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Bootstrap
03-22-2009, 12:48
Checking my understanding of condensation.

I assume that:

1. Condensation happens primarily when the air hits the dew-point, and less so due to breathing and sweating by people inside the tent.

2. Tarps, tarpttents, single wall tents, double wall tents all have the same dew- point issue. Condensation will happen, but ventilation dries the surface off, taught fabric at the right angles encourages drainage, and double wall tents have an extra surface between you and the place that condensation occurs.

Did I get that right?

Jonathan

hshires
03-22-2009, 13:25
Yes, that's pretty much it. The thing to understand is that if there's no airflow and there's water in the air then generally the determining factor between limited/no condensation and lots of condensation is fabric temperature. Finding the right microclimate can make all the difference. That means that on cool, clear nights, camping under trees rather than out in the open ensures that your tent stays warmer and less prone to condensation. Same is true for camping up and out of canyons, stream valleys, lake basins, and other places where cool, damp air settles at night. Even a few feet can make a noticeable difference.

-H

mweinstone
03-22-2009, 13:41
heres what were working with. first of all, good question. condensation is a slippery dude. we need to control him . tarp tents have less condensation. the last hour of sleep in the morning is a good time to unzip and air out so as to not only aclimatize your self to the temp outside your cacoon, but also begin the de watering. my doors of my unfloored black diamond megamid open with my lids. and the sudden cold air is my coffie. so much of wilderness comfort is the pre hardening if you will, of our personal comfort abilitys and the resetting of our limits. a hiker named tank, routinely wears clothing undoable for us non hardened. hes a tee shirt till 10!

garlic08
03-22-2009, 13:44
That's the way I understand it, too. For instance, you can make your glasses fog up on a warm day by breathing directly on them. You've just raised the relative humidity above the dew point, even at room temperature.

I saw Henry's point about microclimates illustrated when I camped in a meadow under a tree, next to an identical tarptent out in the open. In the morning after a cool, clear night, my tent (with two occupants) was dry, the other one (with one occupant) was soaking wet.

tmoneygetpaid
03-23-2009, 15:29
Bootstrap! How are you, man?! This is Timber. Shoot me a message and tell me if you're heading back out and how you're doing. Lady Goat and I made it to Springer, and you were frequently in our thoughts those last grueling weeks.

Manwich
03-23-2009, 15:36
http://www.youtube.com/watch?v=8x8t2eZP_zs

Bootstrap
03-23-2009, 15:58
Bootstrap! How are you, man?! This is Timber. Shoot me a message and tell me if you're heading back out and how you're doing. Lady Goat and I made it to Springer, and you were frequently in our thoughts those last grueling weeks.

Hmmm, I suspect there may be more than one Bootstrap!

Jonathan

convertedV
03-23-2009, 16:10
When i read this topic, i think about that sort of things http://sourceradix.com/m/mon.html
You may check that, and most likely it would change your mind. Whatever.

stranger
03-23-2009, 21:56
That definition was pretty technical and I don't know about dew points and what not but basically condensation will occur when there is two different temperatures on either side of a material, so that's why when you take a cold beer out of the fridge on a hot day it instantly gets wet on the outside.

Air flow does help, as it dries the wetness but also removes some of the heat from within the shelter, it's the heat that creates condensation from my understanding.

Tinker
03-24-2009, 00:03
Breath and normal sweating (insensible) while sleeping add to the humidity in the air and bring the dewpoint up, just as humidity due to change in the weather does. Condensation occurs on the underside of a shelter more readily because of the moisture that you add to the air.

Bootstrap
03-24-2009, 00:09
That definition was pretty technical and I don't know about dew points and what not but basically condensation will occur when there is two different temperatures on either side of a material, so that's why when you take a cold beer out of the fridge on a hot day it instantly gets wet on the outside.

Air flow does help, as it dries the wetness but also removes some of the heat from within the shelter, it's the heat that creates condensation from my understanding.

Warm air can hold more water than cold air can. The dew point is the temperature at which air is completely saturated, it can hold no more water, at that point the water turns into rain or condensation.

If you take a cold beer out of the fridge, the warm air is cooled, and loses some of its water. Cooling moist air is like squeezing a damp sponge. This also happens when a cold front comes in and it starts to rain.

See this: http://en.wikipedia.org/wiki/Dew_point

Jonathan