AEERL-P-329
RADON DIAGNOSIS AND ABATENENT
«V
IN
RESIDENTIAL DWELLINGS
BY
A- B. CRAIG
DEPUTY DIRECTOR
AIR AND ENER6Y ENGINEERING RESEARCH-LABORATORY
U- S- ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK, NC
U.'S. Environments! Protootl»n
Library, Room 2404 PM-211-A
401 M Str»ei, S.W.
DO 30480
CFD
Presented At
Builders Association of
Somerset and Morris
Somerset, NJ
March 4, 1987
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EPA - ORD
INDOOR RADON REDUCTION DEVELOPMENT/DEMONSTRATION PROJECT
OBJECTIVE; TO DEVELOP AND DEMONSTRATE LOW-COST RADON
REDUCTION MEASURES
- EXISTING HOMES (FIRST PRIORITY) AND
NEW CONSTRUCTION
- CONSIDER ALL SUBSTRUCTURE TYPES,
NATIONAL IN SCOPE
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DRIVING FORCE FOR SOIL GAS ENTRY
0 HOUSES NATURALLY TEND TO BE AT A LOWER PRESSURE THAN THE
SURROUNDING SOIL, SO RADON-CONTAINING SOIL GAS IS SUCKED
INTO THE HOUSE
0 FLOW OF SOIL GAS INTO HOUSE IS INCREASED BY ANY ADDITIONAL
DEPRESSURIZATION OF THE HOUSE (OR BASEMENT)., WHICH CAN BE
CAUSED BY:
NATURAL THERMAL STACK EFFECT (MOST PRONOUNCED IN
COLD WEATHER)
' THERMAL BYPASSING (FACILITATES THE STACK EFFECT)
APPLIANCES WHICH DRAW AIR OUT OF THE BASEMENT OR
HOUSE (FIREPLACES, FURNACES/ CLOTHES DRIERS,
EXHAUST FANS)
- OPEN WINDOWS ON JUST THE DOWNWIND SIDE OF THE HOUSE
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Brick venter
Top void In block wall
Concrete blocks
Void In concrete block
Block pores
and holes
Settling cracks and
cold joints
Wall/
floor joints
Mortar joint cracks
Block pores and holes
Openings beside
utility pipes
Mortar joint crack
Slab
Agqreoate
Entry routes for soil gas into a concrete block basement home
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CHECKLIST OF POSSIBLE RADON ENTRY ROUTES
A- SOIL GAS ENTRY THROUGH FOUNDATION WALL (BASEMENT HOUSES).
1. UNCLOSED VOIDS IN THE TOP COURSE OF HOLLOW BLOCKS
2* CRACKS IN BLOCKS, AND IN MORTAR JOINTS BETWEEN
BLOCKS; CRACKS IN POURED CONCRETE WALLS
3* OPENINGS IN WALLS AROUND UTILITY PENETRATIONS
(WATER, SEWER, FUEL OIL/ ETC*)
4. OTHER HOLES IN WALLS (E-G*/ DEFECTS IN BLOCKS)
5* PORES IN HOLLOW BLOCKS (CINDER BLOCK GENERALLY
MORE POROUS THAN CONCRETE BLOCK)
6- JOINT BETWEEN THE WALL OF THE LOWER LEVEL AND THE
SLAB OF AN ADJOINING HIGHER LEVEL IN A SPLIT LEVEL
HOUSE
7* FIREPLACE STRUCTURES BUILT INTO WALLS
NoTg: FOR HOLLOW BLOCK WALLS/ THE ABOVE LIST APPLIES
NOT ONLY TO EXTERIOR PERIMETER WALLS/ BUT ALSO
TO ANY INTERIOR WALLS WHICH PENETRATE THE SLAB
AND REST ON FOOTINGS*
B. SOIL 6AS ENTRY THROUGH SLABS AND FLOORS
1* SETTLING CRACKS IN SLABS
2* COLD JOINTS IN SLABS
3* JOINT BETWEEN THE SLAB AND THE WALLS (INCLUDING
INTERIOR AS WELL AS EXTERIOR WALLS)
4- OPENINGS IN SLAB AROUND ANY UTILITY PENETRATIONS
(WATER/ SEWER/ ETC*)
