950R91035
United Slates Air and Energy Environmental
Environmental Protection Research Laboratory April 1991
Agency Research Triangle Park NC 27711
Research and Development
k>EPA The 1991 International
Symposium on Radon
and Radon Reduction
Technology:
Volume 4. Preprints
Session VII: State Programs and
Policies Relating to Radon
Session VIII: Radon Prevention
in New Construction
April 2-5,1991
Adam's Mark Hotel
Philadelphia, Pennsylvania
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The 1991 International
Symposium on Radon and
Radon Reduction Technology
"A New Decade of Progress"
April 2-5,1991
Adam's Mark Hotel
Philadelphia, Pennsylvania
Sponsored by:
U.S. Environmental Protection Agency
Air and Energy Engineering Research Laboratory
and
U. S. Environmental Protection Agency
Office of Radiation Programs
and
Conference of Radiation Control Program Directors, Inc.
(CRCPD)
Printed on Recycled Paper
U.S. EPA Region III
Regional Center for Environmental
Information
1650 Arch Street (3PM52)
Philadelphia, PA 19103
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The 1991 International Symposium on Radon
and Radon Reduction Technology
Opening Session
Opening Remarks Symposium Co-Chairpersons
Introduction Charles M. Hardin, CRCPD, Inc.
Welcome Edwin B. Erickson,
EPA Region III Administrator
An Overview of the NAS Report on Radon Dosimetry Jonathan Samet
New Mexico Tumor Registry
iii
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The 1991 International Symposium on Radon
and Radon Reduction Technology
Table of Contents
Session I: Government Programs and Policies Relating to Radon
The Need for Coordinated International Assessment of the
Radon Problem - the IAEA Approach
Friedrich Steinhausler, International Atomic Energy Agency, Austria 1-1
The European Research Program and the Commission of
European Communities
Jaak Sinnaeve, Belgium I-2
United Kingdom Programs
Michael O'Riordan, National Radiological Protection Board, UK |-3
The U.S. DOE Radon Research Program: A Different Viewpoint
Susan L. Rose, Office of Energy Research, U. S. DOE I-4
U.S. EPA Future Directions
Margo Oge, U.S. EPA, Office of Radiation Programs I-5
Session I Posters
The State Indoor Radon Grants Program: Analysis of Results
After the First Year of Funding
Sharon Saile, U.S. EPA, Office of Radiation Programs IP-1
EPA Radon Policy and Its Effects on the Private Sector
David Saum and Marc Messing, INFILTEC IP-2
Evaluation of EPA's National Radon Contractor Proficiency Program
and Network of Regional Radon Training Centers
G. Lee Salmon, U.S. EPA, Office of Radiation Programs IP-3
State Certification Guidance
John Hoornbeek, U.S. EPA, Office of Radiation Programs IP-4
The U.S. EPA Radon Measurement Proficiency (RMP) Program
Jed Harrison, U.S. EPA, Office of Radiation Programs IP-5
iv
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Session II: Radon-Related Health Studies
Residential Radon Exposure and Lung Cancer in Women
Goran Pershagen, Karolinska Institute, Sweden 11-1
An Evaluation of Ecologic Studies of Indoor Radon and Lung Cancer
Christine Stidley, University of New Mexico II-2
Comparison of Radon Risk Estimates
Richard Hornung, NIOSH II-3
Lung Cancer in Rats Exposed to Radon/Radon Progeny
F. T. Cross and G. E. Dagle, Pacific Northwest Laboratory II-4
Startling Radon Risk Comparisons
JoAnne D. Martin, DMA-RADTECH, Inc II-5
Estimated Levels of Radon from Absorbed Polonium-210 in Glass
Hans Vanmarcke, Belgium II-6
Expanded and Upgraded Tests of the Linear-No Threshold Theory
for Radon-Induced Lung Cancer
Bernard L. Cohen, University of Pittsburgh li-7
Session II Panel: Risk Communication
Apathy vs. Hysteria, Science vs. Drama: What Works in Radon
Risk Communication
Peter Sandman, Rutgers University II-8
American Lung Association's Radon Public Information Program
Leyla Erk McCurdy, American Lung Association li-9
Ad Council Radon Campaign Evaluation
Mark Dickson and Dennis Wagner, U.S. EPA, Office of
Radiation Programs N-10
Developing a Community Radon Outreach Program: A Model for
Statewide Implementation
M. Jeana Phelps, Kentucky Cabinet for Human Resources 11-11
v
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Session II Posters
Occupational Safety During Radon Mitigation: Field Experience and
Survey Monitoring Results
Jean-Claude F. Dehmel, S. Cohen & Associates; Peter Nowlan,
R. F. Simon Company; Eugene Fisher, U.S. EPA,
Office of Radiation Programs IIP-1
Consumer Cost/Benefit Analysis of Radon Reductions in 146 Homes
Kenneth D. Wiggers, American Radon Services, Ltd IIP-2
The Effect of Passive Cigarette Smoke on Working Level
Exposures in Homes
Raymond H. Johnson, Jr. and Randolph S. Kline, Key Technology, Inc.;
Eric Geiger and Augustine Rosario, Jr., Radon QC IIP-3
Session III: Measurement Methods
Quality Assurance of Radon and Radon Decay Product Measurements
During Controlled Exposures
Douglas J. Van Cleef, U.S. EPA, Office of Radiation Programs 111-1
Current Status of Glass as a Retrospective Radon Monitor
Richard Lively, MN Geological Survey, and Daniel Steck,
St. John's University III-2
Soil Gas Measurement Technologies
Harry E. Rector, GEOMET Technologies, Inc IM-3
Results From a Pilot Study to Compare Residential Radon Concentrations
with Occupant Exposures Using Personal Monitoring
B. R. Litt, New Jersey Department of Environmental Protection,
J. M. Waldman, UMDNJ, and N. H. Harley and P. Chittaporn,
New York University Medical Center III-4
Rapid Determination of the Radon Profile in a Structure by
Measuring Ions in the Ambient Atmosphere
W. G. Buckman and H. B. Steen III, Western Kentucky University III-5
Intercomparison of Activity Size Distribution Measurements with
Manual and Automated Diffusion Batteries - Field Test
P. K. Hopke and P. Wasiolek, Clarkson University; E. 0. Knutson,
K. W. Tu, and C. Gogolak, U. S. DOE; A. Cavallo and K. Gadsby,
Princeton University; D. Van Cleef, NAREL III-6
vi
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Influence of Radon Concentrations on the Relationship Among Radon
Measurements Within Dwellings
Judith B. Klotz, NJ State Department of Health 111-7
The Use of Indoor Radon Measurements and Geological Data in Assessing
the Radon Risk of Soil and Rock in Construction Sites in Tampere
Anne Voutilainen and llona Makelainen, Finnish Centre for
Radiation and Nuclear Safety 111-8
Session III Panel: Detection of Radon Measurement Tampering
Policy and Technical Considerations for the Development of EPA
Guidance on Radon and Real Estate
Lawrence Pratt, U. S. EPA, Office of Radiation Programs 111-9
State Property Transfer Laws Now Include Radon Gas Disclosure
Michael A. Nardi, The Nardi Group 111-10
Update of AARST Real Estate Testing Guidelines
William P. Brodhead, WPB Enterprises 111-11
Real Estate Transaction Radon Testing Interference
Dean Ritter, ABE Testing 111-12
How to Determine if Radon Measurement Firms are Providing
Accurate Readings
Herbert C. Roy and Mohammed Rahman, New Jersey Department
of Environmental Protection 111-13
Grab Sampling as a Method of Discovering Test Interference
Marvin Goldstein, Building Inspection Service, Inc 111-14
Exploring Software Device Management Routines that Ensure the Overall
Quality of Continuous Working Level and Continuous Radon Monitor
Performance in a Field Environment
Richard Tucker, Gemini Research, and Rick Holland,
Radonics, Inc 111-15
Use of Grab Samples as a Quality Assurance Tool to Enhance Overall
Radon Measurement Accuracy and Reproducibility
Brian Fimian, Radonics, Inc., and Richard Tucker, Gemini Research 111-16
vii
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Session III Panel: Short-Term/Long-Term Measurement
Predicting Long-Term Indoor Radon Concentrations from Short-Term
Measurements: Evaluation of a Method Involving Temperature Correction
T. Agami Reddy, A. Cavallo, K. Gadsby, and R. Socolow,
Princeton University 111-17
Correlation Between Short-Term and Long-Term Indoor Radon
Concentrations in Florida Houses
Susan E. McDonough, Southern Research Institute 111-18
Relationship Between Two-day Screening Measurements of Radon-222
and Annual Living Area Averages in Basement and
Nonbasement Houses
S. B. White, N. F. Rodman, and B. V. Alexamder, Research Triangle
Institute; J. Phillips and F. Marcinowski, U. S. EPA, Office of
Radiation Programs 111-19
The Use of Multiple Short-Term Measurements to Predict Annual Average
Radon Concentrations
Frank Marcinowski, U. S. EPA, Office of Radiation Programs III-20
Session III Posters
Characterization of Structures Using Simultaneous Single Source
Continuous Working Level and Continuous Radon Gas Measurements
Brian Fimian and John E. McGreevy, Radonics, Inc IIIP-1
Pennsylvania Department of Environmental Resources Radon in Water
Measurement Intercomparison
Douglas Heim and Carl Granlund, Pennsylvania Department of
Environmental Resources IIIP-2
A Field Comparison of Several Types of Radon Measurement Devices
Elhannan L. Keller, Trenton State College IIIP-3
Radon and Water Vapor Co-Adsorption on Solid Adsorbents
Neguib M. Hassan, Tushar K. Ghosh, Sudarshan K. Loyalka,
and Anthony L. Hines, University of Missouri-Columbia, and
Davor Novosel, Gas Research Institute IIIP-4
Calibration of Modified Electret Ion Chamber for Passive Measurement
of Radon-222 (Thoron) in Air
P. Kotrappa and J. C. Dempsey, Rad Elec, Inc IIIP-5
viii
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Unit Ventilator Operation and Radon Concentrations in a
Pennsylvania School
William P. Brodhead, WPB Enterprises .IIIP-6
Session IV: Radon Reduction Methods
Causes of Elevated Post-Mitigation Radon Concentrations in Basement
Houses Having Extremely High Pre-Mitigation Levels
D. Bruce Henschel, AEERL; Arthur G. Scott, AMERICAN
ATCON, Inc IV-1
A Measurement and Visual Inspection Critique to Evaluate the
Quality of Sub-Slab Ventilation Systems
Richard W. Tucker, Gemini Research, Inc.; Keith S. Fimian,
Radonics, Inc IV-2
Correlation of Diagnostic Data to Mitigation System Design and
Performance as Related to Soil Pressure Manipulation
Ronald F. Simon, R. F. Simon Company IV-3
Pressure Field Extension Using a Pressure Washer
William P. Brodhead, WPB Enterprises IV-4
A Variable and Discontinuous Subslab Ventilation System and Its
Impact on Radon Mitigation
Willy V. Abeele, New Mexico Environmental Improvement Division IV-5
Natural Basement Ventilation as a Radon Mitigation Technique
A. Cavallo, K. Gadsby, and T.A. Reddy, Princeton University IV-6
Attic Pressurization - A Radon Mitigation Technique for Residential Structures
Myron R. Edelkind, Southern Mechanical IV-7
Section IV Posters
Radon Mitigation Failure Modes
William M. Yeager, Research Triangle Institute; D. Bruce Harris, AEERL;
Terry Brennan and Mike Clarkin, Camroden Associates, Inc IVP-1
Mitigation by Sub-SlabDepressurization Under Structures Founded on
Relatively Impermeable Sand
Donald A. Crawshaw and Geoffrey K. Crawshaw, Pelican
Environmental Corporation IVP-2
ix
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A Laboratory Test of the Effects of Various Rain Caps on Sub-Slab
Depressurization Systems
Mike Clarkin, Camroden Associates, Inc IVP-3
Analysis of the Performance of a Radon Mitigation System Based on
Charcoal Beds
P. Wasiolek, N. Montassier, P. K. Hopke, Clarkson University;
R. Abrams, RAd Systems, Inc IVP-4
Control of Radon Releases in Indoor Commercial Water Treatment
D. Bruce Harris and A. B. Craig, AEERL IVP-5
Session V: Radon Entry Dynamics
A Modeling Examination of Parameters Affecting Radon and Soil Gas
Entry Into Florida-Style Slab-on-Grade Houses
G. G. Sextro, Lawrence Berkeley Laboratory V-1
Effect of Winds in Reducing Sub-Slab Radon Concentrations Under
Houses Laid Over Gravel Beds
P. C. Owczarski, D. J. Holford, K. W. Burk, H. D. Freeman, and
G. W. Gee, Pacific Northwest Laboratory V-2
Radon Entry Into Dwellings Through Concrete Floors
K. K. Nielson and V. C. Rogers, Rogers and Associates
Engineering Corporation V-3
Radon Dynamics in Swedish Dwellings: A Status Report
Lynn M. Hubbard, National Institute of Radiation Protection, Sweden V-4
Soil Gas and Radon Entry Potentials for Slab-on-Grade Houses
Bradley H. Turk, New Mexico; David Grumm, Yanxia Li, and Stephen
D. Schery, New Mexico Institute of Mining and Technology;
D. Bruce Henschel, AEERL V-5
Direct Measurement of the Dependence of Radon Flux Through
Structure Boundaries on Differential Pressure
D. T. Kendrick and G. Harold Langner, Jr., U.S. DOE/Chem-Nuclear
Geotech, Inc V-6
Radon Resistance Under Pressure
William F. McKelvey, Versar, Inc.; Jay W. Davis, Versar A/E, Inc V-7
Recommendations to Reduce Soil Gas Radon Entry Based on an
Evaluation of Air Permeability of Concrete Blocks and Coatings
J. S. Ruppersberger, U. S. EPA, Office of Research and Development V-8
X
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Session V Posters
A Simple Model for Describing Radon Migration and Entry Into Houses
Ronald B. Mosley, AEERL VP-1
Effect of Non-Oarcy Flow on the Operation of Sub-Slab
Depressurization Systems
R. G. Sextro, Lawrence Berkeley Laboratory VP-2
Effects of Humidity and Rainfall on Radon Levels in a Residential Dwelling
Albert Montague and William E. Belanger, U. S. EPA;
Francis J. Haughey, Rutgers University VP-3
Session VI: Radon Surveys
Factors Associated with Home Radon Concentrations in Illinois
Thomas J. Bierma and Jennifer O'Neill, Illinois State University VI-1
Radon in Federal Buildings
Michael Boyd, U. S. EPA, Office of Radiation Programs VI-2
Radon in Switzerland
H. Surbeck and H. Volkle, University Perolles; W. Zeller, Federal
Office of Public Health VI-3
A Cross-Sectional Survey of Indoor Radon Concentrations in 966 Housing
Units at the Canadian Forces Base in Winnipeg, Manitoba
D. A. Figley and J. T. Makohon, Saskatchewan Research Council VI-4
Radon Studies in British Columbia, Canada
D. R. Morley and B. G. Phillips, Ministry of Health; M. M. Ghomshei,
Orchard Geothermal Inc.; C. Van Netten, The University of
British Columbia VI-5
The State of Maine Schools Radon Project: Results
L. Grodzins, NITON Corporation; T. Bradstreet, Division of Safety
and Environmental Services, Maine; E. Moreau, Department of
Human Services, Maine VI-6
Radon in Belgium: The Actual Situation and Plans for the Future
A. Poffijn, State University of Gent VI-7
A Radiological Study of the Greek Radon Spas
P. Kritidis, Institute of Nuclear Technology - Radiation Protection VI-8
xi
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Session VI Posters
A Cumulative Examination of the State/EPA Radon Survey
Jeffrey Phillips, U. S. EPA, Office of Radiation Programs VIP-1
Seasonal Variation in Two-Day Screening Measurements of Radon-222
Nat F. Rodman, Barbara V. Alexander, and S. B. White, Research
Triangle Institute; Jeffrey Phillips and Frank Marcinowski,
U. S. EPA, Office of Radiations Programs VIP-2
The State of Maine School Radon Project: Protocols and Procedures of
the Testing Program
Lee Grodzins and Ethel G. Romm, NITON Corporation;
Henry E. Warren, Bureau of Public Improvement, Maine viP-3
Results of the Nationwide Screening for Radon in DOE Buildings
Mark D. Pearson, D. T. Kendrick, and G. H. Langner, Jr., U. S. DOE/
Chem-Nuclear Geotech, Inc VIP-4
Session VII: State Programs and Policies Relating to Radon
Washington State's Innovative Grant: Community Support Radon Action
Team for Schools
Patricia A. McLachlan, Department of Health, Washington VII-1
Kentucky Innovative Grant: Radon in Schools Telecommunication Project
M. Jeana Phelps, Kentucky Cabinet for Human Resources;
Carolyn Rude-Parkins, University of Louisville VII-2
Regulation of Radon Professionals by States: the Connecticut Experience
and Policy Issues
Alan J. Siniscalchi, Zygmunt F. Dembek, Nicholas Maceiletti, Laurie
Gokey, and Paul Schur, Connecticut Department of Health Services;
Susan Nichols, Connecticut Department of Consumer Protection;
Jessie Stratton, State Representative, Connecticut
General Assembly VII-3
New Jersey's Program - A Three-tiered Approach to Radon
Jill A. Lapoti, New Jersey Department of Environmental Protection VIM
Session VII Posters
Quality Assurance - The Key to Successful Radon Programs in the 1990s
Raymond H. Johnson, Jr., Key Technology, Inc VIIP-1
xii
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Radon in Illinois: A Status Report
Richard Allen and Melanie Hamel-Caspary, Illinois Department
of Nuclear Safety VIIP-2
Session VIII: Radon Prevention in New Construction
Long-Term Monitoring of the Effect of Soil and Construction Type on
Radon Mitigation Systems in New Houses
D. B. Harris, U. S. EPA, Office of Research and Development VIII-1
A Comparison of Indoor Radon Concentrations Between Preconstruction
and Post-Construction Mitigated Single Family Dwellings
James F. Burkhart, University of Colorado at Colorado Springs;
Douglas L. Kladder, Residential Service Network, Inc VIII-2
Radon Reduction in New Construction: Double-Barrier Approach
C. Kunz, New York State Department of Health VIII-3
Radon Control - Towards a Systems Approach
R. M. Nuess and R. J. Prill, Washington State Energy Office VIII -4
Mini Fan for SSD Radon Mitigation
David Saum, INFILTEC VIII-5
Building Radon Mitigation into Inaccessible Crawlspace New
Residential Construction
D. Bruce Harris and A. B. Craig, AEERL; Jerry Haynes, Hunt
Building Corporation VIII-6
The Effect of Subslab Aggregate Size on Pressure Held Extension
K. J. Gadsby, T. Agami Reddy, D. F. Anderson, and R. Gafgen,
Princeton University; A. B. Craig, AEERL VIII-7
Session VIII Posters
Radon Prevention in Residential New Construction: Passive Designs
That Work
C. Martin Grisham, National Radon Consulting Group VIIIP-1
Preliminary Results of HVAC System Modifications to Control Indoor
Radon Concentrations
Terry Brennan and Michael Clarkin, Camroden Associates;
Timothy M. Dyess, AEERL; William Brodhead, Buffalo Homes VIIIP-2
xiii
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Correlation of Soil Radon Availability Number with Indoor Radon and
Geology in Virginia and Maryland
Stephen T. Hall, Radon Control Professionals, Inc VIIIP-3
Session IX: Radon Occurrence in the Natural Environment
Combining Mitigation and Geology: Indoor Radon Reduction by
Accessing the Source
Stephen T. Hall, Radon Control Professionals, Inc IX-1
A Comparison of Radon Results to Geologic Formations for the
State of Kentucky
David McFarland, Merit Environmental Services IX-2
Geologic Radon Potential of the United States
Linda Gunderson, U. S. Geological Survey IX-3
Technological Enhancement of Radon Daughter Exposures Due to
Non-nuclear Energy Activities
Jadranka Kovac, University of Zagreb, Yugoslavia IX-4
A Site Study of Soil Characteristics and Soil Gas Radon
Richard Lively, Minnesota Geological Survey; Daniel Steck,
St. John's University IX-5
Geological Parameters in Radon Risk Assessment - A Case History
of Deliberate Exploration
Donald Carlisle and Haydar Azzouz, University of California
at Los Angeles IX-6
Session IX Posters
Geologic Evaluation of Radon Availability in New Mexico: A Progress Report
Virginia T. McLemore and John W. Hawley, New Mexico Bureau of Mines
and Mineral Resources; Ralph A. Manchego, New Mexico
Environmental Improvement Division IXP-1
Paleozoic Granites in the Southeastern United States as Sources
of Indoor Radon
Stephen T. Hall, Radon Control Professionals, Inc.. IXP-2
Comparison of Long-Term Radon Detectors and Their Correlations with
Bedrock Sources and Fracturing
Darioush T. Gharemani, Radon Survey Systems, Inc IXP-3
xiv
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Geologic Assessment of Radon-222 in McLennan County, Texas
Mary L. Podsednik, Law Engineering, Inc IXP-4
Radon Emanation from Fractal Surfaces
Thomas M. Semkow, Pravin P. Parekh, and Charles O. Kunz, New York
State Department of Health and State University of New York
at Albany; Charles D. Schwenker, New York State Department
of Health IXP-5
National Ambient Radon Study
Richard Hopper, U. S. EPA, Office of Radiation Programs IXP-6
Session X: Radon in Schools and Large Buildings
The Results of EPA's School Protocol Development Study
Anita L. Schmidt, U. S. EPA, Office of Radiation Programs X-1
Diagnostic Evaluations of Twenty-six U. S. School - EPA's School
Evaluation Program
Gene Fisher, U. S. EPA, Office of Radiation Programs X-2
Extended Heating, Ventilating and Air Conditioning Diagnostics in
Schools in Maine
Terry Brennan, Camroden Associates X-3
Mitigation Diagnostics: The Need for Understanding Both HVAC and
Geologic Effects in Schools
Stephen T. Hall, Radon Control Professionals, Inc X-4
A Comparison of Radon Mitigation Options for Crawl Space School Buildings
Bobby E. Pyle, Southern Research Institute; Kelly W. Leovic, AEERL X-5
HVAC System Complications and Controls for Radon Reduction in
School Buildings
Kelly W. Leovic, D. Bruce Harris, and Timothy M. Dyess, AEERL;
Bobby E. Pyle, Sourthe Research Institute; Tom Borak, Western
Radon Regional Training Center; David W. Saum, INFILTEC X-6
Radon Diagnosis and Mitigation of a Large Commercial Office Building
David Saum, INFILTEC. X-7
New School Radon Abatement Systems
Ronald F. Simon, R. F. Simon Company X-8
Design of Radon-Resistant and Easy-to-Mitigate New School Buildings
Alfred B. Craig, Kelly W. Leovic, and D. Bruce Harris, AEERL X-9
xv
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Session X Posters
Design and Application of Active Soil Depressurization (ASD) Systems
in School Buildings
Kelly W. Leovic, A. B. Craig, and D. Bruce Harris, AEERL; Bobby E.
Pyle, Southern Research Institute; Kenneth Webb, Bowling Green
(KY) Public Schools XP-1
Radon in Large Buildings: Pre-Construction Soil Radon Surveys
Ralph A. Llewellyn, University of Central Florida XP-2
Radon Measurements in North Dakota Schools
Thomas H. Morth, Arlen L. Jacobson, James E. Killingbeck,
Terry D. Lindsey, and Allen L. Johnson, North Dakota State
Department of Health and Consolidated Laboratories XP-3
Major Renovation of Public Schools that Includes Radon Prevention:
A case Study of Approach, System Design and Installation, and
Problems Encountered
Thomas Meehan XP-4
The State of Maine School Radon Project: The Design Study
Henry E. Warren, Maine Bureau of Public Improvement;
Ethel G. Romm, NITON Corporation XP-5
Design for the National Schools Survey
Lisa Ratcliff, U. S. EPA, Office of Radiation Programs XP-6
xvi
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Session VII:
State Programs and Policies Relating to Radon
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VII-1
WASHINGTON STATE'S INNOVATIVE GRANT:
COMMUNITY SUPPORT RADON ACTION TEAM FOR SCHOOLS
by: Patricia A. McLachlan
Department of Health
Olympia, Washington 98504
ABSTRACT
In February, 1990, the Environmental Protection Agency awarded
the Washington State Department of Health $100,000 from the State
Indoor Radon Grants Program to fund an innovative project titled,
"Community Support Radon Action Team for Schools." The Department
of Health contributed an additional $34,000 to the project and
organized a team of public and private sector experts. The goal of
the team was to write a manual of cooperative and cost-effective
approaches school administrators could use to assess and mitigate
radon exposure in schools.
The team of federal, state and local experts from the fields
of health, education, energy, building science and codes, safety,
administration, communication, and radon testing, diagnostics and
mitigation, chose to write and evaluate the manual with the
cooperation of a school district in northeastern Washington.
The manual includes chapters on administrator's overview,
radon facts, radon awareness, radon and liability, strategic
planning, public informational materials, school radon testing,
building inspection and radon diagnostics, radon mitigation, long-
term radon management, and case studies. These chapters and the
experience gained in their application in the school district will
b« discussed.
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INTRODUCTION
Despite the identification of elevated radon exposure levels
(100 pCi/L) in some buildings in Washington State's five
northeastern counties, very few residences, schools or public and
commercial buildings have been tested or mitigated. Within the
Core Radon Program, the Department of Health (DOH), the State's
lead agency responsible for a radon program, has insufficient
resources to help school districts that want to tackle their radon
problems but lack the funds, organization, staff and technical
expertise.
DOH with its State Radon Task Force encourages state agencies,
local governing bodies and other organizations to work
cooperatively to reduce the public health risk from radon. In
discussions with personnel in the school community, government
agencies and the private radon industry, DOH found a manual was
needed to help schools resolve radon issues. Since a variety of
relevant expertise was present in Washington State, a team approach
to developing the manual had merit. EPA agreed and awarded funding
for DOH's innovative project, "Community Support Radon Action
Team."
THE RADON ACTION TEAM
The Community Support Radon Action Team, a group of public and
private sector experts, met ten times from March, 1990 to February,
1991 and numerous times in small working groups to develop the
School Radon Action Manual. The team was composed of health, radon
and building science experts from DOH, Region 10 EPA, the
Washington Energy Extension Service (WEES), the Spokane County
Health District (SCHD) and the City of Spokane Building Services
Department (SBSD). Also, Faytek, Inc., Quality Conservation and
Thomas J. Gerard & Associates, Inc. from the private sector
provided expertise on radon testing, diagnostics and mitigation,
and HVAC (heating, ventilation and air conditioning) systems,
respectively.
In addition, the school community was represented on the team
by a manager of state school facilities from the Office of the
State Superintendent of Public Instruction (OSPI); a writer and a
safety coordinator from the Education Service District 101 (ESD
101, one of nine regional agencies in Washington providing
administrative and instructional support to local school
districts); an administrator experienced in school radon testing
from Spokane School District 81 (SSD); and an administrator, a
public information officer, a supervisor of school maintenance and
an HVAC specialist from Central Valley School District 356 (CVSD).
The Northwest Regional Foundation (NRF, a private, non-profit
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corporation committed to facilitating change in communities)
provided a facilitator to help this group of people work as a team
to write the manual and evaluate its application in the CVSD.
Finally, as a legal consultant, a Washington State Assistant
Attorney General (OAG) contributed his expertise about liability.
the team process
In initial meetings, team members discussed the project goal,
participants' self-interests, the process of radon problem solving
in a school community, manual contents, working group assignments
and site selections for the case studies in CVSD. The major goal of
the team was to compile educational, problem solving and
organizational resources in the 8chool Radon Action Manual.
The manual was designed to help school personnel communicate with
their school community about radon and use internal resources as
well as the private sector to cost-effectively assess and remediate
for radon in their schools.
Radon Action Team members represented a wide variety of
expertise and self-interests. Health professionals focussed on the
need to communicate the health effects of radon exposure accurately
and effectively to the public. School administrators desired to
test, diagnose and mitigate for radon in a cost-effective manner
while informing and involving their communities. Radon testing
professionals demanded a scientific approach that complied with EPA
interim protocols. Building science professionals concentrated on
each building as an integrated system that demanded careful,
logical problem solving techniques as radon and other indoor air
quality problems were tackled. Team members decided to
cooperatively pool their knowledge and concerns in the manual
development realizing they had differences in perspectives and
opinions which would be debated during the writing process.
In fact, many vigorous discussions did take place over the
course of the year. One often debated question was: How much
testing, diagnostics and mitigation work can school personnel
accurately and cost-effectively accomplish before they call in the
private sector for help? A second question was: How can a school
district communicate about radon to its community which often wants
problems immediately solved, while the district trains its staff,
hires consultants, requests bids, raises funding and plans to
remediate radon problems as they are discovered over several years
of testing and diagnostics? Team members decided they could
provide accurate and concise guidance on such things as radon
testing options, building inspection and radon diagnostics, and
public informational materials. They concluded, however, that
ultimately it would be school administrators with an intimate
knowledge of their communities and resources who would answer these
questions.
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SCHOOL RADON ACTION MANUAL
The School Radon Action Manual contains sections designed for
school district administrators, public information officers,
building managers and maintenance personnel. The manual
organization follows a school radon action process (illustrated in
Figure 1) recommended by the team. A list of the sections with a
summary of their contents follows:
The "Administrators' Overview" includes what radon is, where
radon is found, what the health risks are and when radon was
recognized as a health hazard. Other topics are how radon enters
a building, how it is measured, how radon concentrations are
reduced and who can perform the radon testing and mitigation. In
this section, the team recommends that school district staff
involved in radon testing, building diagnostics or mitigation
attend an EPA endorsed training course. Also, it is recommended
that school district consultants show that they have successfully
participated in EPA's Radon Measurement Proficiency Program, or
employ individuals who have passed EPA's National Radon Contractor
Proficiency Program.
"Radon Facts" gives greater detail on radon discovery, radon
and radon progeny, the health effects of radon, the health risk to
children and comparisons of school to home exposures.
"Risk Awareness" deals with assessing risk, the nature of
radon risk, 4 pCi/L as an action level, the Indoor Radon Abatement
Act, the health risk to children and smokers, challenges to EPA's
risk estimates, getting to ALARA (As-Low-As-Reasonably-Achievable),
managing and communicating radon risk and the risk awareness
process.
"Radon and Liability" concludes that health hazards presented
by radon and indoor pollution in schools and public buildings may
be substantially reduced by technical analysis of the problem and
a careful administrative response from management. Failure to
initiate the analysis and respond to the problem presents the risk
of liability for any school or public institution. Suggestions for
a program that schools can develop to deal with radon and other
indoor air quality problems are given.
"Strategic Planning" deals with how a school district may
develop a plan for dealing with radon in its buildings. Topics
covered include prerequisites for planning, action steps, timelines
and financing. Formulation of a radon action team is recommended.
"Public Informational Materials" includes internal and
external communications strategies utilized by the Central Valley
School District as it dealt with radon in its schools. It includes
-------
RISK
AWARENESS
ADMINISTRATOR
OVERVIEW
RAOON
FACTS
STRATEGIC
PLANNING
NO
RECONSIDER
A 1 LA 1 fcr*
DATE
SCHOOL
RADON
ACTION
PROCESS
SCHOOL
RAOON
TESTING
BUILDING
INSPECTION
ANO RAOON
DIAGNOSTICS
RAOON
MITIGATION
SY5TEM
SELECTION
ELEVATED
TESTS
EVALUATE
DOCUMENT
ANO REPORT
TO PUBLIC
cAse
STUDIES
FIGURE t. School Radon Action Process
-------
strategies for communicating with staff, administrators, students,
parents and the news media. Sample press releases and letters are
included in this section.
"School Radon Testing" deals with testing school buildings for
radon. It provides information on qualifications necessary to
perform testing, school district requirements, testing procedures
and forms, testing methods with advantages and disadvantages, and
evaluation of testing results.
"Building Inspection and Radon Diagnostics" describes how to
inspect buildings and perform or oversee diagnostic testing for
radon entry locations. It includes checklists for review of
testing data and for mechanical and structural inspections.
"Radon Mitigation" provides strategies for mitigation if
elevated levels of radon are found in a building. Topics include
radon entry, causes of pressure differentials, variations in radon
concentrations between rooms, mitigation techniques and dealing
with contractors.
"Long-term Radon Management" provides the basics for continual
monitoring of indoor air quality, including radon, for the
district. Topics include team design, program design, public
policy guidelines and documentation.
"Case Studies" documents the application of the manual in six
schools in the Central Valley School District (CVSD). This
section describes the radon action process that CVSD employed with
the manual and team members' expertise. Based on this limited
application of the manual in one school district, the team offers
suggestions to other school districts about what worked and what
didn't work.
The "Glossary" defines key terms school district personnel
must understand to communicate meaningfully about radon as a public
health issue. The "Bibliography," a "Team Members' List" and
"Federal and State Contacts" complete the manual.
