EN13537 vs US based Temp ratings

[Michael Cheifetz]

Roger/Richard – glad you chimed in (the physics cohort): obviously the standard is far from perfect though im sure its not that hard to improve (as the liked doc by @James shows) but as others have said:
1) its STANDARD – so i can compare bags by diff mfg – which in reality is all i can expect
2) It INTEGRATES all the bag design features (like draft tubes) since it measures overall and allows for certain air speed (btw – i would add some airspeed as a mandate)

Its clear that personal, design and environment factors can change this greatly – but that can never be modeled (although you could have labs where just INDIVIDUAL CONSUMER would be tested to determine some reference of his/her heatoutput) but the standard is WAY WAY BETTER than nothing.

RE cost and the cottage industry – i would love to see any of them chime in here cause i simply dont buy this argument: in EU its mandatory so maybe a big name like RAB or MAmmut need to test every single configuration they have. but if nunatak or MLD would just test ONE SINGLE bag of their most popular models that would be a HUGE improvement.
now lets get real – how can the profit margins be low for a cottage mfg??? if we buy bags @300~600USD for a 20F bag????? they dont really hold much stock, there is no supply chain to upkeep, no distribution chain to manage????? Most of them reside in low rent areas and have small shops…
I assume that their profit margins are at least 50% gross margin if not more like 70% which any retail or lifestyle company would murder for.
So IMO nothing will happen to Nunatak, MLD, Zpack, Katabatic, JRB, Enlightened if they spend 5000USD a year on testing and im sure if they get together to do it they can figure a way to get it done cheaper.

As for self experience and other's experience: guys as i said experience is crucial – but lets look at the numbers:
the super active people here on BPL who log 100 trail days a year are the absolute minority in the world. IF BPL wants to help bring the vision on lightweight to the masses then they need to be able to help people like me or others that might have alot of brains, fitness and theoretical knowledge but can travel only a few times a year.
Yeah – I could take my 10F Nunatak to trips where temps are only 25F and be safe – but that aint UL is it??

I will end with quoting from Ron Bell's website (disclaimer – I REALLY LIKE his stuff)
First: "At MLD we have thousands of users reports from the field over the last decade and we go our own way" – but what does that mean? If he would say that "from our studies a 30F EN bag is realistically a 25F bag" that would be fine

Peace
Mike

[SnowMania]

5000USD can only allow someone to test less than 10 pieces of sleeping bags on EN rating, it probably only ables to test a few sleeping bags on an top-tier, certified and reputable laboratory only.

It costs 130 pounds to purchase the standard only, if you have a deep pocket you can always purchase it at:

BSI online Shop

I have a chance to read through the EN standard once. I can tell you that there are specifications on the baselayer wearing by the manikins and the pads. If you ask nicely Richard probably may give you more details in this regard. I am sure he has the standard on hands.

By the way, there is no official measurement of quilts defined in that standard, through the manikins should not refuse you to put it into quilt mode, than the sleeping pad become a major factor affecting the measurement's result.

[Michael Cheifetz]

@Sam
I realize what the cost is – my point was that say a cottage mfg has 3- 5 different models in 3 legths and 2 widths with 3 shell options – so yeah sure if you want to test ALL OF THEM that will be an issue but why do we really need to go that far? IMO testing just a few will create enough data points to make a difference since they share so many common traits (usually baffle height, draft tubes and geometry are very similar ona certain model regardless of width and length)

Say Katabatic would test the Palisade 30F Regular width reg length…and find out it is rated 40F Lower limit…that would be interesting wouldn't it?
and Zpack really only has one type of bag currently….and MLD have one quilt type…and enlightened have 4….i guess even nunatak that have quite a few still many common design traits.

And regarding the pad – that is IMO a minute issue – lets all decide to take the pad out of the equation and decide to use and Exped downmat 9 for these tests and cinch the quilts down all the way.

I am willing to pitch 100USD of my own money in a BPL user pool to see a test or two done :)

Mike

[drowning in spam]

The standard requires a mat with a thermal resistance of 0.85 m^2 K/W. It also says that sleeping bags with a hood require that the manikin wear a face mask if the sleeping bag has a hood. Since quilt users wear headwear when it's cold, shouldn't some sort of insulated hat or balaclava be part of the test too?

[Dirk Rabdau]

I fail to see the upside of certified testing for any of the small cottage producers. Unless sales are negatively affected by the lack of a certification, I can't see anyone spending the money necessary to garner a rating. Do you? Am I missing something?

If you compete bags and quilts solely on temperature rating, the small manufacturer is likely to lose, since such producer is likely to see his or her bags/quilts at higher cost than larger manufactures. (Fewer bags produced and sold, higher raw material costs, likely higher labor costs). I would imagine most cottage manufacturers would rather be judged upon factors including design, cut, comfort and weight. Temp rating is a consideration, of course, but like a digital camera, you can't judge the system entirely by the size of the camera's sensor.

Obviously, some will overstate the quality and rating of their bags. They will most likley incur punishment in the marketplace for such actions.

