Fire detection systems

Question 1

Introduction to Fire detection systems

Answer 1

a. Fire prevention and building codes require that most new structures have some sort of fire protection system installed. Currently we use the IFC Chapter 903, IBC Chapter 903, NFPA 13 and NFPA 72 for requirements
b. Understanding how these systems operate is important for fire fighter safety and effective customer service

Question 2

From a safety standpoint, why are fire detection surpression systems good?

Answer 2

i. The operations and limitations of fire detection and suppression systems (Fire Sprinklers systems are effective in controlling fires 96% of the time.)

Question 3

From a customer service standpoint, what should we be doing with regards to fire protection systems

Answer 3

i. Help dispel misconceptions about fire protection systems

ii. Advise building owners and occupants after an alarm is sounded

Question 4

What are FPS (fire protection systems) like across america?

Answer 4

i. Most areas follow the applicable NFPA standards

ii. Local fire prevention and building codes may require different types of systems for different buildings

Question 5

What are the IFC, IBC, and NFPA requirements for FPS?

Answer 5

IFC Chapter 903,
IBC Chapter 903, NFPA 13 and
NFPA 72

Question 6

What is a fire alarm and/or detection system?

Answer 6

a. A fire detection system recognizes when a fire is occurring and activates the fire alarm system
i. Alerts occupants (saving lives primary purpose)
ii. May alert the fire department
iii. May automatically activate fire suppression systems
iv. Secondary purpose is to conserve property
b. Fire alarm and detection systems can be very simple or very complex
i. These systems generally have the same basic components

Question 7

Residential fire alarm systems

Answer 7

a. Single-station smoke alarm most common type of residential fire alarm system
b. Includes both a smoke detection device and an audible alarm within a single unit
c. Millions installed in private dwellings and apartments
d. Smoke alarms can be battery-powered or hard-wired to a 110 volt electrical system
e. Up-to-date codes require new homes to have a smoke alarm in every bedroom and on every floor level
f. Many home fire alarm systems are part of security systems

Question 8

Ionization Versus Photoelectric Smoke Detectors

Answer 8

a. Ionization detectors are triggered by the invisible products of combustion
b. Photoelectric detectors are triggered by the visible products of combustion

Question 9

Fire Alarm System Components

Answer 9

a. Three basic components in a fire alarm system
i. Alarm initiation device
ii. Alarm notification device
iii. Control panel

Question 10

Fire Alarm System Control Panels

Answer 10

i. Serves as the “brain” of the system
ii. Manages and monitors the proper operation of the system
iii. Can indicate the source of an alarm
iv. Also manages primary power supply and provides backup power supply for the system
v. May perform additional functions, and may interface with other systems and facilities
vi. Vary greatly depending on age of system and manufacturer
vii. Used to silence the alarm and reset the system
viii. Many buildings have an additional display panel, called a remote annunciator in a separate location. Near the main entry way or lobby is a good location. Near the main entry way or lobby is a good location for Annunciator panels
ix. A battery in the fire alarm control panel will automatically activate when the external power is interrupted

Question 11

Alarm Initiating Devices

Answer 11

i. Components that activate a fire alarm system
ii. Manual initiation devices require human activation
iii. Automatic devices function without human intervention

Question 12

Manual initiating devices

Answer 12

i. Designed so that building occupants can activate the fire alarm system
ii. Primary manual initiation device is the manual fire alarm box, or manual pull- station
iii. Once activated, should stay in the “activated” position until it is reset
iv. Double-Action Pull Stations
1. Variation on the double-action pull-station, designed to prevent malicious false alarms, is covered with a piece of clear plastic
2. Often used in areas where malicious false alarms frequently occur

Question 13

Automatic initiating devices

Answer 13

i. Deigned to function without human intervention
ii. Can use several different types of detectors
iii. Some detectors activated by smoke or by invisible products of combustion
iv. Others react to heat, light produced by an open flame, or specific gases

Question 14

Smoke detectors

Answer 14

1. Designed to sense the presence of smoke
2. Commonly found in schools, hospitals, businesses, and commercial occupancies with fire alarm systems
3. Most common are ionization (Invisible products of combustion) photoelectric detectors

Question 15

Heat detectors

Answer 15

1. Can provide property protection, but cannot provide reliable life safety protection
2. Generally used in situations where smoke alarms cannot be used
3. Often installed in unheated areas
4. Generally very reliable an less prone to false alarms than smoke alarms

Question 16

Fixed tempurature detectors

Answer 16

a. Designed to operate at a preset temperature

b. Usually use a metal alloy that will melt at the preset temperature

Question 17

Rate of rise detectors

Answer 17

a. Will activate if the temperature of the surrounding air rises more than a set amount in a given period of time
b. Most rate-of-rise heat detectors are self-restoring
c. Generally respond faster to most fires than fixed-temperature heat detectors

