cm) black waterproof type, located
on the left side per my request, and a second zipper which runs across the
upper body of the bivy. Integral Designs offers the bivy with the side zipper
on either the right or left side, allowing the bivy zipper to line up with my
sleeping bag zipper. The upper zipper has three metal sliders which allow for a
variety of venting positions. This zipper is not waterproof. The top zipper
opening is offered some protection by a 6 in (15 cm) extension of the eVENT fabric
which forms a brim.
In an effort to provide some space over the bivy occupant's face, Integral
Designs has built in a wire hoop in the hood area. The wire is located inside a
narrow fabric tube which runs the full width of the bivy, starting and finishing
near the ends of the hood zipper.
Overall, materials and construction detailing appear to be of very good
quality.
A Preface to the Test Report:
Before I get into the substance of my report, a few comments on my test
focus are in order, as my goals may be a bit different from what most bivy
users might have in mind. My intent is to use the Integral Designs eVENT Bivy
as a core component of a three season backpacking/climbing overnight shelter
system. ‘Three season’ in this case means Fall/Winter/Spring. This is not an
unusual concept to 'light and fast' climbers, who often use a bivy as
minimalist shelter. I wanted all the advantages that the Integral Designs eVENT
Bivy had to offer (low weight, packs small, weather-proof but breathable) while
minimizing the inherent disadvantage that comes with a minimalist shelter of
this type (little space). My solution was a shelter system which uses readily
available, inexpensive and lightweight components: a tarp and a ground cloth.
The ground cloth serves several purposes. First, it provides protection for
the light, waterproof nylon bottom of the eVENT Bivy from rocks, sticks and
other ground debris. Second, by using an 'oversized' ground cloth
(approximately 6 ft X 6 ft (1.83 m X 1.83 m)), I have a place to spread out my
gear without having to lay it out in the snow, dirt, grass or, as is the case
on Fire Island, sand. I chose to use one of those heavy duty emergency blankets
readily available at most camping supply stores (not the flimsy silver type),
as it fit the application perfectly, is reasonably light and durable as well as
inexpensive. It has a reflective finish on one side, which should help reduce
heat loss in cold weather, and a bright red finish on the other side, which
should work nicely as an emergency signal device if needed. Oh yes, it can also
double as an emergency blanket!
I use a large 10 ft X 12 ft (3 m X 3.66 m) tarp for several reasons. First,
it provides lots of space. The tarp can actually act as a social center when
conditions require some shelter for cooking and socializing. Next, the larger
size also permits a greater variety of set up options, one of which provides
nearly the same level of protection as a tent.
For additional detailed information on this system, please refer to my Field Report
Long Term Field Experience:
The last four months of the test period have been a cold and moderately snowy
winter. As planned, I experimented with my lightweight shelter system, of which
the Integral Designs eVENT Bivy is the core element, to see how it would work
in freezing, snowy conditions. The big test came in late December, when two
friends and I made plans to climb Mount Marcy, located in the High Peaks
Wilderness of the Adirondacks and the highest point in New York State.
While my plan was to travel a light as possible, I elected to use a gear sled
for the ski in from the South Meadows trailhead. This allowed me to keep my
base camp gear confined and organized in the sled, while my climbing daypack
was effectively pre-packed and served as a towing harness for the haul into
Marcy Dam. The lightweight approach paid real dividends, as the gear sled,
fully loaded, weighed less than twenty pounds. It was by far the easiest tow
I’d ever done. The sled could easily be picked up with one hand and carried
without making any real effort! Each of my partner’s sleds required a lifting
crane to get out of the van! Chalk one up for the eVENT Bivy. As the bivy packs
very small, it also freed up an enormous amount of room on the sled, normally
dominated by my mountaineering tent. The result was a lightweight, low slung,
streamlined loaded sled which was a pleasure to tow. The resulting low center
of gravity also made the sled very stable, with no tendency to roll at all.
Setting up camp was a no fuss affair. As we anticipated snowfall, I pitched the
tarp between two trees, tying the ridge lines directly to the trees for
strength. The outer corners were set out with snow stakes. Inside, I spread out
the ground cloth, which had been used to wrap and cover the gear when stowed in
the sled, with the reflective side up. The eVENT bivy was then laid out on the
ground cloth and I inserted the sleeping pad, a full length Therm-a-Rest
Ultra-Lite, and sleeping bag inside. The entire process took about ten minutes
or so, quick and simple. Before turning in, I flatten out my Crazy Creek
folding camp chair and slip it inside the bivy and under the larger
self-inflating pad for a bit of extra, closed cell foam insulation.
The first night out was quite cold, dipping to -17 F (-27 C). Using my 0 F (-18
C) rated sleeping bag with a liner, I slept comfortably all night. I removed my
Arc’teryx Theta LT shell jacket and ski boots, but otherwise slept with all my
clothes on. The only heavy layer was an Arc’teryx Gamma AR fleece top. Under
this I wore a light Schoeller jacket, a light fleece Arc’teryx Delta Zip Tee
over a wicking tee shirt. The bivy seemed to extend the temperature range of
the sleeping bag a fair amount, as I was never cold, even with this relatively
light layering, but I do tend to run warm. A pee bottle break in the wee hours
went smoothly. I tried fiddling with different positions for the face zipper
again, but ultimately decided that almost fully open was best, as it would
accommodate proper venting regardless of which position I slept in. Ice
build-up proved to be an issue around the face opening where my breath
condensed on the inside of the bivy fabric. A considerable amount of ice
accumulated around the opening over the course of the night. Upon arising, I opened
the bivy and examined the inner surface. I found a very thin layer of light
frost over the inside of the bivy fabric, apparently frozen condensation, but
no sign of dampness or condensation elsewhere. There was no trace of dampness
on the surface of the sleeping bag. The morning temperature was -15 (-26 C).
