Vapour Barrier Clothing

Posted by: Rick

Vapour Barrier Clothing - 10/16/08 05:35 PM

This is not an entirely new concept to me. But the effectiveness, products, techniques, etc is.
I am a big sweeter. I mean I can get drenched from my own perspiration even in the coldest of temperatures. I've learned to deal with this, to some extent, with effective layering. Often times wearing the lightest of base layers with a wind shirt top. When I stop I immediately don a parka to stay warm. This works, but leaves me with wet base layers. These have to be dried on multi day trips. Workable, but certainly not ideal.
So, is vapour barrier clothing something worth looking into to for winter treks? Does anyone use this technique? What products are worth looking at? What, if any thing, is the down side?

AATIA
Posted by: alanwenker

Re: Vapour Barrier Clothing - 10/16/08 05:48 PM

I've been wanting to experiment with vb clothing but to date have not done so, other than socks and a vbl in my bag. I've read in the past that one's legs develop so much sweat that vb pants just get too hot. Like many things, I would love to try it but don't want to shell out cash for the goods if I'm not certain I will like it. Maybe someday I come upon a cheap option for experimenting.
Posted by: phat

Re: Vapour Barrier Clothing - 10/16/08 07:39 PM


The only things I've ever tried are on my feet - I've used vbl socks made of silnylon to deal with my feet sweating and wetting out boot liners in very cold weather. Those have been very effective and I can stand them. I think I bought mine at campers village, and they don't have a brand on them that I can remember. I also sewed a pair from scrap.

I've also tried a (borrowed) VBL bag liner - and I simply can't deal with it <img src="/forums/images/graemlins/smile.gif" alt="" />

Judging by how effective they are on my sweaty feet in my kamik boots, I think the technique would probably work fine as long as you can stand stewing in your own juices.
Posted by: TomD

Re: Vapour Barrier Clothing - 10/16/08 10:01 PM

There should be some discussions about vbl in the archives. Stephenson (not Bill, but the tentmaker) is a big proponent of vbl and there is a fair amount of into on using it on their website. They sell vbl clothes and bag liners.
http://www.warmlite.com/start.htm#anchor28960

My understanding is that vbl is for use in very cold, very dry weather and the purpose is to keep moisture in so you don't chill from evaporation. It also keeps your bag from getting wet from sweating at night, your basic evaporation into the bag. Read Stephenson's lengthy explanation on their website.

It must work, but the idea of waking up wet, just doesn't appeal to me. Then again, I'm not out in -40C weather either, so maybe then, I'd feel differently (no pun intended). <img src="/forums/images/graemlins/wink.gif" alt="" />
Posted by: ringtail

Re: Vapour Barrier Clothing - 10/17/08 07:19 AM

Rick,

I have been on about a 5 year journey to learn vb cothes.

Start off with a cheap pvc rainsuit that you use in your sleeping bag. If you like the technique then the Stephenson vb clothes are good. On a sunny day I skied with only the vb shirt on top, but sweat pooled at my elbows (TMI?).

I also can ski/snowshoe in an expedition weight top and a windshirt down to about 20. However, I hike with an experienced guy that always seems to have on one more layer than me. YMMV.

IMO it is a worthwhile journey.
Posted by: TomD

Re: Vapour Barrier Clothing - 10/17/08 12:22 PM

Food, Here is what I don't understand about vbl usage. I read Stephenson's explanation of how it works on their website, but it seems to me that if you are skiing or snowshoeing and generating a lot of heat, then you would want to be wearing something breatheable so the heat could escape, not what looks like an industrial strength plastic bag.

Once you stop, then the heat production slows down after a few minutes and therefore, you put on a jacket of some sort and maybe a hat to insulate you and retain the lower level of heat you are generating.

But, if you are wearing a vbl shirt or pants, for example, while skiing, doesn't all of the heat and sweat you generate stay inside the jacket or pants and you get hot and wet? Isn't the point of breatheable fabrics like eVent or Gore-tex to prevent that from happening?

I can see the vbl theory working at night, but it just doesn't make sense to me if you are moving and generating heat and sweat.

I have spent a lot of time underwater in a wetsuit, so I know how that works. Stand around in one in the hot sun for a few minutes and your temperature climbs quickly. To me, a vbl works about the same way, except in a wetsuit, you are actually heating up a thin layer of water that keep you warm because it is insulated from the water surrounding you.

The eVent/Gore-tex theory vs. vbl theory can't both be right, can they?

