This International Standard specifies a manual method for the determination of the concentration of methane emissions from stationary sources. This International Standard specifies an independent method of measurement, which is validated for mass concentrations up to 1 500 mg/m3. NOTE 1 An independent method of measurement is used for such purposes as calibration or validation of permanently installed measuring systems. NOTE 2 An “independent method of measurement” is termed “standard reference method (SRM)” in EN 14181[5].