HomeMy WebLinkAbout20212312.tiffSec. 29-2-30. - International lesidential Code.
The publication of the International Code Council, Inc., known as the International Residential Code
(IRC), 2018 Edition, including the following International Residential Code Appendices: Appendix H,
Appendix J, Appendix NI,, c Appendix Q and Appendix F are incorporated by this reference as part of
this Building Code for the pu -pose of establishing standards for the construction and inspection of
dwellings, buildings and structures and the issuance of building permits in the County, (Appendix G of
the 2012 Edition shall remain the same and be enforced accordingly), with the following amendments:
Section A though U unchanged oGn
2018 International Residential Code "Appendix F"
ppEN E
RADON CONTROL METHODS,
attached for reference
The provisions contained in this appendix are not mandatory unless specifically referenced in the
adopting ordinance.
SECTION AF101
SCOPE
a. pCi/L standard fir picocuries per liter of radon gas. The U.S. Environmental Protection Agency
(EPA) recommends that homes that measure 4 pCi/L and greater be mitigated.
The EPA and the U.S. Geological Survey have evaluated the radon potential in the United States and
have developed a map cf radon zones designed to assist building officials in deciding whether radon
resistant features are applicable in new construction.
The map assigns each of the 3,141 counties in the United States to one of three zones based on radon
potential. Each zone designation reflects the average short-term radon measurement that can be
expected to be measured in a building without the implementation of radon -control methods. The
radon zone designation of highest priority is Zone 1. Table AF101 lists the Zone 1 counties illustrated on
the map. More detailed information can be obtained from state -specific booklets (EPA -402-R-93-021
through 070) available through State Radon Offices or from EPA Regional Offices.
FIGURE AF101
EPA MAP OF RADON ZONES
TABLE AF101(1)
HIGH RADON-POTE TIAL (ZONE 1) COUNTIESa
2021-2312
a. The EPA recommends that this county listing be supplemented with other available State and
local data to further understand the radon potential of a Zone 1 area.
AF101.1 General.
This appendix contains requirements for new construction in jurisdictions where radon -resistant
construction is required.
Inclusion of this appendix by jurisdictions shall be determined through the use of locally available data
or determination of Zone 1 designation in Figure AF101 and Table AF101(1).
SECTION AF102
DEFINITIONS
AF102.1 General.
For the purpose of these requirements, the terms used shall be defined as follows:
DRAIN TILE LOOP. A continuous length of drain tile or perforated pipe extending around all or part of the
internal or external perimeter of a basement or crawl space footing.
RADON GAS. A naturally occurring, chemically inert, radioactive gas that is not detectable by human
senses. As a gas, it can move readily through particles of soil and rock, and can accumulate under the
slabs and foundations of homes where it can easily enter into the living space through construction
cracks and openings.
SOIL -GAS -RETARDER. A continuous membrane of 6 -mil (0.15 mm) polyethylene or other equivalent
material used to retard the flow of soil gases into a building.
SUBMEMBRANE DEPRESSURIZATION SYSTEM. A system designed to achieve lower submembrane air
pressure relative to crawl space air pressure by use of a vent drawing air from beneath the soil -gas -
retarder membrane.
SUBSLAB DEPRESSURIZATION SYSTEM (Active). A system designed to achieve lower subslab air pressure
relative to indoor air pressure by use of a fan -powered vent drawing air from beneath the slab.
SUBSLAB DEPRESSURIZATION SYSTEM (Passive). A system designed to achieve lower subslab air
pressure relative to indoor air pressure by use of a vent pipe routed through the conditioned space of a
building and connecting the subslab area with outdoor air, thereby relying on the convective flow of air
upward in the vent to draw air from beneath the slab.
SECTION AF103
REQUIREMENTS
FIGURE AF103
RADON -RESISTANT CONSTRUCTION DETAILS FOR FOUR FOUNDATION TYPES
AF103.1 General.
The following construction techniques are intended to resist radon entry and prepare the building for
post -construction radon mitigation, if necessary (see Figure AF103). These techniques are required in
areas where designated by the jurisdiction.
AF103.2 Subfloor preparation.
