Specifies a set of values of performance characteristics applicable to the continuous measurement, by extractive or non-extractive methods of gas concentrations of sulfur dioxide up to 8 mg/m³.

This International Standard specifies a complete set of values of performance characteristics for automated measuring systems for the continuous measurement of the mass concentrations of sulfur dioxide in stationary source emissions. NOTE 1 If the performance characteristics of an automated measuring system are listed according to Table 1, this ensures that the automated measuring system is reliable and gives satisfactory continuous results. The set of data listed in Table 1 refers to the performance characteristics of measurement methods, including all steps from sampling to recording and, if necessary, storage of data. This International Standard is applicable to extractive and non-extractive automated sulfur dioxide measuring methods. For both methods it implies the applicability of zero and calibration gas and the availability of comparable samples. The automated measuring system can be calibrated with calibration gases, by applying the manual method described in ISO 7934, or by applying an automated measuring system previously verified according to this International Standard using a different principle of detection. The value of the integral performance (3.7) is determined by using ISO 7934 or an automated measuring system verified according to this International Standard with a different principle of detection. At present, the range over which this specification applies is between 0 g/m3 to 0,1 g/m3 and 0 g/m3 to 8 g/m3 (see Table 2 for details). NOTE 2 Although it is impossible to give precise testing details, the requirements and testing principles are also applicable to non-extractive systems. Table 1 – Main performance characteristics Performance characteristics Numerical value Test methods (see Annex A) Detection limit 2 % A.4.2.1.1 Effect of interfering substances ± 2 %a A.4.2.1.2 Response time ≤ 200 sc A.4.2.1.3 Integral performance (sA) ± 2,5 %ad A.4.2.2 a Related to the upper limit of measurement. b The main interfering substances in the flue gas from combustion plants are CO2, CO, NO, H2O and, in smaller concentrations, NO2 and NH3. If the water vapour is not removed from the flue gas of coal and waste fired incinerators, HCl and HN* may also interfere. In special cases there may be other interfering substances (e.g. cyanide). c Assuming an integration time of 30 min. d See 3.7. * See national foreword for details of textual error. The facilities at which the values of the performance characteristics given in Table 1 have been verified according to this International Standard in the appropriate ranges are listed in Table 2. Table 2 – Facilities and measuring rangesb Facility Measuring range g/m3 of SO2a Furnaces for hard coal 0 – 1 to 0 – 8 Furnaces for hard coal with stack gas desulfuration plant 0 to 0,1b Furnaces for brown coal 0 – 0,1 to 0 – 3,0 Furnaces for heavy fuel oil 0 – 0,1 to 0 – 5,0 Refuse incinerator 0 – 0,4 to 0 – 1,0 Coke oven 0 to 1 Calcar with heavy fuel oil 0 to 5 Sulfuric acid recovery plant 0 to 1 a Related to 101,3 kPa, 273 K and dry gas. b See national foreword for additional information.