I hadn't seen or heard of this here before, but I really like the idea.

Solatec Survival Vest

This could be a great little addition to a survival kit for cold weather. Having that pocket of air around your midsection ought to be a lot like a down vest.

Anyways, it looks worth it to me.

Interesting idea.

When dead air spaces are above about 1/8" they lose insulating
ability due to air movement. That is why you need some down etc.
between the outer barriers. Something like the blizzard bag in
a vest would probably work better.

Really, I always figured that so long as the captive air didn't have an efficient means of conductive heat loss to ambient, it would retain it's insulating characteristics. I am also thinking that the reflective reabsorption from the outer layer will make the air chambers virtually effective insulators.

Now if the outer layer were wet cloth, I would expect that the vest would be worthless, as the thermocouple to ambient would be way too efficient.

One would think that, given it's construction characteristics, the thermocouple from the body side of the vest would be very efficient in comparison, thus allowing for a much higher entropy because the air in the chambers is captive and the weak thermocouple doesn't promote any closed cell loss.

In an open cell environment, such as sleeping bags or breathable down vests, the 1/8" captivity seems much more realistic. Loft becomes a factor because air movement is restricted/diminished due to macropore resistance which limits convective air flow, but in a closed cell system, I always figured the lack of any air flow fairly negated any convective heat transfer to ambient, except for a negligible amount due to the skin effect of the structure itself.

Kinda like when I stuff myself into one of them emergency survival bags and bind up the opening real good, leaving just a breathing tube sticking out, then proceed to overheat in about 3 minutes.

The vest would be good at blocking direct conductive heat loss but if the air pockets were big enough heat can still be lost via convection. Even if the air is 'still' the act of the air heating, rising, cooling, falling, expanding, and contracting will move it enough inside the pockets to dissipate some heat. Looks like the vest has a lot of air chambers and that will help a great deal at preventing air movement.

Better than a straight sheet of space blanket though as far as insulation goes.

This is intriguing.Maybe an entire suit could be devised using bird flu suits as a base:
http://www.sciplus.com/category.cfm/subsection/4
8044 LG. FLU SUIT
$5.95 EACH
Take two of them, nest them, and seal the holes with elastic, and inflate the space between with a flexible straw.
I suppose if convective loss due to open space in the air chambers is an issue, you could kill birds, pluck them, and stuff the down into the chambers...

What he said.....

Its an interesting idea, however for the same price (used) slightly bigger bulk, why not just pack a fleece or down vest?

Teacher

Just get a few feet of Reflextix Insulation, cut a keyhole head opening in the middle, pull it over your head and stick the sides together with duct tape.

Reusable. Cheap. Can also be used as a stadium pad.

Sue

I picked up a couple of these last fall and kept one in the vehicle kit over the winter, while the other one resides in my primary BoB year round.

They are intended for single use, although the instructions indicate that they can actually be deflated and reused if you are careful and take your time. Since I can't seem to even repack an AMK Heatsheet back to it's original size, I haven't tried inflating one of these to check out its real world performance (the concept seems valid enough though). Speaking of Heatsheets, it's very similar in construction (and therefore noise level) as opposed to the old noisy Mylar space blankets.


Good luck finding a fleece or down vest that weighs less than 53g and packs smaller than a deck of playing cards.

I was out camping a few weeks ago and the overnight temperature dropped to 25°F (about as cold as it ever gets around here) and I was >>>||<<< close to throwing one of these on inside the sleeping bag.

Jim

Hmm, mixed feelings about this.

There may be some value to this in generally mild climates, where you wouldn't normally expect to get cold. So in the short term, maybe it's better than nothing.

Moisture retention is the big consideration. Really, this is a space blanket with a plastic bag draped over top. If you wear this over your clothing, you will quickly become damp and then wet from normal insensible perspiration. And then you will really be cold. So if you wear it, put it close to the skin, and live with the clammy feeling. If you're actively walking, it won't ventilate, and the moisture build up will happen even faster.

Besides that, I don't like the "disposable" aspect. And what's the shelf live in a package? Better off, I think, with the reflective bubble wrap that Susan suggested. That is true survival stuff.

