The air flow within the duct is slowed down by the change of direction and by the vortices formed, reducing draughts to a minimum.
Stops Light Showing Through: Occupier cannot see through it and is less likely to be worried that all manner of insects/creatures will come into the house.
Stops Light Shining Out: Night flying insects, such as moths, craneflies and mosquitoes, are not attracted in.
Absorbs Outside Noise: Reduces outside traffic noise. The internal shape works as a baffle.
Correct Amount of Air: The ‘Black Hole’ Ventilator allows only the right amount of air to be pulled through by the appliance when it is operating.
Safety: With the above problems eliminated, the occupier is less aware of the vent and so will not be tempted to block it off, which can and has led to dangerous situations.
Complies with BS 5440 Part 2, 2000. For use with open flued appliances with an input rating up to 21kW (71,000 Btu/h). ‘Effective Free Area 70cm2'
Airbrick Rustic Red Double size brick.
Cavity Liner Black plastic in two parts fixed together and with a continuous airway.
Centre joint with cavity drip.
Slider Extension Black plastic with four self-tapping screw holes to take the interior grille.
Inner grille 205 x 290mm (8” x 11 1/2“) white plastic marked “DO NOT BLOCK THIS VENT & EFFECTIVE FREE AREA”.
Reversible for both high or low level mounting.
Screw covers for flush finish.
Minimum 290mm (11 1/2”) Maximum 390mm (15 1/2”)