607.1.1 Ducts and air transfer openings.
MC § 607.1.1
Ducts transitioning horizontally between shafts shall comply with one of the following: 1. The horizontal enclosure between shafts shall match the required rating of the shafts.
2.Fire-resistive duct assemblies shall be provided in accordance with Section 604. The duct assembly shall comply with all of the following: 2.1. Ducts shall not be within the scope of Sections 502.10, 504, 506.3, 510, or 511; and 2.2. Ducts shall not be lined with nor convey combustible materials; and 2.3. Ducts shall not be constructed of materials that are sensitive to thermal shock.
3.The horizontal offset duct shall be provided with combination fire-smoke dampers at the penetration of each shaft. The duct system shall comply with all of the following: 3.1. Ducts shall not be within the scope of Sections 502.10, 504, 506.3, 510, or 511; and 3.2. The duct system shall be a type permitted to include dampers; and 3.3. Protection of penetrations of the shaft enclosure shall not utilize exceptions requiring continuous air movement.
