Section 18 in Bangalore Mahanagara Palike Building Bye-laws 2003
18. Basement floor
18.1(a)Basement floors shall not be used for purposes other than parking and for locating machines used for service and utilities of buildings.(b)Strong rooms only in case of bank buildings. The area to be used for this purpose shall be reckoned for FAR purposes.(c)Installation of Radiology and X ray equipment only in case of Hospital buildings having a capacity of more than 50 beds without office. The area to be used for this purpose shall be reckoned for FAR purposes.18.2One basement in the intensely populated are (A Zone) be permitted only for parking purpose, if the area of the premises is 500 sq. mtrs and above with a minimum road width of 12m.18.3When a basement floor is proposed for car parking. Convenient entry and exit shall be provided to the basement. Adequate drainage, ventilation and lighting arrangements shall be made to the satisfaction of the Authority.18.4If the plinth of the ground floor of the building is constructed leaving more set back than the minimum prescribed, the basement floor may extend beyond this plinth; but no part of the basement shall extend beyond the minimum set backs prescribed to the building within the plot.18.5Basement floor is not permissible on sites where the setbacks prescribed in Table 4 are less than 2 metres. In such cases, basement floor may be permitted if setbacks are increased to at least 2 metres.18.6Access to the basement shall floor used other than for parking purposes be from inside the building.18.7(i)Every basement storey shall be atleast 2.4 mtr. in height from the floor to the bottom of the roof slab/ beam / ceiling (whichever is less) and this height of B.F shall not exceed 2.75 metres. In case of high rise buildings/Three Star/ Five Star Hotel Complexes, where extra height is necessary for the installation and running of machinery, or for the purpose of double storeyed car parking where mechanical lifts are used for parking at least for one level, the basement floor may be lowered so as to increase the height upto 3.6 mtrs. This increase in height shall be limited to the area actually required for the machinery or for car parking. Clearance from the Fire Force Department shall be furnished by the applicant for permitting such increase in height.(ii)Adequate ventilation shall be provided for the basement storey. The standard of ventilation shall be the same as required by the particular occupancy according to these bye-laws. Any deficiency may be met by providing adequate mechanical ventilation in the form of blowers, exhaust fans, air-conditioning plants, etc.,(iii)The basement storey should not project more than 1.00 mt. above the average Ground level.(iv)Adequate arrangements shall be made to ensure that surface drainage does not enter into a basement storey18.8The basement floor shall not normally be partitioned. If the ventilation standards as laid down in sub-clause (ii) of bye-law 18.7 are met with, the partition of basement may be permitted.18.9Adequate protection against fire shall be provided to the basement storey. The roof separating the basement and the floor above shall be constructed of materials like RCC or such other material which can provide resistance against fire for atleast two hours.Where a basement floor is permitted in apartment houses (residential flat) and hotels, the owner shall display the basement plan at the entrance. Thimbles (metal rings to receive wires/ropes) shall be provided in the roof of the basement and their positions clearly indicated on the plan. One fire extinguisher for every 100 sqm. of basement area or part thereof, shall be provided.18.10The walls and the floors of the basement shall be watertight and shall be so designed that the hydraulic pressure of the sub-soil water level is fully arrested.18.11Necessary arrangements shall be made to prevent moisture on walls.18.12No place in a basement floor shall be more than 11.25 Mtrs away from the exit in case of residential / educational / institutional / hazardous buildings, 15 mtrs for commercial buildings and 22.5 mtrs for industrial buildings.18.13One additional basement for all buildings exceeding five floors may be permitted for parking and machines used for services and utilities of the buildings. The maximum number of basements in such buildings shall be two.18.14Two additional basements in case of three star and above hotels may be permitted for parking and machines used for service and utilities of buildings. The maximum number of basements in such buildings shall be three.
