Emergency Shelter

S

swami_p

Joined
Jun 1, 2004
Messages
76
Currentley I carry a reflective space bag for emergencies in my pack, but I have been considering switching to a very light and compact backpacking tarp to take the bags place. I haev also thought of the land-shark bag at www.land-shark.net. what do you think? The tarp is definatley more versitile but is does not refect the heat is it worth to lose this function?
 
Swami P:

Here's what I believe about space blankets. In all but a very few, unusual conditions, the reflective property of space blankets is nothing more than marketing hype. The exceptions may be when using the blanket as a fire reflector, or when you're hiking naked in outer space (or in a local complete vacuum).

The primary use of these things as emergency devices is simply to stop convective heat loss in air. That is, they provide a wind barrier. As small, light sheets of windproofing they're great.

A silnylon tarp of almost any dimensions from 7 x 9 ft to 10 x 10 ft will provide a lot more flexible shelter options. The advantage of silnylon over plastics or platic-coated nylon is its light weight and compressible volume.

Such a tarp would be bigger and heavier than a space blanket, but much more versatile and durable than a space blanket when used as an external shelter. You have to factor in cordage for rigging.

I have no experience of the land shark bag or the Thermo-Lite Emergency Bivy bag, but these strike me as useful things because they're preformed bags that are wind and water barriers. Not all emergency situations call for a tarp-like shelter, and wrapping the tarp securely around you might not be as easy as slipping into a ready bag.

Bear
 
Has anyone ever heard of the heat reflective properties of the space blankets etc. being tested? It seems like it would be relatively easy to check using an IR scanner. As bear stated they make a good wind blocker.
Gene
 
Space blankets are very noisy to sleep in and they are a one use item. If you sleep with them under you or rubbing against anything they get degraded very quickly. The reflectivity is a plus in my opinion but it is over rated. They are waterproof, windproof, and very compact. They can also be used as a huge signal mirror.

As was stated they will greatly increase a fire reflectors efficiency.

I want to test one inside a debris shelter strung up with a line of paracord under the ridge pole and tied off on each corner. I think it would reflect any heat back towards you and lessen any drafts or drips that make it through
the debris. It would also make a impenetrable barrier for body heat to rise up and be trapped against. Hung up in this way it would also last longer. I haven't tried this yet though so it's only a theory. Mac
 
I find the reflective blankets do work well to hold down temperatures in hot desert areas when used as a tarp and rigged doubled over with dead air space between, especially over a depression or trench. I notice about the same effect when using a flourescent orange tarp as well. I'm not convinced of the usefulness of the silver blanket as a signal device - usually the blanket is too crinkled to effectively focus the sun's rays - a mirror is much better. I know of at least one instance where a desert hiker signaled repeatedly at a low-flying helicopter with such a blanket, but had no luck in attracting the pilot's attention.
 
MarkJ,

I know of a group lost in a jungle area that climbed to an exposed hilltop and used one stretched between two people to attract a search plane. I agree that a signal mirror is far superior and I always carry one when hiking in Brazil. I still think it's worth a try as long as the blanket isn't crumpled from sleeping in it. Mac
 
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