Fire Detection and Alarm System Basics

Fire Detection and Alarm System Basics
Hochiki America Corporation 7051 Village Drive, Suite 100 Buena Park, California 90621

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

Fire Detection Principles
Manual Fire Detection - Pull Stations Manual fire detection is the oldest method of detection. In the simplest form, a person yelling can provide fire warning. In buildings, however, a person's voice may not always transmit throughout the structure. For this reason, manual alarm stations are installed. The general design philosophy is to place stations within reach along paths of escape. It is for this reason that they can usually be found near exit doors in corridors and large rooms. The advantage of manual alarm stations is that, upon discovering the fire, they provide occupants with a readily identifiable means to activate the building fire alarm system. The alarm system can then serve in lieu of the shouting person's voice. They are simple devices, and can be highly reliable when the building is occupied. The key disadvantage of manual stations is that they will not work when the building is unoccupied. They may also be used for malicious alarm activations. Nonetheless, they are an important component in any fire alarm system. 2007 NFPA 72, Manual Fire Alarm Box. A manually operated device used to initiate an alarm signal.

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

Automatic Detectors – Photoelectric Hochiki SLR-24V detector 2007 NFPA 72, Light Scattering Smoke Detection. The principle of 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 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 alarm condition when it meets preset criteria.

Automatic Detectors – Photoelectric In the normal case, the light from the light source on the left shoots straight across and misses the sensor. When smoke enters the chamber, however, the smoke particles scatter the light and some amount of light hits the sensor. A – Light Source B – Photo Sensor

Automatic Detectors – Ionization Ionization smoke detectors use an ionization chamber and a source of ionizing radiation 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. Inside the ionization detector is a small amount (perhaps 1/5000th of a gram) of Americium-241. The radioactive element americium has a half-life of 432 years, and is a good source of alpha particles. An ionization chamber is very simple. It consists of two plates with a voltage across them, along with a radioactive source of ionizing radiation. Hochiki SIJ-24 detector 2007 NFPA 72, Ionization Smoke Detection. The principle of using a small amount of 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 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.

Automatic Detectors – Ionization Ionization Smoke detectors 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 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 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 sense the small amount of electrical current that these electrons and ions moving toward the plates represent. 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 the plates and sets off the horn.

Automatic Detectors – Heat/Thermal 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 with proliferation of various types of devices. 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 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 ambient conditions would not allow the use of other fire detection devices, or when speed of detection is not a prime consideration. 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 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 physical or electrical property of a material or gas. 2007 NFPA 72, Heat Detector. A fire detector that detects either abnormally high temperature, or rate of temperature rise, or both. Heat detectors can be sub-divided by their operating principles:

Automatic Detectors – Fixed Temp. 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 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 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 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 immediate fire area operate. Hochiki DFE Series Heat Detector 2007 NFPA 72, Fixed-Temperature Detector. A device that responds when its operating element becomes heated to a predetermined level.

Automatic Detectors – Rate-of-Rise 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 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 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 ambient temperature that are expected under non-fire conditions. Hochiki DSC-EA Heat Detector 2007 NFPA 72, Rate-of-Rise Detector. A device that responds when the temperature rises at a rate exceeding a predetermined value

Automatic Detectors – Combination 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 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 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 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 eutectic metal. When the fixed-temperature element reaches its designated operating temperature, the eutectic metal fuses and releases the spring, which closes the contact. Hochiki Photoelectric/Heat Smoke Detector Hochiki DCD Series Fixed Temp/Rate of Rise Heat Detector 2007 NFPA 72, Combination Detector. 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 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 sensing method employed.

Automatic Detectors – Flame A flame detector responds either to radiant energy visible to the human eye (approx 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 capability of the detector. 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 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 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 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 from the manufacturer's design staff. 2007 NFPA 72, Flame Detector. A radiant energy-sensing detector that detects the radiant energy emitted by a flame. 2007 NFPA 72, Radiant Energy-Sensing Fire Detector. A device that detects radiant energy, such as ultraviolet, visible, or infrared, that is emitted as a product of combustion reaction and obeys the laws of optics.

