chapter 44_fire suppression.pdf

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Chapter 44

Fire-Suppression Systems

Heald cnst 170



Fire Codes

• NFPA promotes Uniform Fire Code• Building design, hazardous materials,regularity procedures, code enforcement,and other fire-related activities

• ICC International Fire Code

• Equipment, hazardous materials, firesafety, and fire protection requirements

• UL tests equipment and issuesreports



How do fire sprinklers

work?

Automatic fire sprinklers areindividually heat-activated andattached to a network of piping

with water under pressure.

When the heat of a fire raises thesprinkler temperature to itsoperating temperature (usually186 deg F), a solder link will melt

or a liquid-filled glass bulb willshatter.

Then the sprinkler will open,releasing water and sounding analarm.

By acting automatically at theorigin of a fire, sprinklers preventa fire from growing to adangerous size.



Sprinkler Systems

There are 4 main types of systems

• Wet Pipe

• Dry Pipe

• Pre-Action

• Deluge



A dry pipe

system haspressurized air

in the pipes.Water flows to

the sprinklersAFTER the

alarm issounded.

Used wherepipes may

freeze.



A wet pipe

systemmaintains

water underpressure in the

pipes at alltimes, but onlythe sprinklers

over the fireare activated.



A deluge

systemactivates allthe sprinklerheads in an

area at thesame time.



A pre-action

pipe systemis a dry pipe

system whereonly the

sprinklers overthe fire areactivated.



Exposed sprinkler piping



Wet Pipe Systems

General Information

• Most common system

• Most Inexpensive

• Require the least maintenance



Typical Wet Pipe System



Wet Pipe System ComponentsSprinkler Heads

• Fusible link, glass bulb,chemical pellet

• Upright, Pendant, Sidewall

• Discharge water over

designed area



Dry Pipe Systems

• Necessary in areas exposed to cold temperatures

• More expensive• Requires more maintenance



Dry Pipe System Components

Dry Pipe Valve (Clapper)

• Division between supply

water and system AIR

• Surface area inside valve

allows for low air pressure to

keep clapper from opening

• Fused sprinkler head, air

released, supply water opensclapper



Would sprinklers prevent this?



Siamese connection used by the firedepartment to connect a supplementalsource of water to the building’s fire-

suppression system.



A sprinkler alarm sounds a warningwhen the sprinkler system is activated.



Fire Strobesprovide both visual and sound alarms



Foam fire-suppressant systems

• Used when water is not effective alone

• Foams are masses of air-filled or gas-filled bubbles



Foam fire-suppressant systemsA Foam “Dump”: Use in aircraft hangars.



Gas fire-suppression systems

• Able to flood areas, suppressing fire with little

harm to contents.• Especially important in areas with sensitive

equipment such as computer rooms,

commercial aircraft, telephone exchanges, andlibraries.

• Gas is usually carbon dioxie or Halon 1301.

• Harmful to humans and animals: causessuffocation.



Dry Chemical Systems

• Do not penetrate burning materials but

remain on surface and smother fire

• Chemicals frequently used include sodiumbicarbonate, potassium chloride, and

monoammonium phosphate

• Effective on flammable liquid, electricalmaterials, and ordinary combustible materials



Manual Fire-Suppression

• Fire hose stations on each floorconnected to water pipingsystem.

• Standpipes added when waterpressure is insufficient for upperfloors.

• Pipe or tank on roof storeswater and provides potablewater preserve.



manually operated fire hose station



THEEND

chapter 44_fire suppression.pdf

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