My vote? Not worth the money. Carry a fleece cap and an oversize trash bag instead.

Some anecdotal comparison:

Back in 03 I went through my hazmat level a certification. We had to put on an enclosed tyvek suit (not level A, but close) with an SCBA inside. This was in the middle of winter, and we were experiencing a frigid arctic blast at the time. Outside temps were around 15 degrees F, and winds out of the northeaast at about 15 mph. After we were suited up we had to walk from the classroom to the simulator, maybe 200 yards. Our escorts are wearing the full complement of winter gear; parka, watch cap, gloves, boots. Inside the tyvek suit, I am wearing a t shirt, jeans, and my work boots.

Now the tyvek suits are notorious for not venting well, and I am an air hog with an SCBA (I consume about twice as much as as the average joe over time, go figure), so my suit is inflating some (the suit vents better once a little pressure differential is established). Anyways, the whole time I am walking across the parking lot, I notice that the temp inside that suit is still warm enough that I am perspiring. Now once we get into the simulator and start crawling around I am sweating and getting uncomfortably hot. Once the simulation is over, I punch the bypass valve on the SCBA to get the cold compressed air blowing on my face continuously to help me cool down. After I have doffed the suit, I take a step outside, and my warm sweaty body jolts from the frigid cold blast.

So I am thinking that way more than 1/8 inch of air gap between my body and the suit did a lot to keep me insulated from the cold and trapped a lot of body heat in the process. From an experiential point of view, I'd say the vest must be similar.

Even though the air in the vest can circulate more or less freely within the individual chambers, I don't think convective loss is going to be a factor because the circulating air doesn't have a good thermocouple to the outer layer of the vest, based on how the air in that tyvek suit stayed so toasty warm. If the outer layer of the vest were metal or wet fabric then probably convective loss would be an issue because the circulating air in the chamber would be in contact with a much better thermocouple.

Come to think of it, once my suit inflated, I did get cold spots where my skin came into direct contact with the tyvek, such as at my elbows and wrists when I had to bend my arms. I suppose that, had the suit not inflated as it did, I might've ended up much cooler than I was. That seems counter-intuitive to the 1/8" principle.

Sounds like a job for mythbusters to me.

I've got to think that a vest like this would add warmth, but how much I have no clue about.

Seems like something made out of material similar to a sleeping pad might be a winner. I doubt it would capable of being packed into something the size of a deck of cards, but it should be fairly small.

Interesting product, and good discussion to be sure. I stumbled across this vest recently (online) and was thinking that while it had to be more insulative than a plain space blanket, the convective losses would steal a lot of heat, especially when you're sitting still. However Benjammin's experiences seem to refute that to a degree.

I agree that you'd be hard pressed to find a fleece vest that weighs this little & packs this small.

Like many things on the market, I wish I could wave a magic wand and make tweaks to what is a reasonably promising design:

- construct it from the same quiet, strong plastic as HeatSheets
- add just a little baffling of some kind to the chambers
- put a little bungy cord/elastic around the arm holes & bottom hem to keep warm air from being pumped out each time you move

Of course, by the time you did all this it would weigh twice as much and cost $30.

Here is the product's webpage & it has some more details. Here is a detailed review from Backpacking Light that I think is freely available without a subscription.

There's a lot of heat energy in the evaporated water that makes up sensible perspiration (sweating) and insensible perspiration (which happens continously from our skin).

If you can trap that evaporated water, you create a warm, moist envelope around yourself. That's why some hardcore outdoorspeople put sealed vapour barriers inside their sleeping bags to get more warmth for less weight.

But unless you have insulation outside of the vapour barrier, that warmth would be very short term. The determining factor would be your activity level. If you slow down, after your clothes have become saturated with moisture, convection and conduction would catch up with you. And then you would be really cold.

The Tyvek suit is a good example; the same would apply to oft-repeated advice of "crawl into an oversize trash bag and you'll be fine." I'd hate to spend a night like that; without additional insulation, it would be miserable.

The vest under discussion is a bit different, in that the air chambers won't contain moisture except that from your breath while inflating. If the wearer is moderately active, it will reflect and retain some warmth, though convection losses will be much more than an insulated garment. I think the most effective use would still be to wear it next to the skin, and put any other clothing over top.

