Introduction of AutoCAD

                                                            List of Figure:

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Content

Page No.

1.      Block Diagram of FDA System

2.      FIRE GROWTH AND BEHAVIOR

3.      Why are fire detection and alarm systems required?

4.      Input Devices

5.      Output Devices

6.      FIRE SPRINKLERS

7.      TYPES OF FIRE DETECTION SYSTEM

8.      Selection of Detectors for different Area

9.      BENEFITS OF μ-P BASED ADDRESSABLE FDA SYSTEM

1 .  Some applicable standards

. .Public Addressing system (PA System)

INTRODUCTION

A fire alarm system has a number of devices working together to detect and warn people through visual and audio appliances when smoke, fire, carbon monoxide or other emergencies are present. These alarms may be activated automatically from smoke detectors, and heat detectors or may also be activated via manual fire alarm activation devices such as manual call points or pull stations. Alarms can be either motorized bells or wall mountable sounders or horns. They can also be [(speaker strobes]) which sound an alarm, followed by a voice evacuation message which warns people inside the building not to use the elevators. Fire alarm sounders can be set to certain frequencies and different tones including low, medium and high, depending on the country and manufacturer of the device. Most fire alarm systems in Europe sound like a siren with alternating frequencies. Fire alarm electronic devices are known as horns in the United States and Canada, and can be either continuous or set to different codes. Fire alarm warning devices can also be set to different volume levels.

A key aspect of fire protection is to identify a developing fire emergency in a timely manner, and to alert the building's occupants and fire emergency organizations. This is the role of fire detection and alarm systems. Depending on the anticipated fire scenario, building and use type, number and type of occupants, and criticality of contents and mission, these systems can provide several main functions. First they provide a means to identify a developing fire through either manual or automatic methods and second, they alert building occupants to a fire condition and the need to evacuate. Another common function is the transmission of an alarm notification signal to the fire department or other emergency response organization.                                 

FDA System block Diagram

                                                                  

FIRE GROWTH AND BEHAVIOR

Before attempting to understand fire detection systems and automatic sprinklers, it is beneficial to possess a basic knowledge of fire development and behavior. With this information, the role and interaction of these supplemental fire safety systems in the protection process can then be better realized

Basically, a fire is a chemical reaction in which a carbon based material (fuel), mixes with oxygen (usually as a component of air), and is heated to a point where flammable vapors are produced. These vapors can then come in contact with something that is hot enough to cause vapor ignition, and a resulting fire. In simple terms, something that can burn touches something that is hot, and a fire is produced.

When the ignition source contacts the fuel, a fire can start. Following this contact, the typical accidental fire begins as a slow growth, smoldering process which may last from a few minutes to several hours. The duration of this "incipient" period is dependent on a variety of factors including fuel type, its physical arrangement, and quantity of available oxygen. During this period heat generation increases, producing light to moderate volumes of smoke. The characteristic smell of smoke is usually the first indication that an incipient fire is underway. It is during this stage that early detection (either human or automatic), followed by a timely response by qualified fire emergency professionals, can control the fire before significant losses occur.

A fire can have far reaching impact on the institution's buildings, contents and mission. General consequences may include:

·         Collections damage. Most heritage institutions house unique and irreplaceable objects. Fire generated heat and smoke can severely damage or totally destroy these items beyond repair.

·         Operations and mission damage. Heritage occupancies often contain educational facilities, conservation laboratories, catalogue services, administrative/support staff offices, exhibition production, retail, food service, and a host of other activities.

·         A fire can destroy walls, floors, ceiling/roof assemblies and structural support, as well as systems that illuminate, control temperature and humidity, and supply electrical power. This can in turn lead to content harm, and expensive relocation activities.

·         Knowledge loss. Books, manuscripts, photographs, films, recordings and other archival collections contain a vast wealth of information that can be destroyed by fire.

·         Injury or loss of life. The lives of staff and visitors can be endangered.

Why are fire detection and alarm systems required?

       1. Detect fire in the areas.

       2. Notify building occupants to take evasive action to escape the dangers of a hostile Fir

       3. Summon organized assistance to initiate or assist in fire control activities.

       4. Initiate automatic fire control & suppression systems & to sound alarm.

5.      Supervise fire control & suppression systems to assure operational status is

maintained Initiate auxiliary functions involving environmental, utility & process controls

6.      Alarm systems and fire service monitoring of these systems are required in certain types of buildings under legislation such as the National Construction Code of Australia.

