I recently went on a trip to the desert, and got caught in rain. It was not really torrential rain, but it was steady light rain for 8 hours or so. It was fairly chilly, maybe 40-50 degrees outside and I was barely sweating. I threw on my Outdoor Research Helium II jacket (made of Pertex Shield+) and some custom Pertex Shield rain pants with taped seams made by a prominent vendor. The rain pants had only been worn once before and were essentially new. Last time I used them, there was essentially no abrasion.
Much to my surprise, the rain pants wetted out in about 30-45 minutes. My entire legs were soaked. My upper body was nearly completely dry. I changed into my regular hiking pants and they too wetted out in about 30-45 minutes as expected since they are not waterproof at all. I was cold. The rain pants essentially provided no waterproofness.
Any thoughts? I thought Pertex Shield was supposed to be very waterproof. I realize that all materials will wet out after prolonged sustained rain when you sweat, but I was not sweating and 30 minutes seems very fast. It's supposed to have 10,000mm waterproof rating.
