Question: how is scba working duration calculated?
Answer: The duration of the cylinder can be calculated with this formula: volume (in liters) * pressure (in bars) / 40 - 10 in minutes (the 10 is subtracted to provide a safety margin), so a 6-liter cylinder, of 300bar, is 6 X 300 / 40 - 10 = 35 minutes working duration.