PASSIVE RADON CONTROL SYSTEM IN
CRAWL SPACE FOR NEW CONSTRUCTION

NOTES:

1. INSTALL A LENGTH OF 3” OR 4” DIAMETER PERFORATED ORAN
TLE HORIZONTALLY BENEATH THE SHEETING AND CONNECT
TO THE “T" FITTING WITH THE VERTICAL STANOPIPE THROUCH
THE SOW-GAS-RETARDER MEMBRANE. THIS HORIZONTAL PIPE
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 CODES: VENTS SHALL BE OPEN TO THE
EXTERIOR AND BE OF NONCLOSEABLE DESIGN.

3. CIRCUITS SHOULO BE A MINIMUM 15 AMP, TIS VOLT.

FLASHING

EXHAUST (10° FROM OPENINGS INTO

CONDITIONED SPACES OF BUILDING)
12"_MIN. ABOVE ROOF

!
|

a

[ ROOF BRACE

SEAL AROUND
FLOOR PENETRATIONS ——}

_

FOR FUTURE INSTALLATION

eB
we
ATTIC
im
L| JOIST -_ 4

INTERIOR PARTITION —el | Z exeermen, sanction ox’
FOR FUTURE INSTALLATION

LIVING AREA OF VENT FAN: NOTE 3.

f A ELECTRICAL JUNCTION BOX

i

FLOORING 7

er

OF WARNING DEVICE: NOTE 3.

JOIST

T

PS
PN

SUPPORT i
STRAPPING 7

CAP BLOCK OR OTHER SEA
ON HOLLOW BLOCK WALLS

WALL AND AROUND PENETRATIONS (MIN. 6-ML
POLYETHYLENE SHEETING OR EQUIVALENT)

PERFORATED DRAN
TRE: NOTE 1

LEVEL

CRAWL SPACE
NOTE 2

[+—— 3-4" DIA VENT PPe
(PVC OR EQUIVALENT)

4 ——-

SEAL MEMBRANE AROUND

SOIL-GAS-RETARDER MEMBRANE SEALED AGANST

PIPE PENETRATION
ADJOINING SHEETS OF

MEMBRANE OVERLAPPED
AND SEALED 1 -

PVC T-FIRTING (OR EQUIVALENT)
TO SUPPORT VENT PPE


United States Indoor Environments Division EPA 402-95012
Environmental Protection Office of Radiation and May 1995
Agency Indoor Air

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.goviiaq



PASSIVE SUB-SLAB DEPRESSURIZATION RADON
CONTROL SYSTEM FOR NEW CONSTRUCTION

NOTES:

|. ALL CONCRETE SLABS THAT COME IN CONTACT WITH THE GROUND SHALL
BE LAD 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

EXHAUST (10'FROM OPENINGS INTO.
CONDITIONED SPACES OF BUILDING)

{ 12" MIN. ABOVE ROOF

FLASHING

oa
a

ROOF BRACE

ATTIC

ELECTRICAL JUNCTION BOX

CONDENSATION DRANS DOWNWARD INTO THE GROUND BENEATH THE
SLAB OR SOIL-GAS-RETARDER MEMBRANE.
5. CIRCUITS SHOULD BE A MINIMUM 15 AMP, 115 VOLT. 7
ck
at
JOIST aad | +
ELECTRICAL JUNCTION BOX
FOR FUTURE INSTALLATION
LIVING AREA [/——_] OF VENT FAN: NOTE 5.

INTERIOR PARTITION ——»

FLOORING mi

FOR FUTURE INSTALLATION
OF WARNING DEVICE: NOTE 5.

WATERPROOF SEALANT APPLIED
TO EXTERIOR WALLS

a 2 SOIL-GAS-RETARDER MEMBRANE (MIN.
GRADE ° * 6-MIL POLYETHYLENE SHEETING OR
LEVEL EQUIVALENT); OVERLAP SEAMS 12" MIN.

SEAL OPENINGS IN SLAB AND
AROUND PENETRATIONS: NOTE 3

JOIST [= suport
STRAPPING
> —— CAP BLOCK OR OTHER SEAL
: ON HOLLOW BLOCK WALLS | 3"-4" DIA VENT PIPE

(PVC OR EQUIVALENT)

| SLAB: NOTE 2

MIN. 4" THICK LAYER
OF GAS PERMEABLE
SEAL MATERIAL: NOTE 1

PVC T-FITTING (OR EQUIVALENT)
TO SUPPORT VENT PIPE


ADDITIONAL COMPONENTS REQUIRED FOR ACTIVATION EXHAUST (10° FROM OPENINGS INTO

OF PASSIVE SUB-SLAB DEPRESSURIZATION OR { CONDITIONED SPACES’ OF BUILDING)
CRAWLSPACE RADON CONTROL SYSTEM 12* MN. ABOVE ROOF
NOTES: ;
1. INSTALL THE VENT FAN IN THE VERTICAL RUN OF THE VENT PIPE. [~ FLASHING.
THE SIZE AND AR MOVEMENT CAPACITY OF THE VENT FAN SHALL

BE SUFFICIENT TO CREATE AND MAINTAIN A PRESSURE FIELD
BENEATH THE SLAB OR CRAWLSPACE MEMBRANE THAT IS LOWER

THAN THE PRESSURE ABOVE THE SLAB OR MEMBRANE. 4]
2. ALL POSITIVELY PRESSURED PORTIONS OF THE VENT PIPE AND

FAN SHALL BE LOCATED OUTSIDE THE HABITABLE SPACE OF

THE BUILDING. |
3. PROVIDE A VISIBLE OR AUDIBLE WARNING SYSTEM TO

ALERT THE BUILDING OCCUPANT IF THERE IS A LOSS FAN COUPLING TO PIPE

OF PRESSURE OR AIR FLOW IN THE VENT PIPE.
. ROOF BRACE
= t

rae FAN: NOTE if +
e ATTIC & NOTE 2
> JOIST tr
[ ELECTRICAL
LIVING AREA JUNCTION BOX
i SYSTEM FAILURE

+

INTERIOR PARTITION DEVICE: NOTE 3.

FLOORING im

—

GRADE
LEVEL