7.      Alarm systems are primarily designed to warn occupants of a fire so they can safely evacuate the premises.

8. Correctly maintained and operating alarm systems are effective and proven life saving devices.

9. Fire alarm systems are important in providing occupants of buildings prompt warning if a fire occurs.

10. Systems that are not properly installed or maintained may cause unwanted alarm activations. This has a negative effect on occupants' responses to genuine alarms and as a result downgrades their effectiveness.

11. The MFS is concerned about the level of complacency within the community when an automatic fire alarm operates.

INPUT DEVICES

Mostly Three tyes of Input Devices are used to trigger alarm:

1.Fire alarm pull station(Fire Box):

                                       A fire alarm pull station is an active fire protection device, usually wall-mounted, that, when activated, initiates an alarm on a fire alarm system. In its simplest form, the user activates the alarm by pulling the handle down, which completes a circuit and locks the handle in the activated position, sending an alarm to the fire alarm control panel. After operation, most fire alarm pull stations must be restored to the ready position using a special tool or key in order for the panel to be reset. Primitive manual stations, requiring only a single action or hand motion to activate, can be subject to unwanted activation by jarring or accidental contact. Early strategies to cope with this problem included requiring the operator to break a pane of glass to release an internal spring-operated mechanism. Manual pull stations that require two hand motions, such as lift up and pull down, or push in and pull down, have since replaced the break-glass and single-action models in many modern installations

Simplex single action "T-bar" pull station

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

Heat Detector:

                         A heat detector is a fire alarm device designed to respond when the convected thermal energy of a fire increases the temperature of a heat sensitive element. The thermal mass and conductivity of the element regulate the rate flow of heat into the element. All heat detectors have this thermal lag. Heat detectors have two main classifications of operation, "rate-of-rise" and "fixed temperature". The heat detector is used to help in the reduction of damaged property. It is triggered when temperature increases

Apollo Series 65 CS High Temperature Heat Detector

Heat detectors are of Two types;

1.      Fixed temperature heat detectors:

                                                    This is the most common type of heat detector. Fixed temperature detectors operate when the heat sensitive eutectic alloy reaches the eutectic point changing state from a solid to a liquid. Thermal lag delays the accumulation of heat at the sensitive element so that a fixed-temperature device will reach its operating temperature sometime after the surrounding air temperature exceeds that temperature. The most common fixed temperature point for electrically connected heat detectors is 58°C (136.4°F). Technological developments[clarification needed] have enabled the perfection of detectors that activate at a temperature of 47°C (117°F), increasing the available reaction time and margin of safety.

2.      Rate-of-rise heat detectors:

                                            Rate-of-Rise (ROR) heat detectors operate on a rapid rise in element temperature of 6.7° to 8.3°C (12° to 15°F) increase per minute, irrespective of the starting temperature. This type of heat detector can operate at a lower temperature fire condition than would be possible if the threshold were fixed. It has two heat-sensitive thermocouples or thermistors. One thermocouple monitors heat transferred by convection or radiation while the other responds to ambient temperature. The detector responds when the first sensing element's temperature increases relative to the other.

Rate of rise detectors may not respond to low energy release rates of slowly developing fires. To detect slowly developing fires combination detectors add a fixed temperature element that will ultimately respond when the fixed temperature element reaches the design threshold.

Smoke Detector:

                           A smoke detector is a device that senses smoke, typically as an indicator of fire. Commercial security devices issue a signal to a fire alarm control panel as part of a fire alarm system, while household smoke detectors, also known as smoke alarms, generally issue a local audible or visual alarm from the detector itself.

                                               Smoke detectors are housed in plastic enclosures, typically shaped like a disk about 150 millimetres (6 in) in diameter and 25 millimetres (1 in) thick, but shape and size vary. Smoke can be detected either optically (photoelectric) or by physical process (ionization); detectors may use either, or both, methods. Sensitive alarms can be used to detect, and thus deter, smoking in areas where it is banned. Smoke detectors in large commercial, industrial, and residential buildings are usually powered by a central fire alarm system, which is powered by the building power with a battery backup. Domestic smoke detectors range from individual battery-powered units, to several interlinked mains-powered units with battery backup; with these interlinked units, if any unit detects smoke, all trigger even if household power has gone out.

