Requirements of a Good Stair
All the requirements of a good stair are given one by one as follows as per ISI recommendation.
The stair should be located in such a place where it can be easily accessed. The stairs should be situated near the main entrance in the case of public buildings. And, in the case of residential buildings, it should be centrally placed and all rooms should have a simple, convenient approach to the stair. A good stair should be well ventilated and lighted.
Width of the stairs
The width of the stair is a very important point while considering a good stair. The width of the stair rely on the situation and the purposes. The minimum width of the stairs is fixed on the basis that two persons can cross each other on the stairs without any difficulties. The width of the stairs should be more in case the number of stair users is likely to be higher.
In public buildings where there is more daily traffic using stairs, the width of stairs should be more. And, in that case, the minimum width of the stair may be 1.37 m to 1.5 m. In case of residential buildings width may be provided on a minimum basis. And, in that case, the minimum width of the stair may be 0.9 m.
Pitch of the Stair
The inclination of the stair should not be less than 25° and should not exceed 40°. Too much inclination requires the introduction of large risers which is dangerous for the users. Old and weak persons may feel it difficult to use such stairs. Too flat slope is also not considered desirable.
The clear distance between the tread and the soffit of the flight, immediately above it, should not be less than 2.14 m.
Lenght of flight
The number of steps in a flight should be minimum 3 and maximum preferably not more than 12. A flight of single-step should never be introduced, anywhere, under any circumstances.
Width of the landing should not be less than width of the stair.
As far as possible, introduction of winders should be avoided. Winders may prove dangerous and also involve extra expenditure in shaping them.
From safety point of view open well stairs should be provided with balustrade on open side of the stair.
When flight of the stair consists of more than three steps, hand rail should be provided to give support to the users of the stair.