Serves as a supplement to published measurement procedures, and provides for the conversion of units of gas volume, or its mass, to energy equivalents through the use of data associated with volume metering practices. Equations, tables, and other data are presented to enhance the utility of orifice meters; rotary, diaphragm and related volume displacement meters; as well as meters designed to measure gas weight throughout, or mass meters. The user is provided examples of measurement calculation procedures and a 17 page appendix which contains such items as the physical constants for gas compounds, mass-volume correlations, equation derivations, a table of the elements associated with natural gases, Btu computations and many others.