A layer of gas -permeable material shall be placed under all concrete slabs and other floor systems that
directly contact the ground and are within the walls of the living spaces of the building, to facilitate
future installation of a subslab depressurization system, if needed. The gas -permeable layer shall consist
of one of the following:
1. A uniform layer of clean aggregate, not less than 4 inches (102 mm) thick. The aggregate shall
consist of material that will pass through a 2 -inch (51 mm) sieve and be retained by a 1/4 -inch (6.4 mm)
sieve.
2. A uniform layer of sand (native or fill), not less than 4 inches (102 mm) thick, overlain by a layer
or strips of geotextile drainage matting designed to allow the lateral flow of soil gases.
3. Other materials, systems or floor designs with demonstrated capability to permit
depressurization across the entire subfloor area.
AF103.3 Soil -gas -retarder.
A minimum 6 -mil (0.15 mm) [or 3 -mil (0.075 mm) cross -laminated] polyethylene or equivalent flexible
sheeting material shall be placed on top of the gas -permeable layer prior to casting the slab or placing
the floor assembly to serve as a soil -gas -retarder by bridging any cracks that develop in the slab or floor
assembly, and to prevent concrete from entering the void spaces in the aggregate base material. The
sheeting shall cover the entire floor area with separate sections of sheeting lapped not less than 12
inches (305 mm). The sheeting shall fit closely around any pipe, wire or other penetrations of the
material. Punctures or tears in the material shall be sealed or covered with additional sheeting.
AF103.4 Entry routes.
Potential radon entry routes shall be closed in accordance with Sections AF103.4.1 through AF103.4.10.
AF103.4.1 Floor openings.
Openings around bathtubs, showers, water closets, pipes, wires or other objects that penetrate
concrete slabs, or other floor assemblies, shall be filled with a polyurethane caulk or equivalent sealant
applied in accordance with the manufacturer's recommendations.
AF103.4.2 Concrete joints.
Control joints, isolation joints, construction joints, and any other joints in concrete slabs or between
slabs and foundation walls shall be sealed with a caulk or sealant. Gaps and joints shall be cleared of
loose material and filled with polyurethane caulk or other elastomeric sealant applied in accordance
with the manufacturer's recommendations.
AF103.4.3 Condensate drains..
Condensate drains shall be trapped or routed through nonperforated pipe to daylight.
AF103.4.4 Sumps.
Sump pits open to soil or serving as the termination point for subslab or exterior drain tile loops shall be
covered with a gasketed or otherwise sealed lid. Sumps used as the suction point in a subslab
depressurization system shall have a lid designed to accommodate the vent pipe. Sumps used as a floor
drain shall have a lid equipped with a trapped inlet.
AF103.4.5 Foundation walls.
Hollow block masonry foundation walls shall be constructed with either a continuous course of solid
masonry, one course of masonry grouted solid, or a solid concrete beam at or above finished ground
surface to prevent the passage of air from the interior of the wall into the living space. Where a brick
veneer or other masonry ledge is installed, the course immediately below that ledge shall be sealed.
Joints, cracks or other openings around all penetrations of both exterior and interior surfaces of
masonry block or wood foundation walls below the ground surface shall be filled with polyurethane
caulk or equivalent sealant. Penetrations of concrete walls shall be filled.
AF103.4.6 Dampproofing.
The exterior surfaces of portions of concrete and masonry block walls below the ground surface shall be
dampproofed in accordance with Section R406.
AF103.4.7 Air -handling units.
Air -handling units in crawl spaces shall be sealed to prevent air from being drawn into the unit.
Exception: Units with gasketed seams or units that are otherwise sealed by the manufacturer to prevent
leakage.
AF103.4.8 Ducts.
Ductwork passing through or beneath a slab shall be of seamless material unless the air -handling system
is designed to maintain continuous positive pressure within such ducting. Joints in such ductwork shall
be sealed to prevent air leakage.
Ductwork located in crawl spaces shall have seams and joints sealed by closure systems in accordance
with Section M1601.4.1.
AF103.4.9 Crawl space floors.
Openings around all penetrations through floors above crawl spaces shall be caulked or otherwise filled
to prevent air leakage.
AF103.4.10 Crawl space access.
Access doors and other openings or penetrations between basements and adjoining crawl spaces shall
be closed, gasketed or otherwise filled to prevent air leakage.
