Requirements for a Good Staircase

Requirements for a Good Staircase

1. Staircase should be so located that they can be easily accessible from the different rooms of the building.
2. It should have provision for adequate light and proper ventilation.
3. It should have sufficient stair width to accommodate a number of persons in peak hours or emergencies. Generally, for interior stairs, the clear width may be required to be at least 50 cm in one and two family dwellings, 90 cm in hotels, motels, apartment and industrial buildings and 1.1 m for other types of occupancy.
4. The number of steps in a flight should generally be restricted to and a minimum of 3.
5. Ample headroom should be provided not only to prevent tall people from injuring their head, but also to give a feeling of spaciousness. Vertical clearance should never be less than 2.15 m.
6. Sizes of risers and treads should generally be proportioned from the comfort point of view. Treads should be 25-325 cm wide, exclusive of nosing. Treads less than 25 cm width should have a nosing Of about 25 cm. The most comfortable height of the riser is 17.5-18.5 cm. Generally, the following formulae should be used:
   410. The product of riser and tread must be between 400 and 410.
   411. Riser plus tread must equal 42.5—43.5 cm.
   412. Sum of the tread and twice the riser must lie between 60 and 64cm.
7. Stair width depends upon the purpose and importance of the building. In the case of residential buildings, it should be kept as 1 m.
8. The number of stairways required should be controlled on the maximum floor area contributory to a stairway. The number of persons that may be served by stairs per floor per 55 cm unit of stair width should be 15 for such buildings as hospitals and nursing homes, 30 for other institutional and residential buildings, 45 for storage buildings, 60 for mercantile, business, educational, industrial buildings, theatre and restaurants, 80 for churches, concert halls and museums, and 320 for stadium and amusement structures.
9. The minimum width of landing should be equal to the width of the stairs.
10. The maximum and minimum pitch should be 40′ and 25′ respectively in any stairs.
11. Winders should be provided at the lower end of the flight, only when it is essential. Generally, the use of winders in a staircase should be avoided.
12. In open-well stairs in order to avoid the danger of accidents balustrade must be provided.
13. The live loads to be considered on stairs have been stipulated by IS:87S—1964. The stairs and landings should be designed for a live load of 300 kg/mi in buildings where there are no possibilities of overcrowding. In the case of public buildings and warehouse, where overcrowding is likely, the live load may be taken as 500 kg/m2.