Market leading intumescent louvre system for fire doors

FBLS - Fire Block Louvre System

Air Transfer Grilles for Fire Doors

Fully tested louvre system for timber and steel fire doors, installed with confidence for over 20 years. Widest range of sizes available from stock, including 'full door'. Complete system including our unique intumescent block, and two heavy duty steel louvres.

  • Suitable for steel doors up to 240 minutes - To BS EN 1634-1:2014
  • Suitable for 30 and 60 minute timber fire doors - To BS 476-22:1987
  • Complete system – not just an intumescent block
  • Heavy duty steel louvres
  • Over 25 sizes from stock available immediately
  • ‘Full door’ sizes available (steel doors only)
  • Non-vision for privacy
  • 40% free area allowing good bi-directional air flow
  • Suits doors of 44mm minimum thickness – no maximum thickness

FBLS Fire Test


The FBLS is a complete fire rated louvre system, consisting of a centrally mounted intumescent block, intumescent aperture liner (timber doors only), and a 2 part steel louvre fixed to both sides of the door. Standard louvres allow ventilation but will also allow the passage of flames and hot smoke, the intumescent contained within the FBLS system expands, filling the void and maintaining the integrity of the door.


FBLS Drawing


As the FB intumescent block contained within the FBLS system is only 14mm thick, the slim thickness enables it to be used with heavy duty steel louvres even on 44mm thick doors. This allows the specification of the FBLS for commercial and industrial applications. Examples are doors to plant rooms, stores, computer rooms, changing facilities and manufacturing areas. In fact, any area that requires ventilation but is protected by a fire rated door.

Full technical details can be found on the individual product pages.

Fbls Fire Block Louvre SystemFbls Fire Block Louvre System 356X356Mm (14X14In)
FBLS Fire Block Louvre System
From £269.51
Only 1 unit left
Intumescent Block FbIntumescent Block Fb 606X606Mm (24X24In)
Intumescent Block – FB
From £105.47
In stock, 83 units