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TF Collection

The TF collection is a specialist performance range designed to meet stringent building regulations concerning fire rating, U-value performance and acoustic reduction.

The collection comprises two products available in Flemish, transparent, bubble and frosted patterns. 

  • TF60 (190x190x150mm)

General characteristics and why TFs differ from standard glass blocks

TFs are specialist glass blocks. Standard glass blocks (190x190x80mm/100mm) have two faces 8–10mm thick with one cavity. The TF60 is 150mm thick but has six face layers 8–10mm thick and three cavities. These features attribute to the fire ratings, U-value performance and acoustic absorbency achieved, all tested and certified in line with European standards.

TF fire protection

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.

TF60 connection detail

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

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

TF fire testing, test results and panel restrictions

a) Mechanical Resistance - the glass block wall must stay upright without too much damage following testing

b) Thermal isolation

c) Imperviousness against blaze

d) No flammable emission during testing.


The glass block wall must pass Test (a), (c) and (d) above.


The glass block wall must pass all four criteria (a), (b), (c) and (d).

When carrying out fire tests the results for both integrity and thermal isolation are measured in 15-minute increments. Certification is available for 15, 30, and 60 minutes. If a test fails at 28 minutes, this is classified as passing at 15 minutes, not upgraded to 30 minutes.

When a panel is tested for fire, not only the block is tested, but the complete system, encompassing the mortar, amount of reinforcement, joint dimension, perimeter expansion joint and fire-retardant sealant, forming the basis of how fire glass blocks should be specified and installed. 

The maximum panel size permissible is 9m2 (in line with original test). The width or height must not exceed 6m in either direction. 

TF blocks must be constructed in accordance with the original test to comply and validate test certification. 

TF blocks are tested to EN 1364-1 at CTICM [France] and assessed to suit the UK market by (Bodycote) Warrington Fire Research Centre to BS EN 1364-1. Test data held for TF collection: TF30 report number 169767 and TF60 report number is 169768.



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