Some standard design procedures used in Norwegian tunnel fires are presented. The main points are suggestion of specific standard vehicle fires, introduction added tunnel length to account for fire gas expansion flow losses and introduction of a fixed buoyancy force when downgrade blowing of fire gases. Tunnel fires are often described by maximum size. However, time to reach maximum size and fire duration are of no less importance. The fire load and duration are often more critical than the effect with respect to survival or escape. Furthermore, the fire does not develop instantaneously. 3 to 5 minutes after fire start, the fire size is moderate, even when dealing with big fire sizes. This period is important for escape. The fires are categorized into car, bus/truck, trailer, passenger train or subway coach in order to simulate effect time variation. Fixed values for each category (increase and decrease constants, maximum size and fire load) are used for calculation of fire growth, time to reach maximum size, duration and decay. The values are based on modifying international tests. With fixed fire load, high size involves shorter duration time. Fan dimensioning must include the probability of fan destruction or force reduction with increasing temperatures. The temperature calculations showed that the significant thermal capacity in the mountain mass around the tunnel causes absorption of most of the fire gas even when the fire size was approaching 100 MW. Heating and expanding of tunnel air cause higher flow velocities. This involves increasing frictional forces and hence increasing pressure losses. These can be included by adding an equivalent length to the tunnel. Due to strong reduction of downwind temperature, there is just a slight increase in pressure loss. For long tunnels the added pressure loss effect is negligible.


    Access

    Access via TIB

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Tunnel fire size and temperature variations, smoke expansion losses


    Additional title:

    Tunnelfeuergröße und Temperaturvariationen, Rauchexpansionsverluste


    Contributors:


    Publication date :

    2003


    Size :

    8 Seiten, 6 Bilder, 1 Tabelle, 5 Quellen



    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    Review of Tunnel Fire and Smoke Simulations

    Rhodes, N. / American Public Transit Association | British Library Conference Proceedings | 1994


    Analysis of fire and smoke behaviour in the Channel Tunnel fire and the Mont-Blanc Tunnel Fire

    Bradbury, W. / Atkins, W. S. / University of Dundee et al. | British Library Conference Proceedings | 2001


    Control of smoke movement close to a tunnel fire

    Bettis, R. / Daish, N. / Jagger, S. et al. | British Library Conference Proceedings | 1995


    Long and Big Tunnel Fire Smoke Barrier Water Curtain

    Hao, S. / American Society of Civil Engineers | British Library Conference Proceedings | 2010


    Study of Fire Smoke Flow of Tunnel at Different Longitudinal Ventilation

    Yang, Pei-Pei / Shi, Xiao-Lu / Shi, Bi-Ming | Tema Archive | 2012