Introduction of Tunnel Ventilation Damper

Tunnel ventilation dampers are designed for enclosed vehicular tunnels, enclosedintro1.jpg parking structures, bus terminals and particularly for rapid transit system with long tunnels where mechanical ventilation becomes essential in order to supplement the natural ventilation from the piston effect of moving trains within the tunnel. This is to ensure that environmental pollutant level and temperature within such structures are maintained at acceptable levels. In addition, the dampers play a vital role in controlling the direction of airflow and migration of smoke within the tunnels during emergency ventilation activation as a result of fire within the tunnel. The emergency ventilation allows rapid removal of smoke and heat within the tunnel to permit safe evacuation of the train occupants and the entry of fire fighting personnel to the scene of fire.

The figure below shows a typical application of the tunnel ventilation dampers in a subway tunnel with combined natural and forced ventilation. During normal operation, damper 1 may be closed and damper 2 opened to allow the escape of contaminated air through the ventilated shafts. If necessary, damper 1 may be opened to allow for additional ventilation by the reversible flow fan.


During emergencies, when forced ventilation is required, damper 2 will be closed and damper 1 will be opened to allow for the removal of smoke and hear, or the supply of fresh air to the tunnel, depending on the locations of the stalled train and fire. The dampers on the ventilation shafts on the opposite end of the stalled train will be opened for smoke removal.

When interlocked with the tunnel ventilation system and integrated into the automation system for central control and monitoring, the tunnel ventilation dampers with externally powered electric or pneumatic actuators serve as live support systems in the subway tunnels. As tunnel ventilation dampers are used to control the movement of smoke during a fire, the dampers and their actuators must be able to operate at elevated temperatures and have a safety feature that allows them to assume the fail-safe position during power interruption. It is therefore important that tunnel ventilation damper is tested to appropriate standards for prove of its reliability as a smoke damper.

With OLS’s expertise and many years of dedication to research and product development, the SD60 tunnel ventilation damper is one of the many quality products that OLS has developed for the industry. Designed to suit exact applications, client’s specifications and statutory regulations, the SD60 tunnel ventilation damper has been developed for use in subways for underground tunnel ventilation systems that require heavy-duty dampers.


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