Chapter 20 Fire Protection Systems Flashcards
Provide notification of an emergency condition to building occupants and in some cases the local emergency response organization.
Fire alarm systems
System component that receives input from automatic and manual fire alarm devices and may provide power to detection devices or communication devices.
Fire alarm control panel (FACP)
Either manually operated or automatic Automatic sense the products of combustion or other hazardous conditions. Send a signal to the FACP.
Initiating devices
List six examples of local notification devices.
Bells. Horns. Recorded voice message. Strobe Light. Speakers. Buzzers.
Name the four categories that notification devices fall under.
Audible. Visual. Textual. Tactile. (all can be used in combination)
What items may be located in the Fire Command Center (FCS)?
Fire alarm control panel. Smoke control station. Fire pump status indicators. Emergency elevator controls. Emergency communication systems. Spare sprinklers and fuses. Building plans and system diagrams.
Alarm system that alerts and notifies only occupants on the premises of the existence of a fire so that they can safely exit the building and call the fire dept. If a response by police or fire is needed, an occupant must notify the wanted agency.
Protected premises system (local alarm system).
Name the three types of local alarm systems.
Noncoded. Zoned/annunciated. Addressable
The simplest type of local alarm. If one alarm goes off they all go off. Only practical in small buildings.
Noncoded alarm.
A general location/ zone of what device was activated is given.
Zoned/annunciated alarm.
Displays the location of each initiating device. Can pinpoint the specific location of the initiating device.
Addressable alarm system
Continuously monitors a remote location for the purpose of reporting a supervisory, trouble, or alarm signal to the appropriate authorities. Predominant type of signal monitoring in the US.
Supervising Station Alarm Systems
List the four types of supervising station systems.
Auxiliary alarm system. Central station system. Proprietary system. Remote receiving systems.
System that is connected to a municipal fire alarm system. Alarms are transmitted to the public fire telecommunication center and appropriate agency is dispatched. Two types: Local energy System & Shunt System.
Auxiliary alarm system.
Auxiliary fire alarm system that has its own power source. Served by the municipal fire alarm box system.
Local Energy System
Auxiliary fire alarm system that is directly connected to the municipal alarm system. Alarms are automatically initiated over the municipal system.
Shunt System
Used to protect large buildings or multiple buildings. Alarms go to a common receiving building that is staffed with personnel who can take appropriate action when a alarm is sounded. Owned and operated by the property owners.
Proprietary System
Monitored by a contract service. (Alarm company)
Central Station System
System in which alarm signals from the protected premises are transmitted over a leased telephone line or by radio signal to a remote receiving station with a 24-hour staff; usually the fire depts alarm communication center.
Remote Receiving System
Identify the presence of fire or products of combustion and send a signal to the alarm system. Can be manual or automatic.
Alarm initiating device
A manual pull station is required to have what incorporated in its design?
It must be red with white lettering that species what the device is and how to use it.
Alarm initiating device that is designed to be responsive to a predetermined rate of temp or to predetermined temp level.
Heat Detectors
Name the two types of heat detectors.
Fixed temp. Rate of rise
What detectors have the least false activation’s and are also the slowest to activate?
Fixed temp heat detectors.
What is the common set temp for a fixed temp detector in living spaces? For attics or other areas subject to elevated temps?
165 F. 200 F.
Name three types of fixed temp heat detectors mechanisms.
Expansion of heated material. Melting of heated material. Changes in resistance of heated material.
A fragile bulb contains liquid and a air bubble. When the liquid is heat what happens?
The air bubble is absorbed and the glass breaks.
What type of initiating device mechanism may still be in use but is no longer made.
Frangible bulb
Can detect heat over a linear area parallel to the detector.
Continuous line detector.
A continuous line detector that continuous of a inner core and sheath that are separated by a electrically insulating semiconductor. When the temp increase the electrical flow increase causing a alarm initiation. This device will…… when the temp decreases.
reset (tubing type continuous line detector)
A type of continuous line detector that has two wires each with insulation. When the insulation melts the circuit is complete causing a what? Must be replaced to be reset.
