Forum Index » Editor's Roundtable » Field Testing Air Permeable Waterproof-Breathable Fabric Technologies – Part 2: Are There Detectable Differences Under Real World Backpacking Conditions?


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Addie Bedford
(addiebedford) - MLife

Locale: Montana
Field Testing Air Permeable Waterproof-Breathable Fabric Technologies – Part 2: Are There Detectable Differences Under Real World Backpacking Conditions? on 10/25/2011 14:27:18 MDT Print View

Companion forum thread to:

Field Testing Air Permeable Waterproof-Breathable Fabric Technologies - Part 2: Are There Detectable Differences Under Real World Backpacking Conditions?

Edited by addiebedford on 10/25/2011 14:29:13 MDT.

David Chenault
(DaveC) - BPL Staff - F

Locale: Crown of the Continent
testing on 10/25/2011 16:04:15 MDT Print View

That is some seriously dedicated hiking.

I disagree on the Spektr being under sized. The sleeves and torso are actually longer than almost any other comparable jacket (all other things being equal). I'd call the fit actually fitted. They do need to get rid of that goofy lumbar cinch cord.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Field Testing Air Permeable Waterproof-Breathable Fabric Technologies – Part 2: Are There Detectable Differences Under Real World Backpacking Conditions? on 10/25/2011 20:14:52 MDT Print View

Will,

Excellent! Thank you for the hard work and valuable data provided in this article.

I am having difficulty easily discerning which line is for which jacket for similar colors. Please add different line patterns for similar line colors to facilitate interpretation.

Edited by richard295 on 10/25/2011 23:12:19 MDT.

Brendan Swihart
(brendans) - MLife

Locale: Fruita CO
Re: Field Testing Air Permeable Waterproof-Breathable Fabric Technologies – Part 2: Are There Detectable Differences Under Real World Backpacking Conditions? on 10/25/2011 22:38:26 MDT Print View

Excellent report. I generally hate wearing rain shells and only take one when I know I'm going to be hiking in sustained rain in cold weather (usually I'd rather hike in a windshirt with good DWR that absorbs minimal water). For me, this article confirms that fabrics such as event are not worth the extra $ and that the biggest priorities are fit (especially hood) and that the jacket is light and compact enough that it doesn't seem like too much of a burden to carry (9oz max).

Mark Verber
(verber) - MLife

Locale: San Francisco Bay Area
Re: Re: Field Testing Air Permeable Waterproof-Breathable Fabric Technologies – Part 2: Are There Detectable Differences Under Real World Backpacking Conditions? on 10/25/2011 22:51:04 MDT Print View

Thanks will... this is excellent. This is exactly the sort of report I have been hoping BPL would do. Reminds me of the 2001? which looked at moisture accumulation. Just the sort of info glossy from manufactures don't provide, and where the normal person doesn't have access to enough variance to do any comparisons. This is VERY valuable. Thank you.

I also had trouble telling which lines which which. You could do the patterns recommended by Richard... but being a data guy I would say "how's about posting the data via google doc, csv, etc so people can play with the graphs."

I appreciate you indicating that none of the materials are fully up to the task. I read so many people say "X is so breathable" where my experience is nothing is good enough when doing a hard push. I haven't tried all of these jackets/materials, but what I have used match what you describe. I understand why you might have expected PowerShield to function better than your test indicates, but that completely matched my experience using PowerShield in the field. I don't get the membrane soft shells at all. In my experience they aren't as comfortable, breathable, or waterproof as eVENT. The only think that seems to best eVENT are stretch woven which are MUCH less waterproof.

The one material/jacket I would love to see added to this would the the lightest driducks or or rainshield 02 which gives surprisingly good performance, especially in view of cost.

--Mark

eric chan
(bearbreeder) - F - M
OR on 10/25/2011 23:32:46 MDT Print View

one thing that i think would be most interesting to test it the OR torso flow ventilation system ... its basically 2 way zippers down the side of the jackets ...

IME .. it provides extreme ventilation, and if yr wearing synth layers, the occasional rain that comes doesnt matter too much ... also a double zipper allows you to leave the bottom of yr front zip open while having the top closed





edit ... does anyone else think it quite hilarious that a $129 backcountry brand (stoic) jacket outperformed most other yuppie brand jackets that cost double the price ;)

Edited by bearbreeder on 10/25/2011 23:37:16 MDT.

Trevor Wilson
(trevor83) - MLife

Locale: Swiss Alps / Southern Appalachians
Re: Re: Re: Field Testing Air Permeable Waterproof-Breathable Fabric Technologies – Part 2: Are There Detectable Differences Under Real World Backpacking Conditions? on 10/26/2011 01:47:57 MDT Print View

Will, that was awesome. Thank you very much for this very insightful article.

Inaki Diaz de Etura
(inaki) - MLife

Locale: Iberia highlands
Re: Field Testing Air Permeable Waterproof-Breathable Fabric Technologies on 10/26/2011 02:58:51 MDT Print View

Invaluable data. Despite the obvious difficulties to keep the testing conditions coherent, this is more revealing than anything I've seen before in a field where most of the available data is hype.

To further overwhelm Will, I not only second the proposal to include some Propore item but also two rather extreme shell test cases: a woven windshirt (no membrane) and a strictly non-breathable top. Those two benchmarks would adequately frame what WPBs really offer.

Ismail Faruqi
(ismailfaruqi) - F
! on 10/26/2011 06:33:17 MDT Print View

holy friggin cow, this is the most detailed WPB test I've ever seen... Will, thanks for detailed report! Awesome!

edit: I suspect Spektr fares well because it utilizes roll closures instead of zipper. Won't be surprised if it gets Highly Recommended... And agreed with above advices, where is THE driducks test...

Edited by ismailfaruqi on 10/26/2011 06:47:13 MDT.

Roman Vazhnov
(joarr) - MLife

Locale: Russia
Confusing results on 10/26/2011 08:12:24 MDT Print View

Big thanks for the material.
Now some thoughts and questions (in order of appearance in my mind):

+1 for trouble of reading graphs and vote for google docs.
- GoreTex membranes are not air permeable.
- I think the inner liner of Rab and TNF jackets might be a little warmer than the other jackets liners. So it helps to generate more heat inside the jacket and correspondingly more humidity. It can be corrected by the thickness of base layer for example.
- May be the effectiveness of front zip opening was increased because humidity sensor was near the front zip? If it would be near pocket or underarm area, then we might get different results.
-What is the technology behind Stoic Vaporshell and Breeze Dry-Tec?
-I think that control of heart rate during this test series (to make sure it is constant) could help to make conditions more equal.
-And most important thing. It is simple - we need rain gear when it is raining. When it is not raining we can use windshirt and thats all. So for me it would be more interesting to test this rain jackets when there is 100% humidity outside and its rather cold (to make sure we dont overheat to much during testing). Then we can find an answer what type of membrane laminates is more comfortable. And i assume it would be the membrane with high air permeability and that gets more score on the A1 breathability test.

Edited by joarr on 10/27/2011 02:04:31 MDT.

Stuart R
(Scunnered) - F

Locale: Scotland
Re: Field Testing Air Permeable Waterproof-Breathable Fabric Technologies on 10/26/2011 09:29:35 MDT Print View

Very interesting.

One thing not mentioned: with the inside temperature 20-25 degrees F warmer than ambient and the inside relative humidity of 80% or more, it is inevitable that sweat will condense on the inside of the shell (which is cooled by the outside ambient temp). Some mistakenly think this condensation comes from rain leaking in.

Diplomatic Mike
(MikefaeDundee)

Locale: Under a bush in Scotland
"Field Testing Air Permeable Waterproof-Breathable Fabric Technologies – Part 2: Are There Detectable Differences Under Real World Backpacking Conditions?" on 10/26/2011 09:39:28 MDT Print View

Thanks for all the work, but it seems strange not to test rain gear in the rain!
The ventilation issue isn't really relevant imo. If it's raining, all the zips are closed. If it was dry enough to wear a jacket with the front unzipped, i wouldn't be wearing the jacket.

Casey Bowden
(clbowden) - MLife

Locale: Berkeley Hills
Field Testing Air Permeable Waterproof-Breathable Fabric Technologies on 10/26/2011 09:42:58 MDT Print View

Verber wrote: The one material/jacket I would love to see added to this would the the lightest driducks or or rainshield 02 which gives surprisingly good performance, especially in view of cost.

+1

Danny Milks
(dannymilks) - MLife

Locale: Sierras
Excellent Report on 10/26/2011 09:51:11 MDT Print View

Thanks Will for taking one for the team! Subjecting yourself to uphill hikes with not-so-breathable jackets.

One note: the MontBell Thunderhead uses Gore-Tex PacLite Stretch on the arms and elbows (according to their website).

Great report overall. Glad you were able to get so many jackets. I wonder how Gelanots would have compared. It is a four-way stretch WP/B fabric used by OMM, Milo and a few other companies around the world.

Martin RJ Carpenter
(MartinCarpenter) - F
Wind speed on 10/26/2011 09:51:57 MDT Print View

Think there's a good explanation for your confusion.

Notice that he purposefully chose for very still conditions so basically no wind on the undulating walk and 2-10mph for hilly one being notable. Amazed he could get enough days like that actually, but clearly common enough where the testing was conducted!

Now compare the results for Powershield Pro/Neo shell on the two hikes. A very obvious difference, especially for PPro. Or even actually I suspect the Felstrum (negatively), although not sure if thats entirely clear.

On reflection thats very logical, because even PPro doesn't have a *huge* level of air permeability overall. And so other factors are relevant in very still conditions, but once the wind gets up it turns much more important.
(Suspect it actually partially explains the slightly mixed empirical reviews of PPro this.).

So do you often get still, rainy conditions? I'd say not so much in the UK, but it might very well vary :)

Inaki Diaz de Etura
(inaki) - MLife

Locale: Iberia highlands
Unzipped front on 10/26/2011 10:11:15 MDT Print View

> If it was dry enough to wear a jacket with the front unzipped, i wouldn't be wearing the jacket

there actually is a practical application for this in the rain: a WP top plus an umbrella. It's a very versatile combo that I usually use in the long-ish hikes. The combination is also a powerful one: the umbrella allows great ventilation through the head and torso, the latter by partially unzipping the front. You still have a rain top for the arms and for full coverage when the umbrella is not a good idea.

