RADON REDUCTION AND RADON-RESISTANT
CONSTRUCTION DEMONSTRATIONS
IN NEW YORK STATE
New York State Energy Research and Development Authority
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The New York State Energy Research and Development Authority (Energy
Authority) is responsible for the development and use of safe, dependable, renewable
and economic energy sources and conservation technologies. It sponsors energy
research, development and demonstration (RD&D) projects and financing programs
designed to help utilities and other private companies fund certain energy-related projects.
The Energy Authority is a public benefit corporation which was created in 1975 by the
New York State Legislature.
In working toward these goals, the Energy Authority sponsors research, development
and demonstration projects in two major program areas: Energy Efficiency and Economic
Development, and Energy Resources and Environmental Research.
Under its financing program, the Energy Authority is authorized to issue tax-exempt
bonds to finance certain electric or gas facilities and special energy projects for private
companies.
The Energy Authority also has responsibility for constructing and then operating
facilities for the disposal of low-level radioactive wastes produced in New York State. The
generators of these wastes ultimately will bear the costs of the construction of these
facilities.
A 13-member board of directors governs the Energy Authority, with William D. Cotter,
Commissioner of the State Energy Office, serving as Chairman of the Board and Chief
Executive Officer. In/in L. White, President of the Energy Authority, manages its
programs, staff and facilities.
The Energy Authority derives its basic RD&D revenues from an assessment levied on
the intrastate sales of New York State's investor-owned electric and gas utilities.
Additional RD&D funds come from the investment of retained earnings, as well as from an
annual contribution from the New York Power Authority.
The Energy Authority's RD&D program is also supported by funds from a variety of
cosponsors, including utilities, universities, industries, private engineering and scientific
research firms, local governments, and State and Federal agencies.
For further information on the Energy Authority's programs, contact the Department of
Communications, New York State Energy Research and Development Authority, phone
(5.18) 465-6251, extension 272.
State of New York Energy Research and Development Authority
Mario M. Cuomo, William D. Cotter,
Governor Chairman
Irvin L White,
President
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RADON REDUCTION
AND RADON-RESISTANT CONSTRUCTION
DEMONSTRATIONS IN NEW YORK STATE
Final Report
Prepared for
THE NEW YORK STATE
ENERGY RESEARCH AND DEVELOPMENT AUTHORITY
Program Manager
Joseph E. Rizzuto, P.E.
and
THE U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, D.C. 20460
Michael Osborne
Project Officer
Prepared by
THE FLEMING GROUP
6310 Fly road
East Syracuse, New York 13057
954-EEED-BES-87
Energy Authority
Report 91-11 February 1991
Printed on Recycled Paper
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NOTICE
This report was prepared by The Fleming Group in the course of
performing work contracted for and sponsored by the U.S. Environ-
mental Protection Agency and and the New York State Energy
Research and Development Authority (hereafter the "Sponsors"). The
opinions expressed in this report do not necessarily reflect those of the
Sponsors or the State of New York and reference to any specific
product, service, process or method does not necessarily constitute an
implied or expressed recommendation or endorsement of same.
Further, the Sponsors and the State of New York make no warranties
or representations, expressed or implied, as to the fitness for particular
purpose, merchantability of any product, apparatus or service or the
usefulness, completeness or accuracy of any processes, methods or
other information contained, described, disclosed or referred to in this
report. The Sponsors and the State of New York and the contractor
make no representation that the use of any product, apparatus, process,
method or other information will not infringe privately owned rights
and will assume no liability for any loss, injury, or damage resulting
from, or occurring in connection with, the use of information contained,
described, disclosed, or referred to in this report.
First Printing: October 1991
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ABSTRACT
The United States Environmental Protection Agency (EPA) and the New York State Energy
Research and Development Authority (NYSERDA) cosponsored a project in New York State to
demonstrate radon mitigation techniques in existing homes with elevated radon concentrations and
to test radon-resistant construction techniques in new houses. This research project was divided into
two tasks.
The first part of the existing home evaluation demonstrated radon mitigation techniques in
homes where the indoor radon concentrations exceeded the EPA guideline of 4 pCi/L. Results
demonstrated that sealing all accessible foundation penetrations in the basement was an effective way
to reduce the radon concentration, although not below the EPA guideline, and that sealing aids in
the effectiveness of an active depressurization system. Active depressurization systems were usually
successful in meeting the EPA guideline. The footing drain, sub-slab, and basement walls were all
successfully depressurized using a standard technique after grab samples or radon sniffing techniques
were used to identify the radon entry source(s). Basement pressurization also proved to be an
effective method of reducing the radon level below the EPA guideline at one site. Water aeration
systems were effective at mitigating radon from residential water supplies although the system tested
was large and noisy. Activated charcoal filters adsorbed the radon and eventually became an
unacceptable source of gamma radiation.
The second part of the existing home evaluation involved the inspecton of homes where radon
mitigation systems were installed in 1984 as part of an earlier NYSERDA/Niagara Mohawk Power
Corporation (NMPC) project. It was found that new systems and techniques, such as in-line
centrifugal fans, were generally superior to the earlier methods using axial computer-type fans.
Polyurethane caulk was found to be in good condition; butyl caulk, on the other hand, had
deteriorated.
In the new house task, a radon-resistant system was developed for integration into a house
during construction. This system included sealing foundation floors, sealing concrete block foundation
walls, and passive sub-slab ventilation. The results indicated that this integrated radon mitigation
system reduced the radon concentration in new test houses below that of control houses, but the
reduction was not usually sufficient to meet the EPA guideline. The passive ventilation system was
then enhanced by the addition of an in-line centrifugal fan, thereby producing an active
depressurization system. Active depressurization was always successful at meeting the EPA guideline.
Building a house with an integrated radon mitigation system was one-third of the cost of retrofitting
a new home with an active depressurization system.
111
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ACKNOWLEDGMENTS
This final report is the result of the dedicated efforts of many individuals and organizations
including the following:
COSPONSOR:
COSPONSOR:
PRIME CONTRACTOR:
DIAGNOSTICIAN:
MITIGATION CONTRACTOR:
GEOLOGIST:
SCREENING AND SUPPORT:
United States Environmental Protection Agency
Michael Osbome, Project Officer
New York State Energy Research and Development
Authority
Joseph Rizzuto, Program Manager
W.S. Fleming and Associates, Inc.
Ian Nitschke, Principal Investigator, and
co-author
Michael Clarkin, Project Manager, and
co-author
Wayne Clark, Project Manager, New Houses,
and co-author
Robert E. Hough, co-author
Paul Anderson
P. Richard Bums
Paul Remington
Camroden Associates
Terry Brennan
Evenshire Co. Ltd.
Edwin Evans
Wade Evans
William Lilley
New York State Department of Health
Charles Kunz
Karim Rimawi
Typing and report production were provided by Kathaleen Underwood, Rosemarie DePalma and
Valerie Gilbert, The Fleming Group. Other individuals who have contributed substantially to the
project include Susan Galbraith of Cogito Technical Services, Jerry Lowrey of Lpwrey Engineering
and, of course, all the patient and understanding homeowners. Special appreciation is extended
to all those who were involved in the project, but are not specifically mentioned.
IV
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CONTENTS
SECTION Page
SUMMARY S-l
1. INTRODUCTION 1-1
2. DEMONSTRATING RADON REDUCTION TECHNIQUES
IN EXISTING HOMES 2.0-1
2.0 Overview 2.0-1
2.1 House AR-01 2.1-1
2.2 House AR-04 2.2-1
2.3 House AR-05 2.3-1
2.4 House AR-09 2.4-1
2.5 House AR-16 2.5-1
2.6 House AR-17 2.6-1
2.7 House AR-19 2.7-1
2.8 House AR-20 2.8-1
2.9 House OP-01 2.9-1
2.10 House OP-03 2.10-1
2.11 House OP-05 2.11-1
2.12 House OP-06 2.12-1
2.13 House OP-09 2.13-1
2.14 House OP-13 2.14-1
2.15 House OP-16 ' 2.15-1
2.16 House OP-17 2.16-1
2.17 Conclusions 2.17-1
3. ASSESSING PREVIOUSLY INSTALLED MITIGATION
TECHNIQUES IN EXISTING HOMES 3.0-1
3.0 Overview 3.0-1
3.1 House NM-02 3.1-1
3.2 House NM-05 3.2-1
3.3 House NM-12 3.3-1
3.4 House NM-16 3.4-1
3.5 House NM-19 3.5-1
3.6 House NM-21 3.6-1
3.7 House NM-26 3.7-1
3.8 House NM-28 3.8-1
3.9 House NM-29 3.9-1
V
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CONTENTS (continued)
SECTION
3.10
3.11
3.12
3.13
3.14
3.15
House NM-31
House NM-37
House NM-41
House NM-51
House NM-56
Conclusions
3.10-1
3.11-1
3.12-1
3.13-1
3.14-1
3.15-1
4. DEMONSTRATING RADON-RESISTANT NEW CONSTRUCTION
TECHNIQUES 4.1-1
4.1 Overview 4.1-1
4.2 House ON-01 (Control) 4.2-1
4.3 House ON-02 (Control) 4.3-1
4.4 House ON-03 (Control) 4.4-1
4.5 House ON-04 (Control) 4.5-1
4.6 House ON-05 (Control) 4.6-1
4.7 House ON-06 4.7-1
4.8 House ON-07 4.8-1
4.9 House ON-08 4.9-1
4.10 House ON-09 4.10-1
4.11 House ON-10 4.11-1
4.12 House ON-11 4.12-1
4.13 House ON-12 4.13-1
4.14 House ON-13 4.14-1
4.15 House ON-14 4.15-1
4.16 House ON-15 4.16-1
4.17 House ON-16 4.17-1
4.18 House ON-17 4.18-1
4.19 House ON-18 4.19-1
4.20 House ON-19 4.20-1
4.21 House ON-20 4.21-1
4.22 New House Demonstration: Conclusions 4.22-1
Appendix A. DETAILED RESULTS FROM DEMONSTRATING RADON REDUCTION
TECHNIQUES IN EXISTING HOMES A-l
Appendix B. DETAILED RESULTS FROM ASSESSING PREVIOUSLY INSTALLED
MITIGATION TECHNIQUES IN EXISTING HOUSES B-l
VI
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ILLUSTRATIONS
2.1-1
2.2-1
2.3-1
2.4-1
2.5-1
2.6-1
2.7-1
2.8-1
2.9-1
2.10-1
2.11-1
2.12-1
2.13-1
2.14-1
2.15-1
2.16-1
3.1-1
3.2-1
3.3-1
3.4-1
3.5-1
3.6-1
3.7-1
3.8-1
3.9-1
3.10-1
3.11-1
3.12-1
3.13-1
3.14-1
4.2-1
4.2-2
4.2-3
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
House
AR-01
AR-04
AR-05
AR-09
AR-16
AR-17
AR-19
AR-20
OP-01
OP-03
OP-05
OP-06
OP-09
OP-14
OP-16
OP-17
NM-02
NM-05
NM-12
NM-16
NM-19
NM-21
NM-26
NM-28
NM-29
NM-31
NM-37
NM-41
NM-51
NM-56
ON-01
ON-01
House
ON-01
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
Comparison
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
of Radon
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
Measurements
by
by
by
by
by
by
by
by
by
by
by
by
by
by
Phase
Phase
Phase
Phase
Phase
Phase
Phase
Phase
Phase
Phase
Phase
Phase
Phase
Phase
(Control) Foundation Floor Plan
(Control) Radon Concentrations:
Closed, Basement Open, and Second Roor Open
(Control) Radon Concentrations:
Phase 0 and Phase 3
4.3-1 House ON-02 (Control) Foundation Roor Plan
4.3-2 House ON-02 (Control) Radon Concentrations:
Phase 0 and Phase 3
4.4-1 House ON-03 (Control) Foundation Roor Plan
2.1-4
2.2-4
2.3-5
2.4-5
2.5-4
2.6-4
2.7-3
2.8-3
2.9-5
2.10-4
2.11-4
2.12-3
2.13-3
2.14-3
2.15-4
2.16-3
3.1-3
3.2-3
3.3-3
3.4-2
3.5-2
3.6-3
3.7-3
3.8-2
3.9-3
3.10-3
3.11-3
3.12-2
3.13-2
3.14-2
4.2-4
4.2-6
4.2-7
4.3-3
4.3-5
4.4-4
VI1
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ILLUSTRATIONS (continued)
Figure
4.4-2 House ON-03 (Control) Radon Concentrations:
Phase 0 Phase 3 4.4-6
4.4-3 House ON-03 (Control) Radon Concentrations: Phase 3A 4.4-7
4.5-1 House ON-04 (Control) Foundation Floor Plan 4.5-4
4.5-2 House ON-04 (Control) Radon Concentrations:
With Exterior Vent Alternately Open (Phase 0) and Closed
(Phase 0') 4.5-6
4.5-3 House ON-04 (Control) Radon Concentrations:
Phase 0 and Phase 3 4.5-7
4.5-4 House ON-04 (Control) Radon Concentrations: Phase 3A 4.5-8
4.6-1 House ON-05 (Control) Foundation Floor Plan 4.6-4
4.6-2 House ON-05 (Control) Radon Concentrations:
Phase 0 and Phase 3 4.6-6
4.6-3 House ON-05 (Control) Radon Concentrations: Phase 3A 4.6-7
4.7-1 House ON-06 Foundation Floor Plan 4.7-3
4.8-1 House ON-07 Foundation Floor Plan 4.8-3
4.8-2 House ON-07 Radon Concentrations: Phase 0 and Phase 1 4.8-5
4.9-1 House ON-08 Foundation Floor Plan 4.9-3
4.10-1 House ON-09 Foundation Floor Plan 4.10-4
4.10-2 House ON-09 Radon Concentrations: Phase 2 , 4.10-6
4.10-3 House ON-09 Radon Concentrations:
Phase 0, Phase l,Phase 2, and Phase 3 4.10-7
4.11-1 House ON-10 Foundation Floor Plan 4.11-3
4.12-1 House ON-11 Foundation Floor Plan 4.12-4
4.12-2 House ON-11 Radon Concentrations:
Phase 0, Phase 1, Phase 2, and Phase 3 4.12-6
4.13-1 House ON-12 Foundation Floor Plan 4.13-4
4.13-2 House ON-12 Radon Concentrations: Phase 0 4.13-6
4.13-3 House ON-12 Radon Concentrations: Phase 0 and Phase 1 4.13-7
4.13-4 House ON-12 Radon Concentrations:
Phase 0, Phase 1, Phase 2, and Phase 3 4.13-8
VI11
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ILLUSTRATIONS (continued)
4.14-1 House ON-13 Foundation Floor Plan 4.14-3
4.14-2 House ON-13 Radon Concentrations: Phase 0 4.14-5
4.14-3 House ON-13 Radon Concentrations:
Phase 0, Phase 1, Phase 2, and Phase 3 4.14-6
4.15-1 House ON-14 Foundation Floor Plan 4.15-3
4.16-1 House ON-15 Foundation Floor Plan 4.16-4
4.16-2 House ON-15 Radon Concentrations: Phase 2 4.16-6
4.16-3 House ON-15 Radon Concentrations: Phase 1 4.16-7
4.16-4 House ON-15 Radon Concentrations:
Phase 0, Phase 1, Phase 2, and Phase 3 4.16-8
4.17-1 House ON-16 Foundation Floor Plan 4.17-3
4.17-2 House ON-16 Radon Concentrations: Phase 2 4.17-5
4.17-3 House ON-16 Radon Concentrations: Phase 0 and Phase 3 4.17-6
4.18-1 House ON-17 Foundation Roor Plan 4.18-3
4.18-2 House ON-17 Radon Concentrations:
Phase 0, Phase 1, Phase 2, and Phase 3 4.18-5
4.19-1 House ON-18 Foundation Roor Plan 4.19-4
4.19-2 House ON-18 Radon Concentrations: Phase 0 4.19-6
4.19-3 House ON-18 Radon Concentrations: Phase 0 4.19-7
4.19-4 House ON-18 Radon Concentrations:
Phase 0, Phase 1, Phase 2, and Phase 3 4.19-8
4.19-5 House ON-18 Radon Concentrations:
Phase 3A, Phase 3B, and Phase 3C 4.19-9
4.20-1 House ON-19 Foundation Roor Plan 4.20-4
4.20-2 House ON-19 Radon Concentrations: Phase 0 4.20-6
4.20-3 House ON-19 Radon Concentrations:
Phase 0, Phase 1, Phase 2, and Phase 3 4.20-7
4.21-1 House ON-20 Foundation Roor Plan 4.21-3
4.21-2 House ON-20 Radon Concentrations:
Phase 0, Phase 1, Phase 2, and Phase 3 4.21-5
IX
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TABLES
Table Page
1.1 Overall Project Goals 1-2
1.2 Specific Objectives 1-3
1.3 List of Tasks and Sub-Tasks 1-4
1.4 Goals of Task I: Demonstrate Techniques in Existing Houses 1-5
1.5 Goals of Task II: Demonstrate Techniques in New Houses 1-6
2-1 Results of Initial Survey Performed by the Bureau of
Environmental Radiation Protection New York State
Department of Health 2.0-2
4.2-1 House ON-01 (Control) Building Characteristics 4.2-3
4.2-2 House ON-01 (Control) Installed Mitigation Techniques 4.2-5
4.2-3 House ON-01 (Control) Integrated Radon Concentrations 4.2-8
4.3-1 House ON-02 (Control) Building Characteristics 4.3-2
4.3-2 House ON-02 (Control) Installed Mitigation Techniques 4.3-4
4.3-3 House ON-02 (Control) Integrated Radon Concentrations 4.3-6
4.4-1 House ON-03 (Control) Building Characteristics 4.4-3
4.4-2 House ON-03 (Control) Installed Mitigation Techniques 4.4-5
4.4-3 House ON-03 (Control) Integrated Radon Concentrations 4.4-8
4.5-1 House ON-04 (Control) Building Characteristics 4.5-3
4.5-2 House ON-04 (Control) Installed Mitigation Techniques 4.5-5
4.5-3 House ON-04 (Control) Integrated Radon Concentrations 4.5-9
4.6-1 House ON-05 (Control) Building Characteristics 4.6-3
4.6-2 House ON-05 (Control) Installed Mitigation 4.6-5
4.6-3 House ON-05 (Control) Integrated Radon Concentrations 4.6-8
4.7-1 House ON-06 Building Characteristics 4.7-2
4.7-2 House ON-06 Installed Mitigation Techniques 4.7-4
4.7-3 House ON-06 Integrated Radon Concentrations 4.7-5
4.S-1 House ON-07 Building Characteristics 4.8-2
4.8-2 House ON-07 Installed Mitigation Techniques 4 g-4
4.8-3 House ON-07 Integrated Radon Concentrations 4.8-6
4.9-1 House ON-08 Building Characteristics 4_9_2
4.9-2 House ON-08 Installed Mitigation Techniques 4.9-4
4.9-3 House ON-08 Integrated Radon Concentrations 4 9.4
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TABLES (continued)
Table Page
4.10-1 House ON-09 Building Characteristics 4.10-3
4.10-2 House ON-09 Installed Mitigation Techniques 4.10-5
4.10-3 House ON-09 Integrated Radon Concentrations 4.10-8
4.11-1 House ON-10 Building Characteristics 4.11-2
4.11-2 House ON-10 Installed Mitigation Techniques 4.11-4
4.11-3 House ON-10 Integrated Radon Concentrations 4.11-5
4.12-1 House ON-11 Building Characteristics 4.12-3
4.12-2 House ON-11 Installed Mitigation Techniques 4.12-5
4.12-3 House ON-11 Integrated Radon Concentrations 4.12-9
4.13-1 House ON-12 Building Characteristics 4.13-3
4.13-2 House ON-12 Installed Mitigation Techniques 4.13-5
4.13-3 House ON-12 Integrated Radon Concentrations 4.13-9
4.14-1 House ON-13 Building Characteristics 4.14-2
4.14-2 House ON-13 Installed Mitigation Techniques 4.14-4
4.14-3 House ON-13 Integrated Radon Concentrations 4.14-7
4.15-1 House ON-14 Building Characteristics 4.15-2
4.15-2 House ON-14 Installed Mitigation Techniques 4.15-4
4.15-3 House ON-14 Integrated Radon Concentrations 4.15-5
4.16-1 House ON-15 Building Characteristics 4.16-3
4.16-2 House ON-15 Installed Mitigation Techniques 4.16-5
4.16-3 House ON-15 Integrated Radon Concentrations 4.16-9
4.17-1 House ON-16 Building Characteristics 4.17-2
4.17-2 House ON-16 Installed Mitigation Techniques 4.17-4
4.17-3 House ON-16 Integrated Radon Concentrations 4.17-7
4.18-1 House ON-17 Building Characteristics 4.18-2
4.18-2 House ON-17 Installed Mitigation Techniques 4.18-4
4.18-3 House ON-17 Integrated Radon Concentrations 4.18-6
4.19-1 House ON-18 Building Characteristics 4.19-3
4.19-2 House ON-18 Installed Mitigation Techniques 4.19-5
4.19-3 House ON-18 Integrated Radon Concentrations 4.19-10
4.20-1 House ON-19 Building Characteristics 4.20-3
4.20-2 House ON-19 Installed Mitigation Techniques 4.20-5
XI
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TABLES (continued)
Table Page
4.20-3 House ON-19 Integrated Radon Concentrations 4.20-8
4.21-1 House ON-20 Building Characteristics 4.21-2
4.21-2 House ON-20 Installed Mitigation Techniques 4.21-4
4.21-3 House ON-20 Integrated Radon Concentrations 4.21-6
4.22-1 Results from New Construction Test Sites 4.22-3
4.21-2 Results from New Construction Control Sites 4.22-4
Xll
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SUMMARY
Growing concern about the health risks associated with exposure to indoor radon, a
radioactive gas found in varying amounts in nearly all houses, has underscored the need for
dependable radon reduction methods in existing and newly constructed homes. Responding to this
need, the United States Environmental Protection Agency (EPA) and the New York State Energy
Research and Development Authority (NYSERDA) cosponsored a project in New York State to
demonstrate radon reduction techniques in homes with elevated radon concentrations, and to test
radon^resistant construction techniques in new houses.
A primary goal of this research project was to demonstrate the effectiveness of radon
reduction techniques in homes containing indoor radon concentrations of more than the current EPA
guideline of 4 pCi/L. In addition to demonstrating new radon reduction techniques, the effectiveness
and durability of previously implemented techniques was assessed. These radon reduction techniques
were previously implemented in homes during a project cosponsored by NYSERDA and the Niagara
Mohawk Power Corporation (NMPC) in 1983 and 1984. Additionally, radon-resistant construction
techniques were demonstrated in homes under construction to gather information and to provide
guidance for houses being built in areas with a risk of high radon levels. To reach these goals, the
work was divided into the following tasks:
Task I, Subtask 1.
Task I, Subtask 2.
Demonstrating Radon Mitigation Techniques in Homes Containing Indoor
Radon Concentrations Exceeding 4 pCi/L.
Assessing the Effectiveness and Durability of Previously Installed Radon
Reduction Techniques.
Task II.
Demonstrating Radon-Resistant New Construction Techniques.
S-l
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TASK I, SUBTASK 1
DEMONSTRATING RADON MITIGATION TECHNIQUES IN HOMES CONTAINING
INDOOR RADON CONCENTRATIONS EXCEEDING 4 pCi/L
House Selection
The first step was identifying homes in New York State containing indoor radon
concentrations of more than 4 pCi/L. To accomplish this, the Bureau of Environmental Radiation
Protection of the New York State Department of Health (NYSDOH) conducted a survey of homes
in areas likely to contain high radon levels. From this survey, Orange, Putnam, Albany and
Rensselaer counties were selected as the areas for inclusion in the portion of the study. Initial
screening tests were conducted between August and November 1986. Soil radium content
measurements, soil radon measurements, and water supply radon concentration measurements were
taken at the homes. The final house selection was completed during November 1986. Eight homes
in the Albany and Rensselaer county area, designated by the prefix AR, and eight homes in the
Orange and Putnam county area, designated by the prefix OP, were selected for inclusion in this
study.
Geology of Areas Selected
The geologies of the two areas in this study are vastly different. The Albany/Rensselaer
county area bedrock consists of graywacke, a conglomerate of sandstone and shale. The bedrock is
covered with a layer of gravelly glacial outwash 15 to 200-feet-deep. This layer of gravel is generally
well-drained and highly permeable.
The Orange/Putnam county area bedrock is dominated by a granitic gneiss of the Reading
Prong geological formation. Outcrops of unweathered gneiss and detached boulders are common
throughout this area. Several outcroppings of the Orange County bedrock show elevated gamma
levels. There were no reports of elevated gamma readings in the Putnam County area. Surficial soil
in both counties is very shallow. Typically, the surface layer is a 15 inch gravelly silt.
Task 1 Design
The overall objective of this task was the installation of mitigation systems in the homes in
order to determine the effect each system had on the indoor radon concentration. Each system is
referred to as a Phase. For example, Phase 1 may have been the installation of a sub-slab
depressurization system. Phase 2 may have involved sealing a French drain and de-activating the
S-2
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sub-slab depressurization system. Phase 3 may have required adding a wall depressurization system
to work in combination with the sealed French drain and the activated sub-slab depressurization
system. Using this approach, data could be gathered to demonstrate the effectiveness of a sub-slab
depressurization system, of sealing as a stand-alone mitigation technique, and of a sub-slab/wall
depressurization system with floor and wall penetrations sealed. It was clearly understood in most
of the homes that some of the phases installed were not expected to reduce the indoor radon
concentration below the 4 pCi/L guideline set for this project. A combination of all phases installed,
however, was expected to result in indoor concentrations of below 4 pCi/L.
Radon Sampling Methods
A variety of radon sampling methods was used throughout this project. The initial screening
tests conducted by the NYSDOH used short-term activated charcoal canisters (CC). Longer-term
monitoring at each house using alpha-track detectors (ATD) was performed before any mitigation
work was started, and after all mitigation work was completed. Radon grab samples (GR) were used
during diagnostic testing to help determine radon entry points and source strengths. Radon sniffing
techniques (RS) were developed in this and other research projects conducted at the time. Finally,
continuous radon monitors (CRM) were used to provide information on the immediate effectiveness
of an installed mitigation technique. Refer to Section 2 for a more complete discussion on the types
of testing used.
Diagnostic Testing
Diagnostic testing was performed at the Orange and Putnam county homes during November
1986, and at the Albany and Rensselaer county homes during February 1987. The purpose of the
diagnostic testing was to investigate building characteristics such as foundation integrity, and building
dynamics such as air pressure relationships, and to determine the effect these parameters had on the
indoor radon concentrations.
Field teams investigating each home performed a series of tests. Grab samples of the indoor
ambient air were taken at each house. These ambient air samples served two purposes: 1) to give
the diagnosticians an indication of their exposure to radon; and 2) to provide a reference point for
the comparison of subsequent grab samples from suspected radon entry points. The comparison of
the grab samples taken at suspected radon entry points to the ambient air grab samples classified the
relative concentration of the suspected radon entry point. In this project as a rule of thumb, any
S-3
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suspected radon entry point that exhibited radon concentrations three times higher than the ambient
sample was considered a source requiring treatment.
Communications testing, also called connectivity testing, was conducted to determine the
ability to move air under the floor slab, within hollow-core concrete block foundation walls, and
between the area beneath the floor slab and the hollow-core walls. Essentially, a vacuum (air
pressure negative relative to the basement air pressure) was developed beneath the floor slab or
within the hollow-core walls. Pressure differential instruments were then used to map the extent and
strength of the pressure field being developed. The data gathered during communication testing
helped the diagnostician choose the fan type and size to use in the active depressurization systems.
Visual inspections of the home were made to catalogue building characteristics that enhance
radon entry. Typical characteristics noted were the number and size of exhaust fans, number and type
of combustion appliances, and the integrity of the building's foundation.
All information obtained from the site, including the data gathered during the diagnostic
testing period, was used to determine which mitigation systems should be applied to the site. These
systems were applied in phases to determine the effectiveness of each system in reducing the radon
level. The final goal was to reach the EPA radon level guideline of 4 pCi/L when all phases were
complete and operating.
Mitigation Systems Demonstrated
Three elements must be present for a home to have an indoor radon problem: 1) a source
of radon; 2) a driving force that transports the radon from the source to the ambient air in the
house; 3) pathways for the radon to move from the source into the building if the source is outside
the building. The home will not have a radon problem if any one of these conditions does not exist.
Mitigation systems installed during this project included the sealing of soil gas entry points;
variations of sub-slab and soil depressurization; sub-membrane depressurization; wall
depressurization; basement pressurization; and, water treatment. Each of these mitigation
techniques attempts to remove at least one of the three prerequisites.
S-4
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Mitigation System Results
The reduction of the radon level within each house on a percentage reduction basis showed
the effectiveness of each mitigation technique. This was obtained by comparing the pre-mitigation
and post-mitigation time-weighted average radon concentrations. Time-weighted average radon
concentrations are hourly concentrations in the home quantified using a continuous radon monitor,
and averaged over the length of the monitoring period. It must be understood, however, that all
parameters affecting the final indoor radon concentration must be considered when comparing
pre-mitigation and post-mitigation radon concentrations. Any conclusion judging the effectiveness
of a system based solely upon the short-term (less than a week) radon concentrations is tenuous at
best. The relative short-term measurements should be considered as an indication of the effectiveness
of each system versus another system rather than an indication of the annual average radon
concentration.
Tables S-l to S-4 present the results of the mitigation systems installed. Trend plots
illustrating the continuous data used in calculating the time-weighted averages presented in these
tables can be found in Appendix A.
Sealing of Soil Gas Entry Points
One way to eliminate the pathway from the radon source to the inside of a house is by sealing
all of the cracks, holes, and other penetrations that pierce the foundation. Sealing soil gas entry
points as a stand-alone mitigation technique was tested in six homes. Typical penetration points
found in the project homes included French drains, utility and plumbing penetrations through side
walls in the basement, floor drains, and floor and wall cracks. These penetrations were sealed as part
of this task. Results of the sealing efforts are presented in Table S-l.
The percentage of radon reduction in these homes due to sealing of soil gas entry points
ranged from a low of 2% (AR-01) to a high of 74% (AR-20). This large difference in radon level
reductions can be attributed to several factors. The primary factor was the relative contribution of
the original penetration to the total indoor radon concentration. In other words, if the penetration,
such as a French drain, was responsible for permitting 70% of the total radon gases to enter the
house, then sealing this penetration produced a significant reduction in radon level. Similarly, sealing
a small wall crack that was a minor contributor to the total radon level, produced only a small
reduction. Another factor was the existence of inaccessible entry points that were not sealed in each
home. Finally, the indoor radon concentration may have been caused by sources which were not
S-5
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affected by sealing.
As shown in Table S-l, the sealing of penetrations usually reduces radon levels. However,
these results show that these reductions were not sufficient to bring the radon levels below the EPA
guideline of 4 pCi/L.
TABLE S-l
RESULTS OF SEALING FOUNDATION PENETRATIONS
HOUSE PRE-MITIGATION POST-MITIGATION
ID CONCENTRATION CONCENTRATION REDUCTION
(pCi/L) (pCi/L) (%)
AR-01 17.5 17.1 2
AR-09 22.5 9.9 56
AR-16 15.5 5.7 63
AR-17 23.6 9.1 61
AR-20 35.7 9.3 74
OP-09 23.5 14.7 37
Sub-slab Depressurization
The predominant transport mechanism that moves radon from its source to the openings in
the home's foundation is air movement by pressure differentials. Just as gravity forces water to flow
from a high area to a lower area, pressure differentials force gases to move from a high pressure area
to a low pressure area. Most buildings, for a variety of reasons, maintain an indoor air pressure that
is lower (negative) than the air pressure outside of the building or in the soil surrounding the home.
Depressurization systems attempt to reverse this by creating an area of pressure in the soil
surrounding the home that is lower than the indoor air pressure.
Sub-slab depressurization systems using regenerative and centrifugal blowers were
demonstrated in this project. Refer to Section 2 for a discussion on the factors involved in choosing
the blower types, and the homes in which they were used.
Sub-slab depressurization systems using regenerative blowers were tried in two homes.
Regenerative blowers were selected for use in these two homes because of the compactness of the
sub-slab aggregate. It was theorized that the regenerative blower, with its low airflow and high static
S-6
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pressure operating characteristics, would prove to be more effective than the centrifugal blower in
these homes. One home, OP-01, had no sealing of foundation penetrations performed during this
phase of the demonstration. Radon concentrations in this home were reduced to an average of 12.3
pCi/L from a pre-mitigation average of 20.6 pCi/L.
House OP-09 also had a regenerative blower depressurization system installed. Radon
concentrations averaged 11.4 pCi/L prior to the installation of the system, and were reduced to 3.4
pCi/L after system installation.
Sub-slab depressurization using a centrifugal blower with no sealing of foundation
penetrations was demonstrated in six homes. Reductions of 4% to 93% were achieved. As in the
case of nearly all mitigation system types demonstrated during this project, a wide range of reductions
was evident. The data gathered during this project were informative and valuable because of the
wide ranges of reductions for each system type and the reasons for these variations. In the case of
the house with the lowest reduction (AR-19), very large floor cracks adversely affected the operation
of the sub-slab depressurization system. Most of the other homes had minor floor cracks that did not
greatly interfere with the sub-slab depressurization system.
Two of the homes were scheduled to have sealing performed as the next phase, while the
other homes were scheduled to have sealing and some other mitigation technique installed, such as
the sub-slab depressurization system combined with sealing and wall depressurization. Sealing of
penetrations in House AR-17, in combination with the sub-slab depressurization system, resulted in
a further reduction of 2% (91% to 93%). This small decrease in radon concentrations should not
be considered as a cost-effective improvement in effectiveness because the radon concentrations for
both phases were below the 4 pCi/L guideline (2.2 pCi/1 versus 1.6 pCi/L). In fact, when considering
the lower level of detection of the radon monitoring equipment being used, and the natural variation
of radon concentrations, there really is no difference between the two phases. The results of the
sub-slab depressurization systems are summarized in Table S-2.
The results of the sub-slab depressurization systems show significant reductions in radon
levels. These reductions, however, did not necessarily bring the radon concentrations below the EPA
guideline. In some cases, penetration sealing or another radon mitigation technique was necessary
to meet this guideline.
S-7
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TABLE S-2
RESULTS OF SUB-SLAB DEPRESSURIZATION SYSTEMS
HOUSE
ID
AR-04 :>2
AR-05 l'2
AR-09 l>2
AR-17 l>2
AR-17 1'3
AR-19 1)2
OP-01 1>2
OP-01 2'4
OP-09 4'5
OP-13 u
PRE-MITIGATION
CONCENTRATION
(pCi/L)
22.8
21.3
22.5 6
23.6
23.6 6
12.3 6
20.6
20.6 6
11.4
13.9 6
POST-MITIGATION
CONCENTRATION
(pCi/L)
13.2
4.2
1.5
2.2
1.6
21.8 7
14.3
12.3
3.4
9.1
REDUCTION
42
80
93
91
93
N/A
31
41
70
35
Notes:
1. Sub-slab depressurization system with centrifugal blower.
2. No sealing of radon entry points performed.
3. Radon entry points sealed.
4. Sub-slab depressurization system with regenerative blower.
5. Basement walls sealed.
6. Period not immediately prior to post-mitigation monitoring period.
7. Pre-mitigation test period was from mid-February through early April 1987,
while the post-mitigation period was for the month of February 1988. Different
weather conditions and an ineffective sub-slab depressurization system installed
by the homeowner caused this system to increase its radon level during the post-
mitigation period (see Section 2.7 for details).
Footing Drain Depressurization
Three of the project homes had footing drains that were connected to a, depressurization
system. The drainage systems in Houses AR-16 and AR-20 were complete interior loop footing
drains that were terminated inside sump holes. The footing drain at House OP-13 was an exterior
footing drain that drained to an area above the ground. Radon reduction at these three homes
ranged from 79% to 95%. This consistently high reduction is due to the footing drain which helped
to extend the negative pressure field around the building perimeter. It should be noted that the
sub-slab aggregate at all three homes consisted of a natural gravelly soil and not the clean imported
S-8
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DOT #2 pebbles currently being prescribed for a sub-slab aggregate. Although a very small sample
population, the success of these three systems indicates that in areas where pebbles are not readily
accessible for new home construction, a pipe loop may prove to be a viable option. The results of
the footing drain depressurization systems are summarized in Table S-3.
TABLE S-3
RESULTS OF FOOTING DRAIN DEPRESSURIZATION SYSTEMS
HOUSE PRE-MITIGATION POST-MITIGATION
ID CONCENTRATION CONCENTRATION REDUCTION
(pCi/L) (pCi/L) (%)
AR-161'2 15.5 0.8 95
AR-20 1)2 35.7 2.3 94
OP-13 3'4 13.9 2.9 79
Notes:
1. Depressurization of interior footing drain connected to sump hole.
2. French drains and other floor penetrations not sealed during this phase.
3. Depressurization of exterior footing drain that drains to daylight.
4. Roor penetrations also sealed during this phase.
Wall Depressurization Systems
Outside wall depressurization was demonstrated in three homes. Reductions ranged from
28% (OP-16) to 98% (AR-01). In the case of the house with the lowest reduction (OP-16), 1-1/2"
passive vents were installed about every four feet around the perimeter of the building's foundation.
Floor penetrations and accessible hollow-core block tops were sealed during this phase and resulted
in a 28% reduction in radon levels. These passive vents were later plugged and an active system
installed. Reductions for the active system reached 59%. A final phase at this house involved
extensive and complicated sealing of all hollow-core block tops. This final sealing greatly improved
the efficiency of the wall depressurization system. Refer to Table S-4 for the results of wall
depressurization systems.
The other houses, where outside wall depressurization was demonstrated, involved fairly
straightforward installations and provided satisfactory results.
S-9
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TABLE S-4
RESULTS OF WALL DEPRESSURIZATION SYSTEMS
HOUSE PRE-MITIGATION POST-MITIGATION
ID CONCENTRATION CONCENTRATION REDUCTION
(pCi/L) (pCi/L) (%)
AR-01 17.5 0.4 98
OP-01 19.9 3.1 84
OP-16 l 55.4 40.1 28
OP-162 13.9 2.9 79
Notes:
1. Passive depressurization.
2. Active depressurization and sealing of tops of hollow-core concrete blocks.
Basement Pressurization
This technique was successfully demonstrated at one site. Radon concentrations were
maintained at a level of less than 4 pCi/L for almost a year. The system was unobtrusive and quiet.
A device was installed that turned the pressurization off in the event of a fire. Smoke alarms
equipped with normally closed relays were wired into the fan system. Therefore, if the smoke alarm
was activated, the relay would open, and the fan would turn off.
A difficulty with the basement pressurization system, although an effective radon mitigation
technique, was the ease with which it could be defeated. For example, if the basement door or
window was left open, the basement would not pressurize and consequently, radon concentrations
would increase. However, provisions to lessen this problem, such as making the basement windows
inoperable and providing automatic door closers, could be implemented.
Water Treatment
The water supply was a major source of indoor radon in two homes. Two types of water
treatment devices were demonstrated, an activated charcoal filter that adsorbs the radon, and a water
aeration system that aerates the water and causes the radon to outgas. Both systems performed well,
but because the water supply contained unusually high radon concentrations, the activated charcoal
filter quickly became a source of gamma radiation from the decay of the adsorbed radon. Since this
S-10
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was unacceptable, a water aeration unit was installed before the charcoal filter to remove radon from
the water. The charcoal filter was left in place to help improve the taste of the water for the
homeowner. The water aeration systems performed very well in reducing radon concentrations.
However, the systems installed during this project occupied a large area in the garage and crawl space
and were extremely noisy.
Overall Results
The overall systems and results from Task I, Subtask 1, which demonstrated radon mitigation
techniques in homes containing indoor radon concentrations of more than 4 pCi/L, varied from site
to site depending upon the location of the radon source. Sealing all accessible penetrations in the
basement was an effective way of reducing the radon concentration, even though this method did not
result in radon levels that would satisfy the EPA guideline. Results demonstrated, however, that
sealing foundation penetrations increases the effectiveness of the overall active depressurization
systems.
The decision to depressurize the footing drain, sub-slab, or basement wall depends on the
location of the radon source and the construction of the home. Grab samples or radon sniffing
techniques were used to identify these sources prior to the installation of the appropriate
depressurization system. In some cases, such as House OP-01, the home had two sources of radon
entry which required the depressurization of both locations. Radon mitigation contractors should be
aware of the possibility of multiple sources in existing homes and be prepared to address this problem.
All data presented to this point reflects the results of the mitigation efforts on a
system-by-system basis. The effectiveness of each system has been derived from short-term
pre-mitigation and post-mitigation monitoring. While this type of information is useful to illustrate
an immediate effect of any mitigation effort, the final conclusions as to the effectiveness of any
complete mitigation system should be based on long-term measurements.
S-ll
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TASK I, SUBTASK 2
ASSESS EFFECTIVENESS AND DURABILITY OF PREVIOUSLY INSTALLED
RADON MITIGATION TECHNIQUES
Fourteen homes were found to contain elevated levels of radon in a pioneering indoor air
quality and ventilation study sponsored by NYSERDA and Niagara Mohawk Power Corporation.
Low-cost mitigation systems were installed in these homes in 1984. These homes were revisited
during this project to assess the long-term effectiveness of the original systems.
During the original study, numerous mitigation systems were installed in the homes. These
systems included sub-slab depressurization systems, sealing of radon entry points, and increased
ventilation through the use of heat recovery ventilators.
Each of the 14 homes was visited in 1986 and 1987, during which a thorough inspection was
made to determine the condition and effectiveness of the original mitigation system. In most homes,
detailed diagnostic testing included visual inspections and pressure differential measurements.
Short-term radon measurements using charcoal canisters were also made. If parts of the systems were
working improperly, those components were replaced, updated, or redesigned. Short-term
measurements using charcoal canisters were then repeated, followed by long-term measurements using
alpha-track detectors.
Of the 11 homes in the original study that contained radon concentrations of more than 4
pCi/L, (three were below 4 pCi/L in the original study, but were mitigated nevertheless), seven were
brought below 4 pCi/L by the original systems. It was found during the reinvestigation that six of
the original 11 homes contained short-term levels above 4 pCi/L. With the original systems modified,
nine homes contained average long-term concentrations below 4 pCi/L.
Problems found in the original systems included weak pressure fields being developed by the
sub-slab depressurization systems. This was caused primarily by the use of axial computer-type fans
in the original study. These fans were replaced with more appropriate in-line centrifugal fans that
are now in widespread use.
The design of some of the sub-slab systems was also a problem in some homes. Low points
in the exhaust piping allowed water to collect and block the airflow. Exhausts near ground level
allowed foreign objects to be placed in the ends of the pipes, blocking airflow.
The condition of the sealants used in the original study was varied. Generally, polyurethane
caulk was found to be in good condition. Butyl caulk, on the other hand, had deteriorated.
S-12
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The heat recovery ventilators had little or no impact on the indoor radon concentrations.
This is due to the low air exchange rates produced by the particular heat recovery ventilator. All
ventilators, however, were operating satisfactorily.
Refer to Section 3 for a house-by-house discussion on the activity and results observed during
this subtask.
TASK II
DEMONSTRATE RADON-RESISTANT TECHNIQUES IN NEW HOUSE CONSTRUCTION
In this task, radon-resistant construction techniques were applied to 15 new houses. Emphasis
was placed on the development of cost-effective passive methods of radon-resistant construction with
potential applicability to building codes.
Housing site selection was critical to the success of this task because of the need to presume
high radon levels in houses not yet built. A study of 210 homes by the Onondaga County Health
Department identified a band of bedrock with high radon levels running through parts of the county.
Based on this information, several sub-divisions were identified as possible participants in this task.
The four mitigation methods installed in the houses during construction were:
* Sealing foundation floors
* Sealing concrete block foundation walls
* Passive sub-slab depressurization
* Active sub-slab depressurization
Sealing Foundation Floors
The foundation floor was sealed on all test houses except ON-18 by installing a continuous
airtight plastic film over the sub-slab aggregate prior to the pouring of the slab. Joints, tears,
punctures, or other penetrations were sealed with builder's tape. The interior and/or exterior footing
drains were discharged to an area above the ground whenever possible to avoid the introduction of
an interior sump. If the footing drains discharged into an interior sump, the sump was fitted with an
airtight cover. The water content of the concrete mix was kept as low as possible to reduce shrinkage
and cracks. Houses ON-06, ON-09, and ON-10 were extensively inspected before, during, and after
the slab was poured to ensure adherence to the guidelines set by the designer. Less extensive
S-13
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extensive spot-checking was done on the remainder of the houses.
Sealing Concrete Block Foundation Walls
All homes in this task had concrete block walls. An obvious problem with concrete block
walls is the necessity to build sub-foundations below the normal level of the footing. The
sub-foundation normally consists of a footing poured on solid undisturbed soil on which the concrete
block wall is built up to the level of the normal footing. Since the primary concern in coating the
outside walls is to prevent water migration through the walls into the basement, sub-foundation walls
are not normally coated below the slab level. However, this allows radon to migrate through the
uncoated concrete blocks below the slab into the block cavity, and up through the blocks into the
basement. In order to avoid this problem, the builder was instructed to install a course of solid
concrete blocks level with the aggregate.
The exterior of the foundation walls from the top of the foundation wall to the footing level
was pargeted with either a Portland cement with bituminous coating or a surface-bonding cement.
Passive Sub-slab Depressurization
All of the homes in this study had interior and/or exterior footing drains surrounded by a layer
of crushed stone. Passive sub-slab ventilation would be expected to be most effective if the sub-slab
aggregate and sub-slab drainage pipes were vented from a central location with a large diameter vent
pipe directly to the peak of the roof; however, to keep installation costs to a minimum, all (except
one) of the passive sub-slab ventilation systems consisted of four-inch PVC pipes connected to the
footing drains, which were then routed to the outside at the rim joist in one, two, or three locations
on each side of the test site. The side of the house that received the prevailing wind did not include
a passive vent.
Active Sub-slab Depressurization
The primary emphases of Task II were the development of effective radon barrier techniques
and the testing of passive methods of providing sub-slab ventilation. However, if the passive
mitigation system was not effective in reducing the radon level below the EPA guideline, a centrifugal
fan was connected to the sub-slab ventilation system to form an active depressurization system. In
S-14
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homes where there were two or more passive sub-slab vents, all but one of the vents were capped
and a centrifugal fan was connected to the remaining vent. The fan was placed in the basement as
close to the rim joist as possible due to strong objections of homeowners who did not want a fan
visible on the home's exterior. The obvious disadvantage to that configuration is the possibility of
leaks in the fan and piping allowing radon to be blown into the home.
Results and Conclusions
Radon-resistant construction techniques demonstrated during this task proved to be successful
at lowering the overall radon level in the houses studied. Additionally, the cost of incorporating these
techniques into construction was shown to be three times lower than the cost of retrofitting mitigation
techniques.
Sealing and passive ventilation techniques incorporated into newly constructed houses were
successful at reducing ambient radon concentrations in three of the 15 houses. In the remaining 12
sites, however, the installation of active sub-slab depressurization systems was required to bring the
radon levels successfully below the EPA guideline. (Despite an active system, one site, House ON-18,
did not meet the EPA guideline because of incorrect application of the mitigation techniques by the
builder.) Table S-5 presents the results from the 15 test sites.
Because multiple passive sub-slab depressurization systems generally do not reduce radon
levels below the EPA guideline, it is suggested that only one passive vent be installed during
construction. This will minimize the cost of the passive ventilation system and still permit the
addition of a centrifugal fan to create an active depressurization system. As previously stated, this
radon-resistant technique was effective at reducing radon levels below the EPA guideline when a site
was fitted with a correctly-installed active depressurization system.
The five control sites, located in the same developments as the 15 test sites, but without radon
mitigation systems, had an average pre-mitigation radon level of 22 pCi/L (refer to Table S-6). The
control sites were used to insure that the new homes built in the developments with radon-resistant
techniques were lower in radon concentration because of these construction techniques and not
because of low radon levels in the immediate area. All of these sites were successfully mitigated using
sub-slab depressurization systems. However, the cost for retrofitting these sites was three times
higher than the total cost of the system at the houses where the radon-resistant techniques were
integrated during construction.
Refer to Section 4 for a house-by-house discussion of the results of this task.
S-15
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TABLE S-5
RESULTS FROM NEW CONSTRUCTION TEST SITES
HOUSE
ID
ON-061'2
ON-072
ON-081'2
ON-09
ON-10
ON-11
ON-12
ON-13
ON-144
ON-15
ON-16
ON-17
ON-186
ON-19
ON-20
Notes:
1.
2.
3.
4.
5.
6.
AS-BUILT
CONCENTRATION
(pCi/L)
3 5
4-7
5
29
6-8
8
4
13- 18
N/A
7
25
8
25-58
12 16
25
PASSIVE
VENTILATION
CONCENTRATION
(pCi/L)
3-5
N/A
5
19 20
6-8
7-8
4
10
N/A
6-7
14
7
28
10
21-23
ACTIVE
DEPRESSURIZATION
CONCENTRATION
(pCi/L)
N/A
N/A
N/A
1
<1
2
2
2
2
1-2
2
1 2
8
3-4
2-3
Vented drains discharged to daylight.
Homeowner decided not to install active depressurization system.
N/A = not available; phase was not investigated.
Results from as-built and with passive ventilation are not available.
All results are from various measurement devices including AT, CC, and CR.
Radon-resistant techniques installed incorrectly including a severed sub-slab drain.
HOUSE
ID
ON-01
ON-02
ON-03
ON-04
ON-05
TABLE S-6
RESULTS FROM NEW CONSTRUCTION CONTROL SITES
AS-BUILT
CONCENTRATION
(pCi/L)
33
7
27
25
19
ACTIVE
DEPRESSURIZATION
CONCENTRATION
(pCi/L)
3
3
2
3
3
Notes: All results are from various measurement devices including AT, CC and CR.
S-16
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SECTION 1
INTRODUCTION
The scope of any research effort is defined by its goals and objectives. In the field of
naturally occurring radon, emphasis may be placed on any of many factors, including: mapping the
extend of the problem; discovering effects of radon on health; developing greater understanding of
radon dynamics; streamlining the diagnostic process; comparing the costs and effectiveness of different
mitigation strategies; demonstrating the most cost-effective techniques; and, expanding private sector
involvement through technology transfer. The allocation of resources within each project is the result
of the prioritization of objectives.
The overall goals of this project are outlined in Table 1-1. Specific objectives are presented
in Table 1-2. These goals and objectives were being carried out in three broad task areas outlined
in Table 1-3. Tables 1-1 and 1-2 relate the goals and objectives to the specific tasks and subtasks in
parenthesis. More specific goals of tasks I and n are displayed in Tables 1-4 and 1-5, respectively.
The following sections provide a report on the three broad task areas of this project: Section
2 (Demonstrating Radon Reduction Techniques in Existing Houses) reports on Task I, Subtask 1;
Section 3 (Assessing Previously Installed Mitigation Techniques in Existing Houses) reports on Task
I, Subtask 2; and Section 4 (Demonstrating Radon-Resistant New Construction Techniques) reports
on Task II.
1-1
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TABLE 1-1. OVERALL PROJECT GOALS
DEMONSTRATE COST-EFFECTIVE MITIGATIVE TECHNIQUES THAT
CAN BE APPLIED TO EXISTING HOUSES THAT CONTAIN UNACCEPT-
ABLE INDOOR LEVELS OR RADON (TASK I).
DEMONSTRATE RADON-RESISTANT CONSTRUCTION TECHNIQUES
TO GUIDE HOUSE CONSTRUCTION IN AREAS WITH HIGH RADON
RISK. PROVIDE INFORMATION TO AID IN THE DEVELOPMENT OF
NEW HOUSE CONSTRUCTION CODES THAT ADDRESS POTENTIAL
RADON PROBLEMS (TASK II).
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TABLE 1-2. SPECIFIC OBJECTIVES
1. DEMONSTRATE COST-EFFECTIVE* ENGINEERING SOLUTIONS THAT CAN
BE USED TO MITIGATE UNACCEPTABLE CONCENCENTRATION OF RADON
INSIDE HOUSES (TASK I SUBTASK 1).
2. ASSESS THE EFFECTIVENESS OF CERTAIN ENGINEERING SOLUTIONS THAT
WERE IMPLEMENTED IN 14 HOUSES IN NIAGARA MOHAWK POWER COR-
PORATION'S SERVICE TERRITORY TO MITIGATE HIGH INDOOR LEVELS OF
RADON (TASK I SUBTASK 2).
3. DEMONSTRATE COST-EFFECTIVE* ENGINEERING SOLUTIONS THAT CAN
BE APPLIED TO NEW HOUSES WHERE THE POTENTIAL LEVELS OF INDOOR
RADON WOULD OTHERWISE BE UNACCEPTABLE (TASK II).
4. ANALYZE AND DOCUMENT THE DYNAMIC CHANGES IN HOUSES ASSOCI-
ATED WITH THE ABOVE MITIGATIVE TECHNIQUES WITH REGARD TO
REDUCING INDOOR RADON CONCENTRATIONS INCLUDING VARIATIONS
DUE TO OUTDOOR TEMPERATURE FLUCTUATIONS AND THE MOVEMENT
OF RADON TO OTHER LEVELS IN THE TEST SITES (TASKS I AND II).
5. ASSESS THE COST OF IMPLEMENTATION AND OPERATION OF THE ABOVE
MITIGATIVE TECHNIQUES FOR TYPICAL HOUSES (TASKS I AND II).
* ACHIEVEMENT OF DESIRED INDOOR RADON LEVEL AT LEAST COST WITH
CONSIDERATION OF MAINTAINING COMFORT.
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TABLE 1-3. LIST OF TASKS AND SUBTASKS
TASK I: DEMONSTRATE RADON-MITIGATION TECHNIQUES IN EXISTING
HOUSES
SUBTASK 1: DEMONSTRATE COST-EFFECTIVE TECHNIQUES IN 16 HOUSES
SUBTASK 2: ASSESS PREVIOUSLY-INSTALLED TECHNIQUES IN 14 HOUSES
TASK II: DEMONSTATE RADON-RESISTANT CONSTRUCTION TECHNIQUES IN
15 NEW HOUSES
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TABLE 1-4. GOALS OF TASK I
DEMONSTRATE TECHNIQUES IN EXISTING HOUSES
REDUCE INDOOR RADON CONCENTRATIONS TO LEVELS THAT ARE
CONSISTENT WITH EPA GUIDELINES.
ASSURE THAT THE INDOOR RADON LEVELS ACHIEVED ARE UNDER-
STOOD BY THE HOMEOWNER.
DEVELOP APPROACHES THAT ARE COST-EFFECTIVE OVER THE LONG
TERM (15-20 YEARS).
DEVELOP TECHNIQUES THAT ARE PERMANENT AND UNLIKELY TO
DETERIORATE WITH TIME (NORMAL WEAR AND TEAR EXPECTED), OR
THAT CAN BE EASILY AND COST-EFFECTIVELY REPAIRED.
IDENTIFY APPROACHES THAT ARE HIGHLY LIKELY TO REDUCE RADON
TO TARGET LEVEL OR AT LEAST RESULT IN MAJOR REDUCTIONS IF THE
TARGET LEVEL CANNOT BE MET.
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TABLE 1-5. GOALS OF TASK II
DEMONSTRATE TECHNIQUES IN NEW HOUSES
RADON-RESISTANT CONSTRUCTION PLAN REQUIREMENTS
DEVELOP METHODS WHICH ARE COST-EFFECTIVE OVER THE LONG TERM
(AS DEFINED UNDER TASK I).
MEET APLICABLE GOALS OF TASK I.
SELECT METHODS WHICH ARE ACCEPTABLE TO AND UNDERSTOOD BY
PROJECT MANAGERS, PROSPECTIVE BUYERS, HOUSE BUILDERS AND
MITIGATION CONTRACTOR.
IDENTIFY METHODS WHICH ARE READILY IMPLEMENTED.
FURNISH PROVISIONS FOR PROTECTION OF WORKERS FROM HIGH RADON
EXPOSURE, IF NECESSARY.
INCLUDE DESCRIPTION OF APPROPRIATE SHORT-TERM AND LONG-TERM
MONITORING.
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SECTION 2
DEMONSTRATING RADON REDUCTION TECHNIQUES IN EXISTING HOMES
2.0 OVERVIEW
House Selection
The objective of this portion of the study was to demonstrate the effectiveness of certain
radon reduction methods in New York State homes. To accomplish this task, 16 single-family
detached houses, eight in the Albany/Rensselaer county area, designated with the prefix AR, and
eight in the Orange/Putnam county area, designated OP, were selected. The homes in this study
represented an assortment of construction types including raised ranch, split-level, bi-level ranches,
and Cape Cod style homes. Most of the homes were of wood-frame construction, although one home
had full height masonry walls. Substructure types included finished and unfinished basements, crawl
spaces, combination basement and crawl space, and combination basement and slab-on-grade
foundations. Foundations consisted of hollow-core masonry units and poured concrete walls. A
house-by-house description of construction characteristics is presented in this section.
Initial radon screening measurements in the study homes ranged from 20 to 180 pCi/L. These
initial screening measurements were taken using short-term activated charcoal methods during
August, September, October, and November 1986. Soil radon and radium content, and soil
permeability and domestic water supply radon content were measured at each home. The results of
the initial screening tests are presented in Table 2-1.
Field teams visited each home to perform a series of diagnostic procedures including radon
source identification, communications testing, and house construction and occupant behavior surveys.
The diagnostic data were used to help determine the appropriate mitigation strategies for each house.
The tests performed and the data collected during the diagnostic testing are presented in this section.
Mitigation strategies demonstrated throughout the course of this project included sub-slab and
sub-membrane depressurization, exterior and interior footing drain depressurization, basement
pressurization, water treatment, and sealing methods. A detailed description of the mitigation
methods used and the results of each method are described in this section. A house-by-house
description of each system is also presented in this section.
