Richard, count me in as another who devours your posts eagerly. I'm a total newbie and am enjoying your "classes." Please don't anyone else rely in the information I give in an effort to ask my questions.
I understand this graph, but I have a few questions about the calculations needed to create one of my own.
First, in calculating MET (based on the url you gave out earlier), I get a BMR of 1820 for me and 1281 for my wife. I divided by 24 (hours) which gave me 42.1 and 35.6 respectively. If I'm correct, this means that neither of us are as "warm" as the average person. This doesn't surprise me for her (I swear she's a reptile), but I'm always warm, so it makes me suspect that I did something wrong. When I do get the right value, does this just become a linear scaling factor for the graphs you post? In other words, how do I know how much more clo my wife needs than the average person?
Second, I am a little confused at trying to calculate the clo of garments that I own. Since I have some of the same items you do, I should be able to get things to line up better than I do. Here's how I'm calculating clo for an item:
Take the item weight, subtract noninsulating weight, or otherwise calculate the fill weight. Multiply this insulating weight by the clo/oz factor from your other post. Multiply this value by the percentage of the body that is covered by the item. Please let me know if this is wrong.
I do find different numbers from this url http://repositories.cdlib.org/cgi/viewcontent.cgi?article=1046&context=cedr/cbe than I see in your posts for the percentage covered.
body part area m2 %
legs 0.1771 0.120157406
feet 0.0883 0.059909085
thighs 0.33 0.223895787
crotch 0.174 0.118054142
head 0.11 0.074631929
hands 0.0791 0.053667142
arms 0.099 0.067168736
shoulders 0.1514 0.102720673
chest 0.138 0.093629147
back 0.127 0.086165954
Which when I figure a hoodie covers 60% of the head and 40% of the hands gives:
These aren't big differences, but I thought I'd share my calculations.
Third, I recently bought a Nuptse vest for my wife. http://www.altrec.com/shop/detail/13916/
which I'm guessing is around 14 oz of 700 fill down. I see that you have 850 fill listed in your table of clo/oz, but not the lowly 700 fill, and I can't seem to find that information anywhere. Do you have it?
For those that missed it, here's the table I'm using, courtesy of Richard:
Merino wool 0.08
Polartec 100,200, 300 0.16
Polarguard 3D 0.63
Polarguard Delta 0.68
Climashield HL 0.68
Down (550 fill) 0.7
Primaloft Sport 0.74
Climashield Combat 0.79
Climashield XP 0.82
Primaloft One 0.84
Down (850+ fill) 2.53