How Do We Use The Fo Factor in Determining Validity of Orsat/CEM Analysis for O2/CO2?

Fo factors can be used to evaluate the correctness of the Orsat or CEM system performing analysis for CO2/O2.  The following table illustrated the typical range for Fo factors for specific fuel types:

Using the following formula, one can check the accuracy of the Orsat or CEM used to monitor O2 and CO2:

Fo  =  20.9- O2/ %CO2

If calculated Fo value does not fall within this range of +/- 10 %, then something is wrong with the reported CO2 and O2 concentrations.