Fire Detection and Alarm System Basics

Fire Detection and Alarm Fire Detection and Alarm System BasicsSystem Basics

Hochiki America CorporationHochiki America Corporation7051 Village Drive, Suite 1007051 Village Drive, Suite 100Buena Park, California 90621Buena Park, California 90621

www.hochiki.comwww.hochiki.com

Fire Detection and Alarm SystemsFire Detection and Alarm SystemsA key aspect of fire protection is to identify a developing fire emergency in a 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 timely manner, and to alert the building's occupants and fire emergency organizations.organizations.

This is the role of fire detection and alarm systems. Depending on the This is the role of fire detection and alarm systems. Depending on the anticipated fire scenario, building and use type, number and type of anticipated fire scenario, building and use type, number and type of occupants and criticality of contents and mission, these systems can provide occupants and criticality of contents and mission, these systems can provide several main functions:several main functions:

First, they provide a means to identify a developing fire through either First, they provide a means to identify a developing fire through either manual or automatic methods.manual or automatic methods.

Second, they alert building occupants to a fire condition and the need to Second, they alert building occupants to a fire condition and the need to evacuate.evacuate.

Another common function is the transmission of an alarm notification signal Another common function is the transmission of an alarm notification signal to the fire department or other emergency response organization.to the fire department or other emergency response organization.

They may also shut down electrical, air handling equipment or special They may also shut down electrical, air handling equipment or special process operations, and they may be used to initiate automatic suppression process operations, and they may be used to initiate automatic suppression systems.systems.

Fire Detection PrinciplesFire Detection PrinciplesManual Fire Detection - Pull StationsManual Fire Detection - Pull Stations

Manual fire detection is the oldest method of detection. In the Manual fire detection is the oldest method of detection. In the simplest form, a person yelling can provide fire warning. In simplest form, a person yelling can provide fire warning. In buildings, however, a person's voice may not always transmit buildings, however, a person's voice may not always transmit throughout the structure. For this reason, manual alarm stations throughout the structure. For this reason, manual alarm stations are installed. The general design philosophy is to place stations are installed. The general design philosophy is to place stations within reach along paths of escape. It is for this reason that they within reach along paths of escape. It is for this reason that they can usually be found near exit doors in corridors and large can usually be found near exit doors in corridors and large rooms. rooms.

The advantage of manual alarm stations is that, upon The advantage of manual alarm stations is that, upon discovering the fire, they provide occupants with a readily discovering the fire, they provide occupants with a readily identifiable means to activate the building fire alarm system. The identifiable means to activate the building fire alarm system. The alarm system can then serve in lieu of the shouting person's alarm system can then serve in lieu of the shouting person's voice. They are simple devices, and can be highly reliable when voice. They are simple devices, and can be highly reliable when the building is occupied. The key disadvantage of manual the building is occupied. The key disadvantage of manual stations is that they will not work when the building is stations is that they will not work when the building is unoccupied. They may also be used for malicious alarm unoccupied. They may also be used for malicious alarm activations. Nonetheless, they are an important component in activations. Nonetheless, they are an important component in any fire alarm system.any fire alarm system.

2007 NFPA 72, 3.3.63.3 2007 NFPA 72, 3.3.63.3 Manual Fire Alarm BoxManual Fire Alarm Box. A manually operated device used . A manually operated device used to initiate an alarm signal.to initiate an alarm signal.

Fire Detection PrinciplesFire Detection PrinciplesAutomatic Detectors – Spot typeAutomatic Detectors – Spot type

2007 NFPA 72, 3.3.43.21 2007 NFPA 72, 3.3.43.21 Spot Type DetectorSpot Type Detector. A device in which the detecting . A device in which the detecting Element is concentrated at a particular location. Typical examples are Element is concentrated at a particular location. Typical examples are Bimetallic detectors, fusible alloy detectors, certain pneumatic rate-of-riseBimetallic detectors, fusible alloy detectors, certain pneumatic rate-of-riseDetectors, certain smoke detectors, and thermoelectric detectors.Detectors, certain smoke detectors, and thermoelectric detectors.

Fire Detection PrinciplesFire Detection PrinciplesAutomatic Detectors – PhotoelectricAutomatic Detectors – Photoelectric

2007 NFPA 72, 3.3.181.4 2007 NFPA 72, 3.3.181.4 Light Scattering Smoke DetectionLight Scattering Smoke Detection. The principle of . The principle of using a light source and a photosensitive sensor arranged so that the rays from using a light source and a photosensitive sensor arranged so that the rays from the light source do not normally fall onto the photosensitive sensor. When smoke the light source do not normally fall onto the photosensitive sensor. When smoke particles inter the light path, some of the light is scattered by reflection and particles inter the light path, some of the light is scattered by reflection and refraction onto the sensor. The light signal is processed and used to convey an refraction onto the sensor. The light signal is processed and used to convey an alarm condition when it meets preset criteria.alarm condition when it meets preset criteria.

Hochiki SLR-24V detector

Fire Detection PrinciplesFire Detection PrinciplesAutomatic Detectors – PhotoelectricAutomatic Detectors – Photoelectric

A – Light SourceB – Photo Sensor

In the normal case, the light from the light source on the left shoots straight In the normal case, the light from the light source on the left shoots straight across and misses the sensor.across and misses the sensor.

When smoke enters the chamber, however, the smoke particles scatter When smoke enters the chamber, however, the smoke particles scatter the light and some amount of light hits the sensor.the light and some amount of light hits the sensor.

Fire Detection PrinciplesFire Detection PrinciplesAutomatic Detectors – IonizationAutomatic Detectors – Ionization

Ionization smoke detectors use an Ionization smoke detectors use an ionization chamberionization chamber and a source of and a source of ionizing radiationionizing radiation to detect smoke. This type of smoke detector is more common because it is inexpensive to detect smoke. This type of smoke detector is more common because it is inexpensive and better at detecting the smaller amounts of smoke produced by flaming fires.and better at detecting the smaller amounts of smoke produced by flaming fires.

