volume measurement

A common way of doing it has been to use polystyrene balls.
Fill the pack, transfer them to a box, work out the volume from that.

Yeah, but polystyrene is compressible.
The balls and the cylinder I just got are following the standard method ASTM F2153.

—
Jangtian Shieh(Syoten)
HANCHOR outdoor gear design Co. Ltd.

Have fun nerding out.

will the balls pack a little? Like, if you shook them, they'de settle a little, getting closer to the maximum number of balls you could fit into a volume? Maybe you could put them on a vibration table.

(Probably insignificant, I'm just "nerding out")

Cool stuff. I'd trust your volume calcs more than most other numbers I've seen.

I used water to estimate volume once. Wasn't worth repeating. I put a large garbage sack in the pack first to prevent leakage. It was a lot of work, heavy and a mess.

Very good stuff!

I found that most European mfrs were very honest about their volumes, but some (not all) USA mfrs were blatantly dishonest and quoted seriously excessive volumes. There IS an American Standard for pack volume measurement, but a few American mfrs deliberately violated the Standard and made what I regard as fraudulent claims.

See our reviews:
http://www.backpackinglight.com/cgi-bin/backpackinglight/lw_internal_frame_packs_part_1a.html
http://www.backpackinglight.com/cgi-bin/backpackinglight/lw_internal_frame_packs_part_1b.html
http://www.backpackinglight.com/cgi-bin/backpackinglight/lw_internal_frame_packs_part_1c.html
http://www.backpackinglight.com/cgi-bin/backpackinglight/lw_internal_frame_packs_part_2.html

Cheers

@Jerry,
I indeed need to shake the pack when filling the balls.
This is not a big problem for a drawstring or roll-top top-loading backpack. But it takes more time to measure packs with a lot of zipper pockets. It's just difficult to fill and I feels there is always some room for several more balls.

@Daryl,
I haven't tried to measure a pack with water, but I can imagine how difficult it is.

@Roger,
Great reviews!

I don't know if others intentionally list excessive volume, but I would think they just don't have proper tools to measure. For me, it was really difficult to calculate the volume without proper equipment. I was afraid that I might be cheating if my calculations are larger than actual volume. I was also afraid that my calculations are too small making the spec. of my packs look small or heavier than others.

Now I can finally update more reliable volume measurements of all the products in the near future.

—
Jangtian Shieh(Syoten)
HANCHOR outdoor gear design Co. Ltd.