United States EPA-600/R-93-225
Environmental Protection
Agencv December 1993
&EPA Research and
Development
CASE STUDIES OF
RADON REDUCTION RESEARCH
IN 13 SCHOOL BUILDINGS
Prepared for
Office of Radiation and Indoor Air
Prepared by
Air and Energy Engineering Research
Laboratory
Research Triangle Park NC 27711
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before comple
1, REPORT NO,
EPA-600/R-93-22 5
4. TITLE AND SUBTITLE
Case Studies of Radon Reduction Research in 13
School Buildings
5. REPORT DATE
December 1993
6. PERFORMING ORGANIZATION CODE
IIIIIIIIIIIIIIIIIIII
PB94-130010
7. AUTHOR1S}
Bobby E.
Pyle and Ashley D. Williamson
8. PERFORMING ORGANIZATION REPORT NO.
SRI ENV- 92-766- 7400.10
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Southern Research Institute
P. C. Box 55305
Birmingham, Alabama 35255-5305
10. PROGRAM ELEMENT NO.
11. CONTRACT/ GRAN" NO
EPA Cooperative Agreement
CR818413
12, SPONSORING AGENCY NAME AND ADORESS
13. TYPE OF REPORT AND PERIOD COVERED
EPA, Office of Research and Development
Air and Energy Engineering Research Laboratory
Research Triangle Park, NC 27711
Final; 3/92-9/93
14. SPONSORING AGENCY CODE
EPA/600/13
is. supplementary notes project officer is Kelly W,
7717.
Leovic, Mail Drop 54, 919/541-
is. abstract Yhe report details 13 case studies covering radon mitigation research in
school buildings from 1990 to 1992. The 13 schools are in Colorado, Maine, Minneso-
ta, Ohio, South Dakota, Tennessee, and the State of Washington. Diagnostics were
carried out in all of these schools, and suggested mitigation plans were developed
for each, based on the diagnostic measurements. Mitigation systems were installed
in 5 of the 13 schools as part of the project. The major objective of these research
projects was to better understand the conditions under which heating, ventilating, and
air-conditioning (HVAC) systems in existing school buildings could be used for effec-
tive radon reduction. Criteria used to evaluate system effectiveness included: radon
reduction; long-term reliability of operation; installation, maintenance, and operating
costs; and impact on the indoor air quality in the school. An additional objective,
studied in three of the schools, was to compare the effectiveness of HVAC system
control of radon with active subslab depressurization control in the same building.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.identifiers/open ended terms
c. COSAT) Field/Group
Pollution
Radon
Research
School Buildings
Measurement
Ventilation
Pollution Control
Stationary Sources
Indoor Air Quality
13 B
07B
14F
13M, C5I
14 G
13 A
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY Cu.ASS (This Report}
Unclassified
21. NO. OF PAGES
230
20. SECURITY CLASS (This page)
Unclassified
EPA Form 2220-1 (9-73)
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EPA REVIEW NOTICE
This report has been reviewed by the U.S. Environmental Protection Agency, and
approved for publication. Approval does not signify thai the contents necessarily
reflect the views and policy of the Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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Illllll 111 llllllllllllli
PB94-130010
EPA-600/R-93-225
December 1993
CASE STUDIES OF RADON REDUCTION RESEARCH
IN 13 SCHOOL BUILDINGS
FINAL REPORT
Prepared by:
Bobby E. Pyle and Ashley D. Williamson
Southern Research Institute
2000 Ninth Avenue South
P. O. Box 55305
Birmingham, AL 35255-5305
EPA Cooperative Agreement No. CR-818413
EPA Project Officer
Kelly W. Leovic
Indoor Air Branch
Air and Energy Engineering Research Laboratory
Research Triangle Park, NC 27711
Prepared for
U.S.Environmental Protection Agency
Office of Research and Development
Washington, DC 20460
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ABSTRACT
This report details 13 case studies covering radon mitigation research in
school buildings. The research was conducted by EPA1s Air and Energy Engineering
Research Laboratory's |A£ERL's) Radon Mitigation Branch from 1990 to 1992. The
13 schools are located in Colorado, Maine, Minnesota, Ohio, South Dakota,
Tennessee, and Washington state. Diagnostics were carried out in all of these
schools and suggested mitigation plans were developed for each based on the
diagnostic measurements. Mitigation systems were installed in five of the 13
schools as part of the research project.
The major objective of these research projects was to better understand the
conditions under which heating, ventilating, and air-conditioning (HVACI systems
in existing school buildings could be used for effective radon reduction.
Criteria used to evaluate the system effectiveness included* radon reduction,
long-term reliability of operation; installation, maintenance, and operating
costs; and impact on the indoor air quality in the school. An additional
objective, studied in three of the schools, was to compare the effectiveness of
HVAC system control of radon with active subslab depressurization (ASD) control
in the same building.
ii
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CONTENTS
ABSTRACT ' ii
FIGURES vii
TABLES ........ ... xiii
ACKNOWLEDGEMENTS xv
METRIC CONVERSION FACTORS ' xvi
1. INTRODUCTION 1
1.1 BACKGROUND .......... 1
1.2 OBJECTIVES ¦ . 3
1.3 APPROACH . , 3
2. CONCLUSIONS AND RECOMMENDATIONS* !*!]]]]*.*!!! 4
3. COMMON DIAGNOSTIC MEASUREMENT AND MITIGATION TECHNIQUES 6
3.1 REVIEW OF RADON SCREENING AND CONFIRMATORY
MEASUREMENTS . 6
3.2 REVIEW OF BUILDING PLANS 6
3.3 BUILDING INVESTIGATION . . 7
3.4 HVAC SYSTEM AND PRESSURE DIFFERENTIALS ..... 7
3.5 SUBSLAB PRESSURE FIELD EXTENSION MEASUREMENTS . . 9
3.6 MEASUREMENT OF SUBSLAB RADON LEVELS . 10
3.7 CONTINUOUS MONITORING AND DATALOGGING SYSTEM . , 10
3.8 DEVELOPMENT OF TEST MATRICES 10
3.9 GOOD TECHNIQUES IN ASD MITIGATION SYSTEMS .... 11
4. COLORADO SCHOOLS 12
4.1 BARTON ELEMENTARY SCHOOL 12
4.1.1 Building Description 12
4.1.2 Pre-mitigation Radon Measurements .... 12
4.1.3 Building Investigation ......... 13
4.1.4 HVAC System And Pressure Differentials . 13
4.1.5 Diagnostic Measurements . . . 14
4.1.6 Mitigation Strategy 15
4.1.7 Results of Initial Mitigation System . . 16
4.1.8 Additional Phases of Diagnostics, Mitigation,
Future Plans ..... 17
4.1.9 Estimated Costs 17
4.1.10 Summary ... ......... 17
4.2 PLATTEVILLE ELEMENTARY SCHOOL 17
4.2.1 Building Description 17
4.2.2 Pre-Mitigation Radon Measurements .... 18
4.2.3 Building Investigation ......... 18
4.2.4 HVAC System And Pressure Differentials . 19
4.2.5 Diagnostic Measurements 19
4.2.6 Mitigation Strategy 19
4.2.7 Mitigation System Details ........ 20
4.2.8 Additional Diagnostics and Mitigation . . 21
4.2.9 Estimated Costs 22
4.2.10 Summary 22
iii
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5. MAINE SCHOOLS 23
5.1 SANFORD MIDDLE SCHOOL 23
5.1.1 Building Description 23
5.1.2 Pre-Mitigation Radon Measurements .... 23
5.1.3 Building Investigation ... 23
5.1.4 HVAC System and Pressure Differentials . 23
5.1.5 Diagnostic Measurements ......... 24
5.1.6 Mitigation Strategy ..... 24
5.1.7 Results of Initial Mitigation System . . 24
5.1.8 Summary . 25
5.2 ROSSELL ELEMENTARY SCHOOL 25
5.2.1 Building Description 25
5.2.2 Pre-Mitigation Radon Measurements .... 25
5.2.3 Building Investigation 25
5.2.4 HVAC System 25
5.2.5 Diagnostic Measurements 26
5.2.6 Initial Mitigation Systems 26
5.2.7 Results of Initial Mitigation 26
5.2.8 Additional Diagnostics and Mitigation . . 27
5.2.9 Summary 28
6. MINNESOTA SCHOOL .... ..... 29
6.1 NOKOMIS ELEMENTARY SCHOOL .... 29
6.1.1 Building Description . 29
6.1.2 Pre-Mitigation Radon Measurements .... 29
6.1.3 Building Investigation/HVAC System ... 29
6.1.4 Mitigation Strategy 29
6.1.5 Diagnostic Measurements 30
6.1.6 Results of Diagnostic Measurements ... 31
6.1.7 Summary 32
7. OHIO SCHOOLS 34
7.1 OAKMONT ELEMENTARY SCHOOL 34
7.1.1 Building Description .......... 34
7.1.2 Pre-Mitigation Radon Measurements .... 35
7.1.3 Building Investigation 35
7.1.4 HVAC System and Pressure Differentials . 35
7.1.5 Diagnostic Measurements ......... 36
7.1.6 Mitigation Strategy 37
7.1.7 Effect of Outdoor Air Damper Position on
Radon -- Before Adjustments 37
7.1.8 Effects of Outdoor Air Damper Position on
Radon — After Adjustments ........ 38
7.1.9 Estimated Costs 38
7.1.10 Summary ................. 38
7.2 SULLIVANT ELEMENTARY SCHOOL 39
7.2.1 Building Description .......... 39
7.2.2 Building Investigations 40
7.3 FIFTH AVENUE ELEMENTARY SCHOOL ......... 40
7.3.1 Building Description 40
7.3.2 Pre-Mitigation Radon Measurements .... 40
iv
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7.3.3 Building Investigations ... 40
7.3.4 HVAC System and Pressure Differentials . 40
7.3.5 Diagnostic Measurements ... 41
7.3.6 Mitigation Strategy 41
7.3.7 Mitigation System Details 42
7.3.8 Additional Diagnostics and Mitigation . . 42
7.3.9 Estimated Costs 43
7.4 HUBBARD ELEMENTARY SCHOOL 43
7.4.1 Building Description ..... 43
7.4.2 Pre-Mitigation Radon Measurements .... 43
7.4.3 Building Investigation .... 43
7.4.4 HVAC System and Pressure Differentials , 44
7.4.5 Diagnostic Measurements 44
7.4.6 Mitigation Strategy 44
7.4.7 Summary . 44
8. SOUTH DAKOTA SCHOOL 4 5
8.1 ABRAHAM LINCOLN ELEMENTARY . 45
8.1.1 Building Description 45
8.1.2 Pre-Mitigation Radon Measurements .... 45
8.1.3 Building Investigation 46
8.1.4 Diagnostic Measurements 46
8.1.5 HVAC Systems and Pressure Differentials . 47
8.1.6 Mitigation Strategy 48
8.1.7 Results Of Initial Mitigation System . . 49
8.1.8 Additional Phases of Diagnostics and/or
Mitigation 50
8.1.9 Final Radon Levels ...... 50
8.1.10 Estimated Cost 51
8.1.11 Summary 51
9. TENNESSEE SCHOOL 52
9.1 GLENVIEW ELEMENTARY SCHOOL 52
9.1.1 Building Description 52
9.1.2 Pre-mitigation Radon Measurements .... 52
9.1.3 Building Investigation 52
9.1.4 HVAC System and Pressure Differentials . 53
9.1.5 Diagnostic Measurements ... 53
9.1.6 Mitigation Strategy 53
9.1.7 Results of Initial Mitigation
(Spring/Summer) ..... 54
9.1.8 Results of Initial Mitigation (Winter) 56
9.1.9 Final Radon Levels ..... 57
9.1.10 Estimated Costs 57
9.1.11 Summary 57
10. WASHINGTON STATE SCHOOLS ¦ 59
10.1 LIDGERWOOD ELEMENTARY SCHOOL ... 59
10.1.1 Building Description 59
10.1.2 Pre-Mitigation Radon Measurements ... 59
10.1.3 Building Investigation 59
10.1.4 HVAC System and Pressure Differentials . 60
10.1.5 Diagnostic Measurements 61
v
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10.1.6 Mitigation Strategy . . 62
10.1.7 Estimated Cost 65
10.1.8 Summary and Recommendations ...... 65
10.2 SHERIDAN ELEMENTARY SCHOOL ..... 66
10.2.1 Building Description .... 66
10.2.2 Fre-Mitigation Radon Measurements ... 66
10.2.3 Building Investigation . 66
10.2.4 HVAC System and Pressure Differentials . 66
10.2.5 Diagnostic Measurements 68
10.2.6 Mitigation Strategy ..... 68
10.2.7 Summary and Recommendations 68
11. QUALITY CONTROL AND QUALITY ASSURANCE 69
11.1 INTRODUCTION . 69
11.2 QUALITY ASSURANCE PROJECT PLAN . 69
11.3 CHARCOAL CANISTER MEASUREMENTS 69
11.3.1 Assessment of Precision 69
11.3.2 Assessment of Accuracy . 69
11.3.3 Assessment of Completeness 70
11.4 CONTINUOUS RADON MONITORS ..... 70
11.4.2 Assessment of Accuracy 70
11.5 DIFFERENTIAL PRESSURE MEASUREMENTS . . 70
11.6 CONTINUOUS MONITORING PROCEDURES . . 70
11.7 NON-CONTINUOUS MEASUREMENT PROCEDURES 71
11.8 AUDITS . 71
12. REFERENCES ........ 72
APPENDIX A. Ficures A-l
APPENDIX B. Tables B-l
vi
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FIGURES
Number Page
4.1.1 Floor plan showing additions, room numbers, return air
tunnel, and dimensions at Barton Elementary School. A-2
4.1.2 Floor plan and location of the boiler room at Barton
Elementary School. A-3
4.1.3 Results of January 1990 radon screening measurements
at Barton Elementary School, in pCi/L. A-4
4.1.4 Results of February 1990 radon follow-up measurements
at Barton Elementary School, in pCi/L. A-5
4.1.5 Comparison of the January 1990 and February 1990 radon
measurements at Barton Elementary School (some of the
January tests were not repeated in February). A-6
4.1.6 Floor plan showing the locations of subslab grade
beams and thickened slabs at Barton Elementary
School. A-7
4.1.7 Location of subslab test points used during the
communication and radon profile tests at Barton
Elementary School, radon levels in pCi/L. A-8
4.1.8 Subslab communication test results at Barton
Elementary School (the SP values are the applied
suction pressures). A-9
4.1.9 Effects of opening OA damper upon radon levels at
Barton Elementary. A-1Q
4.1.10 Correlation of the 8 hour average radon levels with
the 8 hour average OA damper positions at Barton
Elementary. A-11
4.1.11 Correlation of the 24 hour average radon levels with
the 24 hour average OA damper positions at Barton
Elementary. A-12
4.1.12 Correlation of the 8 hour average subslab radon levels
with the average OA damper positions at Barton
Elementary. A-13
4.1.13 Correlation of the 24 hour average subslab radon
levels with the average OA damper positions at Barton
Elementary. A-14
4.1.14 Comparison of all radon measurements made at Barton
Elementary School (some tests were not repeated each
time). A-15
4.2.1 Floor plan showing building additions and subslab
footer locations at Platteville Elementary School. A-16
4.2.2 Location of canister numbers for CC measurements in
Platteville Elementary School. A-17
4.2.3 Results of March 1990 radon screening measurements in
Platteville Elementary School, in pCi/L. A-18
4.2.4 Results of August 1990 follow-up radon measurements in
Platteville Elementary School, in pCi/L. A-19
4.2.5 Comparison of the March 1990 and August 1990
measurements at Platteville Elementary School, in
pCi/L. A-20
4.2.6 Locations of suction and test points used in subslab
communication tests and the radon levels under the
slab at Platteville Elementary School, in pCi/L. A-21
VI i
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Figures (Continued)
Number Page
4.2.7 Pressure field extensions from suction point 1 located
in Room 16 at Platteville Elementary School, the SP
values are the applied suction pressure in inches of
water column. A-22
4.2.8 Pressure field extensions from suction point 2 located
in Room 13 at Platteville Elementary School, the SP
values are the applied suction pressure in inches of
water column. A-23
4.2.9 Approximate pressure field extensions measured at
Platteville Elementary School. A-24
4.2.10 Proposed mitigation systems for Platteville Elementary
School. A-25
4.2.11 Subslab suction point details for 4 inch diameter
suction pipe. A-26
4.2.12 Subslab suction point details for 2 inch diameter
suction pipe. A-27
4.2.13 Comparison of the December 1990 cc measurements made
with the HVAC units on and off at Platteville
Elementary, Platteville, CO. A-28
4.2.14 Changes in the radon levels when the HVACs on versus
when off at Platteville Elementary, Platteville, CO. A-29
4.2.15 Comparison of the March 1990 and March 1991
measurements at Platteville Elementary, Platteville,
CO. A-30
5.1.1 Floor plan of the basement rooms of the NW wing of
Sanford Middle School, Sanford, ME. A-31
5.1.2 Location of mitigation system installed and subslab
communication tests results in the NW wing of Sanford
Middle School, Sanford, ME (in.W.C.-fan off/in.W.C.-
fan on). A-32
5.1.3 Location of fan mounted on the roof of Sanford Middle
School, Sanford, ME. A-33
5.1.4 Tentative results of the mitigation system installed
in Sanford Middle School, Sanford, ME. A-34
5.2.1 Plan view of Russell Elementary, Gray, ME. A-35
5.2.2 Correlation of radon level increases with changes in
barometric pressure at Russell Elementary School,
Gray, ME, A-36
5.2.3 ASD performance, for center wing of Russell
Elementary. . A-37
5.2.4 Continuous C02 levels in HRV room at Russell
Elementary, Gray, ME. A-38
6.1.1 Floor plan of Nokomis Elementary School, St. Paul, MN,
showing radon mitigation system locations. A-35
6.1.2 Radon levels during the testing period at Nokomis
Elementary School. A-40
6.1.3 Radon levels during additional testing period at
Nokomis Elementary School (no data for Room 106). A-41
7.1.1 Plan view of Oakmont Elementary School, Columbus,
OH. A-42
Vlll
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Figures (Continued)
Number Page
7.1.2 Location of canister numbers for CC measurements and
foundation walls and footings in Oakmont Elementary
School. A-43
7.1.3 Results of E-Perm measurements Oakmont Elementary
School during the Winter of 1990-91, in pCi/L. A-44
7.1.4 Results of the CC screening measurements carried out
in Oakinont Elementary School during March 1991, in
pCi/L. A-45
7.1.5 Plan view of the tunnel and arrangement of the HVAC
system at Oakmont Elementary School. A-4 6
7.1.6 Correlation of OA damper indicator and calculated
percent OA using temperatures at Oakmont Elementary
School, Columbus, OH. A-47
7.1.7 Effects of outdoor air in HVAC system on room radon
levels at Oakmont Elementary (before tunnel
sealing). A-48
7.1.8 Effects cf outdoor air in HVAC system on tunnel radon
levels at Oakmont Elementary (before sealing
tunnel). A-49
7.1.9 Effects cf outdoor air in HVAC system on radon levels
at Oakmont Elementary (before tunnel sealing). A-50
7.1.10 Effects of outdoor air in HVAC system on room radon
levels at Oakmont Elementary (after tunnel sealing). A-51
7.1.11 Effects of outdoor air in HVAC system on tunnel radon
levels at Oakmont Elementary (after sealing tunnel) . A-52
8.1.1 Floor plan of Lincoln Elementary School showing
addition dates, room locations, and CC measurement
location. A-53
8.1.2 Winter 1990-91 ATD results and the May 1991 CC
measurements made with UV's on/off at Lincoln
Elementary, in pCi/L, A-54
8.1.3 Comparison of radon levels in Abraham Lincoln
Elementary School (part 1). A-55
8.1.4 Comparison of radon levels in Abraham Lincoln
Elementary School (part 2). A-56
8.1.5 Changes in radon levels with unit ventilator on
compared to levels when off at Lincoln Elementary,
(part 1). A-57
8.1.6 Changes in radon levels with unit ventilator on
compared to levels when off at Lincoln Elementary,
(part 2), A-58
8.1.7 Floor plan of Lincoln Elementary showing locations of
the subslab footings and utility tunnels. A-59
8.1.8 Locations of the subslab communication test points and
the subslab radon levels measured at Lincoln
Elementary, in pCi/L, A-60
8.1.9 Proposed mitigation systems for Lincoln Elementary. A-61
8.1.10 Comparison of HVAC and ASD in Room 1, Lincoln
Elementary. A-62
8.1.11 Comparison of HVAC and ASD in Room 4, Lincoln
Elementary. A-63
ix
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er
12
13
1
2
3
4
5
. 1
.2
.3
. 4
. 5
. 6
. 7
. 8
. 9
. 10
.11
. 12
. 13
Figures (Continued)
Page
Comparison of HVAC and ASD in Room 13, Lincoln
Elementary. A-64
Comparison of HVAC and ASD in Room 16, Lincoln
Elementary. A-65
Plan view of the crawl space and installed ducting
network at Glenview Elementary School, Nashville,
TN. A-66
Typical sub-membrane depressurization system for crawl
spaces. A-6?
Continuous radon levels during the winter follow-up
measurements during various mitigation options at
Glenview Elementary, Nashville, TN. A-68
Summary of the radon levels in Glenview Elementary
classroom and crawlspace during each of the testing
periods, both Spring/Summer and Winter. A-69
Differential pressures and temperatures in both the
classroom and the crawlspace during the testing period
at Glenview Elementary, Nashville, TN. A-70
Partial floor plan showing utility tunnel and room
locations at Lidgerwood Elementary School, Spokane,
WA. A-71
Room over-pressures achieved in Room 139 using the
unit ventilator, Lidgerwood Elementary School, A-72
Room over-pressures achieved in Room 140 using the
unit ventilator, Lidgerwood Elementary School. A-73
Room over-pressures achieved in Room 141 using the
unit ventilator, Lidgerwood Elementary School, A-74
Room over-pressures achieved in Room 142 using the
unit ventilator, Lidgerwood Elementary School. A-75
Location of the suction and test points used during
the subslab communication tests and the radon levels
measured at these points, Lidgerwood Elementary
School, values in pCi/L'. A-76
Results of the subslab communication tests, the values
of SP are the vacuum cleaner suction applied to the
suction point at Lidgerwood Elementary School. A-77
Proposed ASD systems at Lidgerwood Elementary
School. A-7 8
Cross-section view of the suction points proposed for
Lidgerwood Elementary School (the same design should
be used in Rooms 128 and 129). A-79
Summary of the data measured in Room 139 over the
period November 29, 1990 through December 3, 1990. A-8 0
Summary of the data measured in Room 140 over the
period November 29, 1990 through December 3, 1990. A-81
Summary of the data measured in Room 141 over the
period November 29, 1990 through December 3, 1990. A-82
Summary of the temperature data measured in the
classrooms and outside over the period November 29,
1990 through December 3, 1990. A-83
x
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Figures (Continued)
Number Page
10.1.14 Summary of the wind data measured over the period
November 29, 1990 through December 3, 1990. A-84
10.1.15 Summary of the data measured in Room 139 over the
period December 3, 1990 through December 9, 1990. A-85
10.1.16 Summary of the data measured in Room 140 over the
period December 3, 1990 through December 9, 1990. A-86
10.1.17 Summary of the data measured in Room 141 over the
period December 3, 1990 through December 9, 1990. A-87
10.1.18 Summary of the temperature data measured in the
classrooms and outside over the period December 3,
1990 through December 9, 1990. A-88
10.1.19 Summary of the wind data measured over the period
December 3, 1990 through December 9, 1990. A-89
10.1.20 Summary of the data measured in room 139 over the
period December 10, 1990 through December 16, 1990. A-90
10.1.21 Summary of the data measured in Room 140 over the
period December 10, 1990 through December 16, 1990. A-91
10.1.22 Summary of the data measured in Room ,141 over the
period December 10, 1990 through December 16, 1990. A-92
10.1.2 3 Summary of the temperature data measured in the
classrooms and outside over the"period December 10,
1990 through December 16, 1990. A-93
10.1.24 Summary of the wind data measured over the period
December 10, 1990 through December 16, 1990. A-94
10.1.25 Summary of the data measured in Room 139 over the
period December 17, 1990 through December 23, 1990. A-95
10.1.26 Summary of the data measured in Room 140 over the
period December 17, 1990 through December 23, 1990. A-96
10.1.27 Summary of the data measured in Room 141 over the
period December 17, 1990 through December 23, 1990. A-97
10.1.28 Summary of the temperature data measured in the
classrooms over the period December 17, 1990 through
December 23, 1990. A-98
10.1.2 9 Summary of the wind data measured over the period
December 17, 1990 through December 23, 1990. A-99
10.1.30 Summary of the data measured in Room 139 over the
period December 24, 1990 through December 30, 1990. A-100
10.1.31 Summary of the data measured in Room 140 over the
period December 24, 1990 through December 30, 1990. A-101
10.1.32 Summary of the data measured in Room 141 over the
period December 24, 1990 through December 30, 1990. A-102
10.1.33 Summary of the temperature data measured in the.
classrooms and outside over the period December 24,
1990 through December 30, 1990. A-103
XI
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Number
Figures (Continued)
Page
10.1.34 Summary of the wind data measured over the period
December 24, 1990 through December 30, 1990. A-104
10.1.35 Summary of the data measured in Room 139 over the
period December 31, 1990 through January 4, 1991. A-105
10.1.36 Summary of the data measured in Room 140 over the
period December 31, 1990 through January 4, 1991. A-106
10.1.37 Summary of the data measured in Room 141 over the
period December 31, 1990 through January 4, 1991. A-107
10.1.38 Summary of the temperature data measured in the
classrooms and outside over the period December 31,
1990 through January 4, 1991. A-108
10.1.39 Summary of the wind data measured over the period
December 31, 1990 through January 4, 1991. A-109
10.1.40 Correlation of the 8 hour averages of % time UV's on
and % time doors open with radon levels averaged over
same time period. A-110
10.1.41 Correlation of the 24 hour averages of % time UV's on
and I time doors open with radon levels averaged over
same time period. A-lll
xil
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TABLES
Number Page
4.1.1 Radon concentrations measured at Barton Elementary
School, Ft. Collins, CO. B-2
4.1.2 Subslab communication test results at Barton
Elementary School, Ft. Collins, CO. B-3
4.2.1 Radon concentrations measured at Platteville
Elementary School, Platteville, CO. B-4
4.2.2 Pressure field extensions measured during diagnostic
tests at Platteville Elementary School, Platteville,
CO. B-5
6.1.1 Test matrix for Nokomis Elementary, St. Paul, MN, B-6
6.1.2 Actual outdoor air flow ¦CFM) versus damper position
for unit ventilators and AHU unit in Nokomis
Elementary, St. Paul, MN. B-7
7.1.1 Radon concentrations measured at Cakmont Elementary
School. B-8
7.1.2 Fan coil unit flows at Oakmont Elementary, Columbus,
OH. B-9
7.1.3 Data logger parameters measured at Oakmont Elementary
School. B-10
7.1.4 Test matrix for Oakmont Elementary School, Columbus,
OH, (HVAC operated part of the day}, B-ll
7.3.1 PFE measurements in library area at Fifth Avenue
Elementary School. B-12
7.3.2 PFE measurements in multi-purpose room at Fifth Avenue
Elementary School. B-13
8.1.1 Radon screening measurements in the Rapid City Area
School District, Rapid City, SD. B-14
8.1.2 Radon concentrations measured at Abraham Lincoln
Elementary School. B-16
8.1.3 Carbon Dioxide levels measured at Abraham Lincoln
Elementary School. B-17
8.1.4 Test matrix for Lincoln Elementary School, Rapid City,
SD, B-18
9.1.1 Results of blower door measurements at Glenview
Elementary School, Nashville, TN (in the crawlspace
portion of the school). B-19
9.1.2 Summary of parameters measured at the crawlspace part
of Glenview Elementary, Nashville, TN. B-20
10.1.1 UV measurements in Room 139 at Lidgerwood School,
Spokane, WA. B-21
10.1.2 UV measurements in Room 140 at Lidgerwood School,
Spokane, WA. B-22
10.1.3 UV measurements in Room 141 at Lidgerwood School,
Spokane, WA. B-23
10.1.4 UV measurements in Room 142 at Lidgerwood School,
Spokane, WA. B-24
10.1.5 Subslab communication test results at Lidgerwood
Elementary School, Spokane, WA, on August 21, 1990. B-25
xiii
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Table (Continued)
Number Page
10.1.6 Radon levels and percent time classroom doors were
open at Lidgerwood School, averaged over both the
school day (8 hours) and over the 24 hour period. B-26
10.1.7 Weekly average values of percent time classroom doors
open, percent time uv's were on and radon levels at
Lidgerwood School over the testing period. B-27
11.3.1 Collocated duplicate charcoal canister results. B-28
11.4.1 Calibrations of the continuous radon monitors. S-29
xiv
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ACKNOWLEDGEMENTS
The EPA Project Officer, Kelly W. Leo vie of the Air and Energy
Engineering Research Laboratory (AEERL), and the authors, Bobby E. Pyle
and Ashley D. Williamson of Southern Research Institute, would like to
express appreciation to the school personnel who allowed them to use the
buildings to conduct this research. They would also like to thank the
regional, state, and local officials who provided assistance with this
research. Special thanks go to; Tom Borak of Colorado State University;
Eugene Moreau of the Maine Department of Human Services; William Angell
of the University of Minnesota; Kent Van Meter, Ted Sherman, and "Robby"
of the St. Paul Public Schools; David Sands of the Columbus Public
Schools; Don Molstad of the Rapid City Area Schools; and Tom Hatfield
of the Nashville Metropolitan Public Schools. They would also like to
express their appreciation to all of the teachers who sometimes had to
work around the newly installed equipment.