Dirk

[Richard Fischel]

buying/selling the maker's reputation and word-of-Mouth recommedations. these products don't sell because of some international rating system. they sell because they have a good reputation and the product is talked about and in many instances you can interact on a personal level w/the nanufacturer. en testing would cut into profit too much to ad any value.

[Michael Cheifetz]

@Eugene – of course you are correct, some standard headgear is needed for a quilt test.

@Dirk @Richard Fischel – Truthfully I dont understand what you are talking about??

A bag can be designed elaborately as the Space shuttle but at the end if it aint warm enough its worthless and the lack of some type of standard is a real world problem. I think what happens in reality is that we buy very well made cottage gear that usually tries to cut weight at the expense of SOMETHING….which sometimes is warmth. And we the users since we are so used to layering and sleeping with our clothes and such might be mitigating (so say im sleeping at 30F with what is really a 40F bag…but i wear my jacket to bed or layer on top of the bag and am used to being slightly cold, and maybe wear gloves inside and a warm hat – so great i made it and was fine but its STILL JUST A 40F bag!!

Also – real world problems – say you are switching to a different style (quilt vs mummy vs suqare, vs down, vs synth etc) how can you compare? Or moving from 3 season to 4? I agree people's opinions help…but that isnt enough. As an EXAMPLE take a look at zpack quilts (which i am looking at presently) they are quite new on the market and there is no real data – so what now??? wait 18 months? pray? base my 400USD decision and my next 2000USD trip to Scotland on opinions of 3 people?
If it were tested i could have compared it to my MLD quilt or my WM bag or nunatak bag!

As per profit margins – I could be completely off here but if i am please someone who knows the numbers chime in.
In any industry i know "cottage" means super high profit margins and low volume. All the cottage industry has very low distribution costs (basically WOM viral) and super low inventory and supply chain costs unlike say WM or TNF who have HUGE costs in the above. I dont know how much the raw material costs and I assume the seamstress gets paid better than in Thailand but would bet they still have 50~70% gross margin and the prices are way higher than your average joe bags

Mike

[Jerry Adams]

In the example given in the mammut pdf

$1500 per test

typical manufacturer has 30 different sizes and models – $45,000 total. Plus they'de have to spend an equal amount changing all their marketing/hang tags/…

6% of total sales is all they can afford to spend on testing, so they have to sell more than $1,500,000 per year for it to make sense

Not too many manufacturers sell that much in sleeping bags

[James holden]

what gets me is not cottage manuf not testing … they dont have the volume and their cliental really dont care too much … you know yr taking a risk buying from them

its a fair sized manuf like montbell not testing their bags …

note that many people here and the BPL SOTM test generally agree that the montbell 30F bag is one of the least warm ~32F bags … so they would possibly have to reset all their ratings or change the fill for that bag anyways

REI to their credit did exactly that when they went to en-ratings

what en-ratings are great for is that it doesnt allow the manuf to hide behind bogus ratings …

[SnowMania]

@Eugene The value of 0.85 m^2K/W +/-7% (around R = 4.8) indeed is defined at the standard. I simply want to emphasize sleeping pads playing a more important role on the quilts test than the sleeping bag test, as about 1/3 of manikin's surface only having a single layer of the baselayer to insulate between the pad and the "skin", in comparing with sleeping bag, where this area of manikin's surface is insulated by a layer of baselayer, plus 2 layers of shell fabrics and a layer of compressed down or other material.

If such a test ever conducting, certain kind of insulated hat or balaclava needs to be standardized as part of the test, I believe if the manikin simulate a real mankind better, the heat loss from the head will have more noticeable effect on the test result.
(At least someone suggested that 1/3 of body heat losing from the head.)

[Roger Caffin]

Hi James and all

Yes, I know the people at Kansas are not enthused about the EN standard. However, bear in mind the following:
Kansas U has been the main test lab for bags for America
Kansas have not offered the EN test in the past
The American test results have been ridiculed by many
European testing to the EN standard must be cutting into the Kansas income.

That is not to say that the EN standard is perfect: I am sure it is not, and I am sure some of McCullough's suggestions are good. The Europeans have ackowledged that it has some loose ends. But I think the loose ends are fairly minor – especially when compared with the wild claims some American bag manufacturers make.

However, I do have a small problem with some of McCullogh's statements, such as "We have examined different pad pressures and found that they did not make a difference in the overall insulation value when the pad was placed on the board." This is at marked odds to the previous paragraph which states "Research has shown that the pad can make a huge difference in the insulation of a sleeping bag system". The data at the end of the paper shows that the pad does have a significant effect – as we found when we tested air mats at various pressues.

Cheers

[Dirk Rabdau]

Michael –

I was merely asking what would the advantage for a cottage manufacturer to invest in the test? I agree with Richard, the decision to buy a bag isn't made solely upon specs. There are other less tangible and frankly, emotional and preference issues that go into the purchase.

