Condensation in winter tents?

[Bruce W.1]

Just want to hear your experiences with four-season tents.

I have only one tent that might be considered a winter tent. It is a
single wall Goretex tent with no fly and limited ventilation. It forms
a lot of condensation in low temperatures, which also freezes when below
zero outside.

Since I'm now contemplating a winter trip in the snow, I'm left
wondering about condensation problems in most 4-season tents. Their
designs would lead me to believe that they all have condensation
problems. With limited ventilation, how could they not? Is this true
or am I missing something?

If this is true then I should probably use a bivysack instead of a tent.

So does your 4-season tent have condensation problems in temperatures
near and below freezing?

Thanks for your help.

[Peter]

Post by Bruce W.1
Just want to hear your experiences with four-season tents.
I have only one tent that might be considered a winter tent. It is a
single wall Goretex tent with no fly and limited ventilation. It forms
a lot of condensation in low temperatures, which also freezes when below
zero outside.

I'm not surprised. I've always had lots of condensation problems in
single-wall tents. The outer layer of the tent will lose heat through
radiation to the sky and frequently get below ambient air temperature.
This will cause dew formation (condensation) on both the outside and inside
surfaces (even more inside due to the water content of the air from the
occupants).

Post by Bruce W.1
Since I'm now contemplating a winter trip in the snow, I'm left
wondering about condensation problems in most 4-season tents. Their
designs would lead me to believe that they all have condensation
problems. With limited ventilation, how could they not? Is this true
or am I missing something?

I've had little trouble with condensation in mild winter conditions in
double-wall tents. The inner wall stays warmer since it isn't radiating
directly to the sky so it isn't nearly as prone to condensing the water
vapor. The vapor can therefore pass through the inner wall and condense on
the colder surface on the underside of the fly. This should be designed to
let the water run down inside the fly without falling down on the inner tent.
I use a vapor-barrier liner in my sleeping bag when it's below freezing so
that reduces the amount of water vapor inside the tent (and also makes me
less thirsty in the morning).

[Arild Bergstrøm]

The only thing you can do to minimize condensation is to increece airflow
through your tent.

With a good sleepingbag that should not be any problem.

Arild Bergstrøm
Norway

Post by Bruce W.1
Just want to hear your experiences with four-season tents.
I have only one tent that might be considered a winter tent. It is a
single wall Goretex tent with no fly and limited ventilation. It forms
a lot of condensation in low temperatures, which also freezes when below
zero outside.
Since I'm now contemplating a winter trip in the snow, I'm left
wondering about condensation problems in most 4-season tents. Their
designs would lead me to believe that they all have condensation
problems. With limited ventilation, how could they not? Is this true
or am I missing something?
If this is true then I should probably use a bivysack instead of a tent.
So does your 4-season tent have condensation problems in temperatures
near and below freezing?
Thanks for your help.

[David Snell]

I have had some success limiting condensation (and icing) in my tent by
unzipping a half-moon shaped opening at the top of each door in my tent.
This allows dry, cold air to move through the tent and condensation to
escape. The downside, of course, is that you might have wind, and possibly
snow, blowing through your tent. Keeping the no-see-um netting part of the
door zipped will help some in preventing the latter from happening. The
wind problem can be reduced by orienting your tent in such a way that cross
breezes are minimized.

I've never found that unzipping the door flaps makes the night any colder
because most tents apparently offer ZERO insulation from the outside cold
(theory tested and confirmed by taking a reading with my little zipper
thermometer inside the tent and then outside).

Post by Bruce W.1
Just want to hear your experiences with four-season tents.
I have only one tent that might be considered a winter tent. It is a
single wall Goretex tent with no fly and limited ventilation. It forms
a lot of condensation in low temperatures, which also freezes when below
zero outside.
Since I'm now contemplating a winter trip in the snow, I'm left
wondering about condensation problems in most 4-season tents. Their
designs would lead me to believe that they all have condensation
problems. With limited ventilation, how could they not? Is this true
or am I missing something?
If this is true then I should probably use a bivysack instead of a tent.
So does your 4-season tent have condensation problems in temperatures
near and below freezing?
Thanks for your help.

[Robertwgross]

Bruce, my biggest winter tent is a double-wall North Face. If I take it out in
the cold and then seal it up tight with people inside, I can expect to get
condensation that freezes. That is why I strive to get at least minimal airflow
with vents.

It gets worse when you go up to high elevation. For one thing, the air can't
carry as much moisture, and the people are generally more tired and less
willing to ventilate the tent.

Of course, if a tent won't work for you, there is always an igloo. Cue: Ed.

---Bob Gross---

[Martin Thornquist]

[ Bruce W. ]

Not sure why, but I had the impression that serious winter tents were of
http://www.biblertents.com/2002/itent_eldo.html
Guess I need to do more research.

Single wall tents are very uncommon this side of the Atlantic, and we
do have some serious winter weather. The predominant tent makes here
(Helsport and Hilleberg) are of the type with the poles in the outer
tent (which is usually more than what I consider a rain fly), with the
inner hanging inside. This makes it possible to use a less strong,
possibly more breathable fabric for the inner. My only experience with
other tent designs is a few nights (summer -- although it snowed) in a
Terra Nova Quasar so I cannot compare performance, but I can say that
Helsport inner tents seem to breathe very well, with no condensation
sticking to the inner, only the outer.

In cold conditions (below -10°C or so) I think condensation freezing
on the outer is pretty much unavoidable if there's little wind. When
the temp is near -30 you really don't want to open more vents than
stricktly neccessary, even if that means a little more ice inside the
tent wall.

The only condensation-free tents I've slept in are cotton canvas
military tents with two Optimus 111 on full throttle through the
night, but that is a rather heavy combination, to say the least. I'd
rather deal with some condensation.


