A good staircase should provide an easy, quick and secure means of communication between the different floors of the building. Below are general requirements for good stairs.
It should preferably be located centrally, ensuring adequate lighting and ventilation.
2. width of ladder
The width of the stairs should be 1.8 m for public buildings and 0.9 m for residential buildings.
The flight of stairs should be limited to a maximum of 12 steps and a minimum of 3 steps.
4. stair pitch
The pitch of long stairs should be flattened by introducing landings. The slope should not exceed 400 and should not be less than 250.
5. head room
The distance between the flight run and the soffit immediately above this should not be less than 2.1 to 2.3 m. Such a height is maintained so that a tall person can use the stairs with some luggage on his head.
Stairs should be constructed using fire resistant materials. The material must also have sufficient strength to resist any impact.
7. witness box
All open well stairs should have balustrades to avoid accidents. In case of wide stairs, railings should be provided on both sides.
The width of the landing should not be less than the width of the ladder.
These should be avoided and can be provided at the low end of the flight if necessary.
10. phase ratio
The going and the rise of a step should be well proportioned to ensure a comfortable access to the stairway.
The following empirical rules can be followed.
- Trades/Going cm + 2 (increase in cm) = 60
- Trades/going in cm x (increase in cm) = 400 to 450 approx.
- Trades/goings in cm + (increase in cm) = 40 to 45 approx.
- Standard size: 30 cm tread, 14 cm . Rise
Other combinations of rise and go can be calculated by subtracting 20 mm from let and adding 10 mm to increment. Thus other combinations of rise and go would be
- Rise 15 cm x 28 cm. go on
- Rise 16cm x Tread 26cm
- Rise 17cm x Tread 24cm
The sizes of the steps generally adopted are:
- Public buildings: (27 cm x 15 cm) to (30 x 14 cm)
- Residential Building: 25cm x 16cm