Cavity Barriers

Silverliner® OSCB Horizontal Cavity Barrier

Silverliner® Open State Cavity Barrier (OSCB) is developed to protect the voids between the outer façade and the inner construction element of the building.

The product is designed for use in a ventilated façade, typically used in horizontal applications at floor junctions and around window openings.

The Silverliner® OSCB allows for 25mm or 50mm linear air gap to ensure movement of air and drain any moisture within the façade.

The aluminium foil restricts fibre migration and offers a class ‘0’ rating.

In the event of a fire the intumescent outer edge of the product will expand and close the ventilation gap between the product and the façade preventing the passage of fire and smoke from one compartment to another.

The Product comes in four different versions, achieving different air gaps and fire performance as follows:- 

OSBC 1 - 25mm Air Gap, (E) Integrity 90 / (I) Insulation 30

OSBC 2 - 50mm Air Gap, (E) Integrity 60 / (I) Insulation 30

OSBC 3 - 25mm Air Gap, (E) Integrity 120 / (I) Insulation 120

OSBC 4 - 50mm Air Gap, (E) Integrity 90 / (I) Insulation 60 (Void Size 54 - 354mm)

OSBC 4 - 50mm Air Gap, (E) Integrity 60 / (I) Insulation 60 (Void Size 355 - 550mm)



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  • Typical Façade Types
  • Technical Characteristics
  • Approvals


    ASFP TGD19:“Open State” Cavity Barrier used in External Envelope or Fabric of Buildings.

    This test exposes the cavity barrier to a specified regime of heating and pressure specified in EN1363-1. 

  • Building Materials


    Block, masonry, aerated concrete and concrete must be within a density range of 450 to 2300kg/m³. CP
    (cement particle) board and concrete cladding must be within a density range of 450 to 2300kg/m³. Timber
    must have a minimum density of 510kg/m³. All substrates must have at least the same Fire Resistance as is
    required by the fire stopping system.




    - Between the inner substrate and the external building envelope
    - In conjunction with Paraflam® where vertical Cavity Barriers are required
    - Where movement of air and moisture is required
    - Systems to cover void ranges from 2mm - 550mm


  • Total Void Size ≤ 550mm
    Air Gap ≤ 50mm
    Fire Resistance Up to 120 minutes tested in accordance with ASFP TGD 19
    Ventilation Void Closure Time ≤ 5 minutes

    Product Dimensions

    1000mm x 75mm (width is variable depending on building requirements)

    1000mm x 120mm (width is variable depending on building requirements)

    Density Mineral fibre 80kg/m³
    Brackets Steel - 1.5mm thickness, 390mm or 635mm length For product size in excess of 300mm (w) use 635mm
    Fixings 3 brackets per 1000mm @250mm centres (length
    390mm or 635mm)