Actual effectiveness of space blankets

bushman14 said:
somewhere I have seen a pic of a guy sitting with the blanket wrapped around his neck like a teepee. He had a candle inside and supposedly it kept him warm. Maybe someday I'll try it when I am really, really bored.
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that is a basic survival technique I teach people who have never been in the woods. It costs 3 bucks for the balnket and candle and lighter, and they can try it out and see what happens. If every person that venturd into the woods or ski hills had just those three things and knew how to use them, more lives would be saved.
 
I was a homeless backpacker for several years so i got a lot of experience sleeping in the outdoors and being naked even in a sleeping bag is quite a bit warmer than having clothes on. I would inhale air from outside the bag and exhale it into the bag blowing it up with hot air like a balloon. it worked really well even in below freezing especially if you can improvise some way of getting off the ground because the dirt really sucks the heat out of you.

At first i was a little worried about sleeping nearly naked in public places like parks but after a while I realized that NO ONE bothers 6 foot 200 pound naked homeless guys with skateboards for pillows.

I was thinking that a space blanket and a wool Hudson bay style blanket used together should work really well.
I love wool and with the reflection heat of the space blanket it would be a nice light bedroll. Also the wool would keep the space blanket from being ripped.

Another fabulous cheap survival tool is those little survival candles. I always have a few in the truck in winter because here in the North people who leave their cars in a storm die. A couple of those candles will heat a whole car for the entire night without having to run the engine. They give off an amazing amount of heat and a big bag is a couple bucks at the dollar stores.
 
DOC-CANADA said:
Hey TL,

As another perspective, Ron Hood talks about the little space blankets in his survival kit video. He says that ideally, they should be worn under one layer of clothing, mostly to protect the space blanket.

He says he has also used them on skiing accident victims, to keep them warm until help arrives.

Doc
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Aside from protecting the material that's also the only way to really capitalize on the the reflected radiant heat thing. Same as with the wrapping up babies idea. I have no data but conversely I don't conceive of a great many returns when the fabric is a foot away from the body used as a tarp.
 
BOOMSTICK said:
baldtaco-II
that vango shelter is 40 pounds. that is $80.00 USD
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Perhaps, I wasn't shopping around for one. There's a four man one herefor £40, so that's £10 each.

Still, I wouldn't be using that. Start heading down that route and to my mind you're already on a planned over night, in which case I'd be using something else. I really only mentioned those to keep my powder dry. You never know when someone is going to turn up with something very tenuous in an attempt to support their case – something that could just about be construed as a space blanket because it has a reflective surface. In anticipation of that I headed it off at the pass by ramping up on something that could equally precariously be described as a plastic bag.

Keeping it simple, and using an example of a space blanket as the item that I think most conceive of when they consider them – that thing that gets handed to sportsmen post event, and I'll happily stack that against that plain big orange plastic sack in the first picture. Those in particular are £3.75. And there's a 8'*4' bag here for £4.99. Smaller ones are cheaper. Anyway, I don't believe we should be judging performance or usefulness on price.
 
I remember a kid in Boy Scouts trying to sleep out overnight in one in summer, I think he ended up in a sleeping bag before the night was over. Course that was decades ago
 
They are very effective, yet very vulnarable.
They can make a huge difference when it comes to an unplanned bivouac.
When I had a few of those I invested in a blanket that's laminated on some ripstop fabric. This is far more durable and can be used more then 1 or 2 times. This blanket is part of my basic kit always.

You can really feel the effictiveness against the bare skin. It's like sitting in front of a toaster. Wrap a blanket or a bag around, and you'll be comfortable. On a windy sub zero Alpine ridge tho, I'm not likely to strip. But take it with you in the bivy bag, and you will be more comfortable then without for sure.

Some of the blankets have tiny holes in them that will assist in breathing away moistured air.. Be sure the bag breaths also..
 
Yes, apparently the Defence Clothing & Textiles Agency here at Farnborough concluded that they were fragile, and that once punctured or torn they come apart very easily.

....

If it were my money I'd be dumping the whole blanket notion and going with a Reflexcell bag. You can scrimp and get it in blanket formation, in fact loads of them have already made their way to Iraq and Afghanistan.

“US Army medics are now trained to wrap casualties in Blizzard Survival Blankets as their first response to preventing hypothermia in trauma cases - even in hot weather.
The Blizzard Survival Blanket is recommended as the first choice for keeping casualties warm by the 2007 Prehospital Trauma Life Support Military Version Sixth Edition (PHTLS Military Version 6E), produced by the globally respected National Association of Emergency Medical Technicians (NAEMT).
PHTLS says medics' initial response to trauma cases should be: “After any immediate life-threatening issues are addressed, wet clothes should be replaced with dry clothes, if possible, and the casualty should be wrapped in a Blizzard Survival Blanket.”
Hypothermia in trauma cases occurs regardless of ambient temperature, PHTLS says, and prevention is far easier than correcting it: so stopping heat loss should begin as soon as possible after wounding.
The guide places the Blizzard Survival Blanket first in a ‘hierarchical equipment list for prevention and treatment of hypothermia'.”
It's also seizing a market share amongst forces operating here.

