BY BILLY NIGZUS

TERM 1 10-10-14

FIRE ALARMS

WHAT ARE FIRE ALARMS ?Fire alarms are a device or a system that alert people when there is a fire.

• A device could be a battery operated smoke detector.• A system is a group of devices such as pull stations, smoke detectors, and a system

panel.

How do you activate the system you ask? There are 2 types of devices that make the alarm sound, there is a pull station, and a smoke detector.

• A pull station is a device on the wall you pull when there is a fire.• A smoke detector is a device on the ceiling that when it senses smoke it activates

the alarm.

HOW DOES THE FIRE DEPARTMENT KNOW ABOUT THE ALARM GOING OFF ?

When you set off the alarm several things happen:

• When you pull the pull station it throws a switch which completes a circuit.

• A signal goes to the panel and sets off the zone where the pull station is.

• Two things happen

• the alarms go off in the building

• there is a phone line from the panel to the fire alarm company

• the alarm company’s 24 hour fire alarm tracker then calls dispatch and

they set a tone out to the fire department that there is a fire call.

TYPES OF SMOKE DETECTORS

If there is a fire and no one is around to pull the alarm, what

happens?

• A smoke detector acts the same as a pull station when it detects smoke.

• There are two types of smoke detectors

• Ionization: better at detecting fast fires

• Photoelectric: better at detecting smoldering fires

A VIDEO ON PHOTOELECTRIC VS IONIZATION SMOKE DETECTORS

HTTPS://WWW.YOUTUBE.COM/WATCH?V=ZROLXH8GUCU

• 6:34

OTHER TYPES OF DETECTORS

Heat detectors

• They sense a rise in temperature usually above 125oF

• Usually used where people are not there for 24 hours

• Places such as garage, basement, or attic

CO detectors

• They sense carbon monoxide

• It is a odorless, tasteless, colorless gas that will kill you.

• Produced by burning fuel (Wood, Oil, and Propane, etc.)

• Two common types of CO detectors

• Combination with smoke detector (does both at the same time)

• Plug in CO detectors (CO only but easy to install)

EXPERIMENT What will we learn?

• How fire alarms work?

• How do they activate

• Manually by pull station

• Automatically by smoke detector

• What happens?

• The alarm will go off inside the building

• The alarm panel calls dispatch

SOURCES

YOUTUBEHTTPS://WWW.YOUTUBE.COM/WATCH?V=ZROLXH8GUCU

GOOGLE IMAGES

NFPA, NATIONAL FIRE PROTECTION ASSOCIATION