Smoke Detector COFEM with approved EN 54-7

Types of  Smoke Detector:

1.      Photoelectric:

                     . A photoelectric, or optical smoke detector contains a source of infrared, visible, or ultraviolet light (typically an incandescent light bulb or light-emitting diode), a lens, and a photoelectric receiver (typically a photodiode). In spot-type detectors all of these components are arranged inside a chamber where air, which may contain smoke from a nearby fire, flows. In large open areas such as atria and auditoriums, optical beam or projected-beam smoke detectors are used instead of a chamber within the unit: a wall-mounted unit emits a beam of infrared or ultraviolet light which is either received and processed by a separate device, or reflected back to the receiver by a reflector. In some types, particularly optical beam types, the light emitted by the light source passes through the air being tested and reaches the photosensor. The received light intensity will be reduced due to scattering from particulates of smoke, air-borne dust, or other substances; the circuitry detects the light intensity and generates the alarm if it is below a specified threshold, potentially due to smoke. In other types, typically chamber types, the light is not directed at the sensor, which is not illuminated in the absence of particles. If the air in the chamber contains particles (smoke or dust), the light is scattered and some of it reaches the sensor, triggering the alarm.

Optical smoke detector
1: Optical chamber
2: Cover
3: Case moulding 
4: Photodiode (transducer)
5: Infrared LED

2.       Ionisation:

                 An ionization smoke detector uses a radioisotope, typically americium-241, to ionize air; a difference due to smoke is detected and an alarm is generated. Ionization detectors are more sensitive to the flaming stage of fires than optical detectors, while optical detectors are more sensitive to fires in the early smouldering stage

Flame Detector:

                          A flame detector is a sensor designed to detect and respond to the presence of a flame or fire, allowing flame detection. Responses to a detected flame depend on the installation, but can include sounding an alarm, deactivating a fuel line (such as a propane or a natural gas line), and activating a fire suppression system. When used in applications such as industrial furnaces, their role is to provide confirmation that the furnace is working properly; in these cases they take no direct action beyond notifying the operator or control system. A flame detector can often respond faster and more accurately than a smoke or heat detector due to the mechanisms it uses to detect the flame.

Types of Flame detector:

1.      Ultraviolet detector:

                             Ultraviolet (UV) detectors work by detecting the UV radiation emitted at the instant of ignition. While capable of detecting fires and explosions within 3–4 milliseconds, a time delay of 2–3 seconds is often included to minimize false alarms which can be triggered by other UV sources such as lightning, arc welding, radiation, and sunlight. UV detectors typically operate with wavelengths shorter than 300 nm to minimize the effects of natural background radiation. The solar blind UV wavelength band is also easily blinded by oily contaminant

2.      Infrared detector:

                         Infrared (IR) or wideband infrared (1.1 µm and higher) flame detectors monitor the infrared spectral band for specific patterns given off by hot gases. These are sensed using a specialized fire-fighting thermal imaging camera (TIC), a type of thermographic camera. False alarms can be caused by other hot surfaces and background thermal radiation in the area. Water on the detector's lens will greatly reduce the accuracy of the detector, as will exposure to direct sunlight. A special frequency range is 4.3 to 4.4 µm. This is a resonance frequency of CO2. During burning of a hydrocarbon (for example, wood or fossil fuels such as oil and natural gas) much heat and CO2 is released. The hot CO2 emits much energy at its resonance frequency of 4.3 µm. This causes a peak in the total radiation emission and can be well detected.

OUTPUT DEVICES

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

Visual Output Devices

                        A visual signal lets users know the status of the alarm system if activated. Visual

 devices may be mounted inside or outside May consist of...

