The IFC and IBC are written based on the Maximum Allowable Quantity (MAQ) of the hazardous materials involved. Many will look at the tables and find their MAQ; however, the footnotes contain a lot of liberties that could quadruple the MAQs if certain designs are in place.
Given this basic understanding of maximum allowable quantities and control areas, the various options in the code for increasing the quantities of hazardous materials within a building are as follows: