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Windshirt Question
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Woubeir (from Europe)
(Woubeir) - F - MLife
Re: RD Windshell on 02/04/2014 10:44:07 MST Print View

Which Houdini ? The 2013-model or an earlier model ?

Timothy Epp
(Rush2112) - F

Locale: Southwest British Columbia
Re: RD Windshell on 02/04/2014 11:07:43 MST Print View

You could also look at the North Face Verto Jacket. I own that one and it does provide a measure of wind and rain resistance and only weighs 3oz. I got last year's on sale for 75.00

Ryan Smith
(ViolentGreen) - F

Locale: Southeast
Re: RD Windshell on 02/04/2014 11:07:55 MST Print View

"From ample personal experience, the RD Windshell is highly breathable. It's nothing like the pseudo-plastic bag windshirts (ie. Montbell). Unless you're looking for a super DWR windshell to attempt to wear during light rains, the RD is great. Compared to the Houdini, the RD is easily more durable and breathable."

I think Richard tested the air permeability of the Montbell Tachyon and came to a 9 CFM rating. So the RD might be less breathable actually. I might be remembering incorrectly here so take this with a grain of salt.

I am thinking there are many, many factors that will affect how breathable we perceive a garment to be. Maybe that's why the tests and actual experience can differ so wildly on wind shirts and rain jackets. Fit of the garment, exertion levels, actual CFM rating, etc. Dunno. Interesting stuff.

Ryan

eric chan
(bearbreeder) - F
RD on 02/04/2014 11:29:58 MST Print View

the RD windshells of my partners that ive tried and the ones ive played around with at MEC are quite breathable IMO

much more so that my trail wind

as the the MB ... if its the same fabric as the EXL puffies ... well that fabric isnt "breathable" at all ...

as to the "high CFM" thing ... i suspect that most "normal" people these days use their windshells as a semi-static layer or just walking around the park, so a less "breathable" windshell makes sense from a marketing perspective

god forbid you get reviews on backcountry, REI or amazon saying "this $$$$ windbreaker SUCKS, it doesnt block the wind !!!"

and to be quite honest, even among people who use it for higher exertion, most dont think that sweating is such a big deal anyways ... you can always walk into a warm building to dry off

if you want "guaranteed" breathability get a thin non-membrane softshell ... theyll be more durable (and heavier) to boot

;)

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: Montane? Patagonia Nine trails? on 02/04/2014 12:07:48 MST Print View

I haven't seen the Montane windshirts discussed much. They are more difficult to find in the US, but should be included.

I'm a little puzzled by the metric fabric specs: Pertex rates the air permeability of their Quantum GL and Microlight fabrics at 1.0cc max. The conversion calculators I found show 1cc/s = .002 cfm. It seems that I'm missing something terribly, the specs are wrong, or the fabric doesn't breathe much at all.

I got an older Patagonia Nine Trails jacket and have tried it on a few walks. It has a slimmer cut, especially in the arms and no hood. That aside, it has a large breathable back panel and the fabric is the same as the older Houdini from what I can tell. I would assume that the new Nine Trails uses the same less breathable fabric as the newer Houdini, but you still get the ventilation from that back panel. Perhaps this is a work around?

I was surprised to hear that opening a front zipper isn't a gain over 35cfm fabric. I guess that is due to air trapped in around the shoulders and back, particularly with a pack on? I can grasp that my base layer and shell work in concert to move excess moisture away from my skin, but it seems that opening the front zip should make up for a lot of fabric porosity. I'm using a 35cfm garment to start with.

My own technique to managing a windshirt (or rain jacket) is to start opening zippers and cuffs before taking it off. With the windshirt, I might even tuck some of the back fabric up behind my mid back. It's all in adjustment to terrain changes and exertion, forest cover, sun/wind /precipitation changes and additional warmth on rest stops. If I know I will be stopping for a break and I'll be getting the windshirt back out, it seems easier to vent some vs stopping and swapping everything around.

Perhaps a mini wind poncho design would be good for hiking, where you could wear your pack straps under and flip a zippered front panel back over your head and pack when you don't need the extra layer?

