Protecting cities against fire with advanced glazing

Protecting cities against fire with advanced glazing

Featured Article
06 Feb 2019

As Featured in GGP Magazine - 04/18

Steve Bond, customer and technical support manager – fire protection, Pilkington United Kingdom Limited, explains why glass is a key material in preventing fire spreading in dense urban environments. 

Buildings rich in natural light are often in high demand. While installing more glass in properties is the obvious choice to achieve bright, open workspaces and dwellings, the need to protect against the spread of fire can often pose problems for those specifying glass in built-up, urban areas.

Approved Document B (ADB) currently regulates fire safety matters in and around buildings in England. Areas of guidance, include the safe evacuation of people and also prevention of internal as well as external fire spread. Ensuring external envelopes provide sufficient fire resistance is at the heart of this.

With glazing being used more and more on external facades, there is now an even greater onus on the ability of glass to stand up to and prevent the spread of fire. If the safety of buildings and those who use them is to be preserved, it’s essential that glazing design and installation keeps pace with the growing demand for glass as a functional construction component. 

For example, the regulations currently state that the use of standard glazing is classed as an unprotected area of the external wall and therefore this area is limited according to the distance to a neighbouring building. Using fire rated glass can increase the allowed area of glazing, thus brightening the space.

Fire-resistant glazing technology has progressed rapidly in recent years and products new on the market can stand up to fire for extended periods of time. Alongside this, the use of larger pane sizes have been tested and approved for use in settings particularly at risk of fire.

Historically, wired glass was predominantly used as fire-resistant glazing, but today, the majority of fire-resistant glass used is completely transparent. This is made possible by making use of intumescent interlayers, which provide increased integrity and insulation. When heated, the intumescent layers turn opaque and expand to form a barrier to hot gases and flames, as well as insulating from the heat of the fire. It is possible for fire-resistant glass to provide complete protection against heat transfer for up to three hours, depending on its specification and system design. 

A case in point

Fire protection was a key challenge for developer Meritcape when it set out to refurbish 1 Aylesbury Street – a converted historic warehouse building in Clerkenwell, East London.

The designers wanted to fill every floor with natural light, from both the front and the back, by using floor-to-ceiling glazing throughout. However, the rear of the property was just three metres away from a neighbouring building.

Fire spread from the converted building was considered, so the rear façade of the building was glazed in Pilkington Pyroclear® Plus insulating double-glazed units, delivering not only the right level of fire resistance, but also excellent thermal insulation (U-value) properties to reduce heat-loss from the building. 

As well as sealing in flames and smoke for at least an hour, the glass also provides radiation shielding that reduces the amount of heat energy that can pass outwards through the glass – another key means of reducing the spread of fire.

This project demonstrates how by specifying fire-resistant glazing, the developer could install a wall predominantly of glass while still complying with regulations, providing protection against fire and letting natural light flow in.

As the demand for rooms and buildings rich in daylight continues to increase, so will the need for advances in fire-protective glass products and technologies. This, in turn, will see the glass industry’s responsibility for fire safety grow further as it becomes more prominent in buildings, ensuring glass can be used to create stunning properties without compromising fire safety.