Inside the ionization detector is a small amount (perhaps 1/5000th of a gram) of Inside the ionization detector is a small amount (perhaps 1/5000th of a gram) of Americium-Americium-241241. The radioactive element americium has a half-life of 432 years, and is a good source of . The radioactive element americium has a half-life of 432 years, and is a good source of alpha particlesalpha particles. .

An ionization chamber is very simple. It consists of two plates with a voltage across them, An ionization chamber is very simple. It consists of two plates with a voltage across them, along with a radioactive source of ionizing radiation.along with a radioactive source of ionizing radiation.

2007 NFPA 72, 3.3.181.2 2007 NFPA 72, 3.3.181.2 Ionization Smoke DetectionIonization Smoke Detection. The principle of using a small amount of . The principle of using a small amount of radioactive material to ionize the air between two differentially charged electrodes to sense the radioactive material to ionize the air between two differentially charged electrodes to sense the presence of smoke particles. Smoke Particles entering the ionization volume decrease the presence of smoke particles. Smoke Particles entering the ionization volume decrease the conductance of the air by reducing ion mobility. The reduced conductance signal is processed and conductance of the air by reducing ion mobility. The reduced conductance signal is processed and used to convey an alarm condition when it meets preset criteria.used to convey an alarm condition when it meets preset criteria.

Hochiki SIJ-24 detector

Fire Detection PrinciplesFire Detection PrinciplesAutomatic Detectors – IonizationAutomatic Detectors – IonizationIonization Smoke detectorsIonization Smoke detectors

The alpha particles generated by the americium have the following property: They ionize the The alpha particles generated by the americium have the following property: They ionize the oxygen and nitrogen atoms of the air in the chamber. To "ionize" means to "knock an electron off oxygen and nitrogen atoms of the air in the chamber. To "ionize" means to "knock an electron off of." When you knock an electron off of an atom, you end up with a free electron (with a negative of." When you knock an electron off of an atom, you end up with a free electron (with a negative charge) and an atom missing one electron (with a positive charge). The negative electron is charge) and an atom missing one electron (with a positive charge). The negative electron is attracted to the plate with a positive voltage, and the positive atom is attracted to the plate with a attracted to the plate with a positive voltage, and the positive atom is attracted to the plate with a negative voltage (opposites attract, just like with magnets). The electronics in the smoke detector negative voltage (opposites attract, just like with magnets). The electronics in the smoke detector sense the small amount of electrical current that these electrons and ions moving toward the sense the small amount of electrical current that these electrons and ions moving toward the plates represent. plates represent.

When smoke enters the ionization chamber, it disrupts this current -- the smoke particles When smoke enters the ionization chamber, it disrupts this current -- the smoke particles attach to the ions and neutralize them. The smoke detector senses the drop in current between attach to the ions and neutralize them. The smoke detector senses the drop in current between the plates and sets off the horn.the plates and sets off the horn.

Fire Detection PrinciplesFire Detection PrinciplesAutomatic Detectors – Heat/ThermalAutomatic Detectors – Heat/Thermal

2007 NFPA 72, 3.3.43.9 2007 NFPA 72, 3.3.43.9 Heat DetectorHeat Detector. A fire detector that detects either . A fire detector that detects either abnormally high temperature, or rate of temperature rise, or both.abnormally high temperature, or rate of temperature rise, or both.

Heat detectors are the oldest type of automatic fire detection device. They began Heat detectors are the oldest type of automatic fire detection device. They began development of automatic sprinklers in the 1860s and have continued to the present development of automatic sprinklers in the 1860s and have continued to the present with proliferation of various types of devices.with proliferation of various types of devices.

Heat detectors that only initiate an alarm and have no extinguishing function are still in use. Heat detectors that only initiate an alarm and have no extinguishing function are still in use. Although they have the lowest false alarm rate of all automatic fire detector devices, they Although they have the lowest false alarm rate of all automatic fire detector devices, they also are the slowest in fire detecting. A heat detector is best situated for fire detection in a also are the slowest in fire detecting. A heat detector is best situated for fire detection in a small confined space where rapidly building high-output fires are expected, in areas where small confined space where rapidly building high-output fires are expected, in areas where ambient conditions would not allow the use of other fire detection devices, or when speed ambient conditions would not allow the use of other fire detection devices, or when speed of detection is not a prime consideration.of detection is not a prime consideration.

Heat detectors are generally located on or near the ceiling and respond to the convected Heat detectors are generally located on or near the ceiling and respond to the convected thermal energy of a fire. They respond either when the detecting element reaches a thermal energy of a fire. They respond either when the detecting element reaches a predetermined fixed temperature or to a specified rate of temperature change. In general, predetermined fixed temperature or to a specified rate of temperature change. In general, heat detectors are designed to operate when heat causes a prescribed change in a heat detectors are designed to operate when heat causes a prescribed change in a physical or electrical property of a material or gas.physical or electrical property of a material or gas.

Heat detectors can be sub-divided by their operating principlesHeat detectors can be sub-divided by their operating principles ::

Fire Detection PrinciplesFire Detection PrinciplesAutomatic Detectors – Fixed Temp.Automatic Detectors – Fixed Temp.

2007 NFPA 72, 3.3.43.7 2007 NFPA 72, 3.3.43.7 Fixed-Temperature DetectorFixed-Temperature Detector. A device that responds . A device that responds when its operating element becomes heated to a predetermined level.when its operating element becomes heated to a predetermined level.

Fixed-temperature heat detectors are designed to alarm when the temperature of the Fixed-temperature heat detectors are designed to alarm when the temperature of the operating elements reaches a specific point. The air temperature at the time of alarm is operating elements reaches a specific point. The air temperature at the time of alarm is usually considerably higher than the rated temperature because it takes time for the air usually considerably higher than the rated temperature because it takes time for the air to raise the temperature of the operating element to its set point. This condition is called to raise the temperature of the operating element to its set point. This condition is called thermal lag. Fixed-temperature heat detectors are available to cover a wide range of thermal lag. Fixed-temperature heat detectors are available to cover a wide range of operating temperatures - from about 135'F (57'C) and higher. Higher temperatures operating temperatures - from about 135'F (57'C) and higher. Higher temperatures detectors are also necessary so that detection can be provided in areas normally detectors are also necessary so that detection can be provided in areas normally subject to high ambient temperatures, or in areas zoned so that only detectors in the subject to high ambient temperatures, or in areas zoned so that only detectors in the immediate fire area operate.immediate fire area operate.