They would also like to thank Felton Perry of Acurex, Ray Coker of
Southern Research Institute, and the following AEERL employees for their
assistance in conducting diagnostic measurements and installing the
datalogging systems: A.B. "Chick" Craig, Timothy M. Dyess, A. Wayne
Fowler, and D. Bruce Harris. Judy S. Ford was the EPA Quality Assurance
Officer for this project.
XV
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METRIC CONVERSION FACTORS
Although it is EPA policy to use metric units in its documents, non-
metric units have been used in this report to be consistent with common
practice in the radon mitigation field. Readers may refer to the
following factors to convert to that system.
Non-Metric
Times
Yields Metric
cubic foot (ft3)
28.3
liters (L)
cubic foot per minute
(cfm)
0.47
liter per second
(L/s)
degrees Fahrenheit
<°F)
5/9 (° F-32)
degrees centigrade
(°C)
foot (ft)
0.30
meter (m)
inch (in.)
2.54
centimeters (cm)
inch of water column
(in.WC)
248
pascals (Pa)
mile per hour (mph)
1.6
kilometers (km)
picocurie per liter
(pCi/L)
37
becquerels per cubic
meter (Bq/m3)
square foot (ft2)
0.093
square meter (m2)
square inch (in.2)
6. 452
square centimeters
(cm2)
xvi
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SECTION 1
INTRODUCTION
The purpose of Environmental Protection Agency's (EPA's) Air and
Energy Engineering Research Laboratory's (AEERL1s5 school radon research
program is to develop and demonstrate low-cost radon mitigation options
for existing and new schools and other large buildings. These mitigation
options must address the unique features of these structures (i.e., large
size, different types of HVAC systems, and varying occupancy patterns).
This report details case studies of the radon mitigation research
conducted by AEERL in 13 school buildings during 1990-92. The first
three sections of this report cover background information and objectives
of this research project, overall conclusions from the research, and the
radon diagnostic and mitigation techniques used in these 13 school
buildings. The next seven sections detail the research conducted in each
of the schools. The sections are organized alphabetically by state
(Colorado, Maine, Minnesota, Ohio, South Dakota, Tennessee, and
Washington). A discussion of the quality control and quality assurance
follows. QA/QC requirements apply to this project. The data are
supported by QA/QC documentation as required by U.S. Environmental
Protection Agency policy. References are listed in the final section.
All of the figures and tables for the report can be found in appendices
A and B, respectively.
1.1 BACKGROUND
Since 1988 AEERL's Radon Mitigation Branch has conducted radon
mitigation research in 50 schools buildings located in 13 states (1).
Initially, AEERL' s radon mitigation research in schools focused on active
soil depressurization (ASD), the most successful radon control technique
in residential houses. To provide an adequate background for the
research efforts covered in this report, it is important to summarize the
major conclusions from earlier research (2);
1) School buildings have a number of physical characteristics that
make their mitigation different, and typically more complex, than
houses,
2) Radon measurements in schools can vary dramatically over time
(seasonally and diurnally), and this variation must be considered
when conducting diagnostics and designing the mitigation system.
3) The following diagnostic procedures are important: review of all
relevant building plans, investigation of the building, analysis of
the HVAC system, and measurement of subslab oressure field extension
(PFE).
4) ASD can be applied successfully in schools .where the slab is
underlain with a clean, coarse layer of aggregate of narrow particle
size range as long as subslab barriers to communication are limited.
5) ASD in schools typically requires greater fan air flow capacity
and suction pipe diameters than ASD in houses.
1
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6) PFE measurements provide essential data on the extent and the
nature of subslab barriers. If all the subslab walls surrounding
the classrooms extend to footings, it is necessary to have one ASD
point for every two rooms and, in many cases, one point for each
room. If the walls between rooms are set on thickened-slab footings
and the aggregate is continuous under the footings, then the subslab
pressure field will extend under the footings.
7) In general, the correlation between classroom radon
concentrations and subslab radon "sniffs" was not particularly good.
8) A majority of AEERL research schools have slab-on-grade
substructures, although some of the schools had portions with
basements and/or crawl space substructures.
9) HVAC systems in the AEERL research schools included unit
ventilators (UVs), fan coil units, radiant heat, ana central air
handling systems. Many of the schools did not have HVAC systems
that were designed to deliver conditioned outdoor air.
10) Many of the slab-on-grade schools run their utility lines in
subslab utility tunnels. Although tunnel depressurization may be a
mitigation option, many of the tunnels contain asbestos.
Because of complicated subslab structures and subslab fill material
that sometimes make ASD systems expensive to install, and because of
indoor air quality concerns (such as carbon dioxide), AEERL has
concentrated part of its recent research efforts in schools on the use
of HVAC systems for radon reduction.
Using the HVAC system to control radon can be beneficial in schools
where ASD is not applicable, and can also be used as a supplemental radon
reduction technique in schools where ASD systems are installed in order
to further reduce radon levels (to reach the long-term national goal of
ambient radon levels established in the 1988 Indoor Radon Abatement Act) .
The HVAC system can also provide improved indoor air quality in addition
to radon reduction through the introduction of additional outdoor air.
Use of the HVAC system as a radon control technique depends on the
specific building, but in general, it may be considered in any school
that has a HVAC system that supplies outdoor air. Specifically, use of
the existing HVAC system to control radon levels is not reasonably
applicable in schools where the existing HVAC system is not designed to
supply conditioned outdoor air (e.g., exhaust-only system, radiant heat,
or fan coil units). Also, restrictions to the use of the existing HVAC
system may apply where the HVAC system does not consistently supply
outdoor air during all seasons, and radon control/indoor air quality
concerns in the school system are overridden by energy cost concerns.
2
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1,2 OBJECTIVES
In 1990 AEERL expanded research of HVAC systems for radon control.
Continuous dataloggers were installed in a number of research schools to
monitor several parameters simultaneously. The primary objective of
these research projects was to better understand the conditions under
which HVAC systems in existing buildings can be used for effective radon
reduction. Criteria used to evaluate the mitigation system effectiveness
included:
- degree of radon reduction,
- long-term reliability as related to mechanical durability and
resistance to intervention,
- installation, maintenance, and operating costs, and
- impact on the indoor air quality in the school.
Since school facility managers may sometimes be faced with a decision
to use either ASD, HVAC control, or a combination of the two techniques
for radon reduction, an additional objective of this research was to
compare the effectiveness of HVAC system control and ASD in the same
1.3 APPROACH
This report details case studies from the research conducted from
1990 through 1992 to address the two objectives discussed above. The
research was conducted in 13 school buildings located throughout the
U.S.: two in Colorado, two in Maine, one in Minnesota, four in Ohio, one
in South Dakota, one in Tennessee, and two in Washington state. The
schools were selected based on a number of parameters including radon
levels, type of HVAC system, building substructure type, and location.
Radon diagnostics were conducted in all 13 schools and mitigation plans
were developed for each.
In addition to providing the details of the diagnostic measurements
and mitigation system performance, this report also presents results from
the first wide scale use of continuous ,dataloggers to study the
interactions of various radon mitigation systems with school operation
and use. Dataloggers were installed in seven of these research schools
to continuously monitor relevant parameters including: .radon
concentration, differential pressure, differential temperature, percent
open of outdoor air damper, operation of exhaust fans, opening and
closing of doors in the building, and carbon dioxide (C02) levels.
AEERL's datalogging systems are described in Section 3 and elsewhere (3).
3
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SECTION 2
CONCLUSIONS AND RECOMMENDATIONS
This report acknowledges the fact that QA/QC requirements apply to
this project. The data described in these conclusions are supported
by QA/QC documentation as required by U.S. Environmental Protection
Agency policy. The following conclusions can be drawn from the radon
mitigation research conducted by AEERL in the 13 school building case
studies discussed in this report;
» If PFE measurements indicate that an ASD system will
be effective, this would be the preferred system for
consistent, trouble-free, and economical radon
control.
• If in addition, improvement in indoor air quality or further
radon reduction is desired, the amount of outdoor air
supplied through the HVAC system should be
increased.Increasing the amount of outdoor air will help to
approach the long-term national goal of ambient radon levels
in buildings established in the 1988 Indoor Radon Abatement
Act,
• Some existing central HVAC systems are not designed
to supply conditioned outdoor air and hence are not
suitable for use as year-round radon mitigation
systems because of energy cost and/or comfort
concerns.
Since it appears that unit ventilators (UVs) reduce
radon levels more by dilution rather than by
preventing radon entry, their successful use as
mitigation systems are probably restricted to
buildings with initial levels in the 4 to 10
picocuries per liter of air (pCi/L) range.
• For school constructed over crawl spaces with
exposed soil, the most successful and mitigation
system is a variation of ASD -- submembrane
depressurizatior. (SMD) — which depressurizes the
area under a plastic membrane covering the soil.
• Where central HVAC or UV systems are used for radon
mitigation, careful attention must be given to the
operation of these units in setback mode at night
and over the weekend. They must be turned on early
enough to lower the radon levels before the building
is occupied. In some of the research schools, HVAC
system start-up at 7 am did not reduce the radon
levels to bslow 4 pCx/L lxmits untxl after 12 noon.
4
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Carbon dioxide levels (an indicator of indoor air
quality) were well above ASHEAE guidelines (4) of
1000 parts per million (ppm) at least part of the
school day in most of the schools where levels were
measured. Typical levels during school occupancy
averaged from 1000 ppm to 1700 ppm. The CO, levels
typically peaked around 10* 00 am and again around
3:00 pm with a decrease during lunch (noon). The
levels were also higher in the winter than other
times of the year* In one ^cxndergarten classroom m
South Dakota the levels over a two-week period
during January 1992 were above 1000 ppm about 7-8 %
of the occupied time and in a classroom of 5th
graders in the same school about 25 % of the time.
5
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SECTION 3
COMMON DIAGNOSTIC MEASUREMENT AND MITIGATION TECHNIQUES
School buildings have a number of physical characteristics that make
them different, and typically more complex, than residential houses.
These characteristics include: building size, substructure, subslab
barriers, HVAC system design and operation, and locations of utility
lines. These physical characteristics can influence radon levels in the
building since they affect radon entry routes, building pressure
differentials, and radon mitigation approach.
The radon'diagnostic procedures used in the schools discussed in this
report include: a review of all radon screening and confirmatory
measurements; a review of all available building plans and specifications
including structural, mechanical, and electrical; a thorough building
investigation to assess potential radon entry routes and to confirm and
to supplement information cited in the building plans; an analysis of the
HVAC system design and operation and its influence on pressure
differentials and radon levels; and measurements of FFE to assess the
potential for an ASD system.
Depending on the specific objectives of each project, varying levels
of diagnostics were performed in the 13 schools discussed in this report.
The discussion below is not intended to be all-inclusive. Other
diagnostic tests that were site specific will be described in the section
in which discusses the school where the measurements were made. The
subsections below provide details on the common radon diagnostic
procedures used for this research. The datalogging system, the
development of the test matrices, and "good" techniques for ASD system
design are also discussed.
•3.1 REVIEW OF RADON SCREENING AND CONFIRMATORY MEASUREMENTS
Initial radon screening, confirmatory measurements, and any
additional measurements followed EPA's interim radon measurement protocol
(5) as closely as possible unless modified to determine the effects of
specific variables. The measurement results were written on a copy of
the school floor plan, along with a description of measurement
conditions. Potentially important measurement conditions include:
operational status of HVAC systemCs>, weather (outdoor temperature,
precipitation, wind, barometric pressure, etc.), and occupied or
unoccupied status of the building during the measurement period.
3.2 REVIEW OF BUILDING PLANS
Building plans and specification documents were obtained for review
when available. Pertinent drawings include architectural, structural,
mechanical, and electrical. The following information relevant to radon
diagnostic and mitigation is typically provided by these plans.
The architectural drawings will give general information on building
design and also provide details on typical wall sections.
6
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The structural drawings will contain information on the foundation,
footing and thickened slab footing locations, and subslab fill. These
will be helpful to assess the potential effectiveness of an ASD system
by indicating the presence, size, and thickness of subslab aggregate and
any barriers to subslab communication such as below-grade walls. The
structural drawings may also provide clues to possible radon entry routes
such as expansion joints and pipe chases.
The mechanical drawings and specifications will provide information
on the HVAC system design (such as duct system design, location, duct run
length, supply/return air flow design capacity, outdoor air intake
locations and flow capacities, and exhaust system locations and flow
capacities). The mechanical specifications should summarize the HVAC
system and identify equipment. For schools with intra-slab radiant heat
systems, the plans are particularly important in locating subslab piping
prior to measuring subslab communication. Where applicable, the
balancing report should also be consulted. Note that 15 cfm of outdoor
air per person is suggested for classrooms in the most recent ASHRAE
indoor air quality standard (4).
The plumbing and electrical drawings should initially be reviewed for
potential radon entry routes. II subslab PFE is to be measured to
determine the potential for an ASD system, these plans must be studied
to determine the locations of subslab utility lines prior to drilling
test holes through the slab. Even if plumbing and/or electrical lines
are run under the slab, review of the plans will usually reveal suitable
locations for test holes. These plans will also indicate potential
trouble spots for the ASD system. These could be subslab vents, water
drains (that go to daylight) or other penetrations that could short-
circuit the pressure field of the ASD system.
3.3 BUILDING INVESTIGATION
A thorough building investigation was conducted to assess potential
radon entry routes and confirm information cited in the building plans
and specifications. Entry routes include floor/wall cracks, unsealed (or
deteriorated) expansion joints, utility penetrations, and open pores of
block walls or unsealed tops of block walls that penetrate the slab.
A chemical smoke stick was used to determine the direction of air
movement through potential entry routes, and a micromanometer was used
to determine the magnitudes of pressure differentials under various HVAC
system operational modes. A continuous radon monitor was used to sample
potential radon entry routes and subslab radon levels. For schools
discussed in this report, a Pylon AB-5 unit with a Lucas cell operated
in a sniffer mode was typically used to assess the relative significance
of suspected radon entry routes and sample subslab radon levels.
Observations made during the building investigation were compared with
the radon measurements and correlations noted.
3.4 HVAC SYSTEM AND PRESSURE DIFFERENTIALS
The HVAC system can have significant influences on pressure
differentials in a school building. Where possible, the school engineer
or other knowledgeable person{s S responsible for operation and
maintenance of the HVAC system were present during the analysis.
7
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The first step was to confirm information found in the mechanical
plans and specifications. Is the HVAC system actually installed and
operated as designed or, for example, have outdoor air intakes been
restricted thus reducing the ventilation capability controlled?
A chemical smoke stick was used to determine whether the building
envelope was pressurized or depressurized relative to the outdoors,
hallway, or subslab, and a micrcmanometer was used to quantify the
pressure differentials. When analyzing the pressure differentials
induced by the HVAC system, measurements were attempted under "typical"
operating conditions. Depending on the type of HVAC system and the
testing constraints of a given school district, these may or may not be
the same conditions under which screening and confirmatory measurements
were made. Attention was also paid to include all exhaust fans that are
not included as part of a central HVAC system.
If the HVAC system was a major contributor to the negative pressures
in the building, it was determined if this was because of the HVAC system
design or because of operation and maintenance practices. If the system
has the design capacity to maintain all building zones under positive
pressure, it may be possible to control radon levels by adjustment of the
HVAC system by a qualified person and if the levels are not too high {<
20 pCi/L). Equipment and/or procedures to identify inadequate HVAC
operation were also important.
If it was suspected that radon was being distributed in the school
by the air-handling system (with a central HVAC system or unit
ventilators), radon "sniffs" in the supply air were compared with radon
levels in the room(s). Elevated levels of indoor radon caused by radon
entry into the return-air system and distribution to classrooms with
recirculated room air can result from, for example: leaky subslab return
air ductwork, unducted return-air plenums in the drop ceiling that are
open to the subslab via open tops of block walls extending through the
slab, and air intakes for unit ventilators that are open to the soil or
-floor-wall joint.
Many schools have not been designed to supply conditioned outdoor air
to occupied spaces and, as a result, do not have the option for HVAC
pressurization with current system design. Typically, with such schools,
the fresh air was intended to be provided through above-grade shell
leakage and openings such as windows. However, many of these schools
have been retrofitted for energy conservation, decreasing the amount of
outdoor air infiltration from above grade. The lack of fresh outdoor air
as a result of these tightening measures can reduce dilution of the
indoor air and increase the driving forces which cause radon entry.
If schools operate an exhaust fan for ventilation purposes or to
remove odors or chemicals and sufficient makeup air is not supplied,
significant negative pressures can result. This will exacerbate radon
entry into the building through below-grade cracks and openings.
In order to quantitate the HVAC system (or systems in the case of UV
systems), several measurements were carried out using a micromanometer
and a flow hood. The total air flow out of the unit and the outdoor air
(OA) supplied into the unit are typically measured at various openings
of the OA damper and at various fan speeds (if applicable). From these
measurements the ventilation rates and the cfm of OA per person can be
8
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calculated. While measuring the flow rates under the various operating
conditions, the pressure differentials between inside and outside are
monitored with a mieromanometer to determine the pressure effects
produced by the HVAC system. These pressurization (or depressurization)
effects become very important if the HVAC system is to be used as part
of the mitigation system.
In addition to measuring air flow rates of the HVAC and UV systems,
4- rv £3 f 1 f\ f"» a t-\ 2 1 i" 1 OC f*ki OVhSlI ct" fane 3 ya fw ni t"0 1 TDT"^ fs l" t- 3 "fr" F*I C C5 i t™ m O C Q
Liic LlUw LGUaL.1 L.J_tro U1 CAiiaUol, i. d 11 o €L -L C liupui IflllL. . U&c U1 LilCoC
fans can increase or in some cases reduce the radon levels (6).
3.5 SUBSLAB PRESSURE FIELD EXTENSION (PFE) MEASUREMENTS
As discussed above, the first step in determining the potential
effectiveness of a school ASD system was analysis of the building plans
to determine the locations and types of subslab walls and footings and
thickened slab footings that may serve as barriers to subslab
communication. The plans typically indicated whether subslab aggregate
was specified. It should be noted, however, that grading of aggregate
is highly variable and the indication of subslab aggregate on the plans
did not necessarily ensure good PFE. If the plans were unavailable, some
of the necessary information was obtained during the building inspection.
One excellent • potential source of information about the subslab
conditions may be the maintenance personnel who may have first hand
information due to repairs or maintenance that required cutting through
the slab. It was also crucial that the locations of all plumbing and
electrical lines were identified from the plans and/or inspection before
drilling into the slab for PFE measurements.
The most important parameter in assessing the applicability of ASD
is subslab communication or PFE, Subslab PFE measurements were made
following AEERL protocols. Clean,, coarse aggregate, approximately 1/2
to 1 in. in diameter (ASTM #5), is preferable for good PFE. PFE was
typically evaluated by using a shop-type vacuum cleaner for suction at
one larger hole (normally located at the potential ASD point) and a
mieromanometer at other smaller holes. The suction hole was at least 1
in. in diameter, and the test holes were approximately 3/8 in. in
diameter and located at various distances and in various directions from
the suction hole, depending on building size and configuration. This
approach helped to indicate the feasibility of developing a pressure
field under various parts of the slab and also helped to identify the
influence of subslab barriers such as thickened slab footings or below
grade foundation walls. It is also helpful in indicating competing
pressures or excessive leakage from subslab ductwork which would inhibit
pressure field development in an ASD system.
Pressures at the primary suction point were typically measured at
suctions of about 8, 6, 4, 2 and 0 in. WC. If communication testing
indicated a pressure of - 0.001 in. WC or lower at a given test hole, it
was likely that an ASD system would be able to depressurize the area.
Final ASD system design depended on the results of the PFE
measurements and on other important factors including building codes
(with regards to penetrating firewalls, etc.), convenience, and
aesthetics.
9
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3.6 MEASUREMENT OF SUBSLAB RADON LEVELS
The radon concentrations under the slab were measured with a Pylon
AB-5 monitor operating in a "sniff" mode. In this mode, subslab gas
samples are extracted through the 3/8 in. diameter test holes drilled in
the slab (these holes were then used in the PFE tests discussed in
Section 3.5).
The Pylon was operated in a continuous mode with the internal pump
pulling approximately 2.5 L/min through a 300 ml scintillator cell. The
counting time for the Pylon was 30 seconds. After obtaining several
background counts, the sampling hose with an in-line membrane (1 pm) or
glass fiber filter was inserted into the subslab hole. The number of
counts obtained in each counting interval was observed and the tube was
removed from the hole after two or three successive counts were obtained
that were within about 10-20 percent of each other. The length of time
that the sampling hose was in the hole was typically around 5 minutes.
The radon concentration was then calculated by subtracting the average
background from the in-hole count, converting the counts to counts per
minute, and then dividing by the cell efficiency (which was usually 1.2
- 1.5 counts/min per pCi/L) . When the background count of the cell
increased to about 200 counts,/min or more, the cell was replaced with a
fresh cell and the "hot" cell was flushed with outdoor air and allowed
to recover before it was used.
3.7 CONTINUOUS MONITORING AND DATALOGGING SYSTEM
A commercial datalogging device (Campbell Scientific, Inc.{CSI} 21X,
Micrologger) was used in all the schools investigated in detail. This
device was equipped with: pressure differential transmitters (Modus
Instruments, Inc.), thermistor temperature sensors ( CSI model 107),
outdoor temperature and relative humidity probe (CSI model 207), wind
direction and speed monitor (CSI model 05103), tipping bucket rain gage
(CSI model TE525), and continuous radon monitors (femto-TECH model
R210F). These sensors were arrayed in a configuration specific for each
of the schools investigated. Data from each of the sensors was sampled
once each 6 seconds (or 15 seconds) and 30-minute averaged results (or
totalized counts for the radon monitors) were stored internally. Once
per day the stored values were downloaded via telephone modem to a
computer located in Birmingham, Alabama. The data were then analyzed
using commercial software (Lotus 1-2-3, Quatro Pro, etc).
3.8 DEVELOPMENT OF TEST MATRICES
For each of the schools researched, a test matrix was developed to
determine the operational parameters of the building and their effects
upon the radon levels in the respective building. In some buildings the
test matrix was fairly simple (i.e., measure radon and pressure
differentials at 0, 50, 100 % OA damper openings) whereas in other
schools the matrix was quite complicated. The degree of complexity of
the matrix depended in some part upon the amount of cooperation obtained
from the school personnel. The individual test matrices are provided in
the respective sections below.
10
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3.9 GOOD TECHNIQUES IN ASD MITIGATION SYSTEMS
In order to address the secondary objective for this research --
comparison of HVAC and ASD systems for radon reduction in schools — ASD
systems were installed in some of the schools. Some general details to
consider when installing the ASD systems included the following (7,8).
• After coring the appropriate size hole through the
slab {i.e., a 7 inch hole for an 6 inch diameter
pipe), suction pits should be excavated under the slab
(with a minimum diameter of 36 inches and a minimum
depth of 12 inches) . The pits will improve the PFE of
the mitigation systems.
• A coupling joint should be used at the floor when .
inserting the vertical suction pipe into the suction
pit. This allows the pipe to rest on the floor and
reduces stress on the sealing caulk, A short piece of
pipe should be glued to the bottom of the coupling to
extend just past the bottom of the slab. This will
ensure that the suction pipe does not fall down into
the pit where it could cut off the suction.
The horizontal overhead pipe runs should be sloped so
that any condensation will drain back into the suction
pit.
The fans should be located outside of the building at
or near roof level. They should be mounted vertically
to prevent moisture collection in the fan housing.
The fan exhaust should be located at least 30 feet
from any air intakes, although, other than the unit
ventilators, none were observed in the vicinity of
these location during the building investigations.
However some heat pumps are mounted on flat roofs.
• Care should be taken to seal all joints in the ASD
piping system. In addition, sealing of the larger and
more accessible cracks between the building interior
and substructure will improve the effectiveness of the
ASD systems.
• A pressure activated alarm system should be installed
in a visible location for each of the ASD systems.
• Penetration of any fire walls should be accomplished
using approved fire stop material.
11
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SECTION 4
COLORADO SCHOOLS
4.1 BARTON ELEMENTARY SCHOOL
Initial radon screening measurements were made in December 1989 and
January 1990. The measurements and other features of the school building
are discussed in detail below (9). Radon diagnostic measurements made
on August 16, 1990 are also discussed.
4.1.1 Building Description
This school building is located in Ft. Collins (Larimer County),
Colorado. The original building was constructed in 1956 and included 7
classrooms and various other support offices and storage rooms with a
total area of approximately 15,750 ft2. The original building included
a boiler room of about 1,300 ft* located in a basement in the southwest
corner. The boiler room contains the HVAC system and the slab is
approximately 11 ft below grade. The remainder of the building is slab-
on-grade construction.
In 1958, an additional six classrooms, a kitchen, and several toilets
and support rooms totaling about 9,500 ft2 were added to the original
building. In 1976, a 2,100 ft2 media center was added to the end of the
northeast wing of the 1958 addition to the building. The last addition
to the building was in 1982 when a 200 f t ^ storage area was added to the
southwest end of the multipurpose (gym) room. The total floor space in
the building is now approximately 29,000 ft2 with a soil footprint of
approximately 27,700 ft2 (this includes portions of the building located
over the boiler room). The floorplan of both the original portion and
the various additions of the building are shown in Figure 4.1.1. The
.layout of the boiler room is shown in Figure 4.1.2.
4.1.2 Pre-mitigation Radon Measurements
Radon screening measurements made from January 15 to 17, 1990 are
tabulated in Table 4.1.1 and shown on the floorplan in Figure 4.1.3. The
average radon level was 6.6 pCi/L with a minimum of 4.8 pCi/L measured
in the kitchen and a maximum of 12.3 pCi/L measured in the main office
of the school.
Most of the rooms were remeasured during follow-up tests carried out
from February 14 to 16, 1990. The results of these tests are shown in
Table 4.1,1 and in Figure 4.1.4. In these later measurements the average
radon level was 7.6 pCi/L with a minimum value of 5.9 pCi/L in the
coach's office and a maximum value of 10.2 pCi/L in the nurse's room.
The January and February results are compared in Figure 4.1.5.
For both the screening and the follow-up tests made during the winter
all rooms were above the 4 pCi/L guideline. An additional test using a
continuous radon monitor was carried out in one room of the school over
the period August 6 to 14, 1990. The levels over this period ranged from
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0.25 pCi/L to 6.5 pCi/L with an average of about 4 pCi/L or less. The
daily diurnal variation in the levels was quite large (in some cases
varying by a factor of 4 to 6 times).
4.1.3 Building Investigation
On August 16, 1990 diagnostic tests were carried out at the school.
The architectural drawings called for 4 in. of crushed stone under the
slabs in most locations. The presence of subslab grade beams was
indicated under all of the classroom walls including the walls separating
the classrooms. These grade beams ranged in depth from 2 ft 8 in. to 3
ft and rested upon deep piers at each of the junctions. The presence of
thickened slabs was also indicated in a few locations. The locations of
the grade beams and thickened slabs are shown in Figure 4.1.6 The
presence of crushed stone under the slab thickening could not be
confirmed. If absent, this may reduce the intra-room subslab
communication. The presence of the grade beams surrounding each of the
classrooms will definitely limit the subslab communication between rooms.
The building plans also indicated that there were utility lines in
the return-air tunnel with multiple penetrations in the walls of the
tunnel. Visual inspection indicated that there were numerous openings
to subslab soil in the return-air tunnel walls. Because of the negative
pressures in the return-air tunnel during HVAC operation, these openings
are likely radon entry routes. The presence of asbestos in the tunnel
was suspected but not confirmed.
4.1.4 HVAC System And Pressure Differentials
The HVAC system for the building includes a central air handler with
a single fan and individual controls in each of the rooms. The HVAC
system operates by time control with the system operating approximately
9 hours during the daytime and off for approximately 15 hours at night.
This schedule is supposedly maintained even during the weekend when the
school is not occupied. The furnace and air handler are located in the
boiler room in the basement at the southwest end of the building. The
boiler room is located about 11 ft below the rooms on the west side of
the Gym as shown in Figures 4.1.1 and 4.1.2.
The HVAC supply ducts are located below the slabs and are composed
of cylindrical cardboard ducts surrounded by poured concrete. In those
areas where these ducts were visible, large gaps were found between the
cardboard tubing and the surrounding concrete. It is highly likely that
in most locations the cardboard tubing has deteriorated to the point that
the supply air is in direct contact with the concrete. Since the ducts
are under positive pressure when the HVAC system is operating, this
probably does not represent a major radon source when the system is on.
The return air from each of the classrooms exits through grill vents
into the hallway, with'the hallway of the building serving as a return
air plenum. From the hallway, the return air is ducted into a central
tunnel that leads back to the air handler in the basement. The air in
the gym is returned through floor grilles in the northeast and northwest
corners of the room directly into the return air tunnel as shown in
Figure 4,1.1. The tunnel runs under the north edge of the gym as shown
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in Figure 4.1.1 and varies in size from about 3 ft by 3 ft up to 4 ft by
4 ft in cross section. The tunnel can be accessed in the boiler room.
The tunnel has numerous penetrations by utility lines that lead to
direct soil contact and probably represent a major radon source. The
fresh-air intake for the HVAC system is located at roof level, and the
air is ducted directly into the HVAC fan chamber through a controlled
louver. Visual observation of the fresh-air intake louver from inside
the fan chamber with the fan operating indicated that the louver did not
open during fan operation. Subsequent investigation by the school
maintenance staff confirmed that the control rod for the fresh-air intake
louver was disconnected. The rod was then reconnected so that the louver
would open properly. It is not clear what control system determines when
and how much the louver opens. During the cold winter days the louver
may be only partially opened. This may be dependent upon the outdoor
temperature.
