Initial Report | Field
Report | Long-Term Report |
Height: 6 ft (183 cm)
Weight: 170 lb (77 kg)
Email: (willi_wabbit at
bresnan dot net)
City & State: Durango, CO
Location for Testing: Southwestern
US (Colorado, Utah, Arizona, New Mexico).
have been an avid backpacker for 50 years. Backpacking is my
passion. I backpack the year around in the Southwestern United States
(Colorado, Utah, Arizona, and New Mexico).
Backpacking Style—I have
been a lightweight backpacker for 35 years and an ultralight backpacker
for 9 years. My wife and I give presentations on lightweight and
ultralight backpacking in our local area, and have developed a website
called Southwest Ultralight Backpacking (http://home.bresnan.net/~swultralight/)
to share information.
(March 3, 2008)
Product Information (photo)
Manufacturer Website: http://integraldesigns.com/
Product Tested: Penguin Reflexion Bivy
Year of Manufacture: 2008
Size Tested: One size
Length and Girth: Length 84
in (213 cm), chest girth 76 in (193 cm), hip girth: 64 in (163 cm), foot
girth 42 in (107 cm)
Fit Range: Fits to 6 ft 4 in
Packed size: 3 in x 3 in x 14
in (8 x 8 x 36 cm)
Weight: Measured weight 22.3
oz (632 g); manufacturer weight 23 oz (650 g)
MSRP: $265 US
The Integral Designs
Penguin Reflexion Bivy is made of SympaTex Reflexion fabric,
which has a thin aluminum layer (bonded to its membrane) that is
claimed to reflect back 75% of body heat. (Photo from Integral
is unique about the Integral
Designs Penguin Reflexion Bivy is that it is made entirely
of SympaTex Reflexion,
a waterproof-breathable 3-layer fabric that contains a thin aluminum
layer that reflects body heat back to the sleeper. The bivy is claimed
to add dramatically to the warmth of a sleeping system. According to the
fabric manufacturer (SympaTex), the Reflexion fabric reflects as much as
infrared rays (heat that the body gives off) back to
the body. Because
of its heat retaining technology, the Penguin Reflexion Bivy is intended
for winter and high altitude use, and for use as a rescue bivy.
The Penguin is designed as a standard bivy; it does not use any poles or
hoops to hold the bivy above the face. Rather it has a stiffened shape
to lift the bivy above the sleeper's face.
from the Integral Designs website and hang tags on the bivy)
SympaTex Reflexion fabric has a waterproof/breathable inner membrane
with a thin aluminum coating that reflects back body heat
seams are seam taped on the inside
center ˝ length (48 in/122 cm) waterproof zipper with three sliders
face vent keeps fabric away from the face
vent behind the head
stake loops at top corners
The Penguin is a serious mountaineering bivy constructed
of a durable 3-layer (face fabric, membrane, lining fabric) waterproof/breathable fabric (SympaTex Reflexion) that has
the unique characteristic of reflecting back body heat to keep a sleeper
I did some internet research for a
description of SympaTex
Reflexion fabric, and found some good information in the Wikipedia. The
unique heat reflecting technology in Reflexion fabric is accomplished by
condensing aluminum vapor on the the fabric's membrane, creating an
aluminum layer only a few micrometers thick sandwiched between its membrane and lining fabric, which reflects much of the radiated heat from the human body to preserve the user’s warmth.
SympaTex membrane is made of a hydrophilic
polyether-ester copolymer, which has no pores, and can be referred to as a monolithic
membrane. It functions similar to the common polyurethane
membrane, i.e. no
water can get in from the outside, but water vapor transport from the inside to the outside
through the membrane is by way
of an absorption and evaporation processes (vapor to liquid to vapor) . This
sluggish moisture transfer
through the membrane is what is referred to as "breatheability".
A closed membrane like SympaTex is much less efficient compared to microporous membranes (such
which have microscopic pores that let air and water vapor pass
through, yet have such low surface energy that the surface tension of
any liquid water in contact remains too high to allow it to squeeze
through the pores.
Interestingly, there are no instructions included on how to best use the
bivy, other than to use the bivy on top of a pad to protect the fabric
and to leave an opening in the zipper to ensure proper ventilation. I
presume that the user would want to breathe outside air through a
breathing hole in the zipper, rather than exhale into the bivy, which
would cause carbon dioxide and moisture buildup inside the bivy. The
purpose of the tunnel vent behind the head is not stated, but it’s
apparently provided to ensure an air supply should the user decide to
breathe inside the bivy.
