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Peter Clinch · 22-01-2013, 08:12 PM posted to uk.rec.walking,uk.rec.gardening,uk.d-i-y

On 22/01/2013 18:03, wrote:

Physics is not mocked. What I said is correct. You may well
believe in Maxwell's demon, but there's no such animal.

Once Goretex gets saturated, the surface tension no longer blocks
water from passing through, and it is no longer waterproof.

Gore have a ridiculous guarantee, "guaranteed to keep you dry". A
classic case of the large print giveth and the small print taketh away,
but in this case the small print points out the foundation to the claim
is a hydrostatic head well in excess of that considered to be
"waterproof" (MOD say 800mm, outdoor industry reckon 1m).

And that is hydrostatic head, which will be maintained whether or not it
is "saturated". XCR has a measured HH in excess of 4m IIRC, so (a) it's
difficult to see how you can apply that in testing without "saturation"
and (b) percolation rate would be zero /or Gore would be sued left,
right and centre over their fraudulent guarantee/.

Once Goretex gets covered with water on the outside, saturated in
any other way, or it gets colder than the dewpoint of the water
vapour inside, it ceases to be breathable.

That certainly does appear to be the case. Same goes for pretty much
any other waterproof/breathable fabric, of course.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/