Investigation of the room pressure differentials (Ap's) was carried
out primarily in the kindergarten room using an electronic
micromanometer. These measurements were made before the fresh-air louver
was repaired. The dp between the kindergarten room and the subslab was
measured to be -0.005 in.W.C. with the HVAC on and the door to the hall
open. When the door was closed the Ap dropped to -0.003 in.W.C. The Ap
between the kindergarten room and the hallway was -0,005 in.W.C with
the HVAC on and the door closed. The pressure of the room relative to
outdoors was -0.005 in.W.C. No Ap measurements were made with the HVAC
system off. However, it appears that the HVAC system is depressurizing
the classroom relative to both the subslab region and outdoors. This
indicates that even in the warm summer months when the HVAC system is
used for ventilation purposes only, it causes room depressurization which
could result in soil gas flow from the subslab into the room. However,
measurements of the radon levels in the building during the period August
6-14, 1990 did not show any elevated levels.
Measurements made with a flow hood from one of the supply vents and
into one of the return vents showed the air flow into the gym is about
235 cfm and about €50 cfm into the return. This unbalanced operation is
a major contributor to room depressurization.
4.1.5 Diagnostic Measurements
Radon concentrations under the slab and at several possible entry
points were measured using a Pylon AB5 in a "sniff" configuration. The
subslab radon levels measured in 0.5 in. diameter holes drilled through
the slab in the Kindergarten room and the office in Room #6 are shown in
Figure 4.1.7. These levels were about 700 pCi/L. Levels of about 300
pCi/L were measured in a crack in the slab adjacent to one of the air
supply registers in the kindergarten room. Sniffing in one of the supply
registers in the gym showed levels of about 15 pCi/L with the air handler
off and about 25 pCi/L with the fan on. Measurements in' the wall cracks
of the air return tunnel showed levels of between 50 and 100 pCi/L with
the fan off. These levels increased to about 350 pCi/L when the fan was
turned on and the tunnel depressurized. This indicates that the
depressurization of the return duct can mine radon from the soil through
the cracks and penetrations in the duct wall.
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Examination of the air handler fan chamber revealed a large crack
(about 0.1 in. wide) in the slab on which the chamber was sitting. The
investigators sealed the crack with duct tape for a length of roughly 4
feet and sealed the hose of the Pylon under the tape. The levels were
measured to be about 700 pCi/L with the fan off and about 800 pCi/L with
the fan on. The AB5 was placed in the fan chamber sniffing the air in
the chamber. The radon levels were about 70 pCi/L with the fan off and
increased to 350 pCi/L to 700 pCi/L with the fan on, indicating that the
slab crack in the fan chamber is a major radon entry route. It was also
observed that the crack was very clean with little or no dust in the
crack. Apparently there is sufficient air flow out of the crack (or
turbulence in the air above) to keep the crack clean. The pressure in
the fan chamber relative to the boiler room was measured to be
approximately -2 in. W.C.
Subslab communication tests were conducted in the kindergarten room
using the suction (Fa) and test holes (Fb, Fc, and Fd) shown in Figure
4.1.7. The results are shown in Table 4.1.2.
The measured Ap's are plotted as a function of the distance from the
suction point in Figure 4.1.8. The values measured at test point Fd may
not have been entirely due to the vacuum cleaner suction. These values
may have been partly (or even entirely) due to wind effects on the
building.
Based upon the limited tests carried out on August 16, 1990 it would
appear that the subslab communications are fair to poor. Consequently,
the pressure field extension that can be expected with an ASD system
would be limited to one or perhaps two classrooms at most.
4.1.6 Mitigation Strategy
Before attempting to install or even design an ASD system for this
school other approaches were attempted.
4.1.6.1 Measure Effects of Outdoor Air (OA) Intake
One obvious approach was to correct the inoperative fresh-air intake
damper. Correction of this problem was necessary for reasons other than
the radon problems. Also, a brief inspection visit to another school --
Moore Elementary School also in Ft. Collins — revealed striking
similarities and contrasts. The two schools have almost identical floor
plans and HVAC systems. However, the radon levels measured in Moore
during January 1990 averaged 0.5 pCi/L with one room measuring 5.6 pCi/L
and the remainder at levels less than 2.1 pCi/L. During the short walk
through examination of Moore it was found that the slab under the air
handler fan was cracked similarly to that in Barton. However the crack
in Moore was not clean and appeared to be filled with cement dust. The
return air tunnel at Moore also had similar penetrations as seen at
Barton. At the time no power was available in the school (the power
boxes were being replaced) so that inspection of the operation of the
fresh air inlet damper was not possible. Later investigations by the
school maintenance personnel found that the damper was indeed opening as
it should. Consequently, the first step in mitigating Barton started
with correcting the fresh air inlet louver.
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4.1.6.2 Determine Optimum HVAC Operation
The effectiveness of the HVAC system with OA dilution was evaluated
tc determine the advantages and disadvantages of this mitigation method.
Even if correcting the OA damper did lower the radon levels to acceptable
limits, it was not known what limits are placed on the damper operation
during temperature extremes and how it would affect energy costs.
A continuous data logger was installed at the school from 1/12/91
until 6/13/91 to monitor building parameters such as: indoor/outdoor
temperatures, indoor/outdoor pressure differences, ambient weather
conditions (wind speed, direction, etc), half-hourly radon levels at key
locations, and the operation of the fresh air supply vent to the heating
system. These measurements were taken with the HVAC system operating in
a variety of configurations. The data were analyzed and a series of
adjustments were made to the HVAC system.
The most effective controlling factor for radon throughout the entire
school was found to be the OA supply. When the OA vents remained closed,
as they were when the original screening test were made, the radon
concentrations remained high. This was because the blower was creating
a large negative pressure along the underground return duct which
extracted radon through cracks from the soil beneath the building. Since
no OA was entering, ventilation was at a minimum and the radon was
recirculated throughout the building. This is illustrated in Figure
4.1.9 where the continuous radon levels for the kindergarten room, room
1, and the levels in the return air tunnel are plotted as functions of
time. Included in this figure are the positions of the OA damper. It
is clear that opening the damper lowers the radon levels, apparently by
dilution of the indoor air in the building.
Studies indicated that radon levels were reduced even' when the OA
supply was only partially opened, but that the concentration increased
rapidly when the supply vents were closed. These results are shown in
Figures 4.1.10 through 4.1.13. It is seen that by opening the OA damper
by about 25-301 reduces the radon levels to approximately 2 pCi/L in the
rooms and in the return air tunnel and to about 25 pCi/L under the slabs.
A test matrix was set up to operate the HVAC system so that the
dampers would remain open about 18% during the night and 100% during the
day. The radon concentration remained below 3 pCi/1 at all times. In
order to minimize radon exposures, without a large energy penalty, the
system was adjusted to remain closed during the night, and then open to
10% at about 4:00 am and 100% from 10:00 am to 4:30 pm.
4.1.7 Results of Initial Mitigation System
Integrated post-mitigation radon levels were measured in December
1991 using E-Perms. The results are shown in Table 4.1.1 in the last
three columns. The school average radon levels was found to be 2.9 pCi/L
with a maximum reading of 3.4 pCi/L in the music room and a minimum of
2.6 pCi/L measured in the principal's office. These values are compared
to the screening and follow-up readings made the previous winter in
Figure 4.1.14.
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4.1.8 Additional Phases of Diagnostics, Mitigation, Future Plans
No additional diagnostics are anticipated other than to have the
custodian regularly monitor the operation of the OA damper openings. A
simple device has been designed and installed to monitor the position of
the OA supply vents. This was installed in the office of the custodian.
This person was instructed to read and record the position of the dampers
each day. If the dampers are not opening, maintenance should be informed
immediately. The entire system should be checked routinely by the
maintenance section at least three times per year.
4.1.9 Estimated Costs
It must be recognized that while using the OA damper to lower the
radon levels is an acceptable solution, no estimate is available
regarding the increased energy consumption. This must be carried out by
the school board personal in order to calculate the annual costs of
increased OA. It would be possible to install an ASD mitigation system
that would reduce radon beneath the slab and foundation and thus
eliminate it before it can enter the school. This would involve an
initial cost in excess of $10,000, although the annual operating cost to
operate the system would be relatively low.
4.1.10 Summary
The research effort at this school building has demonstrated that an
improperly operated central HVAC system was the cause of the radon
problem. This was qualitatively established by comparing the initial
radon screening results and HVAC system operation to the sister building
(Moore) which does not appear to have a radon problem. By using
continuous monitors it was determined that the elevated radon levels were
exacerbated by the inoperative OA damper. Through a series of tests, an
optimum set of operating conditions were developed for the OA damper that
reduced the radon levels to acceptable limits. Another benefit from the
introduction of OA into the school should be an improvement in the health
and well-being of all occupants in the building, although this was not
documented in this study.
4.2 PLATTEVILLE ELEMENTARY SCHOOL
4.2.1 Building Description
This school was originally constructed in 1952 and included
approximately 17,000 ft2 of floor space including 10 classrooms, a gym,
a kitchen, and several offices and storage rooms. In 1983 approximately
20,000 ft2 of additional floor space was added at both the north and south
ends of the original building. Both of the additions are separate from
the original building and connected by outside walkways. The layout of
the original building and the additions are shown in Figure 4.2.1. Thi's
figure also shows the location of the subslab footers that greatly
influenced the degree of subslab communication found during the
diagnostic tests described below. The school as it now exists includes
a total area of 37,762 ft2. The area has 24 classrooms or instructional
support rooms, and several offices and conference rooms.
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4.2.2 Pre-Mitigation Radon Measurements
Radon screening measurements were carried out over the period March
9-11, 1990 using 3 in. diameter charcoal canisters (CCs), During this
measurement period, the HVAC systems were operational with less than 5%
OA. Also during the measurement period the boiler was operated with
outdoor make-up air for combustion (which is the usual operating
procedure). The locations of the CCs are shown in Figure 4.2.2. The
results of the screening test are shown in Table 4.2.1 and in Figure
4.2.3. The school average radon level at this time was 6.3 pCi/L with
a maximum value of 11.1 pCi/L measured in one of the rooms in the
original building and a minimum reading of 0.5 pCi/L measured in the
North addition.
Follow-up measurements were carried out over the period August 8-10,
1990 using charcoal canisters. During this period the HVAC systems were
off and the windows and doors were closed. The results are shown in
Table 4.2.1 and in Figure 4.2.4. The levels measured during these warm
summer days were much less than the March levels. The school average was
only 1.8 pCi/L with a high of 3.8 pCi/L measured in CC 19 located in the
northeast end of the original building, and a low of 0.9 pCi/L measured
in CC 22 located in the North addition. The ambient temperature during
the August tests was estimated to be about 70-80 °F.
The March and August data are shown in Figure 4.2.5 where the
measured values are plotted as functions of the test locations in the
building. It appears then, that the school radon problem can either be
due to the wintertime stack effect, to the depressurization caused by the
HVAC systems, or to a combination of the two. More diagnostic tests
during the colder months were needed to determine the exact cause.
4.2.3 Building Investigation
On August 15, 1990 a team of scientists visited the school. During
the walk-through, the design drawings were obtained. The entire building
is slab-on-grade construction with footers surrounding each longitudinal
group of rooms as shown in Figure 4.2.1. The building plans called for
crushed stone under all slabs. This stone is most likely smooth river
run and was not washed before it was used. Thus the subslab material
likely has a large percentage of silt or fines mixed in so that subslab
communication is likely to be poor. Also, the footers located under the
classroom-to-hallway walls were expected to restrict the communication
across the hallway. The walls of the building (both load bearing and
non-load bearing) are constructed of concrete block. The walls along
either side of the halls extend through the slab to footers in the soil
and may be a significant source of radon entry. However, the walls
between the classrooms do no penetrate the slab and consequently were not
expected to be a major radon contributor.
The utility lines for the buildings are located under the slab and
openings where they emerge from the slab are likely to be good entry
routes for radon into the buildings. One rather large opening in the
slab was found in the gym area underneath the front edge of the stage.
The expansion joint at this location was cracked open with a hole of
about 0.5 to 1.0 in. diameter that appeared to go down to soil level.
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4.2.4 HVAC System And Pressure Differentials
There is no central air handler for the buildings. The heating for
the building is provided by UVs located on the outside wall of each of
the rooms. The UVs are controlled by individual room thermostats. They
have provisions for OA ranging from 51 to over 25%. These OA intakes are
thermostatically controlled. OA is also provided passively for boiler
combustion. Cooling during the summer months is provided by opening the
windows in the various rooms. There are no window mounted air
conditioning units in the buildings.
The original building has fan powered exhausts located in the
kitchen, the cafeteria, and in the restrooms. The 1983 additions also
have fan powered exhausts in the rooms, the corridors and in the
restrooms. .These powered exhausts could also contribute to the elevated
radon levels in the winter by increasing the room depressurizations. No
room depressurization measurements were attempted due both to the
temperature at the time of the diagnostic visits and to time limitations
during the visit.
4.2.5 Diagnostic Measurements
During the August 15th visit to the school, subslab radon levels were
measured at a limited number of locations. The subslab area was accessed
through 0,5 in. diameter holes drilled through the slab. The locations
of the slab penetrations are shown in Figure 4.2.6. . Also shown in this
figure are the approximate subslab radon levels (in pCi/L) measured with
a Pylon AB5 radon detector operating in the sniffer mode. The levels
under the slab of the original building were in the range of 1,500 -
1,600 pCi/L and in the south addition in the range of 1, 800 - 4, 800
pCi/L. These values are also shown in Figure 4.2.6. Sniffer
measurements at other locations such as wall openings and in opening
around the utility penetrations did not indicate any significant radon
levels during the testing period.
Subslab PFE tests were carried out using the slab penetrations shown
in Figure 4.2.6. The suction point, Fa, was located in room 16 (CC #)
and the test hole Fb was located a distance of 12 in. from Fa. The test
hole Fc was located in room 15 and Fd was in room 2. The suction point
Fa in the south addition was located in resource area room 13 (CC #) with
Fb 12 in. away. The test point Fc was in room 12 and Fd in room 10 as
shown in Figure 4.2.6. The results of the subslab communication tests
are summarized in Table 4.2.2 and are shown graphically in Figures 4.2.7
and 4.2.8. In order to plot the pressure differences on a log-scale, the
suction point pressure is assumed to be at a distance of one-half the
diameter of the suction hole (1.5 in. diameter) or 0.06 ft from the
center of the suction point. In both tests no measurable
depressurization could be measured at test points Fd located about 60 ft
from Fa in room 15 and at Fd in the south addition located about 30 ft
from Fa in room 13. The approximate PFEs that could be expected from a
fan are shown in Figure 4.2.9. This maximum extension is about 30 ft in
the original building and about 20 ft in the south addition.
4.2.6 Mitigation Strategy
Based upon the poor PFE and the presence of the subslab footers
indicated by the design drawings, four separate ASD systems were designed
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for this school. These systems are shown in Figure 4,2,10. Specific
design details, should the school system decide to install an ASD system,
are provided in the following section.
4,2.7 Mitigation System Details
System 1 is located along the north-south corridor of the original
building. In this system a 6 in. diameter PVC (SS-40) pipe would run
along the corridor (above the ceiling tiles) and serve as the suction
supply main. From this main pipe 4 in. diameter, schedule 40, PVC drops
would connect to the suction points. The 4 in. suction pipes should
enter the classrooms above the ceiling tiles if possible, and drop down
to the slab penetrations. The suction pits under the slab at each
penetration should be excavated to a minimum size of 36 in. diameter and
12 in. deep.- When the 4 in. suction pipes are installed through the 4.5
in. cored holes in the slab, a coupling joint should be used as shown in
Figure 4.2.11. The fan used should be capable of moving approximately
230 cfm at a static pressure of about 1 in.W.C. and be constructed for
all weather conditions. The fan should be mounted at roof level with the
exhaust directed back over the roof and away from any existing air
intakes. In locating the 6 in. line, care should be exercised to insure
that the water that condenses in the pipe will drain back down to soil
level through the 4 in. suction pipes.
System 2 is located in the south addition of the school. The fan can
be of the same type as in System 1 and could be located in the boiler
room since there is adequate ventilation there, however it would be best
located at roof level. In either location the exhaust should be directed
back over the roof and away from any air intakes. From the fan a 6 in
diameter PVC pipe would extend into the hallway and connect to a 6x4 in.
tee. From the tee sections of 4 in. diameter PVC pipe would run east and
west down the hallway. The individual pipe drops to the suction points
in the various rooms could be constructed using 2 in. diameter PVC piping
since the air flow will be fairly low (based on the communication tests) .
At the slab penetrations, the diameter of the holes need to be at least
4 in. diameter to facilitate excavation of the suction pits. The 2 in.
suction pipes could be connected to the 4 in. slab penetrations using 4x2
in. reducers as illustrated in Figure 4.2.12.
System 3 would be located outside on the north side of the building
adjacent to the main offices as shown in Figure 4.2.10. Two suction
points should be sufficient to cover the rooms in this area. Because of
the anticipated low air flows and the small area of coverage the system
can be constructed of 4 in diameter PVC pipe with drops to the subslab
of the same size. The fan for this system can be smaller that those in
Systems 1 and 2, but should have at least a capacity of 135 cfm at 1
in.W.C. As mentioned in Section 3.9, care should be exercised during
installation to insure that the water that condenses in the lines can
drain back to the soil through the drops.
System 4, as shown in Figure 4.2.10, would be located in the gym.
area. The 4 in. diameter PVC suction pipe could enter the building on
the north side of the gym at a height sufficient to discourage children
from climbing the pipe outside the building. After entering the building
at the rear of the stage the pipe could immediately drop down through the
stage floor and run along under the stage to a point just behind the
storage doors under the stage. Here the 4 in, pipe should turn down and
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go through the slab penetration as shown in Figure 4.2.11. The existing
cracks and openings in the slab should also be sealed with cement and/or
caulking. The fan for this system should be located at roof level with
the exhaust directed back over the roof and well away from any air
i n La ke s .
Care should be exercised in installing the systems to ensure optimum
performance. The suction pits under the slab at each penetration should
be excavated to a minimum size of 36 in. diameter and 12 in. deep if
possible. The fans should be mounted at on near roof level in a vertical
or near vertical orientation {no more than 45° off the vertical). The
fan exhaust should be directed back over the roof and at least 30 to 50
ft away from any roof mounted air intakes.
All local and state building codes should be followed. These may
include: electrical wiring specifications for the fans such as using a
separate circuit breaker and weather proof conduits outside the building,
and the use of fire stop materials around the pipes where they penetrate
the wall between the rooms and the hallway.
4.2.5 Additional Diagnostics and Mitigation
To determine the nature of the radon entry additional CC measurements
were carried out over the period December 24-31, 1990. During this time
two sets of measurements were taken. Over the period December 24-26 the
measurements were made with the UVs on, and over the period December 28-
31 the measurements were made with the UVs turned off. The results are
tabulated in Table 4.2.1 and compared in Figure 4.2.13. The school radon
average with the UVs on was 6.3 pCi/L and with the UVs off was 3.8 pCi/L.
Based upon these results, it would seem that the UVs are depressurizing
the rooms and thus increasing the radon levels. The room-by-room
increase (or decrease) in radon level when the UVs were on as compared
to when they were off is shown in Figure 4.2.14. The school average
increase in radon was 64.3 %. One might conclude that the UVs are the
major source of radon entry into the building. However, as discussed
below, the ambient weather conditions must be considered in the
evaluation.
The outdoor weather conditions were highly variable throughout the
entire sampling periods. Over the first measurement period (12/24-26/90,
UVs on) the average outdoor temperature was about 5°F with a high of 19°F
and a low of -10°F, the wind speed ranged from calm to around 8 mph with
an average speed of 4.6 mph. A low pressure winter storm front pushed
through the area during the period 12/26-27/90. During the second
testing period (12/28-21/90, UVs off) the average outdoor temperature was
approximately 17°F with a high of 40°F and a low of -6CF, the wind speed
ranged from calm to about 10 mph with an average speed of 4.4 mph. Also
during this second period, the winter storm dropped about 11 feet of snow
by 12/31/90. Thus, while it may appear that the UVs were responsible for
the increased radon levels, it may be that the extreme weather conditions
were affecting radon entry more than the UVs themselves.
An additional set of CC measurements was carried out over the period
March 15-18, 1991 before any mitigation was applied to the school.
During this testing period, the average outdoor temperature was 36°F with
a high of 65°F and a low of 16°F. The average wind speed was approximately
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2.5 mph with a high of 10 mph and a low of 0 mph, and the ambient
atmospheric pressure ranged from 625,8 rnmHg to 634,9 miriHg with an average
of 630.8 rnmHg. These data were taken to determine if the mitigation
systems described above were really necessary. The results are shown in
the last 3 columns of Table 4.2.1 and are compared to the March 1990
measurements in Figure 4.2.15, During this test, the school average
radon level was 4.6 pCi/L. The highest reading was 7.5 pCi/L measured
in one of the offices and the lowest reading of 1.4 pCi/L was measured
in 4 office spaces. The school also conducted a set of long-term (9
month) alpha track detector (ATD) measurements from 9/12/90 through
12/13/90. These long-term tests showed an average radon level of 3,7
pCi/L and, as a result, an ASD system has not been installed in the
building,
4.2.9 Estimated Costs
It is difficult to estimate the cost of the mitigation systems
described above. However, the installed systems will probably cost more
than §15,000.
4.2.10 Summary
This school demonstrates that radon levels can vary quite a lot
during different measurement periods. Because of the seasonal
differences, the first two sets of radon measurements (March 90 and
August 90) gave widely different results. The 9 month ATD results taken
over the period 9/12/90 through 12/13/90 fell somewhere between the first
two test results. The CC measurements carried out to determine the
effects of the HVAC units upon the radon levels (12/24-31/91) were done
during a period of extremely unstable weather conditions and the results
are suspect. And finally, followup CC measurements carried out in March
1991 indicate that the school average radon level (4.6 pCi/L) is border
line.
Under the assumption that the school does have a radon problem severe
enough to warrant mitigation of the entire building, the construction
details of the building provide many obstacles that will have to be
overcome in installing an effective mitigation system(s) . The mitigation
system needed to control a radon problem in these cases with poor subslab
communication is quite complex as illustrated in Figure 4.2.10 above.
It also demonstrates that there is no substitute for good diagnostic
measurements before designing a mitigation system. Also, the variability
of the CC and ATD results along with the low school average radon level
obtained frout all the tests (6.3, 1.8, 3.7, 6.3, 3.8, anc 4.6 pCi/L in
Table 4.2.1) would seem to indicate that mitigation need be applied only
to those rooms that consistently measured above 4 pCi/L unless the intent
is to bring all the indoor radon levels down to ambient levels.
22
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SECTION 5
MAINE SCHOOLS
Two schools in Maine were investigated in September 1990. One of
these schools was located in the town of Sanford about 50 miles southeast
of Portland, Maine (10) and the other was located in the town of Gray
about 20 miles north of Portland. The diagnostic measurements made and
the mitigation systems installed in each school are discussed separately
for each school.
5.1 SANFORD MIDDLE SCHOOL
5.1.1 Building Description
This school is located about 30 miles south of Portland in the
southern tip of Maine. The original building was constructed prior to
1940. In 1940, the building was partially destroyed by fire. The
existing building was constructed over the remains of the original
building in about 1940-41. In some locations there exists portions of
the old building slab under the slab of the new building. The portion
of the school discussed in this report is a three-storied wing on the
northwest end of the main school building. This wing has three floors
each about 3,000 ft2 in area. The lower floor or basement is
approximately 4 ft below grade on all sides. The basement is shown in
Figure 5.1.1 and has a concrete slab floor with footers located between
rooms A13/A14 and room A15. The two floors above the basement are of
wood construction. The roof of the building is flat and constructed of
wooden joists and covered with 2 in. planking and a rubber membrane. The
walls of the structure are brick.
5.1.2 Pre-Mitigation Radon Measurements
Screening measurements of the radon levels in the school were made
by EPA's Office of Radiation Programs (ORP) as part of their School
Evaluation Program (SEP). These measurements indicated that the lower
levels of the school had radon levels consistently above 4 pCi/L with the
highest levels in rooms A12, A.13/14, and A15.
5.1.3 Building Investigation
September 11-14, 1990 diagnostic tests were carried out in the
basement rooms shown in Figure 5.1.1. No design drawings for the
building were available so the locations of subsxab footers were
estimated based upon previous PFE tests. It was concluded that there was
some type of subslab barrier between rooms A13/14 and A15, consequently
communication under the slab would be limited based upon the location or
locations of possible suction points.
5.1.4 HVAC System and Pressure Differentials
The basement rooms shown in Figure 5.1.1 are not served by any
central HVAC system. There is a ceiling mounted UV located in the A13/14
area, and there is a ventilation shaft that runs from the basement to the
roof of the building. It was thought that this ventilation shaft could
produce depressurization in the basement during winter conditions.
Inspection of the vent hood on the roof revealed a damper, however the
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operation had been defeated so that the damper was always in the fully
open condition. The UV in the basement did not appear to supply OA.
5.1.5 Diagnostic Measurements
Continuous radon monitors (Honeywell Model A9000A) have been located
in the basement rooms over various time periods. During the time of the
diagnostic visit, outdoor temperatures were in the range of 60° to 70° F,
and the windows of the rooms were open. Consequently, no detailed
measurement of radon levels or entry routes was carried out.
5.1.6 Mitigation Strategy
Due to the lack of other options, it was concluded that an ASD system
was the logical choice. Because of the possibility of subslab flow
obstruction caused by the footer between rooms A13/14 and A15, a suction
point was installed in each room. The suction points were connected to
a common suction pipe that ran up through the two floors above and out
the roof of the building. On the roof, a single fan was used to provide
suction to both points in the basement. The ASD system was constructed
using schedule 40 PVC pipe as shown in Figure 5.1.2.' The suction pits
under the slab were excavated to a depth of about 12 in. and a diameter
of about 36 in. The fan installed on the roof of the building had a flow
capacity of-230 cfm at a static pressure of 1 in.W.C. The location of
the fan on the roof of the building is shown in Figure 5.1.3.
5.1.7 Results of Initial Mitigation System
After the ASD system was installed, subslab PFE was measured using
the fan and two suction points of the ASD system as the suction source.
The results are shown in Figure 5.1.2, where the values on the left of
the "/" were measured with the ASD system installed but with the fan
turned off and the values to the right were made with the ASD fan
running. From the values measured-at the two suction points, it appears
that a significant stack depressurization effect was produced by the PVC
piping. This passive soil depressurization (PSD) may lower the subslab
radon levels in the immediate vicinity of the suction points but as the
data show, no depressurization could be measured at any of the other,
more distant, test points drilled through the slab. In fact, the static
pressures under the slab at most of the test points were positive as
shown in Figure 5.1.2. This may have resulted from depressurization of
the basement rooms by the open vent stack running from the basement to
the roof.
When the fan was turned on the pressures measured at all of the test
points were negative, indicating excellent subslab PFE. Negative
pressure was also measured in room A12. This was somewhat surprising
since this room is located in the original building rather than in the
addition where the ASD system was installed. It would appear that the
subslab regions can communicate most likely through the connecting
hallway since the wall of room A12 appears to have been an exterior wall
at one time. The flow out of each of the suction points was measured
using a hot film anemometer. The flow from suction point #1 located in
A15 was estimated to be 6 cfm and from suction point #2 in A13/14 was 15
cfm. These values are consistent with the operation curves for the fan
used.
24
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Post-mitigation radon measurements were taken using Honeywell
continuous radon monitors. The results are shown in Figure 5.1.4. For
these data, the monitors were started at 1015 hours on September 10, 1990
and recorded the radon level at 4 hour intervals through 1000 hrs on
September 14, 1990. The monitors were located in rooms A14 and A15.
Installation of the ASD systems began on Monday 10 September at around
1200 hrs and continued through 2000 hrs on the same day. Installation
continued on Tuesday morning 11 September and the ASD fan was turned on
at approximately 1300 hrs. The communication measurements were made at
approximately 1600 hrs on Tuesday 11 September 1990. From the radon
levels shown in Figure 5.1.4 it would appear that the ASD mitigation
system will keep the levels in the basement below 2 pCi/L.
5.1.8 Summary
Although the initial subslab communications test results did not
appear very promising at this school, the communication using two suction
points with pits under the slab did provide excellent PFE. One other
interesting observation was the existence of -0.01 in.W.C, pressure at
the suction points produced by the stack effect. This is a fairly large
depressurization in view of the time of the year (September 11, 1990) and
minimal indoor/outdoor temperature differential. (The outdoor
temperature was in the 65-75°F range.)
5.2 RUSSELL ELEMENTARY SCHOOL
5.2.1 Building Description
This school is located about 20 miles north of Portland in the small
town of Gray. The building is "T" shaped with three wings connected to
a central area as shown in Figure 5.2.1.
5.2.2 Pre-Mitigation Radon Measurements
Screening measurement indicated radon concentrations greater than 20
pCi/L in several schools in Gray. It was decided to include one of these
schools in the research program an to assist in radon diagnostic testing
and mitigation planning.
5.2.3 Building Investigation
During the summer of 1990, a diagnostic investigation of these
schools was carried out. This investigation focused on the ventilation
system configuration and operating condition and on the subslab and the
radon source strengths and PFE. Russell Elementary presented a promising
research opportunity as each of its three wings used different
ventilation systems with the hot water heating offering an excellent
setting to compare different mitigation approaches.
5.2.4 HVAC System
The West wing is the oldest wing and has no ventilation. This wing
in the past has relied upon window and door leaks for ventilation but
these sources have since been sealed for energy reasons. The North wing
has powered exhaust systems to remove air from the rooms. UVs with OA
vents provided the East wing ventilation. Thus, radon mitigation systems
25
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and indoor ventilation effectiveness could be investigated under three
different conditions within one structure with a relatively consistent
radon source strength.
5.2.5 Diagnostic Measurements
PFE tests were conducted in the North wing with the powered exhaust
system to determine the subslab flow conditions. limited P FE W3 s
measured, but at least one room could probably be mitigated with each
suction point.
