Feb 18, 2014 at 11:09 am #1313466
Comparing an eVent bivy to a Water Resistant bivy like the MLD Superlight, what's the breathability rating discrepancy?
In other words, how much more/less breathable is eVent? Anyone happen to know?
-MaxFeb 18, 2014 at 4:46 pm #2074852
Event (waterproof) may be 21,000 gr/m2/day (found in another post on BPL)
Gore-Tex PacLite about 15,000+ gr/m2/day (taken from wikipedia)
Silnylon (waterproof) bottom of bivy is not breathable
Momentum (water resistant) top may be 25,000+ gr/m2/dayFeb 18, 2014 at 4:49 pm #2074854
Yeah, the breathability ratings were definitely what I was looking for. Thanks!Feb 18, 2014 at 5:53 pm #2074881
Could you edit/add a line for Gore-Tex Paclite? (Or whatever is the latest and greatest from Gore?)
Thanks.Feb 18, 2014 at 7:01 pm #2074902
Found a rating on wikipedia Greg. I don't know how reliable all of those numbers are though.Feb 18, 2014 at 7:11 pm #2074905
I found another resource that had this to say:
That being said, I defer to BPL testing because this chart seems suspect (Gore-Tex 2 and 3 layer are identical? hmm…) and I thought someone had the scoop; I am excited to hear other opinions or even anecdotal reports too.Feb 18, 2014 at 8:07 pm #2074931
This chart from Natick is now 15 years old –
The full PDF is buried somewhere in Verber's Website
Is there anything more recent?Feb 18, 2014 at 8:30 pm #2074941
Too bad that chart doesn't have eVent… not to mention, the state of the market in the late 90's was surely different.
Edit: I see it now, thanks Dave!Feb 18, 2014 at 8:41 pm #2074945
"Too bad that chart doesn't have eVent… not to mention, the state of the market in the late 90's was surely different."
Sure it does.Feb 18, 2014 at 11:34 pm #2074979
the chart may be dated but it is still usefull. It can also be confusing. In this chart the beast breathable fabrics are on the bottom not on the top like most people are use to seeing.
On this chart zero on the vertical axis is the most breathable. 100 is the worst. The x axis is the humidity on both sides of the fabric. most of the fabrics on the chart are a slanted line. Which means these fabrics have very poor breathability at 30% humidity. The breathability then increase as the humidity climes. Most of these fabrics use polyurethane membranes.
"Too bad that chart doesn't have eVent…"
Most people would expect the best fabric near the top. For this chart you need to look at the bottom. there you will find Event, Expanded PTFE, and Entrant.
Expanded PTFE is the original version of Gortex. they stopped making it after it was found that body oils would clog the membrane preventing it from breathing. most Gortex today has the expanded PTFE membrane with a very thin Polyurethane membrane on it. The PTFE is now a support structure for a very thin, fragile, and very breathable polyurethane membrane.
Entrant was a microporous polyurethane membrane that looked really promising when I saw it on a chart like this a couple of years ago. However I quickly found nothing on the market made from it. Apparently it was pulled from the market. I don't know why. Toray industries than apparently introduced a series of polyurethane fabric but none appeared as breathable as Entrant or today's Event. I also looked at many of the others on the chart and most didn't impress me.
Event is a expanded PTFE membrane that has been treated so that body oils don't stick to it. I don't know how they did it but it did Solve the original problem Gortex had.
Today we can add Polartec Neoshell near Event on the bottom and apparently a vastly improved gortex pro shell. and maybe a few others scattered on the chart. However one thing remains the same. Most mono-film polyurethane breathable jackets do not breath nearly as well as event. But due to the light weight and low cost polyurethane remains popular.Feb 19, 2014 at 5:30 am #2075019
>> Event is a expanded PTFE membrane that has been treated so that body oils don't stick to it. I don't know how they did it but it did Solve the original problem Gortex had.
I believe the original problem GoreTex had was not the ePTFE getting contaminated so it was clogged, but that the ePTFE membrane started disintegrating. How do eVent jackets hold up in the field? Are they sold in large enough numbers to know if the membrane is durable?
Marketing mumbo-jumbo aside, it appears that eVent has a DWR treatment applied to the ePTFE membrane. How long does the DWR treatment last?Feb 19, 2014 at 5:49 am #2075023
It really was contamination.
