Average Gas Consumption

[Thombalabomba]

Al80

How much air volume it can hold at working pressure. It is actually not 80cuft, it is 77.4cuft. AL80 is 11L<AL80 <12L

Alright thanks for your response!

I was just in bonaire for 2 weeks where the standard tank everywhere is referred to as 12L aluminium and i've had them filled between 195 and 215 bar with 200 on average when taken off the pile, so a bit of a hassle to figure out if this is the same tank as the al80 that's generally mentioned.

 

[BoltSnap]

Al80
Alright thanks for your response!

I was just in bonaire for 2 weeks where the standard tank everywhere is referred to as 12L aluminium and i've had them filled between 195 and 215 bar with 200 on average when taken off the pile, so a bit of a hassle to figure out if this is the same tank as the al80 that's generally mentioned.

It is a "convention" to call it 12L since it is just a little bit less than 12L and in the US call it 80cuft since it is very close to 80 but not exactly.

 

[inquis]

does an AL80 refer to the amount of surface pressure air it can hold at max pressure

Yes, all the US tanks go by "capacity", the amount of air contained (starting at rated pressure) if released to 1 atm. An AL80 cylinder has a volume of 11.1 liters. The Ideal capacity is 80.1 cuft, but due to the non-ideal nature of air at the rated pressure, it winds up only being 77.4 cuft. (Some other types are named by the real capacity; an HP100 for example, has a real capacity of about 100 cuft.)

(The non-ideal nature impacts the metric picture as well. Ideally it would hold 11.1 liters*207 bar = 2298 liters at 1 bar. It winds up being about 2192 liters, again from non-ideal compressive effects.)

 

[scubadada]

It is a "convention" to call it 12L since it is just a little bit less than 12L and in the US call it 80cuft since it is very close to 80 but not exactly.

Is the AL cylinder we use on liveaboards outside the US the same as the ubiquitous AL80 (77.4)? My calculations for metric volume seem to be off. Could someone set me straight please?

77.4 cu ft x 28.32 liters/cu ft = 2192 liters

2192 liters/207 bar = 10.6 liters/bar

Edit: Thanks to @inquisit for the post while I was typing

 

[MT_Shadow]

Average depth, not bottom depth.

ah I dont have average depth logged unfortunately

 

[tursiops]

ah I dont have average depth logged unfortunately

Are you using a computer? Some log average depth in their own log, which you can access after the fact, for at least the last 20 dives or so.

 

[MT_Shadow]

Are you using a computer? Some log average depth in their own log, which you can access after the fact, for at least the last 20 dives or so.

hmm my dives would be scattered across 3 computers and I am not sure if the data would still be there after updates and such. I always log info off to my logbook after the day is done... but i have been keeping data for dive tables type calculations from back when i started. I should start keeping average depth in there i guess. I am switching to the perdix with AI though now so I can track consumption rates and stuff too now.

 

[scubadada]

Just 12 days since the last summary. Another 1000 views, now over 36,000. Another 16 votes in the poll, now 612,

The median, mode, and weighted average are all 0.5-0.59 cu ft/min or 14.2-16.7 liters/min

If you have not voted in the poll, please consider doing so. If your average RMV has changed, please change your vote.

Happy new year, good diving to all

 

[dumpsterpurrs]

Happy to report over the course of 10 months I've moved from the third bracket (0.4-0.49 cu ft/min) to the first one during fun dives (consistently .23-.3 cu ft/min) and the second bracket during working dives (.3-.34 cu ft/min guiding or cleaning reef in strong currents). This survey has helped provide me with a structure to work on my air consumption. As I continue to battle worsening chronic illnesses, some of which make my heart beat a lot faster than it used to, I'm not sure if I can ever improve these stats, but it's been a fun journey and I've come to understand my body a lot more.

 

[scubadada]

Hi @dumpsterpurrs

That's a nice story. Very few divers achieve such low gas consumption.

Best of luck with your diving and your health.