Emergency space blankets provide a false sense of security

TRADITIONAL MOUNTAINEERING ™
www.TraditionalMountaineering.org ™ and also www.AlpineMountaineering.org ™

TraditionalMountaineering Logo - representing the shared
companionship of the Climb ™

Search this site!
Read more:
Emergency Bivy Sack:

Emergency space blankets provide a false sense of security!

We were snowshoeing the other day with folks who did not seem to be Prepared for an adventure even a couple of miles back into the snowbound wilderness.
They each used a small "fanny pack". I asked them what they would do to keep warm during an emergency stop and stranding - to care for an injured companion, or if the weather closed down to hard wind driven rain or snow and familiar trails and ways disappeared.

All of them said they carried a "space blanket" to keep them warm. There-in lies the danger! Emergency space blankets provide a false sense of security!

I have heard this claim before, that "a space blanket provides warmth". I have always understood that the term "space blanket" is a misnomer: the thin plastic sheet is neither a miracle material nor a blanket! "Blankets", thick or thin, trap air for insulation. The thicker the blanket the higher the insulation rating. (Blankets do not add heat unless the blanket is warmed, as in an Emergency Room. Warmth must be added, under the insulation).

It is well known that body heat is lost in 5 specific ways: Convection, Conduction, Radiation, Evaporation and Respiration. Excessive body heat loss leads quickly to hypothermia.

The thin shiny plastic sheet (heavily advertized as an "Emergency Space Blanket") has no insulating qualities, indeed, the plastic immediately becomes as cold as the rain or snow or the wind blown air and will immediately conduct that cold through wet clothing to the human body. Also, it is almost impossible to close out the cold wind. I learned this personally, at the finish line of the New York Marathon in 1979.

If you lie down on a plastic space blanket placed on the snow, the cold will immediately be conducted directly to your compressed clothing. If your clothing is damp or worse - wet to the skin, you might as well lie down in an ice cold mountain stream.

An inexpensive alternative to the metalized Space Blanket, is a common heavy duty trash bag (or two).

You must carry extra insulating clothing layers and an insulating ensolite pad in a lite day pack designed for the Season, the forecast weather and the individual trip!
Learn about individual "clothing insulation layers" and "shelter" listed in the Ten Essential Systems.

The five ways that heat is lost by the body:

Convection
When wind blows against the skin or wet clothing, it helps speed up the processes of evaporation, making the person become much colder (often described as the wind chill factor). Technical under-layers that "keep the skin dry" help block this factor. A mandatory waterproof-breathable (Gore-Tex) outer layer breaths perspiration and keeps your insulating layers dry.

Conduction
Heat will be lost through contact with wet surfaces at a lower temperature than that of the body. Technical under-layers that "keep the skin dry" help block this factor. A mandatory waterproof-breathable (Gore-Tex) outer layer breaths perspiration and keeps your insulating layers dry. You must carry a lite 6 oz. insulating pad to shelter on snow or wet ground.

Radiation
Heat is lost through radiation from all over the body. This is the least significant factor. Your clothing, hats and gloves help block radiation.

Evaporation
Heat is lost through the body's natural cooling system (perspiration) which evaporates from the skin and clothing wet with sweat, melted snow, rain, stream crossings and more. Technical under-layers that "keep the skin dry" help block this factor. A Gore-Tex waterproof-breathable outer layer breaths perspiration and keeps your insulating layers dry

Respiration
The only other way in which heat is lost is through respiration (breathing), and this should be attended by covering the mouth and nose area with a wool scarf or a special mask. You may need to stop, stay in one sheltered place and limit your heat loss from heavy breathing while trying to find your way.

The English manufacturer of the Kelvalite 'Life Emergency Blanket' describes how to use their product:

IMPORTANT
"It should be stressed here that the 'Life' Emergency Blanket should be used in conjunction with any other hypothermia/core warming treatments if available - however, in an emergency situation the 'Life' Blanket is far more efficient than traditional cloth or synthetic blankets.

Using the 'Life' Emergency Blanket couldn't be easier - just unfold and wrap around the patient.

To be at its most effective however, the points below should be observed:

Unfold the blanket completely and lay flat on the ground, preferably on as warm, dry and insulated a surface as possible.

Lay the patient on the blanket, leaving about 12 inches of blanket overlapping at the 'feet' end. The blanket is most effective when used directly next to the skin - if required material blankets may be wrapped on the outside of the Emergency Blanket.

Fold the end of the blanket over the feet, and bring the two sides up and over to overlap at the top.

If possible secure the blanket with some tape - the better the seal the more efficient the blanket will be.

Do not wrap too tightly as the air which is trapped contributes to the insulation - see Technical Information section for further details.

Be sure that the feet, hands and as much of the head as possible are covered. If necessary use another blanket (or a child size one) to wrap around the top of the head, leaving the nose and mouth uncovered.

