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Double Sized Air Brick Black Hole Ventilator - 71,500 Btu/h

Model: K-BM720
Search: QS2849
  • Double Sized Air Brick Black Hole Ventilator - 71,500 Btu/h
  • Double Sized Air Brick Black Hole Ventilator - 71,500 Btu/h
  • Double Sized Air Brick Black Hole Ventilator - 71,500 Btu/h
  • Double Sized Air Brick Black Hole Ventilator - 71,500 Btu/h
Availability: 2 to 7 days
 £47.38 Inc VAT
  • DETAILS
    • Free Air: 70cm² Anti-draught ‘Black Hole' ventilator BM720
    • Rated Input - Max 21kW (71,500 Btu/h)
    • ‘The Original Black Hole Ventilator' Comprising; Double rustic red louvred airbrick, cavity liner with cavity drip and anti-draught baffles, extension piece and white inner grille.
    • Invertible for high or low fitting.
    • Expands to fit solid or cavity walls 290mm to 390mm

    The BLACK HOLE Ventilation range

    ‘Black Hole' ventilation products provide the
    answer to the dangerous practice of
    ventilators being blocked off by occupiers who
    are being annoyed by draughts. This makes an
    important contribution to safety. New tests
    show that while this works the ventilator may
    not pass the required amount of air when the
    appliance is operating.
    THEREFORE IT IS IMPORTANT THAT A
    SPILLAGE TEST IS CARRIED OUT AS
    REQUIRED BY THE BRITISH STANDARD
    AND CORGI GOOD PRACTICE
    The benefits of a ‘Black Hole'
    The ‘Black Hole' magic explained
    As outside wind pressure increases, a normal
    ventilator lets more air through causing
    annoying draughts.
    Inside the Stadium ‘Black Hole' Ventilator
    vortices are formed behind the internal
    blades as the incoming air is forced to change
    direction. The gap that the air is able to pass
    through narrows. As wind pressure increases,
    the vortices grow, so reducing the total air
    flow, finally tumbling and slowing to a trickle,
    thereby cutting down annoying draughts.
    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 - the
    occupier cannot see through the ventilator
    and is less likely to be worried that insects
    and vermin may enter the house through it.
    Stops light shining out - night flying insects
    like moths, crane flies and mosquitoes are
    not attracted in.
    Absorbs outside noise - reduces the
    penetration of traffic noise. The internal
    construction works as a sound baffle.
    Allows air to be pulled through by the
    appliance when it is operating.
    Safety - with draught and light annoyance
    problems eliminated, the occupier will not
    be tempted to block off the vent.
    However, when the heating appliance is
    operating, air is drawn through the vent and
    actually speeds up within the constricted air
    flow between the vortices, thus maintaining
    the correct amount of air into the room or
    compartment to allow the fuel to burn
    efficiently and flue gases to escape.
    When the appliance is not working, incoming
    air is reduced to a minimum, even on windy
    days. The actual physical difference is that of
    air blown or drawn. The energy of the blown
    air (wind) is quickly dissipated by the
    restriction of the internal shape and the
    vortices, while the drawn air will flow
    smoothly round the vortices.
    BS 5440 Part 2, 2000:
    Several changes have been made to update
    the previous ventilation standard. Three of
    the main ones are summed up below but as
    with all new standards they are not
    retrospective.
    1. The previous words ‘Free Air Space' are
    replaced by ‘Free Area' measured and
    Effective ‘Free Area' (see point 3).
    2. The ‘Free Area' requirement has been
    increased from 4.5cm2 to 5cm2 per kW above
    7kW input rating.
    3. Complex and anti-draught ventilators shall
    be measured by the volume of air that they
    will pass i.e. the ‘EFFECTIVE FREE AREA' .
    The ventilator should be marked accordingly.

  • TECHNICAL

    Technical Specifications

    Product Type Black Hole
    Product Group Passive Ventilators
    Free air (cm²) - Max 70
    Colour - Internal White
    Colour - External Brown
    Packaged Weight (Kg) 1.6
    Packaged Length (mm) 270
    Packaged Width (mm) 300
    Packaged Height (mm) 210
    Barcode 5060272545451
    Barcode - Type EAN
    Quick Search: QS2849
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  • DELIVERY
    Delivery: You'll receive in: Cost Min Order
    Free Delivery 3 to 5 Days FREE £100
    Standard 2 to 4 Days £4.99 -
    Express Courier Next day+ £9.95 Any

    View Full Delivery Info

    FREE Delivery for orders over £100 inc VAT.

    + Order before noon for Next Working Day Delivery for items in stock

    Excludes Highlands, Islands, and Certain Postcodes.

    Please Note:
    Ducting tubes over 200mm in diameter and 3 metres in length may incur additional shipping charges.

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