5.2.6 Initial Mitigation Systems
The West wing was an obvious choice to test the effectiveness of
increased ventilation on total indoor air quality through the use of a
heat recovery ventilator (HRV) , A local ventilation contractor was hired
by the SEP group (6) to install an HRV in one (room 1 of Figure 5.2.1)
of five rooms in that wing. The unit was installed near the middle of the
outside wall of that room. No electric reheat was included to limit
energy usage. The discharge was ducted to four 8 in. circle diffusers in
the ceiling. Return air was taken in at the bottom of the unit. Total
design air delivery was 450 cfm on low speed and close to 600 cfm on high
speed.
The ground surface outside the North wing was paved for playground
activities and, thus, a unique situation presented itself to try to
control the subslab radon levels by applying a suction beneath this
outside area near the building. A two point system was installed on one
side of this wing to test this concept.
The East wing was used to test the effectiveness of UVs as indoor air
mitigation systems. These old systems were brought back to design
condition by the controls manufacturer. The UV systems were repaired and
adjusted and all filters were replaced at the same time.
5.2.7 Results of Initial Mitigation
Testing of these systems was performed during September, 1991 with
CCs and At-Ease continuous radon monitors. The HRV in the West wing and
UVs in the East wing showed pronounced control of the radon while the
"playground ASD" did not solve the problem in the North wing
The lack of control in the North wing was traced to incomplete PFE
across the rooms. Some pressure field was detectable along one interior
wall, but none along the opposite wall. Further investigation revealed
a break in the outside wall near one of the suction points. This break
was for the sanitary drain line and was allowing the pressure field to
develop across the wall, but the tight soil was not allowing it to extend
across the room.
Monitoring of the other sections of the building showed the HRV was
maintaining fairly good control of the radon while the UVs were
ineffective when the cold outdoor temperatures caused the outdoor air
vents for the UVs to close. The lack of reheat and high delivery meant
the winter air supplied by the HRV was perceptibly colder. Dry bulb
temperatures were equal to the rest of the building, but walking into the
room was cooler to the skin. Measurements of the air flow in November
26
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1991 showed 285 cfm on low arid 328 cfm on high speed, about half the
design values,
A noticeable increase of radon levels for a period of approximately
12 hours was noted in a number of instances. These periods correlated
with the start of a significant drop in the barometric pressure as shown
in Figure 5.2.2. It has been hypothesized that a "barometric pump" is
created when the atmospheric pressure is lowered by a frontal passage,
but the soil is sufficiently tight to prevent quick propagation through
the soil under the building. The delay means the pressure under the slab
remains at the higher pressure and the soil gas is pumped into the
reduced pressure in the building.
5.2.8 Additional Diagnostics and Mitigation
Additional testing with continuous radon monitors confirmed the
failure to control the radon with the external ASD. It was decided to
use the school for research for applying ASD systems to tight soils.
Extensive PFE testing was conducted in the North wing in November, 1991.
Low flows were found from the test suction points (8 cfm) with vacuums
in excess of 1.5 in. W.C. providing PFE across one room. The building
plans indicated the rooms on each side of the hall were built on a common
foundation box so pressure fields could be developed under the dividing
walls. A multi-point suction system was designed to put a suction point
in every other room. The low flows from each suction point meant that 2
in. diameter PVC pipe could be used for the drops from the 4 in. overhead
pipe. A dual fan systems was built into the exhaust to allow comparison
of standard mitigation fans and the newer high vacuum units. A valving
and power switching system was installed so only one fan would operate
at a time. The low-pressure, high-flowrate fan operated at 2.5 in. W.C.
for the six suction points, but could not maintain all of the rooms below
4 pCi/L as shown in Figure 5.2.3. When the high vacuum fan was operated,
better PFE and radon reduction was obtained from the 5.5 in. W.C.
suction. Long term monitoring of the system was provided by an industrial
("¦Ant1 va! V*>^ccsH 1 nnr'i \ ranr! a "? rtVi +" "i n n ah c ri wati i f Ar c
L-OI1 Li_vJ-l. UabCU Ufl LcIIUUm J. 11U DyoLClil \ / a i i Li c -L U J i L L,wlLL_LiiLlULl»3 L. a vi\J 11 Lllv/11 i LUI g .
The failure of the UV systems to control the radon levels in the East
wing in the winter and the success achieved with the North wing led to
diagnostic and design work in the East wing to install a high vacuum ASD
system. The flows out of the test holes were slightly higher than the
North wing resulting in a higher total air flow which reduced the suction
available from the fan as indicated by the fan curve. The performance of
the system could be improved by splitting the installed system which cut
the air being moved by the fan in half. The reduced flow would move the
operating point of the fan up the curve and result in a higher suction
increasing PFE. At this time, a single fan was installed to establish the
ability to duplicate the performance obtained on the North wing.
The HRV was modified by replacing the small circular diffusers with
2 ft by 2 ft diffusers with four directionally adjustable grills. It was
hoped that the reduction in delivery velocity by a factor of 4 would
provide less of a wind chill effect. Also, it was suspected that the
original small diffusers were responsible for the actual air flows being
lower than the design values. After replacing the diffusers the flows
in the HRV were remeasured. The low flow rate was 450 cfm, and the high
rate was 600 cfm. These values represent the design values and should
27
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improve the efficiency of the unit. A design for a hot water reheat coil
was also provided to the school.
The high vacuum fans for the ASD system were initially installed
outside to prevent any radon leaks within the building. This was not
recommended by the manufacturer and the researchers soon found out why.
A power outage during an extended cold period stopped the fans for a
significant length of time. The fan on the East wing failed to start when
the power came back on. Examination of the fan by the manufacturer showed
condensation had shorted the unprotected electric circuits in the box
which are normally protected by the warm ambient temperatures when
mounted inside the building. The fan was replaced and the radon levels
were lowered almost as well as in the North wing.
The new diffusers greatly improved the perceived comfort in the HRV
room well into the fall. The arrival of cold winter temperatures brought
the return of the discomfort experienced the previous winter prior to the
installation of the reheat coil. The radon levels were still under
control except for some periods when the "barometric pump" was operating.
The data stations were modified for the second year by adding a
commercial data logger which included a modem for direct data transfer
to remote computers. In conjunction with the indoor air studies conducted
at the school, continuous C02 monitors were added in a few rooms. The HRV
data shown in Figure 5.2.4 shows levels less than 1000 ppm except
Wednesdays when the readings doubled. This is probably due to increased
activities of the children which increased their respiration rate.
5.2.9 Summary
The research conducted at Russell has shown that schools with tight
soils can be mitigated using ASD systems if sufficient suction is
applied. Occasional radon peaks have been noticed when low pressure
fronts move through the area. The system recovers to levels near or below
'2 pCi/L after about 12 hours.
The HRV does provide radon and CO- control, but at an unacceptable
comfort penalty. Reheat is needed in the cold climates for the unit to
be acceptable by the occupants.
Cold climates similarly limit the successful application of UVs for
indoor air control. The freeze protection circuits of some state mandated
energy requirements shuts off the outdoor air supply whenever
temperatures fall below freezing. When the outdoor air is closed, radon
control is limited.
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SECTION 6
MINNESOTA SCHOOL
6.1 NOKOMIS ELEMENTARY SCHOOL
This school (11) is .a single story concrete masonry building with a
brick veneer and slab on grade foundation located in eastern St.Paul.
6.1.1 Building Description
The floor plan of Nokomis is shown in Figure 6.1.1. The total floor
area is around 15,000 ft2. The nature of the subslab footings is not
available at the time of this report. The subslab material is packed
sand.
6.1.2 Pre-Mitigation Radon Measurements
The average radon level in the school was 4.2 pCi/L as measured by
CCs in October, 1990. The highest and lowest concentrations were 6.4
pCi/L and 2.8 pCi/L, respectively.
6.1.3 Building Investigation/'HVAC System
The HVAC systems in the school are a combination of systems. Hot
water for these systems is provided by a gas/oil fired boiler located in
the northwest corner of the building. Each of the nine classrooms (rooms
101, 102, 103, 104, 105, 106, 107, 108, and 109) are heated with finned-
tubes along the outside walls. In addition, the two classrooms on the
south end of the building (rooms 107 and 108) have hydronic slab heating
(these classrooms are used as kindergarten rooms). Heating and cooling
in all of the classrooms is provided by UVs located along the exterior
walls with outside air capability. The gym/lunchroom, kitchen, and the
office complex are serviced by a central air handling unit (AHU) with
ducted returns. The unit has provisions for OA intake at roof level.
There are fan powered exhaust fans in the restrooms and in the kitchen.
Previous investigations of the building indicated that the OA intake
capabilities of the UVs and AHU unit exceed the exhaust fan capacities
so that building pressurization appeared to be a viable option for radon
control. A fan door test conducted on the building revealed an effective
leakage area of around 500 in.2 This indicates that about 3000 cfm of
outdoor air is needed to pressurize the building adequately to prevent
radon entry when the exhaust fans are on. PFE measurements indicated
that a pressure field could be extended about 15 ft from the suction
point.
6.1.4 Mitigation Strategy
In May 1991 a private contractor mitigated the school using three
mitigation systems. One system used the UVs in rooms 101 to 106 to bring
in the minimum amount of OA necessary to pressurize the rooms to reduce
the radon entry. During normal operation the OA dampers modulate above
this minimum setting as determined by indoor and outdoor temperatures.
This was also attempted in rooms 107 and 108; however, the radon levels
were not reduced below 4 pCi/L during the initial evaluation. An ASD
system was then installed in these two rooms with a single suction pit
29
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installed in each of the two closets. The pipes from each point were
connected and run to a single, roof-mounted, exhaust fan capable of
moving 420 cfm at 0 in. W.C. and about 180 cfm at 1.6 in. W.C. The
locations of the ASD points are shown in Figure 6.1.1.
The Gym/Office area in the north end of the building was mitigated
using a combination of HVAC control and another single-point ASD system.
The suction point was located in the boiler room very close to the
utility tunnel. This location resulted in bypassing the subslab area by
pulling air through the tunnel block walls instead of from the subslab.
Post-mitigation radon levels with all systems operating averaged below
0.5 pCi/L.
6.1.5 Diagnostic Measurements
In January 1992 a datalogger was installed in the school in order to
determine how the various mitigation systems performed relative to each
other ana the interactions between each pair of systems. Parameters
monitored were: radon levels in rooms 106, 107, 108, and the principal's
office; subslab differential pressure measurements in rooms 106, 107,.
and the principal's office; OA damper positions on the UVs in rooms 106
and 107 and on the office AHU; temperatures in rooms 106, 107, the
principal's office, and outdoors; and wind speed and direction.
The test matrix shown in Table 6.1.1 was developed to evaluate each
of the mitigation systems. School Officials were unwilling to turn the
ASD systems off while the building was occupied (to test the HVAC systems
alone) . As a result, testing with the ASD systems off was done over the
spring break, April 10 to 20, 1992. These tests should be representative
of winter conditions as the outdoor temperatures during this testing
period ranged from 18 to 43°F, with an average of 30°F. The testing
schedule for this school was as follows:
Test 1, UVs and AHU at normal damper operation; ASD on: This test
was used to measure the radon levels in the post-mitigation configuration
with the ASD and HVAC systems all operating. Under normal conditions the
OA damper modulated based on OA temperature. This is typically 20 to 25%
damper opening.
Test 2, UVs, AHU, ASD off: To collect baseline (no mitigation) radon
data, all UVs and the AHU were turned off. The ASD fan was turned off,
and outlets on the roof were covered with plastic and sealed with duct
tape on Friday afternoon, April 10, 1992. The ASD systems remained off
through Test 6.
Test 3, UV's and AHU on, damper closed: On Monday morning, April 13,
1992, the UVs in rooms 101 to 108 and the AHU were turned on but the OA
dampers were kept closed (UVs and AHU running 24 hours). The school was
operated in this configuration until Wednesday morning, April 15, 1992.
Test 3A, UVs and AHU on, dampers closed, filters out: On Tuesday
afternoon, April 14, 1992, it was found that the return air filters in
the UVs and the AHU were extremely dirty. The filters were pulled out
of the units and the systems continued to operate as described in Test
3, above.
30
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Test 4, UVs and ABU at 10% damper open: On Wednesday morning, April
15, 1992, the OA vents were opened to 101 OA on both the UVs and the AHU
(running 24 hours), The ASD systems remained off. The school was
operated in this configuration until Friday morning, April 17, 1992.
Test 5, UVs and AHU at 50% damper open: On Friday morning, April 17,
1992, the OA vents were opened to approximately 501 OA on both the UVs
and the office HVAC system (UVs and HVAC running 24 hrs) . The school was
operated in this configuration until Saturday afternoon, April 18, 1992.
Test 6, UVs and AHU at normal danqser open: On Saturday afternoon,
April 18, 1992, the UVs the office HVAC system were changed to normal
day/night operation (night setback at 68°F) . The ASD systems remained off
with exhaust pipes covered.
Test 7, UVs and AHU at normal damper operation; ASD on: On Monday
afternoon, April 20, 1992, the ASD system pipes were uncovered and fans
turned on. The UVs and AHUs returned to the post-mitigation
configuration.
Test 8, same as Test 7 (2 weeks later).
Test 9, UVs, AHU, ASD off: These additional tests were carried out
in July 1992 to test the ASD systems. In this test all systems were shut
down at 8:00 am on Friday, July 10, 1S92 to let radon levels go to
background (pre-mitigation) levels.
Test 10, UVs, AHU Off, ASD on: At noon on Wednesday, July 17, 1992
the ASD systems were turned on while the UVs and AHU remained off.
Test 11, UVs and AHU at normal damper operation; ASD on: At 1:00 pm
on Wednesday, July 22, 1992 the UVs and AHU were turned on and operated
as in the post-mitigation mode.
The amount of OA introduced into each of the UVs and the AHU as a
function of damper position is shown in Table 6.1.2. Note that in this
Table, the percent damper opening corresponds to different percentages
of OA for each of the four locations monitored. For example, a 10%
damper opening corresponds to 27, 38, 34, and 19% OA for rooms 106, 107,
108, and the office, respectively. For simplicity, the remainder of this
discussion will refer to the percent damper opening rather than the
percent OA. Refer to Table 6.1.2 for the specific quantity of OA for a
given location and damper position.
6.1.6 Results of Diagnostic Measurements
The results of the nine initial tests are shown in Figure 6.1.2 and
the three additional tests in Figure 6.1.3, The average radon levels for
the principal's office, room 106, and room 107 are plotted for each of
the test conditions (except for the three additional tests shown in
Figure 6.1.3 where the radon monitor in room 106 lost power). Radon
levels increase from Test 1 to 2 because of stack effect induced radon
entry. With the ASD systems operating (Test 1), the stack effect is
reversed. The operation of the UVs with OA also helps to reduce the stack
effect.
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The results shown under Test 3 and 3A are conditions in which the UVs
and AHU are depressurizing the building because the OA dampers are
completely closed. In addition to building depressurization, it is also
possible that the radon levels increased from Test 2 to Tests 3 and 3A
because background radon levels continued to build up in the building
after turning off the ASD systems (Test 2).
With minimum OA (approximately 10%, damper opening in Table 6.1.2)
the radon levels were reduced below 4 pCi/L during Test 4. With about
50% damper opening (Test 5), the radon levels are reduced to background
levels. In fact, the levels during Test 5 were lower than normal UV and
AHU operation together with the ASD system operation. In Test 6 the UVs
and the AHU OA dampers were returned to the post-mitigation setting of
approximately 20 to 251 OA. Turning on the ASD systems in Test 7 reduced
the levels in the Office and in Room 107 but had little effect in Room
106 since there is no ASD system in Room 106.
Test 8 presents continuous data collected about 14 days after Test
7. Radon levels in the two areas with ASD systems are relatively
consistent with those observed during Tests 1 and 7. The radon levels
in room 106 (without the ASD system) are slightly lower than in Tests 1
and 7.
Test 9 results were obtained by turning off the UVs and AHU and
turning off the ASD fans and covering the exhausts with plastic. These
values represent the un-mitigated levels and are somewhat higher than
those obtained in Test 2 above. This may be due to the fact that prior
to construction of an addition to the building, a 4 ft square hole was
cut through the slab in room 107 with the soil exposed to the room.
The results of Test 10 illustrate, at least in the office and in room
107 that the ASD systems operating alone are capable of effectively
lowering the radon levels. The levels are further reduced when the UVs
and the AHU are turned on in Test 11.
The lowest radon levels in these three rooms were observed during
Test 5 when the UVs and AHU were operated at 501 damper position (refer
to Table 6.1.2 for actual percent OA) and the ASD systems were off.
However, it is often difficult to consistently depend on 50% damper
position when outdoor temperatures drop below freezing. In this series
of tests, the UVs do maintain radon levels below 4 pCi/L in all three
rooms as long as the damper position is set to 10% OA (Test 4).
Results show that radon levels are consistently reduced below 1 pCi/L
in rooms 107 and the office when the ASD systems for these areas are
operating. During these tests, the radon levels in the rooms with the
ASD systems were always lower than in the room with only the UV control
(Room 106) .
6.1.7 Summary
The UVs were effective in reducing the radon levels to below 4 pCi/L
in Nokomis if a minimum amount of OA was supplied. If the damper
32
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position was set at 50%, then average radon levels were reduced below 1
pCi/L. Radon levels were consistently reduced below 1 pCi/L in rooms 107
and the office with the ASD systems operating and the HVAC system set to
normal OA. During these tests, the radon levels in the rooms with the
ASD systems were always lower than in the room with only the UV control.
The effectiveness of the ASD system alone was evaluated in Test 10. From
the results of this test it would appear that the ASD is quite successful
in consistently lowering the radon levels to acceptable levels in room
107 and the office without the UV and AHU systems.
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SECTION 7
OHIO SCHOOLS
Initial radon measurements (12) in the Columbus Public Schools (CPS)
system were made during December 1990. These tests were carried out on
approximately 152 of the 168 buildings in the school system. Of those
tested, 80% were found to have at least one room above 4 pCi/L. A
priority list was developed based upon these measurements to identify the
buildings with the highest radon threat. The buildings that were located
highest on the list were Fifth Avenue Alternative School, Oakmont
Elementary School, Hubbard Elementary School, Clarfield Elementary
School, Southwood Elementary School, and Sullivant Elementary School.
These schools were visited on December 18, 1990. During this initial
visit the architectural plans were examined and a brief walk-through was
conducted at each school. Following this initial contact with the CPS,
five buildings were identified for possible inclusion in EPA's school
mitigation program: Oakmont Elementary, Fifth Avenue Elementary, Hubbard
Elementary, Clarfield Elementary, and Southwood Elementary.
A second visit to the CPS was carried out March 4-8, 1991. During
this diagnostic visit it was discovered that Fifth Avenue was not an
appropriate choice for intensive evaluation and was replaced with
Sullivant Elementary. Also, it was concluded that Hubbard Elementary
might be susceptible to mitigation through changes in the building shell.
Consequently, only two building were selected for long-term diagnostics
and evaluation, these were Oakmont Elementary and Sullivant Elementary.
Diagnostics were carried out on other schools but the body of this report
will concentrate on these two schools.
7.1 OAKMONT ELEMENTARY SCHOOL
This building is located at the eastern edge of the CPS district near
the community of Reynoldsburg. The original school building was
constructed in 1966 and includes 13 classrooms, offices, and a
multipurpose room. The area of this slab-on-grade building is 24, 000 ft2.
A slab-on-grade addition was constructed in 1973, bringing the total area
to 31,000 ft2. The floor plan of the school is shown in Figure 7.1.1.
The 1973 addition has a central HVAC system for heating and cooling. All
of the ducting for this system is located overhead. Since pre-mitigation
radon measurements indicated that the radon problem was more urgent in
the original building than in the addition, the addition was not part of
this research project.
7.1.1 Building Description
A subslab utility tunnel runs under the three corridors in the
school. The tunnel walls are constructed of unpainted concrete blocks
(both sides of the blocks were untreated), facilitating airflow from the
soil to the tunnel. These utility tunnels run the length of the building
both east and west and southward (as seen in Figure 7.1.1). Examination
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of the design drawings revealed subslab footings in addition to the
tunnels. These footing locations are shown in Figure 7.1.2. The hall
walls are continuations of the tunnel walls up through the slab; the
walls between the classrooms sit on the slab rather than extend through
it.
7.1.2 Fre-Mitigation Radon Measurements
Initial radon measurements in the school were made in December 1990
by the Columbus Department of Health using E-Perms. These values are
shown in Table 7.1.1 and shown by location in Figure 7.1.3. During this
period the school average radon level was 11.1 pCi/L with a high reading
of 20.5 pCi/L in room 10. Follow-up charcoal canister measurements were
made the weekend of March 22-25, 1991, when the HVAC system was off. The
average radon level was 4.5 pCi/L with a high of 8.4 pCi/L measured in
the east tunnel. The results of the follow-up measurements are tabulated
in Table 7.1.1. The measurement numbers shown in this table refer to the
location of the CCs as shown in Figure 7.1.4. The measured values are
shown by location in Figure 7.1.5. The school average radon level for
those rooms tested was 4.5 pCi/L with a high reading of 8.4 pCi/L
measured in the East tunnel.
The weather was relatively mild during this measurement period, with
a high of 72°F and an average of 56°F. One would expect these mild
weather conditions to reduce the stack effect in the building. A reduced
stack effect would result in reduced radon entry compared to colder
weather.
7.1.3 Building Investigation
During the diagnostic visit March 4-8, 1991 it was concluded that the
major source of radon entry was via the supply air tunnel below the
hallways.
7.1.4 HVAC System and Pressure Differentials
The original building has 23 fan-coil units (FCUs) located in the
subslab utility tunnel. The utility tunnel runs under the corridors to
the east, west, and south, as shown in Figure 7.1.1. Supply air for the
FCUs is distributed to the tunnel by a central fan located in a fan room
adjacent to the tunnel. The OA supplied from the central fan ranges
from 0 to 100%. Air in the tunnel (supplied by the central fan) is then
supplied to each classroom by the FCUs. The air either passes through
hot water coils for heating or bypasses the coils. The air from each FCU
is then supplied to the classroom via a subslab duct which then
distributes the air through registers located along the outside walls of
the classroom. Return air from the classrooms passes through openings
in the classroom-to-corridor wall and into the corridor. The return air
is then pulled into a centrally located return air grille in the corridor
near the central fan (Figure 7.1.6). During normal building operation
(1 am to 6 pm) the central fan and the FCUs run continuously.
This type of HVAC system is sometimes referred to as a "face and
bypass" system. Although a number of schools in the Columbus area have
this type of system, it has not been observed by EPA in schools in other
parts of the country. Central HVAC systems with subslab supply and/or
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return air ductwork have, however, been observed in many of EPA's
research schools (1).
7.1.5 Diagnostic Measurements
Initial diagnostic measurements conducted in March 1991 indicated
that the utility tunnel and associated air distribution system were the
major contributing factors to elevated radon levels in the school. As
a result, the focus of this research project was on the effect of HVAC
system operational parameters on radon levels. PFE measurements were
also conducted as part of the diagnostics. These tests indicated fairly
good subslab communication except across foundation walls and across the
corridor (or across the tunnel).
Inspection of the building HVAC system indicated that the system
might not be operating per design. Reduced system maintenance due to
budget limitations probably contributed to this situation. To obtain
information on the current operation of the system, a local testing and
balancing company was hired to measure system airflows in May 1991. A
60 point traverse on the suction side of the central fan was made with
the fan set at its design of 550 revolutions per minute. Results showed
that the fan was running at 27, 264 cfm: 264 cfra above the design
specification of 27,000 cfm. The results of the airflow measurements
(actual measurements) for all 23 FCUs, together with the design airflow,
are shown in Table 7.1.2. These measurements show that, although the
overall airflow for the 23 FCUs is only 233 cfm above design, there is
wide variation from design for most of the individual units.
During the following winter (1991-92), CPS maintenance personnel
adjusted the FCUs to their original design airflow (third column of Table
7.1.2) . The central air handling fan was set to maximum opening position
with no change in operating speed and locked in place. Total air flow
under 100% return air was later measured to be approximately 29,400 cfm.
These adjustments of the HVAC fans helped to reduce the depressurization
in the tunnel. School maintenance personnel also applied two coats of
paint to the tunnel walls and caulked all floor and walls cracks in the
tunnel. The authors were not informed of these changes (adjustments to
the HVAC system and sealing of the tunnel) beforehand and, as a result,
were not able to quantify the effect of the individual changes on radon
levels.
During the spring of 1991, the school was instrumented with a
toil L-LilUOUfa Qaua-LOMMwL Iv IcwUXUi
• radon concentrations (eight locations)
• differential pressure (seven locations)
• temperature (seven locations)
• percent open of return and outdoor air dampers {central fan)
• weather (humidity, wind speed and direction, rainfall)
The exact locations of the parameters measured are shown in Table 7.1.3.
Initial plans were to collect data during the spring of 1991 with the
central HVAC fan supplying specified quantities of OA, The test matrix
for these measurements is shown in Table 7.1.4. Unfortunately, school
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officials were unable to adjust the OA damper as required for the
testing, so testing was delayed until the winter of 1991-92.
Note that the percent open of the return air and outdoor air dampers
in this report refers to the actual damper position. Actual airflow
would be expected to be a non-linear function of the damper position.
However, to a first approximation this can be treated as a linear
function. Another method of estimating the percentage of outdoor air in
a mixed air stream is through measurements of the stream temperatures.
Figure 7.1.6 shows the correlation of the OA damper position indicator
with the percent OA calculated using the following formula:
0A{%)= )T"Sx~Jtm\ xlOO.
Where Tmix is the temperature of the air in the mixing chamber immediately
upstream of the return air fan, is the temperature of the air in the
return duct, and Tout is the outdoor air temperature. The correlation
equation shown in Figure 7.1.6 indicates that even with the OA Damper
closed there is approximately 5% OA leakage, and at 50% damper opening
there is only about 43% OA entering the system. Attempts to directly
measure the RA and OA flows at 50% damper opening were unsuccessful.
7.1.6 Mitigation Strategy
The intent of the investigations at this school was to determine if
the HVAC system could be used as a radon control technique by increasing
the OA intake into the building.
7.1.7 Effect of OA Damper Position on Radon — Before Adjustments
Data were collected for the test matrix both before and after school
personnel adjusted the HVAC system and sealed the tunnel. Figures 7.1.7
and 7.1.8 show the effect of the OA damper position on radon levels in
the school. These data were collected prior to adjustments to the HVAC
system and sealing of the tunnel; however, it is possible that some of
the work was initiated during the final test (with 100% OA) . Since
school officials did not inform the researchers of the work until it was
underway, the exact timing is not known.
Figure 7.1.7 shows radon levels in five classrooms and the teacher's
lounge; Figure 7.7.8 shows radon levels in the west and east tunnels.
The average radon levels during each of the three test conditions in
Table 7.1.4 (100% return air, 501 return air/50% OA, and 100% OA) were
calculated from the continuous data collected during the test condition
and are displayed in Figure 7.1.9. Three conclusions are apparent from
these data:
(1) With 100% return air, average radon levels are much higher than
the previous pre—mitigation E—Perm and charcoal canister
measurements, averaging over 20 pCi/L.
(2) Average radon levels in the six rooms (Figure 7.1.7) closely
track radon levels in the tunnels (Figure 7.1.8) . The levels in the
rooms tend to be slightly lower than in the tunnels, supporting the
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assertion that the tunnels are the primary source of radon in the
school.
(3} Radon levels are reduced by about 75% when the OA damper
position is increased from 0 to 50%, No additional reduction is
observed when the OA damper position is increased from 50 to 100%.
However, the data collected during the 50% return air/50% OA damper
conditions are limited to a 24 hour test and, thus, should be
interpreted cautiously,
(4) Although radon levels are reduced by about 75% when the OA is
increased to 50 or 100%, average radon levels in the classrooms
still exceed 5 pCi/L,
7.1.8 Effects of OA Damper Position on Radon -- After Adjustments
The test matrix was then repeated after school maintenance personnel
adjusted the KVAC system to design specifications and painted the tunnel
walls. The results from these tests are shown in Figure 7.1.10. These
data show similar trends in radon levels as B^xgures 7,1,7, 7.1.8, and
7.1.9 (before adjustments}. However, average radon levels are about 6
pCi/L lower in the west tunnel and 1 pCi/L lower in the east tunnel after
sealing. These reductions in tunnel radon levels are also reflected in
the room radon levels. During the test run with 50% return air/50% OA,
radon levels in the rooms average about 4 p'Ci/L. When the OA is
increased to 100%, average radon levels in the classrooms are about 2.5
pCi/L.
Figure 7.1,11 summarizes the average radon levels in the two tunnels
and six rooms after adjustment of the HVAC system and sealing of the
tunnel. The percent reduction attributed to these changes is shown above
each bar. All reductions exceeded 10%, with a high of 57% reduction when
100% outdoor air was supplied.
Prior to these adjustments, the differential pressure between the
tunnel and the outdoors was negative to neutral (depending on the percent
OA) . After the HVAC system was adjusted and the tunnel sealed, the
differential pressures under all three OA conditions were relatively
neutral. This reduction of negative pressure reduced radon entry into
the tunnels and, consequently, radon levels in the school.
7.1.9 Estimated Costs
It is obvious that operation of the HVAC unit in this school at an
increased OA intake will result in increased energy costs. Also, since
the HVAC system does not include a pre-heat unit, the comfort of the
occupants is likely to decrease during weather extremes unless more
energy is consumed to overcome the cold OA intake. The exact increase
in energy costs were not estimated in this study.
