To supersede the requirement for a minimum 1.5 h rated fire separation as stated in Sentence 9.10.9.16.(1) by permitting a lower minimum rated fire separation between storage garages, on the basis that the number of vehicles permitted in the garages is limited, thus minimizing the fire load and fire risk.
This is to limit the probability that fire will spread from a storage garage to other parts of the building, which could lead to harm to persons in the other parts of the building.