Hochiki DFE Series Heat Detector

Fire Detection PrinciplesFire Detection PrinciplesAutomatic Detectors – Rate-of-RiseAutomatic Detectors – Rate-of-Rise

2007 NFPA 72, 3.3.43.18 2007 NFPA 72, 3.3.43.18 Rate-of-Rise DetectorRate-of-Rise Detector. A device that responds when the . A device that responds when the temperature rises at a rate exceeding a predetermined valuetemperature rises at a rate exceeding a predetermined value

One effect that flaming fire has on the surrounding area is to rapidly increase air One effect that flaming fire has on the surrounding area is to rapidly increase air temperature in the space above the fire. Fixed-temperature heat detectors will not temperature in the space above the fire. Fixed-temperature heat detectors will not initiate an alarm until the air temperature near the ceiling exceeds the design operating initiate an alarm until the air temperature near the ceiling exceeds the design operating point. The rate-of-rise detector, however, will function when the rate of temperature point. The rate-of-rise detector, however, will function when the rate of temperature increase exceeds a predetermined value, typically around 12 to 15'F (7 to 8'C) per increase exceeds a predetermined value, typically around 12 to 15'F (7 to 8'C) per minute. Rate-of-rise detectors are designed to compensate for the normal changes in minute. Rate-of-rise detectors are designed to compensate for the normal changes in ambient temperature that are expected under non-fire conditions.ambient temperature that are expected under non-fire conditions.

Hochiki DSC-EA Heat Detector

Fire Detection PrinciplesFire Detection PrinciplesAutomatic Detectors – CombinationAutomatic Detectors – Combination

2007 NFPA 72, 3.3.43.4 2007 NFPA 72, 3.3.43.4 Combination DetectorCombination Detector. A device that either responds to more than . A device that either responds to more than one of the fire phenomena or employs more than one operating principle to sense one of these one of the fire phenomena or employs more than one operating principle to sense one of these phenomena. Typical examples are a combination of a heat detector with a smoke detector or a phenomena. Typical examples are a combination of a heat detector with a smoke detector or a combination of rate-of-rise and fixed temperature heat detector. This device has listings for each combination of rate-of-rise and fixed temperature heat detector. This device has listings for each sensing method employed.sensing method employed.

Combination detectors contain more than one element which responds to fire. These detectors Combination detectors contain more than one element which responds to fire. These detectors may be designed to respond from either element, or from the combined partial or complete may be designed to respond from either element, or from the combined partial or complete response of both elements. An example of the former is a heat detector that operates on both response of both elements. An example of the former is a heat detector that operates on both the rate-of-raise and fixed-temperature principles. Its advantage is that the rate-of-rise element the rate-of-raise and fixed-temperature principles. Its advantage is that the rate-of-rise element will respond quickly to rapidly developing fire, while the fixed-temperature element will respond will respond quickly to rapidly developing fire, while the fixed-temperature element will respond to a slowly developing fire when the detecting element reaches its set point temperature. The to a slowly developing fire when the detecting element reaches its set point temperature. The most common combination detector uses a vented air chamber and a flexible diaphragm for the most common combination detector uses a vented air chamber and a flexible diaphragm for the rate-of-rise function, while the fixed-temperature element is usually leaf-spring restrained by a rate-of-rise function, while the fixed-temperature element is usually leaf-spring restrained by a eutectic metal. When the fixed-temperature element reaches its designated operating eutectic metal. When the fixed-temperature element reaches its designated operating temperature, the eutectic metal fuses and releases the spring, which closes the contact.temperature, the eutectic metal fuses and releases the spring, which closes the contact.

Hochiki DCD Series Fixed Temp/Rate of Rise Heat Detector

Hochiki Photoelectric/Heat Smoke Detector

Fire Detection PrinciplesFire Detection PrinciplesAutomatic Detectors – FlameAutomatic Detectors – Flame

2007 NFPA 72, 3.3.43.8 2007 NFPA 72, 3.3.43.8 Flame DetectorFlame Detector. A radiant energy-sensing detector that . A radiant energy-sensing detector that detects the radiant energy emitted by a flame.detects the radiant energy emitted by a flame.

2007 NFPA 72, 3.3.43.16 2007 NFPA 72, 3.3.43.16 Radiant Energy-Sensing Fire DetectorRadiant Energy-Sensing Fire Detector. A device that . A device that detects radiant energy, such as ultraviolet, visible, or infrared, that is emitted as a detects radiant energy, such as ultraviolet, visible, or infrared, that is emitted as a product of combustion reaction and obeys the laws of optics.product of combustion reaction and obeys the laws of optics.

A flame detector responds either to radiant energy visible to the human eye (approx. A flame detector responds either to radiant energy visible to the human eye (approx. 4000 to 7700 A) or outside the range of human vision. Similar to the human eye, flame 4000 to 7700 A) or outside the range of human vision. Similar to the human eye, flame detectors have a 'cone of vision', or viewing angle, that defines the effective detection detectors have a 'cone of vision', or viewing angle, that defines the effective detection capability of the detector.capability of the detector.

