Section 3280.206 - Fireblocking(a)General. Fireblocking must comply with the requirements of this section. The integrity of all fireblocking materials must be maintained.(b)Fireblocking materials. Fireblocking must consist of the following materials: (1) Minimum one inch nominal lumber, 5/16 inch thick gypsum board, or equivalent fire resistive materials; or(2) Other Listed or Approved Materials;(c)Fireblocking locations.(1) Fireblocking must be installed in concealed spaces of stud walls, partitions, and furred spaces at the floor and ceiling levels. Concealed spaces must not communicate between floor levels. Concealed spaces must not communicate between a ceiling level and a concealed roof area, or an attic space.(2) Fireblocking must be installed at the interconnection of a concealed vertical space and a concealed horizontal space that occurs:(i) Between a concealed wall cavity and the ceiling joists above; and(ii) At soffits, drop ceilings, cover ceilings, and similar locations.(3) Fireblocking must be installed around the openings for pipes, vents, and other penetrations in walls, floors, and ceilings of furnace and water heater spaces. Pipes, vents, and other penetrations that cannot be moved freely within their opening are considered to be fireblocked. Materials used to fireblock heat producing vent penetrations must be noncombustible or limited combustible types.71 FR 72042, Nov. 30, 2005