What am I missing here?
Posted by: phat

Re: Vapour Barrier Clothing - 10/17/08 01:44 PM

Quote:

The eVent/Gore-tex theory vs. vbl theory can't both be right, can they?

What am I missing here?


What you're missing here is that in colder climates, like Rick and I are used to, when you go out in winter if you sweat and you can't get the layer off, you die.

I'm all for breathable and the like. the problem becomes one of when you stop. assume for a minute you know you're not going to get rained and snowed on, so you needn't worry about that.
You still have the issue that doing any kind of exercise in snow you simply sweat. some of us
profusey. Now at milder temps, I don't worry too much, I may sweat the heck out of a base layer and fleece, then stop and shelter myself from the wind, throw a layer on and allow it to dry from my body heat. This works pretty good until you get really really sub zero like down in the low -teens and -20 centigrades. Once I get down that cold I find I can't generate enough body heat to dry that sweaty layer in time without getting real cold real fast, or cover up with a big insulating layer, that at those temps, you're then *frosting up* with the sweat evaporating out of your wet base - wetting out a down parka because you're wearing it over a sweaty base to keep from freezing really sucks.

It's never as absolute as it sounds, you can get a little moist and be fine. but a heavy sweat
and sopping clothing at canadian winter temps is a serious liability. You can carry an extra
change, but then what do you do with the wet stuff? - if you have a hot tent or a fire you can dry it off, alternatively, you just need to be real careful *not* to sweat a lot, which isn't a lot of fun or
very easy sometimes.

Now my personal tactic is a combo of both, I take it a bit easy and/or I do have an extra set of
base layers with me in winter that when stopping I can full change, and build a fire to get the old
set reasonably dry again - in my climate (extremely dry when it's cold) it doesn't take too much.

You're totally right in that it's just like a wet suit - it is. I personally don't like the feel of VBL liners in bags, but I've definatley used VBL socks (they're wonderful, if clammy) and see the attraction
to trying vbl clothing. The alternative is constantly trying to dry out wet stuff and having to
change. A gore tex outer does not help. freezing temps change everything, especially once the
water vapor will freeze to frost *below* the layer of the gortex - won't happen much in milder
temps (even below freezing) but once you're insulated enough to be stationary at -20 you better believe it does.
Posted by: ringtail

Re: Vapour Barrier Clothing - 10/17/08 02:14 PM

Tom,

Below freezing I prefer nylon rather than eVent and Gor*Tex. Nylon is waterproof when water is in the solid state. Those fabrics perform best in the 50 to 10 range.

Snow above about 20 produces a strange situation. While I can stay warm with just an expedition top and wind shirt the outside of the windshirt is above freezing thus snow melts and wets-out the windshirt. What works for me is the vb shirt, a silk weight top and silnylon pullover. It is counterintuitive for me to insulate my shell from my body heat to keep it dry.

The biggest problem with overheating while wearing vb clothes is that your underwear gets wet. IF you have a stable level of exertion then you can tweak your layers so that you do not overheat. About the only time this happens for me is training.

Summary: I use vb only while training or sleeping. I think that if you are going to use it as emergency gear then you need to learn to use it. If you layer effectivly then you can wear everything in your pack at the same time. Vb clothes are a lot of warmth for very little weight.
Posted by: TomD

Re: Vapour Barrier Clothing - 10/17/08 03:48 PM

Thanks guys. The Stephenson stuff has some kind of "fuzzy" coating on it, whatever that is supposed to be. so it feels better than plain plastic.

I haven't been out in Canadian cold weather, so that makes a big difference. In Yosemite, in daytime with the sun out, it can be above freezing and at night, about 10-15F.

I don't seem to sweat all that much at night, so my bag doesn't seem wet to me at all in the morning. I've read about bags getting soaked from the inside, so maybe a vbl liner between a silk liner and the bag might work to keep that from happening.
Posted by: Rick

Re: Vapour Barrier Clothing - 10/17/08 04:14 PM

The WB clothing simply does does not work for me in the winter time.

Breaking trail in several feet of snow pulling a pulk is hard work - hence the sweat.

I don't like the idea of wearing a plastic bag, but if this technique keeps clothes dry, it deserves looking at.
Posted by: Rick

Re: Vapour Barrier Clothing - 10/17/08 04:19 PM

I think that you have summarized the situation quite nicely.

I have a hot tent, but quite frankly, I don't like it. I would much rather be outdoors.