Question 18

line heat detectors

Answer 18

a. Use wires or a sealed tube to sense heat
b. One type has two wires inside, separated by an insulating material
c. Another type measures changes in the electrical resistance of a single wire as it heats up
d. The tube-style line heat detector has a sealed metal tube filled with air or a nonflammable gas

Question 19

Flame detectors

Answer 19

1. Specialized devices that detect the electromagnetic light waves (Infrared or Ultraviolet) produced by a flame
2. Typically found in places where early detection and rapid reaction to a fire is critical
3. Complicated and expensive
4. Arc welding can cause accidental activation of ultraviolet flame detectors

Question 20

Gas detectors

Answer 20

1. Calibrated to detect the presence of a specific gas
2. Needs regular calibration
3. Usually found only in specific commercial or industrial applications
4. Gases released by a fire that a detector would sense are Carbon Monoxide, Carbon Dioxide, Hydrogen Chloride, Hydrogen Cyanide, Hydrogen Fluoride and Hydrogen Sulfide

Question 21

Air Sampling detectors

Answer 21

1. Continuously capture air samples and measure the concentrations of specific gases or products of combustion

Question 22

Alarm Initiation By Fire Suppression Systems

Answer 22

a. Systems alerts building occupants and the fire department to a possible fire
b. Water Flow Alarm ensures that someone is aware water is flowing from a sprinkler head or when a standpipe valve is opened

Question 23

False, Unwanted, and Nuisance Alarms

Answer 23

a. Malicious False Alarms
i. Caused by individuals who deliberately activate a fire alarm when there is no fire
b. Unwanted Alarms
i. Occur when an alarm system is activated by a condition that is not really an emergency
c. Nuisance Alarms
i. Caused by improper functioning of an alarm system or one of its components

Question 24

Alarm Notification Appliances

Answer 24

a. Produce an audible signal when fire alarm is activated ( Bells, horns, speakers)
b. Some signals play a recorded announcement in conjunction with the temporal – 3 pattern
c. Many new systems incorporate visual notification devices

Question 25

Other fire alarm functions

Answer 25

a. May also control other building functions, such as air handling systems, fire doors, and elevators b. Responding fire personnel must understand which building functions are being controlled by the fire alarm

Question 26

Fire Alarm annunciation systems

Answer 26

a. Almost all alarm systems are now zoned to some extent b. In a coded system, zone is identified not only at the alarm control panel but also through audio notification device c. Systems can be broken down into four categories, non-coded alarm, zoned non-coded alarm, zoned coded alarm, and master-coded alarm

Question 27

Non-coded alarms

Answer 27

i. Control panel has no information indicating where in the building the fire alarm was activated ii. Typically sounds a bell or a horn iii. Fire department personnel must search the entire building to find which initiation device was activated

Question 28

Zoned non-coded alarms

Answer 28

i. Most common type of system, particularly in newer buildings ii. Building divided into multiple zones, often by floor or by wing iii. Alarm control panel indicates in which zone the activated device is located

Question 29

Zoned Coded alarms

Answer 29

i. In addition to having all the features of a zoned alarm system, also indicates which zone has been activated over the announcement system ii. Hospitals often use this type of system

Question 30

Master coded alarms

Answer 30

i. Audible notification devices for fire alarm also are used for other purposes ii. Most of these systems have been replaced by modern speaker systems that use the temporal-3 pattern fire alarm signal and have public address capabilities

Question 31

Fire Department notification systems

Answer 31

Fire alarm systems can be broken down into four classifications, based on how the fire department is notified of an alarm a. Local alarm system b. Remote station system c. Proprietary or Auxiliary system d. Central station

Question 32

Local alarm system

Answer 32

1. Does not notify the fire department | 2. The alarm sounds only in the building to notify the occupants

Question 33

Remote station system

Answer 33

1. Sends signal directly to fire department or to another monitoring location via a telephone line or a radio signal

Question 34

Auxilary system

Answer 34

1. Building’s fire alarm system is tied into a master alarm box located outside

Question 35

Proprietary system

Answer 35

1. Building’s alarms connected directly to monitoring site owned and operated by building owner

Question 36

Central Station system

Answer 36

1. Third-party, off-site monitoring facility that monitors multiple alarm systems 2. An activated alarm transmits a signal to the central station by telephone or radio 3. Personnel at the central station then notify the appropriate fire department of the fire alarm

Question 37

Fire Supression systems

Answer 37

a. Include automatic sprinkler systems, standpipe systems, and specialized extinguishing systems such as dry chemical systems b. Understanding how these systems work is important because they can affect fire behavior

