United States
Environmental Protection
Agency
Indoor Environments Division
Office of Radiation and
Indoor Air
EPA 402-95012
May 1995
Passive Radon Control System for New Construction
Architectural Drawings
of:
1) Passive radon control system
2) Crawlspace radon control system
3) Additional fan for active system
for one and two -family dwellings
These architectural drawings are intended for use by
architects, home builders, designers, radon mitigators and
others interested in the installation of passive radon control
systems in one and two -family dwellings. For more
information on radon and radon-resistant new construction
call 1-800-55RADON or see the EPA web page:
www.epa.gov/iaq
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PASSIVE SUB-SLAB DEPRESSURIZATION RADON
CONTROL SYSTEM FOR NEW CONSTRUCTION
NOTES:
1. ALL CONCRETE SLABS THAT COME IN CONTACT WITH THE GROUND SHALL
BE LAID OVER A GAS PERMEABLE MATERIAL MADE UP OF EITHER A MINIMUM
4" THICK UNIFORM LAYER OF CLEAN AGGREGATE, OR A MINIMUM 4" THICK
UNIFORM LAYER OF SAND, OVERLAIN BY A LAYER OR STRIPS OF MANUFACTURED
MATTING DESIGNED TO ALLOW THE LATERAL FLOW OF SOIL GASES.
2. ALL CONCRETE FLOOR SLABS SHALL BE DESIGNED AND CONSTRUCTED
IN ACCORDANCE WITH LOCAL BUILDING CODES. ADDITIONAL REFS-'
AMERICAN CONCRETE INSTITUTE PUBLICATIONS, "ACI302.1R" &
"ACI332R", OR THE POST TENSIONING INSTITUTE MANUAL, "DESIGN
AND CONSTRUCTION OF POST-TENSIONED SLABS ON GROUND".
3. ALL OPENINGS, GAPS AND JOINTS IN FLOOR AND WALL ASSEMBLIES IN
CONTACT SOIL OR GAPS AROUND PIPES, TOILETS, BATHTUBS OR
DRAINS PENETRATING THESE ASSEMBLIES SHALL BE FILLED OR CLOSED
WITH MATERIALS THAT PROVIDE A PERMANENT AIR-TIGHT SEAL. SEAL
LARGE OPENINGS WITH NON-SHRINK MORTAR, GROUTS OR EXPANDING
FOAM MATERIALS AND SMALLER GAPS WITH AN ELASTOMERIC JOINT
SEALANT, AS DEFINED IN ASTM C920-87.
4. VENT PIPES SHALL BE INSTALLED SO THAT ANY RAINWATER OR
CONDENSATION DRAINS DOWNWARD INTO THE GROUND BENEATH THE
SLAB OR SOIL-GAS-RETARDER MEMBRANE.
5. CIRCUITS SHOULD BE A MINIMUM 15 AMP, 115 VOLT.
EXHAUST (10' FROM OPENINGS INTO
CONDITIONED SPACES OF BUILDING)
12" MIN. ABOVE ROOF
JOIST
LIVING AREA
INTERIOR PARTITION
FLOORING —i
JOIST
GRADE
LEVEL
CAP BLOCK OR OTHER SEAL
ON HOLLOW BLOCK WALLS
WATERPROOF SEALANT APPLIED
TO EXTERIOR WALLS
SOIL-GAS-RETARDER MEMBRANE (MIN.
6-MIL POLYETHYLENE SHEETING OR
EQUIVALENT); OVERLAP SEAMS 12" MIN.
-SEAL OPENINGS IN SLAB AND
AROUND PENETRATIONS; NOTE 3
ELECTRICAL JUNCTION BOX
FOR FUTURE INSTALLATION
OF VENT FAN: NOTE 5.
ELECTRICAL JUNCTION BOX
FOR FUTURE INSTALLATION
OF WARNING DEVICE: NOTE 5.
