Government rules and regulations governing high rise buildings Safety and Fire Protection as per NBC

[Srinivasan]

Government rules and regulations governing high rise buildings Safety and Fire Protection as per NBC

Below are the points to be checked for fire protection and safety;

• Suitable provisions should be made in all multi-storied,high-rise buildings depending on the occupants & height of the building&could be in accordance to the provisions of part iv fire protections of the NBC of India.
• In additions to this provisions,he property manager or security in-charge shall make arrangements for extra equipment required,if felt necessary,and shall review it periodically to ensure the property always comply with mandatory requirements.
• Any additions and omissions as per amendments prescribed from time to time of the national building code of India are to be adhered to.
• Building materials
• All load –bearing elements of construction for which the required fire resistance is one hour or more should be of non-combustible material.
• Interior finish material must have rating for flame spread & smoke developed not exceeding very low flame spread limit & should be in accordance with is:1642(classifications)provisions.
• Ceiling lining shall be of non-combustible of plasterboard.
• Stairway and corridor should not contain any combustible material.
• Structural supports&load bearing wall should be 3 hrs fire resistant,transoms&ceiling not less than 2 hrs.
• Walls and partitions separating corridors from floor used for any purpose other than the circulation should be fire resistant not less than 1 hr. these should not have openings other than doors of delivery hatches,which should not be less than 1/2 hr fire resistant.
• Firewalls dividing the building to prevent fire spread should be at least 2 hrs fire resistant.
• Facades excluding doors&windows should be non –combustible materials &the fire distance between the top of the opening on the lower floor&the still of that on the floor above it should be at least 0.9 meters so that the fire would have to travel the distance between the floors.