Question 38

Automatic sprinkler systems

Answer 38

i. One of the major advantages of a sprinkler system is that it can function as both a fire detection system and a fire suppression system ii. Closed valves, inadequate water supply, blocked heads, fire load changes, partial protection and poor maintenance are reasons systems fail iii. Sprinkler system defined is “ A system of pipes, valves, water, and heads, which operate automatically to control or extinguish fire, initiate an alarm, save lives and property”

Question 39

Automatic Sprinkler System Components

Answer 39

i. Four major components 1. Automatic sprinkler heads 2. Piping 3. Control Valves 4. A water supply, which may or may not include a fire pump

Question 40

Automatic Sprinkler Heads

Answer 40

1. The working ends of a sprinkler system 2. Composed of a. A body, which includes the orifice (openings) b. A release mechanism that holds a cap in place over the orifice c. A deflector that diverts the water in a spray pattern

Question 41

iii. Frangible Sprinkler Heads

Answer 41

1. Use a glass bulb filled with glycerin or alcohol to hold the cap in place a. As the bulb is heated, the liquid absorbs the air bubble and expands until it breaks the glass, releasing the cap

Question 42

Chem-pellet sprinkler heads

Answer 42

1. Use a plunger mechanism and a small chemical pellet to hold the cap in place a. Pellet will liquefy at a preset temperature b. When pellet melts, liquid compresses the plunger, releasing the cap and allowing the water to flow

Question 43

Special sprinkler heads

Answer 43

1. Designed for special applications a. Covering large areas b. Discharging the water in extra-large droplets 2. ESFR sprinkler heads have improved heat collectors to speed up response and ensure rapid release

Question 44

Deluge heads

Answer 44

1. Easily identifiable, because they have no cap or release mechanism 2. Orifice is always open 3. Only used in deluge sprinkler systems 4. Deluge systems are designed to protect hazardous occupancies

Question 45

Temperature ratings

Answer 45

a. Typical rating for sprinkler heads in a light hazard occupancy would be 165 degrees F. (74C) b. Rating should be stamped on the body of the sprinkler head c. Temperature rating must match the anticipated ambient air temperatures d. Spare heads that match those used in the system should always be available on-site e. Uncolored or black sprinkler heads have an operating temperature of 135-170 degrees F.

Question 46

Sprinkler piping

Answer 46

a. Network of pipes that delivers water to sprinkler heads b. Includes main water supply lines, risers, feeder lines, and branch lines c. Usually made of steel d. Plastic pipe sometimes used in residential systems

Question 47

Valves

Answer 47

a. A sprinkler system includes several different valves such as: i. Main water supply control valve ii. Alarm valve iii. Other, smaller valves used for testing and service b. All of the valves play a critical role in the design and function of the system

Question 48

Water supplies

Answer 48

a. Water may come from municipal water system, on-site storage tanks, or static water sources b. Water supply must be able to handle demand of the sprinkler system, as well as the needs of the fire department c. Preferred water source for a sprinkler system is a municipal water supply d. Retard chambers can be added to fire sprinkler system risers to help reduce false alarms due to momentary water surges

Question 49

Fire pumps for sprinklers

Answer 49

a. Used when the water comes from a static source | b. May also be used to boost the pressure in some sprinkler systems, particularly for tall buildings

Question 50

Fire department connections FDC

Answer 50

a. Allows the department’s engine to pump water into the sprinkler system b. Used as either a supplement or the main source of water c. Water Flow Alarms d. Most systems incorporate a mechanical flow alarm called a water-motor gong e. When system is activated and main alarm valve opens, water is fed through a pipe to a water-powered gong located outside the building

Question 51

Types of automatic sprinkler systems

Answer 51

a. Divided into five categories i. Wet sprinkler systems ii. Dry sprinkler systems iii. Pre-action sprinkler systems iv. Deluge sprinkler systems v. Residential vi. Coverage of systems could be complete or partial

Question 52

Wet sprinkler systems

Answer 52

i. Most common and the least expensive type of automatic sprinkler system ii. Piping always filled with water iii. As sprinkler head activates, water is immediately discharged onto the fire iv. Major drawback, cannot be used in areas where temperatures drop below freezing v. Will also flow water if a sprinkler head is accidentally opened or a leak occurs in the piping

Question 53

Dry sprinkler systems

Answer 53

i. Operate much like wet sprinkler systems, except that the pipes are filled with pressurized air instead of water. Used in areas subject to freezing ii. A dry-pipe valve keeps water from entering the pipes until the air pressure is released