Automatic Detectors – Flame 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 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 blocked by objects placed in front of them. The infrared-type detector, however, has some capability for detecting radiation reflected from walls. Hochiki HF-24 Flame Detector

Automatic Detectors – Linear Type 2007 NFPA 72, Line-Type Detector. A device in which detection is continuous along a path. Typical examples are rate-of-rise pneumatic tubing detectors, projected beam smoke detectors, and heat sensitive cable. 2007 NFPA 72, Projected Beam-Type Detector. A type of photoelectric light obscuration smoke detector wherein the beam spans the protected area. 2007 NFPA 72, Photoelectric Light Obscuration Detection. The principle 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 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 alarm condition when it meets preset criteria.

Automatic Detectors – Air Sampling 2007 NFPA 72, Air Sampling-Type Detector. A detector that 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 protected area back to the detector through air sampling ports, piping, or tubing. At the detector, the air is analyzed for fire products.

Building Notification
Notification Appliances 2007 NFPA 72, Notification Appliance. A fire alarm system component such as a bell, horn, speaker, light or text display that provides audible, tactile, or visible outputs, or any combination thereof. 2007 NFPA 72, Audible Notification Appliance. A notification appliance that alerts by the sense of hearing. 2007 NFPA 72, Visible Notification Appliance. A notification appliance that alerts by the sense of sight.

Fire Alarm Circuit Classes
2007 NFPA 72, Class. Initiating device circuits, notification appliance circuits, and signaling line circuits shall be permitted to be designated as either Class A or Class B, depending on their performance during nonsimultaneous single circuit fault conditions as specified by the following: (1) Initiating device circuits and signaling line circuits that transmit an alarm or supervisory signal, or notification appliance circuits that allow all connected devices to operate during a single open or a nonsimultaneous single ground fault on any circuit conductor, shall be designated as Class A (2) Initiating device circuits and signaling line circuits that do not transmit an alarm or supervisory signal, or notification appliance circuits that do not allow all connected devices to operate beyond the location of a single open on any circuit conductor, shall be designated as Class B 2007 NFPA 72, An open or ground fault condition shall result in the annunciation of a trouble signal at the protected premise within 200 seconds as required in 4.4.7

Class B Circuits Class B Initiating Device Circuit 4.7K EOLR Class B Notification Appliance Circuit 4.7K EOLR End of line supervision resistors are required to supervise the integrity of the loop.

Class B Circuits Class B Initiating Device Circuit 4.7K EOLR 4.7K EOLR Class B Notification Appliance Circuit Single open circuit condition causes a trouble on the panel and renders all devices beyond the fault inoperative.

Class A Circuits Class A Initiating Device Circuit Class A Notification Appliance Circuit End of line supervision resistors are not necessary as the loop returns to the panel and is driven from both ends.

Class A Circuits Class A Initiating Device Circuit Class A Notification Appliance Circuit Single open circuit condition causes a trouble on the panel. All devices on the loop remain operative.

Additional Fire Alarm Terminology
Addressable Device - A fire alarm system component with discreet identification that can have its status individually identified or that is used to individually control other functions. Analog Addressable Sensor - An initiating device that transmits a signal indicating varying degrees of condition as contrasted with a conventional or addressable initiating device, which can only indicate an off/on condition. Signaling Line Circuit (SLC) - 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 both are carried. SLC Interface - A system component that connects a signaling line circuit to any combination of initiating devices, initiating device circuits, notification appliances, notification appliance circuits, system control outputs and other signaling line circuits. Protocol - A language for communicating between control panels and their proprietary devices.

