ISO 15971
ISO 15971 is an ISO standard for calorific value measurement of natural gas and its substitutes. The methods it covered does not involve gas composition determination and the related calculations. The standard includes the operation of instruments that are used in the measurements and the guidelines in selecting and assessing, as well as the installation and the operation of such instruments. See also
Wobbe index

External links
ISO 15971:2008 Natural gas. Measurement of properties. Calorific value and Wobbe index

Natural gas
Fuels
15971