Section 49(2)(a) in West Bengal Municipal (Building) Rules, 2007
(a)The following appurtenant structure shall not be included in the height of the building :(i)stair cover not exceeding 2.40 metres in height;(ii)lift machine rooms as per the latest edition of the National Building Code:(iii)roof tanks and their supports, the height of support not exceeding 1.00 metre;(iv)chimneys;(v)parapet walls not exceeding 1.50 metres in height;(vi)ventilating, air conditioning and other service equipments;(vii)height above mid-point between eaves level and ridge-level;(viii)toilet at roof level up to a height of 3.0 mtrs. subject to maximum floor area of 3.00 sq.m.;(ix)garden cover with permeable material not exceeding 3.00 mtrs. in height;(x)equipments for communication such as Microwave Antenna, Towers. Dish Antenna as well as room for installing the said equipments or their support equipments subject to a maximum area of 20 sq. m. and further subject to permission of the same from Municipal Authority.