Systems make giant strides in safety
01 January 2003
Structural glazing systems have been making tremendous strides in fire safety and performance, says Les O'May of Wright Style, a British steel glazing specialist.
The means to deal with fire in buildings are becoming ever more sophisticated, from passive fire detection to active systems, such as sprinkler systems.
However, detection and dousing are all very well, up to a point. The important factor that designers and architects have also had to build into the equation is containment - preventing the fire from spreading too far from its point of origin.
Containment is, of course, fine in theory. However, a building can only function as a building - whether home, office or factory - if people can move around it freely, comfortably and safely. That includes doors and windowsÊ- the so-called weak points through which fire and toxic gas can flow.
Well, no. Glass has always been a versatile product which designers have relied on heavily for aesthetics, performance and protection. What has changed, in a series of small, unrelated and, often, under-reported steps, is nothing less than a glass revolution.
Simply, specialist fire-resistant glasses now allow for innovative architectural concepts to become a reality. The glass and glazing technology to take a bold idea from the drawing board and make it happen is now with us.
The fact is that architects are increasingly looking for larger glazed screens and doors to give better aesthetics, as well as more comfort for the occupants who use them. The glass industry has, using modern technologies, responded - meeting the requirements of architects and, in many cases, exceeding them.
The advances made in the glazing technology have also been fuelled by increasingly stringent building regulations that aim to stop the spread of fire and to enable a safe evacuation of the building. The safety of occupants and fire-fighters alike is of paramount importance.
The requirements of building regulations are that buildings should be subdivided into what are called 'fire compartments.' The objective is to limit the size of the fire that can develop by imposing horizontal and vertical boundaries.
The other aspect of modern building regulation is that there must be adequate means of escape in the event of fire. To ensure this, escape corridors and stairways need to be properly protected.
To fulfil these requirements, fire-resistant glazing systems are developed, tested and approved by exposing the element to a simulated fire, by means of special furnaces.
From commencement of the test, the furnace temperature is raised to in excess of 500 deg C within five minutes, to 1,000 deg C at 120 minutes. The two performance requirements are 'integrity' or 'integrity and insulation.'
Integrity is the ability of a separating element to remain solid, thereby preventing the passage of flame or hot gases. Integrity also relates to the ability of a load-bearing element to remain stable - in other words, to resist collapse.
Insulation is the ability of the separating element to resist heat conduction from the fire-side to the non fire-side, ensuring that intense heat cannot pass though the element and set fire to material on the safe side.
What's important in the design process is to recognise that, while it's the expanse of glass that the designer is looking for, the safety of the glass can't be assessed without its framing system. Put the right glass into the wrong frame, and you could be turning 60 minutes of fire-resistance into five minutes. In an evacuation situation where seconds count, getting the design wrong at the outset could be a costly - and deadly - mistake.
There are many types of fire-resistant glasses currently on the market - and the ranges of products and sizes will continue to increase as the technology for combining glass and glazing systems develops. We have come a long way in the past 10 years to meet the evolving design requirements of architects and the increasing stringency of building regulations. Simply, the new glass and framing technologies mean that the impossible is now possible.
Wright Style has been at the forefront of making architectural aspirations into built reality - and my message to designers and specifiers is to continue to challenge the glazing industry. Glass and glazing systems have come such a long way in so short a time that what couldn't be done even a couple of years ago may now be eminently feasible.
Let me give some examples. Until recently, the concept of a fire-rated opening pivot window was thought impossible. But Wright Style was approached two years ago by architects building a prestigious transit hotel at Dubai International Airport to do just that. The result? Opening fire windows are now in place in the hotel.
Likewise, fire rated automatic doors. Another impossibility, or so conventional wisdom went. However, Wright Style designed, extensively and successfully tested a door set that would function in a fire situation. The first installation recently took place in Hong Kong.
Blast resistance? We can now design and build glazing systems to withstand blast forces hitherto undreamed of. Post 9/11, designers don't have to build new structures with lots of reinforced concrete. For most applications, even the most sensitive, glass remains not only the most aesthetically-pleasing option - but can also be the safest.
My guess is that architects and designers often don't fully understand the huge advances in both glass and glazing systems and how our industry could greatly influence their thinking in the design process. Not their fault - simply that developments have come so thick and fast that communicating those advances has lagged behind.
The eloquence of a modern building lies in the subtle balance between form and function and how the imagination of the design team is translated from computer screen to bricks and mortar.
Architects and designers should think of glass not only as an aesthetic medium but as a means of taking imagination off the drawing board - even in the most sensitive or difficult applications where fire or blast safety is paramount. Then challenge the glass and glazing industry to make it happen.
As far as modern glass and glazing systems is concerned, almost nothing is impossible.