Andrew Skurka
(askurka) - F
Marketing departments gone wild on 10/26/2011 11:14:40 MDT Print View

Will - Pretty awesome testing, nice work. As you pointed out, it's really difficult to test these fabrics under controlled conditions, but even so I think there is a very obvious take-away from this article: the marketing departments at these manufacturers have gone wild in their descriptions of this technology.

A few other points:

1- So WP/B fabrics aren't really that breathable...I think we all knew that. But they are also not very waterproof. Their waterproofness depends on the performance of their DWR, which is easily degraded by dirt, abrasion and body oils. Once the DWR craps out, the exterior layer wets out and the equilibrium process begins working in reverse: it's more humid outside the jacket (because the exterior fabric is saturated with moisture) than inside, so water starts moving inwards. Great, now you're wet from the inside and the outside.

2- The marketing pitch for WP/B fabrics hinges on a consumer's belief that they can actually stay dry when it's wet outside. My experience is that this is flawed expectation. The outdoors has no environmental controls like we are accustomed to in our modern lives: when it's cold, we turn up the heat; when it's hot, we turn on the A/C; when it's raining, we go inside; when it's muddy, we keep to pavement and leave our shoes in the mud room. Backpackers need to get over this idea that you can be immune from your environment -- when it's wet, you should expect to get wet, because you will. It's much more fruitful to focus your attention on how you can minimize the effects of being wet.

Dave U
(FamilyGuy) - F

Locale: Rockies
Re: Marketing departments gone wild on 10/26/2011 11:39:17 MDT Print View

Excellent post Andrew!

I would also add that in my experience, high pressure rain can simply overwhelm the DWR at a point and time even without the 'wearing off' of the DWR over time.

Jim Cowdery
(james.cowdery) - MLife

Locale: Central Florida
vapor barrier on 10/26/2011 11:46:57 MDT Print View

Thanks Will;

As usual you hammer the subject with lots of data.

I agree with Inaki. I think running the same test with a completely non breathable top might show if there is a significant difference between a complete vapor barrier and an expensive breathable jacket. Would the results be significant enough to justify the added cost?

peter vacco
(fluff@inreach.com) - M

Locale: no. california
see, Andrew has it right .. on 10/26/2011 12:21:25 MDT Print View

" Backpackers need to get over this idea that you can be immune from your environment -- when it's wet, you should expect to get wet, because you will. It's much more fruitful to focus your attention on how you can minimize the effects of being wet."

you see, one can even tell the time by looking at the clouds. for instance, if it is raining, it is then time to get wet.
this is why they make wool.
or, if it's Really wet, polarstretch.

one will go a lot farther forward following andrew's advice than endlessly buying new parkas.
--
all that said. Great Test !

and, as a lot of things put on 2 dimensional digital graphs, in an extremely multi dimensional world and analog'ish world, it ain't going to give the whole answer.
case in point, i know for a fact that i can/will/do wear my e-vent parka a vastly lot more than i ever did my goretex ones, and that it runs dryer over a wider range of conditions than the graphs might indicate. and as indicated in andrew's insightful comments, i suspect sometimes the stuff leaks backwards.

once i found e-vent, i consider the fabric issue to be closed as far as me personally. it's good enough that any improvement is not going to increase my range or make a better experience. maybe yours, but not mine.

nice test though ! i like the comparitive condensation meters. if only it was as easy as wearing a different sock on each foot ....

Chris Townsend
(Christownsend) - MLife

Locale: Cairngorms National Park
Field Testing Air Permeable Waterproof-Breathable Fabric Technologies – Part 2: Are There Detectable Differences Under Real World Backpacking Conditions? on 10/26/2011 13:20:17 MDT Print View

Good test Will. I've not tried all these jackets but I have been using the Rab Neo Stretch since last February, when I used it on a wet two week Southern Upland Way hike, and two Active Shell jackets, the Berghaus Velum and Haglofs Endo, over the summer and autumn, which have both been wet here in the Scottish Highlands. I judge waterproof jackets on how comfortable they are when worn all day, as is not uncommon here. On backpacking trips they are often worn all day every day. The wet, windy and humid Scottish weather makes this a tough place for rain gear. The key is keeping comfortable, which means just warm enough and not too damp. Nothing I've used keeps me dry when moving but some fabrics are far better than others (and of course the clothing you wear underneath makes a big difference too - many people wear too much and then sweat, producing much condensation - that's why I said "just warm enough"). Without doing a direct comparative test like Will's I've found the least condensation in Neoshell and Active Shell garments, with eVent not far behind. All three also dry out from inside more quickly than alternatives. I can get quite damp from condensation in any of them when working hard however. But condensation is warm and rain is cold so the first is preferable.

All that said, when it's cold enough (below 40F for me) Paramo performs better than anything else.

Joseph Reeves
(Umnak)

Locale: Southeast Alaska
Re: rain on 10/26/2011 13:28:09 MDT Print View

Interesting and informative test on the one topic that I really struggle with; trying to stay dry in the rain.

Andrew Skurka nails it with his comment about accepting the rain. I've come to learn that if it going to be p*ss rain here, like it is from September to December I either wear non breathable Helly Hansen and sweat, or get by with an OR gore-tex pro jacket with the zipper system that Eric Chan illustrated above.

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: Field Testing Air Permeable Waterproof-Breathable Fabric Technologies – Part 2: Are There Detectable Differences Under Real World Backpacking Conditions? on 10/26/2011 13:31:09 MDT Print View

Another excellent test of equipment with real data to compare. I'm glad to see the issue of how a backpack effects rain gear ventilation covered.

The side vents on the OR gear make a lot of sense. With just the front hem free, it allows air circulation between top and bottom. I rarely trap my rain shell completely under my belt, with the front draped up and over for more air. Hiking in moderate temperatures of mid-50F with light precip and high humidity is my challenge. There's nowhere for the sweat go to!

It would be interesting to see the results compared with a poncho and the same data tracking. DriDucks would have made an interesting product to include too.

Thanks for all the hard work and myth-busting!

Edited by dwambaugh on 10/26/2011 13:54:17 MDT.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Marketing departments gone wild on 10/26/2011 16:04:19 MDT Print View

> 2- The marketing pitch for WP/B fabrics hinges on a consumer's belief that they can
> actually stay dry when it's wet outside. My experience is that this is flawed
> expectation.

Right on Andrew!
This is pure marketing spin of the worst sort, and Gore are particularly at fault here for deliberately trying to deceive the public with their 'guaranteed to keep you dry' claim.

My solution in rain is a silnylon poncho and expect to get wet from condensation underneath. But it's warm-wet, not icy-cold-wet. And my pack is waterproof!

Cheers

Oliver Nissen
(olivernissen) - MLife

Locale: Yorkshire Dales
Very thought inspiring stuff on 10/26/2011 18:02:20 MDT Print View

Thanks for the hard work you've put into this, but I have to second Roman Vazhnov on picking up a number of minor issues that need consideration and add a few other points/corrections. I'll try to make this as brief as possible....

Roman rightly points out the importance of where the humidity sensor is placed in relation to zip openings. I used to own an Arc’teryx Alpha SV jacket, which proved to be useless protection from the cold in anything stronger than a breeze as its storm-flap-less pit-zips offered no resistance to wind penetration (but hey, great ‘breathability!’) On the opposite side of the coin, a big problem with zips is the amount of extra seam-tape they require which locally prevent moisture transfer out of the garment - if the jacket is closer fitting, this effect will be worsened as there isn’t as much air movement inside the jacket.

Roman points to other sets of factors to take into account - aspects of the fabric performance (aside from the membrane) and garment fit make a big difference to breathability and insulation. (Why, you may ask should we separate fabric performance from membrane performance? Well all the branded membranes are offered to brands with a range of different face fabrics, and sometimes different linings too. More on this a little later…) Anyway, here are my points about fabrics:

Firstly, garment fit coupled with fabric stiffness and weight has a noticeable effect. Stiff baggy shells (e.g. shells with laminated fleece linings) hold much of their surface away from the wearer, and with static folds of excess fabric, trap spaces of still air inside the garment - effective insulation. (This is partly why stiff heavy shells are popular in the sailing fraternity.) Of course more insulation = more heat stress = more sweating = humidity. It’d be very difficult to measure this effect, but it’d be interesting to hear if Will thinks this might have been a factor with any of the test pieces.

Still relating to fit, the second factor is garment coverage – how low is the hem and high is the collar? More coverage = more insulation and more area where sweating’s evapourative-heat-loss is hindered = more heat stress = etc. (you know the equation!)

Thirdly, the insulating effects of a shell may go further. If a shell is closer to equalising its temperature with outside cold it will promote more condensation on its lining which will reduce our humidity measurements (though not necessarily improve comfort over the long-run – which depends on what then happens to the condensation – my next point.) It’d be interesting to see the R-values (insulation) of the different text piece fabrics. (I really don’t know how much variation there would be and nor do I know how far this might affect condensation – can anyone enlighten me?)

Fourthly, if higher air-permeability allows wind to rapidly cool the jacket’s internal microclimate, then condensation and attendant higher conductivity and evaporation chill will occur deeper inside a layering system (if midlayers are worn - not in this test) as the dew point moves inwards. (Note that venting after building up a sweat will also have the same effect – so it’s best venting before you get all hot and sweaty in the first place!) This is only mitigated by the fact that as the jacket is so breathable, less humidity will have built up inside it in the first place. Of course this point is part of the common objection to air-permeable waterproofing – it’s not entirely windproof.

My fifth point is how shell linings aid comfort in a way not measured by this test – a good lining will absorb condensation or otherwise make it more acceptable (why 2.5L isn’t as comfortable as 3L). Maybe Chris Townsend’s experience with Neo and Active shells having less condensation than eVent is that they are faster at absorbing and spreading out condensation than the rather run-of-the-mill light grey tricot that lines eVent fabrics?

This brings me on to the sixth and final point. Point #4 in the article doesn't emphasise that any particular membrane will be laminated and sold with a wide range of different face fabrics all with their own varying levels of performance - it's not that one fabric is always mated to another membrane. I’ve seen suppliers’ own lab-test results and the same membrane will have vastly different MVT scores when laminated to different faces (sadly I’m not at liberty to quote figures). To sum it up, there is little consistency for the consumer to rely on and no marketing that one can take at face value - what's new?!