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TABLE 2-1
RESULTS OF INITIAL SURVEY
PERFORMED BY THE BUREAU OF ENVIRONMENTAL RADIATION PROTECTION,
NEW YORK STATE DEPARTMENT OF HEALTH
HOUSE
ID
AR-01
AR-04
AR-05
AR-09
AR-16
AR-17
AR-19
OP-01
OP-03
OP-05
OP-06
OP-09
OP-13
OP-16
OP-17
INDOOR
RADON
(pCi/L)
20
24
32
21
33
52
35
30
52
180
26
21
25
33
49
WATER
RADON
(pCi/L)
N/A
N/A
N/A
N/A
880
737
501
120
380,000
245,000
5,284
450
6,500
35,000
22,500
SOIL
Ra226
(pci/g)
1.10
1.05
1.24
1.23
0.93
1.10
0.90
1.00
3.90
2.50
1.50
1.24
3.50
6.00
3.00
SOIL
Rn222
(pCi/L)
420
275
290
1,000
390
120
670
800
14,000
3,500
600
350
7,700
1,100
60,000
SOIL
PERMEABILITY
(x 10'6 cm2)
8.00
4.00
6.00
6.30
0.65
1.00
2.00
2.00
4.50
0.30
0.40
3.50
3.10
8.20
0.45
Note:
1. These homes have public water supplies and were not tested for radon content.
Geology of Study Areas
The bedrock geology of the Albany county area is dominated by the Schenectady formation
which consists of graywacke, sandstone, silkstone, and shale. The bedrock formation does not outcrop
in the area of the homes in this study and is covered with 15 to 200 feet of glacial outwash gravel and
sand. The soil is well-drained and very permeable to gas flow.
The geology of the Rensselaer county area consists of a bedrock of graywacke and shale
covered with various depths of gravelly soil.
The Orange county area homes included in this project are built on a flat plateau
approximately 100 feet above the Hudson River. The bedrock geology of the area is dominated by
a granitic gneiss which is in the Reading Prong geologic formation. The gneiss contains biotite,
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quartz, and feldspar. Minor faulting is present in the bedrock due to tectonic events. Outcroppings
of unweathered gneiss and detached boulders are common throughout the area. Several of the
homes in this project are built directly on the bedrock, and study homes OP-05 and OP-06 have
exposed bedrock Outcroppings inside the crawl space and basement respectively.
Surveys using micro-R gamma meters indicated elevated gamma readings on many of the
exposed bedrock Outcroppings. For example, the exposed bedrock in the crawl space of house OP-05
produced gamma readings in the range of 40 to 300 mR/hr.
The Orange county area contains very shallow soils. During the last glaciation, ice moved
through the Hudson Valley from the north, leaving the hard gneiss bedrock exposed and only a thin
veneer of unconsolidated material as a surficial soil. Typically, the surface layer is a dark brown
gravelly silt five inches thick. The subsoil is a brown gravelly silt 10 inches thick. A hard granitic
bedrock can be found at a depth of 15 inches. The soil is low in organic matter and contains two to
25 percent gravel fragments. The surface layers contain silt, fine and course sand, and gravel. In
most areas the soil is highly permeable.
The bedrock geology of the Putnam county area is much the same as the Orange county area;
however, no reports of high gamma readings were found.
The surficial soil in the Putnam county area ranges from a fine grain till to a gravelly till.
Sampling Location
In order to produce standardized measurements, sample location selection criteria were
developed for this project. During the initial visit, a location on each level of the home was selected.
Typically, the basement measurement location is referred to as Location 1, and the first floor location
as Location 2. All subsequent measurements would be taken at these locations. All locations and
the measurements taken at these locations were made in accordance with EPA radon measurement
protocols.
Radon Measurement Methods
A variety of devices and methods are available to measure radon gas concentrations. The
method and instrument used depends on the need or application. A description of each type of
instrument and method used in this project follows.
Granulated Activated Charcoal Samplers
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Granulated activated charcoal samplers (CC) are devices that are used to take short-term (2-
to 7-day) radon measurements. The charcoal samplers used in this project consisted of open-topped
metal cans filled with granulated activated charcoal. A filter placed on the top of each can serves
to keep the charcoal in and also filters out radon decay products. The samplers are kept covered
with an airtight metal top until they are used. Once the metal top is removed, the measurement
period begins. Radon in the air diffuses through the filter and is adsorbed onto the charcoal. At the
end of the measurement period, the top is replaced and the sample sent to the laboratory for analysis.
The short duration of this sampling method provides a quick indication of the radon
concentration in the air. However, radon concentrations vary greatly with time, therefore,
measurements of this type should not be considered an accurate representation of the annual average
radon concentration.
When initially testing a home, the short duration of this sampling method has an advantage.
In a home with very high radon concentrations, it would not be beneficial to the homeowners to
conduct a test that requires several months to a year to complete. For example, consider the home
that contains several hundred pCi/L of radon. A short-term test would likely indicate radon
concentrations greater than 4 pCi/L, and alert the homeowners to a possible problem. One
disadvantage to this method is that in homes with slightly elevated concentrations, a test could easily
be conducted when the concentrations are temporarily low and provide the homeowners with a false
sense of security.
Alpha-Track Detector Samplers
An alpha-track detector (ATD) consists of a small piece of plastic enclosed in a container
with a filter-covered opening. Radon gas diffuses through the filter. When the radon inside the
detector decays, alpha particles emitted by the decay products strike the plastic and produce tracks
on the plastic that can be counted. Alpha-track detectors are normally deployed in a home for
periods of 1 month to 1 year.
An advantage of the ATD is the ability to leave the ATD in place for a full year. This will
give the annual average radon concentration. A disadvantage is that if the radon concentration in
the home is high, the occupants will be exposed to those levels during the testing period.
Normal testing procedures will use an activated charcoal sampler to give a quick indication
of the radon concentrations present in the air at the time of the test. The results of these tests can
then be evaluated, and the decision to install mitigation techniques or obtain the annual average
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through the use of ATDs can be made.
Continuous Radon Monitoring
The continuous radon monitors (CRM) used in this project sample the ambient air by passing
air through a filter and into a scintillation cell. A scintillation cell is a flask whose interior is coated
with a zinc sulfide phosphor. The filter over the scintillation cell removes dust and radon decay
products. As the radon in the air inside the cell decays, the ionized radon decay products plate out
on the interior of the cell. The decay products produce alpha emissions, and the alpha particles strike
the coating of zinc sulfide phosphor inside the cell, causing scintillations (light pulses) to occur. The
scintillations are detected by a light-sensitive photomultiplier tube (PMT), which then generates an
electrical signal. The signals are processed by the counting circuitry in the monitor and are stored
as counts. The counts can then be converted to a radon concentration in pCi/L. Continuous radon
monitors, if calibrated correctly, can provide a very accurate measure of the amount of radon in the
air.
With the type of CRM used in this project, hourly radon concentrations were recorded and
stored for later retrieval. Due to the ability of obtaining hourly radon concentrations, the CRM
provided very useful information regarding the cause and effect of the mitigation techniques installed
in the homes. A disadvantage of CRMs is the cost associated with purchasing and calibrating the
monitor.
Radon Grab Samples
Radon grab samples (GR) are short-term measurements (normally just a few minutes) that
provide an accurate representation of the radon concentration that is present in the air during the
time the sample is taken. Because of the short duration of the sampling, grab samples are not
accurate representations of long-term radon concentrations.
A grab sample is collected by drawing a sample of air through a filter which removes radon
decay products and deposits them into a scintillation cell. One surface of the cell is fitted with a clear
window that is put into contact with a photomultiplier tube. The PMT counts the scintillations
resulting from the alpha disintegrations interacting with the zinc sulfide coating. These scintillations
can be converted to a measurement of radon gas in pCi/L.
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Diagnostic Testing
Diagnostic testing was performed in each home to gather information that would help
determine the reason the house contained elevated radon concentrations and prescribe an effective
mitigation system. Due to the rapid growth in knowledge of radon entry and behavior that was taking
place at the time the project was conducted, techniques and equipment utilized were constantly
changing. An example is illustrated by the development of communications testing procedures. Prior
to the start of this project, diagnostic procedures for checking the movement of air from the sub-slab
area to the indoor area consisted of blowing a puff of smoke into a floor crack to see if it would
come back out. While this is useful, it is a qualitative and not quantitative measurement. During this
project, it became standard procedure to use a vacuum cleaner and magnehelic to provide a
quantitative measurement of airflow. Near the end of this project, efforts to use variable speed
vacuum cleaners that could be adjusted to more closely simulate a desired blower type were under
way. This rapid growth in equipment and techniques is reflected in many of the efforts undertaken
in this project.
To help disclose radon entry points in the homes, radon diagnostic measurements were taken.
The standard procedure for making diagnostic radon measurements throughout most of this project
was through the use of radon grab samples. Samples were usually taken from beneath the floor slab,
from within the cores of masonry foundation walls, and from a variety of other places to identify the
radon sources and areas of radon entry.
Other diagnostic measurements made included communications testing, which is performed
to determine the ability to move air or develop a pressure differential between two points. In this
project, testing was performed to determine the communications between points beneath the floor
slab, between a point beneath the floor slab and a point in the foundation wall, and between two
points within the foundation walls. These different tests are referred to as sub-slab, slab-to-wall, and
wall-to-wall communications.
During this project, a 1-1/4-inch diameter hole, and several remote 3/8-inch diameter holes
were drilled through the floor slab and foundation walls. A vacuum cleaner was then connected to
the large hole. The vacuum cleaner was turned on and airflow or pressure differentials checked at
the remote holes. Smokesticks were used to visually check for a reversal of airflow. Manometers
and magnehelics were used to check the pressure differentials. The results of this test provide an
indication of sub-slab and floor-to-wall communications. To determine the wall-to-wall
communications, a 1-1/4-inch diameter hole was drilled in a foundation wall. A vacuum was
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connected to the hole and turned on. Communication was checked with smoke sticks or instruments
at remote holes in the walls or at wall penetrations.
A grab sample taken in the exhaust stream of a vacuum during one test disclosed a radon
concentration in excess of 600 pCi/L. One of the first things learned on this project was to duct the
vacuum cleaner exhaust outside. This is now a standard procedure.
During the diagnostics visit, visual inspections of the homes were made. Building
characteristics that could increase the indoor/outdoor pressure differentials such as thermal by-passes
and exhaust fans were noted. Construction methods that would inhibit or aid the installation of
anticipated mitigation efforts were recorded.
All of the data collected during the diagnostic testing were used to select and design the
mitigation systems that were to be installed at each home.
Mitigation Systems Demonstrated
A variety of mitigation systems and radon reduction techniques were demonstrated in this
project, either singularly or in conjunction with other systems or techniques. Each system type and
reduction technique used in this project is discussed in this section.
Sub-slab depressurization systems are the most common radon mitigation systems installed in
the United States. A sub-slab depressurization system operates under the theory of altered
indoor/outdoor pressure differentials. If the area surrounding the building foundation can be kept
at a pressure that is lower than the pressure inside the building, then air will flow from the building
into the soil, rather than from the soil into the building.
One of the limiting factors in the use and effectiveness of a sub-slab depressurization system
is the permeability of the soil beneath the floor slab. If the soil is very compact and resistant to
airflow, then the ability to develop an extensive negative pressure field would be impaired. If the soil
is loose and permeable and allows air movement, then an extensive pressure field can easily be
developed and the sub-slab depressurization system would be effective.
Centrifugal blowers are commonly used in sub-slab depressurization systems. These type fans
typically have the ability to move 100 - 150 cfm of air at 0" H2O static pressure and 20 cfm at 1.5"
H2O static pressure. Many homes have a permeable sub-slab aggregate that allows the use of a
centrifugal blower of the type described above. A sub-slab aggregate of low permeability beneath the
home will preclude the use of a centrifugal blower. To determine if a fan with a vastly different
operating characteristic than a centrifugal blower could be utilized in a home with low permeability
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sub-slab aggregate, two homes were tested using a regenerative blower, rather than a centritugal
blower. Regenerative blowers have the ability to move a small volume of air at very high static
pressures. The type used in this project operated on the order of 26 cfm at 10" H2O static pressure.
In homes with combination basement/slab-on-grade substructures, the floor of the
slab-on-grade section will cap the soil. This cap will tend to force any radon that is beneath the slab
into the basement wall, from which it can enter the basement area. Several homes with combination
basement/slab-on-grade substructures had a sub-slab/wall depressurization system installed. This type
of system operates and is configured similarly to a sub-slab depressurization system except that the
interior of the hollow-core block wall that is common to the basement and slab-on-grade section, and
the sub-slab area, are depressurized. In the systems installed during this project, a single centrifugal
blower was used to provide active depressurization of both the walls and sub-slab area. Dampers
were placed in the pipe system to allow adjustment of airflows and system balancing.
Wall depressurization systems were also demonstrated. In these type systems, only the
foundation walls are depressurized.
In order for radon to enter a home, there must be openings in the foundation that will allow
the radon-laden soil gases to enter. Sealing of these entry points theoretically should reduce indoor
radon concentrations. In many of the homes, the mitigation techniques included the sealing of
suspected radon entry points. Typical entry points found in the study homes included below-grade
wall penetrations where water, waste, and utility lines entered, and floor and wall cracks formed by
the shrinkage of the concrete. Several of the homes had sanitary clean-out pits in the substructure.
Waste pipes are run through the pits to the outside and connected to the sewage disposal system.
The pits in the study homes were found to contain high concentrations of radon. Removable airtight
covers were constructed to seal the pits and stop radon from entering the basement. Other radon
entry points were sealed using various materials such as non-shrink grouts, closed-cell foams, and
polyurethane caulks.
In some homes conditions such as poor sub-slab communications, large unscalable
penetrations, and other factors preclude the use of depressurization systems or sealing to reduce
radon concentrations. In order to determine if a basement could be maintained at an air pressure
that is positive relative to the air pressure in the soil surrounding the building, and thus slow or stop
radon entry, basement pressurization systems were installed in two homes in this study. The systems
installed used a fan to exhaust upper-level conditioned air into the basement and create a high
pressure zone. They were also equipped with a smoke alarm and cut-off relay that would turn the
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fan off in the event of fire.
Two homes with elevated radon concentrations in the water supply were found during this
study. Water treatment methods included using charcoal filters or water aeration to remove
water-borne radon.
A house-by-house description of the work performed at each house follows.
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2.1 HOUSE AR-01
House Description
This home, a bi-level raised ranch, was built on a level lot in a subdivision in 1986. The
foundation consists of half-height capped hollow-core concrete block walls with a poured concrete
floor slab. A large portion of the walls are finished. The slab averages approximately two feet below-
grade. The slab is completely covered with vinyl tile and carpeting with the exception of a small bare
area beneath the stairs. A sanitary clean-out pit is beneath the stairway. A simplified floor plan for
this house can be found in Appendix A, Initial screening tests performed during October 1986
revealed a basement radon concentration of 19.5 pCi/L.
Diagnostic Testing Results/Interpretation
Diagnostic testing was performed during February 1987. Radon grab samples were used to
determine the sources of radon at this site. Two sources were discovered, a sanitary clean-out pit
with radon concentrations of 197 pCi/L, and the foundation walls where the average of several grab
samples was 298 pCi/L. A grab sample taken from beneath the floor slab disclosed a radon
concentration of 41 pCi/L.
Communications testing indicated that the soil beneath the slab was very resistant to airflow.
At a distance of three feet from the suction point, no airflow was noted by either the magnehelic nor
the smoke stick. Communications within the back wall were considered to be good. Air movement
at an approximate distance of 10 feet between the suction point and the test hole was noted,
however, the back wall and either side wall did not communicate through the ventilation system.
Based upon the diagnostic test results, initial mitigation plans prescribed a two-phase approach
at this home. Phase 1 involved the sealing of the sanitary cleanout pit. The pit would be fitted with
a removable, airtight cover. Phase 2 provided for the installation of a block-wall depressurization
system. The system would have to be designed to provide evacuation of the interior of the back wall
and the two side walls.
Pre-Mitigation Testing
Prior to performing any mitigation work, several radon measurements were made. The initial
screen testing performed during the last days of October 1986 disclosed short-term concentrations
of 19.5 pCi/L in the basement family room. A confirmatory short-term measurement made in the
same location a little over one month later disclosed a concentration of 20.0 pCi/L, and a
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measurement made on the first floor during this same time period disclosed a concentration of 15.9
pCi/L. An alpha-track detector placed in Location 2 (as seen in the floor plan found in Appendix
A), on the first floor, disclosed an average radon concentration of 11.9 from late February 1987 to
early April 1987. On April 2, 1987, a continuous monitor was placed in the basement family room
to provide the average radon concentration immediately prior to the start of mitigation efforts. The
average concentration for this time period was found to be 17.5 pCi/L. This value was used for the
pre-mitigation radon concentration.
Mitigation System Installation
Phase 1 was installed the first week of April 1987. A wooden frame constructed of 2" x 4"
studding was installed around the perimeter of the pit. A cover constructed of 3/4" exterior plywood
was then fitted on the framing. All seams and joints were caulked to provide a good seal, and the
installation was tested for airtightness using smoke sticks.
Phase 2 was installed during the later part of September 1987. Due to local codes, the
construction techniques used to build the home, and homeowner preferences, the following had to
be considered for design of the Phase 2 system:
1. No part of the installation, with the exception of the exhaust, could be visible from
the outside.
2. An exterior door in the back wall effectively made it two walls. The lack of back wall
to side wall communications required that all walls be manifolded together with PVC
piping.
With these requirements in mind, the final design of the system required that a shallow trench be dug
outside the home and run parallel to the back wall. The trench extended around the corner of the
back wall to allow access to the two side walls. PVC piping was placed in the trench and connected
to the three wall penetration points. A centrifugal fan was placed in the garage and connected to
the outside PVC manifold. The exhaust was led out through the garage wall and fun up to the eaves
of the house.
Short-Term Results
Pre-mitigation radon concentrations, disclosed by a continuous radon monitor placed in the
basement family room, averaged 17.5 pCi/L for a period of approximately seven days immediately
prior to the sealing of the sanitary pit. After the sanitary pit was capped, the continuous monitor in
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the same location disclosed an average concentration of 17.1 pCi/L over the next 27 days.
Prior to the installation of Phase 2, a continuous monitor was again placed in the basement
family room for a period of approximately four days. The average hourly radon concentration during
that time was found to be 17.5 pCi/L. After the Phase 2 system was installed and activated, indoor
radon concentration rapidly fell to an average of 0.4 pCi/L over the next seven days.
A continuous trend plot illustrating the results of this testing can be found in Appendix A.
Follow-Up Monitoring
A number of tests using activated charcoal canisters and alpha-track detectors were conducted
at this home after the installation of Phase 2 to determine the long-term average radon concentration.
Results of all the tests performed at this home can be found in Appendix A Alpha-track detectors
disclosed average radon concentrations of 2.9 pCi/L in the basement and 1.4 pCi/L on the first floor
during the period beginning on February 2, 1988 and ending February 28, 1989. During this time
period the wall depressurization system was operating continuously. Figure 2.1-1 presents data
gathered during all phases of the project.
Mitigation System Costs
The mitigation contractor's cost for installation of both phases of work at this home was
$2,037.90. This included $291.90 for materials and $1,746.00 for labor. The high labor cost can be
attributed to the additional work involved with excavating the pipe trench.
Discussion
In spite of the elevated radon concentrations found in the sanitary clean-out pit, sealing the
pit had little or no impact on the indoor radon concentrations. Two possible explanations have been
discussed. The first theorizes that even though the pit contained high radon concentrations, the
airflow between the pit and the basement was low. This would cause the pit to contain high levels
but be a minor contributor to the overall radon concentration. The second possibility is that by
sealing the pit, the radon was merely forced to find some other entry point that was not sealed.
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2.2 HOUSE AR-04
House Description
This wood-framed split-level home was constructed on a level lot in a subdivision during 1971.
The substructure consists of a combination basement/slab-on-grade foundation with hollow-core
masonry walls and poured concrete floor slab. The top course of the block walls is solid blocks. The
basement is used as a laundry and workshop.
Combustion appliances in the basement area include a gas-fired forced-air furnace, gas-fired
domestic hot water heater, and a vented clothes drier. There are no provisions in this home to supply
dedicated combustion make-up air to any of the combustion devices.
Initial screening tests performed in early November 1986, disclosed an average concentration
of 23.9 pCi/L in the basement. Additional screening tests performed during December 1986 disclosed
average concentration's of 11.9 pCi/L on the first floor and 11.1 pCi/L on the second floor.
Diagnostic Testing Results/Interpretation
Diagnostic testing was performed during February 1987. Radon grab sample measurements
were taken from within the hollow-core block walls and from beneath the basement floor slab.
Analysis of these samples revealed radon concentrations ranging from 160 to 667 pCi/L within the
walls and 126 pCi/L beneath the floor slab.
Communications testing revealed good connectivity beneath the floor slab, marginal
connectivity between the slab and foundation walls, and good connectivity from wall to wall. The
sub-slab aggregate was found to be gravelly soil. The floor slab was cracked in numerous places with
some large cracks evident. The foundation walls had minor cracks and holes. There were no
designated floor penetrations such as drains or sump holes.
Based upon the diagnostic testing results, initial mitigation plans prescribed a two-phase
approach at this home. Phase 1 would involve the installation of a sub-slab depressurization system
using a centrifugal blower. Because some communications existed between the sub:slab area and the
foundation walls, it was expected that a sub-slab depressurization system would develop a negative
pressure field beneath the floor slab that would extend up into the foundation walls. No sealing of
floor or wall penetrations would be performed during this phase. Phase 2 would provide for the
coupling of a wall depressurization system with the sub-slab system. Sealing of floor and wall
penetrations would also be done during this phase.
2.2-1
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Pre-Mitigation Testing
A continuous radon monitor was placed in the basement at Location 1 (see Appendix A)
approximately six days prior to the installation of the Phase 1 sub-slab depressurization system. The
basement radon concentration averaged 22.8 pCi/L during this time period.
Mitigation System Installation
The sub-slab depressurization system was installed during the first week of April 1987. A
four-inch diameter hole was bored through the floor slab. PVC piping was used as an exhaust
manifold. A Kanalflacht centrifugal blower powered the depressurization system. Pressure and
airflow measurements made after the installation disclosed a pressure field extension beneath the slab
that was not consistent with what was expected based upon the communications test results. It was
suspected that the penetration point was placed in an area where the sub-slab aggregate had a lower
permeability than where the communications testing was performed.
Phase 2, the addition of a tap to connect the common block wall to the sub-slab
depressurization system, was installed on April 9, 1987. Due to the poor pressure field extension
developed by the Phase 1 penetration point placement, the slab penetration point was moved closer
to the common block wall. To install the wall tap, the exhaust pipe leading from the floor slab
penetration was cut and fitted with a tee fitting. A short piece of PVC pipe was then connected to
the tee and run to a penetration made through the interior of the common block wall. It should be
noted that the penetration was made through the interior surface of the block wall only, and not
completely through the wall. The reason for this was the desire to provide depressurization to the
interior of the block wall and not to the soil beneath the slab-on-grade area. All accessible floor and
wall penetrations were sealed at this time using non-shrink grout or polyurethane caulk.
Short-Term Results
Immediately after the activation of the Phase 1 sub-slab depressurization system, the basement
radon concentrations rapidly fell to an average of 13.2 pCi/L over the next eight days. Immediately
after the wall depressurization tap was connected to the sub-slab depressurization system, the
basement radon concentrations decreased to a six-day average of 2.2 pCi/L, disclosed by a continuous
monitor placed in the basement. The continuous trend plot representing the data can be found in
Appendix A of this report.
2.2-2
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Follow-Up Monitoring
Numerous measurements were taken after the installation of the Phase 2 mitigation system
using both activated charcoal and alpha-track methods. These data are presented in Appendix A
Radon concentrations during the period beginning February 2, 1988 and ending February 28, 1989,
disclosed average concentrations of 1.9 pCi/L in the basement and 0.8 pCi/L on the first floor. All
tests performed on the second floor with the Phase 2 system installed measured an averaged of 1.1
pCi/L.
Mitigation System Costs
The cost for installing the Phase 1 system was $1,239.09, of which $1,000.00 was for labor.
The Phase 2 total was $535.00, of which $500.00 was for labor.
Discussion
Although the diagnostic testing indicated a potential for the sub-slab depressurization system
to also depressurize the walls, this was not achieved. This was because of the original placement of
the slab penetration point discussed above. After the penetration point was moved, it was suspected
that sealing the floor and wall penetrations could assist the development of a negative pressure field
extension into the walls. To determine this, the floor and wall penetrations were sealed and pressure
fields checked before the common block wall was penetrated. No pressure field could be detected
in the block wall using magnehelics or smoke sticks. Also no increase in pressure field beneath the
floor slab was noted. This indicated that the cracks in the floor had little effect on the operation of
the sub-slab depressurization system in this particular house. In fact, examination of the cracks
indicated that soil gas was still flowing into the basement through these cracks, even while the
sub-slab depressurization system was operating. These cracks and the fact that the block walls
contained high concentrations of radon, were the major reasons why the Phase 1 sub-slab
depressurization system achieved only moderate reductions.
The addition of the wall depressurization tap developed a negative pressure field within the
common block wall that extended across most of the wall. In fact, smoke could be observed entering
an adjoining wall through a test hole approximately 15 feet away from the wall penetration point.
This wall depressurization, working in conjunction with the sub-slab depressurization, effectively
maintained long-term radon concentrations below the 4 pCi/L level. Figure 2.2-1 presents a
phase-by-phase comparison of radon measurements.
2.2-3
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MONITORING CONDITION
SAMPLING METHOD
Figure 2.2-1. House AR-04. Comparison of Radon Measurements by Phase.
2.2-4
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2.3 HOUSE AR-05
Building Description
This single family split-level house was built on a level lot in the same subdivision as were the
previously discussed homes. The substructure of the wood-framed home consists of a combination
basement and slab-on-grade foundation. The basement foundation walls are constructed of
hollow-core masonry blocks with the top course of solid core blocks. The 575 sq. ft. basement floor
slab averages approximately 5 feet below-grade and is primarily used as a laundry and storage area.
The 550 sq. ft. slab-on-grade section contains a family room and small attached garage that is used
for additional storage area. Combustion appliances in the basement include a gas-fired forced-air
furnace and a gas-fired domestic hot water heater. The clothes drier is vented to the outside.
Neither appliances are supplied with dedicated outside combustion make-up air.
Initial screening tests using charcoal canisters revealed a basement concentration of 32.0
pCi/L. Additional charcoal samplers were used on the first and second floors approximately three
weeks after the first testing. These tests disclosed average concentrations of 23.0 pCi/L on the first
floor and 14.5 pCi/L on the second.
Diagnostic Testing Results/Interpretation
Initial diagnostic testing was performed in February 1987. Radon grab samples were taken
from beneath the basement floor slab and from within the concrete block foundation walls. Sub-slab
concentrations were found to be 782 pCi/L. A grab sample taken from a large hole in the slab
disclosed a concentration of 290 pCi/L. Foundation wall radon concentrations ranged from less than
1 pCi/L to a high of 586 pCi/L. The locations of these grab samples can be found on the diagnostic
measurements map in Appendix A
Communications testing revealed good communications beneath the basement floor slab and
within individual foundation walls. Communications from beneath the floor slab to the foundation
walls was marginal. The sub-slab aggregate was found to be a gravelly soil much like that beneath
all of the homes in this subdivision that participated in this project.
Based upon the data gathered during the diagnostic testing, initial mitigation plans prescribed
a three-phase approach. Phase 1 involved the installation of a sub-slab depressurization system using
a centrifugal blower. Because some communications existed between the sub-slab area and the
foundation walls, it was expected that a sub-slab depressurization system would develop a negative
pressure beneath the floor slab that would extend up into the foundation walls. No sealing of floor
2.3-1
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or wall penetrations would be performed during this phase. Phase 2 provided for the coupling of a
wall depressurization system with the sub-slab system. Sealing of floor and wall penetrations would
not be done during this phase. Phase 3 would provide for the sealing of floor and wall cracks and
penetrations.
Pre-Mitigation Testing
Immediately prior to the start of the Phase 1 installation a continuous radon monitor was
placed in the basement. The average radon concentration during this short (1 day) period was found
to be 21.3 pCi/L. A longer-term test using alpha-track detectors was made during February, March,
and part of April 1987. Average radon concentrations during this period were found to be 21.7 pCi/L
in the basement and 16.2 pCi/L on the first floor. The results of the long-term tests was used as the
pre-mitigation concentrations in this home.
Mitigation System Installation
The Phase 1 sub-slab depressurization system was installed and activated on April 24, 1987.
The system used an in-line centrifugal blower to provide active depressurization. As in all systems
using centrifugal blowers in this study, four-inch PVC pipe was used to duct the soil gases to the
outside.
The Phase 2 sub-slab/wall depressurization system was installed on the afternoon of April 27,
1987. As in house AR-04, a hole was drilled through the basement side of the concrete block wall.
A short length of PVC pipe was connected to a "Tee" fitting that had been placed in the sub-slab
depressurization system pipe. The depressurization of the sub-slab area and the common block wall
could then be provided by one common centrifugal blower.
In early March 1988, floor and wall penetrations were sealed. This sealing, combined with
the Phase 2 system, constituted the Phase 3 effort.
Short-Term Results
A continuous radon monitor placed in the basement revealed that the sub-slab
depressurization system lowered the radon concentrations to an average of 4.2 pCi/L for two days
after activation of the Phase 1 system. Phase 2 lowered the basement concentrations to a one-day
average of 1.9 pCi/L. No continuous short-term concentrations were available for Phase 3.
2.3-2
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Follow-Up Results
Alpha-track detectors were deployed in the home during the period between the installation
of Phases 2 and 3. During one time period extending from September 21, 1987 to February 2, 1988,
radon concentrations averaged 10.9 pCi/L in the basement, 6.1 pCi/L on the first floor, and 5.9 pCi/L
on the second floor. Homeowners report that the mitigation system fan was shut off for an
undetermined period during these tests. This could account for the elevated radon concentrations.
During the period of February 2 to March 29, 1988, additional alpha-track detectors were placed in
the basement, and on the first and second floors. The fan was operating during this entire time
period, however, these measurements also included a period when the Phase 3 sealing was completed
so accurate indications of the combined sub-slab/wall depressurization results cannot be determined.
After the Phase 3 sealing efforts were completed, alpha-track detectors were again deployed in the
home. Radon measurements made during one period extending from March 29 to June 17, 1988
disclosed an average concentration of 6.1 pCi/L in the basement and 1.6 pCi/L on the first floor.
Subsequent alpha-track detectors placed in the basement from June 17 to November 18, 1988
indicated an average concentration of 16.5 pCi/L. Once again, the fan was shut off by the
homeowners during an unknown period when these measurements were made. An additional set of
alpha-track detectors deployed from November 18, 1988 to February 28, 1989 disclosed an average
concentration of 0.7 pCi/L in the basement, 0.9 pCi/L on the first floor, and 0.8 pCi/L on the second.
Mitigation System Costs
The mitigation contractor's cost for the installation of the Phase 1 system was $1,177.09, of
which $1,000.00 was for labor and $177.09 for materials. The Phase 2 system improvements cost an
additional $540.18, of which $500.00 was for labor and $40.18 for materials. The Phase 3 mitigation
system additions cost another $591.10, of which $582.00 was for labor and $9.10 for materials.
Discussion
Due to the short duration of the continuous measurements taken during the Phase 1 and 2
periods, it is difficult to claim any success. Other factors could have resulted in the decrease in radon
concentrations. However, analysis of the continuous trend plots that can be found in Appendix A
shows that radon concentrations dropped rapidly beginning on the hour that each phase was
activated. The fan being off for a period of time during Phase 2 and Phase 3 also tends to cloud the
overall results of each phase. However, the other measurements made with the fan operating
2.3-3
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continuously indicate that the home will maintain a long-term average below 4 pCi/L if the fan is left
operating.
2.3-4
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Figure 2.3.1 House AR-05. Comparison of Radon Measurements by Phase.
23-5
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2.4 HOUSE AR-09
Building Description
This split-level wood-framed home was built in 1968 on a level lot in the same subdivision as
the previously described homes. The home rests on a combination basement/slab-on-grade
substructure. The floor slab is poured concrete. The foundation walls are constructed of hollow-core
masonry blocks. The cores of the top course of blocks are filled with mortar. The 400 sq. ft.
basement floor slab averages approximately 5 feet below-grade and contains minor cracks. The 300
sq. ft. slab-on-grade section is covered with carpeting and linoleum and could not be checked for
cracks.
Combustion appliances in the basement include a gas-fired hot water boiler and a gas-fired
domestic hot water heater. There are no provisions for dedicated outside combustion supply air for
these two appliances.
Initial screening tests made with activated charcoal canisters revealed an average basement
concentration of 20.9 pCi/L in early November 1986. Additional charcoal tests performed in
December 1986 disclosed average concentrations of 3.4 pCi/L on the first floor and 3.1 pCi/L on the
second.
Diagnostic Testing Results/Interpretation
Initial diagnostic testing was performed in February of 1987. Radon grab samples were taken
from the interior of the hollow-core block foundation walls and from beneath the floor slab. Sub-slab
radon concentrations ranged from 87 pCi/L taken from a hole near the center of the basement to
168 pCi/L taken from a hole in the slab close by a exterior foundation wall. Wall samples ranged
from 1.6 pCi/L in one exterior wall to 711 pCi/L in the wall common to the basement and
slab-on-grade areas. The visual inspection of the home revealed minor floor cracks and relatively
large wall cracks. Communications testing revealed good sub-slab, fair wall-to-wall, and marginal
slab-to-wall communications. The basement was pressurized using a blower door. Reversal of the
normal sub-slab to basement flow of air was observed at a pressure of 8 Pascals and an airflow rate
of 72 cfm.
From the data gathered during the diagnostic testing, four phases were prescribed for this
home. Phase 1 involved the installation of a sub-slab depressurization system using a centrifugal
blower. Phase 2 combined the Phase 1 sub-slab depressurization system with a block wall
depressurization system and the sealing of floor and wall penetrations. Phase 3 required the
2.4-1
-------
deactivation of the depressurization systems and relied on sealing alone as a radon reduction
technique. Finally, Phase 4 would involve pressurizing the basement area with upstairs air.
Pre-Mitigation Monitoring
A continuous radon monitor was placed in the basement in late April 1987 to determine the
concentrations prior to the Phase 1 sub-slab system installation. This monitoring disclosed an average
concentration of 22.5 pCi/L. Due to problems with the homeowner's agreement forms, all phases of
work were delayed until September 1987. All measurements made prior to any mitigation work
indicated average concentrations exceeding 20 pCi/L in the basement. The initial screening
measurement of 20.9 pCi/L will be used as a pre-mitigation concentration for this home.
Mitigation System Installation
Phase 1, the installation of the sub-slab depressurization system, was to have begun on April
28, 1989. However, rejection of the homeowner's agreement forms and proposed mitigation systems
by the homeowner delayed the installation until November. When approval was given by the
homeowners to begin work, the mitigation system was immediately installed.
The Phase 2 installation of the wall depressurization system and the sealing of floor and wall
penetrations began on November 5.
On November 17, the sub-slab depressurization systems were deactivated and the exhaust
pipes blocked to prevent any possibility of passive depressurization. This action would provide data
on the results of sealing radon entry points as a stand-alone mitigation technique.
Phase 4, the installation of a basement pressurization system was delayed until fans acceptable
to the homeowners could be procured. The fan was installed in a first floor closet, which would draw
air from the first floor and exhaust into the basement. The system was equipped with a smoke
detector/relay system that would deactivate the system in the event of a fire. After the installation,
system diagnostics revealed that the system was pressurizing the basement and that air was flowing
out of the basement rather than in. Unfortunately, the homeowners strongly objected to the use of
this system and the system was removed; therefore, no radon data are available for this phase.
2.4-2
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Short-Term Results
Once the homeowner's agreement forms were accepted, installation of the mitigation systems
immediately began; therefore, no radon concentrations immediately prior to the installation of Phase
1 are available. The installation of Phase 1 was started and completed on November 3, 1987. With
the sub-slab system operating, continuous radon monitors disclosed an average concentration of 1.5
pCi/L in the basement and 0.5 pCi/L on the Grst floor for a short period of two days after the
installation.
After the installation of the Phase 2 system, continuous radon monitors in the basement and
on the first floor disclosed average radon concentrations for a 12-day period of 0.4 and 0.3 pCi/L
respectively.
With the Phase 3 system operating, continuous monitors indicated a rapid increase in radon
concentrations on both floors, where an average of 9.9 pCi/L was measured in the basement and 2.2
pCi/L on the first floor. This experiment was run for approximately three days and then the
sub-slab/wall depressurization system was reactivated. Radon concentrations rapidly fell to a 19-day
average of 0.2 pCi/L in the basement and 0.3 pCi/L average on the first floor.
Follow-Up Results
Long-term monitoring of radon concentrations using alpha-track detectors revealed average
concentrations of 1.7 pCi/L in the basement, 0.7 pCi/L on the first floor, and 0.8 pCi/L on the second
floor from January 14, 1988 to November 18, 1988. During that time period, the Phase 2
sub-slab/wall depressurization system was operating continuously.
Mitigation System Costs
The Phase 1 mitigation system, which included the installation of the sub-slab depressurization
system, cost $1,216.00, of which $1,000.00 was for labor and $216.00 for materials.
Phase 2 costs, which involved sealing floor and wall penetrations and the addition of a wall
depressurization tap to the Phase 1 system, totalled $611.00, of which $582.00 was for labor and
$29.00 was for materials.
There was no cost associated with Phase 3 as it only required the deactivation of the
depressurization systems by turning off the fan and plugging the exhaust pipe with duct tape.
The basement pressurization system installed during Phase 4 cost $594.24, of which $388.00
was for labor and $206.24 was for materials.
2.4-3
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Discussion
The Phase 1 system decreased indoor radon concentrations below the 4 pCi/L guideline, at
least for the short-term. It is suspected that this system alone would have maintained radon
concentrations below 4 pCi/L.
Radon concentrations decreased after the addition of the wall depressurization during Phase
2. Investigation of the continuous trend plot in Appendix A does indicate that the Phase 2 system
most likely was the cause of this reduction rather than some outside parameter.
Clearly the Phase 3 technique of sealing radon entry points as a stand alone mitigation system
was not effective enough to maintain radon concentrations below 4 pCi/L. It is unfortunate that the
homeowners objected to the use of the basement pressurization system installed during Phase 4. This
mitigation technique should be fully tested.
2.4-4
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32
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2.5 HOUSE AR-16
Building Description
This newly constructed Cape Cod style home was built on a sloping lot. The home rests on
a foundation constructed of poured concrete walls with a poured concrete floor slab. Three sides of
the foundation average five feet below-grade. The fourth side is mainly on-grade with a small portion
of this wall having the ground sloping up a few feet to form a small berm against the wall. The
on-grade side has operable windows and an exit to the outside. The unfinished basement is used
mainly for storage but has interior partition framing in place for the installation of a bathroom and
workshop area. The poured concrete floor slab has designed penetrations including a sump, French
drain, and an expansion joint through the center of the slab. The French drain and an interior
perimeter footing drain are connected to the sump.
Combustion appliances in the basement include an oil-fired hydronic boiler and a gas-fired
domestic hot water heater. These appliances use the basement air for combustion as there are no
provisions for external or outside supply air to be ducted to these appliances for combustion.
Diagnostic Testing Results/Interpretation
Diagnostic testing was performed during February 1987. Radon grab samples were taken in
the French drain, from within the sump, and from beneath the slab at the expansion joint. Analysis
of these samples indicated a concentration of 468 pCi/L in the expansion joint, 168 pCi/L in the sump
hole, and 12 pCi/L in the French drain. Communications testing indicated good sub-slab
communications and good connectivity between the French drain and the sub-slab area.
The mitigation strategy for this home would include installing a footing drain depressurization
system using the sump hole for the slab penetration point. The sump would be provided with an
airtight cover. Phase 2 would involve sealing of the French drain and expansion joint. The footing
drain depressurization system would be deactivated and the exhaust pipe capped. Phase 3 would
reactivate the footing drain depressurization system to indicate the effect of sealing the French drain
and expansion joint on the overall radon reduction.
Pre-Mitigation Monitoring
Initial screen testing performed during early November 1986 disclosed a radon concentration
averaging 32.6 pCi/L in the basement. Alpha-track detectors deployed at the home from late
February to early April 1987 disclosed average radon concentrations of 10.6 pCi/L and 1.6 pCi/L in
2.5-1
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the basement and on the first floor respectively. A continuous monitor placed in the basement
indicated an average of 15.5 pCi/L during the period of March 17-31, 1987.
Mitigation System Installation
The Phase 1 installation began in late March 1987. An airtight cover of exterior grade
plywood was fitted over the sump hole. Active ventilation was provided by a centrifugal blower. On
the afternoon of March 31, the depressurization system was activated. System diagnostics revealed
that the interior footing drain was channeling the pressure field around the perimeter of the building.
As was expected, leakage was evident around the French drain.
The sealing of the French drain and expansion joint was performed on April 7, 1987. Backer
rod and pourable polyurethane caulk were used to seal the French drain. This sealing was done in
such a way as to keep the French drain operable, but stop the influx of radon-laden soil gases. The
expansion joint was also filled with polyurethane caulk. The use of polyurethane caulk was
considered especially appropriate in the expansion joint because of the caulk's adhesion and flexibility
characteristics. These characteristics provided an airtight seal in the expansion joint but still allowed
for slab movement. The footing drain depressurization system was deactivated and the exhaust pipe
was capped after the sealing was completed.
The Phase 3 system, which required the removal of the exhaust pipe cap and reactivation of
the footing drain depressurization system was performed on the afternoon of April 15. At this time,
all continuous monitors were removed from the field for participation in Round 4 of the RMP.
Because of this, there are no continuous measurements available. However, long-term follow-up
measurements were performed.
Short-Term Results
Prior to the installation of the Phase 1 system, a continuous radon monitor was placed in the
basement area for a two-week period. Radon concentrations over this period averaged 15.5 pCi/L.
Radon concentrations in the basement area began to fall immediately after activation of the system
to an average of 0.8 pCi/L over the next seven days.
After the depressurization system was deactivated, and the Phase 2 sealing completed, radon
concentrations, as disclosed by the use of a continuous radon monitor in the basement, slowly rose
to an average of 5.7 pCi/L over the next nine days.
No short-term continuous measurements were performed during Phase 3.
2.5-2
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Follow-Up Measurements
A series of long-term radon measurements using alpha-track detectors were performed from
January 9, 1988 to March 1, 1989. Radon concentrations averaged 2.3 pCi/L in the basement, 0.8
pCi/L on the first floor, and 0.6 pCi/L on the second floor during that period.
Mitigation System Costs
The Phase 1 mitigation system, which included the installation of the sump and interior
footing drain depressurization system, cost $956.00, of which $750.00 was for labor and $206.00 was
for materials.
The Phase 2 costs, which involved sealing all cracks and penetrations in the basement, totalled
$600.00, of which $500.00 was for labor and $100.00 was for materials.
There was no cost associated with Phase 3 as it only required re-activating the
depressurization system.
Discussion
The Phase 1 depressurization system decreased the radon concentrations considerably. An
inspection of the French drain revealed that air was being drawn from the basement to the sub-slab
area by the depressurization system. It is not known whether this situation would have caused
long-term concentrations to exceed 4 pCi/L, but the loss of conditioned air would have resulted in
increased heating costs.
With the depressurization system deactivated, the radon concentrations slowly increased.
While it is not known if the long-term average concentration would have exceeded 4 pCi/L, it is
considered to be very likely.
2.5-3
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PHASE 1
PHASE 2
PHASE 3
MONITORING CONDITION
SAMPLING METHOD
Figure 2.5-1. House AR-16. Comparison of Radon Measurements by Phase.
2.5-4
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2.6 HOUSE AR-17
Description
This wood framed Cape Cod style home was built on a level lot in a subdivision during 1984.
The home rests on a poured concrete foundation. The 950 sq. ft. basement floor slab is poured
concrete and averages approximately six feet below-grade. Designed penetrations include a three sq.
ft. hole in the floor slab, and a French drain. This hole is not a typical sump but merely an area
where the slab was not poured, possibly to be used for a sump if drainage were required. There are
no combustion appliances in the basement area.
Initial screening tests performed from November 10 to November 14, 1986 disclosed an
average concentration of 51.8 pCi/L in the basement. Additional testing performed from December
12 to December 17, 1986 revealed average radon concentrations of 36.1 pCi/L in the basement, 13.3
pCi/L on the first floor, and 11.9 pCi/L on the second floor.
Diagnostic Testing Results/Interpretation
Initial diagnostic testing was performed in February 1987. Grab samples taken from beneath
the floor slab revealed a surprisingly low concentration of 27 pCi/L. A grab sample taken in the
sump revealed a concentration of 114 pCi/L. Communications testing revealed marginal sub-slab
communications. Minor cracks were noted in the slab.
Based upon data gathered during the diagnostic testing, the mitigation strategy for this home
would include five phases. Phase 1 would involve depressurizing the sump hole. Phase 2 would
deactivate the sump depressurization system and pressurize the basement with upstairs air. Phase 3
would employ sealing techniques as a stand alone reduction method. Phase 4 would activate the
sub-slab depressurization system to determine if sealing improved the effectiveness of the system, and,
finally, Phase 5 would reactivate the basement pressurization system to determine any additional
reduction due to the sealing of floor penetrations.
Pre-Mitigation Monitoring
A continuous radon monitor was placed in the basement on April 1, 1987, and allowed to
collect data until April 25. Radon concentrations averaged 28.4 pCi/L during that time period. The
Phase 1 mitigation system was to be installed the last week in April, but problems with the
homeowner's agreement forms delayed the installation until early fall. When the problems were
resolved, a continuous monitor was placed in the basement on September 21, 1987 to record
2.6-1
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pre-mitigation radon levels. Radon concentrations over the next three days averaged 23.6 pCi/L.
Mitigation System Installation
The Phase 1 sump depressurization system was installed on September 23, 1987. A plywood
cover was sealed to the top of the floor slab, covering the sump hole. An active depressurization
system was connected to the plywood cover and ducted through four inch PVC pipe to the outside.
Active depressurization was provided by an in-line centrifugal fan (Kanalflakt K-4).
On February 23,1988, the Phase 2 basement pressurization system was installed and activated.
Air from the upstairs portion of the home was drawn into the basement by a fan at a volume of
approximately 180 cfm. This resulted in a basement pressure that was approximately 10 Pa positive
relative to the sub-slab air pressure. A smoke detector equipped with a normally closed relay was
connected to the fan in case of fire. In this way, if the smoke alarm sounded, the fan would be
turned off.
The sealing of the French drain and floor cracks which constituted the Phase 3 mitigation
efforts was completed in late March. Foam backer rod and pourable polyurethane caulk were used
to seal the French drain. The floor cracks were cleaned and filled with non-shrink grout.
The Phase 4 and 5 systems involved no additional work by the mitigation contractors. The
homeowners started and stopped these phases and kept a log of the start and stop times for the
investigators.
Short-Term Results
Immediately after the Phase 1 sump depressurization system was installed and activated, radon
concentrations rapidly fell to an average of 2.2 pCi/L over the next seven days.
The Phase 2 basement pressurization system was run for a period of 17 days, beginning
February 23 and ending March 11, 1988. The average basement radon concentration during this
period was 0.5 pCi/L.
In the later part of April, 1988, the homeowners operated the various systems to gather the
Phase 3, 4, and 5 data. On April 22, the sump depressurization system was activated. This, along
with the sealing, constituted Phase 4. The system was operated for five days in that manner. Radon
concentrations averaged 1.6 pCi/L during that period. On April 24, the homeowners turned off the
fan to determine the effect that sealing the French drain and floor cracks had on the indoor radon
concentrations. The homeowners also sealed the end of the depressurization system exhaust to
2.6-2
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prevent any passive depressurization. The fans were left off for less than two days because the
homeowners grew alarmed at the increase in radon concentrations in the basement. Concentrations
averaged 9.1 pCi/L with sealing as the only mitigation technique. The homeowners then reactivated
the basement pressurization fan. Basement radon concentrations averaged 0.5 pCi/L over the
following two days.
Follow-Up Measurements
A series of long-term measurements made with alpha-track detectors were performed with
the basement pressurization system operating. Concentrations averaged 1.9 pCi/L in the basement,
0.9 pCi/L on the first floor, and 0.7 pCi/L on the second floor from June 8, 1988 to March 1, 1989.
Mitigation System Costs
The Phase 1 mitigation system, which included the installation of the sump depressurization
system, cost $1,200.00 of which $1,000.00 was for labor and $200.00 was for materials.
Phase 2 costs, which involved pressurizing the basement using upstairs air while the
depressurization system was de-activated, totalled $819.00, of which $582.00 was for labor and $237.00
was for materials.
Phase 3 costs, which included sealing all cracks in the basement including around the French
drain, totalled $600.00, of which $500.00 was for labor and $100.00 was for materials.
There were no costs associated with Phases 4 and 5 as the homeowner operated the
mitigation systems to provide the required data.
Discussion
The Phase 1 sump depressurization system performed well, in spite of the marginal sub-slab
communications. Surprisingly, the basement pressurization system worked extremely well. Radon
concentrations were maintained below 4 pCi/L for nearly one year, and the homeowners expressed
satisfaction with this system. Of interest is the fact that the fan was identical to the one used at
house AR-09 where the homeowners strongly objected to the noise made by the fan.
2.6-3
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2.7 HOUSE AR-19
House Description
This single family wood-framed home was built on a level lot in a subdivision in 1969. The
home rests on a poured concrete foundation with a poured concrete floor slab. The 1040 sq. ft.
basement is used for storage. Designed penetrations in the walls include several utility penetrations.
There are no designed penetrations in the floor slab.
Combustion appliances in the basement include a gas-fired hot water boiler and a gas-fired
domestic hot water heater.
Initial screening tests performed with charcoal canisters from November 14 to November 18,
1986 indicated a basement radon concentration of 34.7 pCi/L.
Diagnostic Testing Results/Interpretation
Initial diagnostic testing was performed in February 1987. Radon grab samples taken from
beneath the floor slab averaged 550 pCi/L. A grab sample taken from a wall penetration disclosed
a radon concentration of 275 pCi/L. Communications testing beneath the floor slab indicated
marginal communications. Large floor cracks were evident across a significant portion of the
basement.
Based upon data collected during the diagnostic testing, it was decided that the Phase 1
mitigation system would involve depressurizing beneath the floor slab using a centrifugal fan. Phase
2 would require sealing the floor and wall cracks and penetrations. The depressurization system
would be deactivated during this phase to determine the effect of sealing as a stand alone mitigation
system. Phase 3 would reactivate the sub-slab depressurization system.
Pre-Mitigation Testing ,
A continuous radon monitor was placed in the basement on April 24, 1987 to collect radon
concentration data immediately prior to the installation of the Phase 1 system. Radon concentrations
during that period averaged 30.4 pCi/L. Alpha-track detectors that had been placed in the home
during the diagnostic testing visit, and retrieved in early April, revealed average concentrations of 12.3
pCi/L in the basement and 2.2 pCi/L on the first floor.
Mitigation System Installation
Installation of the Phase 1 sub-slab depressurization system began on April 29, 1987. As the
2.7-1
-------
mitigation contractors were about to wire the system, the homeowner decided that he no longer
wished to participate in the project. Negotiations with the homeowner resulted in the homeowner
finishing the system himself.
Short-Term Results
No short-term results are available for this home.
Follow-Up Monitoring
Alpha-track detectors placed in the home from February 1, 1988 to March 1, 1989, revealed
an average radon concentration of 20.0 pCi/L in the basement, 1.3 pCi/L on the first floor, and 2.0
pCi/L on the second floor.
Mitigation System Costs
The mitigation contractor's cost for the installation of the Phase 1 system totalled $1,100.00.
Of this total, $900.00 was for labor and $200.00 was for materials.
Discussion
Although the homeowner declined to participate in the project, he did finish installing the
sub-slab depressurization system, and allowed the investigators to inspect the installation and perform
follow-up testing.
During the subsequent visits to the home, system diagnostics testing was performed. This
testing indicated that the floor cracks were "short circuiting" the sub-slab depressurization system.
Ideally, all of the air that the fan in a sub-slab depressurization system can move should come from
beneath the floor slab. In the case of House AR-19, most of the air that was being moved by the
fan came from the basement through the floor cracks. This resulted in an ineffective sub-slab
depressurization system.
2.7-2
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Figure 2-7.1. House AR-19. Comparison of Radon Measurements by Phase.
2.7-3
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2.8 HOUSE AR-20
Description
This single family wood-framed ranch with full basement was built on a level lot in a
subdivision during 1980. The house rests on a poured concrete foundation with a poured concrete
floor slab. The slab averages approximately five feet below-grade. Designed penetrations in the slab
include a sump hole and perimeter French drain. A complete interior footing drain is connected to
the sump.
There are no combustion appliances in the basement.
Initial screening tests performed in November 1986 revealed an average basement
concentration of 60.6 pCi/L. Additional tests performed the following month indicated an average
concentration of 20.0 pCi/L on the first floor.
Diagnostic Testing Results/Interpretation
Initial diagnostic testing was performed during February 1987. Radon grab samples taken
from the sump hole indicated a concentration of 320 pCi/L. Samples taken from beneath the floor
slab revealed a concentration of 49 pCi/L. Inspection of the floor slab and walls revealed minor
cracks. Communications testing indicated good communications beneath the slab. Based on the
diagnostic test results, it was decided that the Phase 1 mitigation system would involve the installation
of a sump depressurization system. Phase 2 would involve sealing the French drain, floor and wall
penetrations. The Phase 1 depressurization system would be deactivated. Phase 3 would reactivate
the depressurization system.
Pre-Mitigation Testing
A continuous radon monitor was placed in the basement eight days prior to the start of the
Phase 1 depressurization system installation. Radon concentrations averaged 35.7 pCi/L during that
time period.
Mitigation System Installation
Installation of the Phase 1 depressurization system began on March 26, 1987. An airtight
cover made of exterior grade plywood was installed over the sump hole. Active depressurization of
the sump hole was provided by an in-line centrifugal fan.
On the afternoon of April 8, the mitigation contractor sealed the French drain, floor and wall
2.8-1
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cracks. The French drain was sealed using a foam backer rod and pourable polyurethane caulk. Wall
cracks were sealed with gun-grade polyurethane caulk. Floor cracks were cleaned and sealed with
non-shrink grout. The Phase 1 depressurization system was deactivated.
The Phase 3 system required reactivating the depressurization system.
Short-Term Results
Immediately after the activation of the depressurization system, radon concentration fell to
a 13 day average of 2.3 pCi/L. Radon concentrations rapidly increased with the Phase 2 system to
a seven day average of 9.3 pCi/1.
Follow-Up Results
Long-term measurements performed using alpha-track detectors from September 21,1987 to
March 1, 1989 revealed an average concentration of 6.7 pCi/L in the basement and 1.4 pCi/L on the
first floor.
Mitigation System Costs
The mitigation contractor's cost for the Phase 1 system totalled $906.00. Of that total,
$750.00 was for labor and $156.00 was for materials.
The total cost for the Phase 2 work was $600.00, of which $500.00 was for labor and $100.00
for materials.
There were no costs for the Phase 3 system.
Discussion
The mitigation system did not maintain the long-term basement radon concentrations below
4 pCi/L. This is somewhat surprising because system diagnostics indicated that the depressurization
system was operating well. The pressure field being developed by the system extended around the
entire perimeter of the home. It was suspected, but not proven, that leaks may have developed in
the exhaust pipe, which would allow radon to re-enter the basement area.
2.8-2
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Figure 2.8-1. House AR-20. Comparison of Radon Measurements by Phase.
2.8-3
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2.9 HOUSE OP-01
Description
This single family home was built in the early 1950's on a level lot in a subdivision. The
exterior walls of the home are constructed of concrete blocks that run continuously from the
basement floor slab to the attic. Portions of the walls at the basement level are constructed of solid-
core cinder blocks. Most blocks, however, are hollow. This may be true of the rest of the walls but
could not be determined without removing the interior finish. Investigation of the attic space
revealed that there was no rafter plate on the top course of blocks; therefore, a thermal by-pass
existed around the entire perimeter of the home, extending from the basement to the attic. The 860
sq. ft. basement floor slab is poured concrete and averages approximately five feet below-grade.
There is one floor drain in the basement that the homeowner keeps sealed with a rubber stopper.
The majority of the basement area is used for storage, laundry, and workshop areas. Approximately
25% of the basement is used for play and television viewing.
Combustion appliances in the basement area include an oil-fired boiler used to satisfy space
heating and domestic hot water requirements.
Initial radon testing performed during January and February 1986 revealed average
concentrations of 29.7 pCi/L in the basement, 11.8 pCi/L on the first floor, and 12.6 pCi/L on the
second floor.
Diagnostic Testing Results/Interpretation
Diagnostic testing was performed in November 1986. Radon grab samples taken from
beneath the floor slab averaged 737 pCi/L. The interior of the foundation walls averaged 122 pCi/L.
It was noted that the walls and floor slab contained many cracks and holes. Communications testing
revealed fair communications within the walls, marginal communications beneath the slab, and no
communications between the slab and foundation walls.
The grab samples taken during the diagnostic testing revealed high concentrations beneath
the slab and elevated concentrations within the walls. From these samples it was obvious that the
walls and sub-slab would need to be treated. Due to the marginal communications in the sandy soil
beneath the floor slab, it was decided that Phase 1 would demonstrate a sub-slab depressurization
system using a regenerative blower. Phase 2 would require the replacement of the Phase 1 system
with a sub-slab depressurization system using a centrifugal fan. Phase 3 would provide wall
depressurization. The installation of a separate centrifugal fan would tap into the back wall of the
2.9-1
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home below-grade. Phase 4 would involve running the sub-slab and wall depressurization systems
concurrently.
Pre-mitigation Testing
During the diagnostic testing, alpha-track detectors were placed on all floors and left in place
until the Phase 1 mitigation installation began. Radon concentrations for this period averaged 15.0
pCi/L in the basement, 7.1 pCi/L on the first floor and 6.9 pCi/L on the second floor.
