FIRE SAFETY
Are UK cable testing systems fit for purpose?
In an article entitled ‘Are your life safety & firefighting systems fit for purpose’ published in Healthcare Facilities, the journal of The Institute of Healthcare Engineering, Australia, Richard Hosier, regional manager, Asia/Pacific at MICC Group, discussed some of the potential consequences should the electrical wiring systems that connect vital fire safety systems fail during a fire, key measures to take to minimise the chances of such failure, and the prevailing regulations and standards in Australia governing such key criteria as the fire resistance and fire retardance of such cabling. Here he focuses on what he sees as some of the key anomalies in current UK Building Regulations as regards fire testing of such cabling, and highlights the more stringent requirements in force in the US.
Furthermore, buildings of this age were mostly not very tall or very large. Today our built environment is far more complex, and inclusive of small domestic, industrial/commercial buildings, super high-rise, mega-interconnected transportation, retail, and commercial structures with significant below ground environments, and especially healthcare facilities, where large numbers of people have no or limited mobility. Across these building types we have a large range of evacuation times, and where these egress times are very long, designers and engineers need to look for alternative, more innovative, solutions for evacuation or protection of occupants, such as reducing fire loads, lift evacuation, or ‘protect in-place’ refuges.
Today the UK Building Regulations Approved Document B adopts the standard time/temperature protocol of ISO834-1 in BS476 parts 20 to 24 for fire resistance testing of all building elements such as fire doors, fire stopping systems for penetrations, structural elements, fire walls and partitions – in fact every material, component, and product used in a building that is required to have a fire resistance rating. What is often overlooked is that this time/temperature protocol for fire resistance testing (ISO834-1/EN1363-1, aka the standard time temperature curve) was developed almost 100 years ago, when buildings and contents were commonly made of masonry, wood, and fabric. At this time plastics and synthetic materials did not exist.1
HEJ would like to thank the IHEA, the editor of Healthcare Facilities, and the magazine’s publishers, Adbourne Publishing, for facilitating the submission and publication of this article. Thanks are also due to Al Rufaie for his Technical Commentary.
British Standards – small-scale tests for certifying life safety cables
American UL2196 – full-scale tests for certifying life safety cables Unrepresentative installation Unrealistic cable fixings
Unrealistic water test
Large scale at 1020˚C
Vertical and horizontal
Real fireman’s hose
Figure 1: Key differences between British and American standards for certifying life safety cables.
Five profiles above original parameters Recent research2
fire-resistant building elements. (BS476, parts 20-24)
has identified that in ‘‘
most modern buildings the use of lightweight polymeric building materials, plastic contents, synthetic foams, and fabrics, with high calorific values can significantly increase fire loads, resulting in fire profiles significantly different to, and in some cases well above, the original parameters of the existing early 1900s test protocol, as adopted in the UK Building Regulations for testing of
Underground environments can also exhibit very different fire profiles to those in above ground built environments,3 especially in confined underground public areas like road and rail tunnels, underground shopping centres, and car parks where a high fire load is present. Fire temperatures in these areas can exhibit a very fast rise time, and reach temperatures well above those in standard model above ground buildings.
Underground environments can exhibit very different fire profiles to those in above ground built environments,3
especially in confined
underground public areas like road and rail tunnels, underground shopping centres, and car parks
August 2018 Health Estate Journal 27
©MICC
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