Martin

[Ed Huesers]

Post by Robertwgross
Of course, if a tent won't work for you, there is always an igloo. Cue: Ed.

Oh, I doubt Bruce wants to hear it.

Ed Huesers
http://www.grandshelters.com

[Pete Hickey]

Post by Ed Huesers

Post by Robertwgross
Of course, if a tent won't work for you, there is always an igloo. Cue: Ed.

Oh, I doubt Bruce wants to hear it.

Bruce is a lightweight guy. Know how HEAVY an igloo is?
But I hear someone makes a contraption for building an igloo
in place, so you don't have to haul it in with you.

Post by Ed Huesers
http://www.grandshelters.com

[Clyde]

Post by Pete Hickey
But I hear someone makes a contraption for building an igloo
in place, so you don't have to haul it in with you.

Yeah, there's even a book on planning expeditions that endorses it.

[Ed Huesers]

Post by Clyde

Post by Pete Hickey
But I hear someone makes a contraption for building an igloo
in place, so you don't have to haul it in with you.

Yeah, there's even a book on planning expeditions that endorses it.

Had another one taken on Denali but upon leaving base camp they
realized they had to much weight and it took the cut. Cache was not
retrieved when leaving, part of the glacier now.

Ed Huesers
Shameless plug: http://www.grandshelters.com

[Eugene Miya]

Post by Ed Huesers
realized they had to much weight and it took the cut. Cache was not
retrieved when leaving, part of the glacier now.

It became more Kahiltna trash?

[Ed Huesers]

Post by Eugene Miya

Post by Ed Huesers
realized they had to much weight and it took the cut. Cache was not
retrieved when leaving, part of the glacier now.

It became more Kahiltna trash?

Trash!? Them's artifacts... history.

Ed Huesers
Very shameless plug: http://www.grandshelters.com

[Eugene Miya]

Post by Ed Huesers

Post by Eugene Miya

realized they had too much weight and it took the cut. Cache was not
retrieved when leaving, part of the glacier now.

It became more Kahiltna trash?

Trash!? Them's artifacts... history.

How long they been sitting there?
10? 20 years?

Where's Indiana Jones with the RPG?

[Eugene Miya]

Post by Eugene Miya

Post by Ed Huesers

Post by Eugene Miya

Cache was not retrieved when leaving, part of the glacier now.

It became more Kahiltna trash?

Trash!? Them's artifacts... history.

How long they been sitting there?
10? 20 years?

Try two months.

Not artifact yet.

The fella said he was rather embarassed about it. Didn't ask how, he
didn't voluntier. He did say he told the rangers where it was... I think
it would have been a one day round trip to get it from the airstrip.

Fly in an' git it.

Post by Eugene Miya
Where's Indiana Jones with the RPG?

Ford, quiet the brune.

"Deal! with them Hemmingway."
--James Joyce

[b***@telemark.slac.stanford.edu]

-----BEGIN PGP SIGNED MESSAGE-----

Not sure why, but I had the impression that serious winter tents were of
http://www.biblertents.com/2002/itent_eldo.html
Guess I need to do more research.
A double wall tent, with netting under the rainfly, would solve the
problem.
So what's the difference between most 3 and 4 season tents? Structural
strength to handle snow loads?

_ About $100 and one or two pounds. Any reasonably study tent can
be used in the winter provided you check the forecast before you
leave. Winter tents aren't warmer, they're just built sturdier to
stand up to high winds (in theory). One of the great advantages
of winter camping is that you've got much more choice about where
to camp and you've got a pretty good construction material
handy.

_ While if you do a lot of winter camping, you might invest in
a 4 season tent, it's not a requirement to get started. A warm
sleeping bag is, but a 4 season tent is not. Anybody that tells
you otherwise just wants to buy the tent from you cheap after you
realize that winter camping is not for you.

_ Booker C. Bense

[SPeacock]

I have a Stephensons so I was well aware of the hazard ahead of time. As it
turns out it is not as much as others have said and about the same (or less)
for all similar singled walled tents and there is condensation that will
freeze if it is cold enough. Usually no big deal as the condensation is
normally at either end away from (generally) the sleeping area.

Jack Stephensons has a well documented process. You sleep nude, with all
clothes outside, tent fully locked up and airless except for a vent in the
top and an entrance for fresh (dry) air at the bottom opposite end. Some
times that works.

During the winter I have always used a candle near the vent area in hopes
that the extra heat would help the ventilation along.

If your sleeping bag is very efficient, you won't have much of a heat source
to drive the 'chimney' affect. Only the water of respiration which then
sticks to the tent walls (of the single thickness part).

Take along a sponge if its not freezing to wipe up the early morning shower.

If its frozen, take along a windshield scraper...carefull now....

[Pete Hickey]

Plus condensation can be a problem with bivies as well.

Not if you use a VBL in your bag.

[Gary S.]

Most of the condensation in a tent comes from respiration, not
perspiration.
Ventilation can help, but if the ambient humidity is high, all you
will be doing is venting moisture laden air into your tent. Raising
the temperature of the air inside the tent with candle lanterns or
even a catalytic heater will help too.
In many cases all you can do is to try to remove the condensation
from the inside of the tent before it becomes an issue.

Each adult puts out about 1 pint of moisture each night as
respiration, and 1 pint in "insensible" perspiration.

The key in any tent design is to vent that moisture before it
condenses.

In serious winter conditions, the humidity is rarely high, so the
venting will help a great deal.

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

[Sid]

Post by Gary S.
The key in any tent design is to vent that moisture before it
condenses.
In serious winter conditions, the humidity is rarely high, so the
venting will help a great deal.

