Calculation of an Acceptable Dig (Gouge) in a 20 lb. CO2 Cylinder

In CGA pamphlet C-6.1, Standards for Visual Inspection of High Pressure Aluminum Compressed Gas Cylinders, it states in section 4.2 that cuts or digs are acceptable to the following limits:

  1. Unknown wall thickness, maximum dig = .031″ deep
  2. Known wall thickness, maximum dig = 15% of minimum design wall thickness.

    a) A dig in the sidewall could be:

          .320″ (min side wall) x .15% = .048″ deep

    b) A dig in the center of the base (the thinnest part of the base) could be:

          .515 (min base) x .15% = .077″ deep

    c) A dig in the radius and footring at the bottom of the cylinder could be:

                             = * .128″ (1/8″) deep

          * This dig cannot extend up into the sidewall.

  3. The length of the dig must be less than 6.0″.