Chapter 6Provisions for High Rise Development

6.1 General.- Buildings of height 15m and above shall be considered as high-rise building.

Note: These provisions shall be in addition to the Chapter 4 for plan sanction procedure, general building requirements (low/high) given in Chapter 5 of this document and structural safety given in Chapter7

6.2 Means of access

(1) A building shall abut on a street or streets or upon spaces directly connected from the street by a hard surface approach road. The width of approach road shall be as prescribed in the Zonal Regulations.

(2) The approach road to the building and open spaces on its all sides shall be as prescribed in the Zonal regulations and wherever vehicular driveways are required to be provided, the same shall be reinforced to ensure safety of the fire equipment and capable of taking the weight of Fire engine, weighing up to 45 ton

(3) The said driveway shall be kept free of obstructions and shall be motorable.

(4) Main entrances to the premises shall be of adequate width to allow easy access to the fire engine and in no case, it shall measure less than 6.0m. The entrance gate shall fold back against the compound wall of the premises, thus leaving the exterior access way within the plot free for movement of fire service vehicles. If archway is provided over the main entrance the height of the archway shall not be at a height less than 4.5m.

6.3 Parking Spaces

(1) The parking spaces shall be provided as per the provisions of Master Plan and Zonal Regulations as prevalent. The location of parking spaces shall be well ventilated.

(2) In case of high-rise buildings parking will be permitted at any/all of the following:

(a). Basements;

(b). Stilt floor; and

(c). Stacked/ Multi-level/ Automated parking.

6.4.1 Doorways.- The doorway requirements shall be as prescribed in Clause no.5.2.6

6.4.2 Revolving Doors.-Revolving door shall not be provided as a means of fire exit

6.4.3 Stairways

(1) A staircase shall not be arranged round a lift shaft.

(2) The staircase shall be ventilated to the atmosphere at each landing and a vent at the top; the vent openings shall be of 0.5Sq.m in the external wall at the top. If the staircase cannot be ventilated, because of location or other reasons, a positive pressure 50 Pa shall be maintained inside. The mechanism for pressurizing the staircase shall operate automatically with the fire alarm. The roof of the shaft shall be 1m above the surrounding roof. Glazing or glass bricks if used in staircase, shall have fire resistance rating of minimum 2 hours.

(3) The minimum width of staircase shall be as per Table 5.2:

(4) Handrails shall be provided with a minimum height of 1.0m from the centre of the tread.

(5) Access to main staircase shall be gained through adequate fire resistance rating specified in Chapter12 Automatic closing doors shall be placed in the enclosing walls of the staircases. It shall be a swing type door opening in the direction of the escape.

(6). No living space, store or other fire risk shall open directly into the staircase or staircases.

(7). External exit door of staircase enclosure at ground level shall open directly to the open spaces or can be reached without passing through any door other than a door provided to form a draught lobby

(8). The exit sign with arrow indicating the way to the escape route shall be provided at a height of 0.5m from the floor level on the wall and shall be illuminated by electric light connected to corridor circuits. All exit way marking signs should be flushed with the wall and so designed that no mechanical damage shall occur to them due to moving of furniture or other heavy equipment’s. Further all landings of floor shall have floor indication boards indicating the number of floor. The floor indication board shall be placed on the wall immediately facing the flight of stairs and nearest to the landing. It shall be of size not less than 0.5x 0.5m and it shall be prominently on the wall facing the staircase.

(9). In case of single staircase, it shall terminate at the ground floor level and the access to the basement shall be by a separate staircase. However, the second staircase may lead to basement levels provided the same is separated at ground level by either a ventilated lobby with discharge points at two different ends or through enclosures with fire resistance rating door specified in Chapter12 or through a fire protected corridor.

6.4.4 Lifts.- General requirements of lifts shall be as follows:

(1) All the floors shall be accessible for 24 hours by the lifts. The lifts provided in the buildings shall not be considered as a means of escape in case of emergency. In a dual line arrangement (lifts opposite to each other) the lobby may be between 1.5 times to 2.5 times the depth of one car. For in-line (single line) arrangements the lobby may be typically half of the above recommendations.

(2) Grounding switch, at ground floor level, to enable the fire service to ground the lift shall also be provided.

(3) The lift machine room shall be separate and no other machinery shall be installed therein.

(4) Walls of lift enclosures and lift lobby shall have fire rating of 2 hour; as specified in Chapter12 lifts shall have a vent at the top of area not less than 0.2Sq.m

(5) Lift car door shall have a fire resistance rating of 1 hour.

(6) Lift lobby doors in lift enclosures shall have fire resistance as specified in Chapter12.

(7) Collapsible gates shall not be permitted for lifts and shall have solid doors with fire resistance of at least 1 hour.

