Categories of stairs

The direct flight is the most popular ceremonial approach, but there are many ways of providing vertical circulation. Figure 2.2 depicts the various categories of stairs and shows the elaboration that can be achieved by adding turned steps or landings. Floor-to-floor heights are not always constant within buildings, and the strategy in adopting landings and return steps often helps to accommodate differing storeys without increasing the basic stairwell. The direct flight or single return version will occupy a greater floor area once the extent of upper landings is taken into account. The popularity of dog-leg or three-turn flights rests with the minimal core dimension required.

Figure 2.1d Direct flight at main entry to the Maison Carrée, Nîmes, 16 bc- the portico

The three- and four-turn arrangements facilitate rotating the axis of approach. They also allow permutations to be made in terms of priority, landing by landing and turn by turn.

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