5* JOINT BETWEEN THE SLAB AND ANY OTHER INDIVIDUAL
PENETRATIONS THROUGH THE SLAB
6* ANY HOLLOW OBJECTS PENETRATING THE SLAB AND OPEN
TO THE HOUSE
5
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7- OTHER HOLES IN SLAB EXPOSING EARTH
8* HOLES IN FLOORING OVER CRAWL SPACES
9* URTRAPPED FLOOR DRAINS WHICH CONNECT TO DRAIN TILES
(OR TRAPPED FLOOR DRAINS WITH RODDING EYE HISSING)
10. SUMPS (GENERALLY CONNECTED TO DRAIN TILES BENEATH
- THE SLAB OR AROUND THE EXTERIOR OF THE FOOTINGS)
C- SOIL GAS ENTRY THROUGH OTHER ROUTES
! LEAKAGE OF CRAWL SPACE AIR INTO CIRCULATING HOUSE
AIR IN CENTRAL HVAC SYSTEM
D- RADON ENTRY WITH WELL WATER
! ANY WATER USAGE APPLIANCE IN HOUSES HAVING WELLS
WITH ELEVATED RADON CONCENTRATIONS IN THE WATER
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RADON HIT
N
AT1VES
I
HOUSE VENTILATION
o PRINCIPLE: REMOVE THE RADON ONCE IT HAS ENTERED THE
HOUSE (BY DILUTION WITH OUTDOOR AIR)
o SPECIFIC TECHNIQUES:
- NATURAL VENTILATION
- FORCED VENTILATION (USING FAN)
* HEAT RECOVERY VENTILATOR (HRV, OR AIR-TO~AIR
HEAT EXCHANGER)
o EFFECTIVENESS DEPENDS UPON INCREASE IN VENTILATION RATE
ACHIEVED; REDUCTIONS UP TO 901 HAVE BEEN REPORTED-
o ADVANTAGES
* NATURAL, FORCED VENTILATION EASY TO IMPLEMENT,
NO (OR LIMITED) INSTALLATION COST
- 'CONVENTIONAL* TECHNOLOGY
- AT LEAST MODERATE REDUCTIONS REASONABLY ASSURED
o DISADVANTAGES
* NATURAL, FORCED VENTILATION MIGHT NOT BE PRACTICALLY
APPLICABLE (AND WOULD CAUSE SIGNIFICANT ENERGY PEN-
ALTIES) DURING SOME MONTHS IN COLD AND HOT CLIMATES
- SOME ENEGY PENALTY, EVEN WITH A HRV
* MECHANISMS BY WHICH HRV'$ ACHIEVE REDUCTIONS NOT YET
FULLY UNDERSTOOD (MIGHT BE MORE THAN SIMPLE DILUTION);
NOT CLEAR THAT VERY NIGH REDUCTIONS CAN ALWAYS BE
ASSURED*
o PRACTICAL CONSIDERATIONS
- ASSURANCE OF HIGH LEVELS OF REDUCTION WOULD REQUIRE
A HRV (FIXED, HIGH INCREASE IN VENTILATION RATE);
PRACTICAL ABILITY OF OPERATE YEAR'AROUND WOULD ALSO
REQUIRE A HRV
* MUST ASSURE THAT HRV's REMAIN BALANCED OVER TIME
(FRESH AIR INTAKE/HOUSE AIR EXHAUST)
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tADOi MITIGATION ALTERNATIVES
B* SEALING OF SOIL GAS ENTRY ROUTES
o PRINCIPLE: PREVENT SOIL GAS FROM GETTING INTO HOUSE
o SPECIFIC TECHNIQUE: PERMANENTLY SEAL ALL OPENINGS
BETWEEN THE SLAB (OR FLOOR) AND THE SOIL, AND BETWEEN'
THE FOUNDATION WALL AND THE SOIL (E*G*, USING SEALANTS,
COATINGS, MEMBRANES)- COVER SUMPS* REMOVABLE PLUG IN
UNTRAPPED FLOOR DRAINS-
o EFFECTIVENESS DEPENDS UPON COMPLETENESS OF SEALING JOB,
IMPORTANCE OF THE ENTRY ROUTES SEALED; REDUCTIONS UP TO
901 HAVE BEEN REPORTED*
o ADVANTAGES
" TOTALLY PASSIVE, IDEALLY NO OPERATING COST
- POTENTIALLY THE MOST AESTHETIC APPROACH
o DISADVANTAGES
- ENTRY ROUTES TYPICALLY NUMEROUS AND INACCESSIBLE;
IT WOULD BE TECHNICALLY VERY DIFFICULT, AND VERY
