FIRE SERVICES

BY-MAYANK AGARWALMRIGANK MISHRAVIVEK BAGHOTIA

Purpose of fire alarm system:

Afire alarm system may be required in a building for one or both of the following purpose: To enhance the safety of the occupants’ by enabling an alarm of

fire to be given to persons in he building so that they may escape to safety and to enable other emergency actions to be taken.

The provision of such a system may be a legislative requirement and the system may be requiring the approval of the fire authority. To reduce the loss of property in a fire by the early detection of fire

and by summoning aid or activating fire fighting resources. The provision of such a system may be related to the cost of insuring the property and would then require the insurer’s approval.

Protection Of Life: Fire can kill and maim in many ways, e.g. by asphyxiation, irradiation, poisoning or burning.

However most accidental fires begin with smoldering and the evolution of smoke and other combustion products, and it is known that in most fires the phenomenon that first threatens human life is the loss of visibility on escape routes. It has been shown that people are unwilling to walk through smoke in which they cannot see further than 10m even though this in itself constitute no great hazard. If escape routes are not used for this or any other reason, the occupant are trapped, perhaps to be killed later in one of the ways mentioned above. A satisfactory fire alarm system will sound an alarm of fire while sufficient remains for extinction of the fire or escapes of the occupants before the escape routes become unusable because smoke or other combustion products.

Primary attention is paid in this code consequently to the protection of the escape routes by the provision of detectors both on the routes and in those areas from which the routes mighty are hazarded. An alarm of fire should be given before the visibility falls below about 20 m, in order of action to be taken before the escape routes become blocked by smoke. An important feature of the threat posed to human life by fire is that because of the strong convection movement produced by fire, the lethal combustion products may travel a long way from the seat of the fire to regions where people have not been alerted.

Protection Of Property:

A fire alarm system, although it can do nothing to reduce the incidence of fire, can help to reduce the resultant loss by reducing the delay between ignition and the start of effective fire fighting actions.

The longest delay is likely when no people are present in the early stage of the fire. For the reduction of property loss, therefore, automatic detection is essential, although manual call points should also be provided because when people are present they may give the first alarm of fire.

COMMUNICATION WITH THE LOCAL AUTHORITY FIRE BRIGADE:

It is desirable that provision should be made for the transmission of alarms to the local authority fire brigade by the speediest and most certain means available. Consultation with the insurers advisable.

 

If a building is divided into separate occupancies tenants or occupiers should make reliable arrangements to avoid the unnecessary duplication of emergency calls and, more importantly, to prevent the possibility of failure to call the fire brigade.

 

If communication with the local authority fire brigade is by means of telephone, care should be taken that the operation of fire alarm and fault warning sounders does not interfere with telephone speech.

 

If a special telephone is provided for emergency purposes, it should be arranged so that outgoing calls have priority or incoming calls are bared.

 

If the transmission of an alarm to the local authority fire brigade depends on a telephone operator on the premises making a call, consideration should be given to the possible effect of a fire on the operator.

TYPES OF FIRE DETECTORS:

General, Fire detector are designed to detect one or more of threat characteristic of a fire; smoke, heat or radiation (flames). No one type of detector is the most suitable for all applications and the final choice will depend on individual circumstances. In some premises it may be useful to combine different types of detectors or to install an extinguishing system either combined with or separate from an automatic alarm system.

All fire detectors will respond to some extent to phenomena other than fire.

A combination of various types of detectors may be necessary. The likely fire behavior of the content of each part of the building, the processes taking place and the design of the building should be considered. The susceptibility of the contents to heat, smoke and water damage should also be considered.

 

Heat and smoke detectors are suitable for use in most building. Radiation (flame) detectors are mainly suitable for supplementing heat and smoke detectors in high compartments, provided that an unobstructed view is possible, and for special applications such as outdoor storage and chemical processes employing flammable liquids.

 

The choice of fire detector may also be effected by the environmental conditions within the premises. In general, heat detectors have a greater resistance to adverse environmental conditions than other types have.

HEAT DETECTORS:

Fixed temperature heat detectors are less suitable where ambient temperatures are low or may vary slowly over wide range. Combined fixed temperature and rate-of-rise heat detectors are less suitable where the ambient temperature may vary rapidly over short periods. Where very high temperature are likely to be encountered, heat detectors complying with the requirements BS5445: Part 8should be used.

 

Heat detectors are not usually suitable for the protection of places where large losses could be caused by small fires, e.g. computer rooms. Before final selection of a detector, an estimate should be made of the likely extent of the damage caused before operation of the heat detector.

