Briefly describe the components of a thermal switch fire detection system
Temperature sensitive switches that complete a circuit at a specific temperature and trigger a warning
Are thermal switches wired in series or in parallel with each other?
How are the detector units in a double loop Fenwal system wired?
In parallel between two complete loops of wiring
In what way is a thermocouple fire warning system different from a thermal switch system?
Thermocouple systems measure rate of temp change,
thermal switches respond to a specific temp
Briefly describe the components of a Kidde continuous loop fire detection system
An Inconel tube containing one or more wires embedded in a ceramic core whose resistance changes with temperature
Describe the components and operation of a Lindberg fire detection system
A stainless steel tube contains an inert gas and a discrete material that absorbs some of the gas. When the tube heats up, gas is released raising pressure inside the tube activating a pressure switch
How does a photoelectric smoke detector generate a warning of possible fire?
Smoke particles refract light in the unit, causing the photoelectric cell to produce electricity and cause an alarm signal
How can the operation of a photoelectric smoke detector be tested?
Actuating a test switch
Name two types of smoke detection systems used in aircraft
Photoelectric and Ionization
What are the usual locations where a carbon monoxide detector would be installed?
Cockpit or cabin
How does a CO detector indicate?
Tan spot turns dark
What are the possible effects of kinks and sharp bends in the sensing element of a fire warning system?
False fire warnings caused by short circuits
How is a Freon container checked for proper pressure?
A chart must be used to determine the max and min gauge pressure readings based on ambient temperature
Name the two basic types of fire extinguishing systems
The conventional system and
Name the agent most commonly used by conventional fire extinguishing systems
Carbon Dioxide CO2
Name the agent most commonly used by high-rate discharge fire systems
How are Halon bottles protected from excessively high temperatures and how can you tell that this has occured?
A thermal fuse will release the agent if the bottle temp exceeds a certain limit- this blows out a red indicator disk
What condition is indicated if the yellow disk is missing in a fire ext. system?
Describe the mechanism by which a Halon (aka Freon) bottle is discharged?
An electrical signal fires an explosive squib, which ruptures a frangible disk
How is the service life of a discharge cartridge calculated?
From the date stamped on the cartridge by the manufacturer