The LWF Blog
Fire Engineering Design and Risk Assessment – Sprinklers & Fire Engineering – Part 10August 31, 2017 1:55 pm
In this Fire Engineering Design and Risk Assessment blog series for architects and others in the business of building design, we have recently been discussing Fire Suppression. Sprinklers, of course, are a commonly used tool for fire suppression and in Part 9 we talked about the design codes covering sprinkler installation and how in the main this has not been extended to the use of sprinklers for additional fire protection of areas of glass or exterior walls. In Part 10, we’ll continue from that point, looking at other sources of information and guidance.
While guidance is sparse, particularly in the UK, on the use of sprinklers to protect areas of glass in a fire situation, it is a proven method and has undergone trials to test its effectiveness as far back as 1990, with the notable study by Dr. A.K. Kim and Dr. G.D. Lougheed “Fire Protection of Windows using Sprinklers” published in 1997.
Following the study, a sprinkler system which was specifically designed for use on windows was developed, which was capable of achieving a fire resistance of 60 to 120 minutes. As was mentioned in Part 9, a sprinkler protected windows can still fail if the fail temperature is reached before the sprinkler has begun wetting the glass. A fire which ignites close to the window can cause such a failure. Additional protection can be employed to guard against such instances and one such method is the installation of a 900mm high spandrel panel. The panel gives protection during the early stages of the fire’s growth which allows the sprinklers to react before the glass reaches the fail temperature. This is assuming the fire is based at floor level.
The glass used with such a system must be tempered or heat-strengthened and vertically unobstructed, by mullions for example. It is not practical to use window sprinkler systems on openable windows as it is only suitable for fixed glazing. The glass panel should be sheer, or if there is a join in the glass, it must be butt-jointed.
The Australian Standard, AS 2118.2-2010 – Automatic fire sprinkler systems – Drencher systems gives its scope as This Standard sets out requirements for the design, installation and commissioning of drencher systems intended to provide automatic external protection to windows, doors and other openings from exposure to fire. Such systems must be automatically operated via either sealed or open sprinklers, the water is released upon detection of the fire.
In Part 11 of this series, we will look at the various rules, standards and design codes affecting the use of sprinklers as part of a fire safety design. In the meantime, if you have any questions about this blog, or wish to discuss your own project with one of our fire engineers, please contact us.
Lawrence Webster Forrest has been working with their clients for over 25 years to produce innovative and exciting building projects. If you would like further information on how LWF and fire strategies could assist you, please contact Peter Gyere on 020 8668 8663.