Above: The Medieval Crypts.
Below: Guildhall's Great Hall. Right: The Gherkin photos supplied by City of London Corporation.
The importance of quality in an ever-changing landscape
W
Fire detection for high value prestige
property in the City P
roviding effective fire detection for the City's commercial properties is a challenge,
with the key issues being aesthetic considerations and monitoring voluminous spaces. The City's historic legacy is still visible in properties such as the Mansion House and Guildhall. Perhaps surprisingly, these irreplaceable historic properties share many of the same challenges as modern constructions to implement effective fire detection.
The amazing creativity of architects worldwide has led to a surge of modern buildings that have quickly gained iconic status. The Gherkin is just one illustration of a high value property with a completely original and unique design. These commercial properties need to not only ensure safety but also project a faultless image for their clients.
It might apear that heritage buildings have little in common with the issues of modern constructions. Surely, a building such as London’s Guildhall, built in 1411, has different considerations?
Many heritage properties must adhere to the demands of their listed status: an unobtrusive system that does not compromise the historic and aesthetic integrity is required. Stone facades and ornate decoration limit the options, as even drill holes are forbidden.
A number of solutions are possible, including recreating original light fittings to provide a discreet home for visual detectors or hiding them in wooden structures. Modern buildings owners share this requirement and want detectors to be unobtrusive. Generally, there are numerous opportunities for cameras to be hidden, such as above the ceiling with a cut out for the camera lens.
The voluminous, often unusual, spaces created by new designs present their own set of challenges The Gherkin, for example, has a lobby that reaches 6.5 metres and has 6 light
22 © CI TY S ECURI TY MAGAZ INE – SUMME R 2015
wells with a depth of 25m. Such spaces can be challenging for fire detection, especially in relation to smoke stratification.
Smoke stratification occurs when air containing smoke particles from the fire source is significantly hotter than the surrounding air, making it less dense and effectively buoyant. This air rises and as it rises it cools. When the building height allows, the smoke's temperature will cool to a point where it no longer is sufficient to displace the air above it and as a result the smoke levels out and hangs in the air.
When smoke stratification occurs the smoke particles never reach ceiling mounted detectors, so any technology that relies upon air sampling will fail to detect the fire. Moreover, air flow behaviour can vary greatly in voluminous areas, and so complex and sometimes unpredictable smoke behaviour must be addressed when selecting any fire detection solution.
The main fire detection solutions for high value properties are Visual Smoke Detection (VSD), Infrared (IR) and Aspirating Smoke Detectors (ASD). ASD has heightened sensitivity and is ideal for giving early warnings, being especially effective for situations where fires are not yet visible or in the very earliest stages.
VSD offers high value property buildings a system that can detect fire at source, without sensors having to be triggered. Using visual monitoring, large voluminous areas can be surveyed, focusing on areas of particular concern if required. The challenges of smoke stratification are significantly reduced. The system works by detecting smoke patterns as well as changes in brightness, contrast, shape, motion, colour matching, content and loss that could indicate the early stages of a fire. Visual verification, on or off site, can determine the response required. The key to a successful solution is not centred on compromise, but on a creative approach balanced with the most effective fire detection solution.
Rob Turner FireVu
www.firevu.com
www. c i t y s e cur i t yma ga z ine . com
hen it comes to securing a business from any type of threat, the most
important factor is that quality security solutions are chosen from reputable suppliers that meet the correct standards for their products and services. This is particularly important within the CCTV sector, where the standards landscape is constantly changing and improving.
Last year saw the UK Government launch its CCTV Code of Practice, providing 12 principles laid out by the Surveillance Camera Commissioner in order to regulate the quality of CCTV cameras under public sector ownership. However, research published by the BSIA in July last year found that only 1 in 70 CCTV cameras in the UK exists under public sector ownership. This means that the Government’s regulation only covers a tiny proportion of CCTV systems and that not all privately owned CCTV cameras will be operating to the standard outlined by the Government. Members of the BSIA, however, are inspected to high quality standards and must adhere to specific Codes of Practice outlined by the Association.
“The importance of encouraging the adoption of best practice among installers while driving standards of system selection, installation and operation is paramount, and the BSIA is proud to lead the way in the development and dissemination of best practice,” comments Simon Adcock, Chairman of the BSIA’s CCTV Section.
In light of recent changes within the CCTV standards landscape, the BSIA has revised its own Code of Practice in order to reflect the latest changes in surveillance camera installation standards, including newly-created IEC and Cenelec standards.
Mark Wherrett, Chairman of the BSIA’s CCTV Technical Group, explains, “The BSIA’s Code of Practice remains the go-to document for all CCTV installers, so we wanted to update it to provide users with a cohesive overview of all of the standards and regulations to which they are required to
adhere.The landscape of CCTV standards is complex and can be difficult to navigate, so this Code of Practice, with associated guidance, is intended to provide a single point of information for installers wishing to provide a quality service compliant to legislative requirements.”
Judith Denny BSIA
www.bsia.co.uk
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