This document defines a gas chromatographic analysis for the determination of the composition of fuel gases, as used in refinery heating gas. These results are used to calculate the carbon content and the lower calorific value. With this gas chromatographic analysis, an overall of 23 refinery heating gas components are determined in concentrations as typically found in refineries (see Table 1 for further details). Water is not analysed. The results represent dry gases. NOTE 1 – Depending on the equipment used, there is a possibility to determine higher hydrocarbons as well. NOTE 2 – For the purposes of this document, the terms "% (V/V)" is used to represent the volume fraction (φ). IMPORTANT – This document does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this document to establish appropriate safety and health practices and determine the applicability of regulatory limitations.