Specifications on Compressed Gas Cylinders

Compressed gas cylinders can be hazardous if overfilled. Specifications for a compressed gas cylinder, or tank, are marked on its neck and body. The specifications relate how much the tank contains, how much to fill it and with what to fill the tank.

  1. Size

    • The tank's size is marked on the tank. It is calculated as the tank's diameter multiplied by its height.

    Capacity

    • The capacity of a tank is how much water it can hold internally when filled. For example, a normal scuba cylinder is referred to as a 12L cylinder even though it holds much more in terms of compressed air.

    Material

    • The tank's material is stamped on the tank's neck. For compressed air cylinders, the material is either aluminum or steel.

    Contents

    • A tank's gas contents should be marked on the tank's side. Stickers identify the kind of gas the cylinder contains.

    Working Pressure

    • The term "working pressure" on a tank means the pressure to which the tank can be filled. That amount also is an indication for hydrostatic testing, when the tank is overpressurized to test its structural integrity.