Chapter 12 Protective Systems

Introduction Protective systems help guard lives and property Detection systems detect presence of fire and alert occupants and/or fire department Suppression systems help firefighters in controlling fires Detection systems are varied Three systems can be combined to form protective ensemble 12.2

Detection Systems Designed to notify people Simple systems warn person to recognize danger Complex systems use series of devices to automatically detect event and initiate alarm 12.3

People or Manual Systems People can alert other people and call fire department after discovering a fire Requires a person to discover a fire and pull the alarm Two typical problems: –Person must be present, awake, and alert –Systems are local only 12.4

Heat Detectors Detect heat of fire at fixed temperature or as rising temperature builds at rapid rate Can be used as part of a suppression system Slow to detect fires Inexpensive with low rate of false alarms Spot type or line type 12.5

12.6 Figure 12-1 Rate-of-rise heat detector.

Smoke Detectors Smoke and toxic gases are leading killers of people in residential structure emergencies Most prevalent automatic detection system Can be hard wired, battery operated, or a combination Ionization detectors are the most common type 12.7

Gas Detectors Designed to find presence of certain gases prior to reaching a concentration Carbon monoxide detectors for home are popular CO detectors function using several different methods Most provide an early warning alarm 12.8

Combination Smoke/Carbon Monoxide Detectors Simplify things for the builder Can make discerning situation more difficult for firefighters –Detector manufacturers have added different alarms and colored lights for each situation –Excited homeowner may not correctly distinguish between the two –Some manufacturers have added voice prompts 12.9

Flame Detectors Detect flames or lightwaves –Ultraviolet –Infrared –Combined ultraviolet-infrared Very sensitive and quick to alarm Used to protect petroleum and chemical facilities 12.10

Sprinkler Systems Designed to automatically distribute water through sprinklers Usually in the ceiling Most sprinkler heads detect heat Highly effective 12.11

Sprinklers and Life Safety Originally designed in late 1800s Intent was to protect business and industrial property Almost 100 percent effective Failure due to two reasons: –Improper maintenance –Inadequate water supply 12.12

Sprinkler Head Design and Operation Sprinkler heads are the key component Deluge-type have separate detection devices Come in many designs: –Old-style sprinklers –New style or standard sprinklers May require: –Corrosion-resistant heads –Dry head with extension piping –Rack storage head, decorative head 12.13

Types of Sprinkler Systems Some sprinkler systems protect: –Homes or apartment buildings –Buildings with highly sensitive electronic equipment –Homes and businesses in areas subject to harsh winter conditions 12.14

Specialty Sprinkler Systems Include some combination-type sprinkler system and systems that cannot meet standards May have inadequate water source or supply Fire departments must be familiar with limitations and intended protection strategy 12.15

Wet Pipe Systems Automatic sprinklers attached to pipes with water under constant pressure Quick response Simplest sprinkler system in design and operation Figure Wet pipe sprinkler system.

Dry Pipe Systems Air under pressure replaces water Uses a dry pipe valve More complex in design than a wet pipe system Harder to return to service after activation Figure Dry pipe system schematic.

Deluge Systems Designed to protect areas that may have fast-spreading fire Must interface with a detection system Causes tremendous quantities of water to flow 12.18

12.19 Figure Deluge system schematic: 1, OS&Y valve; 2, deluge valve with basic trim; 3, solenoid valve and electric actuation trim; 4, pressure alarm switch; 5, water motor alarm; 6, spray nozzles or open sprinklers; 7, deluge releasing panel; 8, electric manual control stations; 9, fire alarm bell; 10, trouble horn; 11, heat detectors. (© Copyright Simplex Grinnell. All rights reserved.)

Pre-action Systems Similar to dry pipe and deluge system Closed piping and heads with air under no or little pressure Water flows from separate fire detection system Found in computer rooms, museums, or buildings storing historical items 12.20

12.21 Figure Pre-action system schematic: 1, OS&Y valve; 2, deluge valve with basic trim; 3, check valve; 4, solenoid valve and electric actuation trim; 5, water pressure alarm switch; 6, 1.5-psi low air pressure alarm switch; 7, 1.5-psi supervisory air pressure control; 8, water motor alarm; 9, automatic sprinklers; 10, deluge releasing panel; 11, electric manual control stations; 12, fire alarm bell; 13, trouble horn; 14, heat detectors. (© Copyright Simplex Grinnell. All rights reserved.)

