# Presentation: 690918

## Fourth Triennial International Fire and Cabin Safety Research Conference Test Methods and Apparatus for a Video-based System designed for Cargo Fire Verification 

- Ingolf Willms, Wolfgang Krüll
- Department of           Communication Systems
- University Duisburg-Essen

- Jeff Shirer
- Goodrich Corporation
- Vergennes, Vermont, U.S.A.

## 1  Motivation 

- 1  Motivation
- 2  Testing aspects of video-based systems
- 3  Fire and smoke tests
- 4  Dust tests
- 5  Summary and outlook

## 1  Motivation for a video-based Cargo Fire Verification System 

**1  Motivation for a video-based Cargo Fire Verification System**** **

- In case of smoke alarm: Crew must activate the extinguishing system and land at the nearest suitable airport
- Pilot has no capability to verify if the alarm is real or false
- 	False alarms of smoke detectors in cargo bays during long range flights of passenger airplanes cause various problems:
- Diversion to a small airport may cause significant danger
- Consequences: High costs due to flight diversions, landing costs, possible loss of the cargo load

## 1  Motivation for a video-based Cargo Fire Verification System 

**1  Motivation for a video-based Cargo Fire Verification System **

- Possible reasons for false alarms of traditional smoke detectors in cargo compartments:
- Mist, dust and oil particles
- Additional problems are environmental conditions
- 	(e.g. temperature variation, air pressure variation)
- Objectives of the Cargo Fire Verification System:
- To provide the aircrew with images of the conditions in the cargo bay
- To detect fire earlier than conventional smoke detectors
- Thus to verify it or not
- Thus to greatly reduce false alarms

## not easily accessible during flight

- a difficult area to view with video cameras

- The gap between the cargo and cargo bay ceiling can be only 4.3 cm

- Cargo compartments are

**1  ****Motivation for a video-based Cargo Fire Verification System**** **

## Example of camera and illumination placement in a cargo bay of an AIRBUS A340-500:  	FWD	(in front of the aircraft)

- Example of camera and illumination placement in a cargo bay of an AIRBUS A340-500:**  ****	**FWD	(in front of the aircraft)
- 	AFT, BULK 	(behind the wing boxes)

**For reference:**	The size of an A340-500 AFT compartment is
- 		10.4 m long   *	4.2 m wide   *	1.7 m high

**1  Motivation for a video-based Cargo Fire Verification System**** **

## 1  Motivation - Qualification Testing of traditional detection systems

**1  Motivation - Qualification Testing of traditional detection systems**
- Existing testing guidelines & standards for smoke detection systems were formulated for traditional sensor technologies (e.g. optical-based)
- EN-54 tests use different types of smoke sources at the centre of the floor in a fire lab
- Essential measurements: Reference smoke density measurements at the location of the detector & detector alarm time
- The geometry and contents of the test chamber are not critical to smoke detectors if the smoke density increases within EN-54 specs

## Motivation – Requirements for the test of video fire detection systems (CFVS)

-  Similar procedures as in EN54 are reasonable (as far as possible)
-  Comparison with EN54 qualified conventional detectors are needed
-  Suitable stimulation of video sensors in field of view required
-  No down scaling possibilities concerning room size
-  No tests in a smoke duct are possible
-  Increasing stimulus over time (as in EN54)
-  Consequences:
-   New testing details needed
-   Modifications of EN54 are needed

## 2  Testing aspects of video-based systems – Some CFVS images  

- Four views with different illumination, same geometric configuration

**2  Testing aspects of video-based systems – Some CFVS images****  **

## 2  Testing aspects of video-based systems

**2  Testing aspects of video-based systems**
- 	For a video-based detection system, scene geometry and image contents are critical
- The scene should closely represent the actual application
- Usage of 1:1 scale – no test chamber
- The fire test room should resemble an actual cargo bay
- This includes cargo obstructions in cameras field of view
- Tests should retain the repeatability aspects of the EN-54 tests

## 2  Testing aspects - Possible candidates for testing of the CFVS

**2  Testing aspects - Possible candidates for testing of the CFVS**
- Special testing aircraft
- Many disadvantages:
-  High costs, limited test times
-  Restricted test options
-   (no open fires are permitted)
- A reconstruction of a cargo compartment
- Main drawbacks (Trauen mock-up):
-  Limited control of environm. conditions
-  High construction effort
-  Large required space
-  Hard to change
-  No comparative EN-54 tests are possible

## 2  Testing aspects - Possible candidates for testing of the CFVS

**2  Testing aspects - Possible candidates for testing of the CFVS**
- A modified EN-54 test room (Duisburg fire lab)
- EN-54 like test cell
- Option of changing the test cell height within minutes (2,90 ...> 4 m)

- Advantages of the fire lab of Duisburg University:

- Controlled environmental conditions
- EN 54 measurement conditions
- A wide range of measurement possibilities
- Good probability for “repeatable” tests

## Fire and smoke tests - Performed in the A340-500 cargo bay

**Fire and smoke tests - ****Performed ****in the A340-500 cargo bay**
**       ****mock-up in Trauen and in the Duisburg fire lab**

