15.20 – Fire Protection Flashcards
A fire protection system consists of what two systems? (3)
- Detector circuit
- Alarm circuit
- Test circuit
What is a fire bottle containing Halon made from?
Steel
Why are CO2 bottles charged with Nitrogen?
The nitrogen charge provides sufficient pressure for complete discharge of the agent.
What precautions must be taken when replacing Fire bottle cartridges/Squibs?
Isolate the cartridge electrical circuit by pulling the relevant circuit breakers and collaring them, also disconnect the cartridge electrical connectors and shunt the cartridge electrical pins with a protective shunt provided by the manufacturer.
Use a shunt plug or shorting clip to prevent discharge of the fire bottle.
What happens when the Fire Handle is pulled?
- Silencing of aural/vocal warning,
- generator field circuit to open,
- Engine fuel fire shut-off valve to close,
- Hydraulic fire shut-off valve to close,
- Pneumatic crossfeed valve to close,
- Agent discharge switch to arm
(Rotating pulled handle in either direction causes the respective agent to discharge)
What is the indication given in the event of a fire?
A bell and a Engine Fire warning light
What systems are cutoff when the fire handle is pulled?
- Aural Warning cancellation
- Electrical GEN deactivation
- Engine fuel fire shut-off valve to close
- Hydraulic fire shut-off valve to close
- Pneumatic crossfeed valve to close
- FADEC elec power cut off
- Pack flow control valve closure
- Agent discharge switch to arm
- Rotating pulled handle in either direction causes the respective agent to discharge
Which types of fire detectors are generally used on engines? (4)
- Thermal switch Type
- Thermocouple Type
- Continuous-Loop Detector Systems (Fenwal & Kiddie)
- Pressure-Type Sensor Responder Types
What types of detectors are Fenwal?
Continuous-Loop Detector systems
'’The single conductor (Fenwal) element has a center conductor supported in a thin-wall inconnel tube by ceramic beads. An electrical connection is made to the conductor, and the outside tube is grounded to the airframe.
The space between the beads is filled with a eutectic (low melting point) salt whose resistance drops drastically when it melts.
When any portion of the tube gets hot enough to melt the salt, the resistance between the center condcutor and the otuside tube drops, and signal current flows to initiate a fire warning
Describe a Walter Kidde fire detector?
Continuous Loop fire detector with two conducting cores
Describe a Systron Donner fire detector, what type of gas is contained in it?
Pneumatic Fire Loop
Absorbs gas when it is cold but releases gas when it is hot, increasing pressure and puching close alarm switch
The tube is filled with Helium gas