AF103.5 Passive submembrane depressurization system.
In buildings with crawl space foundations, the following components of a passive submembrane
depressurization system shall be installed during construction.
Exception: Buildings in which an approved mechanical crawl space ventilation system or other
equivalent system is installed.
AF103.5.1 Ventilation.
Crawl spaces shall be provided with vents to the exterior of the building. The minimum net area of
ventilation openings shall comply with Section R408.1.
AF103.5.2 Soil -gas -retarder.
The soil in crawl spaces shall be covered with a continuous layer of minimum 6 -mil (0.15 mm)
polyethylene soil -gas -retarder. The ground cover shall be lapped not less than 12 inches (305 mm) at
joints and shall extend to all foundation walls enclosing the crawl space area.
AF103.5.3 Vent pipe.
A plumbing tee or other approved connection shall be inserted horizontally beneath the sheeting and
connected to a 3- or 4 -inch -diameter (76 or 102 mm) fitting with a vertical vent pipe installed through
the sheeting. The vent pipe shall be extended up through the building floors, and terminate not less
than 12 inches (305 mm) above the roof in a location not less than 10 feet (3048 mm) away from any
window or other opening into the conditioned spaces of the building that is less than 2 feet (610 mm)
below the exhaust point, and 10 feet (3048 mm) from any window or other opening in adjoining or
adjacent buildings.
AF103.6 Passive subslab depressurization system.
In basement or slab -on -grade buildings, the following components of a passive subslab depressurization
system shall be installed during construction.
AF103.6.1 Vent pipe.
A minimum 3 -inch -diameter (76 mm) ABS, PVC or equivalent gas -tight pipe shall be embedded vertically
into the subslab aggregate or other permeable material before the slab is cast. A "T" fitting or equivalent
method shall be used to ensure that the pipe opening remains within the subslab permeable material.
Alternatively, the 3 -inch (76 mm) pipe shall be inserted directly into an interior perimeter drain tile loop
or through a sealed sump cover where the sump is exposed to the subslab aggregate or connected to it
through a drainage system.
The pipe shall be extended up through the building floors, and terminate not less than 12 inches (305
mm) above the surface of the roof in a location not less than 10 feet (3048 mm) away from any window
or other opening into the conditioned spaces of the building that is less than 2 feet (610 mm) below the
exhaust point, and 10 feet (3048 mm) from any window or other opening in adjoining or adjacent
buildings.
AF103.6.2 Multiple vent pipes.
In buildings where interior footings or other barriers separate the subslab aggregate or other gas -
permeable materia', each area shall be fitted with an individual vent pipe. Vent pipes shall connect to a
single vent that terminates above the roof or each individual vent pipe shall terminate separately above
the roof.
AF103.7 Vent pipe drainage.
Components of the radon vent pipe system shall be installed to provide positive drainage to the ground
beneath the slab or soil -gas -retarder.
AF103.8 Vent pipe accessibility.
Radon vent pipes shall be accessible for future fan installation through an attic or other area outside the
habitable space.
Exception: The radon vent pipe need not be accessible in an attic space where an approved roof -top
electrical supply is provided for future use.
AF103.9 Vent pipe identification.
Exposed and visible interior radon vent pipes shall be identified with not less than one label on each
floor and in accessible attics. The label shall read: "Radon Reduction System."
AF103.10 Combination foundations.
Combination basement/crawl space or slab-on-grade/crawl space foundations shall have separate radon
vent pipes installed in each type of foundation area. Each radon vent pipe shall terminate above the roof
or shall be connected to a single vent that terminates above the roof.
AF103.11 Building depressurization.
Joints in air ducts and plenums in unconditioned spaces shall meet the requirements of Section M1601.
Thermal envelope air infiltration requirements shall comply with the energy conservation provisions in
Chapter 11. Fireblocking shall meet the requirements contained in Section R302.11.
AF103.12 Power source.
To provide for future installation of an active submembrane or subslab depressurization system, an
electrical circuit terminated in an approved box shall be installed during construction in the attic or
other anticipated location of vent pipe fans. An electrical supply shall be accessible in anticipated
locations of system failure alarms.
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