An aside… midlayers and insulated shell technologies can hinder moisture transfer in your layering system far more than the shells that might be worn on top of them. My Mtn Hardwear ‘monkeyman’ jacket is a bad offender. With ‘high-loft’ surfaces on inside and out, it is densest in the middle so capillary action doesn’t work in its favour. It seems to be particularly good at just holding moisture and getting claggy (unless I wear it exposed directly to the wind, in which event I may as well not wear it at all). Other bad offenders are synthetic fibre insulated garments (Primaloft etc) - two windproof layers with a thick still layer entrapped in a hydrophobic mat - all is not good on the moisture transfer front. Warm though! (I’d be curious to see how quilting shell and/or lining to Primaloft might vary breathability - a wind-flapped shell layer could help convect moist air through the otherwise inert fibre mat.)

Finally those (slighly anal) corrections I promised:
As Roman pointed out, GoreTex membranes generally aren’t air permeable (Their tent membranes are and perhaps Active Shell is too?!)

“A plain woven fabric without any membrane or coatings can be very breathable... but not water-resistant” - I dispute that. A dense weave/non-woven fibre mat + DWR, or Ventile can be highly water resistant.

“A polyurethane membrane requires two phase changes (vapor to liquid to vapor) to vent moisture” - true for hydrophilic PU membranes (and also that famous polyester-polyether block copolymer membrane- Sympatex), but there are also hydrophobic microporous PU membranes too. These act much like ePTFE. I suspect Neoshell is one of these and as I’ve hinted above, Gore’s Active shell maybe a combination of ePTFE + microporous PU, as opposed to their usual ePTFE + hydrophobic PU lamination, but I might be wrong?

There... I'm done! :)

Edited by olivernissen on 10/27/2011 15:57:29 MDT.

George Matthews
(gmatthews) - MLife
Re: Field Testing Air Permeable Waterproof-Breathable Fabric Technologies – Part 2: Are There Detectable Differences Under Real World Backpacking Conditions? on 10/26/2011 18:09:10 MDT Print View

Great article and great comments. Both make BPL worth the dimes.

eric chan
(bearbreeder) - F - M
Re: Re: Field Testing Air Permeable Waterproof-Breathable Fabric Technologies – Part 2: Are There Detectable Differences Under Real World Backpacking Conditions? on 10/26/2011 19:53:50 MDT Print View

The side vents on the OR gear make a lot of sense. With just the front hem free, it allows air circulation between top and bottom. I rarely trap my rain shell completely under my belt, with the front draped up and over for more air. Hiking in moderate temperatures of mid-50F with light precip and high humidity is my challenge. There's nowhere for the sweat go to!

dale ... for those conditions i heartily recommend OR's torso flo system

as long as you are wearing quick drying synth base layers, and not over dressing ... even the rain which gets through the open zips will dry fairly quickly with yr body heat pushing out the moisture ... or at least get less damp

the key with the OR system is that you can fully ventilate the sides so that it acts as somthing like a running jersey, or a poncho ... you can also open up the front different ways as it has a double zip ...

its also quite useful for high exertion as you can open it all up when moving, and then close it all up at stops ...

as with anything else you WILL get wet if it rains enough, but IMO ORs system allows enough ventilation and temperature control that you have many options ... and im a very sweaty pig ...

Warren Greer
(WarrenGreer) - F

Locale: SoCal
Extensive Effort on 10/26/2011 20:12:42 MDT Print View

Will, thanks for that. Now let the manufacturers come and analyze that. They probably know this stuff already, but now its more in the public domain. And it sure fly's in the face of all their outrageous claims.

Further, it just shows that this technology is in it's infancy and there's a very long way to go. Hopefully there'll be some significant break throughs in the next few years because of the attention that Will and BPL bring with these reports.

I would also like to know how DriDucks fits in here. It sure breaths much better than my Marmot Aegis.

Finally, rain jackets aren't just for rain. Many of us live in drier climates where we don't see much rain. We carry them just in case. But we also carry them to trap heat in the morning/evenings or to provide additional warmth in our sleep systems. Having a fabric that breaths well in those situations is also very attractive.

Samuel C. Farrington
(scfhome) - M

Locale: Chocorua NH, USA
Part 2 on 10/26/2011 20:21:11 MDT Print View

Thank you so much, Will, for this article. It is going to save me umpteens of $, and a lot of disappointment!

Just a couple points:

" ...fabrics such as event are not worth the extra $ ..." (posted above).
How funny that I reached just the opposite conclusion about eVent from your article.
Just goes to show we all look at things from different perspectives.

I am partially color blind, so much appreciated the notes that reviewed and explained the graphs. Made it all work for me.

The post about the absence of rain raises a good point. The quality of the outside DWR treatment probably plays a big role, and may explain why I'm wedded to my Patagonia Specter after years of hiking in the rain with wetter and heavier GTX.

So, in part 3 do you run on treadmill under an industrial strength shower nozzle? (Sorry, couldn't resist.)

Edited by scfhome on 10/26/2011 20:23:06 MDT.

Tom Kirchner
(ouzel) - MLife

Locale: Pacific Northwest/Sierra
Re: Re: Re: Field Testing Air Permeable Waterproof-Breathable Fabric Technologies – Part 2: Are There Detectable Differences Under Real World Backpacking Conditions? on 10/26/2011 20:24:42 MDT Print View

"The one material/jacket I would love to see added to this would the the lightest driducks or or rainshield 02 which gives surprisingly good performance, especially in view of cost."

+1 Particularly for trail hiking.

Tom Kirchner
(ouzel) - MLife

Locale: Pacific Northwest/Sierra
Re: Marketing departments gone wild on 10/26/2011 20:32:39 MDT Print View

" Backpackers need to get over this idea that you can be immune from your environment -- when it's wet, you should expect to get wet, because you will. It's much more fruitful to focus your attention on how you can minimize the effects of being wet."

A huge +1, as in staying warm.

Mark Handy
(mhandy) - M
quantitative versus subjective on 10/26/2011 20:57:27 MDT Print View

So do these numbers square with BPL's consistent opinion that eVent keeps one significantly drier? In particular, Will, did the humidity numbers square with your subjective experience of the jackets?

I am inclined to doubt the humidity numbers and trust the subjective opinions. Commenters have already mentioned the issue of the location of the hygrometer. Another hypothesis: There is some kind of steady-state effect that keeps the humidity inside the jacket pretty constant, despite real differences in how much moisture various jackets let out. In that case, the effect of increased expulsion of moisture might be found in the shirt, not in the air inside the jacket. Did your shirt feel less soggy in some jackets than in others?

If this idea seems right, here are two tests that might put numbers on the subjective impression that eVent is better than old-fashioned Gore-Tex: (1) wear the hygrometer inside your shirt, instead of inside the jacket, and see if there is a bigger humidity difference nearer your skin (which is what you care about, after all); (2) wear a water-absorbing shirt, like a heavy cotton T-shirt, and see if there is a significant difference in how wet it is, say, ten minutes after the end of the sustained uphill walk.

Mark

David Chenault
(DaveC) - BPL Staff - F

Locale: Crown of the Continent
WPB v. coated on 10/26/2011 22:13:19 MDT Print View

This spring I tested a coated shell (a packa) back to back to back against a PU and G-tex shell. This gave me a whole new appreciation of what breathability means, as the difference between the packa and the others was quite drastic over several hours of sustained hiking in the rain.

I'll gladly deal with current WPB tech. Now if we can just get manufacturers to take hood design more seriously.

Eric Blumensaadt
(Danepacker) - MLife

Locale: Mojave Desert
Undulating Hikes on 10/26/2011 23:25:50 MDT Print View

Thanks Will, for a very good review and clear, graphic charts.

Now I see why my REI Kimtah eVent parka has worked so well both as a wind jacket and as a rain parka.

MOST hikes are undulating and according to your charts and my own experience eVent seems to work in that situation of heating up and cooling down repeatedly.


P.S. (WPB STANDARDS) Is there SOME way we consumers in the hiking/backpacking community could pressure the WPB garment industry to publish "waterproof" and "breathability" figures based on INDUSTRY STANDARDS? Eddie Bauer does it with their B 200 WPB parka, why not everyone else?

Edited by Danepacker on 11/02/2011 12:02:22 MDT.

Mark Verber
(verber) - MLife

Locale: San Francisco Bay Area
Re: quantitative versus subjective on 10/27/2011 00:49:55 MDT Print View

Mark suggested:

> wear a water-absorbing shirt, like a heavy cotton T-shirt, and see if there is a significant difference
> in how wet it is, say, ten minutes after the end of the sustained uphill walk.

This was something that Alan Dixon did in 2001 and wrote up in the BPL article High Exertion Moisture Accumulation in Rain and Wind Shells

Richard Gless
(rgless) - MLife

Locale: San Francisco Bay Area
Field Testing Air Permeable Waterproof-Breathable Fabric Technologies – Part 2: Are There Detectable Differences Under Real World Backpacking Conditions? on 10/27/2011 01:02:16 MDT Print View

>"The one material/jacket I would love to see added to this would the the lightest driducks or or rainshield 02 which gives surprisingly good performance, especially in view of cost."

I agree. I would really like to see how this material does in comparison with the more expensive materials. In my limited experience it appears to do well.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
DWR coating on 10/27/2011 08:20:36 MDT Print View

If the DWR coating wets out, then the WPB membrane quits working.

In that case, why even bother with the WPB membrane? Just get a good DWR.

Everyone talks about the technology behind WPB membranes. Maybe what's important is the DWR coating? What is the technology behind that?

I have noticed that with a DWR coating, if there is something that absorbs water touching the inside of the fabric, water will be wicked through the fabric into the absorbtive material. Maybe you need a DWR coating, and then a hydrophobic material inside?

