By The Numbers: Testing the Performance of Mountain Hardwear AirMesh Garments

[Stephen Seeber]

Companion forum thread to: By The Numbers: Testing the Performance of Mountain Hardwear AirMesh Garments

Is Mountain Hardwear AirMesh a breakthrough product or a prisoner of wicking base-layer physics?

[YoPrawn]

Those tests are very interesting data. although, I am not sure how they translate to my real-world experience with the shirt. I am not at all close to as smart of some of you here, so feel free to rip my thoughts apart accordingly. LOL

1. Did you ever try running the Airmesh inside out? It completely changes the way it performs in real-world use, when inside out. The mesh layer absorbs liquid much better than the fleece side. It also changes how the air interacts with the heat and moisture exchange.

2. Wicking is lame. Yes, I said that. Wicking is lame. That’s old-school dinosaur stuff. ;) I’ve moved away from any sort of layers that rely on wicking and it has completely improved my clothing system in every way. I now find that having all of my clothing layers with excellent CFM air transport just plain work better in both heat and moisture management. I think wicking is along the lines of older guys using massive boots, where as trail runners are better in so many ways.

3. The trait of how the fleece side does not transfer moisture, but the mesh side does, seems to have been stated in a negative light here. Well, I think it’s actually a massive positive. I use my airmesh shirt as a camp towel, or even at home in the shower. I can turn it inside out and put it on, instantly soaking up water from my skin, then take it off and flip it right side out and now all that moisture is off my skin, but also in a state where it can dry off from the shirt. I can also put the shirt on over my other layers at this point for the same effect.

4. While not part of this test, airmesh is quite a bit more durable than Alpha-direct. My airmesh shirt has over 100 days of not-kind use and shows no signs of wear, even from pack shoulder straps.

5. Airmesh feels and works better next to skin than alpha direct.

6. I think overall it might be difficult to pin-point this new shirt based on traditional notions of versatility and testing protocols. It could be that it is used in ways that do not translate well to some tests, or that some tests might not show the whole picture when it comes to the net versatility of the shirt. The reason I make these questions is because in my real-world testing, I have never once used any sort of shirt that has the same features and traits of the airmesh hooddie I have.

[Marcus]

Great real world testing Stephen and BPL. Thanks for your objective 3rd party reporting.

Stephen, in your subjective opinion, what is your preferred active insulating fabric based on your testing and personal experience?

I admit it has quirks as a garment, but your tests seem to show Alpha direct as a tough material to beat in moisture transfer and weight:warmth.

Have you tested  Kuiu’s Peloton 97 fabric? I’d like to see how that stacks up too

[Stephen Seeber]

Hi Johan:

I  have been following your comments on this fabric, so I am glad you read the article.  I will respond to your comments.

1) I have to destroy the shirts to accomplish the  complete set of tests.  I did not run with the shirt reversed and now, the shirt is in two pieces, so I won’t be able to run in the shirt reversed.  However, the video I made of the shirt wicking in reverse demonstrates that it absorbs moisture much better in reverse.  I did not test drying rate in reverse.  Thinking about this, I can come up with reasons why drying could improve in reverse.  However, I can also come up with reasons why drying would slow. It would be interesting to test this aspect of performance.  So, under some circumstances you might get better performance from the reversed shirt, but under heavy sweating, I doubt it would perform any better.  You obviously have a better feel for this than me.  No matter how you wear this fabric,  poor wetting and little wicking ability on the skin or fleece side and lack of capillary capacity on the normal face side serve to limit moisture management performance of the fabric.

2) I basically agree with you that wicking is not useful or reliable for reasons stated in my prior articles.  I also agree with you that air permeability is critical in removing moisture as long as the layering system provides adequate ventilation to take advantage of elevated fabric air permeability.

3)  I do state the performance of a napped surface as a negative.  It degrades wicking but is often incorporated into a garment designed to wick.  I can see how the use case you describe might work, but I am not sure how practical it would be to wear a garment to absorb moisture from the skin and then flip it to dry.  I don’t doubt this would work.  But it would be a lot of effort and does not address long term use during constant activity.  I would rather wear a system that can continuously support sweat evaporation from the skin and vapor transport out of the layering system.

