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Aircraft Cargo Aircraft Cargo CompartmentCompartment Fire Detection Fire Detection
David Blake
FAA William J. Hughes Technical Center
Atlantic City Airport, NJ. 08405
Phone: 609-485-4525
Email: [email protected]
Federal Aviation Regulation
Part 25.858 Cargo compartment fire detection systems.
If certification with cargo compartment fire detection provisions is requested, the following must be met for each cargo compartment with those provisions:
(a) The detection system must provide a visual indication to the flight crew within one minute after the start of a fire.
(b) The system must be capable of detecting a fire at a temperature significantly below that at which the structural integrity of the airplane is substantially decreased.
(c) There must be means to allow the crew to check in flight, the functioning of each fire detector circuit.
(d) The effectiveness of the detection system must be shown for all approved operating configurations and conditions.
FAA Technical Standard Order (TSO) C1c
Cargo Compartment Fire Detection Instruments
References a Society of Automotive Engineers (SAE), Aerospace Standard AS 8036
Type I: Carbon Monoxide, Alarm level 200 +/- 50 ppm.
Type II: Photoelectric, Alarm level 60-96% light transmission/foot.
Type IV: Ionization, Alarm level 60-96% light transmission/foot.
Environmental Exposure Tests: High and Low Temperature, Humidity, Altitude, and Vibration.
False Alarm Signals.
“No alarm shall occur from normal air velocities present at instrument location.”
“No alarm shall occur as a result of normal dust and haze present at instrument location.”
FAA Advisory Circular 25-9A
Smoke Detection, Penetration, and Evacuation Tests and Related Flight Manual Emergency Procedures.
“The smoke detection test is designed to demonstrate that the smoke detector installation will detect a smoldering fire producing a small amount of smoke.”
Tasks
• Define the fires that should be detected in one minute. (FAA)– Smoldering Fire (Low Heat/High Smoke), Flaming Fire (High Heat/Low smoke)
– Smoke and Gas Production
– Heat Release Rate
• Develop a computational fluid dynamics model to predict the transport of smoke, gases, and heat within a cargo compartment (Sandia National Laboratory)
• Evaluate fire and false alarm sources in existing detectors and provide algorithms for multiple sensor detectors. (National Institute of Standards and Technology)
Verified Smoke Events vs. Smoke Alarms
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Verified Smoke
Figure 5. Number of False Positive Alarms for Every Alarm Due to Verified Smoke Events
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75-79 80-84 85-89 90-94 95-99
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False Alarms
Nylon
Polyethylene
Acrylic
Polystyrene
PVC
PBT
Smoldering Fire Source
Gasoline
Burlap
Flaming Fire Source
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Time (seconds)
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/Fo
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Ceiling Smoke6 (910 ft3)
Ceiling Smoke7 (910 ft3)
Ceiling Smoke8 (910 ft3)
Desired Ceiling smoke (910 ft3)
Ceiling Smoke (2000 ft3)
FTIR Gas Analysis, Heat Release Rate (Oxygen Consumption)
INTENDED RESULTS
•Reduce the subjectivity involved in determining the appropriate amount of smoke for certification testing.
•Reduce the required ground and flight tests to determine optimal detector placement and critical fire location through the use of a transport model.
•Develop criteria to allow for certification of multiple sensor detectors to reduce the false alarm rate.
