cdocumentsandsettingsdeedesktopfda-1-090226130600-phpapp01.ppt

7/27/2019 cdocumentsandsettingsdeedesktopfda-1-090226130600-phpapp01.ppt

1/30

FIRE DETECTION & ALARM SYSTEM

RAVI SHANKAR SINGH

(E6S304)

1


2/30

2

Why are fire detection and alarm systems

required?

Detect fire in the areas.

Notify building occupants to take evasive action to escape thedangers of a hostile fire.

Summon organized assistance to initiate or assist in fire controlactivities.

Initiate automatic fire control & suppression systems & to soundalarm.

Supervise fire control & suppression systems to assure operationalstatus is maintained Initiate auxiliary functions involving

environmental, utility & process controls

Systems may incorporate one or all of these functions


3/30

Block diagram of FDA system

3

Input

Devices

Output

Devices

Control

Panel


4/30

4

Input Devices

Fire Box (Manual Pull Station)

When shorted trips an alarm (usually fire)

Installed in the normal exit path

Types of Fire Box Single Action

Pull handle once

Glass Break

Glass rod or plate is broken

Double Action

Lifting of a cover or opening a door


5/30

5

3.1) Heat detectors

1. fixed temp type heat detector

2. rate-of-rise type heat detector

3.2) Smoke detectors

1. Photoelectric

2. Ionization

3.3) Flame detectors

1. Ultraviolet light (UV)

2. Infrared (IR)3.4) Fire-gas detectors

FIRE DETECTORS

Input Devices

Heat Detectors

Smoke Detector


6/30

6


7/30

Fixed temp. heat detectors

Detect heat by one or more of 3 primary principles of physics:

Expansion of heated material

Melting of heated material Changes in resistance of heated material


8/30

Rate-of-rise heat detectors

Operate on the principle that the temperature in a room willincrease faster from fire than from atmospheric temperature

Will initiate an alarm when the rise in temp. exceeds 12-15F (7-8C)

per minute

Alarm can be initiated at a temp. far below that required for a fixed-

temp. device

Reliable devices, not subject to false activations

But if not properly installed, they can be activated under non fire

conditions (eg. detector located too close to doorway and subject to

extreme fluctuations in temperatures)

Pneumatic rate-of-rise spot detector

Pneumatic rate-of-rise line detector

Thermoelectric detector


9/30

9

Photoelectric smoke detector

Uses a photocell coupled with a specific light source.

Basically smoke entering the smoke detector chamber disruptsthe light beam causing an alarm signal to be initiated

More sensitive to smoldering fires

1: optical chamber

2: cover3: case moulding

4: Photodiode (detector)

5: infrared LED


10/30

10

Circuit of Photoelectric Smoke Detector


11/30

11

Ionization smoke detector

Invisible products of combustion enter the chamber

decreasing the current between theve & +ve plates,

thereby initiating an alarm signal.

Generally responds faster to flaming fires versus

smoldering fires Automatically resets when the atmosphere clears


12/30

Fire-gas detectors

Monitors levels of carbon dioxide and carbon monoxide

(common to all fires)

More discriminating than other detectors can be designed to

be sensitive only to gases produced by specific types of hostile

fires and ignores gases produced by friendly fires

Not many in use very specialized applications


13/30

Combination detectors

Single device can be designed to have more than 1 function eg.

heat/smoke, smoke/carbon monoxide detectors

Different combination make the detectors more versatile and

more responsive to fire conditions


14/30

14

S.No PLANT AREA TYPE OF DETECTORS

1. Main control room, Computer

room, Electronic cubicle

room and control rooms inoutlying areas.

Combination of -

Ionisation smoke detector

Optical type smoke detector

2. Switchgear rooms in main

Plant and outlying areas,

battery charger room, record

and shift-in-charge engineers

room

Ionisation type smoke detector.

3. Office rooms / storage rooms Ionisation type smoke detector

4. Battery rooms and chemically

corrosive areas.

Corrosion resistant, Rate of rise of temperature heat

detectorwith fixed temperature setting.

5. Cable gallery Combination of Optical type smoke detectors and Linear

heat sensorrunning above all HV and LV power cable trays.

Unless the vertical distance between cable tray is less than

500 mm in which case alternate trays (in addition to the top

and bottom trays). The optical smoke detector and LHS

detectors along with necessary number of interface units in the

cable gallery will be cross zoned to actuate the water spray

system

6. Station building / Plant area Infrared flame detectors (where oil tanks are located), spray

tanks rate of rise of temp. detectorwith fixed element

Selection of Detectors for different Area


15/30

15

7. Coal Conveyors Analogue Linear heat sensor cable, infra red spark / ember

detectors and manual call points. If water spray system is

provided the LHS cable and IR detectorwill be cross zoned toactuate the same

8. Dusty areas in coal handling

plants like crusher house

Flame proof manual call points

9. Junction towers Flame proof heat detectors, flame proof manual call points

10. Conveyor tunnels Flame proof infrared detectors, flame proof MCPs, LHS

cables

11. Hazardous plant areas such

as fuel oil / lube oil, DG

houses, H2 generating plantsand hydrogen storage areas.