Marco A. Sánchez
(marcoasn) - M

Locale: The fabulous Pyrenees
Re: Marketing departments gone wild on 10/27/2011 08:29:28 MDT Print View

A must-read about what to expect from rainwear:

FAQ - Rainwear - parkas and trousers, etc

Cheers

Steven Schaftlein
(sschaftlei) - MLife

Locale: Mid West
Re: Field Testing Air Permeable Waterproof-Breathable Fabric Technologies – Part 2: Are There Detectable Differences Under Real World Backpacking Conditions? on 10/27/2011 08:30:05 MDT Print View

Another well done article based on good science and practical experience. "Miracle Fibers" are only one part of maintaining comfort. Along with the proper choosing of insulating layers, toboggan hat, and neckie, the unzipping of the front of the jacket is a key method of controlling comfort, temperature, etc. A willingness to adjust all of the above helps a lot. (In colder weather I will add a layer when descending a long distance and remove a layer when ascending a long distance.)

Goretex was a great step forward when it first came out. It provided another option for individuals to choose. These new fibers with their ability to breath before temperature and humidity reach the level of "vapor" are definitely an improvement.
They provide additional options. Each person needs to discover and utilize what he or she finds most comfortable and affordable.

Wool, leather, canvas, and cotton were once the standard for outdoor clothing. Then nylon and other synthetic materials came along. Similar advances continue to be made in all aspects of outdoor equipment. Our menu is no longer limited to a few choices. We have an ever growing buffet of possibilities. We should not be afraid to taste the new recipes.

Chris Townsend
(Christownsend) - MLife

Locale: Cairngorms National Park
DWR treatment on 10/27/2011 09:40:21 MDT Print View

"If the DWR coating wets out, then the WPB membrane quits working.

In that case, why even bother with the WPB membrane? Just get a good DWR."

Not quite correct. When the DWR treatment wets out the WPB membrane doesn't breathe as well so condensation build-up inside is greater. But the WPB membrane remains waterproof. In most garments with just a good DWR you will get wet in heavy or prolonged rain (except with Paramo or similar two-layer garments. In dry areas with only occasional rain just a DWR treated garment may be fine, and will be more breathable than any waterproof, but in wetter places a fully waterproof is needed if you are going to be out in the rain for long.

Diplomatic Mike
(MikefaeDundee)

Locale: Under a bush in Scotland
Not just for rain? on 10/27/2011 10:00:16 MDT Print View

"Finally, rain jackets aren't just for rain. Many of us live in drier climates where we don't see much rain. We carry them just in case. But we also carry them to trap heat in the morning/evenings or to provide additional warmth in our sleep systems. Having a fabric that breaths well in those situations is also very attractive."



A windshirt would be just as good, if not better, in those circumstances.

Greg Letts
(gletts) - F - M

Locale: Northern California
detectable differences on 10/27/2011 10:15:37 MDT Print View

Thanks for the detailed report. It verifies a similar conclusion I had come to after years of wearing Paclite and switching to an eVent jacket last year. I could definitely feel almost a cooling effect inside the eVent piece.

The point about darker colors changing performance deserves more attention at retail.

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: Not just for rain? on 10/27/2011 10:28:13 MDT Print View

'Finally, rain jackets aren't just for rain. Many of us live in drier climates where we don't see much rain. We carry them just in case. But we also carry them to trap heat in the morning/evenings or to provide additional warmth in our sleep systems. Having a fabric that breaths well in those situations is also very attractive.'

"A windshirt would be just as good, if not better, in those circumstances."

I've sat on that teeter-totter so many times with clothing selection (or gear selection in general). If I were going to take the absolute minimum number of garments, a rain shell trumps a windshirt for handling harsher conditions. It is an easier choice if the forecast is for rain-- the windshirt can stay home. The real quandary is whether you should march off into the backcountry with no rain shell if the weather is good. IMHO, that is where a DriDucks jacket comes into play.

Of course what everyone wants is a 4oz rain shell that breathes like a windshirt. {up music, Jimmy Cricket singing "Wish Upon a Star."}

Diplomatic Mike
(MikefaeDundee)

Locale: Under a bush in Scotland
Choices, choices. on 10/27/2011 10:53:15 MDT Print View

I was simply replying to Warrens post, Dale.
Due to the unpredictability of the Scottish weather, i always carry a rain shell. I always carry a wind shell too. As Chris posted earlier, being damp in Scotland is usually a fact of life. Staying comfortably damp is the ideal.
I try to wear my rain shell as little as possible, and the windshell is worn on nearly every trek i'm on.
The only time i leave the windshell at home, is if i'm wearing Paramo in winter. My Aspira smock goes on at the start of the day, and stays on.

eric chan
(bearbreeder) - F - M
bear on 10/27/2011 10:59:41 MDT Print View

im sure not too many people here are fans of mister gryllls

there was however this one episode where they simulated hard windblown rain and bear did his best to survive it overnight under a tree branch shelter ... they used a heat camera to record his temps ... he was wearing no rain gear, just DWR and standard outdoor clothes

he basically went hypothermic in short order

now you may think hes a showman or "fake" ... but theres no denying that he is a very fit and mentally strong person, more so than the majority on this site

if theres only one shell later i NEED to bring ... its a waterproof

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: bear on 10/27/2011 11:14:04 MDT Print View

"im sure not too many people here are fans of mister gryllls"

Jeez, Eric, that is like going to the Cable Guy for computer support ;) I value your experience and opinion far more than the PT Barnum of Survival!

If you want to get wet and cold, the west coast of Canada is a good place to start, seconded by my climate 100 miles south. Rain gear is mandatory. I have allowed myself to take a DriDucks UL poncho when going on day hikes on August; the rest of the time, I'm ready for a deluge-- or 24 hours of drizzle and wet brush.

Buck Nelson
(Colter) - MLife

Locale: Alaska
So many variables in choosing rain gear. on 10/27/2011 11:21:22 MDT Print View

Thanks for all the hard work on the testing.

Finally, rain jackets aren't just for rain.
Absolutely. Usually when I'm wearing rain gear it's NOT raining hard. I too am usually wearing it for a wind shell, for warmth, or even while doing laundry on a long hike. A good breathable will do these jobs as well as serving as rain gear.

...it is inevitable that sweat will condense on the inside of the shell (which is cooled by the outside ambient temp). Some mistakenly think this condensation comes from rain leaking in." I agree.

I also agree that it's important to accept certain discomforts that are unavoidable, like a certain amount of wetness when it's really rainy, but the gear we use and how we use it can make a big difference.

When the DWR treatment wets out the WPB membrane doesn't breathe as well so condensation build-up inside is greater. But the WPB membrane remains waterproof."

I agree.

Mark referenced this article: High Exertion Moisture Accumulation in Rain and Wind Shells

In that test the breathable shell resulted in 6 oz. of sweat in the base layer, and non-breathable, 10 oz. I consider that to be significant difference in comfort. Since this forum is all about lightweight backpacking, carrying an extra 4 oz. of sweat, and presumably 4 more oz of water to replace that sweat, is worth considering.

Diplomatic Mike
(MikefaeDundee)

Locale: Under a bush in Scotland
It's a matter of climate on 10/27/2011 11:49:56 MDT Print View

Another thing to think about.
Like many on here, i don't carry spare clothing (apart from an insulating layer), and sleep in what i am wearing. I include my clothing as part of my sleeping system. If i allow myself to get more than damp, i could be in for a cold night.
I realise that this probably sounds stupid to folk who hike in dry climates.

Oliver Nissen
(olivernissen) - MLife

Locale: Yorkshire Dales
Updated... on 10/27/2011 16:28:01 MDT Print View

Finally fully updated the comments I posted earlier. I went on a bit eh!?

Conversation does seem always to go back to what is best practice... and everyone reverts to their anecdotes. As I'd suggested before, I'd like to see more hard data being gathered to give us a better idea of what's going on.

The question that vexes me the most regards the wideish range of temperatures recorded inside the jackets. Is that purely caused by lower breathability putting greater heat-stress on Will, or do some of the jackets naturally have higher internal convection, radiative heat transfer, etc. (in the ways I suggested in my previous comments), or are other factors at work I've missed out?

Without improved understanding of what's going on fabrics and membranes might get better but product design isn't.

Stuart Allie
(stuart.allie)

Locale: Australia
Re: DWR treatment on 10/27/2011 17:29:11 MDT Print View

Chris Townsend wrote: "When the DWR treatment wets out the WPB membrane doesn't breathe as well so condensation build-up inside is greater. But the WPB membrane remains waterproof."

Unfortunately this is false. It is a long-standing claim that originated with Gore and is just marketing, not fact. It has been repeated by so many people so many times that it has become an article of faith, but it just ain't true.

When a WPB fabric wets out due to failed DWR, water *will* leak through the membrane. And it gets worse as the fabric gets folded/bent/worn with time. (It's possible that brand spanking new fabric straight from the factory wouldn't do this but that's hardly relevant to the real world.) I've seen this happen with several different jackets and have tested it myself.

I'd love to see Richard or one of the others here with hydrostatic head test equipment demonstrate this.

David Chenault
(DaveC) - BPL Staff - F

Locale: Crown of the Continent
leaky membranes on 10/27/2011 17:35:16 MDT Print View

Stuart, I'd like to here more about the science behind WPB membranes working in reverse.

Reason being, I've certainly gotten quite damp inside my WPB shell during all-day rain. Problem is, it's rather impossible to judge the source.

a b
(Ice-axe)
99 cent poached wiener wurst on 10/27/2011 18:31:29 MDT Print View

In September of 2009 I arrived in the little resort of Stehekin Washington. Having just hiked through three straight days of rain through Glacier peak wilderness on the PCT.
I had never been this wet in my life. All my gear, clothes, spare socks, everything was sopping wet.
I was embarassed and felt I had somehow "failed" even though I had used all the outdoor skills of 18 years of hiking as well as the past 5 months spent walking from Mexico.
It was hilarious when i met up with a large group of fellow PCT hikers and discovered that every single person, despite what they had for rain gear; ponchos, expensive WPB jackets, cheap dri ducks.. every one of us was completely soaked to the bone.
The more seasoned long distance hikers simply used a wind shirt and umbrella.
No, they don't stay dry either. The windshirt gets wet and the umbrella slows the replacement of that warm moisture (warmed by body heat) with the cold rain thats falling.
For sitting around camp the high techery works great.
For hiking all day, everyday, through the rain expect to get wet.
There is a saying among long distance hikers:
The only cure for three days of rain is a motel room.
I am not alone in coming to the conclusion that a simple 99 cent plastic poncho is as effective as any 300 dollar WPB jacket at keeping a person dry or rather less wet during multi day rain.

