Section 61(1) in The Tamil Nadu Cinemas (Regulation) Rules, 1957
(1)All staircases shall be constructed entirely of stone, cement or concrete with fire-resisting roof and ceiling and shall have solid square (as distinguished from spandrel) steps and landing of approved stone or of such other fire-resisting material and construction as may be approved by the licensing authority with treads not less than [27.5 cm] [Substituted by G.O. Ms. No. 3999, Home, dated 23rd November 1962.] wide and with risers not more than [1.5cm] [Substituted by G.O. Ms. No. 3999, Home, dated 23rd November 1962.] high (each lapping at least [2.5 cm] [Substituted by G.O. Ms. No. 3999, Home, dated 23rd November 1962.] over the back edge of the step below it) in flights of not more than 15 or less than 3 steps.