With this constraint, the sensitivity increases as the angle of incidence decreases. With this constraint, the sensitivity increases as the angle of incidence decreases. Such a detector is sensitive to glowing embers, coals, or flames which radiate energy Such a detector is sensitive to glowing embers, coals, or flames which radiate energy of sufficient intensity and spectral quality to actuate the alarm. Each type of fuel, when of sufficient intensity and spectral quality to actuate the alarm. Each type of fuel, when burning, produces a flame with specific radiation characteristics. A flame detection burning, produces a flame with specific radiation characteristics. A flame detection system must be chosen for the type of fire that is probable. For example an ultraviolet system must be chosen for the type of fire that is probable. For example an ultraviolet (UV) detector will respond to a hydrogen fire, but an infrared (IR) detector operating in (UV) detector will respond to a hydrogen fire, but an infrared (IR) detector operating in the 4.4 micron sensitivity range will not. It is imperative therefore; that a qualified fire the 4.4 micron sensitivity range will not. It is imperative therefore; that a qualified fire protection engineer is involved in the design of these systems, along with assistance protection engineer is involved in the design of these systems, along with assistance from the manufacturer's design staff.from the manufacturer's design staff.

Fire Detection PrinciplesFire Detection PrinciplesAutomatic Detectors – FlameAutomatic Detectors – Flame

Due to their fast detection capabilities, flame detectors are generally used only in high-Due to their fast detection capabilities, flame detectors are generally used only in high-hazard areas, such as fuel-loading platforms, industrial process areas, hyperbaric hazard areas, such as fuel-loading platforms, industrial process areas, hyperbaric chambers, high-ceiling areas, and atmospheres in which explosions or very rapid fires chambers, high-ceiling areas, and atmospheres in which explosions or very rapid fires may occur. Because flame detectors must be able to 'see' the fire, they must not be may occur. Because flame detectors must be able to 'see' the fire, they must not be blocked by objects placed in front of them. The infrared-type detector, however, has blocked by objects placed in front of them. The infrared-type detector, however, has some capability for detecting radiation reflected from walls.some capability for detecting radiation reflected from walls.

Hochiki HF-24 Flame Detector

Fire Detection PrinciplesFire Detection PrinciplesAutomatic Detectors – Linear TypeAutomatic Detectors – Linear Type

2007 NFPA 72, 3.3.43.10 2007 NFPA 72, 3.3.43.10 Line-Type DetectorLine-Type Detector. A device in which detection is . A device in which detection is continuous along a path. Typical examples are rate-of-rise pneumatic tubing detectors, continuous along a path. Typical examples are rate-of-rise pneumatic tubing detectors, projected beam smoke detectors, and heat sensitive cable.projected beam smoke detectors, and heat sensitive cable.

2007 NFPA 72, 3.3.43.15 2007 NFPA 72, 3.3.43.15 Projected Beam-Type DetectorProjected Beam-Type Detector. A type of photoelectric light . A type of photoelectric light obscuration smoke detector wherein the beam spans the protected area.obscuration smoke detector wherein the beam spans the protected area.

2007 NFPA 72, 3.3.181.3 2007 NFPA 72, 3.3.181.3 Photoelectric Light Obscuration DetectionPhotoelectric Light Obscuration Detection. The principle . The principle of using a light source and a photosensitive sensor onto which the principal portion of of using a light source and a photosensitive sensor onto which the principal portion of the source emission is focused. When smoke particles enter the light path, some of the the source emission is focused. When smoke particles enter the light path, some of the light is scattered and some of the light is absorbed, thereby reducing the light reaching light is scattered and some of the light is absorbed, thereby reducing the light reaching the receiving sensor. The light reduction signal is processed and used to convey an the receiving sensor. The light reduction signal is processed and used to convey an alarm condition when it meets preset criteria.alarm condition when it meets preset criteria.

Fire Detection PrinciplesFire Detection PrinciplesAutomatic Detectors – Air SamplingAutomatic Detectors – Air Sampling

2007 NFPA 72, 3.3.43.1 2007 NFPA 72, 3.3.43.1 Air Sampling-Type DetectorAir Sampling-Type Detector. A detector that . A detector that consists of a piping or tubing distribution network that runs from the detector to consists of a piping or tubing distribution network that runs from the detector to the area(s) to be protected. An aspiration fan in the detector draws air form the the area(s) to be protected. An aspiration fan in the detector draws air form the protected area back to the detector through air sampling ports, piping, or protected area back to the detector through air sampling ports, piping, or tubing. At the detector, the air is analyzed for fire products.tubing. At the detector, the air is analyzed for fire products.

Building NotificationBuilding NotificationNotification AppliancesNotification Appliances

2007 NFPA 72, 3.3.113 2007 NFPA 72, 3.3.113 Notification ApplianceNotification Appliance. A fire alarm system . A fire alarm system component such as a bell, horn, speaker, light or text display that provides component such as a bell, horn, speaker, light or text display that provides audible, tactile, or visible outputs, or any combination thereof.audible, tactile, or visible outputs, or any combination thereof.

2007 NFPA 72, 3.3.113.1 2007 NFPA 72, 3.3.113.1 Audible Notification ApplianceAudible Notification Appliance. A notification . A notification appliance that alerts by the sense of hearing.appliance that alerts by the sense of hearing.

2007 NFPA 72, 3.3.113.3 2007 NFPA 72, 3.3.113.3 Visible Notification ApplianceVisible Notification Appliance. A notification . A notification appliance that alerts by the sense of sight.appliance that alerts by the sense of sight.

Fire Alarm Circuit ClassesFire Alarm Circuit Classes2007 NFPA 72, 6.4.2.1 2007 NFPA 72, 6.4.2.1 ClassClass. Initiating device circuits, notification appliance . Initiating device circuits, notification appliance circuits, and signaling line circuits shall be permitted to be designated as either circuits, and signaling line circuits shall be permitted to be designated as either Class A or Class B, depending on their performance during nonsimultaneous Class A or Class B, depending on their performance during nonsimultaneous single circuit fault conditions as specified by the following:single circuit fault conditions as specified by the following:

(1) Initiating device circuits and signaling line circuits that transmit an alarm or (1) Initiating device circuits and signaling line circuits that transmit an alarm or supervisory signal, or notification appliance circuits that allow all connected supervisory signal, or notification appliance circuits that allow all connected devices to operate during a single open or a nonsimultaneous single ground devices to operate during a single open or a nonsimultaneous single ground fault on any circuit conductor, shall be designated as Class Afault on any circuit conductor, shall be designated as Class A

