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Fire Protection
Consists of the fire and smoke detection subsystem, and the fire extinguishing subsystem. Protection is provided for the engines and pylons, the APU, the cargo compartments, and the lavatories and lavatory waste bins.
Bottles carried onboard are 2.5lbs of blended HALON 1211/1301 with low toxicity characteristics.
Fire and smoke detection
Engines
Fire detectors are connected to MAU 1 (DC ESS Bus 1) and MAU 3 (DC ESS Bus 2) to generate indications in the cockpit. Indications are the master warning light, fire bell, a red light in the fire handle, EICAS messages, and FIRE annunciator on the ITT gauge. The fire detectors in the engine are pneumatic fire detectors in two loops, connected to the MAU. With both loops operative, both must detect a fire, otherwise the one operative loop detecting fire is sufficient.
APU
Uses 2 pneumatic fire detectors, which are connected to MAU 1 and 3 and supply information to the EICAS and CMC. Similar in operation to the engine detection system. When airborne, if the EMER STOP button has not been pressed after 60s, the MAU commands the APU fire extinguisher button to illuminate. On the ground, the APU shuts down automatically after 10s.
Cargo compartment
Uses photo-electric fan type sensors installed in recessed trays in the ceiling of the compartments. Signals are routed to the flight deck via the MAUs. When 1 sensor in the forward cargo compartment senses fire, the optional air circulation fan stops, and the optional cargo compartment shutoff valve closes. The cockpit is not initially notified. If another detector goes into alarm within 45s, it is treated as a fire, otherwise it is treated as a detector fault.
| Aircraft Type | Forward Compartment | Aft Compartment |
| 170LR | 3 | 2 |
| 190AR | 4 | 3 (fire must be detected by 2) |
Landing gear bay
An optional system that provides main gear fire detection through a dual loop pneumatic sensor installed in each main wheel well.
Lavatories
Consists of smoke dectectors on the ceiling. Indications of a fire are CAS messages, smoke detector chime, red light on the smoke detector, and amber light on the attendant lights.
Fire extinguishing
Engines
2 fire extinguisher bottles, A and B, are installed. Extinguishing agent is taken from the bottles to the engines via aluminum / stainless steel distribution pipes. Each bottle can be fired into either engine.
APU
There is 1 bottle available for the APU.
Cargo compartment
2 bottles are installed in the centre e-bay. The high rate discharge (HRD) bottle has about 5.91kg of HALON 1301, while the low rate discharge (LRD) bottle has about 9.98kg of HALON 1301. They can be fired into either compartment. The HRD bottle is meant to extinguish the fire, while the LRD bottle prevents reignition and the agent remains in the compartment for 60 minutes. The LRD fires 1 minute after the HRD has been fired inflight, or can be fired manually. On the ground the cargo fire extinguishing button must be manually pushed to fire the LRD bottle. If there is no accompanying fire warning, the button must be pressed twice to arm and fire the HRD bottle, rather than once with a fire warning.
Lavatories
Fire extinguishing bottles in the waste disposal automatically discharge when the tip melts at 78°C. Discharge indication is on the pressure gauge on the bottle.
Control panel
| TEST* | illuminates fire handles, master warning lights, EICAS messages (5), aural alarm, fire extinguishing buttons, APU emergency stop button, FIRE annunciator |
| APU fire extinguishing button | if the APU emergency stop button has not been pressed, the fuel shutoff valve is colosed and the APU shut down |
| cargo fire extinguishing button | if pushed once, |
*With the APU running, the test should not take more than 10s, otherwise the APU will shut down.
EICAS messages
ENG 1/2 FIRE DET FAIL - both fire detection loops have failed
CRG FWD VENT FAIL - the cargo vent fan will not stop when tested
CRG FWD/AFT SMOKE - fire indication stays on as long as the fire situation exists