Dave U
(FamilyGuy) - F

Locale: Rockies
Re: 99 cent poached wiener wurst on 10/27/2011 18:33:48 MDT Print View

I don't think that the membrane is leaking. What is happening is that the wetness is body sweat and condensation when the DWR fails. At least this has been my experience.

Carter Young
(kidcobalt) - M

Locale: Western Montana
About Wetted-Out Shells Leaking on 10/27/2011 20:29:56 MDT Print View

I don't believe that the total saturation of the outer layer of a WP/B shell (or other item) leads to a reverse passage of water from the outside to the inside. For example, I have several single-walled WP/B tents (from Bibler, ID, and Nemo), and they certainly don't leak through the fabric even when the outside is entirely wetted-out (rain water no longer beads). And what about fishing waders that are constantly immersed in water? They don't leak through the fabric, and are undeniably more comfortable to wear than non-breathable, but waterproof, alternatives.

Stuart Allie
(stuart.allie)

Locale: Australia
Re: leaky membranes on 10/27/2011 20:51:56 MDT Print View

@David,

I've only ever found one article that explained this in great detail and had lab test to show it, but it was a print article from over 10 years ago. I haven't been able to locate it or any similar reports on the web.

It's interesting to try and find any lab tests that actually support Gore's claim that the wetness you get when the DWR fails in solely from perspiration and not from external water leaking through. I haven't been able to locate a single report that backs their claim. As far as I can tell the origin of the claim is Gore's marketing department.

I will have another look around the web to try and find some science to backup my statements.

I have tested it myself though. A goretex jacket with the DWR well and truly removed (it went through the washer twice with detergent...). I draped the jacket over a bucket and filled the depression with water. And couple of hours later, there was about half an inch of water in the bottom of the bucket. I'm pretty sure the bucket wasn't perspiring :) After a good wash-in DWR treatment, the same test produced no water in the bucket.

I've done this with two other jackets, one gore-tex (>10 years old, had never had its DWR renewed apparently) and the other some proprietary goretex-like membrane. Same results.

Anecdotally, I've had DWR-less goretex let heaps of water through the shoulders with me just standing in the (heavy) rain for a couple of hours - there was no sweating going on (yes, I know about insensible perspiration - it is insufficient to explain the amount of water that got through.)

I'm always surprised when people repeat Gore's claim about this. I just assumed everybody knew it was just spin.

Cheers

Dave U
(FamilyGuy) - F

Locale: Rockies
Re: Re: leaky membranes on 10/27/2011 20:58:25 MDT Print View

@Stuart - your experience certainly suggests that the fabric is leaking. I have had gortex paclite wet out under extreme (rain) duress, but I have not had it leak. I have also had internal condensation that could have been assumed to be leaking through except that the rain was cold and the internal moisture was very warm.

This definitely calls for some scientific analysis by BPL!

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: About Wetted-Out Shells Leaking on 10/27/2011 23:05:37 MDT Print View

Consider that the membrane may simply be overwhelmed with perspiration as well as the shell wetting out and about the same time. The relative humidity is also increasing as the air is saturated after hours of rain--- everything is soaked inside and out and the whole system spirals into a soggy mess.

As Matt found out in Stehekin, after that many days of rain, the cold moist air has permeated everything-- the air, ground, foliage, your gear and clothing. And you're working hard, hauling your load in steep terrain. There is a real difference in moisture management with hours or days of cold drizzle in saturated landscape vs something like a thunderstorm in an otherwise dry environment.

Jay Cable
(spruceboy) - F
.. on 10/28/2011 01:35:31 MDT Print View

Could someone explain how a wpb membrane like goretex could "reverse" and let water in?

I am a bit skeptical, as I have used goretex and goretex knock off dry suits and paddle pants while immersed in water and didn't notice any leakage. It would seem if the only thing preventing the wpb membrane from reversing is the dnr coating then I should get wet, yet I don't, as the coating is completely "wetted" out while underwater.

Is it possible that the folks are just noticing that when the surface of the fabric is wet it no longer allows moisture out? Or am I completely missing what people mean by the membrane "reversing".

It would seem like this would be an easy thing to test out..

Great article by the way.

Andy Davison
(FurTech) - M
Re: Re: leaky membranes on 10/28/2011 05:48:06 MDT Print View

Many thanks for the article and all the interesting comments. Excellent stuff.

I was intrigued by the GoreTex over a bucket test. It's interesting to note that during a hydrostatic head test the outer fabric is saturated yet results can be >20000mmH2O. But here we are talking about leaking over longer time frames.
Could it be that the water from the puddle on top of the membrane is evaporating through the membrane and condensing on the lining? I say this on the basis that condensation occurs not just because of the dew point conditions (temperature, humidity and pressure) but because of the water repellency (surface energy) of the material. The hydrophylic PU layer may have this effect but a scrim lining with washed out DWR would play a similar role.
In the case of waders there's a temperature gradient that may be counteracting this effect and the time scales are different, too.
It's important to realise that water attaches to hydrophobic surfaces, unless they are superhydrophobic, like a lotus leaf (Cassie-Baxter conditions), and that small forces such as gravity or even subtle shaking (of the floor?) may allow droplets to spread out, possibly allowing water to creap through pores in a membrane. This situation can be seen in the lab when droplets on a hydrophobic surface slowly spread out over time.
Alternatively, a simpler explanation may be that the membranes were damaged, physically or by chemical contamination, in all the tests carried out.

Andy Davison
(FurTech) - M
Re: 99 cent poached wiener wurst on 10/28/2011 06:08:26 MDT Print View

Quite right!
I add this comment because it seems to be pertinent to breathability in the rain:
Some people contend that when ambient humidity is 100% no breathability occurs. On the face of it that's true, except where you can warm the air enough for it to absorb some moisture and then wisk it away on a breeze; or in the down wind part of your clothing system where the aerodynamics create a low pressure zone, allowing the air to absorb more moisture than the ambient conditions. So wind and heat loss seem to me to be the key ingredients. But, of course, it's so much easier to get wet than to dry off, and harder to dry in high humidity conditions.
But getting wet's not going to kill you, it's staying warm that's important (thinking: mmmmm, hot bath). By the way, the Blizzard Reflexcell kit provides insulation that is far less effected by water than conventional garments.

Roman Vazhnov
(joarr) - MLife

Locale: Russia
do we need WPB on 10/28/2011 06:33:43 MDT Print View

As everybody knows here, current WPB technologies are not perfect. Nevertheless today practically only WPB (and may be Paramo garments) provides acceptable function balance in certain areas. Of course we can use silnylon ponchos in lightweight backpacking (i use poncho too), but there are circumstances when we can not. For example mountaineering, canyoning, kayaking, biking. And of course there are backpackers who simply don't like to use ponchos. So it is good to know what WPB technlogy is better. And i think that the main focus of this article is to compare membranes and not to make claim that they all are crap. Besides, technologies are not standing still, progress is good.
It would be interesting for me to make this test with really breathable soft\wind shells (something like Dryskin or Pertex equilibrium) and with Paramo. Big thanks again, BPL, i can't buy all such jackets to do the tests by myself :) Though it would be fun.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: leaky membranes on 10/28/2011 09:05:24 MDT Print View

Maybe it doesn't matter whether it leaks or it's sweat

If it's raining, I'll get wet

Plan B is to wear as little as possible, then when I quit hiking it will quickly dry out

I have found eVent and GoreTex to dry pretty quickly when I get out of rain and quit hiking

Ayumi Obinata
(plassy) - F
Lab Test on 10/28/2011 09:48:48 MDT Print View

This is one of the most interesting WPB test I've ever seen. It's a great start to decipher this voodoo technologies.

As Oliver commented, I also think the test is not perfect, but it seems like there is no scientifically perfect method to test WPB jacket so far anyway. Since the temp and humidity is probably not only affected by membrane by itself but also affected by zipper, size and length (also as Oliver mentioned), and the design philosophy of each jacket seems to be a bit different each other, so I would like to see the pure lab test result of each membrane performance exactly in the same lab condition, although the question is what kind of condition is more practical for lab test.

I also would like to see the lab test result of the endurance of DWR and the zipper/seam leakage of the major players.

Edited by plassy on 10/28/2011 09:59:39 MDT.

Dave U
(FamilyGuy) - F

Locale: Rockies
Re: Re: leaky membranes on 10/28/2011 10:29:08 MDT Print View

"Maybe it doesn't matter whether it leaks or it's sweat

If it's raining, I'll get wet"

There are two types of wet. A warm wet, and a really cold wet. Which do you prefer?

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: leaky membranes on 10/28/2011 11:26:57 MDT Print View

I think the amount of water is so small that the BTUs it takes to heat it up are infintesimal, so it doesn't matter whether it's sweat or rain water.

It takes 1150 BTU/lb to evaporate water from 32F

It takes (85-32) = 53 BTU/lb to heat water from 32F (assuming your rain water is 32F just for example) to 85F (which is what I've measured my skin temperature when I'm cold).

Then it takes 1097 BTU/lb to evaporate water from 85F.

So it takes about 20 times as much heat to dry out your clothes, than to heat up them up from cold rain water.

Conclusion - I don't think it makes much difference whether your clothes get wet from sweat or rain, but drying them out with your body heat will make you cold.

Diplomatic Mike
(MikefaeDundee)

Locale: Under a bush in Scotland
Warm'n wet. on 10/28/2011 11:59:04 MDT Print View

I don't think Dave was commenting on drying clothes. He was simply saying it is more comfortable to be warm and damp, than cold and damp, whilst actually hiking.

And safer.

eric chan
(bearbreeder) - F - M
wet on 10/28/2011 12:04:49 MDT Print View

if yr moving youll heat up quickly anyways

as jerry points out ... its when yr stopped or moving at a very slow pace when yr effed ... the evaporative cooling really takes effect

Dave U
(FamilyGuy) - F

Locale: Rockies
Re: wet on 10/28/2011 12:12:55 MDT Print View

Yes - Mike simplified what I was trying to say.