(2) Initiating device circuits and signaling line circuits that do not transmit an (2) Initiating device circuits and signaling line circuits that do not transmit an alarm or supervisory signal, alarm or supervisory signal, or notification appliance circuits that do not or notification appliance circuits that do not allow all connected devices to operateallow all connected devices to operate beyond the location of a single beyond the location of a single open on any circuit conductor, shall be designated as Class Bopen on any circuit conductor, shall be designated as Class B

2007 NFPA 72, 6.4.2.22007 NFPA 72, 6.4.2.2. An open or ground fault condition shall result in the . An open or ground fault condition shall result in the annunciation of a trouble signal at the protected premise within 200 seconds as annunciation of a trouble signal at the protected premise within 200 seconds as required in 4.4.7required in 4.4.7

Class B Initiating Device Circuit

4.7KEOLR

4.7KEOLR

Class B Notification Appliance Circuit

Class B CircuitsClass B Circuits

End of line supervision resistors are required to supervise the integrity of the loop.

Single open circuit condition causes a trouble on the panel and renders all devices beyond the fault inoperative.

Class B Initiating Device Circuit

4.7KEOLR

4.7KEOLR

Class B Notification Appliance Circuit

Class B CircuitsClass B Circuits

Class A Initiating Device Circuit

Class A Notification Appliance Circuit

Class A CircuitsClass A Circuits

End of line supervision resistors are not necessary as the loop returns to the panel and is driven from both ends.

Class A Initiating Device Circuit

Class A Notification Appliance Circuit

Class A CircuitsClass A Circuits

Single open circuit condition causes a trouble on the panel. All devices on the loop remain operative.

Addressable DeviceAddressable Device - A fire alarm system component with discreet identification that can - A fire alarm system component with discreet identification that can have its status individually identified or that is used to individually control other functions.have its status individually identified or that is used to individually control other functions.

Analog Addressable SensorAnalog Addressable Sensor - An initiating device that transmits a signal indicating varying - An initiating device that transmits a signal indicating varying degrees of condition as contrasted with a conventional or addressable initiating device, which degrees of condition as contrasted with a conventional or addressable initiating device, which can only indicate an off/on condition.can only indicate an off/on condition.

Signaling Line Circuit (SLC)Signaling Line Circuit (SLC) - A circuit or path between any combination of circuit interfaces, - A circuit or path between any combination of circuit interfaces, control units, or transmitters over which multiple system input signals or out put signals or control units, or transmitters over which multiple system input signals or out put signals or both are carried.both are carried.

SLC InterfaceSLC Interface - A system component that connects a signaling line circuit to any - A system component that connects a signaling line circuit to any combination of initiating devices, initiating device circuits, notification appliances, combination of initiating devices, initiating device circuits, notification appliances, notification appliance circuits, system control outputs and other signaling line notification appliance circuits, system control outputs and other signaling line circuits.circuits.

ProtocolProtocol - A language for communicating between control panels and their proprietary devices. - A language for communicating between control panels and their proprietary devices.

Additional Fire Alarm TerminologyAdditional Fire Alarm Terminology

Conventional control panels range in size from 1 zone Conventional control panels range in size from 1 zone to over 100 zones.to over 100 zones.

Zones typically consist of some or all of the initiating Zones typically consist of some or all of the initiating devices in an area or floor of a building.devices in an area or floor of a building.

Some control panels zone capacity is expandable Some control panels zone capacity is expandable while others are not, limiting its usefulness if a facility while others are not, limiting its usefulness if a facility adds additional buildings or rooms.adds additional buildings or rooms.

Comparing System TypesComparing System TypesTo better understand today’s newer technology, a firm understanding of the types of systems To better understand today’s newer technology, a firm understanding of the types of systems available is necessary. The three most popular types of systems installed today are:available is necessary. The three most popular types of systems installed today are:

•ConventionalConventional•AddressableAddressable•Analog AddressableAnalog Addressable

Conventional SystemsConventional Systems

Conventional SystemsConventional SystemsZone 1

4.7KEOLR

Zone 2FIREFIRE

SILENT KNIGHT

FIREFIRE

SILENT KNIGHT

FIREFIRE

SILENT KNIGHT

FIREFIRE

SILENT KNIGHT

FIREFIRE

SILENT KNIGHT

FACP

NAC 1

Multiple devices are combined into a single zone. Zones can contain 30 or more devices.

4.7KEOLR


Care must be taken when laying out zones to comply with code requirements.

Zone 1

4.7KEOLR

Zone 2FIREFIRE

SILENT KNIGHT

NAC 1

4.7KEOLR

Zone ConsiderationsZone Considerations

2007 NFPA 72 2007 NFPA 72 6.8.5.5.26.8.5.5.2 Limits the number of waterflow Limits the number of waterflow switchesswitches in a single zone to 5.in a single zone to 5.

2007 NFPA 72 2007 NFPA 72 6.8.5.6.26.8.5.6.2 Limits the number of Limits the number of supervisory devices in a single zone to 20.supervisory devices in a single zone to 20.

2007 NFPA 72 2007 NFPA 72 Annex A.4.4.6.6Annex A.4.4.6.6 Suggests that the Suggests that the maximum number of square feet in a single zone be maximum number of square feet in a single zone be limited to no more than 22,500.limited to no more than 22,500.


Wiring must be installed in a supervised manner either Class A, or Class B with an EOLR.

Zone #1

4.7KEOLR

4.7KEOLR

Zone #2

NAC #1


Alarm conditions are annunciated by zone only. Inspection is required to determine the device.

Zone #1

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4.7KEOLR

Zone #2

NAC #1

FIRE!


Trouble conditions are annunciated by zone only. Inspection is required to determine the cause.

4.7KEOLR

Zone #1

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4.7KEOLR

Zone #2

NAC #1


Information transmitted to the central station is by zone at best. Many panels send Alarm, Supv, Trbl only.

