Stairs connect different horizontal levels in a building and allow people to travel between floors. There are several types of stairs including straight run stairs, quarter turn stairs, half turn stairs, spiral stairs, and circular stairs. Stairs are constructed from various materials like timber, brick, stone, steel, and reinforced concrete with each having advantages and disadvantages in terms of strength, fire resistance, and weight. Key parts of stairs include treads, risers, strings, landings, and handrails.

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2. Staircasewhat is staircase? Stairs are the medium through which a person can travel from one horizontal level to another horizontal level although it connects two different horizontal levels.

3. stairsA stair is a set of steps leading from one floor to the other. It is provided to afford the means of ascent and descent between various floors of the building. The room or enclosure of the building, in which the stair is located, is known as staircase. The opening or space occupied by the stair is known as a stairway. In a domestic building the stairs should be centrally located to provide easy access to all rooms. In public buildings, stairs should be located near the entrance. Stairs may be constructed by timber, bricks, stone, steel or reinforced cement concrete. Staircases provide access and communication between floors in multi-storey buildings, and are a path by which fire can spread from one floor to another. Staircase, therefore, must be enclosed by fire resisting walls, floors, ceiling and doors. It is desirable that the linings to the walls and the ceilings are non- combustible and of low flame spread. Another important aspect in the design of stairs is the strength aspect. It must be designed to carry certain loads, which are similar to those used for the design of floor.

6. Double flight straight stairs

7. Quarter turn newel

8. Half turn newel

9. Open wall stairs

10. Dog legged stairs

11. Bifurcated stairs

12. Circular stairs

14. HALF TURN NEWEL In half turn newel stairs the stairs runs straight and after reaching the landing it turns to left or right and then climbs up to next two to three steps and reaches a landing and these steps again turns in the direction from where the user was approaching reaching finally to the consecutive horizontal level. . OPEN WALL STAIRS These are like normal doglegged stairs but the only difference is that after reaching the landing the stairs ends up with a railing instead of the wall.

15. DOG LEGGED STAIRS Dog legged stairs are the stairs in which the user climbs up to a flight turns at one eighty degree n then climb stairs in opposite direction BIFURCATED STAIRS In bifurcated stairs the stairs runs at a flight an as it reaches the landing the stairs runs from left and right side reaching the same horizontal level these stairs are provided generally in atrium of a building.

16. CIRCULAR STAIRS The stairs made in in a circular form are known as the circular staircase. SPIRAL STAIRS Those stairs which are in spiral form is known as spiral staircase,.

18. The technical terms associated with the design and constructions of stairs are:TREAD: it is the upper horizontal portion of a step upon which the foot is placed while ascending or descending.RISER: it is the vertical portion of a step providing a support to the tread. FLIGHT: this is defined as an unbroken series of steps between landings.LANDING: it is the level platform at the top or bottom of a flight between the floors. A landing facilitates change of direction and provides an opportunity for taking rest during the use of the stair.RISE: it is the vertical distance between two successive tread faces.GOING: it is the horizontal distance between two successive riser faces.STRINGS AND STRINGERS: these are the slopping members which support the steps in a stair. They run along the slope of the stair.NEWEL POST: newel post is a vertical member which is placed at the ends of flights to connect the ends of strings and hand rail.BALUSTER: it is vertical member of wood or metal, supporting the hand rail.HAND RAIL: it is the surrounded or moulded member of wood or metal following generally the contour of the nosing line, and fixed on the top of balusters.

19. STAIRS OF DIFFERENT MATERIALS TIMBER STAIRS: these stairs are light in weight and easy to construct, but they have very poor fire resistance. They are used only for small rise residential buildings. Sometimes, fire resisting hard wood of proper thickness may be used. STONE STAIRS: these are widely used at places where ashlar stone is readily available. Stone stairs are quite strong and rigid, though they are very heavy. Stone used for construction of stairs should be hard, strong and resistant to wear. The simplest form of stone stairs is those supported on both the ends, though an open well stair case can also be built. BRICK STAIRS: these are not very common, except at the entrance. However, brick stairs of single straight flight are often made in village houses. The stairs consist of either solid wall, or also, arched openings may be left for obtaining storage space. METAL STAIRS: stairs of mild steel or cast iron are used only as emergency stairs. They are not common in residential and public buildings, though they are strong and fire resistant. These are commonly used in factories, godowns, workshops, etc. R.C.C: these are the stairs widely used for residential, public and industrial buildings. They are strong, hard wearing and fire resisting. These are usually cast- in – situ and a wide variety of finishes can be used on these.