9 Interference effects with CO, CO2, NOx and O2 analysers
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - International Codes - NOx Technical Code (2008) - Technical Code on Control of Emission of Nitrogen Oxides from Marine Diesel Engines - Appendix 4 - Calibration of the analytical and measurement instruments - 9 Interference effects with CO, CO2, NOx and O2 analysers

9 Interference effects with CO, CO2, NOx and O2 analysers

 Gases other than the one being analysed can interfere with the reading in several ways. Positive interference occurs in NDIR and PMD instruments where the interfering gas gives the same effect as the gas being measured, but to a lesser degree. Negative interference occurs in NDIR instruments by the interfering gas broadening the absorption band of the measured gas, and in CLD instruments by the interfering gas quenching the radiation. The interference checks in 9.1 and 9.2 shall be performed prior to an analyser’s initial use and after major service intervals, but at least once per year.

Parent topic: Appendix 4 - Calibration of the analytical and measurement instruments
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