There was a prior thread on using a candle lantern for moving
moisture/venting in tents where they were satisfied with the results.
Search google groups

Sid

[Clyde]

Post by Gary S.
Each adult puts out about 1 pint of moisture each night as
respiration, and 1 pint in "insensible" perspiration.

BS on the insensible, you've spent too much time looking at the pictures
in the Stephenson catalog. And respiration is a moot point in a bivy
bag.

[MB]

Clyde >

Big difference between a pint and two-thirds of a cup (167 ml) in an 8
hour period. Pumping action from movement gets rid of about half that so
it's about one-third of a cup that gets into insulation; significant but
manageable.

Manageable, yes, but that's assuming rather easy conditions. If
you can't dry the bag, the effect will be cumulative. For
example, the (say) 1.4kg of high-loft down that a good winter
bag has will be in pretty miserable shape after two weeks, when
the 80ml or so a night has added up to over 1kg of ice inside the
bag.

I'd say that a VBL is very good to have in typical mid-winter
backpacking (polar night), unless using huts.

[Clyde]

Post by MB
Manageable, yes, but that's assuming rather easy conditions. If
you can't dry the bag, the effect will be cumulative. For
example, the (say) 1.4kg of high-loft down that a good winter
bag has will be in pretty miserable shape after two weeks, when
the 80ml or so a night has added up to over 1kg of ice inside the
bag.

Arctic conditions are much different from mountaineering. VBL makes more
sense for the former than the latter. On a long climbing trip there are
almost always opportunities to dry gear, not so in the polar winters.

[MB]

Gary S. >

Respiration _should_ be moot in a bivy bag, but many people do pull
their heads inside and exhale there.

But, what should you do if the weather gets bad, if not button
up? (Assuming that you have, eg, a bivybag with a hoop and vent
at lest in the other end).

Get a schnorkel :). Actually, once upon a time I was somewhat
seriously thinking about experimenting with an exhalation
schnorkel for winter camping. Using the exhalation valve of
an old gas mask 'backwards', the exhaled air would go out through
a pipe, whereas the inhaled air would come from inside the
tent.

If not having a schnorkel <g>, a wool balaclava or such helps a
bit in trapping the moisture of the exhaled air, and also warms
and moistens the inhaled air.

In serious winter conditions, the humidity is rarely high, so the
venting will help a great deal.

The absolute humidity is low, but the relative humidity of cold
air is typically high. Venting the exhaled warm and moist air
out of the tent isn't easy, as the moisture will condense
immediately when coming into contact with any cold
surface. A double-walled tent is somewhat better here, as
the inner wall is warmer than in a single walled tent.

Nevertheless, in cold weather, it may be snowing inside the
tent in the morning :). Frostliners have been sometimes
used for trapping the condensed moisture. These were removed,
and beaten outside of the tent in the morning to remove the
ice.

[Andrew Bading]

Post by MB
Gary S. >
Get a schnorkel :). Actually, once upon a time I was somewhat
seriously thinking about experimenting with an exhalation
schnorkel for winter camping. Using the exhalation valve of
an old gas mask 'backwards', the exhaled air would go out through
a pipe, whereas the inhaled air would come from inside the
tent.

I, too, have imagined a snorkel for extreme cold sleeping. My
imagininary version had a long tube that ran the length of the sleeping
bag, warming the air before it is taken into the lungs. The exhalation
side vented outside the tent.
* sleeping with a gas mask would be uncomfortable.
* the exhale side would likely freeze up.
* the whole thing would be excess weight.
These are a few of the reasons I never built my "sleeping snorkel".
Gary, it appears great minds think alike.

[Andrew Bading]

Post by Andrew Bading
I, too, have imagined a snorkel for extreme cold sleeping. My
imagininary version had a long tube that ran the length of the sleeping
bag, warming the air before it is taken into the lungs. The exhalation
side vented outside the tent.
* sleeping with a gas mask would be uncomfortable.
* the exhale side would likely freeze up.
* the whole thing would be excess weight.
These are a few of the reasons I never built my "sleeping snorkel".
Gary, it appears great minds think alike.

Oops, I appear to have wrongly attributed the snorkel idea to Gary.

[Gary S.]

Post by Andrew Bading

Post by Andrew Bading
I, too, have imagined a snorkel for extreme cold sleeping. My
imagininary version had a long tube that ran the length of the sleeping
bag, warming the air before it is taken into the lungs. The exhalation
side vented outside the tent.
* sleeping with a gas mask would be uncomfortable.
* the exhale side would likely freeze up.
* the whole thing would be excess weight.
These are a few of the reasons I never built my "sleeping snorkel".
Gary, it appears great minds think alike.

Oops, I appear to have wrongly attributed the snorkel idea to Gary.

I have a few odd ideas in my time, but I don't need credit for every
one there is.

People have used things like this kniited like a scarf to breathe
through while sleeping, but the frost is a major problem.

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

[Ed Huesers]

Post by Gary S.
People have used things like this kniited like a scarf to breathe
through while sleeping, but the frost is a major problem.

And along came John, long walkin, smooth talkin John:
http://www.polarwrap.com

Ed Huesers
Shameless plug: http://www.grandshelters.com

[Eugene Miya]

People have used things like this knitted like a scarf to breathe
through while sleeping, but the frost is a major problem.

Larry Penberthy who founded MSR made a jacket which had a face mask.
Skiers have face masks for skiing which have nothing to do with knit caps.

[Gary S.]

Post by Eugene Miya

People have used things like this knitted like a scarf to breathe
through while sleeping, but the frost is a major problem.

Larry Penberthy who founded MSR made a jacket which had a face mask.
Skiers have face masks for skiing which have nothing to do with knit caps.

