Alarm Systems And Smoke Alarms 030104h Flashcards
What are the common types of perimeter sensing devices?
Objective 1 Page 3 - 10
Magnetic Reed Switches
Roller Ball Contact Switches
Window Screen Contacts
Glass Break Detectors
What are the two types of Magnetic reed switches?
Objective 1 Page 4
Surface mount (usually for sealed windows.)
Recessed (Usually for doors and higher security areas.)
Are inexpensive to produce and have a life cycle of up to 10 million operations.
What kind of switch is used for overhead doors and why?
Objective 1 Page 5
Larger size magnetic reed contacts.
Overhead doors have less accurate alignment due to flexible weather stripping so they require stronger magnet sensors.
What can happen if the magnet for a switch is not installed properly?
Objective 1 Page 6
May cause false alarms since the switch will be very sensitive to any movement.
What are the two reasons roller ball switches are not very popular anymore?
Objective 1 Page 7
Costs more to produce them.
More susceptible to dirt infiltration which causes them to fail more frequently.
What are the two ways a window screen protector will sense an intruder?
Objective 1 Page 8
If the screen is removed, magnetic reed contacts will open.
If the screen is cut, parallel wires will also be cut and break the alarm circuit.
What are the types of glass break sensors?
Objective 1 Page 8 - 10
Shock detectors
Acoustic sound pattern detector
Dual sensor that combines both.
How do shock detectors work and where are they mounted?
Objective 1 Page 8 & 9
Senses rapid change in air pressure when a window is broken.
Mounted on the glass pane.
How do Acoustic Sound Pattern Detectors (Shatter Switch) work?
Objective 1 Page 9
Programmed with glass breaking sound and is always listening for that sound pattern.
Should be mounted pointing at the glass they are protecting.
How many wires does a dual technology glass break sensor require?
Objective 1 Page 10
4 Wires Total.
2 wires(black & red) supply dc power.
2 wires(green & yellow) control signalling.
What are some examples of internal sensing devices?
Objective 1 Page 11 & 12
Microwave Motion detector (Does not use heat. Act similar to a radar.)
Passive Infrared Detector (Uses heat)
Dual or Triple Hit Passive Infrared Detectors.
What locations will wireless detectors not work very well?
Objective 1 Page 12
Anywhere that may block the transmitting signals like a chimney or metal duct.
What is the CPU for in a security system?
Objective 2 Page 14
Central processing unit.
Is the brain of the system. Operates on extra-low voltage and has a battery backup.
Can be programmed to control each zone in a location differently.
What are the three types of zone loops?
Objective 2 Page 15
Normally Open loop
Normally Closed Loop
Monitored Loop (Supervised)
What is the most common zone loop type?
Objective 2 Page 15
Monitored Loop
How does a monitored loop work?
Objective 2 Page 15
Utilizes an end of line resistor that has a small current going through it. A break in the circuit by tampering or faulty wire will send a trouble signal back to the CPU.
What are the types of signalling devices?
Objective 2 Page 16
Audible (Sirens, Bell)
Visual (Strobe Lights)
What voltage do residential alarm systems generally operate at?
Objective 2 Page 17
They are considered a class 2 circuit and operate at 6 to 12 V.
What two locations are common for Sirens to be installed in?
Objective 2 Page 17
Cold Air Returns
Attic Spaces.
Both have the ability to resonate the sound.
What are the two types of smoke alarms?
Objective 3 Page 19
Ionization Type (Product of Combustion Detector)
Photoelectric or Light Obscuration Type.
What are ionization type smoke alarms best for?
Objective 3 Page 20
Flaming fires.
What are photoelectric type smoke alarms best for?
Objective 3 Page 20
Smoldering fires
What locations are smoke alarms installed in?
Objective 3 Page 21
On each floor on or near the ceiling.
In each sleeping room.
In hallways outside sleeping rooms.
Between bedrooms and rest of the floor.
What regulates the installation of smoke alarms in dwelling units including location and interconnection?
Objective 3 Page 21
Alberta Building Code.
What three things are required for smoke alarms when installed?
Objective 3 Page 22
Wired permanently with no disconnect means between the smoke alarm and circuit breaker.
Provided with a backup battery that can maintain normal condition for 7 days followed by a 4 minute alarm condition.
Interconnected so that if one alarm is triggered the others will be set off as well.
Wireless interconnection of smoke alarms meets Alberta Building Code requirements.
How many wires does each smoke alarm need?
Objective 3 Page 22
Three.
Black and White for power.
Another coloured wire as a traveler for communication.
How does one smoke alarm communicate with the others when an alarm condition occurs?
Objective 3 Page 22
9V signal is sent through the traveller to other interconnected devices.
Can a smoke alarm be on a circuit with a GFCI?
Objective 3 Page 22
Yes as long as they have a backup battery.
Should smoke alarms be wired to normal lighting circuits?
Objective 3 Page 22
Yes.
If wired with circuits that if tripped off it would be noticed is a good safety practice.
What are the three components of a basic fire alarm system?
Objective 4 Page 26
Fire Alarm Control Panel
Manual Pull Station
Audible Signal Device
What are the four conditions a fire alarm system can be in?
Objective 4 Page 27
Normal (low current)
Trouble (no current)
Alarm (high current)
Supervisory.
What is the only condition that cannot be cleared at the panel?
Objective 4 Page 27
Supervisory.
Why must each conductor within a fire alarm system be independently terminated?
Objective 4 Page 28
To ensure that any time a terminal or splice is opened, the supervisory current is interrupted and a trouble signal is sent to the control panel.
What organization sets the standards for smoke alarms in Canada?
Objective 3 Page 20
Underwriters Laboratory
How long must the back up battery in a smoke alarm operate for?
Objective 3 Page 22
normal condition for 7 days followed by a 4 minute alarm condition.
What are the two categories of devices forming part of a fire alarm system?
Initiating and Signalling devices.
What type of circuit are residential alarms considered to be part of?
Objective 2 Page 17
Class 2
What types of circuits can conventional field devices be connected in?
Objective 4 Page 28
Either Class A or Class B
What is a disadvantage of a class b circuit in a trouble condition?
Objective 4 Page 29
All devices downstream of break are inactive.
What condition will a panel show if there is a short circuit in the initiating loop/detection circuit?
Objective 4 Page 29
Alarm condition.
What condition will occur in a fire alarm system if a short circuit occurs in a N.A.C./Signal Circuit?
Objective 4 Page 29
Trouble Condition.
What will cause a supervisory condition in a fire alarm system?
Objective 4 Page 27
Operation of a sprinkler gate valve.
What is the purpose of electrical supervision?
Objective 4 Page 28
To monitor all field wiring past the panel and monitor for trouble and alarm conditions.
What are magnetic reed switches housed in?
Objective 1 Page 3
A vacuum tube.
Makes it unaffected by arcingand moisture.
What condition will the panel register if an open path occurs in the detection or signal circuit?
Objective 4 Page 29
Trouble Condition.