4) As I said in the article, I expect that this material may provide better durability than Alpha Direct.  If nothing else, it will avoid snagging more easily because of its tighter knit.  However, I wear Alpha Direct as a 2nd layer all winter long for hiking, skiing, biking and more.  I probably have well over 100 days use on my single layer 60 gsm shirt and perhaps 30-40 days on my dual layer 60 gsm shirt.  My garments have suffered no damage and have been washed after every use.    Clearly, as an outer garment, you don’t want your Alpha Direct to be snagged on vegetation.

5)  I have worn Alpha Direct directly on my skin only once, but it was very comfortable.  That is a use case I should explore more, but that will have to wait until fall.   I wore the AirMesh against my skin for hiking, biking and running.  It is also comfortable.

6) Ultimately, any garment involves performance trade-offs.  My lab tests can provide a pretty good understanding of what those are.  In this case, I found excellent warmth to weight performance, excellent air permeability but I found moisture management to be inadequate for intensive activity that involves a lot of sweating.  There are many combinations of activity level, layering approaches and environmental conditions that might support adequate performance of AirMesh.  This is clearly your experience.  There are three more articles left  for this series.  In the last, I will describe my layering approach which serves me well for my activities in the environmental conditions I experience in the Colorado Rockies.  User experience will always vary.

 

[Hanz B]

The octa deployed in the proton Fl seems one sided (compared to above photos)  –  like half the material knitted to a large open mesh such that it’s individual fuzzy fibers sticking away from the skin (easily seen by eye in pockets). Seems like a different weave/deployment.  So curious if that changes the extrinsic properties compared to the weave like deployment above. Obviously your article is amazing and the intrinsic properties are the same. I just wonder if a less dense one sided deployment is why the proton fl shines so less as a versatile lateral – and it definitely does.

[Stephen Seeber]

Hi Hanz:

Thank you for reading.  I pulled out a portion of my now cut up AirMesh shirt and compared it to the photograph from my article on active insulation that shows both sides of the Proton FL insulation.  I would say that these seem to be the same fabric, but in different colors.  It looks like Arcteryx made the same choice as Johan (see above comments from Johan) and uses the fabric in reverse of Mountain Hardwear.  These photographs are produced differently.  The photographs in the active insulation article are taken close up with a cell phone.  The photographs in the present article are produced using a microscope.  This makes them a little difficult to compare.

[Stephen Seeber]

Hi Marcus:

As I discussed in my article on Active Insulation,  the term Active Insulation seems to be a marketing construct that covers whatever performance characteristics a manufacturer is trying to ascribe to a particular product.  Fleece traditionally was a go to active insulation.  I stopped using fleece and replaced it with Alpha Direct.  I have a 120 gsm piece (my first, which I no longer use), a 60 gsm piece and a 2×60 gsm piece.  I use these with layers that provide ventilation so that moisture vapor from the skin can travel through the Alpha Direct and vent to the exterior. Alpha Direct is hydrophobic.  It does not wick.  You really have to work at getting Alpha Direct  wetted from sweating.

I have not tested Kuiu’s Peloton 97 fabric. I get the impression it is popular among some BPL readers.  Looking at Kuiu’s website,  the 97 fabric is said to be a wicking, hydrophobic fabric.  A fabric that is hydrophobic does not wick because water molecules are not drawn to the fibers.  If this insulation is placed against the skin and heavy sweating occurs, moisture will be pushed into and through the garment by diffusion, not wicking.  It is also described as themo-regulating.  This is another strange, overused and generally undefined and misleading term.  Thermo-regulating suggests a performance response that results from a humidity or temperature condition on one side or another of the garment.    Wool may be thermo-regulating to an extent because of the way water is bonded to or released from the hygroscopic interior proteins that comprise the inner cell structure of a wool fiber.  There are other fibers that can change characteristics in response to changes in temperature or humidity.  Neither happens with most polyester fleeces.  So, is this stuff “just fleece” or something different?  If any readers would like me to test one of these garments, drop me a PM to make arrangements.

[Hanz B]

Ahh. I see. Yes. The same likely.

My opinion is that the proton FL continues to have the most use-case scenarios of any jacket I’ve owned (just a great mix of wind protection and breathability at many high output scenarios. I match this with a highly wicking skin tight Patagonia thermal weight base layer and I get a huge spectrum of comfort while moving. (All opinions of course).

And then thinking out loud, the least useful application of an alpha direct product I’ve tried to date was a Kora zenolith sweater matched yak and merino 240g wool with a alpha direct interior and mesh inner. I just never find a situation that this was appropriate for me.

nice article.

[Stephen Seeber]

Hi Hanz:

My next article compares the Patagonia thermal and mid weight base layers.  You may be surprised by my test results, so check it out.

