§ 27-872 Chimney connector clearances.
AC § 27-872
(a)From combustible construction. The minimum distance between the chimney connector and any combustible material or construction shall be: (1) eighteen inches for chimney connectors from low temperature equipment.
(2)thirty-six inches for chimney connectors from medium temperature and high temperature equipment.
(b)Reduced clearances. The above clearances may be reduced as outlined in table 15-8 in accordance with the type of protection applied to the combustible material or construction. TABLE 15-8Reduced Clearances for Chimney Connectorswith Specified Form of Protection1,2,3,4 Type of Protection Where the required clearance with no protection is:Applied to the combustible material and covering all surfaces within the distance specified as the required clearance with no protection.36 in.18 in.9 in.6 in.Thicknesses are minimum. (a) 0.027 in. (23 gauge) sheet metal spaced out 1 in.18 in. 9 in.4 in.2 in. (b) 3 1/2 in. thick masonry wall spaced out 1 in. and adequately tied to the wall being protected.18 in. 9 in.4 in.2 in. (See Note 4.) (c) 0.027 in. (23 gauge) sheet metal on 1 in. mineral wool batts reinforced with wire or equivalent spaced out in 1 in.12 in. 3 in.2 in.2 in. NOTES: 1. Spacers and ties shall be of noncombustible material.
2.All methods of protection require adequate ventilation between protective material and adjacent combustible walls and ceilings.
3.Mineral wool batts (blanket or board) shall have a minimum density of 8 lb. per cu. ft. and a minimum melting point of 1,500°F.
4.If a single wall connector passes through the masonry wall there shall be at least 1/2 in. open ventilated airspace between the connector and the masonry.