Prior to performing any mitigation work, a continuous radon monitor was placed in the
basement. Radon concentrations for the six days prior to the installation of Phase 1 averaged 20.6
pCi/L. It must be noted that during this time the homeowners opened the basement windows for
approximately 24 hours.
Mitigation System Installation
The Phase 1 sub-slab depressurization system was installed and activated on January 22, 1987.
Active depressurization was provided by a regenerative blower. Four suction points were used in this
system. Each suction point was placed at the inside perimeter of the floor slab, roughly at the
mid-point of each wall.
On February 19, 1987, the Phase 1 system was removed and replaced with the Phase 2
sub-slab depressurization system using a centrifugal blower to provide active depressurization. For
this system, a single penetration point was used.
The Phase 3 wall depressurization system was installed in October 1987. This system involved
penetrating the outside of the back wall of the home and depressurizing the walls with a centrifugal
fan. Due to the open tops of the blocks, and the extensive efforts that would be required in order
to seal them, no effort was made to seal the block tops. It was expected that if a large enough fan
were used, an adequate negative pressure field could be developed. Some sealing of accessible wall
cracks was performed.
The Phase 4 mitigation system required operating the sub-slab and wall depressurization
systems concurrently. This phase was started on November 18, 1987.
Short-term Results
Two days after the installation of the Phase 1 system, a heavy snowstorm covered the area
with two feet of heavy, wet, snow. A combination of snow sliding off the roof, and the homeowners'
2.9-2
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shoveling snow from the driveway onto the exhaust pipe of the system, completely covered the end
of the exhaust. Radon concentrations during this period when the exhaust pipe of the system was
covered averaged 13.5 pCi/L. A trend plot illustrating the effects of the snow covered exhaust pipe
can be found in Appendix A. After the snow was cleared from the exhaust pipe, radon
concentrations averaged 11.0 pCi/L over the next nine days.
After the removal of the Phase 1 system, and the installation of the Phase 2 system, a
continuous radon monitor revealed an average basement concentration of 14.3 pCi/L. Although this
concentration is slightly higher than reached by the Phase 1 system, the Phase 2 system was left in
place.
The Phase 3 wall depressurization system maintained an average of 2.8 pCi/L in the basement
for a period of eight days after installation.
Phase 4, which involved depressurization of the sub-slab and walls, maintained a short-term
average of 3.3 pCi/L in the basement.
Follow-up Monitoring
A number of tests were performed using alpha-track detectors with the wall depressurization
system operating alone (Phase 3), and with the walls and sub-slab areas depressurized (Phase 4).
With the Phase 3 system operating, radon concentrations during the period beginning on October
14, 1987 and ending February 9, 1988 averaged 3.3 pCi/L in the basement, 2.9 pCi/L on the first
floor, and 1.1 pCi/L on the second floor. With the Phase 4 system operating, radon concentrations
during the period of February 9, 1988 through March 7, 1989 averaged 2.7 pCi/L in the basement,
1.3 pCi/L on the first floor, and 1.0 pCi/L on the second floor.
Mitigation System Costs
The Phase 1 system was installed by the diagnosticians, not by the mitigation contractor. Due
to this and the fact that other work was being performed by the diagnosticians, an accurate cost
cannot be obtained. However, materials were estimated at $400.00 and labor at $800.00.
The mitigation contractor's cost for the installation of the Phase 2 system was $1,241.69.
Labor accounted for $1,000.00 of this amount.
The mitigation contractor's cost for the installation of the Phase 3 system was $746.53, of
which $585.00 was for labor costs.
2.9-3
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Discussion
This home was probably the most difficult home to mitigate in the entire project. A
combination of poor sub-slab communications, and non-typical wall construction, required many hours
of research to be spent in order to devise installation procedures that had any chance of reaching the
4 pCi/L target level.
Sub-slab depressurization alone did not reduce the concentrations below 4 pCi/L. However,
long-term measurements with all systems operating have maintained concentrations below 4 pCi/L.
2.9-4
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E3 BASEMENT
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SAMPLING METHOD
Figure 2.9-1. House OP-01. Comparison of Radon Measurements by Phase.
2.9-5
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2.10 HOUSE OP-03
Description
This single family concrete block home was built by the owner in 1966 on a sloping lot. The
home rests on a foundation constructed largely of poured concrete, however, a small portion is
hollow-core concrete blocks. The house is earth-bermed on three sides, with the fourth or front side
at grade level. An exterior footing drain runs around the three bermed sides of the home. The
lowest level of the home contains a family room, bedroom, bath, utility, and one-stall garage. The
slab is covered with tile and wall-to-wall carpeting. Designed penetrations in the walls include several
pipe penetrations for water and electrical entrances.
Water is supplied by a private well. Radon concentrations in the well water were found to
exceed 380,000 pCi/L.
Initial screening tests revealed an average concentration of 57 pCi/L on the lower level.
Diagnostic Testing Results/Interpretation
Diagnostic testing was performed in November 1986. Grab samples were taken from within
the hollow-core foundation walls, from beneath the floor slab, and from pipe penetrations in the
walls. Wall communications were found to be good. Sub-slab communications were found to be
marginal.
The grab samples revealed a high concentration of radon in one of the pipe penetrations.
The hollow-core concrete walls contained concentrations close to those found in the ambient air and,
therefore, were not considered to be a source. Surprisingly, the sub-slab sample indicated very low
levels of radon. However, subsequent samples disclosed high concentrations. Due to the high
concentrations found in the water, it was decided that Phase 1 would involve treating the water with
a granulated activated charcoal filter. Phase 2 would involve sealing all accessible wall and floor
penetrations, Phase 3 would replace the charcoal filter with a water aeration unit, and Phase 4 would
depressurize under the slab using a centrifugal fan.
Pre-Mitigation Monitoring
Numerous radon measurements were made prior to the start of any mitigation work in this
home. Alpha-track measurements made during December 1986 and January 1987 revealed an
average concentration of 30.4 pCi/L on the lower level and 18.1 pCi/L on the upper level. A
continuous monitor was placed on the lower level on October 22, 1987 and left in place until the
2.10-1
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Phase 1 system was installed. Unfortunately, equipment malfunctions resulted in the loss of data for
a period of approximately two weeks immediately prior to the Phase 1 installation; therefore, the
average of the alpha-track measurements were used as the pre-mitigation concentration.
Mitigation System Installation
A filter charged with granulated activated charcoal was installed in the water supply line on
December 4, 1987. This filter was donated and installed by a water treatment manufacturing
company. The filter was placed in the supply line downstream from an existing water softener.
The Phase 2 sub-slab depressurization system was installed on March 9, 1988. System
diagnostics at that time indicated that a negative pressure field was being developed beneath the
entire home.
The Phase 3 water aeration system was installed on April 13, 1988.
Short-Term Results
After the Phase 1 activated charcoal filter was installed, a continuous monitor revealed
average concentrations of 24.8 pCi/L over the next six days. With the addition of the sub-slab
depressurization system, radon concentrations averaged 8.8 pCi/L. A continuous radon monitor
placed on the lower level revealed average radon concentrations of 6.0 pCi/L for seven days after the
installation of the Phase 3 water aeration unit.
Follow-Up Results
Long-term measurements using alpha-track detectors revealed average concentrations of 4.7
pCi/L on the lower level and 3.2 pCi/L on the upper level.
Mitigation System Costs
The Phase 1 installation costs were donated by the equipment manufacturer.
The mitigation contractor's cost for the installation of the Phase 2 sub-slab depressurization
system was $1,248.00, of which $1,000.00 was for labor and $248.00 was for materials.
The Phase 3 water aeration installation cost was $2,750.00, with labor costs accounting for
$750.00 of the total amount.
2.10-2
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Discussion
The activated charcoal filter installed for Phase 1 did not lower the indoor radon
concentrations below 4 pCi/L. However, the system did lower the concentrations considerably, and
spikes in the radon concentrations from water usage were all but eliminated. This data is presented
in graphical form in Appendix A. One unfortunate side effect resulting from the use of the charcoal
filter was an increase in gamma radiation emanating from the radon decay products collected in the
filter. Although this problem was discussed with the homeowners, they elected to keep the filter in
place because of the improvement in the taste of the water. It was decided to install the Phase 3
water aeration system upstream from the charcoal filter. In this way, the majority of the radon would
be removed from the water prior to it passing through the charcoal filter, and gamma levels would
decrease.
The Phase 2 sub-slab depressurization system, working in conjunction with the water
treatment systems, has not maintained long-term average concentrations on the lower level of the
home below 4 pCi/L. During subsequent visits to the home, pressure measurements made beneath
the floor slab were very ambiguous. During one visit, pressure measurements indicated the pressure
field was extending across the entire sub-slab area. On other visits this was not true. Investigation
of the sub-slab aggregate during the times when the pressure field was not extensive found high water
content in the soil. This would restrict development of the pressure field.
2.10-3
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Figure 2.10-1. House OP-03. Comparison of Radon Measurements by Phase.
2.HW
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2.11 HOUSE OP-05
Description
This single family wood-framed ranch with full crawl space was built in 1966 on a sloping lot.
The home rests on a foundation of open top hollow-core concrete blocks. A small portion of the
crawl space floor is covered with a poured concrete slab. The majority of the crawl space is filled
with exposed bedrock outcroppings.
Initial screening tests performed in September 1986 revealed an average concentration of 179
pCi/L on the first floor. Numerous follow-up measurements were made in the crawl space and on
the first floor. One set of measurements using alpha-track detectors disclosed a month-long average
concentration of 275 pCi/L in the crawl space and 172 pCi/L on the first floor.
Domestic water from this home is supplied by a private well. Radon concentrations in the
water supply were found to be in excess of 245,000 pCi/L.
Diagnostic Testing Results/Interpretation
Initial diagnostic testing was performed during November 1986. The crawl space floor was
mapped for gamma radiation levels and found to range from 70 to 200 microR/hr. Radon grab
samples taken from within the foundation walls averaged 384 pCi/L. A well sleeve contained over
3,700 pCi/L. Radon flux measurements revealed that exposed bedrock in the crawl space was
emanating radon at a rate of 129 picoCuries per square meter of rock every second (pCi/M2S).
Based upon data gathered during the diagnostic testing, it was clear that some method of
sealing the exposed bedrock must be considered, not only to stop radon emanation, but also to
decrease gamma radiation levels. It was first thought possible to pour concrete over the bedrock;
however, estimates made by concrete contractors exceeded $15,000. It was then theorized that much
of the gamma radiation was from the radon decay products, and a reduction in the radon levels would
also lower the gamma radiation levels. It was decided, therefore, that Phase 1 would involve covering
the exposed bedrock with a poly film and depressurizing beneath the film. Phase 2 would combine
wall dcpressurization with the Phase 1 system. The open tops of the concrete blocks and all wall
penetrations would also be sealed. Phase 3 would involve the installation of a water aeration unit
to remove radon from the water supply.
Pre-Mitigation Monitoring
A continuous radon monitor was placed in the crawl space prior to installation of the
2.11-1
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sub-membrane depressurization system. Unfortunately, equipment malfunctions resulted in the loss
of these data. For pre-mitigation data, the radon concentrations were obtained using the alpha-track
detectors mentioned in the Description subsection.
Mitigation System Installation
The Phase 1 sub-membrane depressurization system was installed in early December 1987.
A layer of drainage mat (Enkadrain) was placed on the exposed bedrock. Next, a layer of
polyethylene film was placed over the drainage mat. The seams of the film were sealed with copious
amounts of caulk. Wooden furring strips were used to secure the edges of the film to the concrete
block walls and slab. In this way, a fairly airtight membrane enclosed the exposed bedrock. In all,
three separate rock outcroppings were treated in this manner. PVC piping was used to manifold the
three sub-membrane areas together. An in-line centrifugal blower was used to provide active
depressurization under the membrane.
The Phase 2 wall depressurization system was connected to the sub-membrane system in early
March. This was accomplished in much the same manner as the sub-slab/wall depressurization
systems installed in other homes in this study. The tops of the concrete blocks were filled with foam
insulation. All wall penetrations were sealed.
The Phase 3 water aeration system was installed on April 14, 1987. The aeration unit was
placed downstream from an existing water softener.
Short-Term Results
A continuous radon monitor was placed in the crawl space after installation of the Phase 1
system. Radon concentrations during that monitoring period beginning January 15 and ending
January 26, 1988 averaged 44.2 pCi/L. Alpha-track detectors placed on the first floor from January
15 to March 12,1988 disclosed an average concentration of 11.8 pCi/L. A continuous radon monitor
measuring crawl space concentrations after the installation of the Phase 2 system recorded average
concentrations of 8.5 pCi/L from March 9 to April 10, 1988. A continuous monitor placed on the
first floor after the installation of the Phase 3 system disclosed average radon concentrations of 1.0
pCi/L for a period of approximately 16 days. The reason the CRM was placed on the first floor,
rather than in the crawl space as with all of the other phases, was that no water was used in the crawl
space and the aeration unit was not expected to affect the crawl space concentrations. In retrospect,
it is possible that leaks in the exhaust of the aeration unit could have been releasing high
2.11-2
-------
concentrations of radon stripped from the water into the crawl space. Subsequent long-term
monitoring has, however, disproved that.
Gamma levels on the first floor were mapped using the survey meter. Readings on the first
floor were found to be below 40 microR/hr.
Follow-Up Monitoring
Long-term measurements indicated average radon concentrations of 11.8 pCi/L in the crawl
space and 1.3 pCi/L on the first floor from April 14, 1988 to March 7, 1989.
Mitigation System Costs
The Phase 1 installation totalled $3,650.73. Of that total, $2,328.00 was for labor costs.
The Phase 2 installation totalled $625.00, of which $500.00 was for labor.
The Phase 3 water aeration system cost $2,750.00, of which $750.00 was for labor.
Discussion
The installation of the sub-membrane depressurization system was very labor intensive.
Sealing the seams and edges of the film to provide a nearly airtight covering required many hours of
hands-and-knees work by the installers.
The installation of the Phase 2 system was much easier to accomplish and required minimal
labor. It is not known which action of Phase 2 reduced the concentrations the most. However, the
wall depressurization system would not have been as effective without the sealing efforts.
2.11-3
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Figure 2.11-1. House Op-05. Comparison od Radon Measurements by Phase.
2.11-4
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2.12 HOUSE OP-06
Description
This single family wood-framed home was built on an exposed sloping lot. The house rests
on an open top, hollow-core, concrete block foundation. The substructure consists of a basement
area used for storage and an open crawl space filled with large rock outcroppings. There were
several floor and wall penetrations.
Combustion appliances in the basement included an oil-fired boiler used to satisfy space
heating and domestic hot water requirements.
Initial screening tests performed in April 1986 revealed average radon concentrations of 26.2
pCi/L in the basement and 7.8 pCi/L on the first floor.
Diagnostic Testing Results/Interpretation
Initial diagnostic testing was performed in November 1986. Grab samples taken from beneath
the floor revealed an average concentration of 820 pCi/L. Wall samples averaged 80 pCi/L. A grab
sample taken in the crawl space disclosed a concentration of 29 pCi/L. Communications testing
indicated good communications beneath the floor slab.
Based on the data gathered during the diagnostic testing, it was decided that the Phase 1
mitigation system would involve isolating the crawl space from the basement area. Phase 2 would
attempt to decrease negative pressures in the basement by supplying the boiler with outside
combustion air. Phase 3 would involve the installation of a sub-slab depressurization system. Phase
4 would combine a wall depressurization tap with the sub-slab system.
Pre-Mitigation Monitoring
A continuous radon monitor was placed in the basement to gather pre-mitigation radon
concentrations. On the day after the CRM was placed, the homeowners informed the project
manager that they did not wish to have any mitigation work performed. This decision was based upon
a conversation with a local government health representative. In that conversation, the local
representative told the homeowners that the first floor levels were not "that high" and that no
mitigation work should be performed. The homeowners did, however, agree to allow additional
testing in the home.
2.12-1
-------
Mitigation System Installation
No mitigation work was performed at this home.
Short-Term Results
All data gathered will be discussed in the following section.
Follow-Up Monitoring
A series of long-term measurements were made using alpha-track detectors. Radon
concentrations from February 9,1988 to March 7,1989 averaged 16.9 pCi/L in the basement and 4.5
on the first floor. All measurements made at this home are shown on Figure 2.12-1.
Mitigation System Costs
No mitigation systems were installed in this home.
Discussion
Long-term measurements averaged 16.9 pCi/L in the basement and 4.5 pCi/L on the first
floor. These radon concentrations, while relatively low, exceed the 4 pCi/L guideline. Although this
is a guideline only, and not a standard, the Real Estate industry has adapted that guideline to be a
de facto standard, and many are requiring measurements prior to listing homes for sale.
2.12-2
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2.12-3
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2.13 HOUSE OP-09
Description
This two story wood-framed home was built in 1938 on a level lot in a subdivision. The home
rests on a poured concrete foundation with a poured concrete floor slab. The floor slab is
approximately six feet below-grade. There are no designed floor penetrations.
Initial screening tests performed in late August 1986 revealed average radon concentrations
of 20.7 pCi/L in the basement.
Diagnostic Testing Results/Interpretation
Initial diagnostic testing was performed in November 1986. Grab samples taken beneath the
concrete slab averaged 820 pCi/L. Inspection of the walls revealed layers of large aggregate,
therefore, it is suspected that the concrete was mixed by hand. This poor mix of concrete resulted
in very porous walls which allowed the easy passage of gas.
Based upon the data gathered during the diagnostic testing, it was decided that the Phase 1
mitigation technique would involve the sealing of the poured concrete walls. Phase 2 would involve
the installation of a sub-slab depressurization system using a regenerative blower to provide active
depressurization.
Mitigation System Installation
The Phase 1 mitigation system installation began on January 20, and was completed on
January 21, 1987. The basement walls were washed to remove dust and debris. All large holes were
filled with mortar or other appropriate sealants. A single coating of fiberglass-impregnated bonding
cement was applied to the entire inside of the foundation walls.
The Phase 2 sub-slab depressurization system using a regenerative blower was installed on
February 18,1987. Four 3/4" penetrations were made along the perimeter of the floor slab. The four
penetration points were manifolded together and connected to the regenerative blower. PVC piping
was used to exhaust the soil gases to the outside.
Short-Term Results
A continuous radon monitor placed in the basement during the mitigation installation revealed
that radon concentrations slowly decreased to an average of 14.7 pCi/L for a period of approximately
seven days after the Phase 1 efforts.
2.13-1
-------
Radon concentrations after the Phase 2 installation rapidly fell to an average of 3.4 pCi/L for
a period of seven days after the installation was completed and activated.
Follow-Up Monitoring
Long-term radon concentrations obtained with the use of alpha-track detectors averaged 1.0
pCi/L in the basement, 0.5 pCi/L on the first floor and 0.5 pCi/L on the second floor from January
15, 1988 to March 7, 1989.
Mitigation System Costs
The total cost for the installation of the Phase 1 system was $903.00. Of that total, $750.00
was for labor and $153.00 was for materials.
The total cost for the Phase 2 installation was $949.75, of which $500.00 was for labor.
Discussion
The pargeting of the interior foundation walls resulted in a surprising reduction in radon
levels. However, this was not sufficient to lower the concentrations below 4 pCi/L.
The addition of the sub-slab depressurization system maintained radon concentrations well
below the 4 pCi/L level. This is the first known installation of a regenerative blower.
2.13-2
-------
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Figure 2.13-1. House OP-09. Comparison of Radon Measurements by Phase.
2.13-3
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2.14 HOUSE OP-13
Description
This single family modular home was constructed in 1974 on a sloping lot. The home rests
on open topped hollow-core concrete block walls with a 950 sq.ft. concrete floor slab. Three sides
of the home are at or slightly below-grade, the fourth side is earth-bermed to a depth of
approximately six feet. The basement area consists of an attached garage and several partially
finished rooms. Designed slab penetrations include a sump and floor drain.
Initial screening tests performed in August 1986 revealed an average radon concentration of
25.0 pCi/L in the basement. Additional tests performed with alpha-track detectors in December and
January revealed an average concentration of 16.3 pCi/L in the basement and 11.5 pCi/L on the first
floor.
•Diagnostic Testing Results/Interpretation
Initial diagnostic testing was performed in November 1986. Radon grab samples taken from
the floor drain indicated a radon concentration of 183 pCi/L. Grab samples in the wall averaged 27
pCi/L. Communications testing revealed good communications beneath the floor slab, marginal
communications from beneath the slab to the foundation walls, and marginal communications within
the foundation walls. It was suspected that wall communications would be improved if the tops of
the concrete blocks were sealed. An exterior footing drain was found to run around the entire
perimeter of the home and drain to daylight.
Due to the accessibility of the footing drain ends, it was decided that the Phase 1 installation
would consist of a footing drain depressurization system. Phase 2 would involve the installation of
a sub-slab depressurization system using a centrifugal fan for active depressurization.
Pre-Mitigation Monitoring
A continuous radon monitor was placed in the basement nine days prior to the installation
of the Phase 1 exterior footing drain depressurization system. Radon concentrations averaged 13.9
pCi/L during that time.
Mitigation System Installation
An in-line centrifugal fan was connected to one end of the exterior footing drain. One-way
flou reversal valves were installed on each end of the drain to seal the drain from the outside air
2.14-1
-------
except at those times when water was present in the drainage pipe. In that way, a negative pressure
was induced on the entire length of the drain pipe. All accessible block tops, floor and wall
penetrations were sealed.
The Phase 2 system consisted of a sub-slab depressurization system located in the garage area.
An in-line centrifugal fan (Kanalflakt K4) was used to provide active depressurization. The Phase
1 system was deactivated.
Short-Term Results
Immediately after the activation of the Phase 1 system, basement radon concentrations began
to fall and averaged 2.9 pCi/L for a period of approximately nine days. After the Phase 2 system was
installed and activated, radon concentrations averaged 9.1 pCi/L.
Follow-Up Monitoring
Long-term monitoring using alpha-track detectors revealed average radon concentrations from
March 18, 1988 to March 7, 1989 of 6.2 pCi/L in the basement, and 2.1 pCi/L on the first floor, with
the Phase 1 system operating. Conversations with the homeowners revealed that during one
monitoring period included in the preceding averages, the fan system had been deactivated for an
extended period. Concentrations during the period when the fan was off averaged 12.8 pCi/L in the
basement and 3.6 on the first floor.
Mitigation System Costs
The total cost of the Phase 1 system was $677.94, of which $500.00 was for labor.
The total cost of the Phase 2 system was $736.70, of which $500.00 was for labor.
Discussion
The Phase 1 system resulted in a much greater radon reduction than the Phase 2 system. This
was because the footing drain helped to extend the negative pressure field around the entire
perimeter of the home.
2.14-2
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Figure 2.14-1. House OP-13. Comparison of Radon Measurements by Phase.
2.14-2
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2-15 HOUSE OP-16
Description
This single family wood-framed raised ranch was constructed in 1967 on a sloping lot. The
house rests on open-top hollow-core concrete block foundation walls with a poured concrete floor
slab. The home is earth bermed on three sides. The fourth side is at grade. The lower level area
consists of a family room, bathroom, and attached two-stall garage. The entire lower level floor (with
the exception of the garage area) is covered with linoleum. Designed penetrations include a sanitary
clean-out pit in a family room closet.
Initial screening tests performed in October 1986 revealed an average lower level radon
concentration of 32.7 pCi/L. Additional longer-term tests made during December 1986 and January
1987 revealed average concentrations of 25.6 pCi/L on the lower level and 7.6 pCi/L on the upper
level.
Diagnostic Testing Results/Interpretation
Initial diagnostic testing was performed during November 1986. Radon grab samples taken
from beneath the floor slab revealed average concentrations of 46 pCi/L. Grab samples taken from
the interior of the foundation walls averaged 574 pCi/L. Communications testing revealed good
sub-slab to wall communications.
Based on the diagnostic test results, it was decided that Phase 1 would consist of sealing the
tops of the accessible concrete blocks and passively ventilating the foundation walls. The sanitary
clean-out pit would also be covered during Phase 1. Phase 2 would require removal of the passive
vents and installation of an active wall ventilation system. Phase 3 would involve the installation of
a multi-point sub-slab depressurization system, if necessary.
?re-Mitigation Monitoring
A continuous radon monitor was placed on the lower level of the home six days prior to the
installation of the Phase 1 mitigation system. Radon concentrations averaged 55.4 pCi/L during that
period.
Mitigation System Installation
The Phase 1 system was installed on February 19, 1987. The tops of all accessible concrete
blocks were filled with mortar. The sanitary clean-out pit was fitted with an airtight cover. Passive
2.15-1
-------
vents one-and-one-quarter inches in diameter were installed on the exterior foundation wall
approximately every four feet.
The Phase 2 system was installed on March 17,1987. The passive vents installed during Phase
1 were removed and the holes in the foundation walls sealed. A penetration point for the active wall
depressurization system was made in the back wall of the home in the garage. Active ventilation was
provided by a centrifugal fan.
Phase 3 was not installed in this home.
Short-Term Results
A continuous radon monitor was placed on the lower level during the Phase 1 mitigation
system installation. Radon concentrations averaged 40.1 pCi/L for a period of 16 days after the
installation was completed.
A continuous radon monitor revealed an average concentration of 22.7 pCi/L with the Phase
2 system operating. System diagnostics revealed that the pressure field was not extending across the
entire back wall because the tops of the concrete blocks were not adequately sealed. Additional
sealing of the tops of the blocks was performed during July 1987. This was accomplished by drilling
holes in the back wall on the outside of the top blocks and filling this top course of concrete blocks
with a two-part polyurethane foam. Radon concentrations after the foaming were found to be 2.3
pCi/L for a period of six days.
Follow-Up Monitoring
The home was sold in the fall 1987 and the new homeowners elected not to participate in the
project; therefore, no follow-up testing was performed.
Mitigation System Costs
The total cost for the phase 1 installation was $707.58, of which $207.58 was for material.
Phase 2 costs totalled $1,663.00, of which $1,188.00 was for labor.
Discussion
The Phase 1 system resulted in an appreciable decrease in radon concentrations. However,
the annual average concentration would not have been below the 4 pCi/L guideline.
The Phase 2 system did not reach the 4 pCi/L level, mainly due to the open tops of the
2.15-2
-------
concrete blocks. Extraordinary measures were taken to fill the blocks in the summer 1987. Because
the blocks were inaccessible from the interior of the home, holes were drilled into each core of each
block, from the outside of the home. The core was then filled with foam insulation. Although
long-term radon concentrations are not available, pressure differential measurements confirmed a
strong pressure field was being produced in the back wall.
2.15-3
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Figure 2.15-1. House OP-16. Comparison of Radon Measurements by Phase.
2.15-4
-------
2.16 HOUSE OP-17
Description
This single family raised ranch home was built on a sharply sloping lot in 1965. The home
rests on a foundation constructed of hollow-core concrete blocks. A portion of the block tops were
capped. The poured concrete floor slab was covered in most places with tile or carpet. Designed
penetrations include a sanitary clean-out pit and a floor drain. An exterior footing drain extends
around the perimeter of the house.
Initial screening tests performed in October 1986 revealed an average concentration of 49.3
pCi/L in the basement. Additional testing performed in December 1986 and January 1987 revealed
average concentrations of 23.7 pCi/L in the basement and 12.2 pCi/L on the first floor.
Diagnostic Testing Results/Interpretation
Initial diagnostic testing was performed in November 1986. Radon grab samples taken from
the sanitary pit averaged 659 pCi/L. Samples taken from the foundation walls averaged 5 pCi/L.
Communications testing revealed good sub-slab communications.
Based on the diagnostic findings, it was decided that Phase 1 would involve sealing floor
penetrations and the tops of the concrete blocks. A passive sub-slab depressurization system would
be installed during Phase 1. Phase 2 would convert the passive depressurization system into an active
system.
Pre-Mitigation Monitoring
A continuous radon monitor was placed on the lower level ten days prior to the installation
of the Phase 1 system. Radon concentrations averaged 37.1 pCi/L during that period.
Mitigation System Installation
The Phase 1 system was installed in late February 1987. The open tops of accessible blocks
were sealed with mortar. An airtight cover was constructed for the sanitary clean-out pit. A passive
depressurization system was installed in the garage and routed up to the roof through a closet on the
first floor.
The Phase 2 system was installed in early March. A centrifugal fan was placed in the existing
Phase 1 piping to provide active ventilation.
2.16-1
-------
Short-Term Results
With the passive system in place, radon concentrations in the basement averaged 39.3 PCi/L
for a short period of one day. Unfortunately, equipment malfunctions resulted in the loss of
additional data.
The Phase 2 depressurization system averaged 16.3 pCi/L for a period of two weeks after
installation. System diagnostics revealed that the pressure field developed by the system was not
consistent with what was expected. An investigation of the sub-slab aggregate at the penetration
point revealed several large rocks blocking extension of the pressure field. When the rocks were
removed, the pressure field was extended much farther across the floor slab.
Follow-Up Monitoring
Alpha-track detectors placed in the home from March 3, 1988 to March 7, 1989 revealed
average concentrations of 6.5 pCi/1 on the lower level and 4.2 pCi/L on the first floor.
Mitigation System Costs
The Phase 1 costs, which included installing a system to passively depressurize the sub-slab
including sealing the sanitary pit and other openings, totalled $1,629.53, of which $1,500.00 was for
labor and $129.53 was for material.
The Phase 2 costs, which included the addition of equipment to actively depressurize the sub-
slab, totalled $636.00, of which $500.00 was for labor and $136.00 was for material.
Discussion
The increase in radon concentrations during the Phase 1 post-mitigation monitoring should
not be attributed to the mitigation system. That increase is most likely due to the natural variation
in radon concentrations.
The Phase 2 system, while not maintaining levels below 4 pCi/L, was operating very well.
Other radon sources not affected by the depressurization system were causing the radon levels to
exceed 4 pCi/L in this home.
2.16-2
-------
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Figure 2.16-1. House OP-17. Comparison of Radon Measurements by Phase.
116-3
-------
2.17 CONCLUSIONS
The mitigation systems demonstrated in Task I, Subtask 1, Demonstrating Radon Reduction
Techniques in Existing Homes, consist of four types:
* Sub-slab depressurization
* Sealing of radon entry points
* Basement pressurization
* Water treatment
Sub-Slab Depressurization Systems
Sub-slab depressurization systems installed during this phase of the project demonstrated the
best capability of reducing indoor radon concentrations. However, it was clearly seen that installing
a sub-slab depressurization system requires more than penetrating the floor slab with a PVC pipe and
exhausting the soil gas outside of the home. Even with thorough diagnostic testing, many of the
systems required some additional work to reach acceptable radon levels. For example, in House
AR-04, where communications testing indicated sub-slab aggregate with good airflow characteristics,
the initial depressurization system failed to lower the radon concentrations to an acceptable level.
Investigation of the system revealed that the penetration point was placed in an area where numerous
rocks were limiting the pressure field. When the penetration point was moved to a different area
of the basement, the pressure field extended beneath most of the floor slab. Also of interest is the
lesson learned at House OP-17, where the pressure field did not extend very far away from the
penetration point initially. Removing some of the sub-slab aggregate at the penetration point greatly
increased the extent of the pressure field. This has now been accepted as a standard procedure for
tne installation of sub-slab depressurization systems.
Removal of water formed from condensation of moist air within the exhaust pipe in a sub-slab
depressurization was first accomplished by using a condensate drain pump. Although this method
works, it is an additional expense of approximately $75 $100 and another component that can fail
over time. Midway through this project, it was decided that instead of installing condensate pumps,
the system would be redesigned to enable any condensation to run down the pipe into the sub-slab
aggregate. There seemed to be no disadvantage to using this technique instead of the condensate
pumps.
Using a regenerative blower in House OP-09 demonstrated that sub-slab depressurization
2.17-1
-------
systems can work in homes where the sub-slab aggregate is very resistant to airflow. The cost of a
regenerative blower is high, approximately three to four times the cost of a centrifugal blower.
However, if a sub-slab depressurization system is necessary to reduce the radon levels, then the extra
cost required to insure that the system will work seems acceptable.
Sealing of Radon Entry Points
Sealing of radon entry points was demonstrated in many of the houses in this study. Results
of sealing as a stand-alone mitigation technique were varied. For example, the sealing of the sanitary
clean-out pits in two homes had little, if any, effect on the indoor radon concentrations. In addition,
while sealing cracks and holes and pargeting the interior of the foundation walls in House OP-09 did
result in a nearly 50% decrease in radon levels, the decrease did not reduce the radon levels below
4 pCi/L.
Based upon these demonstrations, it is suggested that sealing alone should not be considered
a reliable mitigation technique. If, however, the initial radon concentrations are low enough (less
than 20 pCi/L) to allow for experimentation, sealing by the homeowner could be tried.
It is obvious that sealing floor and wall cracks can have a beneficial impact on the
effectiveness of a depressurization system. For example, the wall depressurization systems installed
in Houses OP-01 and OP-16 did not have a great effect on the radon levels until the wall cracks and
open tops of the hollow-core concrete blocks were sealed. Although not proven, it is suspected that
if the large floor cracks in House AR-19 had been sealed, the sub-slab depressurization system would
have been effective in reducing the radon concentrations.
Basement Pressurization
This technique was demonstrated in two homes with totally different levels of success. The
owners of House AR-09 strongly objected to the system and would not allow it to be tested. The
owners of House AR-17 did not object to the pressurization system. From this home, results are very
favorable. Radon concentrations were maintained at a level of less than 4 pCi/L for almost a year.
It is not clear why the owners of one home objected so strongly to the system while the other
homeowners accepted the system. Both systems were unobtrusive and neither was inordinately loud.
It is clear that additional considerations must be made when designing and installing a pressurization
system. Of particular concern is the installation of a device that will turn the system off in the event
of a fire. In this project, smoke alarms equipped with normally closed relays were wired into the fan
2.17-2
-------
system. Thus, if the smoke alarm were activated, the relay would open and the fan would turn off.
Another concern is the ease of defeating the system. For example, if a basement door or
window is left open, the basement will not be pressurized and radon concentrations will increase.
Provisions can be made to lessen this problem, such as making the basement windows inoperable and
providing automatic door closers. These provisions can also be defeated, though, so the best way to
ensure that the system continues to function is by educating the occupants.
Water Treatment
The water supply was found to be a major source of indoor radon in two homes. Two types
of water treatment devices were demonstrated. One type, an activated charcoal filter, adsorbs the
radon. The other type, a water aeration system, aerates the water and causes the radon to outgas.
While both systems performed well, when the water originally contained very high radon levels, it was
found that the activated charcoal filter quickly became a source of gamma radiation from the decay
of the adsorbed radon. Since this was considered unacceptable by the project sponsors and managers,
plans were made to remove the filter. The homeowner, however, expressed satisfaction with the taste
of the treated water and requested that the activated charcoal filter be left in place. It was,
therefore, decided that a water aeration unit would be installed before the activated charcoal filter
to remove radon from the water, and the filter would be left in place to help improve the taste of
the water.
The water aeration systems installed performed very well. Radon concentrations were greatly
reduced. Unfortunately, the systems installed during this project occupied a large area in the garage
and crawl space and were extremely noisy. There is also some concern about other pollutants that
are being introduced into the water supply by the aeration system. If a pollutant is present in the
outside air, it is conceivable that it could be introduced into the household water. These concerns,
however, do not present a major problem to the use of a water aeration system to remove radon.
2.17-3
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SECTION 3
ASSESSING PREVIOUSLY INSTALLED MITIGATION TECHNIQUES
IN EXISTING HOUSES
3.0 OVERVIEW
A pioneering infiltration, ventilation, and indoor air quality survey of 60 New York State
houses was conducted in 1982-83. Out of a sample population, 14 homes were discovered with
moderately high indoor radon concentrations. Early in 1984, various low-cost radon mitigation
techniques were installed in these homes, including sealing radon entry points, sub-slab
depressurization, isolating and ventilating unpaved crawl spaces, and heat recovery ventilation. These
mitigation systems represent some of the earliest installed in the United States, using low cost,
common residential construction methods and materials. A full report on these early radon mitigation
efforts can be found in NYSERDA Report # 85-10.
These homes were visited during this project to inspect the systems and assess their long-term
effectiveness. A house-by-house description of these activities is presented in this section.
Sample House Description
The purpose of the original project was to investigate the effects infiltration and ventilation
had on energy use and indoor air quality in a wide variety of home styles across New York State.
Among other parameters, these homes varied by age, style, location, and the type of combustion
appliances. The oldest home was more than 100 years old. The newest was less than one year old
at the time of the original project. The homes ranged from leaky village Victorians close to Lake
Ontario, to nearly airtight underground homes on the New York-Vermont border. Combustion
appliances included modern furnaces and boilers, circa 1930 coal furnaces converted to burn oil or
natural gas, and unvented kerosene space heaters as primary heat sources. This original sample of
60 homes represented a good cross-section of homes across New York State. The 14 homes
containing elevated radon levels were discovered using the ATD sampling method. Samplers were
placed in the homes in 1982. At most homes, these were left in place for at least one month. At
many of the homes, additional tests were performed prior to the installation of the mitigation
techniques. The average concentrations found during this initial pre-mitigation period, or Phase 1A,
are reported in the following house-by-house discussions.
3.0-1
-------
In an attempt to compare pre-mitigation to post-mitigation, and floor-to-floor concentrations,
only those time periods when concurrent tests were made on multiple floor levels are included in the
analysis. A listing of all measurements made at the homes is found in Appendix B.
Initial Radon Mitigation Techniques
During the original study, a wide variety of mitigation techniques was employed in an effort
to reduce the indoor radon concentrations. In many of the homes, sub-slab depressurization systems
were installed. Numerous types of caulks and sealants were used. Commercially available and
sight-built heat recovery ventilators were installed.
Post-mitigation, or Phase IB of this study, radon concentration data for these homes were also
obtained using the alpha-track detector method and are presented in this section using the same
criteria as described above.
Follow-Up Observations
The follow-up visits attempted to determine the effectiveness of the systems installed during
the first study. During the visit to each house, an inspection was made to assess the system and
system components. Visual inspections noted damage that would lessen the effectiveness of the
system. An assessment was also made of the homeowners' satisfaction with their system. In most
homes, detailed diagnostic tests were also performed to help assess the long-term effectiveness of the
systems. Routinely, sub-slab communications tests, airflow measurements, sub-slab to basement
pressure differences, and other measurements were made where applicable. Short-term radon
measurements were performed using the activated charcoal method. These short-term measurements
are reported in this section as follow-up, or Phase 2A, measurements.
Modified Radon Mitigation Techniques
Mitigation systems and components that were not maintaining radon concentrations below
4 pCi/L were replaced, updated, or redesigned. After the original mitigation systems were
investigated and repairs or modifications made (if any), long term radon measurements were
performed using alpha-track detectors. These data are presented in this section as modified or Phase
2B measurements, and conform to the same parameters as previously mentioned.
3.0-2
-------
Results
The data described in the above subsections are presented in graphical form for each home.
In addition, many homes had measurements whose results are not considered in the figures. In most
cases, these data will be slightly different than data presented on the figures. This is because of the
selection criteria used for the data concentrations, including only those measurements that could be
used to compare the floor-to-floor radon concentrations. These additional data are of interest
primarily because of the long monitoring periods that the measurements encompass.
3.0-3
-------
3.1 HOUSE NM-02
Description
This single-family, wood-frame house has a full basement with an all-weather, wood
foundation and a poured concrete floor slab. Floor penetrations include several floor drains and a
floor/wall joint crack. Sub-slab aggregate consists of crushed stone. Initial radon measurements made
prior to the start of any mitigation efforts averaged 6.9 pCi/L in the basement and 8.1 pCi/L on the
first floor during two monitoring periods from June 25, 1982 to November 15, 1983.
Initial Radon Mitigation Techniques
During the previous project, a sub-slab depressurization system was installed in a basement
utility room. Four-inch PVC piping was connected to an unused furnace flue to exhaust the soil
gases above the roof of the home. A 20-watt axial fan (Dayton #4C550) actively powered the system.
This fan was placed in the basement utility room. The drains and perimeter cracks were sealed where
possible with polyurethane caulk. This system reduced the indoor radon concentrations to 3.5 pCi/L
in the basement and 3.6 pCi/L on the first floor during the monitoring period from March 27 to April
27, 1984.
Follow-Up Observations
Pressure differential measurements disclosed that the suction pipe to basement pressure
differential was -80 Pa. Tracer gas was injected into the suction pipe to disclose any leaks. A leak
in the piping where the PVC connected to the flue was found. No other leaks were detected. A
visual inspection found the polyurethane caulk to be in good shape. Short-term charcoal canister
measurements revealed average concentrations of 8.5 pCi/L in the basement and 11.2 pCi/L on the
first floor during the period from December 3 to December 6, 1986.
Modified Radon Mitigation System
Although the axial fan was running smoothly, the fan was replaced with an in-line centrifugal
fan (Kanalflakt K4). Polyurethane caulk was used to seal the pipe leak. System diagnostic testing
disclosed no leaks in the piping system and a pressure differential of -250 Pa between the suction
pipe and the basement. With the modified system in place, long-term alpha-track measurements
disclosed a concentration of 1.4 pCi/L in the basement and 1.8 pCi/L on the first floor from October
22, 1987 to March 25, 1988.
3.1-1
-------
Results
Figure 3.1-1 presents the data discussed in the preceding subsections. Analysis of the radon
concentrations and the system data indicates that the initial Phase 1A concentrations were reduced
to a level below the 4 pCi/L target by the original mitigation system. Leaks discovered in the exhaust
pipes during the follow-up visit may have accounted for the increase in radon concentrations during
the Phase 2A testing period. Another possible explanation for the increase in concentrations may
be the long-term temporal variations in radon levels that short-term measurements do not measure.
Phase 2B measurements indicate that the modified radon mitigation system maintained an average
concentration well below the 4 pCi/L level. A comparison of the effectiveness of the original system
versus the modified system should not be attempted with this data, however, because the monitoring
periods during the two phases encompass different lengths of time during different seasons of the
year.
3.1-2
-------
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PHASE 1B
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TEST PHASE
MONITORING TYPE
PHASE 2B
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Figure 3.1-1. House NM-02. Comparison of Radon Measurements by Phase.
3.1-2
-------
3.2 HOUSE NM-05
Description
The substructure of this single family home consists of a small walk-in basement with a poured
concrete floor slab, an adjoining accessible crawl space with a concrete floor slab, and an inaccessible
crawl space with a fractured limestone bedrock floor covered with sand and a polyethylene film.
Basement and crawl space walls are hollow-core concrete blocks with a solid top course of blocks.
Basement floor penetrations included a 2.25 square foot sump opening and a floor/wall joint crack.
Initial radon measurements made from July 12, 1982 to December 23, 1982, averaged 16.6 pCi/L in
the basement, 7.6 pCi/L on the first floor, and 5.3 pCi/L on the second floor. A second monitoring
period, from August 24 to November 15, 1983, revealed average concentrations of 16.2 pCi/L in the
basement, 8.6 pCi/L on the first floor, and 8.4 pCi/L on the second floor.
Initial Radon Mitigation Techniques
A sump depressurization system was installed in the basement of this home. The sump hole
was provided with an airtight cover constructed of plywood. Active depressurization was provided
by a 20-watt axial computer type fan (Dayton #4C550). All accessible floor and wall cracks were
sealed using butyl caulk or closed-cell expanding polyurethane foam.
The inaccessible crawl space was actively vented with a second axial fan identical to the one
described above. Post-mitigation alpha-track measurements disclosed radon concentrations of 3.0,
1.8, and 1.6 pCi/L in the basement, first, and second floors, respectively, from March 9,1984 to May
1, 1984.
Follow-Up Observations
An inspection of the sump depressurization system in the basement revealed that the plywood
cover capping the sump hole was damp, soft, and discolored. The butyl caulk sealing the plywood
cover to the floor had deteriorated to the point where leaks had developed. Positive pressure leaks
to the basement were discovered in the fan housing. The pressure differential between the suction
pipe and the basement was -1 Pa. No airflow could be measured at the exhaust. Investigation
revealed that water had collected in a water trap that had been placed in the exhaust pipe. This
water had completely blocked airflow. Closer examination revealed that the small diameter hose that
was connected to the trap for drainage purposes had become blocked with debris. All water was
drained from the exhaust pipe, and the pressure differential between the suction pipe and basement
3.2-1
-------
was measured with a magnehelic. This measurement revealed a pressure differential of 60 Pa. The
fan ventilating the crawl space was operating well with no apparent problems. Short-term Phase 2A
charcoal canisters, placed approximately 24 hours after the water was drained from the system,
revealed radon concentrations of 23.0 pCi/L in the basement and 14.3 pCi/L on the first floor.
Modified Radon Mitigation Techniques
The sump depressurization system was redesigned with no low points that would allow
condensation to block the exhaust pipe. The plywood cover for the sump hole was replaced with one
made of treated plywood. All accessible holes and cracks in the floor and walls were sealed with
polyurethane caulk. Additionally, a soil depressurization system was installed in the inaccessible crawl
space by drilling a hole through the foundation wall to reach the soil beneath the crawl space area.
A PVC pipe was then connected to the existing sump depressurization suction pipe. In this way,
one 40-watt in-line fan (Kanalflakt K6) served to actively depressurize both areas. Differential
pressure measurements revealed a pressure of -100 Pa in the suction pipe relative to the basement
air pressure. Phase 2B radon measurements made with the alpha-track detector method revealed an
average concentration of 3.4 pCi/L in the basement, 2.3 pCi/L on the first floor and 1.9 pCi/L on the
second floor from October 21, 1987 to March 28, 1989.
Results
Figure 3.2-1 presents the data discussed in the above subsections. Comparison of the Phase
1A and IB radon concentrations indicate that the original system succeeded in reducing indoor radon
levels. As in all radon measurements, however, different measurement lengths, temporal variations,
and other parameters that effect the indoor radon concentration may be accountable for some, if not
all, of the reduction. Considering the amount the concentrations were decreased, however, it can be
stated with some confidence that the original system did decrease the concentrations to some extent.
The relatively high Phase 2A measurements are most likely due to the leaks in the sub-slab exhaust
piping. These leaks, that were on the positive pressure side of the exhaust fan, were allowing
concentrations of radon to be drawn from beneath the slab and exhausted into the basement at a rate
much higher than natural driving forces would provide. The Phase 2B concentrations indicate that
the modified system is maintaining a long-term concentration comparable to the levels maintained
by the original system.
3.2-2
-------
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SFCOND Fl OOR
PHASE 1A
ATD
PHASE 1B PHASE2A
ATD GAC
TEST PHASE
MONITORING TYPE
PHASE 2B
ATD
Rgure 3.2-1. House NM-05. Comparison of Radon Measurements by Phase.
3.2-3
-------
3.3 HOUSE NM-12
Description
This single-family colonial home was built in 1984. The substructure consists of a combination
basement and crawl space. Foundation walls and basement floor slab are of poured concrete. The
crawl space floor is crushed stone. Basement floor penetrations include a sump connected to interior
footing drains, a French drain, and minor floor cracks. The sub-slab aggregate consists of crushed
stone. Initial radon measurements made using alpha-track detectors revealed radon concentrations
averaging 18.3 pCi/L in the basement, 5.4 on the first floor, and 12.9 pCi/L on the second floor from
September 18 to November 19, 1983.
Initial Radon Mitigation Techniques
The French drain was sealed with closed-cell polyurethane foam. Accessible floor and wall
penetrations were sealed with polyurethane caulk. The sump hole was fitted with an airtight cover
of treated plywood. A sump depressurization system using a 20-watt axial fan (Dayton #4C550) for
active depressurization was installed. The crawl space was passively ventilated with three vents. In
addition, the crawl space ceiling and air handling ducts were insulated and a tight-fitting crawl space
door installed. After the installation and activation of the initial mitigation system, radon
concentrations were found to be 2.9 pCi/L in the basement, 0.8 pCi/L on the first floor, and 1.4 pCi/L
on the second floor from March 9 to April 26, 1984.
Follow-Up Observations
The follow-up visit to this house revealed that a large crack had developed in the basement
floor slab. Whether this crack was produced by the settling of the house, improper construction, or
was the effect of the depressurization system could not be determined. The closed-cell polyurethane
foam used to seal the French drain was in good condition, as was the polyurethane caulk used to seal
the floor and wall penetrations. The treated plywood sump cover was also in good condition. There
were no discernible leaks around the crawl space door or in the exhaust pipe. Pressure differential
measurements revealed an air pressure of -14 Pa. in the suction pipe as compared to the basement
air pressure. Smoke sticks revealed that basement air was being drawn through the floor crack by
the depressurization system. Short-term charcoal measurements disclosed radon concentrations of
4.7 pCi/L in the basement and 2.4 pCi/L on the first floor. Soon after the first follow-up visit, the
home was sold. The new homeowners were fully informed by the original owners about the radon
3.3-1
-------
mitigation system. Both the original owners and the new owners expressed satisfaction with the
original system.
Modified Radon Mitigation Techniques
Although the original fan was functioning well, it provided a relatively weak negative pressure
field beneath the slab. Also, other fans of this type had failed, so it was decided to replace the
original fan with a 20-watt in-line centrifugal fan (Kanalflakt K4) designed for use in depressurization
systems. In addition, floor cracks were sealed with no-shrink grout with a plastic binder (Acryl 60).
The combination of sealing the cracks and replacing the fan increased the pressure differential
between the suction pipe and the basement to -80 Pa. With the modified mitigation techniques in
place, radon concentrations averaged 2.3 pCi/L in the basement, 1.5 pCi/L on the first floor, and 1.4
pCi/L on the second floor during the monitoring period from July 5, 1988, to March 21, 1989.
Results
Figure 3.3-1 illustrates the radon concentrations discussed in the above subsections. As
shown, the original radon mitigation technique reduced radon concentrations to a level below the 4
pCi/L target. Phase 2A follow-up testing indicated radon concentrations slightly higher than the
Phase IB measurements, however, the natural variations in indoor radon concentrations and the
inherent accuracy and precision of the measurements themselves make this difference insignificant.
Radon concentrations after the mitigation system was modified compare favorably with the Phase IB
averages, but once again, the difference in concentrations is insignificant. What is significant,
however, is that the additional long-term measurements averaged 2.5 pCi/L in the basement over the
nearly one and one-half year monitoring period. The comparison of the additional measurements
with the Phase 2B basement averages indicates that the modified radon mitigation system is
maintaining a fairly steady concentration in the basement.
Of interest is that the radon concentrations on the second floor were much higher than the
first floor concentrations during the initial Phase 1A measurements, but nearly identical to each other
in subsequent tests. It is suspected, but not confirmed, that a leaky supply heating duct running
through the crawl space was drawing radon from the crawl space and depositing it on the upper floor.
This occurs because supply ducts may be under negative air pressure in relation to the surrounding
air pressure when the heating system is not running. When the original mitigation system was
installed, the ducts running through the crawl space were taped and insulated, cutting off that source
of radon from the upper floors.
3.3-2
-------
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2ND FLOOR
PHASIE 1A
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PHASE 1B
AID
PHASE 2A
GAG
PHASE 2B
AID
TEST PHASE
MONITORING TYPE
Figure 3.3-1. House NM-1Z Comparison of Radon Measurements by Phase.
3.3-3
-------
3.4 HOUSE NM-16
Description
This single-family, wood-frame home rests on a slab-on-grade foundation. The only floor
penetration discovered was a floor drain in the laundry room. Initial radon concentrations were
found to average 1.5 on the first floor and 1.6 pCi/L on the second floor during two periods starting
on March 3, 1983 and ending November 9, 1983.
Initial Radon Mitigation Techniques
Conversations with the homeowner indicated that an existing heat recovery ventilator was
rarely used. A timer was installed on the heat recovery ventilator and set to run the ventilator for
15 minutes every hour. Post-mitigation radon concentrations averaged 2.4 pCi/L on the first floor
and 0.8 pCi/L on the second floor from April 9 to May 2, 1984.
Follow-Up Observations
The heat recovery ventilator was inspected during the follow-up visit. There was no visual
degradation of the system and the timer controls were still set on the original setting of on 15
minutes/off 45 minutes. Short-term activated charcoal measurements made from March 25 to March
28, 1988 revealed average concentrations of 2.3 pCi/L on both floors in the home.
Modified Radon Mitigation Techniques
No modifications were made to the original system in this home. Long-term alpha-track
measurements averaged 2.1 pCi/L on both floors from March 25, 1988 to March 11, 1989.
Results
Based on the comparison of measurements made during each phase, the heat recovery
ventilator is having little, if any, impact upon the indoor radon concentrations. This is most likely due
to the small additional amount of ventilation that the HRV is delivering. Increasing the volume of
fresh air would most likely result in lower radon concentrations in this home. However, the
increased cost of energy makes this option too expensive to be considered for the small reduction in
radon this would deliver.
3.4-1
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AID
PHASE 1B
AID
PHASE 2A
GAC
PHASE 2B
AID
TEST PHASE
MONITORING TYPE
Figure 3.4-1. House NM-16. Comparison of Radon Measurements by Phase.
3.4-2
-------
3.5 HOUSE NM-19
Description
This 100-year-old Victorian Colonial home rests on a fieldstone and mortar foundation. The
basement floor is poured concrete. There are significant floor and wall openings. Initial radon
measurements disclosed an average radon concentration of 18.8 pCi/L in the basement and 2.1 pCi/L
on the first floor during the Phase 1A monitoring period, August 12, 1982 to November 1, 1983.
Initial Radon Mitigation Techniques
To reduce radon concentrations, a 150-cfm heat recovery ventilator was installed to ventilate
the basement. The unit was set to run for about 10 minutes per hour. The numerous cracks and
holes in the walls and floor made a low-cost sealant-related solution impractical. Post-mitigation
radon concentrations were found, through the use of alpha-track detectors, to average 12.1 pCi/L in
Ihe basement, 2.5 pCi/L on the first floor, and 3.0 pCi/L on the second floor.
Follow-Up Observations
At the time of the follow-up inspection, the heat recovery ventilator was found to be
operating correctly. A short-term radon measurement using activated charcoal canisters disclosed
Fadon concentrations of 19.3 pCi/L in the basement, 3.8 pCi/L on the first floor, and 3.7 pCi/L on
the second floor.
Modified Radon Mitigation Techniques
No additional work was performed at this home. Long-term monitoring of radon
concentrations using alpha-track detectors revealed average radon concentrations of 10.0 pCi/L in the
basement, 2.8 pCi/L on the first floor, and 2.4 pCi/L on the second floor from November 21, 1988
to March 2, 1989.
Results
As in house NM-16, the heat recovery ventilator is having little, if any, effect on the indoor
radon concentrations in this home. The same reasons probably apply. Long-term measurements
made in the basement for a period of nearly one year disclosed an average concentration of 11.9
pCi/L. The difference between the additional long-term measurements and the Phase 2B
measurements is insignificant.
3.5-1
-------
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PHASE 1A PHASE 1B PHASE 2A PHASE 2B
ATD ATD QAC ATD
TEST PHASE
MONITORING TYPE
Figure 3.5-1. House NM-19. Comparison of Radon Measurements by Phase.
3.5-2
-------
3.6 HOUSE NM-21
Description
The substructure of this single-family, wood-frame colonial home consists of a full basement.
Foundation walls are constructed of open-top hollow-core concrete blocks. The floor slab is poured
concrete with a French drain and sump hole. An interior footing drain is connected to the sump
hole. Initial radon concentrations averaged 49.8 pCi/L in the basement, 15.0 pCi/L on the first floor,
and 12.7 pCi/L on the second floor.
Initial Radon Mitigation Techniques
A sump depressurization system was installed in this home. The sump was capped with a
plywood cover. Active ventilation for this system was provided by a 30-watt axial fan (Dayton
#4C720). Closed-cell polyurethane foam insulation was used to seal the French drain and open block
tops. The interior of the foundation walls was sealed with cement paint. Post-mitigation radon
concentrations averaged 1.4 pCi/L in the basement, 0.9 pCi/L on the first floor, and 0.6 pCi/L on the
second floor from March 12 to April 26, 1984.
Follow-Up Observations
During the first follow-up visit, it was noted that the closed-cell polyurethane foam was in
good condition. The cement paint applied to the interior of the foundation walls was also in good
condition with the exception of small discolored areas that were slightly damp. Pressure differentials
between the suction pipe and basement were found to be -12 Pa., with an exhaust airflow of 120 cfm.
Scraps of wood were found in the exhaust pipe, apparently put there by children. Tracer gas injected
into the system disclosed leaks to the inside of the basement from the positive pressure side of the
fan. Butyl caulk used to seal around the edges of the plywood cover had deteriorated. The plywood
cover itself was found to be in good condition. Short-term measurements using activated charcoal
canisters disclosed radon concentrations of 2.9 pCi/L in the basement and 1.5 pCi/L on the first floor.
Modified Radon Mitigation Techniques
Space limitations did not allow the replacement of the existing axial fan with a larger and
more suitable in-line centrifugal fan, so the existing fan was replaced with an identical model to insure
the longevity of the active depressurization system, especially if a piece of wood might have caused
3.6-1
-------
some damage to the fan that was not visible to the observer. A louvcred screen was placed on the
end of the exhaust pipe to prevent foreign matter from blocking the exhaust. Where possible, the
butyl caulk was removed and replaced with polyurcthane caulk. Pressure differentials between the
suction pipe and the basement air were found to be -45 Pa, with an airflow of 100 cfm. Long-term
radon concentrations averaged 0.8 pCi/L in the basement, and 0.3 pCi/L on the second floor from
October 21, 1987 to March 27, 1989.
Results
Modification of the original system had little or no impact on the average long-term radon
concentrations in the home.
3.6-2
-------
52 -
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PHASE 1 A PHASE 1B PHASE 2A PHASE 2B
AID AID QAC AID
TCST PHASE
MONITORING TYPE
Figure 3.6-1. House NM-21. Comparison of Radon Measurements by Phase
3.6-3
-------
3.7 HOUSE NM-26
Description
This passive solar home has air circulation ducts running through a sand thermal storage mass
located beneath the floor slab. There is a 2.5 m x 2.5 m opening through the middle of. the storage
mass to the natural soil, forming a below-grade room with poured concrete walls and floor. A cooling
pipe runs from a tree-shaded opening in the ground approximately 50 feet from the home to the
below-grade room. The cooling pipe can be connected to the circulation ducts running through the
heat storage. There are several pipe penetrations through the walls and a sump opening in the floor.
