Chapter 5, Section 510.7.1, is hereby deleted in its entirety and the following provisions shall be substituted therefor:

In all buildings the ducts shall be enclosed in a continuous enclosure per Section 507.2.3 extending from the hood, through any concealed spaces, to or through the roof so as to maintain the integrity of the fire separations required by the applicable Building Code provisions. The enclosure shall be sealed around the duct at the point of penetration of the ceiling or floor above the hood in order to maintain the fire resistance rating of the enclosure and shall be vented to the exterior of the building through weather-protected openings.

Exception: The continuous enclosure provisions shall not be required where a field applied grease duct enclosure or a factory-built grease duct enclosure (see Section 507.2.3) is protected with a listed duct through penetration protection system equivalent to the fire resistance rating of the assembly being penetrated, and the materials are installed in accordance with the conditions of their listings and the manufacturers’ instructions and are acceptable to the Authority Having Jurisdiction.