Section 46(2) in Tamil Nadu Combined Development and Building Rules, 2019
(2)Directorate of Fire and Rescue Services Standards:(i)No transformer shall be located below the first basement or above the ground floor(ii)A sub-station or switch station with apparatus having more than 2000 liters oil shall not be allowed in the case of indoor transformer.(iii)The indoor transformer should preferably be housed in a fireproof room with walls and doors sufficient fire rating.(iv)The room in the ground floor of the basement housing the transformer shall have a free access to the outside.(v)There shall be a curb or a dwarf wall around the transformer so that oil spills if any, is contained within the curb. There shall also be a suitable drain with a '(vi)If in the basement, the transformers shall be adequately protected against fire by a high velocity water spray or a CO2 flooder of suitable capacity, depending upon the size of the transformer.(vii)The switch-gears, if any shall be housed in a separate room with suitable fire resistance walls.(viii)The transformers shall be located only in the periphery of the basement or ground floor, observing suitable clearances.(ix)DCP or CO2 portable fire extinguishers of a minimum capacity of 10 kg. shall be kept near the doorway housing the transformer.(x)All indoor transformers shall be subjected to periodic inspection and shall be replaced in good time so that there is no fire risk.(xi)The room shall be well ventilated so that the transformer remains cool.(xii)The room shall have emergency and automatic lighting with independent power supply.