The below-grade room was found to be under negative pressure, relative to the outside air pressure,
due to the operation of the fans in the circulation system. In the summer, the fans that circulate
house air through the thermal mass from the cooling pipes are no longer used. The circulation fans
are only rarely used in the winter. Initial radon concentrations averaged 8.6 pCi/L in the below-grade
room, 7.7 pCi/L on the first floor, and 4.5 pCi/L on the second floor during two monitoring periods,
from August 24, 1982 to October 29, 1983.
Initial Radon Mitigation Techniques
The cooling pipe running below-grade was sealed. Pipe penetrations and floor and wall cracks
were sealed with polyurethane caulk. The sump opening was covered with a plywood top. The air
circulation fans were modified to produce a slight positive pressure in the below-grade room as
compared to the outside air pressure. Post-mitigation monitoring disclosed an average radon
concentration of 9.1 pCi/L in the below-grade room, 4.1 pCi/L on the first floor, and 4.2 pCi/L on
the second floor from March 6 to May 5, 1984. These radon concentrations indicate that the initial
mitigation techniques had little, if any, impact on the indoor radon concentrations.
Follow-Up Observations
At the time of the follow-up visit, the circulation fans were not operating. All seals, including
the polyurethane caulking were found to be in good condition. Short-term activated charcoal
measurements disclosed radon concentrations of 1.2 pCi/L on the first floor and 0.5 pCi/L on the
second floor from June 24 to June 27, 1987. Below-grade room radon concentrations are not known.
Modified Radon Mitigation Techniques
No additional work was performed at this home. Long-term radon concentrations averaged
3.7-1
-------
6.1 pCi/L on the first and second floors during the monitoring period, June 24,1987 to June 9, 1988.
Below-grade room radon concentrations are unknown.
Results
As no additional work was performed at this home, the difference between the Phase IB and
Phase 2B averages can be attributed to the natural variations in indoor radon concentrations and the
difference in monitoring duration and time of year.
3.7-2
-------
PHASE 1A
ATD
PHASE 18
PHASE 2A
GAC
TEST PHASE
MONITORING TYPE
PHASE 2B
Figure 3.7-1. House NM-26. Comparison of Radon Measurements by Phase.
3.7-3
-------
3.8 HOUSE NM-28
Description
This wood-frame farmhouse was built in the early 1800s on a rock and mortar foundation.
Significant cracks and openings in the walls and floor were evident. Initial radon measurements made
from August 25, 1982 to April 9, 1983, revealed an average concentration of 9.3 pCi/L in the
basement, 5.9 pCi/L on the first floor, and 3.6 pCi/L on the second floor.
Initial Radon Mitigation Techniques
A 150-cfm heat recovery ventilator (HRV) was installed in this home and set to operate
continuously. Alpha-track detectors deployed from March 29 through April 30,1983 disclosed radon
concentrations averaging 4.8 pCi/L in the basement, 1.4 pCi/L on the first floor, and 1.5 pCi/L on the
second floor.
Follow-Up Observations
During the visit, the HRV was inspected and found to be operating properly. Short-term
activated charcoal measurements indicated an average concentration of 3.6 pCi/L in the basement,
1.6 pCi/L on the first floor, and 1.5 pCi/L on the second floor from June 30 to July 3, 1987.
Modified Radon Mitigation Techniques
No additional work was performed at this home. Long-term monitoring from June 30,1987
to June 7, 1988 revealed average radon concentrations of 4.7 pCi/L in the basement and 2.7 pCi/L
on the first floor. Long-term averages on the second floor from June 30, 1987 to March 21, 1988
were found to be 4.6 pCi/L.
Results
The differences between the Phase IB and Phase 2B average concentrations can be attributed
to the natural variation in radon concentrations. Analysis of the individual measurements indicates
that radon concentrations are at their lowest during the warmer season in this home and increase
during the colder seasons. In fact, the Phase IB measurement compares favorably with the Phase
2B measurement of the same season.
3.8-1
-------
INITIAL
POST-MITIGATION FOLLOW-UP
TESTING PHASE
MODIFED
Figure 3.5-1. House NM-28. Comparison of Radon Measurements by Phase.
3.8-2
-------
3.9 HOUSE NM-29
Description
This passive solar home contains a heat storage mass (sand) with air circulation ducts as in
house NM-26. Initial radon testing using alpha-track detectors was performed from August 26,1982
through April 19,1983. Radon concentrations during this period averaged 7.4 pCi/L in the basement
and 7.6 pCi/L on the first floor. A second monitoring period, again using alpha-track detectors, began
on August 7, 1983 and ended on October 29, 1983. Radon concentrations for this period averaged
0.8 pCi/L in the basement and 1.3 pCi/L on the first floor.
Initial Radon Mitigation Techniques
A 150-cfm heat recovery ventilator was installed to ventilate the entire home. A timer was
used to allow the HRV to run for 15 minutes per hour. Modeling the heat storage mass and its
interaction with the rest of the house indicated that it could not be excluded as a major source of
radon. Because of the house design, however, the storage mass could not be isolated from the living
space. Radon concentrations were monitored from March 7 to April 30, 1984. During this time
period, concentrations averaged 2.3 in the basement and 3.7 on the first floor.
Follow-Up Observations
During the follow-up visit, the HRV and timer were inspected and found to be operating
correctly. Discussions with the homeowners revealed the HRV was not operated during the summer
months when the windows were kept open. A short-term measurement was taken during the period
of July 7 to 12,1987. Radon concentrations averaged 0.8 pCi/L both in the basement and on the first
floor during this period.
Modified Radon Mitigation Techniques
No additional work was performed at this home. Alpha-track detectors were continuously
in place at this home from July 8,1987 through June 6,1988. Radon concentrations during this time
period averaged 5.7 pCi/L in the basement and 5.2 on the first floor.
Results
No additional work was performed at this home. The whole-house HRV maintained indoor
radon concentrations to a long-term average of 5.7 pCi/L in the basement and 5.2 pCi/L on the
3.9-1
-------
second floor. It is expected that an increase in the operation time of the HRV will further decrease
the average annual concentration below the 4 pCi/L level.
3.9-2
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INITIAL
POST-MITIGATION FOLLOW-UP
TEST PHASE
MODIFED
Figure 3.9-1. House NM-29. Comparison of Radon Measurements by Phase.
3.9-3
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3.10 HOUSE NM-31
Description
This two-level home has a finished lower level with some accessible floor/wall joints. There
are no provisions in the house design to isolate the lower level area from the upper level. The
foundation walls are hollow-core concrete blocks. It was not determined if the blocks tops were open
or sealed. Initial measurements made from October 7, to November 26, 1983 revealed an average
radon concentration of 15.5 pCi/L on the first floor. No lower level concentrations are available for
this time period.
Initial Radon Mitigation Techniques
Two separate sub-slab depressurization systems were installed in this home, one system on
each end of the house. Active ventilation for the systems was provided by axial computer type fans
(Dayton # 4C550). After installation of the systems, radon concentrations averaged 2.0 pCi/L in the
lower level and 1.3 pCi/L on the upper level.
Follow-Up Observations
During the follow-up inspection it was discovered that the fan for one of the systems (in a
bedroom) had become very noisy and was turned off by the homeowner. The fan in the other system
(in a utility room) was running properly. During the follow-up visit, the noisy fan was momentarily
re-activated and pressure differentials measured. Pressure differentials between the suction pipe in
the bedroom and lower level air were found to be 15 Pa. Utility room system pressure differentials
were 17 Pa. Airflows from both systems were approximately 30 cfm. Investigation with smoke sticks
revealed that cracks around the toilet and floor/wall joint on the lower level were allowing indoor air
to be drawn out of the home by the sub-slab systems. Leaks were found on the positive side of the
exhaust pipes, allowing radon-laden soil gas to blow back into the home. Charcoal canisters were
deployed at the time of the follow-up visit, but the homeowner did not send them to the lab for
analysis.
Modified Radon Mitigation Techniques
Both axial fans were replaced with 20-watt in-line centrifugal fans (Kanalflakt K4). Exhaust
pipe leaks and accessible floor/wall cracks were sealed with polyurethane caulk. A short-term test
using activated charcoal canisters revealed an average concentration of 0.9 pCi/L on the lower level
3.10-1
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and 1.3 pCi/L on the upper level. Long-term tests using alpha-track detectors disclosed average
radon concentrations of 1.1 pCi/L on the lower level and 0.9 pCi/L on the upper level.
Results
While changing the fans in the depressurization system resulted in a marked improvement in
the system pressure field, it had little or no effect upon the radon concentrations as compared to the
Phase IB measurements. It is suspected, but cannot be confirmed, due to the loss of the Phase 2A
measurements, that deactivating one of the systems resulted in radon concentrations higher than the
Phase IB measurements.
3.10-2
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PHASE 1A
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PHASE 18
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PHASE 2A
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TEST PHASE
MONITORING TYPE
PHASE 2B
ATD
Figure 3.10-1. House NM-31. Comparison of Radon Measurements by Phase.
3.10-3
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3.11 HOUSE NM-37
Description
This relatively new (less than 10 years old) colonial home was built with a full basement.
Foundation walls are poured concrete, with a poured concrete floor slab. The basement contains a
sump hole connected to an interior footing drain. The floor slab is also penetrated by a one-inch
wide French drain and several large floor cracks. Initial radon measurements, beginning August 17
and ending November 16, 1983, disclosed average concentrations of 28.3 pCi/L in the basement, 4.8
pCi/L on the first floor, and 4.9 pCi/L on the second floor.
Initial Radon Mitigation Techniques
A sump depressurization system was installed in this home. Active ventilation for the system
was provided by an axial computer-type fan (Dayton #4C550). The French drain was sealed with
closed-cell polyurethane foam insulation, and large floor cracks sealed with non-shrink grout with a
plastic binder (Acryl 60). All other accessible cracks were sealed with polyurethane caulk. Radon
measurements made with alpha-track detectors revealed average radon concentrations of 8.1 pCi/L
in the basement, 2.9 pCi/L on the first floor, and 3.6 pCi/L on the second floor during the monitoring
period from March 1 to April 27, 1984.
Follow-Up Observations
This home was sold after the initial radon mitigation system was installed. The new
homeowners were not informed about the installation and the fan was turned off. When informed
about the system and its function, the new homeowners re-activated the system. An inspection of
the exterior vent opening revealed that the louvered shutters on the dryer-type vent cover closed
when the prevailing winds blew directly at the opening. Pressure differentials between the suction
pipe and the basement air were measured at -18 Pa. No leaks were found in the pipe system or fan.
The closed-cell foam filling the French drain and the polyurethane caulk used to, seal floor and wall
penetrations were in good condition. Two short-term measurements were made at this home. The
first measurements, from September 26 to September 29, 1987, revealed average basement radon
concentrations of 11.3 pCi/L. First and second floor concentrations during this period were 4.1 pCi/L
and 3.1 pCi/L, respectively. The second set of measurements, made from November 17 to November
21, 1987, disclosed average concentrations of 6.2 pCi/L in the basement, 2.5 pCi/L on the first floor,
and 1.8 pCi/L on the second floor.
3.11-1
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Modified Radon Mitigation Techniques
Although the fan in the sump depressurization system was operating properly, it was decided
to replace the original fan with a 20-watt in-line centrifugal fan (Kanalflakt K4). The louvered
shutters on the exhaust cover were replaced with a screened opening and rain cap. Suction pipe to
basement pressure differentials generated by the new fan were measured at -120 Pa. A series of
long-term measurements were made at this home. Basement concentrations from November 17,1987
to March 25, 1988 averaged 2.7 pCi/L. First and second floor concentrations during this time
averaged 1.5 and 1.0 pCi/L, respectively. A second set of measurements were made from June 30
to December 16, 1988. Basement concentrations averaged 3.6 pCi/L, first floor concentrations
averaged 0.7 pCi/L, and second floor concentrations averaged 1.6 pCi/L.
Results
The modified mitigation system maintained long-term average concentrations less than the
4 pCi/L level. It is suspected that the increase in the strength of the negative pressure field caused
by changing the fans was the primary cause of the overall reductions. It is also suspected that
changing the cover of the exhaust pipe from one which closes when the wind is blowing from a
certain direction, to one which will not close had an impact on the indoor radon concentrations at
those times. However, these conditions occurred infrequently and probably did not have much impact
on the long-term radon concentrations. They may, however, have caused indoor concentrations to
elevate for the short-term.
3.11-2
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E3 BASEMENT
I ST FLOOR
2ND FLOOR
PHASE 1A
I TTN
MIU
PHASE IB
ATD
TEST PHASE
MONITORING TYPE
PHASE 2A
PHASE 28
AlU
Figure 3.11-1. House NM-37. Comparison of Radon Measurements by Phase.
3.11-3
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3.12 HOUSE NM-41
Description
This single-family, wood-frame colonial home rests on a half-basement and crawl space
substructure. The foundation walls are poured concrete. The basement floor slab is poured concrete
with two areas of bare earth floor. The crawl space floor is well ventilated with passive vents.
Openings in the floor/wall joint were evident. From September 20, 1982 to April 29, 1983, radon
measurements indicated average radon concentrations of 4.8 pCi/L in the basement, 2.0 pCi/L on the
first floor, and 3.7 pCi/L on the second floor.
Initial Radon Mitigation Techniques
The unpaved floor areas in the basement were filled with concrete and the floor/wall joint
cracks sealed with polyurethane caulk. To help reduce negative pressures, a thermal bypass from the
basement to the second floor was sealed. Radon measurements using alpha-track detectors revealed
average concentrations of 2.6 pCi/L in the basement, 1.6 pCi/L on the first floor, and 1.0 pCi/L on
the second floor from March 2, 1983 to April 3, 1983.
Follow-Up Observations
The polyurethane caulk sealing the floor/wall crack appeared to be in good condition. The
concrete slab that had been poured to cover the bare floor areas had a minor crack around the edges,
probably due to shrinkage while it dried. Short-term activated charcoal measurements indicated an
average concentration of 2.6 pCi/L in the basement and 3.3 pCi/L on the first floor.
Modified Radon Mitigation Techniques
No additional work was performed at this home. Long-term measurements beginning on
April 1, 1988 and ending March 16, 1989 revealed an average concentration of 3.4 pCi/L in the
basement.
Results
No additional work was performed at this home. Long-term radon concentrations averaged
below the 4 pCi/L level in the basement.
3.12-1
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PHASE 2A
GAC
TEST PHASE
MONITORING TYPE
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PHASE 28
Figure 3.12-1. House NM-41. Comparison of Radon Measurements by Phase.
3.12-2
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3.13 HOUSE NM-51
Description
This underground home had no visible cracks or openings in the building shell except for a
drain in the laundry room. It is suspected, but could not be confirmed due to interior finishes, that
some openings exist in the building shell. The layer of bentonite clay used for waterproofing the
underground portions may be restricting the flow of soil gases through any penetrations. The home
contained a rarely used heat recovery ventilator. Although radon concentrations averaged only 1.9
pCi/L from October 1,1982 to January 18, 1983, and 0.8 pCi/L from August 18 to November 4,1983,
it was decided to study this home to observe the long-term radon concentrations.
Initial Radon Mitigation Techniques
The floor drain in the laundry room was sealed. The existing HRV was equipped with a
humidistat to provide automatic operation. Prior to this, the HRV was manually operated only when
the homeowners noticed odors or stuffiness. Alpha-track detectors placed in the home from March
29, 1984 to May 2, 1984 indicated an average radon concentration of 1.0 pCi/L.
Follow-Up Observations
Conversations with the homeowners revealed that the HRV was activated only during the
winter months when the indoor relative humidity reached 60%. The HRV was turned off during the
warmer months when windows to the outside could provide ventilation. A short-term activated
charcoal measurement indicated an average concentration of 1.4 pCi/L from June 24 to June 27,1987
Modified Radon Mitigation Techniques
No additional work was performed at this home. Long-term measurements revealed an
average radon concentration of 1.8 pCi/L from June 24, 1987 to June 9, 1988.
Results
The original mitigation system installed in this home is maintaining the average indoor radon
concentration below the 4 pCi/L level.
3.13-1
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6-
BASEMENT
3-
2-
1 -
PHASE 1A
AID
PHASE1B
ATD
PHASE 2A
GAC
PHASE 2B
ATD
TEST PHASE
MONITORING TYPE
Figure 3.13-1. House NM-51. Comparison of Radon Measurements by Phase.
3.13-2
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3.14 HOUSE NM-56
Description
This single-family, wood-frame colonial home rests on a substructure consisting of a basement
and adjoining crawl space. The crawl space is used as passive thermal heat storage. Foundation walls
are constructed of hollow-core concrete block with numerous pipe penetrations. The basement and
crawl space floors are poured concrete with floor/wall joint cracks evident. Initial radon
measurements revealed average concentrations of 2.5 pCi/L in the basement, 1.7 pCi/L on the first
floor, and 1.2 pCi/L on the second floor from October 25, 1982 to January 26, 1983. A second
monitoring period, August 22 to November 22, 1983, indicated average radon concentrations of 2.0
pCi/L in the basement, 0.9 pCi/L on the first floor, and 1.0 pCi/L on the second floor.
Initial Radon Mitigation Techniques
The pipe penetrations in the foundation were sealed with polyurethane caulk, and the
opening between the crawl space and basement fitted with a tight-fitting door. A sight-built tube and
shell heat recovery ventilator was installed to provide basement ventilation. Radon concentration
over the period beginning March 20 and ending May 3, 1984 averaged 1.9 pCi/L in the basement and
0.9 pCi/L on the first floor. No second floor measurements were made during this period.
Follow-Up Observations
During this visit, it was discovered that the door isolating the crawl space from the basement
had been removed to allow easy access to the crawl space. The HRV was in good condition. A
short-term measurement from June 29 to July 2, 1987 indicated average radon concentrations of 1.8
pCi/L in the basement, 1.3 pCi/L on the first floor, and 2.4 pCi/L on the second floor.
Modified Radon Mitigation Techniques
The door isolating the crawl space from the basement was re-installed. Long-term
measurements from June 25, 1987 to June 7, 1988 indicated average radon concentrations of 1.8
pCi/L in the basement, 1.3 pCi/L on the first floor, and 1.1 pCi/L on the second floor.
Results
Re-installing the door isolating the crawl space had little or no effect on the long-term radon
concentrations in this home. Average concentrations were maintained below the 4 pCi/L level on
all floors.
3.14-1
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PHASE 1B
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PHASE 2A
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TEST PHASE
MONITORING TYPE
PHASE 28
ATD
Figure 3.14-1. House NM-56. Comparison of Radon Measurements by Phase.
3.14-2
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3.15 CONCLUSIONS
The mitigation techniques employed in this study can be divided into three main groups:
* Sealing of Radon Entry Points (NM-26 and NM-41)
* Heat Recovery Ventilation (NM-16, NM-19, NM-28, NM-29, NM-51, and NM-56)
* Sub-Slab Depressurization (NM-02, NM-05, NM-12, NM-21, NM-31, and NM-37).
Each of these three groups will be summarized.
Sealing of Radon Entry Points
The sealing that was performed in Houses NM-26 and NM-41 was the simplest and least
expensive technique employed. Unfortunately, the changes in radon concentrations are hard to
interpret, primarily due to the low initial concentrations and the accuracy of the measurement devices.
It is much easier to feel confident that a mitigation technique had some effect when the
concentrations drop from 100 pCi/L to 50 pCi/1, than when they drop from 6 pCi/L to 3 pCi/L. In
house NM-26, the initial post-mitigation monitoring indicated that the radon concentrations increased
in the basement and decreased on the first and second floors after the reduction techniques were
installed. This is possible because sealing radon entry points can cause the radon to migrate to and
enter the home through some other penetration. However, it is more likely that natural variations
in radon concentrations caused the changes. Follow-up testing tends to support this reasoning.
Radon concentrations on the first floor ranged from 1.5 pCi/L to 9.3 pCi/L and 0.8 pCi/L to 9.7 pCi/L
on the second floor during the long-term follow-up testing. The same holds true for house NM-41.
Initial radon concentrations were so low that natural variations and sampling accuracies could easily
account for the changes.
Data gathered from this task and other tasks within this project indicate the greatest problem
in sealing radon entry points is finding all of the openings so that the radon does not simply find
another path to enter the home.
The investigation of the sealants used during the original installation in all-houses indicated
that the polyurethane caulks can be expected to provide a longer service life than the less expensive
butyl caulks.
Heat Recovery Ventilation
The HRVs used for mitigation in the original project were easily installed by experienced
HVAC contractors, were economical to operate, provided the expected ventilation rate, required
3.15-1
-------
essentially no maintenance, and performed very quietly. Unfortunately, they did very little to reduce
the radon concentrations. The HRV in house NM-16 had very little impact upon the indoor radon
concentrations. Notice, however, that radon concentrations never exceeded the 4 pCi/L level in this
home, with or without the HRV in place and operating. This is also true for houses NM-51, and
NM-56. The HRV installed in house NM-19 also had very little, if any, impact on the indoor radon
concentrations, and basement concentrations in this home continue to exceed 4 pCi/L. This is also
true for houses NM-28 and NM-29.
Although the HRVs had little impact on the indoor radon concentrations, homeowners
mentioned other benefits such as reduced odor and humidity levels. Most homeowners were pleased
with the systems.
Sub-Slab Depressurization
The sub-slab depressurization systems installed in the homes demonstrated the greatest
reduction of radon levels. Unfortunately, lack of experience and proper materials, both of which are
plentiful today, caused these systems to also be the most problem prone.
The most serious problem occurred at house NM-05. Water that condensed and collected
in the exhaust pipe completely blocked airflow. The problem was exacerbated by poor quality butyl
caulk that failed to seal, causing radon to be blown into the home.
Another problem was the use of axial fans in the original systems. Axial fans are designed
to move large volumes of air at very low static pressures. Because of this narrow operating range of
the axial fans, and the low pressures at which they operate, these fans are not appropriate for
sub-slab depressurization systems. Negative pressures induced in the homes by combustion
appliances, and the wind and stack effects, can easily overcome the pressure field developed by the
axial fans and cause the sub-slab system to become ineffective. The ideal fan for sub-slab
depressurization systems should be able to move a wide volume of air at a wide range of static
pressures. Of interest, however, is the fact that all of the axial fans installed in the original project
were still operable, including the one that the homeowners turned off because it became noisy.
Outside vent openings also caused problems for two of the sub-slab depressurization systems.
The outside vent at house NM-37 faced directly into the prevailing winds and had movable louvers
which closed when the wind blew. Even though this most likely would not have happened with the
increased airflow provided by the in-line centrifugal fan, the vent was replaced with a screened rain
cover. House NM-21 also had an outside vent. This particular vent was only slightly above-grade
3.15-2
-------
level and was easily blocked by foreign materials. It is now standard procedure to terminate the
exhaust pipes above the roof of the house.
All sub-slab depressurization systems in this study had the fans located on the inside of the
house. Openings that develop on the positive side of the fan, between the fan and the end of the
pipe where it exits the house, can cause radon to be leaked into the basement, rather than exhausted
outside. These openings in the exhaust pipe can be created by loose fittings in the pipe joints or
cracks in the pipe itself. It is now standard procedure to place fans outside of a living area.
3.15-3
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SECTION 4
DEMONSTRATING RADON-RESISTANT NEW CONSTRUCTION TECHNIQUES
4.1 OVERVIEW
In this task radon-resistant construction techniques were applied to 15 new houses, with
simultaneous monitoring (and previous baseline monitoring) in five control houses. Emphasis was
placed on the development of cost-effective passive methods of radon-resistant construction with
potential applicability to building codes.
Housing site selection was critical to the success of this task because of the need to presume
high radon levels in houses not yet built. Ideally, subdivisions required the following characteristics:
1. Geologic features indicative of high radon concentrations.
2. Occupied new houses with high radon levels in close proximity to undeveloped
homesites.
3. Substructure types representative of standard construction.
4. A high annual rate of construction and sales so that test houses are likely to be
occupied during the duration of the research project.
5. Homebuilders/developers interested in participating in the project.
A study of 210 houses by Onondaga County Health Department in New York State's
Onondaga County (which includes Syracuse, NY) identified a band of bedrock with high radon levels,
which included the following formations: Marcellus Shale, Onondaga Limestone, Manlius Limestone,
Camillus Formation, and Syracuse Formation. Within this band of bedrock the distribution of heating
season screening measurements of radon were: 77 percent above 4 pCi/L, 22 percent above 20 pCi/L,
and one percent above 100 pCi/L. The highest levels were found over Onondaga Limestone and
Marcellus Shale.
Based on this information, several housing subdivisions in Onondaga County were identified
as possible candidates for this task. Subdivisions were chosen in locations where nearby houses had
radon levels greater than 20 pCi/L. These subdivisions were situated either on Onondaga Limestone
or Marcellus Shale. These sites were visited by a geologist and staff members from the New York
State Department of Health, who collected information on depth of soil to bedrock, bedrock faults,
fractures and joints, soil gas radon, soil and bedrock radium, and soil gas permeability. Homebuilders
4.1-1
-------
and/or developers of the subdivisions were also contacted in order to determine their interest and to
obtain information on their rate of construction. This narrowed the potential housing subdivisions
down to three. At two of these subdivisions, two control houses for each subdivision (four total)
were monitored with charcoal canisters. All four houses had basement radon levels above 10 pCi/L.
A fifth house that had previously been measured to have basement radon levels between 10 and 20
pCi/L was chosen as the control house in the third subdivision.
Control houses were included in this part of the project for the following reasons:
1) The control houses were located in close proximity to the test houses where the new
construction radon resistant techniques were to be evaluated. These control houses,
therefore, provided a comparison of radon levels for houses constructed with and
without the new radon resistant techniques. If the control houses indicated very low
radon concentrations, the results from the test houses would be inconclusive.
2) The control houses also gave a relative indication on how the radon levels varied
during the total test period and could be used for a normalization of data if it was
necessary. Fortunately, this normalization step was not needed during this project.
The control houses were also mitigated at the end of the project to lower the radon levels
below the EPA guidelines if possible. This step was performed to determine the level of effort
necessary to successfully reduce the radon levels and its associated cost.
These control houses were identified as ON-01 and ON-02 from the first subdivision; ON-04
and ON-05 from the second subdivision; and ON-03 from the third subdivision. (The prefix ON
abbreviates Onondaga County and new house study).
The following radon resistant techniques were applied to new houses ON-06 through ON-20.
Task 1: Install a continuous airtight plastic film (6 mil polyethylene or equivalent) over
the sub-slab aggregate to the foundation wall, before the slab is poured to the
wall and the wall/floor joint is caulked.
Discharge footing drains to daylight or dry well, whenever possible, to
avoid the introduction of radon into an interior sump. If footing
drains discharge into an interior sump, provide the sump liner with an
airtight lid ( that still allows access to service the sump pump).
Seal airtight any tears, punctures, slits, or penetrations of the plastic
film with builder's tape (3M 8086 or equivalent). Overlap the edges
4.1-2
-------
of any joining of the plastic film by at least three inches and seal
airtight with builder's tape (3M 8086 or equivalent).
Adhere the plastic film to the inside of the top of the footings with
bituminous adhesive or an equivalent adhesive to prevent radon from
entering the basement between the footing and the plastic film. Run
the plastic film up the side of the wall to provide a break between the
wall and the concrete slab.
Pour the concrete slab to the foundation wall. Strike the perimeter
of the slab to form a recessed rounded edge. After the slab sets, trim
the plastic film to below the slab level and fill the recessed rounded
edge with polyurethane caulk.
Use the recommended lean water content in the concrete mix to
minimize drying time and reduce shrinkage and cracks in the slab.
Task 2: Install a continuous layer of surface bonding cement (Comproco Foundation
Coat or equivalent) around the exterior foundation wall and footing. Ensure
that utility penetrations are sealed airtight.
Task 3: Install a course of termite blocks around the concrete block foundation wall
above finished grade level. If the footing is below the level of the sub-slab
aggregate (in order to build on undisturbed soil or provide for a walk-out,
basement), install a course of termite blocks, cap down, level with the
aggregate.
Task 4a: Provide for the ventilation of the footing drains (and sump, if any) directly
through the roof with the largest PVC pipe possible (four-inch diameter
minimum). The PVC pipe is to be initially capped at the slab surface, the
basement ceiling surface, and on the outside roof surface. Provide electrical
service to power a possible future fan inline with the PVC pipe, outside the
living area (for example, the attic).
or
Task 4b: Provide for ventilation of the footing drains and/or sump with a four-inch
4.1-3
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PVC pipe through the rim joist, venting at least ten feet from the nearest
window, door, or other opening into the building. The PVC pipe is to be
initially capped at the slab surface. At least two, and up to four vents are to
be used on opposite sides of the building.
or
Task 4c: Provide for the ventilation of the footing drains (and sump, if any) to the
outside using four-inch PVC pipes from the footing drains, along the outside
of the foundation wall, to finished drains, and to finished grade level. At least
two, and up to four, vents are to be used on opposite sides of the building,
venting at least ten feet from the nearest window, door, or other opening into
the building.
Not all of these tasks and subtasks were performed on every house. Task 2 was performed
on houses ON-06, ON-07, ON-08, and ON-18; the remaining houses used the traditional Portland
cement parget coat and bituminous coating. Task 4a was executed in only one house (ON-18).
Similarly, Task 4c was performed only in house ON-04.
Multiple phases were used to develop comparative data on the effectiveness of each
component of radon-resistant control techniques. For most of the test houses, Phase 0 was the
baseline situation with the vents from the sub-slab footing drain open to the basement. Phase 1
consisted of capping the sub-slab vent pipes; Phase 2 consisted of venting the sub-slab to the outside;
while Phase 3 consisted of capping all but one of the sub-slab vent pipes and actively depressurizing
the sub-slab with the remaining vent.
Continuous radon monitoring was used before and during each phase to obtain a detailed
record of the impact of each phase.
The data in this section summarize the key features of each of the 15 new test houses and
five control houses. A brief narrative describes house construction features followed by an outline
of the installed mitigation techniques and discussion of results. The tables for each house indicate
building characteristics, installed mitigation techniques and integrated radon concentrations. Figures
include a foundation floor plan and continuous radon results taken during each phase of mitigation.
4.1-4
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4.2 HOUSE ON-01 (CONTROL)
Description
Table 4.2-1 summarizes the characteristics of house ON-01. Figure 4.2-1 shows the
foundation floor plan. The house is a single-family colonial with a basement, a small crawl space and
an attached garage at grade level. It was built in 1987 in the same subdivision as control house ON-
02 and test house ON-17. The bedrock, which is near the surface, is highly fractured Onondaga
Limestone. The foundation was excavated directly into the fractured bedrock and bedrock debris was
used as backfill around the exterior of the foundation walls. Hollow-core concrete blocks, open at
the top, were used to build the foundation walls. The basement has a poured concrete floor slab with
a perimeter French drain. A complete interior footing drain is connected to an open sump. The
crawl space floor consists of crushed stone over the excavated bedrock with a polyethylene cover over
the crushed stone.
Combustion appliances in the basement include a gas-fired domestic water heater and forced-
air furnace.
Installed Mitigation Techniques
Table 4.2-2 summarizes the mitigation techniques tested in this house. Figure 4.2-2 shows
continuous radon measurement results during periods when the house was closed (Phase 0), when
the basement windows were open (Phase 1), and when the second floor windows were open (Phase
2). Figure 4.2-3 shows continuous radon measurements during pre-mitigation (Phase 0) and after the
basement was sealed and the basement sub-slab and crawl space sub-surface were depressurized
(Phase 3). Table 4.2-3 summarizes the integrated radon concentrations for each of the monitoring
periods indicated.
Before mitigation (Phase 0) the time weighted average concentrations (calculated from Table
4.2-3) were 71.7 pCi/L in the basement (16 day average), 37.5 pCi/L on the first floor (6 day
average), and 36.0 pCi/L on the second floor (6 day average).
4.2-1
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Phase 1. (Open Basement Windows') and Phase 2 fOpen Second Floor Windows). Between
March 3 and April 4, 1988, very high radon levels were measured using charcoal canisters (for
example, 104.0 pCi/L in the basement). After the results were known, the homeowners were advised
to vent the house as much as possible. The house was monitored again from April 15 to April 18,
1988, using charcoal canisters with windows open. During this period, radon concentrations fell to
24.0 pCi/L in the basement, 13.4 pCi/L on the first floor, and 12.2 pCi/L on the second floor. In
order to obtain information on the best methods to vent the house a series of tests was conducted
between July 7 and July 28, 1988. Figure 4.2-2 displays the results of these tests. There appeared
to be little difference between radon levels when the house was closed (Phase 0 time-weighted
average 88 pCi/L) and Phase 2 (time-weighted average 80 pCi/L), when the second floor windows
were open and the basement windows were closed. However, there appeared to be a dramatic drop
in radon levels during Phase 1 (time-weighted average 34 pCi/L) when the basement windows were
opened with second floor windows closed. These results may be explained by the fact that the
basement was not directly vented when the second floor windows were opened and the opening of
the second floor windows may have actually increased the stack effect and suction on the basement.
Phase 3. Seal Basement and Actively Depressurize Foundation. Phase 3 was installed by
the mitigation contractors on February 16, 1989. The mitigation system consisted of sealing the
French drain around the perimeter of the basement, sealing the sump, and depressurizing the
basement sub-slab and the crawl space subsurface by placing one suction point in the basement slab
near the crawl space and another suction point through the common block wall between the
basement and the crawl space. The common block wall suction point was connected to the sub-slab
interior footing drain with a four-inch PVC. pipe. The exhaust pipe from the basement slab suction
point was routed along the interior side wall of the garage, then through the garage attic, where the
fan was located, to the exterior of the house through the garage roof (see Figure 4.2-1). The labor
cost was $687.39 and the material cost was $804.00 for a total of $1,491.39.
Integrated radon levels in the basement were 2.4 pCi/L using the continuous radon monitor
and 3.2 pCi/L using a charcoal canister. The integrated radon level is calculated by summing the
hourly radon levels for the total monitored time period and dividing that total by the number of hours
in the period. This will result in an integrated average radon concentration for that monitored
period. This is also referred to as a time-weighted average. Charcoal canisters on the first and
second floors indicated radon levels of 1.7 pCi/L and 1.6 pCi/L, respectively (see Table 4.2-2).
4.2-2
-------
TABLE 4.2-1. HOUSE ON-01 (CONTROL)
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1987
PUBLIC
FOUNDATION STRUCTURE: 90% BASEMENT, 10% CRAWL SPACE
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
6 FEET (1.8 METERS)
CONCRETE BLOCK WITH OPEN TOPS
MINOR
BARE CONCRETE
SUMP, FRENCH DRAIN
CRUSHED STONE
INTERIOR COMPLETE LOOP TO SUMP
UPSTAIRS
AVERAGE HEIGHT OF CRAWL SPACE:
CRAWL SPACE WALLS:
CRAWL SPACE FLOOR SURFACE:
CRAWL SPACE VENTILATION:
CRAWL SPACE INSULATION:
ACCESS TO CRAWL SPACE:
4 FEET (1.2 METERS)
CONCRETE BLOCK
CRUSHED STONE
NONE
NONE
OPEN TO BASEMENT
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FAN
4.2-3
-------
HOLLOW CONCRETE BLOCK WAULS WFTH OPEN TOPS
KJ
CI1AWV. SPACE
OAriAOE
(OIXADG IEVCI)
pErnMeiEn mcfto i DOAJH
WKWLAO COHHEC1K)N
PIPE TO CfUWL SPACE
OWN
ACTIVE VENT TO OUTSIDE
SUMP WELL
(CWERED)
APPROXIMATE SCALE 1/0 INCH = 1 FOOT
Plguro 1.2-1. Mouso ON-01 (conlrol) foundation door plan
-------
TABLE 4.2-2. HOUSE ON-01 (CONTROL)
INSTALLED MITIGATION TECHNIQUES
PHASE 1 - OPEN BASEMENT WINDOWS AND CLOSE REMAINDER
OF HOUSE.
PHASE 2 OPEN SECOND FLOOR WINDOWS AND CLOSE REMAINDER
OF HOUSE.
PHASE 3 SEAL BELOW-GRADE OPENINGS AND ACTIVELY
DEPRESSURIZE BASEMENT SUB-SLAB AND CRAWL SPACE
SUB-SURFACE.
4.2-5
-------
120 -
ro
O
Q.
Ill
O
z
O
O
2
O
Q
UJ
S
LLJ
CO
<
03
100 -
Q 80 -
60 -
20 -
0
HOUSE CLOSED (PHASE 0)
SECOND FLOOR OPEN (PHASE 2)
SECOND FLOOR OPEN
(PHASE 2)
BASEMENT OPEN
(PHASE 1)
BASEMENT OPEN
(PHASE 1)
1
I
I
I
7/11/88 7/13/88 7/15/88 7/17/88 7/19/88 7/21/88 7/23/88 7/25/88 7/27/88
7/12/88 7/14/88 7/16/88 7/18/88 7/20/88 7/22/88 7/24/88 7/26/88
DATE (mm/dd/yy)
Figure 4.2-2. House ON-O1 (control) radon concentrations: house closed, basement open, and second floor open
-------
25
ro
O
a.
z
O
HI
O
z
O
O
O
Q
UJ
UJ
CO
<
CD
20 -
15 -
10 -
5 -
0
PHASE 0 - BASELINE
PHASE 3 - SEAL, DEPRESSURIZE SUB-SLAB
PHASED AVG. 13.5pCi/l
PHASE 3 AVQ. 2.4 pCi/1
EPA GUIDELINE (4 pCI/l)
/^ r^
V
r
A
T
I
2/14/09 2/15/09 2/16/09 2/17/09
DATE (mm/dd/yy)
Figure 4.2-3. House ON-01 (control) radon concentrations: phase 0 and phase 3
I
2/10/09
I
2/19/09
-------
TABLE 4.2-3. HOUSE ON-01 (CONTROL)
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION CoCi/L)
PHASE
0
0
0,1,2
0,1,2
1
0,1,2
1
2
1
2
1
2
0
1
0
1
2
0
2
1
0
3
3
MONITORING
DETECTOR* PERIOD
CC
CC
AT
CC
CR
AT
CR
CR
CR
CR
CR
CR
CR
CR
CR
CR
CR
CR
CR
CR
CR
CR
CC
11/15/87
03/31/88
03/31/88
04/15/88
07/11/88
07/11/88
07/11/88
07/12/88
07/13/88
07/14/88
07/15/88
07/16/88
07/16/88
07/19/88
07/19/88
07/22/88
07/23/88
07/24/88
07/26/88
07/27/88
02/14/89
02/16/89
02/17/89
- 11/18/87
- 04/03/88
- 07/11/88
- 04/18/88
- 07/12/88
- 11/16/88
- 07/12/88
- 07/13/88
- 07/14/88
- 07/15/88
- 07/16/88
1330-1930
- 07/19/88
1800-2130
- 07/22/88
- 07/23/88
- 07/24/88
- 07/26/88
- 07/27/88
- 07/28/88
- 02/16/89
- 02/20/89
- 02/20/89
BASEMENT
33.7
104.0
32.8
24.0
44.2
32.9
44.2
66.5
40.1
77.3
27.0
66.1
85.4
74.6
85.5
28.5
73.8
96.9
102.4
31.5
13.5
2.4
3.2
FIRST SECOND
FLOOR FLOOR
21.2 20.2
53.8 51.8
19.1
13.4 12.2
-
11.5
-
-
-
-
-
-
-
—
-
-
-
-
-
— -
— -
— —
1.7 1.6
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
4.2-8
-------
4.3 HOUSE ON-02 (CONTROL)
Description
Table 4.3-1 summarizes the characteristics of house ON-02. Figure 4.3-1 shows the
foundation floor plan. The house is a single-family colonial with a full basement and an attached
garage below grade level. It was built in 1987 in the same subdivision as control house ON-01 and
test house ON-17. The bedrock, which is near the surface, is highly fractured Onondaga Limestone.
The foundation was excavated directly into the fractured bedrock and bedrock debris was used as
backfill around the exterior of the foundation walls. Hollow-core concrete blocks, open at the top,
were used to build the foundation walls. The basement has a poured concrete floor slab with a
perimeter French drain. A complete interior footing drain is connected to an open sump.
Combustion appliances in the basement include a gas-fired domestic water heater and forced-
air furnace.
Installed Mitigation Technique
Table 4.3-2 summarizes the mitigation technique installed in this house. Figure 4.3-2 shows
continuous radon measurement results immediately before (Phase 0) and immediately after (Phase
3) the mitigation technique was installed. The mitigation system, installed on February 16, 1989,
consisted of sealing the French drain around the perimeter of the basement, sealing the sump, and
depressurizing the basement sub-slab with one suction point located in the basement slab near the
interior block wall separating the basement and garage. The exhaust pipe from the basement slab
suction point went through a closet in the laundry room, through the attic where the fan was located,
and to the exterior of the roof (see Figure 4.3-1). The labor cost was $749.88 and the material cost
was $814.00 for a total of $1,563.88.
Before mitigation (Phase 0), the time-weighted average concentrations (calculated from Table
4.3-3) were 7.2 pCi/L in the basement (98 day average) 6.5 pCi/L on the first floor (225 day average)
and 5.5 pCi/L on the second floor (225 day average).
After mitigation (Phase 3), integrated radon concentrations in the basement were 3.6 pCi/L
as measured by a continuous radon monitor and 2.7 pCi/L as measured by a charcoal canister.
Charcoal canisters on the first and second floors indicated radon levels of 1.8 pCi/L and 2.2 pCi/L,
respectively (see Table 4.3-3).
4.3-1
-------
TABLE 4.3-1. HOUSE ON-02 (CONTROL)
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1987
PUBLIC
FOUNDATION STRUCTURE: FULL BASEMENT
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
6 FEET (1.8 METERS)
CONCRETE BLOCK WITH OPEN TOPS
MINOR
BARE CONCRETE
SUMP, FRENCH DRAIN
CRUSHED STONE
INTERIOR COMPLETE LOOP TO SUMP
GARAGE, UPSTAIRS
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.3-2
-------
CO
I
W
OARAGE
(I1ELOW ORADG)
HOLLOW CONCRETE BLOCK WALLS WITH OPEN TOPS
• ACTIVE VENT
TO OUTSIDE
SUMP WELL
(COVERED)
OWN
PERIMETER FT1ENCH DRAIN
APPROXIMATE SCALE 1/8 INCH = 1 FOOT
Figure 4.3-1. House ON-Q2 (control) foundation floor plan
-------
TABLE 4.3-2. HOUSE ON-02 (CONTROL)
INSTALLED MITIGATION TECHNIQUES
PHASE 3 SEAL BELOW-GRADE OPENINGS (PERIMETER FRENCH DRAIN,
TOPS OF HOLLOW CONCRETE BLOCKS, AND SUMP OPENING)
AND ACTIVELY DEPRESSURIZE BASEMENT SUB-SLAB.
NOTE: PHASE 1 (SEAL BELOW-GRADE OPENINGS) AND PHASE 2
(SEAL BELOW-GRADE OPENINGS AND PASSIVELY VENT BASE-
MENT SUB-SLAB) WERE NOT SEPARATELY INSTALLED AND
MONITORED.
4.3-4
-------
25 -
W
I
en
O
CL
Z
O
1
LU
O
z
O
O
z
O
Q
111
UJ
V)
20
15
10 -
5 -
0 -
PHASE 0 - BASELINE
PHASE 3 - SEAL, DEPRESSURIZE SUB-SLAB
PHASE OAVG. 8.1 pCi/1
PHASE 3 AVG. 3.6 pCi/1
2/14/09 2/15/09 2/16/09 2/17/09 2/10/89
DATE (mm/dd/yy)
Figure 4.3-2. House ON-02 (control) radon concentrations: phase 0 and phase 3
2/19/89
2/20/09
-------
TABLE 4.3-3. HOUSE ON-02 (CONTROL)
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION foCi/D
MONITORING
PHASE DETECTOR* PERIOD BASEMENT
0 CC
0 AT
0 AT
0 CR
3 CR
3 CC
11/15/87
07/10/88
11/17/88
02/14/89
02/17/89
02/17/89
- 11/18/87 18.6
- 11/17/88
- 02/17/89 6.8
- 02/17/89 8.1
- 02/21/89 3.6
- 02/21/89 2.7
FIRST SECCND
FLOOR FLOOR
11.8 10.6
7.0 4.1
6.1 7.2
-
-
1.8 2.2
AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
4.3-6
-------
4.4 HOUSE ON-03 (CONTROL)
Description
Table 4.4-1 summarizes the characteristics of house ON-03. Figure 4.4-1 shows the
foundation floor plan. The house is a single-family colonial with full basement and attached garage
at grade level. It was built in 1986 in the same area as the test houses ON-06, ON-07, ON-08, ON-19
and ON-20. The bedrock which is near the surface is highly fractured Marcellus Shale. The
foundation was excavated directly into the black shale bedrock and bedrock debris was used as
backfill around the exterior of the foundation walls. Hollow-core concrete blocks with termite blocks
on the top course were used to build the foundation walls. The basement had a poured concrete
floor slab with a perimeter French dram. A complete interior footing drain is connected to an open
sump.
Combustion appliances in the basement include a gas-fired domestic water heater and forced-
air furnace.
Installed Mitigation Techniques
Table 4.4-2 summarizes the mitigation techniques installed in the house. Figure 4.3-2 shows
continuous radon measurement results immediately before (Phase 1) and after (Phase 3) the sub-slab
depressurization system was installed. Figure 4.3-3 shows continuous radon results after additional
sealing was performed (Phase 3A). Table 4.4-3 summarizes the integrated radon concentrations for
each of the monitoring periods indicated.
Phase 1. Seal French Drain and Sump. The first screening measurement in this house was
performed between December 7 and December 10, 1986. Radon concentrations in the basement
averaged 27.3 pCi/L. Soon after this measurement, the French drain was sealed with mortar and the
sump opening covered with an airtight seal by the builder. These measures did not reduce the radon
level in the basement or upstairs below the EPA guideline of 4 pCi/L. The time-weighted average
radon concentrations for Phase 1 (calculated from Table 4.4-3) were 17.0 pCi/L in the basement (588
day average), 4.5 pCi/L on the first floor (345 day average), and 7.3 pCi/L on the second floor (215
day average). No additional radon mitigation was performed at this site until the end of the project
so that the results of this control house could be used as a reference.
Phase 3. Seal Basement and Actively Depressurize Sub-Slab. Phase 3 was installed by the
mitigation contractor on February 14, 1989. The mitigation system consisted of depressurizing the
basement sub-slab with one suction point located in the basement slab behind the garage. The
exhaust pipe from the basement slab suction point exited along the interior back wall of the garage,
then through the garage attic where the fan was located, to the exterior of the garage roof (see
4.4-1
-------
Figure 4.4-1). The labor cost was $749.88 and the material cost was $699.00 for a total cost of
$1,448.88.
Integrated radon levels in the basement were 6.3 pCi/L using the continuous radon monitor
and 5.2 pCi/L using a charcoal canister. Charcoal canisters on the first and second floors indicated
radon levels of 2.6 pCi/L and 2.3 pCi/L respectively.
Phase 3A. Perform Additional Sealing and Actively Depressurize Sub-Slab. One week after
the sub-slab depressurization system was installed, the mitigation contractor sealed several large cracks
in the basement slab (the mitigation contractor did not have time to seal the cracks during the first
visit and the cost of Phase 3A is included in Phase 3). Integrated radon levels after additional sealing
were 1.8 pCi/L in the basement as measured by a continuous radon monitor (see Table 4.4-3).
4.4-2
-------
TABLE 4.4-1. HOUSE ON-03 (CONTROL)
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1985
PUBLIC
FOUNDATION STRUCTURE: FULL BASEMENT
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
6 FEET (1.8 METERS)
CONCRETE BLOCK WITH TOP COURSE
OF TERMITE BLOCKS
WEEPING HOLES AT BOTTOM COURSE
BARE CONCRETE
SUMP, FRENCH DRAIN, CRACKS
CRUSHED STONE
INTERIOR COMPLETE LOOP TO SUMP
UPSTAIRS
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.4-3
-------
£.
I
ACTIVE VENT
TOOUrsiDE
QAnAOE (OnAOG LEVEL)
HOLLOW CONCrtETE BLOCK WALLS WITH OPEN TOPS
PEfDMETEn niENCJ ( DfWN
runMAcE
SUMP WELL
(COVERED)
APPPOXIMATE SCALE 1/8 INCH = 1 FOOT
Figure 4.1-1. House ON-O3 (control) foundation floor plan
-------
TABLE 4.4-2. HOUSE ON-03 (CONTROL)
INSTALLED MITIGATION TECHNIQUES
PHASE 1 - SEAL BELOW-GRADE OPENINGS (PERIMETER FRENCH
DRAIN AND SUMP OPENING).
PHASE 3 - PHASE 1 PLUS ACTIVELY DEPRESSURIZE BASEMENT
SUB-SLAB.
PHASE 3A PHASE 3 PLUS SEAL FLOOR CRACKS.
NOTE: PHASE 2 (SEAL BELOW-GRADE OPENINGS AND PASSIVELY
VENT SUB-SLAB) WAS NOT SEPARATELY INSTALLED AND
MONITORED.
4.4-5
-------
25
i
CT)
20
O
O
I
LU
O
z
O
O
O
Q
LU
LU
(/)
<
m
15 -
10
0
PHASED-BASELINE
PI IASE 3 - SEAL, DEPRESSURIZE SUD-SLAD
PIIASEOAVG. H.3pCi/l
EPA GUIDELINE (1 pC\/\)
PHASE 3 AVG. 6.3 pCl/l
2/13/09 2/14/89 2/15/09 2/16/09 2/17/09 2/10/09 2/19/89 2/20/89
DATE (mm/dd/yy)
Figure ^.4-2. House ON-03 (control) radon concentrations: phaso 0 and phase 3
-------
25 -
A
20 -
O
ex
O
\-
15 -
O
2
O
O
z
O
Q
2
z
UJ
m
10 -
5 -
PHASE 3A - ADDITIONAL SEAL, DEPRESSUniZE SUD-SLAD
PIIASE3AAVG. 1.7pCi/l
EPA GUIDELINE (-1 pCI/1)
0
I I I I I I
3/20/89 3/22/89 3/24/89 3/2G/89 3/28/89 3/30/89 4/01/89 4/03/89 4/05/89
3/21/89 3/23/89 3/25/89 3/27/89 3/29/89 3/31/89 4/02/89 4/04/89 4/06/89
DATE (mm/dd/yy)
Figure 4.4-3. House ON-03 (control) radon concentrations: phase 3A
-------
TABLE 4.4-3. HOUSE ON-03 (CONTROL)
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (oCi/D
MONITORING
PHASE DETECTOR* PERIOD
0 CC
1 CC
1 CC
1 AT
1 AT
1 AT
1 CR
3 CR
3 CC
3A CR
12/07/86
01/11/87
11/15/87
03/15/88
07/11/88
11/16/88
02/13/89
02/15/89
02/17/89
03/20/89
- 12/10/86
- 01/14/87
- 11/18/87
- 07/11/88
- 11/16/88
- 02/15/89
- 02/15/89
- 02/21/89
- 02/21/89
- 04/07/89
BASEMENT
27.3
-
13.8
17.1
19.5
13.6
16.3
7.5
12.2
14.3
6.3
5.2
1.8
FIRST SECOND
FLOOR FLOOR
.
14.2 14.3
5.1 6.1
4.1 4.3
4.1
5.2 11.0
-
-
2.6 2.3
— —
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
4.4-8
-------
4.5 HOUSE ON-04 (CONTROL)
Description
Table 4.5-1 summarizes the characteristics of house ON-04. Figure 4.5-1 shows the
foundation floor plan. The house is a single-family colonial with basement, small crawl space, and
attached garage at grade level. It was built in 1987 in the same subdivision as control house ON-05
and test houses ON-09, ON-10, ON-11, ON-12, ON-13, ON-14, ON-15, and ON-16. The bedrock
which is near the surface is highly fractured Onondaga Limestone. The foundation was excavated
directly into the fractured bedrock and bedrock debris was used as backfill around the exterior of the
foundation walls. Hollow-core concrete blocks, open at the top, were used to build the foundation
walls. The basement has a poured concrete floor slab with a perimeter French drain. A complete
interior footing drain is connected to an open sump.
Combustion appliances in the basement include a gas-fired domestic water heater and forced-
air furnace.
Installed Mitigation Techniques
Table 4.5-2 summarizes the mitigation techniques installed in this house. Figure 4.5-2 shows
continuous radon measurement results while an exterior vent was alternatively opened (Phase 0) and
closed (Phase 0 ). Figure 4.5-3 indicates radon levels while mitigation techniques were installed on
a test house next door (house ON-09). Figure 4.5-4 shows continuous radon measurement results
immediately before (Phase 0) and immediately after (Phase 3) the mitigation technique was installed.
Figure 4.5-5 shows the continuous radon results after additional sealing was performed (Phase 3A).
Integrated radon concentrations for each of the monitoring periods is summarized in Table 4.5-3.
Before mitigation (Phase 0) the time-weighted average concentrations (calculated from Table
4.5-3) were 14.8 pCi/L in the basement (461 day-average), 9.2 pCi/L on the first floor (147 day
average), and 9.7 pCi/L on the second floor (273 day-average).
Phase 0': Close Exterior Sub-Slab Vent. An exterior vent pipe was installed by the builder
during the construction of the house (see Figure 4.5-1). The vent consisted of a four-inch PVC pipe
connected through the footing to the sub-slab aggregate and passing along the outside of the back
of the house to about three feet above grade level. This vent is normally kept open. In this phase,
an attempt was made to see if closing the exterior vent would have any effect on radon levels. The
first two periods seemed to indicate that there was a reduction of radon levels with the vent open
(from an average of 42.8 pCi/L to an average of 32.9 pCi/L, see Figure 4.5-2). During the third and
fourth monitoring periods, however, radon levels remained essentially unchanged from 32.9 pCi/L
after the vent was closed and then opened again (average radon levels went from 28.9 pCi/L to 28.8
4.5-1
-------
pCi/L). When the vent was closed again there did appear to be an increase of radon levels (from
28.8 pCi/L to 38.8 pCi/L) and then a slight (probably not significant) reduction (to 34.0 pCi/L) when
the vent was opened again (see Figure 4.5-2). Although results are inconclusive on the effect of the
exterior vent, it appears that reductions in radon levels were being overwhelmed by naturally induced
changes in radon levels.
Phase 3: Seal Basement and Actively Depressurize Sub-Slab. Phase 3 was installed by the
mitigation contractor on February 13, 1989. The mitigation system consisted of sealing the French
drain around the perimeter of the basement, sealing the sump, and depressurizing the basement sub-
slab and the crawl space sub-surface with one suction point located in the basement and one in the
crawl space. The common block wall suction point was connected to the sub-slab interior footing
drain with a four-inch PVC pipe. The surface of the crawl space was covered with a polyethylene
sheet which was sucked onto the surface when the system operated. At the homeowner's strong
request, the exhaust pipe from the basement slab exited through the band joist on the far side of the
house to minimize the visual impact and retain the integrity of the roof (see Figure 4.5-1). The labor
cost was $734.26 and the material cost was $722.00 for a total of $1,456.26.
After sealing and active depressurization, integrated continuous radon levels in the basement
were 4.2 pCi/L.
Phase 3A: Perform Additional Sealing and Actively Depressurize Sub-Slab. Additional
sealing of several large cracks in the basement slab was completed by the mitigation contractor about
a week after the sub-slab depressurization system was installed. (The mitigation contractor did not
have time to seal the cracks during the first visit and the cost of Phase 3A is included in Phase 3).
Integrated radon levels in the basement after additional sealing were 3.4 pCi/L as measured by both
a continuous radon monitor, and a charcoal canister. Charcoal canisters on the first and second floors
indicated radon levels of 1.9 pCi/L and 1.7 pCi/L, respectively (see Table 4.5-3).
4.5-2
-------
TABLE 4.5-1. HOUSE ON-04 (CONTROL)
BUILDING CHARACTERISTICS
^TYLE:
fEAR BUILT:
VATER SUPPLY:
COLONIAL
1987
PUBLIC
FOUNDATION STRUCTURE: 90% BASEMENT, 10% CRAWL SPACE
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
3ASEMENT FLOOR OPENINGS:
H5UB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
6 FEET (1.8 METERS)
CONCRETE BLOCK WITH OPEN TOPS
MINOR
BARE CONCRETE
SUMP, FRENCH DRAIN, CRACKS
CRUSHED STONE
INTERIOR COMPLETE LOOP TO SUMP
UPSTAIRS
AVERAGE HEIGHT OF CRAWL SPACE:
pRAWL SPACE WALLS:
(PRAWL SPACE FLOOR SURFACE:
8CRAWL SPACE VENTILATION:
CRAWL SPACE INSULATION:
ACCESS TO CRAWL SPACE:
4 FEET (1.2 METERS)
CONCRETE BLOCK
CRUSHED STONE
NONE
NONE
OPEN TO BASEMENT
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.5-3
-------
PASSIVE EXTEnion VENT PIPE
HOLLOW CONCHETE BLOCK WALLS WfTH OPEN TOPS
crww. SPACE
OAnAOE
(orwoe LEVEL)
SimSLAB CONNECTION PIPE
TO CNAWL SPACE
ruriMAcE
OWN
SUMP WELL 4fe
^y
(COVETCD) ^
ACTIVE VENT •
Tooorsioe
PEniMETEn mENCH OOAIN
APPROXIMATE SCALE 1/8 INCH = 1 FOOT
Figure 4.5-1. House ON-O4 (conlrol) foundation floor plan
-------
TABLE 4.5-2. HOUSE ON-04 (CONTROL)
INSTALLED MITIGATION TECHNIQUES
PHASE O'- CLOSE EXTERIOR PASSIVE SUB-SLAB VENT.