7.1.10 Summary
Data from this school showed that radon levels could only be reduced
from above 20 pCi/L to below 4 pCi/L when the HVAC system was adjusted
to its design specifications, 100% OA was supplied to the central fan,
and tunnel walls were sealed. Although radon reductions were about 75%
prior to adjustment of the HVAC system and sealing of the tunnel, levels
were not reduced to below 4 pCi/L even with ,100% OA, Data from other
schools discussed in this report support the conclusion that it is
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difficult to reduce radon levels from above 20 pCi/L to below 4 pCi/L
using only the HVAC system.
The research project in this school indicated that, when 100% OA is
introduced and major radon entry routes are sealed, radon reduction with
the HVAC system is consistent.' However, school personnel indicated that
this condition xs difficult to achieve during extremely cold weather due
to concern with energy costs. Similar observations have been made in
other research schools, particularly in schools with UVs.
Other building components were not monitored in this study. However,
research in other schools has shown that (a) opening the classrooin~to~
corridor door affects classroom radon levels (may increase or decrease
depending on the school), and (b) operation of exhaust fans may increase
or decrease classroom radon levels depending on the building.
7.2 SULLIVANT ELEMENTARY SCHOOL
This school was selected to replace Fifth Avenue as a school in which
to install the data logging system in order to study the manipulation of
the HVAC system for radon control. This building is located at the
southern edge of the city in an alder and industrial area.
7,2,1 Building Description
The original part of this building has a two fan (supply and return)
air handling system and adequate provision for the addition of OA to the
delivery fan. Conditioned air is supplied to the classrooms through a
ducted system above the ceiling in the hall. The return air is carried
back to the return air fan through a subslab tunnel the width of the hall
and about four feet high. Sidewalls of the tunnel are concrete block and
are not coated on either side. The concrete tunnel floor has an
occasional'crack and obvious floor to wall cracks. Because the tunnel
operates under negative pressure it was thought to be the primary radon
source. Radon levels under the room slabs and the slab of the tunnel
were moderately high and could readily explain the relatively high radon
levels found in the building.
In addition to the return air tunnels, the building has subslab
utility tunnels along the outside walls to carry hot water to fin heaters
located under the windows in the classrooms. These tunnels are open to
the boiler room and in some places were connected to the return air
tunnels. They could also be a source of radon entry although radon
levels under the slab of the utility tunnels were not as high as under
the return air tunnel slab.
A four room addition to the building has the same type of HVAC system
(but on separate fans) and was included in the study. The other
additions to the building have different HVAC systems and were not part
of the study.
Examination of the architectural drawings for this building showed
subslab barriers on all sides of all rooms and the use of "pit-run"
gravel as the fill under the slab. According to the drawings, the gravel
was more than a foot thick under some of the building. Measurements of
the PFE found moderately good communication under the slabs and it was
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possible to pull negative pressures through at least one of the subslab
barriers.
7.2,2 Building Investigations
Continuous data logging equipment was installed in this school in
March 1991 and remained until January 1992. During this eleven month
period numerous attempts were made to obtain meaningful data on the radon
levels and operation of the HVAC system. In every case the results were
questionable due to uncertain operation conditions. The staff at the
school refused to cooperate in the research study and in fact restricted
the entry and operation of the building. It was finally decided to drop
this, school from the study as the equipment was needed in other
locations.
7.3 FIFTH AVENUE ELEMENTARY SCHOOL
This school is located in the central part of Columbus adjacent to
the Ohio State University campus. The building was originally visited
on December 13, 1990 and again during a diagnostic visit March 4-8, 1991.
7.3.1 Building Description
This school was built in 1975 and is air-conditioned and heated with
heat pumps located on .the roof of the building. It was originally
thought that this school would be good candidate for either ASD or
mitigation through use of the HVAC systems. The building has a minimum
of subslao barriers and indications of good aggregate under the slab.
7.3.2 Pre-Mitigation Radon Measurements
The initial radon screening measurements were carried out at a total
of 29 locations in the school. All of these values were above 4 pCi/L
with an average level of 8.7 pCi/L and a high reading of 13,9 pCi/L.
7.3.3 Building Investigations
The building plans call for aggregate underneath the slab and
indicate that subslab barriers are located in the restroom and storage
area near the library. The only other subslab barriers separate the
classroom area from the multi-purpose room, utility room, and the front
office area. PFE measurements were conducted in the classroom area and
in the multi-purpose room and are discussed separately below.
7.3.4 HVAC System and Pressure Differentials
The HVAC system for this building consisted of a forced air system
using water-source heat pumps, one AHU for each occupiable room in the
building. Return air was ducted above the ceiling. OA was provided
though duct penetrations in the roof, each penetration was manifolded to
serve 4 to 6 AHUs. The OA supply was not fan powered, relying on near-
equal pressure drops in the return and outdoor duct work to draw in OA.
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7.3.5 Diagnostic Measurements
Air volume measurements made in one OA supply (serving two classrooms
and half the library) indicated only 70 cfm of OA. Assuming 25 students
per classroom, and no students in the library, each student is receiving
about 1.2 cfm of OA, which is 8% of the ASHRAE recommended standard of
15 cfm per student for occupied classrooms (4).
Pressure measurements in the building indicated the interior to be
at a negative pressure with respect to the outdoors, when the exhaust
systems were turned off and when they were on. With exhaust systems on
(three sets of boys and girls toilets, and an art room), the hallways
were -0.015 to 0.030 in. W. C. with respect to outdoors. With these
exhaust systems off, interior pressures were -0.010 with respect to
outdoors.
The evidence suggests that the HVAC system is not pressurizing the
building, and measurements indicate that the existing system cannot be
operated so that pressurization occurs. Pressurization might be
accomplished with the addition of fans in the OA supplies.
A 1.5 in. suction point for the PFE measurements was located in the
office area next to the library, and six 0.5 in. test holes were drilled
at distances from 1 to 71 ft from the suction hole. The results of these
PFE measurements are summarized in Table 7.3.1. Although negative
pressures were only observed at two of the test holes (b and g),
measurements at three of the other test holes indicated that the subslab
area became less positive relative to the building interior when a vacuum
was applied to the suction hole, an indication of communication.
Additionally, points c and d were located near the outside wall, and it
is likely that leakage was occurring due to the large floor/wall crack
along most of the building perimeter. Subslab sniffs in these two test
holes near the outside wall were much lower than the interior test holes,
indicating that some dilution was occurring.
The measurement at test point g was repeated using a fan for suction
rather than the vacuum and the same results were observed. It is
expected that the PFE in the classroom area will be greatly increased by
excavating a large suction pit and using an appropriate fan since
communication was observed at five of the six rest points (all but test
point f).
The suction point in the multi-purpose room area was located in the
storage area with one test hole located at the far end of the multi-
purpose room and the other test hole located in an adjacent closet that
is surrounded on three sides by footings. As seen in Table 7.3.2, a
slight depressurization was observed at both test points.
7.3.6 Mitigation Strategy
During the visit in March it was discovered that the amount of OA to
the HVAC could not be increased hence it was decided that only minimal
information could be obtained by installation of a datalogging system in
this school. Further examination of the design drawings indicated that
with the existence of aggregate under the slabs and only a minimal number
of subslab barriers an ASD system was the preferred mitigation system.
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PFE measurements made at this time indicated good communication under the
slabs. It was anticipated that the 20,000+ ft2 classroom wing could be
mitigated with a minimum number of suction points.
7.3.7 Mitigation System Details
A suggested mitigation system was developed and forwarded to CPS as
follows. It was recommended that two ASD points be installed, one at
each suction point location used in the PFE measurements discussed above.
It is possible that two additional points may be needed, one in the
classroom area (in the vicinity of test point f) and one in the front
office area. However, initially it is recommended that only two points
be installed since it is possible that they will provide adequate ASD
(particularly in the classroom area).
A separate fan should be used for each of the two ASD points. The
fan in the classroom area should be an in-line fan capable of moving 410
cfm at 1 in. VI.C., and the fan in the multi-purpose room should be
capable of moving 230 cfm at 1 in. W.C. For the system in the classroom
area, the drops to the suction points and the overhead piping should be
6 in. diameter PVC piping. There is adequate space in the classroom area
dropped ceiling to run the overhead piping. For the system in the multi-
purpose room area, 4 in. diameter PVC piping should be used for the
suction point and 6 in, diameter PVC piping should be used overhead. A
tee should be installed in the overhead piping for each of the ASD
systems to facilitate addition of suction points if needed.
The suction pits under each ASD point should be excavated to a
minimum diameter of 36 in. and a minimum depth of 12 in. to enhance PFE.
A coupling joint should be used when inserting the suction pipes into the
cored holes in the slab. Care should be taken to ensure that the suction
pipe does not drop into the soil at the bottom of the excavated pit. The
coupling assures this if the proper size core is drilled (4,5 or 5 in.
for 4 in. pipe, and 6,5 or 7 in. for 6 in. pipe). An easily checked
pressure activated alarm should be installed on the piping for each
system to monitor system operation over time.
The fans should be located exterior to the school building and the
exhaust should be located at least 30 to 50 ft (check local codes for
exact distance) away from any outdoor air intakes, windows, or doors.
The roof contains several outdoor air intakes, thus caution should be
used in selecting the ASD system's exhausts. It is recommended that the
fan be placed on the side of the building away from the playground. All
local and state building codes should be carefully followed. These
include; electrical wiring specifications for the fans (such as using a
separate circuit breaker and weatherproof conduits outside the building),
and the use of materials that cut off fire if the PVC pipes penetrate a
designated fire wall. (This does not appear to be the case when exiting
the piping from this school.)
7.3.8 Additional Diagnostics and Mitigation
Once the mitigation systems are installed, two sets of short-term
radon measurements should be carried out, one with the ASD systems off
and one with the systems operating. Since radon levels can vary
substantially over seasons, these should provide an accurate assessment
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of system performance. The measurements should be made in all normally
occupied rooms.
If radon levels are still elevated, an effort should be made to seal
the large (at least 1/8 in. in some places) floor/wall crack located
around much of the building perimeter. Radon sniffs below the slab at
the floor/wall crack ranged from about 60 to 500 pCi/L. This indicates
that the crack is probably a major radon entry route since the perimeter
is approximately 580 lineal ft. Polyurethane caulking should be used,
and manufacturer's instructions should be followed for proper surface
preparation. Since the crack appears to be rather deep in some areas,
it may be necessary to use backerod beneath the caulking. Because of the
effort involved in sealing this crack, it is first recommended that the
ASD system be evaluated without sealing. The system may perform
adequately without sealing and, if it does, the leakage will increase OA
entry into the classrooms which would improve ventilation.
7.3.9 Estimated Costs
If the ASD systems are installed by CPS personnel experienced in
radon diagnostics, estimated person hours would be approximately 40 hours
(not including the sealing). It is estimated that materials -- fans,
piping, fittings, etc. -- will cost about $2000.
7.4 HUBBARD ELEMENTARY SCHOOL
This school is located in the central part of Columbus near Fifth
Avenue Elementary described above. The building was originally visited
on December 13, 1990 and again during a diagnostic visit March 4-8, 1991.
7.4.1 Building Description
This three story building was constructed in 1892. The ground floor
is about 3 ft. below grade level and contains classrooms as well as
storage areas, a boiler room, and fan room. The fan room has a very
large air handling fan which, when operating, causes the room to be under
extremely negative pressures relative to the ambient pressures outdoors.
There is a slab-on-grade multi-purpose room which was added to the
original building in recent years. No design drawings are available for
the original building except for remodeling plans which describe the KVAC
system.
7.4.2 Pre-Mitigation Radon Measurements
The initial radon screening measurements were carried out at 19
locations on the ground floor. Of these, 17 values were above 4 pCi/L,
The average of these measurements was 14.7 pCi/L with a high reading of
42.7 pCi/L.
7.4.3 Building Investigation
Hubbard is representative of many schools built around the turn of
the century in Columbus and elsewhere. The CPS has approximately 12 of
these still in use and it was anticipated that Hubbard would be an
excellent choice to research. Because of design, these old school
buildings are expected to be difficult to mitigate.
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7.4.4 HVAC System and Pressure Differentials
During the March visit it was found that the building has a central
air handling system that was installed in 1950 with previsions for OA.
7.4.5 Diagnostic Measurements
Although no plans were available for the original building, it was
assumed that no aggregate was placed under the slabs during construction
(a common practice according to experts). However, a moderate amount of
PFS was found and it is believed that ASD will work with one suction
point in each ground floor room. While making the PFE measurements it
was found that the lower floor was under about 0.03 in. W.C. negative
pressure for no apparent reason.
Further examination of the building disclosed that it had a very high
pitched roof with an attic which was about thirty ft tall with a dome on
top of it. Stairs led to the dome which was found to have large openings
on all four sides. The dome was floored, had a door over the steps, and
had a large set of power louvers in the dome floor which were wide open
(and looked like they had not been closed in a very long time). A stack
effect (60 to 75 ft of height) was causing the severe depressurization
of the ground floor.
7.4.6 Mitigation Strategy
An attempt was to have been made to interrupt the stack effect before
any mitigation is attempted on the building. It is believed that the
floor of the dome can be sealed in such a way that the stack effect can
be minimized. However, due to unforeseen circumstances, no attempt was
made by CPS to decrease the stack effect in the building.
7.4.7 Summary
This building is typical of several buildings in the Columbus (and
probably other) School District(s) . These older buildings are
characterized by lack of (or incomplete) design drawings and inoperative
HVAC equipment. The pre-mitigation diagnostic visit is crucial to
developing an effective mitigation system that takes into account the
various idiosyncrasies of the building and its operation.
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SECTION B
SOUTH DAKOTA SCHOOL
Initial radon measurements (11) in the Rapid City Area School
District (RCASD) were made from November 1990 to February 1991 using
ATDs. Based on these results, eight schools were identified by AEERL as
potential research schools. The results from the ATD measurements at
these schools are summarized in Table 8.1.1. The overall average radon
level in all of these school buildings was 8.2 pCi/L. Abraham Lincoln
Elementary school had the highest average level of 18.8 pCi/L and
Grandview Elementary had the lowest average level of 4.9 pCi/L. Based
upon these results, Lincoln Elementary was selected as having the highest
priority for research. The other schools listed in Table 8.1.1 will not
be discussed further in this report.
8.1 ABRAHAM LINCOLN ELEMENTARY
This school is located in western Rapid City on a hill side of
exposed and crumbling shale.
8.1.1 Building Description
The original building was constructed in 1951 with 10 classrooms, a
cafeteria/gym, and several offices and special purpose rooms. The
original building had approximately 14,280 ft2. Three classrooms and a
library were added to the west side of the original building in 1957,
increasing the total area to 22,132 ft2. The plan of the building is
shown in Figure 8.1.1. The circled numbers are the measurement locations
described below.
8.1.2 Pre-Mitigation Radon Measurements
The initial radon screening measurements were carried out over the
period from November 1 , 1990 to February 5, 1991 as shown in Table 8.1.2.
The results of these measurements by location is shown pictorially in
Figure 8.1.2 The highest level measured was in room 16 (36.7 pCi/L) and
the lowest value (7.9 pCi/L) was in room 4. The average radon level in
all rooms tested during this time was 18.8 pCi/L.
A second set of screening measurements were made May 3-17, 1991 using
CCs. The CCs were placed and retrieved by RCASD personnel. The results
are tabulated in Table 8.1.2 and shown by location in Figure 8.1,2. The
values circled are the Winter 1990-91 ATD results; those in parentheses
were made with the building closed and all UVs off over the weekend of
May 3-5, 1991; the final set of measurements in Figure 8.1.2 were made
with the building closed and the UVs operating over the weekend of May
17-19, 1991, The school average with the UVs off was 10.9 pCi/L with the
highest value of 35.6 pCi/L measured in room 16 and the lowest value of
1.3 pCi/L in room 9. With the UVs turned on the school average dropped
to 5.7 pCi/L with the highest value of 14.1 pCi/L measured in room 16 and
the lowest value of 0.6 pCi/L in room 12.
These measurements are compared in Figures 8.1.3 and 8,1.4 where the
three sets of values are plotted for each room or location (note that not
all the rooms were tested during the Winter 1990-91 ATD measurements).
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The radon levels when the UVs are on compared to when they are off is
shown in Figures 8.1.5 and 8.1.6. In half of the rooms (Rooms 1, 3, 11,
13, 16, and in the office, gym, principal's office, teacher's lounge, and
the health room) the radon levels dropped with the UVs on compared to the
levels measured with the UVs off. This would be expected because of the
OA provided by the UVs. In the other rooms the levels increased with the
UVs operating (rooms 9, 18, 20 and the boiler room showing the largest
increases). The increases in these classroom radon levels are thought
to be due to closed or inoperable OA intake dampers in those rooms. As
mentioned previously, the UVs were repaired prior to the continuous
datalogging. The higher radon level in the boiler room might be due to
increased depressurization with the UVs operating.
The OA temperatures were significantly different for the two
measurement periods so these data should be interpreted cautiously. Over
the period May 3-5, 1991 (UVs off) the average high and low temperatures
were 46.7 and 31.7°F, respectively. Over the period May 17-19, 1991 (UVs
on) these average temperatures were 67.3 and 47.3CF. These large
temperature differentials during the two charcoal canister measurements
make comparison of the relative influence of the UVs difficult.
8.1.3 Building Investigation
The design drawings indicate that the original building has below-
grade, poured concrete, foundation walls around the perimeter of the
building and under the corridor walls but not between the classrooms as
shown in Figure 8.1.7. The foundation walls penetrate the slabs" along
the exterior walls and the corridor walls. The slabs are poured on
compressed soil covered with a minimum of 6 in. of gravel. The addition,
rooms 17-20, has a subslab utility tunnel along the outside walls as
shown in Figure 8.1.7. However, because of the lower radon levels in the
addition, it was not included in this research project.
Floor/wall cracks were observed in many of the classrooms and are
thought to be a major contributor to radon entry. Unfortunately cabinets
and closets typically surround three of the four walls in each classroom
(the fourth wall is the chalkboard) making access to and sealing of the
floor/wall cracks difficult. One crack observed in room 16 — a corner
room with both the highest ATD (36.7 pCi/L) and followup measurements
(35.9 and 14.1 pCi/L) -- was about 0.5 inch wide.
Each classroom has a UV for heating and ventilating. The units are
located along the outside wall. Most of the classrooms also have a fan-
powered exhaust located in the closet along the wall parallel to the
corridor.
8.1.4 Diagnostic Measurements
On May 1, 1991, C02 measurements were made in most of the rooms. The
measurements, in most cases, were made while the rooms were occupied and
the hall doors were open. The C02 concentrations shown in Table 8.1.3
ranged from 700 to 4000 pprr. with an average value of 1687 ppm. Because
ASHRAE (4) recommends CO;, levels below 1000 ppm the researchers
recommended that school personnel make the necessary repairs to bring the
UVs up to design specifications. This was before continuous datalogging
began.
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During the week of 30 July 1991 an intensive diagnostic evaluation
was carried out at this school building (in addition to the other seven
schools in Rapid City). During this evaluation, measurements of the
subslab radon levels, the PFE under the slab, UV operation, and other
items of interest were carried out.
8.1.5 HVAC Systems and Pressure Differentials
Measurements of UV airflows and differential pressures across the
building shell were made in July 1991. The measurements were taken under
various building operating conditions in all classrooms in the original
building:
• UV speed (high, medium, and low)
• UV outdoor air damper (completely open and completely
closed)
• closet exhaust systems (on and off, each room)
• room-to-corridor door position (open and closed)
For these spot measurements the greatest negative pressure
differentials across the building shell occurred when the hallway door
was closed and the exhaust fan on. With the UV outdoor air damper open
and the exhaust fan operating, the differential pressure for the
classrooms averaged -0.022 in. W.C. The differential pressure averaged -
0.032 in. W.C. with the UV OA damper closed.
Operation of the exhaust fans (one for each room) had a dramatic
effect on the pressures in the room and tended to override any
pressurizing abilities of the UVs. The total exhaust measured for the
10 classroom fans was 5,554 cfm while the maximum OA capability of the
UVs totaled 1,590 cfm — 3.5 times more exhaust than supply. The exhaust
fans are new and draw 630 to 1,021 cfm per room, compared to the old fans
that exhausted about 100 cfm per room.
Opening the hallway doors tended to have a neutralizing effect on the
classroom differential pressures. The negative pressures caused by
exhaust fan operation were near zero when the hallway doors were open.
The UVs were able to pressurize the rooms on average, 0.003 in. W.C.
with the exhaust fan was off and the hallway door closed. A positive
pressure was also observed when the UVs were on, the exhaust fan was off,
and the hallway door was open.
The subslab radon levels obtained are shown in Table 8.1,2 and shown
by location in Figure 8.1.8. In this figure the point labeled Fa is the
point suction was applied during the subslab PFE tests. As shown in
Table 8.1.2, the subslab radon levels averaged approximately 4260 pCi/L
with the highest level of 6600 pCi/L measured under room 14. In general,
the source strengths were lower under the slabs in the East wing than
those under the North wing of the building. These levels correlate
somewhat with the winter ATD and the May CC measurements shown in Table
8.1.2.
Subslab PFE measurements were carried out using a 1.5 in. diameter
hole drilled through the slab in the closet of room 14 (in the north
wing) and also through a hole located in the closet of room 4 (in the
east wing). The pressure difference between the subslab and the
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classroom was then measured (as a minimum; at the center of each room.
The subslab PFE was found to be much better in the north wing than in the
east wing.
A computer based datalogger monitoring system was installed in the
school in July 1991. Remote monitoring of the school was carried out via
a telephone modem. Data were downloaded to a personal computer in
Birmingham, Alabama for data analysis and storage. This system monitored
the following parameters every 15 seconds and stored averaged (or in the
case of the radon monitors totalized) values every 30 minutes:
• Ten continuous radon monitors measured the radon
levels in rooms 1, 2, 3, 4, 9, 11, 12, 13, 14, and 16.
• Nine pressure transducers monitored differential
pressures between both the rooms ana the subslab areas
in rooms 1, 4, 13, and 16. These pressure
differentials were referenced to the pressure m the
hallway which in turn was monitored relative to
outdoor pressure.
• The temperatures in rooms 1, 4, 13, 16, the hallway,
and outdoors were monitored.
• The operation of the UVs in rooms 1, 4, 13, and 16 was
monitored. This included the on/off times and the
positions of the outdoor air dampers.
• The on/off times of the closet exhaust fans and the
position of the doors (open or closed) for rooms 1, 4,
13, and 16 were also monitored.
A weather station was used to continuously monitor
wind speed and direction and precipitation.
8,1,6 Mitigation Strategy
Because of the existence of the exhaust fans in the rooms and due to
uncertainty with regards to using UVs to control the radon levels it was
believed that ASD systems should be used in this school. The ASD systems
installed in this school are shown in Figure 8.1.9. As indicated in this
figure, suction points were placed in rooms 1 through 4 and in rooms 13
and 16, Because of the different PFEs in the two wings of the building,
the systems for the two wings are discussed separately.
8.1.6.1 Mitigation System Details - North Wing
The PFE in the north wing was better than that in the east wing. As
indicated in Figure 8.1.9 one suction point was placed on each side of
the corridor, because subslab footings separate the two areas. One point
was placed in room 14 (to treat rooms 12, 16, the teacher's lounge, and
the health clinic) and one point was placed in room 11 (to treat rooms
9, 13, and the office areas). At each suction point a 8 in. diameter
hole was cored through the slab and a pit was excavated in the soil about
36 in. in diameter and approximately 12 in, deep. Both systems use 8 in.
diameter, Schedule 40 PVC piping for both vertical and horizontal runs.
Each suction point uses a fan rated at approximately 300 cfm at 1 in.
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W.C, The fans are located on the roof, with the exhaust directed
vertically upward.
8.1.6.2 Mitigation System Details - East Wing
Because of the poorer PFE measured during the diagnostic testing in
the east wing, one suction point was installed in each of the four rooms.
The overhead piping for rooms 1 and 2 and for rooms 3 and 4 were
manifolded together so that only two fans were needed. In rooms 1 and
3, the piping was run from the rooms and manifolded above the hall
ceiling tile, A single pipe then ran across the hall and up through the
chase above the closets in room 4. The piping from room 2 was run across
the bathrooms and joined to the piping from the suction point in room 4.
A single pipe was then run around the room to exit through the chase
above the closet. In the top of the chase the pipes exited the building
through an old window opening (now closed with plywood).
Because of the lower PFE, the fan flow rate is expected to be much
lower than that in the north wing. Also, a fan capable of a higher
pressure head was anticipated. Due to the low flowrate and high pressure
expected in these east wing systems, the piping used was much smaller in
diameter than the systems in the north wing. All piping in this wing was
2 in. diameter, Schedule 40 P7C. At each of the four suction points, a
5 in. diameter hole was cored through the slab to enable the installers
to hand excavate a pit in the soil under the slab. The suction pits were
about 36 in. diameter by about 12 in. deep. The fans used in this wing
were caoable of moving roughly 25 cfm at a static pressure of around 30-
35 in. *W.C.
8.1.7 Results Of Initial Mitigation System
The test matrix used to evaluate both the UVs and the ASD system's
effects on radon is shown in Table 8.1.4. Testing occurred November 18,
1991, through January 31, 1992, The results of this series of tests are
summarized in Figures 8.1.10, 8.1.11, 8.1.12, and 8.1.13 for rooms 1, 4,
13, and 16, respectively. In each of these figures the results are shown
first (left) with the ASD off to evaluate the UV alone and second (right)
with the ASD operating to evaluate both ASD alone and ASD in conjunction
with the UVs. The results with the ASD system off are discussed first,
followed by a discussion of the results with the ASD system on.
Room 1 was the only classroom with a door directly to the outdoors.
In Figure 8.1.10 it is quite evident that opening the outside door was
very effective in lowering room radon levels. However, this approach is
not recommended as a practical year-round approach to radon control. It
is interesting to note that opening the hall door also lowered the radon
levels for all modes of operation of the UV and the exhaust fan. In
fact, the radon levels in all four rooms decreased when the hall door was
open. This was most likely the result of increased ventilation and
consequent dilution of the radon concentrations. There may also have
been some pressure neutralization thereby reducing the driving force for
radon entry.
With the ASD systems off (left-hand graphs in Figures 8.1.10, 8,1.11,
8.1.12, and 8.1,13) operation of the closet exhaust fans without the UVs
resulted generally in either lowering the radon levels or having little
effect. One exception is seen in the left side of Figure 8.1.11 where
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operation of the exhaust fan in room 4 with the hall door open actually
increased the radon levels. Other research has shown that operation of
exhaust fans can either decrease or increase radon levels, depending on
the relative leakage between above grade (decreases radon levels through
infiltration of outdoor air) or below grade (increases radon levels
through infiltration of radon-containing soil gas).
Operation of the UVs (with ASD and exhaust fan off) reduced the radon
levels in rooms 1, 4, and 16 by about 10%. However, UV operation
increased the levels in room 13 by approximately 25%. These results are
not consistent with the CC results obtained in May 1991 (shown in Figure
8.1.6). However, during the period that these continuous radon
measurements were taken (November 1991 to January 1992) the average
outdoor high and low temperatures were 44.2 and 19. 90F, considerably lower
than in May, 1991 resulting in less OA supplied through the UV dampers.
It is possible that the UV in room 13 pulled radon from the floor/wall
crack, distributing it to the room and increasing the radon levels.
With the ASD systems operating (the right-hand graphs in Figures
8.1.10, 8.1.11, 8.1.12, and 8.1.13), the average radon levels in all
classrooms dropped to less than 3 pCi/L and in some cases to less than
1 pCi/L. The percent reductions ranged from about 80 to 99% with an
average reduction of about 901. These reductions appear to be fairly
independent of the mode of operation of the UVs and exhaust fans,
indicating that ASD and HVAC together did not outperform ASD alone.
Thus, while the UV and exhaust fan operation may lower the radon levels
in many of the classrooms, the levels were not consistently reduced to
below 4 pCi/L, Only the ASD systems effectively and reliably maintained
radon levels below 4 pCi/L.
8.1.8 Addit ional Phases of Diagnostics and/or Mitigation
The suction pressures at the suction points in rooms 1, 2, 3, and 4
were measured to be -0.24, -0.14, -0.27, and -0.10 in. W.C. and at the
high pressure fan inlets the suction pressure was measured to be
approximately -0.03 in. W.C. for both fans. These results indicated that
the fans were running at maximum air flow (about 50 cfm for each fan).
This indicated that the subslab communication was much better using the
installed ASD systems than was indicated during the diagnostic tests
using the vacuum cleaner technique. The two high pressure fans were
replaced in June 1992 with a single fan capable of moving 95 cfm at 1 in,
W.C, The radon levels in rooms 1, 2, 3, and 4 with the new fan operating
were essentially the same as with the two high pressure fans. The new
fan not only uses less energy (70-150 watts as compared to 180-320 watts
each for the other fans) but also is not as susceptible to failure during
down times as the high pressure fans.
8.1.9 Final Radon Levels
Upon the completion of this research (summer 1992), the radon levels
were averaging about 1 pCi/L as measured with the datalogger. However,
ATD measurements the following winter exceeded 4 pCi/L in the wing where
the high suction fans - had been replaced (east wing) . This led
researchers to the conclusion that subslab PFE had deteriorated due to
increased rainfall during this time period. As a result, the two high
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suction fans were reinstalled in this wing. School officials plan to
remeasure radon levels in this wing during the winter of 1993-94.
8.1.10 Estimated Cost
Costs for the Schedule 40 PVC piping, PVC elbows and fittings,
sealants, and miscellaneous parts were on the order of $1,200. The costs
for the four fans were $390 for each of the two low pressure fans and
$1,425 for the two high pressure fans. Other supplies (e.g. electrical
wire and fittings) had a total cost of approximately $3,500.
Installation of the ASD systems used on the order of 10 person days total
{2 people x 5 days).
8.1.11 Summary
In this school, Lincoln, the UVs alone were not able to consistently
maintain radon levels below 4 pCi/L. The exhaust fans and the opening
of the classroom-to-hallway doors had varying effects on radon levels.
