The subscript "in vessel" is for the reactor or building. The subscript "experimental" applies
to data determined in the laboratory using either the vapor or dust explosion apparatus. Equation
6-20 allows the experimental results from the dust and vapor explosion apparatus to be applied
to determining the explosive behavior of materials in buildings and process vessels. This
is discussed in more detail in chapter 9. The constants KG and Ks, are not physical properties
of the material because they are dependent on (1) the composition of the mixture, (2) the mixing
within the vessel, (3) the shape of the reaction vessel, and (4) the energy of the ignition
source. It is therefore necessary to run the experiments as close as possible to the actual conditions
under consideration.