Layering observation

Ian,
I do not know the R numbers (Richard..?), but it seems cotton insulates well depending on how it is woven; those 'pile' sweatshirts are warm, and great for a cold day at the beach; layered cotton clothing is warm when dry, and cotton is what I wear most of the year-round to and from work. As long as I'm not going to be soaked and away from civilization it is a good choice.
And at the other end of the thermometer, in hot dry conditions (Phoenix at 40'C for example), thin cotton clothing is my prefered choice.
When advising my hiking club members on relevant clothingpu

Ian:

Actually, cotton has pretty good insulation value. And the lining/trapped air concept certainly works to enhance insulation.

MontBell's Zeo line of baselayers features a fabric that's made with two different layers of polyester, and a layer of air "trapped" in the middle. GoLite's C-Thru baselayers (superceded earlier this year) feature hollow fibers to trap insulative air.

But when it comes to materials, these companies avoid cotton for winter wear because cotton will lose most of its insulative value if it becomes wet — say from sweat after a hard winter's hike.

An interesting thing about cotton's tendency to absorb water and thus lose its insulating value is that that very absorbtion makes it a superb waterproof material when impregnated with wax or oil. I still think my Barbour Moorland jacket is the best waterproof jacket for strolls in the rain I've ever used; nothing else comes close to feeling so comfortable in the rain. And they are tough and last forever. The only problems are that the wax doesn't do well in extreme cold or high heat, either leeching heat in the cold temperatures or beginning to melt in the high temperatures. Terrible on my backpacks, leaving residue on the back panel and shoulder straps or car seats and such. I've often wondered why no one develops very thin, lightweight rainwear that uses some new kind of rub-in liquid that will waterproof the material, but breathe very well, but not have all the drawbacks of the Barbour Thornproofs.

Not specifically addressing Miguel, but just a general thought…

I always believe in using the right tool for the task at hand. Cotton is great for dry/temperate climes. But stretching its use in cold/humid climes makes me think of other folks who switch wholesale to wool — then wearing it in 100F heat!

Layering Observation

Conventional woven fabrics, like cotton and wool, average 4 clo per inch versus only about 5 clo per inch for the most advanced non woven insulations like Climashield XP and Primaloft One. So for most people an equal thickness of cotton, when dry will feel similarly warm to high tech insulations.

A still air layer adjacent to a fabric layer, up to about ¼” max per fabric layer, will be as warm as an extra ¼ of conventional woven fabrics (1/2" between two layers). A windshirt and a base layer achieve the same benefit as a cotton fabric with an attached liner at less weight and more temperature flexibility.

As others have stated, cotton is fine for urban environments or when you want your sweat to maximize your cooling. The two major downsides 1) are its weight, for example cotton wool used in a thick sweat shirt averages only about .04 clo/oz, and 2) and the more well understood property of loosing all of its insulating value when wet.

About wearing merino wool in heat—I have an opportunity to go on a long hike in high 90 to low 100's temps. in a couple days. I am going to find the upward comfort zone for merino for me. I'm curious—I haven't worn merino wool in temps higher than the low 80's, before. Normally, in such conditions, i would wear a coolmax running singlet or a cotton tee. On second thought, in such hot conditions, I would normally be lying in the shade sipping a cold mojito. Ahh, the things I do in the name of research. :-)>

Again, desert nomads must know something (including those with access to cotton and modern clothing)

I will report back.

(I guess this is a partial thread hijack—sorry—-I'll report back on a new thread)

>(I guess this is a partial thread hijack—sorry—-I'll report back on a new thread)

I don't think so… please cross-post.

Kevin, are you going to be walking in dry or humid heat? Here in Japan very few people wear 100% wool base layers below treeline in the summer because the humidity, with wool's tendency to hold in the heat and water, makes the garments too cloying. Most manufacturers have changed to the no-no linen/ polyester or cotton/polyester blends shirts because the skin can cool off from evaporative cooling. In 100% humidity nothing really ever breathes unless the wind is blowing. Just trying to perspire enough to cool off the skin is a major chore.

