A leading louver and damper manufacture needed an electric failsafe operator that could endure a tunnel fire and still operate the ventilation system (without an external power source). To qualify, the unit had to undergo a 2HR burn test that required it to “bake” at 500 deg F for 2 hours, while being cycled every 15 minutes.
Our solution was an electric actuator with a patented mechanical spring back-up feature. On startup, the internal spring cartridge is wound to store enough energy to close the dampers when there is a system upset. Under normal conditions, the unit operates on standard, compact, high efficiency motors and drive trains. When the actuator senses a loss of power, the spring cage assembly will unlatch and drive the damper open to allow airflow. The real challenge was to do it in a fire.
Working with an insulation specialist, we designed a wire mesh and fire resistant fabric blanket to encase and protect the actuator from the transfer of external heat to the temperature sensitive electronics housed under the cover.
Our actuator survived the burn test and kept on running, enabling our manufacture to offer an additional safety feature in their tunnel projects.