SIMPLE AND RELIABLE FIRE DETECTION IN ROAD TUNNELS

Transcription

1 SIMPLE AND RELIABLE FIRE DETECTION IN ROAD TUNNELS Dr. Arnd Rogner Metaphysics SA 1

2 Contents Actual detection technologies (in Europe) Field experience in tunnel fire detection System integration 2

3 Road tunnel fire detection technologies (Europe) 3

4 Road tunnel fire detection technologies (Europe) Line type heat detectors (LTHD) Measuring heat emission from fire Visibility monitors / smoke detectors Measuring smoke density Video analysis Reacting on different parameters like stopped vehicles, smoke density, or open flames 4

5 Road tunnel fire detection technologies (Europe) Line type heat detectors (LTHD) Absolute temperature and/or rate-of-rise detection Temperature profile Loop installation with 2 control units for increased availability Semiconductor and fiber optic systems 5

6 LTHD Systems: Semiconductor sensor cable Description: Temperature sensor cable with individual sensors in a distance of 4 m to 10 m for road tunnel application Temperature measurement by semiconductor sensors using the band gap effect Comments: Threshold of each sensor editable Reaction in RABT test 30 to 60 sec No maintenance 6

7 LTHD systems: Fibre optic sensor cable Description: Fibre optic measurement system with laser (OTDR or OFDR or code correlation measurement) Comments: Different generations with different specifications on the market In certain solutions we have a dependence: spatial resolution temperature resolution length of the system - detection speed 7

8 Visibility Measurement / Smoke Detection Visibility monitors or special smoke detectors Description: Optical scattered light or transmission measurement Installation distance m Comments: Low fault alarm rate (scattered light) Heating system to avoid interference by fog 8

9 CCTV Based Information System Description: Pictures of CCTV cameras in the tunnel are analyzed Comments: Response speed: high (smoke and fire) Alternative: detect stopped vehicle Non-negligible false alarm rate Manual alarm verification required Useful for early fire detection in tunnels with high risk potential 9

10 Fire detection in road tunnels - guidelines LTHD specified in most countries for tunnel fire detection E.g. DE, CH, AT, ES, CN, KR, TW, SP, BR, CO, Several countries request smoke detection in addition E.g. DE, CH, SK In addition smoke detection is used in more countries, even if it is not yet required in a directive Some countries just request fire detection, but do not specify the technology Can be LTHD, smoke, video-based detection Some countries use no automatic fire detection 10

11 Field experience 11

12 We have different kinds of fire Fires by accident Tauern 1999 Gotthard 2001 Gleinalm 2001 Viamala 2006 Fires by defects Gotthard Ø 4 per year - Overheating - Turbocharger damage - Tire fire - Blocked brakes 12

13 Smoke is faster than heat Most fires start with smoke, before we get open flames Tauern and Gotthard fires would have been detected earlier by smoke detection Pool test fires in this sense are not mirroring the reality 13

14 Smoke is faster than heat Test # Fire size Wind velocity Detection time smoke detectors Detection time LTHD MW 1.6 M/S 2:13 2: MW 1.6 M/S 1:29 1: MW 1.6 M/S 1:34 0: MW 1.15 M/S 1:25 1: MW 1.15 M/S 1:10 0: MW 1.15 M/S 0:57 0:25 7 CAR FIRE 1.55 M/S 0:52 2: MW POOL 1.8 M/S 1:23 0:25 Results of Runehamar tests 2007 From: ARALT, T.T., NILSEN, A.R. (2009): Automatic Fire Detection in Road Traffic Tunnels; Tunneling and Underground Space Technology, Vol. 24/1, pp

15 Smoke is faster than heat In case of a real car fire, smoke detectors can be (significantly) faster than thermal detection Pool fires give nice reproducible test conditions for approval and test of system, but they are not mirroring the reality of a car fire In case of fires after accidents with fuel spills and instantaneous developing open fires, the thermal detection will be faster 15

16 Moving vehicles in fire What happens, if a burning vehicle continues to drive? Truck drivers are even trained to do so How will our detection system react? 16

