Math Question
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Do all calculated estimates in cubic feet and tank pressure will not matter other than in determining your total available gas.
SkimFisher
Contributor
Rock Bottom and Gas Management for Recreational Divers
Good read.
...also, what he said. Read up on "gas matching". Although, in a recreational setting you typically will be diving with other divers using AL80's - which means you'll be turning according to THEIR limits.
Another good read (you may actually want to start here):
http://www.tdconline.com/articles/psicuft.html
Good read.
...also, what he said. Read up on "gas matching". Although, in a recreational setting you typically will be diving with other divers using AL80's - which means you'll be turning according to THEIR limits.
Another good read (you may actually want to start here):
http://www.tdconline.com/articles/psicuft.html
Bogie
Contributor
SkimFisher that was a very good article. Thanks.
SkimFisher
Contributor
No prob 
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Yes,skimfisher that was excellent, great info.
StreetDoctor
Contributor
In this instance the ratio formula works well because you KNOW that the AL80 carries less volume. If you are unsure you cannot use this method.
First thing you need to do is get the tank factors: 77.4 (cubic feet)/3000 (rated pressure) = .025 for the AL80
LP120= 120/2640= 0.045
.025/.045 = .55 This means the AL80 contains approx. 55% of the volume of the 120.
Take your useable gas for your smaller tank, for example I'll use 1000psi in the AL80. (Your minimum gas is 2000psi)
Now multiply that number by the above formula. Round for conservatism
1000x.55 = 550 psi in the larger tank or 500.
Turn pressure AL80 (rated 3000psi)= 2000
Turn pressure LP120 (rated 2640psi)= 2200
SkimFisher
Contributor
I will say this - LP120's are huge (but I don't know how big of a guy you are). You might want to look at HP120's instead. They are about the size of AL80's. I had never seen one up until a few weeks ago and was quite impressed.
Of course, you'll need DIN regs for that. But most LP tanks come with DIN valves anyways so it may be worth it to make the switch now. I recently purchased some LP tanks and found it worth while to just switch my reg over to DIN. I prefer to not have to deal with the yoke inserts.
Of course, you'll need DIN regs for that. But most LP tanks come with DIN valves anyways so it may be worth it to make the switch now. I recently purchased some LP tanks and found it worth while to just switch my reg over to DIN. I prefer to not have to deal with the yoke inserts.
StreetDoctor
Contributor
FWIW I have and use a yoke valve on my HP130 ALL the time without any problems. I believe this has been discussed here before.
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