 Strobe lights

 LED’s

 On / Off site printer

Selection of Detectors for different Area

S.No	Plant Area	Types 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	Ionization type Smoke Detector
4	Office rooms / storage rooms	Ionisation type smoke detector
5	Battery rooms and chemically corrosive areas.	Corrosion resistant, Rate of rise of temperature heat detector with fixed temperature setting.
6	Station building / Plant area	Infrared flame detectors (where oil tanks are located), spray tanks rate of rise of temp. detector with fixed element
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	Junction towers	Flame proof heat detectors, flame proof manual call points
9	Conveyor tunnels	Flame proof infrared detectors, flame proof MCPs, LHS Cables
10	Hazardous plant areas such as fuel oil / lube oil, DG houses, H2 generating plants and hydrogen storage areas.	Flame proof rate of rise of temperature detector with fixed element and flame proof MCP

FIRE SPRINKLERS

Fire sprinklers utilize water by direct application onto flames and heat, which causes cooling of the combustion process and prevents ignition of adjacent combustibles. They are most effective during the fire's initial flame growth stage, while the fire is relatively easy to control. A properly selected sprinkler will detect the fire's heat, initiate alarm, and begin suppression within moments after flames appear. In most instances sprinklers will control fire advancement within a few minutes of their activation, which will in turn result in significantly less damage than otherwise would happen without sprinklers.

 Among the potential benefits of sprinklers are the following:

1.      Immediate identification and control of a developing fire. Sprinkler systems respond at all times, including periods of low occupancy. Control is generally instantaneous.

2.      Immediate alert. In conjunction with the building fire alarm system, automatic sprinkler systems will notify occupants and emergency response personnel of the developing fire.

3.      Reduced heat and smoke damage. Significantly less heat and smoke will be generated when the fire is extinguished at an early stage.

4.      Enhanced life safety. Staff, visitors and fire fighters will be subject to less danger when fire growth is checked.

5.      Design flexibility. Egress route and fire/smoke barrier placement becomes less restrictive since early fire control minimizes demand on these systems. Many fire and building codes will permit design and operations flexibility based on the presence of a fire sprinkler system.

6.      Enhanced security. A sprinkler controlled fire can reduce demand on security forces by minimizing intrusion and theft opportunities.

7.      Decreased insurance expenditure. Sprinkler controlled fires are less damaging than fires in nonsprinklered buildings. Insurance underwriters may offer reduced premiums in sprinkler protected properties.

Table 31: Fire Suppression Water Application Rates
Delivery Method	Liters/min.	Gallons/min.
Portable Fire Extinguisher/Appliance	10	2.5
Occupant Use Fire Hose	380	100
Sprinkler (1)	95	25
Sprinkler (2)	180	47
Sprinkler (3)	260	72
Fire Department, Single 1.5 Hose	380	100
Fire Department, Double 1.5 Hose	760	200
Fire Department, Single 2.5 Hose	950	250
Fire Department, Double 2.5 Hose	1900	500

Sprinkler water is transported to fire via a system of fixed pipes and fittings. Piping material options include various steel alloys, copper, and fire resistant plastics. Steel is the traditional material with copper and plastics utilized in many sensitive applications. Primary considerations for selection of pipe materials include:

1.      Ease of installation. The easier the material is installed, the less disruption is imposed on the institution's operations and mission. The ability to install a system with the least amount of disturbance is an important consideration, especially in sprinkler retrofit applications where building use will continue during construction.

2.      Cost of material versus cost of protected area. Piping typically represents the greatest single cost item in a sprinkler system. Often there is a temptation to reduce costs by utilizing less expensive piping materials that may be perfectly acceptable in certain instances, i.e. office or commercial environs. However, in heritage applications where the value of contents may be far beyond sprinkler costs, appropriateness of the piping rather than cost should be the deciding factor.

3.      Contractor familiarity with materials. A mistake to be avoided is one in which the contractor and pipe materials have been selected, only to find out that the contractor is inexperienced with the pipe. Prefabrication requirements or other installation constraints. In some instances, such as in fine art vaults, requirements may be imposed to limit the amount of work time in the space. This will often require extensive prefabrication work outside of the work area. Some materials are easily adapted to prefabrication.

4.      Material cleanliness. Some pipe materials are cleaner to install than others. This will reduce the potential for soiling collections, displays, or building finishes during installation. Various materials are also resistant to accumulation in the system water, which could discharge onto collections. Cleanliness of installation and discharge should be a consideration.

5.      Labor requirements. Some pipe materials are heavier or more cumbersome to work with than others. Consequently additional workers are needed to install pipes, which can add to installation costs. If the number of construction workers allowed into the building is a factor, lighter materials may be beneficial.