I looked up the Kora Zenolith.  That is one heavy and expensive garment.  The portion of yak fiber is small, so I doubt the user can identify any impact from the blend.   I tried to get a yak garment for an article I am working on.  No luck.  It appears that yak fibers are harvested by yak herders who follow the animals around and pick up the fibers from the ground as they shed.  If true, does not seem like a scalable product.

[Adam Klags]

I’d like to see you guys review the VOORMI river run hoody like this too… my non scientific in field use tells me its the best breathable sun hoody in existence for high temp conditions, would likely hold way less moisture than this garment, looks better, feels better on the skin and its only weakness is how thin it is in mosquito zones. This fabric looks like a bit of a fail to me, many other better options available imho.

[Stephen Seeber]

Adam:  Looks interesting.  Can you look at the label in the garment and post what the fibers are.   This appears to be a bicomponent fabric, but the website is unclear whether the skin side is wool or polyester.

Steve

[Tjaard Breeuwer]

Hi Johan (and others),

I too fail to see how wicking baselayer can be beneficial (if they even exist as advertised). This theoretical concept has led me too experimenting with Alpha Direct as a baselayer, with nothing underneath.

I have now worn Alpha Direct next to skin many times and absolutely love it for this use.

1. It’s very soft against the skin, so pleasant to wear (including sleeping)
2. low moisture gain, and quick drying, mean even if it does get wet(from sweat or outside moisture), it dries so well, that I rarely need to swap it for a dry garment. (for sleeping etc)
3. because of the extremely  high air permeability, and low water absorption, it allows moisture to move rapidly away when I open shell vents
4. because of high R value, and high loft, it provides high insulation performance when covered by a shell.
5. combining 3 and 4 allows me to regulate and adjust for a very wide range of effort and environmental conditions , simply by venting my shell.

 

[Scott S]

Hi. Two comments. 1). The Airmesh has one significant advantage over Alpha: Availability. Other than a few cottage makers (who routinely runout) it is very difficult to find Alpha garments. I love mine—I have both a MacPac hoodie and a Rab Alpha Flash—but I can’t reliably get one. 2) To Adam’s comment about the Voormi, I have the Voormi, and it’s my favorite shirt for walking…in town. On the trail, in anything above 40 or 45 degrees, it’s just too warm for me. It’s moisture management seems okay for a 50% merino shirt, but as Outdoor Gear Labs noted, when it becomes wet it becomes very dark. Not a great feature for a sun hoodie. I am looking forward to trying it in colder temps in the fall.

[Ryan A]

Hi – New Member, love the research. Question for you Stephen. Have you thought about Airmesh under Alpha Direct? Would the AD help continue to move the moisture outward? Or do you think the saturation would stymie the usefulness of the AD?

Thank you!

[Stephen Seeber]

Hi Ryan:

The answer to your question is in Table 1.  In the spin dry test, AD retains far less moisture than Airmesh. 26% water weight for AD and 52% water weight for Airmesh. This is because of its more open knit structure and its use of conventional cylindrical fiber extrusions and, importantly, its hydrophobic fibers.  The saturation drying test further distinguishes moisture handling properties: They both hold about the same amount of water when saturated.  But AD dried in 39 minutes and Airmesh dried in 68 minutes.  This behavior is again the result of the AD open knit structure, its use of conventional cylindrical fiber extrusions and its hydrophobic fibers.   Both metrics highlight very large performance differences between the two fabrics.

I don’t advocate using hydrophilic base layers in contact with skin. If you are sweating heavily (or lightly for light weight wicking fabrics) they will tend to saturate and become an impediment to removing excess heat.  If you want to promote sweat evaporation on the skin or add additional warmth, I suggest wearing a fishnet beneath your AD.  That is what I do all winter.

[Hikari]

Hi Stephen:

I found that you recommend Finetrack Elemental Layer and Brynje as a combo in article “staff pick 2022”,  but do I still need the Finetrack if I have an Alpha Direct ?
1: Brynje +Finetrack+Alpha Direct
2: Brynje+Alpha Direct
Which is better?

Also I recently purchased Patagonia Cap Air and found it to be a good base layer, would you be interested in testing it or comparing it to the Brynje, Finetrack or the combo?