As I see it, the object of the exercise, apart from being somewhat warmer with less clothing, is to keep clothing dry.
Posted by: Rick

Re: Vapour Barrier Clothing - 10/17/08 04:24 PM

Would a home sewn silnylon long sleeved jersey be a good place to start? In addition would a set of boxer style silnylon shorts be appropriate? Both lined with 100 wt fleece to absorb sweat.

Posted by: TomD

Re: Vapour Barrier Clothing - 10/17/08 04:57 PM

Rick, if you haven't done so already, take a look at Stephenson's website. You can see how they make their shirt. It has some kind of "fuzzy" stuff on the inside, but sounds like silnylon. It's not all that expensive. I only mention them because they make everything, including underwear and have a big explanation of how it's supposed to work.

Jack Stephenson was a pretty strange guy from what I gather from people who knew him (his son runs the company now). Kind of a "true believer" "my way or the highway" kind of guy like Ray Jardine is about his stuff. Be that as it may, at least they have a detailed explanation for why what they sell is made the way it is. I have no idea if they are right, but at least they give you something to think about.

www.warmlite.com

Here's another write-up on vbl by a guy back East who posts on VFTT and TTips and has a good website on bc skiing.
http://home.comcast.net/~pinnah/DirtbagPinner/vb.txt
Posted by: Paul

Re: Vapour Barrier Clothing - 10/17/08 08:56 PM

The one key thing about VBL's that you need to remember is that they are designed to prevent the loss of heat through "insensible" perspiration - that is, the perspiration that goes on all the time to keep your skin moist, as opposed to "sweating" or sensible perspiration, which is intended to cool you off. If you ar using VBL clothing and you are warm enough to "sweat", then you either have too much inslution over the VBL or the temperature is simply too warm for you to use it. For use during strenuous physical activity, it's tricky to keep that balance, and it has to be [Edited for inappropriate languge, please review forum policies for more information] cold if you are really exerting yourself. If you can maintain the balance, and not "sweat", then it can work well. But it seems that not many folks do use VBL clothing during strenuos activity (except for socks). It's much easier to maintain the proper balance of insulation while you are sedentary (especially sleeping), so that's why a lot more folks successfully use VB sleeping bag liners. But VBL clothing can be very useful for sleeping - as it's much easier to adjust your insulation by unzipping part of your sleeping bag, for instance if your wearing VBL clothing than if you are in a VB liner. Plus you can get up to pee without venting your VBL, and without risking a chill from the evaporation of moisture from the base layer you are likely wearing under the VBL.
Posted by: phat

Re: Vapour Barrier Clothing - 10/18/08 10:31 AM

Quote:
Would a home sewn silnylon long sleeved jersey be a good place to start? In addition would a set of boxer style silnylon shorts be appropriate? Both lined with 100 wt fleece to absorb sweat.



I'd bet if your silnylon sewing skills were up to it that would be a great way to try it out.

Not sure I'd put fleece underneath, just more crap to dry out. I'm thinking I do like I do with my socks, which is to put them over my polypro liners only (to keep from having foot problems,) and then put all the insulation outside, so me, if I were to do it (and I haven't) I'd put them over a comfortable poly base layer, and then everything overtop. When I get into camp, strip, and change our the base layer. Then you only have a poly base layer to switch out when sweaty, and that's almost always easy to dry out, or if you have to put it on moist to go the next day isn't so bad - particularly if you're in "wet suit mode" all day
anyway.

Just judging on how I do with silnylon VBL socks in boots anyway.. Geez you've almost
got me tempted to try it this winter, but I've always avoided it thanks to some horrid nights in a vbl bag liner (I'm a clausterphobic sleeper and a sweater..)
Posted by: Jimshaw

Re: Vapour Barrier Clothing - 10/18/08 01:13 PM

Rick
"I am a big sweeter"

I had heard that about you - a really sweet guy. <img src="/forums/images/graemlins/grin.gif" alt="" />

But NO - if you sweat, you will hate VB stuff. You will just cook in your own juices. If you do try it, take a complete set of dry breathable stuff to replace it with, and a towel.
jim <img src="/forums/images/graemlins/cool.gif" alt="" /> YMMV
Posted by: TomD

Re: Vapour Barrier Clothing - 10/18/08 02:20 PM

OK everyone, don't laugh, it just encourages him. <img src="/forums/images/graemlins/grin.gif" alt="" /> Hey, I love puns and even I avoided that one.

Now back to our regularly scheduled program. From what I read, I though the idea was that once you reached essentially 100 per cent humidity in the vbl bag, you'd stop sweating because the evaporation would stop. Not so?

