By the Numbers: the Search for a High-MVTR Waterproof Breathable Shell Jacket

[Stephen Seeber]

Hi Nicholas: I have only tested Dermizax DT.  It had good hydrostatic head performance but MVTR was pretty low at 1560 g/mw/24/hr.  The Stellar website lists MVTR at 20200.  They don’t list the standard used.  I assume it is JIS L1099 B1.  For that standard, 20200 is pretty low.  It will definately need pit zips, which are not included.  If you ever want to part with your NX jacket, I would like to measure its performance.  PM me if you want it tested.

[Nicholas P]

Thanks Stephen,

I’d be interested in having you test it but I wouldn’t be able to part with it until the end of the Ski season here in the northeast.

[Stephen Seeber]

Hi Nicholas: I will be around.  Stellar does sell NX shells.  It provides a rating of 25000 g/meter2/24 hr.  That is about 1711 in my system. It will be interesting to see.  Send me a PM when you are ready.  Enjoy your skiing.  Here in Colorado, on the Front Range, I am still waiting for enough snow to make it worthwhile.

[Bert Blanchard]

Fantastic article and always interesting replies!  I just tried to find any of the jackets listed in Stephen’s “above 3000 MVTR” list; but it seems that they are all being discontinued. Perhaps due the the DWR treatment containing banned substances? Or is there some other reason (updated version by manufacturer)?  It is hard to keep up with the manufacturer’s changes every year.

[Bill Budney]

ShakeDry is being discontinued. AscentShell and PreCip continue.

[Stephen Seeber]

Thank you Bert.  If you are looking for a WPB Membrane, electrospun fabrics such as Neoshell and Ascentshell, as well as other choices from a couple other manufacturers (Scholler and Pertex) are probably the best bet.  Ultimately, the performance of electrospun membranes (and all others) depends largely on the face fabric performance.  You want the lightest face fabric you can find to get maximum vapor transfer.  A reader is sending me a couple fabrics to test that may prove useful.  I will post something if I learn anything useful.  Of course, just because a MYOG member can purchase fabrics does not mean there is a manufacturer making a suitable jacket with that fabric.  You may have to learn to sew.

[Jerry Adams]

Per your suggestion I made a jacket from neoshell

The best thing about that is the DWR is really good.  Probably the stuff they’re going to quit making.

Best rain jacket material I’ve used

[HkNewman]

> Neoshell

An update brings up the waterproofness wasn’t good for marketing, while Gore and others copied the idea.  That makes Neoshell more expensive and marketing towards a small # of enthusiasts.

The plus is the fabric is still very breathable while maintaining excellent water repellency. The shells below are fairly heavy for what they are but could see it for exerting in winter.

Dated: 4 Jan 2024

https://nailthetrail.com/best-polartec-neoshell-jackets/

Most of the jackets look more for the slopes vs the trail, though a backpacker with a heavy load may want that Westcomb.

Wonder if an Neoshell anorak with maybe a partial (1/3) chest zip would be a lighter design?

 

 

[Scott Emmens]

Interesting article about Neoshell.

Not sure I agree with their assertion that “However, no so-called waterproof/breathable fabric is completely waterproof”, this is simply not true, most WPB fabrics are waterproof, often the garments they make aren’t but it is pretty rear for a quality fabric (when new) to not be waterproof. Neoshell’s waterproof rating (hydrostatic head) was/is lower than similar fabrics but they still reach the threshold of being “waterproof”. The issue is how long they remain waterproof after use, now that’s a different story. But to blankly say that no waterproof/breathable fabric is waterproof is simply wrong.

Cheers, Scott

[Bill Budney]

Yes. I have experienced condensation under several WPB jackets; sometimes enough to make my base layer feel slightly damp. It is not a leak; it’s just weather occurring inside the jacket. The jacket itself is waterproof.

[Scott Emmens]

However both PreCip and AscentShell are the apparel brands own marketing fabric names – often for a series of fabrics or garments – this marketing name often remains unchanged, even when fabric specifications change – including fabric supplier. A brand I once worked for used (still uses) a fabric called NGX, which was simply an acronym (not strictly) of “Not Gore Tex”. This fabric has changed untold times over the years, the supplier, the quality, the construction, everything about it, yet it is still called NGX!

Even knowing the fabric suppliers own name of a particular fabric doesn’t always help as they are often the name for a series of fabrics, or even just the membrane used, for example Pertex Shield. There are numerous versions of this fabric, I have a copy of a test report of  28 versions of Shield fabrics that have results in Water Vapour Permeability ranging from 19344 through to 78264 g/m2 24hr – ALL using the same membrane, all called Pertex Shield! Most big brand have fabric “built” to their own specifications depending on what the particular features are they require for that item i.e. durability vs lightweight.

The thing that I believe is the biggest factor affecting real world use of these garments is the DWR – or rather lack of “durable” in DWR’s! That’s where Shakedry really shone.

OK enough from me ;-)

Cheers, Scott in NZ

[Jerry Adams]

I made a jacket from RSBTR WPB fabric.  It’s lighter and cheaper (1.4 oz/yd2, $21/yd) than neoshell (5oz/yd2, $45/yd). From Discovery Fabrics.

The RSBTR wets out and then gets wet from condensation when it rains a lot.  Fine in light or no rain

The neoshell is much better

Just from observation, it’s not the water vapor permiability, but the DWR coating.  I have not seem any measurements of DWR so it’s hard to compare.

The DWR may degrade over time, I haven’t used it too many times.

I will use the neoshell if rain is predicted.  The RSBTR better on longer trips when I want to minimize weight.

I’ve made jackets with other fabrics and they’ve been more like the RSBTR, except the RSBTR is lighter

 

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