Flame proof rate of rise of temperature detector with fixed

element and flame proof MCP


16/30

16

Audible Output Devices An audible alarm signal lets people know

the alarm system has been activated

Devices may be mounted inside or outside

based on level of protection required May consist of:

Sirens

Bells

Buzzers

Horns

Voice Drivers

Output Devices


17/30

17

Visual Output Devices

A visual signal lets users know the status ofthe alarm system if activated

Visual devices may be mounted inside oroutside

May consist of...

Strobe lights LEDs

On / Off site printer

Output Devices


18/30

1

8

Criteria to determine layout of the fire detectors

The design, construction and operational features of all types of

detectors shall be in accordance with relevant standards.

The number of fire detectors to be installed is governed by

total area to be protected

type of building construction

air movement & air velocity

ceiling obstructions

concentration of equipment in the area covered

sensitivity required

Area is divided into zones to be protected

The zones of individual detectors should overlap and no blind zone

should be left.


19/30

19

Areas above false ceiling and below false flooring shall be

considered as separate zones.

Under ideal conditions of smooth ceiling and average room size, one

detector is recommended to protect the area.

Ionisation type detectors should be located where the largest

combustible gas concentration can be expected.

In the air conditioned areas both ionisation and optical type smoke

detectors are used.

Detectors must always installed at the highest point of the ceiling

and minimum coverage indicated by manufacture shall be

considered.

The number of detectors and their location should be so selected that

complete coverage is obtained


20/30

2

0

Initial quantity estimation of smoke / heat detectors

35 to 40 sq.m per detector for general application.

20 to 25 sq.m per detector for main control room, electronic

cubicle room, computer room, etc., in view of high valve

concentration

The exact requirement shall calculated based on relevant

IS/NFPA standard


21/30

TYPES OF FIRE DETECTION SYSTEM

A. Conventional FDA System

B. -P Based Addressable FDA System

2

1


22/30

CONVENTIONAL FIRE DETECTION AND ALARM SYSTEM

Conventional fire sensors and manual call points shall provide for continuous

surveillance the area.

Main fire alarm panel shall derive signals from the zone indicating panels and

audible and visual annunciation shall be provided in the event of fire. Repeater panel shall be located in security house / fire station to alert fire

fighting / security personnel.

Fire detectors shall be selected depending on the type of fire expected in a

particular area.

22


23/30

2

3

All the fire alarm circuits shall be of modular design using

electronic printed card circuits to facilitate easy replacement.

The system design shall be such that operation / resetting of

alarms for one zone / detector will not block availability of alarm

for any other zone.

the alarm / system resetting shall be by common push button andnot by individual switches for different zones / detectors.


24/30

24

Addressable Fire Detection & Alarm

System

It is an automatic fire detection & alarm system consists of firedetectors & manual call points positioned in Zones/ loop through

out a building(Area).

These are wired to control & indicating equipment which shows

the location of alarm call, & actuates audible alarm sounders.

Industrial/ Non Industrial Buildings

Institutional Buildings

Residential Apartments Hotel & Hospitals

All Industries

Mall & Multi Storied Complexes

Offices & Control Rooms


25/30

25

Addressable -P based FDA system

Addressable I/P devices

Addressable O/P devices

Control panel

Constant power supply

Emergency Battery supply


26/30

2

6

Microprocessor Based control Panel

Processor(CPU)

Adequate number of loop modules for detector loops

A coloured VDU monitor with keyboard

Output modules for alarm

Output control & interlocks

Communication modules for interfacing


27/30

27

Continuous supervision of the detector connecting lines, individual

detector performance / operation and disconnection / removal of

detectors.

Discrimination between a real fire and false fire conditions by

incorporating signal verification and other features.

Individual detector addressing capability.

Detection of over / under sensitive detectors and automatic calibration

by increasing or decreasing their sensitivity levels based on

environmental conditions like air movement, fumes, humidity, etc.

Pre-alarm in case of any detector / detectors requiring maintenance.

Facility shall be provided for alteration programme according to needs.

BENEFITS OF -P BASED ADDRESSABLE FDA

SYSTEM


28/30

CLEARANCE AND APPROVALS

All detectors and sensors shall be approved by any of the

following bodies as applicable :

A. Under writers Laboratories (UL) USA

B. Fire Officers Committee (FOC) UK

C. Any other internationally recognised body acceptable to

Purchaser / Consultant. Approval certificates shall be

furnished with the bid.

28


29/30

The Contractor shall be solely responsible for obtaining the

required approval and clearance for the different components

and systems of the fire detection and alarm system from the

following authorities as applicable.

A. Tariff Advisory Committee (TAC) of the Insurance Association of

India.

B. Dept. of Atomic Energy (DAE) Certification of safety from

radioactivity.

C. Central Building Research Institute (CBRL), Roorkee

D. Central Mining Research Station (CMRS), Dhanbad.

E. Local Fire Authority.

29


30/30

SOME APPLICABLE STANDARDS

Code of practice for selection, installation & maintenance of

automatic fire alarm & detection system-IS-2189,BS-5839

PART1,ANSI-NFPA-72,FOC RULES

Code of practice for fire safety of buildings - IS-1646

Smoke detectors for use in automatic fire alarm system-IS-11360,

BS-5445 PART-7, ANSI-UL268

3

0

cdocumentsandsettingsdeedesktopfda-1-090226130600-phpapp01.ppt

Documents

Transcript of cdocumentsandsettingsdeedesktopfda-1-090226130600-phpapp01.ppt