PHASE 3 SEAL BELOW-GRADE OPENINGS (PERIMETER FRENCH
DRAIN, TOPS OF HOLLOW CONCRETE BLOCKS, AND
SUMP OPENINGS) AND DEPRESSURIZE SUB-SLAB.
PHASE 3A PHASE 3 PLUS SEAL FLOOR CRACKS.
NOTE: PHASE 1 (SEAL BELOW-GRADE OPENINGS) AND PHASE 2
(SEAL AND PASSIVELY VENT BASEMENT SUB-SLAB)
WERE NOT SEPARATELY INSTALLED AND MONITORED.
4.5-5
-------
00 -
O GO
a.
z
O
H
£
LU
o
O 40
O
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o
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CO
20 -
0
PHASED-VENT OPEN
PHASED1-VENT CLOSED
PHASEO'AVG. '12.0pCi/l
PHASE O1 AVG. 30.0 pCi/1
PI IASEOAVG. 3-1.0 pCi/1
1 ~1 1 1 1 I I I I I I I 1 1 f
11/30/87 12/2/87 12/4/07 12/6/07 12/0/87 12/10/87 12/12/87 12/14/87
12/1/87 12/3/87 12/5/07 12/7/87 12/9/87 12/11/87 12/13/87
DATE (mm/dd/yy)
Figure 4.5-2. House ON-04 (control) radon concenlrallons: wllh exterior vent alternately open (phase 0) and closed (phase 0')
-------
25 -
O
Q.
O
I
UJ
O
z
O
O
z
O
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IU
m
20 -
15 -
10 -
5 -
0
PHASE 0 -BASEUNE
PHASE 3 - SEAL. DEPRESSURIZE SUB-SLAB
PHASE OAVG. 10.3pCi/l
T
2/10/89 2/11/09 2/12/09 2/13/09
DATE (mm/dd/yy)
Flguro 4.5-3. House ON-04 (conlrol) radon concentrations: phase 0 and phase 3
2/14/09
2/15/89
T
2/16/89
-------
00
25
20 -
O
CL
O
15
LLJ
O
Z
O
O
z
O
Q
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UJ
C/3
<
CQ
10
5 -
0
PI IASE 3A - ADDITIONAL SEAL. DEPRESSUniZE SUB-SLAB
3/21/89
PHASE 3A AVG. 3.1 pCI/1
EPA GUIDELINE (4 pCi/l)
3/22/09
DATE (dcl/mm/yy)
Figure 4.5-^1. Houso ON-04 (conlrol) radon concentrallons: phaso 3A
3/23/89
-------
TABLE 4.5-3. HOUSE ON-04 (CONTROL)
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (t>Ci/D
PHASE
0
O1
0
0'
0
0'
0
0
0
0
0
0
0
0
3
3A
3A
MONITORING
DETECTOR* PERIOD
CC
CR
CR
CR
CR
CR
CR
CR
CR
CR
AT
AT
AT
CR
CR
CR
CC
11/15/87
11/30/87
12/02/87
12/04/87
12/07/87
12/09/87
12/11/87
02/09/88
02/29/88
03/04/88
05/20/88
07/12/88
11/15/88
02/10/89
02/14/89
03/21/89
03/21/89
- 11/18/87
- 12/02/87
- 12/04/87
- 12/07/87
- 12/09/87
- 12/11/87
- 12/14/87
- 02/29/88
- 03/04/88
- 03/24/88
- 07/11/88
- 11/15/88
- 02/14/89
- 02/14/89
- 02/16/89
- 03/23/89
- 03/23/89
BASEMENT
19.3
42.8
32.9
28.9
28.8
38.8
34.0
24.0
23.5
24.6
25.8
24.4
18.3
18.9
18.3
4.2
3.4
3.4
FIRST SECOND
FLOOR FLOOR
15.4 13.9
- -
- -
- -
- -
- -
- -
- -
- -
- -
8.6 7.6
8.7
9.3 12.3
- -
- -
- -
1.9 1.7
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
4.5-9
-------
4.6 HOUSE ON-05 (CONTROL)
Description
Table 4.6-1 summarizes the characteristics of house ON-05. Figure 4.6-1 shows the
foundation floor plan. The house is a single-family colonial with a full basement and an attached
garage at grade level. It was built in 1987 in the same subdivision as control house ON-04 and test
houses ON-09, ON-10, ON-11, ON-12, ON-13, ON-14, ON-15, and ON-16. The bedrock, which is
near the surface, is highly fractured Onondaga Limestone. This house has an extensive sub-
foundation, which was excavated directly into the fractured bedrock. Bedrock debris was used as fill
in the sub-foundation cavity. Additional dirt fill was transported to the site. Hollow-core concrete
blocks, open at the top, were used to build the foundation walls. The basement has a poured
concrete floor slab with a perimeter French drain. A complete interior footing drain discharges to
daylight.
Combustion appliances in the basement include a gas-fired domestic water heater and forced-
air furnace.
Installed Mitigation Techniques
Table 4.6-1 summarizes the mitigation techniques installed in this house. Figure 4.6-2 shows
continuous radon measurement results immediately before (Phase 1) and immediately after (Phase
3) the mitigation technique was installed. Figure 4.6-3 shows the continuous radon results after
additional sealing was performed (Phase 3A). Integrated radon concentrations for each of the
monitoring periods is summarized in Table 4.6-3.
Phase 3. Seal Basement and Actively Depressurize Sub-Slab. Phase 3 was installed by the
mitigation contractor on February 12, 1989. The mitigation system consisted of sealing the French
drain around the perimeter of the basement and depressurizing the basement sub-slab. The exhaust
pipe from the basement slab suction point exited along the interior back wall of the garage, then
through the garage attic where the fan was located, to the exterior of the garage roof (see Figure 4.6-
1). The labor cost was $718.64 and the material cost was $671.00 for a total cost of $1,389.64.
Integrated radon levels in the basement were 1.7 pCi/L using the continuous radon monitor.
4.6-1
-------
Phase 3A. Perform Additional Sealing and Actively Depressurize Sub-Slab. Additional
sealing of several large cracks in the basement slab was performed by the mitigation contractor one
week after the sub-slab depressurization system was installed. (The mitigation contractor did not have
the equipment or the time to seal the cracks during the first visit and the cost of Phase 3 A is included
in Phase 3). Integrated radon levels in the basement, after additional sealing, were 3.1 pCi/L as
measured by a continuous radon monitor and 2.6 pCi/L as measured by a charcoal canister. Charcoal
canisters on the first and second floors indicated radon levels of 2.2 pCi/L and 1.9 pCi/L, respectively
(see Table 4.6-3).
4.6-2
-------
TABLE 4.6-1. HOUSE ON-05 (CONTROL)
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1987
PUBLIC
FOUNDATION STRUCTURE: WALK-OUT FULL BASEMENT
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
5 FEET (1.5 METERS)
CONCRETE BLOCK WITH OPEN TOPS
MINOR
BARE CONCRETE
FRENCH DRAIN, CRACKS
CRUSHED STONE
INTERIOR COMPLETE LOOP TO
DAYLIGHT
UPSTAIRS AND OUTSIDE
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.6-3
-------
A
b)
A
HOLLOW CONCRETE BLOCK WALLS WfTH OPEN TOPS
ACTIVE VENf
TO OUFSIDE
OAHAGE
(GIIAOE LEVEL)
FUWACE I DHW
OWN —
APPROXIMATE SCALE 1/8 INCH = 1 FOOT
Figure 4.6-1. House ON-05 (control) foundation floor plan
-------
TABLE 4.6-2. HOUSE ON-05 (CONTROL)
INSTALLED MITIGATION TECHNIQUES
PHASE 3 SEAL BELOW-GRADE OPENINGS (PERIMETER FRENCH
DRAIN, TOPS OF HOLLOW CONCRETE BLOCKS, SUMP
OPENINGS) AND DEPRESSURIZE SUB-SLAB.
PHASE 3A PHASE 3 PLUS SEAL FLOOR CRACKS.
NOTE: PHASE 1 (SEAL BELOW-GRADE OPENINGS) AND PHASE 2
(SEAL AND PASSIVELY VENT BASEMENT SUB-SLAB)
WERE NOT SEPARATELY INSTALLED AND MONITORED.
4.6-5
-------
O)
o>
O
a.
•z.
O
h-
UJ
O
~z.
O
O
z
O
Q
111
LU
w
25 -
20 -
15 -
10 -
0 -
PHASE 0 - BASELINE
PHASE 3 - SEAL, DEPRESSURIZE SUB-SLAB
PIIASEOAVG. 1G.3pCi/l
PMASE3AVG. 1.7pC!/l
EPA GUIDELINE (1 pCI/l)
sv
I
2/10/09 2/11/09 2/12/09 2/13/09 2/14/09
DATE (mm/dd/yy)
Figure 4.&-2. House ON-05 (control) radon concentrations: phase 0 and phase 3
2/15/09
2/16/09
-------
01
20
O
a.
Z
O
UJ
o
z
o
o
z
o
Q
UJ
UJ
CD
10 -
0 -L
Pl IASE 3A - ADDITIONAL SEAL, DEPRESSURIZE SUB-SLAB
PHASE 3AAVG. 3.1 pCi/1
EPA GUIDELINE (1 pCi/l)
3/20/09
3/21/09
3/22/09
DATE (mm/dd/yy)
Figure 4.6-3. llouso ON05 (control) radon concentrations: phase 3A
-------
TABLE 4.6-3. HOUSE ON-05 (CONTROL)
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION fpCi/L)
MONITORING
PHASE DETECTOR* PERIOD BASEMENT
0 CC
0 AT
0 AT
0 CR
3 CR
3A CR
3A CC
11/15/87
07/12/88
11/19/88
02/10/89
02/13/89
03/20/89
03/20/89
- 11/18/87
- 11/17/88
- 02/13/89
- 02/13/89
- 02/16/89
- 03/23/89
- 03/23/89
17.1
13.4
17.6
19.3
16.3
1.7
3.1
2.6
FIRST SECOND
FLOOR FLOOR
17.8 12.4
6.8
12.8 13.1
- -
- -
- -
2.2 1.9
AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
4.6-8
-------
4.7 HOUSE ON-06
Description
Table 4.7-1 summarizes the characteristics of house ON-06. Figure 4.7-1 shows the
foundation floor plan. The house is a single-family colonial with a basement and an attached garage
at ground level. The house was built in 1988 in the same area as test houses ON-07, ON-08, ON-19,
ON-20 and control house ON-03. The bedrock, which is near the surface, is highly fractured
Marcellus Shale. Hollow-core concrete blocks, with termite blocks on the top course were used to
build the foundation walls. Interior and exterior footing drains discharge to daylight.
Combustion appliances in the basement include a gas-fired domestic water heater and gas-
fired forced-air furnace.
Installed Mitigation Techniques
Table 4.7-2 summarizes the mitigation technique tested in this house. Table 4.7-3 summarizes
the integrated radon concentrations for each of the monitoring periods indicated.
Discussion of Results
Radon levels in this house have been consistently low, except for the period 7/18/88 to
11/19/88, when radon levels in the basement were slightly over the 4.0 pCi/L guideline. Time-
weighted average radon concentrations, calculated from Table 4.7-3, were 3.5 pCi/L in the basement
(507 day average), 1.8 pCi/L on the first floor (319 day average), and 1.6 pCi/L on the second floor
(255 day average).
There are two possible explanations for the favorable results: (1) Although the house was
built in an area where highly fractured Marcellus Block Shale is often just below the surface, the
basement of this house was excavated in deep clay soil; no black shale bedrock was found during
excavation. (2) This house was the first new house to be built in this research project and a great
deal of attention was spent in specifying the radon-resistant construction features, supervising the
foundation construction, and correcting any problems. Quality control for this house was ideal. With
the exception of a crack in the basement slab, there appeared to be no major below-grade openings
in this house. In addition, since the footing drains discharged to daylight, there was no sump to allow
radon to enter the home.
4.7-1
-------
TABLE 4.7-1. HOUSE ON-06
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1988
PUBLIC
FOUNDATION STRUCTURE: FULL BASEMENT
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
7 FEET (2.1 METERS)
CONCRETE BLOCK WITH TOP COURSE
OF TERMITE BLOCKS
NONE
BARE CONCRETE OVER PLASTIC FILM
ONE LONG CRACK
CRUSHED STONE
INTERIOR AND EXTERIOR DISCHARGE
TO DAYLIGHT
UPSTAIRS
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.7-2
-------
IIOLLOW CONCRETE BLOCK WALLS WITH TERMITE BLOCKS AT GRADE LEVEL
OJ
QAnAQE (GRADE LEVEU
APPROXIMATE SCALE 1/8 INCH = 1 FOOT
Figure 4.7-1. Houso ON-06 foundallon floor plan
-------
TABLE 4.7-2. HOUSE ON-06
INSTALLED MITIGATION TECHNIQUES
PHASE 0 - BASELINE RADON-RESISTANT CONSTRUCTION:
INSTALL CONTINUOUS AIRTIGHT POLYETHYLENE FILM OVER
AGGREGATE BEFORE SLAB IS POURED TO FOUNDATION WALL.
• ADHERE PLASTIC FILM TO TOP OF FOOTINGS WITH CAULK.
• TOOL PERIMETER EDGE OF SLAB AND FILL WITH URETHANE
CAULK.
INSTALL CONTINUOUS LAYER OF SURFACE BONDING CEMENT
AROUND EXTERIOR FOUNDATION WALL AND FOOTING.
INSTALL COURSE OF TERMITE BLOCKS ON TOP OF FOUNDATION WALL.
INSTALL EXTERIOR AND INTERIOR FOOTING DRAINS WHICH
DISCHARGE TO DAYLIGHT.
4.7-4
-------
TABLE 4J-3. HOUSE ON-06 (CONTROL)
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION fpCi/L^
MONITORING
PHASE DETECTOR* PERIOD BASEMENT
0 CC 03/03/88
0 AT 05/15/88
0 AT 07/18/88
0 AT 11/19/88
- 03/06/88 2.4
- 07/18/88
- 11/19/88 4.2
4.9
- 03/27/89 2.4
2.7
FIRST SECOND
FLOOR FLOOR
1.6 1.6
2.8
1.3 1.3
1.9 1.8
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
4.7-5
-------
4.8 HOUSE ON-07
Description
Table 4.8-1 summarizes the characteristics of house ON-07. Figure 4.8-1 shows the
foundation floor plan. The house is a single-family colonial with a basement and an attached garage
at ground level. The house was built in 1989 in the same area as test houses ON-06, ON-08, ON-19,
ON-20 and control house ON-03. The bedrock, which is near the surface, is highly fractured
Marcellus Shale. Hollow-core concrete blocks, with termite blocks on the top course were used to
build the foundation walls. Interior and exterior footing drains discharge into a sump.
Combustion appliances in the basement include a gas-fired domestic water heater and gas-
fired forced-air furnace.
Installed Mitigation Techniques
Table 4.8-2 summarizes the mitigation technique tested in this house. Figure 4.8-2 shows
continuous radon measurement results during Phases 0 and 1. Table 4.8-3 summarizes the integrated
radon concentrations for each of the monitoring periods indicated.
Discussion of Results
Radon levels in this house have been difficult to measure because the homeowner is often
away from home on business travel. From the limited data available (see Table 4.8-3) radon levels
in the basement were just over the 4.0 pCi/L guideline. Time-weighted average radon concentrations
for the basement during Phase 0 were 5.4 pCi/L (9 day average) and during Phase 1 were 7.1 pCi/L
(3 day average). Radon levels on the second floor were 3.2 pCi/L (3 day average). Radon levels
increased slightly after the sump was sealed. An explanation for this may be the fact that the
continuous radon monitor was approximately 20 feet (6 meters) from the sump and next to a crack
in the slab. When the sump was sealed, this may have forced radon through the floor crack (despite
the presence of an airtight plastic film below the slab). This house was an excellent candidate for
testing the effect of sealing the sump since both inside and outside surfaces of the foundation walls
were coated with surface bonding cement. Sealing the cracks in the basement slab and/or passively
venting the sump through the rim joist would be additional interesting phases, but, the homeowner
was not overly concerned about the radon levels and did not have a schedule that would permit these
additional tasks to be performed.
4.8-1
-------
TABLE 4.8-1. HOUSE ON-07
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1989
PUBLIC
FOUNDATION STRUCTURE: FULL BASEMENT
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
6 FEET (1.8 METERS)
CONCRETE BLOCK WITH TOP COURSE
OF TERMITE BLOCKS CLOSED TOPS
UNKNOWN
BARE CONCRETE OVER PLASTIC FILM
SEVERAL CRACKS
CRUSHED STONE
EXTERIOR AND INTERIOR DISCHARGE
TO SUMP
UPSTAIRS
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.8-2
-------
00
CO
HOLLOW CONCRETE BLOCK WALLS WITH TERMITE BLOCKS AT GRADE LEVEL
I SLIMP WELL (COVERED)
OAnAQE
(OnADE LEVEL)
APPROXIMATE SCALE 1/0 INCH = 1 FOOT
Figure 4.8-1. House ON-07 foundation floor plan
-------
TABLE 4.8-2. HOUSE ON-07
INSTALLED MITIGATION TECHNIQUES
PHASE 0 - BASELINE RADON-RESISTANT CONSTRUCTION:
INSTALL CONTINUOUS AIRTIGHT POLYETHYLENE FILM OVER
AGGREGATE BEFORE SLAB IS POURED TO FOUNDATION WALL.
• ADHERE PLASTIC FILM TO TOP OF FOOTINGS WITH CAULK.
• TOOL PERIMETER EDGE OF SLAB AND FILL WITH URETHANE
CAULK.
INSTALL CONTINUOUS LAYER OF SURFACE BONDING CEMENT AROUND
EXTERIOR AND INTERIOR OF FOUNDATION WALL AND FOOTING.
INSTALL COURSE OF TERMITE BLOCKS ON TOP OF FOUNDATION WALL.
INSTALL EXTERIOR AND INTERIOR FOOTING DRAINS WHICH
DISCHARGE TO OPEN SUMP.
PHASE 1 SEAL SUMP OPENING.
4.8-4
-------
25 -
CD
I
20 -
O
a.
z
O
I
z
LU
O
z
O
O
Z
O
Q
UJ
15 -
10 -
5 -
0
PHASE 0 - BASELINE
PHASE 1 - SEAL
PHASE 1 AVG. 7.1 pCI/l
PHASE 0 AVG. 5.1 pCi/1
EPA GUIDELINE (-1 pCi/I)
T
4/03/09 4/04/09 4/05/09 4/06/09 4/07/09 4/00/09 4/09/09 4/10/09 4/11/09 4/12/09 4/13/89
DATE (mm/dd/yy)
Flguro 4.0-2. Mouse ON-07 radon concentrations: phase 0 and phaso 1
-------
TABLE 4.8-3. HOUSE ON-07
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION
MONITORING FIRST
PHASE DETECTOR* PERIOD BASEMENT FLOOR
0 CC 01/10/89 - 01/13/89 2.4 3.2
0 CR 04/05/89 - 04/11/89 5.4
1 CR 01/11/89 - 04/14/89 7.1
(DCi/L)_
SECOND
FLOOR
-
—
*CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
4.8-6
-------
4.9 HOUSE ON-08
Description
Table 4.9-1 summarizes the characteristics of house ON-08. Figure 4.9-1 shows the
foundation floor plan. The house is a single-family colonial with a basement, crawl space, and an
attached garage at ground level. The house was built in 1988 in the same area as test houses ON-06,
ON-07, ON-19, ON-20 and control house ON-03. The bedrock, which is near the surface, is highly
fractured Marcellus Shale. Hollow-core concrete blocks, with a mortar filled top course, were used
to build the foundation walls. Interior and exterior footing drains discharge to daylight. Provisions
were made for venting the footing drains and sub-slab to the outside in one location.
Combustion appliances in the basement include a gas-fired domestic water heater and gas-
fired forced-air furnace.
Installed Mitigation Techniques
Table 4.9-2 summarizes the mitigation technique tested in this house. Table 4.9-3 summarizes
the integrated radon concentrations for each of the monitoring periods indicated.
Discussion of Results
Radon levels in the basement of this house were just over the 4.0 pCi/L guideline (see Table
4.9-3). Time-weighted average concentrations were 4.5 pCi/L in the basement (410 days average),
2.2 pCi/L on the first floor (255 days average), and 3.3 pCi/L on the second floor (100 day average).
No continuous radon measurements were collected at this site because of the low measured radon
levels of the charcoal canister and alpha-track results.
This house was built by the same builder as houses ON-06 and ON-07 and is in the same
subdivision as these houses. Like these two houses, no black shale bedrock was found during the
excavation of the basement, and there appeared to be no major below-grade openings in the
foundation. Like ON-06 (but unlike ON-07) the footing drains discharged to daylight.
4.9-1
-------
TABLE 4.9-1. HOUSE ON-08
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
19S8
PUBLIC
FOUNDATION STRUCTURE: 70% BASEMENT, 30% CRAWL SPACE
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
6 FEET (1.8 METERS)
CONCRETE BLOCK WITH A MORTAR
FILLED TOP COURSE
NONE
BARE CONCRETE OVER PLASTIC FILM
NONE
CRUSHED STONE
INTERIOR COMPLETE LOOP TO
VENTED SUMP
UPSTAIRS
AVERAGE HEIGHT OF CRAWL SPACE:
CRAWL SPACE WALLS:
CRAWL SPACE FLOOR SURFACE:
CRAWL SPACE VENTILATION:
CRAWL SPACE INSULATION:
ACCESS TO CRAWL SPACE:
4 FEET (1.2 METERS)
CONCRETE BLOCK WITH A MORTAR
FILLED TOP COURSE
BARE CONCRETE
NONE
NONE
FROM BASEMENT
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS .AND. OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.9-2
-------
(0
u
HOLLOW CONCRETE BLOCK WALLS WfTH TOP COURSE FILLED WfTH MORTAR
PASSIVE VENf CAPPED
CRAWL SPACE
OAHAOE
(QRADG UEVEl)
APPROXIMATE SCALE 1/8 INCH = 1 FOOT
Figure 4.9-1. House ON-00 foundation floor plan
-------
TABLE 4.9-2. HOUSE ON-08
INSTALLED MITIGATION TECHNIQUES
PHASE 0 BASELINE RADON-RESISTANT CONSTRUCTION:
INSTALL CONTINUOUS AIRTIGHT POLYETHYLENE FILM OVER
AGGREGATE BEFORE SLAB IS POURED TO FOUNDATION WALL.
• ADHERE PLASTIC FILM TO TOP OF FOOTINGS WITH CAULK.
• TOOL PERIMETER EDGE OF SLAB AND FILL WITH URETHANE
CAULK.
INSTALL CONTINUOUS LAYER OF SURFACE BONDING CEMENT
AROUND EXTERIOR FOUNDATION WALL AND FOOTING.
INSTALL COURSE OF MORTAR FILLED BLOCKS ON TOP OF FOUNDA-
TION WALL.
INSTALL EXTERIOR AND INTERIOR FOOTING DRAINS WHICH
DISCHARGE TO DAYLIGHT.
TABLE 4.9-3. HOUSE ON-08
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (DCi/U
PHASE
0
0
0
DETECTOR*
CC
AT
AT
MONITORING
PERIOD
03/03/88
07/18/88
12/20/88
- 03/06/88
- 12/20/88
- 03/27/88
BASEMENT
3.5
4.1
4.7
4.8
FIRST
FLOOR
3.1
1.8
2.8
SECOND
FLOOR
2.7
—
3.3
AT = ALPHA TRACK, CC = CHARCOAL CANISTER
4.9-4
-------
4.10 HOUSE ON-09
Description
Table 4.10-1 summarizes the characteristics of house ON-09. Figure 4.10-1 shows the
foundation floor plan. The house is a single-family colonial with a basement, a crawl space, and an
attached garage at ground level. The house was built in 1988 in the same subdivision as test houses
ON-10, ON-11, ON-12, ON-13, ON-14, ON-16, and control houses ON-04 and ON-05. The bedrock,
which is near the surface, is highly fractured Onondaga Limestone. The foundation was excavated
directly into the fractured bedrock and the bedrock debris was used as backfill around the exterior
of the foundation walls. Hollow-core concrete blocks, with termite blocks at grade level, were used
to build the foundation walls. A complete loop of interior footing drains discharge into a sump in
the basement. Provisions were made for venting the footing drains and sub-slab to the outside in
three locations.
Combustion appliances in the basement include a gas-fired domestic water heater and gas-
fired forced-air furnace.
Installed Mitigation Techniques
Table 4.10-2 summarizes the mitigation techniques tested in this house. Figures 4.10-2,4.10-3,
and 4.10-4 show continuous radon measurement results during Phases 0 to 3. Table 4.10-3
summarizes the integrated radon concentrations for each of the monitoring periods indicated.
Discussion of Results
Radon levels in the basement of this house (see Table 4.10-3) at first were only moderately
elevated (45 day time weighted average of 0.2 pCi/L). However, alpha-track results indicated much
higher basement radon levels (29.1 pCi/L) after the grounds were landscaped by grading top soil over
highly fractured bedrock that was used as backfill. A possible explanation for the change in radon
levels is that after the rock backfill was covered with top soil, the radon was 'trapped below the
surface in highly permeable material which could then be drawn into the house, whereas before, the
radon could escape to the atmosphere above.
Referring to Figure 4.10-3, the continuous radon results are consistent with the explanation
that radon levels were highest when the radon was allowed to vent from the footing drains into the
basement (Phase 0 average 38.9 pCi/L); radon levels were reduced somewhat when the footing
drains were sealed off from the basement (Phase 1 average 32.1 pCi/L) and were reduced even
further when the footing drains were vented to the outside (Phase 2 average 19.4 pCi/L). However,
it is unclear how significant these results are, since there are wide variations of radon levels over
4.10-1
-------
those periods. In any case, the passive techniques of Phases 1 and 2 could not reduce radon levels
below the 4 pCi/L guideline. Only active sub-slab depressurization of the basement and crawl space
effectively reduced radon levels below the guideline. Basement radon levels during Phase 3 were 1.2
pCi/L according to a continuous monitor and 1.1 pCi/L according to a charcoal canister. Phase 3
charcoal canister results on the first and second floor were 0.7 pCi/L and 0.8 pCi/L, respectively (see
Table 4.10-3).
4.10-2
-------
STYLE:
YEAR BUILT:
WATER SUPPLY:
TABLE 4.10-1. HOUSE ON-09
BUILDING CHARACTERISTICS
COLONIAL
1988
PUBLIC
FOUNDATION STRUCTURE: 60% BASEMENT, 40% CRAWL SPACE
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
6 FEET (1.8 METERS)
CONCRETE BLOCK WITH TERMITE
BLOCKS AT GRADE LEVEL
MISSING TERMITE BLOCKS
BARE CONCRETE OVER PLASTIC FILM
NONE
CRUSHED STONE
INTERIOR COMPLETE LOOP TO VENTED
SUMP
UPSTAIRS
AVERAGE HEIGHT OF CRAWL SPACE:
CRAWL SPACE WALLS:
CRAWL SPACE FLOOR SURFACE:
CRAWL SPACE VENTILATION:
CRAWL SPACE INSULATION:
ACCESS TO CRAWL SPACE:
4 FEET (1.2 METERS)
CONCRETE BLOCK WITH TERMITE
BLOCKS AT GRADE LEVEL
BARE CONCRETE
NONE
NONE
OPEN TO BASEMENT
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.10-3
-------
HOLLOW CONCRETE BLOCK WALLS WfTI I TERMfTE BLOCKS AT GRADE LEVEL
PASSIVE VENT TO INSIDE (PHASE 0)
PASSfVE VENT CAPPED (PtIASE 1)
PASSIVE VENT TO OUTSIDE (PtIASE 2)
ACTIVE VENT TO OUTSIDE (PHASE 3)
O
I
OA/W3E (QFVIDE LEVEL)
PASSIVE VENT TO INSIDE (PI 1ASE 0) •
PASSIVE VEMT CAPPED (PHASES t t 3)
PASSIVE VENT TO OUTSIDE (PHASE 2)
(sr
CP^WL SPACE
PASSIVE VENT TO INSIDE (PI IASE 0)
PASSfVE VENT CAPPED (PHASE 1)
PASSfVE VENT TO OUTSIOE (PtIASE 2)
ACTIVE VENT TO OUTSIDE (PHASE 3)
APPROXIMATE SCALE 1/8 INCH - 1 FOOT
Figure 4.1O-1. House ON-09 foundation floor plan
-------
TABLE 4.10-2. HOUSE ON-09
INSTALLED MITIGATION TECHNIQUES
'EASE 0 - BASELINE RADON-RESISTANT CONSTRUCTION:
INSTALL CONTINUOUS AIRTIGHT POLYETHYLENE FILM OVER AGGREGATE
BEFORE SLAB IS POURED TO FOUNDATION WALL.
• ADHERE PLASTIC FILM TO TOP OF FOOTINGS WITH CAULK.
• TOOL PERIMETER EDGE OF SLAB AND FILL WITH URETHANE
CAULK.
INSTALL CONTINUOUS LAYER OF PORTLAND CEMENT WITH BITUMINOUS
COATING AROUND EXTERIOR FOUNDATION WALL AND FOOTING.
INSTALL COURSE OF TERMITE BLOCKS AT GRADE LEVEL.
INSTALL INTERIOR FOOTING DRAINS (WHICH DISCHARGE INTO AIR-
TIGHT SUMP) IN BASEMENT AND CRAWL SPACE. PROVIDE FOR VENTING
FOOTING DRAINS AND SUB-SLABS IN THREE LOCATIONS. FOR PHASE 0,
VENT SUB-SLABS INTO BASEMENT AND CRAWL SPACE.
?HASE 1 - SEAL BELOW-GRADE OPENINGS AND CAP THREE VENTS.
fHASE 2 - SEAL BELOW-GRADE OPENINGS AND PASSIVELY VENT BASEMENT
CRAWL SPACE SUB-SLABS TO OUTSIDE USING THREE VENTS AT
RIM JOIST.
i'HASE 3 - SEAL BELOW-GRADE OPENINGS, CAP ONE VENT IN BASEMENT, AND
ACTIVELY DEPRESSURIZE BASEMENT AND CRAWL SPACE SUB-SLABS
USING TWO VENTS.
4-10-5
-------
00 -
o
i
6 GO
a.
Z
O
i
uu
o
z
O <10
o
z
o
Q
z
UJ
LU
(/)
<
CD
20 -
0 -
PI IASE 2 - SEAL, VENT SUD-SLAD
PIIASE2AVG. 10.7pCVl
EPA GUIDELINE (1 pCi/1)
1/11/09
1/12/09
1/13/09 1/14/89
DATE (mm/dd/yy)
1/15/89
Figure 4.10-2. House ON-09 radon concentrations: phase 2
-------
00
o
o GO
a.
2
O
LU
O
O 40
O
z
o
Q
UJ
LU
CQ
20 -
PI IASE 0 - BASELINE
PHASE 1 - SEAL
PHASE 2 - SEAL, VENT SUB-SLAB
PHASE 3 - SEAL, DEPRESSURIZE SUB-SLAB
PHASE OAVG. 30.9 pCi/l
PHASE1 AVG. 32.1 pCi/1
PIIASE2AVG. 19.4pCi/l
0 -~] 1 1 1 I I I T ,
1/25/09 1/26/09 1/27/09 1/20/09 1/29/09 1/30/09 1/31/09 2/1/09 2/2/09 2/3/09 2/4/09 2/5/09 2/6/09
DATE (mm/dd/yy)
Flguro 4.10-3. llouso ON-09 radon concentrations: pliaso 0, phaso 1, phase 2, and phase 3
-------
TABLE 4.10-3. HOUSE ON-09
INTEGRATED RADON CONCENTRATIONS
MONITORING
PHASE DETECTOR* PERIOD
0** CR
0** CC
0** CR
0 AT
2 CR
2 CR
1 CR
0 CR
3 CR
3 CC
02/09/88
03/01/88
03/04/88
07/12/88
01/11/89
01/26/89
01/27/89
01/30/89
02/01/89
02/03/89
- 03/01/88
- 03/04/88
- 03/25/88
- 11/19/88
- 01/16/89
- 01/27/89
- 01/30/89
- 02/01/89
- 02/06/89
- 02/06/89
RADON CONCENTRATION
FIRST
BASEMENT FLOOR
5.5
8.0 4.4
6.7
29.1 10.1
19.7
19.4
32.1
38.9
1.2
1.1 0.7
(DCi/Ll
SECOND
FLOOR
4.7
-
8.0
-
-
-
-
-
0.8
*AT = ALPHA TRACK DETECTOR, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
**ROCK BACKFILL AROUND FOUNDATION NOT COVERED WITH TOP SOIL
4.10-8
-------
4.11 HOUSE ON-10
Description
Table 4.11-1 summarizes the characteristics of house ON-10. Figure 4.11-1 shows the
foundation floor plan. The house is a single-family colonial with a basement and an attached garage
at ground'level. The house was built in 1988 in the same subdivision as test house ON-09, ON-11,
ON-12, ON-13, ON-14, ON-15, ON-16, and control houses ON-04 and ON-05. The bedrock, which
is near the surface, is highly fractured Onondaga Limestone. This house has a sub-foundation along
the front wall which was excavated well below the level of the basement slab. Fractured bedrock
from an adjoining site was used as backfill for this house. Hollow-core concrete blocks, with termite
blocks at grade level, were used to build the foundation walls. A complete loop of interior footing
drains discharge into a sump. Provision was made for venting the footing drains and sub-slab to the
outside in two locations.
Combustion appliances in the basement include a gas-fired domestic water heater and gas-
fired forced-air furnace.
Installed Mitigation Techniques
Table 4.11-2 summarizes the mitigation techniques tested in this house. Table 4.11-3
summarizes the integrated radon concentrations for each of the monitoring periods indicated.
Discussion of Results
Radon levels in the basement of house ON-10 at first were much lower than the 4 pCi/L
guideline (see Table 4.11-3). Later alpha-track results indicated higher radon concentrations (6.2 and
7.8 pCi/L in the basement, 4.0 pCi/L on the first floor, and 4.1 pCi/L on the second floor). A
possible explanation for these results may be similar to the explanation for the house next door
(house ON-09). For both houses ON-10 and ON-09 top soil was graded over the highly fractured
bedrock that was used as backfill around the foundation of the houses, making ;it more likely that
radon would be sealed in the nonpermeable soil around the houses. The radon levels were reduced
by capping one of the passive vents and providing a small inline fan for the second vent so that the
basement sub-slab was actively depressurized. Basement radon levels were dramatically reduced to
approximately 0.2 pCi/L (See Table 4.11-3).
4.11-1
-------
TABLE 4.11-1. HOUSE ON-10
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1988
PUBLIC
FOUNDATION STRUCTURE: FULL BASEMENT
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
6 FEET (1.8 METERS)
CONCRETE BLOCK WITH TERMITE
BLOCKS AT GRADE LEVEL
MISSING TERMITE BLOCKS, OPEN
PILASTERS
BARE CONCRETE OVER PLASTIC FILM
SEVERAL CRACKS
CRUSHED STONE
INTERIOR COMPLETE LOOP TO
VENTED SUMP
UPSTAIRS
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.11-2
-------
IIOLLOW CONCRETE BLOCK WALLS WfTI I TERMfTE BLOCKS ON TOP COURSE
QAJIAOE (OIXADGIEVCI)
pAssrve vorr to OUTSIDE
OWN
PASSWE VENT TO OUIS1D6
-IT-
APPROXIMATE SCALE 1/8 INCH = 1 FOOT
Tlytiro 1.11-1. Moiiso ON-IO fouridallon floor plan
-------
TABLE 4.11-2. HOUSE ON-10
INSTALLED MITIGATION TECHNIQUES
PHASE 0 BASELINE RADON-RESISTANT CONSTRUCTION
INSTALL CONTINUOUS AIRTIGHT POLYETHYLENE FILM OVER
AGGREGATE BEFORE SLAB IS POURED TO FOUNDATION WALL.
» ADHERE PLASTIC FILM TO TOP OF FOOTINGS AND
FOUNDATION WALLS WITH BITUMINOUS ROOFING CEMENT.
• TOOL PERIMETER EDGE OF SLAB AND FILL WITH URETHANE
CAULK.
INSTALL CONTINUOUS LAYER OF PORTLAND CEMENT WITH BITUMI-
NOUS COATING AROUND EXTERIOR FOUNDATION WALL AND FOOTING.
INSTALL COURSE OF TERMITE BLOCKS AT GRADE LEVEL.
INSTALL INTERIOR FOOTING DRAINS (WHICH DISCHARGE INTO
AIR-TIGHT SUMP) IN BASEMENT. PROVIDE FOR VENTING FOOTING
DRAINS AND SUB-SLAB IN TWO LOCATIONS. FOR PHASE 0, VENT
SUB-SLAB TO OUTSIDE AT RIM JOIST.
PHASE 1 SEAL BELOW-GRADE OPENINGS, CAP ONE VENT IN BASEMENT, AND
ACTIVELY DEPRESSURIZE BASEMENT SUB-SLAB USING SECOND VENT.
4.11-4
-------
TABLE 4.11-3. HOUSE ON-10
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (DCi/L)
MONITORING
PHASE DETECTOR* PERIOD BASEMENT
0 CC 03/18/88
0 CC 03/21/88
0 AT 12/09/88
1 CR 05/12/89
- 03/21/88 2.1
- 03/24/88 1.3
- 04/07/89 6.2
7.8
- 05/15/89 0.2
FIRST SECOND
FLOOR FLOOR
2.1 1.5
1.0 0.9
4.0 4.1
— —
*AT = ALPHA TRACK DETECTOR, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
4.11-5
-------
4.12 HOUSE ON-11
Description
Table 4.12-1 summarizes the characteristics of house ON-11. Figure 4.12-1 shows the
foundation floor plan. The house is a single-family colonial with a walk-out basement and an
attached garage at ground level. The house was built in 1988 in the same subdivision as test houses
ON-09, ON-10, ON-12, ON-13, ON-14, ON-15, ON-16, and control houses ON-04 and ON-05. The
bedrock, which is near the surface, is highly fractured Onondaga Limestone. The walk-out basement
at the back of the house has a sub-foundation, excavated well below the level of the basement slab.
Hollow-core concrete blocks, with termite blocks at grade level, were used to build the foundation
walls. A complete loop of interior footing drains discharge into a sump. Provision was made for
venting the footing drains and sub-slab to the outside in two locations.
Combustion appliances in the basement include a gas-fired domestic water heater and gas-
fired forced-air furnace.
Installed Mitigation Techniques
Table 4.12-2 summarizes the mitigation techniques tested in this house. Figure 4.12-2 shows
continuous radon measurement results during Phases 0 to 3. Table 4.12-3 summarizes the integrated
radon concentrations for each of the monitoring periods indicated.
Discussion of Results
When radon was first measured in this house with charcoal canisters in mid-December, 1988,
the passive sub-slab ventilation system was in place (Phase 2). Radon levels were 18.7 pCi/L in the
basement, 17.8 pCi/L on the first floor, and 12.6 pCi/L on the second floor (see Table 4.12-3). When
radon was measured in the basement with a continuous radon monitor, in February 1989, radon levels
had dropped to a three-day average of 6.5 pCi/L (see Figure 4.12-2). There is no explanation for this
variation, except for possible differences in weather conditions between the two periods. When the
passive vents were capped (Phase 1), radon levels increased slightly (but not significantly) to 8.0
pCi/L. Radon levels remained essentially unchanged at 7.8 pCi/L when radon was directly vented into
the basement (Phase 0). Apparently, radon has enough freedom to enter the basement from beneath
the foundation (especially the walls) that venting the sub-slab into the basement (Phase 0), or the
outside (Phase 2), or blocking off the ventilation (Phase 1) has little effect on indoor radon levels.
On the other hand, when a fan was attached to the vent to create active sub-slab
depressurization (Phase 3) there was a dramatic drop in integrated continuous radon levels to 1.5
pCi/L (see Figure 4.13-2). Phase 3 charcoal canister results in the basement and on the first and
4.12-1
-------
second floors were 1.7 pCi/L, 1.3 pCi/L, and 1.8 pCi/L, respectively (see Table 4.12-3).
4.12-2
-------
TABLE 4.12-1. HOUSE ON-11
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1988
PUBLIC
FOUNDATION STRUCTURE: WALK-OUT BASEMENT
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
6 FEET (1.8 METERS)
CONCRETE BLOCK WITH TERMITE
BLOCKS AT GRADE LEVEL
MISSING TERMITE BLOCKS, OPEN
PILASTERS
BARE CONCRETE OVER PLASTIC FILM
NONE
CRUSHED STONE
INTERIOR COMPLETE LOOP TO
VENTED SUMP
UPSTAIRS AND OUTSIDE
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.12-3
-------
HOLLOW CONCRETE BLOCK WALLS WfTH TERMfTE BLOCKS AT GRADE LEVEL
K)
OARAGE (OUADE LEVEI)
• PASSIVE VENT TO INSIDE (PI IASE 0)
PASSIVE VENT CAPPED (PHASES I & 3)
PASSIVE VENT TO OUTSIDE (PHASE 2)
PASSWE VENT TO INSIDE (PHASE 0)
PASSIVE VENT CAPPED (PHASE 1)
PASSIVE VENT TO OUTSIDE (PHASE 2)
ACTIVE VENT TO OUTSIDE (PHASE 3)
FURNACE
OWN
APPROXIMATE SCALE 1/8 INCH = 1 FOOT
Figure 4.12-1. Houso ON-11 foundation floor plan
-------
TABLE 4.12-2. HOUSE ON-11
INSTALLED MITIGATION TECHNIQUES
PHASE 0 BASELINE RADON-RESISTANT CONSTRUCTION:
INSTALL CONTINUOUS AIRTIGHT POLYETHYLENE FILM OVER
AGGREGATE BEFORE SLAB IS POURED TO FOUNDATION WALL.
• ADHERE PLASTIC FILM TO TOP OF FOOTINGS AND FOUNDATION
WALLS WITH BITUMINOUS ROOFING CEMENT.
• TOOL PERIMETER EDGE OF SLAB AND FILL WITH URETHANE
CAULK.
INSTALL CONTINUOUS LAYER OF PORTLAND CEMENT WITH BITUMI-
NOUS COATING AROUND EXTERIOR FOUNDATION WALL AND FOOTING.
INSTALL COURSE OF TERMITE BLOCKS AT GRADE LEVEL.
INSTALL INTERIOR FOOTING DRAINS (WHICH DISCHARGE INTO
AIR-TIGHT SUMP) IN BASEMENT. PROVIDE FOR VENTING FOOTING
DRAINS AND SUB-SLAB IN TWO LOCATIONS. FOR PHASE 0, VENT
SUB-SLAB INTO BASEMENT.
PHASE 1 SEAL BELOW-GRADE OPENINGS AND CAP TWO VENTS.
PHASE 2 SEAL BELOW-GRADE OPENINGS AND PASSIVELY VENT BASEMENT
SUB-SLAB TO OUTSIDE USING TWO VENTS AT RIM JOIST.
PHASE 3 SEAL BELOW-GRADE OPENINGS, CAP ONE VENT, AND ACTIVELY
DEPRESSURIZE BASEMENT SUB-SLAB USING SECOND VENT.
4.12-5
-------
25 -i
O
o
O.
O
I
Z
UJ
O
Z
o
o
Z
o
Q
ID
UJ
CD
20 -
15 -
10 -
0
PHASE 0 - BASELINE
PHASE 1 - SEAL
PHASE 2 - SEAL, VENT SUB-SLAB
PHASE 3 - SEAL, DEPRESSUHIZE SUB-SLAB
PIIASE1 AVG. O.OpCI/1
PHASE 0 AVG. 7.8 pO/1
PIIASE2AVG.6.5pCI/1
I
T
2/3/09 2/4/09 2/5/09 2/6/09 2/7/09 2/0/09 2/9/09 2/10/09 2/11/09 2/12/09
DATE (mm/dd/yy)
Flguro 4.12-2. Houso ON-11 radon concentrations: phaso 0, phaso 1, phaso 2, and phaso 3
-------
TABLE 4.12-3. HOUSE ON-11
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION fDCi/T,l
MONITORING
PHASE DETECTOR* PERIOD
2 CC
2 CR
1 CR
0 CR
3 CR
3 CC
12/14/88
02/03/89
02/06/89
02/08/89
02/10/89
02/10/89
- 12/17/88
- 02/06/89
- 02/08/89
- 02/10/89
- 02/13/89
- 02/13/89
BASEMENT
18
6
8
7
1
1
.7
.5
.0
.8
.5
.7
FIRST SECOND
FLOOR FLOOR
17.8 12.6
-
-
-
-
1.3 1.8
*CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
4.12-7
-------
4.13 HOUSE ON-12
Description
Table 4.13-1 summarizes the characteristics of house ON-12. Figure 4.13-1 shows the
foundation floor plan. The house is a single-family colonial with a walk-out basement and an
attached garage at ground level. The house was built in 1989 in the same subdivision as test houses
ON-09, ON-10, ON-11, ON-13, ON-14, ON-15, ON-16, and control houses ON-04 and ON-05. The
bedrock, which is near the surface, is highly fractured Onondaga Limestone. The walk-out basement
at the back of the house has a sub-foundation, excavated well below the level of the basement slab.
Hollow-core concrete blocks, with termite blocks at grade level, were used to build the foundation
walls. A complete loop of interior footing drains discharge into a sump. Provision was made for
venting the footing drains and sub-slab to the outside in two locations.
Combustion appliances in the basement include a gas-fired domestic water heater and gas-
fired forced-air furnace.
Installed Mitigation Techniques
Table 4.13-2 summarizes the mitigation techniques tested in this house. Figures 4.13-2,4.13-3,
and 4.13-4 show continuous radon measurement results during Phases 0 to 3. Table 4.13-3
summarizes the integrated radon concentrations for each of the monitoring periods indicated.
Discussion of Results
Continuous radon measurements were performed in this house from mid-March, 1989 to May
24,1989 (see Figures 4.13-2, 4.13-3, and 4.13-4). With the house closed and radon allowed to vent
directly into the basement (Phase 0), average radon concentrations were 4.4 pCi/L. During a second
period, from March 28, 1989 to April 2, radon levels were slightly lower, especially when the vents
were closed. However, this was also at a time when there was extensive interior painting of walls and
floors which required opening the windows. Therefore, during this period the radon measurements
were not performed under closed house conditions (see Figure 14.13-3). From May 7, 1989 to May
23, 1989 the interior of the house was essentially complete and the house closed. Radon levels
measured during each of the Phases 0, 1, and 2 remained virtually unchanged (see Figure 14.13-4),
indicating for this house that radon entry into the basement was unaffected by venting the sub-slab
into the basement (Phase 0), venting the sub-slab to the outside (Phase 2), or blocking the sub-slab
vent (Phase 1).
However, during Phase 3, when one of the vents was used to provide sub-slab
depressurization and the other vent capped, integrated continuous radon levels were significantly
4.13-1
-------
reduced to 2.1 pCi/L (see Figure 4.13-4). Phase 3 charcoal canister results in the basement and on
the second floor were 1.5 pCi/L and 1.2 pCi/L, respectively (see Table 4.13-3).
4.13-2
-------
TABLE 4.13-1. HOUSE ON-12
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1989
PUBLIC
FOUNDATION STRUCTURE: WALK-OUT FULL BASEMENT
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
4 FEET (1.2 METERS)
CONCRETE BLOCK WITH TERMITE
BLOCKS AT GRADE LEVEL
NONE
BARE CONCRETE OVER PLASTIC FILM
NONE
CRUSHED STONE
INTERIOR COMPLETE LOOP TO
VENTED SUMP
UPSTAIRS AND OUTSIDE
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.13-3
-------
HOLLOW CONCflETE DLOCK WALLS WfTH TERMfTE BLOCKS AT GRADE LEVEL
t>
_i
O3
OAHAOE (OIWDE LEVEL)
FU1NACE
PASSIVE VENT TO INSIDE (PI IASE 0)
PASSIVE VENT CAPPED (PHASE 1 » 3)
PASSIVE VENT TO OUTSIDE (PHASE 2)
PASSIVE VENT TO IN SIDE (PHASE 0)
PASSWE VENT CAPPED (P»iAS6 1)
PASSIVE VENT TO OUTSIDE (PHASE ?)
ACTIVE VEMT TO OUTSIDe (HIASE 3)
APPROXIMATE SCALE 1/8 INCH = 1 FOOT
Figure 4.13-1. House ON-12 toundatlon lloor plan
-------
TABLE 4.13-2. HOUSE ON-12
INSTALLED MITIGATION TECHNIQUES
PHASE 0 - BASELINE RADON-RESISTANT CONSTRUCTION:
INSTALL CONTINUOUS AIRTIGHT POLYETHYLENE FILM OVER
AGGREGATE BEFORE SLAB IS POURED TO FOUNDATION WALL.
• ADHERE PLASTIC FILM TO TOP OF FOOTINGS AND FOUNDATION
WALLS WITH BITUMINOUS ROOFING CEMENT.
• TOOL PERIMETER EDGE OF SLAB AND FILL WITH URETHANE
CAULK
INSTALL CONTINUOUS LAYER OF PORTLAND CEMENT WITH BITUMI-
NOUS COATING AROUND EXTERIOR FOUNDATION WALL AND FOOTING.
INSTALL COURSE OF TERMITE BLOCKS AT GRADE LEVEL.
INSTALL INTERIOR FOOTING DRAINS (WHICH DISCHARGE INTO
AIR-TIGHT SUMP) IN BASEMENT. PROVIDE FOR VENTING FOOTING
DRAINS AND SUB-SLAB IN TWO LOCATIONS. FOR PHASE 0, VENT
SUB-SLAB INTO BASEMENT.
PHASE 1 - SEAL BELOW-GRADE OPENINGS AND CAP TWO VENTS.
PHASE 2 - SEAL BELOW-GRADE OPENINGS AND PASSIVELY VENT BASEMENT
SUB-SLAB TO OUTSIDE USING TWO VENTS AT RIM JOIST.
PHASE 3 - SEAL BELOW-GRADE OPENINGS, CAP ONE VENT, AND ACTIVELY
DEPRESSURIZE BASEMENT SUB-SLAB USING SECOND VENT.
4.13-5
-------
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10
5 -
0 -
PHASED-BASELINE
PIIASEOAVG. 4.4pCi/l
T
3/21/89
3/22/89
3/23/89 3/24/89
DATE (mm/dd/yy)
Figure 4.13-2. Houso ON-12 radon concentrations: phase 0
3/25/89
3/26/89
-------
25 -i
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PHASE 0 - BASELINE
PHASE 1 - SEAL
PHASE 0 MG. 3.4 pCi/1
PHASE 1 MG. 1.4pCI/l
0 -
II'1
3/29/89 3/30/89 3/31/89 4/01/89 4/02/89
DATE (mm/dd/yy)
Figure 4.13-3. Mouse ON-12 radon concentrations: phase 0 and phase 1
4/03/89
4/04/89
-------
25
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c- 20 -
o
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10
5 ~
0
PHASE 0 - BASELINE
PHASE 1 - SEAL
PI IASE 2 - SEAL, VENT SUB-SLAB
PHASE 3 - SEAL. DEPRESSURIZE SUB-SLAB
PHASE 1 AVG. 4.3pCI/l
PHASE OAVG. 4.2 pCi/l
PIIASE2AVG. 4.4pCW
PHASE 3 AVG. 2.1 pCI/1
! 1 1 1 1 1 1 1 1 I I I I I I I I
4/07/09 4/09/89 4/11/09 4/13/09 4/15/09 4/17/09 4/19/09 4/21/89 4/23/89
4/00/89 4/10/89 4/12/09 4/14/09 4/16/09 4/18/89 4/20/89 4/22/89
DATE (mm/dd/yy)
Figure 4.13-4. Houso ON-12 radon concentrations: phase 0, phaso 1, phase 2, and phase 3
-------
TABLE 4.13-3. HOUSE ON-12
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (DCi/L)
MONITORING
PHASE DETECTOR* PERIOD
0 CR
0 CR
1** CR
0 CR
1 CR
2 CR
3 CR
3 CC
03/21/89
03/28/89
04/02/89
04/06/89
04/10/89
04/12/89
04/21/89
04/21/89
- 03/26/89
- 04/02/89
- 04/04/89
- 04/10/89
- 04/12/89
- 04/21/89
- 04/24/89
- 04/24/89
BASEMENT
4.4
3.4
1.4
4.2
4.3
4.4
2.1
1.5
FIRST SECOND
FLOOR FLOOR
- -
- -
- -
- -
- -
- -
1.2
*CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
**WINDOWS OPEN
4.13-9
-------
4.14 HOUSE ON-13
Description
Table 4.14-1 summarizes the characteristics of house ON-13. Figure 4.14-1 shows the
foundation floor plan. The house is a single-family colonial with a walk-out basement, small crawl
space, and attached garage at ground level. The house was built in 1989 in the same subdivision as
test houses ON-09, ON-10, ON-11, ON-12, ON-14, ON-15, ON-16, and control houses ON-04 and
ON-05. The bedrock, which is near the surface, is highly fractured Onondaga Limestone. The walk-
out basement at the back of the house has a sub-foundation, excavated well below the level of the
basement slab. Hollow-core concrete blocks, with termite blocks at grade level, were used to build
the foundation walls. A complete loop of interior footing drains discharge into a sump. Provisions
were made in three locations for venting the footing drains and sub-slab to the outside.
Combustion appliances in the basement include a gas-fired domestic water heater and gas-
fired forced-air furnace.
Installed Mitigation Techniques
Table 4.14-2 summarizes the mitigation techniques tested in this house. Figures 4.14-2, 4.13-3
show continuous radon measurement results during Phases 0 to 3. Table 4.14-3 summarizes the
integrated radon concentrations for each of the monitoring periods indicated.
Discussion of Results
Continuous radon measurements were performed in house ON-13 during January 1989 while
the house interior was still being completed, and again in mid-March after the house was closed and
unoccupied. The March measurements indicate four distinct plateaus corresponding to the four
different phases. The relative magnitudes of the radon concentrations of each phase are as expected:
Phase 0 is the highest level at 18.1 pCi/L, Phase 1 is next with 13.1 pCi/L, Phase 2 is next with 9.6
pCi/L and Phase 3 is the lowest with 1.7 pCi/L. Although the passive techniques in this house,
demonstrated in Phase 1 and Phase 2, provided reductions in radon levels, only active sub-slab
deprcssurization reduced radon levels below the 4 pCi/L guideline. Basement radon levels during
Phase 3 were 1.7 pCi/L from a continuous monitor and 1.8 pCi/L from a charcoal canister. Phase
3 charcoal canister results on the first and second floors were 1.1 pCi/L and 1.5 pCi/L, respectively
(sec Table 4.14-3).
4.14-1
-------
TABLE 4.14-1. HOUSE ON-13
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1989
PUBLIC
FOUNDATION STRUCTURE: WALK-OUT FULL BASEMENT
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
4 FEET (1.2 METERS)
CONCRETE BLOCK WITH TERMITE
BLOCKS AT GRADE LEVEL
NONE
BARE CONCRETE OVER PLASTIC FILM
NONE
CRUSHED STONE
INTERIOR COMPLETE LOOP TO
VENTED SUMP
UPSTAIRS AND OUTSIDE
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.14-2
-------
0 PASSIVE VENT TO INSIDE (PHASED)
PA5KIVE VCNF CAPPU) (PHASES I 4 3)
PASSIVE VENI TOOUISIl)E(PHASE2)
IIOLLOW CONCnETE QLOCK WALLS WfTI I TERMfTE BLOCKS AT GRADE LEVEL
PASSIVE VENT TO INSIDE (PHASE 0) ,
PASSIVE VENT CAPPED (PHASES I & 3)
PASSrVE VENT TO OUTSIDE (PI IASE 2)
CIIAWL SPACE
OAIIAOE (OHADE LEVEL)
PASSfVE Vf NT TO INSIDE (PI IASE 0)
PASSIVE VENT CAPPED (PHASE 1)
PASSIVE VENT TO OUTSIOE (PHASE 2)
ACTIVE VENT TO OUT SIDE (PI IASE 3)
APPROXIMATE SCALE 1/8 INCH => 1 FOOT
Figure 1.14-1. House ON-13 foundation floor plan
-------
TABLE 4.14-2. HOUSE ON-13
INSTALLED MITIGATION TECHNIQUES
PHASE 0 - BASELINE RADON-RESISTANT CONSTRUCTION:
INSTALL CONTINUOUS AIRTIGHT POLYETHYLENE FILM OVER
AGGREGATE BEFORE SLAB IS POURED TO FOUNDATION WALL.
• ADHERE PLASTIC FILM TO TOP OF FOOTINGS AND FOUNDATION
WALLS WITH BITUMINOUS ROOFING CEMENT.
• TOOL PERIMETER EDGE OF SLAB AND FILL WITH URETHANE
CAULK.
INSTALL CONTINUOUS LAYER OF PORTLAND CEMENT WITH BITUMI-
NOUS COATING AROUND EXTERIOR FOUNDATION WALL AND FOOTING.
INSTALL COURSE OF TERMITE BLOCKS AT GRADE LEVEL.
INSTALL INTERIOR FOOTING DRAINS (WHICH DISCHARGE INTO
AIR-TIGHT SUMP) IN BASEMENT. PROVIDE FOR VENTING FOOTING
DRAINS AND SUB-SLAB IN THREE LOCATIONS. FOR PHASE 0, VENT
SUB-SLAB INTO BASEMENT.
PHASE 1 - SEAL BELOW-GRADE OPENINGS AND CAP THREE VENTS.
PHASE 2 - SEAL BELOW-GRADE OPENINGS AND PASSIVELY VENT BASEMENT
SUB-SLAB TO OUTSIDE USING TWO VENTS AT RIM JOIST.
PHASE 3 - SEAL BELOW-GRADE OPENINGS, CAP TWO VENTS, AND ACTIVELY
DEPRESSURIZE BASEMENT SUB-SLABS USING THIRD VENT.