This seems reasonable to me. I am thinking that directly on the skin might be too uncomfortable, but over the top of a synthetic t shirt (like the under-armor type), then with the remaining clothing outside of the vest it should be pretty effective.

From my experiences in Iraq with battle armor, I can say that everything under the vest is going to get wet from perspiration collecting, but the arm, torso and neck openings should serve to mitigate that under moderate conditions. A good synthetic undergarment will help to keep the comfort level up, without retaining too much moisture I would hope. You'll probably end up with fairly wet armpits if you exert yourself in this vest at all.

Step one is to get one of these vests, step two will be to find a cold place to try it out in (looks like I am gonna have to invest in a big chest freezer next).

I would like to see some thermal imaging studies performed before I would count on this product do what the manufacture’s claims. This product cannot fully encapsulate you the way you can with the heatsheet (covering one’s head and trunk, effectively blocking the wind – convection loss). We have discussed the use of an inflatable air mattress in terms of heat retention, which they do not, although heat loss is through conduction (contact with the ground) more then from radiation or convection loss that the vest would theoretically block. It seems the claim to fame is that you are inflating the chambers with air warmed by the body via one’s breath and that might have an initial warming effect, but as soon as the heat is transferred from the trapped air to the outside air, this short term benefit would be quickly lost. Trapped air with that degree of volume will still allow for body heat to be transferred from the body to the outside air as the chambers cool off and start robbing the body of heat. Is it better then nothing? Sure.

Pete

Here's another good review, with pics even:

Be Prepared To Survive Review

http://www.montane.co.uk/productdetails.php



Montane Jetstream Jacket

Weighs 75 grams and packs about the same size as an apple. Fits inside my small Snowpeak 300ml Titanium cup.



The breathable nylon shell material of the Jetstream jacket when worn can be stuffed and insulated with dry grass, heather, Cattail heads, shredded newspaper etc or anything else that can be used as an insulator to reduce convective heat loss in very cold environments. The Jetstream jacket is also remarkably warm in for its weight its own right, as it can cut down dramatically any convective heat loss being windproof and somewhat weather/water resistant but still remaining a MVP material. This allows the air space directly above the skin and between the undergarments to remain dry and thereby stops the undergarments from wetting out and stopping excessive evaporative cooling of the skin.

I would say a large garbage bag would be as warm as that vest
and would provide better coverage from the elements. A tyvek
suit, especially the coated models would be better yet.

The air mattress comparison is a great one.

Micro convection larger voids in still air occurs whether sealed off or not in larger voids. Why do you put fiberglass in your walls, or special gas in thermo's.

This vest is stopping heat loss by convection, evaporation, helps in the short term with stopping some wetting of the clothes underneath by rain or snow and so is useful, but the air pockets are kinda gimmicky without some method of stopping internal convection.

I would take a trash bag over that vest given the choice, even if they were the same price, due to the better coverage of the garbage
bag. You can make a small tent from a garbage bag and even use a heat source under the hem as the cavers do. I carry one in the lining of my climbing helmet.

Okay, then I guess I am going to have to find a decent garbage bag and buy one of these vests and do a comparison.

Now the question is, where will I find a place in central Florida cold enough to test them both?

Looks like I am still going to have to purchase a big chest freezer too.

If you were in NYC, I'd send you into a "Western Beef," which is a grocery chain. Each one has a refriegerated section that you walk into with the shopping cart. Something like that or any meat locker should do the trick. Maybe you should make friends with a butcher.

Say, that gives me an idea. Costco has a walk in chiller for it's produce section. I wonder if they'd think me peculiar were I to stroll in with the vest and a garbage bag and proceed to don and doff them in succession.

The tester, in my opinion did not test the vest as stand-alone survival garment and changed the parameters by placing his coat over the vest. If used in combination with an over-garment, then yes it should increase the insulation value of either the vest or coat by itself. I would like to see if he still felt it worked without his overcoat. It is unclear to me what “I hung around in the woods for awhile” means in terms of real time and would like to see a timed study with thermal imaging and/or temperature probes while standing, sitting or laying around for a significant period of time (spend the night out), as one might encounter during a real survival situation. This product may in fact work and be a valuable asset; I just do not see the testing/data to support the claims.

