A Breathable Rainwear Experiment

[Son of a Beach]

Last weekend I carried out an experiment with my Paddy Pallin 'Vista' raincoat which is made of a 'breathable' fabric (goretex in this case) which supposedly allows moisture (such as sweat) to dry inside the jacket and for the vapour to pass through the fabric and escape, preventing excessive build up of moisture inside the jacket. I've always been rather sceptical about how much such fabrics really do 'breath'. Now that I've put it to the test I know the truth!

As anyone in Tasmania would know, it rained a LOT on Saturday night. Well I was at Scott Kilvert Hut (behind Cradle Mountain) that night with a bunch of other people from these forums, and in order to give my raincoat a good test, I left it lying inside-out in a pool of water outside the hut in the open where it was rained on heavily all night, with a bit of snow every now and then for good measure*.

So when my raincoat was eventually located by geoskid the next morning, it was completely sodden inside and out and right through, with a nice sprinkling of soggy snow on it to boot. I shook it out and hung it up again to let it drip dry for a while.

When it came time to leave, I wore my merino thermal, as well as a good polarfleece jacket under the raincoat (as it rained pretty much all the walk out and was quite cold, and because I didn't wat the soggy raincoat making my thermals soggy right from the start of the walk). I very rarely walk wearing so many clothes, but it was a very windy and cold day, and I didn't get hot in this much clothing for more than just a few minutes of a steep uphill section.

After a couple of hours of walking, the raincoat was completely dry on the inside, despite the nearly constant rain during the walk out.

So I now concede that good breathable fabrics do actually allow moisture inside to escape and dry out, even when out in cold and rain.

*Yeah, OK, I actually left it on a hook in the verandah of the hut, but the wind blew it off and deposited it inside-out in the pool of water where it stayed all night

[frank_in_oz]

Good one Nik,
Not sure of the validity of the experiment BUT nicely written up!

My only "objection" would be the thought that the moisture reduced from both the effect of having it against your polarfleece jacket (like wicking) and that you were "warm" and vertical (like a mobile warming / drying cabinet), hence it dried on the inside.

Fair? or bulldust?

[photohiker]

It would be interesting to duplicate the experiment with a 'control' such as someone else wearing a rainbird jacket with the same layers underneath.

[Son of a Beach]

Good one Nik,
Not sure of the validity of the experiment BUT nicely written up!

My only "objection" would be the thought that the moisture reduced from both the effect of having it against your polarfleece jacket (like wicking) and that you were "warm" and vertical (like a mobile warming / drying cabinet), hence it dried on the inside.

Fair? or bulldust?

Yes, this did occur to me. The raincoat was so sodden, that I was wondering if the water would seep right through the polar fleece and make me cold and wet inside my clothes. This did not happen noticeably, but it doesn't mean it didn't happen at all.

Certainly the entire lot dried out during the walk, with no significant moisture remaining in any of my clothing layers. However, I can't be certain that the entire lot went through the fabric, as some could have escaped by openings in the fabric. However, such opportunities were limited, as the weather was cold and wet, and the jacket was closed tightly around my face (and by the pack hip strap) much of the time.

It would be interesting to duplicate the experiment with a 'control' such as someone else wearing a rainbird jacket with the same layers underneath.

Yes, it would be interesting to do such a comparison. But I'm not volunteering to do this in the rain, snow and gale force winds again!

[Penguin]

It would be interesting to duplicate the experiment with a 'control' such as someone else wearing a rainbird jacket with the same layers underneath.

Yes, it would be interesting to do such a comparison. But I'm not volunteering to do this in the rain, snow and gale force winds again!

I did. I was on the hike with SoB and as my "experiment" carried a woven nylon Katmandu raincoat. I was trying to be all clever and light weight.

On the way in, when the weather was not too bad, I wore a polyprop shirt and the rain coat (anorak style) Comfy and no sweat.

On the way out, shirt 100 weight polar-fleece jumper and jacket. Also warm and no sweat. My Jacket was dry on the inside. I would certainly wear a jacket such as this on an open track (no off track work in brush), in cold weather and whee ther was not a heap of up hill. A 520gm weight saving is significant. On the other hand the Ranbird over trousers were useless and my trousers were saturated. So I am looking for a pair of light, WATERPROOF over trousers for similar conditions.

Anything rough or for warmer wet weather - taking the Gortex.

P

[frank_in_oz]

Yes, it would be interesting to do such a comparison. But I'm not volunteering to do this in the rain, snow and gale force winds again!

Toughen up Nik, toughen up! Thought you were a local and used to that sort of weather??

[Son of a Beach]

I did. I was on the hike with SoB and as my "experiment" carried a woven nylon Katmandu raincoat. I was trying to be all clever and light weight.

On the way in, when the weather was not too bad, I wore a polyprop shirt and the rain coat (anorak style) Comfy and no sweat.

On the way out, shirt 100 weight polar-fleece jumper and jacket. Also warm and no sweat. My Jacket was dry on the inside. I would certainly wear a jacket such as this on an open track (no off track work in brush), in cold weather and whee ther was not a heap of up hill. A 520gm weight saving is significant. On the other hand the Ranbird over trousers were useless and my trousers were saturated. So I am looking for a pair of light, WATERPROOF over trousers for similar conditions.

