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| Carfire in Boemlafjordtunnel 18.12.2000 (2 cars) |
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| Test set-up: 150 meter FTLD "Flexible Thermocouple Linear Detector" was installed, from mark 5380m to mark 5260m. 120 meter length of the tunnel was covered by the FTLD, the remaining 30 meters was used for connection to the controller and as test-end. The FTLD was installed on the cable ladder in the roof, such as the test would be identical to a fixed installation. The cars were placed from mark 5350m to mark 5340m, the ventilation brought heat and smoke in direction of mark 5260. Eurotherm 2500 was used as controller, together with Eurotherm iTools software for logging purpose. The software was set to log every second. The controller had two alarm limits. One would activate if the temperature rised more than 3°C per minute (Rate of Change) and the second alarm was set to 25°C fixed. The ROC limit of 3°C was selected because this is the most common limit for traditional heat detectors. The fixed alarm of 25°C was selected based on the experience from the test performed in the RennFast tunnel. Eurotherm 2500 has also input/s for gas detectors, ex. measuring of CO, but this was not used during this test. Fire progress: From the cars were set on fire (ambient temp. 8,5 °C), it took only 2 minutes and 20 seconds before the ROC alarm limit was reached, and the temperature was 14,5°C at this time. Then after further 1 minute and 12 seconds the fixed alarm limit was reached. The maximum temperature was 30,5 °C after 5 minutes and 17 seconds, then the fire ventilation started and brought the temperature down. A third alarm , called deviation, could also have been used. Deviation is an alarm function that activates if the differential temperature between two neighbour zones(two neighbour FTLDs) exceeds a limit. It could have been set up to activate if the differential temperature exceeded 3 °C, and if so this system would be able to give alarm 1 minute and 44 seconds after the cars were set on fire. At this test one FTLD was used. Conclusion: The smoke-plug arrived at the tunnel outlet in Valevåg first 25 minutes after the fire started, even that the fire ventilation was activated more than 20 minutes of this period. In a real fire situation the smoke-plug would have arrived the outlet even later, if there was no one to call the "roadtraffic control room" and alarm them. The fire ventilation is started manually. FTLD can effectively detect a car fire, automatically alarm the "roadtraffic control room", activate the fire ventilation directly and close road barriers at both ends, to avoid other vehicles driving into a tunnel in fire. The system can also have gas detectors connected for measuring of CO concentrations. |
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| Haugesund Process Control as FTLD System for Tunnel Temperatur Varsling. Enkel sløyfe. | |||
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© Copyright 1999-2007 Xco International Incorporated. All rights reserved. CT²C, FTLD and Continuous Thermocouple are registered trademarks of Xco International Incorporated. World-wide patents pending... |
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