Why is my base layer soaked?

[Stephen Seeber]

Companion forum thread to: Why is my base layer soaked?

Sometimes a wet base layer just can’t be avoided. Soaked-based layers happen. Here is why it will happen to you.

[YoPrawn]

Wicking is now sort of passe. All the current hype is around direct airflow through all the mid layers and base layers, and I am starting to believe the hype after trying the new systems this last year.

One interesting this about my MH Airmesh base layer is that when worn right side out, it acts as direct airflow with not needing any wicking action, but when it is turned inside out the airflow aspect is reduced and the wicking aspect is greatly amplified.

I don’t have a real BPL membership, so couldn’t read article, so sorry if my mentions were addressed in the article.

[Scott Emmens]

Hi Stephen, thanks for this. I think you words in the paragraph talking about Figure 3 are incorrect, you say the Black line is Dizier but in the key below the graph the Green line is the Dozier fabric?Also, why did you determine the Dozier to be dry at about 93° in the 3 MPH test but in the still air test determine it to be dry at 102°?

Thanks, Scott

[Stephen Seeber]

HI Scott:  That is an excellent observation!  The green line is Dozier.  The black line is the 204 gsm fabric.  I will ask if that can be corrected.

Your second question: Dry is not determined by absolute temperature.  It is determined by achieving stable temperature. In the case of the 3 MPH test, additional convective cooling occurs which  increases heat loss from the test surface relative to the still air test and this causes a reduction in the surface temperature, relative to the still air test.

[Kevin Babione]

Great article – Thank you.  I’m a habitual base-layer soaker and have two questions for you:

• Who makes shirts in the IVI888 fabric?
• Does treating these fabrics with Pemethrin (i.e. Insect Shield) have any impact on breathability and/or drying time?

[Stephen Seeber]

Hi Kevin.  Thanks for reading!  I do not know what shirts are produced with the IVI888 fabric.  The fabric was selected from a fabric library for its weight.  I also have no idea how Permethrin would impact performance.  Without testing, I could not say how it might impact air permeability or the level of hydrophilicity.

That could be an interesting question.  High air permeability may contribute to improved drying.  Higher air permeability requires larger void space.  Larger void space will reduce fabric SPF rating (sun protection) and insect protection.  So, a Permethrin coating could improve insect protection in a high air permeability fabric.

[obx hiker]

Kevin when it’s warm enough in PA for the mosquitoes to be whining around wouldn’t a shirt that retains moisture like a good old poly or even cotton tee be OK? I like to get wet when it’s hot. Get a little evaporative cooling going on. OTOH I guess I have seen days and hikes with big climbs where it was warm enough to sweat like a pig down lower and get soaked but when you reached enough elevation or slowed or stopped you could get really chilled by all the moisture flashing off.

Speaking of high SPF combined with high air permeability: When I’m out west at some elevation and it’s bright and sunny and warm enough during the day while working hard but cools off fast if you stop or the sun goes lower; I.E. perfect flash cooling situation or it’s shoulder season warm days – cool evenings on the east coast/mountains but still possible bug encounters I’ll wear a really light T like a MH lite T or a brynje and over that a Kuiu Tiburon Toray dot air matrix zip pullover treated with permethrin. I used to wear a Mt. Hardware Canyon Shirt but the Tiburon breaths better and weighs about half ( 5.5 oz. for a long sleeved shirt with zipper!) .  The Tiburon is spf 40 and breathes just about as well as the brynje. OK that’s an exaggeration but it literally does have airholes as part of the weave and the breeze comes right on through. Still enough coverage to keep warm while working down to @ 50. YMMV. I’ve been using mine now for @ 4 years and really like it though will admit that Kuiu stuff can get pricey. It’s tough enough btw and also stretches well due to the dot-matrix weave, and no I don’t get anything for such an endorsement.

BTW stay tuned I’m working up a post about the little red devils; AKA red-bugs – AKA chiggers that hopefully will be entertaining and informative.

Also hat tip to JCH on the insect shield recommendation. Those folks have a smooth operation and it’s great having your own items professionally treated. No more DIY.

[Eugene Hollingsworth]

Hi Stephen – your article confirms why I struggle with my torso being either wet, or dry-ish and chilled when hiking MN during cooler months. Forty years of walking in the woods and I’ve only managed to keep my base layer from being saturated by either slowing down or dressing lightly such that a fresh breeze or dip into a cold spot immediately chills me. The most effective compromise is an arrangement of mid and outer layers that have tons of ventilation and full front zippers for air flow.