Anything rough or for warmer wet weather - taking the Gortex.

P

But did you soak your jacket inside out in a puddle first?

My jacket was sodden on the inside to start with, from lying in a pool of water all night (and that mesh fabric on the inside holds a lot of water).

[Son of a Beach]

Yes, it would be interesting to do such a comparison. But I'm not volunteering to do this in the rain, snow and gale force winds again!

Toughen up Nik, toughen up! Thought you were a local and used to that sort of weather??

I don't mind walking in that weather (although it's certainly not my preference), but I'm just not volunteering to soak my clothes in water before doing such walking again!

[Penguin]

But did you soak your jacket inside out in a puddle first?

My jacket was sodden on the inside to start with, from lying in a pool of water all night (and that mesh fabric on the inside holds a lot of water).

What interested me was that I thought I would get all sweaty in the non breathing fabric. I did not. Hence my feeling that in cold weather the "breathability" is not as critical. And I sweat easily.

I agree that the Gortex in your case dried from the inside out with time. Impressive.

P

[Son of a Beach]

But did you soak your jacket inside out in a puddle first?

My jacket was sodden on the inside to start with, from lying in a pool of water all night (and that mesh fabric on the inside holds a lot of water).

What interested me was that I thought I would get all sweaty in the non breathing fabric. I did not. Hence my feeling that in cold weather the "breathability" is not as critical. And I sweat easily.

I agree that the Gortex in your case dried from the inside out with time. Impressive.

P

Yes, it is good to hear that a cheaper and lighter fabric is better in this respect than I would have guessed.

[Ent]

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[sthughes]

From that walk:

My OP McMillan leaked a little. Wet in the bottom of the main compartment but not enough to tip out. Similarly wet in the front pocket. Lid pocket dry. It is still fairly new though and I'm told they get more waterproof after a few decent wettings, it is certainly better than the first time I was in wet weather with it.

S2S Pack liner - Brilliant as always, everything kept dry.

MD Overpants (some sort of MD breathable fabric) - Despite using reviveX and ironing it in they do not bead now just 2 walks later. None the less I was 95% dry inside them, so happy enough.

Kmart braces to hold up overpants - load of *&%$#! but did sorta work.

Kathmandu NGX raincoat - I don't know if it was sweat or more likely water but I was drenched above the waist. It has kept me dry in warmer, wetter conditions in the past but not on this walk. It doesn't bead at all anymore so breathability is non existent in the rain. Will try tumble drying it - that's what Kathmandu suggest.

Scarpa Trek Pro boots - Very slow water ingress such that feet get wet but I don't know until I take the boots off. (Apart from when I stepped in water above my knee and it come in over the top - then very slow water egress until I wasn't sloshing in them).

Injinji socks - brilliant, warm feet all the time. Actually I just bought another pair in case these one wear out.

Cheap Polypro themals - fantastic, always warm, smell - what smell!

Icebreaker briefs - Fantastic, never go back to cotton.

[alliecat]

Kathmandu NGX raincoat - I don't know if it was sweat or more likely water but I was drenched above the waist. It has kept me dry in warmer, wetter conditions in the past but not on this walk. It doesn't bead at all anymore so breathability is non existent in the rain. Will try tumble drying it - that's what Kathmandu suggest.

Umm, if the water doesn't bead on it then the DWR has worn off and the jacket will leak. All the WPB membrane fabrics require a functioning DWR not just for breathability but to be waterproof. I don't know where this idea came from that the DWR is just needed for breathability, but it's simply not true. If the water isn't beading, it's time for a new DWR treatment.

Cheers,
Alliecat

[Ent]

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[corvus]

WE Karijini pack only let in moisture through extreme stress point (can be seam sealed) and STS Liner bag was perfect.

Boots AKU other than the full immersion of one ,10 out of 10 and the wet one felt dry after a few minuets (I suspect owing to the Gor-Tex lining) who would have thought!!

Main covering PP Gore-tex Vagabond rain jacket ,full length down to my knees ( jacket has been been revived) perfect other than some wicking up the sleeves ( will re address that area with more"revive" ) hope I can find a replacement as good when I need it.

Overpants are 15 year old Mont Hydronaught been treated to wash and ironing regularly,they got wet around the knees with coat run off but did the job.
At no time did I feel unsafe or uncomfortable other than than my knees

[blacksheep]

Kathmandu NGX raincoat - I don't know if it was sweat or more likely water but I was drenched above the waist. It has kept me dry in warmer, wetter conditions in the past but not on this walk. It doesn't bead at all anymore so breathability is non existent in the rain. Will try tumble drying it - that's what Kathmandu suggest.

Umm, if the water doesn't bead on it then the DWR has worn off and the jacket will leak. All the WPB membrane fabrics require a functioning DWR not just for breathability but to be waterproof. I don't know where this idea came from that the DWR is just needed for breathability, but it's simply not true. If the water isn't beading, it's time for a new DWR treatment.

