March 5, 2021

Fire Safety and A1 Fire-rated Ducting Explained

Following the tragic Grenfell Tower fire, the government commissioned an independent review of the Building Regulations and fire safety.  Recommendations in the report quickly resulted in changes to regulations banning the use of combustible materials in the external walls of relevant buildings above 18m (11m in Scotland).

Consequently, since December 2018, all materials or products used in the external walls of multi-storey buildings containing one or more dwellings, are required to be non-combustible to European fire classification A1 or A2-s1, d0.  This includes anything located within any space forming part of the wall and includes:

  • external grilles,
  • air bricks,
  • MVHR and extract ducting (until clear of the internal plasterboard), and
  • cavity weep hole ducts.

During 2018 Rytons tailor-made service had made several orders of metal air bricks and plenum adaptors for developers of high-rise buildings.  This allowed us to move quickly to satisfy the industry’s new requirement for non-combustible ventilators, launching a unique range of A1 fire-rated air bricks and ducting kits for HVAC and extract ducting.

Rytons A1 range provides:

  • Fire-rated MVHR and extract ducting to replace plastic components during AMC cladding removal.
  • Fire-rated ducting kits in new build multi-storey developments, e.g. apartment blocks, student accommodation.
  • Fire-rated refurbishment ducting in the re-development of commercial buildings, e.g. old factories, into multi-storey residential buildings.

Compatible with the most widely used MVHR systems and extract ducting, Rytons A1® Fire-rated Ducting Kits span four rectangular ranges: 110x54mm, 204x60mm single, 204x60mm double and 220x90mm, plus three circular ranges: 100mm dia, 125mm dia and 150mm dia.

The four A1 fire-rated rectangular ducting ranges comprise:

  • Straight ducting kit with connector for plastic ducting
  • Refurbishment ducting kit sized for fitting over in-situ plastic ducting
  • 90° balcony kit with connector for plastic ducting
  • 90° refurbishment balcony kit sized for fitting over in-situ plastic ducting
  • S shape ducting kit for offset window head and ceiling voids

The three A1 fire-rated circular ducting ranges comprise:

  • Round ducting kit with rectangular connector for plastic ducting
  • Round ducting kit with round connector for plastic ducting

Each kit is hand-made to order.  Size, length, air brick and RAL colour are customisable to the design of the building.  Delivered to site in one piece, there is no requirement for screw fixing or joint sealing before installation.  This not only saves on labour but ensures factory sealed, airtight joints throughout.

Unique buildings and complex refurbishments can call for bespoke items.  Here, we can work hand-in-hand with clients to design, fabricate and supply the perfect solution.  Using platforms such as Teams and Facetime, we can discuss available options and demonstrate modifications.

Bespoke A1 fire-rated items include:

  • A1 fire-rated plenum adaptors with multiple ducting connectors
  • A1 fire-rated ducting kits with unique grille designs
  • A1 fire-rated soldier air bricks
  • A1 fire-rated brick slip air bricks
  • A1 fire-rated ducting with precise degree bends
  • A1 fire-rated ducting 2m long
  • A1 fire-rated background ventilators

A selection of images can be found on our A1 fire-rated metal special product gallery.

Rytons A1 range also includes fire-rated metal air bricks, fire-rated metal sub-floor ventilator, fire-rated metal party wall venting sleeve, and fire-rated metal Rytweep® cavity weep hole duct.

Rytons A1® Fire-rated Metal Air Bricks Double

Rytons A1® Fire-rated Periscope® Underfloor Ventilator with Single Air Brick Grille

Rytons A1® Fire-rated 9×3 AirLiner® with Single Air Brick Grille

Rytons A1® Fire-rated Metal Rytweep®

For further information, or to discuss any A1 ventilation requirements, please do not hesitate to email or call 01536 511874.

Useful Information:


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

While every effort has been made to ensure the accuracy of this information, no guarantee is given, nor responsibility is taken for errors or omissions.  Customers should satisfy themselves with the regulations and that the products are suitable for the intended purpose.

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