 

SMOKE DETECTORS:

Ionization chamber smoke detectors respond quickly to smoke containing small particles normally produced in clean burning fires, but may respond slowly to optically dense smoke, which may be produced by smoldering materials. Certain materials e.g. PVC, when overheated produces mainly large particles to which ionization detectors are less sensitive. Optical smoke detectors respond quickly to smoke that is optically dense. Both types of detectors have a sufficiently wide range of response to be of general use.

RADIATION (FLAME) DETECTOR):

Radiation (flame) detectors are suitable for use in special applications such as the general surveillance of large open areas in warehouses or timber yards or the local surveillance of critical areas where fire may spread very rapidly, e.g. at pumps, valves, pipework containing flammable liquids.

FIRE PROTECTION AND SAFETY GUIDELINES

As Stated in Bye Laws: No building shall be erected so as to deprive

any other building of the means of access.

For multi-storeyed build ings which are more than 15 m height: The width of the main

street on which the building abuts shall

not be less than 9 meters

A building shall abut on a spaces

directly connected from

the street by a hard surface

approach road, width of which is

not less than 9 meters

If there are any bends or curves on the approach road, a sufficient width shall be provided at the curve to enable the fire appliances to turn, the

turning circle being atleast of 9.0 m radius

The approach road to the building and open spaces on its all sides shall be upto 6 m widthand of hard surface capable of taking the weight of Fire engine

Main entrances to the premises shall allow easy access to the fire engine.

If archway is provided over the main entrance the height of the archway shall not be at a height less than 4 m

For multi-storeyed group housing schemes on one plot, the approach

road shall be 9 m in width and between individual buildings; there

shall be a space of 6 m around.

ACCESS TO BUILDING AS PER NFPA 5000

ACCESS > 50’

>50’

ACCESS SHALL PROVIDE ENTRANCE TO INTERIOR

ACCESS FOR NON SPRIKLERED BUILDING OF HT. > 40’

VEHICULAR ACCESS TO EACH COMPARTMENT OF BUILDING

ACCESS (THROUGH ALL WEATHER SURFACE) >=20’

>20

VEHICULAR ACCESS DIRECTLY OPPOSITE TO ENTRY

ACCESS MINIMUM 30’ WIDE TO EACH COMPARTMENT

FOR INCREASE IN HEIGHT OF 1’ ABOVE 30’ – INCREASE ACCESS BY 1’UPTO A HEIGHT OF 60’

Minimum dimension of Access Door

= 3’ x 8’6” Minimum dimension of Access

Window = 24”high x 20 “wide Minimum Clear Opening = 57 sq ft Minimum Sill Height = 44 in

CASE STUDY 1

CITY CENTRE AT NEW TOWN , KOLKATA

MIXED USE PROJECT

• SHOPS : 39876 SQ. M.

• HOTEL : 118 ROOMS (32 SQM. )

• MULTIPLEX: 4 CINEMA HALLS (240 PEOPLE CAPACITY)

TRANSVERSE SECTION

NATIONAL BUILDING CODES

CLASSIFICATION OF BUILDINGS BASED ON OCCUPANCY

Group A Residential (A-5)Group B EducationalGroup C InstitutionalGroup D AssemblyGroup E BusinessGroup F Mercantile (F-2)Group G lqdustrialGroup H StorageGroup J Hazardous

Fire Extinguishing method:

•AUTOMATIC SPRINKLER SYSTEM

•FIRE HYDRANT SYSTEM

AUTOMATIC SPRINKLER SYSTEM - An arrangement of piping, sprinklers and connected equipment designed to operate automatically by the heat of fire and to discharge water upon that fire and which may also simultaneously give automatic audible alarm.

FIRE HYDRANT SYSTEM - Hydrants are invariably used for fire fighting purposes to derive waterfrom the water line.

AUTOMATIC SPRINKLER SYSTEM

• Wall mounted side sprinkler (20 mm dia)

• Ceiling mounted top sprinkler (20 mm dia)

According to the occupancyLight hazard class (hotel)

Moderate hazard class (shops and parking in the basement)

Light Hazard class Maximum area coverage per sprinklera) Sidewall sprinklers 17 m2b) Other types of sprinklers 21 m2 Maximum distance between sprinklers on range pipes and between

adjacent rows of sprinklers:a) Sidewall sprinklers 4.5 mb) Other types of sprinklers 4.5 m

Moderate Hazard class Maximum area coverage per sprinklera) Sidewall sprinklers 17 m2b) Other types of sprinklers 21 m2 Maximum distance between sprinklers on range pipes and between adjacent rows of

sprinklersa) Sidewall sprinklers 3.4mb) Other types of sprinklers :With standard spacing :4.0 mWith staggered spacing :Sprinklers on ranges 4.6 m Adjacent rows 4.0 mMINIMUM DISTANCE BETWEEN 2 SPRINKLERS 2.0M

