fire detection and alarm system


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  • fire detection and alarm system

    1. 1. FIRE DETECTION & ALARM SYSTEM <ul><li>RAVI SHANKAR SINGH </li></ul><ul><li>(E6S304) </li></ul>
    2. 2. Why are fire detection and alarm systems required? <ul><li>Detect fire in the areas. </li></ul><ul><li>Notify building occupants to take evasive action to escape the dangers of a hostile fire. </li></ul><ul><li>Summon organized assistance to initiate or assist in fire control activities. </li></ul><ul><li>Initiate automatic fire control & suppression systems & to sound alarm. </li></ul><ul><li>Supervise fire control & suppression systems to assure operational status is maintained Initiate auxiliary functions involving environmental, utility & process controls </li></ul><ul><li>Systems may incorporate one or all of these functions </li></ul>
    3. 3. Block diagram of FDA system Input Devices Output Devices Control Panel
    4. 4. Input Devices <ul><li>Fire Box (Manual Pull Station) </li></ul><ul><ul><li>When shorted trips an alarm (usually fire) </li></ul></ul><ul><ul><li>Installed in the normal exit path </li></ul></ul><ul><li>Types of Fire Box </li></ul><ul><ul><li>Single Action </li></ul></ul><ul><ul><ul><li>Pull handle once </li></ul></ul></ul><ul><ul><li>Glass Break </li></ul></ul><ul><ul><ul><li>Glass rod or plate is broken </li></ul></ul></ul><ul><ul><li>Double Action </li></ul></ul><ul><ul><ul><li>Lifting of a cover or opening a door </li></ul></ul></ul>
    5. 5. <ul><li>3.1) Heat detectors </li></ul><ul><ul><li>fixed temp type heat detector </li></ul></ul><ul><ul><li>rate-of-rise type heat detector </li></ul></ul><ul><li>3.2) Smoke detectors </li></ul><ul><ul><li>Photoelectric </li></ul></ul><ul><ul><li>Ionization </li></ul></ul><ul><li>3.3) Flame detectors </li></ul><ul><ul><ul><li>Ultraviolet light (UV) </li></ul></ul></ul><ul><ul><ul><li>Infrared (IR) </li></ul></ul></ul><ul><li>3.4) Fire-gas detectors </li></ul>FIRE DETECTORS Input Devices Heat Detectors Smoke Detector
    6. 6.
    7. 7. Fixed temp. heat detectors <ul><li>Detect heat by one or more of 3 primary principles of physics: </li></ul><ul><li>Expansion of heated material </li></ul><ul><li>Melting of heated material </li></ul><ul><li>Changes in resistance of heated material </li></ul>
    8. 8. Rate-of-rise heat detectors <ul><li>Operate on the principle that the temperature in a room will increase faster from fire than from atmospheric temperature </li></ul><ul><li>Will initiate an alarm when the rise in temp. exceeds 12-15F (7-8C) per minute </li></ul><ul><li>Alarm can be initiated at a temp. far below that required for a fixed-temp. device </li></ul><ul><ul><ul><ul><li>Reliable devices, not subject to false activations </li></ul></ul></ul></ul><ul><ul><ul><ul><li>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) </li></ul></ul></ul></ul><ul><li>Pneumatic rate-of-rise spot detector </li></ul><ul><li>Pneumatic rate-of-rise line detector </li></ul><ul><li>Thermoelectric detector </li></ul>
    9. 9. <ul><ul><li>Photoelectric smoke detector </li></ul></ul><ul><ul><li>Uses a photocell coupled with a specific light source. </li></ul></ul><ul><ul><li>Basically smoke entering the smoke detector chamber disrupts the light beam causing an alarm signal to be initiated </li></ul></ul><ul><ul><li>More sensitive to smoldering fires </li></ul></ul>1: optical chamber 2: cover 3: case moulding 4: Photodiode (detector) 5: infrared LED
    10. 10. Circuit of Photoelectric Smoke Detector
    11. 11. <ul><ul><li>Ionization smoke detector </li></ul></ul><ul><ul><li>Invisible products of combustion enter the chamber decreasing the current between the –ve & +ve plates, thereby initiating an alarm signal. </li></ul></ul><ul><ul><li>Generally responds faster to flaming fires versus smoldering fires </li></ul></ul><ul><ul><li>Automatically resets when the atmosphere clears </li></ul></ul>
    12. 12. Fire-gas detectors <ul><li>Monitors levels of carbon dioxide and carbon monoxide (common to all fires) </li></ul><ul><li>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 </li></ul><ul><li>Not many in use – very specialized applications </li></ul>