And the DWR isn't any different or any different applied then in any other WPB-fabric.Feb 19, 2014 at 7:22 am #2075042
Yes. It was contamination, but as I understand it, the subsequent leakage was because the ePTFE membrane started to disintegrate. Do we know that this does not occur with eVent?
There are so few eVent jackets sold that it is hard to find large numbers of reviews. From that small sample, there are a lot of waterproofing failures reported along with admonitions that eVent has to be washed more frequently to keep it waterproof. Is it relying exclusively on the DWR for water resistance, as is the unprotected ePTFE membrane in Gore Windstopper?Feb 19, 2014 at 7:43 am #2075046
I have 2.5 layer eVent jacket. After a couple years (100 nights) it became discolored at shoulders and back of neck on hood. DWR quit working. I washed it and applied DWR and it seems much better, but I assume it's not good so I use something else now.
I think the 2.5 layer is especially bad. Body oils and dirt affect the membrane. Three layer (a seperate layer of fabric inside) might be better, but then its heavier.
They say DWR is required to make membrane work. So why not just have a DWR and forget the membrane?
I made M50 jacket and it seems pretty waterproof. Or M90 would work. I think maybe I'll get more sweaty though, not as breathable as eVent? I do get sweaty on back of neck and shoulders if I have hood up. Maybe the eVent was better. Maybe if it's really raining and I'm exercising then there is no way to stay dry with any material? I like the 5.5 ounces for a long jacket with pockets.Feb 19, 2014 at 8:57 am #2075065
It is not easy to get real disintegration of PTFE or ePTFE. So all those leakage reports might be a quality issue during production.
The leakage for original GTX (now Windstopper) was a consequence of contamination of the ePTFE-membrane, making it loose its hydrophobic properties, resulting in leakage. That's the main reason for including the PU-layer. eVent eliminates that by coating the interior of the ePTFE-layer with an oil/dirt-hating coating. Ih principle, 2,5- or 3-layer construction doesn't matter for waterproofness, but does for durability.
The DWR-treatment is a completely other point. While the ePTFE-layer in itself is extremely hydropopbobic, it is also very fragile, meaning it has to be covered by an outer protection layer (typically a nylon or polyester fabric). That 'protection layer' is only slightly hydrophobic and thus needs a DWR-treatment. The DWR only makes the fabric repel water (for a too short time; making a truly durable DWR was, is and will be the challenge), and certainly not waterproof. And it is thus not the extremely hydropopbobic that's covered by the DWR, but the 'protection layer'.Feb 19, 2014 at 9:28 am #2075082
But Richard just said the M90 has 950 mmH2O, need 1500 mmH2O to be rainproof, maybe 950 is good enough.
When I take M50 and puddle water on the top of it 1/4 inch deep, for several days, there is no leakage. I've had M50 sleeping bag get wet from dew and the down inside absorbed no water.
Experienced people say that if it rains enough and you're exercising, eventually you'll get wet, even with best membranes
Maybe DWR is sufficient.Feb 19, 2014 at 9:35 am #2075090
I have no personal experience with eVent, but I recently came across the following thread on the UKClimbing website: http://www.ukclimbing.com/forums/t.php?t=578102.
I considered starting a new thread for it, but I think it fits here.Feb 19, 2014 at 10:35 am #2075116
"But Richard just said the M90 has 950 mmH2O, need 1500 mmH2O to be rainproof, maybe 950 is good enough.
When I take M50 and puddle water on the top of it 1/4 inch deep, for several days, there is no leakage. I've had M50 sleeping bag get wet from dew and the down inside absorbed no water."
True, but those are results from a static test. For real world conditions, you have to factor in dynamic conditions and aging. And I've once read a test wherin some fabrics had an initial HH of more then 5000 mm and after only 6 months UV-exposure it dropped to less then 1500 mm.
"Experienced people say that if it rains enough and you're exercising, eventually you'll get wet, even with best membranes"
Sure, I can even get wet if exercising intensely while wearing nothing. So you can then get everything wet.
"Maybe DWR is sufficient."
Well, sometimes I prefer my only water repellant windshell in rain (even if it's heavy), but as often (or even more) I'm glad to have a waterproof shell.Feb 19, 2014 at 12:53 pm #2075142
well said Woubeir
I'll continue using my M50 jacket and see how it does over time and conditions
I have an Epic jacket that seemed waterproof (although I'm not sure now) and then all of a sudden I noticed it provided almost no protection. I have to try cleaning and re-applying DWR
If I had to wash and re-apply DWR once a year that might be reasonableFeb 19, 2014 at 1:42 pm #2075169
>> The DWR-treatment is a completely other point.
