A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
The paper aims at a detailed analysis of the current know-how in the construction of tunnel cabling systems and shows the impact of fire and heat and the respective measures to be taken. Therefore the results of the test projects EUREKA Firetun and MEMORIAL are scrutinized and evaluated in view of the todays boundary conditions in typical cross sections. It will clearly be shown how the heat distribution is dependant on the cross section and the ventilation system. Further it will be shown how concrete will protect cables from heat and damage even if the coverage is low and how far open mounted installation channels are endangered. For typical cabling systems it shall be outlined which requirements and specifications regarding fire and heat resistance are reasonable and required. A short discussion of the applicable norms and standards shall provide further information and decision guidance. It shall be clarified that high safety standards re-isolation and fire resistance are not generally required. The temperatures indicated in the standards always describe the values maximally arising during a fire event; however, these values have to be expected only within the upper tunnel area. At the lower level the temperatures are significantly lower. Due to safety considerations, the general demand for system circuit integrity cannot be justified for cable systems in accordance with DIN 4101-12, since the risk reduction is only marginal in many cases. However, each project must separately be regarded due to the object-specific conditions.
The paper aims at a detailed analysis of the current know-how in the construction of tunnel cabling systems and shows the impact of fire and heat and the respective measures to be taken. Therefore the results of the test projects EUREKA Firetun and MEMORIAL are scrutinized and evaluated in view of the todays boundary conditions in typical cross sections. It will clearly be shown how the heat distribution is dependant on the cross section and the ventilation system. Further it will be shown how concrete will protect cables from heat and damage even if the coverage is low and how far open mounted installation channels are endangered. For typical cabling systems it shall be outlined which requirements and specifications regarding fire and heat resistance are reasonable and required. A short discussion of the applicable norms and standards shall provide further information and decision guidance. It shall be clarified that high safety standards re-isolation and fire resistance are not generally required. The temperatures indicated in the standards always describe the values maximally arising during a fire event; however, these values have to be expected only within the upper tunnel area. At the lower level the temperatures are significantly lower. Due to safety considerations, the general demand for system circuit integrity cannot be justified for cable systems in accordance with DIN 4101-12, since the risk reduction is only marginal in many cases. However, each project must separately be regarded due to the object-specific conditions.
Safe cabling systems in tunnels under fire
Welte, Urs (author)
2006
6 Seiten, 10 Bilder
Conference paper
English
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