The reason BWP fabrics work is based on the differential between higher temp and humidity inside a jacket (as an example) and the outside lower temp and humidity. Therefore, if you trap the humidity in the bag, there is no differential, therefore no more sweating.

I thought this is why Gore-tex or eVent doesn't really work in warm muggy weather and you may as well wear anything. I've worn nothing but shorts and a light wool pullover over Capilene in cold, light rainy weather (above freezing, like mid 40-50's and as long as you don't mind feeling a bit clammy as the wool wets out, you aren't really cold. Works for sheep.

JAK wears wool a lot, sound right to you?
Posted by: Rick

Re: Vapour Barrier Clothing - 10/18/08 03:01 PM

Wool - that is what is driving my querry.
I've started to switch to Merino. When this stuff gets wet, it takes forever to dry.
Posted by: Rick

Re: Vapour Barrier Clothing - 10/18/08 03:07 PM

You heard all the way over there how sweet I am? I wonder who amongst us is spreading these rumours? <img src="/forums/images/graemlins/shocked.gif" alt="" />
Posted by: Rick

Re: Vapour Barrier Clothing - 10/18/08 03:12 PM

Yes, you're right. A seperate poly layer under the VB jersey.
Posted by: phat

Re: Vapour Barrier Clothing - 10/18/08 04:52 PM

Quote:

The reason BWP fabrics work is based on the differential between higher temp and humidity inside a jacket (as an example) and the outside lower temp and humidity. Therefore, if you trap the humidity in the bag, there is no differential, therefore no more sweating.


BWP fabrics work great with liquid water where there is a humidity differential - Where I am, in Alberta, it is relatively dry most of the time - and BWP stuff works great in the summer. It has a rep of NOT working where it is very humid, so there is no differential between in and out.

However, the key difference here is *liquid* water. When it's only 5 or so degrees below freezing, I can still have my outside warm enough that the water will be going liquid through the membrane and it still works. much below that, by the time I'm insualated enough to not be dying, the outside of the gore-tex shell is well below freezing, which means liquid water ain't making it that far.... it's sitting in my insulation layer and freezing,
meaning I'm just wetting everything out.
Posted by: Jimshaw

Re: Vapour Barrier Clothing - 10/19/08 11:01 AM

TomD
There are a lot of theories and ideas about sweating. You could dip yourself in tar like they did on Mars to keep in the moisture. (Martian chronicles?)

But what I said is this - if you are trying something new, be sure to take the old gear along just in case the new gear fails for you. Often the usefulness of gear is dependent upon the user.
Jim <img src="/forums/images/graemlins/cool.gif" alt="" />
Posted by: ringtail

Re: Vapour Barrier Clothing - 10/19/08 12:05 PM

Rick,

phat beat me to it. I agree.
Posted by: ringtail

Re: Vapour Barrier Clothing - 10/19/08 12:08 PM

Paul,

Well said. The only thing I have to add is that if the vb clothes are to be multiple use items then you need to know how to use them while active. Vb clothes have a high "fiddle factor" when used while active.
Posted by: ringtail

Re: Vapour Barrier Clothing - 10/19/08 12:26 PM

Jim,

Notice I mentioned wet underwear and sweat pooling at my elbows. That is what makes vb clothes dangerous. You must adjust your insulation to match your activity level or adjust your activity level to match your insulation.

I try to thermoregulate with a minimum of layering. I use gloves, hats and jacket zippers for fine tuning.
Posted by: Earthling

Re: Vapour Barrier Clothing - 10/21/08 06:03 PM

Also Dick, the venting on the neck and hem of a VB shirt is not like a regular crewneck. If it was then it would'nt allow the approairate moisture level to build and work with the VB shirt. Definitely tech clothing for the gear fiddler amongst us. I had a tone of it in the 70's, and then lost much of it while moving in the 80's <img src="/forums/images/graemlins/tongue.gif" alt="" /> along with some of my LP collection <img src="/forums/images/graemlins/crazy.gif" alt="" />
Posted by: Cesar

Re: Vapour Barrier Clothing - 10/21/08 06:52 PM

quick question, how do you keep all your sweat from pouring out of your VBshirt onto the inside of your bag when you sit up. I guess the same goes for a VBLiner. You must need to get out carefully to keep from getting your bag wet. Also if its that cold that your body vapor can freeze in the down isn't it dangerous to unzip your bag and get out while wet at such low temps?
Posted by: Paul

Re: Vapour Barrier Clothing - 10/21/08 09:00 PM

Quote:


Now back to our regularly scheduled program. From what I read, I though the idea was that once you reached essentially 100 per cent humidity in the vbl bag, you'd stop sweating because the evaporation would stop. Not so?