17 Time Moving vehicles in fire Location Turbocharger damage in Gotthard tunnel From: GRÄSSLIN, URS (2010): Erfahrungsbericht Rauchdetektion aus dem Gotthardstrassentunnel; Proceedings of 9th Symposium Sicherheit im Strassentunnel durch Einsatz moderner Messtechnik, Sigrist-Photometer AG, Geroldswil 17

18 Moving vehicles in fire Localization by smoke is more difficult, as smoke is spreading over a certain distance More complex algorithms are required to control the ventilation CCTV cameras might be blind due to high smoke density Temperature detection is the only way to identify the position of the burning vehicle Temperature Smoke 18

19 Important properties of thermal detection 19

20 Importance of fast detection Avoiding fatalities in tunnel fires is mainly driven by self rescue Simulations show that the number of fatalities is proportional to the detection time of the fire (or in fact to the time informing the users and their reaction) If we reduce the detection time, we also can reduce the number of fatalities 20

21 Fast detection approval test fires in Germany Tunnel Test 1 Test 2 Test 3 Test 4 Felderhalde Kohlberg Nord Kohlberg Süd 37 s 5 MW, 5m/s 31 s 5 MW, 6m/s 50 s 5 MW, 6m/s s 2.5 MW, 3m/s 52 s 2.5 MW, 3m/s Stauffer - 28 s 5 MW, 6m/s Schwetzingen - 26 s 5 MW, 6m/s Ditschhardt 36 s 5 MW, 6m/s 5 MW Brand according to RABT 70 s 2.5 MW, 2m/s ca. 60 s 5 MW, >6m/s 44 s 5 MW, 6 m/s 52 s 2.5 MW, 4m/s - 58 s 2.5 MW, 3m/s 50 s 1.25 MW, 2m/s - 26 s 5 MW, 6m/s 21

22 Fast detection test fire Ditschhardttunnel 22

23 The precise localisation is important After detection the smoke valves and/or supression systems are triggered The zone length typically is 100 m for smoke valves and 25 m for supression systems The adressing of the correct zones is crucial for the lifes of the users Influence of air speed Detection of radiation heat Influence of drift for FO systems Needs regular recalibration 23

24 Precise detection test fire Ditschhardttunnel Temperature profile MHD

25 Precise localisation of the fire 25

26 Alarm criteria for thermal detection Absolute temperature threshold at 60 C Backup Gradient threshold at 3 C / 20 sec (9 C / minute) Standard reaction type in real fires and tests Dual-detector-dependence helps to reduce false alarms - 1 sensor has to have 2 alarms in sequence - 2 sensors give alarm at the same time Under difficult conditions (e.g. sunlight at entrance), the gradient condition can be increased up to 5 C / 20 sec 26

27 Systemintegration 27

28 Smoke detection Temperaturevalues Alarms Alarms System integration fire detection: Example D / A Tunnel monitoring and control system Alarm activities: - Ventilation - Escape Lights - Fire Brigade - Closure -.. GW FAP Redundance Building Fire Detection Manual Callpoints Tunnel Fire extinguisher contacts etc. FAP Relays PU PU LTHD 28

29 FAP Building, etc. Smoke detection Alarms, Temperaturevalues System integration fire detection: Example CH Tunnel monitoring and control system Alarm activities: - Ventilation - Escape Lights - Fire Brigade - Closure -.. GW Redundance GW PU PU LTHD 29

30 System integration fire detection Challenge Different system architecture in different countries (projects) Partly using different interfaces / protocols (Modbus TCP/IP, Profibus, IEC , ) This requires different integration concepts and components The cost for the integration part is increasing Redundancy for all signal / information transmission Standardization would make sense 30

31 Conclusion Thermal detection is mandatory. It is the most reliable method and the only one to localize a fire in case of a smoke-loaded tunnel The thermal detection can localize a fire within 10 m (or even less) For the selection of a linear heat detector, reaction time, precision of localization, and maintenance effort should be regarded Smoke detection is a recommended addendum, as small car fires are seen significantly faster. Users can win several minutes to escape A standardized integration concept could reduce cost 31