I was thinking of a knitted tube shape, not exactly a face mask. They
didn't work well, so were worth little thought.

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

[Eugene Miya]

Post by Gary S.

Post by Eugene Miya

knitted scarf to breathe

Larry Penberthy who founded MSR made a jacket which had a face mask.
Skiers have face masks for skiing which have nothing to do with knit caps.

I was thinking of a knitted tube shape, not exactly a face mask. They
didn't work well, so were worth little thought.

Nor did what MSR develop.

Statistically, I would not expect climbing nor backpacking for the
greatest examples of innovation (exceptions abound) as the conservatism
and small numbers work against it. Skiing, snowmobiling, or flying are
more likely to see the innovation first as they tend to be less inhibited.
That was the case with googles for instance.

[Gary S.]

Post by Eugene Miya
Statistically, I would not expect climbing nor backpacking for the
greatest examples of innovation (exceptions abound) as the conservatism
and small numbers work against it. Skiing, snowmobiling, or flying are
more likely to see the innovation first as they tend to be less inhibited.
That was the case with googles for instance.

Maybe backpacking, certainly hiking.

Possibly rock climbing, but not ice.

People doing activities like Alpine skiing vastly outnumber
mountaineers and backcountry skiers.

For most companies, it makes sense to go where the market numbers are.
Companies that go for the specialty markets are more likely to be true
believers than MBAs.

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

[Ed Huesers]

Post by Gary S.
For most companies, it makes sense to go where the market numbers are.
Companies that go for the specialty markets are more likely to be true
believers than MBAs.

That's the way I believe even if I am a bit biased.

Ed Huesers
http://www.grandshelters.com

[Eugene Miya]

Post by Gary S.

NIH

Maybe backpacking, certainly hiking.

No question.

Post by Gary S.
Possibly rock climbing, but not ice.

Naw ice climbing is highly limited by ice melting.
There have not be subtantial improvements in quite a while.

Post by Gary S.
People doing activities like Alpine skiing vastly outnumber
mountaineers and backcountry skiers.

That is the main reason (strenth in numbers, economies of scale),
however, they are also less inhibited.

Post by Gary S.
For most companies, it makes sense to go where the market numbers are.
Companies that go for the specialty markets are more likely to be true
believers than MBAs.

Well part of this is the scale up of start ups.
Do you want to make money?
Or you want to make stuff?

[Eugene Miya]

Post by Andrew Bading

Post by MB
Get a schnorkel :).

The old submarine thread.

Post by Andrew Bading
* sleeping with a gas mask would be uncomfortable.

Done it.

Post by Andrew Bading
* the exhale side would likely freeze up.

Not always. Only when the temperature gradient is below freezing
at the point of the mask.

Post by Andrew Bading
* the whole thing would be excess weight.
These are a few of the reasons I never built my "sleeping snorkel".
Gary, it appears great minds think alike.

Great? It would be great if it worked out.
And it has. Aviation and medicine did it.

[Eugene Miya]

The idea of breathing thru a wool wrap or (in my case) a sock, was to
conserve heat. Exhaled air warmed (with some success) the immediate
area around your mouth/nose. After awhile one had to unwrap and try to
dislodge some ice/frost and continue on. It is not an exercise that is
conducive to much sleep.
As I remember there was a similar device for deep cold survival. I
think it was more tubular - but I'd guess it would ice up after a bit
too.

You can use a scarf or sock, but I will repeat that skiers for instance
have more comfortable face masks, lighter, allowances for nose and chin,
etc. There are tubular neck guards, used those as well. In either
case, you will have to occasionally shake off the accumulated frost or
icicles. Been there, done that. The issue/tradeoff is cost.

Sleep is sleep. Like you can get eye shades for summertimer polar sleep,
one learns to live an O2 mask, with muffs/scarfs/masks. This is a
decades old problem.

Saving heat by reusing it as part of a sleep bag system, is still an
open topic. I suspect that a system involving synthetic bags will
happen before down bags.

[Ed Huesers]

Post by Eugene Miya
Saving heat by reusing it as part of a sleep bag system, is still an
open topic. I suspect that a system involving synthetic bags will
happen before down bags.

Well, the Polar Wrap thing might be the closest I've seen. They have
metal that absorbs the heat when you breath out through it. It also
collects moisture because it is cool from the last inhale where the air
was preheated from the previous exhale.
Breathing inside a bag would mean that one could have a thinner bag
which would make it easier for the moisture to pass through the bag.
Dunno.
So, this product wasn't around when you were in Moahai's cold land?

Ed Huesers
Shameless plug: http://www.grandshelters.com

[Ed Huesers]

Post by Ed Huesers

Post by Eugene Miya
Saving heat by reusing it as part of a sleep bag system, is still an
open topic.

Well, the Polar Wrap thing might be the closest I've seen. They have
metal that absorbs the heat when you breath out through it. It also
collects moisture because it is cool from the last inhale where the air
was preheated from the previous exhale.

I would suspect that some sort of heat pipething rather than a metal
thing which usually has a lower specific heat.

This has metal with high thermal conductivity with lots of surface
area to absorb the heat. Once you stop breathing or by the time you are
done exhaling the outer most part of the metal is warmed up above
freezing. Then when inhaling the moisture is brought back into your
lungs. Less dehydration.

You would use something like CaCl2 to remove the moisture on at least
the short term.

Desiccant dryers. They can be dried but yes, on the short term.

But I can foresee problems with that as getting rid of the water
which could not be frozen.

The metal doesn't freeze, heat sink. The remaining moisture would
significantly reduce the dew point.

Light alcohol/antifreeze or glycol might make a prototype heat
exchanger, just not a major market.

Well, we've talked of many uses for Everclear. Bad thermoconductivity
though.