RJ RJ

Zone #1

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4.7KEOLR

Zone #2

NAC #1

Addressable SystemsAddressable Systems An addressable systems point capacity is An addressable systems point capacity is

determined by the amount of SLC “Signaling determined by the amount of SLC “Signaling Line Circuits” it contains.Line Circuits” it contains.

Each SLC circuit provides power, Each SLC circuit provides power, communication, & supervision for all of the communication, & supervision for all of the devices connected to it.devices connected to it.

Each SLC can accommodate over 100 Each SLC can accommodate over 100 addressable devices, depending upon the addressable devices, depending upon the manufacturer.manufacturer.

FACP

Addressable SystemsAddressable Systems

FACP

Each SLC loop can contain a variety of addressable devices. Non-addressable devices are connected via addressable module.

FIREFIRE

SILENT KNIGHT

AddressablePull Station

AddressableHeat Detector

4.7KEOLR

NAC #1

AddressableSmoke Detector

AddressableInput Module(Waterflow)


AddressableRelay Module

(Fan Shutdown)


Each point on the SLC loop is given a unique address when installed.

001 002

003

004

005006

FACP

FIREFIRE

SILENT KNIGHT



(Fan Shutdown)


4.7KEOLR

NAC #1





Supervision is accomplished from the panel by polling the devices on the SLC loop.

001 002

003

004

005006

FACP

FIREFIRE

SILENT KNIGHT



(Fan Shutdown)


4.7KEOLR




NAC #1


Supervision is accomplished from the panel by polling the devices on the SLC loop.

001 002

003

004

005006

FIREFIRE

SILENT KNIGHT



(Fan Shutdown)


4.7KEOLR




FACP

NAC #1


Supervision is accomplished from the panel by polling the devices on the SLC loop. < Replay< Replay

001 002

003

004

005006

FACP

FIREFIRE

SILENT KNIGHT



(Fan Shutdown)


4.7KEOLR




NAC #1


Alarm conditions are annunciated by point allowing responding personnel to quickly find the fire.

ALARM POINT 006

LOBBY SMOKE DETECTOR

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FACP

FIREFIRE

SILENT KNIGHT



(Fan Shutdown)


4.7KEOLR




NAC #1

FIRE!


Trouble conditions can be located more quickly by analyzing the affected points.

TRBL POINT 006DISCONNECTED LOBBY SMOKE DETECTOR

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FACP

FIREFIRE

SILENT KNIGHT



(Fan Shutdown)


4.7KEOLR




NAC #1


More detailed information can be sent to the central station aiding in a quick resolution to the problem.

RJRJ

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FACP

FIREFIRE

SILENT KNIGHT



(Fan Shutdown)


4.7KEOLR




NAC #1


Since supervision is accomplished through polling, t-tapped wiring is permitted. (Class B wiring)

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FACP

FIREFIRE

SILENT KNIGHT



(Fan Shutdown)


4.7KEOLR




NAC #1


Many systems support flexible input/output programming to link initiating devices to outputs.

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FACP

FIREFIRE

SILENT KNIGHT



(Fan Shutdown)


4.7KEOLR




NAC #1

FIRE!

ComparisonComparison ConventionalConventional

Lower initial Lower initial equipment costs.equipment costs.

Wide range of Wide range of compatible devices.compatible devices.

Can be easier to Can be easier to program.program.

Limited expansion Limited expansion capability.capability.

AddressableAddressable Easier to install.Easier to install. More system status More system status

information at the panel information at the panel and central station.and central station.

Input/Output Input/Output programming much more programming much more flexible.flexible.

Usually much more room Usually much more room available to expand.available to expand.

Analog Addressable SystemsAnalog Addressable Systems

Detectors in an analog addressable systems Detectors in an analog addressable systems become “sensors” relaying information to the become “sensors” relaying information to the control panel corresponding to how much control panel corresponding to how much smoke or heat that detector is sensing.smoke or heat that detector is sensing.

The control panel makes the decisions based The control panel makes the decisions based on this information when to alarm etc.on this information when to alarm etc.


AddressableRelay Module(Fan Shutdown)

AddressableHeat Sensor

10KEOLR

AddressableSmoke Sensor


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HEAT DETECTORMECHANICAL ROOMPOINT 001 A=062NORMAL F=190

Supervision is still checked by polling. In addition an analog value is transmitted to the panel for processing.

NAC #1


SMOKE DETECTORLOBBY NORTHPOINT 002 A=060NORMAL F=188






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10KEOLRNAC #1


RELAY MODULEFAN SHUTDOWNPOINT 003 A=N/ANORMAL F=N/A






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10KEOLRNAC #1


INPUT MODULE WATERFLOW POINT 004 A=N/ANORMAL F=N/A






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10KEOLRNAC #1



INPUT MODULE MANUAL PULL POINT 005 A=N/ANORMAL F=N/A





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10KEOLRNAC #1


SMOKE DETECTORFRONT DESKPOINT 006 A=061NORMAL F=189






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10KEOLRNAC #1








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10KEOLRNAC #1


SMOKE DETECTORLOBBY NORTHPOINT 002 A=060NORMAL F=188






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10KEOLRNAC #1


RELAY MODULEFAN SHUTDOWNPOINT 003 A=N/ANORMAL F=N/A






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10KEOLRNAC #1








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10KEOLRNAC #1



INPUT MODULE MANUAL PULL POINT 005 A=N/ANORMAL F=N/A





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10KEOLRNAC #1


SMOKE DETECTORFRONT DESKPOINT 006 A=061NORMAL F=189

< Replay< Replay





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10KEOLRNAC #1


This analog value corresponds to the amount of heat or smoke in that detectors area of coverage. Higher = more.






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10KEOLRNAC #1


If the analog value exceeds the alarm threshold, an alarm occurs. This alarm threshold is calculated by the panel.






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10KEOLRNAC #1



Input/output modules do not relay analog values to the panel as they are monitoring or controlling on/off devices.





