N.Y.C. Admin. Code § BC 711: Section BC 711: Horizontal Assemblies

711.1 General.

Horizontal assemblies shall comply with Section 711.2. Nonfire-resistance-rated floor and roof assemblies shall comply with Section 711.3.

711.2 Horizontal assemblies.

Horizontal assemblies shall comply with Sections 711.2.1 through 711.2.6.

711.2.1 Materials.

Horizontal assemblies shall be of materials permitted by the building type of construction.

711.2.1.1 Noncombustible materials.

Horizontal floor or roof assemblies shall be of noncombustible materials when such assemblies serve as horizontal offsets to fire walls or fire barriers required to be noncombustible.

711.2.2 Continuity.

Assemblies shall be continuous without vertical openings, except as permitted by this section and Section 712.

711.2.3 Supporting construction.

The supporting construction shall be protected to afford the required fire-resistance rating of the horizontal assembly supported.

Exception: In buildings of Type IIB, IIIB or VB construction, the construction supporting the horizontal assembly is not required to be fire-resistance-rated at the following:

1. Horizontal assemblies at the separations of incidental uses as specified by Table 509 provided the required fire-resistance rating does not exceed 1 hour.

2. Horizontal assemblies at the separations of dwelling units and sleeping units as required by Section 420.3.

3. Horizontal assemblies at smoke barriers constructed in accordance with Section 709.

711.2.4 Fire-resistance rating.

The fire-resistance rating of horizontal assemblies shall comply with Sections 711.2.4.1 through 711.2.4.6 but shall be not less than that required by the building type of construction.

711.2.4.1 Separating mixed occupancies.

Where the horizontal assembly separates mixed occupancies, the assembly shall have a fire-resistance rating of not less than that required by Section 508.4 based on the occupancies being separated.

711.2.4.2 Separating fire areas.

Where the horizontal assembly separates a single occupancy into different fire areas, the assembly shall have a fire-resistance rating of not less than that required by Section 707.3.10.

711.2.4.3 Dwelling units and sleeping units.

Horizontal assemblies serving as dwelling or sleeping unit separations in accordance with Section 420.3, located in Group I-1 and R occupancies, shall be not less than 1-hour fire-resistance-rated construction.

711.2.4.4 Separating smoke compartments.

Where the horizontal assembly is required to be a smoke barrier, the assembly shall comply with Section 709.

711.2.4.5 Separating incidental uses.

Where the horizontal assembly separates incidental uses from the remainder of the building, the assembly shall have a fire-resistance rating of not less than that required by Section 509.

711.2.4.6 Other separations.

Where a horizontal assembly is required by other sections of this code, the most restrictive fire-resistance rating shall govern.

711.2.5 Ceiling panels.

Where the weight of lay-in ceiling panels, used as part of fire-resistance-rated floor/ceiling or roof/ceiling assemblies, is not adequate to resist an upward force of 1 pound per square foot (47.8 Pa), wire or other approved devices shall be installed above the panels to prevent vertical displacement under such upward force.

711.2.6 Crawl spaces.

In 1-hour fire-resistance-rated floor/ceiling assemblies, the ceiling membrane is not required to be installed over crawl spaces that are not intended for occupancy or storage and that are less than 24 inches (609.6 mm) in height. Where the ceiling membrane is not provided, occupancy or storage is not permitted in the crawl space.

711.2.7 Attic spaces.

In 1-hour fire-resistance-rated roof assemblies, the floor membrane is not required to be installed where the attic space above the floor membrane is not intended for occupancy or storage. Where the floor membrane is not provided, occupancy or storage is not permitted in the attic space.

711.3 Nonfire-resistance-rated floor and roof assemblies.

Nonfire-resistance-rated floor, floor/ceiling, roof and roof/ceiling assemblies shall comply with Sections 711.3.1 and 711.3.2.

711.3.1 Materials.

Assemblies shall be of materials permitted by the building type of construction.

711.3.2 Continuity.

Assemblies shall be continuous without vertical openings, except as permitted by Section 712.