STAIRCASE ENCLOSURE

• Internal enclosing walls of the staircase shall be of brick or RCC with a fire resistance of 2 hrs &shall be reachable via ventilated lobby through self-closing door rated not less than 2 hours &shall not have glazed or glass bricks.
• The door should be single swing type opening in the direction of escape&should be fitted with check section door closure(panic bars).
• The staircase shall be ventilated on the external wall of the building at each landing or mid landing which should not be a part of corridor..
• Permanent vent at the top equal to 5% of cross sectional area of the enclosure & openable sashes at landings with area not less than 0.5 sqm on external wall shall be provided.the top of the shaft shall be 1 m above the surrounding level.
• The internal walls of the staircase should not have glazed or glass bricks.
• If the staircase cannot be ventilated,electrically operated blowers should maintain a positive pressure of 5 mm water gauge.
• Pressuring mechanism should operate automatically when fire alarm operates,this also can be operated manually,if required.
• Lift enclosures
• Walls enclosing lift shafts should be 2 hours fire rated.
• Shafts should have permanent vent at the top not less than 1800 mm (0.2 sq.m) in clear areas.
• Lift machine room should be preferable above the shaft & separated from the enclosing walls of the shaft.
• Landing doors should open into a ventilated or pressurized corridor/lobby&should be 1 hr fire rated.
• The no of lifts in one lift bank should not be more than 4.
• The shaft of the fire lift shall be separated from the bank by brick or RCC walls whose fire rating should be 2 hrs.
• In the shaft & the lobby are in the core of the building a positive pressure not less than 2.5.mm &not more than 3 mm on water gauge for lobby and not than 5 mm in the shaft should be maintained by electrically operated powers which should operate automatically whenever fire alarm operates.the mechanism should also have facility to operate manually.
• Exit from the lobby,if located in the core of the building,shall be through a self-closing smoke stop door of 1 hr rating.
• Machinery other than that of the lift shall be installed in
• Lift should not normally communicate with the basement,how ever one of them may be permitted provided the lobby is pressurized & separated from the rest of the basement by a smoke actuated fire resistant door of 2 hrs rating.this door should hold open by an electro-magnetic devise or linked with smoke detector
• Fire lifts
• To enable fire services personnel reach top floor with minimum delay,one or more lifts should be available exclusively in an emergency for such personnel.
• The lifts should have a floor area not less than 1.4 sq.m with a minimum dimension of 1.2 m &loading capacity should not be less than 545 kg (8 person)with automatic closing doors.
• Alternate power source of adequate capacity,whose cable run within the shaft should be provided, which should trip automatically over an electrical failure.
• The fire lift should operate by a simple toggle or two button situated at entrance labeling a glass cover box placed adjacent to the lift.when the switch operated,all call points will become inoperative & the lift will be on car or priority control device&will return back to normal once the switch is off.
• The words “fire lift “ should be conspicuously displayed in fluorescent paint on each floor.
• The lift should have doors rated at least for 1 hour.
• The speed of the fire lift should be such that it reaches the top floor from the ground level within 1 minute
• Basements
• All basements shall be separately ventilated.
• Vents with cross sectional area not less than 2.5% of the floor should be spread evenly around the perimeter of the basements.
• A system of inlets and outlets at the basement floor level and smoke outlets at the basement ceiling level must be provided.
• Inlets and outlets should terminate at ground level with breakable stall boards or pavement lights should be in a position in a easily accessible to “fire brigade” personnel for rescue purpose and should be clearly marks “smoke outlet” or “air inlet” near the opening.
• Staircase of basement should be enclosed type having fire resistance of not less than 2 hours
• Staircase should be situated at the periphery of the basement & open on the ground level in open air.
• Communication with the basement should be through a lobby provided with the fire resistance and self closing doors of at least for 1hour rating.
• The staircase should be so provided that all occupants without having traveled more than 18.50 meters could access it.
• A single intake duct may serve all basements , but each base and compartments thereof shall have separate smoke outlet ducts.
• Mechanical smoke extractor for the smoke venting system should be provided from the lower level and should actuate with the heat sensitive detectors or sprinklers installed.
• Floor space division – service ducts
• Floor space division
• If the area of the floor exceeds 750-sq.m. It should be separated into compartments not exceeding the above specified area by means of wall having fire resistance of not less than 2 hours.
• The firewalls should be so erected that it does not exceed a distance of 40 meters.
• If floors have sprinkler system,the above-mentioned area can be increased by 50%.
• Service ducts
• A wall having a resistance not less than 2 hours should enclose service ducts.
• Inspection doors should also fire resistance of 2 hours.
• The ducts should be sealed with light non-combustible material if the cross sectional area of the duct exceeds 1 sq.m.
• A permanent vent must be provided at the top of the service shaft of cross-sectional area not less than 460 sq.m. Or 6.25 cm. For each 900-sq.cm. Area of shaft, whichever is more.
• Refuse chutes & refuse chambers
• Hoppers under refuse chutes must be situated in a well ventilated positions and chutes shall be continues upwards with an outlet above roof level enclosed in a non-combustible wall rated not less than 2 hours.
• The hoppers shall not be located within the staircase enclosure.
• Openings of inspection channels and charging stations shall be fitted with light fitting covers having resistance not less than one hour.
• Flap doors / covers i.e. Push-in or lift-up types is not permitted.
• Refuse chutes shall not be provided in staircase walls, air conditioning shafts etc
• Walls,roofs, floors of refuse chambers should be of impervious non-combustible material with a resistance of at least two hours and must be located at a safe distance from exit routes.
• Staircase & corridor lighting
• These lighting should be on a separate circuit independently connected & be operated by one switch installed on the ground floor preferably in the security cabin & easily accessible to the fire fighting team at all times.
• These lighting shall also have an alternate power source connected to it and should be as per is specification.
• Double throw switches shall be installed to ensure lighting in staircase & corridors do not get connected to two source of supply simultaneously.
• Service room should also have a double throw switch to terminate stand by supply to this circuit.

