As a general rule, about 60 floors can be served from a main terminal lobby at ground level, by up to four groups of lifts (a practical limit). If double deck lifts are used, this permits up to 80 floors to be served from a main terminal lobby. Buildings with more than 80 floors require sky lobbies with shuttle lifts to serve them. This permits buildings of 120/160 floors with one sky lobby and buildings of 180/240 floors with two sky lobbies with single/double deck lifts. Remember the maximum practical number of lifts that can be grouped together is eight cars with four facing four.
The Council on Tall Buildings and Urban Habitat survey of the 100 tallest buildings in 1999 (reported in Elevator World, 1999) indicated 63 were in North America, 30 around the rest of the Pacific Rim, four in Europe (one in London) and three others. The heights of the top 50 ranged from 260-450 m, a 190 m range, whilst the bottom 50 ranged from 230-260 m, a 30 m range. There must be hundreds of buildings between 130 m (the highest tree) and 230 m.
Very tall buildings sometimes described as ‘monumental’ buildings are few in number compared to the totality of buildings world wide and their traffic design requires expert consideration. The traffic design of such buildings employs many techniques such as stacked zones, shuttle lifts and sky lobbies, transfer floors, double deck lifts and “top/down” service.