    13. 13. Combination detectors <ul><li>Single device can be designed to have more than 1 function eg. heat/smoke, smoke/carbon monoxide detectors </li></ul><ul><li>Different combination make the detectors more versatile and more responsive to fire conditions </li></ul>
    14. 14. Selection of Detectors for different Area S.No PLANT AREA TYPE OF DETECTORS 1. Main control room, Computer room, Electronic cubicle room and control rooms in outlying 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 detector with fixed temperature setting. 5. Cable gallery Combination of Optical type smoke detectors and Linear heat sensor running 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. detector with fixed element
    15. 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 detector will be cross zoned to actuate 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, H 2 generating plants and hydrogen storage areas. Flame proof rate of rise of temperature detector with fixed element and flame proof MCP
    16. 16. Audible Output Devices <ul><li>An audible alarm signal lets people know the alarm system has been activated </li></ul><ul><li>Devices may be mounted inside or outside based on level of protection required </li></ul><ul><li>May consist of: </li></ul><ul><ul><li>Sirens </li></ul></ul><ul><ul><li>Bells </li></ul></ul><ul><ul><li>Buzzers </li></ul></ul><ul><ul><li>Horns </li></ul></ul><ul><ul><li>Voice Drivers </li></ul></ul>Output Devices
    17. 17. Visual Output Devices <ul><li>A visual signal lets users know the status of the alarm system if activated </li></ul><ul><li>Visual devices may be mounted inside or outside </li></ul><ul><li>May consist of... </li></ul><ul><ul><li>Strobe lights </li></ul></ul><ul><ul><li>LED’s </li></ul></ul><ul><ul><li>On / Off site printer </li></ul></ul>Output Devices
    18. 18. Criteria to determine layout of the fire detectors <ul><li>The design, construction and operational features of all types of detectors shall be in accordance with relevant standards. </li></ul><ul><li>The number of fire detectors to be installed is governed by </li></ul><ul><ul><ul><li>total area to be protected </li></ul></ul></ul><ul><ul><ul><li>type of building construction </li></ul></ul></ul><ul><ul><ul><li>air movement & air velocity </li></ul></ul></ul><ul><ul><ul><li>ceiling obstructions </li></ul></ul></ul><ul><ul><ul><li>concentration of equipment in the area covered </li></ul></ul></ul><ul><ul><ul><li>sensitivity required </li></ul></ul></ul><ul><li>Area is divided into zones to be protected </li></ul><ul><li>The zones of individual detectors should overlap and no blind zone should be left. </li></ul>
    19. 19. <ul><li>Areas above false ceiling and below false flooring shall be considered as separate zones. </li></ul><ul><li>Under ideal conditions of smooth ceiling and average room size, one detector is recommended to protect the area. </li></ul><ul><li>Ionisation type detectors should be located where the largest combustible gas concentration can be expected. </li></ul><ul><li>In the air conditioned areas both ionisation and optical type smoke detectors are used. </li></ul><ul><li>Detectors must always installed at the highest point of the ceiling and minimum coverage indicated by manufacture shall be considered. </li></ul><ul><li>The number of detectors and their location should be so selected that complete coverage is obtained </li></ul>
    20. 20. Initial quantity estimation of smoke / heat detectors <ul><li>35 to 40 sq.m per detector for general application. </li></ul><ul><li>20 to 25 sq.m per detector for main control room, electronic cubicle room, computer room, etc., in view of high valve concentration </li></ul><ul><li>The exact requirement shall calculated based on relevant IS/NFPA standard </li></ul>
    21. 21. TYPES OF FIRE DETECTION SYSTEM <ul><li>Conventional FDA System </li></ul><ul><li>µ-P Based Addressable FDA System </li></ul>