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10KEOLRNAC #1

Analog Addressable Analog Addressable FeaturesFeatures

An analog addressable control panel is capable of An analog addressable control panel is capable of several enhanced features not available on conventional, several enhanced features not available on conventional, and some addressable systems.and some addressable systems. Drift Compensation / Maintenance AlertDrift Compensation / Maintenance Alert Adjustable Detector SensitivityAdjustable Detector Sensitivity Day/Night Detector Sensitivity AdjustmentDay/Night Detector Sensitivity Adjustment U.L. Calibrated Sensitivity Test InstrumentU.L. Calibrated Sensitivity Test Instrument

Drift CompensationDrift Compensation

Drift compensation is the process by which an analog Drift compensation is the process by which an analog addressable control panel automatically adjusts an addressable control panel automatically adjusts an analog detectors alarm threshold to compensate for analog detectors alarm threshold to compensate for contaminants such as dust. contaminants such as dust.

This ensures the detector maintains a consistent This ensures the detector maintains a consistent sensitivity level, helping to avoid false alarms due to sensitivity level, helping to avoid false alarms due to dirty detectors. dirty detectors.

Maintenance AlertMaintenance Alert

Drift compensation occurs until it is nearing a point Drift compensation occurs until it is nearing a point where it can no longer compensate and remain within where it can no longer compensate and remain within U.L. requirements. This point is called “Maintenance U.L. requirements. This point is called “Maintenance Alert” Alert”

Some systems handle a maintenance alert condition as Some systems handle a maintenance alert condition as a trouble while others flag the condition only, and a trouble while others flag the condition only, and continue to operate normally. continue to operate normally.

Calibration TroubleCalibration Trouble

A detector in a maintenance alert condition will A detector in a maintenance alert condition will eventually go into calibration trouble if not serviced.eventually go into calibration trouble if not serviced.

A detector in calibration trouble is not functioning A detector in calibration trouble is not functioning correctly and requires service immediately.correctly and requires service immediately.

Adjustable (Day/Night) Adjustable (Day/Night) SensitivitySensitivity

In order to allow for varying environmental conditions or In order to allow for varying environmental conditions or to provide quicker detection, analog systems typically to provide quicker detection, analog systems typically allow you to change the sensitivity of a detector within a allow you to change the sensitivity of a detector within a range of U.L. tolerances. range of U.L. tolerances.

This is typically made user friendly by giving the installer This is typically made user friendly by giving the installer choices such as high-medium-low. choices such as high-medium-low.

Adjustable (Day/Night) Adjustable (Day/Night) SensitivitySensitivity

By changing a detectors sensitivity you are instructing By changing a detectors sensitivity you are instructing the panel to adjust its alarm threshold (analog) value up the panel to adjust its alarm threshold (analog) value up or down accordingly.or down accordingly.

Some systems allow this sensitivity adjustment to Some systems allow this sensitivity adjustment to happen automatically on a day/night schedule.happen automatically on a day/night schedule.

U.L. Calibrated Sensitivity TestU.L. Calibrated Sensitivity Test

1996 NFPA 72 1996 NFPA 72 7-3.2.17-3.2.1Detector sensitivity shall be tested within 1 year after installation and Detector sensitivity shall be tested within 1 year after installation and every alternate year thereafter. After the second required calibration every alternate year thereafter. After the second required calibration test, where sensitivity tests indicate that the detector has remained test, where sensitivity tests indicate that the detector has remained within its listed and marked sensitivity range, the length of time shall be within its listed and marked sensitivity range, the length of time shall be permitted to be extended to a maximum of 5 years. …permitted to be extended to a maximum of 5 years. …

Testing MethodsTesting Methods A calibrated test method; orA calibrated test method; or Manufacturers calibrated sensitivity test instrument; orManufacturers calibrated sensitivity test instrument; or Listed control equipment arranged for the purpose; orListed control equipment arranged for the purpose; or Smoke detector/control unit arrangement whereby the Smoke detector/control unit arrangement whereby the

detector causes a signal at the control unit where its detector causes a signal at the control unit where its sensitivity is outside the acceptable range; orsensitivity is outside the acceptable range; or

Other approved calibrated method acceptable to AHJOther approved calibrated method acceptable to AHJ

Analog addressable control panels are UL listed for the Analog addressable control panels are UL listed for the purpose of performing the calibrated sensitivity testing purpose of performing the calibrated sensitivity testing internally.internally.

A printout from the panel is usually available to provide A printout from the panel is usually available to provide evidence to the AHJ that the test was performed.evidence to the AHJ that the test was performed.

U.L. Calibrated Sensitivity TestU.L. Calibrated Sensitivity Test

How Analog WorksHow Analog Works

1% 2% 3% 4%.5% per foot obscuration

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Detectors range of analog values

Range (.5% - 4% per foot obscuration) that U.L. requires, to be listed as a smoke detector.


On the other side of the graph, the range of analog values for the detector is plotted. In this case the range is 0-255.


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193

During power-up the detector performs a self test simulating 4% per foot obscuration. This value is plotted, in this case 193.


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193

The system them initializes and records the 0% per foot obscuration (normal no smoke) value for that detector. In this case 60.


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193

A line is drawn connecting these two points. This line is referred to as the detectors calibration curve.

Calibration Curve


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How Analog WorksHow Analog WorksOnce the calibration curve is established the panel can calculate an alarm threshold value for any valid sensitivity setting.

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193


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How Analog WorksHow Analog WorksThe panel also calculates the initial ranges for the drift compensation & maintenance alert functions.

Normal

Maintenance

Calibration Trouble

Alarm

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How Analog WorksHow Analog WorksAs the detector gets dirty the clear air value will increase.

Drift compensation adjusts the alarm threshold value accordingly.

Normal

Maintenance

Calibration Trouble

Alarm

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Maintenance

Calibration Trouble

Alarm

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Normal

Maintenance

Calibration Trouble

Alarm

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Maintenance

Calibration Trouble

Alarm

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Normal

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Calibration Trouble

Alarm

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Calibration Trouble

Alarm

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Normal

Maintenance

Calibration Trouble

Alarm

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Maintenance

Calibration Trouble

Alarm

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< Replay< Replay

Even though the detector has gotten dirty, it has still maintained a 2.5% sensitivity level.