Assessment So Far
Materials and Construction—
Although the weight of the SympaTex Reflexion fabric
is not provided, it is about the same as a typical 3-layer eVENT or
Gore-Tex fabric used in shell jackets, which is around 2.5 oz/yd2
(85 g/m2). A 3-layer fabric is a
sandwich of a face fabric, membrane, and inner lining.
While the Penguin Reflexion Bivy is not ultralight at 22.3 ounces (632
g), it is not as heavy as some bivys that include poles to expand the
head area. To raise the bivy above the face, the Penguin incorporates
panels of shaped stiffer fabric that expand the bivy out so the fabric
does not lie on the sleeper’s face. Its waterproof zipper has three
sliders so a breathing hole can be placed in the desired spot.
The bivy’s construction is excellent, with even tight stitching
throughout and neat taping of all seams on the inside.
Size and Fit—The
Penguin bivy is over-sized so it will fit over virtually any sleeping
bag. The chest girth is 76 in (193 cm), which is about 10-12 in (25-31
cm) more than the girth of a typical 10-15 F (-12 to -9 C) sleeping bag.
I inserted a size long down sleeping bag rated at -10 F (-23 C) into the
bivy and it accommodated it with a little room to spare. From this I
conclude that the Penguin is sized so it will fit over a size long
sleeping bag rated for extremely cold temperatures (-20 F/-29 C or
below) without compressing the down.
Report (May 13, 2008)
During the first two months of testing I slept in the Penguin Bivy on
five trips totaling 13 nights, summarized as follows:
Winter Camp in
Winter Camp in
Winter Camp in
Shortly after receiving the Penguin Bivy for testing, I took it on two
igloo camping trips. The first was for two nights in an igloo I built in
our local mountains at 9500 ft (2896 m) elevation, where the low
temperature inside the igloo was 28 F (-2 C) and outside temperatures
were near 0 F (-18 C). The second was a nine day trip in Yellowstone National Park,
Wyoming, where we established three different igloo base camps and slept in
igloos eight nights. Low temperatures inside the igloos ranged from 18 F
to 25 F (-8 to -4 C), while outside temperatures ranged from -16 F to 4
F (-27 to -16 C).
I also did three overnight winter camping trips in our local southwest Colorado
Mountains. The first was in a double wall tent where the overnight low
temperature got down to 16 F (-9 C), the second trip was in a single
wall tent where the overnight low was 17 F (-8 C), and on the third trip
I slept in the open (no tent) where the overnight low was 20 F (-7 C)
|With two people in a double wall tent, I stayed warm while
sleeping in a 20 F (-4 C) rated sleeping bag and the Penguin
Bivy on a 16 F (-9 C) night.
On the igloo trips I slept in a 15 F (-9 C) rated synthetic sleeping bag
with a full-length zipper on the left side, and on the remaining trips I
slept in a 20 F (-7 C) rated down sleeping bag (GoLite Adrenaline 20,
which I am also testing) with a half-length top zipper. On all trips I
slept on a thin inflatable sleeping pad on top of a closed-cell foam
sleeping pad. The pads were under the bivy, not inside it.
in the Integral Designs Penguin Reflexion Bivy inside a
double wall tent.
Fit and Roominess—The
Penguin Bivy has plenty of room inside for the 15 F (-9 C) synthetic and
20 F (-7 C) down sleeping bags I used in my testing. It has lots of
girth at the head end and much less girth at the foot end, with roughly
the same proportions as my sleeping bags. I inserted a 0 F (-18 C) down
sleeping bag inside the bivy to see how it fits, and found it comes
close to filling up the bivy, especially at the foot end. I suspect that
a sub-zero sleeping bag would be a tighter fit.
With the sleeping bags I used, I found the Penguin Bivy to be plenty
roomy inside. There was ample room to store items between my sleeping
bag and the bivy to keep them warm, and to reach out of my bag to place
them in the right location. My process for getting settled at night was
to zip the bivy from inside to get my breathing hole in the right
location, zip up my sleeping bag to line up with the breathing hole, and
adjust the bivy opening if necessary.
Warmth and Comfort—While
there is no easy way for a tester to actually measure the gain in warmth
from using a bivy, my estimate is about a 5 to 10 degree F gain (3-6
degree C) from the Penguin Bivy. Its
SympaTex Reflexion fabric does seem to make some difference in warmth.