Post by Ed Huesers
Breathing inside a bag would mean that one could have a thinner bag
which would make it easier for the moisture to pass through the bag.

I would not want to compromise for a thinner bag.

You've bivied.

Post by Ed Huesers
So, this product wasn't around when you were in Maohai's cold land?

Neck scarves were. And I went down before Maohai.

Hmmm, how did they dry things out? Ack Maohai. Your land...

Synthetic bags are used in field work for a number of reasons.

If only igloos were easier to build.

Ed Huesers
Shameless plug: http://www.grandshelters.com

[Eugene Miya]

Post by Ed Huesers

Post by Ed Huesers

Post by Eugene Miya
Saving heat by reusing it as part of a sleep bag system, is still an
open topic.

metal that absorbs the heat when you breath out through it. It also

I would suspect that some sort of heat pipething rather than a metal
thing which usually has a lower specific heat.

This has metal with high thermal conductivity with lots of surface
area to absorb the heat. Once you stop breathing or by the time you are
done exhaling the outer most part of the metal is warmed up above
freezing. Then when inhaling the moisture is brought back into your
lungs. Less dehydration.

This isn't a Dune Still suit, you lose the water. Water is energy.
The problem is that you are not merely conducting heat. There is an
issue of transport, and then 2 issues of transfer

Post by Ed Huesers

You would use something like CaCl2 to remove the moisture on at least
the short term.

Desiccant dryers. They can be dried but yes, on the short term.

You understand the idea.

Post by Ed Huesers

But I can foresee problems with that as getting rid of the water
which could not be frozen.

The metal doesn't freeze, heat sink. The remaining moisture would
significantly reduce the dew point.

Metals aren't great heat sinks, They do okay because of conduction.

Post by Ed Huesers

Light alcohol/antifreeze or glycol might make a prototype heat
exchanger, just not a major market.

Well, we've talked of many uses for Everclear. Bad thermoconductivity
though.

I would tend to doubt alcohol, but it would have to be checked.

Post by Ed Huesers

Post by Ed Huesers
Breathing inside a bag would mean that one could have a thinner bag
which would make it easier for the moisture to pass through the bag.

I would not want to compromise for a thinner bag.

You've bivied.

Lots.
In summer you don't need a lot. In many cases you can do it with what
you have in your pockets.

In winter, you have a thinner margin of security.

Post by Ed Huesers

Post by Ed Huesers
So, this product wasn't around when you were in Maohai's cold land?

Neck scarves were. And I went down before Maohai.

Hmmm, how did they dry things out? Ack Maohai. Your land...

The Antarctic interior tends to have low relative humidity.
You will get the odd fog, but very infrequently, so laundry dries.
24 hr. day light helps, but even in polar winter things will dry it only
takes longer.

Post by Ed Huesers

Synthetic bags are used in field work for a number of reasons.

If only igloos were easier to build.

Naw, you can use tents. We used them for months.
Fine snow for igloos, cuts like styrofoam.
They still teach igloo building before sending people into the field.
Maohai was at bases (McMurdo and Pole);
we were in a much smaller field camp.

[Ed Huesers]

Post by Eugene Miya

Post by Ed Huesers

Post by Ed Huesers

Post by Eugene Miya
Saving heat by reusing it as part of a sleep bag system

metal that absorbs the heat when you breath out through it.

I would suspect that some sort of heat pipething rather than a metal
thing which usually has a lower specific heat.

This has metal with high thermal conductivity with lots of surface
area to absorb the heat. Once you stop breathing or by the time you are
done exhaling the outer most part of the metal is warmed up above
freezing. Then when inhaling the moisture is brought back into your
lungs. Less dehydration.

This isn't a Dune Still suit, you lose the water. Water is energy.
The problem is that you are not merely conducting heat. There is an
issue of transport, and then 2 issues of transfer

And I've been trolling for more than two years to find someone that's
tried the Polar Wrap.

Post by Eugene Miya

Post by Ed Huesers

You would use something like CaCl2 to remove the moisture on at least
the short term.

Desiccant dryers. They can be dried but yes, on the short term.

You understand the idea.

Weight and lots of moisture to get rid of, it doesn't dry that well
without lots of air circulation.

Post by Eugene Miya

Post by Ed Huesers

But I can foresee problems with that as getting rid of the water
which could not be frozen.

The metal doesn't freeze, heat sink. The remaining moisture would
significantly reduce the dew point.

Metals aren't great heat sinks, They do okay because of conduction.

The warmth is supposed to be there until the end of the inhaled
breath, if I remember right from talking to the mfg.
In the mold trade, we used to use copper beryllium until they found
out it is a carcinogen. Now they have replacements. But heavier metals
do hold more heat than steels that are normally used in molds.

Post by Eugene Miya

Post by Ed Huesers

Post by Ed Huesers
Breathing inside a bag would mean that one could have a thinner bag
which would make it easier for the moisture to pass through the bag.

I would not want to compromise for a thinner bag.

You've bivied.

Lots.

So, I've heard;^)

Post by Eugene Miya
In summer you don't need a lot. In many cases you can do it with what
you have in your pockets.

They had a nude hiker walk out of southern CO mountains. Came up to
some farmer after a few days of being lost with nothing.

Post by Eugene Miya
In winter, you have a thinner margin of security.

Has never been for the faint of heart.

Post by Eugene Miya

Post by Ed Huesers

Post by Ed Huesers
So, this product wasn't around when you were in Maohai's cold land?

Neck scarves were. And I went down before Maohai.

Hmmm, how did they dry things out? Ack Maohai. Your land...

The Antarctic interior tends to have low relative humidity.
You will get the odd fog, but very infrequently, so laundry dries.
24 hr. day light helps, but even in polar winter things will dry it only
takes longer.

