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Oware EPIC / Silnylon Bivy Sack

Oware EPIC / Silnylon Bivy Sack


by the Product Review Staff | 2002-07-04 03:00:00-06

Manufacturer’s Website:


Regular Size

  • Materials: Top Fabric - 1.8 oz./sq. yard EPIC by Nextec
  • Materials: Bottom Fabric - 1.3 oz./sq. yard Silicone Impregnated Nylon
  • Total Bag Weight no Bug Netting: 10.5 oz. (9.9 oz - measured)
  • Total Bag Weight with Bug Netting: 12.0 oz. (12.3 oz - measured)
  • Length: Up to 6' user height
  • Width: 35"
  • Optional Bug Netting Available
  • MSRP: $110

General Description

Oware's EPIC-and-silnylon bivy sack may be the only bivy sack on the market to use a waterproof silicone impregnated nylon (silnylon) fabric for the floor and a highly water resistant, very breathable silicone encapsulated EPIC fabric for the top cover. It is also a very light bivy weighing in at less than 10 oz for the model without bug netting. As such, it is one of the lightest bivy sacks on the market. For both price and performance this bivy is targeted at the serious ultralight backpacker and/or climber.

Oware's EPIC/silnylon bivy is a basic but functional design. Its only "value added" functional feature is a zippered hood. The bivy comes in two hood closure options: one with a lighter No. 5 dual slider zipper (the user supplies a separate mosquito head net); and one that comes with a heavier single slider #9 zipper and zip-in mosquito netting. There is a tie-out at the hood for the model with bug netting to keep it off your face. One could easily read a book or comfortably sleep in this configuration even under heavy mosquito pressure (see picture).


The Oware bivies have a bathtub floor of silnylon and a top cover of ripstop 1.9 oz/sq yd EPIC by Nextec. The EPIC top is offered in a nice, earthy "Stealth Green" while the floor can be specified as either green or gray. There are tie-out loops on the four corners so the bivy can be staked to the ground for windy conditions. The bottom of the bivy has a separate foot-box panel to prevent loft compression at the foot end of a sleeping bag. Construction quality is good with taped seams and sound stitching. Seam sealing is left to the user, although with the EPIC one may not want to bother. While a great idea, the zip-in mosquito netting could be improved by using a much lighter zipper.


Our reviewers are generally keen on EPIC fabric for some applications. EPIC is more water- resistant than DWR-treated microfiber fabrics. It depends on silicone encapsulation of individual fibers to repel water and to close spaces between fibers. Contrary to popular belief, EPIC is somewhat less breathable than standard microfiber fabrics, but it still remains more breathable than PTFE and PU laminates and coatings, including Gore-Tex, ConduitSL, and Pertex Endurance. According to the manufacturer, EPIC is water- and wind-resistant to 4 psi, thus significantly more so than uncoated microfiber fabrics, which rely solely on an external DWR finish for water resistance. The water resistance is a permanent feature of the EPIC fabric and cannot be washed out like a durable water-resistant finish (DWR). EPIC is good for intermittent light drizzle and for use in shelters with heavy condensation, but it may not be appropriate for protecting the user from sustained rain or wet, heavy snow. Think of EPIC as a little less water resistant but more breathable than a standard waterproof breathable fabric, and a little more water resistant but less breathable than a standard uncoated microfiber fabric.

The Oware bivy is cut just right. There is plenty of room for some extra gear and for layering a large, warm down jacket over your sleeping bag. However, the cut is not so roomy that the bivy billows around in the wind or adds unnecessary weight from surplus fabric. The bivy hood is large enough for a generous pillow and plenty of gear (e.g. flashlight, pocket knife, hat, water bottle etc.), making it nice not to have to grope around for these essentials in the dirt when you need something at night.

Our staff has 12 field nights in the Oware bivy in temperatures from 5 to 50 deg F. In the cold and humid conditions of winter and early spring in the Northeast, the bivy added some warmth and plenty of protection from blowing wind. With the breathable EPIC fabric we had no problems with condensation. The hood zipper works well for adjusting bivy ventilation to improve breathing comfort and condensation resistance, and the dual sliders allow you to locate a ventilation hole exactly where you want it. It was also a pleasure to zip the hood completely shut (which is not recommended with waterproof-breathable bivy sacks due to the buildup of carbon dioxide in the shelter) in the wee hours of the morning and get warm and comfortable for an extra hour of sleep.

In the Southwest, we found the bivy useful to stake to the ground and prevent sleeping bags from blowing off across the mesa. The bivy also kept volumes of blowing, dust, sand, and other debris out of our reviewers' sleeping bags. Exposed all night to desert winds, the bivy gave excellent protection from penetrating winds. They used the bivy and a silnylon poncho as our only shelter. (No surprise, we never took the poncho out of our packs).

Our Northern Rockies review team used the bivy primarily in spring conditions in river valley bottoms where the dew point and humidity were high enough, and the temperatures cold enough (due to temperature inversions), to promote dewfall at night. The Oware bivy easily shed falling dew, which soaked everything in sight by morning. However, the presence of moisture on the bivy sack surface seemed to inhibit breathability, as some condensation was observed under these conditions. More testing will need to be performed to validate this hypothesis.

The only restriction for the Oware bivy is that it is not intended for use as your sole shelter, if you think you may be camping in steady rain or wet snow. EPIC is not fully waterproof, and while it sheds a lot of precipitation and reduces condensation, it will not keep you dry in a night of significant amounts of precipitation. You will risk having a very wet down sleeping bag in the morning (but the bivy is worth exploring as a cover for a synthetic-fill bag).

Overall Impression

Oware's EPIC/silnylon bivy may be the best all-around ultralight bivy sack on the market. It is perfect for additional protection in windy and colder temperatures. It is waterproof enough to protect your sleeping bag from a condensing single-wall tent, or a minimal tarp that may have some rain spray underneath, or even a snow cave. Yet the EPIC cover suffers from less condensation than fully waterproof breathable bivies. Best of all, at only 10 oz, it weighs less than many hikers' ground sheets and just about every other bivy sack on the market.


"Oware EPIC / Silnylon Bivy Sack," by the Product Review Staff. (ISSN 1537-0364)., 2002-07-04 03:00:00-06.