Granted, most of my clothing is low-mid priced and I miss out of the latest high tech breathable softshells that might really help, but I doubt that I can keep my back from being saturated with sweat. It’s a real conundrum.

[Jon Fong / Flat Cat Gear]

When you are hot, the body sweats (produces excess moisture) and leaves a thin layer on the skin. The water on the skin evaporates drawing energy away from the body thereby cooling it. So, in this article, you discuss wicking the water into a substrate (material) and converting the moisture to vapor and having the vapor drawn away (calm air and in the wind).

1. The most critical element of a wicking fabric is how well it allows sweat to be drawn away from the skin, converted to moisture vapor, and then transferred out of any clothing layers.

Unless the body cools, won’t it keep producing sweat? That being said, where is the cooling coming from then? It would imply conductive heat transfer through the fibers back to the body and a wicking material?

[Stephen Seeber]

Jon:  Sorry, I am not following what you are asking.  Is you question based on the single sentence you cite or the various concepts discussed in the article?  Please give me a little more to respond to.

[Jon Fong / Flat Cat Gear]

The body is trying to stay cool, what is the mechanism for cooling and how does it relate to wicking and evaporation?  The evaporation of water is a tremendous way to getting rid of energy.  Where is this transition occurring in a layered system?  Does that make sense?

[Kevin Babione]

@OBX Hiker – Ha!  I’m now done hiking in PA until October because of the bugs and heat and humidity.  I’ve got an August trip planned to the Whites, but that’s it during the summer.  I had Insect Shield treat my clothing because of ticks, not mosquitos.  I had 5 nasty tick bites in one day in the middle of April.  The first day started with temps in the upper 30’s and some freezing rain.  The next day was sunny and hit the mid-60’s.  We had just finished a 2-mile uphill and my shirt was soaked.  I took it off and my buddies immediately noticed the ticks – they were big meat-eaters.  So – I’m looking for the most breathable or wicking shirt that can be treated!

[Stephen Seeber]

Jon:

The body is trying to stay cool, what is the mechanism for cooling and how does it relate to wicking and evaporation?  The evaporation of water is a tremendous way to getting rid of energy.  Where is this transition occurring in a layered system?  Does that make sense?

That is not really what the article is about. This article discusses how a base layer fails to a point where the situation you allude to will be likely to occur. I agree with where you are going.  The most effective place for sweat to evaporate is on the skin.  The farther that evaporation occurs from the skin, the less effective evaporation and therefore cooling will be. I have stated this in a number of my prior articles. This article does not discuss the role of wicking layers in heat balance specifically.  However, the concepts discussed here describe why a wicking layer fails to perform.  After all, if the wicking layer is saturated, it is not drying and it is not supporting evaporative cooling.  One of the best ways to waste water, in my opinion, is to wear clothing that do not promote effective evaporate cooling from the skin.  Heat balance is a complicated mix of clothing choices, exertion level and environmental conditions.  This article, among other things, illustrates what can happen with your base layer wicking and drying by varying several of the factors that will ultimately impact heat balance one way or another–too hot or too cold.  Either can result from failed base layer performance.

[Stephen Seeber]

Hi Kevin:  Having spent years mountain biking in PA I can sympathize.  I really hate the stench of deet! I would apply it every day.  It worked generally, but I still came home with ticks periodically.  I recommend you move to Colorado.  Ticks are supposed to be here but I have not seen one yet. I am working towards a summer layering solution but its pretty early in what I am doing.  One of the higher air perm shirts I have tested is Montbell cool.  It is not high enough in my opinion, but far higher than most light fabrics, including perennial favorites like OR Echo, which is considerably lower.  How well will any insect repellent will remain attached to a fiber that is sweated on, rubbed on vegetation and rock,  rained on and washed?  I don’t know, but to start, I would get the highest air permeability shirt you can find and spray it and see what happens.  Can’t be any worse than what you are already doing.  Here is an interesting article.

[Kevin Babione]

@Stephen – Thanks for the article…Instead of buying permethrin this year to treat my clothes, I “sucked it up” and sent them to Insect Shield.  It was surprisingly easy.  I treated my liner socks, outer socks, pants, and shirts.  I don’t bother with other bug repellant – I try hard to avoid hiking when bugs are a problem, but the ticks come out much earlier in the spring than the other biting insects.  It might be a bit neurotic, but my biggest fear with ticks is always them getting into a spot I can’t see or reach.  I don’t worry about them on, for example, my bare arms.