Paul Hatfield
(clear_blue_skies) - F
Montbell Tachyon - not actually tested on 02/04/2014 12:21:47 MST Print View

Richard wrote in a different thread: "I have not tested a Montbell Tachyon but, I have tested the SAME APPARENT Montbell 7 denier ballistic rip stop used in their EX Light. It tested 9.72 CFM."

eric chan
(bearbreeder) - F
Re: Re: Montane? Patagonia Nine trails? on 02/04/2014 12:24:04 MST Print View

opening the main zipper makes a huge difference IMO

the problem is that you cant always do that ... it defeats the purpose of a windshirt, which of course is to reduce the chilling effects of the wind

also it doesnt help the arms which, for me, tend to sweat quite a bit

theres no such thing as a free lunch ... for climbing a less "breathable" windshirt can be useful as technical climbing (not easy slogs) are a stop and go activities with belays ... youll feed the wind through very breathable material ... on the other hand with the approach to the climb you may well sweat like a pig if you wear a less breathable windshirt

the way around it i find is to wear very little under the windshirt/softshell (or not wear it at all) when slogging uphill .. and put on a light fleece under (or light synth over it) when doing technical climbing

for hiking one can do something similar with a light fleece vest on descents or flat ground if its chilly

unless you are in constant motion and basically never stopping for more than a few minutes ... its quite hard to find a single layering setup that fits all scenarios ...

runners and cyclist can do it ... but they cant stop for too long or they get cold fast

;)

Edited by bearbreeder on 02/04/2014 12:25:57 MST.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Re: Montane? Patagonia Nine trails? on 02/04/2014 14:04:58 MST Print View

Dale,

Divide their cm3/s/cm2 value by 0.508 for the CFM conversion.

hwc 1954
(wcollings) - M
Strategy on 02/04/2014 15:29:56 MST Print View

My strategy, although I am not always successful in implementing it, is to dress lightly enough to be comfortable on the uphill climb, then immediately throwing on a layer when I hit tree line or the summit exposed to the wind. In the summer, that's often a wind shirt. In the winter, it's probably a lightweight down hoody or a softshell. Then, I will usually leave an extra layer on for the hike back downhill, which is nowhere near the same level of exertion.

I'm realizing that on really cold days (20F and below), I might have to wear an extra layer (like a wind shirt) for the first 15 to 30) minutes while I'm getting warmed up, then stop and take it off for the bulk of the climb. Otherwise, I've got to start out in something that is going to feel very cold at the same time I'm trying to get properly warmed up from an exercise standpoint.

St. Effen
(birdsong) - MLife

Locale: Europe
Re: Re: Windshirt on 02/04/2014 15:49:01 MST Print View

"It's easy to make a calendered SUL fabric which looks good on paper but breathes like crap (Tachyon, Ghost Wisperer, Quantum GL all fit here). Personally, I'm willing to carry 6-7 oz v. 3-4 if I can bust brush and not worry about snags."

+1

The search for a windshirt which ticks all my boxes (decent fit, hooded, full-zip, not too flimsy, <7 oz. (200 g), decent breathability, straightforward DWR renewal, reasonable price) took me quite some time. While the first five criteria were easily met by the Arc'teryx Squamish the last ones were a bit harder to meet.

Yes, I wanted something similar to the Squamish - but made of another fabric (and a bit less expensive). I remembered my favourite shirt in terms of breathability and maintenance: an old 1990 berghaus windsmock made of a polyester microfiber fabric (a tad too burly and color design by a color-blind brit) - no calendering, no coatings, no-fuss. So this would be it - a cheapo Squamish made of Poly.

I found a decent compromise (at least for my needs) and it was a real bargain at 65 Euro (would be around $75 today, not sure if you can find it in the US): Norrona Bitihorn Aero 60 Jacket. OK, not perfect (hood without volume adjustment, shapeless brim, crappy cord locks, fraying edges inside the stowaway pocket), but well worth a look.

Just my $0.02.

Cheers,
Steffen

Ryan Smith
(ViolentGreen) - F

Locale: Southeast
Re: Montbell Tachyon - not actually tested on 02/04/2014 17:10:48 MST Print View

Richard wrote in a different thread: "I have not tested a Montbell Tachyon but, I have tested the SAME APPARENT Montbell 7 denier ballistic rip stop used in their EX Light. It tested 9.72 CFM."

Well, there ya go. Although, I have my doubts that Montbell would develop a completely different 7d nylon fabric with the same lackluster DWR solely for their wind shirts. Never know I guess.