4.14-4
-------
25
20
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UJ
CO
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co
15
10 -
5 -
0 -L
I IASII 0 - BASELINE
PHASED AVG. 12.0pCi/l
EPA GUIDELINE {4 pCi/1)
1/27/09
1/20/09
1/29/09
DATE (mm/dd/yy)
Figure 4.14-2. llouso ON-13 radon concenlrallons: phase 0
-------
25 -
Ji.
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20 -
15
10
5 -
0
PI IASE 0 - BASELINE
PI IASE 1 - SEAL
PI IASE 2 - SEAL, VENT SUB-SLAB
PI IASE 3 - SEAL, DEPRESSURIZE SUB-SLAB
PHASE 1 AVG. 13.1 pCI/l
PHASE OAVG. 18.1 pCl/1
PI IASE 2 AVG. 9.6pCi/l
T
T
T
3/7/09 3/8/89 3/9/09 3/10/89 3/11/09 3/12/09 3/13/09 3/14/89 3/15/89
DATE (mm/dd/yy)
Figure 4.14-3. Houso ON-13 radon concentrations: phase 0, phase 1, phase 2, and phase 3
-------
TABLE 4.14-3. HOUSE ON-13
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION fnCi/T,^
MONITORING
PHASE DETECTOR* PERIOD
0 CR
2 CR
1 CR
0 CR
3 CR
3 CC
01/27/89
03/07/89
03/10/89
03/11/89
03/13/89
03/13/89
- 01/30/89
- 03/09/89
- 03/11/89
- 03/13/89
- 03/16/89
- 03/16/89
BASEMENT
12
9
13
18
1
1
.8
.6
.1
.1
.7
.8
FIRST SECOND
FLOOR FLOOR
.
-
-
-
-
1.1 1.5
'CC - CHARCOAL CANISTER, CR = CONTINUOUS RADON
4.14-7
-------
4.15 HOUSE ON-14
Description
Table 4.15-1 summarizes the characteristics of house ON-14. Figure 4.15-1 shows the
foundation floor plan. The house is a single-family colonial with a basement and attached garage
at ground level. The house was built in 1988 in the same subdivision as test houses ON-09, ON-10,
ON-11, ON-12, ON-13, ON-15, ON-16, and control houses ON-04 and ON-05. The bedrock, which
is near the surface, is highly fractured Onondaga Limestone. The walk-out basement at the back of
the house has a sub-foundation, excavated well below the level of the basement slab. Hollow-core
concrete blocks, with termite blocks at grade level, were used to build the foundation walls. A
complete loop of interior footing drains discharge into a sump. Provisions were made in one location
for venting the footing drains and sub-slab to the outside.
Combustion appliances in the basement include a gas-fired domestic water heater and gas-
fired forced-air furnace.
Installed Mitigation Techniques
Table 4.15-2 summarizes the mitigation techniques tested in this house. Table 4.15-3
summarizes the integrated radon concentrations for each of the monitoring periods indicated.
Discussion of Results
Charcoal canister measurements of radon, taken at the end of December 1988, were well
below the 4 pCi/L guideline (see Table 4.15-3). Radon levels in the basement were 1.9 pCi/L , on
the first floor were 1.3 pCi/L, and on the second floor were 1.3 pCi/L. No follow-up measurements
were taken in this house because of the low initial measurements.
Although this house was built in an area where highly fractured Onondaga Limestone is often
found just below the surface, the basement was excavated in a hollow area to firm ground and
transported dirt from a distant site was used as backfill. This fact, more than the basement
construction, probably accounts for the low radon levels.
4.15-1
-------
TABLE 4.15-1. HOUSE ON-14
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1988
PUBLIC
FOUNDATION STRUCTURE: WALK-OUT FULL BASEMENT
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
4 FEET (1.2 METERS)
CONCRETE BLOCK WITH TERMITE
BLOCKS AT GRADE LEVEL
NONE
BARE CONCRETE OVER PLASTIC FILM
NONE
CRUSHED STONE
INTERIOR COMPLETE LOOP TO
VENTED SUMP
UPSTAIRS AND OUTSIDE
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.15-2
-------
HOLLOW CONCRETE BLOCK WALLS WfTH TERMITE BLOCKS AT GRADE LEVEL
Ul
(.0
OARAGE (onADT:LEVEL)
PASSIVE VENT TO OUTSIDE
APPROXIMATE SCALE 1/8 INCH = 1 FOOT
Figure 4.15-1. House ON-14 foundation floor plan
-------
TABLE 4.15-2. HOUSE ON-14
INSTALLED MITIGATION TECHNIQUES
PHASE 0 - BASELINE RADON-RESISTANT CONSTRUCTION:
INSTALL CONTINUOUS AIRTIGHT POLYETHYLENE FILM OVER
AGGREGATE BEFORE SLAB IS POURED TO FOUNDATION WALL.
• ADHERE PLASTIC FILM TO TOP OF FOOTINGS AND FOUNDATION
WALLS WITH BITUMINOUS ROOFING CEMENT.
• TOOL PERIMETER EDGE OF SLAB AND FILL WITH POLYURE-
THANE CAULK
INSTALL CONTINUOUS LAYER OF PORTLAND CEMENT WITH BITUMI-
NOUS COATING AROUND EXTERIOR FOUNDATION WALL AND FOOTING.
INSTALL COURSE OF TERMITE BLOCKS AT GRADE LEVEL.
INSTALL INTERIOR FOOTING DRAINS (WHICH DISCHARGE INTO
AIRTIGHT SUMP) IN BASEMENT. PROVIDE FOR VENTING FOOTING
DRAINS AND SUB-SLAB IN ONE LOCATION. FOR PHASE 0, VENT
SUB-SLAB INTO BASEMENT.
PHASE 1 SEAL BELOW-GRADE OPENINGS AND CAP VENT.
PHASE 2 - SEAL BELOW-GRADE OPENINGS AND PASSIVELY VENT BASEMENT
SUB-SLAB TO OUTSIDE USING ONE VENT AT RIM JOIST.
PHASE 3 SEAL BELOW-GRADE OPENINGS AND ACTIVELY DEPRESSURIZE
BASEMENT SUB-SLAB USING VENT.
4.15-4
-------
TABLE 4.15-3. HOUSE ON-14
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION fpCi/L)
PHASE
DETECTOR*
MONITORING
PERIOD
BASEMENT
FIRST
FLOOR
SECOND
FLOOR
CC
12/28/88 - 12/31/88
1.9
1.3
1.3
*CC = CHARCOAL CANISTER
4.15-5
-------
4.16 HOUSE ON-15
Description
Table 4.16-1 summarizes the characteristics of house ON-15. Figure 4.16-1 shows the
foundation floor plan. The house is a single-family colonial with a walk-out basement and attached
garage at ground level. The house was built in 1988 in the same subdivision as test houses ON-09,
ON-10, ON-11, ON-12, ON-13, ON-14, ON-16, and control houses ON-04 and ON-05. The bedrock,
which is near the surface, is highly fractured Onondaga Limestone. The walk-out basement at the
back of the house has a sub-foundation, excavated well below the level of the basement slab. Hollow-
core concrete blocks, with termite blocks at grade level, were used to build the foundation walls. A
complete loop of interior footing drains discharge into a sump. Provisions were made in two locations
for venting the footing drains and sub-slab to the outside.
Combustion appliances in the basement include a gas-fired domestic water heater and gas-
fired forced-air furnace.
Installed Mitigation Techniques
Table 4.16-2 summarizes the mitigation techniques tested in this house. Figures 4.16-2,4.16-3,
and 4.16-4 show continuous radon measurement results during Phases 0 to 3. Table 4.16-3
summarizes the integrated radon concentrations for each of the monitoring periods indicated.
Discussion of Results
Charcoal canister measurements in house ON-15 during January 1989 indicated radon levels
just above the 4 pCi/L guideline in the basement (5.7 pCi/L) and just below the guideline on the first
and second floors (3.6 pCi/L and 3.9 pCi/L, respectively) during Phase 2 when the basement sub-slab
was vented to the outside (see Table 4.16-3). When continuous radon measurements were performed
just after this period, radon concentrations in the basement were 6.4 pCi/L with the sub-slab vent
open (Phase 2) and essentially the same (5.8 pCi/L) during Phase 1 when the vent was capped (see
Figures 4.16-2 and 4.16-3). As shown in Figure 4.16-4 a series of tests was performed in early
February 1989, in which there were essentially no changes in integrated continuous radon levels for
Phases 0, 1, and 2 (all close to 7.0 pCi/L). However, there was a dramatic drop once active sub-slab
depressurization was installed (Phase 3). Basement radon levels during Phase 3 were 1.9 pCi/L
according to a continuous monitor and 1.0 pCi/L according to a charcoal canister. Phase 3 charcoal
canister results on the first and second floors were 0.6 pCi/L and 1.3 pCi/L, respectively (see Table
4.16-3).
The masonry foundation work for this house was particularly well done. A sub-foundation
4.16-1
-------
structure was required to accommodate the foundation for the walk-out basement and provide a
stable footing for other parts of the foundation. At the basement slab level, a row of termite blocks
was installed and filled with mortar before the concrete block basement walls were constructed.
There appeared to be no major below-grade openings in the basement of this house.
4.16-2
-------
TABLE 4.16-1. HOUSE ON-15
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1988
PUBLIC
FOUNDATION STRUCTURE: WALK-OUT FULL BASEMENT
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
4 FEET (1.2 METERS)
CONCRETE BLOCK WITH TERMITE
BLOCKS AT GRADE LEVEL
NONE
BARE CONCRETE OVER PLASTIC FILM
NONE
CRUSHED STONE
INTERIOR COMPLETE LOOP TO
VENTED SUMP
UPSTAIRS AND OUTSIDE
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.16-3
-------
HOLLOW CONCRETE BLOCK WALLS WfTM TERMfTE BLOCKS AT GRADE LEVEL
A
_A
cn
9 PASSIVE VENT TO INSIDE (PI IASE 0)
I'ASSIVE VENr CAPPED fl'l IASES I & 3)
PASSIVE VEMf TO OlirSIDE (PHASE 2)
PASSIVE VENT TO INSIDE (PI IASE 0)
PASSIVE VENT CAPPED (PHASE 1)
PASSIVE VENT TO OUTSIDE (P» IASE 2)
ACTIVE VENT TO OUTSIDE (PHASE 3)
OARAGE (GRADE LEVEL)
APPROXIMATE SCALE 1/8 INCH = 1 FOOT
Figure 4.1G-1. House ON-15 foundation floor plan
-------
TABLE 4.16-2. HOUSE ON-15
INSTALLED MITIGATION TECHNIQUES
PHASE 0 BASELINE RADON-RESISTANT CONSTRUCTION:
INSTALL CONTINUOUS AIRTIGHT POLYETHYLENE FILM OVER
AGGREGATE BEFORE SLAB IS POURED TO FOUNDATION WALL.
• ADHERE PLASTIC FILM TO TOP OF FOOTINGS AND FOUNDATION
WALLS WITH BITUMINOUS ROOFING CEMENT.
• TOOL PERIMETER EDGE OF SLAB AND FILL WITH URETHANE
CAULK
INSTALL CONTINUOUS LAYER OF PORTLAND CEMENT WITH BITUMI-
NOUS COATING AROUND EXTERIOR FOUNDATION WALL AND FOOTING.
INSTALL COURSE OF TERMITE BLOCKS AT GRADE LEVEL.
INSTALL INTERIOR FOOTING DRAINS (WHICH DISCHARGE INTO
AIR-TIGHT SUMP) IN BASEMENT. PROVIDE FOR VENTING FOOTING
DRAINS AND SUB-SLAB IN TWO LOCATIONS. FOR PHASE 0, VENT
SUB-SLAB INTO BASEMENT.
PHASE 1 SEAL BELOW-GRADE OPENINGS AND CAP TWO VENTS.
PHASE 2 - SEAL BELOW-GRADE OPENINGS AND PASSIVELY VENT BASEMENT
SUB-SLAB TO OUTSIDE USING TWO VENTS AT RIM JOIST.
PHASE 3 SEAL BELOW-GRADE OPENINGS, CAP ONE VENT, AND ACTIVELY
DEPRESSURIZE BASEMENT AND SUB-SLAB USING SECOND VENT.
4.16-5
-------
o
25
20
O
a.
Z
O
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uu
o
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o
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15
10
5 -
0 -
PI IASE 2 - SEAL, VENT SUB-SLAB
PHASE 2 AVG. 6.-1 pCi/l
A
v v
EPA GUIDELINE (-1 pCI/1)
1/5/09
1/6/09
1/7/89
DATE (mm/dd/yy)
Figure 4.16-2. House ON-15 radon concentrallons: phase 2
A-
1/8/09
-------
ffl
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o
CL
Z
O
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o
z
O
O
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LU
111
3
25
20 -
15 -
10 -
5 -
PI IASE 1 - SEAL
PHASE! AVG. 5.0 pCi/1
EPA.GUIDELINE.^ pC(/l)
1
1/17/89
1/18/09
1/19/89 1/20/89
DATE (mm/dd/yy)
I
1/21/89
Figure 4.16-3. Mouse ON-15 radon concentrations: phase 1
-------
25
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CD
20 -
15 -
10 -
5 -
0
PHASE 0 - BASELINE
PHASE 1 - SEAL
PHASE 2 - SEAL, VENT SUB-SLAB
PHASE 3 - SEAL, DEPRESSURIZE SUB-SLAB
PHASE 2 AVG. 7.1 pCI/1 p| IASE 2 AVG. 6.9 pCi/l
PIIASE1 AVG.7.0pCi/l
PHASED AVG. 7.2 pCi/l
PHASE 3 AVG. 1.9pCI/l
1 1 1 1 I 1 I I I I I 1—
2/1/89 2/2/89 2/3/89 2/4/89 2/5/89 2/6/89 2/7/89 2/8/89 2/9/89 2/10/89 2/11/89 2/12/89
DATE (mm/dd/yy)
Figure 4.16-1. Mouse ON-15 radon concentrations: phase 0, phase 1, phase 2, and phase 3
-------
TABLE 4.16-3. HOUSE ON-15
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (pCi/L^
MONITORING
PHASE DETECTOR* PERIOD
2 CC
2 CR
1 CR
2 CR
1 CR
2 CR
0 CR
3 CR
3 CC
01/03/89
01/05/89
01/17/89
02/01/89
02/03/89
02/06/89
02/07/89
02/10/89
02/10/89
- 01/06/89
- 01/09/89
- 01/22/89
- 02/03/89
- 02/06/89
- 02/07/89
- 02/10/89
- 02/13/89
- 02/13/89
BASEMENT
5.7
6.4
5.8
7.4
7.0
6.9
7.2
1.9
1.0
FIRST SECOND
FLOOR FLOOR
3.6 3.9
-
-
-
-
-
-
-
0.6 1.3
*CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
4.16-9
-------
4.17 HOUSE ON-16
Description
Table 4.17-1 summarizes the characteristics of house ON-16. Figure 4.17-1 shows the
foundation floor plan. The house is a single-family colonial with a walk-out basement, small crawl
space, and attached garage at ground level. The house was built in 1988 in the same subdivision as
test houses ON-09 through ON-15, and control houses ON-04 and ON-05. This house was nearly
identical in construction including the walk-out basement, the hollow-core concrete blocks, with
termite blocks at grade level, and the complete loop of interior footing drains discharged into a sump.
Provisions were made for venting the footing drains and sub-slab to the outside in two locations.
Combustion appliances in the basement include a gas-fired domestic water heater and gas-
fired forced-air furnace.
Installed Mitigation Techniques
Table 4.17-2 summarizes the mitigation techniques tested in this house. Figures 4.17-2 and
4.17-3 show continuous radon measurement results during Phases 0 to 3. Table 4.17-3 summarizes
the integrated radon concentrations for each of the monitoring periods indicated.
Discussion of Results
Charcoal canister measurements were made in house ON-16 during December 1988, while
the sub-slab was passively vented (Phase 2). The results of these measurements were 13.7 pCi/L in
the basement, 10.0 pCi/L on the first floor, and 10.7 pCi/L on the second floor (see Table 4.17-3).
Continuous radon measurements in the basement during January 1989 indicated basement radon
levels of 14.0 pCi/L, consistent with the charcoal canister results. When the sub-slab vents were
allowed to vent into the basement (Phase 0), radon levels rose to an average of 25.0 pCi/L.
Reduction below 4pCi/L was accomplished by actively depressurizing the sub-slab during Phase 3,
reducing integrated continuous radon levels to 1.6 pCi/L in the basement (see Figure 4.17-3).
Charcoal canister measurements during Phase 3 indicated 1.6 pCi/L in the basement, 1.1 pCi/L on
the first floor, and 1.4 pCi/L on the second floor.
4.17-1
-------
4.1 Y-l. tlUUSU Ul\-10
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1988
PUBLIC
FOUNDATION STRUCTURE: 80% BASEMENT, 20% CRAWL SPACE
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
6 FEET (1.8 METERS)
CONCRETE BLOCK WITH TERMITE
BLOCKS AT GRADE LEVEL
MISSING TERMITE BLOCKS
BARE CONCRETE OVER PLASTIC FILM
FLOOR CRACKS
CRUSHED STONE
INTERIOR COMPLETE LOOP TO
VENTED SUMP
UPSTAIRS AND OUTSIDE
AVERAGE HEIGHT OF CRAWL SPACE:
CRAWL SPACE WALLS:
CRAWL SPACE FLOOR SURFACE:
CRAWL SPACE VENTILATION:
CRAWL SPACE INSULTATION:
ACCESS TO CRAWL SPACE:
4 FEET (1.2 METERS)
CONCRETE BLOCK WITH TERMITE
BLOCKS AT GRADE LEVEL
BARE CONCRETE OVER PLASTIC FILM
AND CRUSHED STONE
NONE
EXTERIOR WALLS
UPSTAIRS
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.17-2
-------
PASSIVE VENT TO INSIDE (PI tASE 0)
PASSIVE VENT TO OUTSIDE (PI IASE 2)
ACTIVE VENT TO OUTSIDE (PHASE 3)
IIOLLOW CONCRETE BLOCK WALLS WfTH TERMITE BLOCKS AT GRADE LEVEL
SUOSLAO CONNECTION PIPE TO CfWVfl. SPACE
PASSIVE VENT TO INSIDE (PI IASE 0)
PASSIVE VENT CAPPED (PHASE 3)
PASSIVE VENT TO OUTSIDE (PI IASE 2)
CHAWL SPACE
OAnAQE (ORADE LEVEL)
APPROXIMATE SCALE 1/8 INCH » 1 FOOT
Figure 4.17-1. House ON-16 foundation floor plan
-------
TABLE 4.17-2. HOUSE ON-16
INSTALLED MITIGATION TECHNIQUES
PHASE 0 - BASELINE RADON-RESISTANT CONSTRUCTION:
INSTALL CONTINUOUS AIRTIGHT POLYETHYLENE FILM OVER
AGGREGATE BEFORE SLAB IS POURED TO FOUNDATION WALL.
• ADHERE PLASTIC FILM TO TOP OF FOOTINGS AND FOUNDATION
WALLS WITH BITUMINOUS ROOFING CEMENT.
• TOOL PERIMETER EDGE OF SLAB AND FILL WITH POLYURE-
THANE CAULK
INSTALL CONTINUOUS LAYER OF PORTLAND CEMENT WITH BITUMI-
NOUS COATING AROUND EXTERIOR FOUNDATION WALL AND FOOTING.
INSTALL COURSE OF TERMITE BLOCKS AT GRADE LEVEL.
INSTALL INTERIOR FOOTING DRAINS (WHICH DISCHARGE INTO
AIR-TIGHT SUMP) IN BASEMENT AND CRAWL SPACE. PROVIDE FOR
VENTING FOOTING DRAINS AND SUB-SLAB IN TWO LOCATIONS.
FOR PHASE 0, VENT SUB-SLABS INTO BASEMENT.
PHASE 1 - SEAL BELOW-GRADE OPENINGS AND CAP TWO VENTS.
PHASE 2 SEAL BELOW-GRADE OPENINGS AND PASSIVELY VENT BASEMENT
SUB-SLAB TO OUTSIDE USING TWO VENTS AT RIM JOIST.
PHASE 3 SEAL BELOW-GRADE OPENINGS, CAP ONE VENT, AND ACTIVELY
DEPRESSURIZE BASEMENT AND CRAWL SPACE SUB-SLABS USING
SECOND VENT.
4.17-4
-------
(/I
00
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20 -
0
PHASE 2 - SEAL, VENT SUB-SLAB
EPA GUIDELINE (1 pCI/l)
1/17/09
1/10/09
I
1/19/09
PMASE2AVG. H.OpCi/l
I I
1/20/09 1/21/09
DATE (mm/dd/yy)
I
1/22/09
I
1/23/09
Figure 4.17-2. House ON-16 radon conconlrpllons: phase 2
-------
80 -
o 60 ~
a.
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20 -
0 -
PHASED-BASELINE
PHASE 3 - SEAL, DEPRESSURIZE SUB-SLAB
PIIASEOAVG. 25.0pCi/l
EPA GUIDELINE (1 pC!/l)
PHASE3AVG. I.GpCi/I
1
. • I^KI-.^O^.——..tt.,*.^. .,
T
T
T
1/31/89 2/1/09 2/2/89 2/3/89 2/4/89 2/5/89
DATE (mm/dd/yy)
Figure 4.17-3. House ON-16 radon concentrations: phase 0 and phase 3
2/6/89
2/7/89
,
2/8/89
-------
TABLE 4.17-3. HOUSE ON-16
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (cCi/D
MONITORING
PHASE DETECTOR* PERIOD BASEMENT
2 CC
2 CR
0 CR
3 CR
3 CC
12/14/88
01/17/89
01/31/89
02/02/89
02/06/89
- 12/17/88 13.7
- 01/23/89 14.0
- 02/02/89 25.0
- 02/09/89 1.6
- 02/09/89 1.6
FIRST SECOND
FLOOR FLOOR
10.0 10.7
- -
-
-
1.1 1.4
*CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
4.17-7
-------
4.18 HOUSE ON-17
Description
Table 4.18-1 summarizes the characteristics of house ON-17. Figure 4.18-1 shows the
foundation floor plan. The house is a single-family colonial with a full basement, a crawl space, and
an attached garage at ground level. The house was built in 1988 in the same subdivision as control
houses ON-01 and ON-02. The bedrock, which is near the surface, is highly fractured Onondaga
Limestone. The foundation was excavated directly into the fractured bedrock and the bedrock debris
was used as backfill around the exterior of the foundation walls. Standard wall construction included
hollow-core concrete blocks with termite blocks at grade level. A complete loop of interior footing
drains discharge into a sump. The footing drains and sub-slab were vented to the outside from one
common location.
Combustion appliances in the basement include a gas-fired domestic water heater and gas-
fired forced-air furnace.
Installed Mitigation Techniques
Table 4.18-2 summarizes the mitigation techniques tested in this house. Figure 4.18-2 shows
continuous radon measurement results during Phases 0 to 3. Table 4.18-3 summarizes the integrated
radon concentrations for each of the monitoring periods.
Discussion of Results
Charcoal canister measurements were made in house ON-17 during February 1989, while the
sub-slab was passively vented to the outside (Phase 2). The results of these measurements were 7.6
pCi/L in the basement, 5.6 pCi/L on the first floor, and 4.6 pCi/L on the second floor (see Table 4.18-
3). Continuous radon measurements in the basement during the latter part of February and early
part of March indicated basement radon levels of 6.7 pCi/L for Phase 2, 7.7 pCi/L for Phase 0, and
8.1 pCi/L for Phase 1 (see Figure 4.18-2). Although passive venting of the sub-slab may have had
a marginal effect, the difference between venting the sub-slab into the basement and capping these
vents had no effect.
Basement radon levels dropped significantly under active depressurization (Phase 3) with
average continuous radon levels measured at 2.1 pCi/L (see Figure 4.18-2). Phase 3 charcoal canister
results in the basement, on the first floor, and on the second floor were 0.9 pCi/L, 0.6 pCi/L, and 0.8
pCi/L, respectively (see Table 4.18-3).
4.18-1
-------
TABLE 4.18-1. HOUSE ON-17
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1988
PUBLIC
FOUNDATION STRUCTURE: 80% BASEMENT, 20% CRAWL SPACE
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
6 FEET (1.8 METERS)
CONCRETE BLOCK WITH TERMITE
BLOCKS AT GRADE LEVEL
MISSING TERMITE BLOCKS
BARE CONCRETE OVER POLYURETHANE
NONE
CRUSHED STONE
INTERIOR COMPLETE LOOP TO
VENTED SUMP
UPSTAIRS AND OUTSIDE
AVERAGE HEIGHT OF CRAWL SPACE:
CRAWL SPACE WALLS:
CRAWL SPACE FLOOR SURFACE:
CRAWL SPACE VENTILATION:
CRAWL SPACE INSULTATION:
ACCESS TO CRAWL SPACE:
4 FEET (1.2 METERS)
CONCRETE BLOCK WITH TERMITE
BLOCKS AT GRADE LEVEL
BARE CONCRETE OVER POLYURETHANE
AND CRUSHED STONE
NONE
EXTERIOR WALLS
UPSTAIRS
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.18-2
-------
IIOLLOW CONCRETE BLOCK WALLS Win I TERMITE CLOCKS AT GRADE LEVEL
oo
CRAVrt. SPACE
OAI1AOE (GRADE LEVEL)
SUOSIAD CONNECTION PIPE TO CRAWL SPACE
FURNACE
PASSIVE VENT TO INSIDE (PI IASE 0)
PASSIVE VENT CAPPED (PHASE 1)
PASSIVE VENT TO CK/TSIDE (PI IASE 2)
ACTIVE VENT TO OUISIDE (PHASE 3)
APPROXItMTE SCALE 1/8 INCH = 1 FOOT
Figure 4.10-1. House ON-17 foundallon door plan
-------
TABLE 4.18-2. HOUSE ON-17
INSTALLED MITIGATION TECHNIQUES
PHASE 0 - BASELINE RADON-RESISTANT CONSTRUCTION:
INSTALL CONTINUOUS AIRTIGHT POLYETHYLENE FILM OVER
AGGREGATE BEFORE SLAB IS POURED TO FOUNDATION WALL.
• ADHERE PLASTIC FILM TO TOP OF FOOTINGS AND FOUNDATION
WALLS WITH BITUMINOUS ROOFING CEMENT.
• TOOL PERIMETER EDGE OF SLAB AND FILL WITH POLYURE-
THANE CAULK.
INSTALL CONTINUOUS LAYER OF PORTLAND CEMENT WITH BITUMI-
NOUS COATING AROUND EXTERIOR FOUNDATION WALL AND FOOTING.
INSTALL COURSE OF TERMITE BLOCKS AT GRADE LEVEL.
iPHASE 1 -
iPHASE 2 -
INSTALL INTERIOR FOOTING DRAINS (WHICH DISCHARGE INTO
AIR-TIGHT SUMP) IN BASEMENT AND CRAWL SPACE. PROVIDE FOR
VENTING FOOTING DRAINS AND SUB-SLAB IN ONE LOCATION.
FOR PHASE 0, VENT SUB-SLABS INTO BASEMENT AND CRAWL SPACE.
SEAL BELOW-GRADE OPENINGS AND CAP VENT.
SEAL BELOW-GRADE OPENINGS AND PASSIVELY VENT BASEMENT
AND CRAWL SPACE SUB-SLABS TO OUTSIDE USING VENT AT RIM
JOIST.
IPHASE 3 - SEAL BELOW-GRADE OPENINGS, CAP ONE VENT, AND ACTIVELY
DEPRESSURIZE BASEMENT AND CRAWL SPACE SUB-SLABS USING
SECOND VENT.
4.18-4
-------
25
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00
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20 -
15 -
10
0 -
PHASED-BASELINE
PHASE 1-SEAL
PI IASE 2 - SEAL, VENT SUB-SLAB
PHASE 3 - SEAL, DEPRESSURIZE SUB-SLAB
PHASE 1 AVG. 8.1 pCl/1
PHASE OAVG. 7.7 pCI/I
PI IASE 2 AVG. 7.0 pCI/1
1 1 1 i r i i i i i 1 1—
2/22/89 2/23/89 2/24/89 2/25/09 2/26/89 2/27/89 2/20/89 3/1/89 3/2/89 3/3/89 3/4/89 3/5/89 3/6/89
DATE (mm/dd/yy)
Figure 4.10-2. Houso ON-17 radon concenlratlons: phaso 0, phase 1, phase 2, and phase 3
-------
TABLE 4.18-3. HOUSE ON-17
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (DCi/L)
MONITORING
PHASE DETECTOR* PERIOD
2 CC
2 CR
0 CR
1 CR
3 CR
3 CC
02/11/89
02/22/89
02/24/89
02/28/89
03/03/89
03/03/89
- 02/14/89 -
- 02/24/89
- 02/28/89
- 03/03/89
- 03/07/89
- 03/07/89
BASEMENT
7.6
6.7
7.7
8.1
2.1
0.9
FIRST SECCND
FLOOR FLOOR
5.6 4.6
- -
- -
- -
- -
0.6 0.8
*CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
4.18-6
-------
4.19 HOUSE ON-18
Description
Table 4.19-1 summarizes the characteristics of house ON-18. Figure 4.19-1 shows the
foundation floor plan. The house is a single-family colonial with a full basement and an attached
garage at ground level. The house was built in 1988. The bedrock, which is near the surface, is
highly fractured Onondaga Limestone. The foundation was excavated directly into the fractured
bedrock and the bedrock debris was used as backfill around the exterior of the foundation walls.
Hollow-core concrete blocks, with termite blocks on the top course, were used to build the
foundation walls. Interior footing drains discharge into a sump. Apparently, the footing drain loop
was cut in half when the sewer line was installed (see Figure 4.19-1). Provisions were made for
venting the footing drains and sub-slab to the outside in one location.
Combustion appliances in the basement include a gas-fired domestic water heater and gas-
fired forced-air furnace.
Installed Mitigation Techniques
Table 4.19-2 summarizes the mitigation techniques tested in this house. Figures 4.19-2,4.19-3,
4.19-4, 4.19-5 and 4.19-6 show continuous radon measurement results during Phases 0 to 3. Table
4.19-3 summarizes the integrated radon concentrations for each of the monitoring periods.
Discussion of Results
Continuous radon measurements during October 1988 indicated average basement levels of
43.8 pCi/L and 57.6 pCi/L (see Figures 4.19-2 and 4.19-3). During February and early March 1989
another set of continuous radon measurements were taken with the following results: Phase 0, 24.9
pCi/L; Phase 1, 26.2 pCi/L; Phase 2, 28.2 pCi/L; and Phase 3, 21.0 pCi/L (see Figure 4.19-4).
There was no significant difference between radon levels during the first three phases (Phase 0, Phase
1, and Phase 2) and unlike the other new houses in this project, radon levels were not dramatically
reduced during Phase 3. When the sub-slab depressurization fan was replaced by a larger fan (Phase
3B), there was a further reduction (from 21.0 pCi/L to 16.1 pCi/L and 16.9 pCi/L) but nowhere near
the 4 pCi/L guideline (see Figure 4.19-5). Reversing the larger fan to provide for sub-slab
pressurization reduced radon concentrations still further, to 8.1 pCi/L, but still above the 4 pCi/L
guideline (see Figures 4.19-5 and 4.19-6).
One of the main reasons for the lack of effectiveness of the sub-slab depressurization system
was poor sub-slab communication across the basement as measured by smoke sticks at pilot holes
when the large depressurization fan was operating. According to the builder, when the main sewer
4.19-1
-------
pipe was installed, the sub-slab footing drain was severed and the sub-slab aggregate was disturbed,
causing a discontinuity of communication across the line of the sewer pipe. One method that is
expected to correct this mitigation system would be to provide a second suction point at the far end
of the basement. This additional step was not investigated during this project.
4.19-2
-------
TABLE 4.19-1. HOUSE ON-18
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1988
PUBLIC
FOUNDATION STRUCTURE: WALK-OUT FULL BASEMENT
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
6 FEET (1.8 METERS)
CONCRETE BLOCK WITH TOP COURSE
OF TERMITE BLOCKS
SPACE BETWEEN TERMITE BLOCKS
BARE CONCRETE
PERIMETER FRENCH DRAIN AND SUMP
CRUSHED STONE
INTERIOR COMPLETE LOOP TO
VENTED SUMP
UPSTAIRS
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS, JENAIR
4.19-3
-------
I
® •
V VENT SUMP
(FAN INSTALLED) yVElL
(COVEHED)
HOLLOW CONCRETE BLOCK WALLS WITH TERMfTE BLOCKS ON TOP COURSE
D
OARAQE (OHAOG LEVEL)
MAIN SEWER: j
PICE J •
OWN
APPROXIMATE SCALE 1/8 INCH = 1 FOOT
Figure 4.19-1. House ON-18 foundation floor plan
-------
TABLE 4.19-2. HOUSE ON-18
INSTALLED MITIGATION TECHNIQUES
PHASE 0 BASELINE RADON-RESISTANT CONSTRUCTION:
PROVIDE FOR PERIMETER FRENCH DRAIN AROUND BASEMENT SLAB.
INSTALL CONTINUOUS LAYER OF SURFACE-BONDING CEMENT
AROUND EXTERIOR FOUNDATION WALLS AND FOOTING.
INSTALL INTERIOR FOOTING DRAINS (WHICH DISCHARGE INTO
SUMP) IN BASEMENT. PROVIDE FOR VENTING FOOTING DRAINS
AND SUB-SLAB IN ONE LOCATION. FOR PHASE 0, VENT SUB-SLAB
INTO BASEMENT.
PHASE 1 SEAL BELOW-GRADE OPENINGS AND CAP VENT.
PHASE 2 SEAL BELOW-GRADE OPENINGS AND PASSIVELY VENT BASEMENT
SUB-SLAB TO OUTSIDE USING ONE VENT THROUGH ROOF.
PHASE 3A- SEAL BELOW-GRADE OPENINGS AND ACTIVELY DEPRESSURIZE
BASEMENT SUB-SLAB USING 48-WATT FAN.
PHASE 3B- SAME AS PHASE 3A EXCEPT USE 90-WATT FAN.
PHASE 3C- SAME AS PHASE 3B EXCEPT 90-WATT FAN INVERTED.
4.19-5
-------
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GO
20 -
0 -
PHASED-BASELINE
PIIASEOAVG. 57.6 pCi/1
EPA GUIDELINE (-1 pCi/1)
10/11/00
Figure 4.19-3. Houso ON-IO radon concenlralions: phaso 0
10/12/00
DATE (mm/dd/yy)
10/13/08
-------
00 -
to
CD
g 60 -
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HI
01
CO
40 -
20 -
0
PHASE 0 - BASELINE
PHASE 1 - SEAL
PHASE 2 - SEAL, VENT SUB-SLAB
PHASE 3A - SEAL, DEPRESSURIZE SUB-SLAB
PHASE 2 AVG. 20.2 pCi/1 PHASE 1 AVG. 20.2 pCVl
PHASE 0 AVG. 2-1.9 pCi/1
w^V\
\
PHASE 3A AVG. 21.0 pCl/l
.EP.A.GUjfDELINE (1 pCI/1)
I
I
I
I
T
T
2/22/09 2/23/09 2/24/09 2/25/09 2/26/09 2/27/09 2/20/09 3/1/09 3/2/09 3/3/69 3/4/69 3/6/09
DATE (mm/dd/yy)
Figure 4. 19-4. Mouse ON-18 radon concentrations: phase 0, phase I, phase 2, and phase 3A
-------
00
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60 -
20 -
0
PI IASE 3A - SEAL, DEPRESSURIZE SUB-SLAB (18 WATT FAN)
PI IASE 3D - SEAL, DEPRESSURIZE SUB-SLAB (90 WATT FAN)
PI IASE 3C - SEAL, PRESSURIZE SUB-SLAB (90 WATT FAN)
PI IASE 3AAVG. 21.0 pCi/1
PIIASE3DAVG. 16.9pCi/l
EPAGUIDELINE(1pCI/l)
T
1 I
3/6/09 3/7/89 3/8/89 3/9/89 3/10/89
DATE (mm/dd/yy)
Figure 4.19-5. Mouse ON-18 radon concentrations: phase 3A, phase 3B,and phase 3C
3/11/89
I
3/12/89
-------
TABLE 4.19-3. HOUSE ON-18
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (vCUL)
PHASE
0
0
2
0
1
3A
3A
3A
3B
3B
3C
3C
3C
MONITORING
DETECTOR* PERIOD
CR
CR
CR
CR
CR
CC
CR
CR
CR
CR
CR
CR
CC
10/07/88
10/11/88
02/23/89
02/24/89
02/27/89
03/01/89
03/02/89
03/06/89
03/08/89
03/09/89
03/10/89
03/20/89
03/20/89
- 10/09/88
- 10/13/88
- 02/24/89
- 02/27/89
- 03/01/89
- 03/06/89
- 03/06/89
- 03/08/89
- 03/09/89
- 03/10/89
- 03/13/90
03/23/890
- 03/23/89
BASEMENT
43.8
57.6
28.2
24.9
26.2
24.0
21.0
21.0
16.1
16.9
8.1
8.1
8.4
FIRST SECOND
FLOOR FLOOR
- -
- -
- -
- -
20.1 20.0
- -
- -
- -
- -
- -
- -
6.9 7.1
*CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
4.19-10
-------
4.20 HOUSE ON-19
Description
Table 4.20-1 summarizes the characteristics of house ON-19. Figure 4.20-1 shows the
foundation floor plan. The house is a single-family colonial with a basement, a crawl space, and an
attached garage at ground level. The house was built in 1989 in the same area as test houses ON-06,
ON-07, ON-08, ON-20 and control house ON-03. The bedrock, which is near the surface, is highly
fractured Marcellus Shale. The foundation was excavated directly into the fractured bedrock and the
bedrock debris was used as backfill around the exterior of the foundation walls. Hollow-core concrete
blocks, with termite blocks at grade level, were used to build the foundation walls. A complete loop
of interior footing drains discharge into a sump. Provisions were made in two locations for venting
the footing drains and sub-slab to the outside.
Combustion appliances in the basement include a gas-fired domestic water heater and gas-
fired forced-air furnace.
Installed Mitigation Techniques
Table 4.20-2 summarizes the mitigation techniques tested in this house. Figures 4.20-2 and
4.20-3 show continuous radon measurement results during Phases 0 to 3. Table 4.20-3 summarizes
the integrated radon concentrations for each of the monitoring periods indicated.
Discussion of Results
With the sub-slab vents open to the basement (Phase 0) in early February 1989, continuous
radon measurements were 16.4 pCi/L in the basement (see .Figure 4.20-3). Later in February and
early March 1989, continuous radon measurements indicated 10.3 pCi/L during Phase 2, 11.7 pCi/L
during Phase 0, 11.5 pCi/L during Phase 1, and 3.3 pCi/L during Phase 3 (see Figure 4.20-3). For
the first part of Phase 2 there is a large dip in the radon concentrations on the afternoon of February
17, 1989 (sec Figure 4.20-3). It is this dip that accounts for the lower radon- levels of Phase 2
compared to Phases 0 and 1. The most likely explanation for the dip on February 17 is that workers
opened the windows of the house to provide ventilation. Radon levels were not significantly different
for the first three phases (Phase 0, Phase 1, and Phase 2). Only during Phase 3, when the sub-slab
was actively dcpressurizcd, was there a significant decrease in radon levels. Basement radon levels
during Phase 3 were 3.3 pCi/L, according to a continuous monitor, and 3.6 pCi/L, according to
4.20-1
-------
a charcoal canister. Phase 3 charcoal canister results on the first and second floors were 3.1 pCi/L
and 3.2 pCi/L, respectively (see Table 4.20-3).
4.20-2
-------
LAXLZ 4.ZU-1. HOUSE
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1989
PUBLIC
FOUNDATION STRUCTURE: 80% BASEMENT, 20% CRAWL SPACE
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
6 FEET (1.8 METERS)
CONCRETE BLOCK WITH TERMITE
BLOCKS AT GRADE LEVEL
NONE
BARE CONCRETE OVER PLASTIC FILM
NONE
CRUSHED STONE
INTERIOR COMPLETE LOOP TO
SUMP
NONE
AVERAGE HEIGHT OF CRAWL SPACE:
CRAWL SPACE WALLS:
CRAWL SPACE FLOOR SURFACE:
CRAWL SPACE VENTILATION:
CRAWL SPACE INSULTATION:
ACCESS TO CRAWL SPACE:
4 FEET (1.2 METERS)
CONCRETE BLOCK WITH TERMITE
BLOCKS AT GRADE LEVEL
BARE CONCRETE OVER PLASTIC FILM
AND CRUSHED STONE
NONE
EXTERIOR WALLS
UPSTAIRS
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.20-3
-------
CIWWL SPACE
QAAAQE (onAOE LEVEL)
HOLLOW CONCRETE BLOCK WALLS WFTH TERMITE BLOCKS AT GRADE LEVEL
PASSIVE VENT TO INSIDE (PHASE 0)
* PASSIVE VENT CAPPED {PI IASE 1)
SUB siAB CONNECT™ PIPE TO CIUWL SPACE PASSJVE w" T0 <*™K I™*8* *>
ACTIVE VENT TO OUTSIDE (PHASE 3)
FUHNACE
PASSWE VENT TO INSIDE (PVIASE 0)
PASSJVE VENT CAPPED (PHASES 1 A3)
PASSIVE VENT TO OUTSIDE (PHASE 2)
APPROXIMATE SCALE 1/8 INCH = 1 FOOT
Figure 4.20-1. House ON-19 foundation floor plan
-------
TABLE 4.20-2. HOUSE ON-19
INSTALLED MITIGATION TECHNIQUES
PHASE 0 BASELINE RADON-RESISTANT CONSTRUCTION:
INSTALL CONTINUOUS AIRTIGHT POLYETHYLENE FILM OVER
AGGREGATE BEFORE SLAB IS POURED TO FOUNDATION WALL.
• ADHERE PLASTIC FILM TO TOP OF FOOTINGS AND FOUNDATION
WALLS WITH BITUMINOUS ROOFING CEMENT.
• TOOL PERIMETER EDGE OF SLAB AND FILL WITH POLYURE-
THANE CAULK.
INSTALL CONTINUOUS LAYER OF PORTLAND CEMENT WITH BITUMI-
NOUS COATING AROUND EXTERIOR FOUNDATION WALL AND FOOTING.
INSTALL COURSE OF TERMITE BLOCKS AT GRADE LEVEL.
INSTALL INTERIOR FOOTING DRAINS (WHICH DISCHARGE INTO
AIR-TIGHT SUMP) IN BASEMENT AND CRAWL SPACE. PROVIDE FOR
VENTING FOOTING DRAINS AND SUB-SLABS IN TWO LOCATIONS.
FOR PHASE 0, VENT SUB-SLABS INTO BASEMENT AND CRAWL SPACE.
PHASE 1 SEAL BELOW-GRADE OPENINGS AND CAP TWO VENTS.
PHASE 2 SEAL BELOW-GRADE OPENINGS AND PASSIVELY VENT BASEMENT
SUB-SLAB TO OUTSIDE USING TWO VENTS AT RIM JOIST.
PHASE 3 SEAL BELOW-GRADE OPENINGS, CAP ONE VENT, AND ACTIVELY
DEPRESSURIZE BASEMENT AND CRAWL SPACE SUB-SLABS USING
SECOND VENT.
4.20-5
-------
25 -
o
Z
o
Q.
O
I
111
o
^.
o
o
-z.
o
Q
LLJ
m
20 -
15
10 -
5 -
0
PHASE 0 - BASELINE
PHASE OAVG. 16.4 pCi/l
A T /\
EPA GUIDELINE (
-------
25 -i
N)
O
I
O
a.
Z
O
UJ
O
Z
O
O
Z
O
Q
2
UJ
s
UJ
m
20
15 -
10 -
0 -
PI IASE 0 - BASELINE
PI lASE 1 - SEAL
PI IASE 2 - SEAL, VENT SUB-SLAB
PI IASE 3 - SEAL, DEPRESSURIZE SUB-SLAB
PHASE2AVG. 10.3pCl/l
PI IASE 0 AVG. 11.7 pCl/1
PHASE 1AVG. II.SpCi/1
PHASE 3 AVG. 3.3 pO/1
r-
2/17/09 2/19/09 2/21/89 2/23/89 2/25/89 2/27/89 3/1/89
2/18/89 2/20/89 2/22/89 2/24/89 2/26/89 2/28/89 3/2/89
DATE (mm/dd/yy)
Flguro 4.2O-3. House ON-19 radon concentrations: phase 0, phase 1, phase 2, and phase 3
-------
TABLE 4.20-3. HOUSE ON-19
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (pCi/L)
MONITORING
PHASE DETECTOR* PERIOD
0 CR
2 CR
0 CR
1 CR
3 CR
3 CC
02/01/89
02/17/89
02/21/89
02/24/89
02/27/89
02/28/89
- 02/03/89
- 02/21/89
- 02/24/89
- 02/27/89
- 03/03/89
- 03/03/89
BASEMENT
16
10
11
11
3
3
.4
.3
.7
.5
.3
.6
FIRST SECOND
FLOOR FLOOR
.
- -
- -
-
- -
3.1 3.2
*CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
4.20-8
-------
4.21 HOUSE ON-20
Description
Table 4.21-1 summarizes the characteristics of house ON-20. Figure 4.21-1 shows the
foundation floor plan. The house is a single-family colonial with a basement and an attached garage
at ground level. The house was built in 1989 in the same area as test houses ON-06, ON-07, ON-08,
ON-19 and control house ON-03. The bedrock, which is near the surface, is highly fractured
Marcellus Shale. The foundation was excavated directly into the fractured bedrock and the bedrock
debris was used as backfill around the exterior of the foundation walls. Hollow-core concrete blocks,
with termite blocks at grade level, were used to build the foundation walls. A complete loop of
interior footing drains discharge into a sump. Provisions were made for venting the footing drains
and sub-slab to the outside in two locations.
Combustion appliances in the basement include a gas-fired domestic water heater and gas-
fired forced-air furnace.
Installed Mitigation Techniques
Table 4.21-2 summarizes the mitigation techniques tested in this house. Figures 4.21-2 shows
continuous radon measurement results during Phases 0 to 3. Table 4.21-3 summarizes the integrated
radon concentrations for each of the monitoring periods.
Discussion of Results
Charcoal canister measurements were made in house ON-20 during January 1989, while the
sub-slab was passively vented (Phase 2). The results of these measurements were 20.5 pCi/L in the
basement, 15.2 pCi/L on. the first floor, and 15.5 pCi/L on the second floor (see Table 4.21-3).
Continuous radon measurements in the basement during February and early March 1989, indicated
24.7 pCi/L during Phase 0, 20.3 pCi/L during Phase 1, 23.2 pCi/L during Phase 2, and 2.8 pCi/L
during Phase 3. There is no significant difference in radon levels between the first three phases
(Phase 0, Phase 1, and Phase 2), whereas radon levels were definitely reduced during Phase 3 to
below the 4 pCi/L guideline. Basement radon levels during Phase 3 were 2.8 pCi/L according to a
continuous monitor and 2.0 pCi/L according to a charcoal canister. Phase 3 charcoal canister results
on the first and second floors were 1.5 pCi/L and 2.0 pCi/L, respectively (see Table 4.21-3).
4.21-1
-------
TABLE 4.21-1. HOUSE ON-20
BUILDING CHARACTERISTICS
STYLE:
YEAR BUILT:
WATER SUPPLY:
COLONIAL
1989
PUBLIC
FOUNDATION STRUCTURE: FULL BASEMENT
AVERAGE DEPTH OF
BASEMENT FLOOR BELOW-GRADE:
BASEMENT WALLS:
BASEMENT WALL OPENINGS:
BASEMENT FLOOR SURFACE:
BASEMENT FLOOR OPENINGS:
SUB-FLOOR AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
6 FEET (1.8 METERS)
CONCRETE BLOCK WITH TERMITE
BLOCKS AT GRADE LEVEL
NONE
BARE CONCRETE OVER PLASTIC FILM
NONE
CRUSHED STONE
INTERIOR COMPLETE LOOP TO
SUMP
UPSTAIRS
CONSTRUCTION ABOVE FOUNDATION:
EXTERIOR CLADDING:
CENTRAL HEATING SYSTEM:
FIRE PLACES/WOOD STOVES:
VENTS AND OPENINGS:
FRAME
WOOD
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.21-2
-------
HOLLOW CONCRETE BLOCK WALLS WITH TEFlMfTE BLOCKS AT GRADE LEVEL
K)
i—i
OJ
PASSIVE VENT TO INSIDE (PHASE 0)
PASSIVE VENT CAPPED (PI IASE I)
PASSIVE VENT TO OUISIDE (PI IASE 2)
ACTIVE VENT TO OUISIDE (I'llASE 3)
PASSWE VENT TO INSIDE {PHASE 0)
PASSIVE VENT CAPPED (PI IASES 1 & 3)
PASSIVE VENT TO OUTSIDC (PHASE i)
OARAOE (ORADe LEVEL)
APPROXIMATE SCALE 1/0 INCH = 1 FOOT
Figure 4.21-1. House ON-20 foundation floor plan
-------
TABLE 4.21-2. HOUSE ON-20
INSTALLED MITIGATION TECHNIQUES
PHASE 0 - BASELINE RADON-RESISTANT CONSTRUCTION:
INSTALL CONTINUOUS AIRTIGHT POLYETHYLENE FILM OVER
AGGREGATE BEFORE SLAB IS POURED TO FOUNDATION WALL.
• ADHERE PLASTIC FILM TO TOP OF FOOTINGS AND FOUNDATION
WALLS WITH BITUMINOUS ROOFING CEMENT.
• TOOL PERIMETER EDGE OF SLAB AND FILL WITH URETHANE
CAULK.
INSTALL CONTINUOUS LAYER OF PORTLAND CEMENT WITH BITUMI-
NOUS COATING AROUND EXTERIOR FOUNDATION WALL AND FOOTING.
INSTALL COURSE OF TERMITE BLOCKS AT GRADE LEVEL.
INSTALL INTERIOR FOOTING DRAINS (WHICH DISCHARGE INTO
AIR-TIGHT SUMP) IN BASEMENT. PROVIDE FOR VENTING FOOTING
DRAINS AND SUB-SLABS IN TWO LOCATIONS. FOR PHASE 0, VENT
SUB-SLAB INTO BASEMENT.
PHASE 1 SEAL BELOW-GRADE OPENINGS AND CAP TWO VENTS.
PHASE 2 - SEAL BELOW-GRADE OPENINGS AND PASSIVELY VENT BASEMENT
SUB-SLAB TO OUTSIDE USING TWO VENTS AT RIM JOIST.
PHASE 3 SEAL BELOW-GRADE OPENINGS, CAP ONE VENT, AND ACTIVELY
DEPRESSURIZE BASEMENT SUB-SLAB USING SECOND VENT.
4.21-4
-------
0 CO
CL
Z
O
M--
UJ
O
O 40
O
Z
O
D
h-
UJ
S
UJ
m
20 -
0 -
PI IASE 0 - BASELINE
PHASE 1 -SEAL
PI IASE 2 - SEAL, VENT SUB-SLAB
PI IASE 3 - SEAL, DEPRESSURIZE SUB-SLAB
PHASE 2 AVG. 23.2 pCI/l
PI IASE OAVG. 21.7 pCI/1
PHASE 1 AVG. 20.3
PHASE 3 AVG. 2.8 pCi/I
1 n i i i i i i i i i i i 1 r~
2/17/09 2/19/89 2/21/09 2/23/89 2/25/89 2/27/89 3/1/89 3/3/89
2/10/89 2/20/89 2/22/89 2/24/89 2/26/89 2/28/89 3/2/89 3/4/89
DATE (mm/dd/yy)
Figure 4.21-2. House ON-20 radon concentrations: phase 0, phase 1, phase 2, and phase 3
-------
TABLE 4.21-3. HOUSE ON-20
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (pCi/L)
MONITORING
PHASE DETECTOR* PERIOD
2 CC
2 CR
0 CR
1 CR
3 CR
3 CC
01/16/89
02/17/89
02/23/89
02/25/89
02/27/89
03/01/89
- 01/19/89
- 02/23/89
- 02/25/89
- 02/27/89
- 03/04/89
- 03/04/89
BASEMENT
20.
23.
24.
20.
2.
2.
5
2
7
3
8
0
FIRST SECOND
FLOOR FLOOR
15.2 15.5
- -
- -
- -
- -
1.5 2.0
*CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
4.21-6
-------
4.22 NEW HOUSE DEMONSTRATION: SUMMARY OF RESULTS AND CONCLUSIONS
Four types of radon-resistant construction techniques were studied in new houses:
• Sealing Foundation Floors
• Sealing Concrete Block Foundation Walls
• Passive Sub-Slab Ventilation
• Active Sub-Slab Depressurization.
Sealing Foundation Floors
The foundation floor was sealed in all test houses except ON-18 by installing a continuous
airtight plastic film over the sub-slab aggregate before the slab was poured and adhering the plastic
to the inside footing. The slab was then poured to the foundation wall and the perimeter tooled to
accept a bead of polyurethane caulk. Joints, tears, punctures, slits, or penetrations of the plastic film
were sealed airtight with builder's tape. The interior and/or exterior footing drains were discharged
to daylight whenever possible to avoid the introduction of an interior sump. If the footing drains
discharged into an interior sump, the sump was made airtight. To reduce shrinkage and cracks in the
slab, the water content of the concrete mix was recommended to be as lean as possible.
Houses ON-06, ON-09, and ON-10 were extensively inspected before, during, and after the
slab was poured. Careful inspections were made of the process of using builder's tape to seal the film
airtight and the process of adhering the plastic film to the top of the footing. Less extensive spot
checks were made of the remaining test houses before and after the slab was poured. Some
observations during these inspections are recounted below.
When the footing was below the level of the sub-slab aggregate, the plastic film had to be
adhered to the base of the foundation walls (instead of to the top of the footing). For the first few
test houses in the demonstration, the plastic film was adhered to the top of the footing by a generous
layer of roofing cement troweled onto the footing. In later test houses, instead of troweling the
roofing cement on the footing, a heavy bead of roofing cement from a large caulking gun was used
along the footing (or, in the case when the footing was below the level of the aggregate, along the
base of the foundation walls).
Originally there was also to be a strip of roofing cement on the perimeter of the top of the
plastic film, but the masons reacted so negatively during a demonstration that this procedure was
abandoned. The masons objected because it seemed impossible to keep the roofing cement off tools
and footwear when pouring the concrete, and once on tools and footwear it was difficult to remove.
Despite the recommendation to use a lean water mix in the cement for the slab, the slab
concrete contained far too much water in all cases. It is unclear what effect the plastic film under
4.22-1
-------
the slab had on cracking. Some foundation contractors argue that the plastic slows the curing process
and reduces cracking while others argue that the plastic film increases the moisture problem by not
allowing the moisture to migrate below, thus increasing cracking. For this study there appeared to
be no difference in the number of cracks in slabs of the test houses and the control houses.
Approximately 50 percent of the slabs had cracks for both the test and control houses.
One concern with pouring the slab to the foundation wall was providing a break between the
slab and the foundation wall, so that the slab would not adhere to the foundation wall and thus
produce cracks elsewhere. According to the original design, the slab/wall break was to be provided
by the sub-slab plastic film that was to run from under the slab, up the side of the foundation wall,
and later be trimmed to just below the surface of the slab. In some cases, however, the plastic did
not reach up the side of the foundation wall. In the few places where this was noticed, there
appeared to be no indication that this procedure increased cracking problems in other areas in the
floor slab.
No continuous radon data was collected for houses ON-06 and ON-08 which had relatively
low radon levels. These houses were built early in the project when there were frequent inspections
and QA/QC for checking the construction was favorable. In addition, these houses did not have an
interior sump since the interior and exterior footing drains discharged to daylight. It might be
expected that these houses were good candidates to have low radon levels. However, these houses
also had favorable soil conditions (basements were not built into fractured bedrock, and fractured
bedrock was not used as backfill). It is difficult to determine if low radon levels were due to soil
conditions or to effective foundation sealing.
Direct evidence of the effectiveness of sealing the foundation floor may be obtained from an
examination of continuous radon monitoring results. These results of Task II are summarized in
Tables 4.22-1 and 4.22-2.
4.22-2
-------
TABLE 4.22-1
RESULTS FROM NEW CONSTRUCTION TEST SITES
AS-BUILT
HOUSE
ID
ON-061'2
ON-072
ON-081'2
ON-09
ON-10
ON-11
ON-12
ON-13
ON-144
ON-15
ON-16
ON-I7
ON-186
ON- 19
ON-20
CONCENTR
(pCi/L)
3 5
4-7
5
29
6-8
8
4
13 18
N/A
7
25
8
25 58
12 16
25
PASSIVE
VENTILATION
CONCENTRATION
(pCi/L)
3 5
N/A
5
19 20
6 8
7 8
4
10
N/A
6-7
14
7
28
10
21 23
ACTIVE
DEPRESSURIZATION
CONCENTRATION
(pCi/L)
N/A
N/A
N/A
1
<1
2
2
2
2
1 2
2
1 2
8
3 -4
2 3
Notes:
1. Vented drains discharged to daylight.
2. Homeowner decided not to install active depressurization system.
3. N/A = not available, phase was not investigated.
4. Results from as-built and with passive ventilation are not available.
5. All results are from various measurement devices including AT, CC, and CR.
6. Sub-slab radon-resistant techniques installed incorrectly including a severed sub-slab
drain.
4.22-3
-------
TABLE 4.22-2
RESULTS FROM NEW CONSTRUCTION CONTROL SITES
ACTIVE
AS-BUILT DEPRESSURIZATION
HOUSE CONCENTRATION CONCENTRATION
ID (pCi/L) (pCi/L)
ON-01 33 3
ON-02 7 3
ON-03 27 2
ON-04 25 3
ON-05 19 3
Notes: All results are from various measurement devices including AT, CC and CR.
In house ON-07, there appeared to be an increase in radon levels after the sump was sealed
(see Figure 4.8-2). This change may be explained by slab cracks near the radon monitor which may
have produced an increased radon flow once the sump was sealed (despite the sub-slab plastic film).
Additional monitoring is needed in this house to understand these results more fully and eliminate
assumptions.