Normal

Maintenance

Calibration Trouble

Alarm

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Maintenance

Calibration Trouble

Alarm

193


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Communication ProtocolsCommunication Protocols

Each manufacturer of (analog) addressable fire alarm systems Each manufacturer of (analog) addressable fire alarm systems utilize a unique communications protocol on the SLC loop to utilize a unique communications protocol on the SLC loop to communicate between the control panel and the addressable communicate between the control panel and the addressable devices.devices.

Most protocols are developed by detector manufacturers.Most protocols are developed by detector manufacturers.

Many manufacturers subtly modify standard protocols, developed by Many manufacturers subtly modify standard protocols, developed by detector manufacturers, to provide a proprietary environment for detector manufacturers, to provide a proprietary environment for their equipment & distributors. their equipment & distributors.

Communication ProtocolsCommunication Protocols Many of the panels installation requirements and operational Many of the panels installation requirements and operational

parameters are based on the communication protocol used.parameters are based on the communication protocol used. SLC Loop LengthSLC Loop Length SLC Loop Wire TypeSLC Loop Wire Type SLC Loop Communications SpeedSLC Loop Communications Speed SLC Loop Alarm Response TimeSLC Loop Alarm Response Time

Communication protocols can be broken down into two categories.Communication protocols can be broken down into two categories. Non-DigitalNon-Digital DigitalDigital

Comparing ProtocolsComparing Protocols

To take a closer look at communication protocols we can look at non-digital and digital SLC Loops through an oscilloscope.





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Non-Digital ProtocolNon-Digital Protocol

Each detector when Each detector when polled responds to the polled responds to the panel with square wave panel with square wave pulses.pulses.


The panel reads these The panel reads these square wave pulses and square wave pulses and determines the values by determines the values by measuring the length measuring the length (time) of each.(time) of each.


Various sources of Various sources of interference can cause interference can cause these square wave pulses these square wave pulses to round off. This makes to round off. This makes an accurate reading very an accurate reading very difficult.difficult.

?


Most manufacturers that Most manufacturers that utilize a non-digital utilize a non-digital protocol will specify protocol will specify special requirements such special requirements such as twisted or shielded as twisted or shielded wire to counteract this wire to counteract this problem.problem.

?

Digital ProtocolDigital Protocol

Using a digital protocol Using a digital protocol the panel looks for for a the panel looks for for a series of “1” or “on” bits series of “1” or “on” bits that are detected by that are detected by looking for voltage rather looking for voltage rather than the length of a pulse.than the length of a pulse.

0

1 1 1 1

0 0

24v24v


Even if a source of Even if a source of interference causes interference causes rounding off of the digital rounding off of the digital pulses the voltage is still pulses the voltage is still present for the panel to present for the panel to determine the digital determine the digital value.value.0

1 1 1 1

0 0

24v24v


Digital protocol panels do Digital protocol panels do not typically require not typically require special cabling since special cabling since interference does not interference does not pose any substantial pose any substantial signal problems. signal problems.

Retrofits can be done Retrofits can be done using existing cable.using existing cable.

0

1 1 1 1

0 0

24v24v

Non-digital Loop ResponseNon-digital Loop Response

When an alarm occurs on many non-digital protocol When an alarm occurs on many non-digital protocol systems, some panels must continue polling until it systems, some panels must continue polling until it reaches the alarming device, before an alarm is initiated.reaches the alarming device, before an alarm is initiated. Larger systems with hundreds of points can cause Larger systems with hundreds of points can cause

delays initiating an alarm.delays initiating an alarm.

Non-Digital Loop ResponseNon-Digital Loop Response

FIREFIRE

SILENT KNIGHT




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ABC FIRE SYSTEMS

ALL SYSTEMS NORMAL15-Jan-00 3:10 PM



ABC FIRE SYSTEMS


FIRE!

A fire erupts at the Heat Detector (Point 001) while the system is polling the Smoke Detector (Point 002).

FIREFIRE

SILENT KNIGHT




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ABC FIRE SYSTEMS


An alarm is not initiated. The system continues polling until it reaches the point in alarm.

FIREFIRE

SILENT KNIGHT




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FIRE!AddressableRelay Module(Fan Shutdown)


ALARMPOINT 001HEAT DETECTOR 15-Jan-00 3:10 PM

ALARM!

FIREFIRE

SILENT KNIGHT




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ALARMPOINT 001HEAT DETECTOR 15-Jan-00 3:10 PM

Systems with hundreds of points can take 15 -20 seconds or longer to respond to alarm conditions.

FIREFIRE

SILENT KNIGHT





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FIRE!

Digital Loop ResponseDigital Loop Response

When an alarm occurs on most digital protocol systems, When an alarm occurs on most digital protocol systems, an interrupt request from the device sensing the alarm an interrupt request from the device sensing the alarm interrupts the polling sequence to immediately handle interrupts the polling sequence to immediately handle the alarm.the alarm. Systems with hundreds of points will respond to Systems with hundreds of points will respond to

alarms in the same amount of time that they would to alarms in the same amount of time that they would to smaller systems with very few points.smaller systems with very few points.


ABC FIRE SYSTEMS




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ABC FIRE SYSTEMS


A fire erupts at the Heat sensor (Point 001) while the system is polling the Smoke Detector (Point 002).



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ABC FIRE SYSTEMS


The Heat Sensor (Point 001) interrupts the polling process to handle the alarm immediately.



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ALARM!ALARMPOINT 001HEAT SENSOR 15-Jan-00 3:10 PM



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THE ENDTHE END

Hochiki America CorporationHochiki America Corporation7051 Village Drive, Suite 1007051 Village Drive, Suite 100Buena Park, California 90621Buena Park, California 90621

www.hochiki.comwww.hochiki.com

Fire Detection and Alarm System Basics

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