Mallory. This is where pyramids of ice would have come in handy
instead of the regular mummy method of preservation.

Post by Eugene Miya

Post by Ed Huesers

Synthetic bags are used in field work for a number of reasons.

If only igloos were easier to build.

Naw, you can use tents. We used them for months.

Don't look for my sympathy;^)

Post by Eugene Miya
Fine snow for igloos, cuts like styrofoam.

In Mountain Of Ice it looked to be very large ice crystals. You out
on the flats must have had finer grain. Like ND. Drive a car over it.

Post by Eugene Miya
They still teach igloo building before sending people into the field.

Intelligence is ultra-lite.

Post by Eugene Miya
Maohai was at bases (McMurdo and Pole);
we were in a much smaller field camp.

Ah, he was in the tourist camp:^<

Ed Huesers
Shameless plug: http://www.grandshelters.com

[Ed Huesers]

Post by Eugene Miya

Post by Ed Huesers

Post by Ed Huesers

Post by Eugene Miya
Saving heat by reusing it as part of a sleep bag system

metal that absorbs the heat when you breath out through it.

I would suspect that some sort of heat pipething rather than a metal
thing which usually has a lower specific heat.

This has metal with high thermal conductivity with lots of surface
area to absorb the heat. Once you stop breathing or by the time you are
done exhaling the outer most part of the metal is warmed up above
freezing. Then when inhaling the moisture is brought back into your
lungs. Less dehydration.

This isn't a Dune Still suit, you lose the water. Water is energy.
The problem is that you are not merely conducting heat. There is an
issue of transport, and then 2 issues of transfer

And I've been trolling for more than two years to find someone that's
tried the Polar Wrap.

Post by Eugene Miya

Post by Ed Huesers

You would use something like CaCl2 to remove the moisture on at least
the short term.

Desiccant dryers. They can be dried but yes, on the short term.

You understand the idea.

Weight and lots of moisture to get rid of, it doesn't dry that well
without lots of air circulation.

Post by Eugene Miya

Post by Ed Huesers

But I can foresee problems with that as getting rid of the water
which could not be frozen.

The metal doesn't freeze, heat sink. The remaining moisture would
significantly reduce the dew point.

Metals aren't great heat sinks, They do okay because of conduction.

The warmth is supposed to be there until the end of the inhaled
breath, if I remember right from talking to the mfg.
In the mold trade, we used to use copper beryllium until they found
out it is a carcinogen. Now they have replacements. But heavier metals
do hold more heat than steels that are normally used in molds.

Post by Eugene Miya

Post by Ed Huesers

Post by Ed Huesers
Breathing inside a bag would mean that one could have a thinner bag
which would make it easier for the moisture to pass through the bag.

I would not want to compromise for a thinner bag.

You've bivied.

Lots.

So, I've heard;^)

Post by Eugene Miya
In summer you don't need a lot. In many cases you can do it with what
you have in your pockets.

They had a nude hiker walk out of southern CO mountains. Came up to
some farmer after a few days of being lost with nothing.

Post by Eugene Miya
In winter, you have a thinner margin of security.

Has never been for the faint of heart.

Post by Eugene Miya

Post by Ed Huesers

Post by Ed Huesers
So, this product wasn't around when you were in Maohai's cold land?

Neck scarves were. And I went down before Maohai.

Hmmm, how did they dry things out? Ack Maohai. Your land...

The Antarctic interior tends to have low relative humidity.
You will get the odd fog, but very infrequently, so laundry dries.
24 hr. day light helps, but even in polar winter things will dry it only
takes longer.

Mallory. This is where pyramids of ice would have come in handy
instead of the regular mummy method of preservation.

Post by Eugene Miya

Post by Ed Huesers

Synthetic bags are used in field work for a number of reasons.

If only igloos were easier to build.

Naw, you can use tents. We used them for months.

Don't look for my sympathy;^)

Post by Eugene Miya
Fine snow for igloos, cuts like styrofoam.

In Mountain Of Ice it looked to be very large ice crystals. You out
on the flats must have had finer grain. Like ND. Drive a car over it.

Post by Eugene Miya
They still teach igloo building before sending people into the field.

Intelligence is ultra-lite.

Post by Eugene Miya
Maohai was at bases (McMurdo and Pole);
we were in a much smaller field camp.

Ah, he was in the tourist camp:^<

Ed Huesers
Shameless plug: http://www.grandshelters.com

[Eugene Miya]

Post by Ed Huesers

Post by Eugene Miya

Post by Ed Huesers

Post by Ed Huesers

Post by Eugene Miya
Saving heat by reusing it as part of a sleep bag system

And I've been trolling for more than two years to find someone that's
tried the Polar Wrap.

Try one yourself.

Post by Ed Huesers

Post by Eugene Miya

Post by Ed Huesers

CaCl2

Desiccant dryers. They can be dried but yes, on the short term.

Weight and lots of moisture to get rid of, it doesn't dry that well
without lots of air circulation.

It's all about conserving energy.

Post by Ed Huesers

Post by Eugene Miya

Post by Ed Huesers

But I can foresee problems with that as getting rid of the water
which could not be frozen.

The warmth is supposed to be there until the end of the inhaled
breath, if I remember right from talking to the mfg.

The heat is supposed to be there and dumped into the bag, but that leave
liquid water which can turn solid.

That is the problem.

Post by Ed Huesers
In the mold trade, we used to use copper beryllium until they found
out it is a carcinogen. Now they have replacements. But heavier metals
do hold more heat than steels that are normally used in molds.

Have to try other things.

Post by Ed Huesers

Post by Eugene Miya

Post by Ed Huesers
You've bivied.

