35. Mezzanine floor.-

(1) The floor area of mezzanine floor shall not exceed one third area of the main floor or room accommodating the mezzanine floor.

(2) The headroom measured from the surface of the floor to any point on the underside of the mezzanine floor shall not be less than 2.2 mts.

36. Height of room.-

The height of room in a building other than residential occupancy shall be not less than 3.00 metres:Provided that in the case of air conditioned rooms it shall be not less than 2.4 metres.-

37. Water closet.-

Every building shall be provided with at least one water closet.

38. Size of bathroom and latrine.-

(1) The area of bath-room shall not be less than 1.50 sq.m. with either side not less than 1.1m, carpet area of a latrine shall not be less than 1. 1 0 square metres with one side not less than 1.0 metre:

Provided that the area of combined bathroom and latrine shall be not less than 2.2 square metres with one side not less than 1. 1 metres:

(2) The height of bathroom or latrine shall be not less than 2.20 metres.

39. Staircases.-

(1) Any building having more than four floors including basement or sunken floors, shall have at least two staircases, one of which may be an external stairway:

Provided that when the second staircase provided as external stair way conforms to the provisions of fire escape staircase, a separate fire escape stair need not be provided.

Note:- An external stair is one which is connected to public areas and/or common areas on all floors and leads directly to ground, has at least two sides abutting external wall, these two sides being provided as open or with break open glass and has landing areas accessible from the external side or a external stair which is wholly open and removed from the main building, such an external stair shall be removed and away from the main stairway.

(2) The minimum width of stair shall be not less than 1.20 metres [X X X]

(3) The minimum width of tread shall be 30 cms [x x x]

(4) The height of riser shall not exceed 15 cms. [x x x].

(5) The height of handrail shall be not less than 90 cms.

(6) The width of passages giving access to the staircase in any building shall not at any point, be less than the width of the stair.

40. Ramps.-

Ramps if provided as a substitute for stairways shall be laid with a slope not exceeding 1 in 10 and such ramp shall comply with all requirements of a stairway and shall be surfaced with approved non-slippery materials.

41. Corridor, verandahs and passageways.-

The clear width of any corridor, verandah or passageway in any building shall be not less than 1.0 metre at any point.

42. Fire escape staircase.-

(1) Fire escape stair case shall be provided for every buildings of,-

(a) residential occupancies exceeding three storeys above ground level;

(b) occupancies other than residential exceeding two storeys above ground level.

(2) The width of fire escape staircase shall be not less than 75 cm, the width of fire escape stair tread shall be not less than 15 cm, the height of the fire escape stair riser shall not exceed 19 cms, and the number of riser shall not exceed 16 per flight of stairs.

(3) The height of handrail of a fire escape staircase shall not be less than 100 cms.

(4) Fire escape stair shall be constructed only in the exterior of the building and shall be connected directly to the ground.

(5) Fire escape stairs shall have a straight flight.

(6) Entrance to fire escape stair case shall be separated and removed from internal staircase.

43. Travel distance to emergency staircase.-

(1) Every building meant for human occupancy shall be provided with emergency exit sufficient to permit safe escape of occupants in case of fire or whenever other emergency occurs.

(2) Emergency exits shall be located in such a way that the travel distance on each floor shall not exceed 30 metres for every occupant.

44. Fire Protection requirements.-

All requirements in respect of fire protection shall be as in Part IV, Fire Protection in National Building Code of India, 1983 and amendment No. 3 under Fire Protection Annexure 11.

45. Exit Width.-

(1) The unit of exit width used to measure the capacity of any exit shall be 50 cms., a clear width of 25 cms. shall be counted as an additional half unit and clear width less than 25 cms. shall not be counted for exit width.

(2) Occupants per unit exit width shall be as in Table 6.


Occupants per unit exit width
Sl. No. Group of occupancy No. of Occupants per unit exit width of Stairway Doors
(1) (2) (3) (4)
1. Group A1 Residential 25 75
2. Group A2 Special Residential 50 75
3. Group B Educational 25 75
4. Group C Medical/Hospital 25 75
5. Group D Assembly 60 90
6. Group E 50 75
7. Group F Mercantile (Commercial) 50 75
8. Group G1 Industrial 50 75
9. Group G2 Small Industrial 50 75
10. Group  H Storage (including Warehousing) 50 75
11. Group I Hazardous 25 40

(3) For determining the exit required, the number of persons in any floor area or the occupant load shall be based on the actual number of occupants but in case less than that specified in Table 7.


