bag temp ratings

3:12 a.m. on November 1, 2011 (EDT)
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maybe someone can shine some light for me,bag temp ratings seem like voodoo witchcraft are manufacturers acknowledging or complying with any industry standards? i know of european standard EN 13537 but have us manufacturers or distributors even acknowledged and/or complied with any adhoc standard.does anyone know if FTC even monitor any claims of manufacturers?does U.S. have any measurement standards for manufacturer claims,if so what are they and how do they compare w/european EN 13537,also which rating is advertised"comfort","lower limit"or"extreme"?

7:58 a.m. on November 1, 2011 (EDT)
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Wlcome to trailspace

 

 

 

 

 

 

 

unk..

That subject has been brought up a few times and I ask the same question myself at times. Atually it's 2 different units of measurement used and procedures.Here is some outlines from the past to describe the procedures used and helpful information from Brumo. www.Trailspace.com/forums/Gear-Selection/topics/91375.html.

 

 

another by Brumo is www.Trailspace.com/forums/Gear-selection/topics/90935.html.

 

add in Oclacomputerguy asked about bag temps here. www.Trailspace.com/forums/Gear-Selection/topics/92522.html.

After reading brumo's explanations I understand the difference. Because the testing procedures are different in Europe to North America. I hope that helps you some. It still doesn't explain why it's not one standerised test on both continents.

 

 

 

 

 

 

8:14 a.m. on November 1, 2011 (EDT)
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did a little research on bag temp ratings"ASTM F 1720-06"is the only U.S. thermal standard utilising heated mannequins for sleeping bags.there are also loft measurement standards"ASTM F 1932-38".the only sleeping bags with european "EN 13537" standards in U.S. are the north face,mt hardwear and marmot.bags in U.S. using "EN 13537"use "comfort rating" for adult women.REI adopted "EN 13537",until there is uniformity approximate by fiil material,fill weight and design geometry.happy camping,stay warm

11:39 a.m. on November 1, 2011 (EDT)
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unk said:

bag temp ratings seem like voodoo witchcraft are manufacturers acknowledging or complying with any industry standards?

Not exactly voodoo witchcraft, mostly marketing. The big problem is that there are so many variables that have nothing to do with the bag itself. These are discussed at length in the posts linked above and many other threads here on Trailspace.

The biggest variables are your personal genetics (some people sleep cold, some sleep hot), fatigue, food you have eaten and how recently, your hydration level, in a tent or not, what's under you (foam pads provide insulation from the ground, or snow in winter camping, air mattresses and cots tend to be cold because they allow lots of air circulation and convective cooling), and so on. The European standard is an attempt to cover some of the variables. Years ago, various military agencies, mainly ones that had to deal with winter warfare, did a lot of testing with soldiers (mostly young, very fit, very macho men) and came up with a rating system based on thickness of fill in the bags. In the 1960s and 70s, instrumented dummies with heaters to simulate body temperature were introduced and improved. Each company developed its own testing methods.

The result is that some companies tend to be optimistic in their ratings, and some are pretty much dependable. If you stick with Western Mountaineering, Feathered Friends, Valandre, and a few others, you will be pretty close (these tend to be on the expensive side and also are harder to find). Some big names (TNF for one) seem a little optimistic, and other names (such as Wiggy) found in the major chain "outdoor" stores seem very optimistic.

Loft (thickness of the fill) and type of construction (box, slant box, V-baffle, sewn through, lots of other styles), bag shape (mummy, rectangular, ...), and other construction features can be dependable measures, once you "calibrate" yourself. The kind of insulation itself is not that important as far as the warmth is concerned - same construction and same thickness gives pretty much the same warmth, whether it is down or synthetic. The fill does make a huge difference in weight and "stuffability" and cost.

6:17 p.m. on November 1, 2011 (EDT)
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I look at bag ratings with the same skepticism that I look at tent ratings and numbers . First of,  I think I know gear well enough that I can usually pick out the finest gear to suit my needs my reading the real test ratings. Those of the people who have used the piece of gear long before I even started looking at it. I watch with much amusement as people buy new gear only to have it not meet there needs before it's been time tested. If you buy new and it does not work you have to sell it used. If it has a know flaw that is disseminated to the public befor you can unload it then you have a lightly used flawed product.

