Conway under the medway

Conway Security Products have supplied their external camera housings to the Medway Tunnel under the River Medway between Strood and Chatham in Kent, England.

The enclosures are Conway's stainless steel EH4 unit and are being used with two separate sets of cameras which address both regular CCTV surveillance and VAID (Video Automatic Incident Detection). The housings are being used to protect analogue PTZ cameras from the Bosch MIC series used with VIP-X encoders, and IP cameras from Bosch's Dinion range. They form part of a major overhaul of surveillance, SCADA and public address & voice alarm (PAVA) systems at the tunnel. The VAID solution is from Belgium-based Traficon.

The Conway housing, which is manufactured to weatherproof level IP66, is usually produced in 304-grade stainless steel but for this project 316 grade has been used to give camera and lens assemblies maximum protection from fumes and other contaminants as well as reducing the risk of corrosion. The specification also meets the requirements of Department for Transport standard BD 78/99.

Chris Newman, Managing Director of Conway Security Products, said: "The goal of everybody involved with the CCTV project has been to optimise management views for the tunnel operators so they can keep traffic flowing, respond to incidents in a timely, informed manner and safeguard drivers. " He continued: "All of Conway's units are manufactured in their entirety at the company's headquarters in Buckinghamshire, England. This made it possible to provide a tailor-made solution including dedicated bracketry within short lead times which was a major benefit for the integrator, Ematics. The design of our mounting bracket enabled Ematics to minimise camera vibration and also optimised cable management options for their operatives who are working in confined spaces with a graduated luminaire system."

The combination of EH4/ss housing in non-standard steel with special mounts designed by Conway has become a widely-used solution in VAID tunnel management systems. Other tunnel projects adopting this approach include the £260m New Tyne Crossing in the north-east of England, the Hatfield Tunnel in Hertfordshire, the £600m Dublin Port Tunnel and a mountain tunnel in east-central China. The Conway EH4 excels in coastal and river environments where ingress of water and salt are a threat.

The Medway Tunnel was the first immersed tube tunnel to be built in England. It is twin-bore and therefore avoids contra-flow which has been outlawed by the EC. Construction work was started in 1992 and the tunnel was opened by the Princess Royal in 1996. The systems overhaul described here has been performed by Vital Services Group reporting to Medway Council's project manager, Serco.