Down Loft Standards

[luke_vic]

When comparing sleeping bag temperature ratings the EN system is a great tool to compare different products back-to-back. However, I have recently read that there are different rating systems for loft values, for instance 850 loft US is equivalent to 750 loft EN. This makes comparison difficult, especially as most manufacturers don't specify which system they use (EN or US).

More reading on page 3 of the following buying guide (follow link) http://www.bogong.com.au/html/sleeping_bags.html

Does anyone know more about the differeneces in the two standards and what systems some of the manufacturers use (ie Macpac, Marmot, etc)?

[photohiker]

Looking through the literature I collected the other day:

One Planet uses the US cuin/oz measurements
Mont does not say, except that they rate to the lower loft of any test.
WM does not say, but given they are talking 850 and they are in the US it's a fair guess they are using US cuin/oz
Kathmandu does not say.
Mountain Designs does not say.
Macpac doesn't say directly, but refer to "90/10 European goose down with 750 loft" online (Sanctuary 500 light XP) Being in Adelaide, we don't have a Macpac store to ask
Marmot (online) "Certified 800+ Fill Goose Down Independently Tested and Certified by International Down and Feather Laboratory in Salt Lake City, Utah." (Pinnacle Long) So probably US cuin/oz?

It's a can of worms

[Franco]

With some brands you can get the EN 13537 if you look at the info on their UK wholesale or retail sites.
For example Marmot
http://www.ukclimbing.com/gear/news.php?id=1176
Macpac
http://www.needlesports.com/acatalog/Ma ... c_225.html
Exped
http://www.exped.com/exped/web/exped_ho ... enframeset

The temperatures listed by Western Mountaineering are pretty accurate (usually defined as "conservative " in the US)
http://www.westernmountaineering.com/in ... ing%20Bags
(comparable to the EN comfort rating, however for loft see the Bogong comments)

1)A good indication is the loft and the cut. With two bags having the same wiggle room , the puffier one will keep you warmer.
2)There is a minor variation due to the density of the loft but no consensus on this point.
3)Also some think that lighter fabric gives a higher loft but does not retain heat as well as the heavier type.
4)Some also think that with high humidity the higher loft bags (800-850...) will collapse more than the lower ones (600-700) therefore reducing the difference in performance

My impression is that No 1 is the most relevant ( after reading many comments from people that have owned several bags)
Franco

[luke_vic]

Thanks for the info photohiker & franco. Franco - just to clarify, it's the EN 12130 standard versus US method in question in regards to loft measurement. I think EN 13537 is excelllent for comparing temperatures and you're right - most brands are testing to this standard, which is good for the customer. However the down loft quality is less easy to compare from one brand to the other, as EN 12130 is not referred to by many brands when they publish their loft values.

[Franco]

Hi Luke
Yes the EN 13537 I refereed to is the temperature rating, EN 12130 is the "fill power" generally called loft.
If you are not purchasing down for your own use (DIY projects) generally speaking because of some of the factors I outlined in the above comments, to the end user EN 13537 is more relevant than the other figure.
Usually once you know the total weight of the bag, you want to know what bag will keep you warmer for the least weight and (for some) smallest stored volume, for what you can afford...
I know how down can be "puffed" up to get higher ratings ( the American way) however I am not aware* of a way of cheating with warm ratings using the EN 13537 standards.
* well , a "tighter" bag will do that , so make sure the bag fits you before you get all carried away with figures. If you compress the down by pressing against it , you lose warmth. (same for a short tent....)
Franco

[luke_vic]

All valid comments. However, fill power is still an improtant factor to know, as it gives a good idea of the quality of the bag and whether or not the guy in the shop is ripping you off. For example, Mr Macpac could say that his 800 loft bag has a superior fill compared to to a Rab 750 loft bag, and he may command more $$$ for this feature. However if Mr Macpac uses the US standard and Rab uses EN, then the Rab actually has a superior fill power (note 800 fill power US is approx 715 fill power EN, according to the document in the link above).

[Franco]

BTW, the cost of the EN 13537 is about 1500 Euros, that is around $2600 per bag. Add to that shipping and administration and multiply by 10 or 20 ( or whatever your range is) and it becomes a fairly expensive exercise.
I have seen a quote for EN 12130 as low as 52 pound sterling, about $105 , but that would vary from batch to batch.
Have a look at this :
http://www.idfl.com/articles/warmsoft.asp
Franco

[photohiker]

we have received sleeping bags for military use which are stored in compressed rockhard blocks.

Now I don't feel so bad about stuffing the bag for a few hours into a stuffsack

[rcaffin]

Hi Guys.

A very brief and somewhat cynical and biased explanation of loft standards.

In the beginning ... there was the familiar scale of cubic inches per ounce. An imperial Standard.
The the Europeans came up with cubic centimeters per gram, which works out about half the previous one (so 800 loft translates to about 450 cc/g). A metric Standard.

But then some USA down users (bag makers) wanted to have higher loft ratings wholly and solely for marketing reasons. So International Down and Feather labs (IDFL) (who do a lot of the measurements) came up with a way of conditioning the down before measurement which allowed them to claim that what used to be 800 loft was now 900 loft. They jammed that conditioning method through the Standards process, over the objections of many (especially the Europeans). This made a second imperial Standard.

The problem is that the new IDFL/imperial Standard requires that the down be dried to an artificially-low level of humidity before measurement. The drier it is the stiffer it is, which gives it extra loft. The problem with such a low level of humidity is that it is completely unrealistic in the field. It is hard enough keeping your SB reasonably dry at the best of times. The Europeans are very sarcastic and even sometimes hostile about this.