I'm off, shortly —-will be about a 7 mi. hike starting and ending in a hot river valley plus 1000' gain to a the top of a promontory and back. There is only intermittent shade provided by scrub oak. It's part of my trailrunning circuit (this time of the year, normally done very early in the AM) and part of my regime in preparing for my late July and Aug. fastpack trips. Elevations will be from 1200 feet to just under 2300. Current temp. is 86 w/ 44% humidity. Expected highs will be about 99 to 101 with humidity dropping to 15 %. I'm wearing an Icebreaker 190 weight Tech T. I will be wearing a daypack w/ hydration bladder.

Miguel–most western N. American conditions are lower humidity along with high summertime temps. at lower elevations. That being said, we can get higher humidity, particularly in the valleys and during afternoon thunderhead buildup.
Thank goodness for the high country. This whole test thing is an abberation from my normal instincts.

In SE Asia I normally have worn loose cotton or cotton-polyester shirts.

See everybody around 5-ish (after post trip libations).

It was indeed pretty hot.

Humidity stayed above 30 % but by Eastern Summer or Asian conditions, it was a fairly dry feeling heat. The following observations are quite subjective and results may vary. You have been warned.

All in all, the merino wool S/S shirt I used ( a Icebreaker Superfine190 weight shirt) stayed quite comfortable through the hike and the hot, sunny, almost shadeless afternoon. It really didn’t perform any less well than the coolmax synthetic shirt I might have worn in similar conditions. The merino wool shirt transported sweat efficiently away from my body and I stayed relatively dry. A capilene or coolmax shirt would have been even more efficient, but the wool did very well, indeed. The shirt had visible moisture in the pits and where my daypack came in contact with the small of my back. I didn’t feel as if I was overheating, I believe the shirt did a stellar job of temp. control through evaporative cooling and through it's inherent insulative abilities—possibly through some homeostatic processes that would need to be scientifically analyzed and described. The shirt, incidentally, is a good UV blocker, there was no tanning or burning. Now here’s the thing, some people don’t like the touch of wool, even a fine soft knit of high quality merino wool. In these hot temperatures, I could feel the wool fiber more ( enough to drive the wool sensitive crazy, I wager) but it never grew to unpleasant proportions for me. In fact, it felt more pleasant against the skin than sweat drenched cotten would. Again, the shirt did end up with pronounced spots of moisture but these dried out within about ½ hour after the end of physical exertion, in the heat—-anything would dry out fast at these temps. but capilene would dry out even faster. Natural fibers absorb a certain degree of moisture, synthetics, not so much or not at all.

Final verdict—merino Wool has a very wide comfort range over a broad band of temps. I’d wear LW merino wool in hot weather in the future. I didn’t feel that I sacrificed comfort by going this route, at all, and as an added bonus, I didn’t reek when I went into a local café for a cooling brew and I got a nice look from the waitress who served me. Go, merino!

Incidentally, my temp. read out was a bit on the high side as the watch was sitting on the ground (in partial shade). Official High at 3pm, according to NOAA was 97˚F.

Kevin, thanks for the report! I was anticipating a good outcome. Your experience was very similar to what I've experienced. In similar conditions I wear Ibex 17.5 micron, 165 weight polos or tees. Even lighter and probably no itch for even for those more sensitive ones. The shirt you wore is the same weight as your Shadow Hoody, which I wear up to the high 70s when I'm expecting cool nights. I did a 50 mile mountain bike ride a couple of weeks ago in similar heat wearing all wool and I was as comfortable as I think can be expected. I think wool stretches out the effect of evaporative cooling, to good effect. Stretching it out too long is not good, but I think having it happen too fast is not good either. I used to use a Bota bag. On a week long trek into Zions in similar heat my water was always cooler the everyone else's. Their water bottles were made of plastic that dried very quickly, kind of like a synthetic shirt. My napped leather Bota bag made the most of the evaporative process. I don't know if wool really makes better use of the evaporative process, it's just a hypothesis. I do think wool's heavily discussed and marketed cold weather benefits have hurt it's perception for warm weather use. I find it not much different than a poly cotton blend given similar fabric weight, color and style. I find my cotton polos are no more cool than my wool ones are and they are almost out of my wardrobe now because they wear out faster.