CASE STUDIES
During this project, part of the manual's school radon action
process (see Figure 1) was evaluated using six buildings in the
Central Valley School District of Spokane County, Washington. The
school community (including school board, faculty and staff,
parents and students) was informed of the project and the radon
action process by Radon Action Team members through the use of the
sections: "Radon Facts," "Risk Awareness," and "Public
Informational Materials." School personnel were trained by team
professionals using parts of the sections: "School Radon Testing"
-------
and "Buildinq Inspection and Radon Diagnostics." The manual
sections^ "Administrator's Overview, •• "Radon and Liability,"
"S^teSic Planning," "Radon Mitigation," and "Long-Term Radon
Management" were still being developed during this time so they
were not evaluated in this school district.
Selected for evaluation of the educational, communications,
Hiannostics nrocesses were three elementary schools, a
junior high school, a high school and an administration building.
Team members made presentations about the Project and the school
radon action process at meetings of the school board,
administrators, faculty, staff. Parent Teacher Association (PTA)
and press. Four junior high science instructors wrote model radon
awareness curriculum which they taught and are refining for
distribution next summer. Literature on radon was displayed and
available to staff and the public in the building reception
areas Letters were sent home to parents, and articles published
*noucnaners A spirit of openness and cooperation was
nurtured by thf radon action team and the school administrators.
The team decided to employ charcoal canisters to test the
administration building and the high school and electrets to test
the other- four schools. In both cases, school maintenance
personnel" were given training from the manual in placing the
detectors, retrieving them, and keeping records. Charcoal devices
were sent to the manufacturer's lab for analysis while electrets
were read by school personnel. Faytek, a private EPA proficient
testing company, provided training and oversight throughout the
whole testing process.
Elevated radon levels were found in the administration
building, high school, and three elementary schools. At the
writing of this paper, building inspection and radon diagnostics
are in progress by both team members and school personnel. School
personnel have provided information about building histories and
basic building operation. They have completed some initial
mitigation involving sealing cracks and adjusting HVAC systems.
Most of the detailed diagnostics is being performed by radon
professionals from Quality Conservation, EPA proficient
contractors, and a mechanical engineer from Gerard and Associates,
all team members. Quality Conservation is in the process of
developing remediation plans for two elementary schools and the
high school. At the end of the pro3ect, a cost analysis of testing
with charcoal versus electrets and testing and diagnostics using
school personnel with private sector oversight versus private
sector only will be made. Due to time and funding limitations, the
team's efforts will end after the three remediation plans are given
to the Central Valley school District.
-------
SUGGESTIONS FOR SCHOOL PERSONNEL
Although the work on the case studies is still in progress,
some preliminary and general suggestions have emerged from the
Radon Action Team's work in the Central Valley School District.
This school district is to be applauded for its progressive
approach to radon problem solving and its offer to share lessons
learned from this project with other school districts.
Suggestions are as follows:
As a part of strategic planning, the team recommends that
schools assemble a Radon Action Team which incorporates relevant
expertise from both the public and private sectors. The team
organized for this project provides a model for team member
selection (although smaller teams are appropriate for individual
school districts). It is important that regular meetings of this
team be held and that progress reports be shared with and decisions
supported by upper level administrators (school board members,
superintendents, district level administrators, and principals) in
the school district. As part of the school district's operations
strategy, it is recommended that EPA testing protocols should be
followed. Decision points and procedures for immediate risk
interventions should be developed. Thought should be given to
scheduling, and minimizing class disruptions and loss of detectors.
During the public informational process, we suggest that a
public information officer or a superintendent be the primary
contact for all information requests. This contact person should
be a team member, well-informed about radon issues, activities in
the schools and the district's strategic plan. Requests for
information should be answered accurately, openly and quickly, with
a timeline given for the radon action process ( eg. when test
results will be reported, when buildings will be fixed) . A good
relationship should be established with the press at the outset of
the process. The contact person needs to be flexible, calm and
ready to handle "incidents" with concerned individuals and groups.
Staff in buildings with preexisting indoor air quality problems may
show a heightened interest or sensitivity to radon testing. More
communication may be needed. PTA meetings work well to inform
parents and faculty. The public information officer should be
accompanied by other team members who have expertise in radon
health effects, testing, diagnostics and mitigation, to gain public
credibility through answering a broad range of questions.
Before a school district begins the radon testing process,
school personnel should evaluate the various options for testing,
considering cost-effectiveness, available internal and external
resources, liability issues and time constraints. These options
include use of private testing firms, use of school personnel or a
-------
If school personnel will be involved in
combination of the two teSting, the team suggests that school
performing school raaon ^ maintenance personnel) receive EPA
personnel (perhaps one « priVate, epa proficient testing company
approved training. Also' ^Juitant to oversee placement, retrieval,
should be empl°yedasaconits^ Quality control procedures must be
and recording of canisters and electr*et«s». if school
performed for both charco ffiU8t have training in appropriate
personnel read ®.lect5® worms and computer spreadsheets should be
analytical techniques. e accurate and complete record keeping
¦snsr ssasr~ iars s
s,r&sr srs - »»•
u.i 1 hino lnscection and radon diagnostics,
During testing, ired. Team members found that both
plans and maps are re
-------
Conservation); and Tom Gerard (Gerard and Associates). Other
important contributions were made by T.R. Strong, Robert R. Mooney,
Kate Coleman and Ed Scherieble (DOH); Dick Sovde (CVSD); and Larry
Watters (OAG).
The work described in this paper was partially funded by the
U.S. Environmental Protection Agency and is in their review
process. Therefore, the contents do not necessarily reflect the
views of the Agency and no official endorsement should be inferred.
-------
kkntuckv innovative grant
RADON IN SCHOOLS' TELECOMMUNICATION PROJECT
VII-2
by: M. Jeana Phelps, M.Ed., RT(R)
Radon Program. Radiation Control Branch
Division of Community Safety
Kentucky Cabinet for Human Resources
Frankfort, Kentucky
and
Carolyn Rude-Parkins, Ph.D.
Occupational Training and Development
University of Louisville
Louisville, Kentucky
ABSTRACT
one of the many challenge? facing the U.S. Environmental
Protection Agency and individual state radiation control programs
is to provide decision-making information and technical support
to school administrators about radon testing and mitigation in
school buildings.
This DaDer provides information on the development, delivery
« Lr»n ^niementatio11 of a model radon telecommunication
outreach program to school administrators in Kentucky and to the
following states: Alabama* Arkansas, Georgia, Louisiana,
M?rhiaan Missouri. Mississippi, North Dakota. Nebraska. New
Jersev Ohio Pennsylvania. Texas. South Carolina. Wisconsin, and
Virgin^. Virginia * «d Florida. (Figure 1)
The two hour interactive broadcast will be delivered by
satellite to all locations through the Kentucky Educational
Television Network (KET) -
Kentucky Educational Television
Star Channel Netw°rk
• Alabama
* Arkansas
* Georgia
• Louisiana
* Mississippi
* North Dakota
* Nebraska
* New Jersey
* Ohio
* Pennsylvania
* Texas
* South Carolina
* Wisconsin
* West Virginia
* Virginia
* Florida
• Louisiana
• Michigan
• Missouri
Figure s??.st^E Channel Network
St*te Contacts
-------
In schools around the world, students are "talking" to other
students they may never see; teachers are instructing students
who are not in the room; professionals are meeting with far away
colleagues without leaving their desks. Distance learning
concepts and technologies make these interactions possible.
Distance learning is defined as the application of
telecommunications and electronic devices which enable students
to receive instruction that originates from some distant
location. It involves four major concepts:
1. students are seperated from one another and from the teacher;
2. interactive two-way technologies are used to unite them;
3. the learning is planned, delivered, and evaluated by an
institution;
4. students organize themselves and collaborate around a goal
which may be theirs or the teacher's (1,2).
SEPARATED
Virtually any subject can be taught via distance learning.
During 1989-1990, the National University Teleconference Network
(NUTU) offered 94 programs, both fee-based and free. The
greatest percentage (41%) of these programs were directed to
Engineers with the remaining being delivered to: Education
(38.6%), Medical and Allied Health (27.3%), and general interest
(34.1%) (3). Distance learning provides a connecting network to
learners who may be in the next building, another city or in a
different country. Distance learning also allows the learners to
"tune-in" at a time and location convenient to their schedule.
UNITED
The key to distance learning is two-way interactive
technology. In the past, print technology and the U.S. Postal
Service delivered correspondence courses to students in dispersed
locations. Radio and telephone added an audio component and the
possibility for two-way interaction. Later, education television
broadcasts, cable programs, and video cassettes offered other
ways of distributing course materials. Interactivity was added
via telephone and then computer.
Today, computers, satellites and telecommunications
technologies such as fiber optics expand the power of older
distance learning technologies. Computers make it possible to
access electronic mail, bulletin boards, interactive computer
conferences, data bases of information and computer assisted
instructional lessons and courses. Microwave dishes and
satellite links enable the computer to reach across the street
and around the world. Telephones, fiber optics and satellites
permit one-way and two-way interactive video conferencing.
-------
Distance learning technologies fall into the categories of
video, voice and data communications. Video is the primary means
of delivery. It is the most attractive, complex and expensive.
Audio telephone delivery provides one-on-one interaction or
handles groups of three or more in different locations via an
audio bridge. Audiographic teleconferencing permits the
transmission of still images and audio signals over telephone
lines. Electronic blackboards and tablets, FAX, slow scan, and
compressed video also use telecommunications technologies.
Video, voice, and data communications can reach learners at
any time and in any place. But the real power of distance
learning lies in two-way interactive technologies (2). The
reason for this is the capability for interpersonal
communication. one-way systems leave the learners passive,
uninvolved and isolated. Two-way systems let them actively
exchange ideas, information and feelings. It puts high touch
into high technology. They can reach out and touch a real
someone.(2)
KENTUCKY EDUCATIONAL NETWORK (KET)
Kentucky is the first state in the nation to fund and
construct a statewide telecommunications delivery system. KET
was established by_ the Legislature in 1968 to provide
instructional services to teachers. The Satellite uplink costs
$500,000 and $2,000 for each school downlink, it is the largest
system in the nation. The KET Star channel system consists of a
transmitting and receiving site at the KET Network Center in
Lexington, Kentucky and has more than 1,300 receiving sites (down
links) located throughout Kentucky at public schools. The KET
satellite can uplink programs not only to Kentucky schools but
also to schools throughout the nation (Figure 1 and Figure 2).
Statewide Telecommunications Service To:
A Tranf""0"*""
public oduco®*1
^UtjtUOOlU
Elementary/Secondary Schools
Vocational Schools
Colleges and Universities
Figure 2• *ET Reaches aU Public Schools in the State
-------
This potential nationwide KET linkage will allow the Kentucky
radon program to offer the "Radon in Schools" broadcasts to
radiation control offices and education departments in the
following states.
Alabama
Georgia
Michigan
Mississippi
Nebraska
Ohio
Texas
Wisconsin
Virginia
Kansas. Oklahoma, Tennes
currently KET STAR Channel p
states can be arranged.
Arkansas
Louisiana
Missouri
North Dakota
New Jersey
Pennsylvania
South Carolina
West Virginia
Florida
, and North Carolina are not
icipants. but linkage to these
TARGET AUDIENCE
The radon program, funded through the U.S. Environmental
Protection Agency, State Indoor Radon Innovative Grant, will
apply KET's high technology approach to providing radon
information to school administrators, school building managers,
daycare operators, and others engaged in managing buildings where
citizens learn and work.(Figure 3)
Once the broadcast dates have been scheduled and
pre-broadcast materials developed, all state radiation control
offices, radon programs, state departments' of education and
other target participants will be invited to link up and take
part in this project.
School
Facility
Managers
STAR
School
Administrators
Private/Public
KET
State
Licensed
Daycare
Centers
Radon Testing
and
Mitigation Info
To
SATELLITE
Colleges
Universities
Technical School
Administrators
Figure 3: KET/Radon Target Audience
-------
For Kentucky public school officials, the radon in schools
broadcast will arrive soon after they receive confirmatory radon
measurements for their building(s). For others such as daycare
and nursing home operators, the information will arrive as they
begin to consider how to go about testing and mitigating their
buildings.
By using the Star Channel satellite and distance learning
concepts, the radon program staff can reduce the need to travel
statewide to disseminate radon information to these groups. An
additional benefit of this communication media is that the
audience is exposed to a consistent message with minimal
presenter bias.
KET-RADON PROJECT GOALS
The second KET/Radon Innovative grant goal will go beyond the
initial broadcasts to research the potential for using
telecommunications to deliver information about radon. To do
this, the KET project staff will investigate existing
telecommunication networks and apply this knowledge to the
delivery of radon information and technical training. Another
aspect to be investigated will be the possibility of linking the
USEPA Regional Radon Training Centers, through a central training
delivery system with on-site training center faculty in
designated locations (Table 1).
TABLE l: KET/RADON INNOVATIVE GRANT GOALS
KET - Radon Project Goals
• Design and Deliver two Radon Programs
utilizing the Star Satellite and
telecommunications.
• Investigate the potential for using KET Network
to deliver Radon information, Training, and
Continuing Education.
-------
SCHEDULED BROADCASTS
The Spring broadcast date is expected to be scheduled prior
to the time school officials finalize their 1991-1992 budget
requests. Hopefully, the timing of the broadcast and the
technical information provided, will be sufficient to allow
school officials to request funding for radon testing and
mitigation*projects (Table 2).
TABLE 2: BROADCAST SCHEDULE
Radon Broadcasts
• Spring 1991 - Testing
• Fall 1991 - Mitigating
The Spring broadcast will emphasize radon testing protocols
for schools and illustrate ways to communicate cadon risk
information to parents, staff, children and the public (Table 3).
TABLE 3: SPRING BROADCAST DESIGN
Spring 1991
Broadcast Design
• Testing for Radon in Schools
• Decision steps based on
• Initial Screening Measurements
• Confirmatory Measurements
• Risk Communication Suggestions
• Resources Available
• Live Panel of Radon Experts for Teleconference
-------
Kentucky school representatives, experienced in radon testing
and mitigation in their own school building(s), will share
insights and lessons learned. These segments win be pre-taped
in the actual school setting. Also, the radon school based
outreach program being implemented by the Jefferson County Public
School District and Jefferson County Parent-Teacher's Association
will be highlighted (Table 4).
TABLE 4: FALL BROADCAST DESIGN
Fall 1991
Broadcast Design
• Mitigating for Radon in Schools
• Decision Steps
• Risk communication suggestions
• Resources Available
• Live Panel of Radon Experts for
Teleconference panel
The Fall Radon in Schools broadcast will provide school
mitigation information. Again. Kentucky school representatives
will share their experiences in an attempt to communicate the
message that radon issues are manageable within a school setting
and that there are others who have survived the process (Table 4).
Each two hour broadcast will feature a "live" interactive
question and answer period for the last 30-40 minutes of the
program. A panel consisting of radon experts from U.S. EPA and
other agencies will respond »on air" to participants' questions
The audience will be provided with an 800 telephone number to the
KET studio and encouraged to call in with their questions. The
BOO call-in number will remain active for one hour after the
broadcast. Trained radon staff will answer the incoming calls
write out the questions and route them to a panel member.
A panel member the question aloud and provide an
answer or refer the ca*additional resources. Any caller
who does not have their question addressed on live broadcast will
receive a written jnswer by mail following the program. Callers
will not be identified by n*me or school and their voices will
not be aired.
-------
The entire broadcast plus the live panel call-in segment will
be taped for future broadcast schedules. Individual tapes will
be made available through a loan program (Figure 4).
BROADCAST PRODUCTION
SO
1. Imtructkffl b
preeented before a
camera in the KET
Audio in Lexington.
2. TeievWon triiumkfkxi
U beamed to aalelllte
In earth orbit.
7. Expert panel
monitor! audience
qucation* (voice II
data) and provider
advice.
I
Distance Learning
Process
6. Information from
telephone l> delivered to
the ftudlo by lei •(> hone
"f
3. Relayed to a
•chooi'l
•ateillte dtoh.
4. The audience watchei
the lemon on
tdevidon.
St Omight facUUtatkm.
Figure 4: Distance Learning Process
Pre-broadcast activities can be divided into two major steps;
audience preparation and broadcast production processes. In
regard to the participants, the State Department of Education,
Human Resources Licensing and Regulation Department, and KET will
assist by providing mailing labels for the target audiences. The
project staff person, in coordination, with the USEPA and KET and
others, will prepare the broadcast design. KET staff will take
the lead in taping and editing broadcast visuals. Field taping
of actual school settings is planned as part of a pre-production
activity. Existing video productions may also be integrated.
Other pre-broadcast activities include sending a radon
resource literature package along with each invitation. In each
school district, a KET receiving school will be identified as a
radon resource broadcast center. These resource centers will
provide on-site facilitation during and after the broadcast by a
"radon trained" resource person. County Extension Agents, school
representatives, local health officials, and others with
demonstrated knowledge of radon testing and mitigation will be
designated to serve as on-site facilitators. The facilitators
will receive a pre-broadcast orientation to ensure statewide
consistency of information. For security reasons, all non-school
related participants (daycare operators, etc.) will be assigned
to a resource center. Closest to their home/work.
-------
EVALUATION
The nature of this project requires an extensive system of
checks and balances at each phase of development. This will be
provided by the KET staff assigned to the project, as well as the
project designated radon staff person. USEPA Region IV staff,
and Regional Radon Training Center staff will provide ongoing'
assistance and review. An in-state work group will also be
assigned to on-going evaluation. Members of this group will
include, staff from the radon program. State Department of
Education; Jefferson. Fayette, and Warren County School
Districts; University of Kentucky Cooperative Extension Service.
Kentucky Parent-Teachers Association, and others.
An immediate post-broadcast evaluation questionnaire and a
six week follow-up will be administered to all participants. The
results from the immediate and delayed evaluation will serve to
measure the degree of change in participant attitude regarding
radon.
ACKNOWLEDGEMENTS
Special thanks to Tim Tassie. KET Acting Deputy. Executive
Director of Broadcasting, for giving flight to the radon distance
learning ideas outlined in this paper.
Also, to Paul Wagner/Patsy Brooks. USEPA Region IV, James
Vaughn. Jefferson County Public School District, Sharon Solomon
and Virginia Maurer. Parent Teachers' Association of Kentucky.
Jim Judge. Ky Department of Education, and to Chick Craig and'his
team who have provided assistance to Kentucky schools.
References
1. Carl. D.R. (1989). A response to Greenville Rumble's "On
defining distance education". American Journal of Distance
Education. 3(3). 65-67.
2. Rude-Parkins, Ph.D.. Carolyn, (1990) Distance Learning
Technology and Education: Key Ideas for Kentucky Educators.
Kentucky Department of Education.
3. National University Teleconference Network (NUTN), NUTN News.
Vol. 8, No. 3. Winter 1990.
-------
Appendix A
JEFFERSON COUNTY SCHOOL DISTRICT
AND
RADON PROGRAM
1. Work cooperatively to establish a radon comunication outreach program
through the school to parents, staff, and students.
2. Promote the Jefferson County School District radon testing project and the
communication outreach program as a model for other school districts in the
state and the nation.
MODEL COMMUNICATION OUTREACH
Audience
School Administrators Building Maintenance Personnel
Teachers Ancillary School Staff
Parents Parent-Teachers Association
Students
Message
Long-term exposure to elevated levels of rdon gas is associated with increased
risk of developing lung cancer.
Testing for radon gas is easy and mitigation methods are effective.
All homeowners should test their homes. Schools, daycares, public and commerical
buildings should also be tested.
If elevated levels are discovered, action should be taken to reduce the levels.
-------
RADON COMMUNICATION OUTREACH PROGRAM THROUGH SCHOOLS
Audience
Type of Communication
Message
School Administrators
Building Maintenance
Personnel
Technical/Support
and Motivational
- Testing Protocols
- Decision process
after testing
- Mitigation strategies
• Technical assistance
- Public disclosure
- Encourage them to
test their homes
Teachers
Ancillary School Staff
Informational and
Motivational
-Levels of radon in
school, by room
- Mitigation strategy
- Encourage them to
test their homes
Parent-Teacher's
Association
Informational and
Motivational
- Levels of radon in
school, by room
- Mitigation strategy
- PTA can help school
administrators to
reach parents with
radon information
- Encourage them to
test their homes
Parents Informational and -Levels of radon in
Motivational school, by room
-Mitigation strategy
- Encourage them to
test their homes
Students Informational and - Facts about radon
Motivational and indoor air quality
- How to improve air
quality
fnmmi miration Information Pmvirintt 1nr Farh firm in
Method
Kentucky Educational
Television-Radon in
Schools Broadcast
Spring/Fall 1991
- Dissemination of
informational literature
-Presentations through the
Kentucky Education
Association
- Presentation at State
and District Meetings
and Workshops
- Assistance to individual
schools/districts
- PTA host Radon Awareness
Program
-PTA distribute radon info
to parents
- Host testing campaigns
- District/School/PTA
sponsored radon awareness
programs
- Distribution of radon
literature through PTA/
District office
• American Lung Association
lesson on radon in
"Growing Healthy"
curriculum
-Weekly Reader Poster
C
-------
VII - 3
REGULATION OF RADON PROFESSIONALS BY STATES: THE CONNECTICUT
EXPERIENCE AND POLICY ISSUES
Submitted by:
Alan J. Siniscalchi, M.S., M.P.H. (1); Zygmunt F. Dembek, M.S. (1),
Nicholas Macelletti, M.S. (1); Laurie Gokey, M.P.H. (1); Paul Schur,
M.P.H. (1); Susan Nichols, B.S. (2); and Jessie Stratton, B.S. (3)
(1) State of Connecticut Department of Health Services
(2) State of Connecticut Department of Consumer Protection
(3) State Representative, Connecticut General Assembly
ABSTRACT
The desire of state governments to provide information on proficient
radon professionals to their citizens has resulted in a variety of
informational and regulatory programs. The State of Connecticut has
developed a new registration program for radon professionals, pursuant
to Connecticut Public Act 90-321, that combines requirements for
successful completion of both state registration and federal proficiency
programs in order to be listed. Under this program, radon testers and
testing companies are required to successfully participate in the
current round of the EPA Radon Measurement Proficiency (RMP) Program.
Radon mitigation contractors must successfully participate in the Radon
Contractor Proficiency (RCP) Program and register with the Department of
Consumer Protection. Radon Diagnosticians are required to successfully
participate in both the RMP and RCP Programs. The process by which
Connecticut developed this program and recommendations for EPA policy
changes are discussed.
-------
INTRODUCTION
The State of Connecticut Department of Health Services (DHS) began
receiving inquiries on radon and requests for information on radon
professionals soon after high levels of radon were discovered in a home
in Pennsylvania. Many of the callers requested our recommendations for
radon testing companies and mitigation contractors. Most callers
wanted information on what types of testing services were available,
what prices were reasonable, which companies had the most experience
and whether they could conduct the test themselves. Callers who had
already tested asked for information on mitigation systems and lists of
"approved" mitigation contractors. Some of the better informed callers
also asked about whether it is appropriate for the same company that
conducted the radon test to also conduct the mitigation °Peration. In
time, other consumers also reported problems with the radon testing and
mitigation companies.
The DHS response to these requests has evolved through a number of
changes. These changes have included both the information provided on
radon assessment and control and the means by which we regulate radon
professionals. Our ultimate goal is to provide sufficient information
to Connecticut consumers to enable them to make informed choices on
testing and mitigation services.
This paper will outline the evolution of radon professional
regulation in Connecticut, provide recommendations for other state
programs, and propose changes for the EPA proficiency programs.
EARLY GUIDANCE ON RADON PROFESSIONALS
The DHS first attempt at providing guidance to Connecticut
consumers on radon professionals was the development, in 1985, of a
list of radon testing companies. The information was obtained from
results of an early round of the EPA's Radon Measurement Proficiency
(RMP) Program. The DHS determined that additional information on both
the types of testing services offered by each company and the price of
each testing service would also be beneficial. Information on DHS
recommendations regarding screening devices and procedures was also
included.
During 1986 the DHS provided the public with a list of mitigation
contractors used by the EPA in the northeast since little information
was available on Connecticut mitigation companies. As mitigation
companies became established in Connecticut, the DHS expanded the list
to include information on mitigation company services. Since this list
of contractors was not derived from a state or federal proficiency
program, disclaimers were added to warn the public that the DHS could
not be responsible for a company's performance.
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During 1986-88 the DHS prepared additional informational material
on radon exposure in Connecticut that was mailed in response to
telephone inquiries on radon testing. This material included fact
sheets summarizing the results of the various statewide radon surveys,
and the two EPA radon pamphlets (1,2).
In August 1987, the DHS held a news conference to announce the
results of our second statewide survey. At this conference the
Department recommended that all Connecticut citizens test their homes
for radon regardless of the geographic area of their residence, since
our surveys to date had revealed the potential for high levels of radon
in all areas of the state. The DHS formally organized a Radon Program
in December 1987 to publicize these recommendations and conduct
additional surveys. A third survey revealed consistent results in the
percentage of homes (20%) with radon levels in excess of the U.S. EPA
guideline of 4 picocuries (pCi/L) per liter (3,4,5). These results
further emphasized our recommendation that all Connecticut residents
test their homes for radon (3,4,5).
During 1989, a second state agency became increasingly involved in
assisting Connecticut consumers in evaluating radon professionals.
This agency, the Department of Consumer Protection (DCP), recommended
that individuals offering mitigation services register as "home
improvement contractors." This existing DCP registration program
provided consumers with additional protection in the form of the "Home
Improvement Guaranty Fund" with monies that can be used to correct
poorly installed or unfinished mitigation systems.
During this time, the Radon Program greatly revised the format of
how information on radon is provided to Connecticut residents. This
new approach included the development of two information packets.
Information packet "A" included a list of testing companies, a fact
sheet and the EPA pamphlet "A Citizen's Guide to Radon" (1).
Information packet "B" included the EPA pamphlet "Radon Reduction
Methods A Homeowners Guide" (2), and the list of diagnostic services
and mitigation contractors. Although the DCP registration procedures
for mitigation contractors was not mandatory at this time, the DHS
added a notice to the contractor list advising consumers of the
benefits of this program. Table 1 summarizes the other registration
requirements and recommendations. It should be noted that while the
DHS Bureau of Laboratory Services had existing regulatory authority to
require registration of testing laboratories, the DHS could not require
mitigation contractor registration. During early 1990 the Radon
Program also recommended that consumers select mitigation contractors
that had successfully participated in the EPA Radon Contractor
Proficiency (RCP) examination.
REGISTRATION REQUIREMENTS AFTER OCTOBER 1990
Many consumers were not satisfied with the status of our radon
professional lists since these lists did not require contractors to
demonstrate competency by completing a proficiency examination or
program.
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A number of Connecticut State Representatives and agency staff began to
independently suggest alternative approaches toward a more formal
regulation of radon professionals. Many of these alternative
approaches called for mandatory certification or registration
programs. A, proposed bill was submitted by the Conecticut General
Assembly's General Law Committee that asked for a mandatory licensure
program for all radon professionals. This proposed program would have
required individuals offering radon testing, diagnostic or mitigation
services to obtain a license from the DHS, that would be renewable on
an annual basis. While the bill would have offered consumers better
protection against fraudulant radon professionals than a registration
program, it would have required additional agency staff to implement.
The DHS testified against the bill, pointing out that due to fiscal
constraints and a lack of staff it would not be possible to implement
the legislation if it was enacted.
TABLE 1. REQUIREMENTS FOR LISTING OF RADON PROFESSIONALS
IN CONNECTICUT PRIOR TO OCTOBER 1990
Professional Class
Requirement Testing Diagnostics Mitigation
primary and
secondary
Department of Health
Services (DHS) Registration
EPA Radon Measurement
Proficiency (RMP) Program
EPA Radon Contractor
Proficiency (RCP) Program
Education
Department of Consumer
Protection (DCP) Registration
Yes Yes Yes
Yes No No
No Rec. * Rec.
Rec. Rec. Rec.
No No Rec.
*recommended
One of the authors (Representative Jessie Stratton) began work on
an alternative proposal that would increase the Department's ability to
regulate radon professionals at little cost to the agency. After
meeting with the representatives of appropriate state agencies
(including the other authors) a bill was proposed to accomplish these
goals using a more formal registration program. This proposed bill
survived various committee meetings and hearings and was signed into
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law by Governor William A. O'Neill on May 3, 1990. The requirements of
Public Act 90-321 "AN ACT CONCERNING PERSONS WHO TEST FOR OR MAKE HOME
REPAIRS TO ELIMINATE THE PRESENCE OF RADON GAS AND DIRECTING THE
DEPARTMENT OF HEALTH SERVICES TO ADOPT REGULATIONS ESTABLISHING SAFE
LEVELS OF RADON IN POTABLE WATER AND PAYMENTS FROM THE HOME IMPROVEMENT
GUARANTY FUND" became law on October 1, 1990. This bill stated that
"the Department of Health Services shall publish a list from time to
time of: companies that perform radon mitigation or diagnosis; primary
testing companies and secondary testing companies."
Table 2 summarizes these new requirements.
TABLE 2. REQUIREMENTS* FOR LISTING OF RADON PROFESSIONALS
IN CONNECTICUT AFTER OCTOBER 1990
Professional Class
Requirement Testing Diagnostics Mitigation
primary and
secondary
Department of Health Services Yes Yes Yes
(DHS) Registration
EPA Radon Measurement
Proficiency (RMP) Program Yes Yes No
EPA Radon Contractor
Proficiency (RCP) Program No Yes Yes
Education EPA "EPA "EPA
Measurement** Approved" Approved"
Department of Consumer
Protection (DCP) Registration No No Yes
* Under Connecticut Public Act 90-321
** Required by the DHS Bureau of Laboratory Services only
One should note the most significant changes relate to the
registration process for radon professionals. Diagnosticians and
mitigation contractors are now required to fulfill federal proficiency
requirements by successfully participating in the RCP Program in order
to be listed by DHS. This requirement of successful participation in
the RCP Program established a minimum level of proficiency for radon
contractors.
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,, , , , both radon testing and diagnostic services are
Individuals of * successfully participate in the federal RMP
specifically r«quired to ^ ^ ^ Pft ,0.321
Program to be listed by
*.• ¦? anq and mitigation contractors are required to
Beth diagnosticians^ ^ speclfled ln th> bm ^
fulfill an e uca °*.viat diagnostic specialist:s and the on-site
requirement states attended a program approved by the United States
supervisor must have atC~\ „v 6
Environmental Protection g
* *.4 „Hnti contractors are required to register with the
Final y, m g t contractors." This requirement was added to
DC? as "home improvement ^ ConnecticUt resldents
retaining the
the legislat on o eation contractors will be afforded the same
services of ra on m COIisumers using the services of any other home
protection ava a This protection can include receiving funding
to^complete unshed' installations or correct problem systems.
PROBLEMS ENCOUNTERED WITH THE IMPLEMENTATION OF PUBLIC ACT 99-321
The authors have documented the following problems in the
implementation of PA 90-321. The first problem relates to the bill's
reference to "EPA-approved courses in outlining the educational
requirements for the three radon professional groups. This term,
suggested by EPA staff atu* others, referred to courses offered by EPA
contractors including the newly organized Regional Radon Training
Centers. It was chosen to avoid the resource intensive problem of state
agency approval of source providers.
A number of radon professionals who wished to be listed by the state
asked if courses they ha<* taken from private vendors were considered
"EPA- approved". Inquiries to EPA revealed that they did not
"approve" any radon courses at that time, although they did endorse the
courses offered by the Regional Radon Training Centers.
A second problem relates to the infrequent review periods or
"rounds" offered by che ^PA Radon Measurement Proficiency (RMP)
Program. Public Act 90-321 now requires both primary and secondary
testing companies and diagnosticians to have "successfully completed"
the RMP program in ofd©* to "e listed. Therefore, newly organized
companies must wait up 1:0 a year or more for the next test round prior
to being listed.
A third problem the requirement of individuals who wish
to be listed as offer*-11® ices as a radon diagnostician participate
in both the EPA RMP pr°£Ua*nf Rad°n Contractor Proficiency (RCP)
Program. The final J °* tJe bil1 allowed any RMP participant
including secondary c°mPorilv . ° e listed as a diagnostician. The
authors have found ttl*Cdon jL °Be Co®panles with instruments capable of
performing real-time ** thes_a.,^reiMmts a™* successfully participating
in the RMP Program wic" nstruments can conduct accurate
diagnostic evaluation®*
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A forth major problem relates to the program's design as a listing
rather than a registration program. While the program places little
demand on the Department, it allows radon professionals to conduct
business without requiring proof of proficiency and training.
SUGGESTED CHANGES IN EPA POLICY TO ASSIST STATES IN THE REGULATION OF
RADON PROFESSIONALS
The Department's preliminary experience with PA 90-321 has already
modified the author's thoughts on the definition of the model radon
professional registration program. The following changes are suggested
to aid states in the development of their radon programs. These
suggestions include both changes in EPA policy and recommendations for
states in their interpretation of EPA policy.
Most changes are related to the educational requirements. Table 3
lists recommended educational requirements which call for "EPA-
equivalent" radon training courses specifically designed for radon
testers and mitigators. EPA-equivalent being defined as having a course
content based on courses offered by the EPA or by the EPA Regional Radon
Training Centers.
