Section 51(ii) in The Punjab Capital (Development and Regulation) Building Rules, 1952
(ii)Notwithstanding the provisions of Clause (i) above a chimney shaft shall be built 1.8 M high above the roof in the case of approachable terraces used for sleeping purposes and within the heights of the parapet in other cases. In the case of sloping roofs, the chimney shaft shall not be less than 0.6 M above the ridge of the roof in which it penetrates.
