Codes - Common Residential Codes
Codes - Common Residential Codes
Codes - Common Residential Codes
MECHANICAL
62. CLOTHES DRYERS. Section M1502.1 IRC 2009, Section 504.6 IMC 2009
M1502.1 General. Clothes dryers shall be exhausted in accordance with the manufacturer’s instructions.
M1502.3 Duct termination. Exhaust ducts shall terminate on the outside of the building. Exhaust duct terminations shall
be in accordance with the dryer manufacturer’s installation instructions.
If the manufacturer’s instructions do not specify a termination location, the exhaust duct shall terminate not less than 3
feet (914 mm) in any direction from openings into buildings. Exhaust duct terminations shall be equipped with a backdraft
damper. Screens shall not be installed at the duct termination.
M1502.4 Dryer exhaust ducts. Dryer exhaust ducts shall conform to the requirements of Sections M1502.4.1 through
M1502.4.6.
M1502.4.1 Material and size. Exhaust ducts shall have a smooth interior finish and shall be constructed of metal a
minimum 0.016-inch (0.4 mm) thick. The exhaust duct size shall be 4 inches (102 mm) nominal in diameter.
M1502.4.2 Duct installation. Exhaust ducts shall be supported at 4 foot (1219 mm) intervals and secured in place. The
insert end of the duct shall extend into the adjoining duct or fitting in the direction of airflow. Ducts shall not be joined
with screws or similar fasteners that protrude into the inside of the duct.
M1502.4.3 Transition duct. Transition ducts used to connect the dryer to the exhaust duct system shall be a single length
that is listed and labeled in accordance with UL 2158A. Transition ducts shall be a maximum of 8 feet (2438 mm) in
length. Transition ducts shall not be concealed within construction.
M1502.4.4 Duct length. The maximum allowable exhaust duct length shall be determined by one of the methods
specified in Section M1502.4.4.1 or M1502.4.4.2.
M1502.4.4.1 Specified length. The maximum length of the exhaust duct shall be 25 feet (7620 mm) from the connection
to the transition duct from the dryer to the outlet terminal. Where fittings are used, the maximum length of the exhaust
duct shall be reduced in accordance with Table M1502.4.4.1.
M1502.4.4.2 Manufacturer’s instructions. The size and maximum length of the exhaust duct shall be determined by the
dryer manufacturer’s installation instructions. The code official shall be provided with a copy of the installation
instructions for the make and model of the dryer at the concealment inspection. In the absence of fitting equivalent length
calculations from the clothes dryer manufacturer, Table M1502.4.4.1 shall be used.
M1502.4.5 Length identification. Where the exhaust duct is concealed within the building construction, the equivalent
length of the exhaust duct shall be identified on a permanent label or tag. The label or tag shall be located within 6 feet
(1829 mm) of the exhaust duct connection.
M1502.4.6 Exhaust duct required. Where space for a clothes dryer is provided, an exhaust duct system shall be
installed. Where the clothes dryer is not installed at the time of occupancy the exhaust duct shall be capped or plugged in
the space in which it originates and identified and marked “future use.”
Exception: Where a listed condensing clothes dryer is installed prior to occupancy of the structure.
63. FACTORY-BUILT FIREPLACES AND WOOD STOVES. R1004, R1005 IRC 2009, 903.1 IMC 2009
R1004.1 General. Factory-built fireplaces shall be listed and labeled and shall be installed in accordance with the
conditions of the listing. Factory-built fireplaces shall be tested in accordance with UL 127.
R1005.1 Listing. Factory-built chimneys shall be listed and labeled and shall be installed and terminated in accordance
with the manufacturer’s installation instructions.
64. HEARTH EXTENSIONS. Section R1001.10, R1004.2 IRC 2009
R1001.10 Hearth extension dimensions. Hearth extensions shall extend at least 16 inches (406 mm) in front of and at
least 8 inches (203 mm) beyond each side of the fireplace opening. Where the fireplace opening is 6 square feet (0.557
m2) or larger, the hearth extension shall extend at least 20 inches (508 mm) in front of and at least 12 inches (305 mm)
beyond each side of the fireplace opening.
R1004.2 Hearth extensions. Hearth extensions of approved factory-built fireplaces shall be installed in accordance with
the listing of the fireplace. The hearth extension shall be readily distinguishable from the surrounding floor area.
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67. MASONRY CHIMNEY HEIGHT AND SUPPORT. R1003 IRC 2009
R1003.9 Termination. Chimneys shall extend at least 2 feet (610 mm) higher than any portion of a building within 10
feet (3048 mm), but shall not be less than 3 feet (914 mm) above the point where the chimney passes through the roof.
R1003.2 Footings and foundations. Footings for masonry chimneys shall be constructed of concrete or solid masonry at
least 12 inches (305 mm) thick and shall extend at least 6 inches (152 mm) beyond the face of the foundation or support
wall on all sides. Footings shall be founded on natural undisturbed earth or engineered fill below frost depth. In areas not
subjected to freezing, footings shall be at least 12 inches (305 mm) below finished grade.
