Requirements for Escape Doors in the Tunnels of the Koralm Railway Line – Special Focus on Thermal Loads During Fire

As escape ways are an integral part of rail tunnel safety, the escape doors themselves require
particular attention. The doors must be solid enough to withstand the high pressure fluctuations
caused by high-speed rail traffic, and must also be capable of withstanding high temperatures.
This paper focuses on the defined temperature requirement for escape doors in the
Koralmtunnel. Various regulations define the temperature requirements, e.g. for concrete
surfaces. These requirements define temperature levels and exposure times in the form of timetemperature
curves. As there is no uniform international standard, the requirements imposed
depend more or less on national policy. Well-known temperature curves are the HC curve, the
HC-increased curve, and the ‘standard fire time-temperature curve’, in accordance with EN
13501-2. All of these differ in terms of maximum temperature value, time dependent increase
in temperature, and duration of temperature exposure.
In order to define a credible temperature requirement for tunnel doors, numerical investigations
were performed taking an incident with a maximum heat release rate of 100 MW as a thermal
boundary condition. These investigations resulted in a time-temperature curve which could be
used in testing the fire resistance of escape doors. The results from an analysis of temperature
and heat release data from full-scale fire tests up to 200 MW peak heat release confirmed the
validity of the newly-defined test conditions. It turns out that the ‘standard fire time-temperature
curve’, as defined in EN 13501-2, represents reliable test conditions.