Pete

Ever wear a float coat? It's a windbreaker built around a pfd. During our annual ice rescue classes this Jan I was wearing one on the quite windy shores of Lake Champlain and was the warmest I have ever been on the ice!

A float coat is specifically designed not only to provide flotation but also thermal protection. An ice rescue suit provides even more thermal protection as one would expect. I took my Ice Rescue Instructor class in Georgetown, Colorado a couple of years ago in the month of February and despite the wind and sub-freezing temperatures, I was quite warm in my Mustang Ice Rescue Commander suit for the 8 hours plus we were out on the ice. In one of the scenarios, I was in the water for 30 minutes before I even began to feel the cold and could have easily lasted for another 1 hour plus.

Pete

The instructions on the packaging state "For maximum warmth wear AeroVest on top of your shirt and under your jacket. Inflate after your jacket is on."

I can't really envision a realistic scenario where you would require an AeroVest and wouldn't already have a jacket or waterproof shell on.

Jim

If you go to the web site benjammin listed in his first post or the AeroVest site, you will see all of the users are weaning the vest without a jacket. Now I realize this is primarily for sales reasons, but still in my humble opinion somewhat misleading.

I can think of a several scenarios (our team has rescued dozen of people without jackets) where one is without a useable outer jacket (not smart but still the reality). How many times have we discussed someone or groups of people just going out for a day’s hike, it’s warm, so they did not bring along a jacket. The weather changes or they get caught spending the night in the woods without proper clothing. Perhaps they did wear or bring a jacket (likely cotton or lightweight nylon) and got it wet, the insulating properties are lost or worse are resulting in additional heat loss due to convection. The question remains, is this vest effective as a stand-alone piece of equipment or not?

A heatsheet will provide greater body surface coverage, better convection heat loss protection, is much cheaper and packs down to the same small size. You can place a slit in the heatsheet and use it as poncho, use it as blanket, wind-block, a heat reflector, vapor barrier, lean-to or A-frame shelter just a much more versatile piece of equipment.

Pete

Yesterday an aquaintance warned me to never use a space blanket because they go up in flames like they're made of gasoline if a fire or spark hits them...I can't confirm that but it seems dangerous...and if it's true, you definately want to wear it UNDER your jacket.

Very real possibility, as almost any synthetic will burn/melt. Caution around fire is always warranted, regardless of what one is wearning.

Pete

Caution with fire is always wise, but with synthetics it becomes more important. Most synthetics originate with petrochemicals, hence a tendency to burn and/or melt. However, it is tough to beat them in terms of weight to the amount of insulation they can provide. It's one of the tradeoffs you need to consider when picking your clothes and gear.

My bet is that few go outside for very long without synthetics. Imagine going camping with no synthetics; no synthetic tent material - canvas, a canvas pack, wool or cotton or leather clothing, silk or cotton underwear, wool blankets, no paracord - marline or manilla, etc.

I can imagine camping with no synthetics; our family has for almost 20 years participated in 18thcen living history events.

Pete

Unfortunately it's more expensive to do things the 'old ways' these days. I'd love to go into the bush like Nessmuk did back in the day and live there for periods at a time...but that won't pay bills and an ultralight hand made canoe will set you back a couple thousand bucks or more...not to mention that generations of living in the city have left me completely unequipped to do it confidently...but we're working on that one slowly but surely.

Pete,

I'm with Hacksaw in that I am not equipped to head off into the woods and without some advantages of modern chemistry.

I would guess however that the gear used during such history events is of a much different weight than that which gets stuffed into my back pack. I like and use bedding from natural materials at home, but it would fill my entire pack.

Pete,

I didn't intend to imply there aren't a bizzilion idiots walking around in the woods without a jacket available, but very few if any of these morons would have the foresight to be prepared enough to be carrying an AeroVest.

My post should have been clearer -- chances are pretty good that if you're prepared enough to carry an AeroVest, you have the proper clothes (i.e. a jacket) with you as well.