Not really. If you read the GE eVent patent, the material they are using to coat all the internal nodes of the ePTFE membrane is — drum roll — the material that is widely used for making DWR treatments applied to fabric. eVent's patent is for the process of applying a DWR solution to an ePTFE membrane.
Hence my question: How long does this DWR applied to the ePTFE membrane last in the real world? If it were to break down (as DWR treatments on fabric do), then eVent becomes an unprotected ePFTE membrane (i.e. Gore-Tex Generation 1 or Gore-Tex Windstopper).
I don't know the answer. I'm not saying that eVent membranes don't last forever. Just saying… the instructions to wash frequently to preserve the water repellency raise a red flag to me.Feb 19, 2014 at 2:03 pm #2075175
True but still there is a difference: with the BHA-membrane the interior is coated while the classic way is on top of a fabric where it is exposed to outside influences and thus is far more easily overwhelmed and/or abraded (and not broken down as you suggest).
The instructions to wash frequently is because of the exterior DWR and not the interior one.Feb 19, 2014 at 3:58 pm #2075209Feb 19, 2014 at 4:10 pm #2075213
>> The instructions to wash frequently is because of the exterior DWR and not the interior one.
I mean, sure, washing/heating/restoring the DWR treatment is a good thing for all jackets. But, why does eVent seem to make SUCH a big deal of it. I mean, there were no admonitions with my Gore-Tex ProShell jacket that I had to wash it frequently or it would not longer be waterproof.
It just raises a red flag in my mind. Is there something about eVent that makes it particularly prone to leaking if the outer fabric wets out? Theoretically, a membrane jacket should still be waterproof, no matter what. If I have to rely on the DWR to keep water out, I might as well wear my Houdini…Feb 19, 2014 at 11:45 pm #2075339
"I have no personal experience with Event, but I recently came across the following thread on the UKClimbing website: http://www.ukclimbing.com/forums/t.php?t=578102. "
I have seen similar post including a video. In the video the 6 month old Event jacket completely wetted out in what appeared to be a moderate rain. My 20 year old Gortex jacket never wetted out like his did. It was also wetting out in areas that don't get a lot of friction or abrasion In the video he also said every breathable jacket he has tried did this
I suspect that somehow people are contaminating the fabric without knowing it. If you look at the Event care instructions they say not to use fabric softeners. i recently remembered a news article about fabric softeners. Fabric softeners contain oils that stay on the fabric. This reduces static problems and makes the fabric feel softer.
In the news article the washer had a smell problems. The machine looked fine but when the machine was disassembled there was a thick coating a fabric softer residue everywhere. In some places it had to be removed with a putty knife. I have also seen post about this online.
So if your machine has a heavy coating in the places you cannot see washing a event jacket in the machine may be a bad idea. the softener in the machine may come off and coat the event jacket even if you didn't put fabric softener in with the event jacket.
Also in your link you will see people posting that they have washed and reapplied DWR frequently and it still doesn't hold up. Perhaps it is possible to over apply DWr and or overwash the garment?
Anyway if you are having issues with wetting out and washing and applying DWR aren't working try the dry cleaners. I never use fabric softener in my machine and the DWR seems to hold up well.Feb 20, 2014 at 2:07 am #2075346
The difference according to me is that eVent is really microporous and most are not. Added by the fact that the ePTFE-layer in itself isn't oleophobic, but needs an added coating that is oleophobic (but by that way also more vunerable). The fact that there were no problems with your GTX Pro Shell, may only be because Gore is in the business for much, much longer. They had similar problems the first decade or so, but managed to solve it. In fact, BHA is/was probably aware of that and after the first patent followed another.
But I admit that writing that the washing instructions were only meant for the exterior and not the interior, was incorrect. Even with the oleophobic coating, oils and other kinds of dirt can penetrate the BHA-membrane. But here starts the difference according to me. With GTX Gen. 1 there was no oleophobic coating so the bonding between the contaminants and the membrane was pretty strong. With the BHA-membrane there's still contamination possible, but the bonding is less strong. So, while washing a GTX Gen. 1 garment might not have given the desired result (100 % waterproof), chances with the BHA-membrane are much higher.
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