After the day’s successful summit of Mount Marcy, I returned and examined the
interior of the bivy again. The light layer of frost was gone from the inner
body surface, but a good deal of the ice remained around the face opening. I
turned in at about 8:00 pm and temperatures were a relatively mild at 4 F (-16
C). The wind picked up and there was about an inch of snowfall during the
night. The tarp, which was left open at the ends, broke the main strength of
the wind. The bivy proved to be totally windproof. The open ends of the tarp
permitted some snow to drift in and I would occasionally get a bit of spindrift
blown onto my face through the face opening. This is the main disadvantage to
keeping the face opening as wide open as possible, but I found the sensation to
be rather pleasant. The next morning I awoke to find the bivy covered with a
very light dusting of powdery snow. This time, when I opened the bivy and
examined the inside surface, it was completely dry and free of any frost or
hint of condensation. The accumulated snow slid off easily. Packing up was
quick and easy, accomplished in about half the time as my partners. The tarp
and bivy combination was a snap to clean and pack, unlike my mountaineering
tent, which often had a layer of frost and ice built up on the inside of the
fly in these condition. My partners experienced a significant condensation
problem in their shared single wall, but non-breathable tent. They had to
actually chip off a thick layer of ice accumulation from the lower portion of
the inner walls.
As anticipated, the only disadvantage to the setup is the tarp and bivy does
not lend itself to lounging about in the way that a tent can, at least in deep
winter. A tent will accumulate a certain amount of warmth from body loading,
cooking, etc. Even a few degrees can make a surprising difference in ones
comfort level in winter. The tarp/bivy cannot retain this heat, due to the
open, well vented nature of the set up. It was always comfortable inside the
bivy, but one cannot really spread out in there! Of course, in more moderate
temperatures, this is no longer an issue. The tarp provides plenty of room and
shelter for cooking, but we retired to a nearby lean-to for most of our meal
preparations. We heated up water inside the main tent, which no doubt
contributed to the huge amount of condensation. The tarp/bivy combination never
presented a condensation problem, as the heated water vapor produced when
boiling water drifts harmlessly out of the shelter.
The eVENT Bivy, in combination with the tarp and ground cloth, has exceeded my
expectations as a winter shelter. But its real value to me is as a back-up
option for lean-to backpacking in the Catskills. The benefits of packing the eVENT
bivy are threefold. First, of course, I always have an emergency shelter with
me. Second, should the lean-to be occupied, I can bail and set up the tarp/bivy
and be quite comfortable and still protected from any foul weather that is
likely to come along, without having to lug a tent around. Third, given the
open nature of the lean-to, wind driven precipitation can sometimes make them
less than ideal shelters. Using the bivy in the lean-to goes a long way to
keeping me protected and comfortable when the weather is not cooperating. All
this with the added advantage of a smaller, lighter backpack!
Fig. 1: A cozy corner in the Catskill’s Mink Hollow Lean-to.
The Integral Design’s eVENT Bivy has held up very well to repeated use and
packing. The fabric appears to be softening somewhat (it was never very stiff)
but there is no evidence of wear to speak of aside from the inevitable dirt and
scuff marks. The zippers still work smoothly and the bottom fabric is in
excellent condition.
Summary:
The Integral Design’s eVENT Bivy’s strong point is supposed to be its
excellent breathability and my experience seems to support this. I have never
experienced any noticeable wetness inside the bivy, even in relatively warm and
humid conditions. The one instance of frost buildup probably illustrates that
there are conditions that simply override the ability of the fabric to breath.
When the fabric becomes cold enough, any moisture will freeze upon coming in
contact with it, just as it would on most any surface. I was favorably
impressed that this did not occur until the temperatures were far below
freezing. I should comment on a related point here. When packing, I noticed
that the sleeping bag seemed a bit heavier. I weighed it when I returned home
and found that the bag was 8 oz (227 g) heavier than normal. This was due to
moisture accumulating inside the bag’s down insulation. The bag returned to its
normal weight when it was allowed to dry out. This is mentioned simply to
illustrate that extreme cold will have a dramatic effect on how things
function. In this case, the dew point, the point at which airborne water
condenses, was somewhere inside the sleeping bag’s insulation. A large amount
of moisture was not even reaching the bivy surface. What little bit did make it,
simply froze on the inside surface, which would have been significantly colder
than the air inside it. This is no fault of the bivy as the same effect occurs
in a tent, but an effect of extremely cold weather, but one that any user
should be aware of. As the skin of the bivy ends up being the primary
transition point between the cold outside ambient temperature and the warm,
moist inside temperature, it is unavoidable that this happens.
The Integral Design’s eVENT Bivy has proven itself to be an extremely flexible
shelter in use. It has many advantages, notably its light weight, breathability
and small pack size that make it worth considering as a primary shelter as well
as an emergency shelter. As such it has become a permanent part of my
fall/winter/spring gear kit.
I would like to extend my thanks to Integral Designs for the opportunity to
test this very interesting product.