The change in language from "EPA-approved" to EPA-equivalent will
more accurately reflect the current EPA policy on approval of training
providers. At this time the EPA only approves providers of the
"hands-on" mitigation training course (see below).
TABLE 3. RECOMMENDED REGISTRATION REQUIREMENTS OF RADON PROFESSIONALS
BY STATE AND LOCAL GOVERNMENTS
Professional Class
Requirement
Testing Piflsnpsticg MitigaUPn
primary and
secondary
Health Agency
Registration
Yes
Yes
Yes
EPA Radon Measurement
Proficiency (RMP) Program
Yes
Yes
No
EPA Radon Contractor
Proficiency (RCP) Program
No
Yes
Yes
Education
EPA-Equivalent EPA-Equivalent EPA
Measurement Measurement & Equivalent
Mitigation Mitigation
Consumer Agency Registration No
No
Yes
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Ideally the EPA would determine if a course provider is offering an
EPA-equivalent course. EPA staff would review new course offerings
submitted by the providers and make a determination of "equivalency".
The EPA could also develop a model accreditation program for radon
course providers. State agencies could determine if a course is
considered EPA-equivalent by comparing the course outline to the EPA
accreditation model. States with limited resources devoted to radon
issues can make this determination by simple comparison of the course
outline.
The measurement course should consist of a one day program while
the mitigation course would include a "hands on" training component. A
list of approved courses that include this "hands on" component will be
maintained by the EPA. This course will include actual practice in
assembling radon mitigation systems. Diagnosticians would be required
to complete both courses, since they must be both proficient with
testing methods and knowledgeable about mitigation systems.
A second proposed change would require diagnosticians to
participate in the RMP Program as a primary company using a radon
testing device capable of obtaining real-time pinpoint radon
measurements. This type of device is needed to conduct accurate
diagnostic evaluations of homes and other buildings. This requirement
would ensure that diagnosticians will not try to conduct diagnostic
radon measurements with passive radon detection devices.
Perhaps the most significant changes would have these requirements
mandated not only for professionals who wish to be listed, but for all
professionals conducting business in a state.
SUGGESTIONS FOR THE EPA RADON MEASUREMENT PROFICIENCY (RMP) PROGRAM
The EPA's Radon Measurement Proficiency Program has proven
extremely useful for states such as Connecticut in providing
information on competent radon professionals. The authors have
identified a few minor changes that would improve the RMP's Program's
ability to provide useful information to states. These changes are
summarized on Table 4.
The most significant changes again relate to educational
requirements. The authors recommend both prerequisite and continuing
education requirements for all radon testing company personnel involved
with placement and retrieval of radon measurement devices. This
requirement will help to ensure that accurate testing procedures are
followed by professional radon testers. In addition, laboratory
directors will be required to complete a course on techniques and
procedures used in radon analysis. This requirement will ensure that
accurate analysis will be conducted by using appropriate quality
assurance techniques. Both a continuous RMP Program application
process and a continuous randomly selected blind testing are also
recommended. A continuous testing round policy will allow newly-formed
companies to immediately participate in the RMP program. The current
system of periodic "test rounds has resulted in waiting periods of up
to one year. The continuous blind testing plan will ensure that
laboratories maintain a hig^ level o£ Proficiency throughout the year.
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TABLE 4. CURRENT AND RECOMMENDED REQUIREMENTS FOR RADON TESTING
COMPANIES PARTICIPATING IN THE U.S. ENVIRONMENTAL PROTECTION AGENCY
(EPA) RADON MEASUREMENT PROFICIENCY (RMP) PROGRAM
Company Type & Requirements
Current
Recommended
PRIMARY COMPANY:
EPA Lab. Analysis*,
Education
None
EPA Measurement** or
Equivalent
QA Program (Analysis)
Yes
Yes
Chamber Testing (Submitted)
Yes
Yes
Chamber Testing (Blind)
Selected
Random (year-long)
(test round
period only)
SECONDARY COMPANY:
Documentation of Approval
Listing Only
Yes
by the Primary Co.
Education
None
EPA Measurement**
or Equivalent
QA Program (Sampling)
No
Yes
Chamber Testing (Blind)
No
Random (year-long)
* Prerequisite and continuing educational requirement for laboratory
director only
** Educational requirement for all staff involved with testing device
placement
and retrieval
RECOMMENDATIONS FOR THE EPA RADON CONTRACTOR (RCP) PROFICIENCY PROGRAM
The authors have found the EPA Radon Contractor Proficiency Program
(RCP) to be a useful addition to the RMP Program. We have some minor
recommendations for improving this program's value in providing
information to consumers who wish to contract for installation of
mitigation systems. Table 5 summarizes these changes which again
emphasize prerequisite and continuous educational requirements. The
authors have recommended that the EPA emphasize the separation of the
radon diagnostician and mitigation contractor services. This
separation should be used in both the registration requirements of the
RCP Program, where the Radon Program would recommend a separate
listing, and within the text of EPA literature on radon reduction
techniques (6,7).
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« _ rhanee is needed can be seen
An example of a do^e^o^e„AppUcation of Radon Reduction
in Section 4.1 of the entitled "Choice of Diagnos iclan/Miti-
Methods" (7)- Thi® f^lgnostician but does not emphasize the
gator," describes the diagno
distinction:
, r-ilv responsible for the diagnosis of the problem
"The person primarily J „ The rson who will be primarily
is called the installation, and post-installation
responsible for the des B ^u
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TABLE 5, CURRENT AND RECOMMENDED REQUIREMENTS FOR RADON DIAGNOSTICIAN
SPECIALISTS AND MITIGATION CONTRACTORS PARTICIPATING IN THE U.S.
ENVIRONMENTAL PROTECTION AGENCY (EPA) RADON CONTRACTOR PROFICIENCY
(RCP) PROGRAM
Professional Class and
Current
Recommended
Requirements
Diagnostician:
Prerequisite Education
No*
EPA Measurement and
Mitigation Courses
Participation in the
or Equivalent
EPA Radon Measurement
No*
Yes
Proficiency (RMP) Program
Participation in the EPA
No*
Yes
Radon Contractor Proficiency
(RCP) Program
Continuing Education
No*
Yes
Mitigation Contractor:
Prerequisite Education
Rec.**
EPA Mitigation
Course*** or
Equivalent
Participation in the EPA
Yes
yes
Radon Contractor Proficiency
(RCP) Program including use of
the RCP Guidelines (see text)
Rec.
Yes
Continuing Education
Rec.**
Yes
* Current EPA proficiency programs do not recognize diagnostic
specialists as a separate professional class
** Will be required after July 1991
*** Required for on-site supervisor only, recommended for all staff
Rec. - Recommended
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references
/ct>A\ a citizeri's Ruide to
t „ s. Environmental it'. EPA-8^ U.S.
radon. What it is and «hat Cincinnati, Ohio, August 1986. 14
Environmental Protection Age
PP' . n metbods A homeowners guide RD.68l U.S.
2. U.S. EPA. R.don «^«»gency. Cincinnati, Ohio, July 1989, 24 pp.
Environmental Pro
r j Rothney, L.M.. , SiniscaK*1' A.J . Brown,
3 Toal, B.F., Dupuy C.J.. exposure assessmenC - Connecticut.
D,R. and Th0®a®' ^it weekly Report (MMWR) 38:713, 1989.
Morbidity and Mortality
» rhnev L.M-. Toal, B.F., Thomas, M.A., Brown,
4. Siniscalchl, A. J ¦ ' ^ ^ ^n
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TITLE: New Jersey's Program - A three-tiered Approach to Radon
AUTHOR: Jin a. Lapoti, New Jersey Department of Environmental Protection
This paper was not received in time to be included in the
preprints and the abstract was not available. Please check your
registration packet for a complete copy of the paper.
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Session VII:
State Programs and Policies
Relating to Radon -- POSTERS
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vi ip-
Quality Assuranc© - The K©y to Succossful
Radon Programs in the 1990's
Raymond H. Johnson, Jr., Certified Health Physicist
Key Technology, Inc.
P.O. Box 562, Jonestown, PA 17038
In order to reach EPA's goals for radon abatement in the United States during this
decade Federal and state programs, as well as those of private industry will need a strong
commitment to quality. To deal with public apathy and to assure credibility for convincing
uovemment agencies and school districts to take action will require a partnership for
quality among those agencies, professional and trade associations, and the radon industry.
Most people will not commit their hard earned resources when they perceive poor quality
or uncertainty in health risk analyses, radon measurements or mitigation technology.
During the 1980's, thousands of companies entered the radon industry. Many of
these businesses have succeeded, many have failed. The factor determining success or
failure was most often a matter of quality; quality of management, quality of service,
quality of products, quality of analyses, and quality of technology. Continuing success for
these companies will depend on their emphasis on quality in every aspect of their business.
This statement also applies to Federal and state programs. Successful programs will
implement the principles of good quality assurance, not just m their measurement
programs but also in their customer service programs, their written and verbal
communications, their staff training, in production and sales, in accounting, in
management, in state-of-the-art technology, in ethics, and in professionalism.
For credibility with the general public, Federal and state programs need to work
with the private sector to assure the highest quality in communications. With so many
demands on their attention, an increasingly knowledgeable public will not respond to
anything less than the highest quality in print, voice, or video media. Customer service for
both the government and the radon industry will need to be prompt, efficient, courteous,
careful knowledgeable, cheerful, and follow-up on commitments. The public has no
patience for anything less in service. Staff people must be well trained. Companies in the
radon industry must realize that radon measurement and mitigation are sciences that
require careful attention to technology. Learning this technology and keeping up with new
developments requires a commitment to training.
Successful federal and private programs will need high quality management. The
public will not support programs when they have doubts about the integrity, ethics,
professionalism, and competence of management. It is up to management to set the
standards for quality and to demonstrate quality by their own example. To achieve a
quality revolution in radon abatement programs will require that management at every
level become obsessed with quality- A commitment to quality means that quality is at the
top of every agenda. It means insisting on quality in every aspect of radon programs. It
means measuring every action, service, or product for quality, and constantly striving for
improvements. It means training everyone to assess quality and establishing rewards for
quality. It means involving all the players in the government, professional, and private
sectors. Furthermore, quality implement never ends. To recognize and implement all of
these attributes of quality program 1S the surest road to successful radon programs in the
1990's.
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Radon In Illinois; A Status Report
by: Richard Allen
Melanie Hamel-Caspary
Illinois Department of Nuclear Safety
Springfield, Dlinois 62704
ABSTRACT
The Illinois Department of Nuclear Safety (IDNS) has performed radon screening
measurements in approximately 4,100 homes in 98 counties. Results indicate about 39 percent of
the basements tested have radon levels that exceed the U.S. Environmental Protection Agency
(EPA) guideline of 4 picocuries per liter (pCi/L) and 1 percent have levels greater than 20 pCi/L.
About 11 percent of first floor areas tested have levels greater than 4 pCi/L and less than 1 percent
have levels greater than 20 pCi/L. In total, about 31 percent of all homes tested have radon levels
greater than 4 pCi/L. If these results represent the entire state, this could mean as many as one
million homes in Illinois have levels above EPA guidelines.
The screening program has not indicated any areas in Illinois that face a serious health risk
from radon, but there are some areas with a significant percentage of homes with screening results
in excess of 4 pCi/L, which merit additional study. Radon may, however, cause significant
economic problems for those homeowners with homes greater than the action level. Comparisons
between house construction characteristics and radon concentrations show no particular feature or
combination of features clearly contributes to high radon concentrations.
Although radon concentrations in Illinois are not as high as in some other states (e.g.,
Pennsylvania), there is still the potential for a health hazard needing to be addressed by IDNS and
other agencies. Publicity has increased public concern about radon, proper methods for
measuring radon levels and the ability of private companies to provide effective services for
reducing levels of radon. There is also considerable concern over the need for and quality of radon
measurements conducted when required for real estate transactions. IDNS is assisting the public in
coping with these issues. Additional efforts which should be undertaken by IDNS include
follow-up studies in neighborhoods identified as potentially exhibiting elevated levels of radon,
and the sponsorship of a training and certification program for radon mitigation contractors.
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introduction
Rprause of the significance of radon, Governor James R. Thompson established a task force
in June 1986 to investigate the problem of indoor radon in Illinois and report its findings and
recommendations The task force recommended that IDNS be designated the lead agency in the
recommen t S • . an(i coordination of a comprehensive statewide indoor radon
monitoring program. Since the task force recommendations were announced IDNS has conducted
studies to 1 locate houses in Illinois with high radon levels; 2. estimate the number of houses m
Illinois that S have elevated radon levels; 3. assess the range of indoor radon exposure to
Illinois citizens- and 4 determine if any geographic regions that, because of particular geological or
!te3Si h.». gSTr potential Fo increase public radon exposure (1). The current Illinois
radon program also addresses the question of radon exposure potential m nonresidential structures
snrh as schools and is involved in radon reduction projects, public education programs, and
Sng and registering individuals that place radon detectors in stnictures.
NOTES ON 1990 UPDATE
This report is an update of the November 1988 version of "Radon in Illinois, A Status
Report" (2) The Radon Mitigation Act of 1989 requires IDNS to submit a report to the General
Assembly describing its findings and recommendations regarding the existence and nature of the
risk from radon in dwellings and other buildings in Illinois. This update is intended to serve that
purpose. The 1990 report contains new information on:
- Illinois residential screening project;
- Illinois legislation;
- IDNS sponsored training; and
- the State Indoor Radon Grant program
THE ILLINOIS RADON SCREENING PROGRAM
IDNS designed its radon program as a joint state/local effort wherever possible. To facilitate
this effort, training programs for local government personnel were held in areas where these
groups were interested, and radon monitoring was conducted as a joint study. IDNS completed
such training programs in the city ot Uiicago and in more than 80 counties throughout the state
usually involving local or regional public health or environmental health agencies or the Illinois
State University or the University ot Illinois Cooperative Extension Service.
The first phase of the program was screening Illinois residences using alpha track detectors
The detectors were deployed for no less than two weeks, but no greater than three months For
logistical purposes, the statewide screening was conducted on a county-by-county basis. The
number of detectors placed in eachcoumy was determined by using geographical and population
density considerations but limited Dyuie resources of the department. A minimum of 30 homes
were monitored in each county screenea with at least one home per township. In counties with city
populations representing a majority o the county, the city was allocated detectors for an additional
30 homes. Greater numbers of detec ors were allocated to the six northeastern counties, due to a
high population density. The number Placed was proportional to the county population.
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IDNS SCREENING PROTOCOL
Detectors were placed in the lowest livable area of the home whenever possible according to
EPA protocols (3). Houses with no livable basement were screened using first floor
measurements. Most of the measurements were taken during the heating season. Although
homeowners were not instructed to create artificial closed-house conditions, as they would during
a 2-day charcoal screening, it is assumed that most homeowners kept their doors and windows
closed during the heating seasons.
Homeowners participating in the screening were interviewed using a questionnaire that
included questions on the structural features of their homes and use of living areas and appliances.
The results of the interviews were compiled and related to the results of the screening
measurements. Screening measurement results were forwarded to the homeowners and to IDNS.
EPA recommends follow-up measurements for any house which has a screening result at or
above 4 pCi/L and a decision to mitigate be made on the basis of the follow-up measurement
results (4). The higher the exposure rate, the sooner mitigation should be performed. IDNS
recommended homeowners conduct annual follow-up measurements in any home which had a
screening result of 4 to 20 pCi/L. Annual measurements can be made by using alpha track
detectors for a year or can be made using a series of seasonal shorter measurements (4). For
homes which had a screening result greater than 20 pCi/L, follow-up measurements were offered
by the department to verify the screening result and to determine whether radon mitigation efforts
should be recommended.
To standardize this process, an averaged annual living area exposure of the residents was
calculated using the wintertime basement screening results and the ratio of spring living area to
basement follow-up measurements. Three annual living area exposures were calulated then
averaged for each home. The annual living area calculations were based on comparisons of 728
three-month measurements with year-long measurements made in the Reading Prong area and
seasonal data collected in Illinois homes (5). If the averaged annual living area exposure was
estimated to be greater than 8 pCi/L, then the homeowner was advised to take remedial action
without further delay. If this average was between 4 pCi/L and 8 pCi/L, then an additional
six-month measurement was recommended. Combined results of all measurements were then used
to determine whether mitigation was indicated.
SCREENING RESULTS AND DISCUSSION
As of September 1990, IDNS had performed screening measurements in 4,063 homes in 98
Illinois counties, as illustrated in Figure 1. These screening data are summarized in Table 1. The
indivual county radon averages are shown on Figure 2. The current data indicate 39 percent of
the basements tested have radon levels that exceed the EPA guideline of 4 pCi/L and 11 percent of
the first floor areas have such levels. In all, 1,263 homes sampled taken exceeded 4 pCi/L. This
is about 31 percent of the total.
The sample of houses screened to date is a small fraction (about 0.16 percent) of the 2.5
million privately owned houses in Illinois, but if this sample is representative, about 975,000 of
the houses in the state may have elevated basement levels and 275,000 houses may have elevated
first floor levels. Since this is a significant number of homes from both a public health and an
economic standpoint, and since there are yet no methods that reliably predict the radon
concentration in a given house, IDNS continues to recommend that all homeowners conduct radon
tests. The frequency distribution of the data is shown in Figure 3. The data suggest a log-normal
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distribution. This is consistent with Cohen's analysis of data taken nationwide (6).
RESULTS OF OTHER STUDIES
The EPA conducted a thirty four state joint EPA/state radon screening program (7). This
study indicated that from 0.4 to 70 percent of the houses in those states have the potential for
elevated radon levels, as compared to the current Illinois combined estimate of 31 percent. IDNS
plans to participate with the EPA in a joint screening during the 1990-91 heating season. The
results obtained during the EPA study cannot be compared directly to those obtained by IDNS
because the EPA studies are performed using charcoal canisters.
Earlier results compiled by a major supplier of alpha track detectors showed 30 percent of all
radon measurements across the country were above the 4 pCi/L level (8). These results are in
good agreement with the radon levels in Illinois homes. The average concentration of indoor radon
in this national study, 3.9 pCi/L, is approximately equal to the EPA guideline.
EFFECT OF HOUSE CONSTRUCTION CHARACTERISTICS ON INDOOR
RADON
A closer examination of the distribution of radon results by house construction characteristics
was done to develop a better understanding of the behavior of radon in various types of homes.
The following information was provided by homeowners and compiled in a database along with
the screening results:
- age of house;
- type of substructure (basement, slab or crawlspace);
- primary heating source (gas, oil, electric, others);
- basement characteristics such as cracks or drains; and
- crawlspace characteristics such as exposed earth.
Homeowners were also asked to rate their home subjectively according to its energy
efficiency on an arbitrary linear scale.
An attempt was made to compare these features and characteristics with either high or low
radon concentrations. Results are presented in Table 2.
The age of the house was not a good indicator. Homes less than 15 years old should be
more energy efficient than older homes but no increase in radon concentration was found in these
homes. On the other hand, homes greater than 50 years old are thought to be drafty but on the
average they were not lower in radon concentration. Unfortunately more than 86 percent of the
homeowners in the study rated their home energy efficiency as "good" or "excellent;" so little could
be drawn from this information, although the average level in these houses (4.0 pCi/L) was
slightly higher than those rated "not at all" or "somewhat" energy efficient (3.1 pCi/L).
Although successful radon mitigation efforts almost always depend on a well-sealed
basement floor, there was little evidence that houses with basement floor leaks and cracks
automatically have high radon concentrations. The presence of exposed earth either in a basement
or accessible crawlspace seemed to be a common factor in many of the higher concentration
homes. Homes with crawlspaces that are fully ventilated and not accessible from the basement
tended to be lower in radon than the average.
-------
Several studies have failed to show a correlation between certain home construction features
and high radon concentrations. A survey conducted by Cohen of 453 houses in 42 states found
only weak correlations between radon levels and home construction features (6). One of Cohen's
conclusions was that geological factors might control radon levels to a greater degree than
construction features. This poor correlation precluded public health officials from focusing efforts
on specific types of houses or ruling out radon problems for significant numbers of homeowners.
EFFECT OF GEOLOGICAL FACTORS ON INDOOR RADON
It is not clear whether there are any particular geological formations in Illinois which
contribute to high radon exposures. There is no evidence of any areas with radium concentrations
similar to those in the Reading Prong area, but radium levels do vary across the state and Illinois
soils do exhibit varying permeability and moisture content. Some investigators tried to link the
National Uranium Resource Evaluation (NURE) data with indoor radon levels, but the NURE data
is useful only for locating uranium and other nonspecific gamma ray anomalies.
Since IDNS did not have the resources to study geological factors directly on a statewide
basis, the original approach was to rely on the statewide screening program to identify clusters of
homes with elevated radon levels. This was to be done by screening neighborhoods around homes
with confirmed radon levels above 20 pCi/L. It was then planned to study the geology in these
local areas. Due to lack of resources, this neighborhood screening program was postponed. As
indicated in Table 1, the department identified about 44 neighborhoods that should be studied.
There are no known areas of the state which exhibit consistently elevated radon levels, such
as those found in Pennsylvania. The highest result recorded was 75.6 pCi/L in DeWitt County.
Although no other homes in that county were above 20 pCi/L, the average result for the county
was about 7 pCi/L. Other very high values were found in the state but they were due to the
disposal of radium wastes and not due to natural conditions.
Illinois screening data identified regions of the state that exhibit higher than average radon
concentrations. These regions are in north central and northwestern Illinois. IDNS identified 18
counties where the majority of the screening measurements were greater than 4 pCi/L (see Figure
4). The Chicago area was not identified as a problem area relative to the rest of the state, but there
may be small local areas of higher than average radon. IDNS has attempted to develop a simple
description of the geographical boundary of the area of greatest concern. This proved difficult.
Note, however, that the area with zip codes beginning with "61" are about twice as likely to have a
screening measurement in excess of 4 pCi/L than areas with zip codes beginning with "60" and
"62".
RADONINSCHOOLS
Not all personal radon exposure can be attributed to private residences. Studies are in
progress to determine what fraction of personal radon exposure is due to exposure at home. Some
factors that allow radon to enter houses also apply to commercial and public buildings. Some
public buildings are of particular concern due to potential radon exposure to children. Because of
this concern, IDNS initiated a screening program for schools. The program has had two phases
thus far. In the first phase, for each of 21 counties screened, two elementary schools were selected
for participation. Six detectors were placed in each school with at least two detectors placed on
each level. Detectors were placed only in areas frequented by students, such as classrooms,
-------
percent of the student areas contained radon levels exceeding 4 pCi/L.
Most recently, IDNS performed long term alpha track measurements in all public schools in
Clark and Wayne counties. A total of 25 schools were tested Only one student area had radon
levels in excess of 4 pCi/L. Data for all schools are listed in Table 3.
mwc has Keen involved in screening, follow-up and diagnostic measurements at a group of
Peoria^^ools since Febnaary imAt that time, IDNS placed 125 EPA choral detectors in six
schools for a three-day test. The results ranged from 0.5 to 19.6 pCi/L. Follow-up tests were
conducted by IDNS using alpha track detectors in 26 student areas that had screening results in
excess of 4 pCi/L.
In November 1989 the EPA Office of Research and Development (ORD) proposed a project
to perform diagnostic measurements in schools to develop effective mitigation strategies. EPA
Deiion V suggested a group of Peoria schools that were tested during tteFebruai? 1989 study be
considered for the ORD School Diagnostics and Mitigation Strategy Project. IDNS contacted
Peoria School District 150 administration, who agreed to participate. EPA and IDNS
representatives conducted a walk-through audit and made radon diagnostic measurements at the
Harrison, Tyng and Calvin Coolidge schools and determined these schools were suitable for the
ORD project.
In February 1990, the IDNS officially proposed to ORD that the Peoria schools should be
considered for the project. IDNS staff recommended the radon levels in one room of Harrison and
Tyng and three rooms in Calvin Coolidge be reduced to below 4 pCi/1 based upon their
three-season averages. In May 1990, the ORD team performed the diagnostic measurements in
Harrison, Tyng and Calvin Coolidge schools. The team reviewed the diagnostic data and
developed a report that recommends an optimum radon mitigation strategy for each school. The
report suggests the radon problems are caused to some degree by inoperable HVAC systems.
Schools are not yet required by either federal or state law to test for radon. However, IDNS
encourages all schools to conduct screenings for the same reasons home testing is recommended.
Some school districts voluntarily tested for radon, but many others are reluctant to do so for two
reasons. First, while radon screening costs may be relatively low, school officials do not believe
they have sufficient resources to mitigate radon problems if they are discovered. Secondly, since
there are no mandatory protocols for radon testing, school officials are concerned that tests
conducted now may not be valid once mandatory protocols are adopted. Even when voluntary
tests are conducted, school officials are reluctant to disclose results to IDNS. As a result, IDNS
has little information regarding the scope and results of voluntary testing.
RADON IN PUBLIC BUILDINGS AND IN THE WORKPLACE
Very little testing in public buildings and workplaces has been conducted. As with private
residences, commercial properties are being tested for radon when sold, but there is not a
significant effort on the part of employers to characterize employee workplaces. To our
knowledge, the Occupational Safety and Health Administration has not made radon exposure a
high priority compliance item. More research is needed to determine the nature and extent of radon
problems in commercial and industrial structures.
The Illinois Secretary of State (SOS) is the custodian of many of the state government
buildings in Springfield. IDNS and SOS conducted a screening study of 26 buildings in
Springfield in 1989. The results ranged from 0.3 to 15.2 pCi/L. As a result of this screening,
-------
IDNS recommended follow-up measurements be made at three locations. SOS took follow-up
steps at all three locations. The most interesting mitigation was conducted in the basement of the
state capitol. Grab samples in the electrical shop of the capitol ranged from 13.4 to 21.7 pCi/L.
The capitol is a complex structure with underground passageways and ventilation plenums exposed
to soil. Very little fresh air was being routed to the shop area. In this case, changes in the HVAC
system were needed to solve the radon problem in the shop and bring radon concentration down
below 4 pCi/L.
REDUCING RADON EXPOSURE
The objective of the statewide radon program is not only to identify any problems related to
radon exposure, but to provide recommendations for remedial action to reduce radon exposure.
Most IDNS follow-up studies in houses with elevated radon levels involve evaluating causes, as
well as confirming screening measurements. Radon is not only a significant public health issue,
but also an economic issue. If 31 percent of Illinois residences ultimately prove to have levels
greater than 4 pCi/L, this translates to about one million homes. The cost of reducing radon levels
could range from $200 to $2,000 or more per home, meaning a potential cost of $200 million to $2
billion to Illinois citizens. These cost estimates apply only to private residences and do not include
public or commercial buildings.
IDNS EXPERIENCE IN RADON MITIGATION EFFORTS
In 1988 IDNS staff completed a remediation project at a home in Schaumburg. At the
request of the village of Schaumburg, IDNS provided technical assistance including evaluation of
the radon levels; diagnosis of the source; and routes of entry and recommendations on a reduction
method. Grab sample measurements indicated that a basement sump and the heating ductwork
beneath the slab-on-grade portion of the house which penetrated the adjacent basement wall were
the major entry routes. Sealing the sump hole and other minor radon entry routes was not effective
in reducing the basement radon levels to below 4 pCi/L. A drain tile ventilation system using the
existing drain tile loop and sump hole was then installed. This active system reduced the radon
levels to about 2 pCi/L. Details of this mitigation effort are reported elsewhere (9).
At the request of the Illinois Department of Energy and Natural Resources (ENR), IDNS
monitored radon levels and assisted in a remedial action project at the Springfield Energy House.
This house was designed and built by ENR to demonstrate the value of energy efficient building
techniques and features. The features include a super-insulated shell to reduce heat loss and an
underground ice storage cooling system to provide air conditioning in the summer (10). Since it is
suspected that homes with low air exchange rates have high radon levels, the house was screened
and found to have high concentrations in localized areas. The main route of entry for radon was
the penetration from the basement to the ice storage unit. Once this penetration was sealed, an
annual follow-up measurement was made. The average general living area concentration was
found to be 3.8 pCi/L.
IDNS is concerned about the availability and reliability of radon mitigation contractors.
Currently there is no requirement for radon mitigation contractors to register with the state, nor is
there a mandatory certification program run by the federal government. IDNS recommends that
homeowners employ contractors who have successfully completed the EPA Radon Contractor
Proficiency Program. This program is available to Illinois contractors through the Midwest
Universities Radon Consortium (MURC). Some radon mitigation work is currently being done by
contractors with previous experience in home renovation ana remodeling, but whose education and
-------
experience in radon detection and mitigation techniques are not known.
PUBLIC EDUCATION PROGRAMS
A maior objective of the Illinois program has been to inform and educate the public about
, A Tcnnrtnfthis oroeram IDNS provides basic information about indoor radon and its
radon. As part. of this fnformation about radon monitoring. A total of 30
oresenta^ions were given bftween January 1989, and July 1990, on general radon awareness.
Another 30 presentations were given in conjunction with the statewide residential radon screening
^dv Thes?oresentations were designed to train local volunteers to place radon detectors in
accordant with IDNS protocols and to complete the documentation needed for-the^study. Because
?heSts oTthe statewide monitoring program cannot be used to predict radon levels in specific
Scupants to monitor their own houses and to report high results to
IDNS.
In order
Cctbnal materials have been distributed to the ".OOOcopies 0f the
"Citizens Guide to Radon" (1986 edition) prepared by the EPA and reprinted by IDNS.
Information about radon mitigation contractors has been only a/aia^^d°"g^®
EPA radon lEer^re lteuteTmNS has
SvrfcwSnromplaintfagainst contractors, but the department does not have any regulatoiy
o^ ^SSon cmtrUrs. Both specific regulator authority and the resources to
s^n™r training to contractors would provide significant consumer protection and increase public
confidence in the program.
From July 1986, to February 1988, the department funded and staffed a toll-free.radon
information hotline" lo provide ^formation on radon to
average of 500 calls per month were received. Funding and staffing were suspended
program in 1988 but resumed in August 1990.
In March 1987, the department sponsored a conference on radon, radium and environmental
radioactivUy One full da? was devoted to talks on radon in homes, radon risk evaluation,
^Mloeic^ considerations monitoring procedures and midgatton techniques. The conference was
SgStoDliScid^ns, public health agencies and environmental groups, and was attended
by about 500 people.
County and other local government agencies have expressed interest in assisting with public
education, but have limited resources to conduct large scale programs. IDNS supplies these
agencies with speakers, technical advice and printed information for distribution by their offices.
ILLINOIS LEGISLATION
Two key pieces of radon-related legislation were passed during 1989. The Radon Mitigation
Act authorizes the IDNS to establish and coordinate a comprehensive program for detecting and
reducing the amount of radon in homes and other buildings in Illinois. The act exempts radon
results obtained by IDNS from disclosure requirements of the Freedom of Information Act. This
is an important step forward allowing IDNS staff to continue radon studies while protecting the
-------
participants' property values. The bill also enabled IDNS to secure independent general revenue
funding from the Illinois General Assembly for radon related projects.
House Bill 1611, "An Act in Relation to Radon Testing", authorizes IDNS to establish a
registration program for persons selling any device or performing any service for compensation to
detect radon or its decay products. The program is intended to regulate those who place passive
detectors in structures or who perform measurements using working level monitors, grab samplers
and other active methods. Rules for implementation of this program (32 Illinois Administrative
Code 420) were published in the Illinois Register on November 30, 1990. IDNS estimates there
will be 300 registrants in this program.
IDNS SPONSORED TRAINING
In anticipation of the implementation of these rules, IDNS and the MURC co-sponsored three
training sessions on radon measurements for potential registrants. The sessions were held in Mt.
Vernon, Bloomington and Des Plaines during the week of April 9, 1990. A total of 110 people
attended, but the sessions were overbooked by a considerable margin. IDNS plans to repeat the
sessions as soon as the rules are final.
EPA GRANT
On May 1,1990, IDNS was awarded a grant under the State Indoor Radon Grants program
administered by the EPA. Under the provisions of the grant, IDNS will undertake a greater
number of projects than it would using only state funding. Some of these projects include
participating in the EPA/state screening program; providing a limited number of free radon
detectors to low income school districts identified by the state Board of Education; coordinating a
school mitigation demonstration project; conducting a follow-up study in neighborhoods identified
as potentially exhibiting elevated levels of radon and conducting a study of Illinois building codes
as they relate to radon resistant new construction.
CONCLUSIONS
1. IDNS has performed radon screening measurements in approximately 4,100 homes in 98
counties. Results indicate about about 31 percent of all homes tested have radon levels greater
than the EPA standard of 4 picocuries pa* liter. The screening program identified certain areas in
Illinois with significant percentages of homes with screening results in excess of the standard that
merit additional study.
2. Schools are not yet required to conduct radon testing. IDNS has little information regarding
the scope and results of voluntary testing, but is concerned that the uncertainties regarding costs
of mitigation and testing are forcing school officials to postpone testing until it is mandatory.
3. IDNS is providing a wide variety of educational information in response to public inquiries.
This effort is, for the most part, a reactive effort and therefore limited in scope. Although radon
has received considerable publicity, most members of the public still need basic information
about radon. News reports and public service announcements provided by the media have been
-------
either misleading or ineffective.
4. The registration and training of persons performing radon measurement services are good
initial steps toward assuring consumer confidence in radon services in Illinois. Radon mitigation
services are still not covered under the program.