- In the Duisburg Fire Detection Lab tests were performed in three major types of scenarios:
- Standard  EN-54 test fires
- Modified test fires _without test cell modifications_,
- 	but with camera obstructions by containers
- Modified test fires _with test cell modifications_
- 	(for Forward, Aft, and Bulk compartment configurations,
- 	including camera obstructions by containers)
- 	Test cell modifications for closely resembling an actual cargo compartment
-     Fire material reduction to account for the reduced test cell volume

## 3  Fire and smoke tests – Performed in Duisburg and in Trauen

**3  Fire and smoke tests – Performed in Duisburg and in Trauen**

- Modified EN-54 	A340-500 cargo bay
- test cell in Duisburg	mock-up in Trauen
- (without side walls)
- Volume: 293 m3 	Volume: 103 m3
- 10.5 m * 9.0 m * 3.1 m	15.0 m * 4.2 m * 1.71 m

## 3

- Standard EN-54 test fire material was reduced to account for
- 	the reduced test cell volume
- Room geometries of both test cells are completely different

**3  Fire and smoke tests – Performed in Duisburg and Trauen**

**3**

**Scaling**
**factor**

- Results are comparable by using a simple scaling factor
- 	to approximate the results from Trauen

**MIREX values**

## Test cell modifications:

- Aluminium side wall plates were hung from the ceiling
- 	to reduce the room width
- Fire and non-fire sources
- 	were placed on a platform
- The distance between
- 	the source and the fire
- 	room ceiling then was 1.7 m

**3  Fire and smoke tests - Test cell modifications**

## 3  Fire and smoke tests - Test cell modifications

**3  Fire and smoke tests - Test cell modifications**

- Side walls were covered with DuPont Tedlar PVF Film  (as in real cargo bay)  for improved realism
- Single 1 m2 sheet metal plates (also covered with the cargo bay lining material) was mounted on the ceiling for further improved realism

## 3

**3**

**1.5**

**Scaling**
**factor**

**without side walls**

**with side walls**

**with side walls**

**smoke density via the MIREX**

## CFVS performance compared to conventional A340 detectors

**CFVS performance compared to conventional A340 detectors**

- The CFVS was designed as a verification system, intended to confirm or unconfirm alarms issued by the primary system.
- The CFVS has to detect fires earlier than conventional smoke detectors and to confirm the primary system’s alarm.

## 4  Dust tests

**4  Dust tests**

- Many false alarms in cargo bays are caused by fog and dust
- Dust lifted from dirty containers   or
- Perhaps produced by cargo content such as animals
- Dust is known to cause problems with optical smoke detectors -
- 	and not only in cargo bays.
- Depending on the dust type and the dust production
- 	it may look similar to smoke on video.
- Discrimination of dust and smoke in video-based systems thus is a challenge in its own.
- Density of dust was chosen such that it caused the conventional smoke detectors to alarm.

## 4  Dust tests - Set-up for Bulk bay dust tests

**4  Dust tests - Set-up for Bulk bay dust tests**

## 4 Dust tests - Smoke detector alarm times

**4 Dust tests - Smoke detector alarm times**

- Different cargo compartment types (Aft bay / Bulk bay)
- Different dust types (dust A1 / dust A2)

- 10

- 20

- 30

- 40

- 50

- 60

- 70

- 0

- 1

- 2

- 3

- 4

- 5

- 6

- 7

- Samples

- Time after dust generation start [sec.]

- Aft Bay - A1

- Aft Bay - A2

- Bulk Bay - A1

- Bulk Bay - A2

- Average

## 4 Dust tests - Particle counter values in the experiments

**4 Dust tests - Particle counter values in the experiments**

- 2 minutes of dust generation
- Dust tests were considered valid
- 	if the max. particle counter value was greater than 9000

## Dust tests - CFVS performance compared to conventional     A340 detectors

**Dust tests - CFVS performance compared to conventional     A340 detectors**

- The success criterion for the CFVS was to diagnose a non-fire case and to unconfirm the primary system’s alarm
- Thus to reduce false alarms

## 4  Conclusions and outlook

**4  Conclusions and outlook**

- The existing testing guidelines and standards for qualification of current smoke detection systems were formulated mainly to address the case of traditional detection technologies.
- So it was necessary to develop
- a suite of fire sensitivity tests,
- non-fire tests with dust   and
- EN-54 test room modifications
- 		applicable to video-based fire detection systems.
- Modified tests with room modifications in the Duisburg fire lab show good match with tests performed in a cargo mock-up
- 	for Forward, Aft and Bulk bay configuration.

## 5 Conclusions and outlook

**5 Conclusions and outlook**

- Recordings of
- point smoke detectors,
- video sensors, and
- reference measurement devices
- 	were obtained in exhaustive test series in the Duisburg Fire Lab.
- Data were then used
- in the course of the algorithm development of the CFVS
-     by Goodrich Corporation, and
- for defining the performance criteria.

## 5 Conclusions and outlook

**5 Conclusions and outlook**

- Possible improvements for future CFVS tests:
-   Improvements in dust generation (reduction of charged particles)
-   Use of additional dust types
-   Tests with forced ventilation