Reviews > Shelters > Tarps and Bivys > Integral Designs South Col Bivy > Jim Sabiston > Field Report

Field Report - Integral Designs eVENT South Col Bivy

Date: January 12th, 2004

Reviewer Information

Name: Jim Sabiston
Age: 49
Gender: Male
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 light-weight 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 X12 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 permit’s a greater variety of set up options, one of which provides nearly the same level of protection as a tent.

The total combined weight of this system is:
- 12 oz (340 g) Ground cloth
- 23.25 oz (6.59 g) Integral Designs eVENT South Col Bivy (with stuff sack)
- 28 oz (794 g) Tarp (all up, with extra lines and ground stakes)
3 lbs 15oz (1.79 kg) Total

As compared to a full winter tent set up:
- 12 oz (340 g) Ground cloth
- 7 lb 8 oz (7.4 kg) Eureka Alpenlite 2XT Mountaineering tent with guys and stakes
- 6 oz (170 g) reflective tent liner (a Thermolite emergency blanket)
8 lbs 10 oz (3.91 kg) Total

(Note: Using a smaller, lighter ground cloth and a smaller, lighter tarp, it would be possible to save considerable additional weight, possibly as much as a pound (.45 kg).

This gives a total weight savings of 4 lbs 11 oz (2.12 kg)! In addition, the system offers a huge savings in pack volume, as the bivy/tarp combination requires less than a quarter of the pack space as the tent. The tarp can also be stored on the outside of my backpack, permitting even greater interior space savings. This allows either the use of a smaller, lighter pack and/or more space for food and other gear. Another advantage is the quick set-up and breakdown times. I can set up or pack my campsite in about half the time, as compared to my mountaineering tent, with this system.

Naturally, there are compromises that come with a system like this, but some additional benefits as well. These will become apparent as I get into the details of my field experience.

Field Experience:

We have experienced a very mild fall season in the Northeast. With the exception of a northeaster that dropped 18 inches of snow in one day (which was all gone three days later!), the temperatures have generally remained well above freezing. This has allowed me to focus on the bivy’s ‘warm’ weather performance. As I had never used a bivy before and it is my intention to use the Integral Designs eVENT South Col Bivy as part of a three season shelter system, this milder weather has worked out well for me, as it has also allowed me to build up some experience with the bivy prior to delving into the more harsh and difficult deep winter weather.

One of my first concerns was how the bivy would perform in mild, humid weather. Much to my surprise, the eVENT South Col Bivy has handled these difficult conditions remarkably well. I expected overheating and condensation to potentially be an issue, but neither has been a problem. This is even more surprising in that I have been forced to use my winter sleeping bag in temperatures where I normally would not even consider it . This is due to the simple fact that my winter bag has the zipper on the left side, matching the bivy. I tried my right hand zippered Spring/Fall sleeping bag, but it proved far too awkward to have the zippers on opposite sides. I am a warm sleeper, and my winter bag (a The North Face Superlight down bag rated to 0 F (-18 C)) normally would not be considered until the temperatures dropped below 30 F (-1 C). My first time out, I expected a long, hot, sweaty night and, in fact, this is what I started to experience. Conditions were warm, 50 F (10 C), very humid and calm. However, opening the zipper of the sleeping bag and then the side zipper of the bivy provided enough ventilation that I slept quite comfortably, even under a tarp! There was absolutely no indication of condensation inside the bivy.

My coldest night to date was spent on Fire Island, in the Otis Pike Wilderness Preserve. Conditions were windy and humid, with temperatures dropping to about 30 F (-1 C). The only problem I have experienced with the bivy occurred this night. I had closed the face zipper, leaving an opening of about 10 in (25 cm) in the middle of the zipper. The bivy is roomy enough to roll around in, even for a big guy like me, and I take full advantage of this, changing my position often during the night. Unfortunately, the zipper does not move with me! The result is that I ended up breathing into the bivy, rather than exhaling directly outside through the zipper opening. Predictably, I ended up with a significant amount of condensation on the inside of the bivy near my face and on my sleeping bag. Once the problem was discovered, I made the necessary adjustments and the condensation was gone by morning. Having to wake up enough to remember to adjust the zipper opening every time I roll over is a real nuisance. What I found works better, at least in the mild conditions experienced so far, is to leave the zipper fully open. The ‘brim’ of the bivy hood has provided plenty of protection, when used under a tarp or lean-to, and the likelihood of insufficient venting is greatly reduced.



Fig. 1: The Integral Designs eVENT south Col Bivy with tarp and emergency blanket ground cloth.

As mentioned in my initial report, I was not entirely satisfied with the clearance provided by the wire hoop. This continues to be the case, but it is still better than if there were no hoop at all. My experience, as previously noted, indicates that the zipper is generally better left open as wide as possible, weather permitting. This makes my sleeping position much less critical, as regards exhaled breath being directed right out of the bivy, which is very important. I was tempted to not close the face zipper at all on several occasions, but the wire hoop is not supported properly by the bivy structure unless the leading zipper is closed. To clarify, closing the face zipper completely, moving the first zipper head to the full left position, then moving the second zipper head to the full left position as well, gives the wire hoop proper support and keeps the face opening as large as possible. Once this is done the hoop stays up well enough even if the secondary face zipper is fully opened so venting is not compromised, but it is necessary to take the extra step. This is the setup I find myself using most often.

