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Stairs, staircase, stairway, flight of stairs are all names for a construction to bridge a vertical distance by dividing it into small ones, steps.

Table of contents
1 Usage
2 Components and terminology
3 Measurements
4 Ergonomics and Building Code Requirements
5 Forms
6 Longest Stairway


They are in buildings and used for smaller vertical distances, and as physical exercise, and in the case of emergencies (some stairways, especially on the outside of a building, are only for emergencies, as fire-escape). Stairways may be straight or round, or sometimes consisting of two straight pieces with a corner.

Sometimes there are stairs on a hiking path, avoiding more difficult climbing and also the detour that vehicles have to take.

Stairways are also used to enter and leave some vehicles. They may be a separate object or part of the vehicle, either fixed or foldable/retractable. There are also stairways in double-decker vehicles, and small ones in vehicles with a floor that is not everywhere at the same level.

Stairs are not suitable for wheelchairs and other vehicles. A stairlift is a mechanical device for lifting people and wheelchairs up and down stairs. For sufficiently wide stairs, a rail is mounted to the treads of the stairs. A chair or lifting platform is attached to the rail. A person on the chair or platform is lifted as the chair or plaform moves along the rail. Specialized rails are required for circular stairs or for change in stair directions on a landing. Wheelchairs may require special attachments and wider stairs.

Special stairways are an escalator and a ladder.

Alternatives are an elevator and an inclined moving sidewalk.

In larger and older houses, in addition to the main stairs there may be service stairs. The main stairs would be ornate, and usually opening onto the main foyer. Guests and the home owners would use the main stairs. Household staff would use the service stairs in the back of the house. Service stairs are usually enclosed and utilitarian. They are often steeper than the main stairs. Building code restrictions on the main stairs may not apply to the service stairs. Stairs to attic or basement may also be classified as service stairs for building code purposes.

Components and terminology


The step is composed of the tread and riser.

The railing system

The balustrade is the complete system of railings and pickets that prevents people from falling over the edge:
Handrails may be continuous or post-to-post (or more accurately newel to newel). For continuous handrails on long balconies, there may be multiple newels and tandem caps cover the newels. At corners, there are quarter-turn caps. For post-to-post systems, the newels project above the handrails.

Other terminology


Stair measurements:

Ergonomics and Building Code Requirements

Ergonomically and for safety reasons, stairs have to have certain measurements in order for people to comfortably use them. Building codes will typically specify certain measurements so that the stairs are not too steep or narrow. Building codes will specify
[1]: Jacques Francois Blondel in his 1771 Cours d’architecture [1]was the first known person to establish the ergonomic relationship of tread and riser dimensions[1].


Stairs can take infinite number of forms, combining winders and landings.

The simplest form is the straight flight of stairs, without any winders nor landings. It is not often used in modern homes because:

Most modern stairs incorporate at least one landing. A "L" shaped stairs have one landing and a change in direction by 90 degrees. "U" shaped stairs may employ a single wider landings for a change in direction of 180 degrees, or 2 landings for two changes in direction of 90 degress each. Use of landings and a change of direction have the following advantages: Spiral stairs wind around a central pole. They typically do not have an inner handrail, just the central pole. A squared spiral stair assumes a square stairwell and expands the steps and railing to a square, resulting in asymmetric steps. A pure spiral assumes a circular stairwell and the steps and handrail are regular and symmetric. A tight spiral stair with a central pole is very space efficient in the use of floor area.

Helical or circular stairs do not have a central pole and there is a handrail on the inner side.

Both spiral and helical stairs can be characterized by the number of turns that are made. A "quarter-turn" stair deposits the person facing 90 degrees from the starting orientation. Likewise there are half-turn, three-quarters-turn and full-turn stairs. A continuous spiral may make many turns depending on the height.

Winders may be used in combination with straight stairs to turn the direction of the stairs. This allows for an infinite number of permutations.

Alternating tread stairs

Where there is insufficient space for the full run length of normal stairs, alternating tread stairs may be used. Alternating tread stairs are a recent invention that allows for safe forward-facing descent of very steep stairs. The treads are designed such that they alternate between treads for each foot: one step is wide on the left side; the next step is wide on the right side. There is insufficient space on the narrow portion of the step for the other foot to stand, hence the person must always use the correct foot on the correct step. The slope of alternating tread stairs can be as high as 65% as opposed to standard stairs which are almost always less than 45%. The advantage of alternating tread stairs is that people can descend face forward. The only other alternative in such short spaces would be a ladder which requires backward-facing descent. Clearly alternating tread stairs may not be safe for small children, the elderly or the physically challenged. Building codes typically classify them as ladders and will only allow them were ladders are allowed

Longest Stairway

The longest stairway is listed by Guinness Book of Records as the service stairway for the Niesenbahn funicular railway near Spiez, Switzerland, with 11 674 steps and a height of 1669 metres [1]. The stairs are strictly employee-only.

See also Stairway to Heaven.