Use an inhalation re-warming unit if available, or cover the mouth and nose with wool or a handkerchief to help slow down heat loss through respiration.

The patient may complain of feeling clammy or uncomfortable - this is perfectly normal and simply means that the blanket is working. The closed 'tube' means that moisture cannot escape - this causes the humidity levels next to the skin to increase, and slows down the patient's natural cooling system (evaporation via perspiration)."

Harrison Insulating Systems

The Thermo-lite "Emergency Bivvy Sack" is the shelter that we suggest:

My friends and I each carry an Essential insulating 12 x 12 inch "butt pad" in our daypacks year around and in winter we also carry a larger 24 x 48 inch Essential insulating pad such as the Cascades Designs Ridge Rest Short (inexpensive and only 6 oz.) secured to the outside of each person's winter pack to insulate us from the snow while sitting for lunch or sheltering while stranded. Our winter day packs are large enough to carry extra hats and gloves and enough extra insulating clothing layers including puffy down or pile jackets (and sometimes down pants) and our light Gore-Tex hooded jacket and side zip pants to keep us protected from wind and wet.

A plastic space blanket is not a substitute for your winter layers including puffy synthetic or down insulation and Gore-Tex clothing used with the Emergency Bivy Sack described below.
An inexpensive basic alternative to an expensive space blanket for each member of a family group as suggested in Backpacker Magazine, by Search and Rescue Volunteers and some "survivalists", is a heavy gage plastic trash bag. (A packaged plastic space blanket can be carried in your Group First Aid Kit to provide a clean area on which to tend an injured companion.)

My friends and I each carry year-around, a 9 oz. "Emergency Thermo-Lite 2.0 Bivvy Sack" sold by Adventure Medical Kits for about $30.00
This is a "bivy bag" made from a "tough, four-ply, waterproof, windproof fabric (Thermo-Lite®) sandwich", which is designed (when used with a light 6 oz. insulating pad), to keep the cold outside layer from conducting to the inside layer. It is designed to prevent Convection, Conduction, Radiation, and Evaporation. We will breath through our wool scarves and calm our breathing to limit heat loss from Respiration while we wait probable hours for Rescuers. The Thermo-Lite® Emergency Bivvy Sack is sold through the REI Website (ship free and pick up at REI in Bend) and at larger REI stores nationwide.
Un-attributed material Copyright© 2004 - 2012 by Robert Speik. All Rights Reserved.

(This 9 oz. Essential Shelter is about the size of a soft, chubby one quart Nalgene bottle)

The new Thermo-lite Escape Bivvy starts shipping to stores in January, 2012

"The Escape Bivvy is nothing less than a revolution in backcountry shelters. The complaint with most ultralight emergency shelters is the same: condensation builds up inside as you get warm, leaving your clothes soaking wet. With the Escape Bivvy, condensation is no longer an issue, and you never again have to choose between staying dry and staying warm. The proprietary fabric lets moisture escape at the same time that it keeps rain, snow, and wind on the outside – all while reflecting your body heat back to you. Waterproof seams plus a drawstring hood closure and side zip mean you can seal out the elements entirely or use the bivvy like a traditional sleeping bag, and the high-visibility orange exterior makes it easy for rescuers to spot you even in areas with high tree cover." Cost about $50.00, weight about 9 oz.

"Adventure Medical Kits was raising money for NOLS scholarships at Outdoor Retailers Winter Market with a deal for their new SOL Escape Bivvy. Already turning heads at the show and winning awards, the bivvy will go on sale later this year."

(Not yet in my local stores)

http://www.adventuremedicalkits.com/product.php?product=263&catname=Shelter&prodname=Escape%20Bivvy%20-%20Shipping%20January%202012!

Cascade Designs/MSR E-Bivy is another Emergency Shelter option!

Carried summer and winter, tucked in a little corner in the bottom of your day or summit pack, this answer (with an insulating 6 oz. pad) to the 10th Essential System, "SHELTER", should last a lifetime of adventures.

"The diminutive, weather-resistant E-Bivy sack adds the ideal amount of protection for wide range of situations without adding much to your pack. It will block wind, dew, spindrift and even light precipitation, adding valuable warmth and comfort when used under tarps, on open bivies and for winter camping. It can also be tossed into a pack lid on any trip, providing essential protection for an unplanned night in the hills.
Highly Breathable: Increased fabric breathability minimizes internal condensation. Versatile: Silnylon top and tough, DuraShield™-coated waterproof bottom protect from dew, frost, wind and light precipitation while adding warmth to any sleep system.
Compact: Weighs a mere .25 kg (9 oz.) and packs ultra-small."

One other 9 oz. Emergency Shelter Bivy option is this $99.00 Cascades Designs "E-Bivy"