Kevin, thanks for the detailed report. After looking up 'homeostatic' in the dictionary, I see that is a great word choice for the attributes of wool.

Im going to have to try a 190 superfine or similar in hot weather. My Smartwool crew is too warm for the 3 most hot and humid months here in Japan. I notice immediate relief when switching from wool to polyester in humid conditions.
So far I just can't beat my old REI 1/4 zip polyester shirt for cool sun protection that dries quickly. They dont make 'em with the mandarin collar anymore.
http://www.rei.com/product/705470
Maybe a superfine wool will finally replace it.

BPL had an article comparing wool and synthetic performance last year. Covered many of the topics of the wool discussion. I recall them calling their test shirts the Clown Shirts.

I’ve been wearing light merino wool this summer for all temps. Everthing I’ve done has been low humidity, but it has been performing much as Kevin experienced.

"An interesting thing about cotton's tendency to absorb water and thus lose its insulating value is that that very absorbtion makes it a superb waterproof material when impregnated with wax or oil. I still think my Barbour Moorland jacket is the best waterproof jacket for strolls in the rain I've ever used; nothing else comes close to feeling so comfortable in the rain. And they are tough and last forever. The only problems are that the wax doesn't do well in extreme cold or high heat, either leeching heat in the cold temperatures or beginning to melt in the high temperatures."

Miguel – you are describing the traditional Australian japara, now made with a teflon or other coating:

http://www.wildernesswear.com.au/product.asp?departmentID=36&grouplinkID=87&expandlist=|36||35||2|

This was my first waterproof, and I also have fond memories of the oil in my brother's oiled japara leaking all through his pack when he was living in Darwin. Not sure about your Barbour but my japara wasn't terribly breathable.

The cotton-swelling-when-wet phenomenon is why packs made of canvas (like Macpac) are so waterproof, but the flipside is that they get very heavy as a result of the water they absorb.

When reporting thermal comfort using wool, or any other material, the color of the fabric needs to be indicated to make an informed judgment as to the merits of the material type. Since there about 27 million discernable color shades, a picture would work best. The summer sun generates up to 1,000 watts of energy per m2 and the color, more so than material type, will determine your thermal comfort.

I placed some of my outdoors clothing on the top of my redwood pick-nick table for about 30 minutes. The ambient air temperature was 70 F, the sky was clear, and there was no wind. I then measured the temperature of the fabrics with an infrared thermometer. The following table lists the increase in temperature, because of solar radiation, over the ambient 70F temperature.

1 Dark Orange Patagonia Vest 57.5
2 Black Patagonia Micro-puff Vest 53.9
3 Dark Green Cabela’s Gore-tex Parka 47.1
4 Dark Purple Poly T-shirt 41.9
5 Dark Blue Paddling Jacket 41.2
6 Dark Indigo Poly T-shirt 40.5
7 Burnt Orange Patagonia Capilene 38.8
8 Light Green Patagonia Capilene 38.4
9 Red Montane Wind Shirt 35.5
10 Red RR Zip-T 34.9
11 Mango Kokatat Gore-Tex Paddling Jacket 33.9
12 Yellow NRS Paddling Jacket 32.2
13 Lavender RR Zip-T 31.9
14 Stone RR Zip-T 31.2
15 Light Blue RR Summer Shirt 30
16 Light Beige RR Summer Shirt 28.3
17 White RR Summer Shirt 7.2

Attached are pictures of two shades of white appearing Capilene shirts.

Is my alcohol-ravaged brain playing tricks on me again, or do some Arab Bedouins have wool tents and wear black wool clothing, some Bedouins use white, some thick wool, some thin?

You are having a fevered delerium brought on by severe heat and a lack of a good martini… and you're right, some nomads wore thick clothing and sometimes thin. There is (was) seasonal as well as regional variation in the clothing of desert dwellers. The clothing was sometimes in layers and always somewhat loose and voluminous. Black was a color worn by elders ( who tended to be more sedentary) while both younger men and women (in the case of the Beduoin) often wore bright colors. Some of the tents were black—the old traditional ones woven of goat or camel hair.