Finally, thank you for writing these test articles, it really helped me a lot

[Stephen Seeber]

When temperatures get cold and I need more insulation, I replace my Finetrack with a 60 gsm Alpha Direct or an Alpha Duo (2x60gsm).  I usually layer the Finetrack over the Brynje in warmer weather, including summer.  I use either long and short sleeve versions of Finetrack or Brynje as conditions dictate.  Depending on conditions and my level of effort, I often wear nothing over the Brynje/Finetrack combination.  (I wish Finetrack came in white or light colors to reduce the solar gain when worn as my outer layer.) The purpose of the Finetrack is to provide some protection against wind while covering my unsightly torso and not wicking liquid moisture.  When it gets hot, I have been known to eliminate the Finetrack and hope the resulting view is not too offensive.  Most of my hiking is in Colorado, so the humidity conditions I experience in the summer will generally be far less severe than in other parts of the country, so your results may vary.  The objective of all this is to encourage sweat to evaporate on my skin and not be absorbed into subsequent layers.  All subsequent layers are selected to provide the easiest path for water vapor to exit my clothing.

[Scott Emmens]

Hi Stephen, I know these are possibly questions for your next instalment but you seem to be answering questions here so I’ll chime in. Can you explain why you aren’t wearing the Finetrack against your skin? It would still serve the purpose of reducing the windchill and keep a modicum of dignity under the Brynje.

The weather is cooling here again slowly so I’m back thinking about all of this again ante a hot and dry summer here in Christchurch. I even geeked out and purchased a couple of data trackers (temperature and humidity) to record conditions and used them last night on a dog walk for the first time. One on a lanyard around my neck on the outside and the other in an internal mesh pocket in my waterproof jacket. I am aware this is probably not particularly accurate, or scientific BUT it gives me some idea of what’s happening.

Thanks, Scott

[Stephen Seeber]

Hi Scott:  You always ask the hard questions.  When I concluded that wicking shirts were not working for me a few years ago, I was sent a Finetrack by a member to examine.  I thought it looked promising and started wearing one instead of a wicking base layer.  Like any hydrophobic fiber, it won’t wick.  However, with enough sweat, the fibers will absorb water through diffusion.    Against my skin, it can work better than a wicking base layer, but not well enough.  The mesh structure of the Brynje gives sweat a better opportunity to evaporate and dissipate as vapor.  It is not perfect.  I can and have worked hard enough to wet the polypro fibers that form the Brynje fibers. Again, through diffusion.  When that happens, I feel cold, like with a wet, wicking layer.  I did that while skinning at 9F last week.  It was colder than usual, and I added more insulation than I should have.  Today, it was 1F, and I wore less insulation than last week, and all worked well.  I do my quantitative testing to inform my clothing choices but then, I try to prove my choices in real life.

By the way, I have also run with sensor tiles.  If more people did this, we could generate lots of performance information on all sorts of gear we use.   At the beginning of winter, I was using them to measure temperature/humidity inside my single-wall tents vs outside conditions to verify a technique for eliminating condensation on the interior tent surfaces.  $100 for two SensorPush HT1 bluetooth sensors that send continuous data to your cell phone.  Amazing.

[Scott Emmens]

Hi Stephen, I’m not sure if that’s a good thing or not, an I apologise if my questions are annoying.

I definitely overwhelm my Finetrack BUT that is running, I’m yet to test it properly whilst hiking/walking, or “tramping” as we call it in New Zealand.

I got two of the Ink-Bird sensors which look remarkably like the SensorPush ones you have. I have downloaded the data, and just learnt how to make a graph/chart in excel to compare the two sets of data (inside/outside). My first experiment yesterday was enlightening as it showed and average of 13.8*C and 92%RH outside, and 22.5*C and 63.8%RH inside my jacket. Absolutely no way that pressure differential is going to work to remove moisture from a WPB.

Any other tips that I should be aware of or looking for with my data collection?

Thanks again for tolerating my annoying questions, Scott

[Bill Budney]

So what could we learn from wearing these sensors? I’m game to try, but not sure that I know what to do with the data.

[Scott Emmens]

Hi Bill, I’m just interested to get some actual data, especially about the RH differential when using a WPB garment. I want to determine my own clothing strategy. Our climatic conditions seem so so different to those that Stephen experiences but until now it’s just been anecdotal. Our RH is so much higher than Colorado.

[Bill Budney]

13.8*C and 92%RH outside, and 22.5*C and 63.8%RH inside my jacket. Absolutely no way that pressure differential is going to work to remove moisture from a WPB.

Are you calculating/estimating vapor pressures on both sides of the fabric? Maybe I’m slow, but it isn’t immediately obvious to me how you use the numbers.

