Fire-rated Glazing Systems

Fire-rated glazing systems offer passive fire resistance. They have a fire property or function which does not warn of, or extinguish, fire. Fire resistance is defined as: The ability of an element of construction to perform its design function during exposure to fire.

A fire-resistant glazed system comprises glass, a frame and a glazing and fixing method.

The system is only as effective as the weakest part. All the elements must be designed, specified and installed to meet the required performance.

All fire-rated systems installed by GLASSOLUTIONS CONTRACTING are quality audited under ISO 9001.

GLASSOLUTIONS design, supply and install a full range of fire resistant glass from its sister company VETROTECH SAINT-GOBAIN.

Design criteria

The system must pass a British Standard test in this country and prove to give protection for a specified time.

The level of resistance required depends upon the application of the installation and definitions are covered in Building Regulations

Document B Fire Safety. BS PD 6512: Part 3 Guide to the Fire Performance of Glass outlines fire performances of glass:

  • External Fire Exposure (BS 476 part 3)
  • Non-combustibility (BS 476 part 4)
  • Fire Propagation Index (BS 476 part 6)
  • Surface Spread Of Flame (BS 476 part 7)

BS 476:

Part 22 Fire Tests on Building Materials and Structures applies to all fire-resistant materials. It details test methods to be used and defines performance criteria for building materials

BS 476:

Defines two criteria that specify the level of fire resistance offered:

Resistance to the passage of flames or smoke.

The collapse or escape of flames or smoke.

Stops the transfer of radiant heat.

If the average mean or spot temperature is exceeded (140°C and 180°C respectively).

Performance criteria

The tests carried out under BS 476 lead to the definition of performance criteria for fire-resistant glazed systems. For example, a 30/30 performance refers to 30 minutes integrity and 30 minutes insulation

It is vital that the testing covers the whole system. Any design must not exceed the glass manufacturer’s tested sizes glazed in the correct frame material for those sizes.



fire protection.

When specifying a fire rated glass system, one should consider:

  • fire-resistance performance criteria integrity and/or insulation 30 / 60 / 90 / 120 minutes
  • internal or external application
  • safety and security requirements
  • acoustic or thermal performance
  • aesthetic preference
  • frame type and finish
  • fixing details.

All installations are carried out in accordance with the GLASSOLUTIONS CONTRACTING preferred glazing methods and are checked and audited as part of the Quality Management System and to meet the requirements of BS EN ISO 9001.


Generally there are two materials used for framing fire rated installations:

Timber systems

Timber based framing systems typically give a maximum fire-resistance performance generally 60/60.

Essential features include:

  • timber main frame
  • timber beads/steel angles
  • fire-resistant channel systems
  • intumescent mastic between the glass and bead, bead and frame. Generally:
  • 30 minutes can utilise soft woods with a minimum density of 470 kg/m3
  • 60 minutes can utilise hardwoods with a minimum density of 650 kg/m3

Steel systems

Steel-framed systems can give extended fire-resistant performance times ranging from 30 / 30 to 120 / 120 minutes. They can glaze larger areas than timber frames, provided the glazing area does not exceed that tested.

A range of finishes can increase aesthetic choice by powder coating, and aluminium and timber cladding.