Question 54

Pre-action sprinkler systems

Answer 54

i. Similar to a dry sprinkler system with one key difference 1. A secondary device (smoke or heat detector) must be activated before water is released into the sprinkler piping. 2. When the system is filled with water, if functions as a wet sprinkler system

Question 55

Deluge sprinkler systems

Answer 55

i. Water flows from all of the sprinkler heads as soon as the system is activated ii. Does not have closed heads that open individually at the activation temperature, all of the heads in a deluge system are always open

Question 56

Residential sprinkler systems

Answer 56

a. Relatively new, but many homes now being built include them b. Typically use smaller piping and sprinkler heads with smaller orifices and less water discharge

Question 57

Shutting down sprinkler systems

Answer 57

a. Order to shut down sprinkler system should come only from the IC b. In most cases, system can be shutdown by closing main control valve such as one of the following, OS&Y, PIV, WPIV, or PVIA c. Placing a wooden wedge or a commercial sprinkler stop into the sprinkler head can quickly stop the flow of water i. This will not work with all types of heads

Question 58

Standpipe systems

Answer 58

a. Network of pipes and outlets for fire hoses built into a structure to provide water for firefighting purposes b. Usually used in high-rise buildings, although they are found in many other structures as well

Question 59

Standpipe classification

Answer 59

c. Class I Standpipes i. Designed for use by fire department personnel only ii. Each outlet has a 2 ½” male coupling and a valve to open the water supply after the hose is connected d. Class II Standpipes i. Outlets generally equipped with a length of 1 ½” single-jacket hose pre-connected to the system ii. Intended to enable occupants to attack a fire before the fire department arrives, but safety and effectiveness is questionable e. Class III Standpipes i. Have the features of both Class I and Class II standpipes in a single system ii. Have 2 ½” outlets for fire department use as well as smaller outlets with attached hoses for occupant use iii. Fire fighters should use only the 2 ½” outlets, even if they are using an adapter to connect a smaller hose

Question 60

Water flow in standpipe systems

Answer 60

a. Actual flow depends on the water supply, as well as on the condition of the piping system and fire pumps b. Flow-restriction devices or pressure-reducing valves often installed at outlets to limit pressure and flow i. If not properly installed and maintained, these devices can cause problems for fire fighters

Question 61

Water supplies in standpipe systems

Answer 61

a. Wet standpipe systems in modern buildings are connected to a public water supply with an electric or diesel fire pump to provide additional pressure b. Most dry standpipe systems do not have a permanent connection to a water supply, so the FDC must be used to pump water into the system

Question 62

Special extinguishing systems

Answer 62

a. Specialized extinguishing systems are often used in areas where water would not be an acceptable extinguishing agent - dry chem - wet chem - clean agent - Carbon dioxide

Question 63

Dry chem extinguishing systems

Answer 63

i. Use the same types of finely powdered agents as dry chemical fire extinguishers ii. Agent kept in self-pressurized tanks or in tanks with an external cartridge of carbon dioxide or nitrogen that provides pressure when the system is activated

Question 64

Wet chem extinguishing systems

Answer 64

i. Used in most new commercial kitchens ii. Use a proprietary liquid extinguishing agent 1. Much more effective on vegetable oils than the dry chemicals used in older kitchen systems

Question 65

Clean agent extinguishing systems

Answer 65

i. Often installed in areas where computers or sensitive electronic equipment are used, or where valuable documents are stored ii. Nonconductive and leave no residue iii. Halogenated agents or carbon dioxide are generally used iv. Operate by discharging a gaseous agent into the atmosphere at a concentration that will extinguish a fire v. If there is a fire, the clean agent system should be completely discharged before fire fighters arrive vi. Should be tied to building’s fire alarm system and indicated as a zone on the control panel 1. Alerts fire fighters that they are responding to a situation where a clean agent has discharged

Question 66

Carbon Dioxide extinguishing systems

Answer 66

i. Designed to protect a single room or a series of rooms | ii. Should be connected to the building’s fire alarm system

Question 67

Initiating devices for special extinguishing systems

Answer 67

i. Fusible links are placed above the target hazard to activate extinguishing systems ii. Manual discharge pull station is also provided so that workers can activate the system if they discover a fire

Question 68

Extinguishing systems summary

Answer 68

a. All firefighters must have a general understanding of how fire protection systems function b. Firefighters will respond to more false alarms in their careers than actual fires c. Although it is not the firefighter’s job to maintain fire protection systems, firefighters should be able to advise the public on how to restore systems to service d. Regardless of how sophisticated a fire protection system is, a serious fire can still occur e. It is every firefighter’s job to try to limit water damage from the activation of a sprinkler system f. Firefighter’s must understand the potential shortcomings of using a standpipe system to prevent injuries and fatalities