Underground transport and rail systems become more and more frequent as they allow rapid transit times while transporting a large number of users. The network of high speed trains and also standard rails are more and more transferred to underground tunnels in order to mitigate the environmental impact.
Both applications need ventilation rates. In Metros the influx of a large number of people and the presence of moving trains generate a reduction of oxygen and an increase in heat and pollutant. Mechanical ventilation is then required to achieve the necessary air exchange and grant users of the underground train systems comfortable conditions.Ventilation systems have a second and even more important purpose. That is to guarantee safety in case of fire emergency. In order to create a safe and clean environment for escaping mechanical ventilation both in tunnels and in the stations is activated. In rails the ventilation of tunnels is mainly dedicated to fire emergencies where it is vital to keep under control the smoke propagation and create safe areas and clear environment for the users.
In the Road, Metros and Trains tunnels where safe areas are foreseen Systemair can provide a full product package so to satisfy the needs. Safe areas are often pressurized and suitable fans, grilles, overpressure dampers and fire dampers can be used to create the positive required pressure, normally between 30 to 80 Pa.