According to NBC any building exceeding 24 m in height has to conform to following requirements for pump capacity:

UNDERGROUND FIRE FIGHTING WATER TANK

Fire Detection system : Heat and Smoke Detector

The smoke detectors used in this building are Ionization chamber smoke detector. These respond quickly to invisible smoke from a clear burning fire, but may respond slowly to optically dense smoke.This type of detector can be used only in dust free and humidity controlled atmospheres. False alarms may be caused by smoke and other fumes, dusts.

FIRE ESCAPES

RESIDENTIAL (A-5) 22.5M

MERCANTILE (F-2) 30.0M

According to NBC :

•WIDTH 1.5M

•TREAD 250mm (residential blds)

300mm (other buildings)

•RISER max. 190mm (resi. Blds)

150mm (other buildings)

•Max. 15 stairs per flight

Fire staircases

DETAIL OF FIRE HYDRANT CABINET

CASE STUDY 2

ABOUT THE PROJECT

NAME OF PROJECT - SANDY RESORT

TYPE - HOTEL

SITE - BHUBANESHWAR ( ORISSA )

ARCHITECT - NCPL ( NIRMAN CONSULTANTS PVT. LTD. )

BUILDING BLOCKS - THREE ( BLOCK – A ,B & C)

SITE AREA - 15136.69 SQ. M.

YEAR - 2008

NO OF USERS - APPROX. 500

BLOCK A - G FLOOR

BLOCK B - G+1

BLOCK C - G+5

AREA SPECIFICATION

FIRE FIGHTING

1) EXTERNAL FIRE FIGHTING

COMPONENTS :

• WATER - FIRE TANK STP RWH

• PUMP ROOM

• FIRE EXTERNAL RING

• FIRE HYDRANTS

•FIRE EXTERNAL RING – 150 MM DIA.

• FIRE TANK - CAP. 150 cub. M.

2) INTERNAL FIRE FIGHTING

COMPONENTS :

• WATER - EXTERNAL SOURCE

• FIRE EXTINGUISHERS

• FIRE HYDRANT

• HOSE REEL

• FIRE EXIT

FIRE SHAFT – 1) FIRE EXTINGUISHER 2) FIRE HYDRANT 3) HOSE REEL • NOTE- EVERY ROOM HAS PORTABLE FIRE

EXTINGUISHER AS PER REQUIREMENT

CASE STUDY 3

IFCI Towers Architect :Raja Aederi Total height of 87.5 m

including the 2 basements & terrace tanks. (76+7+1.5+3)m

Building is in air-traffic funnel corridor.

Project completed in record time of 2 years

Office Building at Nehru Place, New Delhi Occupancy of 800 people (approx) Centrally air-conditioned building with fixed glass

curtain walling with façade area of 6000 sq.m. 6 mm thick single fixed heat reflective glass with 78%

reflectance

FIRE FIGHTINGProvision of a fire control room at lower ground floor lvlThe bldg has been divided into 4 equal fire zones The building also has 3 refuge areas (2.5 m wide) connected

through the staircases The lift lobby area is not pressurized but is protected by a system

of water curtains all around it.All the lifts have a fire man switch and only the service lift is

pressurized3 wet risers shafts (0.6m x0.9m) have been providedSprinklers systems (melting point temp 60 oC), smoke detectors

and fire detectors provided all through the floor areas

FIRE FIGHTING

Fire refuge areas connected to staircases

FIRE FIGHTING Provision of CO2 flooding system for

the DG set rooms, HT Room, LT Room, Transformer Room and all electrical rooms.

Provision of hooters for warning which come on automatically in case of fire alarm

The hooters have been connected with the blowers which starts automatically in case of emergency. They pressurize the stairwells and other refuge areas

Fire pumps and fire hoses have been provided in the outside landscaped of the bldg

CASE STUDY 4

Global Business Park

Architects: HOK & Bose, USA.Associate Architects: Sikka AssociatesDevelopers : S.B. Developers Pvt. Ltd.Marketed by: UNITECH, Gurgaon and Vipul

Developers.

