Current through Register Vol. 49, No. 13, September 23, 2024
Subpart 1.
Gas permeable material
preparation.
A gas-permeable material shall be placed on the prepared
subgrade under all floor systems.
Subp.
2.
Soil-gas membrane installation.
A soil-gas membrane shall be placed on top of the gas-permeable
material prior to placing a floor on top of or above the soil. The soil-gas
membrane shall cover the entire floor area. Separate sections of membrane must
be lapped at least 12 inches (305 mm). The membrane shall fit closely around
any penetration of the membrane to reduce the leakage of soil gases. All
punctures or tears in the soil-gas membrane shall be repaired by sealing and
patching the soil-gas membrane with the same kind of material, maintaining a
minimum 12-inch (305 mm) lap.
Subp.
3.
"T" fitting.
A "T" fitting shall be installed beneath the soil-gas membrane
with a minimum of 10 feet of perforated pipe connected to any two openings of
the "T" fitting, or by connecting the two openings to the interior drain tile
system. The third opening of the "T" fitting shall be connected to the vent
pipe. The perforated pipe or drain tile and the "T" fitting shall be the same
size as the vent pipe. All connections to the "T" fitting shall be tight
fitting.
Subp. 4.
Potential entry routes.
Potential entry routes for radon gas shall be sealed according
to this subpart, as applicable.
A.
Floor openings. Floor openings around bathtubs, showers, water
closets, pipes, wires, or other objects that penetrate the soil-gas membrane
and the concrete slab or other floor systems, shall be sealed.
B.
Concrete joints. All control
joints, isolation joints, construction joints, or any other joints in the
concrete slab, or the joint between the concrete slab and a foundation wall,
shall be sealed. All gaps and joints shall be cleared of all loose material
prior to sealing.
C.
Foundation walls. Penetrations of all foundation wall types shall
be sealed. Joints, cracks, or other openings around all penetrations of both
exterior and interior surfaces of foundation walls shall be sealed.
(1) Hollow block masonry foundation walls
shall be constructed with either:
(a) a
continuous course of solid masonry at or above the exterior ground
surface;
(b) one course of masonry
grouted solid at or above the exterior ground surface; or
(c) a solid concrete beam at or above the
finished exterior ground surface.
(2) When a brick veneer or other masonry
ledge is installed, the masonry course immediately below the veneer or ledge
shall be solid or filled.
D.
Unconditioned crawl spaces.
All penetrations through floors or walls into unconditioned crawl spaces shall
be sealed. Access doors into unconditioned crawl spaces shall be gasketed.
Crawl space ventilation shall be provided according to part
1303.2400.
E.
Sumps. A
sump connected to interior drain tile may serve as the termination point for
the vent pipe, if the sump cover is sealed or gasketed and designed to
accommodate the vent pipe. The sump pump water discharge pipe shall have a
backflow preventer installed.
Subp.
5.
Vent pipes.
A.
Single vent pipe. The vent pipe shall be primed and glued at all
fittings and shall extend up from the radon control systems collection point to
a point terminating a minimum of 12 inches (305 mm) above the roof. The vent
pipe shall be located at least 10 feet (3,048 mm) away from any window or other
opening into the conditioned spaces of the building. Vent pipes routed through
unconditioned spaces shall be insulated with a minimum of R-4 insulation. Vent
pipes within the conditioned envelope of the building shall not be
insulated.
B.
Multiple vent
pipes. In buildings where interior footings or other barriers separate
the gas-permeable material into two or more areas, each area shall be fitted
with an individual radon control system in accordance with item A, or connected
to a single radon gas vent pipe terminating above the roof in accordance with
item A.
C.
Vent pipe
drainage. All components of the radon gas vent pipe system shall be
installed to provide drainage to the ground beneath the soil-gas
membrane.
D.
Vent pipe
accessibility. Radon gas vent pipes shall be provided with space around
the vent pipe for future installation of a fan. The space required for the
future fan installation shall be a minimum of 24 inches in diameter, centered
on the axis of the vent pipe, and shall extend a minimum distance of 3 vertical
feet.
Exception: Accessibility to the radon gas vent
pipe is not required if the future fan installation is above the roof system
and there is an approved rooftop electrical supply provided.
E.
Vent pipe identification. All
radon gas vent pipes shall be identified with at least 1 label on each story
and in attics and crawl spaces. The label shall read: "Radon Gas Vent
System."
F.
Combination
foundations. Combination basement/crawl space or slab-on grade/crawl
space foundations shall have separate radon gas vent pipes installed in each
type of foundation area. Each radon gas vent pipe shall terminate above the
roof or shall be connected to a single vent pipe that terminates above the
roof.
Subp. 6.
Power source.
A power source consisting of an electrical circuit terminating
in an approved electrical box shall be installed during construction in the
anticipated location of the vent pipe fan to allow for the future installation
of a fan into a passive radon control system to make the system an active radon
control system. The power source shall not be installed in any conditioned
space, basement, or crawl space.
Statutory Authority: MS s
326B.02;
326B.101;
326B.106
