Measuring Flare Gas Within the European Union Emissions Trading SchemeMeasuring flare gas emissions in the offshore oil and gas industry is notoriously difficult. In fact, the EU commission recognized this and decided not to apply the same accuracy targets for flare gas as other important gas streams such as fuel gas, which, for Tier 3 is ± 2.5 percent. The problem is that not only can the gas be dirty and corrosive, but the variation in flow rates between the minimum and maximum flow can be enormous. Due to the fact that flare gas is effectively wasted gas under normal operation, the operators would hope for a very low flow rate indicating a stable process. During upset conditions, however, the operators can need to vent large quantities of gas to prevent over pressure within the system and this can result in extremely high flow rates through the flare stack.