On and after July first, nineteen hundred fifty-seven, in every room used for class B occupancy whether in a class A or class B non-fireproof converted dwelling, there shall be one or more sprinkler heads. Such sprinkler heads shall be installed in accordance with the supplementary rules and regulations of the department. This requirement shall not apply to dwellings which have a required second means of egress.
The requirements of this section shall not apply to a dwelling located within an area designated on the master plan as an area suitable for development and redevelopment, provided (a) that the agency in charge of such clearance shall have certified to the department on or before February first, nineteen hundred fifty-nine that the dwelling will be demolished within one year after the service of notice of violation and (b) that the dwelling is not in violation of any rules and regulations relating to overoccupancy, egress or fire protection. Such temporary exemption from the requirements of this section may be extended for an additional period of not more than six months upon renewal of such certification of demolition and safety.