Honeywell Basic Fire Alarm Technology

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Fire Detection and Alarm

System Basics

Hochiki America Corporation

7051 Village Drive, Suite 100 Buena Park, California 90621

www.hochiki.com

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, 3.3.63.3 Manual Fire Alarm Box A manually operated device used

to initiate an alarm signal

Fire Detection Principles

Automatic Detectors – Spot type

2007 NFPA 72, 3.3.43.21 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

Fire Detection Principles

Automatic Detectors – Photoelectric

2007 NFPA 72, 3.3.181.4 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

Hochiki SLR-24V detector

Fire Detection Principles

Automatic Detectors – Photoelectric

A – Light Source

B – Photo Sensor

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

Fire Detection Principles

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

2007 NFPA 72, 3.3.181.2 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

Hochiki SIJ-24 detector

Fire Detection Principles

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

Fire Detection Principles

Automatic Detectors – Heat/Thermal

2007 NFPA 72, 3.3.43.9 Heat Detector A fire detector that detects either

abnormally high temperature, or rate of temperature rise, or both

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

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

Fire Detection Principles

Automatic Detectors – Fixed Temp.

2007 NFPA 72, 3.3.43.7 Fixed-Temperature Detector A device that responds

when its operating element becomes heated to a predetermined level

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

Fire Detection Principles

Automatic Detectors – Rate-of-Rise

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

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

Fire Detection Principles

Automatic Detectors – Combination

2007 NFPA 72, 3.3.43.4 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

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 DCD Series Fixed Temp/Rate of Rise Heat Detector

Hochiki

Photoelectric/Heat

Smoke Detector

Fire Detection Principles

Automatic Detectors – Flame

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

2007 NFPA 72, 3.3.43.16 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

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 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

Fire Detection Principles

Automatic Detectors – Flame

Due to their fast detection capabilities, flame detectors are generally used only in 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

high-Hochiki HF-24 Flame Detector

Fire Detection Principles

Automatic Detectors – Linear Type

2007 NFPA 72, 3.3.43.10 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, 3.3.43.15 Projected Beam-Type Detector A type of photoelectric light obscuration smoke detector wherein the beam spans the protected area

2007 NFPA 72, 3.3.181.3 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

Fire Detection Principles

Automatic Detectors – Air Sampling

2007 NFPA 72, 3.3.43.1 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, 3.3.113 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, 3.3.113.1 Audible Notification Appliance A notification appliance that alerts by the sense of hearing.

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

Fire Alarm Circuit Classes

2007 NFPA 72, 6.4.2.1 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, 6.4.2.2 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 Initiating Device Circuit

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Class B Notification Appliance Circuit

Class 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

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Class B Notification Appliance Circuit

Class B Circuits

Class A Initiating Device Circuit

Class A Notification Appliance Circuit

Class A Initiating Device Circuit

Class A Notification Appliance Circuit

Class A Circuits

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

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

Additional Fire Alarm Terminology

 Conventional control panels range in size from 1 zone

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 Systems Zone 1

4.7K EOLR

Zone 2

FIRE FIRE

SILENT KNIGHT

FIRE FIRE

SILENT KNIGHT

FIRE FIRE

SILENT KNIGHT

FIRE FIRE

SILENT KNIGHT

FIRE FIRE

SILENT KNIGHTFACP

NAC 1

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

4.7K EOLR

Conventional Systems

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

Zone 1

4.7K EOLR

Zone 2

FIRE FIRE

SILENT KNIGHT

NAC 1

4.7K EOLR

Zone Considerations

 2007 NFPA 72 6.8.5.5.2 Limits the number of waterflow switches in a single zone to 5.

 2007 NFPA 72 6.8.5.6.2 Limits the number of

supervisory devices in a single zone to 20.

 2007 NFPA 72 Annex A.4.4.6.6 Suggests that the

maximum number of square feet in a single zone be

limited to no more than 22,500.

4.7KEOLRZone #2

NAC #1

Conventional Systems

Alarm conditions are annunciated

by zone only Inspection is required to determine the device.

Zone #1

4.7KEOLR

4.7KEOLRZone #2

NAC #1

FIRE!

Conventional Systems

Trouble conditions are annunciated

by zone only Inspection is required

to determine the cause.

4.7K EOLR

Zone #1

4.7KEOLR

4.7KEOLRZone #2

NAC #1

4.7KEOLRZone #2

NAC #1

Addressable Systems

 An addressable systems point capacity is determined by the amount of SLC “Signaling Line Circuits” it contains.

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

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

FIRE FIRE

SILENT KNIGHT

Addressable Pull Station

Addressable Heat Detector

4.7K EOLR

NAC #1

Addressable Smoke Detector

Addressable Input Module (Waterflow)

Addressable Smoke Detector

Addressable Relay Module (Fan Shutdown)

Addressable Systems

Each point on the SLC loop is given

a unique address when installed

SILENT KNIGHT

Addressable Pull Station

Addressable Relay Module (Fan Shutdown)

Addressable Heat Detector

4.7K EOLR

NAC #1

Addressable Smoke Detector

Addressable Input Module (Waterflow)

Addressable Smoke Detector

Addressable Systems

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

SILENT KNIGHT

Addressable Pull Station

Addressable Relay Module (Fan Shutdown)

Addressable Heat Detector

4.7K EOLR

Addressable Smoke Detector

Addressable Input Module (Waterflow)

Addressable Smoke Detector

NAC #1

Addressable Systems

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

SILENT KNIGHT

Addressable Pull Station

Addressable Relay Module (Fan Shutdown)

Addressable Heat Detector

4.7K EOLR

Addressable Smoke Detector

Addressable Input Module (Waterflow)

Addressable Smoke Detector

NAC #1

Addressable Systems

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

SILENT KNIGHT

Addressable Pull Station

Addressable Relay Module (Fan Shutdown)

Addressable Heat Detector

4.7K EOLR

Addressable Smoke Detector

Addressable Input Module (Waterflow)

Addressable Smoke Detector

NAC #1

Addressable Systems

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

SILENT KNIGHT

Addressable Pull Station

Addressable Relay Module (Fan Shutdown)

Addressable Heat Detector

4.7K EOLR

Addressable Smoke Detector

Addressable Input Module (Waterflow)

Addressable Smoke Detector

NAC #1

Addressable Systems

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

SILENT KNIGHT

Addressable Pull Station

Addressable Relay Module (Fan Shutdown)

Addressable Heat Detector

4.7K EOLR

Addressable Smoke Detector

Addressable Input Module (Waterflow)

Addressable Smoke Detector

NAC #1

Addressable Systems

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

SILENT KNIGHT

Addressable Pull Station

Addressable Relay Module (Fan Shutdown)

Addressable Heat Detector

4.7K EOLR

Addressable Smoke Detector

Addressable Input Module (Waterflow)

Addressable Smoke Detector

NAC #1