I found this video which tests the breath-ability of various jackets.

You Tube Video

Given that 02 molecules are slightly larger than H20 is it a valid test?

As said in the first vid, the best test is to go run up a mountain. Good luck finding a shop that will let you do that!

It’s based on an old eVent promotional tool which yes, shows exactly that. The reality though is what matters is how fabrics work when you use them in real world conditions, which doesn’t always correspond to lab simulations.

It’s not like your body is pumping out air at high pressure for example, which is what this simulation is really testing. I’m not saying it has no relevance to moisture vapour transfer rates btw, but it’s a bit like assessing a tyre rubber compound simply by jabbing your thumb into it.

It tells you something, but not necessarily how it’ll work on the trail.

https://www.youtube.com/watch?v=BD-aAFaWerk

Thanks for sharing that.

I would like to see a test that involves humidity test and which fabrics offer the best transfer rate through them.

The fact that Gore boxes were stacked high across the back of the video did raise the question “is this an independent test?”

“is this an independent test?”

Of course they weren’t. But they do explain why the air bubbles aren’t a great test.

I would like to see a test that involves humidity test and which fabrics offer the best transfer rate through them.

There are various lab tests that purport to do that based on hot-plates and steam. They don’t necessarily relate to the real world either. I’ve seen a Gore-Tex Active launch presentation which showed, based on tests, that Gore-Tex Active is ‘more breathable’ than a cotton tee-shirt. Go figure…

Polartec (Neoshell) uses a different test which it says is more closely aligned to real world use, but what really matters is how it actually works. Brands tend to pick the test which reflects more favourably on their chosen technology.

As an example, the new weirdd-looking, rubbery, Gore-Tex Active fabric without a face fabric is properly real world impressive, partly because it never wets out, so the performance is consistent even after several hours of use. Conventional fabrics always end up with a saturated outer layer, which significantly limits breathability after an hour or so.

Paramo stuff which works impressively ime in damp, cold conditions isn’t technically even waterproof in the lab, but works really well in real life as long as it’s cold outside. NeoShell is the most breathable conventional waterproof fabric I’ve used, but not as outright and consistently durably waterproof as, say, Gore-Tex Pro. Not a problem short term, but potentially one with extended use.

So yes, but…

You could look up how your fabric performs in an ISO 11092 test.

http://www.iso.org/iso/catalogue_detail.htm?csnumber=65962