5. Radon reduction in homes is still primarily a post-construction activity in Illinois. There is no
significant effort on the part of builders or architects to incorporate radon resistant features in
new construction.
6. Radon measurements made for the purpose of satisfying provisions of a real estate contracts
are not being conducted according to any specific protocols or quality assurance guidelines. This
causes considerable difficulty for homeowners whose transactions depend on accurate results.
Erroneous results may cause delays in the transaction, or may force a homeowner to install costly
mitigation equipment where it is not needed.
RECOMMENDATIONS
1. Complete the radon screening of all Illinois counties. Four counties remain to be screened
before the project is considered complete.
2. Conduct follow-up studies in neighborhoods where local clusters of homes with potential
radon problems are suspected. This would help to identify localized areas where the geological
conditions could be studied.
3. Encourage and support voluntary testing by schools. This could be done by conducting
briefings for school administrators, conducting mitigation demonstration projects and by
providing free detectors to a limited number of low-income school districts.
4. Continue to develop more active approaches to public education. This might include providing
radon information to large numbers of schools and libraries. More effort is needed to educate
the media as well. IDNS staff should continue to respond by sending radon information to
members of the media and by making department representatives available for interviews.
5. Develop and implement a certification program for persons or companies who perform radon
mitigation services. Although EPA conducts a voluntary program, Illinois has no mechanism
for formally recognizing participation in the program. In conjunction, IDNS should continue
to develop and conduct training programs for those who offer mitigation services as well as
measurement services.
6. Evaluate the need for changes in building codes in Illinois, since the construction of radon
resistant structures is the only long term solution to the indoor radon problem. Illinois should
follow the lead of states in the eastern U.S. that have adopted radon resistant features in
building codes.
7. Work with the EPA and with the Illinois Association of Realtors to arrive at a consensus
regarding protocols and quality assurance associated with radon measurements made for real
estate transactions.
-------
The work described in this paper was not
funded by the U.S. Environmental Protection
Agency and therefore the contents do not
necessarily reflect the views of the Agency
and no official endorsement should be
inferred.
ACKNOWLEDGEMENTS
For their assistance in providing the field staff for the Illinois radon screening program the
authors thank the Illinois State University, the University of Illinois Extension Service and local
county health departments.
REFERENCES
1. Illinois Department of Nuclear Safety, Radon in Illinois: A Report to Governor James R.
Thompson from the Governor's Task Force. 1986.
2. Illinois Department of Nuclear Safety, Radon in Illinois: A Status Report. IDNS Internal
Report, 1988.
3. U.S. Environmental Protection Agency, Office of Air and Radiation, A Citizen's Guide to Radon:
What It Is and What to Do About It. Draft, March 1986.
4. Ronca-Battista, M., Magno, P., Nyberg, P., Applications of Radon and Radon Decay Product
Measurement Protocols For Screening and Confirmatory Purposes. U. S. Environmental
Protection Agency, Office of Radiation Programs, Draft, March 1986.
5. Granlund, C. and Kaufman, M., "Comparison of Three Month Screening Measurements with
Year Long Measurements Using Track Etch Detectors in the Reading Prong," Pennsylvania
Department of Environmental Resources, Bureau of Radiation Protection, 1988.
6. Cohen, B. L., "A National Survey of 222Rn in U.S. Homes and Correlating Factors," Health
Physics Vol. 51, Number 2,1986.
7. U.S. Environmental Protection Agency, Office of Radiation Programs, Notice to IDNS,
September 1990.
8. Terradex Corporation, Personal Communication, 1988.
9. Hamel, M. A., "Radon Mitigation in a Schaumburg, Illinois House: A Case History," IDNS
Internal Report, 1988.
10. Illinois Department of Energy and Natural Resources, "The ENR Springfield Energy Home",
"The Springfield Energy Home: 2544 Greenbriar," 1987.
-------
o
{/) 1989-90
o
Jo Daviess
ebaqo
Mc Henry
Stephenso
Boon
Lake
Carroll
Ka ne
/ wy ic s / >
yyy////
Whit
Du Page
Cook
Kendall
Will
Rock Islan
Henry
La Salle
Grundy
nam
' Ma rshal
Kankake
/Stark-'
Knox
Livingston
Warren
Henderson/L . , /
*2?
/Peoria A Woodford
t ord
Tazewel1
Mcdonough'"
Mc Lean
Hancock
Mason
Champaign
'"Vermilion
Schuyle
Brown Cass
De Witt
Logan
Menard
Adams
Piatt
aeon
Sangamon
Douglas
organ
Edgar
Scot t
Pike
Christian
Coles
Clark
Macoupin
/Shelby
Greene
v/////s.
Montgomery
Cumberlan
Calhoun
Jersey/
Ef fingham
Fayette |
lord
mm
Bond
Madi son
~Lawrence
tJcilnt
Wabash
St. Clair
Washington^
Jet fersorv
Edwards
Monroe
Hamilton White
Perry
/
franklin
Randolph
Y77XS//A
Jacksorws X/S/
Gallatin
Saline
Wi 11iamson
XSY//
Pope I Hardin
Union
Johnson
Alexander
Pulaski-
Massac
1986-88
Fall 1990
Figure 1. Illinois Radon Screening Status September 1990
-------
Jo Daviess
Mc Henry
StephensonWinnebago
Lake
Boon'
Ogle
Carroll
Kane
Du Page
De Kalb
Wh i t esi de
Lee
Cook
Kendall
Rock Island
Bureau
Wi 11
Henry
La Salle
Grundy
NA
.Putnam
Kankakee
Stark
Marshal1
Knox
Li vi ngston
Warren
Henderson
Woodford
Iroquoi
Peoria
Fulton
Mc Lean
Ford
Ha ncock
NA
Mcdonough
Mason
Schuyler
Vermilion
Champaign
De Witt
Logan
Menard
Brown
Adams
Piatt
Macon
Morgan
Dougla
NA
Sangamo
Edgar
Scott,
.Moultrie.
Pike
Coles
Chri stlan
1 Greene
3.8
Jersey
Clark
Macoupin
Shelby
Cumberland
Montgomery
Ca1houn
Effinghan Jasper
Crawford
Fayette
Bond
Madi son
Clay Richland
Lawrenc*
Clinton
NA
Marion
Wabash
Wayne
Washington Jefferson
Edwards
Monroe
| White
'Hamilton 2.0
Perry
Randolph
Franklir.
Gallatin
I Saline
Williamson 1.9
Jackson
I Pope I Hard in*
Union
Johnson
Alexander,
Pulaski.Massa<
Figure 2. Average Radon Concentration (pCi/L) by County
-------
900.
8 00.
7 00
600-
500
•p
c
3
O
O
4 00
300-
200-
100.
~ In(x) of pCi/L
-3 -2
Figure 3
l « l
Geometric Mean =2.6 pCi/L
-10 12 3 4
Frequency Distribution of Radon Results
-------
V ™W///A
Jo Daviessi;# 'Stephenson;
773
Boone
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- Lake- •
li
O
Kane
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Du Page
Cook
m
Kendall
X///L
Rock
Will
Bureau-
-V.Putnam ftjiS
a-La Sal las
Henry
Grundy
-•Kankakee
Marshall
Knox
peo?ill
Woodfor
m
Henderson
/.'Iroquois.*/,
Ford
c Lea
.-Fulton..-
Tazewell
McDonoughi
li
Hancock
Mason
Vermilion
////////. Piatt/
Schuyler
Champaign:
¦-Adams
Menard:
B r ow n-Ca s s
¦//Ma co n.vJ//////
WsM
Sangamon
Dougla
Morga
Edga r
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Christian
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Cumberland.*
[li' " " ir
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Montgomery
Calhoun
Effingham
.".Jersey.
3
Crawford
Jasper..
Bond
"Madison
:*:*—J , • Lawrence
Richland ^
Marion-
Clinton
///¦¦//¦^¦^rt^!!^^
/ //////// / /¦{///•j/-Wabash
"wayne*• •'Edwards • •
Washington--Jefferson
Monroe:
Hamiltorf/White^
.Randolph.
...Perry.
Franklin
Saline
//Ja ck sonVf. - ///. - /.
Williamson
Gallatin
Hardi
UnionSJohnson.
Alexander*
....puiask
nassacv:;!
Less than 25% over 4 pCi/L
25% to 50% over 4 pCi/L
Greater than 50% over 4 pCi/L
Not Screened
Figure 4. Illinois Screening Program December 1990
-------
Table 1
SUMMARY OF ILLINOIS RADON SCREENING RESULTS BY LIVING AREA
Min
Avg
Max
#>4
%>4
#>20
%>20
Living Area Number
Result
Result
Result
pCi/L
pCi/L
PCi/L
pCi/L
Basement
2920
0.1
4.6
75.6
1132
39
43
1
First Floor Bedroom
650
0.3
2.3
19.3
81
12
0
0
First Floor Living Area
467
0.1
2.1
23.2
47
10
1
0
Other
26
0.6
2.3
12.2
3
12
0
0
Total 4063 0.1 3.9 75.6 1263 31 44 1
-------
Table 2
COMPARISON BETWEEN RADON CONCENTRATIONS AND
BUILDING CHARACTERISTICS
Ape of House
Number
Averaee fpCi/L)
Less than 15 years old
919
3.9
Greater than 50 years old
1388
4.1
Substructure Tvpe
Number
Averaee CpCi/L)
10()% Basement
1760
4.1
100% Slab
164
3.4
100% Crawl space
535
2.0
Basement and Slab
223
5.1
Basement and Crawl Space
880
4.6
Subjective Energy Efficiency
Number
Averaee CpCi/L)
Not at all
184
3.2
Somewhat
37
2.5
Adequate
333
3.6
Good
1302
3.9
Excellent
2272
4.0
Basement Characteristics
Number
Average fpCi/L)
Exposed Earth
239
5.3
Sump(s)
885
4.5
Crack(s)
784
4.6
Drain(s)
1660
4.6
None of the above
50
3.5
All of the above
39
5.6
Crawlspace Characteristics
Number
Averaee (pCi/L)
Crawlspace Entry & Exposed Earth
480
4.7
Crawlspace Vented
504
3.1
Primary Heating Source
Number
Averaee (pCi/L")
Solar
5
7.5
Oil
174
4.8
Electric
421
3.8
Natural Gas
2689
4.0
Propane
448
3.8
Wood
174
3.0
Coal
6
1.5
Other Factors
Number
Averaee fpCi/L)
Central Air Conditioning
1367
4.2
-------
County
Calhoun
Champaign
Clark
DeWitt
Effingham
Ford
Gallatin
Henry
LaSalle
Livingston
McLean
Monroe
Montgomery
Moultrie
Pike
Table 3
SCHOOL RADON SCREENING RESULTS
pCi/L
2nd Floor
3rd Floor
Basement 1 st Floor
n Range n Range n Range n Range
3 2.1-3.8 13 1.1-3.3 2 0.5M.9 0
2 3.2-4.5 3 1.7-4.2 3 1.4-3.7 2 0.8M.2
0
0
0
1
0
0
0
0
0
2.3
204 0.1 *-4.3 0
2 3.4-3.9 6 1.4-3.2 2 2.0-2.8 0
4 0.8*-1.2 4 0.8M.2 0
1 4.6 7 1.5*-2.9 2 0.8*-1.4 2 0.7*-2.4
1.3-2.1 2 1.4-1.7 2 1.4-1.5
8 1.2*-10.0 2 0.8*-2.2 2 1.1-1.5
10 0.8*-2.2 1 0.8*
0
0.7*-1.5 2 1.9-3.8 2 0.7*-0.7*
5 4.3-9.2 5 3.3-8.0 2 3.2-5.0
0.9-3.0 6 1.0-2.7 0
8 1.6-3.2 2 1.7-1.8 2 1.0-1.5
2.3-4.5 2 1.0-1.2 2 1.7-1.8
2 2.3-6.0 15 0.2*-5.8 1 1.3
-------
Table 3 (cont'd)
County
Saline
Sangamon
Schuyler
St. Clair
SCHOOL RADON SCREENING RESULTS
pCi/L
Basement 1 st Floor 2nd Floor 3rd Floor
n Range n Range n Range n Range
3 1.5-4.4 3 0.7-1.6 3 0.7M.4 0
1 25.8 1 1.9
0
0
1 3.1
8 1.1-6.3 2 1.1-2.2 2 1.5-1.7
1.6-3.1 0
Wayne
White
Will
36 0.1 *-1.4 241 0.1 *-3.6 0
0
0
0
0.7-1.6 4 0.7-2.2 0
8 0.9*-2.3 2 0.5*-0.9* 2 1.4-1.4
Woodford
0
0.8*-5.6 4 1.0-3.4
1.2-2.7
* Less Than Minimum Detectable Concentration
n = Number of rooms measured.
-------
Session VIII:
Radon Prevention in New Construction
-------
VIII-1
TITLE: Long Term Monitoring of the Effect of Soil and Construction Type
on Radon Mitigation Systems in New Houses
AUTHOR: D.B. Harris, EPA - Office of Research and Development
This paper was not received in time to be included in the
preprints so only the abstract has been included. Please check
your registration packet for a complete copy Qf the paper.
ABSTRACT The influence of 3 soil conditions and 3 neu home
construction types on the performance of radon mitigation systems
has been monitored for more than 6 months. Data collected in 2
homes of each combination included soil radon sub-slab and in the
surrounding yard, slab movement and indoor radon. 2 unmitigated
homes were used as controls. A master home uas monitored uith
continuous instrumentation including radon, differential
pressures and temperatures as uell as weather data. Initial
anaysis shows a strong increase of indoor radon with
precipitation events or frontal passage. Significant slab
movement has been seen in three houses with the polyurethane
f1oor-to-wal1 seal rupturing in two and severe cracking in one
necessitating replacement of the entire slab. Further analyses of
these data are presented.
-------
A COMPARISON OF INDOOR RADON CONCENTRATIONS BETWEEN
PRECONSTRUCTION AND POST-CONSTRUCTION MITIGATED
SINGLE FAMILY DWELLINGS
by: James F. Burkhart, Physics Department,
University of Colorado at Colorado Springs
Colorado Springs, CO 80933
Douglas L. Kladder, Residential Service
Network, Inc.,
525 E. Fountain
Colorado Springs, CO 80903
ABSTRACT
We have done a detailed study comparing indoor radon
concentrations among single family dwellings in Colorado Springs
that were mitigated prior to the completion of construction and
similar buildings that were mitigated after construction. There
appears to be evidence which indicates that "preconstruction"
mitigation is more effective at lowering indoor radon
concentrations than "post-construction" mitigation.
A total of 102 owners of single family dwellings, in two
different areas within the city, agreed to participate in the
study. Thirty-nine homes formed the preconstruction mitigation
category (with 14 of these homes having only passive systems), 24
had been mitigated after construction and the final 39, chosen as
a control group, had never been mitigated but shared similar soil
and surficial geological features with the mitigated homes
(including distance to nearby faults). Eighty nine homeowners
successfully completed the test. All of theses houses were
tested over the same 48-hour period, under closed-house
conditions, thereby controlling the variables of weather and, to
some extent, occupants' usage.
By analyzing the data obtained, we can conclude that there is
a statistically significant difference in post-mitigation indoor
radon concentrations (as measured by simultaneous charcoal
screening tests) between the preconstruction and the
post-construction mitigated homes. The preconstruction category
exhibited the lower radon average, although both mitigation
categories had averages below 4.0 pCi/L. Such a conclusion could
have an impact on current mitigation practices, especially as
they pertain to new housing construction.
Esthetics, installation costs and operating costs of the two
mitigation techniques (pre and post-construction) are also
discussed herein.
-------
INTRODUCTION
* Study is to assess the relative
The purpose of this * duction methods in residential
effectiveness of £ado^ utilized after the home is constructed
structures when they , me is mitigated prior to the completion
as opposed to when tne d that the results discussed herein
of construction. I for the building industry and those
will provide informa developing approaches to mitigating
agencies which assist it
new and existing homes.
^r.o-ived by the authors when it was noted that
This study was co .__mitigation testing over the last three
data collected from p . ndj_cation that post-construction
years were giving , . lar results to mitigations performed
mitigation provided s ^ construction. However, such a
prior to the completi ^ make due tQ varying environmental
conclusion was dir i . test results. Consequently, this study
conditions which a many of the typical testing variables by
was designed to remov simultaneously and on the same floor,
testing all subjec hypothesis that active mitigation,
As will be seen a 5 or after construction, had essentially
whether performed . t be in correct, based upon the total data
the same results provea ^
obtained.
jnr1-ed concurrently within two different
The study wa® cq inaS, Colorado, which we refer to as Area 1
areas of Colorado p dy areas offer a unique opportunity for
and Area 2. The t both infill subdivisions where a
comparison sin e y s have no radon mitigation system at
significant number of ^m®nmitigated homes serve as a basis for
?eferencegasYto what a mitigated home might have been if no radon
reference as to wna been used. Furthermore, these same
reduction tec niqu large number of homes that had been
areas had a relati y tems (i.e.; operating fans installed)
mitigated with act egory 2) and prior to the completion of
after construction (Categ y category w&s neCessary to
distSishnbitween these homes mitigated during construction
aistlnguisn Detween >- homes using only caulking, membranes or
using active systems « Y these latter
p aS - designated
these radon ready houses
_ . . j_-tion was voluntary and solicited on a
Homeowner par i through the two appropriate homeowner's
neighborho ^v-.pfore no preselection of mitigation techniques
Hiwev"^^sequent interviews with participants
occurred. „n ' mitigated homes with active systems
indicated th empl°yec* sub-slab or sub-membrane
(Categories 2 and 3) as the
primary mitigation method. No
depressuriza ion determine relative ventilation rates
attempt has been made to
within test homes.
.. tore all within a half mile radius while homes
Homes in Area 1 were
-------
in Area 2 were within a one-quarter mile radius. The homes in
both areas were custom homes, ranging in size from 3,000 to 4,000
square feet of livable area. Most homes had finished walk-out
basements.
The number of homes initially participating in this study fell into
the four categories as noted in Table 1 below. The numbers in the
brackets, on this same chart, show the number of participants who
conducted the charcoal canister test correctly and who were
subsequently used as our data base.
TABLE 1. NUMBER OF HOMES PARTICIPATING IN THE STUDY
Category
Area 1 Area 2
Total
1 Homes never mitigated 26 (22) 13 (13) 39 (35)
2 Homes mitigated after construction 12 (12) 12 (11) 24 (23)
3 Homes mitigated during construction 19 (15) 6(4) 25 (19)
4 Homes made "radon-ready" for future 10 ( 8) 4(4) 14 (12)
mitigation
GEOLOGY OF THE TEST AREAS
A previous study (1) had already shown correlations between
certain characteristics of the soils and geology of these two
areas and the indoor radon concentrations as measured by
screening tests. Specifically, elevated radon concentrations are
predicted for these two areas because of low shrink-swell
potential (indicating very little clays) and relatively high
permeability of the soil as determined from the Soil Conservation
Service County Soil Surveys (2). The surficial geology of both
areas is made up of rock derived from the Pikes Peak batholith
(3) which is known to contain 5.0 ppm of uranium (4). Finally,
Area 2 is known to be relatively close to a major fault system.
This fact is believed to contribute to enhanced radon transport.
A more precise breakdown of the above characteristics for each
of the two areas is as follows:
Area 1 soil has a low shrink-swell potential with a
permeability of 2 to 6 inches of water per hour. The surficial
geology is a Dawson Arkose with some Verdos alluvium (both
dervived from the Pikes Peak granite). The average distance of
these homes to a major fault is 2.8 km.
-------
Area 2 soil has a low shrink-swell potential, also, with a
permeability of 6 to 20 inches of water per hour. The surficial
geology is Rocky Flats alluvium (which is also derived from the
Pikes Peak granite). The average distance of these houses from a
major fault is .75 km.
Ignoring house construction details completely, the above
characteristics would lead one to predict elevated radon in homes
in both areas and the higher permeability and closer distance to
a fault in Area 2 would suggest even higher radon levels in those
homes. These predictions will be seen to be verified when the
actual measurements are discussed in the Statistics section,
below.
TESTING METHODOLOGY
Radon Measurements Laboratory, housed at the University of
Colorado-Colorado Springs, is a primary lab for the evaluation of
radon concentrations using the 48 hour, four-inch, open faced
charcoal canister. These canisters are of typical design with
approximately 70 grams of 8 X 16 mesh Calgon charcoal encased in
a four-inch diameter canister, one-and-five-sixteenths inches
high, covered with a 30-50 % open-mesh retainer screen. The
laboratory has analyzed over 8,000 canisters over the last three
years.
Canisters are read using a three inch by three inch Nal(Tl)
crystal housed within a commercial lead shield. A 1,024 channel
MCA is used to look at the three most intense lead-214 and one
bismuth-214 photopeak lying between 220 and 692 KeV. The minimum
detectable activity (MDA) at the 3 G level was calculated to be
0.13 pCi/1 for canisters measured 3 hours after closing and
slightly higher for the balance of the canisters.
The usual quality assurance procedures were in place during
this testing period with 100 % of the blanks being identified and
duplicates above 4.0 pCi/1 all within the 10 % precision
expected. The 2 a error was 0.17 pCi/1 at 1.0 pCi/1 and 0.4 pCi/1
at 30 pCi/1. This low error was maintained by measuring all the
canisters (after equilibrating) the same day the test concluded.
The canisters were delivered to the participants by the
authors along with a detailed instruction sheet. The instruction
sheet augmented prior phone conversations and further oral
instructions at the time the canisters were delivered. The tests
were all to begin on the morning of December 17th and conclude on
the morning of December 19th, 1990. The canisters were placed in
an open area in the basement (ih most cases, the family room), 30
inches off of the floor in the center of the room. The canisters
were sealed by the homeowner and placed outside for pick—up by
-------
the authors. Non-compliance with the instructions, or failure to
perform the test, led to 13 of the original 102 participants
being dropped from the subsequent data base. This gave us an 87 %
compliance with the fairly stringent test requirements.
THE WEATHER DURING THE TESTING PERIOD
Since all of the homes were tested during the same time period
and the distance between the two test areas is only a few
kilometers, the weather was identical for all houses. It is
probably safe to assume, therefore, that pressure differentials
brought on by outside temperatures, wind, surface conditions
(i.e.; frozen soils) and atmospheric disturbances were also
similar.
Nonetheless, it is instructive to review the climatological
data for that 48 hour period because the weather conditions were
clearly such as to promote an honest screening test by
discouraging surreptitious ventilation. Table 2 below shows the
weather data from the morning of December 17th through the
morning of December 19th. Not shown on this table is the fact
that the winds were gusty for a short time on the morning of the
18th, with a peak gust of 48 mph from the northwest.
TABLE 2. CLIMATALOGICAL DATA FOR THE TEST PERIOD
Date temp
(high and
low)
pressure
winds
precipitation
Dec 17
30°F
17°F
29.78 i
8.2mph
light snow
Dec 18
4 9°F
17°F
29.62
10.8mph
none
Dec 19
27°F
21°F
29.60 ->
8.Omph
light snow
STATISTICS
This section is in two parts. First, the raw data will be presented
in histogram form for each area separately and then both areas
combined. Second, the results of the t-tests (testing the means of
two populations to see if the populations are the same or different)
will be given after each histogram.
RAW DATA IN HISTOGRAM FORM
Figure 1 below compares the indoor radon concentrations as measured
-------
during the testing period in Area 1 with the number of houses havin
a particular radon concentration. The black bars refer to those
houses which were never mitigated (Category 1) and the bars with hash
marks within them refer to houses which have passive systems oni,
(Category 4), the so-called "radon ready" homes. *
,
| Area 1-Categories 1 and 4
113 Category 4 ¦ Category 1
2 4 6 9 1012141618
pCi/I
Figure 1. Radon in homes in Area 1, Categories 1 and 4
Area 1-Categories 2 and 3
category 2
category 3
L
0 25 0.75 1.25 1.75 2.25 2.75 3.25 3.75 4.25 4.75
pCi/I
Figure 2. Radon in homes in Area 1, Categories 2 and 3
-------
Figure 2 above makes the same comparison between number of houses
and radon concentrations in Area 1 only using houses mitigated after
construction (Category 2) and houses mitigated during construction
(Category 3).
Comparing Category 1 and Category 4, in Area 1, and using the null
hypothesis that the two categories represented the same population, a
t-test was performed. The t-test, with a t value of .017, tells us
that the two categories are indistinguishable. It would appear that
"radon ready" houses have the same radon as unmitigated houses. The
statistics are given in Table 3.
Comparing Category 2 and Category 3, in Area 1, and using the null
hypothesis that the two categories represented the same population, a
single tailed t-test, with a t value of 2.416 indicates that the two
populations are indeed different at the 95% confidence level with the
houses mitigated during construction (category 3) having the lower
radon mean. The statistics are summarized in Table 3
Figure 3 below compares the indoor radon concentrations as measured
during the testing period in Area 2 with the number of houses having
a particular radon concentration. The black bars refer to those
houses which were never mitigated (Category 1) while the bars with
hash marks within them refer to houses which have passive systems
only (Category 4).
Area 2-Categories 1 and 4
category 1
category 4
6 8 10 12 14 16 18 2022242628
pCi/l
Figure 3. Radon in homes in Area 2, Categories 1 and 4
-------
Figure 4 compares the indoor radon concentrations in Area 2 with
the number of homes at a particular radon concentration. Here, the
black bars refer to homes mitigated after construction (Category 2)
while the hash mark bars refer to homes mitigated during construction
(category 3).
Area 2-Categories 2 and 3
¦ Category 2
H Category 3
9.25 0.751.251.75 2.25 2.75 3.25 3.75 4.25
pCl/l
Figure 4. Radon in homes in Area 2, Categories 2 and 3
Comparing Category 1 and Category 4, in Area 2, and using the null
hypothesis that the two categories represented the same population, a
one-tail t-distribution, with a t value of 1.304, seems to confirm
the null hypothesis. That is, as in Area 1, "radon ready" homes have
the same average radon as do unmitigated homes. The statistics are
shown later in Table 4.
Comparing Category 2 and Category 3, in Area 2, and using the null
hypothesis that the two categories represented the same population, a
one-tail t-test, with a t value of .091, seems to confirm the null
hypothesis. That is, homes mitigated during construction have the
same average radon as do homes mitigated after construction. It
should-be mentioned that the small number of homes (only 4) in
category 3 make this conclusion far from certain, although
statistically justified. The statistics are shown later in Table 4.
Finally^ the data from the two areas is combined, thereby making
any conclusions more general and, because of the larger numbers
involved, more convincing. We begin by showing a histogram of the
combined data, Categories 1 and 4 in figure 5.
-------
6-
C/5
Ui
X
LL.
O
CC
Ui 2
CQ
2
Combined Data-Categories 1 and 4
¦ Category 1 (Unmitigated)
M Category 4 (Radon Ready)
4
I
ll 1
I I
yy\ ft.
2 4 6 9 1012141618202224262 8
pCi/l
Figure 5. Radon in all the homes combined, Categories 1 and 4
When we combine all the data from both areas, we can also compare
radon levels in homes which were mitigated during construction
(Category 3) and homes mitigated after construction (Category 2) .
This comparison is given below in figure 6.
CO
LU
3
o
Z
LL
O
CC
UI
GQ
2
3
12
io H
8
6
41
2
0 4
Combined Data-Categories 2 and 3
Category 2 (Existing Houses)
Category 3 (New Construction)
L
0.25 0.75 1.25 1.75 2.25 2.75 3.25 3.75 4.25 4.75
pCi/l
Figure 6. Radon in all the homes combined, Categories 2 and 3
-------
Comparing unmitigated homes (Category 1) with "radon ready" homes
(Category 4) in the combined data, and using the null hypothesis that
the two categories really represent the same population, a single
tailed t-test with a t value of .987 seems to confirm the null
hypothesis. At this point, it seems safe to say that "radon ready"
homes are no better at reducing radon concentrations than are
unmitigated homes. The statistics are shown in Table 5.
A last comparison is now made. This is comparing houses mitigated
during construction (Category 3) with houses mitigated after
construction (Category 2) with all data combined. Again, the null
hypothesis is that the two categories will represent populations with
similar averages and standard deviations, i.e.; that it makes no
difference in indoor radon levels if a house is mitigated during or
after construction. This time, it is probably safe to reject the null
hypothesis because a single tailed t-test indicates that the two are
separate populations at the 98% confidence level, with a t value of
2.059. The statistics are shown in Table 5.
To show the effectiveness of the radon prevention measures in the
three mitigation categories, a final histogram is presented. Figure 7
compares the average of each of the categories when all of the data
is combined.
Combined Data Averages
Categories
Figure 7. Average radon in a11 homes combined, broken down by
category
-------
DATA REVIEW
After receiving the questionnaires and the exposed canisters, the
authors found several conflicting comments regarding descriptions of
the type of system installed. Consequently, a combination of
participant interviews, site visits and construction files were
reviewed to verify which category each house really belonged within.
All mitigated houses were reviewed in this manner which yielded some
additional insights for this study:
1) Several new home owners were under the impression that adequate
systems had been installed in their homes by the builders. Some of
these systems turned out to be only barrier techniques (sealing or
sub-concrete polyethylene). Perhaps more notable were homes that had
sub-slab perforate piping systems that were stubbed up in the
basement (most were sealed and one was open into the home). As an
interesting note, this survey was the first time some of the homes
were tested after occupation. For the purpose of the study, these
homes were moved into Category 4 with Category 3 retaining only
active sub-structure depressurization systems.
2) Two homes had utilized a sub-concrete mesh system where all of
the rest of the survey utilized foundation drains or a combination of
foundation drain and interior piping approaches for negative field
propagation. These two homes were more than twice the mean of the
other existing homes. Inspection of these homes indicated that the
problem was not necessarily with the membrane, but rather with the
installation. Fans were installed inside with extensive positive
side piping. Non-standard fittings were utilized, which discharged
beneath windows and near dryer vent openings. As the purpose of the
study was to distinguish between during- and post-construction
techniques as they are actually being installed, these two houses
were maintained in the Area 2 data pool. The balance of the
mitigated properties were carried out by the same RCPP listed
contractor. Although it is not the purpose of this paper to
distinguish between installers, it reinforces the need for proper
training of those involved in radon mitigation.
3) Some homes which had active mitigation systems installed, after
construction, had inoperable fans. These homes were moved to
Category 4 since the authors felt that they represented a passively
vented system as in a "radon ready" approach. At this time, no
attempt has been made to distinguish between barrier versus passive
systems. As an interesting side light, one homeowner insisted that
her system was operating because it was not unplugged. She was only
convinced when she inspected the fan. This system was installed
three years ago before the present EPA mitigation guidelines
requiring certain operating indicators for the homeowners were
developed (5).
RESULTS OF THE STUDY
What follows is a discussion of each area separately, culminating
-------
in a discussion of both areas combined. However, it should be kept
in mind that because of the smaller dat se of Area 2, conclusion
based upon this smaller data base may prove to be less convincing.
RESULTS FROM AREA 1
a comparison of the mean radon levels listed in Table 3 clea
indicates that mitigation during or after construction had ben ^ •
fact, the means of both Categories 2 and 3 were w!i|C:ial
rrent EPA guideline of 4.0 pCi/L,. these were
A
di
effects. In
below the current EPA guideline or t • v -u. meac
screening measurements taken at the lowest living area, current
approaches would recommend no further action by the homeowner (
6) .
TABLE 3 . RADON LEVEL MEANS AND STANDARD DEVIATIONS FROM AREA 1
Number Mean Standard
Category Description Deviation
22 9.8 5.26
1 Unmitigated ,
2 Post-construction mitigation 12 I J, 1.72
3 During construction mitigation 15 0.78 0.64
4 Radon ready ® 9.77 6.63
Homes that were mitigated during construction with active
sub-slab systems (Category 3) outperformed those active systei
that were installed after construction (Category 2). This
conclusion is based on a one-tail t-distribution at the 95%
confidence level.
Homes that were built with radon ready systems or had
passively vented systems showed statistically no benefit over
homes that had no mitigation work done.
RESULTS FROM AREA 2
As was seen in Area 1 using unmitigated houses as reference
(Category 1), mitigation which occurred during or after construction
showed significant beneficial reductions. Additionally, both the
mean of Categories 2 and 3 were well below the current screen action
level of 4.0 pCi/L (Table 4).
-------
TABLE 4. RADON LEVEL MEANS AND STANDARD DEVIATIONS FROM AREA 2
Category Description
Number Mean Standard
Deviation
1
2
3
4
Unmitigated
Post-construction mitigation
During construction mitigation
Radon ready
13
11
4
4
16.57 ± 8.39
1.43 0.86
1.49 1.74
10.27 8.71
Homes that were mitigated during construction with active
systems (Category 3) did not show a statistical difference from
those homes that were mitigated after construction (Category 2).
This result is certainly different from that obtained in Area 1.
This may be due to the smaller sample volume and the effect of
the non-mitigation guideline homes. One might also speculate
that the higher soil porosity in Area 2 allows equal propagation
of a sub-slab negative pressure field regardless of the use of a
perimeter drain system (Category 2) or a perimeter drain system
plus a sub-slab pipe network (Category 3).