ELECTRICAL

• Distribution wires and cables should be placed in separate duct, which should be sealed at alternate floors with non-combustible material having fire resistance equivalent to that of the duct.
• Water mains, telephone lines, intercom lines , gas pipeline or any other service line should not be laid in this duct.
• Separate circuits for water pumps, lifts, staircase & corridor lighting & blowers for pressuring system shall be provided directly from the main switch gear panel.
• These circuits must be laid in separate conduit pipes so that fire in one does not affect the others.
• Master switches controlling essential services shall be clearly marked for easy identification.
• Emergency light must be provided in staircase/corridors in all high rise and multi-storied buildings.
• Inspection panel door or any other opening in the shaft must be provided with airtight fire doors having resistance not less than 2 hours.
• Medium and low voltage wires in the shaft running within false ceiling shall be in metal conduits
• Independent & well ventilated service room shall be provided on the ground level from outside or corridor for termination of electric power supply from the licensees’ service & alternate supply cables, the doors provided for such rooms should be fire resistance for at least 2 hours.
• If it is agreed to provide meters on upper floor by the licensee, the such cables should be segregated from the consumers’ cables by a partition in the duct.
• Meters on upper floor shall not open int the staircase enclosures and shall be ventilated directly to open air outside.
• PVC cables should have an additional sheating by compounds sprayed on them after installation
• Alternate source of power supply LPG gas supply pipes
• Power supply
• Standby d.g. Set shall be installed to supply power to the staircase/ corridor lighting circuits, fire lifts, standby fire pump, blower/ pressurization fans, dampers and smoke extractors in case normal power supply fails.
• The generator shall be capable of taking start current of all the machines & circuit simultaneously.
• If standby pump is diesel driven, the generator power supply need not be connected.
• LPG supply pipes
• Theses pipes shall run in shaft exclusive for this purpose & shall be on external walls away from the staircases.
• There shall be no inter-connection between the shaft & rest of the floors.
• Gas meters should be housed in specially fabricated metal cupboards, well ventilated and located on the ground level.
• Air-conditioning
• Ducts should be constructed of sustained gauge metal in accordance with is:655 specifications metal air ducts.
• Opening around ducts passing through firewalls or floors should be properly sealed with fire resisting material such as asbestos ropes or vernacular concrete glass wool.
• As far as possible ,metallic ducts shall be used even for return air.
• Material used for insulating the duct system both from inside and outside shall be of non-combustible material such as glass wool ,spun glass with neoprene facing.
• Area of more than 750 sq.cm. On an individual floor shall be separated by fire wall and automatic dampers for isolation shall be provided where the duct pass through wall.
• Air ducts serving floor areas , corridor ,etc shall not pass through the staircase enclosure.
• AHU units shall as far as possible be separated for each floor, air ducts for each floor should be separated and in no way interconnected with ducting of any other floor.
• Automatic fire dampers shall be provided at the inlet of fresh air duct and return air duct of each compartment on every floor.they shall be so arranged as to close by gravity in the direction of air movement and to remain tightly closed upon operation of smoke detector.
• If “AHU” serves more than one floor, the requirements given above shall be compiled with an addition to the below conditions:
• An arrangement by way of fire dampers working on smoke detector for isolating all ducting on every floor from the main riser is necessary.
• When fire alarm operates, the respective AHU of air conditioning system should automatically be switched off.
• Air filters of AHU shall be of non-combustible material.
• Inspection panel shall be provided in the trunking to facilitate cleaning of duct of accumulated dust & serve as access for maintenance of fire dampers.
• No combustible material should be fixed at a distance less than 15 cms. From any duct unless protected with glass wool, spun glass with neprone facing & enclosed in aluminium sheet of 3.2 mm. Thickness.
• Material used for false ceiling, runners & suspenders shall be of non-combustible material
• Transformers
• Transformers housed in basement should be in the first basement in a separate fire resistant room of 4 hours located at the periphery of the basement.
• The room should have either fixed automatic gas suppression or high pressure emulsifying system as per requirement to protect the transformers housed in basements & shall have metal door of 2 hrs rating at entrance having direct access from outside the building.
• Switch gears must be housed in a separate room away from the transformer bay having fire resistance of at-least 4 hours.
• Transformers at ground level shall be cut of from the rest of portion by a wall of 4 hours fire resistance.
• Transformers are not to be housed on upper floors.
• RCC construction capable of accommodating entire oil of transformer must be at lower level for collecting oil from catch pit in emergency.
• Provision of fire fighting equipment
• Fire fighting equipment shall be distributed all over the building in proportion to the area & occupancy on every floor, basement, lift room, etc. In accordance with is:2217 & is:2190 specifications. Portable extinguishers must be so located, that the base of these should be 75 cms. Above the floor level.
• Premises shall be protected by wet riser/ wet riser-cum- down comer, automatic sprinkler/high pressure water spray or foam generating system. Water tanks & fire pumps required for this purpose shall conform to the requirements of NBC.