3"-4" DIA. VENT PIPE
(PVC OR EQUIVALENT)
SLAB; NOTE 2
MIN. 4" THICK LAYER
OF GAS PERMEABLE
MATERIAL; NOTE 1
PVC T-FITTING (OR EQUIVALENT)
TO SUPPORT VENT PIPE
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ADDITIONAL COMPONENTS REQUIRED FOR ACTIVATION
OF PASSIVE SUB-SLAB DEPRESSURIZATION OR
CRAWLSPACE RADON CONTROL SYSTEM
NOTES:
1. NSTALL THE VENT FAN IN THE VERTICAL RUN OF THE VENT PIPE.
THE SIZE AND AIR MOVEMENT CAPACITY OF THE VENT FAN SHALL
BE SUFFICIENT TO CREATE AND MAJNTAN A PRESSURE FIELD
BENEATH THE SLAB OR CRAWLSPACE MEMBRANE THAT IS LOWER
THAN THE PRESSURE ABOVE THE SLAB OR MEMBRANE.
2. ALL POSITIVELY PRESSURED PORTIONS OF THE VENT PPE AND
FAN SHALL BE LOCATED OUTSIDE THE HABITABLE SPACE
THE BUILDING.
3. PROVIDE A VISIBLE OR AUDIBLE WARNING SYSTEM TO
ALERT THE BUILDING OCCUPANT IF THERE IS A LOSS
OF PRESSURE OR AIR FLOW IN THE VENT PIPE.
EXHAUST (1C1 FROM OPENWGS WTO
CONDITIONED SPACES' OF BUILDING)
12" MIN. ABOVE ROOF
FAN COUPLING TO PPE
ROOF BRACE
FAN; NOTE 1
& NOTE 2
ELECTRICAL
JUNCTION BOX
LIVING AREA
SYSTEM FAILURE
DEVICE: NOTE 3.
INTERIOR PARTITION
FLOORING
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PASSIVE RADON CONTROL SYSTEM IN
CRAWL SPACE FOR NEW CONSTRUCTION
NOTES
1. (STALL A LENGTH OF 3" OR 4" DIAMETER PERFORATED DRAIN
TLE HORIZONTALLY BENEATH THE SHEETWG AND CONNECT
TO THE "T" FITTWG WITH THE VERTICAL STANOPPE THROUGH
THE SOL-GAS-RETAROER MEMBRANE. THE HORIZONTAL PPE
SHOULD NORMALLY BE PLACED PARALLEL TO THE LONG
DIMENSION OF THE HOUSE AND SHOULD EXTEND NO CLOSER
THAN 6 FEET TO THE FOUNDATION WALL.
2. VENTILATE CRAWLSPACES IN CONFORMANCE WITH
LOCAL COOES; VENTS SHALL BE OPEN TO THE
EXTERIOR AND BE OF NONCLOSEABLE DESIGN.
3. CIRCUITS SHOULD BE A MNMUM 15 AMP. 115 VOLT.
EXHAUST (W FROM OPEMNGS WTO
, CONDITIONED SPACES OF BUB.DNG)
12" MM. ABOVE ROOF
WTERIOR PARTITION
LIVING AREA
SEAL AROUND
FLOOR PENETRATIONS
SUPPORT
STRAPPING
3"-4" DIA. VENT
(PVC OR EQUIVALENT)
CAP BLOCK OR OTHER SEAL
ON HOLLOW BLOCK WALLS
CRAWL SPACE
NOTE 2
ELECTRICAL JUNCTION BOX
FOR FUTURE NSTALLATWN
OF VENT FAN; NOTE 3.
ELECTRICAL JUNCTION BOX
FOR FUTURE INSTALLATION
OF WARMNG DEVICE: NOTE 3.
GRADE
LEVEL
r
SOL-GAS-RETAROER MEMBRANE SEALED AGAINST
WALL AND AROUND PENETRATIONS (MN. 6-ML
POLYETHYLENE SHEETING OR EQUIVALENT)
PERFORATED DRAW
TIE; NOTE 1
-SEAL MEMBRANE AROUND
PPE PENETRATION
ADJOtiNC SHEETS OF
MEMBRANE OVERLAPPED
AND SEALED —,
PVC T-FUTING (OR EQUIVALENT)
TO SUPPORT VENT PPE
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