On nights where the air temperature was challenging the temperature
rating of my sleeping bag, I was toasty warm inside the Penguin Bivy,
although I was wearing lots of clothes inside my sleeping bag just to
Features—The Penguin Bivy
has three sliders on its half-length top zipper that allow positioning a
breathing hole in the right place, plus an extra opening for ventilation
if desired. That feature worked very well for me.
Another feature of the bivy is its stiffened shape in the head area to
keep the fabric above my face. I could not put that feature to use
because I did not want to zip myself entirely inside the bivy, and rely
on an air supply only through the vent at the top of the bivy. That
would put a lot of moisture from my breathing inside the bivy and would
be very claustrophobic. Instead, I kept an opening in the zipper that I
could breathe through, as shown in the photo above. On really cold
nights my face got a bit cold using that technique, so I had to close
down the size of the opening. When using a breathing hole, the stiffened
fabric was more of a hindrance than a help, because it made it harder to
place the breathing hole right at my mouth so I exhaled outside the bivy.
I also found that the Penguin Bivy’s top half-length zipper works best
with a sleeping bag with the same zipper location. I used the bivy with
a sleeping bag with a left side zipper and found it to be significantly
less convenient compared to a top zippered bag, such as the GoLite
Adrenaline 20 that I am also testing.
waterproof-breathable SympaTex Reflexion fabric used in the Penguin Bivy
functions similar to a polyurethane laminate (not very breathable), so I
was concerned about condensation inside the bivy.
On nights that I slept in igloos I had only minor condensation
inside the bivy. However on two of my other trips, in colder
temperatures, I had abundant condensation (frost) on the inside of the
bivy. This occurred on a still 16 F (-9 C) night while sleeping in a
two-person double wall tent on top of a 10 ft
(3.1 m) deep snowpack, and on a breezy 20 F (-7 C) night while
sleeping under the stars, also on snow.
(frost) inside the Penguin Bivy after sleeping under the stars
on a 20 F (-7 C) night.
fear I had on my extended igloo trip was moisture accumulation in my
sleeping bag. However, I didn’t have any problem at all. I hung my
synthetic sleeping bag on a clothes line every day or two just to make
sure it stayed dry. Inside the igloo, I kept the bivy around my sleeping
bag all the time to prevent any moisture from getting into my sleeping
bag from the outside.
Durability and Packability—The
entire bivy is constructed of the SympaTex Reflexion fabric, which has a
durable nylon face. After two months of use there are no signs of wear.
However, at 22.3 ounces (632 g), the Penguin Bivy is no lightweight. I
would personally be reluctant to carry it in a backpack and use it in
combination with another shelter. Rather, I would be more inclined to
use it by itself as my primary shelter, perhaps with a small tarp over
the head area in the event of rain.
Report (July 16, 2008)
and Type of Use
After my Field Report on May 10, I had little time left to test the
Penguin Bivy under really cold conditions. I did one more snow camping
trip in mid May where I backpacked to 11,700 ft (4566 m) and slept
overnight without a shelter, on top of an 8 ft (2.4 m) snowpack. The
nighttime temperature only got down to freezing (32 F/0 C), but a strong
convectional breeze kept up all night. I slept in a 20 F (-7 C) rated
sleeping bag (GoLite Adrenaline 20) with a center half zipper.
|Morning after a night spent sleeping under the
stars in the Integral Designs Penguin Reflexion Bivy.
I have very little to add to my comments in my Field Report. On the one
additional trip described above, I did not find any condensation inside
the bivy the next morning. I estimate that the bivy added about 10
degrees F (5.6 degrees C) to the overall warmth of my sleeping system,
in part by greatly reducing convective heat loss when I slept in the
The unique feature of the Integral Designs Penguin Reflexion Bivy is its
use of SympaTex Reflexion fabric, which contains a thin aluminum layer
to reflect back and conserve body heat. My impression based on my
testing is that the bivy adds about 10 degrees F (5.6 degrees C) of
warmth to a sleeping system, depending on the conditions. Although I
have no means to measure the fabric’s breathability, I note that I had
few problems with condensation inside the bivy. The only instances of
condensation I encountered were after very cold nights, where I found
quite a bit of frost on the inside surface of the bivy. The bivy is well
designed and constructed, and is sized to fit over a sub-zero rated
sleeping bag. At 22.3 ounces (632 g), the Penguin Bivy is an average
weight for a bivy made of heavier, more durable fabric.
I would like to thank Integral Designs and the BackpackGearTest Group
for selecting me to participate in this test.