When smoke is detected in the protected area, a smoke sensor sends a signal to the main operational control panel. The control panel connects all parts of the system.
An electro-mechanical damper will open on the “fire floor” into the protected vertical smoke shaft. This is the escape route for the smoke laden air. Beacon Tower has two of these smoke shafts, one on either side of the building.
Fire rated smoke ventilation fans located at the top of the shafts, will start and draw the smoke / air mixture up and out of the exhaust duct. The operation of the fan system will cause a negative pressure in the protected lobby. Dyer ensure that the fire door into the stairway is hinged so that this pressure will pull the door open. At the same time, a Smoke Heat Exhaust Ventilator (SHEV) will open at the top of the stairs to allow fresh air into the staircase.
On this project the SHEV is a certified roof ventilator or Skylight and can be opened safely to allow roof access when required. Opening the SHEV ensures that the stairs are kept free from any smoke as the fans system continues to work to clear smoke laden air.