How long will each fill of the oxygen cylinder last?
By recalculating the exhaled gases, removing the CO2 waste product and replenishing the oxygen the Inspiration limits the gas removal from the oxygen cylinder to the same volume that we consume for metabolism. That is, between 0.5 and 3.5 liters per minute depending on the person and the work rate. Mr. Average consumes approximately 1 litre of oxygen per minute and in general, women consume less. Filled to 200 bar the Inspiration’s 3 litre oxygen cylinder contains 600 liters of oxygen. Therefore, at the average consumption rate of 1 lpm, theoretically, each fill should last 600 minutes or 10 hours. In practice some gas is lost during mask clearing and extra O2 is added during ascents. Nevertheless, it is realistic to achieve at least 6 hours diving from one 3 litre cylinder of oxygen.