The ASD systems, however, provided excellent radon control, even better
than that predicted during the diagnostic tests. Operation of the UVs
together with the ASD system did not provide much additional radon
reduction over the ASD system alone.
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SECTION 9
TENNESSEE SCHOOL
9.1 GLENVIEW ELEMENTARY SCHOOL
School buildings that are constructed over crawl spaces can present
unique challenges to radon mitigation since they are often quite large
fat least 4,000 ft2 in area) and may contain support walls with footings
that extend below the soil surface. The perimeter walls in the crawl
space can also be extensive (on the order of 500 to 1,000 lineal ft).
In this research project, natural ventilation using the existing vents
in the foundation walls, depressurization and pressurization of the crawl
space, and ASD under a polyethylene liner covering the soil were compared
in a wing of a school building in Nashville, Tennessee. The wing has
four classrooms constructed over a crawl space area of 4,640 ft2. The
building and crawl space were monitored throughout each mitigation phase
with continuous sampling devices that recorded radon levels both in the
crawl space and in the rooms above, in addition to environmental
conditions such as temperatures and pressure differences in the building,
9.1.1 Building Description
This 29,266 ft2, Nashville school building (13) was originally
constructed in 1954, with subsequent additions in 1957 and 1964. The
original building and the first addition are slab-on-grade construction,
and the 1964 four-classroom addition is constructed over a crawl space
connected to the slab-on-grade section by a walkway.
9.1.2 Pre-mitigation Radon Measurements
Initial charcoal canister measurements in this school in 1989
indicated that the 18 slab-on-grade rooms measured presented the most
severe radon problems, averaging 34.1 pCi/L with a standard deviation of
7.5 pCi/L. In fact, levels over 100 pCi/L were subsequently measured in
some of the slab-on-grade rooms. Radon levels in the four classrooms
constructed over the crawl space were relatively much lower, averaging
9.7 pCi/L with a standard deviation of 0.7 pCi/L. As a result, initial
remediation efforts during the summer of 1989 focussed on reducing levels
in the slab-on-grade wings with ASD (2, 8). Post-mitigation measurements
during February 1990 indicated that levels in the slab-on-grade rooms
averaged below 2 pCi/L, and at this time plans were initiated to research
the effectiveness of various mitigation techniques in the crawl space
wing.
9.1.3 Building Investigation
The crawl space is approximately 4,640 ft2 in area, and the height
ranges from 46 to 80 in. with a total air volume of approximately 25,500
ft3. The plan view of the crawl space is shown in Figure 9.1.1. Access
to the crawl space is excellent and the surface of the soil is not
complex (i.e., no inaccessible areas, rock outcroppings, or large piles
of soil) . The floor of the classrooms over the crawl space is a
suspended concrete slab poured over corrugated steel sheets supported by
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a network cf steel trusses. There are two internal concrete block
support walls in the crawl space that extend below the soil. These walls
do not penetrate the slab overhead; however, the walls effectively
subdivide the crawl space into three sections, as shown in Figure 9.1.1.
This type of construction is quite different from that found in
residential houses. In many existing houses, the floor is composed of
wood decking (either 1 by 6 in. boards or plywood sheathing) supported
by wooden floor joists. This type of house construction has been shown
to be quite leaky and nearly impossible to seal all the openings between
the crawl space and the rooms overhead {14, 15). Construction of this
wing over a crawl space with a suspended concrete slab appears to be
typical for crawl space schools as more of these have been seen than any
other type. Wood floor construction is rare.
9.1.4 HVAC System and Pressure Differentials
Since the crawl space does not contain any ductwork or any asbestos,
it was of interest to determine if the crawl space in this school
building could be sealed well enough to permit pressurization or
depressurization of the crawl space volume as a mitigation option.
9.1.5 Diagnostic Measurements
The crawl space is ventilated naturally with eight block vents (four
each on the east and west sides of the building) . Each of these
foundation wall vents has a screened opening with the same gross area as
a concrete block (8 by 16 in.) or approximately 128 in.2 The results of
fan door leakage tests (shown in Table 9.1.1) carried out on the crawl
space resulted in an effective leakage area (ELA) at 0.016 in. W.C. of
pressure difference of 251 in.2 with the vents open and 83 in.2 with the
vents sealed (using closed-cell foam board and caulking). Thus, the
vents were providing approximately 168 in.2 of total open area, or about
21 in.2 per vent. This value is consistent with that measured in houses
using similar techniques (16). The important point is that the leakage
area (independent cf the block vents) is very low (83 in.2) compared to
that measured in 15 houses in the same geographic area which ranged from
198 to 424 in.2 with a mean of 262 in.2 (16). Thus, this building was
thought to be an ideal candidate to test a variety of possible mitigation
techniques.
9.1.6 Mitigation Strategy
Mitigation systems typically installed in crawl space houses include;
isolation of the crawl space from the rooms above, isolation and
depressurization or pressurization of the crawl space, isolation and
ventilation of the crawl space (either natural or forced), and ASD under
a plastic membrane — submembrane depressurization (SMD) covering the
exposed soil (10). Each of these mitigation techniques (with the
exception cf the forced ventilation) was tested in this school crawl
space in an effort to compare their effectiveness when applied to a
building having a larger size and a different construction type (concrete
slab over the crawl space).
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9.1.7 Results of Initial Mitigation (Spring/Summer)
Initial baseline testing was carried out before any modifications
were made to the building. Following the baseline measurements, the
accessible openings (e.g., utility penetrations) from the crawl space to
the upstairs rooms were sealed with a combination of closed-cell foam and
urethane caulking. The block vents were also sealed with rigid closed-
cell foam board and caulking. Following testing with the vents closed,
a network of 4 in. PVC ducting was installed as shown in Figure 9.1.1.
"The fan installed is rated at 200 cfm at 1.5 in, W.C. The fan and the
air distribution network were used to test the effectiveness of crawl
space pressurization and depressurization as mitigation options for the
building.
After the evaluation of crawl space depressurization and
pressurization tests were complete, two suction pits approximately 24 in.
in diameter and 12 to 18 in. in depth were excavated in each of the three
sections of the crawl space for a total of six suction pits as shown in
Figure 9.1.1. Each suction pit was covered with a piece of 36 in. square
by 1 in', thick marine grade plywood. The plywood covers were supported
at the corners by four common bricks. Both the suction pits and the
exposed soil were covered with two-ply high-density polyethylene
sheeting. The plastic film was installed in three pieces, one in each
section of the crawl space. No attempt was made to seal the plastic to
the outer or inner foundation walls. The edges of the plastic were cut
approximately 12 in. wider than necessary in the event that sealing to
the walls was necessary. The excess material was then simply folded up
the walls or allowed to fold back upon itself. The network of PVC
ducting was connected to the suction pits to complete the active soil
depressurization systems, as in previous house research (9) . A side view
of the SMD installation is illustrated in Figure 9.1.2.
Throughout the entire testing period, several parameters were
monitored continuously using a datalogger. The parameters monitored
include: pressure differentials between room 116 and outside the
building on the east and west sides; pressure differentials between room
116 and the crawl space interior; pressure differentials between room 116
and the sub-poly region during the SMD testing; temperatures outdoors,
in room 116, in the crawl space, and in the soil; wind speed and
direction; the outdoor relative humidity and rainfall; and the radon
levels in both Room 116 and the crawl space. Each of these parameters
was sampled every 6 seconds and averaged or totaled at the end of every
30 minute interval. These measurements and their locations are
summarized in Table 9.1.2.
The data were accumulated in the datalogging device and periodically
downloaded to a personal computer and stored on magnetic disks for later
analysis. A sample of this continuous data is shown in Figure 9.1.3
where the radon levels in both the classroom and the crawl space are
plotted for various conditions. Initial testing of the building began
on March 1, 1990, and continued through July 20, 19SQ, for a total of 152
days (3648 hours). The datalogger was reinstalled from December 18,
1990, to January 17, 1991, in order to evaluate the mitigation systems
during winter conditions. The most significant results are described in
the following sections for both the spring/summer and winter
measurements.
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9.1.7.1 Baseline Measurements
The baseline radon measurements made with the block vents open
averaged 5.1 pCi/L in room 116 and 10.8 pCi/L in the crawl space, as
shown in Figure 9.1.4. Figure 9.1.5 shows the averaged pressure
differences between the crawl space and outdoors and between room 116 and
outdoors during each phase of the mitigation. Also plotted in Figure
9.1.5 are the average testing period temperatures outdoors, in the crawl
space, and in room 116. Following closing and sealing of the block vents
and sealing the major openings between the crawl space and the classrooms
above, the average radon levels in the classroom increased by about a
factor of three to 17.1 pCi/L and the crawl space levels by a factor of
eight to 87.2 pCi/L. During this time the average pressure difference
in the classroom increased by a factor of about one and a half to - 0.019
in. W.C., and the crawl space pressure increased by a factor of almost
four to - 0.016. It is obvious that closing up the crawl space greatly
enhanced the depressurization produced mainly by the stack effect. Also,
the temperature differences between the interior of the building and the
outdoors were much larger than during the other testing periods, thus
increasing the stack effect. These results clearly indicate the effect
on radon when the crawl spaces vents are closed.
9.1.7.2 Crawl Space Pressurization
The next mitigation technique tested was crawl space pressurization
using the fan installed near the roof level of the building and the
network of PVC ducting to distribute the flow with the crawl space vents
closed. During pressurization, the average fan flowrate was 234 cfm
which was equivalent to about 0.6 air changes per hour EACH). During
this time the average crawl space pressure difference was reduced to -
0.006 in. W.C. and the average classroom pressure difference was reduced
to - 0.01 in. W.C, as seen in Figure 9.1.5. The average radon levels in
the classroom and crawl space were 10.6 and 29.1 pCi/L, respectively, as
shown in Figure 9.1.4. It is apparent that the flowrate of OA into the
crawl space is not sufficient to raise the pressure in the crawl space
above the outdoor pressure and could only negate about 60% of that
produced by the stack effect in the crawl space and about 50% of that
produced in the classroom. It is possible that by doubling the flowrate
(to around 500 cfm) the crawl space and the classroom could have been
pressurized above the outdoor conditions and the radon levels further
reduced. However, this option did not appear as a desirable year-round
solution because unconditioned air was being used for pressurization.
9.1.7.3 Crawl, Space Depressurization
Following the crawl space pressurization testing, the fan was
reversed so that air was withdrawn from the crawl space and exhausted
above the roof of the building. In this configuration, the fan flowrate
increased slightly to 279 cfm or about 0.7 ACH. The negative pressures
in the classroom were similar. However, the pressure differential in the
crawl space increased by approximately 73% (from - 0,006 to - 0.01 in.
W.C.) . The radon levels in the classroom were reduced by about 941 (from
10.6 to 0.6 pCi/L) even though the levels in the crawl space increased
by a factor 1.8 (from 29.1 to 53.6 pCi/L). Therefore, while
depressurizing the crawl space lowered the levels in the classroom, it
nearly doubled the levels in the crawl space. This was not unexpected
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since a similar technique applied to a residential house increased the
levels in the crawl space by about a factor of 3 (14,15).
9.1.7.4 Submernbrane Depressurization
The third type of mitigation system implemented was SMD — a type of
ASD applied under a plastic membrane covering the exposed soil. The
total flowrate exhausted from under the plastic liners was 260 cfm when
using ail six suction points shown in Figure 9.1.1. As seen in Figure
9.1.3, the radon levels in the classroom were reduced within a matter of
hours to around background (0.5 pCi/L), and in the crawl space the levels
decreased to 3.5 pCi/L. In an attempt to determine if fewer suction
points could be used, the two suction points in the central sector of the
crawl space were disconnected and the suction pipes to both the fan and
the suction pits were capped. The results are shown in Figure 9.1.4.
The decrease in the crawl space levels is probably not significant, and
the levels in the classroom are the same within the level of uncertainty
of the measurement.
The results from the SMD mitigation technique are consistent with
those found when the same method is applied to residential houses (10,
11, 12), where the area of the exposed soil is typically in the range of
1, 000 to 2, 000 ft2. In this building the area is much larger (4,640 ft2);
however, the resulting reduction in the radon levels using SMD is as good
as that achieved in smaller crawl spaces. The next important research
step is to apply the SMD technique' to crawl space areas on the order
10,000 ft2 or larger.
9.1.8 Results of Initial Mitigation (Winter)
The above measurements were repeated during the winter (December 18,
1990, to January 17, 1991) in order to determine if the results were
consistent with the spring and summer measurements. Analysis of the
winter data (also shown in Figure 9.1.4) supports the results of previous
measurements and the integrity of the SMD system during cold weather.
Detailed analysis of the winter data is described below,
9,1.8.1 Baseline Measurements
No attempt was made to reproduce the open vent (natural ventilation)
condition as this was felt to be an inappropriate operating mode for
wintertime conditions due to freezing pipes. The results for the closed
vent mode in winter were much the same as those obtained in the
spring/summer, with the possible exception that the winter radon levels
in the crawl space were slightly lower than the previous values (63.4
pCi/L compared to 87.2 pCi/L). The lower readings could be due in part
to the fact that the winter measurements were carried out after the soil
was covered with the polyethylene liners. The presence of the plastic
liners covering the soil could act as a partial barrier to soil gas
exhalation. The lower readings could also be due to the fact that the
winter measurement period was much shorter than the spring/summer
measurement period.
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9.1.8.2
Crawl Space
Pressurization
The wintertime crawl space pressurization levels were much the same
as obtained previously. These results indicate that, with the amount of
unconditioned air used, the radon reductions achieved with this
mitigation technique are still less than desirable.
9.1.8.3 Crawl Space Depressurization
Using this technique during cold weather conditions gave very similar
results to those obtained in the spring/summer tests. The wintertime
levels in both the classroom and the crawl space were somewhat higher and
could be due to an increased stack effect normally expected during cold
weather. In order for this technique to be successfully applied year-
round, it is obvious that the installation and testing must be done
during extreme temperature conditions in order to ensure that an adequate
amount of air is exhausted from the crawl space.
9.1.8.4 Submembrane Depressurization
The wintertime radon levels measured with the SMD system operative
were almost identical to the levels measured previously. The average
level in the classroom was within the uncertainty of the measurement
techniques, and the levels in the crawl space were slightly lower than
before. These results clearly indicate that the SMD technique is not
only effective but stable in its ability to lower the radon levels in
both the classroom and the crawl space under varying weather conditions.
9.1.9 Final Radon Levels
As shown in Figure 9.1.4 and discussed above, radon levels for the
rooms located above the crawlspace are well below 4 pCi/L in the
wintertime with the SMD system operating.
9.1.10 Estimated Costs
Cost for the polyethylene liner was $430 and the PVC piping supplies
were approximately $500. The single fan was $170. Total material costs
for the SMD
system was roughly $1,100. Nc estimate is available for the person hour
costs, however installation and testing required about 80 person hours
{2 men X 5 days).
9.1.11 Summary
The results of this project indicate that the SMD technique is the
most effective in reducing elevated levels in both the crawl space and
the classrooms. In this application, the crawl space was large but
fairly simple in geometry. Access to the exposed soil areas was
excellent and, with the exception of the two internal support walls, did
not contain a large number of obstructions such as support piers or
utility pipes lying on the soil. The topology of the soil surface in
this crawl space was relatively smooth. Other crawl spaces may have some
or all of the complications that were absent in this application (17,18) .
Application of the SMD technique in these more difficult crawl spaces
needs further investigation.
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Depressurization of the crawl space is effective in reducing levels
in the classrooms; however, the levels in the crawl space will be
increased. This could pose a problem in buildings that have openings
from the crawl space into the occupied rooms above (e.g., HVAC ducts in
the crawl space, wooden floors over the crawl space, or doors or other
entry openings from the crawl space into the rooms above) or if the crawl
space is occupied on a regular basis. In this building the overhead floor
was a poured concrete slab with very few openings to the classrooms
above. This fact helped to contribute to the effectiveness of crawl
space depressurization.
Pressurization of the crawl space was found to be less effective in
reducing the radon levels than natural ventilation. This method may be
more effective if larger quantities of air are supplied to the crawl
space; however, this may result in increased energy losses and perhaps
could increase the risk of damage to utility lines in cold weather.
Natural ventilation of the crawl space also appears to be ineffective
in reducing the radon levels to acceptable levels. Increasing the
ventilation through larger or more numerous vents may increase radon
reduction; however, the effectiveness of this method depends to a large
extent on the wind patterns outdoors. Also, this method can easily be
defeated by closing vent openings during the colder periods.
The number of school buildings constructed over crawl spaces is not
quantified at the present, although EPA research in over 40 schools has
shown that only 7 of the buildings contain crawl spaces (in combination
with slab-on-grade substructures) . There is little information available
regarding crawl space characteristics, such as floor construction, number
of vents, number of piers and support walls, and the presence of HVAC
ductwork or asbestos in the crawl space. While the SMD technique appears
to be the method of choice for reducing levels in both the crawl space
and the rooms above, further investigations need to be carried out in
crawl spaces that are not as simple as the one used in this study to
determine if it can indeed be applied successfully in non-ideal
conditions.
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SECTION 10
WASHINGTON STATE SCHOOLS
Initial radon screening measurements were made in the Spokane Schools
during 1989, and four of the schools were selected as possible candidates
for additional study. Two Spokane schools identified as having the
highest radon levels investigated in August 1990. The diagnostic
measurements and the recommended mitigation approaches for these two
schools, Lidgerwood and Sheridan, are discussed separately below,
10.1 LIDGERWOOD ELEMENTARY SCHOOL
10.1.1 Building Description
This school is located in the northern part of Spokane. The school
has 16 classrooms, a multipurpose room (gym/cafeteria), and several
special purpose rooms and offices. Eight of the classrooms are built
over a crawl space, and the remaining eight are slab-on-grade. A partial
floor plan of the school is shown in Figure 10.1.1.
10.1.2 Pre-Mitigation Radon Measurements
Several radon measurements were made over all four seasons (spring,
summer, fall, and winter) under a number of ventilation conditions using
two-day CCs, short and long term E-perms, and ATDs as part of an EFA/ORP
study.
These measurements indicate that the eight rooms built over the crawl
space do not have elevated radon levels. As a result, the diagnostic
measurements discussed in this report include only the eight slab-on-
grade classrooms that have consistently measured above 4 pCi/L,
10.1.3 Building Investigation
During August 21-23, 1990 various radon diagnostic tests were
conducted, focussing on the eight slab-on-grade classrooms shown in
Figure 10.1.1. These classrooms are located in the northwest wing of the
school and occupy approximately 8,400 ft2. The design drawings indicated
the presence of aggregate under the slab. Since Lidgerwood contains
several classrooms additions, the foundation drawings available were not
particularly clear on specific subslab foundation locations. The subslab
foundations include both poured concrete footings and thickened slab
footings. Their exact locations can only be inferred from the PFE
measurements discussed in Section 10.1,5.
There is a utility tunnel in each wing located as shown in Figure
10.1.1 under the slabs along the perimeters of the classrooms. This
tunnel is approximately 4 ft wide by 4 ft high with a dirt floor. The
walls of the tunnel are poured concrete and have numerous penetrations,
leading to open soil. Access to the tunnels are in rooms 140 and 141 in
the west section and in rooms 127 and 128 in the eastern section. The
tunnel contains the steam pipes that connect the boiler with the UVs in
each of the rooms. Room 130, located just south of room 128 was also
inspected for radon entry routes since it also had consistently elevated
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radon levels. There were numerous utility penetrations in the slab that
probably constitute the major radon entry routes in this room.
10.1.4 HVAC System and Pressure Differentials
10.1.4.1 HVAC System Design and Operation
The HVAC system for this facility consists of heating-only, three-
speed UVs located in each room, as shown in Figure 10.1.1. Each room has
an electronic thermostat that controls the OA damper and the hot water
valve in the UV. Each unit has a low-limit stat that modulates a hot
water valve to maintain a minimum supply air temperature (typically 60°
F) . The units appeared to be in excellent working order in the subject
rooms (139-142), however from the measurements of OA it would appear that
the damper on the UV in room 142 is not opening fully. Rooms 141 and 142
each have a wind-turbine exhaust ducted into their storage/coat closets.
The turbine for room 142 was inoperable (not turning) during the
investigation. A passive exhaust is located in room 140 and there is no
exhaust in room 13 9 (library).
One section of the school (room 124 specifically) has older UVs that
have been retrofitted with replacement actuators that lack the proper
stroke to open the outdoor air damper. However, this area was not of
concern in the investigation since room radon levels in this section of
the building were relatively low, regardless of the unit ventilator
operation, during all seasonal measurements performed by ORP.
There is no automatic shutoff of the UVs, nor is there an automatic
temperature setback control. It appears that each unit fan runs
continuously, and the unit cabinets and thermostats are inaccessible
without a hex key, thus the fan speeds and temperature settings cannot
be adjusted by the teachers. The unit fans can be shut off at the
electrical panelboard.
10.1.4.2 Potential Radon Impact
The hot water piping is routed to each UV through tunnels under the
perimeter of the slab, as seen in Figure 10.1.1. The return air plenum
for the UV is not isolated from the slab over the tunnel; thus any
opening in the slab (e.g., a pipe sleeve, crack) would allow air from the
tunnel to enter the UV and mix with the room return and OA. The tunnel
could be a contributor to elevated radon levels in the room. Some
openings were found around pipe penetrations but radon sniffs in the
tunnel in room 141 did not exceed 100 pCi/1.
10.1.4.3 Measurements
Air flow quantities were measured for each UV and static pressure
readings were taken in each of the four rooms (139-142). The readings
were taken for the various operating modes of the UVs: 1) UV off; 2} UV
on low, medium, high fan speed; 3) UV with OA damper open and closed.
In addition to these UV modes of operation, the measurements of room
static pressure (relative to outdoors) were taken with the door to the
hallway opened and closed. The results of the pressure measurements are
shown in Table 10.1.1 through Table 10.1.4 and in Figures 10.1.2 through
10.1.5. From past research it has been shown that pressurization of a
space can reduce radon entry. It can be determined from these
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measurements that the optimal operating mode for the reduction of soil
gas infiltration would require the UV to be on (any speed) with the OA
damper in the open position, and the door to the hallway closed. No
other operating mode, or door position would allow for pressurization of
the room. Only the library (room 139 shown in Figure 10.1.2) could be
pressurized with the hallway door closed and the OA damper in the closed
(roughly 10% open) position, likely due the lack of any exhaust system
in the room.
With the UV on, the OA damper open, and the hallway door closed,
relative pressures (room vs. outdoors) in those rooms with wind turbine
and passive exhaust (rooms 140-142) ranged from 0.020 in.W.C. to 0,036
in. W.C. These pressures should be adequate to prevent soil gas
infiltration into the rooms, but require each door to the hallway to be
closed. ' It should be noted that the differential pressure measurements
made with the classroom doors open could be different (perhaps positive)
if measurements were repeated with all UVs in the school turned on. Due
to teacher and staff activity, these conditions were not possible during
the building investigation.
10.1.4.4 HVAC Influence on Mitigation
From the results of this investigation, the unit ventilators could
be used as a mitigation technique and would help to insure ASHRAE
guideline (4) adherence for fresh air delivery to the classrooms (15 cfm
minimum). The initial cost for this technique is relatively low (only
requiring calibration of the UV control systems), however school
operations officials should consider the overall cost which would include
electrical and fuel costs for 24 hour operation and possibly increased
maintenance costs. Officials should also consider the practicability of
requiring all classroom doors to remain closed at all times. Should an
ASD approach be chosen, the system should be sized large enough to
overcome the negative pressures that could occur in the rooms (-0.008
in. ) .
10.1.5 Diagnostic Measurements
In addition to the HVAC systems measurements above, the subslab radon
levels were measured using a Pylon AB5 in the sniffer mode. Radon
measurements were also made in cracks and in openings around utility
penetrations and in the utility tunnels. The locations of the test holes
drilled in the slabs are shown in Figure 10.1.6 along with the subslab
radon levels measured at these points. Also shown in Figure 10.1.6 are
the radon levels measured in the utility tunnels. The first values (ones
with a single asterisk) were measured on 8/22/90 with the results
indicating that the west tunnel (under rooms 139-142) had lower levels
than the east tunnel (under rooms 126-129), 25 pCi/L compared to 180
pCi/L respectively. Each tunnel has four vents (approximately 4 in. by
6 in.) that open to the outdoors. However, the vents for the east tunnel
had been cemented closed probably because of a water problem since the
vents for the east tunnel were at or below grade level. The vents for
the west tunnel were open and fairly clear of debris so that air could
move in and out of this tunnel. The vents to the west tunnel were closed
off using duct tape and left overnight. On 8/23/90 the radon levels in
both tunnels were again measured. The east tunnel (where the vents were
permanently closed) increased slightly from 180 pCi/L the day before to
200 pCi/L. However, the levels in the west tunnel had increased from 25
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pCi/L the day before (with the vents open) to 80 pCi/L (with the vents
closed) as seen in Figure 10.1.6. It would appear that ventilation helps
to dilute the radon levels in the west utility tunnel.
Other radon sniffer measurements were made at several locations.
Measurements in a slab hole under the unit ventilator in Room 139
measured only about 10 pCi/L; however, a hole around a utility pipe
entrance in Room 141 measured about 100 pCi/L. Thus there are probably
ample radon entry routes into the classrooms. Some of these could
possibly be easily sealed, while others may be difficult to locate.
Subslab PFE measurements were conducted in rooms 139, 140, and 141
using the test holes shown .in Figure 10.1.6. The suction point was
located in room 141 and suction was provided by an industrial shop vacuum
cleaner. The results of these differential pressure and flow
measurements are summarized in Table 10.1.5.
In the data shown in Table 10.1.5 note that Fa is the suction point
located in the southwest corner of room 141, Fb is a test hole located
12 in. from the suction point, Fc is a test hole in the center of room
141 and approximately 20 ft. from Fa, Fd is a test hole in the center of
room 140 approximately 32 ft from Fa, and Fe is a test point in the
library office (room 139), approximately 35 ft from Fa. These points are
shown in Figure 10.1.6. Also notice that with no suction at Fa, the
subslab pressure relative to the room was: -0.003 in. W.C. at Fc and
+ 0.005 in. W.C. at both Fd and Fe. The values measured at the test
points with vacuum cleaner suction have been corrected for these baseline
values before arriving at the net pressure differences presented in Table
10.1.5.
The subslab PFEs are summarized in Figure 10.1.7 where the net
pressure differences have been plotted as a function of the distance from
the center of the suction hole. The pressure at the suction point has
been assumed to be at a distance of 0,06 ft from the center of the
suction point (i.e. at the edge of the 1.5 in. diameter suction hole in
the slab) so that the pressure values could be plotted on a log-log
basis. As shown in Figure 10.1.7 the PFE is excellent out to a distance
of 20 ft from Fa but drops off sharply at the test points in the other
rooms. This is probably due to subslab footings that likely surround
each of the classrooms. The footings are poured concrete and serve as
barriers to subslab communication.
10.1,6 Mitigation Strategy
Reducing radon levels by using the UVs to pressurize the classrooms
was discussed in Section 10.1.4 above. An alternate mitigation scheme
for this school would be to use an ASD system. Based upon the subslab
PFE, the pressure field produced under the slab could possibly be
extended up to 40 ft or more if the field was not blocked by the subslab
footings.
One ASD approach is shown in Figures 10.1.8 and 10,1.9. Two subslab
suction points should be installed in each of the two classroom wings,
one each in rooms 139 and 140 and one each in rooms 128 and 129. The
holes through the slab should be at least 4.5 in. in diameter and located
close to the wall. After the holes are cored in the slabs and the
suction pits are excavated under the slabs (at least 1 ft deep and 2 ft
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in diameter), a hole of about 4 in. diameter should be broken through the
foundation walls to the subslab regions under the adjacent rooms, as
illustrated in Figure 10.1,9. This should allow the pressure field to
extend to the subslab regions of the adjacent classroom. These suction
points could be moved slightly from the locations shown in Figure 10.1.8
as long as the points are located along the internal wall to facilitate
breaking through the foundation wall.
For both systems, the slab penetrations from rooms 139 and 140 and
rooms 128 and 12 9 should be manifolded together overhead and connected
with fans mounted on the roof with 4 in. diameter schedule 40 PVC piping
Each fan should have a flow capacity of 230 cfm at 1 in. W.C. The
exhaust from the fans should be directed vertically to achieve maximum
mixing with ambient air. A rain shield should be attached at the top of
the exhaust to minimize water collection in the fan. The fans should be
wired to separate circuit breakers and operated continuously. A low
pressure indicator alarm should also be installed on each mitigation
system to give a visual and/or audio alarm if the breaker is opened or
the fan suction decreases below a given level.
10.1.6,1 Additional Phases of Diagnostics
As discussed above, the two mitigation options for the school are ASD
and pressurization using the UVs. Based on the measurements made during
the diagnostic visit, it is anticipated that installation of ASD systems
in those areas with elevated radon levels will be the most effective
approach for long-term radon control.
However, to determine the ability of the UVs to reduce radon levels
during normal occupancy conditions, a datalogger was installed in this
school from November 29, 1990 to January 8, 1991. Continuous radon
levels were measured in rooms 139, 140, 141, and in the tunnel {a
continuous radon monitor was also located in room 142, however the data
were inadvertently lost when someone unplugged the battery charger).
Differential pressures, temperatures, wind speeds, and directions, and
classroom door openings and closings were also monitored.
The results of these measurements are shown in Figures 10.1.10
through 10.1.39 where the various measured parameters are plotted for
each week (or portion of a week) from November 30, 1990 through January
7, 1991. Each of the 6 groups of figures contain 5 plots each; data for
room 139, data for Room 140, data for room 141, average temperatures in
each room along with the outdoor temperature, and the mean and maximum
wind speeds measured outside the building.
