12.9.1 The basement shall not be used for residential purposes.
12.9.2 The construction of the basement shall be allowed by the Authority in accordance with the land use and other provisions specified under the Development Control Rules.
12.9.2.1 The following uses shall be permitted in the basements:
a) Storage of household or other goods of ordinarily non-combustible material;
b) Strong rooms, bank cellars, etc;
c) Air conditioning equipment and other machines used for services and utilities of the building; and
d) Parking spaces.
The Authority may also consider permitting mercantile occupancy as well as institutional occupancy for medical, health care services involving radiation facilities in the first basement subject to compliance of all requirements for fire safety in accordance with Part 4 'Fire and Life Safety' of the Code and necessary measures for required lighting, ventilation and water supply, drainage and sanitation.
12.9.2.2 The basements can be permitted below the ground and beyond the building lines at ground level subject to a clear minimum front margin of 4.5 m and side and rear margins of 3 m, and further subject to non-habitable uses and provision for mechanical ventilation and all safety provisions and drainage (see Fig. 11). However, it is essential that the basement top slab below the external circulation at ground level should be designed for fire fighting vehicular loads as given in 4.6.
12.9.3 The basement shall have the following requirements:
a) Every basement shall be in every part at least 2.4 m in height from the floor to the underside of the roof slab or ceiling;
b) Adequate ventilation shall be provided for the basement. The ventilation requirements shall be the same as required by the particular occupancy according to byelaws. Any deficiency may be met by providing adequate mechanical ventilation in the form of blowers, exhaust fans, air conditioning systems, etc;
c) The height of the ceiling of any basement shall be minimum 0.9 m and the maximum, 1.2 m above the average surrounding ground level. However, in case of parking, mercantile or business occupancy at ground floor, minimum height of the ceiling of the basement may
PART 3 DEVELOPMENT CONTROL RULES AND GENERAL BUILDING REQUIREMENTS
be 0.3m above the average surrounding ground level subject to mechanical ventilation being provided (see Fig. 11);
d) Adequate arrangements shall be made such that surface drainage does not enter the basement;
e) The walls and floors of the basement shall be watertight and be so designed that the effects of the surrounding soil and moisture, if any, are taken into account in design and adequate damp proofing treatment is given;
f) The access to the basement shall be separate from the main and alternative staircase providing access and exit from higher floors. Where the staircase is continuous in the case of buildings served by more than one staircase, the same shall be of enclosed type serving as a fire separation from the basement floor and higher floors. Open ramps shall be permitted if they are constructed within the building line subject to the provision of (d);
g) Access to basements through ramps shall be permitted subject to provision of (d). The requirements for the ramps shall be in accordance with 4.6.1.3 [see also Fig. 8 (b)];
h) For all public buildings and uses including group housing, having basement going up to more than one level, access to all levels shall also be provided through lift.
The exit requirements in basements shall comply with the provisions of Part 4 ‘Fire and Life Safety’ of the Code.