SAC vs RMV, revisited

[Storker]

liters/minute

Which liters? Real liters at depth, or recalculated to surface liters?

Yeah, I know. I'm kinda nitpicking here. But one liter at 30m is 4x the amount of gas as one liter at the surface.

 

[Manatee Diver]

The proper units are "liters per minute per atmosphere" or "cubic feet per minute per atmosphere."

 

[Storker]

The proper units are "liters per minute per atmosphere" or "cubic feet per minute per atmosphere."

Or "surface liters per minute", AKA SLM

 

[Manatee Diver]

Or "surface liters per minute", AKA SLM

This is without making up my own term. It isn't unusual to have complex units. IIRC half of the chemistry exams I took was converting things until you get it into the desired units and solving the question. The other half was memorizing stupid stuff, that made no sense to memorize.

 

[Storker]

chemistry [...] stupid stuff

Hey! I resemble that remark!

 

[scubadada]

So... if you simply give the units for the gas consumption, you don't have to call it anything. just say it is psi/min or bar/min OR cu ft/min or L/min

My 10 1/2 year old Oceanic VT3 gives me both my SAC in psi/min and RMV in cu ft/min. My 1 1/2 year old Teric only gives me SAC in psi/min, I have to calculate the RMV with the tank factor in cu ft/psi.

 

[scubadada]

This is without making up my own term. It isn't unusual to have complex units. IIRC half of the chemistry exams I took was converting things until you get it into the desired units and solving the question. The other half was memorizing stupid stuff, that made no sense to memorize.

Ha, I got through my 2 quarters of upper division physical chemistry mostly through dimensional analysis, it's a different kind of skill, works for lots of stuff

 

[Manatee Diver]

Ha, I got through my 2 quarters of upper division physical chemistry mostly through dimensional analysis, it's a different kind of skill, works for lots of stuff

My ability to do math and convert units was the only thing that allowed me to survive Gen Chem 1 and 2. The calculation section would be 100% perfect, and the rest would just be derp. Do quantum spins matter if you are a CS major?

 

[tursiops]

Damn near anything is better than saying "my air consumption is 20."
At the very least, say whether you mean at the surface or at depth, and do you mean based on pressure or volume.
And if you then say, "at the surface, based on pressure," then I still have to ask "what size cylinder?" and "are you working in imperial or metric?"
Otherwise, your '20" in meaningless.

 

[Kensei]

See Post #1 min this thread. There is no agreement.

So what you're saying is that we have:

1. A formula that calculates pressure/minute consumed and varies based on tank characteristics

2. A formula that calculates volume/minute consumed and is not impacted by tank characteristics

Neither formula has a name commonly used in the dive industry, hence, terms like SAC, RMV, etc. may be used interchangeably for either formula above?