Fire Bye Laws

8/6/2019 Fire Bye Laws

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FIRE BYE LAWS

Purpose :

Before we undertake design of any system it is imperative to know the guide-lines on thesubject issued by the deptt. and the regulatory bodies. The awareness of these guide lines willresult in proper system selection and its design.

OBJECTIVE :At the end of the session, the participant shall be able to :

(i) explain and use the national building code.

(ii) explain and use the B.I.S. code and

(iii) explain and used the Delhi Fire Bye-Laws

To the extent these are required for designing a Fire Protection and Fire-Fighting system.

INTRODUCTION :

State Govts. have published bye-laws which are to be adhered to when constructing ahigh rise building. Designer must obtain and study the fire bye laws applicable to the particulararea while planning. In this lecture we shall study the Fire-Bye-Laws as applicable to services inbuildings. We shall discuss the following :-

(i) Electrical Services.

(ii) Transformer Sub-stn.

(iii) Staircase and corridor lighting.

(iv) Air-Conditioning.

(v) Lift and Fire lift.

(vi) Alternate sources of electric supply.

(vii) Fire Alarm System.

ELECTRICAL SERVICE:

(a) The electric distribution cables/wiring shall be laid in a separate duct. The duct shall besealed at every alternative floor with non-combustible materials having the same fire resistanceas that of the duct. Low and medium voltage wiring running

(b) Water mains, telephone lines, inter-com lines, gas pipes of any other service line shall notland in the duct for electric cables.

(c) Separate circuits for water pumps, lifts Staircases and corridor lighting and blowers forpressurising system shall be provided directly from the main switch gear panel and these circuitsshall be clearly labeled.


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R. Sharma (BSNL Electrical Zone Patna)

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(d) The inspection panel doors and other opening in the shaft shall be provided with air-tightfire doors having fire resistance of not less than 2 hour.

(e) Medium and low voltage wiring running in shaft, and within false ceiling shall run in metalconduit. Any 230V wiring for lighting or other service, above false ceiling, shall have 660 Vgrade insulation. The false ceiling, including all fixtures used for its suspension, shall be of non-combustible material.

(f) An independent and well ventilated service from floor with direct access from outside orfrom the corridor for the purpose of termination of electric supply from the licensees serviceand alternative supply cables. The doors provided for the service room shall have fire resistanceof not less than 2 h.

(g) If the licensees agree to provide meters on upper floors, the licensees' cables shall besegregated from consumers' cable by providing a partition in the duct. Meter rooms on upperfloors shall not open into staircase enclosures and shall be ventilated directly to open air outside.

TRANSFORMERS:

Sub station or a switch-station with apparatus having more than 2000 liters of oil

shall not ordinarily be located in the basement where proper oil drainage arrangements cannotbe provided. If transformers are housed in the building below the ground level, they shallnecessarily be in the first basement in a separate fire resisting room of 4 h rating. The roomshall necessarily be in the first basement in a separate fire resisting room of 4 h. rating. Theroom shall necessarily be at the periphery of the basement. The entrance to the room shall beprovided with a fire resisting door of 2 h fire rating. A curb (sill) of a suitable height shall beprovided at the entrance in order to prevent the flow of oil from ruptured transformer into theother parts of the basement. Direct access to the transformer room shall be provided, preferablyfrom outside. The switch gears shall be housed in a room separated from the transformer baysby a fire resisting wall with fire resistance of not less than 4 h.

(b) The transformer, if housed in basement, shall be protected by an automatic high velocitywater spray system.

(c) In case the transformer are housed in the basement, totally segregated from other areas of thebasement by 4 h. fire resisting wall/walls with an access directly from outside, they may beprotected by carbon dioxide or BCF (Bromo-chloro-difluoro-methane) or BTM (Bromo-trifluoro-methane) fixed installation system.

(d) When housed at ground floor level, it/they shall be cut off from the other portion of premisesby fire resisting walls of 4 h fire resistance.

(e) Oil filled transformer shall not be housed on any floor above the ground floor.

(f) Soak pit of approved design shall be provided where the aggregate oil capacity of theapparatus does not exceed 2000 liters. Where the oil capacity exceeds 2 000 liters, a tank ofRCC construction of capacity capable of accommodating the entire oil of the transformers shallbe provided at a lower level to collect the oil from the catch-pit in case of emergency. The pipeconnecting the catch-pit to the tank shall be of non-combustible construction and shall beprovided with a flame-arrester.


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STAIRCASE AND CORRIDOR LIGHTING:

(a) The staircase and corridor lighting shall be on separate circuits and shall be independentlyconnected so that it could be operated by one switch installation on the ground floor easilyaccessible to fire fighting staff at any time irrespective of the position of the individual controlof the light points, if any. It should be of miniature circuit breaker type of switch so as to avoidreplacement of fuse in case of crisis.

(b) Staircase and corridor lighting shall also be connected to alternative supply for buildingexceeding 24 mt in height. For assembly , institutional buildings of height less than 24m., thealternative source of supply may be provided by battery continuously trickle charged from theelectric mains.

(c) Suitable arrangement shall be made by installing double throw switches to ensure that thelighting installed in the staircase and the corridor does not get connected to two source of supplysimultaneously. Double throw switch shall be installed in the service room for terminating thestand-by supply.

(d) Emergency light shall be provided in the staircase/corridor.

