Climasheild ratings

[Troy Ammons]

Noticed Tim Marshalls site list CS ratings as 2.1 = 50df, 4.0 = 40df, 6.0 = 30df etc.

Back a few years I remember basically that 2.5 = 45df, 3.6 = 35df, 5.0 = 25df and I always felt that was was optimistic.

I know its highly subjective and depends on how you sleep, but just curious.

[And E]

Definitely subjective.

I was plenty comfortable in my 5.0 apex quilt down to freezing with just base layers+grid fleece. I was almost too warm in my 2.5 apex quilt when it was low 40's wearing just light weight top, underwear, and windshirt (I forgot to bring a beanie).

My body runs warm, and I share a tent with my wife who is a very cold bodied person.

[Jeffrey Wong]

Right on. The ratings verge on overly optimistic for cold sleepers. Friday night we hammock camped about 100' from Goat Creek (Goat Rocks Wilderness)–ya, ya, we should have walked another 100 yards away from the creek, but we hadn't focused on that. My 58" x 48" underquilt with Apex 6.0 had me "awake" most of the night envious of my hiking buddy, who I assumed was warm. We guessed overnight temperatures dropped to 39* (at worst) due to lack of frost in the morning.

[And E]

Crazy! My wife and I camped at Goat Lake Saturday night! The super moon was crazy bright. The lake was still almost completely frozen except for a kiddy pool sized spot. A guy who was visiting from Colombia jumped right in for a quick shower/cool down. Nice guy, must've been refreshing. I wasn't brave enough to join him.

[Jeffrey Wong]

And on such a gorgeous day! If we were there at the same time, you might have noticed the odd couple. Ben wore a hat, long sleeves, long pants. I wore yellow running shorts, silver t-shirt, dirty yellow trail shoes, a lumpy brown/white RayWay backpack and eau de permethrin. We walked through Snowgrass Flat on Saturday, arriving at Goat Lake about noon. We ate lunch just below the lake along the outflow tract and left about 1 p.m. We then climbed the trail away from the lake, crossed the Goat Ridge, filling our bottles in Jordan Creek, & continued along Goat Ridge, until we found some trees from which to hang our hammocks just past the northernmost trail junction of 95 and 95A.

We met the guy (his first time backpacking) from Colombia at the Lily Basin Trail junction, with his friends from Seattle, one a charming Latina. Sunday a.m. a slim guy from Portland via Nepal came down from Goat Lake, completely jazzed up about camping the lake–surely you met him, too?

[And E]

We had a late start on Saturday, I think we started around 1:30, from the Berry Patch Trailhead going clockwise, doing the snow grass – cispus basin – Nannie ridge loop and hitting the PCT detour on the way out. We both were using the packs I made, and my wife's bright orange pack is pretty hard to miss. I didn't meet any Nepalese guy though. It was quite the busy/popular hike! When we came out from the snow grass flats trail head on Sunday, the trailhead was packed full of cars, while Berry Patch only had about a dozen or so cars.

P.S. SORRY ABOUT THE THREAD HIGHJACK!

[Jerry Adams]

I can see why vendors are optimistic about ratings. If a vendor advertises same sleeping bag at a lower temperature rating, people will tend to buy it instead of the higher rated exact same bag at a different vendor.

And if a vendor is realistic, they will lose sales.

According to Mammut document http://www.mammut.ch/images/Mammut_Sleep_well_pt1_E.pdf

2.6 clo is good for 17 C = 62 F – assumes you wear just base layer inside bag – lower comfort limit for men. Skin temperature is 92 F, so 30 F temperature difference for 2.6 clo

Climashield is speced at 0.82 clo/oz/yd2, so 4 oz climashield is 3.28 clo. This would produce a 38 degree F temperature difference. subtract from 92 F = 54 F temperature rating

So, if you apply the EN13537 assumptions and use the lower comfort limit, then 4 oz Climashield should have a 54 F temperature rating if you wore just a base layer inside.

If you wore a 1.2 clo garment inside the 4 oz Climashield quilt, that would give you an additional 14 F temperature difference. A 1.5 oz/yd2 climashield garment would provide 1.2 clo.

So, if you wore a 1.5 oz/yd2 Climashield garment inside a 4 oz/yd2 Climashield quilt, it would be good down to 40 F using EN13537 lower comfort limit assumptions

[Matt Keenan]

So what is clo? How is it measured and what is the formula for calculating warmth rating from the clo value. I have seen that pirmaloft gold has a clo of .92 what does this mean that it would be warmer for the weight than apex

[Jerry Adams]

clo is a unit of insulation. 1 clo = the insulation value of a standard suit of clothing. A lot of U.S. people use that unit.

it's like R value in house insulation, except it's a different measurement unit – 1 clo = 0.88 R

and there's a metric unit Rsi – 1 Rsi = 0.176 R – more common in Europe (the more highly developed part of the world : )

read that mammut document – it talks about it and how many clo or R or Rsi you need to be warm down to a given temperature

[Matt Keenan]

Thanks for the explanation Jerry and for finding and posting that article lots of good stuff in there.

[Jerry Adams]

If you were an "M" or "Mlife" person you could read articles by Roger, me, and Matthew Morrissey on how to measure : )

[kevperro .]

Thanks for the link. I just bought the Prodigy Tim makes and I'm very happy with the purchase. I've not put any trail nights on it yet so I'll reserve final judgement.

The last synthetic bag I bought I swore was my last so I'm eating crow…..but happily eating it at the moment. If I get 3-4 years out of it I'll consider it a success.

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