A low rise building might be described as one where the able bodied do not need a lift to reach their floor, but if one is available they invariably use it. This would imply a building of 3-5 floors. A mid rise building is one where there may be 8-10 floors and the lift becomes essential, in order for occupants to use the building. A high rise building might be one which contains 15-16 floors and maybe equipped with lifts serving two zones. Low, mid and high rise buildings describe the majority of the building stock of the UK.Tall buildings might be defined as those buildings over 30/40 stories high. This height can be related to nature, as the tallest tree ever measured was 132.6 m. Generally, if service can be provided from the access level (main terminal floor) to every floor in the building, this is a tall building.A building could be called very tall, once shuttle lifts serving sky lobbies are required. Fortune (1997) defines a tall building as a `skyscraper’, ie: “A high rise building with more than one zone of elevators.” and a very tall building as a `Mega High Rise building’, ie: “A building with one or more sky lobbies and in excess of 75 floors.”.

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.

Download the complete document