Binding
Interpretation 112 referenced sections
Chapter 2 -
Definitions
DWELLING UNIT. A
single unit providing complete independent living facilities for one or more
persons, including permanent provisions for living, sleeping, eating, cooking
and sanitation.
Chapter 3 – Building
and Planning
R302.3 Two-family dwellings.
Dwelling units in
two-family dwellings shall be separated from each other by wall and/or floor
assemblies having not less than a 1-hour fire-resistance rating when tested in
accordance with ASTM E 119 or UL 263. Fire-resistance-rated floor-ceiling and wall
assemblies shall extend to and be tight against the exterior wall,
and wall assemblies shall extend from the foundation to the underside of the
roof sheathing.
Exceptions:
1. A fire-resistance rating of 1/2 hour
shall be permitted in buildings equipped throughout with an automatic sprinkler
system installed in accordance with NFPA 13.
2. Wall assemblies need not extend through attic spaces
when the ceiling is protected by not less than 5/8-inch
(15.9 mm) Type X gypsum board and an attic draft stop
constructed as specified in Section R302.12.1 is provided above and along the
wall assembly separating the dwellings. The structural framing
supporting the ceiling shall also be protected by not less than 1/2-inch
(12.7 mm) gypsum board or equivalent.
3. Screen enclosure walls of insect screening with a maximum
of 25 percent solid flexible finishes.
R302.3.1 Supporting construction.
When floor assemblies are required to be fire-resistance rated by Section
R302.3, the supporting construction of such assemblies shall have an equal or
greater fire-resistance rating.
R302.4 Dwelling unit rated penetrations.
Penetrations of wall or floor/ceiling assemblies
required to be fire-resistance rated in accordance with Section R302.2 or
R302.3 shall be protected in accordance with this section.
R302.4.1 Through penetrations.
Through penetrations of fire-resistance-rated wall or floor assemblies shall
comply with Section R302.4.1.1 or R302.4.1.2.
Exception: Where the penetrating items are steel, ferrous or copper
pipes, tubes or conduits, the annular space shall be protected as follows:
1. In concrete or masonry wall or floor assemblies,
concrete, grout or mortar shall be permitted where installed to the full
thickness of the wall or floor assembly or the thickness required to maintain
the fire-resistance rating, provided:
1.1. The nominal diameter of the penetrating item is a maximum of
6 inches (152 mm); and
1.2. The area of the opening through the wall does not exceed 144
square inches (92 900 mm2).
2. The material used to fill the annular space shall prevent
the passage of flame and hot gases sufficient to ignite cotton waste where
subjected to ASTM E 119 or UL 263 time temperature fire conditions under a minimum
positive pressure differential of 0.01 inch of water (3 Pa) at the location of
the penetration for the time period equivalent to the fire resistance rating of
the construction penetrated.
R302.4.1.1 Fire-resistance-rated assembly.
Penetrations shall be installed as tested in the approved fire-resistance-rated
assembly.
R302.4.1.2 Penetration firestop system.
Penetrations shall be protected by an approved penetration
firestop system installed as tested in accordance with ASTM E 814 or UL 1479, with a minimum positive pressure differential of 0.01 inch
of water (3 Pa) and shall have an F rating of not less than the required
fire-resistance rating of the wall or floor/ceiling assembly penetrated.
R302.4.2 Membrane
penetrations.
Membrane penetrations shall comply with Section R302.4.1. Where walls are
required to have a fire-resistance rating, recessed fixtures shall be installed
so that the required fire-resistance rating will not be reduced.
Exceptions:
1. Membrane penetrations of maximum 2-hour fire-resistance-rated
walls and partitions by steel electrical boxes that do not exceed 16 square
inches (0.0103 m2) in area provided the aggregate area of the
openings through the membrane does not exceed 100 square inches (0.0645 m2)
in any 100 square feet (9.29 m)2 of wall area. The annular
space between the wall membrane and the box shall not exceed 1/8 inch
(3.1 mm). Such boxes on opposite sides of the wall shall be separated by one of
the following:
1.1. By a horizontal distance of not less than 24 inches
(610 mm) where the wall or partition is constructed with individual
noncommunicating stud cavities;
1.2. By a horizontal distance of not less than the depth of
the wall cavity when the wall cavity is filled with cellulose loose-fill,
rockwool or slag mineral wool insulation;
1.3. By solid fire blocking in accordance with Section R302.11;
1.4. By protecting both boxes with listed putty pads; or
1.5. By other listed materials and methods.
2. Membrane penetrations by listed electrical boxes of any
materials provided the boxes have been tested for use in fire-resistance-rated
assemblies and are installed in accordance with the instructions included in
the listing. The annular space between the wall membrane and the box shall not
exceed 1/8 inch (3.1 mm) unless listed
otherwise. Such boxes on opposite sides of the wall shall be separated by one
of the following:
2.1. By the horizontal distance specified in the listing of the
electrical boxes;
2.2. By solid fireblocking in accordance with Section R302.11;
2.3. By protecting both boxes with listed putty pads; or
2.4. By other listed materials and methods.
3. The annular space created by the penetration of a fire
sprinkler provided it is covered by a metal escutcheon plate