(8) If the fire man lift shaft and lobby is in the core of the building, a positive pressure between 25 and 30 Pa shall be maintained in the lobby and a positive pressure of 50 Pa shall be maintained in the lift shaft. The mechanism for pressurization shall act automatically with the fire alarm; it shall be possible to operate this mechanically also.

(9) Lifts if communicating with the basement, the lift lobby of the basements shall be pressurized as suggested in clause 12.9.1(g) and 12.9.1(h) with self-closing door with fire resistance rating as specified in Chapter 12. Telephone or other communication facilities shall be provided in lift cars and to be connected to fire control room for the building.

(10) Exit from the fire man lift lobby, if located in the core of the building, shall be through a self-closing fire door of half an hour fire resistance.

(11) Suitable arrangements such as providing slope in the floor of lift lobby shall be made to prevent water used during fire-fighting, etc., at any landing from entering the lift shafts.

(12) A sign shall be posted and maintained on every floor at or near the lift indicating that in case of fire, occupants shall use the stairs unless instructed otherwise. The sign shall also contain a plan for each floor showing the locations of the stairways. Alternate source of power supply shall be provided for all the lifts through a manually operated changeover switch.

(13) For Pressurization Specifications of various building components refer NBC Part-4 Fire and Life Safety Pressurization of Staircases (Protected Escape Routes)

6.4.5 Basements

6.4.5.1 General requirements.- Basement floors shall be permitted as prescribed in the Zonal Regulations

6.4.9 Glass Façade/ Service Ducts/Shafts/ Refuge Area/ Vents

(1) An Opening to the glass façade of min. width 1.5m and height 1.5m shall be provided at every floor at a level of 1.2m from the flooring facing compulsory open space as well as on road side. Construction that complies with the fire rating of the horizontal segregation and has any gap packed with a non-combustible material to withstand thermal expansion and structural movement of the walling without the loss of seal against fire and smoke..

(2) (2) Mechanism of Opening: The openable glass panel shall be either left or right shall have manual opening mechanism from inside as well as outside. Such openable panels shall be marked conspicuously so as to easily identify the openable panel from outside.

(3) Fire seal to be provided at every floor level between the external glazing and building structure.

(4) The glazing used for the façade shall be of toughened (tempered) safety glass as per I.S.2553.

(5) To avoid fire propagation vertically from one floor to another floor, a continuous glass I must be separated internally by a smoke/ fire seal which is of non-combustible material having a fire resistance rating of not less than 2 hours.

(6) Service ducts and shafts shall be enclosed by walls and doors with fire resistance rating (Refer Clause 12.7.1 of Chapter 12). All such ducts/shafts shall be properly sealed and stopped fire ingress at all floor levels.

(7) A vent opening at the top of the service shaft shall be provided having an area between one- fourth and one-half of the area of the shaft.

(8) The openable vent of minimum 2.5% of the floor area shall be provided. The openable vent can be pop out type or bottom hinged provided with fusible link opening mechanism and shall also be integrated with automatic Smoke Detection System.

(a) Alternate vertical glass panels of the façade shall be openable type with the mechanism mentioned above in order to ventilate the smoke.

(b) Refuge areas covered with the glass façade shall have all the panels fully openable (either left or right hinged) both from inside as well as outside. Glass quality and Practice of use of Glass in buildings shall have to be in conformity with the BIS codes as given in Table 6.1 below:

6.5.1 Staircase and Corridor Lighting

(1) The staircase and corridor lighting shall be on separate service and shall be independently connected so as it could be operated by one switch installation on the ground floor, easily accessible to fire-fighting staff at any time irrespective of the position of the individuate control of the light points, if any.

(2) Staircase and corridor lighting shall also be connected to alternate supply from parallel high-tension supply or to the supply from the stand-by generator.

(3) Emergency lights shall be provided in staircase and corridor/ passageway, horizontal exits, refuge area; and all wires and other accessories used for emergency light shall have fire retardant property

6.5.2 Electrical Services

(1) The electric distribution cables/wiring shall be laid in separate duct the duct shall be sealed at every floor with non-combustible materials having the same fire resistance as that of the duct. Low and medium voltage wiring running in shaft and in false ceiling shall run in separate conduits.

(2) Water mains, telephone cables, intercom cables, gas pipes or any other service line shall not be laid in the duct for electric cables. Use of bus ducts/solid rising mains instead of cables is preferred.

(3) The provision of dedicated telecommunication ducts for all new building proposals is mandatory for conveyance of telecommunication and other data cables.

(4) Separate circuits for water pumps lifts, staircases and corridor lighting and blowers for pressurizing system shall be provided directly from the main switchgear panel (for detailed specifications refer NBC 2005, Part-4 Fire and Life Safety).