A key factor in the ability of the UVs to lower the radon levels in
the classrooms is the amount of time that the classroom door is open or
closed. The averaged values of: Percent Time Door Open, Percent Time UV
On, and the room Radon Level, are shown in Table 10.1.6 for rooms 139,
140, and 141 where the averaging periods are daytime (8 hours) when class
is (or should be) in session, and the 24 hour period from mid-night to
midnight.
The data for the period 11/30/90 to 12/3/90 (shown in Figures 10.1.10
through 10.1.14) illustrate typical weekend conditions (data for Friday,
Saturday, and Sunday) when the UVs are turned off at about 4:00 pm in the
evening and the doors to the classrooms are closed (the UVs are generally
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turned on at about 8:00 am and off at 4:00 pm on school days and off over
the weekend, however there is no time clock controlling their operation,
the exact on and off times are controlled by the janitors) . With the UVs
off and the doors closed {over the weekend), the air pressures in the
classrooms averaged about - 0.02 in. W.C. relative to the utility tunnel
thus providing a good driving force for radon entry from the tunnel into
the classrooms. During this same period, the pressure differences
between that inside the classrooms and outdoors were rather small and
influenced more by wind effects than any other building parameter.
During this time the outdoor temperatures averaged approximately 30°F
and the room temperatures were about 70°F. The mean wind speeds were on
the order of 5 mph with wind gusts of around 15 mph as shown in Figure
10.1.14. As might be expected, when the UVs are turned off and the rooms
closed, the radon levels begin to increase reaching a maximum on 12/1/90
and then appear to follow a typical diurnal variation with time. The
averaged values for these three days are shown in Table 10.1.6 where the
daytime (8 hour) values increase from less than 1 pCi/L on Friday to a
maximum of just under 20 pCi/L on Saturday and then back to around 5
pCi/L on Sunday.
Data for the week 12/3/90 through 12/9/90 are shown in Figures
10.1.15 through 10.1.19. Operation of the school classrooms during this
period reflect a typical school week and the measured parameters
constitute baseline conditions. During this "normal operation" period
the UVs are on for a period of approximately 8 hours during the daytime
and off at night and over the weekend. The classroom door positions are
controlled by teacher preference with the exception of room 139. This
room houses the library, and it is closed for a slightly larger
percentage of the day than the regular classrooms. The percent of time
that the doors remained open during the daytime was 64.6% for the library
(room 139), 59.7% for room 140, and 52.4% for room 141 as shown in Table
10.1.6. Unfortunately, the radon level data for room 140 during this
period were lost. The average radon levels in the other two rooms were
2.6 pCi/L in room 139, and 1.7 pCi/L in room 141. The large increase in
radon levels seen in both rooms 139 and 141 beginning approximately at
midnight on 12/4/90 is likely the result of wind induced building
depressurization. As seen in Figure 10.1.19 the wind speeds averaged 5
to 10 mph with gusts from 15 to 30 mph. These higher wind conditions
began at a time when the UVs were off and resulted in increased radon
entry from the tunnel and subslab areas. Once the UVs were turned on,
the increased air flow into the classrooms reduced the radon entry and
began to lower the room levels as seen in Figures 10.1.15 and 10.1.17.
For the week of 12/10/90 through 12/14/90 (shown in Figures 10.1.20
through 10.1.24) the teachers in this wing of the school were asked to
keep the classroom doors closed as much as possible. In Table 10.1.6 it
is seen that this request was carried out quite well. The percent of
time that the doors remained open during the daytime was reduced to 7.5
%, 21.9%, and 32% for rooms 139, 140, and 141 respectively. Also, the
unit ventilators were operated near continuously during this week as
opposed to the normal schedule of turning them off at night. The radon
levels remained quite low throughout the week (with the exception of the
levels measured in the early hours of monday morning 12/10/90 in rooms
139 and 141 before the UVs were turned on) . The average radon levels for
this week were less than 0.8 pCi/L during the daytime and less than 2.2
pCi/L for the complete set of 24 hours of measurement. On Saturday and
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Sunday (12/15-16/90) after the UVs were turned off, the radon levels in
rooms 140 and 141 increased in a manner similar to the previous weekend.
The 8 hour and 24 hour averages are shown in Table 10.1.6. During this
same period (Saturday and Sunday), the radon levels in the library (room
139) remained low, averaging less than 1 pCi/L for either the 8 hour or
the 24 hour periods. The reason for this is likely due to the lack of
an exhaust vent in this room and perhaps also due to the higher in-
leakage through the closed OA damper. Data for the remaining weeks of
the test period (12/24/90 through 1/6/91) are shown in the remaining
Figures 10.1.25 through 10.1.39.
Rather than carry out a day-by-day or even a week-by-week analysis
of the data, we chose to look at weekly averages of the 8 hour (daytime)
and 24 hour data. We excluded the weekend data since typically the UVs
were turned off over the weekend. These averages are tabulated in Table
10.1,7. From this table all weekly averaged data for which values were
available for radon, percent time the classroom doors were open, and the
percent time the UVs were on were sorted by increasing radon levels for
both the 8 hour and 24 hour periods. These results are shown in Figures
10.1.40 and 10.1.41. Here it can be seen the overall trends or effects
of door openings and UV operation upon the room radon levels. In
particular, in Figure 10.1.40 it is clear that as the amount of time the
doors were open increases so also does the radon levels. In like manner
but less clearly, as the percent of time that the UVs were running
decreases the radon levels increases. The correlation between the UV on
time and the radon levels is less clear in Figure 10.1.41 because over
the 24 hour period, the UVs are turned off for a much larger percentage
of the time (overnight) than that during normal occupation.
These data indicate that if the classroom to hall doors are kept
closed and the UVs left running, radon levels in the classrooms can be
reduced. The slightly lower levels in room 139 (the library) are
probably due to a combination of factors including; a lower source
strength, no exhaust vent (passive or turbine), and the library door is
probably closed more frequently than the classroom doors.
10.1.7 Estimated Cost
The costs of the materials for each of the two ASD system would be
about $2,000 for piping, fittings, fans, and caulking. The labor costs
could be quite low if the work is performed in-house by the school
maintenance staff, otherwise labor costs from a private firm could run
in the neighborhood of $4,000 for 5 days of work for two persons. The
total maximum cost should be around $6,000 or less for each of the two
systems.
10.1.8 Summary and Recommendations
This school building has both slab-on-grade and utility tunnel
construction details. It also has UVs that, with some effort could
possibly be made to pressurize the rooms for radon control. However,
because the UVs are not controlled by any type of energy management
system or even by a time clock, radon control could be a hit-or-miss
situation. There are too many operational uncertainties to recommend
using the unit ventilators as a reliable mitigation option.
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Another interesting aspect of the school was the absence of elevated
radon levels in those classrooms located over the crawl space areas.
With the amount of exposed soil under the rooms and the fact that the
floors were of wood construction would lead one to expect just the
inverse of what the measurements indicate. No answer is immediately
obvious.
10.2 SHERIDAN ELEMENTARY SCHOOL
10.2.1 Building Description
This school is located in the southeastern corner of Spokane. The
building has two floors with some of the rooms on the first floor located
below grade by about 5 ft. The total number of classrooms in the school
is approximately 35 with additional space for a gymnasium, cafeteria,
kitchen, counseling and general offices, and storage rooms. The building
has a central HVAC system with the air handling equipment located on the
second floor. The Spokane School district has several schools that have
the same floor plan as Sheridan.
10.2.2 Pre-Mitigation Radon Measurements
Several radon measurements were made over all four seasons (spring,
summer, fall, and winter) under a number of ventilation conditions using
two-day CCs, short and long term E-perms, and ATDs. The results of these
measurements indicate that several rooms on the first floor of the school
do indeed have elevated radon levels when the HVAC System is not
operating. However, during the HVAC system operation, the radon levels
are well below 4 pCi/L. This suggests that the HVAC system is
pressurizing the building and thereby preventing radon entry. More
detailed information is discussed below in Section 10.2.4.
10.2.3 Building Investigation
On August 22, 1990 the school was visited for a short diagnostic
examination. Investigations centered around the HVAC system and its
ability to pressurize the building. Tests of the HVAC operation were
carried out primarily on the first floor in rooms 129 and 133. The
results of these tests are described below in Section 10.2.4. The
building is of modern construction (less than 10 years) and the design
drawings indicate the presence of aggregate under the slabs. The floors
of most rooms in the school are carpeted.
10.2.4 HVAC System and Pressure Differentials
10.2.4.1 HVAC System Design and Operation
The HVAC system for this facility consisted of a central forced-air
system with variable air volume (VAV)/hot water reheat temperature
control. There are three AHUs located in a mechanical room on the second
floor, one unit serves the gym/multi-purpose room, one serves other
interior rooms, and one large unit serves all exterior rooms (classrooms
and administrative offices). Since all classrooms and administrative
areas are served by the large unit, only the large AHU will be discussed.
66
-------
The AHU contains a cooling coil and OA return/relief damper system
(capable of 100% outdoor air). The unit supplies conditioned air to all
external rooms on two floors of the building. The return air system is
not ducted from each room, rather grilles in the dropped ceiling of each
room transfer the return air to the ceiling plenum, A return/exhaust fan
in the mechanical room draws air through another grille located above the
second floor ceiling, drawing the return air through the plenum space
above the dropped ceiling and through a few open chases to the first
floor plenum ceiling.
Each room has a pneumatic thermostat that controls a VAV box by
modulating the control damper, and by modulating a hot water control
valve in the box. On a call for cooling, the hot water valve modulates
to a closed position and the control damper modulates to maintain the
desired conditions. On a call for heating, the VAV boxes modulate to a
minimum supply air position and the hot water valve modulates to maintain
desired room conditions. According to building construction documents,
the VAV boxes have a minimum supply air position that is 50% of the
maximum supply.
The AHU operates from 7:00 a.m. until 4:30 p.m., and is shut off
completely during summer vacation. The controls system was in the
process of being changed over to the central plant's energy management
system during the investigation, but there was no plan for a change in
the operating hours.
10.2.4.z Potential Radon Impact
This HVAC system operates in such a manner so as to pressurize the
building, this pressurization should prevent soil gas infiltration as the
ORP radon test data shows, (the lowest levels tend to occur when the AHU
is running). As long as the HVAC system is operating, the radon levels
in the school should be low.
Caution should be exercised with this radon control approach since
the return air system has no means for balancing (no dampers) . The lack
of a ducted return system contributes to less-than-ideal air distribution
in this building and could result in varied relative static pressures
throughout the building. Those areas nearest the return fan louver may
experience negative static pressures (relative to outdoors) due to excess
return air and could experience increased soil gas entry. Other areas
of the building farther from the return air louver could experience
s-lightly higher static pressures relative to outdoors due to lack of
sufficient return air.
1C.2.4.3 Measurements
Air flow quantities were measured in room 133 and were found to be
in the range of air flow called for on the prints {523 - 1045 cfm) .
Smoke pencil tests near the windows and floor/wall cracks indicated the
room to be at a positive pressure.
67
-------
10.2.4.4 HVAC Influence on Mitigation
Pressurizatior. via the HVAC system is the most likely mitigation
choice for this facility since the system is designed to pressurize the
facility continuously and has demonstrated the ability to reduce radon
levels below 2 pCi/1. Further data acquisition is recommended, however,
to determine the effect of night and weekend shut-off of the ABU.
Continuous data of radon levels in room 133 should be taken with various
operating schedules of the HVAC system. From this, the radon build-up
rate and the radon mitigation rate can be determined so that the optimal
HVAC system start-stop time may be determined.
10.2.5 Diagnostic Measurements
No other diagnostic measurements other than those described above in
Section 10.2.4 were carried out at this school.
10.2.6 Mitigation Strategy
The recommended mitigation strategy for this school is to use the
HVAC system to maintain building pressures above ambient levels. The
determination of optimum set-back time for the system can best be
determined through the use of continuous radon monitors and perhaps by
continuous measurements of the pressure differences between the building
interior and outdoors in several of the classrooms, each located a
different distance from the central air-handler.
10.2.7 Summary and Recommendations
It is recommended that continuous radon and possibly pressure
transmitters be installed at various locations in the building during the
winter to monitor the building for at least one week. This could be done
using the school districts monitoring equipment during the winter months.
68
-------
SECTION 11
QUALITY CONTROL AND QUALITY ASSURANCE
11.1 INTRODUCTION
This section covers quality control EQC) and quality assurance
(QA) for the research conducted in the 13 schools discussed in this
report. QA/QC requirements apply to this project. The data are
supported by QA/QC documentation as required by U.S. Environmental
Protection Agency policy. The schools are located in Colorado (2
schools), Maine (2 school), Minnesota (1 school), Ohio (4 schools),
South Dakota (1 school), Tennessee El school), and Washington (2
schools). Investigations in these schools centered on the use of ASD
(4 schools), SMD {I school), central HVAC systems !3 schools), and UV
(4 schools) systems as used for radon mitigation.
11.2 QUALITY ASSURANCE PROJECT PLAN
A Quality Assurance Project Plan (QAPP) was submitted April 30,
1991 and revised and approved June 24, 1992 for the work performed by
SRI. The Data Quality Objectives as described in that QAPP were met
during the course of this research project.
11.3 CHARCOAL CANISTER MEASUREMENTS
In the course of these school investigations, radon screening
measurements were carried out by local officials of the school board
or their representatives using charcoal canisters provided by EPA,
The CCs were provided by and analyzed by EPA's National Air Radiation
Laboratory (NAREL) in Montgomery, Alabama.
11.3.1 Assessment of Precision
Ten percent of the CCs provided by NAREL were deployed as
duplicate measurements. The collocated detector results are listed in
Table 11.3.1 along with: the average value of each collocated pair,
the standard deviation expressed in pCi/L, and the coefficient of
variation (CV) expressed as a percentage for each set of measurements.
The average of the standard deviations for all of the measurements was
0.2 pCi/L with the highest and lowest values of 2.3 and 0.0 pCi/L
respectively. The average of the CV values for all of the
measurements was 3.9 % with a maximum and minimum of 23.1 % and 0.0 %
respectively. The average value of 3.9 % for the overall CV was well
within the data quality objective of 10 %.
11.3.2 Assessment of Accuracy
No spiked measurements were carried out to assess the accuracy of
the CC measurements. The CC measurements in these projects relied
instead upon the QA/QC checks carried out by NAREL itself.
69
-------
11.3.3 Assessment of Completeness
With the exception of less than 10 CCs deployed, valid results
were obtained. This is well within a completeness criteria of 90 %.
11.4 CONTINUOUS RADON MONITORS
11.4,2 Assessment of Accuracy
The continuous radon monitors (CRMs) used in this study were
calibrated by the manufacturer as shown in Table 11.4.1. Background
checks of the instruments were carried out both before and after each
field use. The average background counts were subtracted from the
gross field counts before the actual radon levels were cslculated.
11.5 DIFFERENTIAL PRESSURE MEASUREMENTS
Before deploying the cells in the field and once upon their return
to the laboratory, the calibration span was checked using a Dwyer No.
1420 Hook Gage. This instrument is capable of calibration over a
range of 0 to 2 in.W.C. to an accuracy of 0.001 in.W.C. The Dwyer No.
1420 complies with Federal specifications GGG-C-105A and is traceable
to a master at the National Institute of Science and Technology
(formerly the National Bureau of Standards).
11.6 CONTINUOUS MONITORING PROCEDURES
Continuous monitoring of parameters other than radon were used
where it was determined to be helpful. The primary mechanism for
continuous data acquisition of time-dependent parameters was a
programmable electronic datalogger incorporated in the monitoring
instrumentation package for each study school building. Analog
signals, such as from temperature and relative humidity probes, were
sampled once every 0.1 min. Thirty minute averages of 300 one-tenth-
minute readings were stored in datalogger memory as a single record.
Pulsed outputs from the Continuous Radon Monitors was integrated for
the entire 30 minute interval. Logic signals, such as from sail
switches for HVAC operation or classroom door opening switches, were
interrogated every 0,1 min. The duty cycle for switch-on operation
was recorded as a fraction (i.e., 0.5 for 50%) for every 30-minute
interval.
Indoor and outdoor temperatures were monitored on a near-
continuous basis using either/or Type K thermocouples and calibrated
thermistors. Differential pressure transducers (Modus, Inc., Model
T20) were used to monitor differential pressures from an indoor
reference point to locations outside, under the slab, and possibly at
other points within the school building. Radon signals from the
continuous radon monitors were counted using the datalogger as well as
the Pylon A3-5 counting circuitry.
70
-------
11.7 NON-CONTINUOUS MEASUREMENT PROCEDURES
Other measurements included air infiltration tests (blower door or
tracer gas) , sub-slab communication tests (pressure field extension),
sub-slab radon profile mapping, C02 concentration measurements, HVAC
flow rate measurements, and spot pressure differential measurements.
These measurements were made following current AEERL protocol.
11.8 AUDITS
No EPA Field or Internal Audits were conducted during the period
covered by this report.
71
-------
SECTION 12
REFERENCES
1. Leovic, K.W., Craig, A.B., and Harris, D.B. "Update, on Radon
Mitigation Research in Schools." Presented at the 1991 Annual
American Association of Radon Scientists and Technologists
National Fall Conference, Rockville, MD. October 9-12, 1991.
2. Leovic, K. W. "Summary of EPA's Radon Reduction Research In
Schools During 1989-90." EPA-600/8-90-072 (NTIS PB91-102038),
U.S. Environmental Protection Agency, Air and Energy Engineering
Research Laboratory, Research Triangle Park, NC, October 1990.
3. Harris, D.B. and Pyle, B.E. "Data Logging Systems for Monitoring
Long-Term Radon Mitigation Experimental Programs in Schools and
Other Large Buildings." Presented at the 85th Annual AWMA
Meeting, Kansas City, MO, June 21-26, 1992.
4. ASHRAE Standard 62-1589. "Ventilation or Acceptable Indoor Air
Quality," ASHRAE, Atlanta, GA, 1989.
5. U.S.EPA (ORP). "Radon Measurements in Schools - An Interim Report,"
EPA-520/1-89-010 {NTIS PBS9-189419}f March 1989.
6. Brennan, T., Fisher, G., and Turner, W. "Extended Heating,
Ventilating and Air Conditioning Diagnostics in Schools in
Maine." In Proceedings: The 1991 International Symposium on
Radon and Radon Reduction Technology, Vol.2, EPA-600/9-91-C37b
(NTIS PB92-115369, November 1991.
7. U.S.EPA (ORP). "Radon Reduction Techniques in Schools - Interim
Technical Guidance." EPA-520/1-89-020 (NTIS PB90-160086),
October 1989.
8. Leovic, K.W. and Craig, A.B. "Radon Prevention in the Design and
Construction of Schools and Other Laroe Buildings." EPA/625/R-
92/016, January 1993.
9. Leovic, K.W., Harris, D. B., Dyess, T.M., Pyle, B.E., Borak, T., and
Saum, D.W. "HVAC System Complications and Controls for Radon
Reduction in School Buildings." In Proceedings: The 1991
International Symposium on Radon and Radon Reduction Technology,
Vol.2, EPA-600/9-91-037b (NTIS PB92-115369) , November 1991.
10. Leovic, K.W., Craig, A.B., Harris, D. B., Pyle, B.E., and Webb, K.
"Design and Application of Active Soil Depressurization (ASD)
Systems in School Buildings." In Proceedings: The 1991 International
Symposium on Radon and Radon Reduction Technology, Vol.4, EPA-600/9-
91-037d (NTIS PB92-115385), November 1991.
11. Pyle, B.E., Leovic, K.W., Dyess, T.M., and Harris, D.B. "Comparison
of ASD and HVAC Control In School Buildings." In Proceedings: The
1992 International Symposium on Radon and Radon Reduction
Technology. Vol. 2. EPA-600/R-93/083b (NTIS PB93-196202), May 1993.
72
-------
12. Leovic, K.W., Craig, A.B., Dyess, T.M., and Pyle, B.E.
"Effectiveness of HVAC Systems For Radon Control In Schools." In
Proceedings; The 1992 International Symposium on Radon and Radon
Reduction Technology, Vol. 2, EPA-600/R-93/083b (KTIS PBS3-196202),
May 1993.
13. Pyle, B.E. and Leovic, K.W. "A Comparison of Radon Mitigation
Options for Crawl Space School Buildings." In Proceedings: The 1991
International Symposium on Radon and Radon Reduction Technology,
Vol.2, EPA-600/9-91-03?b (NTIS PB92-115369}, November 1991.
14. Craig, A.B., Leovic, K.W., Harris, D.3.,and Pyle, B.E. "Radon
Diagnostics and Mitigation in Two Public Schools in Nashville,
Tennessee." In Proceedings: The 1990 International Symposium on
Radon and Radon Reduction Technology, Vol.2, EPA-600/9-91-026b
(NTIS PB91-234450), July 1991.
15. Pyle, B.E., Williamson, A.D., Fowler, C.S., Belzer, F.E. Ill,
Osborne, M.C., and Brennan, T. "Radon Mitigation Techniques in
Crawl Space, Basement, and Combination Houses In Nashville,
Tennessee." In Proceedings: The 1998 Symposium on Radon and
Radon Reduction Technology. Vol. 1. EPA-600/9-89/006a (NTIS
PB89-167480), March 1989.
16. Pyle, B.E. and Williamson, A.D. "Radon Mitigation Studies:
Nashville Demonstration," EPA-600/8-90/061(NTIS PB90-257791i,July
1990.
17. Brennan, T,, Pyle, B., Williamson, A., Belzer, F,, and Osborne, M.
"Fan Door Testing on Crawl Space Buildings," Air Change Rate and
Airtightness in Buildings, ASTM STP 1067, M.H.Sherman, Ed., American
Society for Testing and Materials, Philadelphia, PA, 1990, pp. 146-
150.
18. Leovic, K.W., Craig, A.B., and Saum, D.W. "Radon Mitigation
Experience In Difficult-To-Mitigate Schools." In Proceedings:
The 1990 International Symposium on Radon and Radon Reduction
Technology, Vol.2, EPA-600/9-91-026b (NTIS PB91-234450), July
1991.
73
-------
-------
APPENDIX A
FIGURES
A-l
-------
1902
ADDITION
CN
«
T
-------
n
"SI
1-1
* kj-
fflr
¦ -
-------
KINDERGARDEN
I]
(8.8)
T4
RM 1
(5.5)
Figure 4,1.3. Results of January 1990 radon screening measurements at Barton
Elementary School, in pCi/L.
A—4
-------
KINOERGAROEN
0-2)
Figure 4.1.'4. Results of February 1990 radon follow-up measurements at
Barton Elementary School, In pCi/L.
-------
u
c.
m
Gj
>
iy
<
CE
2 3 « 3 S 7 8 8 10 11 1! 13 14 15 IS 17 18 19 JO 21 22 23 24 23 26 27 23 29 30 31
TEST NUMBERS
i "lijan Screening Feb FqHow-ud
Figure 4,1,5, Comparison of the January 1990 arid February 1990 radon
measurements at Barton Elementary School (some of the January
tests were not repeated in February).
A-6
-------
Figure 4,1,6, Floor plan showing the locations of subslab grade beans and
thickened slabs at Barton Elementary School.
A-7
-------
KINOERGAROEN
fa -
(730)
(500 )•
(700)
RU 5
RM 4
MEDIA
< CENTER
h-
Till
¦50'
J
PRi | 0F5r
!
LOUNGE ! S
i >y
r
RM 12
—1
RM 11
N
Figure 4.1.7, Location of subslab test points used during the communication
and radon profile tests at Barton Elementary School, radon
levels in pCi/L.
A-8
-------
01 STANCE FFCM SUCTION POINT Cft3
_
-------
i r
02/25/91 02/26/91 02/27/91 02/28/91 03/01/91 03/02/91
K'garden
DATE
Room 1 RA Tunnel —b— OA Damper
Figure 4.1.9. Effects of opening OA damper upon radon levels at Barton Elementary.
A-l 0
-------
=* Kindergarden + Room 1 x Air Return Tunnel
~ Room 6 (TB) x Room 6 (AB5)
Figure 4,1.10. Correlation of the 8 hour average radon levels with the 8 hour
average OA damper positions at Barton Elementary.
A-11
-------
10 20 30 40 50 60 70 80 90
PERCENT OA DAMPER OPEN
* Kindergardsn ¦+¦ Room 1 * Air Return Tunnel
G Room 6 (TB) x Room 6 (ABS)
100
110
Figure 4.1.11. Correlation of the 24 hour average radon levels with the 24
hour average OA damper positions at Barton Elementary.
A-12
-------
50'
40-
Q
& 30-
—i
LLI
>
LU
O 20-
Q
10-
26
m
m
*•
m.
•5W
m
m
^ M $6
m
To 20 30 4€ 50 50 70 80~
PERCENT OA DAMPER OPEN
90
100
110
Figure 4.1.12. Correlation, of the 8 hour average subslab radon levels with
the average OA damper positions at Barton Elementary.
A—13
-------
50
40-
O
a 30-
_j
iu
>
LU
O
Q
<
cc
20-
10-
*
* s#
*
*¦
0 10 20 30 40 50 60 70 80 90 100 1
PERCENT OA DAMPER OPEN
Figure 4.1.13. Correlation of the 24 hour average subslab radon levels with
the average OA damper positions at Barton Elementary.
A-14
-------
" i r r r r i—r-!—i ir r r ir f i r ir i i ir i i ir i—r ir i f r r
1 2 3 4 5 5 7 8 9 10111213141516171819202122232425262723293031
TEST NUMSERS
Figure 4.4.14 Comparison of all radon measurements made at Barton Elementary
School (some tests were not repeated each time).
A-15
-------
Figure 4.2.1. Floor plan showing building additions and subslab footer
locations at Flatteville Elementary School.
A-16
-------
Figure 4,2.2. Location of canister numbers for CC measurements in
Platteville Elementary School.
A-17
-------
N
A
SCALE:
|* 100' -
Figure 4.2.3. Results of March 1990 radon screening measurements in
Platteville Elementary School, in pCi/L,
A-18
-------
Figure 4.2.4, Results of August 1990 follow-up radon measurements In
Platteville Elementary School, in pCi/L.
A-19
-------
15
J
\
«*
u
Q.
1 3 5 7 9 11 13 15 17 Id 21 23 25 27 29
2 4 6 8 10 12 14 16 IS 20 22 24 26 28
CC TEST ROOM NUMBERS
March 1990 Screening H August 1990 Follow—up
Figure 4.2.5. Comparison of the March 1990 and August 1990 measurements at
Platteville Elementary School, in pCi/L.
A-20
-------
Figure 4,2.6. Locations of suction and test points used in subslab
communication tests and the radon levels under the slab at
Platteville Elementary School, in pCi/L,
A-21
-------
fi
V
u
%
%
H
100
10
0.1
p 0.01 -
5, 0.001
0.01
0.1 1 10
DISTANCE FROM SUCTION POINT (tc)
,SP=-10»
SP=-15»
,SP=-20»
SP=
Figure 4,2.7. Pressure field extensions from suction point 1 located in Room
16 at Platteville Elementary School, the SP values are the
applied suction pressure in inches of water column.
A-22
-------
T* T% 4 *1
xJa Rml3
^N^Fb
\
i
i i
\fc
0.01
0.1 1 10
DfMfn ¦ % t * it"« /% % * mr f ¦¦friTi^ % t n/Ntv/ * \
ISTANCE FROM SUCTION POINT (ftY
100
SP=-27*
SP=-37"
SP=-44«
k/i —*» Tt
Figure 4.2.8.
Pressure field extensions from suction point 2 located In Roon
13 at Platteville Elementary School, the SP values are the
applied suction pressure in inches of water column.
A-23
-------
Figure 4,2,9, Approximate pressure field extensions measured at Flatteville
Elementary School.
A-24
-------
6"PVC
MAIN
ABOVE
CEILING
TILES
FAN (230 CFM at 1"WC)
SYSTEM 3
SYSTEM 4
FAN
(135 CFM at 1"WC)
4"PVC
UNDER
^~| STAGE
4"PVC
SYSTEM 2
FAN (230 CFM at 1"WC)
IN BOILER ROOM
EXHAUST OVER ROOF
2"PVC DROPS
WITH PITS
Figure 4.2.10, Proposed mitigation systems for Placceville Elementary School.
A-25
-------
TO FAN
Figure 4.2,11. Subslab suction point details for 4 inch diameter suction
pipe.
A-26
-------
TO FAN
OR SUPPLY MAIN
Figure 4.2.12. Subslab suction point details for 2 inch diameter suction
pipe.
A-27
-------
15
J
0
Q,
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29
2 4 6 S 10 12 14 16 IS 20 22 24 26 28
CC TEST ROOM NUMBERS
I I Dec. 1990 HVAC On H Dec. 1990 HVAC Off
Figure 4.2.13, Comparison of the December 1990 cc measurements made with the
HVAC units on and off at Platteville Elementary, Platteville
CO.
A-28
-------
A 200
4
9 11 13 15 17 19 21 23 25 27 29
10 12 14 16 IS 20 22 24 26 28
CC TEST ROOM NUMBERS
Figure 4,2,14, Changes in the radon levels when Che HVACs on versus when off
at Platteville Elementary, Platteville, CO.
A-29
-------
15
m
0
o.
1 w
i
1
J
2 5
0 5
fl
o
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29
2 4 6 $ 10 12 14 16 18 20 22 24 26 28
CC TEST ROOM NUMBERS
March 1990 Screening March 1991 Follow—up
Figure 4.2.15. Comparison of the March 1990 and March 1991 measurements at
Placteville Elementary, Flatteville, CO.
A-30
-------
N
1941
Rebuilt
Section
Original
Building
Figure 5.1.1 Floor plan of the basement rooms of the NW wing of
Sanford Middle School, Sanford, ME.
