Connecting the Tunnel
Draka’s Firetuf Connecta system has been chosen for the extension to the Docklands Light Railway [DLR] from King George V station to the new Woolwich Arsenal station. The decision ensures the integrity of the emergency lighting in the tunnel – which runs as deep as 35 metres under the River Thames – that is the major element of the £180 million, 2.5km extension due for completion in early 2009.
Designed specifically for tunnel lighting and power applications where vital fire safety circuits are required to
continue operation in the event of a fire, Firetuf Connecta also provided Colas Rail, which is undertaking the PFI [Private Finance Initiative] contract, with the additional benefits of speed and ease of installation and cost effectiveness. Draka’s contract called for 8,940 metres of the third-party-approved, Halogenfree 0HLS cable that was supplied in precise predetermined lengths and incorporated 711 factory-fitted moulded
Connecta socket outlets.
During installation in the tunnel, secondary outlets to individual luminaires were taken from the primary Firetuf power cables via moulded Connecta plugs. This ensured the fastest possible cable installation and minimised the site labour requirement. The Firetuf power cable is manufactured to BS 7846:2000 and is tested and approved by LPCB [Loss Prevention Certification Board] and BASEC [British Approvals Service for
Cables]. It complies with BS 6387:1994 and is accredited to maintain circuit integrity under category C, W and Z fire conditions.
Being Halogen-free, Firetuf is a natural choice for tunnels because it burns without producing large amounts of dense smoke and does not emit halogen gases. This compares with standard PVC cables, which are used widely in the construction industry, that under fire conditions emit hydrogen chloride gas.
This has a suffocating odour that is detectable in even very low concentrations. Burning PVC cables also
generate hazardous volumes of debilitating or disorientating smoke that can easily increase the likelihood of panic and make safe evacuation much more difficult to achieve.
Docklands Light Railway is one of Britain’s great transport success stories. Built in 1987, it now carries over 60 million passengers a year and consistently achieves record levels of reliability and passenger satisfaction. It was one of Britain’s first light rail systems and has one of the world’s most advanced automatic train control systems.
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