Adventure Medical Kits (AMK) Emergency Sleeping Bag is the classic Mylar space blanket taped along the sides to form a bag. The packaging promotes it as an emergency sleeping bag to ‘survive the unexpected night out’.
The AMK Emergency Sleeping Bag is made of polyester plastic film coated with a thin, sprayed aluminum coating. The bag is shiny, crinkly and when held up to the light you can see through it – barely. It is taped along two sides and reinforced around the opening with yellow polyester tape.
The bag provides a vapor barrier, preventing heat loss by evaporation and convection. The shiny surface will reduce radiant heat loss by up to 90% according to the packaging. The bag will not prevent heat loss by conduction in any significant way.
The advantages of a bag over a space blanket are increased wind resistance and the ability to remain in place with tossing and turning. It will also provide a much more effective vapor barrier. Its disadvantages include difficulty getting an injured person into the bag and the potential for condensation inside the bag. However, on a cold windy night, it would be much easier to convert this bag into a space blanket than taping up a space blanket to form a bag.
The bag can be torn on sharp sticks or rocks and rips can propagate rapidly once started. The tape along the entrance of the bag probably reduces this possibility. The bag is labeled as an emergency sleeping bag. The rustling noise and fragility of the bag would stop most people from using it for anything more than emergencies.
The bag is generously sized for one person but is a real squeeze for two. When hypothermia threatens it is often desirable to get two people into a bag. While two people can get in this bag, it appears there would be a serious danger of ripping it.
There are many uses for a large waterproof sheet like this in an emergency including: collecting rainwater, keeping rain off a sleeping bag and using it as a sunshade.
An alternative would be to carry a polyethylene plastic trash bag for dual service as a pack liner and emergency sleeping bag. A similarly sized polyethylene bag is approximately twice the weight of the Emergency Sleeping Bag.
The AMK Emergency Sleeping Bag is an improvement over the traditional space blanket if you think you may get caught out without a sleeping bag. This bag and a warm jacket may be enough to get you through an unplanned night out. The Emergency Sleeping Bag is cheap and light and it may be worth considering for your daypack or survival kit for times when you don’t carry a sleeping bag.