Comparing System Types
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: Conventional Addressable Analog Addressable Conventional Systems Conventional control panels range in size from 1 zone to over 100 zones. Zones typically consist of some or all of the initiating devices in an area or floor of a building. Some control panels zone capacity is expandable while others are not, limiting its usefulness if a facility adds additional buildings or rooms.

Conventional Systems FACP
Zone 1 4.7K EOLR Zone 2 FACP FIRE SILENT KNIGHT FIRE SILENT KNIGHT FIRE SILENT KNIGHT FIRE SILENT KNIGHT FIRE SILENT KNIGHT NAC 1 4.7K EOLR Multiple devices are combined into a single zone. Zones can contain 30 or more devices.

Conventional Systems Zone 1 4.7K EOLR Zone 2 FIRE SILENT KNIGHT NAC 1 4.7K EOLR Care must be taken when laying out zones to comply with code requirements.

Zone Considerations 2007 NFPA Limits the number of waterflow switches in a single zone to 5. 2007 NFPA Limits the number of supervisory devices in a single zone to 20. 2007 NFPA 72 Annex A Suggests that the maximum number of square feet in a single zone be limited to no more than 22,500.

Conventional Systems Zone #1 4.7K EOLR Zone #2 NAC #1 4.7K EOLR Wiring must be installed in a supervised manner either Class A, or Class B with an EOLR.

Conventional Systems FIRE!
Zone #1 4.7K EOLR Zone #2 FIRE! NAC #1 4.7K EOLR Alarm conditions are annunciated by zone only. Inspection is required to determine the device.

Conventional Systems Zone #1 4.7K EOLR Zone #2 NAC #1 4.7K EOLR 4.7K EOLR Trouble conditions are annunciated by zone only. Inspection is required to determine the cause.

Conventional Systems Zone #1 4.7K EOLR Zone #2 RJ RJ NAC #1 4.7K EOLR Information transmitted to the central station is by zone at best. Many panels send Alarm, Supv, Trbl only.

Addressable Systems An addressable systems point capacity is determined by the amount of SLC “Signaling Line Circuits” it contains. Each SLC circuit provides power, communication, & supervision for all of the devices connected to it. Each SLC can accommodate over 100 addressable devices, depending upon the manufacturer. FACP

Addressable Systems FACP
Addressable Input Module (Waterflow) Addressable Heat Detector Addressable Smoke Detector Addressable Pull Station Addressable Smoke Detector FACP FIRE SILENT KNIGHT Addressable Relay Module (Fan Shutdown) NAC #1 4.7K EOLR Each SLC loop can contain a variety of addressable devices. Non-addressable devices are connected via addressable module.

Addressable Input Module (Waterflow) Addressable Heat Detector Addressable Smoke Detector Addressable Pull Station Addressable Smoke Detector FACP 004 FIRE SILENT KNIGHT 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 NAC #1 4.7K EOLR Each point on the SLC loop is given a unique address when installed.

Addressable Input Module (Waterflow) Addressable Heat Detector Addressable Smoke Detector Addressable Pull Station Addressable Smoke Detector FACP 004 FIRE SILENT KNIGHT 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 NAC #1 4.7K EOLR Supervision is accomplished from the panel by polling the devices on the SLC loop.

Addressable Input Module (Waterflow) Addressable Heat Detector Addressable Smoke Detector Addressable Pull Station Addressable Smoke Detector FACP 004 FIRE SILENT KNIGHT 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 NAC #1 4.7K EOLR Supervision is accomplished from the panel by polling the devices on the SLC loop. < Replay

Addressable Systems FACP FIRE!
Addressable Input Module (Waterflow) Addressable Heat Detector Addressable Smoke Detector Addressable Pull Station Addressable Smoke Detector FACP 004 FIRE SILENT KNIGHT 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 FIRE! NAC #1 4.7K EOLR ALARM POINT 006 LOBBY SMOKE DETECTOR Alarm conditions are annunciated by point allowing responding personnel to quickly find the fire.