I agree that temperature rating is important. And I agree that the EN test would be a great standard by which to base all bags. My argument was merely that I have reservations as to the advantage any small shop would garner by the test result. I think most buyers of boutique goods (which cover your small cottage manufacturers) do so for reasons other than a singular rating.

Do I think that bag companies should strive for a more unified, scientific bag rating system? Yes. Do I think that it makes economic sense for smaller producers? I would say that I have my doubts, considering the cost of the test and potential impact that not having a certification would have on sales. If the test were less expensive, maybe my opinion would be different. Jerry and Eric more effectively express my sentiments regarding the subject.

DIrk

[James Marco]

Hi Roger, I hope your Christmas was pleasent.
I agree that Elizabeth McCullough's paper is not well written. She points out some problems with the EN standard and its adoption generally, and, does it in an inconsistent manner.

My thought that the EN system is so far superior than the American system it doesn't make sense NOT to adopt it. But this does indeed incur a cost. It is therefore vital that it is a corrected standard as well, not to obsolete all the good effort so far accomplished.

[SnowMania]

Though I believe McCullough is one of the authority in this field, unfortunately the main purpose of the paper archived by OIA is try to downplay the important of EN13537. In fact, in my own eyes, she lost certain credibility with this paper.

If she really want to do something good in a science way, a proposal on ASTM standard as a refinement based on the EN standard should be a good approach. It has been almost 10 years after the EN standard was approved by EU, there are certain progress regarding measurement technology during this period. The manikin "Charlie" mentioned at the standard only have 15 segments, but now a manikin mentioned at recent French lab reports already has 35 sections. It probably can specify easily a pad with +/- 3% for lab testing instead of original 7% now.

[Roger Caffin]

Hi James

Yes, Xmas was very pleasant.

After we returned from our regular 2-month European walking holiday in the middle of the year I found the grounds around house had been hit by lightning – it does happen here. My main hard disk had been trashed (no spin) and my stand-alone Maxtor NAS backup was locked up by the aberrant Maxtor SW. Effectively, I had nothing from the last 15+ years of walking, designing, research (work)…. Don't ever buy a Maxtor NAS! (Comments on the net are not favourable either.)

But, the day before Xmas, the data recovery people sent me all the 100+ GB of data off the Maxtor! All my photos, all my articles, all my gear designs, everything!

Happy Xmas indeed!

Cheers

[Roger Caffin]

Hi Sam

> a manikin mentioned at recent French lab reports already has 35 sections. It probably
> can specify easily a pad with +/- 3% for lab testing instead of original 7% now.
Which is verging on the needless. What manufacturer ever makes two sleeping bags or quilts with the fill within 3% of each other?

Yes, Kansas and McCullough have a problem – which could be easily and quickly fixed as you suggested. But … not invented here!

Cheers

[Bob Gross]

Roger, you could dump a lot of data that onto one single flash drive and then hide it in a secure place, like your pants pocket.

Many people think of a lightning surge as being a high voltage spike that comes through the power phase wiring and "fraps" your sensitive appliances as it flows toward ground. In fact, much of the time the lightning hits the ground outside and causes a ground potential rise. Then, the current surge actually goes in the reverse direction, from ground toward the power phase wiring. Damage can be done either way.

–B.G.–

[James Marco]

Roger,
Yeah, I know how that goes. I lost a bunch of stuff a couple years ago. I made regular tape backups and bi-monthly snapshots, but this last time also took out the tape drive. The new machine will NOT accept the old hardware of the last tape unit I have. Soo, I have the data, tapes and hardware. I have a new machine. They just DO NOT play together well.

Anyway, glad you had good recovery!
jdm

[SnowMania]

More than 100GB data is not easy to handle by USB flash drive which mostly available in the size of 32G or 64G, but can be handled by 320G SSD in the form factor of 2.5" external hard disk. It is quite expensive, but I believe still cheaper than the one time service change of the data recovery services. Good to be used as off-site backup media of the NAS.

Btw, the fault rate of my Maxtor HD in the size more than 100G is extremely high, 2/3 of my Maxtor drives needs to be replaced in one to two years after put into service, it is probably why Seagate so easy to buy up Maxtor.

[Roger Caffin]

Hi Bob

Yes, I know, I know …
For the technically minded:
Our whole network is powered by a large ferro-resonant isolation transformer. That could be described as serious paranoia – except that I have seen lightning before. It is normally extremely reliable. So why did the lightning strike cause damage?

Because I had one silly little plug pack driving some small speakers hooked to the UNfiltered grid! That's why!

Yes, ground bounce, and neutral bounce. Sigh. (That plug pack has been moved!)

Putting 100 GByte onto USB SS thumb-drives – not a realistic option today imho. Instead I have one 500 Gbyte backup drive inside one chassis, backed up every night with regular checks for readability, plus one or two 500 GByte USB external drives which get backed up onto every few days. Incremental backup is used: any file which has a later date than the matching file on the backup drive gets copied over. No deletions.

Talk about thread drift! SORRY!

Cheers

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