Occupant Load

Sl. No. Group of occupancy Occupant Load (gross area in square meters per person)
(1) (2) (3)
1. Group A1 Residential 12.5
2. Group A2 Special Residential 4.0
3. Group B Educational 4.0
4. Group C Medical/Hospital 15.0
5. Group D Assembly 1.5
6. Group E Office 1.5
7. Group F Mercantile (Commercial) 3 to 6
8. Group G1 Industrial 10.0
9. Group G2 Small Industrial 10.0
10. Group  H Storage (including Warehousing) 30.0
11. Group I Hazardous 10.0

(4) Exits shall be either horizontal or vertical type.

(5) An exit may be a doorway corridor or passageway to an internal staircase or external staircase, ramps to the street or to the roof of a building; it may be a horizontal exit leading to an adjoining building at the same level:

Provided that lifts and escalators shall not be considered as exits.

46. Doorways.-

(1) Every exit doorway shall open into an enclosed stairway or a horizontal exit or a corridor or passageway providing continuous and protected means of egress.

(2) No exit doorway shall be less than 75 cms in the case of residential and 1.2 metres in the case of all other occupancies.

47. Spiral stair fire escape.-

(1) The use of spiral staircase shall be limited to low occupant load and buildings upto 9 metres in height unless they are connected to platforms such as balconies and terraces to allow easy exit.

(2) A spiral staircase shall be not less than 150 cm. in diameter and shall be designed to give adequate head room.

48. Lift.-

(1) Every building exceeding 3 storeys (excluding sunken floors) in the case of hospitals/medical occupancy and 4 storeys (excluding sunken floors) in the case of other occupancies having plinth area more than 2500 sq. metres shall be provided with one lift for every 2500 sq. metres or part thereof exceeding first 2500 sq. metres, in addition to the required number of staircases as per rule 39.

(2) The planning, design and installation of lifts shall be in accordance with Part VIII, Building services, Section 5, Lift, Elevators and Escalators in National Building Code of India, 1983.

(3) Whenever more than one lift is required as per sub rule(1) or byelaws made under the Act, at least one lift shall be a higher capacity  lift that can carry a stretcher

49. Lighting and Ventilation.-

(1) Every habitable room shall be furnished with sufficient number of openings such as windows and ventilators affording effectual means of admission of light and air by direct communication with the external air as provided in the National Building Code, 1983 or shall be sufficiently lighted and ventilated by artificial means.

(2) No portion of a room shall be assumed to be lighted if it is more than 7.5 metres away from the opening assumed for lighting that portion unless it is artificially lighted.

(3) Windows and ventilators which open into a verandah shall be deemed to communicate with the external air, if such verandah is not more than 3  metres wide and open throughout its entire length into an open space open to  the sky the width of such open space being not less than 3.0 metres. Trellising, mesh, grill or net may, however, be provided on the open side of the verandah;

(4) Every kitchen shall be ventilated according to the standards stipulated for habitable rooms and shall have suitable flue for the escape of smoke and heated air unless it is provided with an approved form of smokeless installation.

(5) Every bathroom or latrine shall be provided with sufficient light and ventilation.-

(6) Every bathroom or latrine shall have at least one of its walls abutting on an open space or open verandah or an air shaft if not centrally air conditioned; the size of air shaft shaft not be less than that specified in Table 8.


Size of Air Shaft
Sl. No. No. of  Storeys Area of the airshaft in Square meter Minimum width of Airshaft in meter
(1) (2) (3) (4)
1. Upto 3 1.08 0.9
2. Upto 6 2.4 1.2
3. Upto 10 3.0 1.5
4. Above 10 5.0 2.0

50. Recreation space

(1) Any residential apartment having more than 12 dwelling units in a single plot or single building, shall be provided with a recreation space of suitable size.

(2) The recreation space as per sub rule(1) shall have not less than 7.5 per cent of the total carpet area of all the units taken together and may be provided either inside a building or outside a building or both and if t is provided outside a building it shall be exclusive of parking areas, drive ways and other utility areas.


1) Spaces like swimming pool, recreation hall or health club shall also be considered as recreation space for this purpose.

(2) The recreation space may be provided as a single unit or as different units.

51. Certain Buildings exempted.-

Family residential buildings with not more than three floors constructed in plots with are not exceeding 283.36 sq meters(7cents) shall be exempted from the provisions in this chapter other than that in rule 42 and rule 44