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Outdoor Industry Association:New Industry Standard for Measuring Backpack Volume
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- This topic has 19 replies, 12 voices, and was last updated 6 years, 4 months ago by .
very timely.
I know this is a joke, but it would be really nice if there was a standard. I like the McHale method of measuring, but it seems like everyone does it slightly different.
@ Brad. Yes indeed. My first reaction at seeing the headline was “finally” then I saw the photograph….
There is a semi famous Australian / New Zealand set of packs The Mountain Mule and all its clones.
One of the reasons it was so popular was its ability to carry two full slabs of beer or 6 cartons of bulk red wine. Australia has used the beer standard for decades
Wouldn’t it be nice (cue: Beach Boys song).
Actually, I would be very much interested in any anecdotes on how people feel about certain manufacturers in terms of whether they think said manufacturer exaggerates their pack capacities, or is more conservative (i.e., packs holds More than the specs).
So packs are rated with collars not extended, and others rated with collars extended, and every pouch, pocket, and lid stuffed to the max.
ASTM already has a “Standard Test Method for Measurement of Backpack Capacity” ($44), yet pack volumes seem to be inconsistent between makers. Why? Could be problems with the standard, could be makers not following the standard for various reasons, could be marketing spin. Even with the weight of REI and MEC “enforcing” sleeping bag and pad ratings, some makers aren’t testing to those standards.
Independent testing to some standard would help, even if it used beer cans.
— Rex
Interesting – I didn’t know that.
FINALLY, a “meaningful standard”.
The old standard back-when was ping pong balls. Probably still the best.
Yes, ping pong balls can’t be 100% accurate but the discrepancy will be similar between packs (say compared to using water bags or mathematical formulas) and you can’t really mesure nor use some of the lost space in corners and folds anyway.
I just say ‘big enough to carry all my shit’
Ping-pong balls vs ASTM standard balls discussed here:
— Rex
However, some of the comments on the tombihn forum are … wrong (or ignorant). This often happens on the web.
>> The reason ping pong balls are not used is that they leave too much space between them.
Just wrong.
Explanation: the radius of the ball simply does not matter. The amount of dead space remains the same fraction of the total for ALL radii (for a large volume).
However, the comment that large balls make it harder to accurately measure the volume of a small pocket has some merit.
Random side comment. Consider a (small) box being filled with oranges, in layers. What layout or packing is going get the maximum number of oranges in it? This is a well-known packing problem, for which there is currently no mathematical solution. Really!
The problem is that the oranges are such a large size relative to the non-infinite box that edge effects are significant. Just thought someone might like to know.
Cheers
Edge effects for beers are even more significant! OTOH edge effects for some backpacking gear is pretty significant, so using smaller and smaller objects quickly stops making sense.
20 mm ASTM-standard balls almost seem like a reasonable choice. But 40 mm ping-pong balls are significantly cheaper.
As Roger has pointed out, some pack makers aren’t even close.
— Rex
When I did that review I priced the ASTM balls. They were outrageously expensive.
Cheers
First company to comply with new standards—even before they were written! Way to go, Seek Outside.

Looks as though there could be room for a bag of peanuts in there too.
Cheers
That’s not PBR. It might make a difference if it is drinkable.
They’re just gaming the system, designing pockets and packs around the measurement device. Cheaters!
— Rex
:-)
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