Addressable Input Module (Waterflow) Addressable Heat Detector Addressable Smoke Detector Addressable Pull Station Addressable Smoke Detector FACP 004 FIRE SILENT KNIGHT 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 NAC #1 4.7K EOLR TRBL POINT 006 DISCONNECTED LOBBY SMOKE DETECTOR Trouble conditions can be located more quickly by analyzing the affected points.

Addressable Input Module (Waterflow) Addressable Heat Detector Addressable Smoke Detector Addressable Pull Station Addressable Smoke Detector FACP 004 FIRE SILENT KNIGHT 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 RJ RJ NAC #1 4.7K EOLR More detailed information can be sent to the central station aiding in a quick resolution to the problem.

Addressable Input Module (Waterflow) Addressable Heat Detector Addressable Smoke Detector Addressable Pull Station Addressable Smoke Detector FACP 004 FIRE SILENT KNIGHT 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 NAC #1 4.7K EOLR Since supervision is accomplished through polling, t-tapped wiring is permitted. (Class B wiring)

Addressable Systems FACP FIRE!
Addressable Input Module (Waterflow) Addressable Heat Detector Addressable Smoke Detector Addressable Pull Station Addressable Smoke Detector FACP 004 FIRE SILENT KNIGHT 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 FIRE! NAC #1 4.7K EOLR Many systems support flexible input/output programming to link initiating devices to outputs.

Comparison Conventional Addressable Lower initial equipment costs.
Wide range of compatible devices. Can be easier to program. Limited expansion capability. Addressable Easier to install. More system status information at the panel and central station. Input/Output programming much more flexible. Usually much more room available to expand.

Analog Addressable Systems
Detectors in an analog addressable systems become “sensors” relaying information to the control panel corresponding to how much smoke or heat that detector is sensing. The control panel makes the decisions based on this information when to alarm etc.

Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 10K EOLR NAC #1 Supervision is still checked by polling. In addition an analog value is transmitted to the panel for processing. HEAT DETECTOR MECHANICAL ROOM POINT A=062 NORMAL F=190

Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Detector 004 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 10K EOLR NAC #1 Supervision is still checked by polling. In addition an analog value is transmitted to the panel for processing. SMOKE DETECTOR LOBBY NORTH POINT A=060 NORMAL F=188

Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 10K EOLR NAC #1 Supervision is still checked by polling. In addition an analog value is transmitted to the panel for processing. RELAY MODULE FAN SHUTDOWN POINT A=N/A NORMAL F=N/A

Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 10K EOLR NAC #1 Supervision is still checked by polling. In addition an analog value is transmitted to the panel for processing. INPUT MODULE WATERFLOW POINT A=N/A NORMAL F=N/A

Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 10K EOLR NAC #1 Supervision is still checked by polling. In addition an analog value is transmitted to the panel for processing. INPUT MODULE MANUAL PULL POINT A=N/A NORMAL F=N/A

Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 10K EOLR NAC #1 Supervision is still checked by polling. In addition an analog value is transmitted to the panel for processing. SMOKE DETECTOR FRONT DESK POINT A=061 NORMAL F=189

Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 10K EOLR NAC #1 Supervision is still checked by polling. In addition an analog value is transmitted to the panel for processing. HEAT DETECTOR MECHANICAL ROOM POINT A=062 NORMAL F=190

Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 10K EOLR NAC #1 Supervision is still checked by polling. In addition an analog value is transmitted to the panel for processing. SMOKE DETECTOR LOBBY NORTH POINT A=060 NORMAL F=188

Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 10K EOLR NAC #1 Supervision is still checked by polling. In addition an analog value is transmitted to the panel for processing. RELAY MODULE FAN SHUTDOWN POINT A=N/A NORMAL F=N/A

Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 10K EOLR NAC #1 Supervision is still checked by polling. In addition an analog value is transmitted to the panel for processing. INPUT MODULE WATERFLOW POINT A=N/A NORMAL F=N/A

Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 10K EOLR NAC #1 Supervision is still checked by polling. In addition an analog value is transmitted to the panel for processing. INPUT MODULE MANUAL PULL POINT A=N/A NORMAL F=N/A

Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 10K EOLR NAC #1 SMOKE DETECTOR FRONT DESK POINT A=061 NORMAL F=189 < Replay

Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 10K EOLR NAC #1 HEAT DETECTOR MECHANICAL ROOM POINT A=062 NORMAL F=190 This analog value corresponds to the amount of heat or smoke in that detectors area of coverage. Higher = more.

Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 10K EOLR NAC #1 HEAT DETECTOR MECHANICAL ROOM POINT A=062 NORMAL F=190 If the analog value exceeds the alarm threshold, an alarm occurs. This alarm threshold is calculated by the panel.

Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 Addressable Relay Module (Fan Shutdown) 003 10K EOLR NAC #1 INPUT MODULE WATERFLOW POINT A=N/A NORMAL F=N/A Input/output modules do not relay analog values to the panel as they are monitoring or controlling on/off devices.

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

Drift Compensation Drift compensation is the process by which an analog addressable control panel automatically adjusts an analog detectors alarm threshold to compensate for contaminants such as dust. This ensures the detector maintains a consistent sensitivity level, helping to avoid false alarms due to dirty detectors.

Maintenance Alert Drift compensation occurs until it is nearing a point where it can no longer compensate and remain within U.L. requirements. This point is called “Maintenance Alert” Some systems handle a maintenance alert condition as a trouble while others flag the condition only, and continue to operate normally.

Calibration Trouble A detector in a maintenance alert condition will eventually go into calibration trouble if not serviced. A detector in calibration trouble is not functioning correctly and requires service immediately.

Adjustable (Day/Night) Sensitivity
In order to allow for varying environmental conditions or to provide quicker detection, analog systems typically allow you to change the sensitivity of a detector within a range of U.L. tolerances. This is typically made user friendly by giving the installer choices such as high-medium-low.

Adjustable (Day/Night) Sensitivity
By changing a detectors sensitivity you are instructing the panel to adjust its alarm threshold (analog) value up or down accordingly. Some systems allow this sensitivity adjustment to happen automatically on a day/night schedule.

U.L. Calibrated Sensitivity Test
1996 NFPA Detector sensitivity shall be tested within 1 year after installation and every alternate year thereafter. After the second required calibration test, where sensitivity tests indicate that the detector has remained within its listed and marked sensitivity range, the length of time shall be permitted to be extended to a maximum of 5 years. … Testing Methods A calibrated test method; or Manufacturers calibrated sensitivity test instrument; or Listed control equipment arranged for the purpose; or Smoke detector/control unit arrangement whereby the detector causes a signal at the control unit where its sensitivity is outside the acceptable range; or Other approved calibrated method acceptable to AHJ

U.L. Calibrated Sensitivity Test
Analog addressable control panels are UL listed for the purpose of performing the calibrated sensitivity testing internally. A printout from the panel is usually available to provide evidence to the AHJ that the test was performed.

How Analog Works 1% 2% 3% 4% .5% per foot obscuration 210 60 90 120 150 180 30 240 255 Detectors range of analog values Range (.5% - 4% per foot obscuration) that U.L. requires, to be listed as a smoke detector. In order to be listed with U.L. a smoke detector must alarm prior to reaching 4% per foot obscuration. It must also not alarm before it reaches .5% per foot obscuration.