So, I've heard;^)

No biggie.
So did Rebuffat, Buhl, Terray, and all their colleagues.
Starlight and Storm.

Post by Ed Huesers

Post by Eugene Miya
In summer you don't need a lot. In many cases you can do it with what
you have in your pockets.

They had a nude hiker walk out of southern CO mountains. Came up to
some farmer after a few days of being lost with nothing.

The various tribes were practucally nude even before the white man came
to the continent. Sure, some of them died. But most didn't.
Ever wonder why? This is in part the a.c.a. wild threads.

Post by Ed Huesers

Post by Eugene Miya
In winter, you have a thinner margin of security.

Has never been for the faint of heart.

Winter isn't malicious, but it's not forgiving either.

Post by Ed Huesers

Post by Eugene Miya

Post by Ed Huesers

Post by Ed Huesers
So, this product wasn't around when you were in Maohai's cold land?

Neck scarves were. And I went down before Maohai.

Hmmm, how did they dry things out? Ack Maohai. Your land...

The Antarctic interior tends to have low relative humidity.
You will get the odd fog, but very infrequently, so laundry dries.
24 hr. day light helps, but even in polar winter things will dry it only
takes longer.

Mallory. This is where pyramids of ice would have come in handy
instead of the regular mummy method of preservation.

I'm not clear how Mallory (Everest) works into this. You mean his
mummified body?

Wood like in the historic huts are more fire prone because of the driness.

Post by Ed Huesers

Post by Eugene Miya

Post by Ed Huesers

Synthetic bags are used in field work for a number of reasons.

If only igloos were easier to build.

Naw, you can use tents. We used them for months.

Don't look for my sympathy;^)

Your job.

Tents get up in less than 1/2 hour, have nice wood floors with smart
construction. Flapping doesn't become a big problem.

Post by Ed Huesers

Post by Eugene Miya
Fine snow for igloos, cuts like styrofoam.

In Mountain Of Ice it looked to be very large ice crystals. You out
on the flats must have had finer grain. Like ND. Drive a car over it.

Naw, you could not drive a car. This is why you need tracked vehicles or
huge low pressure big tires. You didn't need snowshoes (that's the joke)
however skis are useful. Cars can drive on thick enough sea ice which
has been steamed down to make it harder, which is also able to support
larger wheeled transports like C-130s, C-141s, C-5s, and C-17s in
early season. This is military information. The Soviets drove over
many lakes in winter to resupply Stalingrad and other battlefields.
Knowing ice thickness, salinity, etc.

Very large crystals only slowly form in areas sheltered from winds
and given a lot of time to form. 6 inch diameter crystals were easily
possible.

Post by Ed Huesers

Post by Eugene Miya
They still teach igloo building before sending people into the field.

Intelligence is ultra-lite.

But it also has to be good most of the time.

Post by Ed Huesers

Post by Eugene Miya
Maohai was at bases (McMurdo and Pole);
we were in a much smaller field camp.

Ah, he was in the tourist camp:^<

Maohai was an astronomer, and his instrumentation had lots of base
requirements. I was with glaciologists, and we have different
instrumentation requirements. This is why Watson is trolling over in the
thread he mentioned Bryson. Maohai had MDs. We were hours by fast
planes from MDs if not days depending on weather. We had unforgiving
arcutate crevasses. He had 1,000 to 100 people to call for help.
We had between 40 to less than 20 people in some cases over the months.
Our worse injury was one person (a friend on our project) who strained
soft tissues, painful, but no fractures, no fatalities.
We had to depend on ourselves first and foremost. All that's left of
there where we were are marker flags which are slowing getting buried as
well as buried 20 ft. high turd towers where our outhouses were.
As they slowly creep their way to the Antarctic Pacific.
And some number of solar power intrumentation platforms which will
ultimately also get buried by drift. I think some of our colleagues
helped drill holes for Maohai's project (PICO). But he can tell you more.

[Ed Huesers]

Post by MB
Gary S.

Respiration _should_ be moot in a bivy bag, but many people do pull
their heads inside and exhale there.

Get a schnorkel :).
The absolute humidity is low, but the relative humidity of cold
air is typically high. Venting the exhaled warm and moist air
out of the tent isn't easy, as the moisture will condense
immediately when coming into contact with any cold
surface. A double-walled tent is somewhat better here, as
the inner wall is warmer than in a single walled tent.

Well, how about it Markus, you seem to be the perfect guy to test
this out for us: http://www.polarwrap.com

Ed Huesers
http://www.grandshelters.com

[Bruce W.1]

Post by MB
But, what should you do if the weather gets bad, if not button
up? (Assuming that you have, eg, a bivybag with a hoop and vent
at lest in the other end).
Get a schnorkel :). Actually, once upon a time I was somewhat
seriously thinking about experimenting with an exhalation
schnorkel for winter camping. Using the exhalation valve of
an old gas mask 'backwards', the exhaled air would go out through
a pipe, whereas the inhaled air would come from inside the
tent.
If not having a schnorkel <g>, a wool balaclava or such helps a
bit in trapping the moisture of the exhaled air, and also warms
and moistens the inhaled air.

Post by Gary S.
In serious winter conditions, the humidity is rarely high, so the
venting will help a great deal.

The absolute humidity is low, but the relative humidity of cold
air is typically high. Venting the exhaled warm and moist air
out of the tent isn't easy, as the moisture will condense
immediately when coming into contact with any cold
surface. A double-walled tent is somewhat better here, as
the inner wall is warmer than in a single walled tent.
Nevertheless, in cold weather, it may be snowing inside the
tent in the morning :). Frostliners have been sometimes
used for trapping the condensed moisture. These were removed,
and beaten outside of the tent in the morning to remove the
ice.

