Fire rated glass and its impact on architecture and building design

Fire-rated glass and glazing has been an indispensable safety component within the built environment for decades. It’s used in both interior and exterior applications to help contain the spread of fire, and can be installed in doors, walls, windows, and even floors; it’s often found in corridors, stairwells, lobbies, courtyards, and wall partitions.

But today’s fire-rated glass certainly isn’t the same institutional-looking wire mesh of yesterday.

Indeed, modern fire-rated glass has evolved significantly from traditional and relatively unsafe wired fire safety glass. New types of fire-rated glazing products – including insulating glass units (IGUs), glass ceramics, intumescent glass, and fire-rated steel framing systems – can withstand impacts, provide acoustic insulation, and even contribute to LEED certification in the categories of energy & atmosphere and materials & resources.

But perhaps most refreshingly, modern fire-rated glazing can now also make a positive contribution to interior and exterior aesthetics – allowing designers to create open, bright, welcoming spaces in areas that also need fire protection.

There are two main types of fire-rated glazing: fire-protective glass and fire-resistant glass:

· Fire-protective glass is designed to retard the spread of smoke and flames from one building compartment to another

· Fire-resistant glass protects further by blocking conductive and radiant heat, and is subject to more stringent testing standards. 

Which type of fire-rated glazing is used typically depends on job requirements and applicable building codes, including the International Building Code (IBC), which governs fire-resistant glass applications in the U.S.

While standard window glass typically breaks at around 250 degrees Fahrenheit, modern fire-rated glass can live through temperatures exceeding 1,600 degrees Fahrenheit. Fire ratings for glass typically reflect the time increment the product can withstand a fire according to testing – so if the glass has a 20-minute fire rating, that means it can withstand fire for 20 minutes.

What types of fire-rated glass are there?

Fire-rated glass has come a long way since the days of mandated mesh wire glass. Formerly a building code requirement, revisions to the IBC in 2003 and 2006 removed the need for wire mesh glass in all types of building construction. That, in turn, opened the door for architects and building materials specifiers to begin incorporating new types of fire-rated glazing systems in their designs.

Relatively new types of fire-rated glazing systems now being used in construction include:

IGUs

Fire-rated insulating glass units include fire-protective or resistant glass and framing systems that do much more than stop or slow the spread of fire. Modern IGUs can be custom built to suit any exterior or interior application, and help conserve energy by reducing solar heat gain, improve acoustic control, and improve natural daylight within a space.

When fire-rated IGUs are outfitted with cordless louvers between hermetically sealed glass, they also provide a completely adjustable privacy and visibility solution requiring no maintenance. IGUs can be outfitted with modern fire-rated glass including glass-ceramics or intumescents.

Glass Ceramics

Also known as ceramic glass, glass-ceramics can withstand sudden and repeated temperature changes up to 1,000 degrees Celsius, allowing it to be used in glazing systems with fire ratings of up to three hours in some cases. Ceramic glass is made by crystallizing a normal glass pane through a treatment of intense heat. It’s relatively versatile, being used in both windows and doors as well as glass cooktops or fireplaces.

The downside to many glass-ceramic products, however, is that they do not block radiant and conductive heat.

Intumescent glass

This is laminated glass composed of multiple, alternative layers of glass and clear intumescent sheets. Like glass-ceramics, it can also be fire rated up to three hours. Intumescent glassworks by allowing the outer glass layer to shatter during a fire, with the inner intumescent layers then expanding with the heat to provide a strong barrier to smoke, flames, and radiant/conductive heat.