Tamarack Cape Back Draft Damper 7 inch diameter - TTi-CBD7
Product ID • CAPECBD70043
The Cape Backdraft Damper TTi-CBD7 is the ultimate one way air flow valve, designed to overcome the inefficiencies and limitations of traditional gravity or butterfly dampers on your bathroom fan. The TTi-CBD7 accomodates 7 inch duct.
The Tamarack Cape Damper consists of a specially formulated fabric sleeve attached to an outer metal sleeve. The fabric sleeve will allow air to pass through in the desired direction of flow with miniscule reduction in airflow. For reverse airflow, airflow that should be stopped by a backdraft damper, the Cape Damper gives a better seal at a lower pressure and holds that seal as the pressure increases. The Cape Damper is quiet, with no metal clanging sounds, and can be installed in a horizontal or vertical orientation.
The Tamarack Cape Damper was tested against two other dampers at a moderate airflow, the kind of airflow in a residential application. First the fan was run through plain duct to set the desired airflow. Then each type of damper was inserted into the same duct to measure the airflow.
7 inch duct and 4 Foot length with no dampers installed - 80 cfm
With Butterfly Damper installed in open position - 17 cfm
With Gravity Damper in open position - 30 cfm
With Tamarack Cape Damper in open position - 77 cfm
The other dampers decrease system efficiency by adding static pressure in the direction of desired airflow. For reverse airflow, the same test was used. Because all of these dampers are reasonably effective at stopping air, the next section compares leakage rates. Product with Damper Closed Resulting Airflow in CFM
With Butterfly Damper Closed position Leakage - 1.6 cfm
With Gravity Damper Closed position Leakage - 3.0 cfm
With Tamarack Cape Damper Closed position Leakage - .4 cfm
The Cape Damper works as well or better than other dampers at stopping undesired airflow. The Cape Backdraft Damper is far superior at allowing unrestricted airflow in the desired direction of flow; it doesn't steal away system efficiency. The Cape Damper is quiet, no metal clanging sounds and it can be installed in a horizontal or vertical orientation.