    22. 22. CONVENTIONAL FIRE DETECTION AND ALARM SYSTEM <ul><li>Conventional fire sensors and manual call points shall provide for continuous surveillance the area. </li></ul><ul><li>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. </li></ul><ul><li>Repeater panel shall be located in security house / fire station to alert fire fighting / security personnel. </li></ul><ul><li>Fire detectors shall be selected depending on the type of fire expected in a particular area. </li></ul>
    23. 23. <ul><li>All the fire alarm circuits shall be of modular design using electronic printed card circuits to facilitate easy replacement. </li></ul><ul><li>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. </li></ul><ul><li>the alarm / system resetting shall be by common push button and not by individual switches for different zones / detectors. </li></ul>
    24. 24. Addressable Fire Detection & Alarm System <ul><li>It is an automatic fire detection & alarm system consists of fire detectors & manual call points positioned in Zones/ loop through out a building(Area). </li></ul><ul><li>These are wired to control & indicating equipment which shows the location of alarm call, & actuates audible alarm sounders. </li></ul><ul><ul><li>Industrial/ Non Industrial Buildings </li></ul></ul><ul><ul><li>Institutional Buildings </li></ul></ul><ul><ul><li>Residential Apartments </li></ul></ul><ul><ul><li>Hotel & Hospitals </li></ul></ul><ul><ul><li>All Industries </li></ul></ul><ul><ul><li>Mall & Multi Storied Complexes </li></ul></ul><ul><ul><li>Offices & Control Rooms </li></ul></ul>
    25. 25. Addressable µ-P based FDA system <ul><li>Addressable I/P devices </li></ul><ul><li>Addressable O/P devices </li></ul><ul><li>Control panel </li></ul><ul><li>Constant power supply </li></ul><ul><li>Emergency Battery supply </li></ul>
    26. 26. Microprocessor Based control Panel <ul><li>Processor(CPU) </li></ul><ul><li>Adequate number of loop modules for detector loops </li></ul><ul><li>A coloured VDU monitor with keyboard </li></ul><ul><li>Output modules for alarm </li></ul><ul><li>Output control & interlocks </li></ul><ul><li>Communication modules for interfacing </li></ul>
    27. 27. <ul><li>Continuous supervision of the detector connecting lines, individual detector performance / operation and disconnection / removal of detectors. </li></ul><ul><li>Discrimination between a real fire and false fire conditions by incorporating signal verification and other features. </li></ul><ul><li>Individual detector addressing capability. </li></ul><ul><li>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. </li></ul><ul><li>Pre-alarm in case of any detector / detectors requiring maintenance. </li></ul><ul><li>Facility shall be provided for alteration programme according to needs. </li></ul>BENEFITS OF µ-P BASED ADDRESSABLE FDA SYSTEM
    28. 28. CLEARANCE AND APPROVALS <ul><li>All detectors and sensors shall be approved by any of the following bodies as applicable : </li></ul><ul><ul><ul><li>Under writers’ Laboratories (UL) – USA </li></ul></ul></ul><ul><ul><ul><li>Fire Officers Committee (FOC) – UK </li></ul></ul></ul><ul><ul><ul><li>Any other internationally recognised body acceptable to Purchaser / Consultant. Approval certificates shall be furnished with the bid. </li></ul></ul></ul>
    29. 29. <ul><li>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. </li></ul><ul><ul><ul><li>Tariff Advisory Committee (TAC) of the Insurance Association of India. </li></ul></ul></ul><ul><ul><ul><li>Dept. of Atomic Energy (DAE) Certification of safety from radioactivity. </li></ul></ul></ul><ul><ul><ul><li>Central Building Research Institute (CBRL), Roorkee </li></ul></ul></ul><ul><ul><ul><li>Central Mining Research Station (CMRS), Dhanbad. </li></ul></ul></ul><ul><ul><ul><li>Local Fire Authority. </li></ul></ul></ul>
    30. 30. SOME APPLICABLE STANDARDS <ul><li>Code of practice for selection, installation & maintenance of automatic fire alarm & detection system- IS-2189,BS-5839 PART1,ANSI-NFPA-72,FOC RULES </li></ul><ul><li>Code of practice for fire safety of buildings - IS-1646 </li></ul><ul><li>Smoke detectors for use in automatic fire alarm system-IS-11360, BS-5445 PART-7, ANSI-UL268 </li></ul>