News & Events
What is Fire-Rated Glazing?

What is Fire-Rated Glazing?

Fire-rated glass is a specialist glazing product offered by Natralight for both skylights and structural glass units.

This has been developed by our team of specialists to provide robust protection in the case of a fire. For our latest blog, we are going to look at fire-rated glass in more detail and provide answers to all of your burning (excuse the pun) questions.

Float glass offers little protection from fire, tending to break at 120°C. Toughened glass or tempered glass lasts considerably longer than float glass, being able to withstand temperatures up to 260°C. For glass to be considered fire-rated though it must be capable of withstanding temperatures higher than 870°C.

Is Toughened Glass Fire-Rated?

Standard toughened glass is not manufactured to withstand the high temperatures required to resist the thermal shock produced in a fire. Toughened glass should not be used in any location where fire-resistant glazing is needed.

How does fire-rated glazing work?

Natralight uses a transparent fire-rated glass to ensure our systems are aesthetically cohesive with other products. Our fire-rated glazing is manufactured from layers of toughened glass interspersed by intumescent layers.

When a fire occurs, the heat from the fire causes the outer layer of the glass to break but the broken pane is held in place by the intumescent layer. These layers rapidly swell which provides insulation that reduces the level of heat from the fire radiating into surrounding rooms. This also helps to prevent smoke from travelling through the opening and into the protected fire exit routes. Some fire-rated glass’ intumescent layer will turn opaque in the heat of a fire that stops vision through the glass. In turn, this can help to reduce the level of panic when exiting the building.

Considerations When Specifying Fire-Rated Glazing

If you are considering having a fire-rated glazing system installed, both the framing and the glass need to be considered. With fire-rated glass, you cannot deviate away from the test evidence plus what has been certified. You will need to pay strict attention to fire rating classifications, as this is the test evidence which demonstrates the ability of each system.

Fire-rated glazing is categorised by the amount of time it will provide protection for when under the effects of a fire. There are different levels of fire-rated glass, and it is important to be aware of the correct fire rating needed. Building Regulations Part B provides a lot of guidance about where fire-rated systems will be required. Fire-rating requirements depend on the exit routes available for occupants and the type of building and its purpose (e.g. a school).

How is the fire rating for glass classified?

Fire-rated glass is classified by the amount of time that it provides integrity and insulation. Here is a brief explanation of both categories -

The Integrity Period - The integrity rating of fire-rated glazing is calculated as the amount of time the glass remains in situ in its frame/fixings during a fire. This also encompasses the glass' ability to stop the passage of flames and hot gasses through the glass when exposed to fire from one side.

The Insulation Period - This is the amount of time the glass acts as an effective barrier against the flames, heat and smoke during a fire. When tested, glazing must limit the temperature on the non-fire side of the glazing to anything below an average of 140C or less than 180C in one single position.

These categories are split into the duration of protection the glass provides for Integrity and Insulation. Fire protective levels can be broken down into E classifications that denote its performance. 

E = glass with an integrity only rating

El = glass with an integrity and insulation rating

EW = glass with an integrity rating and a degree of heat resistance.

Got any More Questions? Get in Touch

If you have any more questions about fire-rated glazing, please contact Natralight today.

We offer a wide range of fire-rated flat rooflights for customers all over the country, with bespoke options available on request.

Don’t take our word for it though, why not read some of our Testimonials from just a small selection of our happy customers.