I disagree that the net effect is the same. Having been in some incredibly cold rain in temps close to freezing, I would much prefer a little bit of warm sweat to deal with. I would have a base layer on wicking up the sweat and although it is always a challenge to maintain core temps in such conditions, the temperature difference between the sweat and cold rain would be noticeable and the net negative effect on your core temperature would be greater. Any sort of arm chair science aside (and I say this in good humor), my experience suggests otherwise.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: Re: wet on 10/28/2011 12:17:42 MDT Print View

I'll have to weigh my clothes when damp and calculate how many BTUs required

And compare that to BTUs required to stay warm

Are you calling me an arm chair scientist? Well, I am sitting on a couch...

Dave U
(FamilyGuy) - F

Locale: Rockies
Re: Re: Re: wet on 10/28/2011 12:29:08 MDT Print View

I am going to edit that because it didn't come out right. I am the arm chair scientist. And a bad one at that. I can only go by my experience.

Diplomatic Mike
(MikefaeDundee)

Locale: Under a bush in Scotland
Wet on 10/28/2011 12:37:11 MDT Print View

Seriously, hiking in near freezing rain is one of the most difficult conditions a hiker can face. Unless you have dealt with conditions like that for days (weeks) on end, it can be difficult to imagine. A oouple of times in the past i've nearly went down with hypothermia. Luckily i wasn't hiking solo at the time. I've had US family come here on vacation, and they have struggled with the weather. I guess folk from the NW of the US and Canada get the same conditions.
Here in Scotland, we do get the occasional high pressure zone in winter. Temps can drop to minus 29C, and the weather is clear and dry. It is pretty simple to deal with conditions like that.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: wet on 10/28/2011 12:59:39 MDT Print View

"I am going to edit that because it didn't come out right. I am the arm chair scientist. And a bad one at that. I can only go by my experience."

Don't worry about it, you didn't say anything offensive : )

Anyway, not possible to unring a bell.

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: Re: Re: wet on 10/28/2011 13:12:09 MDT Print View

It seems to be a consensus that there is no magic with rain shells. It looks similar to waterproof shoes to me, with the industry leaning heavily to the marketing hype.

Okay, assume you will get wet under your rain shell. You stop hiking and there you stand, it is 45F and you are tired and wet and starting to get chilled. Assuming that it isn't pouring, you get a dry layer out of your pack.... but UL principles lean to not carrying spares, or mid layers that might be base-layer substitutes. Oops! Many UL gear lists would have something like a Thermawrap or a light down sweater for insulation, with no spare base layer. I don't like that idea.

This is one of those scenarios where I think light fleece or other stretchy synthetic mid-layers are great. Power Stretch is my favorite, but there are tons of options, from basic 100w fleece to R1, Capilene 2/3/4 and so on. If I have stopped and find my base layer beyond redemption and I am cold, peeling and using my mid-layer for a long stop or camp would be my plan. The base layer might dry if I can get it under cover and a breeze, or a little warmth off a fire if possible. If it isn't soaked it will dry from my body heat-- if I don't get too cold trying to do that. Having a second base layer might be in the works too.

My point is that the rest of your clothing should assume that your rain gear isn't going to keep you completely dry, particularly in those scenarios where you are exposed to hours of cold drizzle and high humidity. Remember that long-term cold drizzle equals no direct sun, perhaps for days, so there is little opportunity for drying anything.

What is your solution?


Typical PNW weather: Lake Annette, Washington, July 4, 2010, 2PM PDT, elevation 3600', 49F, 95% humidity. There was a heavy rainfall a couple hours later, followed with hours of light drizzle and cold air from the snow fields above.
Cascade un-sun

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: Wet on 10/28/2011 13:18:20 MDT Print View

Mike Reid wrote about Scotland: "I guess folk from the NW of the US and Canada get the same conditions."

Aye, it is a cool, dewy wonderland :) I think the Scots have more exposed conditions, whereas I can often hide in the trees. You must need some tough tents in Scotland!

Edited by dwambaugh on 10/28/2011 13:19:55 MDT.

David Olsen
(oware)

Locale: Steptoe Butte
Re: Re: Re: Re: wet on 10/28/2011 13:20:07 MDT Print View

What is your solution?


Typical PNW weather: Lake Annette, Washington, July 4, 2010, 2PM PDT, elevation 3600', 49F, 95% humidity. There was a heavy rainfall a couple hours later, followed with hours of light drizzle and cold air from the snow fields above.

After hiking is done?

1. Put up tarp

2. Change base layer and add other layers over.

3. Start stove or fire

4. Eat, and drink hot drinks.

Diplomatic Mike
(MikefaeDundee)

Locale: Under a bush in Scotland
Wet again on 10/28/2011 13:25:45 MDT Print View

Good post Dale.
I often read on the forum about folk getting wet, then drying their gear later. Sometimes i have to laugh! How do you dry your gear in continuous rain?
Fleece is hardly mentioned on here, but it is a mainstay of a Scots hiking gear. It doesn't absorb water, and it doesn't collapse when wet.

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: Wet again and fleece on 10/28/2011 13:33:36 MDT Print View

Same with sleeping gear-- people writing about laying their down bag out to dry on a break. HAH!

Fleece (aka pile) was developed for North Sea fishermen to wear-- under non-breathable rain gear too. It is a mainstay of NW hikers as well. The weight isn't so bad, but the bulk is a pain.

Diplomatic Mike
(MikefaeDundee)

Locale: Under a bush in Scotland
Fleece on 10/28/2011 13:42:51 MDT Print View

Fleece was actually developed for North Sea oil workers to cope with the wet/cold. Probably because it was cheap. Fishermen used to supply the stand-by safety boats, and wore them too. I used to work on the North Sea oil rigs, and was very popular amongst my hiking friends. :)
It was originally only available in a dark blue colour. I assume that was the colour it came out in 'the mix'.

Diplomatic Mike
(MikefaeDundee)

Locale: Under a bush in Scotland
Fleece and beer on 10/28/2011 13:45:37 MDT Print View

My apologies for drifting the thread.
My excuse is the time difference. I've had a couple of beers. )

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: Re: Wet again and fleece on 10/28/2011 13:50:10 MDT Print View

"What is your solution?"

I have hiked in the PNW many times where I was somewhat wet after hiking - worst case is 32F and raining (and windy).

Wear base layer and eVent jacket while hiking that get somewhat wet inside.

Get tent up. Get inside. I'm pretty dry within one hour, during which time I have residual heat which keeps me somewhat warm. Also, I'm still moving around setting stuff up, eating. At some point put on insulated vest, hopefully my other stuff isn't too wet at that point.

Diplomatic Mike
(MikefaeDundee)

Locale: Under a bush in Scotland
Re wet again and fleece. on 10/28/2011 14:07:51 MDT Print View

Everything you are wearing is wet. Continuous rain, even as you pitch your tent/shelter/tarp.
You set up your tent, and crawl inside. Your sleeping bag/quilt is dry, because you have used a drybag inside a packliner. You cook your meal inside your shelter. You can't cook outside, as the rain and 50mph wind would cause a slight inconvenience. The steam from your cooking adds to the 100% humidity. All your wet clothing adds to the moist mix in your tent.
You wake in the morning, dry and warm inside a cold sauna.
Try to get your bag/quilt packed away without touching the wet tent walls. Pack up your gear, trying to shake at least 5 pints of the water out of your tent. Squash everything into your pack.
Pitch the next night and do it again.
Lovely. )

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Hybrid rain jackets? on 10/28/2011 14:34:19 MDT Print View

I ran across an REI Airflyte eVent jacket yesterday that is designed for runners. I would call it a hybrid design as is has mesh/stretch underarm vents-- the pockets can vent too. Surprisingly, it weighs about the same as my Patagonia Rain Shadow jacket that has a hood (13.4oz vs. 13.6).

Anyone have experience or comments? I'm liking the ventilation, at least on paper.
I wonder if it is a practical hiking design with those panels? It seems that it would be good for day hikes and light rain. I can get by without a hood, although I would add one to the "perfect" design.

REI Airflyte jacket

eric chan
(bearbreeder) - F - M
more wet on 10/28/2011 15:27:26 MDT Print View

Okay, assume you will get wet under your rain shell. You stop hiking and there you stand, it is 45F and you are tired and wet and starting to get chilled. Assuming that it isn't pouring, you get a dry layer out of your pack.... but UL principles lean to not carrying spares, or mid layers that might be base-layer substitutes. Oops! Many UL gear lists would have something like a Thermawrap or a light down sweater for insulation, with no spare base layer. I don't like that idea.

This is one of those scenarios where I think light fleece or other stretchy synthetic mid-layers are great. Power Stretch is my favorite, but there are tons of options, from basic 100w fleece to R1, Capilene 2/3/4 and so on. If I have stopped and find my base layer beyond redemption and I am cold, peeling and using my mid-layer for a long stop or camp would be my plan. The base layer might dry if I can get it under cover and a breeze, or a little warmth off a fire if possible. If it isn't soaked it will dry from my body heat-- if I don't get too cold trying to do that. Having a second base layer might be in the works too.


1. IMO there are two ways to get somewhat less damp at the end of the day ... spare base layers ... or using body heat and hawt nalgene to push the moisture out (which requires extra fuel and over calculating yr insulation) ... or both ... neither is "UL" ... base layers need to be as thin and form fitting as possible to facilitate drying and wicking ...

2. fleece is the "best" for wet conditions despite all the hype about synthetic insulation ... it breathes well, has a fuzzy interior that "feels" less damp, and dries very quickly ... synthetic insulation has 2 nylon shells that need to dry out as well as the primaloft in the middle ... it also collapses more than fleece in truly wet conditions, it works for stops and in camp, but you should be careful not to get it truly soaked ... i wont even talk about down as we know that in 50% humidity 900 fill aint 900 fill, never mind 100% humidity

3. as mentioned its when yr stopped when you truly have to worry ... most people can generate enough heat or even too much with a base/light fleece/rainshell on the move ... but stop, and i dont care if yr warm wet or cold wet ... itll all become cold wet very quickly if you cant get under shelter and get more insulation on you ... or a fire

4. the trick IMO is wearing as little as you can on the move and the quickest drying things you can find ... that way theres less moisture in the system from the body, and less things to get soaked ... and dont stop for any real length of time till the end of the day ... if you do find yrself stopping often such as on more technical ground, have a light fleece underneath and control yr exertion levels

one thing i disagree with is using a windshirt here in light rain here .. unless you know it wont last very long, yr windshirt will get soaked and then the layers underneath ... much of the time in the PNW drizzle lasts for days on end ... better to put on a rain shell, wear little under it and use the zippers for temp control ... a good synth base will actually dry to just damp if yr moving as the body heat will push out some moisture with good ventilation

at the end of the day just remember that its all about the big 3 ... not the BPL ones ... but what they taught you in school ... fire (warmth including insulating clothing and hawt nalgenes), shelter (get the hell outta the rain), and food (including water, burn those calories) ...

