Cavity Barriers

FBB-VS Horizontal Cavity Barrier

FFB-VS Open State Cavity Barrier is developed to protect the voids between the outer facade and the inner construction on element of the building.

FFB-VS a foil-faced stone wool pre-cut unit, which has a powerful intumescent graphite strip bonded to the exposed face. The intumescent graphite strip is pre-wrapped with a durable polythene adhesive sheet to prevent water ingress.

FFB-VS has been designed to provide a 25 mm air gap, that allows air flow and moisture to pass down the back of the cladding. Under fire conditions, the powerful intumescent along the front edge expands horizontally to close the gap and prevent the passage of fire.

Horizontal fire barriers offer an expected life expectancy of over 25 years. Tested to suit voids up to 450mm deep to; BS476 to 120 and 60 minutes, and acoustic isolation on testing to EN10140 to 39 dB (non-ventilated).

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  • Typical Façade Types
  • Technical Characteristics
  • Advantages


    Fire resistant testing to BS476 to 120 and 60 minutes

    Acoustic isolation on testing to EN10140 to 39 dB (non-ventilated)

    Suitable for close up to 25 mm ventilation gap

    Voids up to 450 mm wide

    Free of halogens, asbestos, fibres and silica and is non-toxic

    Life expectancy of over 25 years

    Contributes to green building

  • Building Materials


    Concrete slabs, columns and walls

    Curtain wall assemblies

    Stone cladding, etc.




    Horizontal and vertical cavities between the inner and outer construction elements


  • Description Foil faced stone with a black intumescent edge
    Fire resistance - FFB-VS BS467 20/22 60 min., DIN 4102 B2 - 30/30
    Closure time - FFB-VS needs to be > 5 min
    Activation Approx. 180 °C (intumescent material)
    Expansion pressure Approx. 07 N/mm2
    Density Stone wool - 80 kg/m3 intumescent 1.3 g/cm3
    Weather resistance Yes
    Sag 0 %
    Open void size - FBB-VS 25 mm to 50 mm
    Dimensions 75 mm Thick 1000 mm Long
    Width FBB-VS (30 mm to 450 mm)
    Brackets FBB-VS (3 per unit)