Jim

I took the standard class from the group you're speaking of(can't think of the name right now, maybe dive Rescue International?) The Ice Commander suit is fantastic! I started off in '89 using actual survival suits not really made for rescuers but it was a start. I definately prefer the Ice Commander!

I decided to check out the degree of flammability of the typical survival Mylar blanket, the AMK Heatsheet and a plastic shopping bag. This was a “down and dirty experiment” so there may be some less then desirable variables, although I tried my best to keep them to a minimum.

I had 3 silver Mylar blankets from different manufactures/supplies and are as follows (with information on flammability if noted on the package):

Dukal Corporation
119 Lafayette Drive
Syosset, NY 11791
Made in China

HEAT –REFLECTIVE SURVIVAL WRAP
“Warning: Do not expose to direct flame”

S.O.S.
Food Lab, Inc.
9399 N.W. 13th St.
Miami, FL 33172
Made in USA

EMERGENCY BLANKET
“WARNING: Passes Flammable Fabrics Act Test COMM PRAC 1610, but will burn if ignited.
KEEP AWAY FROM ALL OPEN FLAME”

The Coleman Company, Inc.
3600N. Hydraulic
Wichita, KS 67219
Made in China

EMERGENCY BLANKET
No warning on packaging

Adventure Medical Kits
P.O. Box 43309
Oakland, CA 94624

Heatsheets
Survival Blanket
No warning on packaging

Plastic Shopping Bag to act as a control

For each mini-experiment, I used a 1” X 1” piece of the blanket
For the flame source, I used a laboratory burner (open flame), with a pilot light using natural gas.

Experiment #1: Holding a 1” square piece of blanket/blanket, moving at a slow steady pace from 6” out from the flame towards the flame. I noted distance where the material started to deform/melt and at what point it ignited.

Experiment #2: To emulate a growing ember, a glowing red wooden applicator stick was applied directly to a 1” square piece of blanket/bag. I noted what occurred.

Experiment #3: Holding a 1” square piece of blanket/bag, moving at a slow steady pace from 6” out from the pilot light towards the pilot flame. I noted distance where the material started to deform/melt and at what point it ignited.


Results:

Experiment #1:

All 3 Mylar blankets were observed to have the same characteristics – Deformity/melting occurred between ½” and ¼” from the flame and ignition occurred when the blanket came into contact with the flame. No dripping of the ignited material was observed.

AMK Heatsheet – Deformity/melting occurred between ½” and ¼” from the flame and ignition occurred when the blanket came into contact with the flame. Minor dripping of the ignited material was observed.

Plastic Shopping Bag - Deformity/melting occurred between ½” and ¼” from the flame and ignition occurred when the bag came into contact with the flame. Major dripping of the ignited material was observed.

Experiment #2:

All 3 Mylar blankets were observed to have the same characteristics – Deformity/melting was observed only when the glowing wooden applicator stick came into direct contact with the blanket. No ignition or dripping was observed.

AMK Heatsheet - Deformity/melting was observed only when the glowing wooden applicator stick came into direct contact with the blanket. No ignition or dripping was observed.

Plastic Shopping Bag - Deformity/melting was observed only when the glowing wooden applicator stick came into direct contact with the bag. No ignition or dripping was observed.

Experiment #3:

The same observations as in Experiment #1 were repeated.

Comments:

All of the tested materials have the potential to ignite, in this series of mini-experiments, ignition of the material require direct contact with an open flame.

The Mylar blankets did not drip molten material when ignited, the Heatsheet did to a minor degree and the plastic shopping bag did drip significant amounts (realtive to the other tested items) of molten plastic. Keep in mind these tests only involved 1 square inch of material.

None of the tested material ignited with direct contact from a growing red wooden applicator stick.

Users of these products should be cautious when around open flames and should avoid direct contact with an open flame. With care, the products should be relatively safe near open flames and the possibility exists that if burning embers should fall on the products, burns may occur, but no evidence of ignition of the products were noted.

Pete

Great work Pete!

I don't know that dripping is as much of an issue is melting onto your skin.

Maybe Blast will know.... ;-)

Sue

Dripping becomes more of an issue with spreading the fire I believe.