(a) This section shall apply to vents for gas burning water heaters within apartments of multiple dwellings as required by §27-887(d) of the Administrative Code (Building Code) and to gas appliances in rooms or spaces without a window opening to the outer air, used for living or sleeping within a multiple dwelling, where required by the provisions of § 64 of the Multiple Dwelling Law.
(b) Vents shall consist of galvanized iron of not less than No. 26 U.S. gauge in thickness, cement-asbestos pipe, metal-asbestos pipe, enamelled steel pipe of a quality acceptable to the Department as heat and corrosion resistant, or other materials satisfactory to the superintendent.
(c) Vents shall have a cross-sectional area at least equal to the area of the vent outlet of the appliance and shall have a minimum diameter or dimension of three (3) inches.
(d) Vents shall lead to a flue or to the outer air as follows:
(1) Several vents may be connected to a flue if the cross-sectional area of the flue is equal to or greater than the total cross-sectional area of all vents so connected. No vent from a water heater or other gas appliance within an apartment may be connected to a flue serving a central heating plant.
(2) Vents may be connected to a flue serving appliances burning other than gas fuel provided the connection of the gas appliance to the flue is at least nine (9) inches above the connection of the other heat producing device, or through a suitable "Y" connection in a common vent pipe of proper diameter.
(3) Every flue to which a vent from a gas water heater is attached, shall extend to a distance of not less than four (4) feet above a flat roof, or two (2) feet above a pitched roof. Such flues on the exterior of a building, and the portions of the vent pipes on the exterior of a building, shall consist of standard water, steam or soil pipe, cement-asbestos pipe, metal-asbestos pipe, or other corrosion resistant material satisfactory to the Department. Flues and vent pipes on the exterior of buildings shall be adequately supported and braced. Flues within buildings shall be constructed as low temperature chimneys.
(4) Vents leading to an outside flue or terminating at the exterior of the building may pass through the upper part of a window if the vent is adequately secured in place and provided the vent is so arranged as to give minimum interference with the operation of the window, provided the area of the windows in the room after alteration equals or exceeds that required by law. Vents may also pass through an exterior wall by means of a metal sleeve placed in the wall. The metal sleeve shall consist of standard water, steam, or soil pipe, cement-asbestos pipe, or other approved material. The space between the sleeve and the vent shall be filled with incombustible material.
(5) Vent pipes may be terminated at the exterior of an outside wall of a building in which case the vents shall be turned upward for not less than ten (10) inches, except that for any vent pipes installed after June 30, 1955, the vertical rise of the vent pipe shall not be less than one and one-third times the length of the horizontal run of the vent pipe. No vent pipe shall terminate below the level of the top of a window unless at least three (3) feet distant from any part of the window. Vents shall be capped with an approved tee. Vents on the exterior of a building shall comply with the provisions of paragraph (4), subdivision (d) of this section as to the material that may be used.
(e) Vent pipes shall be installed so as to provide a minimum clearance of three (3) inches on all sides from combustible material. Vent pipes shall not pass through a floor unless approved by the superintendent.
(f) Where a vent pipe passes through a partition or roof constructed wholly or in part of combustible material, a ventilated metal thimble not less than six (6) inches larger in diameter than the pipe, shall be provided. Any material used to fill the space between the vent pipe and the thimble shall be incombustible.
(g) Every vent pipe serving as a gas water heater shall be provided with a draft hood unless the water heater has an approved built-in draft hood. The draft hood shall be approved by a recognized testing laboratory as conforming to nationally accepted standards. The draft hood shall be installed at the flue collar or as near to the appliance as possible and in the position for which it was designed, with reference to horizontal and vertical planes. The relief opening of the draft hood shall not be obstructed.
(h) The horizontal run of vent pipe shall not exceed three-fourths of the vertical rise of the flue to which the vent is attached. The vent pipe shall be pitched upward from the water heater with a slope of not less than one-fourth inch vertically for each foot of horizontal run.
(i) No dampers, steel wool or other obstructions shall be placed in any vent pipe or flue.
(j) A permit shall be obtained from the Department of Buildings before any vertical flue or chimney is constructed.