Stairs

Stairs give access from floor to floor. The space/room housing stairs is called staircase. Stairs consists of a number of steps arranged in a single flight or more number of flights.

The requirement of good stairs are
(a) Width: 0.9 m in residential buildings and 1.5 m to 2.5 m in public buildings.
(b) Number of Steps in a Flight: Maximum number of steps in a flight should be limited to 12 to 14, while minimum is 3.
(c) Rise:
Rise provided should be uniform. It is normally 150 mm to 175 mm in residential buildings while it is kept between 120 mm to 150 mm in public buildings. However in commercial buildings more rise is provided from the consideration of economic floor area.
(d) Tread:
Horizontal projection of a step in a stair case is called tread. It is also known as going.In residential buildings tread provided is 250 mm while in public buildings it is 270 mm to 300 mm.
The following empirical formula is used to decide rise and tread:
2R + T > 550 mm but < 700 to 600 mm
where R is rise in mm and T is tread in mm.
(e) Head Room: Head room available in the stair case should not be less than 2.1 m.
(f) Hand Rails: Hand rails should be provided at a convenient height of a normal person which is from 850 mm to 900 mm.