Section 74(3) in The Greater Noida Industrial Development Area Building Regulations, 1992
(3)Stairways. - (a) Interior stairs shall be constructed of non-combustible materials throughout in case of all buildings except residential buildings up to three storeys in height.(b)Interior staircase shall be constructed as a self-contained unit with at least one side adjacent to an external wall and shall be completely closed in case of all buildings, except residential buildings up to three storeys in height.(c)A staircase shall not be arranged around a lift shaft unless the latter is entirely enclosed by a fire resistance material.(d)The minimum width of an internal staircase shall be 1.00 mtr., except in case of residential buildings including group housing where minimum width shall be 0.90 mtr.(e)The minimum width of treads without nosing shall be 0.25 mtr. for an internal staircase of residential building of any size, and industrial building constructed on plots up to 600 sq. mtrs. and business/mercantile building constructed on plots up to 150 sq. mtrs. In case of other buildings the minimum width of tread shall be 0.30 mtr.(f)The maximum height of the riser shall be 0.20 mtr. in case of residential building of any size, industrial building constructed on plot up to 600 sq. mtrs. and business/mercantile building constructed on plot upto 150 sq. mtrs. In case of other buildings the maximum riser shall be 0.15 mtr. The number of risers shall be limited to 12 per flight.(g)Handrails shall be provided with minimum height of 0.90 mtr. from the centre of the tread.(h)For buildings more than 24 mtrs. in height access to main staircase shall be gained through at least half-an-hour fire-resisting automatic closing doors placed in the enclosing wall of the staircase. It shall be of swing type door opening direct in the escape route.(i)The exit sign with arrow indicating the way of the escape route shall be provided at a height of 0.50 mtr. from the floor level on the wall and shall be illuminated by electrical light connected to corridor circuits.(j)In case of single staircase it shall terminate at the ground floor level and the access to the basement shall be by way of a separate staircase.(k)In the case of residential buildings and business/mercantile buildings constructed on plots up to 150 sq. mtrs. three windows at the start of the staircase at each floor level will be allowed.(l)The areas of the stairway even if the open type, except where it is 0.60 mtr. projecting out from a wall without riser as a subsidiary control shall be counted towards the covered area.