Residential Systems Smaller and more affordable version of wet or dry pipe systems Water supply combined with domestic water supply Designed for one or a few heads Use lighter and smaller piping First suppression system to use plastic piping Some use antifreeze 12.22

Sprinkler Systems Connections and Piping Comprise most of the components of sprinkler system Water comes from public or private water Secondary source supplied via fire department connection Firefighter should be able to connect supply line to fire department connection 12.23

Control Devices for Sprinkler Systems Three main control devices: –Outside stem and yoke valve (OS&Y) –Post indicator valve (PIV) –Wall indicator valve (WIV) 12.24

Returning Sprinkler Systems to Service Most departments no longer provide testing or service Once fire is extinguished, firefighters should leave at least one charged hoseline in place Simplest and quickest way to stop water flow from sprinkler head is to insert a stop Once system is shut down, heads may be replaced Fire watch established until system is restored 12.25

12.26 Figure Sprinkler tongs and wood wedges stopping sprinkler flow.

Standpipe Classifications Designed to allow firefighters to fight fires in larger buildings by pre-piping water Classified according to intended user –Class I –Class II –Class III Differentiated based on water supply 12.27

12.28 Figure Class II standpipe system.

Standpipe System Connections and Piping Range from very simple to highly complex –Piping –Outlets with hose and other attachments –Valves –Fire department connection –Any monitoring devices Standpipe valves similar to vales used on sprinkler systems 12.29

Alarms for Standpipes and Sprinklers Found in most sprinkler and standpipe systems Most protective systems require monitoring to prevent tampering Monitoring alarm company notifies fire department about fires –Company responds on its own to tampered alarms 12.30

Other Protective Systems Many other types are used today Some are rather simple: –Grill –Fryer –Ductwork Others are extremely complex and designed to prevent or suppress an explosion All firefighters responding need to be familiar with operation of complex systems 12.31

Local Application and Hood Systems One of the most common types of protective systems is a local application system Protects only a certain portion of building Also used in: –Laboratory hoods –Paint booths –Small hazardous locations Use heat-sensitive device or manual switch for activation 12.32

Total Flooding Systems Used to protect an entire area, room, or building Discharges an extinguishing agent Effective as long as proper amount discharges 12.33

Fire Department Operations with Protective Systems Standpipe, sprinkler, and other protective systems are part of fire department strategy plan Strategy recognizes community’s hazards Protective systems required when properties or processes create hazards beyond certain limits Protective systems can be separate components 12.34

Standpipe Operations Start with establishing water supply to fire department connection Pump operator should immediately charge standpipe system Personnel should check annunciator panel Fire crews should stop at least two floors below reported fire level Personnel should have full protective equipment, standpipe pack, and forcible entry equipment 12.35

Sprinkler System Operations Begin with investigation of building First arriving officer check annunciator panel Pump operator should charge sprinkler system Personnel should advance hoseline into fire area If no fire is found, officer may direct firefighters to stop sprinkler flow 12.36

Detector Activation Operations Histories of false alarms have caused firefighters to take a less than ready approach Firefighters must treat all fire alarm activities as an actual fire Firefighters should dismount wearing full PPE, SCBA, and carry necessary tools and radio At commercial structures, first arriving crew checks annunciator panel Do not turn off alarms prematurely 12.37

Operations for Other Protective Systems Local SOPs should address operations for: –Total flooding –Foam –Dry chemical –Other unique systems Clean up of foam is not responsibility of fire department, but occupants must be warned Activation of suppression systems may cause secondary damage 12.38

Lessons Learned Protective systems designed to automatically detect or suppress a fire –Apply water or other extinguishing agents Sprinkler systems used for detection and suppression –Apply water or foam Standpipe systems facilitate manual fire suppression Fire department operations at buildings with protective systems outlined in SOPs 12.39