EXPENSIVE, TO COMPLETELY SEAL AN EXISTING HOME
- CRACKS IN THE SEAL CAN RE"OCCUR AS HOUSE SHIFTS
OVER THE YEARS
o* PRACTICAL CONSIDERATIONS
- MAJOR, REASONABLY ACCESSIBLE OPENINGS SHOULD ALWAYS
BE SEALED; SOME HIGHLY SITE-SPECIFIC REDUCTION WILL
LIKELY BE ACHIEVED
* SEALING WILL OFTEN BE A NECESSARY PART OF OTHER
MITIGATION APPROACHES
- SEALING OF MAJOR OPENINGS MIGHT SOMETIMES BE SUFFI-
CIENT, BY ITSELF, TO REDUCE SLIGHTLY-ELEVATED HOUSES
DOWN TO 'SAFE* LEVELS; SEALING WILL PROBABLY RARELY,
IF EVER, BE A COST-EFFECTIVE MEASURE BY ITSELF FOR
REDUCING HIGH-LEVEL HOMES DOWN TO SAFE LEVELS*
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UDOM MITIGATION ALTERNATIVES
C- ACTIVE SOIL VENTILATION
o PRINCIPLE: USE FANS TO DRAM OR FORCE SOIL GAS AWAY FROM
THE VICINITY OF THE HOUSE BEFORE IT CAN ENTER-
CAUSE THE SOIL (OR, E.G., THE HOLLOW BLOCK
VOID NETWORK) TO BE AT A PRESSURE LOWER THAN
THAT IN THE HOUSE/ SO THAT ANY GAS MOVEMENT
IS FROM THE HOUSE OUTWARD INTO THE SOIL*
0 SPECIFIC TECHNIQUES:
- HOLLOW BLOCK WALL VENTILATION
- SUB-SLAB VENTILATION
* WALL VENTILATION PLUS SUB-SLAB VENTILATION
- DRAIN TILE SUCTION
TAP INTO LINE TO EXTERNAL SOAK-AWAY
COVER AND VENT INTERNAL SUMP
o REDUCTIONS WELL ABOVE 90Z (TO 99+Z) CAN GENERALLY BE
ACHIEVED, ALTHOUGH THE INSTALLATION COST FOR ACHIEVING
SUCH HIGH REDUCTIONS CAN VARY SIGNIFICANTLY DEPENDING
UPON SITE-SPECIFIC FACTORS*
o ADVANTAGES:
- POTENTIAL FOR HIGH LEVEL OF REDUCTION IN HOST CASES
- POTENTIAL FOR MODERATE COST IN MANY CASES
o DISADVANTAGES:
- CAN BE DIFFICULT/EXPENSIVE TO ADEQUATELY VENTILATE
ALL SOIL GAS ENTRY ROUTES IN SOME CASES
- IS DEVELOPMENTAL (NOT "CONVENTIONAL*)
- SOME ACTIVE SOIL VENTILATION TECHNIQUES CAN BE
DIFFICULT/EXPENSIVE TO INSTALL IN FINISHED BASEMENTS
- WILL BE SOME CONTINUING OPERATING AND MAINTENANCE
COSTS
o PRACTICAL CONSIDERATIONS
- WILL LIKELY ALWAYS HAVE TO BE CONSIDERED FOR HIGH-
LEVEL HOUSES g
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Connections fb
other walls
Home afr
J through settling
*~ cracks, cold joints.
utility openings
->.. ;.;.Soil gas f.-'i-ri.v
Sub-slib vtntlUtlon
10
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Connection to other walls
Seal top voids
3XT »
rnr
Seal major nortar cracks and holes
in wall
Home air through block pores, unsealed
cracks, and holes
Utility pipe
oate
Block wall suction system
11
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Seal top voids
Exhaust
Fan
Soil gas
Seal major mortar cracks and holes
In wall
Hone air through block pores, unsealed
cracks, and holes
Sheet metal baseboard duct
Baseboard suction system
12
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Riser connecting.
drain tile to tan
Condensale
Capped riser
add water to trap
§ g,'--^.XEsisting drain tile
lp\ circling the house
N-Water tap to prevent air!