Although continuous radon levels in house ON-20 indicate slightly lower radon levels for
Phase 1 compared to Phase 0, the difference could also be explained by natural variations of radon
due to causes other than sealing the foundation floor.
There appear to be distinct decreases in radon levels between Phases 0 and 1 only in houses
ON-09 and ON-13 (see Figures 4.10-4 and 4.14-3). However, these changes were not enough to
reduce radon levels below the 4 pCi/L guideline.
The evidence to support the effectiveness of these special floor sealing techniques as the sole
mitigation method was not strong because of the various other factors that interact with sealing the
floor. These factors include passive ventilation, the integrity of the wall structure in preventing radon
passage, and the initial radon level in the soil surrounding the house.
4.22-4
-------
Sealing Concrete Block Foundation Walls
All the control houses and the new test houses had concrete block foundation walls. An
obvious problem with concrete block walls occurs when it is necessary to build sub-foundations below
the normal level of the footing. This occurred for control house ON-05 and test houses ON-10, ON-
11, ON-12, ON-13, ON-15, and ON-16 in order to build on undisturbed soil or to provide for a walk-
out basement. The sub-foundation normally consists of a footing poured on solid undisturbed soil
on which the concrete block foundation wall is built up to the level of the normal footing or the level
of the sub-slab aggregate. Since the primary concern in coating the outside walls is to prevent water
migration through the walls into the basement, sub-foundation walls usually are not coated below the
slab level. However, this allows radon to migrate through the uncoated concrete blocks below the
slab into the block cavity and up through the blocks into the basement.
In order to avoid this problem with sub-foundations, the builder was instructed to install, level
with the aggregate, a course of termite blocks with the cap down. This was implemented in houses
ON-11 and ON-15. Then in houses ON-12, ON-13 and ON-15, the termite blocks were filled with
concrete to provide an additional radon barrier and provide additional strength.
The control houses had open concrete blocks except on the top course. Test houses ON-06,
ON-07, and ON-18 had termite blocks on the top course while test house ON-08 had concrete blocks
filled with mortar on the top course. The remaining test houses (houses ON-09, ON-10, ON-11,
ON-12, ON-13, ON-14, ON-15, ON-16, ON-17, ON-19, and ON-20) all had a course of termite
blocks at grade level (not on the top course). Above this level the remaining concrete blocks were
narrower to allow for insulation to be inserted on the inside foundation wall, from grade level to the
top of the wall. Insulation on the exterior of the foundation wall extended from grade level to
approximately three feet below grade. Unfortunately, this was not an effective method of insulating
the foundation walls since there is a thermal conduction bridge between the inside and outside at
grade level. In addition, the block cavities allow convection air to circulate from the warm, interior,
uninsulated lower portion of the basement wall to the cold, exterior, uninsulated, upper portion of
the wall. Installing the course of termite blocks at grade level also hid most of the top of the blocks
from view, so it was difficult to see if termite blocks were always used, and if used, how well the
mortar joint between them was filled. In fact, sometimes there were missing termite blocks or missing
pieces of termite blocks. The mortar joints between termite blocks were sometimes not filled.
The exterior of the foundation walls from the top of the foundation wall to the footing level
(if there were no sub-foundation) or to just below the slab level (if there were a sub-foundation)
were pargeted. Houses ON-01, ON-02, ON-04, ON-09, ON-10, ON-11, ON-12, ON-13, ON-14, ON-
15, ON-16, ON-17, ON-19, and ON-20 were pargeted with Portland cement with a bituminous
4.22-5
-------
coating. The remaining houses, ON-03, ON-05, ON-06, ON-07, ON-08, and ON-12, were pargeted
with surface bonding cement. One of the houses (house ON-07) was pargeted on both sides of the
foundation wall with surface bonding cement.
No attempt was made to directly monitor the radon-resistance of the concrete block
foundation walls of these houses as it was above the scope of this project and would involve detailed
laboratory tests. Radon concentration levels measured after the house was constructed reflected the
effectiveness of the entire system. These measurements could not be used to identify which part of
the radon-resistant system was the pathway for radon infiltration or even to determine if each part
was equally responsible for the elevated radon level. However, there is a need for data of this nature
as the concrete block foundation walls are believed to be the major contributor of radon infiltration
to the basement. Additional studies in this area are, therefore, recommended.
One possible method of making concrete block foundation walls more effective against radon
(and water) entry may be to dry stack the concrete blocks (with no mortar between joints) and apply
surface bonding cement on both sides of the foundation wall and over the top of the termite blocks
on the top course. Theoretically, this method should give a stronger and more radon and water
resistant foundation wall. However, this method was not pursued during this project because building
contractors did not want to use this construction method on their houses.
Passive Sub-Slab Ventilation
All of the new test houses and the control houses had interior and/or exterior footing drains
surrounded by at least a four-inch layer of crushed stone. Passive sub-slab ventilation would be
expected to be most effective if the sub-slab aggregate and sub-slab drain pipes were vented from a
central location with a large diameter straight vent pipe directly to the peak of the roof. (This may
be called sub-slab "stack" ventilation). However, to keep costs to a minimum and make installation
as simple as possible,'all (except one) of the passive sub-slab ventilation systems consisted of four-inch
PVC pipes connected to the footing drains in one to three locations. The PVG pipes were routed
to the outside at the rim joist (except for house ON-18 which exhausted through the roof). It was
thought that having more than one passive vent may provide sub-slab "cross" ventilation whenever
pressure differences developed between the two or more vent openings.
The evidence to support the effectiveness of passive sub-slab ventilation, while positive, was
not strong. No continuous radon data were collected for houses ON-10 and ON-14 which had
relatively low radon levels. It might be expected that these houses provided evidence for the
effectiveness of passive sub-slab ventilation. However, these houses also had favorable soil conditions
(basements were not built into fractured bedrock, and fractured bedrock was not used as backfill) and
4.22-6
-------
it is difficult to determine if low radon levels were due to favorable soil conditions or effective passive
sub-slab ventilation.
Direct evidence of the effectiveness of passive sub-slab "cross" ventilation can be obtained
from an examination of continuous radon monitoring results. In houses ON-12 and ON-18 there
appeared to be slight increases in radon levels between Phase 0 (passive sub-slab ventilation into the
basement) and Phase 2 (passive sub-slab ventilation to the outside). However, closer examination
of Figures 4.13-4 and 4.19-4 indicates that these differences are small compared to the natural
variations of radon, and are quite likely not significant. Likewise, the decreases in radon levels from
Phase 0 to Phase 2 for houses ON-11, ON-15, ON-17, ON-19 and ON-20 were probably not
significant in comparison to the natural changes in radon. (See Figures 4.12-2, 4.16-4, 4.18-2, 4.20-3,
and 4.21-2.)
On the other hand, the decreases in radon levels in houses ON-09 and ON-13 due to passive
sub-slab ventilation, although not enough to reduce radon levels below the 4 pCi/L guideline, appear
to be greater than what might be expected from natural variations in radon. See Figures 4.10-3 and
4.14-3.
Active Sub-Slab Depressurization
The primary emphases in the new construction portion of the project (Task II) were the
development of effective radon barrier techniques and the testing of passive methods of providing
"cross" ventilation of the sub-slab using more than one sub-slab vent exiting through the rim joist.
However, when the results showed that the barrier methods and passive ventilation were not effective
in lowering the radon level below the EPA guideline in most of the test houses, active sub-slab
depressurization systems were installed. In houses where there were two or more sub-slab vents, all
but one of the vents had to be capped and a centrifugal fan installed in line with the remaining vent
pipe. Since the vents exited at the rim joist and the new homeowners strongly objected to the fan
showing on the exterior of the house, the fan was placed in a vertical position, inside, as close to the
rim joist as possible. The obvious disadvantages of placing the fan inside are the possibility of leaks
in the fan itself and in the vent pipe on the positive pressure side of the fan. Venting at the rim joist
also created the possibility of radon re-entry into the basement. In any case, it was still relatively easy
to convert from passive sub-slab ventilation to active sub-slab depressurization and, except for one
house (which had poor sub-slab communication), active sub-slab depressurization produced
unequivocal reductions in radon concentrations below the 4 pCi/L guideline. See Figures 4.10-3,
4.12-2, 4.13-4, 4.14-3, 4.16-4, 4.17-3, 4.18-2, 4.20-3, and 4.21-2.
For the five control houses in the new construction techniques study, active sub-slab
4.22-7
-------
depressurization with sealing was installed with the exit pipe venting through the roof and the
depressurization fan placed in the attic (usually the garage attic). The cost of retrofitting these
systems was approximately three times more than building radon mitigation systems into the house.
All of these installations were effective in reducing radon in the basements of control houses below
4 pCi/L. See Figures 4.2-3, 4.3-2, 4.4-3, 4.5-3, and 4.6-2.
SUMMARY
Radon-resistant new construction techniques demonstrated during this task proved to be
successful at lowering the overall radon level in the houses studied. The radon barrier in the sealed
sub-slab, the sealed concrete block foundation walls, and the sub-slab "cross" ventilation techniques
were of limited effectiveness. However, these building techniques made it simple to effectively
retrofit an passive sub-slab depressurization system into the active ventilation system, and thus reduce
the radon concentration below the EPA guideline. In addition, the cost of incorporating these
techniques when a house is built was shown to be three times lower than the cost of retrofitting
mitigation techniques.
In areas where there is a risk of high radon levels, a new house should be constructed as
specified in this report with sealing and a passive ventilation system consisting of only one passive
vent connected through the attic. This single vent installation is suggested because the passive
ventilation system usually did not lower the radon concentration below the EPA guideline. Whenever
the radon level is above 4 pCi/L, a centrifugal fan should be installed into the sub-slab ventilation
system to provide active depressurization. Results showed that when a site was fitted with a correctly-
installed active depressurization system, this radon-resistant technique was effective at reducing radon
levels below the current EPA guideline.
4.22-8
-------
APPENDIX A
This appendix contains the specific details on the radon reduction techniques demonstrated
in 16 existing homes as described in Section 2 of this report. The figures and tables contained herein
include the building characteristics, floor plans of the buildings, diagnostic measurements maps
illustrating where the radon measurements were taken and their levels, the mitigation techniques
installed by phase at each site, graphs of continuous radon measurements for each mitigation phase,
and tables summarizing all radon measurments taken at each site. These details provide
documentation on the results observed and conclusions reached for each site as presented in Section
2.
A-l
-------
TABLE A-L HOUSE AR-01
BUILDING CHARACTERISTICS
STYLE: BI-LEVEL RAISED RANCH
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
WALL-WALL COMMUNICATION:
FLOOR OPENINGS:
WALL-SUB-SLAB COMMUNICATION:
SUB-SLAB AGGREGATE:
SUB-SLAB COMMUNICATION:
FOOTING DRAINS:
CAPPED BLOCK
MINOR CRACKS
GOOD
SANITARY PIT, MINOR CRACKS
MARGINAL
GRAVELLY SOIL
MARGINAL
NONE
DIAGNOSTIC RADON MEASUREMENTS *
WATER:
CC SCREENING:
GR SCREENING:
GR FOUNDATION WALLS (AVG):
GR SUB-SLAB:
GR SANITARY PIT:
PUBLIC
20 PCI/L
20 PCI/L
300 PCI/L
40 PCI/L
200 PCI/L
*CC = CHARCOAL CANISTER, GR = GRAB SAMPLE RADON
A-2
-------
>
CO
FAMILY ROOM
BATH
WATER HEATER/FURNACE
SEWING ROOM
SANITARY PIT UNDER STAIRS
\
o
5
in
\
STAIRS
GARAGE
Figure A-1. House AR-01 lower level floor plan
-------
LEGEND
S31 - IN SANITARY CLEAN-OUT PIT
SS2 - BENEATH FLOOR SUB IN FURNACE ROOM
W1 - INTERIOR OF BACK WALL
W2 - INTERIOR OF WEST WALL
W2-128pQi/l
SS2 - 42 pCi/l
X
SS1 -197pCi/l
\
\
W1 - 468 pCi/l
Figure A-2. House AR-01 diagnostic measurements map
-------
TABLE A-2. HOUSE AR-01
INSTALLED MITIGATION TECHNIQUES
PHASE 1 - SEAL OBVIOUS BELOW-GRADE OPENINGS AND CRACKS,
INCLUDING SANITARY PIT.
PHASE 2 - PHASE 1 PLUS DEPRESSURIZE BACK AND SIDE WALLS.
A-5
-------
Q.
z
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CC
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o
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o
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z
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DC
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LU
>
UJ
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DC
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O
40
35
30
25
20
15 -
10 -
5 -
0
PHASE 0 - PRE-MITIGATION
PHASE 1 - SEAL OPENINGS INCLUDING SANITARY PIT
PHASE 0 AVG. 17.5 pCI/l
3/26/87
1
4/2/87
4/9/87 4/16/87
DATE (mm/dd/yy)
4/23/87
4/30/87
Figure A-3. House AR-01 radon concentrations: phase 0 and phase 1
-------
>
--g
X
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a
v-/
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cc
H
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a
ai
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40
35 -
30 -
25
20 -
15 -
10 -
5 -
PHASE 1 - SEAL OPENINGS INCLUDING SANITARY PIT
PHASE 2 - PHASE 1 PLUS DEPRESSURIZE WALLS
PHASE 1 AVO. 17.5 pCI/l
PHASE 2 AVG. 0.44 pCI/l
"T
T
T
9/19/87
9/21/87
9/23/87 9/25/87 9/27/87
DATE (mm/dd/yy)
9/29/87
10/1/87
Figure A-4. House AR-01 radon concentrations: phase 1 and phase 2
-------
TABLE A-3. HOUSE AR-01
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (r>Ci/L)
PHASE
0
0
0
0
1
1
2
2
2
2
2
2
2
2
MONITORING
DETECTOR* PERIOD
CC
CC
AT
CR
CR
CR
CR
AT
AT
AT
CC
AT
AT
AT
10/25/86
12/02/86
02/26/87
03/26/87
04/02/87
09/19/87
09/23/87
09/30/87
02/02/88
03/03/88
03/29/88
03/29/88
06/17/88
11/18/88
- 10/29/86
- 12/06/86
- 04/08/87
- 04/02/87
- 04/29/87
- 09/23/87
- 09/30/87
- 01/09/88
- 03/29/88
- 06/07/88
- 04/01/88
- 06/17/88
- 11/18/88
- 02/28/89
FIRST
BASEMENT FLOOR
19.5
20.0 15.9
11.9
17.5
17.1
17.5
0.4
0.6,0.7 <0. 2, 0.4, 0.7
1.2 <0.5
2.8 2.0
0.6 1.9
4.7 1.6,2.2
5.5 2.1,3.0
<0.3 <0.3,0.4
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
A-8
-------
TABLE A-4. HOUSE AR-04
BUILDING CHARACTERISTICS
STYLE: SPLIT-LEVEL
BASEMENT/SLAB-ON-GRADE CHARACTERISTICS
WALLS:
WALL OPENINGS:
WALL-WALL COMMUNICATION:
FLOOR OPENINGS:
WALL-SUB-SLAB COMMUNICATION:
SUB-SLAB AGGREGATE:
SUB-SLAB COMMUNICATION:
FOOTING DRAINS:
CAPPED BLOCK
MINOR CRACKS
GOOD
LARGE CRACKS
MARGINAL
GRAVELLY SOIL
GOOD
NONE
DIAGNOSTIC RADON MEASUREMENTS*
WATER:
CC SCREENING:
GR SCREENING:
GR FOUNDATION WALLS (AVG):
GR SUB-SLAB:
PUBLIC
24 PCI/L
9 PCI/L
410 PCI/L
126 PCI/L
*CC = CHARCOAL CANISTER, GR = GRAB SAMPLE RADON
A-9
-------
>
o
o
HI
m
*
IT
O
FURNACE
BASEMENT BELOW-GRADE
COMMON BLOCK WALL
WASHER/DRYER
SLAB-ON-GRADE
STAIRS
Figure A-5. House AR-04 basement floor plan
-------
LEGEND
SS1 - BENEATH FLOOR SLAB
W1 - INTERIOR OF NORTH WALL
W2 - INTERIOR OF COMMON WALL
W1 -161 pCi/l
W2 - 667 pCi/l
SS1 -126pCi/l
Figure A-6. House AR-04 diagnostic measurements map
-------
TABLE A-5. HOUSE AR-04
INSTALLED MITIGATION TECHNIQUES
PHASE 1 DEPRESSURIZE SUB-SLAB.
PHASE 2 - PHASE 1 PLUS SEAL OBVIOUS BELOW-GRADE
OPENINGS AND DEPRESSURIZE COMMON BLOCK
WALL.
A-12
-------
40
35
a 30 -
O
a
_
O 25
CC
Z 20
UJ
O
Z
O
z 1S
O
O
UJ
2
UJ
3
CO
10 -
5 -
0 -
3/26/87
PHASE 0 - PRE-MITIGATION
PHASE 1 - DEPRESSURIZE SUB-SLAB
PHASE 2 - PHASE 1 PLUS SEAL
OPENINGS AND DEPRESSURIZE
COMMON BLOCK WALL
PHASE 0 AVQ. 22.8pCI/l
PHASE 1 AVQ. 13.2 pCI/l
T
T
3/30/87 4/3/87 4/7/87
DATE(mm/dd/yy)
4/1 1/87
n 1—
4/15/87
Figure A-7. House AR-04 radon concentrations: phase 0, phase 1, and phase 3
-------
TABLE A-6. HOUSE AR-04
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION
PHASE
0
0
0
0
1
2
2
2
2
2
2
2
2
MONITORING
DETECTOR* PERIOD
CC
CC
AT
CR
CR
CR
AT
AT
AT
CC
AT
AT
AT
11/06/86
12/10/86
02/23/87
03/26/87
04/01/87
04/09/87
09/21/87
02/02/88
03/03/88
03/29/88
03/29/88
06/17/88
11/18/88
- 11/11/86
- 12/14/86
- 04/09/87
- 04/01/87
- 04/09/87,
- 04/15/87
- 02/02/88
- 03/29/88
- 06/07/88
- 04/01/88
- 06/17/88
- 11/18/88
- 02/28/89
BASEMENT
23.9
-
12.6
22.8
13.2
2.2
2.4
0.7
2.7
3.4
3.6
1.9
<0.3,2.2
FIRST
FLOOR
-
11.9
6.6
-
-
-
0.9
<0.5
0.8
1.3
0.5
1.3
0.9
(pCi/Ll
SECOND
FLOOR
-
11.1
-
-
-
-
0.7
<0.5
-
-
2.0
1.1
0.9
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
A-14
-------
TABLE A-7. HOUSE AR-05
BUILDING CHARACTERISTICS
STYLE:
SPLIT-LEVEL
BASEMENT/SLAB-ON-GRADE CHARACTERISTICS
WALLS:
WALL OPENINGS:
WALL-WALL COMMUNICATION:
FLOOR OPENINGS:
WALL-SUB-SLAB COMMUNICATION:
SUB-SLAB AGGREGATE:
SUB-SLAB COMMUNICATION:
FOOTING DRAINS:
CAPPED BLOCK
LARGE CRACKS
GOOD
LARGE CRACKS
MARGINAL
GRAVELLY SOIL
GOOD
NONE
DIAGNOSTIC RADON MEASUREMENTS*
WATER:
CC SCREENING:
GR SCREENING:
GR FOUNDATION WALLS (AVG):
GR SUB-SLAB (AVG):
PUBLIC
32 PCI/L
6 PCI/L
316 PCI/L
536 PCI/L
*CC = CHARCOAL CANISTER, GR = GRAB SAMPLE RADON
A-15
-------
(DHW)
BELOW-GRADE BASEMENT AREA
SLAB-ON-GRADE AREA
Figure A-8. House AR-O5 basement floor plan
-------
>
-si
SS1 - 290 pCi/l x
DHW
SS2 - 782 pCi/l
x
W2 - 586 pCi/l )
W1 - 46 pCi/l
x
Figure A-9. House AR-05 diagnostic measurements map
-------
TABLE A-8. HOUSE AR-05
INSTALLED MITIGATION TECHNIQUES
PHASE 1 DEPRESSURIZE SUB-SLAB.
PHASE 2 - PHASE 1 PLUS DEPRESSURIZE COMMON BLOCK WALL
PHASE 3 PHASE 2 PLUS SEAL BELOW-GRADE OPENINGS
A-18
-------
X
b
a
v_s
Z
O
DC
H
UJ
O
Z
O
O
Z
O
O
<
DC
H
z
UJ
UJ
to
<
03
40
35 -
30
25 -
20 -
15 -
10 -
5 -
PHASE 0 - PRE-MITIGATION
PHASE 1 - DEPRESSURIZE SUB-SLAB
PHASE 2 - PHASE 1 PLUS DEPRESSURIZE COMMON BLOCK WALL
PHASE 0 AVG. 21.3 pCI/l
0 ~ -| I I I I I I I I I I I I I H I I I I I I I | I I I I M I I I I I I I I I I I I I I ITT | I I I I rl I I I I I I I I I I I I I I I I I | I I I I I M I I I II I I I I I I I I I I I | I I I I I I I M I I I I I I I I I I I I 1 1
4/24/87
4/25/87
4/26/87
4/27/87
4/28/87
4/29/87
DATE (mm/dd/yy)
Figure A-10. House AR-05 radon concentrations: phase 0, phase 1, and phase 2
-------
TABLE A-9. HOUSE AR-05
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION fcCi/L)
MONITORING
PHASE DETECTOR* PERIOD
0
0
0
0
1
2
2**
2
3
3
3
3
3
3**
3
CC
cc
AT
CR
CR
CR
AT
AT
AT
CC
CC
AT
AT
AT
AT
10/29/86
11/23/86
02/19/87
04/24/87
04/25/87
04/27/87
09/21/87
02/02/88
03/03/88
03/07/88
03/29/88
03/29/88
03/29/88
06/17/88
11/18/88
- 11/02/86
- 11/28/86
- 04/09/87
- 04/25/87
- 04/27/87
- 04/28/87
- 02/02/88
- 03/29/88
- 06/07/88
- 03/11/88
- 04/01/88
- 06/17/88
- 11/18/88
- 11/18/88
- 02/28/89
FIRST
BASEMENT FLOOR
32.0
23.0
21.7 16.2
21.3
4.2
1.9
10.9 6.1
1.2 0.8
3.7,6.5 1.7
2.4 1.1
2.6 1.2
6.1 1.6
-
16.5
<0.3,1.0 0.9
SECOND
FLOOR
-
14.5
-
-
-
-
5.9
0.7
-
0.9
-
-
2.6
4.7
0.8
* AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
**FAN OFF PART OF THE TIME
A-20
-------
TABLE A-10. HOUSE AR-09
BUILDING CHARACTERISTICS
STYLE:
SPLIT-LEVEL
BASEMENT/SLAB-ON-GRADE CHARACTERISTICS
WALLS:
WALL OPENINGS:
WALL-WALL COMMUNICATION:
FLOOR OPENINGS:
WALL-SUB-SLAB COMMUNICATION:
SUB-SLAB AGGREGATE:
SUB-SLAB COMMUNICATION:
FOOTING DRAINS:
CAPPED BLOCK
LARGE CRACKS
FAIR
MINOR CRACKS
MARGINAL
GRAVELLY SOIL
GOOD
NONE
DIAGNOSTIC RADON MEASUREMENTS*
WATER:
CC SCREENING:
GR SCREENING:
GR FOUNDATION WALLS (AVG):
GR SUB-SLAB (AVG):
PUBLIC
21 PCI/L
16 PCI/L
197 PCI/L
128 PCI/L
*CC = CHARCOAL CANISTER, GR = GRAB SAMPLE RADON
A-21
-------
(V)
r\)
HOLLOW BLOCK WALLS
BASEMENT BELOW-GRADE
COMMON BLOCK WALL
INTERIOR BLOCK PARTITION
FURNACE
WASHER/DRYER
WORKBENCH
STAIRS
TO OUTSIDE
SLAB-ON-GRADE
STAIRS
Figure A-11. House AR-09 basement floor plan
-------
ro
oo
LEGEND
SS1 - BENEATH FLOOR SLAB
SS2 - BENEATH FLOOR SLAB BY EXTERIOR STAIRS '
W1 - INTERIOR OF COMMON WALL BY STAIRS
W2 - INTERIOR OF EAST WALL
W3 - INTERIOR OF PARTITION WALL
W4 - INTERIOR OF NORTH WALL
W5 - INTERIOR OF SOUTH WALL
W2 - 9 pCi/l
W5 - 2 pCi/l
SS1 - 87 pCi/l
W3 - 204 pCi/l
-x-
SS2-168pCi/l
x
W4 - 58 pCi/l
x
Figure A-12. House AR-09 diagnostic measurements map
-------
TABLE A-Il. HOUSE AR-09
INSTALLED MITIGATION TECHNIQUES
PHASE 1 - DEPRESSURIZE SUB-SLAB.
PHASE 2 - PHASE 1 PLUS SEAL OPENINGS AND DEPRESSURIZE
COMMON BLOCK WALL.
PHASE 3 - SEAL OPENINGS (DEACTIVATE SUB-SLAB AND
WALL DEPRESSURIZATION SYSTEMS).
PHASE 4 - PRESSURIZE BASEMENT (INSTALLED, BUT NO
DATA AS OF JUNE 1988)
A-24
-------
z
o
h-
z
ULl
o
z
o
o
z
o
o
<
DC
H
UJ
2
UJ
m
40
35 -
^ 30
O
a
25
20 -
15
10 -
5 -
PHASE 0 - PRE-MITIGATION
PHASE 0 AVG. 22.5pCI/l
WINDOWS OPENED BY HOMEOWNER
0
04/25/87 04/26/87 04/27/87
DATE (mm/dd/yy)
Figure A-13. House AR-09 radon concentrations: phase 0
04/28/87
04/29/87
-------
>
I-J
\
b
Q.
z
o
DC
H
Z
01
o
z
o
o
z
o
Q
<
DC
I-
z
UJ
5
UJ
CD
40
35
30
25 -
20
15 -
10 -
5 ~~
PHASE 1 - DEPRESSURI2E SUB-SLAB
PHASE 2 - PHASE 1 PLUS SEAL OPENINGS AND
DEPRESSURIZE COMMON BLOCK WALL
PHASE 3 - SEAL OPENINGS ONLY
PHASE 1 AVG. 1.4S pCI/l
PHASE 2 AVG. 0.35 pCI/l
Ar?t\
W*—"f^Yg>-
PHASE 3 AVG. 9.9 pCi/l
PHASE 2 AVG. 0.23 pCI/l
11/03/87 11/09/87 11/15/87 11/21/87 11/27/87 12/3/87
DATE (mm/dd/yy)
12/9/87
Figure A-14. House AR-09 radon concentrations: phase 1, phase 2, and phase 3
-------
TABLE A-12. HOUSE AR-09
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION foCi/L)
PHASE
0
0
0
0
1
2
3
2
2
2
2
2
2
2
MONITORING
DETECTOR* PERIOD
CC
CC
AT
CR
CR
CR
CR
CR
AT
AT
AT
CC
AT
AT
11/06/86
12/12/86
02/19/87
04/25/87
11/03/87
11/05/87
11/17/87
11/20/87
01/14/88
03/03/88
03/22/88
03/29/88
06/09/88
11/18/88
- 11/10/86
- 12/16/86
- 04/08/87
- 04/28/87
- 11/05/87
- 11/17/87
- 11/20/87
- 12/09/87
- 03/22/88
- 06/07/88
- 06/09/88
- 04/01/88
- 11/18/88
- 02/28/89
BASEMENT
20.9
-
23.3
22.5
1.5
0.4
9.9
0.2
3.5
1.2,1.2
0.8
2.6
0.9
^
FIRST
FLOOR
—
3.4
4.2
3.8
0.5
0.3
2.2
0.3
0.6
0.4
0.8
1.2
0.8
<0.3
SECOND
FLOOR
—
3.1
-
-
-
-
-
-
1.2
-
0.5
-
0.7
0.4
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
A-27
-------
TABLE A-13. HOUSE AR-16
BUILDING CHARACTERISTICS
STYLE:
CAPE COD
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
SUB-SLAB COMMUNICATION:
FOOTING DRAINS:
POURED CONCRETE
MINOR CRACKS
FRENCH DRAIN, SUMP,
EXPANSION JOINT
GRAVELLY SOIL
MARGINAL
COMPLETE INTERIOR LOOP
DIAGNOSTIC RADON MEASUREMENTS*
WELL WATER:
CC SCREENING:
GR SCREENING (AVG):
GR SLAB-EXPANSION JOINT:
GR FRENCH DRAIN
GR SUMP:
880 PCI/L
33 PCI/L
12 PCI/L
469 PCI/L
12 PCI/L
168 PCI/L
'CC = CHARCOAL CANISTER, GR = GRAB SAMPLE RADON
A-28
-------
4' POURED CONCRETE WALLUPPER 4' WOOD FRAME.
>
(£>
( SUMP V
EXPANSION JOINT -
INTERIOR PERIMETER DRAIN
OPEN DRAIN PIPES
(DHWM
FURNACE
STAIRS
c
i
O
T)
O
ffl
D
O
O
33
m
I
FULL HEIGHT POURED CONCRETE WALL
Figure A-15. House AR-16 basement floor plan
-------
LEGEND
SS1 - INTERIOR OF SUMP
SS2 - BENEATH SUB BY WASTE PIPE
SS3 - IN FRENCH DRAIN
SS4 - BENEATH SLAB AT EXPANSION JOINT
GO
O
SS1 - 168pCi/l
SS4 - 469 pCi/l
SS2-18pCi/l x
SS3-12pCi/l •
Figure A-16. House AR-16 diagnostic measurements map
-------
TABLE A-14. HOUSE AR-16
INSTALLED MITIGATION TECHNIQUES
PHASE 1 DEPRESSURIZE SUMP.
PHASE 2 - SEAL FRENCH DRAIN AND BELOW-GRADE OPENINGS.
(DEACTIVATE SUMP DEPRESSURIZATION SYSTEM)
PHASE 3 COMBINE PHASE 1 AND PHASE 2.
A-31
-------
o
a
N— •
z
o
DC
H
Z
OJ
o
o
o
z
o
o
<
DC
H
z
UJ
5
ai
a)
<
CO
35
30 -
25 -
20 -
15 -
10
5 ~
PHASE 0 - PRE-MITIGATION
PHASE 1 - DEPRESSURIZE SUMP
PHASE 2 - SEAL FRENCH DRAIN AND OPENINGS ONLY
3/17/87
PHASE 0 AVG. IS.SpCI/l
T
3/23/87
T
3/29/87
4/4/87
4/10/87
4/16/87
DATE (mm/dd/yy)
Figure A-17. House AR-16 radon concentrations: phase 0, phase 1, and phase 2
-------
TABLE A-15. HOUSE AR-16
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION fcCi/L)
PHASE
0
0
0
0
1
2
3
3
3
3
3
3
3
3
3
MONITORING
DETECTOR* PERIOD
CC
CC
AT
CR
CR
CR
AT
AT
AT
AT
AT
CC
AT
AT
AT
11/09/86 -
01/16/87 -
02/23/87 -
03/17/87 -
04/01/87 -
04/07/87 -
09/21/87 -
01/09/88 -
02/01/88 -
02/01/88 -
02/26/88 -
03/22/88 -
03/22/88 -
06/08/88 -
11/18/88 -
11/15/86
01/19/87
04/09/87
04/01/87
04/07/87
04/16/87
01/09/88
03/22/88
03/22/88
03/01/89
06/08/88
03/25/88
06/08/88
11/18/88
03/01/89
BASEMENT
32.6
-
10.6
15.5
0.8
5.7
1.7
1.8
1.6
2.2
1.1,1.4
1.5
1.4
3.9
2.1
FIRST
FLOOR
—
23.1
1.6
-
-
-
-
1.6
1.8
0.3
0.4
0.7
0.4
0.8
<0.3
SECOND
FLOOR
—
-
-
-
-
-
0.4
0.9
0.9
0.3
-
-
0.4
0.6
<0.3
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
A-33
-------
TABLE A-16. HOUSE AR-17
BUILDING CHARACTERISTICS
STYLE:
CAPE COD
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
SUB-SLAB COMMUNICATION:
FOOTING DRAINS:
POURED CONCRETE
MINOR CRACKS
FRENCH DRAIN, SUMP,
MINOR CRACKS
GRAVELLY SOIL
MARGINAL
NONE
DIAGNOSTIC RADON MEASUREMENTS*
WELL WATER:
CC SCREENING:
GR SCREENING:
GR SUMP:
GR SUB-SLAB:
737 PCI/L
52 PCI/L
34 PCI/L
114 PCI/L
27 PCI/L
*CC = CHARCOAL CANISTER, GR = GRAB SAMPLE RADON
A-34
-------
POURED CONCRETE WALLS
CO
en
SUMP
t
PERIMETER DRAIN
STAIRS
STAIRWELL
TO GARAGE
Figure A-18. House AR-17 basement floor plan
-------
LEGEND
SS1 - SUMP HOLE
SS2 - BENEATH SLAB NEAR CENTER
GO
CD
SS1 -
SS2 - 27 pCi/l
x
Figure A-19. House AR-17 diagnostic measurements map
-------
TABLE A-17. HOUSE AR-17
BUILDING CHARACTERISTICS
STYLE: CAPE COD
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
SUB-SLAB COMMUNICATION:
FOOTING DRAINS:
POURED CONCRETE
MINOR CRACKS
FRENCH DRAIN, SUMP,
MINOR CRACKS
GRAVELLY SOIL
MARGINAL
NONE
DIAGNOSTIC RADON MEASUREMENTS*
WELL WATER:
CC SCREENING:
GR SCREENING:
GR SUMP:
GR SUB-SLAB:
737 PCI/L
52 PCI/L
34 PCI/L
114 PCI/L
27 PCI/L
-------
OJ
CO
O
Q.
Z
cc
i-
z
111
O
z
O
O
z
O
Q
<
CC
H
Z
UJ
ai
c/)
<
CO
40
35 -
30 -
25 -
20 -
15 -
10 -
5 -
PHASE 0 - PRE-MITIGATION
PHASE 0 AVG. 28.4pCI/l
1 1 1 '—T 1 I I 1 1 1 1 1
3/31/87 4/04/87 4/08/87 4/12/87 4/16/87 4/20/87 4/24/87
4/02/87 4/06/87 4/10/87 4/14/87 4/18/87 4/22/87 4/26/87
DATE (mm/dd/yy)
Figure A-2O. House AR-17 radon concentrations: phase 0
-------
o
a
cc
111
O
Z
O
O
z
O
a
<
cc
h-
z
w
2
ai
oa
40
35
30 -
25 -
20
15 -
10
5 -
PHASE 0 - PRE-MITIGATION
PHASE 1 - DEPRESSURIZE SUB-SLAB
9/21/87
PHASE 0 AVG. 23.6 pCI/l
T
T
9/23/87
9/25/87 9/27/87
DATE (mm/dd/yy)
1
9/29/87
10/01/87
Figure A-2 1. House AR-17 radon concentrations: phase 0 and phase 1
-------
1O
N
O
a
**^
z
O
H
<
cc
H
Z
ai
O
z
O
O
z
O
a
I-
z
UJ
5
UJ
m
8
7 -
4 -
2 -
o
PHASE 2 - PRESSURIZE BASEMENT
PHASE 2 AVG. 0.6 pCI/l
r
2/23/88 2/27/88 3/2/88 3/6/88 3/10/88
2/25/88 2/29/88 3/4/88 3/8/88 3/12/88
DATE (mm/dd/yy)
Figure A-22. House AR-1 7 radon concentrations: phase 2
-------
o
a
s_^
O
I-
<
cc
H
UJ
o
z
o
o
z
o
a
<
cc
H
Z
UJ
UJ
DQ
40
35 -
30
25 -
20 -
15
10 -
PHASE 1 - DEPRESSURI2E SUB-SLAB
PHASE 2 - PRESSURIZE BASEMENT
PHASE 3 - SEAL FRENCH DRAIN AND OPENINGS ONLY
PHASE 4 - PHASE 1 PLUS PHASE 3
PHASE 5 - PHASE 2 PLUS PHASE 3
PHASE 4AVG. 1.8 pCI/l
\
PHASE 3AVG. 9.1 pCI/l
PHASE 6 AVG. O.SpCI/l
inn iiiinii
4/21/88
4/22/88 4/23/88 4/24/88 4/25/88 4/26/88 4/27/88
DATE (mm/dd/yy)
4/28/88
Figure A-23. House AR-17 radon concentrations: phase 3, phase 4, and phase 5
-------
TABLEA-18. HOUSE AR-17
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (DCi/L)
PHASE
0
0
0
0
0
0
1
2
2
2
2
2
4
3
5
5
5
5
MONITORING
DETECTOR* PERIOD
CC
CC
AT
AT
CR
CR
CR
CR
AT
AT
AT
CC
AT
CR
CR
CR
AT
AT
AT
11/10/86
12/12/86
02/19/87
02/23/87
03/31/87
09/21/87
09/23/87
02/24/88
01/14/88
02/26/88
02/29/88
03/22/88
03/22/88
04/21/88
04/24/88
04/25/88
04/27/88
06/08/88
11/21/88
- 11/14/86
- 12/17/86
- 04/01/87
- 04/09/87
- 04/24/87
- 09/23/87
- 09/30/87
- 03/11/88
- 03/22/88
- 06/08/88
- 03/10/88
- 03/25/88
- 06/08/88
- 04/24/88
- 04/25/88
- 04/27/88
- 03/01/89
- 11/21/88
- 03/01/89
BASEMENT
51.8
36.1
16.8
10.6
28.4
23.6
2.2
0.5
1.9
1.1
3.0
2.3
2.8
1.6
9.1
0.5
-
2.2
1.5
FIRST SECOND
FLOOR FLOOR
- -
13.3 11.9
8.6
1.6
-
-
-
-
1.8 1.6
0.4
3.4
1.8 0.7
1.9 1.4
- -
-
- -
0.7
0.7 0.5
1.0 0.9
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
A-42
-------
TABLE A-19. HOUSE AR-19
BUILDING CHARACTERISTICS
STYLE:
COLONIAL
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
SUB-SLAB COMMUNICATION:
FOOTING DRAINS:
POURED CONCRETE
CRACKS, PENETRATIONS
LARGE CRACKS
GRAVELLY SOIL
GOOD
NONE
DIAGNOSTIC RADON MEASUREMENTS*
WELL WATER:
CC SCREENING:
GR SCREENING:
GR WELL SLEEVE:
GR SUB-SLAB:
501 PCI/L
35 PCI/L
35 PCI/L
275 PCI/L
550 PCI/L
*CC = CHARCOAL CANISTER, GR = GRAB SAMPLE RADON
A-43
-------
POURED CONCRETE WALLS
STAIRS
Figure A-24. House AR-19 basement floor plan
-------
LEGEND
SS1 - BENEATH FLOOR SLAB IN CENTER
W1 - CRACK AROUND WELL SLEEVE
>
en
W1-330pCi/l
SS1-706pCi/l
Figure A-25. House AR-19 diagnostic measurements map
-------
TABLE A-20. HOUSE AR-19
INSTALLED MITIGATION TECHNIQUES
PHASE 1 DEPRESSURIZE SUB-SLAB
A-46
-------
50
40 -
O
a
Z
O
p 30 -
DC
J-
Z
O
z
O
O
z
O
a
LU
5
UJ
CO
20 -
10 -
0 -TTTTT
PHASE 0 - PRE-MITIGATION
TTIT11T11 [I 11 11 Illl MITT 111 M III 111111 III 1'ITI III III III I IT 1TTTI11II I'll H H I 1111 M 11 11 I M H ITTTT HI Tl 11111(11 inTfmi I I III1 II I IT | !|T I U I 11 11 I'l III I ITfri 11 [
4/24/87 4/25/87 4/26/87 4/27/87 4/28/87 4/29/87 4/30/87 5/1/87
DATE (mm/dd/yy)
Figure A-26. House AR-19 radon concentrations: phase 0
-------
TABLE A-21, HOUSE AR-19
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION
PHASE DETECTOR*
MONITORING
PERIOD
BASEMENT
FIRST SECOND
FLOOR FLOOR
0
0
0
1
1
1
1
1
1
1
cc
cc
AT
AT
AT
AT
CC
AT
AT
AT
11/14/86
12/17/86
02/20/87
09/21/87
02/01/88
03/01/88
03/22/88
03/22/88
06/08/88
09/27/88
- 11/18/86
- 12/21/86
- 04/01/87
- 02/01/88
- 03/22/88
- 06/08/88
- 03/25/88
- 06/08/88
- 09/27/88
- 03/01/88
34.7
-
12.3
29.1
27.4
33.8
26.1
19.4
11.0
22.2
—
7
2.2
-
3.3
<3.0
0.8
<0.4
0.6
1.0
—
•>
-
-
5.9
-
-
<0.4
0.7
0.9
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
A-48
-------
TABLE A-22, HOUSE AR-20
BUILDING CHARACTERISTICS
STYLE:
RANCH
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
SUB-SLAB COMMUNICATION:
FOOTING DRAINS:
POURED CONCRETE
MINOR CRACKS
FRENCH DRAIN,
SUMP, MINOR CRACKS
GRAVELLY SOIL
GOOD
COMPLETE INTERIOR LOOP
DIAGNOSTIC RADON MEASUREMENTS*
WELL WATER:
CC SCREENING:
GR SCREENING:
GR FOUNDATION WALL CRACK:
GR SUB-SLAB:
GR FRENCH DRAIN
GR FOOTING DRAIN
348 PCI/L
61 PCI/L
43 PCI/L
37 PCI/L
49 PCI/L
104 PCI/L
320 PCI/L
*CC = CHARCOAL CANISTER, GR = GRAB SAMPLE RADON
A-49
-------
POURED CONCRETE WALLS
>
o
WORKSHOP
STAIRS
SUMP
DRAIN
t
Figure A-27. House AR-20 basement floor plan
-------
>
cn
LEGEND
SS1 - SUMP HOLE
SS2 - FRENCH DRAIN EAST SIDE
SS3 - BENEATH FLOOR SLAB IN WORKSHOP
SS4 - IN FOOTER DRAIN
W1 - CRACK IN EAST WALL
TKirrtrojai
x SS3 - 49 pCi/l
SS1 - 34 pCi/l
SS4 - 320 pCi/l
SS2-104pCi/l
\
W1 - 37 pCi/l
Figure A-28. House AR-20 diagnostic measurements map
-------
TABLE A-23. HOUSE AR-20
INSTALLED MITIGATION TECHNIQUES
PHASE 1 - DEPRESSURIZE SUMP AND INTERIOR FOOTING DRAIN.
PHASE 2 SEAL FRENCH DRAIN AND BELOW-GRADE OPENINGS.
(DEACTIVATE SUMP DEPRESSURIZATION SYSTEM)
PHASE 3 COMBINE PHASE 1 AND PHASE 2.
A-52
-------
60
o
a
Z
O
H
UJ
O
Z
o
o
Z
o
a
<
oc
h-
z
ai
5
UJ
OQ
50 -
40 -
30 -
20
10
PHASE 0 - PRE-MITIGATION
PHASE 1 - DEPRESSURIZE SUMP
PHASE 2 - SEAL FRENCH DRAIN AND OPENINGS
1 1 1 1 1 1 I I
3/18/87 3/22/87 3/26/87 3/30/87 4/3/87
DATE (mm/dd/yy)
I I 1 1 r~
4/7/87 4/11/87 4/15/87
Figure A-29. House AR-20 radon concentrations: phase 0, phase 1 and phase 2
-------
TABLE A-24. HOUSE AR-20
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (pCi/L)
PHASE
0
0
0
0
1
2
3
3
3
3
3
3
3
MONITORING
DETECTOR* PERIOD
CC
CC
AT
CR
CR
CR
AT
AT
AT
CC
AT
AT
AT
11/16/86
12/12/86
02/19/87
03/18/87
03/26/87
04/08/87
09/21/87
01/09/88
02/29/88
03/22/88
03/22/88
06/08/88
11/17/88
- 11/20/86
- 12/16/86
- 04/14/87
- 03/26/87
- 04/08/87
- 04/15/87
- 01/09/88
- 03/22/88
- 06/08/88
- 03/25/88
- 06/08/88
- 11/17/88
- 03/01/89
BASEMENT
60.6
-
24.6
35.7
2.3
9.3
6.4
8.3
5.5
7.3
5.4
7.5
5.7
FIRST
FLOOR
-
19.4,20.5
8.3
-
-
-
0.8,1.2
1.8,2.5
2.0
0.4
0.9,1.2
1.5,1.7
0.9,1.0
* AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
A-54
-------
TABLE A-25. HOUSE OP-01
BUILDING CHARACTERISTICS
STYLE:
COLONIAL
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
WALL-WALL COMMUNICATION:
FLOOR OPENINGS:
WALL-SUB-SLAB COMMUNICATION:
SUB-SLAB AGGREGATE:
SUB-SLAB COMMUNICATION:
FOOTING DRAINS:
OPEN TOP BLOCK
(TO ATTIC)
HOLES AND CRACKS
FAIR
LARGE CRACKS
NONE
SANDY SOIL
MARGINAL
NONE
DIAGNOSTIC RADON MEASUREMENTS*
WELL WATER:
AT SCREENING:
GR SCREENING:
GR FOUNDATION WALLS:
GR SUB-SLAB:
120 PCI/L
30 PCI/L
26 PCI/L
122 PCI/L
737 PCI/L
*CC = CHARCOAL CANISTER, GR = GRAB SAMPLE RADON
A-55
-------
TABLE A-26. HOUSE OP-01
INSTALLED MITIGATION TECHNIQUES
PHASE 1 DEPRESSURIZE SUB-SLAB WITH REGENERATIVE FAN
AND FOUR PERIMETER SUCTION POINTS.
PHASE 2 DEPRESSURIZE SUB-SLAB WITH CENTRIFUGAL FAN
AND ONE CENTRAL SUCTION POINT.
PHASE 3 DEPRESSURIZE BACK WALL WITH CENTRIFUGAL FAN
AND ONE SUCTION POINT. (DEACTIVATE SUB-
SLAB DEPRESSURIZATION)
PHASE 4 - PHASE 2 PLUS PHASE 3.
A-56
-------
>
I
Oi
o
a
*•«*
Z
O
OC
z
UJ
O
z
O
O
z
O
Q
<
OC
h-
i
UJ
-------
L/l
00
O
0.
oc
H
Z
UJ
O
Z
O
O
Z
O
Q
<
DC
\-
Z
UJ
5
UJ
CO
40
35 -
30
25 -
20
15 -
10
5 -
PHASE 1 - DEPRESSURIZE SUB-SLAB WITH REGENERATIVE FAN,
FOUR PERIMETER SUCTION POINTS
1/26/87
PHASE 1 AVG. 1 1.0 pCI/l
\f-W
v
vV
I
1/28/87
I
1/30/87
I
2/1/87
2/3/87
DATE (mm/dd/yy)
Figure A-31. House OP-01 radon concentrations: phase 1
2/5/87
-------
Ol
VO
\
O
Z
UJ
O
Z
O
O
Z
O
Q
<
CC
h-
z
UJ
UJ
CO
40
35 -
30 -
2 25
20
15 -
10
5 -
PHASE 2 - DEPRESSURIZE SUB-SLAB WITH CENTRIFUGAL FAN,
ONE CENTRAL SUCTION POINT
PHASE 2 AVG. 14.3pCI/l
1 1 1 1 1 1 1 1 1 1 1 1 1 1
2/19/87 2/21/87 2/23/87 2/25/87 2/27/87 3/1/87 3/3/87 3/5/87
2/20/87 2/22/87 2/24/87 2/26/87 2/28/87 3/2/87 3/4/87 3/6/87
DATE (mm/dd/yy)
Figure A-32. House OP-01 radon concentrations: phase 2
-------
ON
O
o
a
<^>
Z
O
h-
<
DC
H
Z
UJ
o
z
o
o
z
o
a
<
cc
h-
z
UJ
s
UJ
CO
40 -
35 -
30 -
25 -
20 -
15 -
10
PHASE 2 - DEPRESSURIZE SUB-SLAB WITH CENTRIFUGAL FAN
PHASE 3 - DEPRESURRIZE BACK WALL WITH CENTRIFUGAL FAN
PHASE 2 AVG. 4.7 pCI/l
PHASE 2 AVG. 7.3 pCI/l
OPEN BASEMENT WINDOWS
AVG. 0.7 pCI/l
o -t-*"---'-, • • f——"|- •• - -^ , r 1 1 1 r— 1
9/2/87 9/16/87 9/30/87 10/14/87 10/28/87
9/9/87 9/23/87 10/7/87 10/21/87
11/11/87
11/4/87 11/18/87
DATE (mm/dd/yy)
Figure A-33. House OP-01 radon concentrations: phase 2 and phase 3
-------
TABLE A-27. HOUSE OP-01
INTEGRATED RADON CONCENTRATIONS
PHASE
0
0
0
0
0
0
0
0
0
1
1
1
2
2
3
3
2
4
4
4
4
4
4
MONITORING
DETECTOR* PERIOD
AT
AT
GR
GR
GR
AT
CR
CC
CR
CR
CC
CR
CR
CR
CR
CR
AT
CR
AT
CC
AT
AT
AT
AT
12/09/86
01/16/86
02/26/86
10/13/86
11/11/86
11/11/86
01/15/87
01/15/87
01/15/87
01/22/87
01/23/87
01/26/87
02/19/87
09/02/87
09/30/87
10/14/87
10/14/87
10/22/87
02/09/88
03/08/88
03/08/88
03/12/88
06/21/88
11/29/88
- 01/07/87
- 02/26/86
(HOUSE OPEN)
- 01/15/87
- 01/19/87
- 01/19/87
- 01/21/87
- 01/26/87
- 01/26/87
- 02/04/87
- 03/05/87
- 09/30/87
- 10/14/87
- 10/22/87
- 02/09/88
- 11/18/87
- 03/12/88
- 03/12/88
- 06/15/88
- 06/21/88
- 11/29/88
- 03/07/89
RADON CONCENTRATION (DCi/L)
FIRST SECOND
BASEMENT FLOOR FLOOR
14.6 7.8
29.7 11.8 12.6
16.9
2.5
25.9
13.1,16.8 7.1 6.9
19.3
15.7,16.2 - 6.9
20.6
18.0
11.9,12.8 - 3.5,3.6
11.0
14.3
0.7
4.7
2.8
3.3 2.9 1.1
7.3
2.5,3.5 1.6
3.3 0.9 1.0
3.6 0.7 1.7
2.3 1.0 0.5
2.5 1.1 1.3
2.8 1.3 1.1
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
GR = GRAB SAMPLE RADON
A-61
-------
HOLLOW-CORE CONCRETE BLOCK WALLS
>
CD
WET SINK
LAUNDRY AREA
DRYER
WASHER
LAUNDRY TABLE
INTERIOR PARTITION
CLOSET
OIL TANK
Figure A-34. House OP-01 basement floor plan
TV/PLAYROOM AREA
STAIRS
HOME MAINTENANCE AREA
BOILER
I
O
111
OQ
^
(X
O
-------
LEGEND
W1 - INTERIOR OF BACK WALL
SS1 - SUB-SLAB SW CORNER
O)
CO
W1 -122.5pCi/l
SS1 - 737 pCi/l
Figure A-35. House OP-01 diagnostic measurements map
-------
TABLE A-28. HOUSE OP-03
BUILDING CHARACTERISTICS
STYLE:
BI-LEVEL
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
WALL-WALL COMMUNICATION:
FLOOR OPENINGS:
WALL-SUB-SLAB COMMUNICATION:
SUB-SLAB AGGREGATE:
SUB-SLAB COMMUNICATION:
FOOTING DRAINS:
BLOCK AND POURED
CONCRETE
LARGE HOLES
GOOD
MINOR CRACKS
NONE
SANDY SOIL
MARGINAL
EXTERIOR THREE SIDES
DIAGNOSTIC RADON MEASUREMENTS*
WELL WATER:
CC SCREENING:
GR SCREENING (AVG):
GR FOUNDATION WALLS:
GR SUB-SLAB:
GR WELL SLEEVE:
380,000 PCI/L
52 PCI/L
29 PCI/L
68 PCI/L
20 PCI/L
434 PCI/L
'CC = CHARCOAL CANISTER, GR = GRAB SAMPLE RADON
A-64
-------
BELOW-GRADE SLAB
m
5
CO
UJ
Q
<
DC
CD
UJ
CO
CD
Ol
BEDROOM
CLOSET
BATHROOM
FURNACE ROOM
FAMILY ROOM
CLOSET
UNDER
STAIRS
GARAGE
CO
m
1
CD
LAUNDRY ROOM
STAIRS
SLAB-ON-GRADE
Figure A-36. House OP-03 lower level floor plan
-------
LEGEND
SS1 - BENEATH FLOOR SLAB IN CLOSET
W1 - INTERIOR OF WALL IN UTILITY ROOM
W2 - WELL SLEEVE IN UTILITY ROOM
A1 - BATHROOM AMBIENT AIR
A2 - BATHROOM AMBIENT AIR AFTER
5 MINUTE SHOWER
CD
CD
x A1 - 31 pCi/l
x A2 - 601 pCi/l
-* x-
W2 - 434 pCi/l
W1 - 68 pCi/l
SS1 - 20 pCi/l
x
Figure A-37. House OP-03 diagnostic measurements map
-------
TABLE A-29. HOUSE OP-03
INSTALLED MITIGATION TECHNIQUES
PHASE 1 - FILTER RADON FROM WELL WATER WITH
CHARCOAL.
PHASE 2 - PHASE 1 PLUS SEAL OBVIOUS OPENINGS
AND DEPRESSURIZE SUB-SLAB.
PHASE 3 PHASE 2 PLUS AERATE RADON FROM WELL
WATER WITH TWO-STAGE AERATION SYSTEM.
A-67
-------
O\
00
O
Q.
v^
z
DC
h-
z
ai
o
z
o
o
z
o
Q
<
cc
o
o
DC
X
t-
<
m
300
280
260
240
220 H
200
180
160 H
140
120 H
100
80 -
60 -
40 -
20 -
0 -
PHASE 0 - PRE-MITIGATION
SPIKES DUE TO WATER USAGE
T
T
T
T
T
10/22/87 10/28/87 11/03/87 11/09/87
DATE (mm/dd/yy)
T
1 1/15/87
11/21/87
Figure A-38. House OP-03 bathroom radon concentrations: phase 0
-------
o
z
g
h-
oc
I-
z
UJ
o
z
o
o
z
o
o
o
o
cc
X
H
CQ
300
280
260
240
220
200
180
160
140
120
100
80
60
40
20
PHASE 1 - FILTER WATER WITH CHARCOAL
PHASE 1 AVG. 24.8 pCI/l
0 ~~ mi n n M in i n n n ii i|i ii mill ii
12/04/87 12/05/87 12/06/87 12/07/87 12/08/87 12/09/87 12/10/87 12/11/87
DATE (mm/dd/yy)
Figure A-39. House OP-03 bathroom radon concentrations: phase 1
-------
500 -
b
a
^_^
Z
O
DC
I-
z
at
o
z
o
o
z
o
a
<
cc
2
o
o
DC
<
u.
400
300 -
200
100
0
PHASE 0 - PRE-MITIGATION
SPIKES PROBABLY DUE TO
WATER USAGE
PHASE 0 AVG. 21.9 pCI/l
T
T
T
T
9/3/87 9/9/87 9/15/87 9/21/87
DATE (mm/dd/yy)
Figure A-4O. House OP-03 family room radon concentrations: phase 0
1
9/27/87
10/3/87
-------
N.
o
Q.
SwX
Z
O
cc
I-
z
UJ
o
Z
o
o
Z
o
o
<
cc
o
o
cc
>-
500
400 -
300
200 -
100 -
PHASE 1 - FILTER WATER WITH CHARCOAL
PHASE 2 - PHASE 1 PLUS SEAL OPENINGS AND DEPRESSURIZE SUB-SLAB
PHASE 2 AVG. 8.8 pCI/l
3/9/88
3/10/88
3/11/88
DATE (mm/dd/yy)
3/12/88
3/13/88
Figure A-41. House OP-03 family room radon concentrations: phase 2
-------
>
-~l
K)
o
a.
