A New Paradigm for Understanding Garment Warmth
Display Avatars Sort By:
Ashley Brown
(ashleyb) - F
Re: A New Paradigm for Understanding Garment Warmth on 02/23/2009 17:42:07 MST Print View

I'm not convinced that in the real world these figures really make sense however. And I'm always interested in what happens in practice.

Yep, fair enough. If it's your experience that a jacket placed over a bag is warmer than in it, then you can't argue with that. Whatever works best in practice is king. There may be something else going on in those situations you describe. Perhaps the down is not compressed evenly.

It would be interesting to hear from Richard whether he has tested it on a real sleeping bag. Here's some data he posted in one of those threads, but I'm not sure where he got it from. Note the clo/kg of down doesn't change as you increase the fill:

sleeping bag overfill clo chart

Edited by ashleyb on 02/23/2009 17:43:28 MST.

Adrian B
(adrianb) - MLife

Locale: Auckland, New Zealand
Re: Re: A New Paradigm for Understanding Garment Warmth on 02/23/2009 17:50:50 MST Print View

"If it's your experience that a jacket placed over a bag is warmer than in it"

One factor is that the jacket will be compressed underneath you when worn, not when placed over you. But this might not be significant, and perhaps countering this is that I find it hard to get all of a jacket usefully covering me without wearing it.

And of course it's not a factor in a too-tight bivy bag situation, where Chris still observed the lesser-compressed bag being warmer.

Lynn Tramper
(retropump) - F

Locale: The Antipodes of La Coruna
Re: Re: A New Paradigm for Understanding Garment Warmth on 02/23/2009 17:52:12 MST Print View

>I would say that the amount of down fill (assuming same quality) is probably the best approximate and simple measure of a garment's warmth.

I thought this was a generally accepted principle of insulation design. The more fill=the heavier insulation=warmer bag. But all most of us need to know is what is the (accurate) warmth rating of the bag compared to it's weight? I choose WM bags because, *underfilled* or not, I find their comfort rating to be accurate and their bags to be light.

Chris Townsend
(Christownsend) - MLife

Locale: Cairngorms National Park
A New Paradigm for Understanding Garment Warmth on 02/23/2009 17:56:26 MST Print View

Of course the problem with real world experiences is that there's always something else going on! Any anecdotal statement is always missing some factors. However it is in the real world that bags and jackets are used to keep warm.

Those figures are interesting. I'd like to know where they came from. 12oz is a significant amount of down.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Re: A New Paradigm for Understanding Garment Warmth on 02/23/2009 23:52:25 MST Print View

Bob (Dennis-Your question is incorporated in the last paragraph)

I have been up in the Sierras for a few days and am now just getting an opportunity to start responding to questions. First I want to say I was very impressed with your responses to Will's article on "Salomon Tundra Mid WP Insulated Boot Review". Your posts were courteous, well structured, and compelling in the support of your position... great job.

You said, "Can you tell us more about what makes for a better rating"? The fleece and synthetic insulation vendor's clo/oz ratings closely correlated with their relative performance vis-à-vis one another. The down insulation results closely correlated with the down fill amount. All insulations do a good job of blocking convection. Blocking radiation losses is the biggest variable between the synthetic insulation types and as well as the impact of down density. Based on my tests, fleece and synthetic specifications appear to be based on the inclusion of a still air layer on the outside of the insulation in addition to the insulation itself. When layering garments, frequently this still air layer won’t be present and the ensembles won’t be as warm as you would anticipate. Sizing of each layer to have at least a 6mm gap between them is necessary to approach the insulation vendor’s published clo/oz values.

You said, “When a manufacturer comes out with a "new and improved" version next year, how do we know whether or not it still occupies the same place in your table? And if not, then where it belongs?” The situation with garments and sleeping bags in the US is the same as it was with sleeping bags in Europe prior to the EN 13537 standard. In other words the consumers aren’t provided adequate information to make an intelligent decision. I suggest buying from vendors who have a reputation for honest representation of their products specifications and then try and find the closest match to something which has already been independently tested by multiple sources. It is in the interest of most manufactures and their advertising partners to use FUD (fear, uncertainty, and doubt) to discredit the value of independent testing. The only manufacturers who would benefit from having independent tests published are the one who products test best.

You said, “How do I determine where a garment not in your table fits in?” You can extrapolate from the existing test results. For example, in a post subsequent to yours, Dennis Park asked, “By any chance, would you know where Mountain Hardware's Compressor men's jacket would fit on your chart? Oops, forgot to mention 2007 model.” The 2007 Compressor specs were size medium [Weight] 16 oz [Shell] Superlight 15D, [Insulation] PrimaLoft One 115 g/m2. That is the same insulation type and a similar amount to what was used in the WT PL1 hoody that I tested. The Wild Things Primaloft One hoody used 2 layers of 60 g/m2. This jacket would theoretically test out with an intrinsic clo of approximately ~1.46. In other words, it is ~1.5 times warmer than a Polartec 300 weight or a Patagonia Micropuff pullover or jacket.

