Black Hole Vent BM720

Black Hole Vent BM720



  • 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&
  • Reversible for both high or low level mounting.
  • Screw covers for flush finish.

‘Black Hole’ Ventilator

Stops Wind Blasting In

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.


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 ’

Wall Thickness

Minimum 290mm (11 1/2”) Maximum 390mm (15 1/2”)

Page updated 4th Jun 2014, 10:51
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