Tom, this is the basic theory ONLYas it applies to "insensible" perspiration, and ONLY if you are at an equilibrium temperature - not hot, not "sweating". If you are hot, and your body is producing sweat to cool itself off, you will continue to do so regardless of the humidity. Again, it's all about managing the insulation to acheive that teperature equilibrium. Not too hard to do for sleeping or sitting, VERY hard to do while active.
Posted by: phat

Re: Vapour Barrier Clothing - 10/21/08 11:11 PM

Quote:
quick question, how do you keep all your sweat from pouring out of your VBshirt onto the inside of your bag when you sit up. I guess the same goes for a VBLiner. You must need to get out carefully to keep from getting your bag wet.

The idea with a VBL liner is *not* to sweat a lot in it. As for a VBL shirt, rick's not talking about wearing this in the bag - he's talking abou wearing it while walking in subzero.
Of course you have to be careful.

Quote:

Also if its that cold that your body vapor can freeze in the down isn't it dangerous to unzip your bag and get out while wet at such low temps?


If this were the case Canada would have never had human occupation because their bladders would have burst as we all steadfastly refused to leave our sleeping bags/buffalo robes. (then again I know I've had mornings that felt like that <img src="/forums/images/graemlins/smile.gif" alt="" />

it's not like you're sitting in the bag soaking - the problem is not that you are dripping - the thing you have to remember is this isn't that you're wet, it's just the natural water vapor that comes off your skin that freezes. Think about when you are in a single wall tent - you're not wet, but there's a bunch of moisture on the inside condensed in the tent. A lot came from your breathing, but some came from water coming right off your skin. In really nasty cold, that water doesn't go up and condense on your tent, it condenses, then freezes,
inside the sleeping bag. and if it's down that can really suck. The VBL doens't leave you sweaty (or it shouldn't in a bag) It should leave you comfortable, not dripping.

and as for getting out - you can always get out in such weather - you just can sit outside naked and wet with no chance of getting dry and warm.
Posted by: alanwenker

Re: Vapour Barrier Clothing - 10/22/08 08:43 AM

It's worth keeping in mind there is a large difference between getting out of one's bag and vbl with one's long underwear slightly damp (but warm) versus being totally sweat soaked with perspiration running down one's body and a pool of sweat inside the vbl. Frequently in vbl discussions I think the later image is what is conveyed, but in my case the former image is what I've experienced. I'm not referring to vb clothing worn when active, but mainly just in a sleeping mode where one is not moving around. I'm 75% certain I like the vbl for sleeping, but have to make time to experiment with vb shirts.
Posted by: whcobbs

Re: Vapour Barrier Clothing - 10/23/08 02:03 PM

Rick--
For several years I have used a hooded silnylon rainsuit as a vb suit for sleeping in subfreezing temps. Lightwt polypro longjohns go next to skin, then the rainsuit, then a stretch layer (pp/Lycra balaclava, power stretch ski suit or alternately polypro stretch bike jersey and winter polypro biker tights, then the insulated clothing ( Parka, insulated pants, finally a 2lb synthetic overbag. This scheme will dry out the damp clothing from the day's hike with body heat and dissipate the moisture through the bag. Do not try it with a down bag or with temps above freezing! Lightweight.
Walt
Posted by: OregonMouse

Re: Vapour Barrier Clothing - 10/23/08 03:14 PM

My experience with using a vapor barrier in a sleeping bag is limited to six below-freezing nights in the Rockies last summer. After the first frosty morning, when my down bag was distinctly damp, I remembered what I'd read about vapor barriers and tried wearing my non-breathable (silnylon) rain jacket and pants to bed over my base layer. It worked just fine. I avoided getting sweaty in the early evening by leaving my sleeping bag open (please remember that this was a Rocky Mountain summer, not a Canadian winter!). Usually after the second time I woke up (one of the problems of aging is that I have to get up several times during the night), I'd zip the bag up. By about 2-3 am, I'd have to snug up the draft collar in my sleeping bag. A couple of nights I was borderline cold about 5-6 am. Those were the nights my dog's water dish froze solid, leaving one puzzled dog in the morning! I didn't sweat and didn't even feel damp. My sleeping bag stayed dry, too. I normally do a lot of sweating, so this was a big surprise to me!