Post 204 –by Gautam Shah
Stairs are stepped and inclined foot-ways. Stairs’ ‘flights’ are point to point passageways, without any side connections (except at landings), so are very efficient transfer systems. Stairs, unlike corridors have no interfering mid-way entrants except at landings. The mid-way disturbance occurs in mountain side and very wide stairs where ‘cross (diagonal) ascent or descent’ occurs to increase the ‘tread depth’ of the steps. Stairs are shortest inclined passages but require some orthopaedic proficiency (capacity of the user to manipulate the legs and bend the body).
Stairs as stepped ways have a pitch not less than 17.30°(5:16), and not more than of 48.30 °(9:8). Below these limits it becomes a ramp or foot-way, and above it a ladder.
- A ladder is not a comfortable tool though some are easier to climb than others. Step-ladders are lower in pitch, less than 75° and require flat treads. Risers may be either ‘open’ or ‘closed’ for toe accommodation. Handrails may or may not be provided. In this classification are ladders, used for fire escapes, boiler rooms, fly galleries, attics, decks, etc. Rung ladders are pitched more steeply, above 75°, and have extremely narrow treads or round rungs to accommodate the foot. In certain cases, the space to accommodate the knee between steps may be necessary.
Rung ladders usually do not require additional handrails as the side members of the ladder can be used for holding grips. Rung ladders are often caged for safety, though such cages are more useful for ascent then for descent. It is safer to climb down facing the ladder. Swimming pools, water tanks, sewers have rung ladders. Manhole steps are very narrow in widths, but the width is otherwise compensated by its staggered placement. The same holds true, for climbers for bunk beds, whether in railways, buses, barracks or homes.
Ziggurats of Urnammu (2125 BC) are one of the oldest examples of ceremonial step ways. Egyptians built ceremonial stairs for a rock-cut temple at Del-el-Bahari (1520 BC). The Cretan palaces (1500 BC) had stairs that moulded the architecture. Greeks and Romans have exploited stepped-architecture for amphi theatres, stadia, thermae (bath houses) where the visual angle, support structure and curvatures in the plan were tackled.
In medieval Indian architecture bathing Ghats, Kunds and step wells had a distinctive element of planning. Kutub minar, Azan Minarets of Mosques, entrance steps for Fatehpur Sikri and Jama Mosque Delhi, show functional use of steps. Observatories, Jantar-Mantar, at Jaipur and Delhi have been articulated with steps.
Romanesque period saw interior stairs and outdoor steps for entrances with converging and diverging flights on a common landing or a foyer. Spiral stair with a column or pier as the central element, often called Newel, were used in Gothic buildings. Later Gothic buildings had large diameter spiral stairs with an open central core. Post Gothic period stairs began to wind in many directions, had variable widths and curved steps. Renaissance stairs were extensively decorative, with balustrades, broad moulded handrails and statuette like newel supports at every start, turn and end. The stairs were not enclosed structures or staircases, but stairways as open structures. Stairs began to visually connect all the floors interim spaces. Stairwells or gaps, created spaces which were multi-layered and yet interconnected. Open or exterior steps became features of landscape design in plazas and gardens, such as in Villa de este at Trivoli, Scala di Spagna at Rome, Capitol at Rome, Kashmir Mughal gardens.
During 19th C new transportation system required for Ports and stations, and stairways became true transfer system for masses. Like stations, the stairways of large stores, auditoriums, assembly halls, served an identical function, of being visible. Stairs have a problem that one has to be conscious of climbing then enjoy the open space around. This was corrected in automated stairways as escalators, and later in open cage or bubble elevators.