Frustrations regarding conversions

[theslyfox01]

Hi everyone I was just struggling though reading a page on scuba tanks with all the refrences to tanks that are x cubic feet, or x litres, as well as however many psi air pressure people begin there safety stop on, etc, etc, in Australia we use BAR for our SPG's, DIN valves are all over and as for tank sizes.. I have no idea I see refrences when I'm looking to buy tanks that are 3 Litre ponies, and then sometimes they will refer to the usual tanks as 88 cubic footers, is there someone with a clue on a place where i can find a table with all this stuff in a comparison chart so I know exactly whats what it would save my headache

PS I was just looking at ponies for sale online, and I had to have a good laugh at the 9 cubic feet pony for sale, whats the deal there? Surely a pony that size has no practical use whatsoever, unless you run out of air, your buddy is 2 metres away from you and you want 2 breaths of air to breath on your way to chasing him down and grabbing his octopus

thanks for any clues

 

[Scubaroo]

theslyfox01 once bubbled...
Hi everyone I was just struggling though reading a page on scuba tanks with all the refrences to tanks that are x cubic feet, or x litres, as well as however many psi air pressure people begin there safety stop on, etc, etc, in Australia we use BAR for our SPG's, DIN valves are all over and as for tank sizes.. I have no idea I see refrences when I'm looking to buy tanks that are 3 Litre ponies, and then sometimes they will refer to the usual tanks as 88 cubic footers, is there someone with a clue on a place where i can find a table with all this stuff in a comparison chart so I know exactly whats what it would save my headache

PS I was just looking at ponies for sale online, and I had to have a good laugh at the 9 cubic feet pony for sale, whats the deal there? Surely a pony that size has no practical use whatsoever, unless you run out of air, your buddy is 2 metres away from you and you want 2 breaths of air to breath on your way to chasing him down and grabbing his octopus

thanks for any clues

9cf is a decent amount of air - it's the 1.7cf Spare Airs that are scary.

In the metric world of tanks, tanks are measured by water capacity - eg 10L is a common size, and a working presure is given - eg 232 bar. This tank would hold 10 * 232 = 2320L of air, at ambient pressure sea level (or near enough). There is approximately 28.317L per cubic foot, so 2320 / 28.317 = 81.9cf. These figures are just an example.

A *rough* rule of thumb for conversion is a 10L tank is 80cf, and a 12L tank is 100cf.

 

[MikeS]

Slyfox,

Check out Martin's divetime calculator this may help you understand the differences between the metric and imperial specifications.

IMHO a 9 cubic foot tank is not useful as a breathing gas tank, but they are used to hold argon for drysuit diving.

Mike

 

[theslyfox01]

Thanks guys for helping me out on that one