Originally Posted by
erig007
Have you watched a video of a body sweating? A body produces steam. How much will depend on humidity and temperature though.
Esk = Ws (psk - pa) / (Recl + 1/(fcl x he))
Esk: evaporative heat exchange
Ws: skin wettedness factor
psk: water vapour pressures on the skin surface
pa: water vapour pressures in the air
Recl: clothing intrinsic evaporative resistance
fcl: clothing area factor
he: evaporative heat transfer coefficient
Hmm, here I thought experiencing sweat first-hand would qualify me for knowing how I sweat better than doing a youtube search. Live and learn, I suppose...
But then you've got that "Ws skin wettedness factor" in your equation. If sweat comes out of the body as steam, it would have to condense on the skin to produce that wet stuff I've been calling sweat for the past several decades. Wouldn't that imply sweat heats the body up due to the latent heat of vaporization (which seems to be missing from your equation)?
Not to mention that the entire equation only makes sense if not all the sweat escapes as vapor.
Bottom line seems to be vapor-permeable fabrics work best in cool and/or dry air, and they work best when the body's not producing much sweat.