How Analog Works 1% 2% 3% 4% .5% per foot obscuration 210 60 90 120 150 180 30 240 255 Detectors range of analog values On the other side of the graph, the range of analog values for the detector is plotted. In this case the range is

How Analog Works 1% 2% 3% 4% .5% per foot obscuration 210 60 90 120 150 180 30 240 255 Detectors range of analog values During power-up the detector performs a self test simulating 4% per foot obscuration. This value is plotted, in this case 193. 193

How Analog Works 1% 2% 3% 4% .5% per foot obscuration 210 60 90 120 150 180 30 240 255 Detectors range of analog values The system them initializes and records the 0% per foot obscuration (normal no smoke) value for that detector. In this case 60. 193

How Analog Works Calibration Curve
1% 2% 3% 4% .5% per foot obscuration 210 60 90 120 150 180 30 240 255 Detectors range of analog values A line is drawn connecting these two points. This line is referred to as the detectors calibration curve. 193 Calibration Curve

How Analog Works Once the calibration curve is established the panel can calculate an alarm threshold value for any valid sensitivity setting. Detectors range of analog values 255 240 210 193 180 150 145 120 112 90 60 30 .5% 1% 2% 3% 4% per foot obscuration

How Analog Works The panel also calculates the initial ranges for the drift compensation & maintenance alert functions. 1% 2% 3% 4% .5% per foot obscuration 210 60 90 120 150 180 30 240 255 Detectors range of analog values 193 Alarm 145 Calibration Trouble Maintenance Normal

How Analog Works As the detector gets dirty the clear air value will increase. Drift compensation adjusts the alarm threshold value accordingly. 1% 2% 3% 4% .5% per foot obscuration 210 60 90 120 150 180 30 240 255 Detectors range of analog values 193 Alarm Alarm 145 Calibration Trouble Calibration Trouble Maintenance Maintenance Normal Normal

How Analog Works As the detector gets dirty the clear air value will increase. Drift compensation adjusts the alarm threshold value accordingly. 1% 2% 3% 4% .5% per foot obscuration 210 60 90 120 150 180 30 240 255 Detectors range of analog values 193 Alarm Alarm Calibration Trouble Calibration Trouble Maintenance Maintenance Normal Normal

How Analog Works < Replay
Even though the detector has gotten dirty, it has still maintained a 2.5% sensitivity level. 1% 2% 3% 4% .5% per foot obscuration 210 60 90 120 150 180 30 240 255 Detectors range of analog values 193 Alarm Alarm 165 Calibration Trouble Calibration Trouble Maintenance Maintenance Normal Normal < Replay

Communication Protocols
Each manufacturer of (analog) addressable fire alarm systems utilize a unique communications protocol on the SLC loop to communicate between the control panel and the addressable devices. Most protocols are developed by detector manufacturers. Many manufacturers subtly modify standard protocols, developed by detector manufacturers, to provide a proprietary environment for their equipment & distributors.

Communication Protocols
Many of the panels installation requirements and operational parameters are based on the communication protocol used. SLC Loop Length SLC Loop Wire Type SLC Loop Communications Speed SLC Loop Alarm Response Time Communication protocols can be broken down into two categories. Non-Digital Digital

Comparing Protocols Addressable Input Module (Waterflow) Addressable Heat Detector Addressable Smoke Detector Addressable Pull Station Addressable Smoke Detector 004 001 002 006 005 003 Addressable Relay Module (Fan Shutdown) To take a closer look at communication protocols we can look at non-digital and digital SLC Loops through an oscilloscope.

Non-Digital Protocol Each detector when polled responds to the panel with square wave pulses.

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

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

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

Digital Protocol Using a digital protocol the panel looks for for a series of “1” or “on” bits that are detected by looking for voltage rather than the length of a pulse. 1 1 1 1 24v

Digital Protocol Even if a source of interference causes rounding off of the digital pulses the voltage is still present for the panel to determine the digital value. 1 1 1 1 24v

Digital Protocol Digital protocol panels do not typically require special cabling since interference does not pose any substantial signal problems. Retrofits can be done using existing cable. 1 1 1 1 24v