Although the mean of radon ready homes (Category 4) in Area 2
was lower than non-mitigated homes (Category 1), no statistical
difference can be demonstrated. Therefore, the conclusion for
Area 2 is the same as for Area 1 in that no reduction benefit was
seen on radon ready installations.
RESULTS FROM BOTH AREAS COMBINED
In order to better answer the question that served as the
hypothesis for this paper, both data sets were combined. This
approach can be justified due to similarity of home construction,
unmitigated levels and soil type. The only difference noted,
however, was slightly different soil porosity. The comments made
above regarding unmitigated homes (Category 1) with respect to
mitigated homes (Categories 2, 3 and 4) remain the same when the data
is combined. That is, any active mitigation system is beneficial and
no benefit was derived from radon ready homes (See Table 5 below).
TABLE 5. RADON LEVEL MEANS AND STANDARD DEVIATIONS FROM BOTH AREAS
Category Description Number Mean Standard
Deviation
1
2
3
4
Unmitigated
Post-construction mitigation
During construction mitigation
Radon ready
35
23
19
12
12.32 ± 7.28
1.70 1.37
0.93 0.96
9.94 6.98
-------
When all data is combined, including the anomalies mentioned
earlier, one can determine statistically systems installed
during construction (Category 3) outperformed systems installed
after construction (Category_2) . Categories 2 and 3 are two
distinctly different populations as verified by the one tail
t-test at the 98% confidence level.
IMPLICATIONS OF RESULTS
interesting to note that the existing homes that were
mitigated after construction (Category 2) had a mean screening
result of 1.70 pCi/L ± 1.40. Although_this_is_at a level below
the current EPA action level of 4.0 pCi/L, it is right at
contemplated values for the new proposed guideline of 2.0 pCi/L.
(Ref 7) Although it is reasonable to assume upper floors of
these homes would be at lower concentrations of radon, it should
be noted that due to terrain and architectural plans, many of
these lower level floors contain family rooms and bedrooms. The
adoption of 2.0 pCi/L guideline for living areas may be difficult
to consistently achieve with mitigation techniques observed in
this study.
Similarly, the homes that had active mitigation system
installed during construction exhibited a mean result of 0.93
pCi/L ± 0.96. Within one standard deviation all of these
Category 3 homes would exhibit screening levels beneath both the
existing guideline of 4.0 pCi/L and the proposed guideline of 2.0
pCi/L.
The overall mean of new homes constructed with active systems
(Category 3, mean 0.93) would lend partial_credence to the
(Option 1) prescriptive approach proposed in the draft model
standards for new buildings. (Ref 8). However, the approach of
not requiring, or not emphasizing post—occupancy testing may
result in not identifying improper installations, as this study
did. This may, on the other hand, speak to proper education of
installers and the extension of the RCPP program to home builders
as well as specialty radon mitigation sub-constractors.
The inability to distinguish between "radon ready" systems
(Category 4) and non-mitigated homes reinforces the need for
testing within 30 days of occupancy for a non-activated radon
ready home. This is referred to as Option 2 of the Draft Model
Standards for New Buildings. Furthermore, the results of
Category 3 indicate the ability to reduce levels to below 2.0
pCi/L once the radon ready system is made active by addition of a
fan. It would be prudent to emphasize testing after actuation of
£}ie system fan for the same reasons as indicated above.
Homeowners' understanding of proper system operation was
inadequate in some cases. Interviews with participants indicated
little information was passed on from previous homeowners or
building contractors. This comment is more pertinent with
-------
respect to homes which were constructed with radon ready systems.
In this case, some homeowners felt that a complete system had
been installed. This can be dealt with either in a regulatory
manner or perhaps a greater emphasis can be placed on the present
Radon Contractor's Proficiency Program and particularly the
Mitigation Guidelines (5).
The data made available from this study will, with further
evaluation, offer opportunities to assess differences between
finer points of mitigation installations. A more detailed review
of homes in Categories 2 and 3 that fell outside the standard
deviation of the mean can be made to assess these installation
differences. A comparison of individual results to soil porosity
and soil gas measurements can also be made in order to assist in
developing a predictive model, at least for this geological area.
Furthermore, a more detailed review of Category 4 homes needs
to be made to determine which radon ready approaches may offer
the most cost effective benefit.
-------
REFERENCES
1. Burkhart, J.F. and Huber, T.P., Surficial materials influence
on radon production and transport: A Colorado example. in:
Proceedings of Technical Exchange Meeting on Assessing Indoor
Radon Health Risks, DOE, Grand Junction, Colorado, September,
1989, Section N.
2. U.S. Soil Conservation Service, 1981. Soil Survey of El Paso
County Area, Colorado, U.S. Department of Agriculture,
Washington, D.C.
3. Scott, Glenn R. and Wobus, Reinhard A., Reconnaissance
Geological Map of Colorado Springs and Vicinity, Colorado,
pub. by U.S. Geological Survey, Reston, VA, 1973.
4. Phair, G. and Gottfried, D., The Colorado front range,
Colorado, U.S.A., as a uranium and thorium province, in J.A.S.
Adams and W.M. Lowder, eds., The Natural Radiatjr>n
F.nvi ronment. University of Chicago Press, Chicago, p. 7-38,
1964 .
5. Environmental Protection Agency, Radon Contractor Proficiency
Program, Radon mitigation guidelines, October, 1989.
6. Environmental Protection Agency Citizen's Guide, August, 1986.
7. Environmental Protection Agency, Technical Support Document of
the 1990 Citizen's Guide to Radon, August 16, 1990.
8. Environmental Protection Agency, Proposed model standards and
techniques for control of radon in new buildings, November 2,
1989.
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VIII-3
RADON REDUCTION IN NEW CONSTRUCTION: DOUBLE-BARRIER APPROACH
by: C. Kunz
Wadsworth Center for Laboratories and Research
New York State Department of Health
Albany, New York 12201-0509
ABSTRACT
A double-barrier design with the space between the barriers having
little resistance to gas flow is described for those parts of homes and
buildings that interface with the soil or surficial rock to reduce soil-gas
(radon) entry into structures. The outside or soil-side barrier interfaces
with the soil. A barrier placed on the soil under the subslab aggregate is
an important element in this design. This forms the outer barrier for the
floor. The subslab aggregate forms a permeable layer, while a plastic
membrane above the aggregate, the slab, and caulking form the inner barrier.
If hollow block are used, barrier coatings can be placed on both the soil
side and interior wall of the blocks, while the hollow space in the blocks
forms the permeable space. The hollow-block walls are connected to the
subslab aggregate to form a small interconnected permeable volume that can be
managed in the following ways to reduce soil-gas entry into the structure.
1. Sealed.
2. Passively vented to outdoor air.
3. Passively depressurized using an internal stack.
A. Actively depressurized.
5. Actively pressurized.
In addition to basements with hollow-block walls, the double-barrier
technique can be adapted to solid wall, crawl space and slab-on-grade
construction including various combinations.
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INTRODUCTION
In the long terra, substantial reduction in radon exposure can result
from improved new home and building construction techniques that reduce radon
entry. In addressing this approach to reducing radon exposure, the EPA has
published a report "Radon-Resistant Residential New Construction" (i) £n
which construction techniques to minimize radon entry in new structures and
to facilitate its removal after construction are described. This report is
the first edition of technical guidance for constructing radon-resistant
structures to be issued by the EPA, and they anticipate future editions as
additional experience and approaches become available. The EPA report
includes a section on barriers to reduce radon entry including wall coatings
sub-slab membranes, caulking, sealing and prevention of slab cracking. '
Another section discusses designs for post-construction active or passive
sub-slab ventilation. A primary element in these designs is a minimum of 4
in. of aggregate under the slab. The preferred material is crushed aggregate
with a minimum of 80% of the aggregate at least 3/4 in. in diameter. This
highly permeable bed under the slab is necessary for good communication in
the event that sub-slab ventilation is needed. The aggregate is placed
directly on the soil and represents a large permeable volume into which radon
can diffuse or flow from the soil and rock under and around the foundation.
The radon that accumulates in the permeable aggregate can then flow with
little resistance to any penetrations in the barriers above the aggregate.
These barriers include the membrane placed over the aggregate, the slab and
any caulking and sealing of the wall floor joint, cracks and penetrations.
Having a permeable volume between the soil and the barriers reduces the
effectiveness of the barriers. Barriers are most effective when interfacing
with the soil. A similar situation occurs when hollow blocks are used to
construct the foundation walls. Radon that infiltrates through the outer
wall and into the hollow cavity of the block walls can then flow with little
resistance to any penetrations of the inside wall barriers. Again, barriers
to radon entry are most effective on the outside or soil-side of the wall.
An indication that aggregate under the slab increases radon entry into
structures was obtained in a survey of over 6,000 homes in New Jersey (2).
The data collected in this study show a definite relationship between age and
radon concentration. On average, houses built since World War II tend to
have higher indoor radon concentrations than houses built between 1900 and
about 1945. Initially, it was suspected that newer houses had higher indoor
radon concentrations because newer houses tend to be tighter and have lower
air exchange rates. However, closer examination of the data indicated that
the differences in radon concentrations associated with tightness did not
fully account for the decline in radon concentration with increasing age in
20th-century houses. The authors speculated that the use of sub-slab
aggregate, which increased in the post-World War II era, could also
contribute to the higher indoor radon observed in newer homes.
It is difficult to determine the effectiveness of the barriers to radon
entry suggested by the EPA, when used in the passive mode, since it is not
possible to know what the indoor radon concentrations would be for a house if
the radon-resistant techniques were not employed. The initial results,
however, have led the EPA to conclude "that in the presence of a moderate-to-
high radon source, radon prevention techniques that are passive only may not
produce indoor radon levels consistently below 4 pCi/1." In a study of 15
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full-basement homes in New York State which were built employing radon-
resistant techniques in an area with above-average levels of indoor radon,
most of the homes required active sub-slab ventilation systems (3). The
results from the New Jersey survey and the initial results of the homes built
with radon-resistant construction indicate that sub-slab aggregate
interfacing directly with the soil or rock under a home can increase radon
entry into the home and decrease the effectiveness of barriers placed above
the aggregate.
DOUBLE-BARRIER CONSTRUCTION
It is the purpose of this paper to suggest a design for new home
construction that is more effective in reducing radon entry in the passive
mode but one that can be readily adapted to active mitigation systems if
needed. The design proposes to reduce soil-gas entry by using double-barrier
construction for the sub-grade structure of homes and buildings. A primary
element in this approach is to have a radon barrier under the subslab
aggregate at the soil interface.
The double-barrier approach is illustrated in Figure 1 for a basement
with block walls and a sump. The hollow space in the block walls is
connected to the subslab aggregate via weeping holes or some other low
resistance pathway for air flow, to form an interconnected permeable space
that surrounds the entire subgrade structure. Barriers to radon transport
such as membranes, coatings, caulking, sealing, etc., are placed on both the
soil side and inside of the permeable space. Since radon barriers are most
effective at the soil interface, most of the barrier effort should be
concentrated on the sub-aggregate and outside wall barriers. The barrier
below the aggregate may be a composite of materials such as cement, tar,
plastic film, fine sand, and clay. Barriers at the soil interface should be
resistant to both diffusive and convective flow. A special effort should be
made to seal the outside wall barrier at the wall-footing joint and the
barrier below the aggregate at the footing-aggregate and aggregate-sump
joints.
The double-barrier subgrade construction creates a reasonably small
volume between the inside and outside barriers that can be managed in several
ways to reduce radon entry. Without a barrier below the aggregate, the soil
and rock under and around the house will be directly connected to any
mitigation system used to reduce radon entry. The double-barrier approach
works toward decoupling this direct connection. For the double-barrier
system shown in Figure 1, passively venting the hollow-block walls to outdoor
air will allow outdoor air to flow with little resistance into the permeable
space. As gas from the permeable space is drawn through any penetrations in
the interior or upper barriers into the basement by indoor-outdoor pressure
differentials, outdoor air can flow into the permeable space with little
resistance. The outside air flow reduces the draw on soil-gas at any
penetration in the outer or below barriers and thereby reduces the flow of
soil-gas radon into the permeable space. Alternatively, the permeable space
could be treated by depressurization (passive or active) or pressurization
(active). For these approaches it would be best to not vent the block walls
to outside air. Radon entry reduction can then be accomplished by creating
either a reduced pressure or increased pressure in the permeable space.
Having created a reasonably small interconnected permeable space with sealing
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VENT TO
OUTDOOR AIR
SOLID ROCK
OUTSIDE WALL
BARRIER AT —
SOIL INTERFACE
CHANNELS
IN FOOTING
INSIDE WALL
BARRIER
DEPRESSURIZATION
OR
PRESSURIZATION
-SUMP
discharge
SEALS
SUMP
DRAIN
SUBSLAB
AGGREGATE
BELOW SUBSLAB AGGREGATE'
BARRIER AT SOIL INTERFACE
Figure 1. Double~barrier construction for a basement with sump.
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on both the soil side and inside, it is expected that, if passive venting
(using a stack through the house interior), active suction, or positive
pressure flow is necessary to reduce indoor radon to acceptable
concentrations, then relatively low flow rates would be successful.
An example for an active pressurization system would be to draw air from
ceiling vents in the highest level of the house and blow this air into the
permeable space between the double barriers (Figure 2). The fan could be
located in the basement and relatively low flow rates ("20 cfm) should
suffice. In this manner, heated air from the highest interior level of the
house would be used to pressurize the double-barrier system heating the floor
and walls of the basement while reducing heat loss via exfiltration from the
higher levels of the house.
It is of primary importance to ensure that water effectively drains from
the permeable substructure space between the double barriers. This can be
accomplished with a sump as shown in Figure 1. It may be necessary to grade
the soil forming the base of the subslab aggregate toward the drain tiles and
the sump to aid in preventing the accumulation of water in the subslab
aggregate. If it is possible to drain the subslab aggregate to grade or to a
sewer, then this drainage option could be used instead of or with a sump.
Solid pipe should be used and it should be sealed at the outside or soil-side
barrier.
Exterior footing drainage of gravel and/or perforated piping is used by
many builders and presents a problem to the double-barrier design approach.
The gravel and/or perforated piping of the exterior drainage system runs
around the outside perimeter of the wall-footing joint. It represents a
permeable volume in which radon can accumulate and flow to any penetrations
in the wall and wall-footing joint. To minimize radon entry, the exterior
drainage system should be drained to daylight or to a sewer and not connected
to the subslab aggregate and sump via weeping holes or other methods.
Connecting the exterior drainage system to the subslab aggregate would
provide a pathway for soil-gas radon to enter the permeable zone of the
double-barrier system. Exterior perimeter drainage systems increase the need
for careful sealing at the exterior wall-footing joint.
The double-barrier approach is illustrated for slab-on-grade and crawl
space construction in Figure 3. Drainage of water that might accumulate in
the sub-slab-on-grade aggregate can be accomplished using a sealed sump as
shown in Figure 1 or by drainage to grade or a sewer using solid pipe. If
the double-barrier system is not effective in the passive mode (sealed,
vented to outdoor air, or passively depressurized using stack ventilation),
then active pressurization or depressurization can be employed. When a
barrier is placed directly on the soil of a crawl space and the floor of the
house is sealed, one obtains a double-barrier system with the space between
the soil barrier and the floor being the permeable space. The crawl space
can then be vented to outdoor air or the crawl space can be sealed and
passively depressurized, or actively pressurized or depressurized. To reduce
the volume of air to be pressurized or depressurized, a permeable layer of
aggregate or other construction to form a permeable space with barriers on
both the soil side and house side can be used as shown in Figure 3. Sealing
the floor and using a double barrier at the soil surface results in a triple-
barrier system where the two permeable spaces could be treated independently.
-------
FAN
SUMP
]| | barrier at
SOIL INTERFACE
Figure 2. Double-barrier pressurization using interior air.
-------
VENT TO
OUTDOOR AIR'
tm
ZTZS
fill
a&dS
^_17TO
DEPRESSURIZATION
OR
PRESSURIZATION
\
BARRIER AT SOIL
INTERFACE
SLAB-ON-GRADE
E3
VENT TO
OUTSIDE AIR
DEPRESSURIZATION
OR
PRESSURIZATION
BARRIER AT SOIL
INTERFACE
CRAWL SPACE
Figure 3.
Double-barrier systems for slab-on-grade and crawl space
construction.
-------
For example, the aggregate could be passively depressurized and the space
below the floor could be vented to outdoor air.
SUMMARY
Radon-resistant construction designed to decouple houses from the soil
has been suggested and used in various forms. The EPA refers to constructing
a pressure break between the foundation and the soil. Brennan and Osborne
(4) suggested that a drainage mat be used to form an air curtain around the
foundation. A Denver builder excavates to a depth of 10 ft. and constructs a
crawl space under a wood basement floor (1). The crawl space is then
actively ventilated. Walkinshaw (5) constructs a shell inside the basement
and then ventilates the space between the interior shell and the basement
floor and walls.
The double-barrier approach described in this paper attempts to modify
normal building practices to be more radon-resistant at moderate cost.
Barriers under the aggregate and on the outside of hollow-block walls
interfacing with the soil and rock will be the most effective barriers in
reducing radon entry. The double-barrier construction creates a relatively
small permeable volume between the inside and outside barriers that can be
managed in several ways, either passively or actively, to reduce radon entry.
A kev element in this design is to maintain water drainage from the permeable
soace between the barriers and from around the foundation. There are many
tvoes and variations of house and foundation construction. Very often these
variations are dictated by the local and regional surficial geology. It is
not possible to describe a radon-resistant design readily applicable to all
types of construction and water drainage conditions. However, a better
understanding of how water drainage systems around foundations can increase
the potential for radon entry will enable builders to make water drainage and
radon-resistant construction more compatible. Double-barrier construction is
such an attempt to make water drainage and radon resistance work together.
The work described in this paper was not funded by the U.S.
Environmental Protection Agency and therefore the contents do not necessarily
reflect the views of the agency and no official endorsement should be
inferred.
-------
REFERENCES
Osborne, M.C., Radon-Resistant Residential New Construction, United
States Environmental Protection Agency, EPA/600/8-88/087, July 1988.
Task 3 Final Report, Sampling Design, Data Collection and Analysis,
Statewide Scientific Study of Radon, Prepared for the New Jersey
Department of Environmental Protection, Prepared by Camp Dresser and
McKee Inc., April 1989.
Demonstration of Mitigative Techniques in Existing Houses and New House
Construction Techniques to Reduce Indoor Radon, Prepared for New York
State Energy Research and Development Authority and the U.S.
Environmental Protection Agency, Prepared by W.S. Fleming and
Associates, Inc. (NYSERDA report in publication).
Brennan, T. and Osborne, M.C., Overview of Radon-Resistant New
Construction, In Proceedings of the EPA 1988 Symposium on Radon and
Radon Reduction Technology, Denver, CO, Oct. 1988.
Walkinshaw, D.S., The Enclosure Conditioned Housing (ECHO) System: A New
Approach to Basement Design, In Proceedings of The Fifth International
Conference on Indoor Air Quality and Climate, Toronto, Canada, Aug.
1990, Vol 3, p. 257.
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VIII—4
RADON CONTROL - TOWARDS A SYSTEMS APPROACH
Nuess, R. M. and Prill R. J.
Washington State Energy Office
Energy Extension Service
N 1212 Washington, Suite 106
Spokane WA 99201
ABSTRACT
The normal operation of a continuous mechanical ventilation system, incorporated
into a relatively airtight house, and designed to control pressure-differences, has
been demonstrated to provide sufficient control of radon entry in a two story
residential building.
This was accomplished via a "two-cell barrier-enhanced pressure-difference control
system."
Ventilation rates, energy usage, moisture levels, pressure-differences, and radon
concentrations were monitored. Changes in radon concentrations in several
building locations, as a function of distinct pressure-difference configurations, have
been measured.
Indications are that this design offers the new residential construction industry an
opportunity to realize affordable control of radon entry, while simultaneously
optimizing potentials for moisture control, energy efficiency, and control of other
indoor air pollutants.
INTRODUCTION
This project explores the use of an airtight building envelope (and separately
isolated airtight crawlspace) integrated with a continuously operating mechanical
ventilation system, to enhance pressure-difference control strategies for
minimizing soil-air entry into the indoor air.
-------
This approach seeks to obtain robust control of radon entry, while concurrently
optimizing potentials for several building design goals including: moisture control,
energy efficiency, control of other indoor air pollutants.
CONTEXTING ASSUMPTIONS
There are several primary design goals for the environment control system
"house:" safety, comfort, durability, healthy indoor air, and energy efficiency. These
goals are not only increasingly achievable, but can be mutually advantaged in a
manner that can reduce net system cost.
A systems approach that seeks to optimize a building's performance with regard to
several desirable performance qualities might well include several very successful
radon solutions.
The radon source of concern is soil-air. The primary goal with regard to control of
indoor radon is the prevention of soil-air entry into the indoor air. Radon is a
given component of soil-air though its concentration both varies from one site to
another and is not readily predictable. In one case, measurements of soil radon
within a distance of 9 meters varied by a factor of 250 (1). Hence, the degree of
soil-air entry control required is neither constant nor predictable.
Two conditions are necessary for soil-air entry:
• There must be openings in the building envelope that couple the soil-air to the
indoor air.
• There must be a driving force, a pressure-difference that results in a flow from
the soil-air zone into the indoor air zone.
While significant reduction of all coupling pathways from the soil zone is
reasonably achievable, elimination of them is not. It has been observed that even
very small openings are sufficient to allow unacceptable radon levels (2). Control
of pressure-differences may be the practical key to adequately limiting the entry of
soil-air pollutants, including radon. Envelope tightness may be most important for
its role in enabling and enhancing pressure-difference control.
The tight building envelope, coupled with a properly designed mechanical
ventilation system, can play a central role in a systems approach that incorporates
pressure-difference control to limit soil gas entry. The tighter the air barriers of the
system, the more effective the pressure-difference control for a given amount of fan
power. This dovetails nicely with the desirable advantages of a tight building
envelope for several other building performance purposes, including:
• Comfort - fewer drafts; minimal temperature stratification; reduced noise, dust,
pollen, insects.
• Energy efficiency - large net reduction in heating/cooling loads.
-------
• Moisture control - structural durability and reduced maintenance costs.
• Enhanced dilution/removal of pollutants generated indoors - via improved
ventilation effectiveness, control and capability.
Several of the design elements serve to advantage multiple design goals. This
should be recognized when attempting to allocate costs. For example, soil-air may
also contain other pollutants of concern, such as garbage gasses (methane),
herbicides, fungicides, pesticides, spores of soil fungi, etc. (3). The cost of preventing
soil-air entry should be life-cycled against the delivery of several health benefits.
Also, in this particular project, the cost of mechanical ventilation and the tight
envelope must be apportioned to comfort, energy performance, radon control,
moisture control, and control of other pollutants.
SPECIFIC HYPOTHESIS
The normal operation of a commercially available continuous mechanical
ventilation system incorporated into a tight house, and designed to control
pressure-differences, can provide sufficient day-to-day control-of those
pressure-differences (induced by weather, internal household activities, and
mechanical systems) to prevent entry of radon and other soil-air pollutants. This
can be reasonably accomplished by developing a "two-cell, barrier-enhanced
pressure-difference control system." (4).
BUILDING DESCRIPTION
In 1988 a tightly sealed and energy efficient two-story residential building was
constructed with the intent to exceed any energy performance standards currently in
place in the U.S. The building was among those instrumented and continuously
monitored for one year as part of the Residential Construction Demonstration
Program (RCDP), a multipurpose research and development effort of the
Bonneville Power Administration and the Washington State Energy Office. As an
RCDP Cycle II Future House, the expected energy performance of the building was
designed to exceed that required by the Northwest Power Planning Council's Model
Conservation Standards by 30%.
The building was constructed in Spokane, WA. Spokane has a winter outdoor
design temperature of 4°F (-15°C), 6882 normal heating degree days, and 411 normal
cooling degree days. Spokane weather has the characteristics of a mild arid climate
in the summer and a cold coastal climate in winter. Winter solar potentials are
limited by both the climate and the site. The building was calculated to have an
annual need of 2.5 kWh/ft2 (97 MJ/m2) for space heating.
-------
16 200 megajoules per year 97 MJ/(m • yr)
total thermal load
useful solar + appliance gains ~
useful appliance gains
kWh 1500
5400 MJ
month
3600
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Figure 1. Predicted space heating profile.
The building is of double-wall construction and the wall thermal resistance is
approximately R45 (.126 W/[m2*K] ). This insulation level extends from the ceiling
to the concrete footing, except as interrupted by doors and glazing (Figure 2). The
glazing area is 328 ft2 (30.5 m2) and is 18% of the conditioned floor area 1780 ft2 (166
m2). Fifty-five percent of the glazing faces south. The glazing thermal resistance is
approximately R4 (1.5 W/[m^*K]). The ceiling is insulated to R60
(0.095 W/[m^*K] ). The continuous thermal envelope is completed by R25
( 0.227 W[(m2*K]) fiberglass batt insulation laid directly upon the ground (over a
gravel capillary break).
A continuous air barrier was established with the interior drywall by gasketing the
drywall to the wood framing and sealing any penetrations through the drywall.
Upon completion of construction, the building had a tested air leakage rate of 1.2 air
changes per hour (ACH) at an induced indoor/outdoor pressure-difference of 50
pascals. One year later it was tested at 1.4 ACH at 50 pascals. The measured Pacific
Northwest average is 9.3 ACH at 50 pascals (5). The vapor retarder was established
on the interior surface of the drywall with a rated paint. The glue in the laminated
subflooring provided the floor vapor retarder.
The building is divided into two distinct cells, that are atmospherically decoupled
from both each other and the outdoor air (Figure 2). The tightness and isolation of
these two "cells" enables pressure-difference control with the mechanical
ventilation system (and prevents contamination of air in cell 1 by air in cell 2. Cell 1
contains all occupied space, so that the breathable indoor air is contained in cell 1.
The volume of cell 1 is 16,500 ft^ (467 m^). Cell 2 is a plenum by which stale air
from cell 1 is removed. Though atmospherically decoupled, it is thermally coupled
to cell 1, so it provides warm floors. Cell 2 adds another 3000 ft* (85 m^) to the
conditioned volume.
-------
The first floor subfloor was the selected air barrier between cell 1 and cell 2. All
joints in the tongue and groove exterior grade plywood were sealed with urethane
sealant during installation. Special care was taken to identify and seal any holes
created in this barrier by the construction process (eg; temporary nailing for wall
bracing, sawhorses, measuring and cutting tables). A tracer gas was injected into cell
2 prior to carpet installation and two small air leaks were located using a detection
instrument.
HVAC SYSTEM
A small (5000 to 7000 btuh) commercially available integrated residential heat
recovery ventilation system (HPV) provides continuous ventilation, partial space
sDace cooling, water heating, as well as the desired pressure-differences (6).
^e unit cOTSists of a water heating tank and a space conditioning module (SCM).
The SCM contains 2 constant speed fans, 2 coils, and utilizes a reversible
refrigeration cycle to provide heating or cooling via the same ductwork. During the
winter heating cycle, heat is extracted from stale exhaust air and delivered to either
the domentic hot water tank or the mixed air supply. In summer, heat is extracted
from the mixed air supply and either exhausted outside or used to heat domestic
water.
recircl
IWMMfMssmi
wswi«
Figure 2. Exhaust Air Side.
Figure 3. Supply Air Side.
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On the supply air side, two 60 ft (18 m) long by 4 in (10 cm) diameter PVC earth tubes
provide filtered outdoor air which is mixed with recirculating air before it passes
over the supply-side coil and is distributed to individual living areas by fan F3
(Figure 3). TTie earth tubes are buried approximately 4 ft (1.2 m) below grade and
serve to temper both winter and summer air.
On the exhaust air side, stale indoor air is removed from kitchen and bathrooms by
fan F1 and ducted to cell 2. From this point it remains isolated from cell 1. The stale
air travels across cell 2, then exits via a sealed duct which leads to the SCM.
Continuous operation of fan F2 (SCM exhaust fan) is necessary to maintain a lower
pressure inside the SCM than in the mechanical room, so that no leakage back into
the indoor air occurs. After passing through the SCM the air is exhausted above the
roof line.
TWO-CELL, BARRIER ENHANCED PRESSURE-DIFFERENCE CONTROL
Cells 1 and 2 are isolated from each other, from the outdoor air, and from the indoor
air; by accessible and maintainable air barriers. Sealed ducts allow controlled air
passage. Continuous mechanical ventilation removes stale air from cell 1 and
delivers it outside via cell 2. Depending on which fans are selected to operate, cell 2
can be either pressurized or depressurized relative to cell 1 and/or the soil-air. This
project incorporated four fans in the ventilation system in order to enable
comparison between these two approaches, as well as other possible ventilation and
pressure-difference configurations:
• Continuously pressurize and flush cell 2: This is the baseline operating
condition. Fan F1 removes stale indoor air from cell 1, depressurizing cell 1
relative to outside and pressurizing cell 2. Fans F2 and F3 are part of the
commercial unit and operate at a constant speed. Fan F1 must produce a greater
flow than fan F2 in order to maintain cell 2 at a greater pressure than cell 1. A solid
state speed control allows adjustment of fan Fl. Dampers allow adjustment of the
flows through the SCM, but adjustment is limited to the range of flows required by
the SCM.
• Continuously depressurize and flush cell 2: Fan Fl does not operate, so fan F2
depressurizes both cell 1 and cell 2. Cell 2 is at a lower pressure than cell 1.
• Continuously pressurize cell 2: Fan Fl operates but no flushing of cell 2 occurs.
Cell 2 is decoupled from the exhaust loop, and stale air is removed directly from cell
1.
• Mimic typical housing leakage and ventilate: Increase the envelope equivalent
leakage area of cell 1 to typical levels by introducing deliberate openings in floor and
ceiling (The northwest average is 125 in^ (806 cm^). The measured cell 1 leakage
-------
area is 16-20 in2 (100-130 cm2). The ventilation system operates (decoupled from
cell 2). Leakage distribution can also be adjusted. Typical outside vents can be
installed in the crawlspace.
• Mimic typical housing leakage and do not ventilate: Increase the envelope
equivalent leakage area of cell 1 to typical levels by introducing deliberate openings
in floor and ceiling. Typical outside vents can be installed in the crawlspace.
ENERGY PERFORMANCE
Limited data is available at this time and results should be considered preliminary.
The building was completed and occupied during January of 1989. Shortly thereafter
extensive energy performance monitoring was begun by the Washington State
Energy Office, via a subcontract with W.S. Fleming Inc. Selected air and water
temperatures, air and water flows, relative humidities, and electrical energy usage
have been monitored and recorded (six second averages) on a multi-channel
datalogger. Data collection for the first year has been completed. Once the data are
analysed a more complete energy performance profile will become available.
Zoned electric resistance heaters were separately submetered. The integrated heat
recovery ventilation system, which provides continuous ventilation, partial space
heating, space cooling and water heating was also submetered. Electrical main and
submeter data were recorded by the author. For the one year period between March
4,1989 and March 3,1990, electric resistance heating used 1.4 kWh/ft2 (54 MJ/m2).
The HPV unit used 3.5 kWh/ft2 (135 MJ/ m2) for continuous ventilation, space
heating and cooling, water heating, and pressure-difference control. The HPV
system is estimated to provide 44% of the space heating load. This brings the total
cost of space heating to $216/year. The measured average Kwh consumption for
heating conventional electrically heated homes in the Pacific Northwest is 12,420
Kwh, which amounts to $596 (5).
MOISTURE PERFORMANCE
Humidity sensors (7) were calibrated and placed inside structural wood framing in
six locations prior to completion of construction. Two sensors were placed in the
attic, two in the walls, and two in the floor of cell 1. An attempt was made to select
locations with the greatest moisture potential; generally downwind from the
prevailing wind direction, shaded areas on the north side, and (for walls) high in
the building: ....
• Attic top chord - north side near center of building.
• Attic bottom chord - north side near center of building.
• East wall exterior framing stud - north side on upper level.
-------
30
Cell 2 Rim
February 1989 - March 1990
Attic Top Chord
N Wall E
N Wall W
Cell 2 Interior
Attic Lower Chord
5 ¦
0
FFFMJJAONNNDDDJJF FM
Month
Figure 4. Percent wood moisture content in six locations.
• West wall exterior framing stud - north side on upper level and near electrical
outlet.
• Warm joist in cell 2 - center of building.
• Cold joist cell 2 - next to north rim joist and on cold side of air-vapor barrier and
insulation.
Thirty-seven intermittent readings were recorded (approximately weekly during the
heating season) and corrected for temperature. Monitored moisture levels in all
locations dropped by the end of the summer following completion of construction,
and remained approximately constant through the following winter (Figure 4).
Moisture levels remained constant during the second winter as well.
The clock timer on the HPV unit is set to provide continuous exhaust ventilation,
so the unit's exhaust fan (F2) drawing stale air from cell 2 is always activated. If
there is a demand for water heating the compressor also operates. If there is a
demand for space heat or cooling the supply fan (F3) also activates. Both fans
operate at a constant speed and flows must be adjusted by dampers.
The baseline mode of operation has been to adjust fan F1 to maintain a slightly
lower pressure at the ceiling of cell 1 than that outside (thus also pressurizing cell 2).
