Originally Posted by Jarery
4) You mentioned that nothing breathed well as the difference in humidity levels approached the same across both layers. Again, did you even look at the links? Appears you didnt. If you had you would have seen that Gore like many others is dependant on the relative humidity, but that there are several materials that are not dependant on it. In other words, they continue to transport moisture across the layer even in times when the humidity is similar, as in sweating when its raining.
It was me made the claim that breathability was NOT RELEVANT as the outside humidity reached 100%, as it would in a steady rain, and I based my statement on both my experience and the documents you linked to, which I first read over a year ago.
The document you provided shows the while goretex lags behind some of the other fabrics in vapour transport, it improves at higher humidities, but stays lower than some of the newer fabrics. But none of them are beneficial in a steady rain, as I have never heard of any fabric that can PREFERENTIALLY move water vapour OUTWARDS, and I know of no basis for this in physics without some type of active system. Hence, the vapour flux shown on those graphs means that although water vapour can freely pass back and forth, the inside won't end up DRIER than the outside, and if it's raining, you sweat won't evaporate.
Again, I have some reservations about the performance of goretex for the pricepoint and I am curious about some of these alternatives. But lets not overdo the goretex hatin'.