ACFIRE125 – Rytons 125mm AirCore® Intumescent RytBlock

General Details
  • Heavy-duty intumescent air transfer grille for doors, walls and ducts.
  • In the event of a fire, the slats fuse and give a complete seal in 2 minutes.
  • Gives up to 2 hours resistance to fire.
  • EI rating of 2 hours when used with a cover grille.
  • Tested in accordance with BS 476 Parts 20 and 22:1987, BS EN 1634-1:2014, BS EN 1364-5:2017 and NEN 6069:2005+A1:2016.
  • Galvanised steel framework protects graphite intumescent core by preventing inward deformation.
  • Suitable for use in external walls and areas with high humidity.
  • May be used horizontally or vertically.
  • Compatible with Rytons 125mm Dia. AirCore® range.

Free Area:

  • 5,150mm² (51.5cm²) per unit.


  • 118mm Dia. x 43mm D (see image gallery above).
  • CAD drawing available by email.


  • Steel grey.


  • Z275 galvanised steel framework.
  • Metal slats with graphite intumescent core.


  • Refer to the Documents tab above for fitting instructions according to application.
  • Insert into Rytons 125mm Dia. AirCore® tube and bed into position with an intumescent sealant.
  • Due to the majority of house fires starting inside the home, we recommend positioning the block at the internal end of the tube.
  • Alternatively/additionally, if there is an identified risk of a fire starting externally, position the intumescent block behind the external grille.
  • The upper edge of the intumescent grille should be no higher than 3m from floor level.
  • The lower edge of the intumescent grille should be no closer than 200mm to floor level.

Handling Information:

  • Weight: 0.17kg.

Reference Material:

  • BS 476-20:1987 – Fire tests on building materials and structures.  Method for determination of the fire resistance of elements of construction (general principles).
  • BS 476-22:1987 – Fire tests on building materials and structures.  Method for determination of the fire resistance of non-loadbearing elements of construction.
  • BS EN 1634-1:2014 – Fire resistance and smoke control tests for door and shutter assemblies, openable windows and elements of building hardware.  Fire resistance test for door and shutter assemblies and openable windows.
  • BS EN 1364-5:2017 – Fire resistance tests for non-loadbearing elements.  Air transfer grilles.
  • European fire protection classification EI (Insulation).  The ability of a specimen of a separating element to restrict the temperature rise of the unexposed face to below specified levels.

NBS Specification:


Rytons is proud to be a family run business and British manufacturer since 1972

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