Glass has become increasingly popular in both commercial and domestic building. It is versatile, aesthetically pleasing, allows light to flow from one room to another, provides sound privacy without losing transparency and more.
Above: A fire-rated glass screen and doors.
Technology and manufacturing processes have greatly improved in the glass industry. Fire-rated glass systems can provide improved levels of protection against fires, without losing their aesthetic appeal and support design needs.
For this glass type to serve its primary function, it must be correctly specified, placed and installed following building regulations. In this article, we briefly look at what fire-rated glass is, how fire resistance is measured in glass, where it must be used, and what you should consider.
What is fire-resistant glass?
Fire-resistant glass or fire-rated glass is a specially made and tested glass used to prevent the spread of fire and hot gasses or smoke. It helps ensure people can safely evacuate from a building in case of a fire and that firefighters can access the location.
Fire-rated glass can withstand temperatures above 870°C. It's different to standard or ordinary safety glass which usually can withstand temperatures up to around 260°C. Float glass (or annealed glass) can only withstand temperatures around 121°C. To find out more about toughened and float glass, see our blog post "What is the difference between Float Glass, Toughened Glass and Laminate Glass?".
Fire-resistant glass is available in many forms such as wired glass, glass ceramics, laminated or toughened. This glass can also be impact resistant and manufactured with acoustic insulation properties. It's versatile too. It can be used internally, externally, on fire-resistant doors, on vision panels, partitioning screens, single glaze or as part of an insulated glass unit.
How is fire resistance in glass measured or rated?
For glass to have a fire-resistance rating, it needs to be tested. This is done in a controlled environment with the glass and framing exposed on one side to a furnace designed to mimic a fire scenario. Generally, the three categories looked at when rating fire-resistant glass systems are integrity, radiation control and insulation.
Integrity (class "E")
Integrity is the ability of the fire-resistant glass screen to prevent the passage of flames and smoke or hot gasses when it's exposed to a fire on one side. This is the most basic class or type of fire-rated glass; it does not stop heat transfer.
Radiation control (class "EW")
Integrity and radiation control is the ability of the fire-resistant glass screen to prevent the passage of flames, smoke and to limit the level of heat transfer. Radiation control also helps slow down the time in which combustible items on the side without the fire start smoking or ignite as a result of heat transfer.
Insulation (class "EI")
Integrity and insulation is the ability of the fire-resistant glass screen to prevent the passage of flames, smoke and to block heat transfer. It keeps the average temperature on the unexposed side of the screen to no more than 140°C. This type of glass offers the highest protection giving people a better chance to evacuate safely.
Above: Glass and frame fire-resistance testing.
Among other things, such as surface temperatures, ratings are measured in time periods usually upward of 30 minutes. For example, a fire-rated glass panel with a rating of E60 ("E" represents integrity) means it would have an integrity period of 60 minutes. Alternatively, a glass panel with a rating of EI 30/30 would mean that glass has been tested and will provide a 30-minute integrity ("E") period and a 30-minute insulation ("I") period.
Remember: Fire-rated glass should only be used as part of an approved fire-rated glazing system and installation method. All parts of the glazing system (glass, frames, gaskets, etc.) and installation method must meet the required performance.
Where must fire-rated glass be used?
The primary function of fire-rated glass is to prevent the spread of fire and smoke, allowing for a safe evacuation and facilitating firefighters entry to a building. Fire-resistant glass is required where fire protection is of utmost importance, usually in common areas, escape routes and staircases.
Building Regulations show where and what type of fire-resistant barriers are required. Not all glass doors and partitions need to be fire-resistant. However, it is essential to know where these are necessary for a building. National documents, such as the Approved Document B for England and Wales, show how to meet Building Regulations, where fire-resistant barriers are required, as well as the integrity and insulation periods. These must be followed to make sure a building is fire safe.
Remember, all parts (including glass, frames, gaskets, seals, etc.) of a specified fire-rated glazing system must be appropriately approved and tested, and correct installation methods must be used to meet Building Regulations. A fire-resistant partition system is only as effective as its' weakest part and installation methods used. It's vital you use an approved fire-rated glazing system correctly, and it is installed by specialists to ensure it serves its purpose in the event of a fire.
Above: A fire-rated glass screen and door used in exits.
What should be considered?
When specifying and installing fire-resistant glass screens and doors, there are several things to consider; we have listed some of these considerations below. This is by no means an exhaustive list.
Know where the fire doors and screens must be used to meet Building Regulations and what type of fire-resistance performance and rating is required
Check if fire doors and screens are for external or internal application and suitable for such
Ensure that the glass and all components of the specified glazing system have been appropriately tested
Consider other safety and security requirements, for example impact resistance
Ensure the correct installation method and fixing details of specified glazing system has been followed
Consider other functional needs, such as acoustics
Ensure the system supports the design and aesthetic needs, including frame type, colours and finish
It's is essential to understand that fire-rated glazing systems, are different from other types of glass glazing systems. They have a vital function to play in building safety. Building Regulations must be followed at all times to ensure these systems have the right level of fire protection, are correctly placed and installed.
Each job is unique and will have its own complexities. We always recommend using qualified, experienced fitters to install your partitioning project. At Prism Glass, we have over ten years of experience in the glass partitioning industry and have installed numerous fire rated glass projects.
If you need assistance with your glass installation projects, estimates, measuring, supply or fitting, we are here to help. You can call us on +44 (0)208 947 8428 (office hours are Monday to Friday 9 am to 5 pm), or write to us via our contact page.
About the author:
Paulo Ferreira is a guest writer. He has extensive experience in project management, marketing and design. He worked for Prism Glass for nearly two years, managing glass installation projects and day to day operations.