Combined treatment

The Manchester Joint Hospitals project is one of the most ambitious healthcare developments in the UK. Cramped wards and long distances between departments will soon be confined to the annals of history, as four of the oldest hospitals in Manchester are redeveloped on one site in a £420 million PFI project. The development brings together Manchester Royal Infirmary, St Mary’s Hospital for Women & Children, Manchester Royal Eye Hospital and Royal Manchester Children’s Hospital into a new main hospital building.

Construction started in 2004 and is being phased over several years with final completion due at the end of 2009. The PFI package was won by Catalyst Healthcare, the specialist consortium set up by Bovis Lend Lease to bid for PFI hospital projects. The international team of architects is led by Anshen Allen with Mott MacDonald acting as structural and civil engineering advisors and DSSR as consulting engineer for the building services. Balfour Kilpatrick is carrying out the bulk of the electrical services installation whilst its sister company, Lounsdale Electric, is designing, supplying and installing hv/lv substations, hv switchboards and lv section boards.

The poor fabric of the old buildings meant high maintenance and running costs. The new hospitals, with a combined total of 1460 beds, will provide patients with the most up-to-date facilities and high-techequipment all on one site.

Peter Mount, Chairman of Central Manchester & Manchester Children's University Hospitals NHS Trust, says: “Many of the buildings used by the Trust are over 100 years old. They cost £2.5 million each year to maintain and were designed for models of care we would find unacceptable these days. We need more space for families, for medical equipment and for tvs, and all the things that lessen the stress of a stay in hospital.”

Power lines

To give an idea of the scale of the project, 1 300 000 metres of cable will be laid internally. With the huge amount of power and data cabling required in a modern state-of-the-art hospital, the specification of the cable support infrastructure was crucial. Consultant DSSR was concerned to ensure there was no possibility of interference from power lines corrupting the sensitive electronic data flowing through the data cabling. This led to the selection of wire cable trays for use in the cable management.

Paul-Edouard Courson, managing director of Cablofil UK, takes up the story. “Cablofil was not originally specified. It was going to be a traditional tray and trunking. Electromagnetic compatibility (EMC) test compliance became an issue but this was solved with the use of Cablofil wire trays.”

Electromagnetic compatibility

EMC is an ever-increasing factor in the design of modern buildings and it is particularly critical with hospitals which depend on reliable telecoms, IT networks and building services. Interference can also be caused by external sources such as lightning and mobile phones. Good design practice will ensure that measures such as the use of wire mesh trays and cable segregation are put in place to guarantee compatibility and minimise the risk from extraneous interference.

As always, there have been time pressures and the use of prefabricated services modules containing the Cablofil trays has been beneficial

Electromagnetic disturbance is emitted by a source polluting a victim and the transmission of that disturbance is known as coupling. A problem only occurs when the three elements – source, coupling and victim – are evident. To obtain good EMC it is necessary to eliminate one of the elements or reduce its effect.

A metallic cable tray has excellent electrical continuity and is part of the equipotential earth network of the installation. It will reduce the impact of the coupling, thereby participating in good EMC of the electrical installation. Unlike standard steel cable trays, steel wire mesh trays provide protection against extraneous electromagnetic interference by utilising the Faraday cage effect.

Wire mesh trays also have an advantage over conventional trays as cables can emerge from any direction. Routing cables through the mesh rather than over the flange of the tray avoids possible damage to the cable sheath.

Prefabrication

Cablofil supplied the wire mesh cable trays as part of the prefabricated services modules. The modules include 2D flat frame systems and the deeper 3D units six metres long and with a cross-section measuring two metres by two metres. Cables served include the fire protection system, telecoms, extra low voltage (ELV) and trunking. Over 30 km of Cablofil cable trays is scheduled for the services modules for the project.

Prefabrication enables a higher level of quality control than is usually possible on site. The modules are assembled in factory controlled conditions and then delivered to site using purpose built transport jigs which significantly reduces traditional on-site build time.

Stuart Campbell, Balfour Kilpatrick’s project director, comments: “This has been an interesting project, particularly with the innovative building design that is fitting four hospitals into one site. As always, there have been time pressures and the use of prefabricated services modules containing the Cablofil cable trays has been beneficial. The wire trays make for easier installation and give better visibility for locating cables than is possible using conventional trays.”

For more information circle the appropriate number on the Enquiry card or see www.emconline.co.uk/enquiries: Cablofil 175