EAST ELEVATION

Located on Mehrauli-Gurgaon Road, 1.5 km away from GurgaonAreas:Total Site Area: 17 acres approximately.Office Towers: A, BBoth towers are G + 9 with 2 basement parkingTotal GFA of Tower A&B: 5.7 Acres

N

AHU

AC PLANTSECURITY & FIRE CONTROL ROOL

ELECTRIC ROOM

TOILETS

AHU

ELECTRIC ROOM

STAIRCASE

TOILETS

LIFTS

OVERHEAD WATER TANK

Tower A:

2 stair case one at the periphery and one at centre

4 passenger lift(2 16 Passengers and 2 10 Passengers) and 1 service lift

All the four lifts begin from lower basement and run up to 9th floor

Service lift begins at upper basement

At ground floor this staircase has an exit on the external wall.

Tower B:

2 staircase

3 lifts(16 passengers each) and 1 service lift.

Upper basement to 9th floor

1 of these passenger lifts starts from lower basement, rest all start from ground floor

The peripheral staircase of begins from ground floor

Stair case begins at lower basement

At ground floor this staircase has an exit on the external wall.

Fire Fighting The fire fighting system deployed in Global Business Park is Wet Riser cum Down

Comer which is in accordance with requirements of NBC.

Wet riser-cum-down comer is an arrangement for fire fighting within the building by means of vertical rising mains no less than 100 mm internal dia with hydrant outlets and hose reel on each floor/ landing connected to a terrace tank for fire fighting purpose, through a booster pump, check valve and a non-return valve near the tank end and a fire pump, gate and non-return valve, over the underground static tank. A fire service inlet at ground level fitted with a non-return valve shall also be provided to the rising main for charging it by fire services pump in case of failure of static fire pump over the underground static tanks.

Underground Tank : 3,00,000 lts.( single tank for both tower A tower B)

Over-head Tank : 60,000 lts.( for a single tower, each tower having their separate towers on the terrace)

AUTOMATIC SPRINKLER SYSTEM - An arrangement of piping, sprinklers and connected equipment designed to operate automatically by the heat of fire and to discharge water upon that fire and which may also simultaneously give automatic audible alarm.

Wet riser pipe

Pressure bulb type sprinkler

Fire Extinguishing method: Automatic sprinkler system

GROUND FLOOR PLAN

FIRE HAZARD IN MADRID,SPAIN

Windsor Tower Madrid, Spain

The Windsor Tower (in Spanish Torre Windsor) was built in 1979 in the financial center of Madrid, Spain.

106 meters high and had 32 floors of which 29 were above ground level and 3 below

Overview of event.

Location:Madrid, Spain

Fire Event:12 February 2005Fire started at the 21st Floor, spreading to all floors above the 2nd Floor.

Fire duration: 18 ~ 20 hours

Fire Damage:Extensive slab collapse above the 17th Floor. The building was totally destroyed by the fire.

The Damage

The Windsor Tower was completely gutted by the fire on 12 February 2005. A large portion of the floor slabs above the 17th Floor progressively collapsed during the fire when the unprotected steel perimeter columns on the upper levels buckled and collapsed (see Figure 1). It was believed that the massive transfer structure at the 17th Floor level resisted further collapse of the building.

The whole building was beyond repair and had to be demolished. The estimated property loss was €72m before the renovation.

Analysis

The main factors leading to the rapid fire growth and the fire spread to almost all floors included:

1. the lack of effective fire fighting measures, such as automotive sprinklers

2. the “open plan” floors with a floor area of 1000m2 3. the failure of vertical compartmentation measures, in the façade

system and the floor openings4. lack of fire stops between the curtain wall façade and the concrete

floor slabs

It was believed that the multiple floor fire, along with the simultaneous buckling of the unprotected steel perimeter columns at several floors, triggered the collapse of the floor slabs above the 17th floor. The reduced damage below the 17th floor might provide a clue.

Existing Passive Fire Protection Measures

• Floor by floor compartmentation (typical compartment size 850 m2) •An unspecified fire resistance period for the concrete structure, steel columns protected below 17th Floor, unprotected above that level. •Vertical shafts forming separate compartments

•1.0m or 1.5m deep vertical fire protection along the perimeter slab edge.

Lessons to be learnt

Procedures to ensure early call out to the Fire Brigade

Provisions for speedy access to the fire floor via protected fire fighting lifts and use of wet risers

Effective compartmentation measures, including sprinkler protection for high-rise buildings

Good coordination of fire safety measures with refurbishment works and programme, especially in an occupied building

Holistic Fire safety measures

Fire safety with respect to three components:

Means of escape. Control of fire spread (both internal and external to the building). Access and facilities for fire fighting

All aspects of fire safety are interrelated and each one is dependent on three main variables: the buildings’ function, situation and size.

Structural fire protection measures must fulfill three main aims: Personal protection to preserve life and health Protection of property Environmental protection to minimize adverse effects of toxic gases and

smoke

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