Fire-rated glass is a specialised type of glazing designed to withstand high temperatures and contain flames and smoke.
The higher the fire rating, the longer the glass can withstand fire. This gives building occupants more time to evacuate the building and the emergency services longer to arrive.
Like all kinds of specialised glass, it works just as well as a standard piece of glass. It allows for visibility and the entrance of natural light while protecting escape routes and limiting the spread of fire.
Fire-rated glass is used in a wide range of contexts, both commercial and residential. It's commonly found in fire doors, escape corridors, stairwells and external facades. It's especially in demand in high-occupancy areas, such as high-rise dwellings, schools and hospitals.
For a glazing system to be fire-rated, the frame must be fire-rated as well as the glass. This applies whether the frame is made from aluminium or steel.
But what do we mean by fire-rated, exactly?
What are the different types of fire-rated glazing?
Fire-rated glass is rated in two ways: integrity and insulation.
Integrity covers the glass's ability to block flames and smoke. It's identified in glass product descriptions with the letter E.
Insulation, by contrast, blocks flames, smoke
and heat radiation. This is identified as "EI".
Both E-rated and EI-rated glass comes with a number. This represents the amount of time the glass can withstand flames, smoke and – in the case of EI-rated glass – heat radiation. Here are two examples:
- E30: the glass offers protection against flames and smoke for 30 minutes.
- EI120: the glass offers protection against flames, smoke
and heat radiation for 120 minutes.
The highest available fire rating is EI180, which provides protection against flames, smoke and heat radiation for 180 minutes (three hours).
What are the different types of fire-rated glazing?
There are several types of fire-rated glazing on the market. Here at Wrightstyle, our fire-rated glazing systems are fitted with laminated fire-rated glass.
This is similar to any other laminated glass unit in that it consists of two or more glass sheets bonded with an interlayer. In the case of fire-rated laminated glass, the interlayer turns opaque and swells when exposed to high temperatures.
Fire-rated laminated glass offers high insulation, absorbing energy and limiting the transfer of heat. It also has the advantages of non-fire-rated laminated glass – in particular, its superior strength, safe breakage pattern, noise reduction and thermal efficiency.
Other kinds of fire-rated glass include ceramic glass, wired glass and borosilicate glass.
Both ceramic and borosilicate glass are still used in high-risk installations. Wired glass, however, has declined because of its poor impact safety. It's now prohibited in high-risk locations by modern building codes.
How is fire-rated glazing tested?
Fire-rated glazing is tested by subjecting both glass and frames to intense furnace heat. This measures the unit's ability to maintain structural integrity and, if required, to limit heat transfer.
Depending on the fire-rated glazing being tested, the test verifies integrity (E) against flames and smoke and insulation (I) against heat transfer. Ratings run from 20 minutes to 180 minutes.
Here at Wrightstyle, we subject our steel-and-glass assemblies to intense furnace conditions. We simulate real-fire conditions to ensure our fire-rated systems meet UK, European and US standards.
What is a fire-rated glazing system?
Fire-rated glazing refers to a kind of specialised glass. A fire-rated glazing system, however, refers to the glass and the frame.
To qualify as fire-rated, the whole glazing system must be fire-rated – not just the glass. This entails the use of specialised frames and seals.
What standards cover fire-rated glazing?