[Matthew / BPL]

@crashedagain

Interesting that you mention Montbell’s Cool line. My kid loves their MB Cool 1/4 Zip in hot desert hiking conditions and I find my MB Cool Hoody to be absolutely miserable in the same conditions. There are a few differences:

1. The kid’s 1/4 is a bright green/yellow whereas my hoody is dark grey.
2. The hoody has a double layer of fabric in the front forming a kangaroo pocket.
3. The kid is skinny and their shirt is worn pretty snug against the skin. I’m chunky and generally prefer a looser fit, so mine is a size larger and pretty loose/baggy.

Would you take a guess about which of those factors is most significant regarding my perception that the Cool line is miserably hot? I hadn’t ever considered #3 but now I’m thinking that might be significant.

[Stephen Seeber]

Hi Matthew:

Congratulations on raising a kid who never complains in the face of adversity.  Perhaps you can share parenting tips with the rest of us.

I find that skin tight in hot weather is a poor choice.  A light weight fabric will simply reach saturation faster because there will be less convective cooling in low wind, high humidity conditions.  In those weather conditions, I find that a loose shirt is more comfortable because air can blow through more freely and circulate between fabric and skin.  So, I would think your loose shirt could be too your advantage.  A dark gray shirt might absorb more solar gain and produce higher shirt surface temperatures than a brightly colored shirt.  I have actually measured this impact at our high elevations here and it is significant.  I try to wear the lightest colored shirts in the summer.  If it is shaded on your summer hikes, you can discount this issue.  The double layer of fabric forming the will locally reduce reduce air permeability and probably add a little thermal resistance, depending on how much air is trapped by the second layer.

There is a  chance, the fabrics are not the same.  You want high air permeability in your summer layer.  It is possible the air permeabilities are different.   Go to the Montbell website and look up each shirt.  For some of these shirts they list the fabric weight.  If yours is heavier, that would likely mean lower air permeability.  I just did that, and the 1/4 zip and hoody versions are both 98 gsm fabric, so, if those are what you have, perhaps not the answer. Another approach would be to tape each shirt on a window with bright light showing through it.  Look carefully at each and try to see which is letting more light through.  This is a rough measurement of porosity.  It is best done with a backlit microscope image and Photoshop to measure the bright spot frequency.  If there is a significant difference in air permeability, you may see it just using the window test.  If all else fails, you could call Montbell and ask if the fabrics are different.  Right now, the Montbell Cool that I have has the highest air permeability of all the light weight base layer shirts I have tested.  It also uses a complex fiber shape that will improve moisture management, along the lines of Cool Max fibers.  It has a higher fiber count than an OR Echo, which means more capillary capacity.  That does not mean that it keeps me comfortable as an only layer in hot conditions–it will get saturated in use despite its superior performance.  It may be better than other fabrics, but no panacea.  Finally, it is possible, perhaps likely, that your metabolism, exertion and fitness levels are different than your son’s. These differences can contribute to your different comfort levels.  If you are really curious if the fabrics are different and cannot get a satisfactory answer, you can send me the shirts and I will measure the porosity and air permeability.  Then we will know for sure.  This is actually I question I have wondered about when I view the wide array of “Cool” shirts they have on the website.

[Matthew / BPL]

Thank you for the detailed answer. 🙂

I have a shirt that works well for me (Patagonia Tropic Comfort Hoody) so it was really just out of curiosity. I like the TC Hoody so much I have three of them.

I saw that Montbell lists the shirts as having the same weight. I’m going to guess it’s the color of the shirt.

My kid is capable of complaining. They are actually a young adult and away at college now but I do think many useful lessons have been learned through hiking and backpacking long distances. Perhaps we can discuss that in another thread at some point.

[Stephen Seeber]

Hi Matthew:

