CBD.. Backdraft Shutters for Centrifugal Roof Units

These shutters are designed to fit inside the unit base and be positioned on the roof curb before fitting the roof unit. The curb surface must be flat to permit an airtight seal.

CBD backdraft shutters have a galvanised steel frame and extruded PVC flaps; the flap spindles run in nylon bushes.

For high temperature applications the flaps can be fabricated from galvanised steel. High temperature conditions must be nominated at the time of enquiry.

CBD backdraft shutters should be supplied as standard for twin fan units, for which they are an essential item to ensure there is no short-circuiting of the airstream.

They are an optional extra for single fan units.

The pressure loss through the dampers must be added to the system resistance before selecting the fan.