BT Tower, London
COMMISSIONING:
The British Telecom Tower started construction in 1961 and was completed in 1964, costing £2.5 million to construct. It was commissioned by the UK Government for the then General Post Office that was also responsible at that time for the country's growing telecommunications requirements. It was designed by a team of architects at the not-very-sexy-sounding Ministry of Public Buildings and Works led by Eric Bedford. The principal building contractors were Peter Lind & Co.
CONSTRUCTION:
The BT Tower is a 189 metre narrow cylindrical tower of 13,000 tonnes of concrete, steel and glass. The first 16 floors are utility platforms dedicated to radio, ventilation, refrigeration and power units. The power units are integrated providing uninterruptible power supply (UPS) to the building and its telecommunications facilities in the event of a power failure, at which time, the UPS units automatically provide power to the complex until the on-site generators take over the provision of power supply.
Above the 16 utility floors is a 35-metre open section bristling with microwave antennae, aerials and dishes that are the principal purpose of the building providing telecommunications transmissions carrying TV, voice and data via microwave radio.
Above this telecommunications sector are 6 further floors housing the Presentation and Function Suites, kitchens and more technical facilities. Above that are the lift motors and water tanks and crowning it all is a huge lattice weather radar aerial.
Access and egress is provided exclusively by two internal high-speed lifts that travel at 22 km/h.
All windows are specially glazed to allow light intake but heat deflection.
INNOVATION:
The building was required to provide a Central London Telecommunications hub and was designed to optimise provision of those types of services. Although a conventional office block was considered in the early stages, the designers settled on a narrow cylindrical solution that provided the height necessary to enable telecommunications transmissions across the whole of London as well as unhindered physical placement of telecommunications equipment covering a complete 360 degree aspect. The slim vertical dimensions of the building were deliberately engineered to allow no more than 20 cm lateral movement so as not to adversely affect the alignment of the telecommunications equipment. (All tall buildings sway to some degree and have tolerances engineered in their design to accommodate the natural forces that cause such sways.)
Although of no practical value to the building's function, floor 34 revolves at a speed of 0.17 km/h completing a full rotation every 22 minutes. This floor was originally designed as a revolving restaurant offering panoramic views of the whole of London requiring, literally, no effort from the diner.
The building is a highly distinctive, innovative and practical design that effectively combines originality with functional purpose.
