Page 88 - 2018_IRC

BUILDING PLANNING

R302.13 Fire protection of floors. Floor assemblies that are ing occupants. The openable area to the outdoors shall be not
not required elsewhere in this code to be fire-resistance rated, less than 4 percent of the floor area being ventilated.
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shall be provided with a / -inch (12.7 mm) gypsum wall- Exceptions:
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5
board membrane, / -inch (16 mm) wood structural panel
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membrane, or equivalent on the underside of the floor fram- 1. The glazed areas need not be openable where the
ing member. Penetrations or openings for ducts, vents, elec- opening is not required by Section R310 and a
trical outlets, lighting, devices, luminaires, wires, speakers, whole-house mechanical ventilation system is
drainage, piping and similar openings or penetrations shall be installed in accordance with Section M1505.
permitted.
2. The glazed areas need not be installed in rooms
Exceptions: where Exception 1 is satisfied and artificial light is
provided that is capable of producing an average
1. Floor assemblies located directly over a space pro- illumination of 6 footcandles (65 lux) over the area
tected by an automatic sprinkler system in accor- of the room at a height of 30 inches (762 mm) above
dance with Section P2904, NFPA 13D, or other the floor level.
approved equivalent sprinkler system.
3. Use of sunroom and patio covers, as defined in Sec-
2. Floor assemblies located directly over a crawl space tion R202, shall be permitted for natural ventilation if
not intended for storage or for the installation of in excess of 40 percent of the exterior sunroom walls
fuel-fired or electric-powered heating appliances.
are open, or are enclosed only by insect screening.
3. Portions of floor assemblies shall be permitted to be R303.2 Adjoining rooms. For the purpose of determining
unprotected where complying with the following: light and ventilation requirements, rooms shall be considered
3.1. The aggregate area of the unprotected por- to be a portion of an adjoining room where not less than one-
tions does not exceed 80 square feet (7.4 m ) half of the area of the common wall is open and unobstructed
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per story. and provides an opening of not less than one-tenth of the
floor area of the interior room and not less than 25 square feet
3.2. Fireblocking in accordance with Section (2.3 m ).
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R302.11.1 is installed along the perimeter of
the unprotected portion to separate the Exception: Openings required for light or ventilation shall
unprotected portion from the remainder of be permitted to open into a sunroom with thermal isolation
the floor assembly. or a patio cover, provided that there is an openable area
between the adjoining room and the sunroom or patio
4. Wood floor assemblies using dimension lumber or
structural composite lumber equal to or greater than cover of not less than one-tenth of the floor area of the
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2-inch by 10-inch (50.8 mm by 254 mm) nominal interior room and not less than 20 square feet (2 m ). The
dimension, or other approved floor assemblies minimum openable area to the outdoors shall be based on
demonstrating equivalent fire performance. the total floor area being ventilated.
R303.3 Bathrooms. Bathrooms, water closet compartments
R302.14 Combustible insulation clearance. Combustible
insulation shall be separated not less than 3 inches (76 mm) and other similar rooms shall be provided with aggregate glaz-
2
from recessed luminaires, fan motors and other heat-produc- ing area in windows of not less than 3 square feet (0.3 m ), one-
ing devices. half of which shall be openable.
Exception: The glazed areas shall not be required where
Exception: Where heat-producing devices are listed for
lesser clearances, combustible insulation complying with artificial light and a local exhaust system are provided.
3the listing requirements shall be separated in accordance The minimum local exhaust rates shall be determined in
with the conditions stipulated in the listing. accordance with Section M1505. Exhaust air from the
space shall be exhausted directly to the outdoors.
Recessed luminaires installed in the building thermal R303.4 Mechanical ventilation. Where the air infiltration
envelope shall meet the requirements of Section N1102.4.5 of rate of a dwelling unit is 5 air changes per hour or less where
this code.
tested with a blower door at a pressure of 0.2 inch w.c (50 Pa)
in accordance with Section N1102.4.1.2, the dwelling unit
shall be provided with whole-house mechanical ventilation in
SECTION R303 accordance with Section M1505.4.
LIGHT, VENTILATION AND HEATING
R303.5 Opening location. Outdoor intake and exhaust open-
R303.1 Habitable rooms. Habitable rooms shall have an ings shall be located in accordance with Sections R303.5.1
aggregate glazing area of not less than 8 percent of the floor and R303.5.2.
area of such rooms. Natural ventilation shall be through win-
dows, skylights, doors, louvers or other approved openings to R303.5.1 Intake openings. Mechanical and gravity out-
the outdoor air. Such openings shall be provided with ready door air intake openings shall be located not less than 10
access or shall otherwise be readily controllable by the build- feet (3048 mm) from any hazardous or noxious contami-

2018 INTERNATIONAL RESIDENTIAL CODE ® 63
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