TYPES OF FIRE DETECTION SYSTEM

1.      Conventional FDA System

2.      μ-P Based Addressable FDA System

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.

 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 and not by

individual switches for different zones / detectors.

Addressable Fire Detection & Alarm

System

It is an automatic fire detection & alarm system consists of fire

detectors & 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

1.       Addressable I/P devices

2.       Addressable O/P devices

3.       Control panel

4.       Constant power supply

5.       Emergency Battery supply

Microprocessor Based  control  Panel:

1.       Processor(CPU)

2.       Adequate number of loop modules for detector loops

3.       A coloured VDU monitor with keyboard

4.       Output modules for alarm

5.       Output control & interlocks

6.       Communication  mdules for  interfacing

BENEFITS OF μ-P BASED ADDRESSABLE FDA SYSTEM

1.       Continuous supervision of the detector connecting lines, individual

2.      detector performance / operation and disconnection / removal of

3.      detectors.

4.       Discrimination between a real fire and false fire conditions by

5.      incorporating signal verification and other features.

6.       Individual detector addressing capability.

7.       Detection of over / under sensitive detectors and automatic calibration by

8.      increasing or decreasing their sensitivity levels based on environmental

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

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

11.   Facility shall be provided for alteration programme according to needs.

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-UL26830

Public addressing System (PA System)

A public address system : (PAsystem) is an electronic sound amplification and distribution system with a microphone, amplifier and loudspeakers, used to allow a person to address a large public. The term is also used for systems which may additionally have a mixing console, and amplifiers and loudspeakers suitable for music as well as speech, used to reinforce a sound source, such as recorded music or a person giving a speech or distributing the sound throughout a venue or building.

What is a PA system?

A “Public Address” system is anything that amplifies sound so more people can hear it. The most basic example might be a megaphone, or single microphone and speaker, used to make someone’s voice louder. Public address systems consist of input sources, amplifiers, control and monitoring equipment, and loudspeakers. The primary input sources are microphones for live announcements and a source of recorded sound.

There may be a system which allows operators, or automated equipment, to select from a number of standard prerecorded messages. These input sources are fed into preamplifiers and signal routers that determine the zones to which the audio signal is fed.The preamplified signals are then passed into the amplifiers. Depending on local practices these amplifiers will usually amplify the audio signals to 50V, 70V or 100V speaker line level. Control equipment monitors the amplifiers and speaker lines for faults before it reaches the loudspeakers. This control equipment is also used for separating zones in a PA system. The loudspeaker is used to convert electrical signals into sound.

A Microphone : (colloquially called a mic or mike; both pronounced /ˈmaɪk/) is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal. Microphones are used in many applications such as telephones, tape recorders, hearing aids, motion picture production, live and recorded audio engineering, FRS radios, megaphones, in radio and television broadcasting and in computers for recording voice, speech recognition, VoIP, and for non-acoustic purposes such as ultrasonic checking or knock sensors.

Mixer: There have been two conventional categories of live sound mixers for quite a while: powered and unpowered analog mixers. Now there is also a new generation of digital consoles designed for studio and live sound applications that bring the added benefits of total recall mixing and onboard effects.

An Amplifier: is a device for increasing the power of a signal by use of an external energy source.In an electronic amplifier, the input "signal" is usually a voltage or a current. Other types exist; a fluidic amplifier increases the power of signals represented as flow of gas or liquid, for example. Amplifiers may be classified in a variety of ways depending on their application, the frequency range they cover, or the active devices used. Ideally an amplifier increases the power of a signal without otherwise altering it; practical amplifiers have finite distortion and noise which they invariably add to the signal.

A Loudspeaker (or "speaker") is an Electroacoustic transducer that produces sound in response to an electrical audio signal input. Non-electrical loudspeakers were developed as accessories to telephone systems, but electronic amplification by vacuum tube made loudspeakers more generally useful. The most common form of loudspeaker uses a paper cone supporting a voice coil electromagnet acting on a permanent magnet, but many other types exist. Where accurate reproduction of sound is required, multiple loudspeakers may be used, each reproducing a part of the audible frequency range. Miniature loudspeakers are found in devices such as radio and TV receivers, and many forms of music players. Larger loudspeaker systems are used for music, sound reinforcement in theatres and concerts, and in public address systems.