I have a friend that likes to buy the newest model motorcycles. He buys the first year model because it's cool, and yes he pours over the numbers and specs. But numbers and spec are great on paper and in the testing phase but quite often have very little application to real world use. It's like that with gear. I love to see and hear that others are buying new gear so that they can test it out for me and I can see if I want it. Then by the time I want it there is enough of it out there on the used market for me to get it at half price. I do not understand the thought process that would allow a person to buy a untested product for lots of money (full price) when they can wait a year or two and buy the same product for 50% (or less) and get it unused condition quite often to boot.  Remember once you walk out of the store it's used, even if it has the tags on it.  New means I get it from the store or the maker.

The numbers mean nothing if the item does not perform in the field. I know that if you line up a bunch of tents and asked me to pick out the ones to meet certain needs that I can do this without the "numbers". I'm confident that I can do the same with sleeping bags knowing only the loft, fill, material used inside and out. The numbers mean nothing to me and I have never even looked at them. The numbers mean nothing when your in your highly  rated, by the numbers, bag and your freezing your tail off.

With all that being said if people didn't buy new stuff, numbers or not, then there would be no used equipment for me to buy numbers or not.

I have never in my life bought anything gear wise based on test numbers.  Never say never but I can't think of a time when I would unless it is in reagrds to climbing equiptment, ropes and carabineers and the such.  Everything I do requires me to know if an item works and how it works not how it might compair to other items by the numbers, esp. when no one is using the same numbers.   Each to their own.

 

 

9:24 p.m. on November 1, 2011 (EDT)
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I say, forget about bag ratings.  Here are the important numbers:  Fill power and fill weight.  As Wikipedia says,

"Fill power is a measure of the loft or "fluffiness" of a down product that is loosely related to the insulating value of the down. The higher the fill power the more insulating air pockets the down has and the better insulating ability. Fill power ranges from about 175 cm³/g (300 in³/oz) for feathers to around 900 cm³/g for the highest quality down."

Ergo, we look for a bag using the highest quality down in the 850 to 900 range.  Most quality bag makers like Feathered Friends and Western Mountaineering and Valandre use the highest fill power.

After this number is figured out (and it's usually left to the company making the product), the most important number is Fill Weight.  Many bag makers and parka or jacket makers don't even list the fill weights of their items, so a customer is stuck and has to rely on the rating number---not good.  Every down product made should be required to carry the fill weight number.

I remember in the old days bag makers using around 38-40 ounces of down in their bags would sell them as very robust winter bags geared towards mountaineering in subzero temps.  In other words, while a bag might be rated at 0F, if it has only 28 ozs of 600 fill, well, I'm not interested.  If it has 850 fill with 35 ozs, well, let's check it out.  And as Bill S says, bag construction also comes into play, but most good bag makers follow tried and tested designs.


11:28 p.m. on November 1, 2011 (EDT)
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If a company is selling bags in the EU, they have to be EN rated-

http://en.wikipedia.org/wiki/EN_13537

You would think they would settle on ratings for the same theoretical person, but they don't, which makes no sense to me. Some makers (MacPac for one) shows the ratings on their website-like this-

http://www.macpac.co.nz/shop/en_nz/gear-and-clothing/sleeping-bags/sleeping-bags-mountain/sanctuary-600-xp.html

My MacPac bag is pretty close in rating, at least for me. It's rated to -5C (+12F) and that is about right if I have my Capilene on and a beanie and socks.  It might be a tad optimistic depending on how I am feeling and how much I ate. 

My bag cost nowhere near what their prices are now, but I've had it a long time.

I would not want to be in a bag at a temp that was lowert than the comfort zone, I would be cold. If I was buying another bag I'd be asking them about their rating before buying. No idea what kind of answer I'd get, though.

11:55 a.m. on November 2, 2011 (EDT)
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You would think they would settle on ratings for the same theoretical person, but they don't, which makes no sense to me.

