How Long Can a SCUBA Diver's Oxygen Tank Work?

Experiments with diving equipment began in the 17th century and the first practical diving suit came along in the 19th century. Self Contained Underwater Breathing Apparatus, or SCUBA, was invented in the 1940s and has remained the predominate form of diving gear.

  1. History

    • Developed in the 1930s and '40s, SCUBA gear replaced the clumsy and dangerous helmet diving suits in use since the 19th century.

    Types

    • Modern scuba sets come in two varieties. Open circuit systems, also called aqualungs, were invented by Jacques Cousteau and Emile Gagnan. They are fairly simple, relatively inexpensive and reliable. Open circuit divers breathe in from the equipment and then exhale waste gas into the surrounding water.

      Older than aqualungs, closed circuit or semi-closed circuit systems aren't as commonly used. Divers using these types of equipment inhale from the tanks and then exhale back into them. The waste gas is cleaned for re-use.

    Function

    • The duration of a dive depends on factors such as the type of equipment, duration of the dive and breathing rate of the diver. An experienced open-circuit diver breathes slowly, making the air in a standard diving cylinder last about 60 to 70 minutes. Inexperienced divers breathe faster and use up their air supply in about 30 minutes.

      Semi-closed and closed-circuit systems are more efficient and last between two and seven hours.