Ryan

Paul Hatfield
(clear_blue_skies) - F
MontBell and Norrona on 02/04/2014 17:22:53 MST Print View

9.72 cfm for the MontBell fabric seems rather unlikely.

The "60" in the Norrona Bitihorn Aero 60 Jacket designation refers to an air permeability of 60 Mbar/l/m²/s. I have no idea what the conversion to cfm is.

Norrona makes two Aero 100 jackets which they rate at 100 Mbar/l/m²/s air permeability. Unfortunately they lack hoods.

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: CFM conversion on 02/04/2014 22:54:26 MST Print View

Richard Nisley replied, "Divide their cm3/s/cm2 value by 0.508 for the CFM conversion."

Pertex lists the permeability of the Quantum GL and Microlight fabrics at 1.0cc, so that is equivalent to 1.968 or basically 2CFM. That is what, 6% of the 35CFM of the older Houdini fabric? That's terrible!

Richard, thanks once again for your patient tutelage here. Your input has really been an education in clothing technology and much appreciated. You really should write a book.

Edited by dwambaugh on 02/04/2014 22:56:34 MST.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: MontBell and Norrona on 02/05/2014 00:15:55 MST Print View

Paul,

The specification for the Norrona Bithorn Aero 60 jackets at 60 mbar/l/m2/s equates to 7.5 CFM. The specifications for the two Aero 100 jackets at 100 Mbar/l/m²/s equates to 12.5 CFM.

St. Effen
(birdsong) - MLife

Locale: Europe
Re: Re: MontBell and Norrona on 02/05/2014 04:22:16 MST Print View

Richard,

I am confused.

Although Norrona does not specify the parameters for their air permeability tests, I suppose they have been testing their jackets according to DIN EN ISO 9237. Hence the pressure difference for testing their apparel should be 100 Pa (compared to 200 Pa for technical fabrics and filter).

So my calculations for the Norrona Bitihorn Aero 60 are:
@ 100 Pa (DIN EN ISO 9237): 60 l/m²s / 5.08 = 60 l/m²s x .197 = 11.81 ft³/ft²min
@ 125 Pa (ASTM D737): 11.81 ft³/ft²min x 1.25 = 14.76 ft³/ft²min

The same calculation yields 24.6 CFM for the Bitihorn Aero 100, which fairly matches my experience with it (soon after the Aero 60 (medium) I also bought the Aero 100 (large) for running, though the Aero 60 is my go-to windshirt as it's generally more to my liking when moving at "normal" speed).

BTW, the Aero 100 fabric seems VERY similar to the pre-2013 Houdini nylon ...

Cheers,
Steffen

Woubeir (from Europe)
(Woubeir) - F - MLife
Re: Re: Re: MontBell and Norrona on 02/05/2014 06:11:11 MST Print View

Well, the question is: do they test according to DIN EN ISO 9237 ? Because if they test according to DIN 53887, Richard is wright.

St. Effen
(birdsong) - MLife

Locale: Europe
CFM conversion: Mr. Nisley's help required! on 02/05/2014 07:35:28 MST Print View

Woubeir,

Not sure ...

It seems to me as if Richard has calculated both CFM values with a conversion factor (x .625) for a DIN EN ISO 9237 test environment @ 200 Pa (the specification for technical fabrics). The factor accounting for a test protocol @ 100 Pa pressure difference (apparel) would be quite different (x 1.25). FWIW, DIN 53887 (predecessor of DIN EN ISO 9237) has been spec'd @ 200 Pa for all kinds of fabrics.

Maybe I just messed up. Hopefully Richard can chime in.

Cheers,
Steffen

Edited by birdsong on 02/05/2014 07:37:20 MST.

Woubeir (from Europe)
(Woubeir) - F - MLife
Re: CFM conversion: Mr. Nisley's help required! on 02/05/2014 09:12:39 MST Print View

For the conversion from DIN EN ISO 9237 to ASTM D 737, I found /4.

Ryan Smith
(ViolentGreen) - F

Locale: Southeast
Re: MontBell and Norrona on 02/05/2014 11:01:38 MST Print View

"9.72 cfm for the MontBell fabric seems rather unlikely."

Not really. That's a pretty poor number which matches most people's reports.

Ryan

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Norrona Spec to CFM Conversion on 02/05/2014 11:15:05 MST Print View

I sent an email to Norrona Customer Service this morning. I will post their response when I get a reply.

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