So ... you will find that some European companies now quote THREE loft values: the old loft standard, the European loft standard, and the 'USA' standard. You will find that the Europeans can be pretty scathing about the 'USA' standard.

For us, the problem is that when you see '800+ loft' you probably have no way of knowing which of the two imperial Standards was used. A cynic would say ... ...
This means that the only reliable Standard now is the European/metric one, but be prepared to see ratings of half the old values. Change of units, that's all.

The One Planet web site now quotes to the European standard for bag ratings. I think their loft ratings are to the old imperial Standard, but I am not sure.
Oh yes, while I am at it: do NOT expect to use your bag to the 'extreme' temperature. That temperature is for *survival*. It bears no relation to any concept of comfort!

Cheers
Roger

[luke_vic]

Hi Roger,

Thanks for your very thorough explanation. While your answer is not straightforward, it sounds like the different ratings systems themselves are not straightforward! Is it best to ignore the loft ratings from manufacturer’s altogether and compare bags with their {EN temperature rating} / {down mass} ratio for instance? Unless we are 100% sure the bags in coparision have the same loft rating system that is.

Cheers
Luke

[Ent]

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[Nuts]

Everyone gleans the figures for what they are hoping/what should be a once in ten year purchase. From what ive found, even though standards vary, bags from the reputable manufacturers are reliably rated by their own standards. You only have to look to the positive reviews, the manufacturers that have a good reputation get good press, perhaps even win awards.

The standards are meaningless unless youve used a bag from the rating. As mentioned, some people wouldnt even be in the season rating let alone need to look to standards

The proof really is in the pudding. I know some people like figures almost as much as getting out there but you have to realise that there is no magic in figures. He..ck, youll make a list, decide on something then find one (down the list) on sale at a price that cant be ignored. After all if its not to save a $ then why not just walk into a store and buy something you can touch?

carry on....


BTW
Its interesting that a lot of people covet WM bags... Is this because they are sold here?
They do get good press but then many others do also...
They seem overpriced compared to bags from companies with equal standing in the US?

[Ent]

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[photohiker]

I agree with all that, but I also think that Nuts is on to something. Having the bags on display eliminates some of the uncertainties. In my own case, I was able to see the OP and the WM bags in person, and it was very clear that both are quality products. Pity the imported bags end up being so expensive at retail though. In the end, it was features (the full length zip mostly) that steered me towards the WM bag.

It's only a little thing, but the use of cheerful colours was not lost on me either. If two bags were identical, I'd rather wake up to some WM colour than the OP Cocoon muddy brown.

[north-north-west]

Oh yes, while I am at it: do NOT expect to use your bag to the 'extreme' temperature. That temperature is for *survival*. It bears no relation to any concept of comfort!

*shiver* I kinda noticed that one memorable night my first time up at Pine Valley when it started snowing and there was no dry coal so the stove wouldn't work. Geeez that hut's cold . . .
Thanks for the info. Very useful, something to keep in mind next time I go shopping.

[luke_vic]

Try being over 6'3" looking for say a minus 10 bag with Gore-tex Dryloft that is not designed for a super model and then the field narrows.

Hi Brett,

Which WM bag did you end up purchasing & what size? Where did you buy from?

[Ent]

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[climberman]

So, reading between the lines, a OP loft of a 'lower' grade is likely to be the equiv of a WM or Mont-Bell of a next grade up ?

OP starting to look very good on those numbers.

[Ent]

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[photohiker]

Just to be clear on an unclear subject.

OP claim 800 loft and WM claim 850 loft. No-one has identified by which standard those ratings are delivered, so the best we can probably say is that they are both using some of the highest lofting down available. I wouldn't make these small differences at this level reasons for choosing one bag over another.

[climberman]

Ta Brett, and p-h. I am leaning further towards a One Planet bag, poss with an extra 50g stuffing. This has been one of those enjoyably informative little threads.

[Nuts]

Moved (Your right, I think its reading those rambling posts that throws me)

[photohiker]

Suprised in SB discussions that no-one has mentioned better alternatives to Nylon as a shell fabric?

What about ethical manufacturing standards?

All ears, tell us more.

Should this really be in the SB topic rather than the Down topic?

[luke_vic]

Moved (Your right, I think its reading those rambling posts that throws me)

Can't find the original post - but did you say you have 40 sleeping bags???!

[Nuts]

hmmm, dont know what happened there... anyhow, just mentioned that there were other factors that hadnt been discussed that may/or not influence buying. There are also US (and likely other) manufacturers on par with WM, that there are some who have various sizes and cuts within models and that there is 'better value' (I would use 'IMHO' but i'm sure anyone would agree if they had the chance to see all these bags side by side 'un-labeled'). Yes 40 or 50 (its a job lol) We went with Marmot, they are very well made.

cheers nuts

[blacksheep]

Who makes one case and fill with a range of fill weights?...that is a major compromise and will more likely result in uder performane (either through heat loss or expensive down not lofting to potential) Each of our bags have very specific baffle heights and fill charts-calculated for maximum effeciency (then slightly over filled by 3-5% to allow for ageing affect performance drop)
WM bags are nice, but I would rate our new santuary XP bags up there with them too.

[Ent]

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[blacksheep]

t I would rate our new santuary XP bags up there with them too.

Assuming one could figure out the sizing. The XL bag is a who 30mm longer which in the old language is 1 1/4 so hardly worth the effort. Seriously I hope that I misreading the table our your web personal need to go back to school to understand the difference between MM and CM. Else you make really, really, really, small backs. Check out the link. http://www.macpac.co.nz/product-support/sizing

Cheers Brett

lordy..
have passed it on.

[Ent]

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[blacksheep]

those responsible will be paid in cents instead of dollars