LAUSR

Flow measurements in industrial ducts and stacks are combined with pollutant or greenhouse gas concentrations to deduce mass emissions. These are then used to populate pollutant emission inventories and are traded under emissions trading schemes. Reference methods for flow are described in ISO 10780 and more recently in EN ISO 16911-1. This paper discusses the key differences between the two standards. We consider sources of error in flow measurement and discuss how each standard addresses them. We find that EN ISO 16911-1 introduces a series of improvements that when combined provide critical uncertainty gains that support compliance with the EU’s Emissions Trading System (EU ETS). All these areas are either not addressed or only partially dealt with in ISO 10780. More specifically, EN ISO 16911-1, (a) specifies a wider range of reference techniques enabling the optimal one to be used for different flue gas environments. (b) Provides a method to correct for cyclonic flow effects. (c) Addresses measurement assembly misalignment and specifies tolerance values for it and (d) provides wall effect correction factors. Most importantly, it has been validated through laboratory and field work. However, the quality control specified in EN ISO 16911-1 is more suitable for measurements to support EU ETS requirements and at times can be too onerous for pollutant mass emission reporting that will usually have less stringent uncertainty requirements.