(A) Where metal smoke pipes of 12 inches or less in diameter pass through a wood or plastered stud partition, they shall be surrounded either by a body of brick, hollow tile or other incombustible fireproof material of a thickness of at least four inches around such smoke pipes; or they shall be surrounded by a sheet metal thimble of two concentric rings at least two inches apart and the entire thimble so constructed that there will be a free circulation of air between the two rings forming the same. Smoke pipes of a diameter of six inches or less may have thimbles with one-inch air space.
(B) Where a new smoke pipe is installed, it shall be lock-seamed or riveted, with all joints lapped not less than one and one-half inches and rigidly secured and shall have proper thimble for making tight connection to chimney flue.
(Ord. 19, passed 1-7-1955)