Fire-resistant glazing: Getting to grips with regulations

The use of glass is becoming increasingly prevalent in modern building design, particularly across the commercial construction sector, and as this area of the industry forecasts positive signs of growth for the years ahead, we are likely to see demand for high-performing fire-resistant glass increase.

Steve Bond, customer support manager, Fire Protection Glass, at Pilkington United Kingdom Limited, explores how the industry is able to meet increasing demand for next generation products, while complying with stringent Building Regulations for fire safety. Identifying the methods used to test the latest innovations in fire-resistant glazing along the way.

When it comes to today’s built environment, safety is top of the list of priorities for architects and designers. Not only is it of paramount importance that, in the event of a fire, a building’s occupants and the emergency services have a safe exit route, it is just as essential that the spread of the blaze is limited before it causes irreversible damage to the property. With architects now demanding a greater use of glass in their projects, because of its aesthetic and performance properties, fire-resistant glazing is playing an integral role in ensuring our buildings and their occupants are safe and secure.

However, in order to provide an effective level of protection, it is vital that designers and specifiers have a comprehensive understanding of the Building Regulations relating to fire safety, and are able to identify the products required for a variety of applications.

Navigating regulatory requirements

It is Approved Document B within the current Building Regulations that summarises the fundamental fire resistance levels that glass should meet when positioned in different areas of a building.

These regulations are designed to ensure that flames are controlled and contained within the room or space of origin, while also limiting the spread of smoke and fire through fire-resistant compartmentation.

They also stipulate that separating walls or doors must meet specific time periods of fire resistance. Ultimately, this means that it is vital for the fire resistance of any type of glazing used as partitioning to meet these regulations in order to prevent a regulatory breach.

In meeting these requirements, architects and designers are helping to ensure that a building’s occupants have enough time to safely vacate a property should a fire occur, while also maintaining the structural integrity of the property for a reasonable period of time.

Passing the test

The latest developments in fire-resistant glass mean that modern glazing systems installed as curtain walling, internal doors and windows or fire screens can now provide protection against a fire for up to three hours (depending on application).

However, in order to meet the regulations outlined in Approved Document B, it is necessary to look at two functional properties of fire-resistant glass – insulation and integrity.

Insulation measures the ability of the glass to prevent heat transfer from the side of the glass exposed to the flames to the other, while integrity looks at the amount of time glass can prevent fire and smoke from travelling from one space to another.

Classifications for both insulation and integrity are attained by testing glass and glazing systems to a standard time and temperature curve, according to either British Standard BS 476-Part 20-22 or European Standard BS EN 1363. Then, depending on its performance in such tests, each system is classified as having an integrity only, or an integrity and insulation, test time of 30, 60, 90, 120 or 180 minutes.

Feeling the heat

Fire tests are regularly conducted in furnaces specifically designed for this purpose. They are able to heat up to more than 1,100 degrees Centigrade and allow manufacturers to monitor the behaviour of glass under extreme temperature.

For example, when testing Pilkington Pyrostop®, a fully-insulating fire-resistant glass that is made up of glass and special intumescent layers, a number of things occur when the product is exposed to high temperatures, which in turn help to identify three key properties of the glass.

When the glass is heated, the glass pane facing the fire cracks and the first special intumescent layer reacts, foams up and turns opaque. This absorbs the energy of the radiant heat. Secondly, due to the foaming up process, the glass swells, making the unit thicker and providing a better level of insulation. While thirdly the intumescent foam and glass stick together, ensuring the integrity of the glazing.

Investing to meet demand

The continuous research and development activities at Pilkington United Kingdom Limited, and the use of sophisticated testing methods, have resulted in a number of new, innovative products which have recently come to market. These new products provide specifiers with further innovative and reliable glass and glazing solutions, and improve the Pilkington fire-resistant glass range.

Examples include two new Pilkington Pyroclear® Line products, a 30-minute and 60-minute integrity only butt-jointed glazing system. The new system offers floor-to-ceiling fire resistance with integrity performance, using monolithic panes of specially treated and toughened standard soda-lime-silica glass, making them the first of their kind to be used without the need for vertical framing.

Not only does this meet an increasing demand for high-quality fire-resistant products, it also satisfies architects and designers’ demand for enhanced aesthetics. In particular the 30-minute system does not require the use of button fixings between the panes, and as such provides a truly unexpected view.

Continuous evolution

Building regulations and the methods used to test these products will always be at the centre of any future innovations, and as these regulations develop to meet the changing demands of the commercial construction industry it will be vital for those across the industry to keep up-to-date with any pending changes.

For more information, go to www.pilkington.com