Lau’s light duty counter balanced aluminum backdraft damper is an extremely sensitive gravity operated backdraft damper. Counterbalance weights can be set to relieve air at pressure differentials less than .01 inches w.g. Provides excellent weather protection when installed in exterior walls.
Lau’s medium duty counter balanced aluminum backdraft damper is designed for gravity relief at relatively low pressure differentials and low velocity airflow. Adjustable counterbalance weights enable the damper to operate in the range of .01 to .05 inches water gauge.
Lau also offers a heavy duty counter balanced aluminum backdraft which is weather resistant for relief air applications in exterior walls. This specially counter balanced unit will relieve at extremely low pressures (approximately .02 inches w.g.). It is also of rugged design and heavy duty construction, allowing the handling of large air flows. Maximum spot velocities up to 3500 FPM.