Alarm Systems and Smoke Alarms Flashcards
There are two categories of intrusion sensing devices, what are these?
- Perimeter devices
- Interior devices.
What are three common perimeter devices?
- Magnetic reed switches
- Roller ball contacts
- Glass break detectors.
When installing a magnetic reed switch, what must be ensured?
Proper positioning of the magnet to avoid nuissance tripping.
What is the prime disadvantage of roller ball contacts when compared to magnetic reed switches?
Cost to produce is higher, since roller ball contacts are a mechanical device.
Could very small conductors be run with window screening to alarm against ripping or cuts of the screen?
Yes, this makes an open window much more secure.
What triggers a dual technology glass break detector?
What must be ensured when installing one?
Acoustic sound pattern of glass breaking and acoustic shock waves due to a rapid pressure change.
The device must be mounted in line of sight to minimize acoustic muffling.
What are two common internal device technologies used in security systems?
- Passive infrared detectors
- Microwave motion detectors.
When installing wireless alarm devices, what must be ensured?
A path unobstructed by metal ducting, to maintain signal fidelity.
Typically, where should one install signal devices for a security system?
In a relatively inaccessible place like a cold air return or attic space; this amplifies the acoustic quality and minimizes tampering.
The CPU of a typical alarm system operates on a “_____” voltage and has a “_____”.
- Low AC.
- Battery backup.
Zone loops can be programmed in three ways; what are these?
- Normally open loop
- Normally closed loop
- Monitored loop.
What is a monitored loop?
One which uses an end of line resistor to monitor a small current through the circuit.
What are sirens typically rated in?
Wattage and decibel output.
What is a signal device?
A device which produces an audible or visible signal to alert people of a problem.
What size aluminum wire should be used when wiring an alarm system?
Only copper may be used in a class 2 circuit.
There are two common technologies for smoke detectors, what are these?
- Ionization or product of combustion
- Photoelectric or light obscuration or projected beam
Which smoke alarm would be better at detecting a large flaming fire with little smoke?
Ionization type are faster at detecting these types of fire.
In a single dwelling where are smoke alarms installed?
- On every storey
- Every sleeping room
- In hallways between sleeping rooms.
Should all smoke alarms be interconnected?
Generally yes.
When adding new alarms they must all be interconnected with each other but not necessarily with the old system.
What are the four conditions in which a fire alarm system could display?
- Normal
- Trouble
- Alarm
- Supervisory.
Which 3 components must a basic fire alarm system contain?
- A control unit for logic processing,
- A manual pull station
- An audible signal device.
What is supervisory current used for in an alarm system?
To continuously monitor the interconnection of devices and anunciate any faults in the wiring.
What is a class B fire alarm circuit?
One which uses an end of line resistor.
What is a class A alarm circuit?
One which terminates back at the panel and creates two closed loops.
Could two or more wires be connected to any one terminal on fire alarm equipment?
No, only one wire per terminal, every time.
What technology’s basic principles were a large part of the development of motion detectors?
Radar