This typically resulted in a 2-13 Pa lower pressure at the ceiling of cell 1 relative to
outdoors during space heating. The neutral pressure plane was maintained above
the ceiling of cell 1, there was no exfiltration, and therefore all air exchange was
induced by the HPV unit. The resultant pressure in cell 2 was generally 3 to 7
pascals greater than the pressure in cell 1, during space heating mode of operation.
The supply air fan (F3) operates during space heating and cooling, and tends to
pressuize the building, by increasing the flow of outside air through the earth tubes.
VENTILATION PERFORMANCE DYNAMICS
-------
However, when it is off (during penods of ventilation and water heating), fans F1
and F2 remain on, so the cell 1/cell 2 pressure-difference increases (10 to 20 Pa)
Additionally, a manual timer switch in the bathrooms enables short pulses of
greatly increased ventilation by boosting fan F1 to full power, and the cell 1/cell 2
pressure-differences become even larger (45 to 60 Pa)
Intermittent measurements by the author indicate that the mechanically induced air
exchange rate for the first year has been roughly 6 ACH, or equivalent outdoor air
supply for 11 persons at 15 cfm (7 L/s) per person Since the pressure in cell 1 was
lower than the pressure outside (therefore no exfiltration), all the air leaving cell 1
had to pass through fan Fl. A Kurz Model 435 Linear Air Velocity Transducer was
used to measure the mass flow of air in the duct downstream of fan Fl.
The purpose of fan F4 is to pull outdoor air through the earth tubes and provide
adequate outdoor air supply. It was found to be unecessary and was not operated
The negative pressure of cell 1 induced sufficient flow in the earth tubes. When the
unit's supply fan (F3) did not operate (ventilation and water heating modes) the
earth tube flow averaged 27 cfm (13 L/s). When the supply fan operated the average
earth tube flow was 57 cfm (27 L/s). Approximately one third of the outside air
supply was via the earth tube. Envelope infiltration, due to the induced negative
pressure of cell 1, provided the remaining outside air.
The pressure-difference control under these conditions appears to have been very
robust Though pressure-differences were not continuously monitored, they were
frequently observed during cold and windy periods. No reversals of the desired
pressure-difference directions were observed.
CONTROL OF RADON
RADON PHASE ONE
Five continuous radon monitors (CRMs) were placed in the same location for five
days to establish a comparison baseline The monitors were then placed in five
different locations in the building for a thirteen day period between November 11,
1989 and November 23,1989. Fan Fl was off during the first part of of this period, so
that fan F2 depressurized both cell 1 and cell 2 relative to outside
After the first 112 hours, Fan Fl was activated and adjusted to maintain a slightly
lower pressure at the ceiling of cell 1 relative to outside during the space heating
mode This resulted in a 10 to 60 Pa greater pressure in cell 2 (depending on the
HPV system's operating mode at time of read)
Cumulative CRM data were recorded intermittently and averaged over each elapsed
time period Thirty-two readings were recorded Average radon levels in cell 2
decreased dramatically when fan F2 was activated, average radon levels in cell 1 also
-------
showed a tendency to decrease (Figure 5)
Pressure-Difference Between Cells 1 and g
AP cell 2 < cell 1
AP cell 2 > cell 1
Radon Levels In Cell 2 y/A
Radon Levels In Cell 1 (4 locations)'
¦1110
•925
¦ 555
¦ 370
AP. houBB < outside
10
Cumulative Hours - October 1989
Figure 5 Radon levels in five locations.
RADON PHASE TWO
Two CRMs were placed in separate locations within cell 1 (CRMs la and lb) and two
CRMs were placed in separate locations within cell 2 (CRMs 2a and 2b). Hourly
radon averages were recorded for the three month period between 17 February and
21 May 1990. During this period/ the baseline system configuration (continuously
pressurize and flush cell 2 while depressurizing cell 1) was held constant for the
first 23 days Then 9 deliberate alterations in system configuration were made. After
each alteration the system was returned to the baseline configuration, before the
next alteration was initiated. Upon completion of the 9 alterations the system was
returned to the baseline configuration for 22 days.
The alterations had powerful effects upon Cell 2 radon levels, and clear effects upon
radon levels in Cell 1. Effects of wind, rainfall, and temperature did not appear to
have noticeable influence on radon levels, except that Cell 2 radon levels may have
showed some indication of response to temperature. Nonetheless the effect was
subtle relative to the effects of system operation.
The baseline system configuration and the alterations to it are discussed below, and
referenced in the following graphs.
-------
Radon Responses to System Alterations
February 17 to March 20,1990
120+
100+
Beginning Baseline
Alteration 1
80+
o
Q.
60+
cell 2
40+
cell 1
204
02/27/90
Hourly Data
Figure 6. Baseline and Alteration 1.
Baseline. The baseline operating condition was established for 23 days, from 2/17 to
3/11. During this period the average radon concentration in cell 1 was on the order
of 1 pCi/1. The average radon concentration in cell 2 was 7 pCi/1. Intermittently
recorded cell 2 pressures ranged from 1 to 7 pascals greater than those of cell 1. The
average was 3 pascals. Cell 1 was 7 to 15 pascals lower in pressure than outside. The
average was 9 pascals.
Alteration 1. Fan F1 was turned off on 3/11 at 10:20 am. The pressure in cell 2 had
been greater than the pressure in cell 1, but now shifted to about 30 pascals lower
than cell 1, since F2 now pulled air through the cell 2 plenum. In two hours radon
levels in cell 2 had increased by a factor of three. Radon levels in cell 2 averaged 29
pCi/1. Radon levels in cell 1 increased also to an average of about 2.5 pCi/1. On
3/17, six days later, fan F1 was turned back on. Pressure in cell 2 returned to 3-4
pascals greater than cell 1. Radon levels in cell 2 dropped by a factor of three in
three hours and returned to baseline levels.
-------
140
120-
100-
80-
O
Q.
20
•i
-W-
ft)
Alteration 2
Radon Responses to System Alterations
March 21 to April 23,1990
I
Alteration 3
Alteration 4.
60-
cell 2
cell 2
cell 1
V**v""Vw\|
nAaaeBfi
! SiVi! 1!!
03/21/90
03/31/90
03/26/90
04A)5/90
04/1090
04/2CV90
04/15/90
Hourly Data
Figure 7. Alterations 2,3, arid 4.
Alteration 2. On 3/29 fan F1 was turned off again for approximately 34 hours. F2
continued to operate, but the duct connection from F2 to cell 2 was disconnected
and exhaust air taken from cell 1 instead. The ductwork joining the two cells
remained open. Cell 2 was atmospherically coupled to cell 1, but was decoupled
from the ventilation loop. During this condition the cell 1 pressure was 10 pascals
lower than the outdoor pressure and cell 2 was about 7 pascal lower than than the
outdoor pressure. Hence, both cells sucked on the ground, but only cell 1 recieved
ventilation. Cell 1 radon levels increased by a factor of 12 to an average peak of 12
pCi/1. Cell 2 radon levels increased by roughly a factor of 20 to an average peak of
120 pCi/1. When the system configuration was returned to the baseline, radon
levels quickly returned to baseline levels.
Alteration 3. On 4/4 fan F1 was turned off for 62 hours. Also F2 and F3 were turned
off. There was no ventilation. The ductwork joining the two cells was sealed to
atmospherically decouple the cells from each other. Radon levels in cell 2 rose
gradually (whereas in the previous alterations they had risen abruptly) to a peak of
-------
66 DCi/1. Then Fl, F2, and F3 were reactivated and radon levels in both cells
returned abruptly to baseline levels. The pattern of a more gradual rise in radon
S£7so2 to occur in the cell 1 radon levels which rose to over 5 pCi/1. The
gradual rise is assumed to be attributed to soil recharging and the slower response
related to the lesser stack pressures.
The three fans were activated 62 hours after the initial alteration However cell 2
remained atmospherically decoupled from the ventilator.cycle (F2 drew exhaust atr
from cell 1), as well as isolated from cell 1 by the sealed ductwork. TTte condition
was that cell 2 was pressurized by fan F1 but there was no fishing of the air in cell 2.
The resultant pressure in cell 2 was 45 pascals greater than that in cell 1. Radon
levels returned to baseline in about 6 hours, hence were already at baseline levels
when the ductwork was reconnected and the system configuration returned to
baseline.
140
1204
100+
s
o
Q.
801
Radon Responses to System Alterations
February 17 to March 20,1990
..Alteration 4
Ending Baseline
lA/VA
05/14/90
04/24/90
0504/90
0509/90
05/19/90
Hourly Data
Figure 8. Alteration 4 and Baseline.
Alteration 4.. Fan F1 was turned off. The system was altered as described in
alteration #2 for roughly 24 to 30 hours, then returned to the baseline configuration.
This process was repeated six times. In each case cell 2 radon levels responded as
they had in alteration #2.
-------
Baseline. The baseline operating condition was restablished for 22 days, from 4/29
to 5/21. During this period the average radon concentration in cell 1 was less than
one pCi/1. The average radon concentration in cell 2 was about 2.5 pCi/1.
There is some uncertainty associated with the radon measurements. The CRMs
were research instruments that were not calibrated immediately prior to these
measurements. However, they were compared to each other by operating them in
the same location for six days at the beginning of this project. All 4 CRMs tracked
radon levels consistently (Figure 9).
ajto T
xoo
1JO
pCi/1
\£X>
OJK>
OA)
i ft • 4 » « r a *1011
1C to 21 Baptombtr 1M9
Figure 9. Radon instrument comparisons.
Several months after the project they were again compared to each other, and it was
discovered that only CRM la had a correctly operating air pump. This CRM was
then compared for about 30 hours to a Pylon AB5 with a PRD, which had been
recently calibrated with a Pylon Calibration Standard. The two monitors tracked
radon fluctuations consistently. When the data from this project was later
reviewed*, it was discovered that CRMs lb and 2b had diverged widely (radon
levels declined) from their respective matched pairs and never recovered. These
were suspected to be the points of pump failure. Data from these units was
removed from the data set for the time periods after their responses suggested pump
failures.
CRMs la and 2a did respond in a consistent manner throughout the entire
measurement period. Fortunately one was located in cell 1 and the other in cell 2. It
was also fortunate that CRM la - which was recording the lowest and least variable
radon levels - was also the CRM that continued to have a correctly operating
pump and was compared to the calibrated Pylon instrument after the study. Both
the consistent response of these two remaining CRMs to the repetitive nature of
alteration #4, and the similarity of their ending baseline responses to their starting
baseline responses, suggest that these two CRMs responded with acceptable
accuracy to radon fluctuations throughout the study.
* This study was not funded and was conducted as time allowed.
-------
, „ .he nump on CRM 2a began to fail. The data set suggests
It is not Known when the p , during the study period and likely failed after
that CRM 2a was operating corre y g
the study period.
COST
It is very difficult to assign costs to the radon prevention and mitigation feature (
this building, since virtually all the features that control radon also enhance
performance, durability, comfort, and the control of other pollutants The .ene.r®^
energy-only payback for these features is 10 to 20 years. The building's usefuHif h
also been extended due to such features as the vented rain screen designed t & S
siding life, and the elimination of air transported moisture into the exterior° 0X^Gnc*
Since these features primarily address energy, and there is a clear energy oavlTwf
them, it can be argued that there is no incremental cost for the control of rid *
entry. The building cost $80,824, approximately $45 to $48 per square foot °n
INDICATIONS
1 Control of soil-air entry with pressure-differences using a continuous mechanical
ventilation system incorporated into a tight house is readily achievable.
2 The initial radon experiment indicates that the radon source at this building
location may be sufficient to allow the demonstration of radon control, as well as
the comparison and evaluation of the impact of different pressure-difference
configurations on radon entry.
3. Airflows through the HPVAC-80 can be reduced by installation and adjustment of
dampers so that the flows necessary to maintain required pressure-differences can be
reduced (within the limits of the range of flows required by the HPV). The target
goal of maintaining soil gas entry control with a mechanical system operating at .35
ACH may be achievable at this level of envelope tightness.
4. Careful attention to air-vapor barrier installation can enable sufficient control of
moisture levels in the Spokane climate, even under conditions of constant and
relatively large pressurization.
FUTURE DIRECTIONS
• Evaluate this concept at sites where the known soil radon source is high.
• Evaluate the degree of pressure-difference necessary to control radon and
determine the associated air exchange rates, climatic conditions, and energy costs.
• Compare different pressure-difference scenarios and their impact on radon levels.
-------
U.S. EPA & New York State Energy Office, Reducing Radon in
Structures/Training Manual, unit 2, page 4.
Brennan T (1990) Evaluation of Radon Resistant New Construction Techniques,
Preprints of The 1990 International Symposium on Radon and Radon
Reduction Technology, Vol. 5, p.l.
White J H (1988) Radon-Tust Another Soil Gas Pollutant? Presented at 81st
Annual Meeting of the Air Pollution Control Authority, Dallas TX, USA, June
1988, p.5.
This concept was built upon conversations with Bo Adamson, Lund Institute of
Technology, Sweden. Also discussions by Sven-Olov Ericson and Hannes
Schmied (1987) Modified Design in New Construction Prevents Infiltration of
Soil Gas That Carries Radon. American Chemical Society,
0097-6156/87/0331-0526.
Sensible Living for the 9Q's. Bonneville Power Administration, BPA
DOE / BP-23821-4 10/90.
HPVAC-80 Envirovent, DEC International Inc., Therma-Stor Products Group,
Madison, WI.
HS-1 Humidity Sensors and Model J-3 Moisture Meter, Delmhorst Instrument
Co., Boonton, New Jersey, U.S.A.
-------
MINI FAN FOR SSD RADON MITIGATION IN NEW CONSTRUCTION
by: David W. Saum
Infiltec
Falls Church, VA 22041
ABSTRACT
Subslab depressurization (SSD) systems in new houses constructed
with well sealed slabs and good aggregate beds will probably achieve
excellent radon mitigation performance with fans that are considerably
smaller than the 80 Watt fans that are currently recommended. This
paper describes the development, testing, and evaluation of a low
power radon mitigation fan for installation in new houses. This "mini
SSD fan" uses only 10 Watts of power, and its radon mitigation
performance is shown to be almost as good as the larger fans. Since
the EPA plans to recommend the installation of SSD systems in hundreds
of thousands of houses that are constructed each year in high radon
areas, the long term energy savings involved in reducing fan power
could involve billions of dollars. In addition, the mini SSD fan
lowers the installation cost of the radon mitigation system, and this
might encourage more builders to follow with the EPA recommendations.
-------
BACKGROUND
One strategy for radon mitigation in new construction is for
builders in areas with high radon levels to install SSD systems in all
the houses that they build. Experience with SSD in new construction
suggests that when houses are constructed with SSD combined with a
well sealed foundation and a porous aggregate layer, then the
performance of SSD radon mitigation has been shown to be excellent.
Although many houses with these systems would not have had a radon
problem above the EPA action level of 4 pCi/L, even the lower level
houses would probably experience some radon mitigation. Since most
radon exposure occurs in these lower level houses (due to their large
numbers), the net result of installing SSD in all houses in high radon
areas is a substantial decrease in radon exposure for occupants of
these houses.
A primary objection to installing SSD systems in all houses would
be the costs, both for initial installation and for energy and
eventual replacement. This objection could be reduced by using the
lowest cost components consistent with good radon mitigation
performance, long life, and low energy costs. This paper describes
the development, test, and life cycle cost evaluation of a low power
SSD radon mitigation fan for installation in new houses. This "mini
SSD fan" uses 10 Watts of electric power compared to the 80 Watts of
the standard fan, and its performance is shown to be almost as good as
the larger fans. Since the EPA plans to recommend the installation of
SSD systems in hundreds of thousands of houses that are constructed
each year in high radon areas, the long term energy savings involved
in reducing fan power could involve billions of dollars, and these
energy savings might provide some assistance in solutions to problems
such as global warming and U.S. energy independence. In addition, the
mini SSD fan lowers the installation cost of the radon mitigation
system, and this might encourage more builders to follow the EPA
recommendations.
PREVIOUS EXPERIENCE
Although SSD is by far the most common radon mitigation
technique, the details of its operation are not entirely clear and the
size of the fan that is necessary for effective mitigation is not well
understood. As a result, most mitigators use 80 Watt fans for most of
their mitigation jobs, and most of the industry experience is based on
the use of these fans. For new house construction, it seems that
smaller fans might be successful if the builder provides a good site
preparation by installing at least a 4" depth of large diameter
aggregate under the slab, and by sealing all slab penetrations.
Several documents have been written about construction details for
radon resistant new construction, including: a new ASTM standard1, a
Bonneville Power Administration report2, and the EPA new construction
guide3. Unfortunately, these documents do not contain much discussion
of fan performance versus size or of life cycle costs. The EPA will
soon issue recommendations on model code language for radon resistant
new construction, and there will be a technical support document with
life cycle cost calculations.
However, there is one study that suggests that very small fans
might provide good performance: the February 1990 EPA Symposium Paper
1
-------
Radon Mitigation Performance of Passive Stacks in Residential New
Construction4 by Saum and Osborne. This research showed that one
builder's passive stacks (SSD systems without any fans) offered
significant radon mitigation performance in both summer and winter.
Table 1 shows a summary of the radon mitigation results for this
study. The passive stacks reduced the radon levels by about 66%, and
45 Watt SSD fans reduced radon levels by an average of 98% of the pre
mitigation levels. Most performance reductions in these passive stack
houses are thought to be due poor installation of the stacks, or to
depressurization of the basement by leaky forced air return ducts
which reversed the passive stack pressures. This suggests that a
small SSD fan would boost the passive stack pressures enough to
overcome most of these residual mitigation problems.
MINI FAN DESIGN
ThP first step in this project was to design a low power and low
+* -pan fKaf nmild be used in a conventional new home SSD system. It
cost fan that could be usea in * u ingtall a 4 inChes of coarse
was assumed tha^ t b penetrations, and run a stack
aggregate under the .lab, sea slabPand exiting though the roof,
pipe (3 or 4 PVC) up tnroug pasalve stack effect, the stack
In order to take advantage or V the house. The desirable fan
-sidered to
rSSStk sags *- —
, eon -Fan dpsian is shown in Figure 1. The
The final mini S consists of a fan motor, fan housing,
conventional radon fan system¦ noise, the conventional 45 or 90
and two pipe couplings., inclined blade, but 10 Watt fans are so
Watt radon fans use a 1backward xncliM^o a^, ^ ^ ^
quiet that a conventio mini fan is built into one pipe
simplicity and low®r ' combined fan housing and pipe coupling,
coupling which serves as a ,gtg of a high quality 10 Watt, 3"
The final mini fan ^esig . 3„ diameter PVC ring, and enclosed in
diameter, axial fan moun mien a 3„ gtack pipe iS used, the fan
a 3" flexible pipe coupliing. If a 4« stack pipe is used, then
housing serves as the pipe ^oup Q- couple the fan to the 4"
«" 3" ?!£C? 3 »" be recon-ended because of the low
stack. The use of 3 stacks wou^ ^ consistency with the use of 3"
air flows, the reduced c <'lled in houses. To complete the radon
plumbing stacks alre ^ aauae capable of monitoring the low
control system, a P*®s^ag developed from the commercially available
expected stack pressure . .. ator The Fancheck is a modified Dwyer
"Fancheck" type pressure ^^cator. ^ ^ # tapered clear_
air flow meter that consist Fancheck indicates pressures greater
plastic tube The ^"^ona^Fancheck^i^.^ ^ ^ ^ ^ ^
than about 0.2 wc, but ball s0 that it indicates pressures of
SSD fan by using a much lighter mj.i
* » ft 1.1 /¦*
only a few hundredths " wc,
2
-------
COST ESTIMATES
FAN PARTS COSTS
The parts cost of the mini SSD fan is less than $20, and the
modified pressure gauge is about the same cost (about $10) as the
Fancheck gauge. Therefore the mini SSD fan could be sold to builders
for considerably less than a standard radon mitigation fan system
consists of an 80 Watt fan with 2 pipe couplings (about $150), and a
pressure indicator ($10) . It is anticipated that the mini SSD fan
system could be sold to builders for about $75, half the cost of the
standard 80 Watt fan system.
LIFE CYCLE COSTS
The largest cost savings are in the life-cycle costs, not the
initial installation costs. Table 2 shows a comparison of life cycle
costs between a 10 Watt SSD fan and a standard 80 Watt SSD fan. Three
types of recurring costs are assumed: electric cost for running the
fan continuously, wasted heat costs for warming house air that is
exhausted through the fan, and fan replacement costs. These
calculations show that the mini SSD fan would cost about $29 per
average year, while the standard 80 Watt fan would cost about $135 per
year to operate continuously.
If builders follow the forthcoming EPA recommendations that all
houses in radon prone areas have radon resistant features built into
them, then it is reasonable to assume that at least 100,000 of the
1,000,000 new home built every year will have SSD fans installed.
Under these assumptions, the estimated savings for installing a 10
Watt fan, rather than an 80 Watt fan, are shown to be $11 million in
the first year, $476 million in 10 years, and $4.6 billion in 30
years. .
RADON MITIGATION PERFORMANCE
Ideally we would like to know the performance trade-off between
fan power and radon mitigation performance under a wide variety of
conditions: geology, climate zones, building practices,
heating/cooling system variations, contractor variables, failure
modes, etc. With this type of data, we could begin to make a
calculation of the cost per life saved with different SSD fan systems.
Unfortunately, this type of study is far beyond the scope of this
project.
PASSIVE STACK PERFORMANCE
The passive stack experiment data shown in Table 1 suggests that
the mini SSD fan radon reductions in new houses should be somewhere
between the performance of the passive stack systems (about 66%
reduction) and the performance of the 45 Watt fan systems (about 98%
reductions). It seems likely that if the performance of the passive
stacks is based on the extremely weak forces of stack effect, then the
performance of 10 Watt fan systems will be much closer to the 45 Watt
fan systems than to the passive stack systems. We believe that is not
unreasonable to assume that the mini SSD fan will give at least a 90%
average reduction of elevated radon levels in new construction,
3
-------
assuming the recommendation on the subslab aggregate layer and sealing
is followed.
MINI FAN PERFORMANCE IN ONE HOUSE
Only one prototype fan was available for experiments until last
month when an additional half dozen prototype units were received from
the fan manufacturer. The original prototype has been tested for
several months under worst case conditions: an older house with no
slab sealing and a poor subslab aggregate bed. These conditions were
expected to be much worse than would be found in new houses built for
radon resistance. The data from these tests is shown in Figures 2-5.
These Figures show that even in an older house with no sealing of
cracks and an uneven subslab aggregate bed, the 10 Watt mini SSD fan
lowers the radon level from 10 pCi/L to 2.1 pCi/L (a 79% reduction)
versus a reduction to 0.8 pCi/L (a 92% reduction) for a 45 Watt fan'
Figures 2 and 3 show the performance of the two fans over a month as
the fans are being cycled off and on every 3.5 days. Figures 4 and 5
show the averages of 4 on/off cycles so that the variations are
smoothed out. Note that both fans reduce radon levels within a few
hours after the fans are turned on, but the larger fan seems to have
depleted the radon under the slab more extensively than the smaller
fan, and it takes longer for the radon levels to build up in the house
after the larger fan is turned off.
PERFORMANCE LIMITATIONS
Some general limitations of SSD fans that may apply to the mini
SSD fan have not been fully investigated yet: 1) problems with large
slabs, 2) problems when sand or other low porosity aggregates are used
below slabs, and 3) problems when the soil below the slab is very
porous. These situations are not well understood for even the
standard SSD radon mitigation systems. It seems likely that this type
of problem could be addressed by written guidance that would be
included with the mini SSD fan systems.
FUTURE DEVELOPMENT PLANS
The future plans for development of the mini SSD fan call for more
field tests of the prototype, refinement of the design, field tests
with cooperative builders, certification (UL or equivalent), volume
purchase agreements, and eventual sale to builders and mitigators.
DISCLAIMER
The work described in this paper was not funded by the U S
Environmental Protection Agency and therefore the contents do not
necessarily reflect the views of the Agency and no official
endorsement should be inferred.
REFERENCES
1. Radon Control Options for the Design and Construction of New Low-
Rise Residential Buildings, Standard Guide 1990, American Society for
Testing and Materials, Philadelphia, PA, 1990.
4
-------
2. Nuess, M., Northwest Residential Radon Standard Project Report#
DOE/BP-1273,Bonneville Power Administration, Portland OR, October
1989.
3. Osborne, M.C., Radon-Resistant Residential New Construction,
EPA/600/8-88/087, July 1988.
4. Saum, D.W., Osborne, M.C., Radon Mitigation Performance of Passive
Stacks In Residential New Construction, Presented at the 1990
International Symposium on Radon and Radon Reduction Technology,
Atlanta, 1990.
5
-------
Table 1 Radon Mitigation Performance Data from Passive Stack Study
BOUSES WITH PASSIVE STACKS, NO FANS
Test •
Hous«
No.
"T5S
126
162
40
53
209
105
42
84
206
206
Stack
Open
(PC1/L)
573
0.1
4.7
8.8
1.1
1.2
0.6
1.9
4.9
2.9
0.6
Stack
Sealed
i£Ci/L}_
6.1
13.6
8.5
12.8
2.7
6.5
1
9
5
19
2
Radon
Reduction
1*1
95%
99%
45%
31%
59%
82%
67%
80%
16%
85%
75%
AVERAGE:
2.5
8.1
70%
Comment Comment
summer data
winter data
duct leaks, poor communication
duct leaks, poor communication
duct leakage
duct leaks, poor communication
winter - duct leakage
summer - duct leakage fixed
BOUSES KITB FANS IN PASSIVE STACKS, FANS OFF
Test
House
Mo.
T53f
308
308
221
181
233
237
184
Stack
Open
(pCi/L^
4.5 na
8.0
1.5
6.7
na
7.4
12.7
Stack Radon
Sealed Reduction
(pCi/L?
13.0
na
33.5
12.0
7.4
18 na
13.7
26.4
(%)
Comment
86%
na
76%
88%
9%
1.9 na
46%
52%
AVERAGE:
6.3
17.7
64%
BOUSES tTITB FANS IN
PASSIVE STi
Test
Fan
Stack
Radon
House
On
Sealed
Reduction
No.
(pCi/L)
(PCi/L)
(%)
363
0.1
13.0
99%
308
0.4
na
na
308
0.2
33.5
99%
221
0.3
12.0
98%
181
0.1
7.4
99%
233
na
18 na
na
237
0.6
13.7
96%
184
0.8
26.4
97%
winter
summer, duct leakage
winter, duct leakage
winter, duct leakage
stack in unheated garage
not used, fan inside basement
stack in unheated garage
duct leakage
Comment
winter
AVERAGE:
0.4
15.1
98%
summer, duct leakage
winter, duct leakage
winter, duct leakage
stack in unheated garage
not used, fan inside basement
stack in unheated garage
duct leakage
COMMENTS AND CONCLUSIONS
1. This data was collected by an EPA Office of Research 6 Development
funded study conducted in 1989-90 and performed by Infiltec and Ryan Homes.
2. All radon measurements are averages of one or more weeks of hourly
continuous radon data collected with Pylon or Femtotech monitors.
3. Passive stacks lowered radon by about 1/3, fan systems by about 1/40
4. Passive stacks provided mitigation in summer as well as winter.
5. Passive stack performace appeared to be reduced by duct leaks and
poor subslab communication causing blocked pipes.
6. Passive stacks provided some mitigation in all cases.
7. A low power fan to assist the passive stack might overcome many of the
the problems caused by house pressures or poor communication.
8. Limitations of study: one builder (Ryan Homes), one region (D.C. Metro),
small number of houses (16), one HVAC type (heat pump).
9. All radon control systems were installed by the builder without
supervision by a radon mitigation expert.
10. Houses with summer and winter data aye included twice in averages.
6
-------
Table 2 Life Cycle Costs of the Mini SSD Fan and Standard SSD Fan
CALCULATION ASSUMPTIONS:
GENERAL ASSOMPTIONS;
Electric rate
Gas rate
Oil rate
Fuel cost escalation
Inflation rate
New houses built
House lifetime
New houses with SSD
New houses with SSD
HEATING ASSUMPTIONS;
Heating degree day
Gas efficiency
Gas heat for 1 cfm
Oil efficiency
Oil heat for 1 cfm
Elec. efficiency
Elec. heat for 1 cfm
Heat pump efficiency
Heat pump for 1 cfm
Avg fuel for 1 cfm
FAN ASSOMPTIONS:
Fan power
Exhausted house air
Exhaust heat cost
Fan life
Fan & gauge cost
Fan replacement cost
VALUE
$0.08 per kwh
$0.60 per therm
$1.00 per gallon
0.00%
0.00%
1 million/yr
30 years
10.00% of total
0.1 million/yr
VALUE
5000 deg F days
70%
$1.12 per year
70%
$1.36 per year
90%
$4.60 per year
200%
$2.08 per year
$2.29 per yN /
STANDARD FAN
80 watts
25 cfm
$57 /yr
11.42 yrs
$150
$250
COMMENT
approximate U.S. electric rate
approximate U.S. gas rate
approximate U.S. oil rate
to simplify long term calc.
to simplify long term calo.
approximate D.S. average
used as long term limit
SSD - SubSlab Depres. system
this is a guess
COMMENT
approximate U.S
degree days
gas furnace and ducts
gas cost/yr/cfm of exhaust
oil furnace and distribution
oil cost/yr/cfm of exhaust
elec. furnace & ducts
electric cost/yr/cfm exhaust
heat pump and distribution
heat pump cost/yr/cfm exhaust
average cost/yr/cfm exhaust
MINI FAN
TO
watts
3.125 cfm
$7
11.42 yrs
$75
$175
COMMENT
continuous electric
this is a guess
avg oil, gas t elec.
rated 8 100,000 hrs
cost to builder
fan plus install
ECONOMICS FOR SINGLE BOOSE:
STANDARD FAN MINI FAN $ aXVIHO » 8AVHIQ
electricity (/yr) $56 fT )4t CT%
heat loss (/yr) $57 $7 $50 88%
replacement (/yr) $22 $15 $7 30%
Cost (/yr) $135 $29 $106 78%
Cost (/house life) $4,056 $885 $3,172 78%
ECONOMICS FOR U.S.:
Costs (1st year)
Costs (10 years)
Costs (30 years)
STANDARD FAN
$14 million
$608 million
$5,882 million
MINI FAN
$3 million
$133 million
$1,283 mil11ion
$ 8AVIMO
$11 Billion
$476 million
$4,599 million
NOTE:
1. Costs of pipe installation and slab sealing ignored since they are common
to both SSD fan systems.
2. Exhaust air leakage of 25 cfm for 80 Watt fan is a guess.
3. The estimate of 10% of new home builders installing SSD systems assumes
the EPA will recommend new home SSD in radon prone areas.
7
-------
Power Cord
Fan Blade
T Exhaust
V \ \
Fan Motor
3" Pipe Coupling
3" Pipe Section
Figure 1 Vertical Cross-Section Schematic of Mini Fan
8
-------
\
b
Q.
C
o
*o
n3
CH
Waynesboro, VA house, 20' years old, finished basement
Walk-out basement, some aggregate under slab, no slab
Single point SSD system draws 0.06" wc with 10 Watt
4 weekly fan cycles, fan on for 3.5 days each week
Fan turned on
Fan tuined off
W
sealing
1990 Julian Day
Estimated lower mitigation limit of 2.1 pCi/L
— Radon (pCi/L)
Figure 2 - Mitigation Performance of 10 Watt Fan
20
Waynesboro, VA house, 20' years old, finished basement
Walk-out basement, some aggregate under slab, no slat
Single point SSD systfem draws 0.7" wc with 45 Watt '
4 weekly fan cycles fan off for 3.5 days each week
Fan turned on.
an
Fan shut off
Q.
15
35
5
25
Day
— Estimated lower mitigation limit of 0.8 pCi/L
— Radon (pCi/L)
Figure 3 - Mitigation Performance of 45 Watt Fan
9
-------
Waynesboro, VA house, 20 years old, finished basement
Walk-out basement, some aggregate under slab, no slab sealing
Single point SSD system draws 0.06" wc with 10 Watt fan
Average of 4 week cycles, fan on for 3.5 days each week
Fan turned on
Fan turned off
207
208
Day
Estimated lower mitigation limit of 2.1 pCi/L
Hourly radon averaged aver 4 weeklong fan on/off cycles
Figure 4 Average Mitigation Performance of 10 Watt Fan
20
15
10
Waynesboro, VA house, 20 years old. finished basement
Walk-out basement, some aggregate under slab, no slab sealing
Single point SS0 system draws 0.7" wc with 45 Watt fan
Average of 4 week cycles, fan off for 3.5 days each week
turned on
Fan turned off
25 26
Sunday 8/5
Average Days
— Estimated lower mitigation limit of 0.8 pCi/L
— Average of 4 weeklong fan on/off cycles
Figure 5 Average Mitigation Performance of 45 Watt Fan
10
-------
VIII—6
BUILDING RADON MITIGATION INTO INACCESSIBLE CRAWLSPACE
NEW RESIDENTIAL CONSTRUCTION
by
D. Bruce Harris and A. B. Craig
U. S. EPA
Air and Energy Engineering Research Laboratory
Research Triangle Park, NC 27711
and
Jerry Haynes
Hunt Building Corporation
El Paso, TX 79984
ABSTRACT Specifications for new residential housing
units for base personnel at Ellsworth Air Force Base, Rapid
City, SD, called for demonstrated radon levels below 4
picocuries per liter (pCi/L) before they would be accepted
by the Air Force. Hunt Building Corporation decided that it
would be cheaper to build radon control systems into all the
units than to have to retrofit some later. The Radon
Mitigation Branch of EPA's Air and Energy Engineering
Reasearch Laboratory assisted during the design and
installation of the active soil depressurization (ASD)
systems and followup measurements. The buildings utilized
below grade wood floor construction over an inaccessible
crawlspace because of the highly expansive soils. The
initial installations demonstrated the need for complete
sealing of the floor system. An effective quality control
scheme was instituted which tested the negative pressure
field established under every building and required
additional sealing until each corner of the floor was under
at least 2.5 pascals (Pa). Early data indicate that moderate
levels of radon (100 pCi/L) exist in the crawlspace when the
mitigation fan is off for several days and virtually none
when it is on. Results from several buildings are presented.
