Tolles Fire Chapter 37: Fire Detection, Protection and Suppression Systems

Blake Schneider
Flashcards by Blake Schneider, updated more than 1 year ago
Blake Schneider
Created by Blake Schneider over 3 years ago
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Flashcards on Fire Chapter 37: Fire Detection, Protection and Suppression Systems, created by blakeschneider on 04/06/2017.
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Difference between Ionization and Photoelectric smoke detectors Ionization: triggered by invisible products of combustion. Has radioactive material that releases charged particles which creates current between two plates. Charged products of combusion interrupt this flow and set alarm. Most common and inexpensive. Susceptible to false alarms from cooking fumes and steam. Photoelectric: triggered by visible products of combustion. Uses light source to create a beam. Once smoke flows through light beam, light redirects and hits a photocell which sounds alarm. Less common, more expensive. More responsive to slow burning fires. Less prone to false alarms. Require more current to operate (usually connected to 110v power source)
The 3 main fire alarm system components Inititiation device Notification device Control panel
Most common type of residential fire alarm system Single-station smoke alarm
3 common types of Manual Initiation Devices Manual pull-station Single-action pull-station Double-actoin pull-station
Heat detectors are designed to operate in these 2 ways Fixed temperature (typically 135F) Rate-of-rise (typically greater than 12F per minute)
Flame detectors work in this manner They detect the elecromagnetic light waves produced by a flame.
This type of detector is often installed in the return of air ducts of large buildings. Air sampling detector
Malicious false alarm A deliberately activated fire alarm when there is no fire.
Unwanted alarm Whan an alarm is activated by a condition that is not really an emergency (cooking or steam from shower).
Nuisance alarm Caused by improper functioning of an alarm system.
Differences between cross-zoned and verification smoke detection systems Cross-zoned: Initial detector will set off a trouble alarm. A second detector is needed to activate before the actual fire alarm will sound. Verification: A delay of 30-60 seconds separates activation and notification. System will recheck detector after this time. If condition has cleared, system will be returned to normal. If trouble is still detected, alarm will activate.
Noncoded Alarm System Control panel does not give any information where the fire alarm was activated. Up to firefighters to find which device was activated.
Zoned Noncoded alarm system Most common encountered by firefighters. Building is divided into multiple zones, usually by floor or wing. Control panel indicates qhich zone the activated device is located.
Zoned Coded Alarm Includes an audible indication of the activated zone over an announcement system in addition to the standards features of a zoned system.
Master-Coded alarm Older and rarely installed, this system is a multi-use audible notification device (changing of classes, janitorial request, & other notifications).
Local alarm system Notifies only the building's occupants
Remote station system Sends signal directly to FD or to another monitoring location via telephone or radio.
Auxiliary systems Public fire alarm box system. Largely replaced by more modern communication devices.
Proprietary systems Alarms are connected directly to monitoring site that is owned by the buildings owner. Often at multi-building facilities such as universities or industrial complexes. This monitoring site is staffed at all times.
Central stations Third-party off-site facility that monitors multiple alarm systems. Like ADT etc...
Water-motor gong An alarm that signals when water is flowing in the sprinkler system.
3 main types of sprinkler head mounting positions Upright Horizontal Pendant
4 common types of sprinkler heads Fusible-link - uses metal alloy that melts to release water . Frangible-bulb - glass bulb filled with glycerin or alcohol with a bubble that expands when heated, releasing water . Chemical-pellet - Uses a plunger mechanism with a chemical pellet to hold the cap in place. Pellet liquefies when temp reaches a preset point. . Deluge head - No release mechanism
3 common water supply control valves Outside stem and yoke (OS&Y) Post indicator valve (PIV) Wall post indicator valve (WPIV)
Outside stem and yoke valve (OS&Y) Has a stem that moves in and out as valve opens and closes. Stem out = valve open. Stem in = valve closed. Often found in mechanical room, or where water supply enters the building. May be outside in warmer climates.
Post indicator valve (PIV) Has an indicator that reads open or shut, depending on position. Usually in open area outside building. Requires a wrench (usually attached to the side of the valve).
Wall post indicator valve (WPIV) Similar to PIV but designed to be mounted on the outside wall of a building.
Fire department connection (FDC) An exterior connection that allows the FD's engine to pump water into the sprinkler (and sometimes standpipe) system. Usually 2.5 inch couplings.
Wet vs. Dry sprinkler system Wet: Most common & least expensive. Always filled with water. A disadvantage is that it cannot be used in areas where building temperatures drop below freezing. Water will also flow if a sprinkler head is accidentally opened or a leak occurs. Dry: Similar to wet, only that the pipes are filled with pressurized air rather than water.
Class 1 Standpipe For FD use only. Uses a 2.5 inch coupling. Often located inside a cabinet. FF must bring hose with them. System must be able to supply enough water to operate attack lines.
Class 2 Standpipe Designed for use by building occupants. Usually have 1.5 inch hose preconnected to the system. Intended to enable occupants to attack a fire before the FD arrives. FF should not use class 2 standpipes to fight fire (may be inadequate).
Class 3 standpipe Has class 1 & 2 standpipe features in the same system.
At the top of a building, many standpipe systems deliver water at _____ psi 65
Dry chemical extinguishing system Uses the same types of agents as dry-chemical fire extinguishers
Wet-chemical extinguishing system Used in most new commercial kitchens. Easier to clean up than dry-chemical systems.
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