What Exactly is a Bivi Bag

Traditionally bivi bags were simple and lightweight fabric coverings to be pulled over a sleeping bag to ensure they were waterproof, however, there are various types and qualities which are used effectively today by professional climbers and mountaineers, soldiers and the elite special forces through to the weekend hikers and minimalist backpackers.

Typically they are are small and lightweight making an easy addition to to a Bergen or backpack, as opposed to the extra weight and space required when carrying a tent. However, many of the less serious campers and hikers will gladly accept the extra weight of a tent as an exchange for the increased level of comfort it may provide. But for the more serious mountaineer a bivi is an absolutely essential part of their kit which can be life saving and used to provide a simple but highly effective emergency shelter in dangerous situations. Especially for those in the armed forces a bivi is a lightweight minimalist piece of kit which can be used to a soldiers advantage and potentially be life saving.

In their earlier forms bivi’s did though have a some flaws not least in the fabric which was used which did not breathe well and would often leave its occupant wet as moisture was unable to escape.

More recently advances in technology have eased this problem significantly, with the introduction of Gore-Tex fabric making for a breathable yet highly waterproof material which allows for moisture from the body to escape yet keeping the the elements out.

Another problem faced was the fact that the bivi could not be fully zipped up due to carbon dioxide build up caused again by fabric which was not breathable, this in turn allowed for an escape of heat and and loss of fully effective insulation.

With the introduction of Gore-Tex Exchange Lite fabric this problem has again been counteracted and an exchange of carbon dioxide and oxygen is now possible allowing for the bivi to be fully zipped up and provide optimised insulation.

Bivi Bags in Modern Times

Most recently bivi bags have been adapted to form a bivi shelter which has become increasingly popular with many including those keen on fishing.  Cross between a small tent and a bivi bag this still manages to remain lightweight and compact, however allows for extra room and head space with the introduction of hoops or poles around the head and feet. This can provide advantageous conditions for storing kit and ensures increased flexibility allowing the adventurer to read or write with ease inside their shelter. Also with the shelter held taut this acts as further protection form any moisture which may accrue from seeping into the bedding.