I see floor mats rated with R value and I can't understand why it isn't the same for sleeping bags and quilts.
Anyone know why they don't use the same rating for everything that keeps you warm?
I see floor mats rated with R value and I can't understand why it isn't the same for sleeping bags and quilts.
Anyone know why they don't use the same rating for everything that keeps you warm?
Good question. I think the problem is that consumers think about bag ratings in terms of "how warm will be in this bag," or "how cold can I go" instead of "how thermally insulative is this bag?" I believe it is because the unknown variable is the occupant. Trying to standardize the warmth rating is challenging. The r-value doesn't tell you how warm it is, but a measure of heat resistance.
A sheet of plastic or tyvek may have hi r-values, but wrapping yourself in them may not give you the same warmth as a sleeping bag. There are a lot of factors in play.
Author and illustrator: The Ultimate Hang: An Illustrated Guide To Hammock Camping
The bottom half of a sb is compressed, reducing the insulative value of that portion of the bag by a considerable amount. Thus, the r-value of a bag varies with what's under it, effectively making it a system value. The maker of the sb has no control over that.
Dave
"Loneliness is the poverty of self; solitude is the richness of self."~~~May Sarton
R- value was set up for construction. that's why pads and things with air gaps have R-values (they were being used in construction before we started using them.)
R-value is determined under consistent standards. our bodily internal heaters are not consistent. even if a quilt was rated at R-5 the first question would be, but how cold can i go. then we would need a chart. we could put it with all the abbreviations i don't get yet.
most people don't even know that cold is the absence of heat and a quilt is retaining heat not keeping out cold. tell some body that their house AC is removing heat, not adding cold and look at the blank stare you get.
KK&K
"Tenting is equivalent to a bum crawling into a cardboard box, hammocking is an art" KK
Oh how true that is!
Thanks for the answers everyone. I just found out something else about sleeping bag ratings here: http://www.mec.ca/Main/content_text....34374302887297
To me, that is the advantage of going with something standard like an R-value. It will be pretty easy for me to deterimine what temperature R-5 relates to for me, which will likely be different for others.
Having a bag/quilt manufacturerer choosing a temperature rating is completely subjective and doesn't really provide me any means of comparing them objectively.
I would love to see all bags/quilts showing a standard R-value.
We must, indeed, all hang together, or assuredly we shall all hang separately. - Ben Franklin
(known as a win-win on this forum)
I completely agree with everybody! =)
To put a finer point on what I think Alamosa is getting at, an industry standard test, that shows an insulation rating regardless of how an item is used. Like an R-value, would be a nice addition to all specification sheets.
I ride a recumbent.
I like to HAM it up on the CW.
I use Linux.
I play go.
Of course I sleep in a hammock!
Rug.
Hang On!
before that they were using tog values
Lightweight summer duvet: 4.5 tog
Spring/Autumn weight duvet: 9.0 - 10.5 tog
Winter weight duvet: 12.0 - 13.5 tog
we can't use R-value because it is for things stationary (buildings) even if we came up with another value wouldn't it still be subjective for the manufacturer to determine it? if we had things tested by testing companies who would pay for it? in the end i think we would.
"Tenting is equivalent to a bum crawling into a cardboard box, hammocking is an art" KK
my thoughts are that when you have household items, like insulation, it IS standardized, unlike quilts which all have different variables including fill type, baffles, materials etc...
same with pads. ccf pads get compressed, causing variations in insulative qualities, and with air pads, each user may end up inflating it to different PSI's and therefore causing the same variables with weight and otherwise.
so whereas home stuff is consistently used the same, things WE use constantly changes.
Give a man fire and he's warm for the night.
Set a man on fire and he's warm for the rest of his life. Dante
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