Edited by richard295 on 02/24/2009 17:48:16 MST.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Re: A New Paradigm for Understanding Garment Warmth on 02/24/2009 00:01:11 MST Print View

Ashley,

Thank you for the kind words. I guess that the first time I looked at the question of 300 weight fleece versus the Montbell Light Alpine question; I interpreted vendor specs to arrive at a conclusion... sorry if I screwed up the first time. This time around I actually tested each of the products myself.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Re: A New Paradigm for Understanding Garment Warmth on 02/24/2009 00:16:50 MST Print View

Huzefa,

I used a guarded heat plate. It measures the cumulative heat conductivity from all modes of transmission (conduction, convection, and radiation). The measurement technique integrates the measurements in the seam, along the ramp up/down, and max loft area.

The average clo was 6.18 divided by 1.5 inches for a less remarkable value of 4.12 per inch. A stack of cotton cloth yields 4 clo per inch and so the warmth is less of an anomaly than is the clo/oz.

The Fugu failed in the market place and is no longer available. I don't think people appreciated the jacket's extraordinary value proposition because New Balance wasn't a known performance jacket vendor in the UL community.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Question on 02/24/2009 00:22:13 MST Print View

Brad,

Yes the Patagonia Polarguard Delta 2.7 oz/yd2 Pullover is the previous version. The current version uses 3-oz Climashield® Green continuous filament polyester (40% recycled).

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: good chart on 02/24/2009 00:28:17 MST Print View

Brett,

I haven't measured those garments but my GUESS concurs with your assessment.

Huzefa Siamwala
(huzefa) - M
Re: Re: Re: A New Paradigm for Understanding Garment Warmth on 02/24/2009 00:34:20 MST Print View

I think you missed my point.

Here is a quote from an old post of yours -"The Fugu down jacket is 800 fill and the Cabelas down jacket is 650 fill. They are sewn through construction. 1 1/2" is the maximum loft. The baffles average 5" wide. Only approximately 2" of the 5" is at the maximum loft. 1 1/2" on either side it ramps up from a few mm to 1 1/2". My crude estimate is that the average loft is about 70% of the max or 1.05"

clo at max loft = 6.18
average loft = 70% or 1.05"
average clo = 70% or 4.362

Wouldnt you consider average clo as the effective clo value of the garment?

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Re: A New Paradigm for Understanding Garment Warmth on 02/24/2009 01:27:17 MST Print View

Michael,

Thanks for the positive words. You said, "How does Polartec's own "thermal pro" compare to Polartec's traditional fleece at the same fabric weight?" I haven't tested it to verify their claims but their specs claim, Polartec 300 = .007 TOGS g/m2, Thermal Pro #4060 = .010 TOG g/m2, and Thermal Pro #4082 = .011 TOG g/m2.

Miguel Arboleda
(butuki) - MLife

Locale: Kanto Plain, Japan
Re: A New Paradigm for Understanding Garment Warmth on 02/24/2009 01:37:06 MST Print View

I've always wondered why people don't also consider the heat sink effect of different materials in clothing. In buildings the R-value of a material can affect the temperature sensation of a room; even though the air in the room may be the same temperature, the materials used in the walls and the floor, when touched, can make the room feel cold or hot. That's why, on a cold day, rooms with wooden walls and floors tend to feel warmer than rooms with stone walls and floors. Some of the jackets that I have when I touch the outer nylon fabric feel much colder to the touch than others. There must be some effect of this heat sink sensation on the outer fabric, contributing to the overall feel of the warmth of the jackets.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Re: Re: A New Paradigm for Understanding Garment Warmth on 02/24/2009 09:10:19 MST Print View

Michael,

After waking up this morning, I thought about my response to your question about how Thermal Pro compares to Polartec 300 question some more. I think there is a clearer way to answer it. It is apparently frequently asked because it is one of the Thermal Pro FAQs: What is the difference between Polartec® Classic and Polartec® Thermal Pro®?

"...We have specific thermal data on each Polartec® Thermal Pro® fabric but without knowing which Polartec® Thermal Pro® fabric you are considering, it is impossible to rate it against Polartec® Classic 200 or Polartec® Classic 300. Each Polartec® Thermal Pro® fabric is developed to meet the expected functions needed for a specific use."

I think the clearest answer is that they specify both Polartec 300 and Polartec Pro at .16 clo/oz/yd2. Polartec 300 is 10.9 oz/yd2. Common Thermal Pro fabric options are 6.9 oz/yd2, 7.1 oz/yd2, and 9.4 oz/yd2. To compare their loftiest Thermal Pro version to Polartec 300 multiply both fabric clo/oz by .16. Comparing the ratio yields 14% less warmth for the thickest version of Polartec Pro. It is a much loftier and compressible fabric and so it LOOKS MUCH WARMER and compresses much better for stuffing in a back pack. I haven’t tested any Thermal Pro garments and so this is theory only.

Edited by richard295 on 02/24/2009 09:11:00 MST.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Re: A New Paradigm for Understanding Garment Warmth on 02/24/2009 10:04:54 MST Print View

Tom,

I haven't tested the insulation of Under Amour’s products because they fall primarily into the category of base layers and it is very difficult to get an accurate measurement of insulation that thin. Base layer insulation tends to be of less importance than that of most clothing items, its tactile properties, and the way in which it handles moisture, are of much greater concern since it is in direct contact with the skin.