================================================

I once saw a device made for winter joggers. A flat plastic box was
strapped onto your chest. It had a mouthpiece and tube connecting it to
the box. Air was inhaled thru the box to warm it.

What's really needed is a snorkel with a heat exchanger. Air is inhaled
thru and inner tube. Air is exhaled through a surrounding outer tube.

[MB]

Bruce W.1 >

Post by Bruce W.1
I once saw a device made for winter joggers. A flat plastic box was
strapped onto your chest. It had a mouthpiece and tube connecting it to
the box. Air was inhaled thru the box to warm it.

Many years simple and efficient (I'm told) heatexchanger
facemasks were sold over here, intended for skiing, jogging
and other aerobic cold-weather aerobic sports. The problem
was (again, I'm told) that they looked a bit too weird for
continued commercia success. The metal grid brings perhaps to
mind Hannibal the man eater or Darth Wader :). Nevertheless,
a metal grid is simple and efficient, and the breathing
resistance is neglible. One can still see these on some
joggers, and I've hope to eventually find one on a flea market.

That said, I find that a woolen breathe-through balaclava is
pretty good. The problem being that it gets iced up rather
quickly. This isn't all bad inside a tent - the balaclava
acts a bit like a frost liner. And it's also a bit of a
moisture exchanger, increasing the humidity of the inhaled
air , which is good too, as cold air is dry (in absolute
terms) and the moisture loss of exhalation is slightly
reduced.

Post by Bruce W.1
What's really needed is a snorkel with a heat exchanger.
Air is inhaled thru and inner tube. Air is exhaled through
a surrounding outer tube.

I don't see cold air inhalation as a significant problem
when sleeping, as the inhaled volume/time is small as
compared to the one during excercise. Besides, the air
inside the tent is typically already somewhat warmer than
the air on the outside. Adding a heat exchanger would
be nice of course, but I doubt whether it'd be worth much
of increase in complexity, weight and breathing resistance.

[Pete Hickey]

Post by MB
Bruce W.1 >
That said, I find that a woolen breathe-through balaclava is
pretty good. The problem being that it gets iced up rather
quickly.

You don't have a beard, do you? Not only does it ice
up, but it freezes onto your beard. Check out the second
picture here:

http://mudhead.uottawa.ca/~pete/bike.html

Post by MB
I don't see cold air inhalation as a significant problem
when sleeping, as the inhaled volume/time is small as
compared to the one during excercise. Besides, the air
inside the tent is typically already somewhat warmer than
the air on the outside. Adding a heat exchanger would
be nice of course, but I doubt whether it'd be worth much
of increase in complexity, weight and breathing resistance.

Well, it would reduce heat loss, meaning a lighter sleeping bag.
Difference in weight for the bag, would probably be less
than the exchanger, though.

[Jerry M. Wright]

Post by Pete Hickey

Post by MB
Bruce W.1 >
That said, I find that a woolen breathe-through balaclava is
pretty good. The problem being that it gets iced up rather
quickly.

You don't have a beard, do you? Not only does it ice
up, but it freezes onto your beard. Check out the second
http://mudhead.uottawa.ca/~pete/bike.html

In cross-country skiing, I've always found that once my beard ices up,
my face is much warmer. It makes a nice insulator/wind block.

[snip]

Post by Pete Hickey
--

[Ed Huesers]

Post by Jerry M. Wright

Post by Pete Hickey

Post by MB
That said, I find that a woolen breathe-through balaclava is
pretty good. The problem being that it gets iced up rather
quickly.

You don't have a beard, do you? Not only does it ice
up, but it freezes onto your beard. Check out the second
picture here: http://mudhead.uottawa.ca/~pete/bike.html

In cross-country skiing, I've always found that once my beard ices up,
my face is much warmer. It makes a nice insulator/wind block.

That's fine until it gets to weighing a pound or more, course it does
pull the wrinkles out of ones forehead and make one look younger.
Free Igloo Ed wallpaper:
Loading Image...

Ed Huesers
http://www.grandshelters.com

[MB]

Pete Hickey >

You don't have a beard, do you? Not only does it [balaclava]
ice up, but it freezes onto your beard. Check out the second
http://mudhead.uottawa.ca/~pete/bike.html

And you'd need a haircut too... <g>

On the same lines, I've noticed that eyelashes are
prone to icing and sticking the eyelids together when
wearing a balaclava. When wearing goggles, the problem
is replaced with the most inconvenient condensation/
freezing on and inside the goggles. And those wearing
spectacles will often end up seeing much better without
them - regardless of the severity of their myopia -
when having to wear a balaclava or mask to avoid facial
frost bite.

Obviously, the schnorkel would help here too. And,
unlike the tent schnorkel, schnorkels for on the
move are readily available and can be bought at
any diving store :).

[Robertwgross]

...A double wall tent, with netting under the rainfly, would solve the
problem.

A real double wall tent has more than netting under the rainfly. Netting only
under the rainfly would be found in a 1-, 2-, or 3-season tent.

So what's the difference between most 3 and 4 season tents? Structural
strength to handle snow loads?

A real 4-season tent typically handles more snow load and more wind load. It
probably has better waterproofness in the fly. Many will have snow flaps, which
are low along the ground line. They are typically heavier and typically cost
more money.

---Bob Gross---

[s***@gmail.com]

I suggest you invest in a 'serious' 4 season tent which probably has a flysheet which you can put up first single handed in bad weather. There should be sufficient spacing between the inner and outer tent and thus when the inevitable condensation streams down the inside of the outer tent it will just run into the grass, and not into the inner tent. You should never have condensation on the inner tent in a double tent wall system. Alternatively to lessen condensation have a portable solar air-conditioning unit! :-)