Alarm initiation. (Wire-type continuous line detector)
Heat detector that uses two metals bonded together each having a different thermal expansion temp. When one is heated it bends either making or breaking a circuit. Most will reset when cooled but need to be inspected.
Bimetallic detector.
Temperature sensitive device that sounds an alarm when the temp changes at a preset value, such as 12 f to 15 f in one minute. Automatically reset if undamaged.
Rate of rise heat detector.
A rate of rise heat detector is reliable except when.
Installed next to a door in a AC building on a hot day.
Name four types of rate of rise heat detectors.
Pneumatic rate of rise line heat detector. Pneumatic rate of rise spot detector. Rate compensated detector. Electronic spot type heat detector.
Used to monitor large areas of buildings. Tubing that contains air that can expand. Tubing contains a diaphragm that will respond if the air expansion is greater then the preset relief vent. Tubing should not be more then 1000’ and should be in rows no more then 30’ apart and 15’ from walls.
Pneumatic rate of rise line heat detector.
Self contained single unit that monitors one specific location. Operates on same principle as pneumatic rate of rise line heat detector.
Pneumatic rate of rise spot detector.
Designed for use in areas that have regular temp changes. Has a outer sleeve with two metallic bowed struts inside. When heated at the right rate the outer sleeve expands, this cause the inner strips to touch, initiating a alarm. If the rate of rise is slow such as 5 f to 6 f per minute the expansion is slow and the inner struts can compensate. May have a predetermined temp that when reached will activate a alarm no matter the rate of rise.
Rate compensated detector.
Consist of one or more temp sensitive wires called thermistors that produce a marked changed in electrical resistance when heated. Greater temp change results in larger amounts of current flow. Can be designed as rate of rise detectors or fixed temp. Designed to bleed small amounts of current.
Electronic spot type heat detector.
Usually installed in nonresidential and large multifamily residences. Only capable of detecting, must send a signal to another alarm device.
Smoke detectors
Typically installed in single family and smaller multifamily residences. Can detect and alarm.
Smoke Alarms
Why is the smoke detector the preferred type of detector in many residences?
It will sense products of combustion much faster then a increase of temp happens.
Name two types of smoke detectors.
Photoelectric and Ionization.
Sometimes called visible products of combustion detectors. works well on all fire types. Responds quicker to smoldering fires than ionization type detectors. Automatically reset when conditions return to normal.
Photoelectric smoke detectors
Uses a beam of light that is focused across a monitored area onto a photoelectric cell. When smoke interferes with the beam it causes a decrease in electrical current initiating a alarm.
Projected beam photoelectric smoke detector.
Uses a light emitting diode (LED) to project a beam. Pass through a small chamber away from from the light source. The light normally doesn’t strike the photocell. When smoke enters the chamber the light reflects off the smoke striking the photo cell causing a alarm.
Refractory application or light scattering smoke detector.
When the particulate products of combustion (smoke) enter the chamber, they attach themselves to electrically charged molecules of air (ions), making the air within the chamber less conductive. The decrease in current flowing between the plates transmits a alarm. These respond faster to flaming fires then smoldering ones. Automatically reset when atmosphere has cleared.
Ionization Smoke Detector
How often should smoke alarm batteries be tested and replaced?
Tested = monthly Changed = 2 x year
A lithium battery in a new smoke alarm last how long?
10 years
What are three things that flame detectors (light detectors) are designed to detect?
Light in ultraviolet wave spectrum (UV detectors)
Light in infrared wave spectrum (IR detectors)
Light in both UV and IR.
Are flame detectors the fastest to respond to fires?
Yes
What may cause a false alarm of a flame detector?
welding, sunlight, other bright light sources
A flame detector will not alarm if it is blocked by what?
A opaque object.
Some single band IR detectors are sensitive to sunlight. These may be installed where?
In enclosed spaces.