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

Non-Digital Loop Response
Addressable Input Module (Waterflow) Addressable Heat Detector Addressable Smoke Detector Addressable Pull Station Addressable Smoke Detector 004 FIRE SILENT KNIGHT 001 002 006 005 003 Addressable Relay Module (Fan Shutdown) ABC FIRE SYSTEMS ALL SYSTEMS NORMAL 15-Jan-00 3:10 PM

Addressable Input Module (Waterflow) Addressable Heat Detector Addressable Smoke Detector Addressable Pull Station Addressable Smoke Detector 004 FIRE SILENT KNIGHT 001 002 006 005 FIRE! 003 Addressable Relay Module (Fan Shutdown) ABC FIRE SYSTEMS ALL SYSTEMS NORMAL 15-Jan-00 3:10 PM A fire erupts at the Heat Detector (Point 001) while the system is polling the Smoke Detector (Point 002).

Addressable Input Module (Waterflow) Addressable Heat Detector Addressable Smoke Detector Addressable Pull Station Addressable Smoke Detector 004 FIRE SILENT KNIGHT 001 002 006 005 FIRE! 003 Addressable Relay Module (Fan Shutdown) ABC FIRE SYSTEMS ALL SYSTEMS NORMAL 15-Jan-00 3:10 PM An alarm is not initiated. The system continues polling until it reaches the point in alarm.

Addressable Input Module (Waterflow) Addressable Heat Detector Addressable Smoke Detector Addressable Pull Station Addressable Smoke Detector 004 FIRE SILENT KNIGHT 001 002 006 005 FIRE! 003 Addressable Relay Module (Fan Shutdown) ALARM POINT 001 HEAT DETECTOR 15-Jan-00 3:10 PM ALARM!

Addressable Input Module (Waterflow) Addressable Heat Detector Addressable Smoke Detector Addressable Pull Station Addressable Smoke Detector 004 FIRE SILENT KNIGHT 001 002 006 005 FIRE! 003 Addressable Relay Module (Fan Shutdown) ALARM POINT 001 HEAT DETECTOR 15-Jan-00 3:10 PM Systems with hundreds of points can take seconds or longer to respond to alarm conditions.

Digital Loop Response When an alarm occurs on most digital protocol systems, an interrupt request from the device sensing the alarm interrupts the polling sequence to immediately handle the alarm. Systems with hundreds of points will respond to alarms in the same amount of time that they would to smaller systems with very few points.

Digital Loop Response ABC FIRE SYSTEMS
Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 003 Addressable Relay Module (Fan Shutdown) ABC FIRE SYSTEMS ALL SYSTEMS NORMAL 15-Jan-00 3:10 PM

Digital Loop Response FIRE! ABC FIRE SYSTEMS
Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 FIRE! 003 Addressable Relay Module (Fan Shutdown) ABC FIRE SYSTEMS ALL SYSTEMS NORMAL 15-Jan-00 3:10 PM A fire erupts at the Heat sensor (Point 001) while the system is polling the Smoke Detector (Point 002).

Digital Loop Response FIRE! ABC FIRE SYSTEMS
Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 FIRE! 003 Addressable Relay Module (Fan Shutdown) ABC FIRE SYSTEMS ALL SYSTEMS NORMAL 15-Jan-00 3:10 PM The Heat Sensor (Point 001) interrupts the polling process to handle the alarm immediately.

ALARM! Digital Loop Response FIRE! ALARM POINT 001
Addressable Input Module (Waterflow) Addressable Heat Sensor Addressable Smoke Sensor Addressable Pull Station Addressable Smoke Sensor 004 001 002 006 005 FIRE! 003 Addressable Relay Module (Fan Shutdown) ALARM POINT 001 HEAT SENSOR 15-Jan-00 3:10 PM ALARM!

Hochiki America Corporation
THE END Hochiki America Corporation 7051 Village Drive, Suite 100 Buena Park, California 90621

Fire Detection and Alarm System Basics

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Fire Detection and Alarm System Basics

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