To limit the probability that overtopping of the spill containment area will lead to the spread of liquid outside of the secondary containment, which could lead to the ignition of vapour from a nearby ignition source, which could lead to harm to persons.
To waive the 10% safety factor required in Sentences 4.3.7.3.(1) and (2) for indoor storage tanks for flammable liquids and combustible liquids permitted to be located outside of a storage room.