MH Lamina Series: True to Temp Rating?

MH en rates their lamina and ultra lamina and most of their other bags

most of their bags range from accurate to mildly overated as per the en-tests on their site

most very (below 0F) cold weather bags are not en-rated regardless of manuf

REI carries the 0 degree (but not the other two you mentioned) and show EN ratings:

Specification Description
EN lower limit (rating for men) 10 degrees Fahrenheit
EN comfort (rating for women) 23 degrees Fahrenheit
Temperature rating (F) 0 degrees Fahrenheit
Temperature rating (C) -17 degrees Celsius

(FWIW)

Thanks Eric.

"most cold weather bags are not en-rated regardless of manuf"

Yes, it's these non-EN-rated versions of the Lamina I'm most interested in… do you feel they continue to be accurate when they can no longer use the EN ratings, or do they begin to exaggerate once no longer using the EN ratings?

That's interesting Jason… so if this is accurate, it implies that the overall rating they are giving out (0F) is likely exaggerated by 10F or so?

Although on MH's website it says they don't do EN ratings for bags 0F and below, so I wonder if REI has the Lamina 0 tested independently?

My Mt'n. Hardwear -20 Polarguard Delta bag is heavy and bulky (won't fit in my pack). But it does have one redeeming factor. It has a full length zippered, expandable gore that adds 3" to the girth.

With the expansion gore zipped open I can easily fit my WM Megalite down bag inside or my down quilt on top inside and still maintain the down bag's loft. This gives me a bag combo likely good to -40 F./C.

To me, though it adds weight, I feel all 0 F. or lower down bags should have shculd a zippered expandable gore as a safety item.

Good catch. I don't know where REI got the EN rating info for the Lamina 0 (or if it's accurate). Hmmm…

dave ,,,

assuming that there's no unobtanium … youll just have to go to the old school method of looking at the amount of fill in the bag, or the weight of the bag itself i guess

note that their temp rating could be construed as you sleeping in yr all clothes or using a VBL, as many do at those low temps … or it could be some brilliant idea from a marketing yuppie high on the latest sulawesi blend from sbucks

id assume that you need more than a base layer to be comfortable at those -20F and -40F temps for say the tundra and darkstar below … what i assume are the en ratings show a bit of a gap

Marmot has their 0degs EN tested (at least the Lithium)

Eric, good idea to compare fill weights. I graphed the fill weights vs temperature rating for the entire Lamina series, and it seems to make some sense – its somewhat exponential with larger increases in fill weight for each step getting colder.

“Marmot has their 0degs EN tested (at least the Lithium)”

According to some quick research, EN 13537 ratings can be applied down to -25C (-13F) comfort ratings. This document from Mountain Hardwear says that they apply EN 13537 ratings only to bags above 0F.

don t know about the winter bags but i have the lamina + 20 and at 25 deg one night i woke up sweating in it wearing just underwear and a t shirt for a base layer

divr6347

I have the -30, and IMHO, it would not keep one warm at -20, without sleeping in extra heavy clothing. I'm talking Mtn. Hardwear Chugah(spelling) pants, and a Patagonia Das Parka.
The 6'6" bag is oversized though, So its great to layer in, or like another mentioned, slip another bag inside. The only bag I would trust to its rating would be a WM or simular down bag, but then of course, the longer your out, the more the down bag will gradually begin to loose its loft.

The Lamina 20's and up seem to be reasonably accurate by all the accounts I've heard, but from what I've put together here and elsewhere, I'm thinking it would be appropriate to de-rate the Winter Lamina bags by about one step. There seems to be some EN ratings out there saying that the Lamina 0 is really only good to about 10F without additional warm clothes. So you might guess that the Lamina -15 would be good to around 0F, and then say that the Lamina -30 would be okay to -15F or so without adding a bunch of clothes.

I'm getting the impression that the winter Laminas are rated with the expectation that you'll be using a fair amount more clothing.

Just speculation.

I have a Lamina -15F in my possession that I'd like to use this winter, and as long as it can get me to 0F (-18C) before adding a lot of clothes that will be adequate.

Yeah, I'd say you'd easliy be good with the -15deg at zero degree weather. You can always add clothing and a hot Nalgene too, should things get a lttle colder!

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