-Water tap to prevent air from
being drawn up from soak iway
Drain tile ventilation (with soakamy)
13
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tircfina the house
--
« SSISi3^S5ilS33«^^^^3 ^
. " *.! 1 .*
. v "*"! "* .**: ./?
:-:^:-
^^
'--.»i
Drain tile ventilation (with sump)
14
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Floorplen for the "Ranch * Style
(Split Level)
S r
Kitchen
Lav
Family
Room
Bedroom
0
H
Master
Bedroom
Dining Room
E
Living Room
Bedroom
Heat risers
\
Siao on Grade
Translie subslab
heating ducts
Basement
UP
Chimney
15
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hop Board
Expansion Joint
(with Homosole Fill)
Concrete Slab
Sheetrock
1/2" Ply wood
2x4 Stud Wall
2x4 Sill
Solid L - Block
8* Concrete Block
(Hollow Core)
. ^^^^ i _ i
Full section of slab-on-grade
20
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Hop Board
Sheetrock
Concrete Slab
1/2" Ply wood
2x4 Stud Wall
2x4 Sill
6' Concrete Block
(Hollow Core)
\iiiimii
21
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Fen
Undergrade
Pipes
jj
Famtty Room
Lav.
Utility
Garage
22
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RADON MITIGATION ALTERHATIVES
D- PASSIVE SOIL VENTILATION
o PRINCIPLE;
DRAW SOIL GAS AWAY FROM THE VICINITY OF THE
HOUSE BEFORE IT CAN ENTER/ WITHOUT USING A
FAN- SUCTION is DRAWN ON A SUB-SLAB PIPING
NETWORK BY THE THERMAL STACK EFFECT IN A
RISER WHICH PENETRATES THROUGH THE ROOF/ AND
BY REDUCED PRESSURES AT THE ROOFLINE*
0 SPECIFIC TECHNIQUE:
- SUB'SLAB VENTILATION
EFFECTIVENESS WILL BE HIGHLY DEPENDENT UPON THE EXTENT
OF THE SUB-SLAB PIPING NETWORK/ WEATHER CONDITIONS/ AND
OTHER FACTORS*
o ADVANTAGES:
- TOTALLY PASSIVE/ NO OPERATING COST
o DISADVANTAGE:
~ SUCTION DRAWN BY THIS SYSTEM IS SMALL/ THUS/ AN
EXTENSIVE PERFORATED PIPING NETWORK MUST BE LAID
UNDER THE SLAB TO ACHIEVE ADEQUATE TREATMENT* CAN
BE EXPENSIVE TO RETROFIT SUCH A PIPING NETWORK INTO
AN EXISTING HOUSE*
o PRACTICAL CONSIDERATIONS:
* WOULD BE MOST APPLICABLE IN NEW CONSTRUCTION/ OR
WHERE A SUB-SLAB PIPING NETWORK ALREADY EXISTS/ OR
WHERE THE EXISTING SLAB MUST BE TORN OUT FOR OTHER
REASONS*
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I*'*-..*.-..?.
TIRBINE VENTILATOR
NEW 6" § VENT STACK
INSTALL MEW ROOF JACK £ SEAL
EXIST. ROOF
ATTIC SPACE
iFIRESTOP
SEAL PER CODE
CEILINS
FUR t ENCLOSE WHERE EXPOSED
IN FINISHED AREA
IFIRESTOP
ISEAL PER CODE
FLOOR JOIST
NEW VENT STACK,
SCH <»0 6" 0 PVC,
FIELD LOCATE ON INTERIOR OF HOUSE,
HAINTAIN A 10* MINI. HDRZ. DISTANCE
BETWEEN STACK C NEAREST WIND
OBSTRUCTION
6** TO V REDUCER
NEW CONC. TO HATCH EXIST.
