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BlizzardBag; Richard N. help with Togs
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Home › Forums › Gear Forums › Gear (General) › BlizzardBag; Richard N. help with Togs
- This topic has 20 replies, 11 voices, and was last updated 6 years, 4 months ago by Andrew Shapira.
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Nov 25, 2007 at 5:28 pm #1225979
Richard, or anyone else who wants to take a stab at this..
This company is claiming their foil bag has more than twice the insulation/weight ratio of goose down. (They mistakenly call it "warmth/weight")
http://www.blizzardsurvival.com/page.php?xPage=reflexcell-warmth.html
Is this remotely posssible?
I assume they tested a stationary bag, where no inter-layer air venting occurs. In a real down bag airflow is limited by the down; this foil burrito would seemingly have no such limiting factors.
Im thinking of replacing my Adventure Medical bag I carry on day hikes with the small (320g) one of these; but Ill wait to hear some educated opinions first. Thanks in advance.
Nov 25, 2007 at 8:40 pm #1410171Brett,
For a comparable insulated bag such as the Mont-bell SS DH #5, my (1.8x rounded up) calculation indicates their 2x claim is feasible.
For UL backpacking, a Momentum / 800 fill down quilt will yield close to equivalent ratio and a bag such as the Western Mountaineering LineLite yields only a slightly higher ratio when the mandatory vacuum packing is factored in. The vacuum packaging has to be carried with the Blizzard bag to keep the volume from increasing dramatically and it weighs .9 oz.
For its intended emergency use application it is an excellent product. I occasionally carry one as does Mike Martin.
Nov 26, 2007 at 6:00 am #1410184Where does the clo number on the blizzard bag come from? I've seen this talked about before here but maybe I'll grab one to play with?
Nov 26, 2007 at 8:15 am #1410193Christopher,
The Blizzard bag's Tog value was measured using a manikin test conducted by Leeds University. Tog is a measure of thermal resistance as is clo; so, I just converted their Tog value to the equivalent clo value for comparison with two sleeping bags common to the UL backpacking community.
I also cut up a Blizzard bag to analyze its construction. The bag's materials, construction methods, and my resultant thermal physics calculations approximated the Leeds TOG value.
Remember that, like the sleeping bags, the Blizzard needs ground insulation ~ equal to a Thermarest Standard to achieve the sleep system insulation values in my table.
Nov 26, 2007 at 8:33 am #1410195Thanks Richard, just the info I was after. How is the insulation/constuction they are using achieving such a high insulating value compared to a traditional sleeping bag?
Nov 26, 2007 at 9:22 am #1410198Are these bags breathable or do they act as a vapor barrier? Can you pack them up again reasonably small to use for multiday trips?
Nov 26, 2007 at 10:06 am #1410204>> Are these bags breathable or do they act as a vapor barrier? Can you pack them up again reasonably small to use for multiday trips?
Hi Guys-
The outer layer is completely impermeable and waterproof (unless it is torn — it is very fragile material, sort of like a space blanket). But, the inner layer is perforated. So, the theory goes that moisture will pass through the inner layer and condense somewhere in the honeycomb of layers. IMO, this is an excellent design for emergency use as it allows you to wear your insulated clothing inside without its loft degrading from moisture as it would if the inner layer were a VB. But, unless you could turn it inside-out and dry it during the the day, it would likely accumulate moisture over successive nights of use.
Once you open the vacuum packed brick, it will never again be able to be packed as small. But, nevertheless, it still packs reasonably small.
I use mine primarily for backcountry ski day trips. With my insulated clothing it should (hopefully) keep me warm "enough" down to freezing if I have an unplanned night out. With a candle in a hasty snowcave, or small campfire, that should (hopefully, again) be sufficient to survive.
Cheers,
-Mike
Nov 26, 2007 at 10:23 am #1410205Christopher,
As a cell size increases, air moves from conduction flow, to laminar flow, to convection flow. They licensed the Mont-bell SS patent and applied it in a unique way so that they keep the each internal cell size just below the limit where laminar flow starts. They addressed radiant heat losses by using two reflective surfaces. They addressed the condensation issue by using perforations to move the moisture away from the body.
Nov 26, 2007 at 10:28 am #1410207Ian,
I agree with Mike's answer realtive to your vapor barrier question.
Regarding your question about repackaging the bag… it will require a compression sack to get it near the size of down bag after removing it from its vacum packaging.
Nov 26, 2007 at 10:52 am #1410212Is the 385g listed on the blizzard bag website complete with packaging and what you listed in that chart?
Nov 26, 2007 at 10:59 am #1410213Christopher,
On my postal scale, a vacum packaged Blizzard Bag weighs 12.5 oz (354 g).
Nov 26, 2007 at 4:34 pm #1410252Which is better, insulated clothing plus a Blizzard Bag, or insulated clothing plus a BPL Nano bivy sack?
Nov 26, 2007 at 4:43 pm #1410254Robert – If you aren't carrying a sleeping bag, the Blizzard bag is better because it provides both the bivy function and the sleeping bag insulation function.
If you are carrying a sleeping bag, the BPL Nano bivy sack is better because of its much superior durability, smaller volume requirement, and lighter weight.
Nov 26, 2007 at 5:26 pm #1410261This thread has been very informative. I'm going to replace the mylar bag in my day hike kit with the small Blizzard bag.
Nov 26, 2007 at 6:23 pm #1410265This is a very interesting bag. Is it intended strictly for emergency use? or could it be used for summer backpacking? Has anyone used it for extended periods of time?
Nov 26, 2007 at 9:26 pm #1410294this guy loves these things, he also talks about turning it inside out during the night because of the moisture.
Nov 27, 2007 at 6:57 am #1410317Kevin,
Is it intended strictly for emergency use.
Nov 27, 2007 at 7:06 am #1410319and it's annoyingly noisy to sleep in as a mate of mine can tell you.
Nov 27, 2007 at 8:41 pm #1410403Richard, thank you. I will extrapolate from your answer that if I have strictly emergency clothing such as micro-puff pants, and a micro-puff pullover, plus a Nano bivy, plus rain gear, I will have the best of both worlds, able to stay warm as I walk out in a freezing blizzard, and also able to survive a night if I am immobilized.
Feb 9, 2010 at 11:07 am #1571646Does anyone know a good place to purchase a Blizzard bag here in the states? I've heard of people being scammed by US companies claiming to sell them but the product itself looks really tip-top…
Thanks!
Nov 13, 2017 at 9:50 am #3501833An old thread, but maybe a good place to relay some info – I took my Blizzard bag out of its packing, and wrapped it tightly with Saran Wrap and two rubber bands. When I did this, I measured how much weight this saved. think it was around an ounce, but don’t recall the exact number. The bag seems to be holding its shape after a few outings and then a few months of sitting on my shelf while I experimented with taking a different emergency setup. I may get a Blizzard Bag light and try the same thing.
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