Calculating Gas Volume in a SCUBA cylinder

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Knowing how much gas is in your cylinder is an important part of the dive planning process. You’ll use this along with your SAC rate (surface air consumption rate) in order to find out if you have enough gas in your cylinder to safely get back to the surface, taking into account a third reserve.

Rating: 4.71

  1. djjoshua007 says

    Bar? WTF? im in the USA… Go eat some spotted dick!!!!

  2. Maxim C says

    Good video. Thank you. You just have to remember that 1 bar is not exactly = to 1 atm, to make sure the volume in liters are correct divide your number by 1.01325. In you example 12L x 230bar/1.01325=2723 L not 2760L.

  3. anant nirvana says



    BAR is so confusing when I've always been using psi and cubic feet

    I would take working volume ÷ working pressure = baseline

    baseline × psi in tank = volume in tank

    example ~

    100 cubic foot tank (when filled to working capacity) with a rated pressure of 3,500

    100 ÷ 3,500 =.0285
    .0285 × 2,500psi = 71.25cuft

    this is helpful in knowing how much volume one consume at depth

    an air consumption of 1cuft/min on the surface is 4 cuft/min at 99ft

    71.25cuft ÷ 4cuft/min = 17.81 minutes of air at 99ft


    If you would be at 99ft for 25 minutes, 25min × 4cuft/min = 100cuft consumed at 99ft

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