Chris Townsend
(Christownsend) - MLife

Locale: Cairngorms National Park
Re: Re: Wet again and fleece on 10/28/2011 15:48:21 MDT Print View

Here in Scotland most hiking is in open country and as well as often wet it's also often very windy so it's not just rain you have to deal with but rain blasted horizontally at you by the wind. And, as Mike says, this can last for days or even weeks, even in summer. A showerproof garment, however good the DWR, just means you'll get soaked to the skin pretty quickly. You'll be cold too with that wind whipping away any residual heat. A waterproof shell and fast drying insulation is essential. Feeling warm and damp from sweat is much safer than getting cold and wet through rain, as well as much more comfortable. Of course insulation is needed for any rest stops and in camp.

In the coldest weather - roughly from when it starts to cool down in October to whenever it starts to warm up in April - I wear a merino wool base layer and a Paramo jacket and carry a synthetic insulated top big enough to don over the Paramo when I stop. I also carry a thin fleece as additional camp wear and to wear between the merino and Paramo if it's really cold. During the warmer months - when it can be just as wet and almost as windy as winter - I wear a membrane shell as I find Paramo too warm then plus a merino base layer and carry a thin fleece for warmwear, with a down jacket or vest for tent use in May and September when it can still be frosty if the sky is clear.



As Dale suggests tents need to be good, as they may have to stand up to very strong winds and torrential rain. High humidity means condensation is very likely and in storms you can't usually leave the door or any vents open. So double-skin tents are preferred by most people, though good single-skin ones can work if you choose the right design and know what you're doing.

Martin RJ Carpenter
(MartinCarpenter) - F
Airflyte no hood? on 10/28/2011 15:58:09 MDT Print View

Scary! From your willingness to go without I presume your area doesn't have proper heavy, strongly wind driven rain :) In which case the basic design could work quite well.
(No US distribution I'm aware of, but this: http://koppdaniel.wordpress.com/2011/06/24/preview-haglofs-intense-2012-2/ does seem a rather better implementation of this sort of idea.).

If risking wind driven rain something with extra long pit zips/side vents or some such seems rather saner.

Inaki Diaz de Etura
(inaki) - MLife

Locale: Iberia highlands
Re: Wet again and fleece on 10/28/2011 17:31:46 MDT Print View

Fleece got back into my 3 season list for the very same reasons you all mention AND when I realised (as obvious as it may be) that it can also be lightweight and not particularly bulky. I use a tight fitting top which actually looks more like a shirt and can work both over a base layer or as a base layer itself. It weights the same as a typical polyester base layer (187 gr. in a M) and fits nicely in a 5 layer scheme (base, fleece, windshirt, high loft insulation and waterproof shell) which can work for virtually any 3 season conditions. The nice thing is just that: the fleece does not take the place of any other layer, it's one more layer with a precise function distinctive from the others and a wide number of possible combinations with the other layers to meet the conditions. Using fleece does not negate UL.
Interesting thread drift. The lightweight phylosophy is all about synergies anyway.

Edited by inaki on 10/28/2011 17:38:45 MDT.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: more wet on 10/28/2011 19:19:48 MDT Print View

"the trick IMO is wearing as little as you can on the move and the quickest drying things you can find"

and if the "as little as you can wear" (base layer plus jacket) doesn't keep you warm, walk faster until you're warm

Dave U
(FamilyGuy) - F

Locale: Rockies
Re: Re: more wet on 10/28/2011 19:47:53 MDT Print View

...except you have to stop eventually.

Anyone ever use a Packa as a rain garment and could comment on whether it works well with respect to moving body moisture out?

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: Airflyte no hood? on 10/28/2011 20:41:38 MDT Print View

Martin pointed out, "Scary! From your willingness to go without I presume your area doesn't have proper heavy, strongly wind driven rain :) In which case the basic design could work quite well."

In my mind, I was assuming the long hours of cold/humid/drizzle/wet brush in heavy forest rather than wind-driven downpours above treeline. There are times when a little wind would be welcome! I am thinking more of day hikes, and the possibility of a drier, more comfortable trip extends my hiking season quite a bit.

With few exceptions, heavy downpours are temporary affairs in the PNW. We have pretty good warnings on storms that bring in major precip--- and I'm staying home :) If there is the possibility of heavy weather, I have the standard rain parka with hood.

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: Re: Wet again and fleece on 10/28/2011 20:53:24 MDT Print View

"Interesting thread drift. The lightweight phylosophy is all about synergies anyway."

Well put. Once you have the data, you can act on it and make improvements. I like being warm and dry, I'm just funny that way ;)

Roman Vazhnov
(joarr) - MLife

Locale: Russia
wet insulation on 10/29/2011 01:30:08 MDT Print View

Interesting thread drift.
Did anybody have used Paramo fleece and synth insulation (Summit Hoodie, Torres Jacket) in wet conditions? Were they better than conventional fleece? (The same question for Climashield Apex).

Edited by joarr on 10/29/2011 01:30:47 MDT.

Barry Cuthbert
(nzbazza) - MLife

Locale: New Zealand
Re: Re wet again and fleece. on 10/29/2011 01:34:39 MDT Print View

Mike said:
"Everything you are wearing is wet. Continuous rain, even as you pitch your tent/shelter/tarp.
You set up your tent, and crawl inside. Your sleeping bag/quilt is dry, because you have used a drybag inside a packliner. You cook your meal inside your shelter. You can't cook outside, as the rain and 50mph wind would cause a slight inconvenience. The steam from your cooking adds to the 100% humidity. All your wet clothing adds to the moist mix in your tent.
You wake in the morning, dry and warm inside a cold sauna.
Try to get your bag/quilt packed away without touching the wet tent walls. Pack up your gear, trying to shake at least 5 pints of the water out of your tent. Squash everything into your pack.
Pitch the next night and do it again.
Lovely. )"

You've described New Zealand conditions very well too.

Wild Exped
(bankse) - MLife

Locale: Tasmania (down under downunder)
ha ha on 10/29/2011 01:50:30 MDT Print View

yer, sounds familiar. I use a tarp for a few months each year but mostly due to heavy packs (and needing to fit 12 people somewhere for meals) I keep reading stories on here of the light weights and imagining that i might try one by choice for private walks. Sometimes its easy to forget what freezing, continuous, wind blown rain is like from my house on the coast ; )

Tenting, all ive found that works is to try to keep the wet stuff taken in to a minimum. Wear very little walking, suffer putting that wet stuff back on in the morning. A quick rinse in hot water (socks) makes this part bearable. All the other little tricks mentioned help but not much seems to help a rain shell. I use event and the pace needs to be dead slow to stop perspiration in the hills, temperature drops in the evening so a system for getting dry (without getting everything in a tent wet) asap, once stopped, is vital.

Windshirts sound like a good option but they would be mostly gaffa tape soon enough.

Edited by bankse on 10/29/2011 01:56:32 MDT.

John Pasmore
(jpasmore)

Locale: NYC
Wet Insulation | Staying Dry on 10/29/2011 07:16:02 MDT Print View

Foul weather gear in sailing is generally too heavy for "hiking" but that's my next test. My Marmot shell was no match for a November squall during a boat delivery -- wet through is an understatement. 100% waterproof clothing and just vent where you can -- I would much rather deal with a little condensation than a lot of rain.

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: Wet Insulation | Staying Dry on 10/29/2011 08:20:30 MDT Print View

I remember talk of breathable membranes and salt water being a bad mix, but was never able to take it beyond urban myth.

There is a lot of light PU-coated stuff out there and it is relatively inexpensive too, like Red Ledge, Sierra Designs, Helly Hansen, and house brands like Campmor.

Edited by dwambaugh on 10/29/2011 08:33:23 MDT.

Brett Peugh
(bpeugh) - F - M

Locale: Midwest
there must be an easier way. on 10/30/2011 08:05:06 MDT Print View

I actually purchased a membership finally so I could read this article. I think I am going down the same line as a few of the other posters as to why pay the hundreds of dollars for a jacket that will only last maybe 5 years for marginally better performance? And since I am one off those tall people my options are even more limited. I guess just find something lightweight that is more durable than DriDucks on sale, waterproof the heck out of it, lean over once in awhile and pull the zipper down to vent from the front.

David Chenault
(DaveC) - BPL Staff - F

Locale: Crown of the Continent
the easier way on 10/30/2011 10:15:18 MDT Print View

David U, as I commented earlier in this thread I tested a Packa against a G-tex and PU shell this spring. Even with the baggy fit and monster pit zips I found the Packa retained substantially more moisture than the other two (hiking fastish in cool, humid weather). Neither of the WPB garments (Haglofs Ozo, Marmot Essence) had pit zips. The tops of my shoulders down to my elbows got soaked from the inside in a way I've never had happen with a WPB coat. Folks who hike slower and perspire less might not find this to be the case. My conclusion was for me, the Packa and comparable rainwear is pretty useless.

jeffrey armbruster
(book) - M

Locale: Northern California
field testing wp jackets on 10/30/2011 10:44:00 MDT Print View

Many years ago I bought an early iteration or REI's three-ply event jacket. It was on sale for next to nothing but I could only get an extra large. I usually wear a medium. Even when I would nordic ski in the thing it didn't really wet out from inside--remembering that this is in cold snowy conditions and I would leave some front zip open. The point being: I feel that the bagginess resulted in less sweating out from inside. There was also a loss of heat retention. Maybe if you want to reduce interior wetness, size way up and pay the price in warmth loss and looks.