*— '
Z
O
DC
H
UJ
O
Z
o
o
Z
o
a
<
cc
o
o
CC
500
400 -
300 H
200 H
100
PHASE 3 - PHASE 1 PLUS PHASE 2 PLUS AERATE WATER
0
4/13/88
PHASE 3 AVG. 3.0 pCI/l
Trrrrrurniwiiun|iiirnTiTiiiiiinrniii|iiiiiiiiiiiiiiniM
4/15/88
IIMIIIIIIIUIHMUIMII|M
4/17/88
tnii i ii 11 ii i M i ii MI i im i ii ii] MI ii MUM H
4/19/88
IIIIIIM|IIIMIMIMMIIIIIUIIl|H|]||ll(MllUlUHfll|lII(TTTTnTnmT1
4/21/88 4/23/88
DATE (mm/dd/yy)
Figure A-42. House OP-03 family room radon concentrations: phase 3
-------
X
o
a
Z
O
H
cc
h-
2
HI
u
Z
o
0
Z
0
a
oc
o
0
oc
i
h-
CQ
ouu —
280 -
260 -
240 -
220 -
200 -
180 -
160 -
140 -
120 -
100 -
80 -
60 -
40 -
20 -
PHASE 3 - PHASE 1 PLUS PHASE 2 PLUS AERATE WATER
PHASE 3 AVG. 6.0 pCI/l
i
SPIKES DUE TO HEAVY WATER USAGE 1
\
\
\
\ C>
1 A 1
A_ ^ A .. * -A _
^ ' ^ "•-*" ^ v ' X— / " ~^~~^_ x7 "^-^ v —
4/26/88
DATE (mm/dd/yy)
4/28/88
4/30/88
Figure A-43. House OP-03 bathroom radon concentrations: phase 3
-------
TABLE A-30. HOUSE OP-03
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (pCi/L)
PHASE
0
0
0
0
0
0
0
0
0
0
0
0
1
2
3
3
3
3
MONITORING
DETECTOR* PERIOD
GR
CC
GR
GR
GR
GR
AT
AT
CR
CC
CR
CR
CR
AT
AT
CR
AT
CR
AT
AT
AT
09/30/86
09/30/86
11/10/86
11/10/86
11/10/86
11/10/87
11/10/86
12/10/86
01/15/87
01/15/87
01/22/87
09/03/87
12/04/87
01/15/88
03/08/88
03/10/88
03/12/88
04/13/88
04/14/88
06/21/88
11/30/88
- 10/04/86
- 01/15/87
- 01/07/87
- 01/22/87
- 01/22/87
- 01/26/87
- 09/30/87
- 12/10/87
- 03/12/88
- 06/14/88
- 03/12/88
- 04/14/88
- 04/22/88
- 06/21/88
- 11/30/88
- 03/07/89
FIRST SECOND
LEVEL LEVEL
57.0
51.6
25.7
21.6 17.8
30.5
37.5
19.8,21.0, 19.8
23.8,29.1
30.4 18.1
18.5
20.3,22.5 19.6
18.0
21.9
24.8
6.1,6.8 5.8,6.4
4.2,4.3 2.7
7.2,8.8 4.2
9.2 5.1
3.0
4.0 2.3
4.7 2.0
5.4 5.3
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
GR = GRAB SAMPLE RADON
A-74
-------
TABLE A-31. HOUSE OP-05
BUILDING CHARACTERISTICS
STYLE:
RANCH
FULL CRAWL SPACE CHARACTERISTICS
WALLS:
WALL OPENINGS:
WALL-WALL COMMUNICATION:
FLOOR OPENINGS:
WALL-SUB-SLAB COMMUNICATION:
SUB-SLAB AGGREGATE:
SUB-SLAB COMMUNICATION:
FOOTING DRAINS:
OPEN TOP BLOCK
LARGE OPENINGS
GOOD
BEDROCK
OUTCROPPING
NONE
BEDROCK
NONE
NONE
DIAGNOSTIC RADON MEASUREMENTS*
WELL WATER:
CC SCREENING:
CC CRAWL SPACE:
GR CRAWL SPACE:
GR FOUNDATION WALLS:
GR FLUX FROM BEDROCK:
AT ROCK FISSURE:
AT WELL SLEEVE:
245,000 PCI/L
180 PCI/L
567 PCI/L
281 PCI/L
384 PCI/L
129 PCI/M2S
440 PCI/L
3,700 PCI/L
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER, GR = GRAB SAMPLE RADON
A-75
-------
HOLLOW CORE CONCRETE BLOCK WALLS
Figure A-44. House OP-50 cruwlspuce floor plnn
-------
LEGEND
F 1 - INFLUX FROM ROCK OUTCROPPING.TIME:0
F2 - INFLUX FROM ROCK OUTCROPPING.TIME:* 1 5 WIN.
F3 - INFLUX FROM ROCK OUTCHOPPING.TIME:»30 MIN.
F4 - INFLUX FROM ROCK OUTCROPPING.TIME:»4B MIN.
W 1 - PIPE PENETRATION EAST WALL
W2 - WELL SLEEVE EAST WALL
F1 - 150.4pCI/l
F2 - 382.0 pCI/l
F3 - 673.9 pCI/l
F4- 747.8 pCI/l
W1 - 383.7 pCI/l
Figure A-45. House OI'-OS diagnostic ineasureincnts m;ip
-------
TABLE A-32. HOUSE OP-05
INSTALLED MITIGATION TECHNIQUES
PHASE 1 COVER AND DEPRESSURIZE CRAWL SPACE
ROCK OUTCROPPING.
PHASE 2 - PHASE 1 PLUS DEPRESSURIZE CRAWL SPACE
WALLS.
PHASE 3 PHASE 2 PLUS AERATE RADON FROM WELL
WATER WITH TWO-STAGE AERATION SYSTEM.
A-78
-------
600
o
a
**^r
z
DC
F-
Z
ai
o
z
o
o
z
o
o
<
DC
DC
O
o
V)
DC
LL
500 -
400 -
300 -
200
100
0
PHASE 0 - PRE-MITIGATION
T
T
T
T
10/14/87 10/22/87 10/30/87 11/7/87 11/15/87 11/23/87 12/1/87
10/18/87 10/26/87 11/3/87 11/11/87 11/19/87 11/27/87 12/5/87
DATE (mm/dd/yy)
Figure A-46. House OP-05 first floor radon concentraions: phase 0
-------
600
oo
o
O
a
V -- *
Z
O
H
z
ai
o
z
o
o
z
o
o
<
cc
UJ
o
cc
o
500
400 -
300
200
100
PHASE 1 - COVER AND DEPRESSURIZE CRAWL SPACE ROCK
OUTCROPPINGS
PHASE 1 AVG. 44.2 pCI/l
1/15/88
\
1/17/88
1
1/19/88
n
1/21/88
1/23/88
1
1/25/88
1/27/88
DATE (mm/dd/yy)
Figure A-47. House OP-05 crawl space radon concentrations: phase 1
-------
>
oo
O
Q.
*^*/
Z
O
\-
<
cc
\-
z
HI
O
Z
O
O
Z
O
O
<
cc
UJ
O
<
cc
O
600 -
500 -
400 -
300
200 -
100 -
PHASE 1 - COVER AND DEPRESSURIZE CRAWL SPACE ROCK
OUTCROPPINGS
PHASE 2 - PHASE 1 PLUS DEPRESSURIZE WALLS
PHASE 2 AVG. 6.5 pCI/l
,r\~ -A
T
T
T
T
I
3/9/88 4/15/88 3/21/88 3/27/88 4/2/88 4/8/88
3/12/88 3/18/88 3/24/88 3/30/88 4/5/88 4/11/88
DATE (mm/dd/yy)
Figure A-48. House OP-05 crawl space radon concentrations: phase 2
-------
600
>
oo
O
Q.
Z
O
h-
-------
TABLE A-33. HOUSE OP-05
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (pCi/L)
MONITORING
PHASE DETECTOR* PERIOD
0
0**
0**
0
0
0
0
0
0
0
0
0
0
0+
0
1
1
2
3
3
3
3
GR
GR
CC
CC
GR
AT
AT
CC
CC
CR
CC
CR
CC
CR
CR
CR
AT
AT
CR
CR
AT
AT
AT
04/23/86
04/23/86
04/23/86
09/06/86
11/10/86
11/10/86
12/09/86
01/16/87
01/16/87
01/20/87
01/20/87
01/23/87
01/23/87
08/26/87
10/14/87
01/15/88
01/15/88
03/08/88
03/09/88
04/14/88
04/14/88
06/21/88
11/30/88
- 04/26/86
- 09/10/86
- 01/16/87
- 01/07/87
- 01/20/87
- 01/20/87
- 01/23/87
- 01/23/87
- 01/26/87
- 01/26/87
- 09/02/87
- 12/04/87
- 01/26/88
- 03/12/88
- 06/15/88
- 04/10/88
- 04/29/88
- 06/21/88
- 11/30/88
- 03/07/89
FIRST
CRAWL SPACE FLOOR
567.0
151.0
154.0
-
280.9
-
275.0
364.0
-
-
-
-
232.0
71.6
-
44.2
-
4.0
8.5
-
8.6
13.7
13.1
120.0,191.0
-
33.6
178.1,179.9
-
157.7, 172.0,178.9
166.0,178.0
150.7
147.8,165.8
161.6
146.3
97.8
104.4,122.6
1.6
160.3
-
10.8,12.7
4.0,8.0
-
1.0
1.3,1.7
1.7,1.0
1.2,0.9
* AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON,
GR = GRAB SAMPLE RADON
**CRAWL SPACE NATURALLY VENTED
+ CRAWL SPACE VENTED WITH FAN
A-83
-------
HOLLOW-CORE CONCRETE BLOCK WALLS
>
oo
UNCAPPED CRAWL SPACE WITH EXPOSED ROCKS
WORKBENCH
STAIRS
FLOOR DRAIN
BOILER
Figure A-50. House OP-06 basement floor plan
-------
LEGEND
SS1 - SUB-SLAB NE CORNER
W1 - INTERIOR OF WALL NE CORNER
A1 - CRAWL SPACE AMBIENT AIR
00
Ol
A1 -37.8pCi/l
W1-104.6pCi/l
SS1 - 56.6 pCi/l
Figure A-51. House OP-06 diagnostic measurements
-------
TABLE A-34. HOUSE OP-06 (CONTROL)
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATIONS (pCi/L)
PHASE
0
0
0
0
0
0
0
0
0
0
0
0
0
MONITORING
DETECTOR* PERIOD
CC
CC
AT
AT
CR
CR
AT
AT
CC
AT
AT
AT
AT
04/23/86
08/28/86
11/12/86
12/10/86
01/16/87
01/16/87
02/09/88
02/09/88
03/09/88
03/09/88
03/12/88
03/12/88
11/30/88
- 04/26/86
- 09/01/86
- 01/16/87
- 01/08/87
- 01/17/87
- 01/26/87
- 03/12/88
- 06/21/88
- 03/12/88
- 06/15/88
- 06/21/88
- 03/07/89
- 03/07/89
BASEMENT
26.2
26.1
23.4
23.8
20.7
24.4,26.8
12.0
-
19.2
21.4
22.7
21.7
16.0
FIRST SECOND
FLOOR FLOOR
7.8
7.8
11.4
5.3
-
7.5
5.2
4.1
4.7 4.7
6.0
5.1
3.8
6.3
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
A-86
-------
TABLE A-35. HOUSE OP-09
BUILDING CHARACTERISTICS
STYLE:
COLONIAL
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
SUB-SLAB COMMUNICATION:
FOOTING DRAINS:
POURED CONCRETE
LARGE OPENINGS
LARGE CRACKS
SANDY SOIL
MARGINAL
NONE
DIAGNOSTIC RADON MEASUREMENTS*
WELL WATER: 450 PCI/L
CC SCREENING: 21 PCI/L
GR SCREENING: 29 PCI/L
GR FOUNDATION WALLS (AVG): 80 PCI/L
GR SUB-SLAB: 820 PCI/L
*CC = CHARCOAL CANISTER, GR = GRAB SAMPLE RADON
A-87
-------
POURED CONCRETE WALLS
CO
CO
STAIRS
WORKBENCH
LOCATION 1
Figure A-52. House OP-09 basement floor plan
-------
LEGEND
SS1 - BENEATH SLAB SE SELECTION
W1 - CRACK IN WEST WALL
W2 - CRACK IN SOUTH WALL
C W2-130pCi/l
00
CO
X
W1 - 29 pCi/l
SS1 - 820 pCi/l
X
Figure A-53. House OP-09 diagnostic measurements map
-------
TABLE A-36. HOUSE OP-09
INSTALLED MITIGATION TECHNIQUES
PHASE 1 PARGET INTERIOR CONCRETE BASEMENT WALLS
WITH SURFACE BONDING CEMENT AND SEAL
FLOOR CRACKS.
PHASE 2 PHASE 1 PLUS DEPRESSURIZE SUB-SLAB WITH
REGENERATIVE FAN.
A-90
-------
50
\
O
Q.
SHI/
Z
O
p
<
cc
Z
UJ
O
Z
O
O
I
<
cc
H
z
LU
UJ
V)
<
CO
40 -
30 -
20 -
10
PHASE 0 - PRE-MITIGATION
PHASE 1 - PARGE INTERIOR
CONCRETE WALLS
PHASE 0 AVG. 23.5pCi/l
PHASE 1 AVG. 14.7 pCI/l
BASEMENT WINDOWS OPEN
1/16/87
1/18/87
1
1/20/87
\ 1
1/22/87
DATE (mm/dd/yy)
I
1/24/87
I
1/26/87
1/28/87
Figure A-54. House OP-09 radon concentrations: phase 0 and phase 1
-------
60 -
O
Z
o
H
oc
H
Z
ai
o
z
o
o
z
o
Q
CC
H
Z
LU
CD
50 -
40
30
20 -
10
0
PHASE 1 - PARGE INTERIOR
CONCRETE WALLS
PHASE 2 - PHASE 1 PLUS
DEPRESSURIZE SUB-SLAB
USING REGENERATIVE
BLOWER
PHASE 1 AVG. 1 1.4 pCI/l
PHASE 2 AVG. 3.4 pCI/l
T
T"
T
~T
T
T
~T
2/13/87 2/15/87 2/17/87 2/19/87 2/21/87 2/23/87
2/14/87 2/16/87 2/18/87 2/20/87 2/22/87 2/24/87
DATE (mm/dd/yy)
Figure A-55. House OP-09 radon concentrations: phase 1 and phase 2
-------
TABLE A-37. HOUSE OP-09
INTEGRATED RADON CONCENTRATIONS
PHASE
0
0
0
0
0
0
0
0
1
1
1
2
2
2
2
2,
2
2
2
MONITORING
DETECTOR* PERIOD
CC
GR
AT
AT
CR
CC
CC
CR
CR
CR
CR
CR
AT
AT
AT
AT
AT
AT
AT
08/29/86
11/12/86
11/12/86
12/10/86
01/16/87
01/16/87
01/19/87
01/19/87
01/21/87
01/27/87
02/12/87
02/17/87
02/23/87
02/23/87
10/14/87
01/15/88
04/28/88
06/15/88
11/30/88
- 09/02/86
- 01/16/87
- 01/07/87
- 01/19/87
- 01/19/87
- 01/21/87
- 01/21/87
- 01/26/87
- 02/12/87
- 02/17/87
- 02/24/87
- 01/05/88
- 03/07/89
- 01/15/88
- 06/21/88
- 06/15/88
- 11/30/88
- 03/07/89
RADON CONCENTRATION (l
-p • l-r \
FIRST SECOND
BASEMENT FLOOR FLOOR
20.7
29.4 6.6
20.1,20.5 3.6
26.6 3.1
22.9
24.1
17.5,17.9 3.3
23.5
14.7
14.1
11.4
3.4
2.3 0.9
1.6
0.4
1.0,1.2 0.2,0.5
1.9 0.8
1.3 0.6
0.6 0.7
-
-
-
-
-
-
-
-
-
-
-
-
0.9
-
0.4
0.4
-
0.5
0.7
AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
GR = GRAB SAMPLE RADON
A-93
-------
TABLE A-38. HOUSE OP-13
BUILDING CHARACTERISTICS
STYLE:
BI-LEVEL
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
WALL-WALL COMMUNICATION:
FLOOR OPENINGS:
WALL-SUB-SLAB COMMUNICATION:
SUB-SLAB AGGREGATE:
SUB-SLAB COMMUNICATION:
FOOTING DRAINS:
OPEN TOP BLOCK
MINOR CRACKS
MARGINAL
MINOR CRACKS, DRAIN
MARGINAL
GRAVEL
GOOD
EXTERIOR THREE SIDES
DIAGNOSTIC RADON MEASUREMENTS*
WELL WATER:
CC SCREENING:
GR SCREENING:
GR FOUNDATION WALLS:
GR FLOOR DRAIN:
6,500 PCI/L
25 PCI/L
16 PCI/L
27 PCI/L
183 PCI/L
*CC = CHARCOAL CANISTER, GR = GRAB SAMPLE RADON
A-94
-------
ON-GRADE CONCRETE BLOCK WALL
o
3
> UJ
-------
LEGEND
SSI -FLOOR DRAIN
W1 • INTERIOR OF BLOCK WALL
CD
CD
SS1-183 pCI/l
W1-26.9 pCI/l
Figure A-57. House OP-13 diagnostic measurements map
-------
TABLE A-39. HOUSE OP-13
INSTALLED MITIGATION TECHNIQUES
PHASE 1 - SEAL BLOCK TOPS AND BELOW-GRADE OPENINGS
AND PENETRATIONS. DEPRESSURIZE EXTERIOR
FOOTING DRAIN.
PHASE 2- DEPRESSURIZE SUB-SLAB. (DEACTIVATE EX-
TERIOR FOOTING DRAIN DEPRESSURIZATION
SYSTEM)
A-97
-------
>
00
O
Q.
z
QC
I-
z
HI
o
z
o
o
z
o
Q
z
HI
5
HI
m
PHASE 0 - PRE-MITIGATION
PHASE 1 - SEAL OPENINGS AND
DEPRESSURIZE EXTERIOR
FOOTING DRAIN
PHASE 2 - DEPRESSURIZE SUB-SLAB
PHASE 1 AVG. 2.9 pCI/l
PHASE 0 AVG. 13.9 pCI/l
o -
2/16/87
2/22/87
2/28/87
DATE (mm/dd/yy)
3/12/87
3/18/87
Figure A-58. House OP-13 radon concentrations: phase O, phase 1 and phase 2
-------
TABLE A-40. HOUSE OP-13
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION foCi/L)
MONITORING
PHASE DETECTOR* PERIOD
0
0
0
0
1
2
1**
1
. 1
1
1
1+
1
CC
GR
AT
CC
CR
CR
AT
AT
CC
AT
AT
AT
AT
08/25/86
11/13/86
12/11/86
02/16/87
02/26/87
03/10/87
09/19/87
02/09/88
03/08/88
03/08/88
03/13/88
06/21/88
11/29/88
- 08/29/86
- 01/07/87
- 02/19/87
- 03/09/87
- 03/17/87
- 02/09/88
- 03/13/88
- 03/13/88
- 06/14/88
- 06/21/88
- 11/29/88
- 03/07/89
BASEMENT
25
16
20
13.2,13
2
9
9.5
5.5,5
1
3
5.8
12'
1
.0
.3
.6
.8,14.0
.9
.1
,13.2
.7,6.1
.1
.1
,3.1
.8
.4
FIRST
FLOOR
—
11.5
12.7
9.7
-
-
7.0
5.7,8.
1.3
2.6
1.4,0.
4.0,3.
1.2,1.
2
9
2
1
* AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON,
GR = GRAB SAMPLE RADON
**EXTERIOR FOOTING DRAIN FAN BROKEN FOR PART OF TIME
-i- FAN SHUT OFF MOST OF THE TIME
A-99
-------
TABLE A-41. HOUSE OP-16
BUILDING CHARACTERISTICS
STYLE:
RAISED RANCH
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
WALL-WALL COMMUNICATION:
FLOOR OPENINGS:
WALL-SUB-SLAB COMMUNICATION:
SUB-SLAB AGGREGATE:
SUB-SLAB COMMUNICATION:
FOOTING DRAINS:
OPEN TOP BLOCK
MINOR CRACKS
MARGINAL
CRACKS, SUMP
GOOD
SOIL
MARGINAL
UNLIKELY
DIAGNOSTIC RADON MEASUREMENTS*
WELL WATER:
CC SCREENING:
GR SCREENING:
GR FOUNDATION WALLS:
GR SUB-SLAB:
35,000 PCI/L
33 PCI/L
53 PCI/L
574 PCI/L
46 PCI/L
*CC = CHARCOAL CANISTER, GR = GRAB SAMPLE RADON
GR = GRAB SAMPLE RADON
A-100
-------
>
__».
o
UJ
Q
z
O
CD
5
CO
GARAGE
BELOW-GRADE SLAB
BATHROOM
STAIRS
FAMILY ROOM
CLOSET UNDER STAIRS
SANITARY CLEAN-OUT PFT
O
I
O
m
SLAB-ON-GRADE
Figure A-59. House OP-16 lower level floor plan
-------
o
ro
LEGEND
SS1 - BENEATH FLOOR SLAB IN GARAGE
W1 - INTERIOR OF WALL IN GARAGE
W1-574pCI/l
SS1-46pCI/l
Figure A-60. House OP-16 diagnostic measurements map
-------
TABLE A-42. HOUSE OP-16
INSTALLED MITIGATION TECHNIQUES
PHASE 1 BLOCK TOPS AND BELOW-GRADE OPENINGS
AND PASSIVE VENT WALLS.
PHASE 2 - SEAL PASSIVE WALL VENTS AND ACTIVELY
DEPRESSURIZE WALLS.
A-103
-------
o
X
o
a
*«>
Z
g
h-
<
oc
f-
Z
111
O
z
o
o
z
o
a
<
DC
_J
UJ
>
UJ
_l
DC
UJ
o
80
70
60 -
50 -
40 -
30
20 -
10
PHASE 0 - PRE-MITIGATION
PHASE 1 - SEAL SUMP AND ACCESSIBLE BLOCK
TOPS AND PASSIVELY VENT WALLS
PHASE 0 AVG. 55.4 pCI/l
2/13/87
T
T
2/17/87
2/21/87 2/25/87
DATE (mm/dd/yy)
3/1/87
3/5/87
Figure A-61. House OP-16 radon concentrations: phase 0 and phase 1
-------
o
I/I
X
o
Q.
s_*»
O
cc
I-
z
111
o
z
o
o
z
o
Q
UJ
>
UJ
_l
cc
Ul
o
80
70 -
60 -
50 -
40
30
20 -
10 -
PHASE 2 - ACTIVELY DEPRESSURIZE WALLS
AND SEAL PASSIVE VENTS
PHASE 2 AVG. 22.7 pCI/l
0
3/17/87 3/18/87 3/19/87 3/20/87 3/21/87 3/22/87 3/23/87 3/24/87 3/25/87
DATE (mm/dd/yy)
Figure A-62. House OP-16 radon concentrations: phase 2
-------
o
O\
80
70
o 60
O
Z
O
oc
H
z
UJ
o
z
o
o
z
o
Q
<
DC
_J
UJ
>
UJ
_l
cc
UJ
o
50
40 H
30
20 H
10 -
0 -
PHASE 2 - ACTIVELY DEPRESSURIZE WALLS AND FOAM
CONCRETE BLOCKS
PHASE 2 AVG. 4.5 pCI/l (DURING FOAMING)
PHASE 2 AVG. 2.3 pCI/l (AFTER FOAMING)
7/15/87 7/17/87 7/19/87 7/21/87 7/23/87
7/16/87 7/18/87 7/20/87 7/22/87 7/24/87
DATE (mm/dd/yy)
Figure A-63. House OP-16 radon concentrations: phase 2 ( after foaming )
-------
TABLE A-43. HOUSE OP-16
INTEGRATED RADON CONCENTRATIONS
MONITORING
PHASE DETECTOR* PERIOD
0 CC
0 AT
0 GR
0 CC
0 CC
0 CR
1 CR
2 CR
2 CR
3 CR
10/01/86
12/11/86
02/13/87
02/13/87
02/13/87
02/13/87
02/20/87
03/17/87
06/12/87
07/18/87
- 10/05/86
- 01/08/87
- 02/16/87
- 02/16/87
- 02/18/87
- 03/04/87
- 03/24/87
- 07/01/87
- 07/23/87
RADON CONCENTRATION (r>Ci/L)
LOWER FIRST SECOND
LEVEL FLOOR FLOOR
32.7
25.6 7.6
52.8 56.4
66.7 42.1
71.2 45.9
55.4
40.1
22.7
10.0
2.3
* AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON,
GR = GRAB SAMPLE RADON
A-107
-------
TABLE A-44. HOUSE OP-17
BUILDING CHARACTERISTICS
STYLE:
BI-LEVEL
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
WALL-WALL COMMUNICATION:
FLOOR OPENINGS:
WALL-SUB-SLAB COMMUNICATION:
SUB-SLAB AGGREGATE:
SUB-SLAB COMMUNICATION:
FOOTING DRAINS:
OPEN TOP BLOCK
FINISHED BASEMENT
UNKNOWN
DRAINS, SUMP
MARGINAL
GRAVEL
GOOD
EXTERIOR LOOP
DIAGNOSTIC RADON MEASUREMENTS*
WELL WATER:
CC SCREENING:
GR SCREENING:
GR FOUNDATION WALLS:
GR SANITARY CLEAN-OUT PIT:
22,500 PCI/L
49 PCI/L
41 PCI/L
5 PCI/L
659 PCI/L
'CC = CHARCOAL CANISTER, GR = GRAB SAMPLE RADON
A-108
-------
o
CD
LU
Q
9
o
CO
=s
CO
WORKSHOP
FLOOR DRAIN
HOLLOW-CORE CONCRETE BLOCK WALLS
SLAB-ON-GRADE
BEDROOM
FURNACE ROOM
SANITARY CLEAN-OUT PIT
LAUNDRY
BATHROOM
STAIRS
BELOW-GRADE SLAB
Figure A-64, House OP-17 lower level floor plan
FAMILY ROOM
BEDROOM
00
m
O
5
o
m
en
5
CD
-------
LEGEND
SS1 - IN SANITARY PIT
W1 - INTERIOR OF EAST WALL
>
O
W1 - 5 pCi/l
SS1 - 659 pCi/l
Figure A-65. House OP-17 diagnostic measurements map
-------
TABLE A-45. HOUSE OP-17
INSTALLED MITIGATION TECHNIQUES
PHASE 1 - SEAL SLAB AND BLOCK OPENINGS. PROVIDE
PASSIVE SUB-SLAB DEPRESSURIZATION.
PHASE 2 - PROVIDE ACTIVE SUB-SLAB DEPRESSURIZATION.
A-lll
-------
DC
H
Z
LU
O
Z
O
O
z
O
D
CC
_J
UJ
UJ
DC
UJ
O
80
70
60 -
a
**—'
z
2 50
40 -
30
20
10
PHASE 0 - PRE-MITIGATION
PHASE 0 AVG. 37.1 pCI/l
T
T
T
1 1 1 1 1
2/13/87 2/15/87 . 2/17/87 2/19/87 2/21/87 2/23/87
2/14/87 2/16/87 2/18/87 2/20/87 2/22/87 2/24/87
DATE (mm/dd/yy)
Figure A-66. House OP-17 radon concentrations: phase 0
-------
80
70
- 60 -
O
a
z
O
H
2 50 -
cc
H
z
UJ
O
z
O
O
z
O
Q
cc
UJ
UJ
cc
UJ
O
40 -
30 -
20 -
10
0 -
PHASE 1 - SEAL SUMP AND PASSIVELY
DEPRESSURIZE SUB-SLAB
i—i—i—i—i—i—i—i—i—i—i—r
2/23/87
PHASE 1 AVG. 39.3pCI/l
i—i—|—r—i—I—i—i—'—I—i—i—i—i—i—I—i—i—i—i—i—i—i—i—i—r
2/24/87 2/25/87
DATE (mm/dd/yy)
Figure A-67. House OP-17 radon concentration: phase 1
-------
o
Q.
z
o
H-
<
cc
H
z
LU
O
Z
o
o
z
o
Q
<
CC
_l
UJ
>
UJ
oc
til
o
80
70 -
60
50 -
40 -
30
20
10
PHASE 2 - ACTIVELY DEPRESSURIZE SUB-SLAB
PHASE 2 AVG. 16.3 pCI/l
o -|
3/4/87 3/6/87 3/8/87 3/10/87 3/12/87
DATE (mm/dd/yy)
Figure A-68. House OP-17 radon concentration: phase 2
1 1 1 1
3/14/87 3/16/87 3/18/87
-------
-------
TABLE A-46. HOUSE OP-17
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION fpCi/L)
PHASE
0
0
0
0
0
1
2
3
3
3
3
3
3
3
3
3
MONITORING
DETECTOR* PERIOD
CC
CC
AT
CC
CR
CR
CR
CR
AT
AT
CC
CC
AT
AT
AT
AT
08/25/86
10/01/86
12/11/86
02/13/87
02/13/87
02/23/87
03/04/87
09/01/87
09/11/87
02/09/88
03/08/88
03/08/88
03/08/88
03/13/88
06/21/88
11/29/88
- 08/29/86
- 10/05/86
- 01/08/87
- 02/16/87
- 02/23/87
- 02/24/87
- 03/17/87
- 09/19/87
- 02/09/88
- 03/13/88
- 03/13/88
- 03/13/88
- 06/14/88
- 06/21/88
- 11/29/88
- 03/07/89
FIRST
BASEMENT FLOOR
14.0
49.2,49.4
23.7 12.2
41.5,42.2 20.5,22.4
37. 1
39.3
16.3
3.1
<0.2
5.5 4.2
8.6 5.3
4.9
2.7 5.9
6.6,8.0 4.2,5.3
4.1,4.2 2.9
8.2,7.8 5.0
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER, CR = CONTINUOUS RADON
A-116
-------
APPENDIX B
This appendix contains the specific details on assessing previously installed mitigation
techniques in existing houses as described in Section 3 of this report. The figures and tables
contained herein include the building characteristics, the mitigation techniques installed at each site
by phase, and tables summarizing all radon measurements taken at each site during this task. These
details provide support documentation on the results observed and conclusions reached for each site
as presented in Section 3.
B-l
-------
TABLE B-l. HOUSE NM-02
BUILDING CHARACTERISTICS
AGE AND STYLE:
WATER SUPPLY:
6 YR OLD BI-LEVEL
WELL (307 PCI/L)
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
TREATED WOOD
UNKNOWN (FINISHED)
TWO DRAINS
CRUSHED STONE
NONE
GARAGE, OPEN TO UPSTAIRS
CENTRAL HEATING:
FIREPLACES/STOVES:
VENTS AND OPENINGS:
AIR EXCHANGE PER
HOUR AT 50 PA:
HEAT PUMP FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
3.66
B-2
-------
TABLE B-2. HOUSE NM-02
INSTALLED MITIGATION TECHNIQUES
PHASE 1 VISIBLE FOUNDATION OPENINGS SEALED WITH
POLYURETHANE CAULK SUB-SLAB DEPRESSURIZED
WITH 20-WATT AXIAL FAN.
PHASE 2 - LEAKS IN SUB-SLAB DEPRESSURIZATION VENT SEALED
WITH POLYURETHANE CAULK. 20-WATT AXIAL FAN
REPLACED WITH 20-WATT CENTRIFUGAL FAN.
TABLE
INTEGRATED
B-3. HOUSE NM-02
RADON CONCENTRATIONS
RADON CONCENTRATION fDCi/L)
PHASE
1A
1A
IB
2A
2B
MONITORING
DETECTOR* PERIOD
AT
AT
AT
GR
CC
AT
CC
06/25/82
09/09/83
03/27/84
12/03/86
10/22/87
10/22/87
03/25/88
- 12/06/82
- 11/15/83
- 04/27/84
- 10/26/87
- 03/25/88
- 03/28/88
BASEMENT
4.8
9.0
3.5
7.7
1.9
1.4
2.3
FIRST
FLOOR
4.4
11.7
3.6
6.5
1.8
1.8
2.5
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER, GR = GRAB RADON
B-3
-------
TABLE B-4. HOUSE NM-05
BUILDING CHARACTERISTICS
AGE AND STYLE:
WATER SUPPLY:
7 YR OLD CONTEMPORARY
WELL (3 PCI/L)
FOUNDATION CHARACTERISTICS (BASEMENT AND CRAWL SPACES)
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
ACCESS TO CRAWL SPACES:
CRAWL SPACE FLOORS:
CRAWL SPACE VENTS:
CAPPED BLOCK
MINOR
SUMP, FLOOR/WALL OPENINGS
SAND
EXTERIOR AROUND TWO SIDES
GARAGE
BASEMENT/INACCESSIBLE
CONCRETE/SAND
NONE/VENT PIPE
CENTRAL HEATING:
FIREPLACES/STOVES:
VENTS AND OPENINGS:
AIR EXCHANGE PER
HOUR AT 50 PA:
HEAT PUMP FORCED-AIR
ONE WOOD STOVE
BATHROOM FANS
5.39
B-4
-------
TABLE B-5. HOUSE NM-05
INSTALLED MITIGATION TECHNIQUES
PHASE 1 - FLOOR-WALL CRACK SEALED WITH POLY-
URETHANE FOAM. SUMP COVERED WITH
PLYWOOD TOP, SEALED WITH BUTYL CAULK
AND DEPRESSURIZED WITH 20-WATT AXIAL
FAN. INACCESSIBLE CRAWL SPACE VENTED
WITH 20-WATT AXIAL FAN.
PHASE 2 - OPENINGS TO INACCESSIBLE CRAWL SPACE
SEALED WITH POLYURETHANE CAULK SUMP
DEPRESSURIZED, AND INACCESSIBLE CRAWL
SPACE VENTED, WITH 40-WATT CENTRIFUGAL
FAN. CRACKS RESEALED WITH POLYURETHANE
CAULK
TABLE
INTEGRATED
B-6. HOUSE NM-05
RADON CONCENTRATIONS
RADON CONCENTRATION
PHASE
1A
1A
IB
2A
2B
MONITORING
DETECTOR* PERIOD
AT
AT
AT
CC
AT
CC
AT
AT
AT
07/12/82
08/24/83
03/09/84
12/02/86
10/21/87
03/25/88
03/28/88
07/03/88
11/16/88
- 12/23/82
- 11/15/83
- 05/01/84
- 12/05/86
- 03/25/88
- 03/28/88
- 07/01/88
- 11/16/88
- 03/28/89
BASEMENT
16.6
16.2
3.0
23.0
5.4
4.6
2.6
2.7
2.7,3.0
FIRST
FLOOR
7.6
8.6
1.8
14.3
2.3
2.3
1.7
1.0
3.0
fDCi/L)
SECOND
FLOOR
5.3
8.4
1.6
-
2.2
2.0
1.2
1.3
2.8
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER
B-5
-------
TABLE B-7. HOUSE NM-12
BUILDING CHARACTERISTICS
AGE AND STYLE:
WATER SUPPLY:
5 YR OLD COLONIAL
PUBLIC (1 PCI/L)
FOUNDATION CHARACTERISTICS (BASEMENT AND CRAWL SPACE)
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
ACCESS TO CRAWL SPACE:
CRAWL SPACE FLOORS:
CRAWL SPACE VENTS:
POURED CONCRETE
MINOR
SUMP, FRENCH DRAIN, CRACKS
CRUSHED STONE
INTERIOR LOOP TO SUMP
UPSTAIRS
BASEMENT
CRUSHED STONE
NONE
CENTRAL HEATING:
FIREPLACES/STOVES:
VENTS AND OPENINGS:
AIR EXCHANGE PER
HOUR AT 50 PA:
GAS FORCED-AIR
ONE FIREPLACE
BATHROOM FANS
4.67
B-6
-------
TABLE B-8. HOUSE NM-12
INSTALLED MITIGATION TECHNIQUES
PHASE 1 - FRENCH DRAIN AND PENETRATIONS SEALED WITH
POLYURETHANE FOAM AND CAULK CRAWL SPACE
ISOLATED FROM BASEMENT (USING WEATHER-
STRIPPED PLYWOOD DOOR) AND VENTED TO OUT-
SIDE. SUMP SEALED WITH PLYWOOD TOP AND CAULK
AND DEPRESSURIZED USING 20-WATT AXIAL FAN.
PHASE 2 - FLOOR CRACK SEALED WITH NON-SHRINK GROUT.
AXIAL FAN REPLACED .WITH 20-WATT CENTRIFUGAL FAN.
TABLE B-9. HOUSE NM-12
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION foCi/L)
PHASE
1A
IB
2A
2B
MONITORING
DETECTOR* PERIOD
AT
AT
CC
CC
AT
AT
AT
AT
09/18/83
03/09/84
12/02/86
10/26/87
10/26/87
03/24/88
07/05/88
12/12/88
- 11/19/83
- 04/26/84
- 12/05/86
- 10/29/87
- 03/24/88
- 07/05/88
- 12/12/88
- 03/21/89
BASEMENT
18.3
2.9
4.7
4.9
1.8
3.7
2.6
1.8,2.0
FIRST SECOND
FLOOR FLOOR
5.4 12.9
0.8 1.4
2.4
1,4
0.9
2.2
1.3 0.7
1.3,1.9 2.0
*AT = APLPHA TRACK, CC = CHARCOAL CANISTER
B-7
-------
TABLE B-10. HOUSE NM-16
BUILDING CHARACTERISTICS
AGE AND STYLE:
WATER SUPPLY:
5 YR OLD CONTEMPORARY
PUBLIC (2 PCI/L)
SLAB-ON-GRADE CHARACTERISTICS
WALLS:
FLOOR OPENINGS:
AIR DUCTS IN SLAB:
SUB-SLAB AGGREGATE:
FOOTING DRAINS:
TREATED WOOD
LAUNDRY DRAIN
NONE
CRUSHED STONE
NONE
CENTRAL HEATING:
FIREPLACES/STOVES:
VENTS AND OPENINGS:
AIR EXCHANGE PER
HOUR AT 50 PA:
ELECTRIC RADIANT
NONE
BATHROOM FANS
4.95
B-8
-------
TABLE B-ll. HOUSE NM-16
INSTALLED MITIGATION TECHNIQUES
PHASE 1 - TIMER AND CONTROL INSTALLED ON EXISTING
HOME-MADE 70 CFM HEAT RECOVERY VENTILATOR.
TIMER SET TO ALLOW VENTILATOR TO RUN 15
MINUTES PER HOUR.
PHASE 2- NO MODIFICATIONS. FOLLOW-UP MONITORING
ONLY.
B-9
-------
TABLE B-12. HOUSE NM-16
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (pCi/L)
MONITORING
PHASE DETECTOR* PERIOD
0 AT
0 AT
1 AT
1 CC
1 AT
1 AT
1 AT
03/18/83
09/05/83
04/09/84
03/25/88
03/25/88
07/08/88
11/27/88
- 07/23/83
- 11/09/83
- 05/02/84
- 03/28/88
- 07/10/88
- 11/27/88
- 03/11/89
FIRST
FLOOR
0.5
2.4
2.4
2.3
1.5,2.0,2.1
1.7
2.5,2.5,2.8
SECOND
FLOOR
0.4
2.7
0.8
2.3
2.0,2.8
1.5
2.3
"AT = ALPHA TRACK, CC = CHARCOAL CANISTER
B-10
-------
TABLE B-13. HOUSE NM-19
BUILDING CHARACTERISTICS
AGE AND STYLE:
WATER SUPPLY:
VICTORIAN COLONIAL
PUBLIC (340 PCI/L)
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
ROCK AND MORTAR
SIGNIFICANT
SIGNIFICANT
NONE
NONE
OUTSIDE
CENTRAL HEATING:
FIREPLACES/STOVES:
VENTS AND OPENINGS:
AIR EXCHANGE PER
HOUR AT 50 PA:
GAS FORCED-AIR
NONE
NONE
. 12.31
B-ll
-------
TABLE B-14A. HOUSE NM-19
INSTALLED MITIGATION TECHNIQUES
PHASE 1 BASEMENT VENTED WITH 150 CFM HEAT
RECOVERY VENTILATOR SET TO RUN 10
MINUTES EVERY HOUR.
PHASE 2- NO MODIFICATIONS. FOLLOW-UP MONI-
TORING ONLY.
TABLE B-14B. HOUSE NM-19
INTEGRATED RADON CONCENTRATIONS
PHASE
1A
1A
IB
2A
2A
2A
2A
2A
MONITORING
DETECTOR* PERIOD
AT
AT
AT
CC
CC
AT
AT
AT
08/12/82
08/06/83
03/13/84
06/25/87
03/25/88
03/25/88
07/08/88
11/21/88
- 06/08/83
- 11/01/83
- 04/26/84
- 06/30/87
- 03/31/88
- 07/08/88
- 11/21/88
- 03/02/89
RADON CONCENTRATION
FIRST
BASEMENT FLOOR
17.7 2.5
19.9 1.6
12.1 2.5
0.5
19.3 3.8
12.5,16.9
12.0,10.4
9.7,10.3 2.8
foCi/L}
SECOND
FLOOR
—
1.4
3.0
-
3.7
2.0
-
2.4
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER
B-12
-------
TABLE B-15. HOUSE NM-21
BUILDING CHARACTERISTICS
AGE AND STYLE:
WATER SUPPLY:
6 YR OLD COLONIAL
PUBLIC (1 PCI/L)
BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
OPEN TOP BLOCKS
WEEPING HOLES
SUMP, FRENCH DRAIN
CRUSHED STONE
INTERIOR LOOP TO SUMP
OUTSIDE, UPSTAIRS
CENTRAL HEATING:
FIREPLACES/STOVES:
VENTS AND OPENINGS:
AIR EXCHANGE PER
HOUR AT 50 PA:
GAS FORCED-AIR
ONE FIREPLACE
JENNAIR, BATHROOM FANS
7.47
B-13
-------
TABLE B-16. HOUSE NM-21
INSTALLED MITIGATION TECHNIQUES
PHASE 1 FRENCH DRAIN SEALED WITH POLYURETHANE FOAM. TOP
OF CONCRETE BLOCKS SEALED WITH WOOD AND BUTYL
CAULK. INSIDE BASEMENT WALLS SEALED WITH CEMENT
PAINT. PORTIONS OF OUTSIDE BASEMENT WALLS SEALED
WITH CEMENT PARGETING. SUMP SEALED WITH PLYWOOD TOP
AND BUTYL CAULK AND VENTED WITH 30-WATT AXIAL FAN.
PHASE 2 AXIAL FAN REPLACED WITH NEW FAN (SAME MODEL).
LEAKS AROUND FAN AND VENT PIPE JOINTS SEALED WITH
POLYURETHANE CAULK. OUTSIDE VENT OPENING COVERED
WITH LOUVERED SCREEN.
TABLE B-17. HOUSE NM-21
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION
PHASE
1A
IB
2A
2B
2B
2B
2B
2B
MONITORING
DETECTOR* PERIOD
AT
AT
CC
AT
CC
AT
AT
AT
08/16/82
03/12/84
12/04/86
10/21/87
03/30/88
03/30/88
07/05/88
12/29/88
- 12/20/82
- 04/26/84
- 12/07/86
- 03/30/88
- 04/02/88
- 07/05/88
- 12/29/88
- 03/27/89
FIRST
BASEMENT FLOOR
49.
1.
2.
0.
1.
1.
0.
1.0,
8 15.0
4 0.9
9 1.5
2 0.2
0 0.7
0
6 0.2
1.3
(vCi/L]
SECOND
FLOOR
12.7
0.6
-
0.2
0.9
0.4
0.2
<0 . 3
AT - ALPHA TRACK. CC - CHARCOAL CANISTER
B-14
-------
TABLE B-18. HOUSE NM-26
BUILDING CHARACTERISTICS
AGE AND STYLE:
WATER SUPPLY:
7 YR OLD SALT BOX
WELL (30 PCI/L)
BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
POURED CONCRETE
DUCT AND PIPE PENETRATIONS
SUMP, FLOOR/WALL CRACK
NATURAL SOIL
SAND THERMAL STORAGE
UNKNOWN
UPSTAIRS
CENTRAL HEATING:
FIREPLACES/STOVES:
VENTS AND OPENINGS:
AIR EXCHANGE PER
HOUR AT 50 PA:
NONE
ONE WOOD STOVE
NONE
4.16
B-15
-------
TABLE B-19. HOUSE NM-26
INSTALLED MITIGATION TECHNIQUES
PHASE 1 FLOOR/WALL CRACKS AND OPENINGS AROUND
PIPE PENETRATIONS SEALED WITH POLY-
URETHANE CAULK. SUMP OPENING COVERED
WITH PLYWOOD AND SEALED. CIRCULATION
SYSTEM MODIFIED TO PROVIDE SLIGHT
POSITIVE PRESSURE.
PHASE 2 - NO MODIFICATIONS FOLLOW-UP MONITORING
ONLY.
B-16
-------
TABLE B-20. HOUSE NM-26
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION fpCi/L)
PHASE
1A
1A
IB
2A
2A
2A
2 A.
MONITORING
DETECTOR* PERIOD BASEMENT
AT
AT
AT
CC
AT
AT
AT
08/24/82
08/06/83
03/06/84
06/24/87
06/24/87
09/25/87
03/23/88
- 04/08/83 11.3
- 10/29/83 5.9
- 05/05/84 9.1
- 06/27/87
- 09/25/87
- 01/11/88
- 06/09/88
FIRST
FLOOR
8.6
6.7
4.1
1.2
1.5
9.3
6.2
SECOND
FLOOR
6.4
2.6
4.2
0.5
0.8
7.1
6.9
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER
B-17
-------
TABLE B-21A. HOUSE NM-28
BUILDING CHARACTERISTICS
AGE AND STYLE:
WATER SUPPLY:
1820 FARM HOUSE
WELL (115 PCI/L)
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
ROCK AND MORTAR
SIGNIFICANT
SIGNIFICANT
NONE
NONE
OUTSIDE, UPSTAIRS
CENTRAL HEATING:
FIREPLACES/STOVES:
VENTS AND OPENINGS:
AIR EXCHANGE PER
HOUR AT 50 PA:
PROPANE FORCED-AIR
ONE WOOD STOVE
BATHROOM FANS
6.84
B-18
-------
TABLE B-21B. HOUSE NM-28
INSTALLED MITIGATION TECHNIQUES
PHASE 1 BASEMENT VENTED WITH 150 CFM HEAT
RECOVERY VENTILATOR SET TO RUN CON-
TINUOUSLY.
PHASE 2 - NO MODIFICATIONS. FOLLOW-UP MONITORING
ONLY.
TABLE B-21C. HOUSE NM-28
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION foCi/L)
PHASE
1A
1A
IB
2A
2A
2A
2A
2A
MONITORING
DETECTOR* PERIOD BASEMENT
AT
AT
AT
CC
AT
AT
AT
AT
08/25/82
09/11/83
03/29/84
06/30/87
06/30/87
09/24/87
01/05/88
03/21/88
- 04/09/83
- 11/01/83
- 04/30/84
- 07/03/87
- 09/24/87
- 01/05/88
- 03/21/88
- 06/07/88
9.3
-
4.8
3.6
2.5
5.1
6.5
4.8
FIRST
FLOOR
5.9
1.9
1.4
1.6
0.8
2.8
4-. 3
2.7
SECOND
FLOOR
3.6
-
1.5
1.5
1.1
5.1
7.7
"
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER
B-19
-------
TABLE B-22. HOUSE NM-29
BUILDING CHARACTERISTICS
AGE AND STYLE:
WATER SUPPLY:
6 YR OLD BI-LEVEL
PUBLIC (14 PCI/L)
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
POURED CONCRETE
NONE
DUCTS FROM THERMAL STORAGE
SAND THERMAL STORAGE
UNKNOWN
UPSTAIRS
CENTRAL HEATING:
FIREPLACES/STOVES:
VENTS AND OPENINGS:
AIR EXCHANGE PER
HOUR AT 50 PA:
ELECTRIC BASEBOARD
ONE WOOD STOVE
NONE
2.42
B-20
-------
TABLE B-23. HOUSE NM-29
INSTALLED MITIGATION TECHNIQUES
PHASE 1 - WHOLE HOUSE VENTED WITH 150 CFM
HEAT RECOVERY VENTILATOR SET TO
RUN 15 MINUTES EVERY HOUR.
PHASE 2- NO MODIFICATIONS. FOLLOW-UP MONI-
TORING ONLY.
TABLE B-24. HOUSE NM-29
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION fcCi/L)
MONITORING
PHASE
1A
1A
IB
2A
2A
2A
2A
2A
DETECTOR* PERIOD BASEMENT
AT
AT
AT
CC
AT
AT
AT
AT
08/26/82
08/07/83
03/07/84
07/08/87
07/08/87
09/24/87
01/04/88
03/21/88
- 04/19/83
- 10/29/83
- 04/30/84
- 07/12/87
- 09/24/87
- 01/04/88
- 03/21/88
- 06/07/88
7.4
0.8
2.3
0.8
0.2
7.4
12.5
2.6
FIRST
FLOOR
7.6
1.3
3.7
0.8
0.5
6.7
11.1
2.6
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER
B-21
-------
TABLE B-25. HOUSE NM-31
BUILDING CHARACTERISTICS
AGE AND STYLE:
WATER SUPPLY:
21 YR OLD BI-LEVEL
PUBLIC (2 PCI/L)
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
BLOCK
UNKNOWN (FINISHED)
DRAIN, FLOOR/WALL CRACKS
CRUSHED STONE
UNKNOWN
OUTSIDE, OPEN TO UPSTAIRS
CENTRAL HEATING:
FIREPLACES/STOVES:
VENTS AND OPENINGS:
AIR EXCHANGE PER
HOUR AT 50 PA:
GAS FORCED-AIR
ONE COAL STOVE INSERT
ONE FIREPLACE
BATHROOM FANS
2.63
B-22
-------
TABLE B-26. HOUSE NM-31
INSTALLED MITIGATION TECHNIQUES
PHASE 1 SUB-SLAB DEPRESSURIZED IN TWO
LOCATIONS WITH TWO 20-WATT AXIAL
FANS.
PHASE 2 LEAKS IN SUB-SLAB DEPRESSURIZA-
TION VENT SEALED WITH POLYURETHANE
CAULK. 20-WATT AXIAL FANS REPLACED
WITH 20-WATT CENTRIFUGAL FANS.
B-23
-------
TABLE B-27. HOUSE NM-31
INTEGRATED RADON CONCENTRATIONS
PHASE
1A
1A
2A
2B
2B
RADON CONCENTRATION fpCi/L)
MONITORING FIRST
DETECTOR* PERIOD BASEMENT FLOOR
AT 10/07/83
AT 03/26/84
CC 03/30/88
AT 03/30/88
AT 07/07/88
- 11/26/83 - 15.5
- 04/26/84 2.0 1.3
- 04/02/88 0.9 1.3
- 07/07/88 1.1 0.4,0.7
- 12/12/88 - 1.4
AT = ALPHA TRACK, CC = CHARCOAL CANISTER
B-24
-------
TABLE B-28. HOUSE NM-37
BUILDING CHARACTERISTICS
AGE AND STYLE:
WATER SUPPLY:
7 YR OLD COLONIAL
PUBLIC (1 PCI/L)
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
POURED CONCRETE
MINOR
SUMP, FRENCH DRAIN
CRUSHED STONE
INTERIOR LOOP TO SUMP
UPSTAIRS
CENTRAL HEATING:
FIREPLACES/STOVES:
VENTS AND OPENINGS:
AIR EXCHANGE PER
HOUR AT 50 PA:
ELECTRIC BASEBOARD
NONE
BATHROOM FANS
10.85
B-25
-------
TABLE B-29. HOUSE NM-37
INSTALLED MITIGATION TECHNIQUES
PHASE 1
FRENCH DRAIN SEALED WITH POLYURETHANE FOAM
AND CAULK. FLOOR CRACK SEALED WITH NON-
SHRINK GROUT. SUMP SEALED AND VENTED TO
OUTSIDE WITH 20-WATT AXIAL FAN.
PHASE 2
AXIAL FAN REPLACED WITH 20-WATT CENTRIFUGAL
FAN. OUTSIDE LOWERED SHUTTER REPLACED WITH
SCREENED RAIN CAP. JOINTS AND PENETRATIONS
RESEALED.
TABLE B-30. HOUSE NM-37
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION
PHASE
1A
1A
IB
2A
2B
2B
2B
2B
2B
2B
MONITORING
DETECTOR* PERIOD
AT
AT
AT
CC
CC
AT
CC
AT
AT
AT
09/10/82
08/17/83
03/01/84
09/26/87
11/17/87
11/17/87
03/25/88
03/25/88
06/30/88
12/16/88
- 06/10/83
- 11/16/83
- 04/27/84
- 09/29/87
- 11/21/87
- 03/25/88
- 03/28/88
- 06/30/88
- 12/16/88
- 04/06/89
BASEMENT
31.5
28.3
8.1
11.3
6.2
2.7
8.8
-
3.6
—
FIRST
FLOOR
-
4.8
2.9
4.1
2.5
1.5
2.5
1.6
0.7
2.2
fpci/D
SECOND
FLOOR
-
4.9
3.6
3.1
1.8
1.0
-
1.3
1.6
1.8
AT = ALPHA TRACK, CC = CHARCOAL CANISTER
B-26
-------
TABLE B-31. HOUSE NM-41
BUILDING CHARACTERISTICS
AGE AND STYLE:
WATER SUPPLY:
8 YR OLD COLONIAL
PUBLIC (10 PCI/L)
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
ACCESS TO CRAWL SPACE:
CRAWLSPACE FLOOR:
CRAWLSPACE VENTS:
POURED CONCRETE
MINOR
UNPAVED AREA, SUMP
SANDY SOIL
NONE
UPSTAIRS
BASEMENT
SANDY SOIL
PASSIVE VENTS
CENTRAL HEATING:
FIREPLACES/STOVES:
VENTS AND OPENINGS:
AIR EXCHANGE PER
HOUR AT 50 PA:
ELECTRIC BASEBOARD
ONE WOOD STOVE
NONE
3.83
B-27
-------
TABLE B-32. HOUSE NM-41
INSTALLED MITIGATION TECHNIQUES
PHASE 1 UNPAVED FLOOR AREAS FILLED WITH
CONCRETE AND FLOOR WALL JOINT SEALED
WITH POLYURETHANE CAULK. THERMAL BY-
PASS FROM BASEMENT TO SECOND FLOOR
SEALED.
PHASE 2 NO MODIFICATIONS. FOLLOW-UP MONITORING
ONLY.
B-28
-------
TABLE B-33. HOUSE NM-41
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION fuCi/L)
PHASE
1A
1A
IB
2A
2A
2A
2A
MONITORING
DETECTOR* PERIOD
AT
AT
AT
CC
AT
AT
AT
09/20/82 -
08/05/83 -
03/02/84 -
12/03/86 -
04/01/88 -
07/07/88 -
12/09/88 -
04/29/83
10/29/83
04/03/84
12/06/86
07/11/88
12/09/88
03/16/89
BASEMENT
4.8
-
2.6
2.6
4.3
2.8
2.7,3.5
FIRST SECOND
FLOOR FLOOR
2.0 3.7
0.9 0.3
1.6 1.0
3.3
1.7
1.7 1.5
1.9
AT = ALPHA TRACK, CC = CHARCOAL CANISTER
B-29
-------
TABLE B-34. HOUSE NM-51
BUILDING CHARACTERISTICS
AGE AND STYLE:
WATER SUPPLY:
6 YR OLD ONE-LEVEL UNDERGROUND
WELL (206 PCI/L)
FULL BASEMENT CHARACTERISTICS
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
POURED CONCRETE
NONE
DRAIN
SANDY SOIL
NONE
GARAGE, OUTSIDE
CENTRAL HEATING:
FIREPLACES/STOVES:
VENTS AND OPENINGS:
AIR EXCHANGE PER
HOUR AT 50 PA:
ELECTRIC BASEBOARD
ONE WOOD STOVE
HEAT RECOVERY VENTILATOR
0.93
B-30
-------
TABLE B-35. HOUSE NM-51
INSTALLED MITIGATION TECHNIQUES
PHASE 1 DRAIN SEALED AND EXISTING HEAT
RECOVERY VENTILATOR ACTIVATED
WITH HUMIDISTAT CONTROL.
PHASE 2- NO MODIFICATIONS. FOLLOW-UP MONI-
TORING ONLY.
B-31
-------
TABLE B-36. HOUSE NM-51
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION fpCi/Ll
MONITORING
PHASE DETECTOR* PERIOD BASEMENT
1A
1A
IB
2A
2 A
2 A
2A
2 A
2A
AT
AT
AT
CC
AT
AT
AT
AT
AT
10/01/82 -
08/18/83 -
03/29/84 -
06/24/87 -
06/24/87 -
06/24/87 -
09/24/87 -
01/05/88 -
03/23/88 -
01/18/83
11/04/83
05/02/84
06/27/87
09/24/87
06/09/88
01/05/88
03/03/88
06/09/88
1.9
0.8
1.0
1.4
0.9
1.9
1.9
2.1
2.0,2.1
AT = ALPHA TRACK, CC = CHARCOAL CANISTER
B-32
-------
TABLE B-37. HOUSE NM-56
BUILDING CHARACTERISTICS
AGE AND STYLE:
WATER SUPPLY:
7 YR OLD COLONIAL
WELL (828 PCI/L)
FOUNDATION CHARACTERISTICS (BASEMENT AND CRAWL SPACE)
WALLS:
WALL OPENINGS:
FLOOR OPENINGS:
SUB-SLAB AGGREGATE:
FOOTING DRAINS:
ACCESS TO BASEMENT:
ACCESS TO CRAWL SPACE:
CRAWLSPACE FLOOR:
CRAWLSPACE VENTS:
BLOCK
PIPE PENETRATIONS
FLOOR/WALL CRACKS
UNKNOWN IN BASEMENT
SAND STORAGE IN CRAWL SPACE
UNKNOWN
UPSTAIRS
BASEMENT
CONCRETE
NONE
CENTRAL HEATING:
FIREPLACES/STOVES:
VENTS AND OPENINGS:
AIR EXCHANGE PER
HOUR AT 50 PA:
OIL FORCED-AIR
ONE FIREPLACE
NONE
6.49
B-33
-------
TABLE B-38. HOUSE NM-56
INSTALLED MITIGATION TECHNIQUES
PHASE 1 PIPE PENETRATIONS AND CRACKS SEALED
WITH POLYURETHANE CAULK. CRAWL SPACE
ISOLATED FROM BASEMENT WITH WEATHER-
STRIPPED PLYWOOD DOOR. BASEMENT VENTED
TO OUTSIDE WITH SITE-BUILT HEAT RECOVERY
VENTILATOR.
PHASE 2 - NO MODIFICATIONS. FOLLOW-UP MONITORING
ONLY.
B-34
-------
TABLE B-39. HOUSE NM-56
INTEGRATED RADON CONCENTRATIONS
RADON CONCENTRATION (DCi/L)
PHASE
1A
1A
IB
2A
2A
2A
2A
2A
MONITORING
DETECTOR* PERIOD
AT
AT
AT
CC
AT
AT
AT
AT
10/25/82
08/22/83
03/20/84
06/29/87
06/25/87
09/24/87
01/08/88
03/23/88
- 01/26/83
- 11/22/83
- 05/03/84
- 07/02/87
- 09/24/87
- 01/08/88
- 03/23/88
- 06/07/88
FIRST
BASEMENT FLOOR
2
4
1
1
1
1
2
1
.5
.0
.9
.8
.1
.9
.4
.8
1.
0.
0.
1.
0.
1.
1.
1.
7
9
9
3
8
5
5
2
SECOND
FLOOR
1.
1.
-
2.
0.
1.
1.
0.
2
0
4
6
7
3
8
*AT = ALPHA TRACK, CC = CHARCOAL CANISTER
B-35
------- |