EFS Multi-Blade fire damper is UL is rated as a 1-1/2 hour fire damper for use in dynamic systems, per IS 1001 part 3 (UL 555).

As a life safety fire damper, it has a failsafe design which enables the damper to automatically close upon the detection of heat and/or loss of power. The electric heat responsive device enables controlled closure through the actuator and is automatically remotely reset after testing or power failure conditions.

EFS dynamic Fire damper provides a low pressure drop design, qualified to 2,000 ft/min fpm (10.2 m/s) and  4.0 in. WC (1.0 kPa) and can be installed in vertical walls and partitions, or horizontally in floors or assemblies with fire resistance ratings up to 2 hours.