Cave fill final gas volume

[Lorenzoid]

I'm starting to regret opening this can of worm... Just wanted to know how much air I got in my tank, man.

No need to regret. The key would have been to have clarified whether you are addressing the question to a cave diver or to a physicist.

 

[kierentec]

I'm starting to regret opening this can of worm... Just wanted to know how much air I got in my tank, man.

Tank factors are the approximate volume of gas per 100psi. So:

3500psi/100x3(tank factor for a single LP85 or HP100)= ~ 105cuft
Close enough for what we’re doing

 

[JMarc]

We went to the moon using Imperial, works just fine.

Excepted that the project was also using metric units. For instance, IIRC, the computer used on the landing module was doing its computation in metric and used imperial units only when communicating with humans.

 

[J-Vo]

Calculate with the GERG formula:

 

[Manatee Diver]

Why don't y'all just agree to switch to metric?

Because that doesn't account for Z factor either.

 

[Whitrzac]

All these posts are only valid for air/nitrox. Helium has a different z factor that can make a bigger difference.

 

[Capt Jim Wyatt]

The practical way to determine gas volume starts by determining the tank baseline.
The way you do that is in This Document-- All the rest of this Z-factor crapola purely academic and as @kierentec stated is not needed for REAL WORLD gas planning.

 

[Lorenzoid]

@J-Vo , is there an app for that? That looks really easy to use.

 

[lunaire]

Calculate with the GERG formula:View attachment 801336View attachment 801337

I made a whole excel worksheet to calculate, and now you're showing me an app that does it with fancy graphics/tables? And without giving the source??

 

[kensuf]

OMG you guys are making this too complicated.

Look it's simple. 104's are 10% more than 95s and 20% more than 85s. So if a person is in 85s and they have 3600 PSI, meaning they can use 1200 PSI for penetration in an ideal scenario (3 person team), a guy in 104s diving in that team can only use 1000psi. Yes, yes, yes, I know it's really more like 972 PSI, but in a 3 person team that small negligible amount won't matter.

Is someone diving 80s? Then you guys are probably in Mexico. Go get tacos after.