To limit the probability of the overtopping of the spill containment area, which could lead to the spread of flammable liquids and combustible liquids outside that area, which could lead to the accumulation of vapour in ignitable concentrations, which could lead to the ignition of vapour from a nearby ignition source, which could lead to damage to the building.
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 in a storage room required in Sentence 4.3.13.4.(1).