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Title: Section 709  •  Size: 13396

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SECTION 709 - WALLS AND PARTITIONS

709.1 General. Fire-resistive walls and partitions shall be assumed to have the fire-resistance ratings set forth in Table 7-B.

709.2 Combustible Members. Combustible members framed into a wall shall be protected at their ends by not less than one half the required fire-resistive thickness of such wall.

709.3 Exterior Walls.

709.3.1 Extension through attics and concealed spaces. In fire-resistive exterior wall construction, the fire-resistive rating shall be maintained for such walls passing through attic areas or other areas containing concealed spaces.

709.3.2 Vertical fire spread at exterior walls.

709.3.2.1 General. The provisions of this section are intended to restrict the passage of smoke, flame and hot gases from one floor to another at exterior walls. See Section 710 for floor penetrations.

709.3.2.2 Interior. When fire-resistive floor or floor-ceiling assemblies are required, voids created at the intersection of the exterior wall assemblies and such floor assemblies shall be sealed with an approved material. Such material shall be securely installed and capable of preventing the passage of flame and hot gases sufficient to ignite cotton waste when subjected to U.B.C. Standard 7-1 time-temperature fire conditions under a minimum positive pressure differential of 0.01 inch (0.25 mm) of water column for the time period at least equal to the fire-resistance rating of the floor assembly.

709.3.2.3 Exterior. When openings in an exterior wall are above and within 5 feet (1524 mm) laterally of an opening in the story below, such openings shall be separated by an approved flame barrier extending 30 inches (762 mm) beyond the exterior wall in the plane of the floor or by approved vertical flame barriers not less than 3 feet (914 mm) high measured vertically above the top of the lower opening. Flame barriers shall have a fire resistance of not less than three-fourths hour.

EXCEPTIONS: 1. Flame barriers are not required in buildings equipped with an approved automatic sprinkler system throughout.

2. This section shall not apply to buildings of three stories or less in height.

709.4 Parapets.

709.4.1 General. Parapets shall be provided on all exterior walls of buildings.

EXCEPTION: A parapet need not be provided on an exterior wall when any of the following conditions exist:

1. The wall is not required to be of fire-resistive construction.

2. The wall, due to location on property line, may have unprotected openings.

3. The building has an area of not more than 1,000 square feet (93 m²) on any floor.

4. Walls which terminate at roofs of not less than two-hour fire-resistive construction or roofs constructed entirely of noncombustible materials.

5. One-hour fire-resistive exterior walls may terminate at the underside of the roof sheathing, deck or slab, provided:

5.1 Where the roof-ceiling framing elements are parallel to the walls, such framing and elements supporting such framing shall not be of less than one-hour fire-resistive construction for a width of 5 feet (1524 mm) measured from the interior side of the wall for Groups U and R Occupancies and 10 feet (3048 mm) for all other occupancies.

5.2 Where roof-ceiling framing elements are perpendicular to the wall, the entire span of such framing and elements supporting such framing shall not be of less than one-hour fire-resistive construction.

5.3 Openings in the roof shall not be located within 5 feet (1524 mm) of the one-hour fire-resistive exterior wall for Groups U and R Occupancies and 10 feet (3048 mm) for all other occupancies.

5.4 The entire building shall be provided with not less than a Class B roof covering.

709.4.2 Construction. Parapets shall have the same degree of fire resistance required for the wall upon which they are erected, and on any side adjacent to a roof surface, shall have noncombustible faces for the uppermost 18 inches (457 mm), including counterflashing and coping materials. The height of the parapet shall not be less than 30 inches (762 mm) above the point where the roof surface and the wall intersect. Where the roof slopes toward a parapet at slopes greater than 2 units vertical in 12 units horizontal (16.7% slope), the parapet shall extend to the same height as any portion of the roof that is within the distance where protection of wall openings would be required, but in no case shall the height be less than 30 inches (762 mm).

709.5 Nonsymmetrical Wall Construction. Walls and partitions of nonsymmetrical construction shall be tested with both faces exposed to the furnace, and the assigned fire-resistive rating will be the shortest duration obtained from the two tests conducted in conformance with U.B.C. Standard 7-1. When evidence is furnished to show that the wall was tested with the least fire-resistive side exposed to the furnace, subject to acceptance of the building official, the wall need not be subjected to tests from the opposite side.

709.6 Through Penetration. Penetrating items passing entirely through both protective membranes of bearing walls required to have a fire-resistance rating and walls requiring protected openings shall be protected with through-penetration fire stops suitable for the method of penetration.

EXCEPTIONS: 1. Penetrations not larger than a 4-inch (100 mm) nominal pipe or 16 square inches (10 320 mm²) in overall cross-sectional area containing noncombustible penetrating items, where the annular space between the penetrating items and the wall assembly being penetrated is filled with a material which will prevent the passage of flame and hot gases sufficient to ignite cotton waste when subjected to U.B.C. Standard 7-1 time-temperature fire conditions under a minimum positive pressure differential of 0.01-inch (0.25 mm) water column at the location of the penetration for the time period at least equal to the fire-resistance rating of the wall assembly.

2. Penetrations not larger than a 4-inch (100 mm) nominal copper or ferrous pipe and conduit or 16 square inches (10 320 mm²) of overall cross-sectional area containing copper or ferrous penetrating items, where the annular space between the penetrating items and the wall assembly being penetrated is filled with concrete, grout or mortar for the full thickness of the wall assembly (or the thickness necessary to provide the required fire-resistance rating of the assembly being penetrated) at the location of the penetration in concrete and masonry wall assemblies.

The T rating for through-penetration fire stops in fire-rated walls requiring protected openings shall apply to penetrations in the following locations:

1. Above corridor ceilings which are not part of a fire-resistive assembly.

2. Below any ceiling.

EXCEPTION: Any through-penetrating item not larger than a 4-inch (100 mm) nominal pipe or 16 square inches (10 320 mm²) in overall cross-sectional area need not have a T rating.

709.7 Membrane Penetrations. Fire-resistive walls and partitions may have openings for steel electrical outlet boxes not exceeding 16 square inches (10 320 mm²) in area, provided the aggregate area of such openings is not more than 100 square inches (64 500 mm²) for any 100 square feet (9.3 m² of wall or partition area. Outlet boxes on opposite sides of walls and partitions shall be separated by a horizontal distance of at least 24 inches (610 mm).

Where wall-protective membranes are penetrated by other materials or where larger openings are required than permitted above, the penetrating items shall be:

1. Protected with membrane-penetration fire stops suitable for the methods of penetration, or

2. Installed in accordance with the installation instructions of their listing for such use.

EXCEPTION: Penetrations not larger than a 4-inch (100 mm) nominal pipe or 16 square inches (10 320 mm²) in overall cross-sectional area containing noncombustible penetrating items, where the annular space between the penetrating items and the protective membrane being penetrated is filled with a material which will prevent the passage of flame and hot gases sufficient to ignite cotton waste when subjected to U.B.C. Standard 7-1 time-temperature fire conditions under a minimum positive pressure differential of 0.01-inch (0.25 mm) water column at the location of the penetration for the time period at least equal to the fire-resistance rating of the wall assembly.

709.8 Construction Joints. Construction joints shall comply with the requirements of Section 706.

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