(a) General Requirements.
(1) Chimneys, flues, gas vents and their supports shall be installed and maintained so as to be structurally safe, durable, smoke-tight, noncombustible and capable of withstanding the action of flue gases without softening, cracking, corroding or spalling.
(2) Such facilities shall effectively convey the products of combustion to the outer air.
(3) Masonry chimneys, except approved prefabricated chimneys, shall have noncombustible foundations.
(4) Flue linings shall be capable of withstanding the action of flue gas without softening, cracking, corroding or spalling at the temperature to which they will be subjected.
(5) Openings for smoke pipes or gas vent connections shall be provided with means for easy connection without restriction of flue.
(6) No flue shall have smoke pipe or gas vents connections in more than one story of a building.
(7) Fuel-burning equipment and fireplaces located in different dwelling units shall not be connected to the same flue.
(b) Fire Safety. Chimneys, flues and gas vents shall be installed and maintained so that under conditions of use, the temperature of any combustible material adjacent thereto, insulated therefrom or in contact therewith, does not exceed a safe temperature.
(c) Spark Arresters. A chimney or flue connected to an incinerator and a chimney or flue which may emit sparks, shall be provided with a spark arrester of noncombustible construction. Spark arresters shall have sufficient total clear area to permit unrestricted passage of flue gases. Openings in spark arresters shall be of such size as to prevent passage of embers and to minimize clogging by soot.