Our engineers’ calculations must take into account the variety of occupancy levels, which might span retail, offices, hotel and apartments. Occupancy levels vary significantly between, for example, trading floors and the executive suite, and between high-end apartments and social housing. Designers typically assume 80% capacity for elevator cabins, but this drops to 60% in hotels, where people will have luggage and, intriguingly, in external glass elevators, to give vertigo sufferers more space.
Waiting times must also be factored in, with acceptable times ranging from 25 seconds in offices, to 30-50 seconds in hotels and 45-90 seconds for residential floors, depending on the level of luxury.
Evolving Elevator Technology
VT strategies are evolving rapidly with the increase of super-tall buildings. In such cases, a vertical transportation system of shuttle elevators, where separate banks of lifts serve groups of floors, has traditionally proven to be the most efficient solution from both a passenger and space point of view, creating the need for sky lobbies.
Advances in elevator technology mean that strategies are constantly evolving. Double-decker elevators have increased capacity and triple-decker versions are in development, while “twin” cabins can move independently within the same shaft. There are also technologies that enable energy to be recovered from an elevator’s counterweight and reused elsewhere, while advances in control technology allow passengers to input their destination in the lobby so that the system works out the ideal travel profile for each elevator. The development of super-strength carbon-fiber belts means that a single elevator can now travel over 1,000 metres, where previously steel cables meant the number of floors that an elevator could serve was limited to 100.
The Fastest Elevator in the World
Our high-rise portfolio includes the CTF Financial Centre in Guangzhou that holds a world record for the fastest elevator ever installed. This 530m tower is the city’s tallest building, and includes grade A office space, service apartments, a club and the Rosewood hotel. There will certainly be no waiting around for hotel guests, who will occupy the top 16 floors: the shuttle serving the hotel will climb at 20m per second, twice the speed of the elevator to the observation deck of the Burj Khalifa in Dubai.
In addition to working on other mega-tall projects in China, including Tianjin Goldin Finance 117 Tower, Suzhou Zhongnan Center and Wuhan Greenland Center, WSP is working on other tall buildings around the world such as 22 Bishopsgate and South Quay Plaza in London, Bahria Icon Tower in Karachi and Lotte World Tower in Seoul.