6.5.3Alternate Source of Electric Supply.- A stand-by electric generator shall be installed to supply power to staircase and corridor lighting circuits, fire lifts, the stand-by fire pumps, pressurization fans and blowers, smoke extraction and damper system in case of failure of normal

electric supply. The generator shall be capable of taking starting current of all the machines and circuits stated above simultaneously. If the stand-by pump is driven by diesel engine, the generator supply need not be connected to the stand-by pump.

6.5.4Air-conditioning.- Air-conditioning shall conform to the following:

(a). Escape routes like staircases, common corridors, lift lobbies, etc. shall not be used as return air passage.

(b). The ducting shall be constructed of substantial gauge metal in accordance with good practice.

(c). Wherever the ducts pass through fire walls or floors, the opening around the ducts shall be sealed with materials having fire resistance rating of the compartment.

(d). Where duct crosses a compartment which is fire rated, the ducts shall be fire rated for same fire rating. Further depending on services passing around the duct work, which may get affected in case of fire temperature rising, the ducts shall be insulated.

(e). ceiling Metallic ducts shall be used even for the return air instead of space above the false.

(f). Where plenum is used for return air passage, ceiling and its fixtures shall be of non-combustible material.

(g). The materials used for insulating the duct system (inside or outside) shall be of non-combustible material; glass wool shall not be wrapped or secured by any material of combustible nature.

(h). Air ducts serving main floor areas, corridors, etc. shall not pass through the staircase enclosure.

(i). The air-handling units shall be separate for each floor and air ducts for every floor shall be separated and in no way inter-connected with the ducting of any other floor.

(j). If the air-handling unit serves more than one floor, the recommendations given above shall be compiled with in addition to the conditions given below:

(i). Proper arrangements by way of automatic fire dampers working on smoke detector / or fusible link for isolating all ducting at every floor from the main riser shall be made.

(ii). When the automatic fire alarm operates, the respective air-handling units of the air conditioning system shall automatically be switched off.

(iii). The vertical shaft for treated fresh air shall be of masonry construction.

(iv). The air filters of the air-handling units shall be of non-combustible materials or fire rated (Refer Clause 12.7.1 of Chapter 12)

(v). The air-handling unit room shall not be used for storage of any combustible materials.

(vi). Inspection panels shall be provided in the main trunk line to facilitate the cleaning of ducts of accumulated dust and to obtain access for maintenance of fire dampers.

(vii). No combustible material shall be fixed nearer than 150 mm to any duct unless such duct is properly enclosed and protected with non-combustible material (glass wool or spyglass with neoprene facing enclosed and wrapped with aluminium sheeting) at least 3.2 mm thick and which would not readily conduct heat.

6.5.5 Transformers

(1) If transformers are housed in the building below the ground level it shall be necessarily in the first basement in separate fire resistance room of 4 hours rating. Transformer shall be dry type and shall be kept in an enclosure with walls, doors and cut-outs having fire resistance rating of 4 hour. The room shall necessarily be at the periphery of the basement having separate and direct access from open area at ground floor through a fire escape staircase. The entrance to the room shall be provided with a steel door of 2 hours fire rating. A curb of a suitable height shall be provided at the entrance in order to prevent the flow of oil from ruptured, transformer into other parts of the basement. The switchgears shall be housed in a separate room separated from the transformer bays by a fire-resisting wall with fire resistance not less than 4 hours.

(2) The transformer shall be protected by an automatic foam sprinkler system. When housed at ground floor level it/they shall be cut-off from the other portion of premises by Fire Resisting Walls of 4 hours rating.

(3) A tank of RCC construction of adequate capacity shall be provided at lower basement level, to collect the oil from the catch pit in case of emergency. The pipe connecting the catch-pit to the tank shall be of non-combustible construction and shall be provided with a flame-arrester.

(4) The electric sub-station shall be located in a separate building in accordance to I.E. Rules 68(I) and 64(I) (a).

(5) If this is not possible due to site conditions, the sub-station shall be located on the ground floor. As far as possible sub-station shall not be installed in a basement, for such situations special provisions like mechanical ventilation, wherever required, cable ducting, cable trays, top/bottom entry of HV/LV cable, hooks on Transformer(s) and HV panels, adequate fire detection

and fire-fighting arrangement, adequate drainage, effective measures to prevent flooding etc. shall be provided. Adequate precautions shall also be taken for water proofing to prevent seepage of water. A ramp shall also be provided with a slope, not steeper than 1 in 7, for easy movement of equipment’s to and from sub-station.

(6) Fire regulations – The installations shall be carried out in conformity with the local regulations and rules there under wherever they are in force. At other places NBC guidelines shall be followed.