It is really difficult to get an accurate measurement of base layer insulation based on standards procedures. The usual American Society of Testing Materials (ASTM) method for thickness measurement requires compressing the material by 0.7 g/cm2 (.01 psi). This very mild level of compression is still sufficient to compress the fibrils at the surface of the material and these, although very compressible, do contribute to trapping additional surface air film thickness. If one uses a method where thickness is measured without any compression the measured intrinsic insulation will approximate the insulation predicted using 1.57 clo per centimeter (4 clo per inch).

The insulation of base layers is seldom a major consideration in thermal comfort, since it lies within an already trapped still-air layer between the skin and the outerwear. Indeed, static copper manikin measurements of a clothing system frequently give the same insulation measurement with or without a base layer. Nevertheless, a thicker base layer will contribute warmth in the presence of wind or body motion, particularly if the outerwear is not totally windproof, the closures are not tight, or the clothing is compressed by the weight of outer clothing layers or back pack.

A base layer’s insulation over the torso will generally be close to that approximated from its full uncompressed thickness. This is because of the air gaps between the underwear and the clothing worn over the torso. However, the insulation over the arms and the legs will be closer to that suggested by the compressed (ASTM) thickness measurement as a result of the closer fit of the outer garments.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Micro Puff on 02/24/2009 10:18:04 MST Print View

Jonathon,

I haven't tested any Climashield Green garments but Polarguard Delta is specified at 3.06 clo/inch and Climashield Green is specified at 3.25 clo/inch. We can view them as equivalent.

40% of the Climashield Green fibers are recycled polyester and they have to be thicker than virgin fiber for the same strength. This is why Green is much less thermally efficient than XP.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: fugu really that warm? on 02/24/2009 11:41:21 MST Print View

Michael F.,

The garment's torso is tested with a guarded hot plate to ascertain its insulation value. I tested a Patagonia down Sweater vest and determined its intrinsic clo was ~2.31. I also tested a Patagonia down Sweater Pullover hoody and determined its intrinsic clo was ~2.31. The insulation, fabric, and construction although slightly different between the garment types, yielded the same ~intrinsic insulation value. Total clo, for each garment, is determined by multiplying the intrinsic clo by the body surface area that it covers. The average body surface areas (BSA) covered by different garment types are as follows:

Hat 4%
Shoes 7%
Balaclava 8%
Pants 43%
Shirt or Jacket 48%
Hoody 54.5%
One Piece Suit 80%
Sleeping Bag 98%

If you want to compare the total clo between two dissimilar garment types (for example the Fugu jacket and the Permafrost Parka), multiply the intrinsic clo value times the BSA for each garment to determine how they compare. The Fugu total clo is .48 * 6.18 = 2.97. The Permafrost total clo is .55 * 5.24 = 2.90. The hood on the Permafrost is huge but a down balaclava, in combination with the Fugu would easily beat it for greater warmth at less weight, save the relative durability issue.

My objective for this thread was to provide a very simple way to understand the relative warmth of different types of garment’s insulation. It was not to provide the total clo value for each different garment type and insulation type. None the less, for any body so interested, the above BSA values allow you to calculate ~total clo.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Powerstretch on 02/24/2009 12:00:23 MST Print View

Adrian,

Thanks for the kind words. The Power Dry and Power Stretch garments are hybrid base layers/insulation layers. They need the stretch fibers to facilitate the base layer functionality only. For use on trips like Erin and Hig's coastal hiking/packrafting adventure the material gets good reviews. It is probably too heavy and warm for most UL backpacking applications.

Tom Kirchner
(ouzel) - MLife

Locale: Pacific Northwest/Sierra
Re: Re: Re: A New Paradigm for Understanding Garment Warmth on 02/24/2009 12:15:40 MST Print View

"Tom,

I haven't tested the insulation of Under Amour’s products because they fall primarily into the category of base layers and it is very difficult to get an accurate measurement of insulation that thin."

Richard,
Many thanks for the information. I am in the process of trying to further reduce the the clothing component of my base weight, and you have likely saved me considerable time and expense. Your insights are always appreciated.
Best regards,
Tom

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Re: A New Paradigm for Understanding Garment Warmth on 02/24/2009 12:19:17 MST Print View

Tom and Huzefa,

Please post a link to your article after it is published. Particularly in the realm of WPB fabrics you have provided many well researched posts. I have no doubt that your article will be of similar quality.

Comparing options without making things too complicated was indeed the objective of the graph and this thread.

Huzefa - In line with those objectives, I hope that you understand that old forum posts that went into a much higher level of technical detail won't be discussed by me in this thread.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Re: RE: A New Paradigm for Understanding Garment Warmth on 02/24/2009 12:24:39 MST Print View

Lynn,

Thanks for the kind words. I have been contacted by a forum member in the Bay Area. He will provide a WM jacket and vest. I will add this info. If someone in the Bay area has a Nunatak Skaha to loan for a test, I will also add that info.