My alcoholism is so advanced tahat, I mean that, when I reach the state of having delirium tremens I drink another fifth of Jack and begin havin Kevin Davidsons. What a NIGHTMARE! P.S., in physics, doesn't a "black body" both absorb and radiate radiation at a highly efficient rate, and would that make thick, black wool effecient and getting rid of heat as well as bringing it in? Should the Arabs use white in the day, and black at night?

Robert. Please document your findings here where they will be peer reviewed with gusto, not to mention ribald humor.

And pictures. We want pictures of you wearing black and white beduoin wear—-like Peter O'Toole prancing around in his robes in "Lawrence of Arabia".
:-D

I rode a near century today, starting early but ending (after a prolonged plunge in a lake) in afternoon 90's heat on my roadbike. My bike jersey? Ibex LW merino wool S/S jersey. I'm going to ditch my old stinking synthetic jerseys, for sure. It performed every bit as well as my Pearl Izumis and Castellis and Canaris and still came out smelling like a (OK,OK, metaphorically speaking) rose. There's just no excuse to go back—-with 2 caveats—- I think the superior wicking/ dry-out factor of a high quality synthetic baselayer makes them more appropriate than wool for certain winter conditions where it is imperative to stay dry and keep that body core temp. up. Secondly, wool isn't a terribly strong fiber. This is especially true when wool fibers have reached their saturation point. One does have to be careful—particularly with the lighter weight wools.

That's not Peter O'Toole, that's me visiting a beach just outside of San Francisco. I thought I destroyed all those photos.

You could always use white silk. I have thought of that but don't think it would stay white very long on a long hike.

Re: "Please document your findings here where they will be peer reviewed with gusto, not to mention ribald humor."
Did you mean document Bedouins? Here’s a photo collection, including one man wearing a dark blue robe, and a white turban: http://fohs.bgu.ac.il/bedouin/
Or, did you mean document “black body”? "In physics, a black body is an object that absorbs all electromagnetic radiation that falls onto it. No radiation passes through it and none is reflected. It is this lack of both transmission and reflection to which the name refers. These properties make black bodies ideal sources of thermal radiation. That is, the amount and wavelength (color) of electromagnetic radiation they emit is directly related to their temperature. Black bodies below around 700 K (430 °C) produce very little radiation at visible wavelengths and appear black (hence the name). Black bodies above this temperature however, produce radiation at visible wavelengths starting at red, going through orange, yellow, and white before ending up at blue as the temperature increases. The term "black body" was introduced by Gustav Kirchhoff in 1860. The light emitted by a black body is called black-body radiation (or cavity radiation), and has a special place in the history of quantum mechanics. In radiative heat transfer, heat is transferred between bodies by electromagnetic radiation. In natural radiative heat transfer (that which happens when the electromagnetic radiation is generated naturally by heat), the spectrum of this radiation is that of a black body, and its power depends on the fourth power of the absolute temperature of the body. Planck's law describes the spectral radiance of electromagnetic radiation at all wavelengths from a black body at temperature T. Although Planck's formula predicts that a black body will radiate energy at all frequencies, the formula is only applicable when many photons are being measured. For example, a black body at room temperature (300 Kelvin) with one square meter of surface area will emit a photon in the visible range about once every thousand years or so, meaning that for most practical purposes, a black body at room temperature does not emit in the visible range."

No—I meant personal and practical experimentation, like I did w/ the merino baselayers. :-) Preferably among what's left of the nomadic Beduoin. I'd do it, but my ethnicity is rather persona non grata among them. Also, many of the photos one sees of B. clothing are ceremonial affairs. Not the workaday clothing that sees used under hot desert suns or frigid nights. Also, in many of those pictures on your link, these are settled Beduoin—not nomads, but farmers. Interesting that they are Negev Beduoin—I've seen them on my travels—-very much a people in transition. The nomads are dying out.

Yes, I know all about the physics of black bodies.