I suspect that climate does play a role in WPB performance. As a sweeping generalization, it appears that people who love their WPBs tend to live in drier climates, while people who think they are pointless (or limited) tend to live in more humid climates. Is that what you are saying?

[Stephen Seeber]

Hi Scott: The pressure difference of your example is 289 pascals or .04 PSI.  Not much pressure, so don’t expect much vapor transmission.  But you have to wonder if that is the right number.  The temperature difference should probably be based on the temperature and humidity at the skin’s surface.  If you had a base layer of some sort on and then placed a sensor in the mesh pocket, as you described, you probably are not seeing the entire picture.

It is unclear whether using the temperature/humidity sensor is superior to simply measuring the sweat accumulated in a wicking base layer as I did for my permeability vs. breathability article.  If you use the humidity sensor, I think you would like to see which garment has the biggest impact on minimizing RH at skin level.

When using the two sensors, you should ensure they both read the same numbers for the same conditions.  Before starting a test, I would place both sensors together in a room.  Let them sit for around 15 minutes to reach equilibrium.  If possible, have a low cost temperature/humidity monitor available.  The temperature on such a device should be pretty reliable.  Humidity will be less reliable as the value in the room goes lower.  Then adjust the offsets so both sensors have the same readings.  The sensors respond to changes in temperature/humidity relatively slowly.  On mine, the sensor is seen through a hole on  the back of the device.

I would wear the sensor on a string fastened around my neck, with the sensor sitting against the skin at the center of the chest, approximately over the heart. It might work best with the sensor hole toward the skin.  The external sensor can be attached to the outside of your clothing so that air can freely circulate around it.  Unclear if the external sensor should be protected from solar gain.

Before starting an activity, I would give the sensor perhaps 15 minutes to reach a “steady state” relative to its environment.  You can tell when this happens if you watch the temperature humidity plot it produces on your phone.  The plot will change rapidly and then flatten. After the plot becomes flat, you can begin your activity.   The outdoor sensor should be put through a similar process.

When you begin your activity, you may want to have a fairly rapid data collection rate: perhaps one reading every 15 or 30 seconds.

I am assuming that you will use the data to compare various garments.  To provide a realistic comparison, you may want to do your activity with a heart rate sensor to get a good idea of your level of effort.    At a minimum, you should obtain your average heart rate during the activity.  When I gathered data for my air permeability vs MVTR article, I had a metabolic test done to convert my heart rate data to Met level data.  Some sports watches provide an estimate of MET level.  This could be good enough as a measure of your activity level.

When you repeat this test for different garments, you will want to conduct the same activity at the same level of effort to make comparisons convenient. You might want to review the methodology I used here.

You will probably have to repeat an activity several times to understand changes that occur with different garments and weather conditions.  You must gain enough data to judge whether this methodology provides useful information.  If you find you can distinguish performance among various garments, you will probably need to develop a repeatable methodology that will yield dependable comparisons among garments.

I experimented with using humidity/temp sensors a bit before doing the data acquisition for my air permeability vs mvtr article. I decided that the sensors I had available were not reliable enough and did not pursue any more testing with these devices until my recent tent project.  The recent project was done with a more highly developed sensor that had better accuracy and better software to compare and work with results.

I think Ryan Jordan did some data acquisition along these lines.  If Ryan reads this thread, perhaps he can provide his opinion on its usefulness.

 

 

[Scott Emmens]

Hi Bill, this is all just a personal interest project, I am not as scientific or skilled as Stephen. I have been keenly reading and asking questions over the last couple of years as Stephen has released his findings. I do work in the Apparel industry here in New Zealand so there is some professional interest here too, but it’s nothing more than me trying to understand how things perform in our climatic conditions. The numbers Stephen has quoted, especially RH% is nothing like what I was seeing on my home, uncalibrated,”toy” weather station!

I have only used my data collectors once so far. One was worn inside my jacket and the other was on a string/lanyard around my neck on the outside of my jacket. It was a cool windy and rainy day.

 

And YES I am saying that climate plays a role in WPB performance. I deal with any complaints about the breathability our or garment that we make and sell and I would say that 95% on complaints are from people who are over dressed and get damp from internal moisture on humid days, in fact almost all of our complaints are from people in the North of New Zealand where it is both warmer and more humid. Gore has a lot to answer for with their “Guaranteed to Keep you Dry” promise!

Hope this helps, S

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