AIR-CONDITIONING :

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

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

(c) Wherever the ducts pass through fire walls or floor, the opening around the ducts shall besealed with fire resisting materials, such as asbestos rope, vermiculite concrete, etc.

(d) As far as possible, metallic ducts shall be used even for the return air instead of space abovethe false ceiling.

(e) The materials used for insulting the duct system (inside or outside) shall be of non-combustible materials. Glass wool shall not be wrapped or secured by any material ofcombustible nature.

(f) Area more than 750m Sq.mt. on individual floor shall be segregated by a fire wall andautomatic fire dampers for isolation shall be provided (see g).

(g) Air duct servicing main floor area, corridors etc., shall not pass through the staircaseenclosure.

(h) The air-handling units shall be separate for each floor and air ducts for every floor shall beseparate and in no way interconnected with the ducting of any other floor.

(j) If the air-handling units serves more than one floor, the recommendations given above shallbe complied with in addition to the condition given below :

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


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

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

(m) Where plenum is used for return air passage ceiling and its fixture shall be of no-combustible material.

(n) The air filters of the air-handling units shall be of non-combustible material.(p) The air-handling unit room shall not be used for storage of any combustible materials.

(q) Inspection panels shall be provided in the main trunking to facilitate the cleaning of ducts ofaccumulated duct and to obtain access for maintenance of fire dampers.

(r) No combustible material shall be fixed nearer than 15 c.m. ka any unless such duct isproperly enclosed and protected with non-combustible material (glass wool or spunglass withneoprene facing) enclosed and wrapped with aluminium sheeting at least 3.2mm. thick andwhich would not readily conduct heat.

FIRE DAMPERS :

(s) (1)These shall be located in conditioned air ducts and return air ducts/passages at thefollowing points :

(i) At the fire separation wall,

(ii) Where the ducts/passage enter the central vertical shaft,

(iii) Where the ducts pass through floors, and

(iv) At the inlet of supply air duct and the return air duct of each compartment on every floor.

(2) The dampers shall operate automatically and shall simultaneously switch off the air-handling

fans. Manual operation facilities shall also be provided.

Automatic fire dampers shall be so arranged so as to close by gravity in the direction of airmovement and to remain tightly closed upon operation of a fusible link.

LIFTS-GENERAL REQUIREMENTS :

(a) Walls of lift enclosures shall have fire rating of 2 h. lift shafts shall have a vent at the top ofarea not less than 0.2 Sq.mt.

(b) Lift motor room shall be located preferably on top of the shaft and separated from the shaftby the floor of the room.

(c) Landing doors in lift enclosures shall have a fire resistance of not less half an hour.

(d) The number of lifts in one lift bank shall not exceed 4. Individual shafts in a bank shall beseparated by a wall of 2 h fire rating.

(e) Lift car door shall have a fire resistance rating of 1 h.


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(vii) The speed of the fire lift shall be such that it can reach the top floor from ground levelwithin 1 min.

STAND BY POWER SUPPLY:

A stand-by electric generator shall be installed to supply power to staircase and corridorlighting circuits, fire lifts, the stand-by fire pump, pressurisation fans and blowers, smoke

extraction and damper system in case of failure of normal electric supply. The generator shall becapable of taking starting current of all the machines and circuits stated above simultaneously. Ifthe stand-by pump is driven by diesel engine, the generator supply need not be connected to thestand by pump. Where parallel HV/LV supply from a separate sub station is provided withappropriate of generator may be waived in consultation with the Authority.

FIRE ALARM SYSTEM :

All building with heights of more than 15m. Shall be equipped with manuallyoperated electrical fire alarm (MOEFA) system and automatic fire alarm system. However,Apartment and office building between 15m. and 24m. in height may be exempted from theinstallation of automatic fire alarm system provided the local fire brigade is suitably equipped

for dealing with fire above 15m. height and in the opinion of the Authority, such building doesnot constitute a hazard to the safety of the adjacent property or occupants of the building itself.

Manually operated electric fire alarm system shall be installed in a building with one or morecall boxes located at each floor. The call boxes shall conform to the following :

(a) The location of call boxes shall be decided after taking into consideration the floor plan witha view to ensuring that one or the other call box shall be readily accessible to all occupants ofthe floor without having to travel more than 22.5m.

(b) The call boxes shall be of the break-glass type where the call is transmitted automatically tothe control room without any other action on the part of the person operating the call box. Themechanism of operation of the call boxes shall preferably be without any moving part. However,

where any moving part is incorporated in the design of the call box, it shall be of an approvedtype so that there shall be no malfunctioning of the call box.

(c) All call boxes shall be wired in a closed circuit to a control panel in the control room inaccordance with good practice so that the number/zone where the call box is actuated is clearlyindicated on the control panel. The circuit shall also include one or more batteries with acapacity of 48 hour. normal working at full load. The battery shall be arranged to becontinuously trickle- charged from the electric mains. The circuit may be connected toalternative source of electric supply.

(d) The call boxes shall be arranged to sound one more sounders so as to ensure that allappropriate occupants of the desired floor(s) shall be warned whenever any call box is actuated.

(e) The call boxes shall be so installed that they do not obstruct the exit ways and yet theirlocation can easily be noticed from either direction. The base of the call boxes shall be at aheight of 1 mt. From the floor level.

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Fire Bye Laws