4.6.2. Fire alarm systems shall be installed:(a) in any new building of mercantile occupancy having more than 2 storeys and where the occupant load exceeds 300 persons, or exceeds 150 persons below or above the first storey;
(b) in any new industrial or commercial establishment of high or medium fire hazard having more than 2 storeys and where the occupant load exceeds 300 persons, or exceeds 20 persons below or above the first storey;
(c) in any new industrial or commercial establishment of low fire hazard where the occupant load exceeds 500 persons or exceeds 75 persons below or above the first storey.