• A minimum of two hydrants must be provided with a courtyard.
• Pipe connecting catch pit to the tank should be of non-combustible material & must have flame arrester.
• Wet riser-cum-down comer in the building should be arranged by means of vertical rising mains of not less than 10 meter. Internal diameter with hydrant & hose reel on each floor landing connected to an overhead water storage tank for fire fighting purpose. This should be through a booster pump; whose check & non-return valve must be near to the tank. Gate and non-return valve must be fixed over the underground static tank.
• Fire service inlet at ground level with a non-return valve shall be provided for charging the rising main by service pump not exceeding 2000 r.p.m in case the static pump fails.
• Water int the fire tanks shall exclusively be used for fighting & is not to be utilized for domestic or any other use
• The size of the riser in buildings over 24 meters shall be of 15 cm. Internal diameter with twin hydrant outlets and hose reel on each floor.
• A facility to boost water pressure in the riser directly from the mobile pump must be provided to the wet riser system with check/gate/non-return valve.
• Rubber hose reel with internal diameter not less than 19 mm. Along with shut-off branch with nozzle of 4.8 mm must also be provided.
• Is:3644 specifications, code of practice for installations, of internal fire hydrants in multi storied high rise buildings should be adhered to.
• First aid hose(rubber) reels should confirm is:884 specifications & should be connected to one of the female couplings of the landing valve directly to the riser.
• Static water storage tank
• Sufficient water should always be available for fire fighting purpose in the underground tank & covering slab should be able to withstand 25 tonnes weight.
• Replenishment of water from main/alternate supply shall be 1,000 ltr/minute.
• Static tank water should be easily accessed by fire engines by way of sufficient manholes provided in the tank.
• Domestic tank connected to the static tank should have an overflow discharge capacity of 2250 liters per minute to a visible drain point.
• Suction of domestic supply must be fed through an overflow from static tank to avoid stagnation of water, maintaining the minimum capacity required.
• Fire brigade collecting breaches (4 nos) 63-m.m. Dia. Two of which should be for pump of 1400 ltrs/min capacity shall be provided to static tanks.
• Instantaneous male inlet arrangement in the valve box at a suitable place & connected to stsic tank by fixed pipe not less than 15 cm. dia. To discharge water at 2250 ltrs/min shall also be made to facilitate fire brigade
• Automatic sprinklers-emulsifying system
• Automatic sprinklers
• These shall be installed in basements/car parks if the area exceeds 500 sq.m.
• Any room or compartments of high rise building exceeding 500 sq.m.
• Shops and department stores exceeding an area of 750 sq.m.
• Warehouse & godowns as considered necessary.
• All floors of mixed occupancy, which can constitute hazard & is not provided with independent staircase.
• Emulsifying system
• Automatic high-pressure water spray emulsifying system shall be provided to protect transformers of a sub-station in basements.
• Foam generating system
• The system should be provided for protection of ancillary storage of oils or flammable liquids in basements.
• Gas suppression system
• This system shall be provided as per is:6382 code to all such places where water or foam cannot be used for extinguishing fire because of special nature of the contents.
• Lightning protection system
• Lightning protection system shall be installed in accordance with the provisions of part iii of national building code of India.
• Fire alarm system
• All business and industrial buildings shall be equipped with manually operated electrical fire alarm system with one or more call boxes located at each floor.the call boxes shall be located such that one or other of them shall be accessible to all occupants of the floor without having to travel more than 22.5 meters
• The call boxes shall be of the ‘break glass type’ without moving parts where the call is transmitted automatically to the control room.
• All call boxes shall be wired in a close circuit to the control panel at the control room,which should be located on the entrance of the building.the indication of the floor number where the call box is actuated could be seen on the control panel.the circuit should also have battery back up of 48 hours capacity working at full load and shall be arranged to trickle charge continuously from electrical mains.
• The call boxes shall be arranged to sound one or more sounders so as to ensure all occupants of the building are warned whenever any call box is actuated
• The call boxes shall be so installed that they do not obstruct the exit way and yet the location can be noticed from either direction.the base of the call box shall be at a height of 1 meter from the floor level.
• In addition to this ,automatic floor alarm system i.e.heat/smoke sensitive type detectors shall be installed as per the area and occupancy in buildings exceeding 24 meters height and should be in accordance with is:2189 code of practice.
• Control room
• All buildings mentioned in regulation “14” except residential buildings shall have a control room, on the entrance floor of the building with communication/public address system to all floors along with details of fire fighting equipment's and installations. The control room should also have facility to detect fire on any floor through the main control panel. The control room shall be manned round the clock. The control room should also have a fire axe.
• Fire drills & fire orders
• Fire notices/orders shall be displayed prominently int the building indicating the requirements of fire fighting & evacuation int the event of fire or other emergencies. All the occupants of the building shall be thoroughly familiarized with the contents and action needed in the event of an emergency.

 

[Pankaj Sharma]

Nice post sir