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A Presentation of Primary Research before
the American Association of Radon Scientists and Technologists
2014 International Radon Symposium
Gordon T. Satoh, M.S.
Managing Director of Commercial Markets
S.W.A.T. Enterprises, LLC
OVERVIEW
Radon concentrations can be elevated within walls
Simple treatments can help address localized high levels
How this
research
came to be
Concrete
Masonry Units
and Block Wall
Construction
Measuring
Radon
within Voids
Comparing
Inexpensive
Treatment
Methods
Analysis
and
Discussion
Implications
of these
Findings
Why Conduct Research?
Out of Curiousity
A Corentium Digital Radon Monitor was provided
to the researcher for review and consideration
The size of the monitor allowed for sampling in a
variety of new locations
By Accident
During one sampling event the researcher dropped
the monitor within the void of a wall built of
construction masonry units
After sixteen days of thought , the researcher came
up with a method of retrieving the monitor.
Why Conduct Research?
WHAT DID THE MONITOR READ?
42 pCi/L (1,554
3
Bq/m )
Over 10 times the United States action threshold
of 4.0 pCi/L (148 Bq / m3) !
Could there be a gradient in the void?
Can inexpensive treatments address the levels?
Concrete Masonry Units
Facts Regarding CMUs
Existed as early as the mid-1870s as cement block
Called cinder blocks – mixed cinders with Portland
Nominally 16” x 8” x 8” (41 cm x 20 cm x 20 cm)
Lightweight (~40 lbs / 18 kg) and Inexpensive
Used for exterior and interior block walls
Subject Single Family Residence
Exterior walls constructed of CMUs
Voids were left hollow - some had Fiberglas® batts
Active Soil Depressurization System was operating
Measuring Radon within Voids
Corentium Digital Radon Monitor
From Corentium, based in Oslo, Norway
Passive diffusion chamber with silicon diode
Not yet approved in U.S. as a certified device
Comparative Study:
Corentium Device 1.78 (65.86 Bq/m3) (7 day exposure)
AirChek AC Device 2.1 ± 0.3 pCi/L (77.1 ± 11.1 Bq/m3)
Methodology
Pre-marked line with harness to lower device
Seven day exposure period
Replicates on three elevations
Measuring Radon within Voids
Radon Gradient Exhibited Within CMU Void in Block Wall
45
Average Air Concentration of Radon (pCi/L)
42.3
40
35
31.0
30
Average pCi/L
25
23.2
20
15.9
15
11.8
10.7
10
5
0
24
48
60
72
Height Above Grade (Inches)
80
88
Application – Treatment Methods
Diphenylmethane diisocyanate foam
Two penetrations per void, four per CMU
Dow Chemical “Great Stuff” Big Gap Filler
Seven second actuation per 3/8” penetration
Low pressure vessel is safer but use ventilation
Owens Corning Foamular 150 Board
R-5 insulation board is easily cut to size
Sealed to the top of the CMUs
Loctite PL Advance Polyurethane Construction Adhesive
Board is weighted to prevent gaps from forming
Excess adhesive is smoothed and removed
Application – Treatment Methods
Indoor Air Radon Concentration (pCi/L )Post Application of Treatments
INDOOR AIR RADON CONCENTRATION (PCI/L)
3.5
3
2.5
Board Cap
2
Block Fill
Linear (Board
Cap)
1.5
Linear (Block Fill)
1
0.5
0
0
1
2
3
4
MEASUREMENTS (NON-CHRONOLOGICAL)
5
6
Analysis and Discussion
Radon gas within CMU voids decreased in
concentration with increasing elevation above
grade
The momentum of decrease is greater at lower
elevations versus upper elevations above grade
The decrease is non-linear in nature, however
data are insufficient to determine if this is a
uniform function
Active Soil (sub-slab) Depressurization System
may have influenced the gradient
Analysis and Discussion
Visually the two treatment types possessed
similar distributions, favoring insulation board
The two sample t test was selected to assess the
distribution of data points between the two
treatments
Alpha was set at 0.05
Variance was defined as unequal
Data sets were considered to be unpooled
Sample size for each treatment was n = 5
Analysis and Discussion
Component
Mean (pCi/L)
Standard Deviation
(pCi/L)
Sample Size (n)
Alpha (α)
Variance
Treatment 1
Block Fill
Treatment 2
2.49
Insulation Board
2.36
0.62
0.64
5
0.05
0.38
5
0.05
0.41
Null hypothesis is there is not a significant difference
between the two treatment methods
Two tailed p value was calculated to be 0.76
0.76 > 0.05 therefore the null hypothesis is valid
Implications of these Findings
Localized radon concentrations may be elevated
above average indoor radon screening values
Radon concentrations in CMU voids may be
considerably higher
Inexpensive methods for treating CMU voids
make treatment practical in addition to PSD/ASD
This study is a platform for further investigations
Radon professionals can conduct primary
research at a relatively low cost
Mr. Jamey Gelina – President, SWAT Enterprises, LLC
Mr. Aaron Jones – Vice President of Operations
Mr. Joseph Gelina – Vice President of Development
Halvor Woien of Corentium AS, Oslo, Norway
Stephanie Satoh – Researcher’s Spouse
(for allowing research to be conducted in our home)
Gordon T. Satoh, M.S.
Managing Director of Commercial Markets
S.W.A.T. Enterprises, LLC