A good stair should provide an easy, quick and safe mode of communication between the various floors of the building. General requirements of good stairs are as mentioned below.
It should preferably be located centrally, ensuring sufficient light and ventilation.
2. Width of Stair
The width of stairs for public buildings should be 1.8 m and for residential buildings 0.9 m.
The flight of the stairs should be restricted to a maximum of 12 and minimum of 3 steps.
4. Pitch of Stair
The pitch of long stairs should be made flatter by introducing landing. The slope should not exceed 400 and should not be less than 250.
5. Head Room
The distance between the tread and soffit of the flight immediately above it, should not be less than 2.1 to 2.3 m. This much of height is maintained so that a tall person can use the stairs with some luggage on its head.
Stairs should be constructed using fire resisting materials. Materials also should have sufficient strength to resist any impact.
All open well stairs should be provided with balustrades, to avoid accidents. In case of wide stairs it should be provided with hand rails on both sides.
The width of the landing should not be less than the width of the stair.
These should be avoided and if found necessary, may be provided at lower end of the flight.
10. Step Proportions
The ratio of the going and the rise of a step should be well proportioned to ensure a comfortable access to the stair way.
Following empirical rules may be followed.
Treads/Goings in cm + 2 (rise in cm) = 60
Treads/Goings in cm x (rise in cm) = 400 to 450 appx.
Treads/Goings in cm + (rise in cm) = 40 to 45 appx.
Standard sizes: Tread 30 cm, Rise 14 cm
Other combinations of rise and going can be calculated by subtracting 20 mm from going and adding 10 mm to rise. Thus other combinations of rise and going would be