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70. LPG APPLIANCES. Section M2005 IRC 2009
M2005.2 Prohibited locations. Fuel-fired water heaters shall not be installed in a room used as a storage closet. Water
heaters located in a bedroom or bathroom shall be installed in a sealed enclosure so that combustion air will not be taken
from the living space. Direct-vent water heaters are not required to be installed within an enclosure.
M2005.2.1 Water heater access. Access to water heaters that are located in an attic or under floor crawl space is
permitted to be through a closet located in a sleeping room or bathroom where ventilation of those spaces is in accordance
with this code.
71. COMBUSTION, VENTILATION AND DILUTION AIR Section M1701, G2407 (304) IRC 2009
Section M1701 General
M1701.1 Scope. Solid-fuel-burning appliances shall be provided with combustion air in accordance with the appliance
manufacturer’s installation instructions. Oil-fired appliances shall be provided with combustion air in accordance with
NFPA 31. The methods of providing combustion air in this chapter do not apply to fireplaces, fireplace stoves and direct-
vent appliances. The requirements for combustion and dilution air for gas-fired appliances shall be in accordance with
Chapter 24.
M1701.2 Opening location. In areas prone to flooding as established in Table R301.2(1), combustion air openings shall
be located at or above the elevation required in Section R322.2.1 or R322.3.2.
G2407.1 (304.1) General. Air for combustion, ventilation and dilution of flue gases for appliances installed in buildings
shall be provided by application of one of the methods prescribed in Sections G2407.5 through G2407.9. Where the
requirements of Section G2407.5 are not met, outdoor air shall be introduced in accordance with one of the methods
prescribed in Sections G2407.6 through G2407.9. Direct-vent appliances, gas appliances of other than natural draft
design and vented gas appliances
other than Category I shall be provided with combustion, ventilation and dilution air in accordance with the appliance
manufacturer’s instructions.
Exception: Type 1 clothes dryers that are provided with makeup air in accordance with Section G2439.4.
G2407.5 (304.5) Indoor combustion air. The required volume of indoor air shall be determined in accordance with
Section G2407.5.1 or G2407.5.2, except that where the air infiltration rate is known to be less than 0.40 air changes per
hour (ACH), SectionG2407.5.2 shall be used. The total required volume shall be the sum of the required volume
calculated for all appliances located within the space. Rooms communicating directly with the space in which the
appliances are installed through openings not furnished with doors, and through combustion air openings sized and
located in accordance with Section G2407.5.3, are considered to be part of the required volume.
G2407.5.3 (304.5.3) Indoor opening size and location. Openings used to connect indoor spaces shall be sized and
located in accordance with Sections G2407.5.3.1 and G2407.5.3.2 (see Figure G2407.5.3).
G2407.5.3.1 (304.5.3.1) Combining spaces on the same story. Each opening shall have a minimum free area of
1 square inch per 1,000 Btu/h (2,200 mm2/kW) of the total input rating of all appliances in the space, but not less than
100 square inches (0.06 m2). One opening shall commence within 12 inches (305mm) of the top and one opening shall
commence within 12 inches (305 mm) of the bottom of the enclosure. The minimum dimension of air openings shall be
not less than 3 inches (76 mm).
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G2407.5.3.2 (304.5.3.2) Combining spaces in different stories. The volumes of spaces in different stories shall
be considered as communicating spaces where such spaces are connected by one or more openings in doors or floors
having a total minimum free area of 2 square inches per 1,000 Btu/h (4402mm2/kW) of total input rating of all
appliances.
G2407.6 (304.6) Outdoor combustion air. Outdoor combustion air shall be provided through opening(s) to the outdoors
in accordance with Section G2407.6.1 or G2407.6.2. The minimum dimension of air openings shall be not less than 3
inches (76 mm).
G2407.6.1 (304.6.1) Two-permanent-openings method. Two permanent openings, one commencing within 12
inches (305 mm) of the top and one commencing within 12 inches (305 mm) of the bottom of the enclosure, shall be
provided. The openings shall communicate directly, or by ducts, with the outdoors or spaces that freely communicate with
the outdoors.
Where directly communicating with the outdoors, or where communicating with the outdoors through vertical
ducts, each opening shall have a minimum free area of 1 square inch per 4,000 Btu/h (550mm2/kW) of total input rating
of all appliances in the enclosure [see Figures G2407.6.1(1) and G2407.6.1(2)]. Where communicating with the outdoors
through horizontal ducts, each opening shall have a minimum free area of not less than 1 square inch per 2,000 Btu/h
(1,100 mm2/kW) of total input rating of all appliances in the enclosure [see Figure G2407.6.1(3)].
G2407.6.2 (304.6.2) One-permanent-opening method. One permanent opening, commencing within 12 inches
(305 mm) of the top of the enclosure, shall be provided. The appliance shall have clearances of at least 1 inch (25 mm)
from the sides and back and 6 inches (152 mm) from the front of the appliance. The opening shall directly communicate
with the outdoors or through a vertical or horizontal duct to the outdoors, or spaces that freely communicate with the
outdoors (see Figure G2407.6.2) and shall have a minimum free area of 1 square inch per 3,000 Btu/h (734 mm2/kW) of
the total input rating of all appliances located in the enclosure and not less than the sum of the areas of all vent connectors
in the space.
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