But, as noted earlier in this thread, people differ greatly in their comfort level. That is the point of the multiple rating numbers. There is a difference between men and women, between athletic/active people and less active people and so on. The 4 levels are defined as follows added emphasis):

  • Upper Limit — the temperature at which a standard man can sleep without excessive perspiration. It is established with the hood and zippers open and with the arms outside of the bag.
  • Comfort — the temperature at which a standard woman can expect to sleep comfortably in a relaxed position.
  • Lower Limit — the temperature at which a standard man can sleep for eight hours in a curled position without waking.
  • Extreme — the minimum temperature at which a standard woman can remain for six hours without risk of death from hypothermia (though frostbite is still possible).

It isn't a perfect system, since comfort does depend on fatigue, and other factors that were discussed on a number of earlier threads.

12:06 p.m. on November 2, 2011 (EDT)
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I use a cheaper 40 deg synthetic bag for warmer conditions. Granted I could use a down bag that compresses to the size of a softball but that really isn't a big deal to me. 

The bag is a TNF Wasatch. It does the job and when it comes to gear that is priority 1 for me. 

I wanted to post the pic below as a reference to an EN rating. 

EN-Rating-004.jpg

12:06 p.m. on November 2, 2011 (EDT)
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One more thing to think about is bag width.  Over the weekend I used a much wider cut bag than I generally use and I found it hard to stay warm - I just could not warm up all the excess space inside the bag.  The bag had enough loft to keep me warm, but too much interior space for me to fill.

12:52 p.m. on November 2, 2011 (EDT)
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Rick-Pittsburgh said:

I use a cheaper 40 deg synthetic bag for warmer conditions. Granted I could use a down bag that compresses to the size of a softball but that really isn't a big deal to me. 

The bag is a TNF Wasatch. It does the job and when it comes to gear that is priority 1 for me. 

I wanted to post the pic below as a reference to an EN rating. 

EN-Rating-004.jpg

I have 2 bags with the EN ratings. I can push both of them into the limit range,. But I wouldnt go to the extreme with ether of them. 

I have found that fit is very important in keeping warm. A bag that is oversized will not keep you as warm as a snuggly fit mummy.

1:09 p.m. on November 2, 2011 (EDT)
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Hey Mike, I have actually taken the above bag into the mid 30s with no discomfort so this kinda goes with what Bill spoke about previously that it is somewhat individual when it comes to temp ratings. 

Some just sleep warmer than others. 

All of my bags are mummies. 

1:18 p.m. on November 2, 2011 (EDT)
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All my bags are mummies too. I had one that had a temp rating of 20. It was oversized for me and I only used it once. I froze at 50.

1:23 p.m. on November 2, 2011 (EDT)
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Woah... Rated at 20 and a "Mike-sicle" at 50. Guess its safe to say that rating was a bit off. 

My mummies are all pretty snug. For me if there is a substantial amount of room in the bag I typically send it back. 

1:42 p.m. on November 2, 2011 (EDT)
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I did a review on it. I blamed me and the maker. I sold it to Gary who sold it becouse it was to tight on him.

10:40 p.m. on November 2, 2011 (EDT)
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I have a BA rated for 0. I found ratings that made itlook like I should be pretty good in it, though it has only been rated once. I also have a liner and the insert-able, inflatable pad ADD to that I will be in unheated tea houses on cots so not quite the tent on the ground experience. i will rate it when I get back in April and should have a good amount of beta on it given it will be 17 or18 days in it n altitude from 10k to 17.5k so temps wil vary all along the way.

11:38 p.m. on November 2, 2011 (EDT)
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wow,a lot of useful information but i dont want to be told what temperature rating bag to purchase for sleeping in a specific temperature,just need a reference.maybe labs should assign a numeric value with a non-dscript unit of measurement.if people are hard to design bags for maybe the labs could use some other warm blooded animal for testing.at least we would have a reference,as long as there's universal compliance.

2:06 a.m. on November 3, 2011 (EDT)
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I think if you look in the articles section here you will find a very good write up about this very point

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