How Much Gas is coming from the Gas Cylinder?

In order to dilute the O2 in a container headspace it has been shown that the gas space or head space needs to be purged with a volume of inert gas that is equal to the volume of the headspace, 4 to 5 times to reduce the Oxygen level to close to zero.  See Factory Mutual Insurance Co., FM Global Property Loss Prevention Data Sheets 7-59, September 1977, revised 2000.

Testing for Oxygen presence is not trivial.  A common response is for the winemaker to say, “Well my match went out, that’s proof of no Oxygen.”   But it is not.

In 1993 some Australian spelunkers studied the problem, and found that:

  • A Butane Flame extinguishes at 14.5% O2
  • Matches sputter out at 13% O2
  • Matches will not ignite below 10% O2

This is a wake-up call for some.  Gaseous O2 can be measured accurately with a probe that costs probably less than $300.

I include the following chart of Gas Cylinders and their Volumes below to make it easier to determine your gas needs.

This chart tells you how much gas is in each tank, and how much gas is released per a 100PSI pressure drop, for the various Tank sizes available:

Cylinder Contents at STP,  Starting with Cylinder at 3,000 PSI    
Cylinder height with Guard, inches Cu. Ft. of Gas in cylinder at start “Gallons” of Gas at Start “Gallons” of gas  released per 100 PSI Pressure Drop
60 330 2469 82.3
56 250 1870 62.3
48 122 913 30.4
36 80 599 20.0
27* 55 411 13.7
22* 40 299 10.0
18* 22 165 5.5
* No Guard
Note: “At STP”  means  “At Standard Temperature and Pressure”,                                                    (20 Degrees C, and 1 atmosphere).