Section 144(5) in West Bengal Municipal (Building) Rules, 2007
(5)Every staircase shall be provided with treads of not less than twenty-five centimetres in width and not more than eighteen centimetres in rise without winders with landings of width not less than that of the staircase. The treads and rise of each flight of stairs in such staircase shall be of uniform width and height. (The staircase landing from first floor and above may project from the building line in the wider side space up to a maximum width of 1 metre only.) Clear height of such projected landing above ground level shall be 2.25 m minimum. Similar projection of 1 metre of staircase landing from the building line may also be allowed in the back space for corner plots where no wider side space exists or where the wider side space is reduced to counterbalance the difficulty in planning, but a clear gap of 1.5 metre must always be kept from the property line. Further projection beyond this line will, however, not be allowed in the shape of chajja or in any other form. This projection will, however, not be allowed in back spaces for rectangular plot, nor in the front spaces or in the narrower side spaces of any plot. In the case of buildings other than residential or hazardous building, a staircase shall be provided for every 300 persons who are expected to use the building. No staircase shall be less than 1.5 metre (5 ft) in width and the farthest corner of the building shall not be more than 18 m (60 ft) distant from the staircase. The width of landing at the roof level for all categories of plots shall not be wider than the minimum width of stair flightProvided that lift (as per provisions of rule 63) shall have to be provided for a building beyond 13.5 m height from the Ground Level but the lift machine room will be as per latest edition of the National Building Code. The lift machine room will not be included while calculating floor area.Note : Lift may also be provided in any building other than mentioned above as per norms stated in these rules.