Was in Boulder so I stopped at REI and purchased a Capilene Cool Long Sleeve. It appears that the Tropical comfort is discontinued.  The fabric is the same weight: 3.7 osy or 125 gsm. 25% heavier than Montbell Cool. I would guess the fabric is the same as what you are wearing. I measured the air permeability to be 191 CMF/Ft2., which is less than half the air perm of the Montbell Cool. Also lower than OR Echo. I will be returning this, so I won’t measure its wicking performance.  It should wick fine, but because of the the light weight fabric it will probably saturate pretty fast under high exertion or high heat/high humidity.  My expectation would be that this shirt will be less comfortable than Montbell in summer conditions,  but you have concluded otherwise.  Go figure.  Perhaps you can bring both along on a hike and see how they compare under similar conditions. I wonder if the chemical treatments used by Patagonia vs Montbell have some impact on comfort.  The fabric on the Patagonia feels softer and smoother than the Montbell. Some of that is probably the tighter knit of the Patagonia.  Also, Patagonia uses a miDori bioSoft chemical coating, which is designed to produce a soft, smooth hand, which this shirt has. The Montbell Cool has a rougher surface feel which is, in part due to the knit texture of the shirt.  Of course, my Montbell Cool has been washed many times, so, this comparison may not be comparable with a brand new shirt.  So, do some comparison wearing and see what you can conclude.  Tomorrow, I will return the Patagonia and keep looking for higher air permeability shirts for summer use.

[Brett Peugh]

Great article, thank you.  If you happen to come across any other shirts that are XXL and more breathable than the Echo please let me know as I that is where I am stuck.  Thank you.

[Jerry Adams]

great article again, thanks

I wonder where the water goes when it gets fabric wet?

Does it get absorbed into the fibers?

Or are there little micro water drops wetting the outside of the fibers and between the fibers?

Your surface temperature is like 90F.  That would be a warm condition where evaporative cooling is a good thing.  I’m more worried about cold temperatures.  I guess that’s the surface temperature of the wicking layer which is something like that when it’s cold outside.

When I’m cold, if there’s evaporative cooling from the wicking layer, that will make me cold.  I wonder how much.  How does that compare to wearing more or less insulation.

[Stephen Seeber]

Hi Brett:

Thanks for reading.  I will be looking, so I will let you know.

[Stephen Seeber]

Hi Jerry:

Where does the water go?  When the base layer reaches saturation, it will stop wicking.  At that point, you skin will become increasingly wet.  Some of that water will be forced by diffusion into the saturated fabric.  Since it cannot hold more, the added moisture will tend to drip out and go where gravity dictates.  Depending on the garment fit, some water may simply drip down the skin, again to where ever gravity sends it.

When I’m cold, if there’s evaporative cooling from the wicking layer, that will make me cold.  I wonder how much.  How does that compare to wearing more or less insulation.

If it is cold and you are sweating, you are not in equilibrium with heat loss through your garments to the environment.  This may be because you have too much clothing on or you increased your activity level by, for example, going up hill too fast.  Evaporative cooling is the mechanism that is designed to cool you.  If it works properly, meaning your clothes can transfer vapor to the environment, you won’t trap moisture in your layers and you might be able to achieve thermal balance.  If your clothes do not let vapor escape, then, water will build up in your layers, the thermal insulation value of your layers drops due to trapped water and, when you stop your activity, you may well feel cold.

The fact is, with properly functioning layers that can eliminate vapor, you maintain a broader range of cold weather exertion than if your layers just absorbed moisture without an ability to dry and pass vapor through to the environment.

[Jerry Adams]

and, remove insulation so you don’t overheat and sweat

if you’re sweating, you have too much insulation on

well known knowledge by experts

[Jon Fong / Flat Cat Gear]

When I’m cold, if there’s evaporative cooling from the wicking layer, that will make me cold.  I wonder how much.  How does that compare to wearing more or less insulation.

Well, in cold weather, a very significant amount of moisture control has to do with layer management. Climbing a step grade? Better remove some layers. Stopping for a break? Wait a bit and add layers. IMO , fabrics are great but layer management is fundamental (difficult to do right but imperative).

 

Added this snippet that I found on the interweb.

As more or less all others have written. You dress in layers.

I served as a Swedish ranger, specialized in arctic warfare. My regiment was placed about 90mi above the arctic circle. Annual average temperature is about -1C/30F. Lots of foreign forces went there for specialized training (survival, winter warfare and skills etc.). Anything from pilots to various SF/Ranger units, marines and similar troops.

The biggest issue is to learn- and adapt to the climate. During marches you remove most clothing, basically BDU pants+long johns, shirt with long sleeves and over that a white snow suit. Never get wet, at short breaks dress up briefly.

The worst part is generally static reconnaissance (camouflaged OP), because you have to stay still from anything to hours to days.

Generally we never used tents, we just built temporary shelters. Sometimes we just created the simplest of (emergency) bivouac shelters = dug a hole in the snow down the the ground. Insulated the ground with spruce twigs, added a ground sheet/foam mat and finally a sleeping bag. Slept like that under the clear night sky during -25C/13F alot of times.

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