[HISTORY: Adopted by the Town Board of the Town of Lima 12-11-2000 by L.L. No.
1-2000. Amendments noted where applicable.]
GENERAL REFERENCES
Building construction and fire prevention — See Ch. 92.
This chapter shall be known as "Radon Control Methods."
It is the purpose of this chapter to promote the public health,
safety and general welfare and to provide construction standards to
resist the entry of radon and prepare buildings for post-construction
radon mitigation.
For the purpose of this chapter, the terms used shall be defined
as follows:
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.
A continuous membrane of six-mil (0.15 mm) polyethylene or
other equivalent material used to retard the flow of soil gases into
a building.
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.
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.
A system designed to achieve lower subslab 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.
The following construction techniques are intended to resist
radon entry and prepare the building for post-construction radon mitigation,
if necessary.
A.
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, a minimum of four inches (102
mm) thick. The aggregate shall consist of material that will pass
through a two-inch (51 mm) sieve and be retained by a one-fourth-inch
(6.4 mm) sieve.
(2)
A uniform layer of sand (native or fill) a minimum of four 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.
B.
Ground cover. A minimum six-mil (0.15 mm) [or three-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 sheeting shall cover the entire floor area
with separate sections of sheeting lapped at least 12 inches (305
mm). The sheeting shall fit closely around any pipe, wire or other
penetrations of the material. All punctures or tears in the material
shall be sealed or covered with additional sheeting.
D.
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.
E.
Concrete joints. All 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,
F.
Condensate drains. Condensate drains shall be trapped or routed through
nonperforated pipe to daylight.
G.
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 designated to accommodate
the vent pipe. Sumps used as a floor drain shall have a lid equipped
with a trapped inlet.
H.
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 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.
I.
Damp-proofing. The exterior surfaces of portions of concrete and
masonry block walls below the ground surface shall be damp-proofed.
K.
Ducts. Ductwork passing through a crawl space 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.
L.
Crawl space floors. Openings around all penetrations through floors
above crawl spaces shall be caulked or otherwise filled to prevent
air leakage.
M.
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.
In buildings with crawl space foundations, the following components
of a passive submembrane depressurization system shall be installed
during construction, except for buildings in which an approved mechanical
crawl space ventilation system or other equivalent system is installed.
A.
Ventilation. Crawl spaces shall be provided with vents to the exterior
of the building.
B.
Ground cover. The soil in crawl spaces shall be covered with a continuous
layer of minimum six-mil (0.15 mm) polyethylene ground cover. The
ground cover shall be lapped a minimum of 12 inches (305 mm) at joints
and shall extend to all foundation walls enclosing the crawl space
area.
C.
Vent pipe. A plumbing tee or other approved connection shall be inserted
horizontally beneath the sheeting and connected to a three- or four-inch
diameter (76 mm or 102 mm) fitting with a vertical vent pipe installed
through the sheeting. The vent pipe shall be extended up through the
building floors, terminate at least 12 inches (305 mm) above the roof
in a location at least 10 feet (3048 mm) away from any window or other
opening into the conditioned spaces of the building that is less than
two feet (610 mm) below the exhaust point, and 10 feet (3048 mm) from
any window or other opening in adjoining or adjacent buildings.
In basement or slab-on-grade buildings, the following components
of a passive subslab depressurization system shall be installed during
construction.
A.
Vent pipe.
(1)
A minimum of three-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 three-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.
(2)
The pipe shall be extended up through the building floors, terminate
at least 12 inches (305 mm) above the surface of the roof in a location
at least 10 feet (3048 mm) away from any window or other opening into
the conditioned spaces of the building that is less than two feet
(610 mm) below the exhaust point, and 10 feet (3048 mm) from any window
or other opening in adjoining or adjacent buildings.
B.
Multiple vent pipes. In buildings where interior footings or other
barriers separate the subslab aggregate or other gas-permeable material,
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.
C.
Vent pipe drainage. All components of the radon vent pipe system
shall be installed to provide positive drainage to the ground beneath
the slab or soil-gas-retarder.
D.
Vent pipe accessibility.
E.
Vent pipe identification. All exposed and visible interior radon
vent pipes shall be identified with at least one label on each floor
and in accessible attics. The label shall read: "Radon Reduction System."
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.
The construction shall include joints in air ducts and plenums
in unconditioned spaces, thermal envelope air infiltration requirements
and fire stopping.
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
shaft also be accessible in anticipated locations of system failure
alarms.
