Calculation of an Acceptable Dig (Gouge) in a S80 SCUBA 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:
    .471″ (min side wall) x .15% = .071″ deep

    b) A dig in the center of the base (the thinnest part of the base) could be:
    .735 (min base) x .15% = .110″ deep

    c) A dig in the radius and footring at the bottom of the cylinder could be:
    .110″ deep + .04″ footring height) = * .150″ deep
    * This dig cannot extend up into the sidewall.

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

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