LP TANKS

[rjack321]

So if i'm filling lp steels to 3500 with 18/45 versus something like 12/65 it's not the same gas volume? How would you calculate the gas volume?

For exactly the same pressure it's not the same volume. And worse it's not linear.

Here are some resources on z-factors. I dont know of a software to do this for scuba mixes sadly.

Calculating SCUBA Cylinder Capacity | Dive Gear Express®

Or why does my Aluminum 80 SCUBA tank only hold 77 cubic feet of air? ©2018-2020 by Mark Derrick, Gas Blending Instructor at Dive Gear Express ...

www.divegearexpress.com

Z Factors for SCUBA | Dive Gear Express®

Cylinder volume is defined by the internal dimensions of the tank, and normally measured in cubic inches or liters of water. Free capacity is ...

www.divegearexpress.com

 

[inquis]

Here are some resources on z-factors. I dont know of a software to do this for scuba mixes sadly.

There are some resources in this thread:

D

Info Thread 'Real gas - the real deal'

Sep 1, 2022

Hello,

I posted this article about real gas models (GERG-2004 among others) for nitrox and trimix blending and associated open source code on thedecostop forum back in 2007. Reposting it here so it doesn't get lost, since both thedecostop and rebreatherworld seem dead.

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Continued in the next post

• daviddem

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[flymolo]

I dont know of a software to do this for scuba mixes sadly.

Calculating SCUBA Cylinder Capacity | Dive Gear Express®

Or why does my Aluminum 80 SCUBA tank only hold 77 cubic feet of air? ©2018-2020 by Mark Derrick, Gas Blending Instructor at Dive Gear Express ...

www.divegearexpress.com

Yeah I was surprised baltic blender and multideco don't provide tools for it. I was aware that compressibility factors exist I am just not sure how much I should be considering them when planning gas margins.

 

[rjack321]

Yeah I was surprised baltic blender and multideco don't provide tools for it. I was aware that compressibility factors exist I am just not sure how much I should be considering them when planning gas margins.

They really dont kick in hard until beyond 3600psi and for the 15/55s and higher mixes. I was just using 300bar tanks with trimix as a worst case example where just pumping them up leads to increasingly diminishing returns.