Air consumption?

[diveprof]

That's why a SAC rate is pretty much a piece of historical diving data. It represents the air consumption based upon one dive and one dive only.

But what a diver can do is take that historical data and apply it to an upcoming dive that presents the same characteristics of previous dives.

The thing about using the RMV is that one must take the time to calculate that during a dive. My computer tells me how much dive time I have on the tank given my CURRENT gas consumption. No need to do superfluous calculations.

In my basic opinion, one's SAC rate is, at best, a planning tool.

And, as Forrest Gump so eloquently stated, "That's all I got to say 'bout that."

Let's go diving.

the K

Kraken has it right.

Also, IMHO Worthington tanks rock -small, great characteristics.

 

[NAM001]

you cant use presure s a measure you have to use cu ft. otherwie you are saying you use less air on a 100 cf tank than a 80. enen my dive computer references in cf and mot lbs.

 

[NAM001]

With all due respect to the Kraken, Surface Air Consumption rate is reported in pounds per square inch per minute, while Respiratory Minute Volume is reported in cubic feet per minute. Substitute RMV for SAC in the above, and all is good. And as a good starting point, an average RMV is about 0.75 Ft³/minute.

you cant use lbs to measure sar it has to be cf otherwize you will be saying you less air on a 120cf tank than a 80. air consumption rate is not presure consumption rate

 

[M_Bipartitus]

Not entirely correct.....

True, both SAC and RMV have the same units (volume/unit time)...

psi is not a unit of volume, it's a pressure.

 

[dhuskins]

I would use one tank. After the dive, I would switch tanks and the remaining air is as good as wasted.

 

[Thalassamania]

While PSI is a pressure and cubic feet is a volume, if you hold the volume of the cylinder constant then they vary linearly and can be used quite interchangeably without confusion.

For example, if you have a cylinder that is 80 cubic feet at 3000 psi, does it really matter if you say that when it is half full, of when it is at 1500 PSI or when it is down to 40 cubic feet, are you saying anything different?

 

[Doc Harry]

While PSI is a pressure and cubic feet is a volume, if you hold the volume of the cylinder constant then they vary linearly and can be used quite interchangeably without confusion.

For example, if you have a cylinder that is 80 cubic feet at 3000 psi, does it really matter if you say that when it is half full, of when it is at 1500 PSI or when it is down to 40 cubic feet, are you saying anything different?

Mahalo nui loa.

Couldn't have said it better than you.