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The level of fire classification required in glass block applications will always be a condition of building regulations or building control. The fire ratings required are wholly dependent on the location or area of use. Architect specification should ensure all aspects of the project are considered in line with approval. 

TF blocks can be used internally or externally. Common applications are areas such as fire escape routes, areas within apartment dwellings, corridors, where a private space is adjacent to a communal area, external boundary or perimeter walls, loft conversions or garages or in close proximity to other buildings or public highways.

Fire ratings explained – specific to glass blocks

There are two specific areas of criteria: fire integrity and thermal isolation:

  • Fire integrity is the length of time the wall will remain stable in a fire. 
  • Thermal isolation relates to the time it takes for significant heat to transfer from the side of the fire through the complete glass block. For the purpose of an escape corridor this is critically important in respect of heat coming into contact with people evacuating via the escape route.

The 190x190x80 and 100mm La Rochere (standard) glass blocks achieve 60-minute integrity and 15 minute thermal isolation.

The La Rochere TF range comprises: 

  • TF30 achieves 60-minute integrity and 30-minute thermal isolation.
  • TF60 achieves 60-minute integrity and 60-minute thermal isolation.








Light Transmission





2.90 W/m2 OC

1.94 W/m2 OC

1.60 W/m2 OC

Fire Rating

60 mins / 15 mins

60 mins / 30 mins

60 mins / 60 mins

Compressive Strength

18.0 N/mm2

18.0 N/mm2

18.0 N/mm2

Weight / Block




Impact Strength 12.0 N/mm 12.0 N/mm 12.0 N/mm
Sound Transmissions Rw = 42dB

Rw = 48-53dB

Rw = 48-53dB

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