This paper has been reviewed in accordance with the U.
S. EPA's peer and administrative review policies and
approved for presentation and publication.
BACKGROUND
A major housing project which will be leased by the Air
Force at Ellsworth Air Force Base, Rapid City, SD, is being built
by the Hunt Building Corporation. The housing project has 828
residential units in 251 buildings, consisting of singles,
-------
duplexes, and quadruplexes. The area where the houses are being
built is known to be radon-prone. The Air Force had tested 30 of
their 2500 houses and found about 60% of them above 4 pCi/L. As
a result of this high radon incidence, the Air Force's initial
Request for Proposal (RFP) contained a radon performance clause
requiring the builder to test the houses before occupancy to
guarantee that they were below 4 pci/L. A unit testing below 4
pCi/L is accepted by the Air Force for occupancy and a 1-year
alpha track test is commenced. If radon levels in the living
area test below 4 pCi/L for the first year, then Hunt has met its
performance requirement and no longer has any responsibility, if
the house initially tests above 4 pCi/L, then Hunt must bring the
level below 4 pCi/L before occupancy. When the l year test
increases above 4 pCi/L, then the Air Force will stop payment
until the level has been brought below 4 pCi/L.
With limited radon control experience, Hunt Building
Corporation contacted EPA to seek advice on the best way to
construct these multifamily housing units to ensure radon levels
of below 4 pCi/L or to mitigate them to this level if they are
found to contain higher levels when tested. The decision was made
by Hunt to install a radon mitigation system in all units since
retrofit into an inaccessible crawlspace would be very difficult
and potentially expensive.
MITIGATION SYSTEM DESIGN
Most of the units are two-story quadruplexes with the lower
level built approximately 3 ft (1 m) below grade (Figure 1). The
-------
individual units are separated by a double wall for sound
deadening, but no firewall. Because the units are built on
expansive soils the Air Force is requiring that the lower floors
be treated plywood over joists with a crawlspace below. The
units are built with a 6 in. (15 cm) crawlspace between the
bottom of the joists and the clay under the units. The building
site is being excavated to a depth of 5 ft (1.5 m) and backfilled
with compacted glacial aggregate in an effort to stabilize the
ground and minimize movement. This is moraine till which is
quarried on site consisting of a moraine stone with a great deal
of fine sand and some soil in it.
After reviewing the various techniques which AEERL has
tested on the mitigation of radon in crawlspace houses, it was
recommended that the most cost-effective way to mitigate the
house with a high level of assurance of lowering levels to below
4 pCi/L was to use either suction under a polyethylene sheet in
the crawlspace or suction on the crawlspace itself. It was
decided that there was an excellent chance of making suction on
the crawlspace satisfactory by doing a thorough job of sealing
the plywood subfloor. The plywood is tongue and groove along the
8 ft (2.4 m) edge, and all 4 ft (1.2 m) edges are on joists. The
plywood is screwed to the joists. No outside vents are in the
crawlspace, and every effort is made to make the crawlspace as
airtight as possible. Moisture should be controlled by the active
mitigation system. The joint between the floor and the concrete
wall is sealed with polyurethane caulk. Any cuts through the
polyethylene and plywood for pipes are carefully sealed around
the pipe with polyurethane foam. Hunt has built a box in the
-------
joists under the bathtub so the bathtub trap does not penetrate
into the crawlspace and provide a possible radon entry route.
One suction pipe per unit is used. This 6 in. pipe, in the
wall between the two middle units of each quadruplex, extends
straight up to the fan in the attic and exits the roof
immediately above.
TESTING FIRST UNITS
Since the building season is short in South Dakota, testing
began as soon as the first crawlspace floor was installed. AEERL
sent a team to Ellsworth Air Force Base to install a temporary
fan on the system and to measure pressure reduction at the
various points of the crawlspace below the plywood floor. When
negative pressures can be achieved throughout the crawlspace as
measured in all four of the corners, the greatest distances from
the suction point, then no soil gas should be sucked into the
house. A 6 in. pipe was installed through the deck of a
quadruplex at the intersection of the central "party" wall and
the central beam which ran the full length of the unit. An axial
aligned centrifugal fan was mounted on the pipe with power
provided through a speed controller. An electronic manometer
measured the pressure under the deck at several locations. Once a
few small leaks had been sealed, at least -0.010 in. WC (-2.5 Pa)
was obtained at each corner of the building and more than 1.0 in.
WC (248.8 Pa) fan suction was recorded.
A duplex was the second unit tested. No perimeter or
penetration sealing had been done so this provided an excellent
opportunity to test the effect the extra sealing had on the
suction obtained. No suction was detected at the corners and only
-------
0.2 in. WC (49.8 Pa) of fan suction was measured which was the
pressure drop through the floor opening. The fan suction was
monitored while the sealing crew proceeded to close the openings.
Little change was noticed until roost of the wall joint and the
pipe penetrations were closed. As the final openings were closed,
dramatic increases in the fan suction were seen. The installation
crew understood the need for carefully sealing all openings as a
result of this test. This effort also provided the basis for the
strict quality control and quality assurance program instituted
by Hunc.
Every deck was tested when it was sealed and all plumbing
activity was finished. A separate crew performed the tests and
repaired breaks in the seal. A temporary fan depressurized the
crawlspace and the sub-floor suction was measured. Any unit that
failed to draw at least 0.010 in. WC in the corners was checked
for leaks and resealed before additional construction activities
were allowed to proceed. All buildings completed so far have
exceeded the requirements when the seal was completed and a 6 in.
fan installed. It may be possible to reduce the power consumption
further by adding a speed control to the fans.
RESULTS
As the first units were finished, an AB-5 Pylon radon
monitor was used to check for radon in three units: a finished
one with an operating mitigation system, a unit with a finished
floor which had been sealed for 1 week, and a third with a just-
completed floor without final sealing. No radon was found under
the floor in the finished unit nor in the mitigation system duct.
-------
Likewise, the completed but not sealed unit had no measurable
radon in the crawlspace. The crawlspace under the sealed floor
did yield levels of 100 pCi/L. This is a moderate source
strength, but could be enough to elevate unmitigated units above
the EPA action level of 4 pCi/L because the shell of each house
is very tight and low dilution could be expected.
Acceptance testing of the first 130 unit section yielded
levels between 0.8 and 2.4 pCi/L except for a single unit which
had a carbon cannister reading of 16.0 pci/L. A check of the
system in this house found that the circuit breaker had been
turned off? consequently, the reading was really an indication of
the level that could have been expected if no mitigation system
had been installed. A retest with the fan operating showed the
levels reduced to 2.5 pCi/L. This fan inoperation showed that the
effort and commitment of Hunt to install the mitigation systems
and insist on an effective quality assurance program was well
worth the investment. Retrofitting mitigation systems into these
units would have been much more costly than doing it during the
building phase.
-------
unit 1
unit 2
unit 3
6-*- suction hble
Ix
crawlspace
unit 4
garage slabs
Figure 1. Quadruplex foundation plan
-------
VIII-7
THE EFFECT OF SUBSLAB AGGREGATE SIZE ON PRESSURE FIELD RyTF^jgjr.|j
by: K.J. Gadsby, T. Agami Reddy,
D.F. Anderson, and R. Gafgen
Center for Energy and Environmental Studies
Princeton University
Princeton, NJ 08544
and
Alfred B. Craig
Air and Energy Engineering Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
ABSTRACT
Four sizes of commercially available crushed blue gravel
aggregate (3/8, 1/2, 3/4, and 1 in. nominal diameter) were tested
in a laboratory apparatus designed to experimentally determine the
aerodynamic pressure drop coefficients of porous material such as
soil and gravel. Permeability values for crushed stone of 1/2 and
3/4 in. nominal diameter were found to be 10-20 times higher than
those reported in a previous study for river-run gravel of the same
nominal diameter. Pressure field extension of this aggregate, when
suction is applied to a single central suction hole (a practice
widely used for mitigating buildings with elevated radon levels by
the subslab depressurization technique) , is also generated based on
a disc flow model previously studied by the authors. Application
of the disc flow model to residences with both basements and slab-
on-grade construction is also described. Theoretical computations
indicate that the permeability of soil around the foundation walls
and periphery of the residence is a more crucial parameter
affecting the pressure field extension than the permeability of the
subslab gravel bed. The laboratory studies will be field verified
in new construction of schools and houses in the future.
This paper has been reviewed in accordance with the U.S.
Environmental Protection Agency's peer and administrative review
policies and approved for presentation and publication.
'This work was funded by the U.S. Environmental Protection
Agency under Cooperative Agreement No. CR-817013.
-------
PROBLEM STATEMENT
Subslab air flow dynamics provide important diagnostic
information for designing optimal radon mitigation systems based on
the subslab depressurization (SSD) technique. An earlier study
(Refs. 1 and 2) showed that subslab air flow induced by a central
suction point can be mathematically treated as radial air flow
through a porous bed contained between two impermeable discs.
Subsequently, it was suggested that subslab material commonly found
under residential buildings be categorized and tested in the
laboratory in order to deduce their aerodynamic pressure drop
coefficients. This would then permit the pressure field extensions
to be inferred which would be of practical and realistic importance
to radon mitigators. To this end, a laboratory apparatus was
designed and built which is described fully in Ref. 3.
The scope of this study was limited to four aggregate mixes —
No. 600, 601, 602, and 603 — provided by Vulcan Materials from
their Manassas Quarry. The physical specifications provided by
Vulcan Materials are given in Table 1. The aggregate is crushed
blue gravel, a material commonly used as subslab material for
residential and commercial housing.
This paper first reports aerodynamic flow coefficients of the
four aggregate mixes obtained from EPA's laboratory apparatus.
Subsequently, it describes how the disc flow model can be applied
to residences with both basement and slab-on-grade construction.
Finally, it shows generated pressure field extension plots for each
aggregate in the framework of the above model and discusses the
practical implications of these plots in the design of SSD systems.
EXPERIMENTAL RESULTS
The laboratory apparatus, described fully in Ref. (3), is
shown in Fig. 1. It consists of a straight length of 8 in.* PVC
pipe approximately 5 ft long to the bottom of which a 1/4 in.
aluminum removable screen is fitted. The screen, which slides in
and out along a groove machined into the PVC pipe, is perforated
with a pattern of 1/4 in. diameter holes to permit air flow. The
porous material is loaded into the test column from the top after
which another sleeve, containing flow straighteners and the air
supply inlet tube, is placed on top of the column. Air is supplied
to the system from the top and several pressure taps provide
information on the pressure drop in the porous bed as air flows
down through the porous bed in the test column. The total air flow
rate is accurately measured. The experimental procedure involves
* For readers more familiar with metric units, 1 in. = 2.54 cm and
1 ft = 30.48 cm.
-------
measuring the pressure drop (AP) through a known and predetermined
bed length (AL) for a specific value of total flow rate (q).
Several such tests are carried out over a range of q values for
each sample of aggregate and for different samples of the same
aggregate. A least-square regression finally provides estimates of
the permeability (k) and the flow exponent (b) of the aggregate.
Table 2 assembles results of the porosity experiments, three
different samples of each aggregate tested at least twice. This
involved choosing a volume of the aggregate material and then
finding the porosity by measuring the volume of water needed to
completely saturate each sample (Ref. 4). The values of porosity
(0) specified by the supplier and those obtained from the tests are
shown in Table 2. Note that, in general, standard deviation values
are less than 2% of the mean value, thereby indicating
reproducibility. As for the mean values of porosity, note that
those of aggregates No. 602 and 603 are close (within 10%) to those
quoted by the suppliers while those of No. 601 and 602 deviate by
as much as 20% from the quoted values. This relatively large
difference in porosity values has not been explained.
Table 3 presents the various experiments performed as well as
the values of k and b obtained by regression. The third column
presents values of (cwhich are needed to estimate the Reynolds
number which gives an indication of the nature of the flow regime
(whether laminar or turbulent) (Ref. 4). The value of gravel
nominal size was assumed to be the diameter d,, and was taken from
the supplier's specifications (simply the mean value), while the
corresponding values of porosity 0 were taken from the experiments
(Table 2). Two or three samples of each aggregate mix were tested
and 10-20 runs were performed for each mix. This duplication was
to ensure that experimental results obtained were representative
and robust.
The range of air flow rates at which the experiments were
performed for each aggregate and the corresponding range of
resulting Reynolds numbers are also shown in Table 3. Generally,
the flow is turbulent when Reynolds numbers are greater than about
10 (Ref. 4). In the experiments, the Reynolds numbers were higher
than 10 but less than 50, a range of Reynold numbers which is
expected for SSD air flow in gravel beds of residential buildings
(Refs. 1 and 2) . A further advantage of the Reynolds number range
chosen is that the statistical determination of the parameters k
and b is likely to be more accurate. Other than for aggregate No.
603, the R2 values of the regression model are very good (R2 > 0.9) ]
This is an indirect indication that the experimental design was
satisfactory. The relatively lower R2 values for mix No. 603, which
is the largest gravel, could be a result of the fact that, in order
to keep Reynolds numbers low, the pressure drop was measured close
to the sensitivity of the instruments (which was 0.25 Pa or 0.001
in. WC).
-------
The mean and the coefficient of variation (CV) in percentage
values for k and b are also given in Table 3. Permeability values
of mix No. 600 are around 10'7 m2, gradually increasing to about 7
x 10"7 m2 for mix No. 603. It is worth pointing out that mixes No.
601 and 602 (1/2 and 3/4 in., respectively) have k values which are
10-20 times larger than those of river-run gravel of the same
nominal diameter, as reported in a previous study (Refs. 1 and 2).
A possible explanation for this is that river-run gravel beds have
lower porosity; i.e., they tend to pack more closely (Refs. 1 and
2) . This important finding suggests that crushed aggregate is more
suitable as a subslab material fill than river-run gravel for
buildings to be mitigated using the SSD system since the former is
likely to have a larger pressure field extension from the suction
hole. The flow exponent b does not vary too much with mix. The
relatively higher value for mix No. 602 does seem surprising since
both No. 601 and 603 have lower values for b. A possible reason
for the low b value for mix No. 603 is that it had relatively more
fines in the aggregate. CV values for k are low (less than 3%),
while those for b are high, as much as 12% for mix No. 603.
PRESSURE FIELD EXTENSION
This section gives results of computing the pressure field
extension under the slab when the four crushed gravel sizes are
used as subslab fill material, using the disc flow model described
in Ref. 1. Consequently, the following conditions are assumed:
only one suction hole is used,
the suction hole is located at the center of the slab,
the slab is circular, and
the edges of the slab communicate uniformly with the
ambient air.
Figure 2 illustrates how flow conditions in an actual house
with a basement can be visualized in the framework of the disc
model. The square basement is approximated as a circle of radius
r0 while the extra flow path H through the soil around the house is
accounted for by effectively increasing the circle radius to R.
Thus the flow is assumed to occur between two impermeable discs,
the upper end being the underside of the basement slab and the
lower end being the soil beneath the gravel bed. Since the
material under the slab is gravel while the extra flow path around
the sides of the house is through soil of different permeability
than that of the gravel, this model was modified to represent a
disc made up of two materials of different permeabilities: soil
between radii r0 and R, and gravel between r0 and the central
mitigation pipe. As pointed out in Ref. 1, the flow regime would
likely be turbulent through the gravel bed and laminar through the
soil.
-------
conseauentlv the total pressure drop AP (in head of water)
across the two-material bed is equal to the pressure drop through
the gravel plus the pressure drop through the soil. From equations
derived in Refs. 1 and 2:
AP = -r-
where kg - permeability of the gravel bed,
v - kinematic viscosity,
g - gravity
p - density,
q - total air flow rate,
h - thickness of the gravel bed,
b - flow exponent,
r0 - radius of the basement
r, - radius of the suction pipe,
k, - permeability of the soil surrounding the house,
R - total radius of flow (equal to that of the
basement and of the extra flow path through
the soil).
Note that the pressure drop given by Equation (1) is not the
entire pressure drop to be overcome by the mitigation fan. The
pressure drop due to entrance effects into the mitigation pipe and
that due to the straight pipe, fittings, and bends could account
for as much as 50% of the entire pressure drop in the mitigation
system.
Two types of construction were studied: slab-on-grade and
basement houses. In the framework of the disc model, the
difference between the two is solely in terms of the extra flow
oath through the soil. Basement houses will tend to have higher H
values (see Fig. 1) than slab-on-grade houses; consequently the (R-
r) value will be correspondingly different. The following values,
deemed representative, have been chosen in all calculations that
follow:
slab-on-grade: R « r0 + 1 »
basement house: R « r0 + 3 m
Also selected were r, ¦ 5 en (i.e., a 4 in. diameter suction
-------
pipe for the mitigation system) and a value of h « 0.05 m (which is
based on experience and supported by tests in an actual house
described in Ref. 1). Equation 1 cannot be directly used to
compute the required suction pressure for different values of
basement radius r0, since the total air flow rate q is not an
independent variable. It is determined by the practical criterion,
which is that the pressure below the actual slab (i.e., up to a
radius r0) should be lower than the ambient pressure P, by an amount
larger than the depressurization of the house arising from natural
causes (e.g., wind, stack effect, heating, ventilation, and air
conditioning system (HVAC) depressurization) . A realistic range
for this depressurization is 3-10 Pa (Ref. 5). Consequently, the
flow rate q should be such that a pressure drop equal to this
depressurization occurs in the outer portion of the disc containing
soil; i.e., between R and r0. Since the flow is laminar in this
region, q is computed from:
where AP is the prespecified minimum depressurization below
all points of the slab expressed in head of water.
The value of q is then used in Equation (1) to calculate the
required suction pressure at different values of slab radius r0.
Note that the numerical value of kt, soil permeability, greatly
influences q and consequently the pressure field extension. Hence
the two following cases were chosen in order to study the
sensitivity of the pressure field extension on the type of boundary
fill material (Ref. 6):
(i) k, = 10"* m2, corresponding to sand and gravel mixtures,
(ii) k, « 10*10 m2, corresponding to fine sands.
Additionally, a value of 10 Pa has been selected as the
required pressure drop through the soil between radii R and r0 due
to reasons discussed above.
Figures 3 and 4 present the computed suction pressures for
cases (i) and (ii), respectively, for the four gravel sizes tested
and for both basement and slab-on-grade type construction. Note
that differences in field extension between gravel sizes for the
subslab bed material, especially mixes No. 602 and 603, are much
less important than those resulting from soil type selection.
Figures 3 and 4 show that there is an order of magnitude difference
in pressure requirements between the two construction types; it is
lower for case (ii), lower permeability soil. This fact highlights
the importance of having a ring of low permeability soil around the
foundation walls and the periphery of the building. There is an
(2)
-------
^ i pressures between basement and
important difference in su but fchig ig go fQr the
slab-on-grade constr This because most of the pressure drop
tighter soil (Fig. 4) . This « ^ practically no dro£
occurs across the ou r g Thus theoretically, for fine soils
through the grave' « fie*ld extension is very large (radius
(case 11) , the pre nractice. looseness in packing of
?heasoilths£or?-circuiting of flow paths or small holes or cracks
in the slab will drastically decrease this value.
Finally Fig. 5 presents the total air flow rate for case (i)
Finally, rxy. J v t construction. These flows are
for slab-on 9ra^e aravei size since they have been computed from
impendent of the^ that the pressure drop in the
STin^ 'consisting of
bXeen^hf slab-on-grade and basement cases differs by almost a
factor of three.
FUTURE WORK
Qi.ndv was undertaken to experimentally determine the
This study W ents (permeability and flow exponent) of
aerodynamic t mixes of commercially available stone. The
four crushed agg g ^ ^ noininai diameter, are gravel sizes
sizes, ra"g^9«,ubslab fill for residences and large buildings. An
often usfsu^sif.JsJudv is that permeability values of 1/2
irop°rtant finding o gravel were 10-20 times higher that those
Vort in a Srevious study for river-run gravel of the same
reported in P ield validation of the computed pressure field
nominal dx*®?*®r' . oratory test results is important and such tests
eXten^entlv' beS Panned in newly constructed schools,
are cur:re;ntly b g houses> The reSults presented here
should^be used with caution until such time that the apparatus and
experimental design are more fully validated.
ACKNOWLEDGEMENTS
n H^rrie and R de silva contributed generously during the
^ construction of the laboratory column. Useful
discussions wi?h A. Cavallo and R. Sextro are also acknowledged.
-------
NOMENCLATURE
b
flow exponent
dv
equivalent diameter of gravel
cv
coefficient of variation
g
acceleration due to gravity
h
thickness of the porous bed
k
permeability of gravel
AL
length of porous bed in flow direction
AP
pressure drop
P
pressure
q
total volume air flow rate
R2
coefficient of determination of regression
Re
Reynolds number
R
total radius of air flow path
ra
effective radius of basement
r.
radius of suction pipe
P
density
V
kinematic viscosity
0
porosity of porous bed
Suffix
a
ambient, air
g
gravel
s
suction pipe, soil
w
water
-------
REFERENCES
1 T A Reddv K J. Gadsby, H.E. Black III, D.T. Harrje, and R.G.
sixtro -Simplified Modeling of Air flow Dynamics in SSD Radon
BttiwtionTystVms for Residences with Gravel Beds," report
submitted to U.S. EPA, February 1990.
9 v -r radsbv T A. Reddy, R. de Silva, and D.T. Harrje, "A
Simplified Modeling Approach and Field Verification of Airflow
Dynamics ^lfsSD Mitigation systems," presented at the 1990
International Symposium on Radon and Radon Reduction
Technology, February 19-24, Atlanta, 199 .
3 T A Reddv, K.J. Gadsby, D.F. Anderson, and R. Gafgen,
"Experimental Laboratory Tests on Vulcan Crushed Aggregate,"
Report submitted to AEERL, U.S. EPA by the Center for Energy
and Environmental Studies, Princeton University, m January
1991.
4 M. Muskat, thp Flow of Homogeneous Fluids Through Porous
Media. McGraw-Hill, 1937.
5 EPA Manual: Reducing Radon in Structures, 2nd Edition, United
States Environmental Protection Agency, Office of Radiation
Programs, Washington, D.C., 1989.
fi WW Nazaroff, B.A. Moed, and R.G. Sextro, "Soil as a Source
of indoor Radon: Generation, Migration, and Entry," Chapter 2,
T>irtnr> and Decay Products in Indoor Air, W.W. Nazaroff and
A?V? Nero (Eds.), John Wiley & Sons, 1988.
-------
TABLE 1. QC ANALYSIS OF VULCAN MATERIALS CRUSHED AGGREGATE AS SUPPLIED BY THE COMPANY
Loose
Vulcan % Passing Screen Size Bulk Void
No. Description 1-1/2 1 3/4 1/2 3/8 3/16 3/32 Density Volume
600 3/8 in. clean 100 90 23 5 91.8 49.3
601 1/2 in. clean 100 83 27 3 1 89.4 50.6
602 3/4 in. clean 100 93 27 7 2 95.1 47.5
603 1 in. clean 100 94 40 6 2 1 93.0 48.6
-------
TABLE 2
COMPARATIVE RESULTS OF POROSITY TESTS
Vulcan
No.
Nominal
Size (in.)
Porosity
From Present
Supplier Tests
600
3/8
0.493
0.403 (0.006)*
601
1/2
0.506
0.419 (0.011)
602
3/4
0.475
0.436 (0.015)
603
1
0.486
0.452 (0.009)
~Values in parentheses are standard deviation values.
-------
TABLE 3. SUMMARY OF EXPERIMENTAL DATA
Number
of Range of Number Regression Permea-
Vulcan Nominal d» Samples Flow Reynolds of Obser- Model bility Exponent
No. Size 0 Tested Range Numbers vations R2 k x 10* b
(in.) (mm) (1/min) (m2)
600 3/8 2.36 3 6 - 21 5 - 18 20 0.91 104.4 1.14
(2.5)* (7.0)
601 1/2 3.03 2 19 - 28 20 - 30 11 0.99 193.6 1.15
(0.4) (3.5)
602 3/4 4.37 2 19 - 28 29 - 42 10 0.92 336.3 1.29
(1.2) (10.9)
603 1 5.62 3 19 - 30 37 - 58 16 0.84 683.9 1.17
(1.2) (12.0)
* Values in parentheses are coefficient of variation (CV) values where CV = (Mean value/Standard error of
the mean) x 100
-------
Figure I. Sketch of the flow apparatus. Ust of components ts attached.
-------
Key for Figure 1
Main Column - Schedule 40, PVC, 8 in. Pipe
Test Rig Panel
Support Blocks
Test Material Cavity
Lower Sleeve
Movable 1/4 in. Aluminum Screen
Upper Sleeve
Collection Bin
Assembly Bolts
Short Pipe Section
End Cap
"0" Ring
Flow Straighteners
Pressure Taps
Urethan Tubing
Tubing Union
Miniature Solenoid Valves
Solenoid Panel
Valve Selector Switch
12 Volt DC Power Supply
Manifold
Manifold Panel
Transducer Selector Switches
Pressure Gauges
Interchangeable Connector Tubing
Gauge and Flowmeter Panel
High Pressure Transducer
Low Pressure Transducer
DVM Connector
Digital Voltmeter (DVM)
Wiring Harness
Air Supply
Shutoff Valve
Flow Control Valve
Flowmeters
Tubing from Flowmeter to Column
-------
Air flow
path
Mitigation
/pipe
So
Basement slab
Gravel bed
Figure 2. Disc model of a SSD mitigation system in a basement house.
-------
SLAB-ON-GRADE
V600
V601
V603
0 1—i—i—i—i—i—i—i—i—i—i—i—i—i—i—i—i—i—i—i—i—i—i—i—
0 10 20 3D -10 50
SLAB RADIUS (m)
BASEMENT
CL,
LJ
o:
uj
Be
V600
V601
V602
V603
—I—i—i—i—i—i—
30 40
BASEMENT RADIUS (m)
so
Figure 3.
Pressure field extension for case (i) : Jc, - 10"* m1 for
the four gravel mixes tested. Soil flow path length is
1 m for slab-on-grade and 3 m for basement houses.
-------
SLAB-ON-GRADE
o
.CL
taJ
CO
to
y
c/i
£
11.-1-
V600
V601
V602
V603
10 20 30
SLAB RADIUS (m)
50
K3.S-
BASEMENT
o
li-
en
tn
u
£
xw-
KL3H
102
J0.H
V600
V603
V602
BASEMENT RADIUS (m)
Figure 4. Pressure field extension for case (ii) : k, *« 10"10 ml for
the four gravel mixes tested. Soil flow path length is
1 m for slab-on-grade and 3 m for basement houses.
-------
SLAB-ON-GRADE
80-
70-
60-
50-
LU
cn
40-
30-
20-
10-
SLAB RADIUS (m)
BASEMENT
u-) i i i i i i i i i i i i i i—|—i—i—i—i—|—i—i—i—i—
0 10 20 30 40 50
BASEMENT RADIUS (m)
Figure 5. Total air flow rates for case (i) : k, - 10"' m2, computed from
Eq. (2) .
-------
Session VIII:
Radon Prevention in New Construction -- POSTERS
-------
VIIIP-l
RADON PREVENTION IN RESIDENTIAL NEW CONSTRUCTIONi
PASSIVE DESIGNS THAT WORK
by> C. Martin Grisham, B.S.
National Radon Consulting Group
New London, CT 06320
ABSTRACT
Various approaches and criteria have been developed and promulgated
by EPA concerning radon prevention during new construction of private
residences. Yet, very little information is available which describes
cost effective passive radon reduction techniques for residential new
construction. This paper will present two case studies of the evaluation,
design, installation, and performance of successful passive radon
prevention in new construction. Both case studies make extensive use of
EPA recommended new construction techniques which, when utilized
synergistically, provide long term average radon concentrations of less
than two picocuries per liter of air in the lowest livable areas of each
residence.
-------
RADON PREVENTION IN RESIDENTIAL NEW CONSTRUCTION»
PASSIVE DESIGNS THAT WORK
INTRODUCTION
Recent studies of the performance of new construction, passive radon
reduction systems have been conducted (1). However, very little
information is available about specific approaches taken to install cost
effective passive systems that work. By using the EPA's approach to radon
resistant new construction (2,3) as a general guide, two residences have
been effectively protected from radon entry through the use of completely
passive radon mitigation strategies.
The benefits associated with the implementation of passive radon
reduction systems during the construction of a structure include<
a. A radon reduction system which is more aesthetically appealing
than a similar retrofit system. Many times, during a retrofit operation,
portions of the system will be visible to the homeowner, or the system
will reduce effective storage space. This is particularly apparant when
retrofit systems pass through storage closets in route to the roofline.
b. The ability to install a completely passive system which would
require no on-going operating expense and would provide for minimal energy
loss.
c. The ability to consistently provide annual average radon
concentrations in the lowest liveable floor of the structure below 2.0
pCi/1 of air.
d. And, through judicious use of on-site workers and a close
relationship with the builder, the ability to provide the most cost
effective means to attain the lowest reasonably achievable radon
concentrations.
This paper is organized to provide a method of approach to new
construction through the description of cost effective new construction
techniques implemented in two residences in Connecticut. The approach
begins with the site and building plan reviews. Then, a description of
the development and implementation of mitigation strategies is provided.
The discussion then concludes with an assessment of the performance of
each system and the associated costs for each completed project.
-------
SITE EVALUATION
The site evaluation is typically the first step when considering the
use of radon resistant new construction techniques. £ Sl"
evaluation that the actual decision is made whether radon resistant
techniques should be used. During the site evaluation various sources of
data are reviewed to determine the likelihood of radon occurance. Should
the likelihood exist, new construction techniques to reduce radon entry
are implemented.
The site evaluations for both projects began with the acquisition of
various pieces of data available through federal, state, and local
aovernment agencies. Such sources of data included topographical maps,
bedrock and surface geology maps, aeroradioactivity maps, and state and
local radon testing program results.
After a thorough review of the data available through the above
sources the decision to implement radon resistant new construction
techniques was made based on the following information.
a Each residence is located in geologic areas documented to have
a hiah percentage of homes (>15%) with radon levels in excess of the EPA's
?e"ieS aS?on level of about 4 plcocurles per liter of air (4,5).
b Radon levels in other homes within the immediate geographic
region of each structure have shown the presence of radon in excess of 20
pCi/1 of air. This was evidenced by actual test results from homes in the
immediate neighborhood.
c The background gamma radiation at each site is in excess of
600 counts per minute (6).
4 Each home buyer was keenly aware of the potential for radon
related'health risks due to long-term exposure to radon and wished to
decrease family exposure to levels as low as reasonably attainable. In
both cases the home buyer wished guarantees of annual average radon levels
below 2.0 pCi/1 ot air.
The use of direct soil gas measurements prior to construction were not
considered to be a predictor of post construction indoor radon
concentrations. Therefore, soil gas measurements were not conducted prior
to construction ot the structure.
-------
BUILDING PLAN EVALUATION
Once the site assessments had been conducted and enough evidence was
available to support the implementation of radon reduction techniques, a
thorough examination of building plans was conducted. Examination of
building plans reveals the nature and extent of thermal bypasses, the
potential characteristics of the sub-slab area, the availability of
verticle chases for locating the vent stack, and details about the
foundation and slab which might have an affect radon entry.
HOUSE A BUILDING PLAN
Figure 1. House A Foundation and Sub-Slab Piping Network
-------
As oar, be seen in Figure i., House A is an irregular shaped
contemporary home with numerous inside corners in the foundation This
indicates a need for more sealing of cracks after the slab cures because
typically cracks form from an inside corner and radiate toward the center
of the slab. Bach small square in the interior of the foundation
indicates a concrete "pad" upon which lally columns and other structural
supports are placed. The location of each of these pads dictates, to some
extent, the placement of sub-slab piping networks.
A careful review of the lighting schedule showed that extensive use
of recessed lights was planned. Each of these recessed fixtures is a
potential thermal bypass which would allow the movement of air from the
room below to the area above the fixture. Because of the extensive use of
recessed fixtures, combined with the presence of vaulted ceilings, the
decision was made not to address each individual thermal bypass. But
instead, more emphasis would be placed on the sub-slab piping network and
establishment of a negative pressure field.
