IDFL test results on downproof fabrics

I made something with fabric that turned out to not be very downproof – still usable but agravating after putting in the time and money to make it.

It would be nice if it weighed more like 0.7 oz/yd2

Understandable. A fabric that light and completely downproof would be great. Though I think as you go lighter you'll be fighting to keep the downproofness up. I know of fabrics around that weight that claim to be completely downproof, but don't exactly live up. Maybe someone has had a different experience, but from what I can tell you have to be willing to trade weight and downproofness to some degree.

Hi Kyle

Interesting, but I wonder whether you have ever asked yourself 'WHY RIPSTOP'? It's a good question.

You see, the large threads in ripstop fabric create holes between them, and this is where ALL ripstop silnylon leaks. Not randomly, but at the intersection of the ripstop threads. Yes, I have lots of photos of this. If you use a fabric which is otherwise identical but without the ripstop threads, you will get a far higher pressure rating for the same weight silnylon, and probably a better degree of down-proofness as well.

In addition, with a ripstop fabric, the wear tenhds to be concentrated on the cross-overs of the ripstop threads. A plain weave fabric actaully gets less wear, and retains its pressure rating longer.

Mind you, my own impression is that the better the down quality, the less leakage there is anyhow. It's the very small feathers which manage to get through the fabric most of the time, not the actual down.

But what about the fabric strength? Well, I have done my own fabric strength tests and as far as silnylon goes, I will stick my neck out and say you get very little benefit (if any) from adding those ripstop threads. Good nylon 6,6 thread is strong enough, especially with a silicone coating!

So why the emphasis on 'ripstop'? It is totally a marketing thing. It sounds technical, so the spin doctors go for it. It seems to have never occurred to them to ask whether there are any advantages to the user. There aren't.

FYI: I have 27 years experience in textile research in a government lab (and a PhD).

Cheers

Roger, that's very interesting. I hadn't considered/realized this before.

I don't have issues with my silnylon leaking enough to cause any issues…would the tiny "pores" you refer to at the intersections of ripstop thread be the source of the condensation issues people report…perhaps it's not that condensation builds up more on silnylon but that more molecules of water leak through the fabric and then combine into droplets over a few hours?

I'm just curious to see if maybe my understanding how silnylon performs on a micro level is misguided.

I've always thought that ripstop fabric was supposed to be better at stopping the spread of rips but not really having a drastic affect on overall tensile strength. Are you saying that this is also possibly wrong and that it's just buzz wording at it's finest?

Thanks,

-Jordan

Kyle is right in that there is typically an inverse relationship between downproofness and weight. We rarely have problems because anyone using .65oz nylon is also using 850-900fp down with almost no feathers. From my experience 1.1oz is fairly easy to make downproof with the stuff used by MYOG'ers.

Ryan

Hi Kyle, nice to see some real testing! Any idea of how you uncalendared 1.1 oz/sqr yrd ripstop would behave with high quality down or synthetic insulatio nthat requires more or less downproof fabric(Primaloft ONE specifically)?

Also you don't happend to have any idea of CFM, MVTR and HH for your uncalendared 1.1 os/sq yrd, calendared and the new taffetta fabric? I'm going to make a series of insulated clothes as well as a quilt or two this fall for winter alpine use and I'm looking for some suitable fabrics.

> would the tiny "pores" you refer to at the intersections of ripstop thread be the
> source of the condensation issues people report.
MOST unlikely imho. Condensation in a tent/tarp is just 'dew': it happens when the fabric gets cold enough that the humidity in the air condenses out.

> I've always thought that ripstop fabric was supposed to be better at stopping the
> spread of rips but not really having a drastic affect on overall tensile strength.
> Are you saying that this is also possibly wrong and that it's just buzz wording at
> it's finest?
Basically, you are correct here about buzz-wording.
It may be that once upon a time fabrics were so weak that they needed reinforcing, but modern nylon 6,6 thread is STRONG. (So is modern polyester.) No reinforcing is needed. All the rest is techno-babble marketing spin. Go read vendor descriptions of joggers or jackets, and see how many pseudo-technical words are used in the product descriptions – and see how many you understand.

Cheers

Rip stop does a good job just that: stopping rips. I generally agree with Roger's points, but rip stop does have its place. Lots of my stuff has had holes torn in, from thorns, stakes, baggage handlers, whatever, and rip stop has often kept the holes from getting bigger long enough to mend them or discard the item.

> rip stop has often kept the holes from getting bigger
For the ripstop threads to really do that well, they have to be much larger than the rest of the threads. In which case there are going to be big holes between the threads, for down to get through uncoated versiopns and for silnylon versions to leak at low pressure.

Cheers

Thanks for all the info Roger. I'm an engineer by trade so I'm always up for a technical discussion. It's interesting that you bring up the topic of ripstop threads and how much value they REALLY bring to a fabric. I say that because I've wondered the same thing, specifically in relation to underquilts for hammocks, but not limited to that single application. When you look at the fabric being used by some of the best cottage vendors making UQs, it's all ripstop nylon. Maybe this is an unfair example, but I guess I can't understand why it would ever matter that you used a ripstop grid fabric for this. Some of the vendors even say that they sourced their fabric with one of the requirements being that it had to have a ripstop grid.

