Fuel factor

The Fuel Factor, f_o, is the ratio of created CO₂ to depleted oxygen in a combustion reaction, used to check the accuracy of an emission measurement system. It can be calculated using the equation

Where %O₂ is the percent O₂ by volume, dry basis, %CO₂ is the percent CO₂ by volume, dry basis, and 20.9 is the percent O₂ by volume in ambient air. The Fuel factor can be corrected for the amount of CO, by adding the percent CO on a dry basis to the CO₂, and subtracting half of the percent CO from the O₂.