BiH standard BAS EN ISO 6974-4: 2020, Natural gas - Determination of composition and associated uncertainty by gas chromatography - Part 4: Determination of nitrogen, carbon dioxide and C1 to C5 and C6 + hydrocarbons for laboratory and on-line measuring systems using two columns, second edition, is adopted by translation method.

This International Standard was prepared by ISO Technical Committee ISO/TC 193, Natural Gas, and adopted by CMC as the European Standard.

This part of ISO 6974 specifies a precise method for the determination of the composition of natural gas. The compositional data obtained are used for the calculation of the calorific value, the relative density and Wobbe index. This method requires the use of two columns placed in series in a single-oven gas chromatograph. The combination of two columns makes backflushing possible. All the constituents, including the backflush peak, are detected by a thermal conductivity detector (TCD). This method is derived from ISO 6568, Natural Gas - Simple analysis by gas chromatography. This part of ISO 6974 provides one of the methods that may be used for determining the composition of natural gas in accordance with parts 1 and 2 of ISO 6974.

BiH standard BAS EN ISO 6974-4: 2020 was prepared by the Technical Committee BAS/TC 31, Gas and gas engineering, of the Institute for Standardization of BiH.