(a) Required flue linings and thimbles shall be made of fire clay or other refractory materials which will withstand the action of flue gases and resist, without softening or cracking, the temperatures to which they will be subjected, but not less than 2,000 degrees Fahrenheit, or such linings shall be of cast iron of approved quality, form or construction. Approved corrosion-resistant linings may be used in flues for gas appliances.
(b) Required clay flue linings shall be not less than five-eighths of an inch thick for the smaller flues and increasing in thickness for the larger flues.
(c) Flue linings shall, when possible, be built ahead of the construction of the chimney as it is carried up, be carefully bedded one on the other in mortar as hereinafter specified, with close-fitting joints left smooth on the inside. The practice of building up chimney walls hollow for a number of courses and then dropping a section of flue lining into this hollow space shall not be permitted. Openings for smoke pipes or vents into flues and clean-out openings shall be built in as the chimney is constructed and shall not be cut in after the flue construction has been completed. When flues change their direction, the ends of the flue linings must be cut to make a proper fit at the angles or at the points of change in direction.
(d) Flue linings shall start at the top of the cleanout opening, but in no case less than eight inches below the intake. For fireplaces, flue linings shall start at the throat of the fireplace. The linings shall extend, as nearly vertically as possible, for the entire height of the chimney and for not less than four inches above the top or cap of the chimney.
(e) Cleanouts for flues and fireplaces shall be provided and shall be equipped with approved iron or steel doors and frames arranged to remain tightly closed when not in use and readily accessible.
(f) Only Portland cement mortar, cement lime mortar or fire clay mortar shall be used in setting flue linings.
(g) When more than two flues are contained in the same chimney, at least every third flue shall be separated by masonry at least three and three-fourths of an inch thick and which shall be bonded into the masonry wall of the chimney. Flue linings shall be staggered at least seven inches.
(Ord. 42-1981. Passed 2-23-81.)