What to consider when specifying fire rated glazing for high rise buildings

Every major city is filled with high-rise buildings. A high-rise building is a building with an occupied floor level that’s above 23 metres (usually more than 7 storeys). These structures get more and more impressive as modern architecture and construction systems develop. Not only is the view of high-rise buildings impressive from street level, but they also offer breath-taking views that can be enjoyed from sky decks at the top of elevators.

High-rise buildings are well regulated, planned and constructed. Due to the large number of occupants that these buildings can contain, fire-rated glazing in high-rise buildings is one of the most important building safety requirements that architects and main contractors need to consider. Fire-rated glazing can be used throughout these buildings from the corridors, elevator lobbies and stairwells.

Modern fire-rated glass technology makes it possible for architects to use glazing in more innovative ways than ever before. Imagine how architects used to have to sacrifice clear glass installations for wired glass panes, as this used to be the only type of fire rated glazing available. Architects now have more freedom when it comes to creating minimalistic glazing installations that boast impressive levels of fire resistance. Fire-rated glazing provides effective protection from dangerous radiant heat, smoke and flames, and allows the occupants of high-rise buildings to exit safety in the event of a fire.

Fire rated glass can be used both internally and externally in high-rise buildings, but to take full advantage of its benefits it’s important to understand the different types of products and what the different fire ratings mean.

What are the fire-rated glass classifications?

Fire-rated glazing is manufactured in various different ways depending on the performance and properties that are required. There are three classifications for fire-rated glazing which are: integrity (E), radiation control and partial insulation (EW), and integrity and insulation (EI).

Integrity (E)

This is classed as the most basic form of fire-resistant glass, as when it’s exposed to a fire it prevents flames from travelling through and into the unexposed side of the glass. Although it stops the flames and hot gases from passing through, it doesn’t stop heat from penetrating through the glass.

There are a few methods to create integrity glass. Firstly, there’s the traditional method of embedding wire into float glass while it’s still molten glass. Secondly, there’s modified toughened glass whereby a single pane of glass undergoes a toughening process which modifies the structure of the glass which makes it stronger. And thirdly, there’s the lamination method where two or more sheets of glass are fused together to result in a laminated integrity glass.

Heat control and partial insulation (EW)

This classification is similar to E whereby is prevents flames and hot gases from travelling from room to room, but it also stops some heat from permeating through. The reason why EW rated glass has this additional property is thanks to the way its interlayers react to fire.

EW rated glass can be manufactured by either applying a coating to toughened glass, a lamination process or by including a gel filling between the layers of glass. The coating to toughened glass is applied to the outer pane which reflects heat, which is how this glass specification can help to reduce the amount of radiant heat from passing through the glass. The lamination process sees two or more layers of glass with an intumescent layer between each layer, and the gel-filled glass is similar to the lamination process, but the gel inserted between the layers is fire-resistant.

Integrity and insulation (EI)

This classification is the highest performing fire rated glass specification that prevents flames from passing through and maintains a safe temperature on the unexposed side of the glass. There are two main methods for manufacturing this type of fire rated glass. The first method is where multiple layers of float glass and silicate interlayers are fused together, and if the glass is intended for external use then a Polyvinyl Butyral (PVB) interlayer is included to stop UV rays from reacting with the silicate layers. The other method is where two or more panes of toughened glass and a fire-resistant gel interlayer are sandwiched together and a spacer is installed that runs the whole perimeter of the glass. This is an edge seal capping to stop any leakage of the gel.

These classifications come with performance ratings of 30 minutes, 60 minutes or 90 minutes (e.g. EI30 would be rated for 30 minutes).

Where are fire doors required in high rise buildings?

Fire rated door

Approved Document B of the Buildings Regulations for England and Wales outlines the fire safety requirements for high rise buildings. The level of fire safety and location of fire doors is greatly determined by the floorplan, construction type and occupancy. It’s important to consider the use of each space carefully to determine whether these spaces need a fire door, for example: exit passageway walls, exit staircases, corridor walls and apartment doors.

Building Regulations also states the minimum fire safety classifications (E, EW, EI) and how long these systems need to maintain their fire-resisting performance. In high-rise buildings many fire-resistant glass installations that are installed to protect main escape routes (for example, common escape routes and staircases with a protected shaft). These areas of glazing typically require an EI classification to protect against the spread of flames and smoke while also protecting the escape route from reaching high temperatures.

Fire rated glazing with an EI rating is typically constructed from multiple layers of glass that has an intumescent interlayer. During a fire this interlayer turns opaque and expands which obscures vision of the fire and helps to keep the non-exposed side relatively cool. The intumescent layer turning opaque helps to keeps occupants relatively calm as if they could see through the glass and see the fire, there’s a high chance they may panic.

Understanding the fire rated glazing available from IQ

IQ offers a complete range of fire rated glass solutions and provides the design of the system all the way through to manufacture and installation. Fire rated glazing can be integrated within highly contemporary architectural designs that blend seamlessly into the modern aspects of the design. There are so many options available to work with your designs, including steel framed fired rated walls and doors, frameless effect fire rated doors, fire rated glass floors and frameless effect fire rated glass walls.

Here’s some information about some of the most popular fire rated systems available from IQ for commercial buildings:

Fire rated glass floors

Glass floors are a highly technical glazing product that can require a fire rating if they are installed within exit routes to prevent fires from spreading from one floor to another. Walk on glass floors can be desirable as they allow abundant light to pass through the floor with minimal obstruction. These fire-rated glass floors can achieve a fire rating up to 60 minutes integrity and 60 minutes insulation.

When specifying fire rated glass floors, it’s important to remember that it isn’t just the glass that needs to have fire-resistant properties, it’s all the elements of the construction. For large floor installations, IQ can design an entire fire-rated glass floor assembly with fire-rated steel supports.

Steel framed fire rated walls/ facades

The steel-framed fire-rated walls from IQ are manufactured using specialist steel profiles that are fire-rated and have been fully tested. This system is designed for robust fire protection while offering a chic Bauhaus inspired aesthetic. The steel frames and glazing bars help to add fire safety features, as they help improve the efficiency of the systems by ensuring the glass is held in place in the case of a fire. The steel combined with the fire-resistant glass creates an exceptionally strong barrier if a fire were to occur.

To speak to the team at IQ Projects about the glazing for a high-rise project that you’re working on, just call us on 01494 722 880 or email hello@iqprojectsuk.com

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