Maybe I'm just naive, but in general I tend to form my own opinions and challenge things that don't make sense to me. If I turn out to be wrong, then so be it. When I set out to develop my first downproof fabrics, I took this approach in being open to using the 1.0 oz nylon taffeta which has no ripstop grid. It also doesn't hurt that the fabric has an amazing, silky hand feel that I loved. Further, my testing at IDFL actually backs up your suggestion that non-ripstop fabrics should have better downproofness. Although it isn't an apples to apples comparison, the 1.0 nylon taffeta actually had a flawless test with 0 particles of down noted compared to the 4 particles for the 1.1 oz ripstop nylon. Probably splitting hairs as they both score at the top of the rating system, but still interesting.

I will say one thing about the marketing aspect of the term "ripstop". I agree with the spirit of your comment, but being a vendor I also understand why other vendors use it. For me, it's a matter of customer perception and using terms that people are familar with, not so much an attempt to put a marketing spin on anything. Basically, if 95% of the customer base is looking for a fabric with the word "ripstop" in front of it, it's probably a good idea to carry at least some of those fabrics and to use that terminology. Totally agree with the point about some never questioning the end value though. Good stuff.

> I will say one thing about the marketing aspect of the term "ripstop".

Our amazing new zero-differential abrasion-resistant invisible ripstop weave leads to a quantum leap in hydrostatic head performance under the harshest field conditions…

Cheers

What, no flux capacitor? LOL. I would call that an oversell.

Hey Edvin. When using synthetic insulation such as Primaloft, I don’t think it’s really necessary to use a downproof or even calendered fabric at all. Maybe it’s preferred, but not an absolute must. Perhaps someone has a different opinion, but I know several folks who have made top quilts using climashield and our uncalendered 1.1 oz fabric without issue.

I’ll work on getting some numbers for those other specs you mentioned.

Where would you find lightweight (non ripstop nylon)? I went to the various DIY suppliers and they sale 1.1 oz ripstop and some offer a 1.9 oz taffeta? I went to the Fabric by the roll site and you mention the 1.0 Taffeta but it was not available unless the site has not been fully updated.

http://www.owfinc.com/fabrics.html

http://thru-hiker.com/materials/coated.php – Shield silnylon is waterproof even though it's ripstop

Although I tend to agree with Roger that ripstop is mostly just marketing spin – doesn't do much good, it also doesn't do much bad. Like the Shield

I feel like I am in the dark ages while reading this.
We're talking pre-M90 days.

Most DIY use 800+ fill.

You have :
M50
Argon
Nobul2
Pertex GL

They all do a very good job at being downproff.
Not only are they up to 45% lighter, they do a good enough job to have made 1.1 fabric obsolete for the past 10 years.
Why would I add 3 ounces of fabric weight to my quilt, other than to save some money?

Testing downproffness is easy. You put down in it and see if it leaks.
I don't care about a 1-5 number if it doesn't leak. I want it to be light.

I think down proofness test is more difficult.

I made quilt with Nobul1. Just putting down in it and manipulating it it doesn't leak. But after sleeping for a night there's quite a bit of leakage.

And, I would rather buy some fabric that is known good. I don't want to buy some, then find out it leaks, even if I haven't made something out of it yet.

> I don't want to buy some, then find out it leaks,
ALL fabric leaks the small feathers. Just at different rates.

Cheers

Hey Scott. The 1.0 Taffeta isn't on the site quite yet. Should get it listed today though.

Thanks for your comments Aaron. You are completely right in pointing out the existence of much lighter downproof fabric options. However, not everyone is willing/able to put up the extra cash to get those branded, lighter fabrics. Outside of the cost difference, I would contend that not all the fabrics in that list have great downproofness. I'm sure all of them claim to be "completely downproof", but personally I would rather see hard data as opposed to just accepting statements made by the vendor. Same goes for the home testing. I think it's fine to do initial home tests to assess the worth of a fabric, but in the end I want to take myself out of the equation. I guess it's just my opinion that there's a lot of value in running the fabric through a standardized, lab test and presenting the results. No subjectivity, no variables, here's what you get. If we're talking about marketing spin, I don't see any better way to take that out of the equation than standardized testing.

All in all, my goal with these 1.1/1.0 varieties was to make a reasonably lightweight fabric with excellent, proven downproofness that's also affordable. Lighter weight options are on the radar for future development though.

> there's a lot of value in running the fabric through a standardized, lab test and
> presenting the results.
I totally agree!
But is there a lab test for 'down-proofness'?

Cheers

Ha. That is the name of the test, but to pivot off your earlier statement, the test is really a measure of the rate at which down leaks out of a given fabric. No fabric will be 100% "downproof". To be specific, the test measures the number of particles of down that come out of a test pillow, mock-up panel, or finished product in a specified time period. The fabric then gets a 1-5 rating based on the # of particles.

Hi Kyle

> the test measures the number of particles of down that come out of a test pillow,
> mock-up panel, or finished product in a specified time period.
Tell me more please?
Like does the pillow just sit there, or is there forced air flow, or do you indulge in a pillow fight, or what?
A copy of the Test Definition would be great.

Cheers

This .pdf appears to give a little insight into their testing methods:

http://www.idfl.com/media/pdfs/news/IDFL%20News%2055.pdf

And the test submittal form lists some of the tests:

http://www.idfl.com/media/pdfs/IDFL%20Submittal%20Form%20-%20DOWNPROOF%20A4.pdf

EN 12132-1 (Rubbing)
EN 12132-2 (Impact)
GB 12705.1-2009 (Rubbing)
GB 12705.2-2009 (Rotating Box)
GB 14272-2011 (Rubbing – Outerwear)