The primary function of the smoke protection/exhaust separation wall is to separate the airflow conditions between adjacent tunnel bores. Air turbulence can disrupt the natural airflow in one bore by drawing air out of the adjacent one. The separation wall prevents such turbulence and ensures that the airflow within each tunnel bore is maintained in a controlled manner.
Additionally, the so-called chimney effect during a fire is specifically influenced. In the event of a tunnel fire, hot air and smoke rise and exit through the tunnel portal. The smoke protection/exhaust separation wall ensures that this hot smoke does not spread from one bore into the neighbouring one. Without such a barrier, smoke could spread uncontrollably into the adjacent bore, significantly hindering evacuation and rescue operations.
These walls must also withstand high thermal loads during a fire and must not lose their structural integrity even under intense heat. Concrete proves particularly advantageous in this context, as it has a high fire resistance and largely retains its load-bearing capacity even at extreme temperatures. This ensures the protective function of the smoke protection/exhaust separation wall even under the most demanding conditions.
The modular integrated systems REBLOC NBH150XA and NBL100X, made of precast concrete elements, are ideally suited to meet the diverse requirements at tunnel portals. The particular benefit of this solution lies in the fact that these constructions are tested vehicle restraint systems according to EN 1317 with containment levels H4b and H2, thereby ensuring a high level of safety for road users. Depending on requirements, heights of up to 8 metres can be achieved. According to the required height, the systems are either free standing or anchored, whereby the shallow anchoring depth of a maximum of 220 mm prevents interference with installations in the ground in front of the tunnel portal (e.g. cables).
Thanks to the modular design and short installation time, the system is also ideally suited for retrofitting existing tunnel structures.