Fire Rated Glazing Explained

Fire rated glazing plays an important part in todays’ commercial building design. In fact fire-rated glass has been an important component in building safety for decades, however due to the specialised nature of the product it can present a challenge for those tasked with specifying the correct product.

Let’s start with the basic definition – namely - it is glass that has proven to offer a certain degree of protection in the face of fire. This means it can help keep flames and smoke from spreading from one part of a building to another. This capability is called is compartmentation, which as the name suggests involves containing the spread in “compartments” (rooms etc) and fire rated glass is very important in restricting fire to a limited area.

Where as all glass can withstand a certain amount of heat when exposed to fire there is a marked difference in capabilities between say float glass (which can last up to about 250°c) and glass rated for fire (upwards of 1600°c and beyond).

To earn a rating, any glass type or unit will need to undergo a series of tests which are carried out in accordance with national and european classifications. These tests establish the duration which the glass on test can withstand the smoke and flames and a classification or rating is assigned to it accordingly.

The performance characteristics of fire rated glazing can be categorized as follows: -

Integrity
The ability of a specimen of a separating element to contain a fire to specified criteria for collapse,
freedom from holes, cracks and fissures, and sustained flaming on the unexposed face.

Insulation
The ability of glazed screens or doors to limit the temperature rise on the non-fire side to an average
of no more than 140°C and in any one position by no more than 180°C .

Radiant Heat
The ability of the element of construction to reduce the probability of transmission of fire as a result of significant radiated heat, either through the element or from its unexposed surface to adjacent materials on the non-fire side.

And Relevant Fire Test Standards

BS 476 Fire tests on building materials and structures.
Part 20: General requirements.
Part 22: Methods for the determination of the
fire-resistance of non-loadbearing
elements of construction.

BS EN 1363 Fire resistance tests.
Part 1: General requirements.
Part 2: Alternative and additional procedures.

BS EN 1364 Fire resistance tests for
non-loadbearing elements.
Part 1: Walls.
Part 2: Ceiling (Non Load Bearing).
Part 4: Curtain Walling.

BS EN 1365
Part 2: Floors and roofs.

BS EN 1634 Fire resistance tests for door and
shutter assemblies.
Part 1: Fire doors and shutters.
Relevant Impact Safety Test Standards

BS 6206 specification for impact performance
requirements for flat safety glass & safety plastics
for use in buildings.

BS EN 12600 : 2002 Glass in building – pendulum
test. Impact test method and classification for
flat glass.