N.1. The specific volume of acetylene gas at one atmosphere and at the temperature of 70°F shall be 14.7 cubic feet per pound.

N.2. Verification of net quantity statements for cylinders of argon, helium, hydrogen, nitrogen and oxygen shall be in accordance with the Tables of Industrial Gas Container Contents and Density for Oxygen, Argon, Nitrogen, Helium and Hydrogen listed on National Bureau of Standards Technical Note issued in June 1985 and incorporated herein by reference.

N.3. Allowable Difference. If the stamped or stenciled tare is used to determine the net contents of the cylinder, the allowable difference between the actual tare weight and the stamped (or stenciled) tare weight, or the tare weight on a tag attached to the cylinder, for a new or used cylinder shall be:

Average Requirements. When used to determine the net contents of cylinders, the stamped or stenciled tare weights of cylinders at a single place of business found to be in error predominately in a direction favorable to the seller and near the allowable difference limit shall be considered to not be in conformance with these requirements.