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It should be pretty obvious why a bag is better than a blanket. Here we have something that incorporates everything good about a space blanket into a bag system that is more useful
 
DOC-CANADA said:
Hey TL,

As another perspective, Ron Hood talks about the little space blankets in his survival kit video. He says that ideally, they should be worn under one layer of clothing, mostly to protect the space blanket.

He says he has also used them on skiing accident victims, to keep them warm until help arrives.

Doc
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Sorta' reminds me of the problem with those cheesy "emergency ponchos." Every bush in the woods is reaching out to tear them up.
 
hollowdweller said:
I was backpacking and camping right on the edge of a canyon and the wind was whipping and I was getting pretty cold. I had a 20 degree bag and I don't think it was 20 degrees outside but I guess it was the wind. I kept waking up cause I was cold. Finally I pulled a cheap Sportsmans Guide Space Blanket out and put it over my sleeping bag and I could tell the difference and slept the rest of the night fine.

Not sure they would save you if you were under dressed and it was minus 5 but they would help.
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A couple friends and I were in a similar situation, but a little colder and we were at 4200' in the Catskills in January. We were pretty cold and put our emergency blankets inside our sleeping bags. Aside from a little condensation, it actually worked pretty well. I was definitely warmer with it and slept better.
 
Bushman5 said:
true, BUT i can deal with a few tears in the blanket if it keeps me warm until daylight.....;)
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Thas' why the duct tape is inyur kit.
(Since the main values are keeping out the wet, wind-blocking and trapping a bubble of heat, holes are an issue.)
 
If I were using it with a bag, I'd probably opt for putting it inside the bag, sort of like the vapor liners used by some of the extreme cold weather climbers. If it were wrapped too snugly around the outside of the bag, I'd be concerned about condensation building up and compromising the bag's insulation.

DancesWithKnives
 
It has to be cold enough outside to make the use of a space blanket inside a sleeping bag comfortable. Otherwise you end up soaked in sweat, instead of mildly damp, and you don't want to comprimise either your clothing or sleeping bag's insulation. A better bet might be to lay the space blanket on the ground, place your sleeping bag on to it then form a half leantoo over the top of the bag, with just enough room between the top of the leantoo angle to get in your bag. This will reduce windchill, and still aloww the sleeping bag to vent mositure IME.
 
Good points. I tried a vapor liner only once and it was quite a bit below zero Fahrenheit. Felt clammy but not terrible. I now have a two-bag system that's good to at least -40 without a vapor liner.

What do you think the minimum temp would have to be before you'd want to put a space blanket inside a bag that wasn't warm enough?

DancesWithKnives
 
I'm apt to say 0'F after 35 years of camping and reinventing the wheel at least once a trip. It would be better to buy a Space brand bag as opposed to a blanket for this use IME. This way you are enclosed from your sleeping bag, and the humidty levels at your skin stay relatively stable. Once you get out to pee in the night though you will have to be cold intially until the vapor level re-stabilizes inside the bag. Wearing a thin layer of fleece pjs is best when dealing with a vapor liner bag inside your sleeping bag IME. If you have enough camping experience to be safe then try using vapor barrier gear, otherwise it could turn into a hypothermic danger if the weather is not cold enough. wiggys sells actual vapor barrier clothing, which is worn at your skin, with or without anything else on top inside your bag. When using 2 sleeping bags, which is a different thread, always use the down filled bag under a syn filled bag. Reason is that this way all of the moisture from your night sweats will migrate through to the outer bag. Syn bags are much easier to dry in the Winter than a down bag IME.
 
That sounds like a pretty reasonable analysis.

When I was considering the question, I thought that perhaps it would also depend on the insulating value of the bag relative to the outside air temp. For example, if you were attempting to sleep in dry, windy 15F degree weather in a 40F rated Marmot Hydrogen bag, the difference between the insulating quality of the bag and the actual temp might make it possible to use a vapor liner without excessive condensation. I've never tried it so it's just conjecture on my part.

I agree that a space bag would be far superior to a space blanket when used inside a sleeping bag. I was using a fully enclosed vapor liner with some fleece long underwear when I tried the approach.

As for getting up at night when moist from a vapor liner, you know those wide-mouth Lexan Nalgene bottles that have caused concerns over chemicals leaching into your water? Well they still make a fine in-tent urinary management system!

Thanks for your thoughts,

DancesWithKnives
 
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