Dave U
(FamilyGuy) - F

Locale: Rockies
Re: the easier way on 10/30/2011 11:04:50 MDT Print View

@David C - thanks for the input. Most helpful.

eric chan
(bearbreeder) - F - M
stoic on 10/30/2011 11:33:18 MDT Print View

im absolutely amazed that no one has commended that the stoic vaporshell tested to the top of the pack ... there was quite a bit of controversy on the forums when it came out about its breathability ... looks like it might be quite breathable ... sure it weights 14 oz ...

but they are $90 on sale right now if yr sized large and above ... i need a medium unfortunately

when yr paying $90 (or $129 regular price) vs. the same or better performance vs some of these $300+ shells ... you have to really ask yourself what are you really getting ... ive hear backcountry has a great warranty so it cant be that ... hmmm

i think its quite eye opening at what price a good WPB shell with the same performance of "top brands" can sell for once you take out a lot of the marketing and "brand premium"

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: field testing wp jackets on 10/30/2011 11:39:56 MDT Print View

"It was on sale for next to nothing but I could only get an extra large. I usually wear a medium."

That may be the "bellows effect." I can see how a larger jacket might move some air in and out as the user moves their arms and bends, but I've never seen it tested. That should be simple enough to test: just wear the same jacket in various sizes. If that is a factor, then I wonder how trekking pole use would effect the mix. I would really like to see size tested on non-breathable jackets. Ponchos and windshirt/umbrella mixes should be tested too.

Stuart R
(Scunnered) - F

Locale: Scotland
Re: Re wet again and fleece. on 10/30/2011 14:38:12 MDT Print View

Mike said "Everything you are wearing is wet. Continuous rain, even as you pitch your tent/shelter/tarp. You set up your tent, and crawl inside. Your sleeping bag/quilt is dry, because you have used a drybag inside a packliner. You cook your meal inside your shelter. You can't cook outside, as the rain and 50mph wind would cause a slight inconvenience. The steam from your cooking adds to the 100% humidity. All your wet clothing adds to the moist mix in your tent."

That's in summer. In winter it's much the same, but a few degrees either side of freezing.
I always keep a dry set of Helly thermals for wearing in my sleeping bag. In the morning I take them off and put all my wet clothes back on again. They're cold but you soon warm up when you get going. Fleece is great, even if it gets soaking most of the water can be wrung out and then it provides good insulation.

Andy Davison
(FurTech) - M
Re: field testing wp jackets on 10/31/2011 05:16:33 MDT Print View

Jeffrey wrote "I feel that the bagginess resulted in less sweating out from inside."

I too have noticed that oversized garments are more comfortable.
I read a PhD thesis (carried out at Leeds University) testing all sorts of shells around a walking route and measuring the temperature and humidity inside, much like the test done here. The author's conclusion was that the spare volume inside the jacket makes a big difference, probably because it creates a reservoir for humidity which takes time to pass through the fabric. This may be more relevant to undulating walks where the humidity created in the short uphill sections is dissipated in the easy sections. It seems to me that baggy garments are likely to allow humidity generated in sweaty areas to move to areas with less humidity and maybe fabric movement pumps air around, too.
I'm curious to know if the XL Montane jacket used in the tests had more volume than the others as this may help explain its excellent performance on the undulating walk?

Edited by FurTech on 10/31/2011 06:27:22 MDT.

Samuel C. Farrington
(scfhome) - M

Locale: Chocorua NH, USA
WPBs on 11/08/2011 23:16:46 MST Print View

About the discussion over WPBs when the DWR fails: I don't know if failure of the outer DWR treatment will allow leakage; but using detergent is not the way to find out. Detergents and many other substances will 'contaminate' the WPB membrane and allow water to come through. I once did this by spraying a silicone spray on an early edition of Danner GTX fabric boots - they leaked so badly just from high, wet grass, it seemed like they were not just failing, but actually attracting the water. This subject was discussed in Alan Dixon's article here:

http://www.backpackinglight.com/cgi-bin/backpackinglight/00316.html

I do know, as several of the above posts point out, that failure of the DWR treatment, and the resulting 'wetting out' of the garment will prevent water vapor from passing through it, and eventually cause the wearer to be soaked with moisture from perspiration in many conditions.

Usually such conditions also carry the greater threat of hypothermia, so being soaked from inside can also be dangerous; in that when you are soaked, heat rapidly disperses. Soaking from outside is probably worse, though, because colder water is continually moving from outside, into and through the garment. That's where I agree with David Ure 100%.

I have had several close calls with hypothermia, the worst being in kayaks on large lakes during very cold rains in the fall. While a GTX pull-over, along with a spray skirt, did keep me from being totally sopped after many hours of paddling in the rain, I eventually reached the point where I knew I was in serious trouble and had to get off the water. The second worst situations occurred when hiking for long periods during such rains on open, unprotected ground. Maybe they were not quite so bad, because the hiking kept me warmer than the paddling did. These experiences led me to the following conclusions:

> To become familiar with and aware of signs of seriously developing hypothermia.

> To get out of the rain and into a dry place immediately when these signs occur, even if this totally bollixes up the trekking/tripping schedule.

> To carry enough well-protected dry clothing and sleeping gear to get into and warm me up in the dry place, even though this means carrying more weight than I would like.

> To consume hot food with lots of carbs as soon as possible.

The above are far more important to me than how good a rain shell is. Please give them your serious consideration. Thanks.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: field testing wp jackets on 11/09/2011 02:06:12 MST Print View

> I read a PhD thesis (carried out at Leeds University) testing all sorts of shells
> around a walking route and measuring the temperature and humidity inside, much like
> the test done here. The author's conclusion was that the spare volume inside the
> jacket makes a big difference, probably because it creates a reservoir for humidity

In a PhD thesis???? What was the School - Home Economics????
That (the reservoir idea) has got to be among the most stupid suggestions that I have heard. The physics just isn't there.
What a 'spare volume' does is flap! And that pumps a lot of the humid air out. As Dale rightly said.

Cheers

Edited by rcaffin on 11/09/2011 02:08:05 MST.

Mary D
(hikinggranny) - MLife

Locale: Gateway to Columbia River Gorge
Field Testing Air Permeable Waterproof-Breathable Fabric Technologies – Part 2: on 11/09/2011 12:03:02 MST Print View

I've found that a baggy jacket has more ventilation. In addition, I want my rain jacket big enough to wear over my puffy insulating jacket at rest stops and in camp. Life gets very difficult (and can be threatened) if you can't keep your insulation dry!

I still can't determine enough difference between a "breathable" jacket and a non-breathable jacket to warrant spending the big bucks for the former! And I've had too much expensive Goretex fail where the shoulder straps rub it. If temps are warm, both types of jacket get equally wet inside. I just leave the rain gear off when it's warm and get wet; my baselayer top and hiking pants will dry on my body in 20 minutes. If it's cold, it doesn't seem to matter either.

I do find that pit zips help a little. Leaving the front zipper part-way open helps a lot more. Of course if the rain is coming horizontally from the front, I have to close the front zipper, but usually under those conditions I don't get hot inside!

Thanks for the article, Will! It has confirmed my own experience (or, if you prefer, prejudice) that there is little difference, or at least not enough to be worth the extra money for those "miracle" fabrics.

Andy Davison
(FurTech) - M
Re: Re: Re: field testing wp jackets on 11/09/2011 12:06:51 MST Print View

Quite right, flapping has got to be a big factor, but how much moisture is moved out depends how well the garment is sealed and how much movement there is. I imagine a sack would seal the body of the Montane jacket pretty well, or does the neck closure create a large chimney?
As far as I'm aware the tests I mentioned included Paramo and Buffalo, both of which trap air between the layers and may be less effected by flapping...the PhD (actually it could have been a Masters) was in outdoor clothing or sports clothing, I'm not quite sure of the title.

eric chan
(bearbreeder) - F - M
Re: Re: Re: Re: field testing wp jackets on 11/09/2011 12:10:33 MST Print View

gore i believe requires their active shell be quite form fitting ... the reasoning was that the less dead air the higher the "breathability"

Andy Davison
(FurTech) - M
Re: Re: Re: Re: Re: field testing wp jackets on 11/09/2011 13:41:05 MST Print View

Thanks Eric, I wasn't aware of that. As far as I understand it the rate of breathability will increase when the difference between the inside and outside vapour pressures is greater, so high humidity on the inside should increase the rate of exchange. Also, if the shell is closer to the body it should be warmer, reducing the chances of condensation for a given humidity. But maybe the other reason is just to save weight in the garment?!
Despite all the above, evaporating 100ml of sweat into 1 litre of dry air is going to generate twice the humidity of putting it into 2 litres (though the moisture vapour transfer rate may be higher in the latter case).

Jason Elsworth
(jephoto) - M

Locale: New Zealand
Fleece on 11/09/2011 15:43:40 MST Print View

A light (8.5 oz) tight fitting fleece is usually in my 3 season kit here in NZ. If I don't need it when walking (and I usually don't) then it is great to take off a wet base layer and put it on. I don't like being too reliant on walking at a brisk pace to keep warm, as difficult terrain, tough descents and navigational challenges can often make this impractical. It may go against UL dogma, but it's my insurance.

I would really like to try the Paramo system, but it is expensive, so I will probably stick with an eVent set up that can be used year round. I am also considering moving away from merino base layers to something a bit quicker drying. Recently a combination of light softshell trousers and eVnet over trousers worked really well for my legs. It made me wonder how well a light sofshell jacket (like the RAB alpine) would do under a hardshell in cold, wet weather.

Manuel Espejo
(manuel.espejo) - F

Locale: La Cuchilla de los Santa.
Paramo on 11/14/2011 09:06:42 MST Print View

I usually hike in the Paramo ecosystems near my home in Villamaria, normally don't rain a lot up there, but is high and is the tropic, sometimes the humidity can be 90% or higher, so is imposible to stay dry. I use a lot of systems from windshirt + umbrella system, WPB Jackets, Silnylon ponchos and Paramo waterproofs. with all the systems I become wet in serious rain or with high humidity (a lot of fog. so I prefer the Paramo systems. Yes, at the end I become wet but warm and the garments take little time to dry and is easy to bushwack because there is not a lot of trails here. the only drawback of Paramo clothing is "too warm" for most of the conditions.

P.D: the new formula of Nikwax DWR is more durable.