Dead ring test

From GAWDAwiki

A dead ring test, or "hammer test," is a test used to determine the soundness of a cylinder by striking the side of the cylinder. A clear bell-like sound indicates that the cylinder is satisfactory. A dull sound indicates that the cylinder is not suitable for filling with compressed gas.^[1]

References

1. http://www.fda.gov/Cder/guidance/cmgg89.htm