Cheers,
Alliecat

I think you are quite wrong on this point. DWR is just that- a durable water repellent treatment, completely seperate toany lamination or coating which is used. the function of a DWR is critical to allowing moisture vapour to pass through (especially on inefficient "wet" system,s that use PU like Goretex and hydranaut and NGX). if the face fabric is sturated then there is no humidity gradient to drive moisture through. any perception of wet on the inside is simply sweat condensing on this inside of the fabric.

[sthughes]

I think you are quite wrong on this point. DWR is just that- a durable water repellent treatment, completely seperate toany lamination or coating which is used. the function of a DWR is critical to allowing moisture vapour to pass through (especially on inefficient "wet" system,s that use PU like Goretex and hydranaut and NGX). if the face fabric is sturated then there is no humidity gradient to drive moisture through. any perception of wet on the inside is simply sweat condensing on this inside of the fabric.

thanks for clearing that up - that's what I thought.

So I will take the bait and ask: How does eVent work. I take it that it is not one of these 'wet' systems? I thought after sweat had accumulated inside eVent, it was basically just a better version of the 'wet' system.

[blacksheep]

there is literature all over the web world, but in short, there is nu PU coating, so venting is direct (rather than the condense/absorb/evaporate style of products that use PU (which is most of them, including Gore-tex) . in short -your sweat can pass through A LOT faster, with less driving force (concentration gradient differential) required.
see http://www.eventfabrics.com for some more detail

[sthughes]

Yeah but I mean once the face fabric is saturated and not beading then would breathability not take a massive nose dive like all fabrics?

[blacksheep]

all movement across a (semi )permeable membrane needs a driving force such as a temperature or humidity gradient, and the steeper that gradient the more optimal that rate of movement is. So while the MVTR (moisture vapour transpiration rate) is much higher with eVent than any other rainwear fabric, it will work best when the face fabric is dry (or more correctly, not saturated) so maintaining DWR so that water beads is needed on all "breathable " fabrics.

[sthughes]

That's a YES I take it - Nothing wrong with a one word answer

Thanks, I appreciate the info.

[blacksheep]

That's a YES I take it - Nothing wrong with a one word answer

Thanks, I appreciate the info.

sorry, been reading Bretts posts
yes

[sthughes]

Good call

[Ent]

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[sthughes]

PS (delete who) how does a sheep stay so warm and dry

Well they do get wet but I believe they use a thick wool thermal, an idea they stole from Icebreaker

[norts]

I can atest to the need for DWR, my Macpac Event coat got very wet (only the sleevethankfully) because there was something wrong with the DWR.

Roger

[alliecat]

Kathmandu NGX raincoat - I don't know if it was sweat or more likely water but I was drenched above the waist. It has kept me dry in warmer, wetter conditions in the past but not on this walk. It doesn't bead at all anymore so breathability is non existent in the rain. Will try tumble drying it - that's what Kathmandu suggest.

Umm, if the water doesn't bead on it then the DWR has worn off and the jacket will leak. All the WPB membrane fabrics require a functioning DWR not just for breathability but to be waterproof. I don't know where this idea came from that the DWR is just needed for breathability, but it's simply not true. If the water isn't beading, it's time for a new DWR treatment.

Cheers,
Alliecat

I think you are quite wrong on this point. DWR is just that- a durable water repellent treatment, completely seperate toany lamination or coating which is used. the function of a DWR is critical to allowing moisture vapour to pass through (especially on inefficient "wet" system,s that use PU like Goretex and hydranaut and NGX). if the face fabric is sturated then there is no humidity gradient to drive moisture through. any perception of wet on the inside is simply sweat condensing on this inside of the fabric.

Nope. I know some manufacturers (both garment and fabric) like to say that the DWR is just there for breathability but it just ain't so. I tested this myself a year or so ago. Had a goretex jacket which had not had the DWR replenished for many years. Water did not bead on it at all. Held it under a running tap and after a while the water sort of oozed through to the inner surface. Washed it in a good DWR and repeated the test - not a drop.

I will see if I can find the web site that discussed all this in excruciating detail, but the short answer is: no DWR = not waterproof. That's true for goretex, eVent, Toray entrant, ... all the WPB fabrics as far as I know.

Cheers,
Alliecat

P.S. I don't know that sheep do stay dry - but they certainly stay warm.

[slparker]

I've found this discussion very interesting. I've had goretex jackets and tried Mont's hydranaute and found them all hot and clumsy, albeit waterproof. I bought a jacket on sale at kathmandu this year for xc skiing, it's their ngx fabric but a stretchy version more like a softshell without the fur. It looks like goretex/hydronaute et al but is much softer and more comfortable. Breathes reasonably well as far as Icould tell, but I sweat profusely so usually end up pretty damp anyway. My point is if it's all up to the DWR to maintain waterproofness and breathability then why buy goretex? This stuff I bought is cheap, light, comfortable, breathable and waterproof... My only caveat is that it's probably not robust enough for a walk through scoparia, but what is?
Is goretex really that much better than anything else? Maybe I should ressurect the old japara jacket and give it a coat of DWR instead of grease?

[Ent]

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[blacksheep]

a little code breaking for you (and it is not speculation, but true) the house"brand"NGX=Not GoreteX...