When packing the bivy, I found that it is worth taking an extra moment to carefully roll the wire into a fairly tight loop prior to stuffing the bivy into the provided stuff sack. I have gotten into the habit of first rolling the wire hoop this way and then placing the wire portion of the bivy carefully into the stuff sack bottom and then stuffing the rest of the bivy into the sack on top of it. I have found that the wire stays much straighter this way and it should last much longer before metal fatigue requires its replacement. When I just stuffed the bag into the sack without this extra step, the wire invariably came out a twisted mess and required much fiddling and straightening before it would take on a proper smooth curve.

As I anticipated, converting from a tent to a bivy has required certain logistical compromises. My habit of reading every night has taken on a whole new challenge. I found I can read inside the bivy while lying flat on my back and placing the book (a typical paperback) on my chest, but is a tight fit and, ultimately, not very comfortable. It seems to work out much better if I lie on my side, with the book on the bivy or sleeping bag bottom. But my arm goes to sleep after a while. (Life can be very difficult!) A headlamp has proven to be very effective for lighting the interior, but is frequently blocked by either a fold in the sleeping bag or the bivy. This is not much of an issue once I settle down into one position or another.

There is plenty of room to move around inside the Integral Designs eVENT South Col Bivy. Obviously, there can’t be the same room as a tent, but the bivy has proven to be quite comfortable. As long as the face zipper is open, I did not feel claustrophobic at all. In fact, I found the experience to be rather snug and pleasant. One of the things I really like is that I stay on my sleeping pad all night, as I place it inside the bivy with my sleeping bag on top of the pad. The combination is very stable and there has been no tendency for everything to wander. There is sufficient room to store various bits of gear inside, but larger bulky items must remain outside. I do not carry much in the way of extra gear, so this typically means only my cooking gear and pack. Most loose items just get tossed into the backpack, which I then keep on the ground cloth, under the tarp and alongside the bivy.

Using a pee bottle has not proven to be unduly difficult, but it has become apparent that a bit of extra care is needed, due to the close quarters. A minor mishap occurred at about 3:00 am one night when I waited a bit too long and, in my haste, did not properly clear the sleeping bag, which of course, slid into my ‘line of sight’ and into the ‘working area’ at a critical moment and resulted in a small accident! If I had a concern about using a pee bottle in the bivy, it was simply that if I experienced some, umm, spillage, it would be in very close quarters. This fear proved to be well founded! I will be more careful in the future.

General Observations:

The Integral Designs eVENT South Col Bivy is very lightweight and packs very small. The bivy has proven to make an excellent primary shelter in combination with a tarp. In areas such as the Catskills and Adirondacks, where lean-tos are easy to come by, the bivy is a natural! It provides that extra bit of protection when sleeping in an open shelter that makes an otherwise borderline night really pleasant. Carrying a tarp provides all the backup shelter I need on those rare occasions when I find the lean-to already occupied. The limited temperature range I have experienced so far does not allow me to comment on whether or not the bivy extends the temperature range of my sleeping bag.

I have not had the chance to really test the waterproof characteristics as far as a serious soaking goes. The tarp or lean-to is intended to take the brunt of any precipitation. With my set-up, the bivy is actually the second line of defense and in this application, and it has performed its weather protection duties flawlessly, giving excellent protection on several windy, wet nights. Integral Designs claims of the extreme breathability of the eVENT fabric appear to be accurate as condensation has not been detectable, even on warm humid nights, provided exhaled breath is directed outside the bivy. There is plenty of room for my sleeping bag to expand properly and the light weight eVENT fabric shows little tendency to compress the sleeping bag’s loft.

The reduction in weight and pack space are enormous, as compared to my usual cool weather shelter. This is no small consideration. The backpacking style compromises I’ve made to achieve this have been worthwhile. Except for the roominess issue, which would be the case with any bivy, I have been very pleased with the performance of the Integral Designs eVENT South Col Bivy.

Continued Testing:

Now that winter has finally arrived, I will have the opportunity to move into the next, and more critical, phase of my testing. Plans are already in the works for two extended winter trips in the Catskills and Adirondacks. In freezing weather breathability will be all the more important. Will there be any condensation build up at all? If so, will the close quarters of the bivy prevent it from freezing? This will be a very important consideration for multi-day cold weather trips.

Remaining concerns are how I will adapt my equipment habits to not having a tent in freezing weather. The bivy will continue to be used in lean-tos, under a tarp (even in the snow), and I want to try it in the open. How does that waterproof zipper hold up when pressed into snow while I am sleeping in the bivy? Other factors, such as durability (especially of the lightweight, waterproof bottom) will be observed. Of course, I will keep an eye out for indications of wear and tear on the very light eVENT fabric. So far, except for a bit of dirt smudging, the bivy looks almost new.

I also look forward to the opportunity to practice and refine my Winter Mountaineering training with this bivy. One of my goals is to determine just how light I can go with my winter gear without compromising comfort and safety. The Integral Designs eVENT South Col Bivy should provide an excellent vehicle for refining my winter survival techniques along these lines.

Lastly, I have begun experimenting with the concept of using a Crazy Creek fold-up chair inside the bivy! I carry this chair as part of my standard winter gear (it doubles as a closed cell foam sleeping pad) anyway, so this could be a nice addition to its work itinerary! Initial experiments have been promising.

I would like to extend my thanks to Integral Designs for the opportunity to test this very interesting product.

Reviews > Shelters > Tarps and Bivys > Integral Designs South Col Bivy > Jim Sabiston > Field Report