EXIST. FLOOR
ICW V PERF. VENT PIPE
PASSIVE SUB-SLAB VENTILATION SYSTEM
From "General Remedial Action Details for Radon Gas Hitlsatlon"
Pennsylvania Depertnent of Envlronnental Resources (Hay 1985)
24
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RADON MITIGATION ALTERNATIVES
£ HOUSE PRESSUR1ZATION
o PRINCIPLE: KEEP THE HOUSE AT A PRESSURE HIGHER THAN THE
SURROUNDING SOIL, SO THAT GAS MOVEMENT IS
FROM THE HOUSE OUTWARD INTO THE SOIL-
0 SPECIFIC TECHNIQUE:
* BLOW AIR INTO THE HOUSE (OR INTO THE BASEMENT) TO
INCREASE THE PRESSURE
o EFFECTIVENESS DEPENDS UPON A NUMBER OF FACTORS (AMOUNT OF
AIR SUPPLIED, EXTENT OF SEALING OF PRESSURIZED REGION
FROM THE OUTDOORS AND FROM THE REMAINDER OF THE HOUSE)-
o ADVANTAGE:
- POTENTIAL FOR HIGH LEVEL OF RADON REDUCTION
o DISADVANTAGES:
- DIFFICULT TO MAINTAIN ELEVATED PRESSURE UNDER NORMAL
CIRCUMSTANCES DUE TO NUMEROUS ROUTES BY WHICH AIR
CAN LEAK OUT (E.G., BAROMETRIC DAMPER IN FURNACE
FLUE)
- ENERGY PENALTY IF AIR BLOWN IN FROM OUTDOORS
- NIGHT MAKE HOUSE FEEL DRAFTY; MIGHT REQUIRE INCON-
VENIENCES (E.G., CLOSING OFF FIREPLACE)
o PRACTICAL CONSIDERATIONS:
- TECHNIQUE IS DEVELOPMENTAL; MIGHT OFFER POTENTIAL
ULTIMATELY, BUT PRACTICAL PROBLEMS MUST BE OVERCOME
FIRST
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RADON HITIGAT1QH ALTERNATIVES
F. AVOIDANCE OF HOUSE DEPRESSURIZATION
o PRINCIPLE:
TAKE STEPS TO REDUCE HOUSE DEPRESSURIZATION
(AND HENCE SOIL GAS INFLUX) CAUSED BY HOUSE-
HOLD ACTIVITIES AND BY WEATHER-
o SPECIFIC TECHNIQUES (EXAMPLES):
- CRACK WINDOW WHEN FIREPLACE IN USE
* OPEN WINDOWS ON BOTH SIDES OF THE HOUSE
* PROVIDE OUTDOOR SOURCE OF COMBUSTION AIR FOR
FURNACES/ OTHER APPLIANCES
- CLOSE MAJOR OPENINGS BETWEEN FLOORS (REDUCE
THERMAL BYPASSING)
o EFFECTIVENESS HIGHLY SITE SPECIFIC; CAN BE VERY HIGH
FOR SHORT PERIODS IN SOME CASES*
o ADVANTAGES:
~ SOME OF THESE STEPS CAN BE IMPLEMENTED EASILY
* CAN HAVE MAJOR SHORT-TERM BENEFITS IN SOME CASES
-o DISADVANTAGES:
- SOME OF THESE STEPS LESS EASY TO IMPLEMENT
- YEAR-AROUND BENEFITS NOT WELL DOCUMENTED
o PRACTICAL CONSIDERATIONS
- WHERE STEPS CAN BE IMPLEMENTED EASILY/ THOSE
STEPS SHOULD BE TAKEN; SHORT-TERM BENEFITS CAN
BE SIGNIFICANT-
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RADON MITIGATION ALTERNATIVES
HOUSE AIR CLEANERS
o PRINCIPLE: REMOVE RADON PROGENY (OR RADON) FROM
THE HOUSE AIR
o SPECIFIC TECHNIQUES:
FILTERS, ELECTROSTATIC PRECIPITATORS TO REMOVE
PARTICLES (RADON PROGENY) FROM CIRCULATING HOUSE
AIR
* SORPT10N UNITS TO REMOVE RADON GAS
o EFFECTIVENESS AT REDUCING GROSS WORKING LEVEL CAN BE
MODERATE TO HIGH; EFFECT ON WORKING LEVEL OF UNATTACHED
PROGENY IS AN ISSUE WITH PARTICLE REMOVAL DEVICES
o ADVANTAGES:
CAN GIVE MODERATE AND HIGHER WORKING LEVEL
REDUCTIONS
- GENERALLY 'CONVENTIONAL* TECHNOLOGY; DO NOT
REQUIRE SIGNIFICANT MODIFICATIONS TO THE HOUSE
o DISADVANTAGE:
- PARTICLE REMOVAL DEVICES MIGHT INCREASE THE
AMOUNT OF UNATTACHED PROGENY; HEALTH RISKS
