3.1.8.9.Smoke Dampers Waived

(1) Except as provided in Sentence (2), the requirement for smoke dampers or combination smoke/fire dampers stated in Sentence 3.1.8.7.(2) is permitted to be waived for ducts (a) that serve commercial cooking equipment, (See also Article 6.3.1.6.) (b) in which all inlet and outlet openings serve not more than one fire compartment, (c) that penetrate a vertical fire separation referred to in Clause 3.3.1.7.(1)(b) or in Sentence 3.3.3.5.(4) or 3.3.4.11.(4), provided, (i) the movement of air is continuous, and (ii) the configuration of the air-handling system prevents the recirculation of exhaust or return air under fire emergency conditions, or (d) that penetrate a vertical fire separation not required to have a fire-resistance rating and located within the fire compartment required in Sentence 3.3.3.5.(2). (2) The requirement for smoke dampers or combination smoke/fire dampers stated in Sentence 3.1.8.7.(2) is permitted to be waived for noncombustible branch ducts having a melting point above 760°C that penetrate a fire separation, (a) provided the ducts (i) have a cross-sectional area not more than 0.013 m² and serve only air-conditioning units or combined air- conditioning and heating units discharging air not more than 1.2 m above the floor, (ii) extend not less than 500 mm inside exhaust duct risers that are under negative pressure and in which the airflow is upward as required by Article 3.6.3.4., or (iii) are required to function as part of an air handling system used to provide make-up air in accordance with Sentence 3.2.6.2.(6), or any other system used to limit smoke movement, or (b) where the fire separation separates a vertical service space from the remainder of the building, provided each individual duct exhausts directly to the outdoors at the top of the vertical service space.