STAIRS

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

The requirement of good stairs is following:

(1) Width: in residential buildings 0.9 m and in public buildings 1.5 m to 2.5 m

(2) Number of Steps in a Flight: In a flight Maximum number of steps should be limited to 12 to 14, whereas minimum is 3.

(3) Rise: Rise provided should be uniform. Normally it is 150 mm to 175 mm in residential buildings whereas in public buildings it is kept between 120 mm to 150 mm. However more rises is provided from the consideration of economic floor area in commercial buildings.

(4) Tread: in a stair case Horizontal projection of a step is called tread. It is also known as going. Tread provided is 250 mm in residential buildings while in public buildings it is 270 mm to 300 mm.

Following empirical formula is used to determine rise and tread:

2R + T > 550 mm but < 700 to 600 mm where R is rise in mm and T is tread in mm.

(5) Head Room: in the stair case Head room available should not be less than 2.1 m.

(6) Hand Rails: at a convenient height of a normal person Hand rails should be provided which is from 850 mm to 900 mm.