The materials schedule for the foundation plan indicated that the
use of processed gravel was planned for the sub-slab fill material (95%
sand) This indicated that the installation of a sub-slab piping network
would be necessary in order to provide adequate sub-slab permeability.
After discussing possible locations of the verticle stack with the
huilder a decision was made to locate the stack in a double-wide wall to
b* used'for plumbing. This allowed locating the stack near the center of
the house where there would be adequate warmth to induce a stack effect in
the pipe.
HOUSE B BUILDING PLAN
As can be seen in Figure 2., House B is basically a rectangle with a
minimum of irregularities in the foundation. As with House A, the
lighting schedule for House B indicated extensive use of recessed light
fixtures, causing numerous thermal bypasses. In addition, there were
several large rooms on the first floor which were to have vaulted
ceilings, precluding the effective blocking of thermal, bypasses. Here
again the decision was made to concentrate on the use of pressure
manipulation in the verticle stack and sub-slab area to impede radon
entry in the structure.
-------
Sub-Slab Piping
Figure 2. House B Foundation and Sub-Slab Piping Network
The materials list for the foundation plan indicated the use of
crushed stone as sub-slab fill material. Due to the intended use of
crushed stone fill, no piping network was planned. Only the use of a pipe
stub inserted into the fill material would be necessary to ensure the
negative pressure developed in the verticle stack would be transmitted to
the sub-slab area.
After discussing the placement of the verticle stack with the
builder, it was decided that the most appropriate location of the stack
would be rising within the chimney chase. Although not a typical
location, the local Building Official authorized this location since all
flues rising within the chase were "zero clearance" type flues which would
prevent excessive heat buildup in the chase.
-------
mitigation strategies
The new construction strategies used included provision of sub-slab
permeability during construction, prevention of radon entry through the
usfofbarriers to radon movement from the soil into the structure, and
?he installation of a passive stack vent to <^^elop^fferential pressures
between the basement of the residence and the sub-slab fill material.
d in the number and amount of thermal bypasses, as
rpr-nmmended bv EPA was not used. In both cases, the residences had too
many^hermai bypasses to faci 1 itate cost effectively dealing with the
treatment of eSh bypass source. Rather than attempt to i
thermal bypass, more emphasis was placed on prevention of radon entry
through establishment of sub-slab permeability and the miticulous use of
sub-slab vapor barriers and entry route sealants.
PROVISION OF SUB-SLAB PERMEABILITY
™ * ^ision °f sub-slab permeability is perhaps the most influential
cost of the overall system. The type of sub-slab fill which ig £f,\
determine the necessary actions required to establish adequate
permeability in the sub-slab fill material. In Connectic^ it is m ^
common to use "processed" or "bank-run" gravel as fill mat^r^
S'sto'nT WMCh lndlCate flU materUl WhlGh 15 ~"teT95% s^Tand
technique^are f^TmaTTl
although very desirable, is not a common practice in CoInSJJ^^I '
o£ the increase In construction cost. A £re coLo? ^
installation of a sub-slab piping network much Hk*» a jr.j
into a bed of crushed stone beneath the slaT The g* system'
the use of mat-type material because tte eSense of iST"? is
encourages resident!*! builders to seek less expensive alSm«lies.
When using the sub-slab piping network t-n . .
significant amount of labor can be saved through proper 5J»±n?
piping system can be installed during the instlllati™ of
material itself, all that may be required is the actual asSmhfi ^
layout of the network. However, installation nf *¦* assembly and
after the fill material has been installed win ne^ork at sometime
piping system be assembled, but the fin material mLthl requir® Jhat 1116
piping network installed, covered with fin materia? ^ excavated, the
fill material must be removedefrom the si^ material- then the excess
-------
House A
Since the building plans for House A indicated the use of processed
gravel for fill material, the use of a piping network was required to
ensure adequate sub-slab permeability. Figure 1. shows the arrangement of
the piping system under the slab. In this house the piping network was
actually installed by the foundation workers at the same time the fill
material was installed. This provided a very cost effective provision of
sub-slab permeability.
House B
The building plan specifications for House B indicated the use of
crushed stone as the sub-slab fill material. However when the time came
to install the fill, the builder used processed gravel (95% sand) due to
the lack of available craushed stone. This became apparant after the fill
material had been installed and compacted, creating a permeability
problem. Modifications to the mitigation strategy had to be made; a
piping network was designed and then subsequently installed. Since this
house was being constructed during the winter, the fill material quickly
froze and required the use of picks and adzes to excavate for the piping
system.
CREATING BARRIERS TO RADON ENTRY
The creation of barriers to radon entry for both houses was
accomplished in two steps. After the fill material and piping networks
were installed, a continuous layer of cross laminated plastic sheeting
(Radon Barrier) was installed. The sheeting was layed out on top of the
fill material, then sealed around the foundation with a continuous bead of
polyurethane caulk. Where layers of the plastic sheeting were overlapped,
another continuous bead of caulk was used as glue for the two sections of
sheeting.
Once the slabs had been poured and cured all slab-to-foundation,
control joints, utility penetrations, and settling/stress cracks appearing
in the slab were sealed. The sealing was accomplished by first enlarging
the existing cracks, thoroughly cleaning the opened crack, applying a bead
of sealant, then tooling the sealant into place. This technique digresses
from the EPA recommendations in that no binding agent is applied to the
crack prior to application of the sealant. From experience we have found
that polyurethane sealant will bond well to clean, fresh concrete as long
as all dust and debris is removed prior to application of the sealant.
-------
CONTROL OF DIFFERENTIAL PRESSURE
The control of differential pressures was accomplished primarily by
use of the stack effect to induce a negative pressure in the sub-slab fill
material. The development and communication of the negative pressures
developed by the stack effect was accomplished through the installation of
a "vent stack". This stack uses the tendency of warm air rising in order
to develop a negative pressure field in the sub-slab material. In order
to be most efficient, the verticle vent stack should have the fewest
possible restrictions to air flow.
In both structures, the vent stack was able to run vertically for
approximately 30 feet with no bends. Two 90 degree bends and two 45
degree bends were required in the basement areas to connect the stack to
the sub slab piping network. Through the use of four inch PVC pipe these
bends provided minimal resistance to the air flows typical in a passive
stack configuration.
SYSTEM INSTALLATION
Unlike retrofit applications where the entire system is typically
installed in less than one day, the use of new construction techniques
requires periodic involvement over a long period of time. In the case of
House A, the construction period lasted over six months. In the case of
House B, the construction of the residence took over 14 months. The
economical use of time on site, as well as a close communicative
relationship with the builder will save countless hours of on-site time
and expenses during the construction of the structure. Construction
schedules change on a daily, and sometimes hourly, basis.
The actual implementation of the mitigation strategy can be divided
into four distinct phases; sub-slab preparation, slab pour, application of
sealants, and finally the installation of the vent stack itself. Not
every construction project will require these phases to be accomplished at
different times. In the case of House A, the slab was poured as the
laborers were completing the piping system. Whereas in House B, the slab
was poured four months after the installation of the piping system and
sub-slab fill material.
-------
SYSTEM PERFORMANCE
The performance of the installed systems was verified through the
use of various radon measurements, as well as, periodic differential
pressure measurements. The radon measurements included short-term
screening measurements and long term measurements. Differential pressure
measurements were made once per month after the initial installation of
the vent stack.
RADON MEASUREMENTS
Radon measurements began with short term measurements using
activated charcoal canisters. Initial radon measurements were not made
until the structure was under the interior finishing phases of
construction. This ensured that all windows and doors had been installed
and sealed, and the heating system was in operation. In the case of House
A, where construction was completed in the summer, another short term
measurement was conducted during the heating season.
In addition to the short term measurements, long term radon
measurements were made using alpha-track devices to determine long term
effectiveness of the installed systems. Intentions are to conduct further
long term measurements over the next few years to determine the on-going
effectiveness of the techniques used.
Table 1. shows the results of the radon measurements made in both
structures.
First S
Measi
Month
Screening
jrement
Result
Second S
Measur
Month
Screening
¦ement
Result
Long Term
Measurement
House A
J U N
< 0.5
FEB
1. 9
0 . 7
House B
DEC
1. 2
FEB
1.6
in progress
Table 1. New Construction Radon Measurements (pCi/1 air)
-------
DIFFERENTIAL PRESSURE MEASUREMENTS
Due to limitations in the ability to accumulate continuous long term
data, the differential pressure measurements were made at periodic times
in each structure. Measurement was made of the pressure differences
between the basement of the structure and where the piping system
penetrates the basement slab. No data was taken regarding the environ-
mental conditions present at the time of the measurements. Although
representative of relative operating pressures, the data does not
represent average differential pressure maintained by the stack pipe.
Table 2 shows the differential pressure measurements made in each
structure.
House A
House B
Month
Press.
Month
Press.
JUN
0.04
OCT
0.12
JUL
0.03
NOV
0.03
SEP
0.01
DEC
0 . 05
NOV
0.03
JAN
0.04
JAN
0 . 02
FEB
0 . 09
FEB
0.04
Table 2. Differential Pressure Measurements (inches H20)
PROJECT COSTS
The costs associated with each phase of the new construction project
for these structure is divided into three categories; sub-slab piping
installation, sealing, and stack pipe installation. The total cost for
each project is also reported. Although the total cost of each project
-------
is in excess of the average cost to provide radon mitigation services in a
comparable existing structure, the long-term cost savings due to energy
loss/consumption cam be substantial. In addition, the new construction
systems are virtually "invisible" and become an integrated part of the
structure. This is unlike retrofit mitigation systems which are sometimes
attached directly to the exterior of the structure.
Table 3 provides a breakdown of the costs associated with both
projects.
Sub-Slab
Piping
P r eve n ting
Entry
Stack Vent
Installation
Total Project
Cost
House A
$ 450
$ 520
$ 645
$ 1,615
House B
$ 967
$ 465
$ 450
$ 1,882
Table 3. New Construction Project Cost
CONCLUSION
The ability to implement cost effective radon resistance into
residential new construction is certainly attainable as evidenced in the
two projects outlined in this paper. Through the use of EPA recommended
new construction techniques and judicious use of on-site time, passive
radon reduction strategies can be implemented during new construction that
provide the home owner with significant long term cost savings.
More research needs to be conducted to quanitify the design
parameters involved with the selection and location of the vent stack. In
addition, more data needs to be collected concerning the relationship
between environmental conditions and the development of sub-slab pressure
differentials during the use of passive stack vent systems..
The work described in this paper was not funded by the U.S. Environmental
Protection Agency and therefore the contents do not necessarily reflect
the views of the Agency and no official endorsement should be inferred.
-------
REFERENCES
1. Saum, D. and Osborne, M. Radon mitigation performance of passive
stacks in residential new construction. Ins Proceedings of the 1990
International Symposium on Radon and Radon Reduction Technology.
U.S. EPA, Washington, DC, 1990.
2. Osborne, H. Radon-Resistant Residential New Construction, U.S. EPA,
Washington, DC.
3. Murane, D. Hodel standards and techniques for controlling radon
levels within new buildings. In« Proceedings of the 1990
International Symposium on Radon and Radon Reduction Technology.
U.S. EPA, Washington, DC, 1990.
4. EPA - Connecticut Radon Survey Report. Connecticut Department of
Health Services, 1987.
5. Siniscalchi, A., Rothney, L., Toal, B., Thomas, M., Brown, D., van
der Werff, M., and Dupuy, C. Radon exposure in Connecticut!
Analysis of three statewide surveys of nearly one percent of single
family homes. In« Proceedings of the 1990 International Symposium
on Radon and Radon Reduction Technology. U.S. EPA, Washington, DC,
1990.
6. Popenoe, P. Aeroradioactivity and generalized geologic maps of
parts of New York, Connecticut, Rhode Island and Massachusetts.
Geophysical Investigations Map GP-359, U.S. Geological Survey,
Washington, DC, 1966.
-------
PRELIMINARY RESULTS OF HVAC SYSTEM MODIFICATIONS TO
CONTROL INDOOR RADON CONCENTRATIONS
by : Terry Brennan
Michael Clarkin
Camroden Associates
RD#1, Box 222
Oriskany, NY 13424
Timothy M. Dyess
U.S. EPA, AEERL
Research Triangle Park, NC 27711
William Brodhead
Buffalo Homes
Riegelsville, PA 18077
ABSTRACT
Designing and building houses that control radon in the course
of their normal operation is a desirable goal. A project was
undertaken by the Environmental Protection Agency to assess the
feasibility of modifying the heating, ventilating, and air
conditioning (HVAC) system in a newly constructed tract house, so
that radon entry is prevented, the risk of moisture condensing in
the building shell is reduced, and minimum ventilation
recommendations are met.
A house has been selected, and the HVAC system has been
modified to slightly pressurize the basement while slightly
depressurizing the upper floors. Basement and first floor radon
concentrations, and first floor and basement to outdoor air
pressure differentials have been monitored.
The initial results from one cooling season show that this
method can be as effective as active soil depressurization at
controlling indoor radon levels, with comparable power consumption.
This paper has been reviewed in accordance with the U. S.
EPA's peer and administrative review policies and approved for
presentation and publication.
TECHNICAL APPROACH
The purpose of this work was to evaluate whether a typical
residential furnace unit (air handler) could be easily modified to
pressurize the basement of a tract house to prevent the entry of
radon-laden soil gas. In order to accomplish this goal, the air
pressure relationships between the upper floors and the basement,
and each of those zones and the outdoor air, must be controlled.
This is accomplished by using the air handler of the central
heating and cooling plant, and the existing conditioned air
-------
^ x.- +-o nressurize the basement and slightly
^e^per'^o^r The basic idea is illustrated in
Figure 1.
The house chosen for the study is located in a subdivision in
the Allentown, Pennsylvania, area. It is a two story colonial house
the AJ-ientown, »n but the living room. The living room is
oi a slabSeonn-grade. The house, when originally constructed, was
E»ni- w?th the knowledge that other houses in the area contained
indoor radon concentrations. The builder therefore
high indoor radon resistant techniques during its
construction During construction, attention was paid to building
a foundation that prevented soil air from entering. This effort
included poured concrete walls and floor, all concrete joints
sealed with caulk, and a polyethylene vapor barrier under the slab.
? An active soil depressurization system was installed
" thf biiliing with a 4 in.Aayer of DOT #2 stone, an interior
perimeter loop of 4 in. drain pipe, a 4 in. PVC pipe routed through
the building and out the roof, and an in-line centrifugal blower.
Air pressure relationships were measured between the inside
and outside of the building, and between zones within the building.
WAC system airflows and power consumption were measured for the
thrceHVAC blower operating speeds. These were quite close to the
specifications. Investigations of the extent of air
ipakaae in what appeared to be carefully installed ductwork,
that the ductwork was still surprisingly leaky. This was
particularly tr\^ of the return system. An indication of the
effects of this leakage was that, when the air handler was operated
on low speed, several pascals negative pressure was produced in the
relative to outdoor air. Extensive sealing of the return
til JKctwrk wm required to bring the basement into neutral
pressure with the outdoor air. See the later section on air leakage
patterns for details-
The air handler that heats and cools the first floor of the
hnn(!P is located in the basement. All supply and return ductwork is
also located in the basement. The basement was pressurized simply
vZ-oillino the leaks in the return air ductwork and cutting an
oLnint* in the supply ductwork main trunk. This modification
in the pressurization of the basement, with respect to
iJrfinr-s of 4 Pa. This modification also resulted in greater
infiltration in the upstairs living area to make up the air lost
through basement.
~Readers more familiar with metric units may use the factors at the
end of this paper to convert to that system.
-------
AIR HANDLER DESCRIPTION AND OPERATING CHARACTERISTICS
Effects of HVAC system operation on radon levels
The effects of system operation on indoor radon were studied
by monitoring radon continuously in the basement and the kitchen
with the air handler off, with the air handler on low speed
continuously, and with the air handler on high speed only when
cooling was called for. The results are summarized in Table 1, and
illustrated in Figures 2, 3, and 4. Figure 2 shows that, while the
air handler is on, there is about a 4 Pa positive air pressure
difference between the basement and outdoor air, and the indoor
radon averages 1.2 pCi/L in the basement and kitchen (a sign of
good mixing with the air handler on) . This level compares well with
the active soil depressurization results from the previous year of
1.1 pCi/L[l]. However, with the air handler off, the basement air
pressure quickly drops, and there are radon spikes each time the
basement goes negative relative to outdoor air. This pattern has
been observed in many buildings before[2],[3],[4]. The average
radon concentration with the system off is around 14 pCi/L in the
basement and 2 pCi/L in the kitchen. Later system off measurements
in July (see Table 1) show the same levels in the basement, and a
slightly higher kitchen average of 3.3 pCi/L. Figure 3 shows
typical data for the system operating continuously, on a scale that
allows better detail. The results are the same as the June
measurements in Figure 2, and it is clear that radon is being
controlled in both the upstairs and basement, with 50% and 90%
reductions, respectively. Figure 4 shows a detail of system
performance when the air handler runs only in response to cooling
demand. While the radon is lowered by a factor of around 3, it is
still above the action guideline of 4 pCi/L, averaging 7 pCi/L for
the cooling operation test period. It is also clear from the
pressure data that the fractional on time of the air handler was
large during the test period. The radon levels in this building
will be very sensitive to fractional on time.
Description
The house is heated and cooled using a York heat pump with a
three-speed air handler. Table 2 lists the design airflows for
this unit at low, medium and high speeds for two static pressures.
Airflows through ductwork with the air handler on low speed
Airflows were measured at the supply and return grills, and in
the main trunk of the supply ductwork, with the intentional opening
used to pressurize the basement open and closed. The results of
these measurements are given in Tables 3 and 4. The total measured
supply, measured in the supply trunk close to the air handler, was
952 ± 90 cfm. This compares well with the manufacturer's
specifications of 1160 to 1185 cfm for the air handler on low
speed. From the measurements made, the leakage through the supply
-------
ductwork was calculated to be around 230 cfm, and through the
return ductwork was around 450 cfm. This means that, with the unit
as installed, the basement was under negative pressure of several
pascals whenever the air handler was on. The supply ductwork was
foil faced ductboard. The return ductwork was made by sealing
ductboard to the bottom of floor joists. It is thought that the
excessive leakage in the return system, to a great extent, is due
to leakage in the floor and wall components that form the return
ductwork. In fact, careful sealing of the return system reduced the
return air duct leakage to about 200 cfm.
The results of measurements and calculations with the ductwork
sealed, and the basement pressurization opening open and closed are
presented on Tables 3 and 4.
Sealing the return ductwork
The return system in the basement was carefully sealed using
duct tape and caulk. The indoor-outdoor pressure differential was
monitored before and after the sealing. With the air handler
running and the pressure opening closed, the basement was several
pascals negative before the sealing, and neutral after. Sealing the
return air ducts reduced leakage to approximately 200 cfm. At this
point supply leakage, excluding the intentional opening used to
pressurize the basement, approximately equaled return leakage, it
is estimated that the additional cost of sealing ductwork and
making wiring modifications to the air handler is $200 to $300.
AIR LEAKAGE PATTERNS CAUSED BY OPERATION OF THE BASEMENT
PRESSURIZATION MODE
In order to understand the dynamics of operating the air
handler to pressurize the basement and slightly depressurize the
upstairs, interzonal and indoor to outdoor pressure differentials,
and the leakage areas of interest were measured. From these data,
the amount of outdoor air drawn into the building could be
estimated. This can then be compared to the ASHRAE ventilation
guidelines [5] and the estimated stack effect infiltration that
would occur in this house normally.
Operating the air handler induces a 4 Pa pressure differential
between the basement air and the outdoor air and a 4.5 Pa pressure
differential between the upstairs and the basement. This implies a
0.5 Pa pressure differential between the upstairs air and the
outdoors.
By combining this air pressure distribution data with measured
building leakage area data, airflows between the two zones and
outdoors can be estimated. The leakage areas were measured using a
fan door technique, involving the use of two fan doors.
Measurements were made on each zone individually, and then
simultaneously. Details of the method are presented elsewhere [6],
The results of the measurements and analysis are found on Figure 5.
-------
ENERGY AND VENTILATION ISSUES
Changing the air pressure relationships in a building to
control soil gas entry will have an impact on other dynamics in the
building. Specifically it is expected that this will impact on the
ventilation pattern, the energy costs associated with ventilation,
and the risk of moisture condensation in the building shell. No
data are available to judge the effects of moisture in the building
shell. However, the data collected can be used to estimate the
impact on the amount and pattern of infiltrating air. This is
accomplished by first estimating the amount of air that would flow
through the building as a result of ordinary stack effect and then
comparing to the airflows induced by pressurizing the basement
The results of these estimates can be used to calculate the
power consumption for controlling radon with basement
pressurization and with active soil depressurization.
Impact of basement pressurization on infiltration
A fan door test of the entire building shell revealed that it
has 5 air changes per hour (ACH) at a 50 Pa pressure differential.
This is two to three times tighter than the average house built
between 1945 and 1980, but is more typical of houses built in the
northeast United States since 1980. This translates to about 0.25
ACH under natural conditions.
The infiltration due to stack effect alone has been calculated
using four air infiltration models: the Lawrence Berkeley
Laboratory model, the Kronval model, the Shaw model, and a modified
Shaw model [7]. The results of these four models are plotted on
Figure 6. Excluding the Shaw model, the mean values range from 0.13
to 0.17 ACH. This corresponds well to the 0.25 ACH combined wind
and stack estimate made from dividing the ACH at 50 Pa by 20 [7].
By using the monthly ACH data the average volume of airflow through
the building operating under average stack conditions can be
calculated. This has been done in Table 5.
The amount of outdoor air drawn through the building by
operating the air handler in the basement pressurization mode was
estimated to be between 53 and 87 cfm. If any, there should be only
a small energy penalty added by operating in this manner, amounting
at most to an additional 35 cfm of outdoor air. This would add 3.3
x 106 Btu to the normally operating stack effect load of 4.6 x 106
Btu. This amounts to around $33 of oil at $l.l0/gal. or $79 of
electric resistance heat at $0.08/kW-hr. It would actually be less
than this because of the superior efficiency of the heat pump in
the swing seasons [coefficient of performance (COP) of 2.2].
However, it is unlikely that this will be the case because the
direction of airflow is opposite that of the stack effect. The
power of the fan will be competing with the power of the stack
effect. They should just about cancel each other out in the coldest
parts of the year resulting in lowered infiltration for the
building during the winter months. This, however, is not an
accurate model because the system is acting a lot more like two
-------
7ones with the air handler powering the exchange, rather
than with the stack effect powering it. A distributed resistance
simulation could approximate the final situation.
It is likely that the infiltration due to stack effect will
about equal the infiltration due to pressurizing the basement. The
difference is that, with basement pressurization, the infiltration
will be greatest in the summer and least in the winter the
win we wit-hpr will provide an average of about
4 0Pcfm This8isC over half the recommended ASHRAE guideline of 15
cfm/person and the ASHRAE recommended ventilation rate of 0.35 ACH
for residential buildings [5].
POWER CONSUMPTION COMPARISON OF NORMAL PRES^IZ^THE
SUB-SLAB SUCTION VS. USING THE HVAC ON LOW SPEED TO PRESSURIZE THE
BASEMENT
The total power consumption of radon control and operation of
the heat pump air handler for soil depressurization and basement
pressurization must be compared.
The amount of electricity used to power the soil
depressurization system is 90 W continuously for a year. This
amounts to 788 U. Jh.2^6 wTor* 3^
Srf ylar)P.erThis°gives a total power consumption of 1459 KWh/yr for
the active soil depressurization system.
The amount of power needed to pressurize the basement for the
vear is estimated as follows. The amount of power used to operate
the ai? handler on high speed for normal operation and low speed
Tel the remaining time i/l673 kwh/yr (174 W for 5760 hr on low
speed and 249 W for 3000 hr on high speed).
It is estimated that basement pressurization will use 214
kwh/yf mo?e Sa£ soil depressurization or about $18 a year for
electricity at $0.085/kWh.
CONCLUSIONS
neinn the interaction of the air handler,
The basic ideai tio^. svstem, and the building shell to
SS&M p«ssur\ScSSS
??^rSr°aSn^
depressurization. ^
°r "hLhe? the'risk of^ioisture condensation in the building shell
has been reduced* Further research will be required to answer these
questions.
romiired to modify the HVAC system was not great.
The eff°rt "2SieBentB and understanding it took, while
iESEtag only trivial physics, are not part of the ordinary
-------
experience or training of builders, mechanical contractors, or
mechanical engineers. Further complicating this procedure is the
fact that the work needed to make the modifications cuts across
traditional trade jurisdictions. It is likely that most of the work
falls into the jurisdiction of the mechanical contractor. However,
general contractors must be able to request the work and judge the
performance.
REFERENCES
1. Brennan, T., M. Clarkin, M.C. Osborne, W.P. Brodhead,
Evaluation of Radon Resistant New Construction Techniques.
Presented at the 1990 International Symposium on Radon and
Radon Reduction Technology. 1990. Atlanta: EPA.
2. Hubbard, L., B. Bolker, R. Socolow, D. Dickerhoff, R. Mosley,
Radon Dynamics in a House Heated Alternately by Forced Air and
by Electric Resistance. In Proceedings: The 1988 Symposium on
Radon and Radon Reduction Technology, Volume 1, EPA-600/9-89-
006a (NTIS PB89-167480), March 1989.
3. Michaels, L. , T. Brennan, A. Viner, A. Mattes, W. Turner,
Development and Demonstration of Indoor Radon Reduction
Measures for 10 Homes in Clinton, New Jersey, EPA-600/8-87-027
(NTIS PB87-215356), July 1987.
4. Turk, B., R. Prill, W. Fisk, D. Grimsrud, B. Moed, R. Sextro,
Radon and Remedial Action in Spokane River Valley Homes,
Volume 1 : Experimental Design and Data Analysis. 1987,
Lawrence Berkeley Laboratory.
5. ASHRAE Standard 62-1989. Ventilation for Acceptable Indoor
Air Quality. ASHRAE, Atlanta, GA, 1989.
6. Brennan, T., Fan Door Testing on Crawlspace Buildings. Air
Change Rates and Airtightness in Buildings. 1989.
Philadelphia: ASTM.
7. Nitschke, I., Indoor Air Quality, Infiltration and Ventilation
in Residential Buildings. 1985, NYSERDA-Niagara Mohawk.
-------
CONVERSION FACTORS
Readers more familiar with metric units may use the following
to convert to that system.
Non-metric Multiplied bv Yields Metric
Btu 1.055 kJ
cfm 0.00047 m3/s
gal. 0.0038 m3
in. 2.54 cm
in. WC 249 Pa
in.2 0.00065 m2
-------
TABLE 1 EFFECTS OF AIR HANDLER OPERATION ON INDOOR RADON
Date
(mm/dd/yy)
•
Location
Average
Rn (pCi/L)
Average
aP (Pa)
HVAC
Status
06/07-15/90
06/07-15/90
basement
1st floor
1.2 ± 0.3
1.1 ± 0.4
4.0
± 1.3
on
on
06/16/90-07/04/90
06/16/90-07/04/90
basement
1st floor
14.3 ± 5.1
2.1 ± 1.4
0.8
± 1.8
off
off
07/07-23/90
07/07-23/90
basement
1st floor
14.2*
3.3 ± 1.7
0.5
± 1.6
off
off
07/25/90-08/05/90
07/25/90-08/05/90
basement
1st floor
1.4 ± 0.3
1.2 ± 0.4
4.2
± 0.8
on
on
08/14/90-09/11/90
08/14/90-09/11/90
basement
1st floor
1.4 ± 0.3
1.2 ± 0.4
4.2
± 0.8
cooling
moling
* This measurement taken with a Honeywell At-ease Monitor.
TABLE 2 MANUFACTURER'S SPECIFICATIONS FOR FAN UNIT
Speed Airflow § 0.2 in. WC Airflow® 0.3 in. WC
(cfm) (cfm)
high 1625 1550
medium 1355 1310
low 1185 1160
TABLE 3 OPERATING CHARACTERISTICS WITH BASEMENT PRESSURIZATION
Total measured supply at diffusers = 567 ± 60 cfm
Total measured supply = 952 ± 90 cfm
Total supply leakage* = 385 ± 40 cfm
(including flow through the intentional opening pressurizing the
basement)
Total measured return = 496 ± 50 cfm
Total return ductwork leakage* « 456 ± 46 cfm
* calculated values
-------
TABLE 4 OPERATING CHARACTERISTICS WITHOUT BASEMENT PRESSURIZATION
Total measured supply at diffusers = 719 ±72 cfm
Total supply ductwork leakage* = 232 ± 23 cfm
Intentional opening to pressurize the basement* = 153 ± 15 cfm
* calculated values
TABLE 5 STACK EFFECT AIRFLOWS FOR AVERAGE TEMPERATURES
Month
Stack
(cfm)
Jan
73
Feb
71
Mar
64
Apr
51
May
36
Jun
0
Jul
0
Aug
0
Sep
25
Oct
28
Nov
60
Dec
71
-------
ASD
Stack Capped for Tests
Incoming Air
Reduces Risk of
Condensation
Fan for ASD
(Active Soil Depressurization
(Not in use for this test)
Kitchen
Living Area
Return Air
Supply
Air
Ductwork
Sealed
Supply
Air to
Basement
Heat
Pump
Air
Handler
Outgoing
Air
Prevents
Soil Air
Entry
tail i -.v'A •.-v«
mmm
Figure l. Illustration showing the use of the heating, ventilating
and air conditioning system to control radon entry, minimize the
risk of condensation in the upper floors, and provide recommended
ventilation rates.
-------
25
20
1 5
10
HVAC ON
HVAC off
'w"A-
- 5 "I 1 1 I 1 I I i r
6/7/90 6/11/90 6/15/90 6/19/90 6/23/90 6/27/90 7/1/90 7/5/90 7/9/90
Basement &P
......
Basement Radon
-•••A-
Kitchen Radon
Figure 2. Radon levels and differential pressures with air handler
on and off.
-------
V
4
/
7/25/90
7/29/90
8/2/90
8/6/90
Basement aP
¦*— Basement Radon
-A— Kitchen Radon
Figure 3. Radon levels and differential pressures with the air
handler on continuously
-------
0
B/15/90
8/16/90
8/17/90
8/18/90
_e_ Basement Ap
-m— Basement Radon
Kitchen Radon
Figure 4. Radon levels and differential pressures with the air handler
operating in normal cooling mode
-------
Qout
Qoutsid
Qreturn
Ofloor
Measured Effective Leakage Area (ELA)
ELA House less floor = 69 sq in.
ELA Basement less floor
40 sq in.
ELA floor « 35 sq in.
Calculated directly from
pressure - ELA data using
airflow through a sharp
edged orifice
Qoutside should equal
Qout. Although 53 does
not equal 87 the
difference is within the
experimental error of the
measurements.
Qfloor = 83 cfm ± 25 cfm
Qout = 87 cfm
Qoutside = 53 cfm ± 20 cfm
Assuming that the
return leaks equal the
supply leaks
Qbase = Qoutside + Qfloor
Resulting in Qbase
estimates of
Qbase
136 - 170 cfm
This compares well with Qbase estimated from
the ductwork airflow measurements of 138 cfm.
Figure 5. Airflows and pressure patterns with the air handler on
low speed
-------
0.4
-6 -—i- L—4-
-*r:
x
o
<,
®
c
o
<
ifc
LU
je
to
55
e
o
C
o
13
±S
0.3
o Kronval
—a- Shaw (comb.)
Modified Shaw
---- LBL
0.2
0.1
¦0.1 t
1
5 7
Month
1 1
Figure 6. Estimated airflows through the test house resulting from
stack effect alone. Four models have been used. The stack effect and
the air handler produce countervailing pressure fields, to some extent
canceling some of the effect of each.
-------
VIIIP-3
RADON CONTROL PROFESSIONALS, INC.
11920 Fieldthorn Ct.
Reston, Va. 22094
(703) 471-9459
INSURED
LICENSED
EPA TRAINED
CORRELATION OF SOIL RADON AVAILABILITY NUMBER WITH INDOOR RADON
AND GEOLOGY IN VIRGINIA AND MARYLAND
Soil radon availability number measurements by RCP have yielded
correlations with both indoor radon levels and various geologic units.
Radon availability number is a function of soil radon concentration,
permeability, and diffusion rate. The equipment consists of a Pylon
radon monitor vith attached Lucas cell and RCP-developed soil probe.
Determined radon availability numbers plotted against indoor
radon levels revealed two distinct populations separating buildings
vith basements from those without basements or with other construction
factors.
Thus, soil tests are being used with favorable success to predict
the potential for elevated indoor radon levels and enable the design
of pre-construction mitigation systems with the correct magnitude and
location of ventilation points.
Stephen T. Hall
Radon Control Professionals, Inc.
-------
200
180
160
140
120
100
•0
60
40
20
CORRELATION BETWEEN SOIL TEST
RESULTS AND INDOOR RADON
y with mitigatingJactors
10 20 30 40 50 60 70 SO
RADON AVAILABILITY NUMBER, KBq/m2
-------
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Whltter Woods Elementary School - Sub-slab radon levelo
delineating a N60°w fracture trend.
-------
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delineating a N60°tf fracture trend.
-------
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