UNCLEAR
o PRACTICAL CONSIDERATIONS:
- EFFECTS OF PARTICLE REMOVAL DEVICES ON UNATTACHED
PROGENY, AND THE RESULTING HEALTH EFFECTS/ MUST BE
CLARIFIED BEFORE THESE DEVICES CAN BE RECOMMENDED*
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APPRQXIHAT
ON MITIGATION
I
TECHNIQUE
HOUSE VENTILATION
1- NATURAL
2- FORCED
3. HRV
SEALING
4- COMPREHENSIVE
SEALING
APPROXIMATE
I REDUCTION
UP TO 90
UP TO 90
UP TO 90*
Low TO 90
INSTALLED COST ($)
BY BY
HOMEOWNER CONTRACTOR
0
Low
ANNUAL
OPERATING
COST
TO 150
400-1,500
4 TIMES HEATING
COSTS-
UP TO $100 * 4
TIMES HEATING
COSTS*
UP TO $100 *
iCTlVE SOIL VENTILATION
5- WALL VENTILATION
** SINGLE POINT
- BASEBOARD DUCT
6. SUB-SLAB
VENTILATION
7- DRAIN TILE
SUCTION
UP
UP
UP
UP
TO
TO
TO
TO
99*
99*
90-99
98*
Low TO
MODERATE
100-400
200-600
200-500
Low TO
>10,000
2,500*
5,000*
2,000*
100-300 1,200
PASSIVE SOIL VENTILATION
8- SUB-SLAB
VENTILATION
HOME PRESSURIZATION
9* HOUSE PRESSURIZATION
AVOID DEPRESSURIZATION
10. AVOID DEPRESSURI-
ZATION
REMOVAL
1-6 TIMES
HEATING COSTS'
'NONE*
$150
$150
$150
$150
NONE
CLEANERS
11* PARTICLE
DEVICES
12- 6AS SORPTION
DEVICES
WELL WATER TREATMENT
13- WATER TREATMENT
DEVICES *
PERFORMANCE/COSTS HIGHLY VARIABLE, SITE-SPECIFIC (OR OTHERWISE UNABLE
TO ESTIMATE AT THIS TIME).
28
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29
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30
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e
u
31
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flop Board
Expansion Joint
(With Homosole Fill)
Sheetrock
Concrete Slab
\
\7^V- . > :-:::T:N::>:;:::-:::-.X
/^'^f<^"'\\^ ;i;i:i;i;:-::>
1/2" Ply wood
2x4 Stud Wall
2x4 Sill
Solid L-Block
8" Concrete Block
(Hollow Core)
32
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Hop Board
Expansion Joint
(with Homosolc Fill)
Concrete Slab
Sheetrock
1/2" Ply wood
2x4 Stud Wall
2x4 Sill
Solid L - Block
8* Concrete Block
(Hollow Core)
33
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36
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37
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39
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Radon Risk Evaluation Chart
Eninwud number of
pCi/l WL lung cancer deaths
Out to rvdon utposur*
(ewi of 1000)
200
100
40
20
10
0.2
1
0.5
0.2
0.1
0.05
0.02
0.01
0.005
0.001
440770
270630
120380
60210
30120
1350
730
313
13
Comparable
exposure levels
1000 times
average outdoor
level
100 times
average indoor
level
100 times
average outdoor
level
10 times average
indoor level
10 times
average outdoor
level
Average indoor
level
Average outdoor
level
Comparable
risk
More than 60 times
' non-smoker risk
, 4 pack-a-day
smoker
20,000 chest
x-rays per year
pack-a-day
smoker
>1 pack-a-day
smoker
$s&
H»»5 times
non-smoker risk
1200 chest x-rays
per year
Non-smoker
* o{ °Yi"9
from lung cancer
|1II|^20 chest x-rays
$ per year
40
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