Aircraft Cargo

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International Aircraft Systems Fire Protection
Working Group Atlantic City, NJ October 30-31,
2002
Aircraft Cargo Compartment Fire Detection
David Blake FAA Technical Center Atlantic City
Airport, NJ. 08405 Phone [phone] email
dave.blake_at_faa.gov
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Cargo Compartment Fire Detection Project
Objective

• - Standardize the fire(s) that should be detected
  (smoke, gas, heat output)
• - Provide guidelines for the certification of
  newer technology detectors (multi sensor or other
  nuisance alarm rejection techniques) to reduce
  the false alarm rate (1001)

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• 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
• The detection system must provide a visual
  indication to the flight crew within one minute
  after the start of a fire.
• 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.
• There must be means to allow the crew to check in
  flight, the functioning of each fire detector
  circuit.
• The effectiveness of the detection system must be
  shown for all approved operating configurations
  and conditions.

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FAA Technical Standard Order (TSO) C1c
7/10/87 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 III Visual, Alarm
level 70 /- 10 light transmission/foot. Type
IV. Ionization, Alarm level 60-96 light
transmission/foot.
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FAA Advisory Circular 25-9A Smoke Detection,
Penetration, and Evacuation Tests and Related
Flight Manual Emergency Procedures. Section
10.a.(2) A smoldering fire producing a small
amount of smoke in conjunction with the
applicable detection time has been selected as a
fire or failure condition that could be detected
early enough to ensure that the fire and smoke
procedures would be effective. Subjective
judgment, considering the failure , size of
compartment, materials contained in the
compartment, and the containment methods and
procedures, is needed to asses the significance
of a small amount of smoke.
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Target Smoke Level for Certification with
Existing Regulations
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False Alarm Issue
Source FAA Service Difficulty Reports, FAA
Accident/Incident database, NTSB reports.
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The NTSB has issued numerous safety
recommendations to the FAA based on a study
conducted on aircraft emergency evacuations. One
of the recommendations (A-00-91) is as
follows Document the extent of false
indications for cargo smoke detectors on all
airplanes and improve the reliability of the
detectors. The FAA Administrator responded to
the above recommendation in a letter dated
11/8/00. An excerpt from this letter is the
FAA is sponsoring a program to produce a standard
means of testing detectors to demonstrate
compliance with regulatory response requirements
and to develop reliable aircraft smoke and fire
detection systems that reduce the cargo
compartment false alarm rate. The WJHTC tests
will quantify typical gaseous compounds and
particulate resulting from cargo fires that can
be detected. These data can then be used to
standardize the procedures used to certify
multiple sensor cargo fire detection systems. The
FAA has been working with the WJHTC to ensure
that the information obtained from the testing
will lead to the development of appropriate
guidance and certification criteria.
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Starting point was the same quantity of smoke
previously used in certification tests in small,
narrow body cargo compartments.
707 Forward Compartment. 910 cubic feet
Rosco 1600. 10.5 ml/min.
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• Fire Source Criteria
• Good repeatability.
• Immediate plume of smoke and gases.
• Ability to generate all the products of
  combustion from actual luggage fires.
• Ability to run the fire source in a cone
  calorimeter hood to accurately measure the heat
  release rate, mass loss rate and generation rate
  of the products of combustion.
• Ability to remotely activate the fire source in
  an unoccupied compartment.

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Nylon Polyethylene Polyurethane Polystyrene PVC PB
T
Standardized Fire Source
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Smoldering Fire (Pyrolysis)
Spark Igniters, 2 ml heptane
Flaming Fire
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SMOLDERING RESIN BLOCK FLAMING RESIN BLOCK ROSCO
SMOKE GENERATOR
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707 Cargo Compartment
Ceiling Smoke Meters
Resin Block/Rosco Location
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Smoke generated for 60 seconds. Smoke source
stopped and a mixing fan was turned on for 4
additional minutes. The purpose of the mixing fan
was to allow the measurement of the total
quantity of smoke produced by eliminating
buoyancy effects.
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Smoldering Resin Alarm Times (Seconds) Detector
A 69 Detector B 66 Detector C 33 Detector D
36 Detector E 30 Detector F 36
Resin Block
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Resin Block
Smoldering Resin Alarm Times (Seconds) Detector
A 101 Detector B 69 Detector C 64 Detector D
85 Detector E No alarm Detector F 119
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Flaming Resin Alarm Times (Seconds) Detector A
56 Detector B 150 Detector C 39 Detector D
45 Detector E 32 Detector F 36
Resin Block
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Resin Block
Flaming Resin Alarm Times (Seconds) Detector A
70 Detector B 61 Detector C 52 Detector D
65 Detector E 81 Detector F 100
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Cone Calorimeter with FTIR gas analysis
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Cone calorimeter/FTIR
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Cone calorimeter/FTIR
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Cone calorimeter/FTIR
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Cone calorimeter/FTIR
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Cone calorimeter/FTIR
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Cone calorimeter/FTIR
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Smoldering fire source produces similar light
obscuration values as previously used smoke
sources for certification tests. It does not
produce any other measurable fire signatures that
could be used to discriminate between actual
fires and nuisance alarm sources.
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Volume 3500 cubic feet. Ventilation 850 CFM
DC-10 Below Floor Cargo Compartment
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Detector Alarm Time A
140 B 112 C
No Detection D No
Detection Alarm time is the average of 2 tests.
Compartment volume 3500 cubic
feet Ventilation850 CFM
Flaming Resin
Resin Block
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Detector Alarm Time A
107 B 056 C
No Detection D No
Detection Alarm time is the average of 2 tests.
Compartment volume 3500 cubic
feet Ventilation850 CFM
Flaming Resin
Resin Block
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Flaming Resin Block
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Signatures of Various Fire Sources in 707 Lower
Cargo Compartment.
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AC 25-9A specifies a smoldering fire producing a
small amount of smoke as the fire that should be
detected within one minute. The origin of that
statement was the desire to detect a fire before
it could grow to a size that was uncontrollable.
Not all fires transition through a small
smoldering state. Ignition of flammable fluids
goes directly into a flaming fire mode and may
produce little smoke initially. This type of fire
is more threatening to an airplane and would not
be detected quickly with detectors that only
respond to particulates.
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Cargo Liner Burnthrough Test Requirement. Minimum
Flame Temperature 1600 F. Minimum Heat Flux
7.5 BTU/ft2-sec. Test Duration 5
minutes Approximate Heat Release Rate 50
KW Flaming Resin Heat Release Rate 1 KW
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Halon Replacement Minimum Performance
Standards 2 X 2 Pan Fire with 0.5 gallons Jet
A Must be Extinguished/Suppressed within 30
Seconds. Approximate Heat Release Rate 200
KW Flaming Resin Heat Release Rate 1 KW
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• Project Status
• Flaming resin meets criteria for repeatability,
  generation of other fire signatures, remote
  activation and immediate plume.
• Smoldering resin does not meet all criteria. True
  smoldering sources exist but also do not meet all
  criteria.
• Flaming resin produces appropriate smoke and
  gases to be detected within one minute in small
  narrow body below floor compartments.
• Flaming resin does not produce sufficient smoke
  and gases to be detected within one minute in
  large ventilated compartments.

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• Recommended Direction
• Use the flaming resin block as the standard fire
  for detection.
• Develop simulants for the smoke, heat and gases
  produced by the flaming resin block.
• Scale appropriate detection time limits based on
  cargo compartment volume and ventilation rates.