Calculating Gas Density

[Capt Jim Wyatt]

MultiDeco has gas density calculations as a tool with 2 different temperature settings

When you look at the two different temperatures does the density vary significantly?

 

[Deep Wreck Diver]

I'd say that's significant.

Of course I have no knowledge of the maths that is being used to generate these results

 

[lostsheep]

Of course I have no knowledge of the maths that is being used to generate these results


View attachment 892342 View attachment 892341

I suspect they are using the ideal gas law with:

[(PxV) / T ] being constant. T being in Kelvin (or Rankine)

 

[Capt Jim Wyatt]

Without any temperature adjustments I get 4.23 g/L.

I guess this is another example of things we do and believe that aren't always exactly accurate such as with OTUs and CNS%. But it is a guideline that is better than nothing.

 

[Deep Wreck Diver]

Absolutely, lots of people have dived with GD well above the recommended levels and survived. We all now understand that isn't a best practice though!

 

[Mobulai]

When you look at the two different temperatures does the density vary significantly?

Well it depends on the need to be exact to the nitty gritty and if there’s a need to account for extra adiabatic cooling

If I wanna think for example the Turbulence and need for a ReNr the Air/Gas density through a second stage in an OC dive, diving 21degC water/ambient might mean the air coming out is at 10-0 C so I’d lean towards a higher gas density; if I’m thinking about a warm humid gas in a rebreather loop I’d leave it at the lower destiny (or not concern myself much with it)
For these kind of very special cases the first online calculator I find generally just does the trick

Gas Density Calculator

This gas density calculator helps you find the type of gas based on the mass and volume entered.

www.omnicalculator.com

This one needs molecular mass but a quick search also helps out with that