Fire safety glass and how it works

There are numerous examples of passive fire protection methods and products within the built environment. Fire safety glass is one.

Fire safety glass can be a key part of a building’s passive fire protection strategy so FMs need to be aware of the different classifications and the performance of each, as Richard Ainsworth group technical director at Pyroguard tells Facilitate Magazine.

Compartmentation – slow the spread of fire

Whether installed in fire doors, windows, internal partitions, or atriums, fire safety glass is there to provide a safe route of escape in the event of a fire and to help separate the building into a series of fire-safe compartments. This is compartmentation, a concept that underpins effective fire protection and helps to slow down the spread of a fire – the technical director explains.

The main classifications

According to British standards, there are three main classification levels of fire safety glass available, each with its own characteristics and level of protection offered. Facilities managers should always consult local regulations prior to any on-site installation to determine the classification of fire safety glass that is required – Richard Ainsworth points out.

Integrity (E)

Integrity glass or ‘E’ Classification offers the base level of performance. When exposed to a fire, it has been designed to stop flames and smoke from penetrating through onto the unexposed side. It does not prevent any transmission of heat in the event of a fire. ‘E’ glasses can be manufactured as modified toughened or cuttable wired and laminated glass.

Integrity and radiation (EW)

Like integrity glass, EW classification maintains the same level of protection against smoke and flame but, in addition, will also deliver a reduction in the amount of heat transmitted to the protected side. As the middle range glass, this is based on the radiated heat transfer being below 15 kW/m2 on the unexposed side for the duration of the fire. It is possible to have EW glasses manufactured in three different methods, as modified toughened, gel-filled toughened or cuttable laminated glass.

Integrity and insulation (EI)

Finally, glass that is classified EI offers the highest level of protection. As well as providing a strong barrier against smoke, flame and hot gases, EI also delivers a significant reduction in the amount of heat transferred through the glass, keeping the average temperature increase of the unexposed side to no more than 140°C above its starting temperature.

Reducing heat transmission might seem obvious, but…

Reducing heat transmission can be just as important to restrict the spread of a fire within a building as the protection against flame and hot gases. It may sound obvious, but building fires have the potential to reach unimaginably high temperatures, with heat impacting a person’s ability to escape safely in the same way that the physical flame can too.

In certain settings and conditions, it may be possible for items, such as papers or clothes, on the unexposed side of the partition to ignite just from the level of radiated heat transmitted, should the incorrect fire safety glass classification be installed – the expert says.

Fire safety glass only is not enough

Fire safety glass on its own is not enough and won’t guarantee the level of fire protection required. Instead, it is important to take a systematic approach when it comes to matters of fire safety, with fire safety glass only delivering its intended value if specified and installed as part of a tested and certificated system – Ainsworth highlights.

Whether it’s installed in a door or a partition, the glass will only be one component of the wider system, with the frame, seal and fixings all to be considered too. It is here that third-party certification is especially key and facility managers, contractors and installers should always refer to this primary test evidence and certification or follow the third-party approved specification carefully when dealing with a fire safety system.


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