A-31
-------
N
Fg
(40002/-0.305)
(+0,GQV-C.005>
Fh
(+0.006/-3.017)
Fj
(-MX005/-0.01S)
Fe (+O.OC5/-O.OU)
Fd <+o.oov-o.oi9)
SUCTION POINT §2
(-0 OI2/-2.52)
/SUCTION POINT #1
Fm
(0.000/-0.156)
A13 VENT *\
(+0.01 2/-0.G1Q)
BOYS
TOILET
Figure 5,1.2
Location of mitigation system installed and subslab
communication test results in the NW wing of Sanford
Middle School, Sanford, ME (in.W.C.-fan off/in.W.C.-fan on).
A-32
-------
VENT
HOOD
ill "f nr
Xx
¦ ' i ' ~
f1'1; i'i •ir; i-. _.
I t I I I I 111' I
I I I I
ill!
I T"' I I ' I"
Figure 5,1,3. Location of fan mounted on the roof of Sanford Middle School,
Sanford, ME.
A—3 3
-------
10
A
J
\
•Ml
0
tk
V
M
111
1
z
0
o
INSTALL SYSTEM
FAN TURNED ON
09/10/90
09/11/90 09/12/90
DATE{at 10:15 am)
m Rm A14 , Riu A15
09/13/90
Figure 5.1.4. Tentative results of the mitigation system installed in
Sanford Middle School, Sanford, HI.
A-34
-------
1
3
"ST
au
en
HRV A
t
i—i
26
24
82
N
t
20
LIBRARY
rEADCRS
LOUNGE
SUPPLY
6
S
10
12
OFFICE
S
7
9
11
13
Figure 5.2.1 Plan view of Russell Elementary, Gray, ME.
A-35
-------
1040
1030
1020
1010
1000 -
990
980
970
960
950
940
Barometric Pressure
/!
r
Room 25 Room 1 '
x )
i i i r
3/3/92 3/5/93 3/7/92 3/9/92 3/11/92 3/13/92 3/15/92
Date
Figure 5.2.2.
Correlation of radon level increases with changes in
barometric pressure at Russell Elementary School, Gray, ME.
A-36
-------
09/(51/92 15:47 ®919 341 2157
EPA/AEERL/RTP.NC
1)010
25
tin. WC)
Figure 5.2.3. ASD performance, for center wing of Russell Elementary.
A-37
-------
Date
Figure 5.2.4. Conci.nu.ous C02 levels in HRV room at Russell Elementary Gray
ME. 'J<
A-38
-------
o
UNIT VENTILATORS
>
I
OJ
VO
Figure 6.1.1. Floor plan of Nokomls Elementary School, St. Paul, MN, showing
radon mitigation system locations.
O
O
-------
% *
1
B 1
•§ 3
cc
Tan Number
1 - UVa and AMU a! Normal Damper Gge ration; ASD Qn
2-UVa, AHU ASOOff
3-UVs and AHU On, Damper Qoasd
3A-UV8 and AHU On, Dampers Cloaed, Rite** Out
4-UVa and AHU at 10% Damper Open
5-UVaand AHU as 50% Damper Open
G-UVaand AHU oi Normai Oamper Open
7 - UVa and AHU at Normal Damper Operation; ASD On
3- Same aa Test 1 {Two Weeks La tar)
¦a
i
3A
~
Office
Tat Number
I Room 106
Room 10?
Figure 6,1.2.
Radon levels during the resting period at Nokomis Elementary
School.
A-40
-------
5 5
¥4
>
u
i-j 3
c
o
T3 ~
ca 2
06
1
0
Test Number;
9 - UVs,AHU.ASD Off
10 - UVs.AHU Off, ASD On
11 - UVs.AHU.ASD On
10
Test Number
11
CZD Office
Room 107
Figure 6.1.3. Radon levels during additional testing period at
Nokomis Elementary School (no data for Room 106)
A-41
-------
A-42
-------
N
0 ®
2 J—
~ ©
0
s)
©
0
LJ
@
©
©
*2)
6 0
8 CD
10 (D
12 ©
©i
5 ©
7 ©
9 ©
11 ©
©
©
Figure 7.1.2. Location of canister numbers for CC measurements and
foundation walls and footings in Oakaont Elementary School.
A-43
-------
N
FT3
12. 1
II .0 *»
iP
n. 5
6
15. 1
8
!6.@
10
28.5
12
19.3
18.3
5
IS.3
7
11,S
S
18.9
1 1
Figure 7.1.3 Results of E-Perm measurements, Oakmont Elementary School during
the Winter of 1990-91, in pCi/L.
A-44
-------
9
O
N
5.5
<0,5
o
XV/
-------
Figure 7.1.5. Plan view of the tunnel and arrangement of the HVAC system at
Oakniont Elementary School.
-------
Figure 7.1.6. Correlation of OA damper indicator and calculated percent OA
using temperatures at Oakmont Elementary School, Columbus, OH.
A-47
-------
100 %RA 50%RA/50%OA* 100%OA
HVAC Operating Condition
S3 Rm 6 HRm 7 ®Rm8 E]Rm IOlZRui 12Z^T'Lng
Limited data for this condition
Figure 7,1,7, Effects of outdoor air in HVAC system on room radon levels at
Oakxnont Elementary (before tunnel sealing).
A-48
-------
25
s20
U
a,
15
>
c 10
PS
ab
>
< 5
0
100%RA 50%RA/50%OA* 100%OA
HVAC Operating Condition
W W-TunndS E-Tunnel
Limited data for this condition
Figure 7.1.8,
Effects of outdoor air in HVAC system on tunnel radon levels
at Oakmont Elementary (before sealing tunnel).
A—49
-------
25
£20
U
a.
-15
I!
c 10
Q6
m
< 5
0
100%RA 50%RA/50%OA* 100% OA
HVAC Operating Condition
S22 ClassroomsEI2 Tunnel
* - Limited data for this condition
Figure 7,1.9.
Effects of outdoor air in HVAC system on radon levels at
Oakmont Elementary (before tunnel sealing).
A-50
-------
25
0
o,
s20
>
o
J
15
10
60
<1
0
100%RA 50%RA/50%OA 100%OA
HVAC Operating Condition
Rm 6 HRm 7 ®Rm8 3Rm 103Rm 12lZ3T'Lng
Figure 7.1.10. Effects of outdoor air in HVAC system otv room radon levels at
Oakmont Elementary (after tunnel sealing).
A-51
-------
25
^20
o
a.
ris
o
>
> _
< 5
0
100 %RA 50%RA/50%OA 100%OA
HVAC Operating Condition
S3 ClassroomsEi2 Tunnel
Note: Numbers above bars are percent reduction due to sealing tunnel.
Figure 7.1.11. Effects of outdoor air in HVAC systems on tunnel radon levels at
Oakmont Elementary (after tunnel sealing).
h-52
-------
Original Building 1951
1957 Addition
Measurement Locations
Figure 8.1,1. Floor plan of Lincoln Elementary School showing addition
dates, room locations, and CC measurement location.
A-53
-------
Figure 8,1.2. Winter 1990-91 ATD results and the May 1991 CC measurements
made with UV's on/off at Lincoln Elementary, in pCi/L.
A-54
-------
40
^30
ffl
^20
-
o
Q 10
~ Winter(90—91)
Office P'Off
4 Gvm T'Lng B'Room
ROOM NUMBERS
Screening(HVAC (2i§ Screening(HVAC On)
Figure 8,1.3. Comparison of radon levels in Abraham Lincoln Elementary
School (part 1).
A-55
-------
CHI Winter(90—91)
H'Room 17-Lib
14 16 18 20
ROOM NUMBERS
I Screening(HVAC CS5 ScTeening(HVAC On)
Figure 8.1.4. Comparison of radon levels in Abraham Lincoln Elementary
School (pare 2).
A-56
-------
300
§ 200
53
E- 100
0
¦100
Office P'Off 9
4 Gym T'Lng B'Room
ROOM NUMBERS
Figure 8,1.5,
Changes in radon levels with unit ventilator on compared to
levels when off at Lincoln Elementary, (part 1).
A-57
-------
300
200
100
0
•100
11 13 H'Room 17-Lib
12 14 16 18
ROOM NUMBERS
19
20
Figure 8,1,6, Changes in radon levels with unit ventilator on compared to
levels when off at Lincoln Elementary, (part 2),
A-58
-------
A-59
-------
Figure 8.1.8. Locations of the subslab communication test points and the
subslab radon levels measured at Lincoln Elementary, in pCi/L.
A-60
-------
A—61
-------
EFFECTS OF ROOM OPERATING CONDITIONS ON
RADON LEVELS IN ROOM 1. ASD OFF, WEEKDAYS ONLY
EFFECTS OF ROOM OPERATING CONDITIONS ON
RADON LEVELS IN ROOM I, ASD ON. WEEKDAYS ONLY
Figure 8.1.10. Comparison of HVAC and ASD In Room 1, Lincoln Elementary.
-------
EFFECTS OF ROOM OPERATING CONDITIONS ON
RADON LEVELS IN ROOM 4. ASD OFF, WEEKDAYS ONLY
EFFECTS OF ROOM OPERATING CONDITIONS ON
RADON LEVELS IN ROOM 4, ASD ON, WEEKDAYS ONLY
Unit Ventilator/Exh Fan Operation Unit Ventilator/Exh Fan Operation
Figure 8.1.11.
Comparison of HVAC and ASD In Room 4, Lincoln Elementary.
-------
EFFECTS OF ROOM OPERATING CONDITIONS ON
RADON LEVELS IN ROOM 13, ASD OFF, WEEKDAYS ONLY
EFFECTS OF ROOM OPERATING CONDITIONS ON
RADON LEVELS IN ROOM 13, ASD ON, WEEKDAYS ONLY
Unit Vent)lator/Exh Fan Operation
y
y
y
y
y
/
/
24 HOUR AVERAGES
UV-4HX-0 UV-OCX-I UV-1/U-4 UV-I/IX-I
Unit Ventllator/Exh Fan Operation
Figure 8.1.12. Comparison of HVAC and ASD in Room 13, Lincoln Elementary.
-------
EFFECTS OF ROOM OPERATING CONDITIONS ON
RADON LEVELS IN ROOM 16, ASD OFF, WEEKDAYS ONLY
EFFECTS OF ROOM OPERATING CONDITIONS ON
RADON LEVELS IN ROOM 16, ASD ON, WEEKDAYS ONLY
Unit Ventllator/Exh Fan Operation Unit Vantllator/Exh Fan Operation
Figure 8.1.13. Comparison of HVAC and ASD in Room 16, Lincoln Elementary.
-------
N
-TO SOG ROOMS
53=
l^=
VENTS
WEATHER STATION POLE
-VENTS
/
4"PVC
¦24'
¦s
IS'
n-
CN
T
A
a
7
-------
FAN EXHAUST
OVER ROOF
AWAY FROM
ANY INTAKES
ROOF ZlAE ^
c
FAN MOUNTED
AT OR NEAR
ROOF LEVEL
EXIT THROUGH
BLOCK VENT
OR WALL HOLE
*" DIAMETER PVC PIPE
SS-4Q
TO OTHER
SUCTION POINTS
(IF NEEDED)
TREATED PLYWOOD
Figure 9.1.2. Typical sub-membrane depressuxization system for crawl spaces.
A-67
-------
u
3
i—) 60
gi
a
z 40
o
Q
2
SMD (6 Pu)
SMD Off
OS Pro.
SMDOd-
<«Pu)
I2/IIV90 12/20/90 12/22/90 12/24/90 12/26/90 12/28/90 12/30/90 01/01/91 01/01/91 01/05/91 01/07/91 01/09/91 01/11/91 01/11/91 0I/1S/91 01/11/91 01/19/91
DATE
Room 116 Crawlspace
Figure 9.1.3. Continuous radon levels during the winter follow-up
measurements during various mitigation options at Glenvlew
Elementary, Nashville, TN.
-------
u
CL,
-J
til
>
w
J
2
O
Q
<
OS
Vents Open C/S Press 6-Pt ASD
Vents Closed C/S Depress 4-PtASD
Class (April'90)
Class (Dec/90)
Crawl (April'90)
Crawl (Dec."90)
Figure 9.1.4. Summary of the radon levels in Glenview Elementary classroom
and crawlspace during each of the testing periods, both
Spring/Summer and Winter.
A-69
-------
Figure 9.1.5.
Differential pressures and temperatures in both the classroom
and Che crawlspace during the testing period at Glenview
Elementary, Nashville, TN.
A-70
-------
f^"] - UMf VCHTUJOR
Figure 10.1.1. Partial floor plan showing utility tunnel and room locations
at Lldgerwood Elementary School, Spokane, WA.
A-71
-------
ROOM 139
amy "yr
OFF
LOW MEDIUM
UV SPEED SETTING
HIGH
¦ OA(l<»&)DOOR-CLOSED ~ OA(10^)DOOR-CLOSED
TO OAflOO^jDOOR-OPEN Q OA(10%)DOOR-OPEN
Figure 10.1.2. Room^over-pressures achieved in Room 139 using the unit
ventilator, Lidgervood Elementary School.
A-72
-------
ROOM 140
0,06
0.05
£ 0.04
0.03
A
0
V
r\
v
3
0
1 0.02
v 0.01
0.
-0.01
"ur —
OFF LOW MEDIUM HIGH
UV SPEED SETTING
Hi OA(1O0%)DOOR-CLOSED ~oA<109&)DOOR-CLOSED
S3 OA(100%)DOOR-OPEN Q OA(l 0% )DOOR - OPEN
Figure 10.1.3. Room over-pressures achieved in Room 140 using the unit
ventilator, Lidgerwood Elementary School.
A-73
-------
ROOM 141
| v v"
^ A
T\ A |
izr
iZF^O"
OFF
LOW MEDIUM
Ijy SPEED SETTING
HIGH
¦ OA(10O%)DOOR-CLOSED I I OA(10^ iDOOR-CLOSED
W\ OA(100%)DOOR-OPEN Q OA(l)DOOR-OPEN
Figure 10.1,4. Room over-pressures achieved in Room 141 using the unit
ventilator, Lidgerwood Elementary School.
A-74
-------
ROOM 142
0.06
0.05
u
£ 0.04
;
V
» 0.03
3
0
1 0.02
E
11
V 0-01
ft
-0.01
CT™—Hqnp—^—rrUu
ii
OFF LOW MEDIUM HIGH
UV SPEED SETTING
¦ OA(10G%)DOOR-CLOSED ~ OA(10%)DOOR-CLOSED
OA(100^)DOOR-OPEN Q OA(lD^)DOOR-OPEN
S .1.5, Room over -pressures achieved in Room 142 using the unit
ventilator, Lidgerwood Elementary School.
A-75
-------
.-WWW. - MMTVOflMW
Figure 10,1,6, Location of the suction and test points used during the
subslab communication tests and the radon levels measured at
these points, tidgervood Elementary School, values in pCi/L.
A-76
-------
100
10
0.1
0.01
0.001
Fa(O')
\^SsFb(l')
-
_
\
F«32')
1
i
* Fe(35')
1
0.01
SP=-
0.1 1 10
DISTANCE FROM SUCTION POINT (ft)
_SP=~&5* . SP=-8' __ SP=-16* _
100
SP—24'
Figure 10.1,7. Results of the subslab communication tests, the values of SP
are the vacuum cleaner suction applied to the suction point at
Lidgerwood Elementary School.
A-77
-------
I
- UNTT VtKTlATOft
Figure 10.1.8. Proposed ASD systems at Lidgerwood Elementary School.
A-78
-------
Figure 10,1.9. Cross-section view of the suction points proposed for
Lidgervood Elementary School (the sane design should be used
in Rooms 128 and 129).
A-79
-------
Figure 10.1.10, Summary of Che data measured in Room 139 over Che period
November 29, 1990 through December 3, 1990.
A—80
-------
ROOM 140
RADON LEVEL (pCi/L)
DATA LOST
UV ON PERIODS
TiME door OPEN
Dp-Rm/TUNNEL (Pa)
-100
11/30/90
12/1/90
12/2/90 12/3/90
Figure 10,1.11, Summary of the data measured in Room 140 over the period
November 29, 1990 through December 3, 1990,
A-81
-------
Figure 10.1.12, Summary of the data measured in Room 141 over the period
November 29, 1990 through December 3, 1990.
A-82
-------
100-
90H
80-
70-
60-
50-
40 H
30-
20-
10-
0-
-1 OH
-20-
TUN
RM141
RM139
RM140
OUTSIDE
11/30/90
12/1/90
12/2/90
12/3/90
Figure 10.1.13. Stannary of the temperature data measured in the classrooms and
outside over the period November 29, 1990 through December 3,
1990.
A—83
-------
11/30/90 12/1/90 12/2/90 12/3/90
Figure 10.1.14, Summary of the wind data measured over the period November 29,
1990 through December 3, 1990.
A-84
-------
40-
ROOM 139
20-
-10-
-20-
12/3/90
RADON LEVEL (pCi/L)
12/5/90
12/7/90
Dp-Rm/TUNNEL (Pa)
UV ON PERIODS
% TIME DOOR OPEN
I
12/9/90
-100
Figure 10.1,15. Summary of the data measured In Room 139 over the period
December 3, 1990 through December 9, 1990.
A-85
-------
( ¦ r ! , 1 -1 r
12/3/90 12/5/90 12/7/90 12/9/90
Figure 10.1.16. Summary of the data measured in Room 140 over the period
December 3, 1990 through December 9, 1990.
A-8 6
-------
40
20-
0-
ROOM 141
RADON LEVEL (pCi/L)
•10-
-20-
Dp-Rm/TUNNEL (Pa)
UV ON PERIODS
% TIME DOOR OPEN
12/3/90
12/5/90
12/7/90
12/9/90
Figure 10,1.17. Summary of the data measured In Room 141 over the period
December 3, 1990 through December 9, 1990.
A-87
-------
100-
904
80-
70-
60-
50-
40-
30-
204
10-
0-
-10-
-20-
TUN
RM141
M139
*" NM140
OUTSIDE
12/3/90
12/5/90
12/7/90
12/9/90
Figure 10.1.18. Summary of the temperature data measured in the classrooms and
outside over the period December 3, 1990 through December 9,
1990.
A-88
-------
40
Figure 10.1.19. Summary of the wind data measured over the period December 3,
1990 through December 9, 1990.
A-8 9
-------
12/10/90 12/12/90 12/14/90 12/16/90
Figure 10,1.20, Summary of the data measured in room 139 over the period
December 10, 1990 through December 16, 1990,
A-90
-------
Figure 10.1.21. Summary of the data measured in Room 140 over the period
December 10, 1990 through December 16, 1990.
A-91
-------
Figure 10.1.22, Summary of the data measured in Room 141 over the period
December 10, 1990 through December 16, 1990.
A—92
-------
LU
DC
3
Lli
Q_
2
LU
12/10/90
12/12/90
12/14/90
12/16/90
Figure 10.1.23. Summary of the temperature data measured in the classrooms and
outside over the period December 10, 1990 through December 16,
1990.
A-93
-------
12/10/90 12/12/90 12/14/90 12/16/90
Figure 10.1.24. Summary of Che wind data measured over Che period December 10,
1990 through December 16, 1990.
A-94
-------
12/17/90 12/19/90 12/21/90 12/23/90
Figure 10.1.25. Summary of the data measured in Room 139 over the period
December 17, 1990 through December 23, 1990.
A-95
-------
10,1.26. Summary of the data measured in Room 140 over the period
December 17, 1990 through December 23, 1990.
A-96
-------
Figure 10.1.27 Summary of the data measured in Room 141 over the period of
December 17, 1990 through December 23, 1990.
A-97
-------
12/17/90 12/19/90 12/21/90 12/23/90
Figure 10.1.28. Summary of the temperature data measured in Che classrooms
over the period December 17, 1990 through December 23, 1990.
A-98
-------
40
30
X
a.
Q
LLi
lu 20
o_
a
z
10
MAXIMUM
MEAN
12/17/90
12/19/90
12/21/90
12/23/90
Figure 10.1.29. Summary of the wind data measured over tha period December 17,
1990 through December 23, 1990.
A-99
-------
40
ROOM 139
RADON LEVEL (pCi/L)
Dp-RMmJNNEL (Pa)
UV ON PERIODS
J % TIME DOOR OPEN
! , 5 , U , 1 1 1 1
12/24/90 12/26/90 12/28/90 12/30/90
Figure 10,1.30. Summary of the data measured In Room 139 over the period
December 24, 1990 through December 30, 1990.
A-100
-------
Figure 10.1.31, Summary of the data measured in Room 140 over Che period
December 24, 1990 through December 30, 1990.
A-101
-------
Figure 10.1.32 Summary of the data measured ill Room 141 over the period of
December 24, 1990 through December 30, 1990,
A-102
-------
100
90
80
70
60
50
40
30
20
10H
0
-10
-20
-~\f-
TUN
Afp
VRM141
qHM 139
^M140
OUTSIDE
12/24/90 12/26/90 12/28/90 12/30/90
Figure 10,1,33. Summary of the temperature data measured in the classrooms and
outside over the period December 24, 1990 through December 30,
1990.
A-103
-------
40
30
T
O.
O
UJ 20
Q-
CO
Q
10
MAXIMUM
MEAN
12/24/90
12/26/90
12/28/90
i.
J!/
• f iiiSi
12/30/90
Figure 10.1.34. Summary of the wind data measured over the period December 24,
1990 through December 30, 1990.
A-104
-------
12/31/90 1/2/91 1/4/91 1/6/91
Figure 10.1.35. Summary of the data measured In loom 139 over Che period
December 31, 1990 through January 4, 1991.
£-105
-------
! I I i 7 1 I
12/31/90 1/2/91 1/4/91 1/6/91
Figure 10,1,36. Summary of the data measured, in. Room 140 over the period
December 31, 1990 through January 4, 1991.
A-106
-------
40-
30-
10-
0-
-10-
-20-
12/31/90
ROOM 141
RADON LEVEL (pCi/L)
NO DATA
Dp-RM/TUNNEL (Pa)
UV ON PERIODS
% TIME DOOR OPEN
X
1/2/91 1/4/91
1/6/91
Figure 10.1.37. Summary of the data measured in Room 141 over the period
December 31, 1990 through January 4, 1991,
A-107
-------
tr
o,
JJJ
cc
13
LU
CL
2
LU
100-
90-
80-
70-
60H
50-
40-
30-
20H
10-
0-
-10-
-20-
TUN
RM141
RM139
RM140
OUTSIDE
12/31/90
1/2/91
1/4/91
1/6/91
Figure 10.1.38. Summary of the temperature data measured in the classrooms and
outside over the period December 31, 1990 through January 4,
1991.
A-108
-------
Figure 10.1.39. Summary of the wind data measured, over the period December 31,
1990 through January 4, 1991.
A-109
-------
90-'
%T!ME UV ON
%T;ME DOORS OPEN
RADON LEVEL (pCl/Lj
141-2 13S-2 140-2 139-4 141-3 139-3 141-1 133-1 140-3 140-5 1 41-4 140-4
Room Number - Week
Figure 10.1.40. Correlation of the 8 hour averages of I time UV's oil and %
time doors open with radon levels averaged over same tine
period.
A-110
-------
%TIME UV ON
%T1ME DOORS OPEN
RAOON LEVEL (pCl/L)
139-3 139-4 140-2 141-3 139-2 141-2 140-3 139-1 141-4 140-5 141-1 140-4
Room Number - Week
Figure 10.1.41. Correlation of che 24 hour averages of % cine UV's on and %
time doors open with radon levels averaged over sane tine
period.
A—111
-------
APPENDIX
TABLES
B-l
-------
Table 4.1.1 Radon Concentrations Measured at Barton Elementary School, Ft. Collins, CO.
Room
#
January Screening
Meas Level Type
# Date (pCi/L) Det.
February Follow up
Level Type
Date (pCi/L) Det.
Post-Mitigation Follow up
Level Type
Date (pCi/L) Det.
Media Rm
Media Rm Dup
Work Rm
4
3
2
5
1
Office #6
Kindergarten
Kindergarten Dup
Kitchen
Kitchen Dup
Gym
Gym
Nurse
Teacher Aides
6
7
8
9
10
11
12
Lounge
Main Off. '
Principal
Principal Dup
Coach Off
Art Teach Off
Nusic Rm #6
12/23/91
Average
Minimum
Maximum
6.56
4.84
12.33
7.63
5.86
10.25
3.4 EP
2.9
2.9
3.0
3.0
3.2
3.0
3.0
2.8
3.1
2.7
2.7
2.7
2.9
2.9
2.7
3.0
2.8
3.2
2.6
3.4
2.95
2.60
3.40
-------
Table 4.1.2 Subslab Communication Test Results at Barton
Elementary School, Ft. Collins, CO.
Ap
Suction
Point Fa
(in.W.C)
Suction Pt.
Flowrate
(cfm)
4p
Test Point
Fb (1 ft from
Fa)
(in.W.C)
4p
Test Point
Fc (11 ft
from Fa)
(in.W.C)
Ap
Test Point
Fd (22 ft
from Fa)
(in.W.C)
0.00
0.0
0.000
-0.001
-0.000
-0.75
28.
-0.095
-0.012
-0.002
-1.10
100.
-0.120
-0.014
-0.002
-1.60
>100.
-0.165
-0.019
-0.002
-2.60
>100.
-0.219
-0.024
-0.002
B-3
-------
Table 4.2.1 Radon Concantratlons Measured At Plattarille Elementary School, Plattavlla, CO.
March Serening
August Folkw* up
1990 Alpha Track
Dec 90 HVAC On
D#c 90 HVAC Of!
Percent
March 91 Follow-ij)
Room
Maas
Data
Laval
Type
Data
Laval
Typa
Data
Laval
Type
Data Level
Typa
Data
Laval
Typa
Incraaaa
Data Laval Typa
*
#
fldart
toCI/U
Pat
<3dav)
toO/U
QsL
ttmol
IpCIAJ
QsL
I3davl toCl/U
OA
<3davl
toCI/U
OA
w/HVACOn
Qdari toO/U Pat
Inst Support
1
03/0990
11.1
CC
08/0090
1.9
CC
09/12/90
4.0
AID
12/24/90 8.3
CC
12/2990
7.9
CC
-20.3
03/1V91 0.6 CC
Classroom
2
9.3
2.6
6.7
0.5
4.7 •
Clauroom
3
62
2.8
8.4
6.4
65.6
Classroom
4
9.6
3.4
8.5
4.8
64.8
4.9
Kindergarten
8
93
1.9
•
30
¦
• 7.7
37
106.1
Kindergarten
e
9.9
1.7
¦
3.5
¦
8.6
35
1457
Ctasaroom
7
49
14
8.3
33
191.5
Classroom
8
7.7
1.4
•
4.0
•
7.4
3.1
138.7
6.6 "
Clauroom
Q
4.3
1.5
•
4.2
•
8.2
3.8
1198
68 •
InaL Support
10
10.0
1.9
• 9.8
3.9
151.3
7.5 "
Classroom
11
7.6
1.4
•
4.4
¦
7.6
3.4
123.8
Inst Support
12
6.1
1.6
6.8
3.0
126.7
InaL Support
13
66
1.7
65
3.5
85.7
Inst. Support
14
80
1.8
7.9
3.4
120.6
Clauroom
1S
62
2.2
5.4
4.5
20.0
4,4
ClaMioom
16
30
1.7
• 3.4
2.6
360
Clauroom
17
10.3
26
1
2.6
¦
6.6
4.9
14.3
Clauroom
16
10.3
22
¦
3.1
•
6.4
6.3
66.5
Classroom
19
9.5
36
•
4.1
•
10.2
7,1
437
Clauroom
20
80
2.1
7.8
6.1
27.9
4.6 •
Inst Support
21
0.6
1.1
t 6
1.1
38.4
1.4
IntLSupport
22
1.2
0.9
1.8
1.3
369
1.7 •
Inst Support
**
22
1.2
1.7
1.7
0.0
1.4 •
Inst Support
24
2.1
1.1
1.7
1.2
41.7
14 #
Office
29
67
12
6.6
42
33.3
4.6 '
Offtoe
26
>.1
* 108
10.0
60
7.0 "
Office
27
62
1.0
2.0
2.6
-286
1.4 '
Kitchen
26
6.6
1.0
2.1
1.7
23.6
• 16 #
Gym
29
74
12
•
4 1
•
• 6.4
40
600
Avaraga 6.3 10 3.7 6.3 3.6 64.3 4.6
Minimum 0.6 09 2.6 IB 05 >20.6 1.4
Maximum 11.1 3.6 4.4 10.6 10.0 191.6 7.6
-------
Table 4.2.2 Pressure Field Extensions Measured During Diagnostic Tests
at Platteville Elementary School, Platteville, CO.
Suction
Point
#1
Test Point Location
Suction
Point
#2
Test Point Location
Fa Rm
16
Fb
Fc
Fd
Fa Rm
13
Fb
Fc
Fd
Distance
(ft)
0.06
1
30
60
0. 06
1
25
30
Dp
(in.W.G)
10.0
0. 500
0. 005
0.000
27.0
1.200
0.002
0. 000
15.0
0.798
0. 008
0.000
37.0
1.530
0.003
0.000
20.0
1.024
0.010
0. 000
44 .0
1.750
0.002
0.000
25.0
1. 345
0.012
0. 000
-------
Table 6,1.1. Test matrix for Nokomis Elementary, St Paul, MN.
Test
Number
UV
(On/Off)
TJV OA
(%)
AHU
(On/Off)
AHU OA
<%)
ASD
(On/Off)
Comments
1
On
Normal
On
Normal
On
2
Off
Normal
Off
Normal
Off
3
On
0
On
0
Off
34
On
0
On
0
Off
Filters
Out
4
On
10
On
10
Off
5
On
50
On
50
Off
6
On
Normal
On
Normal
Off
7
On
Normal
On
Normal
On
8
On
Normal
On
Normal
On
Two
Weeks
Later
B-6
-------
Table 6.1.2. Actual outdoor atr flow (eftn) versus damper position for unit
ventilators and AHU unit in Nokomis Elementary, St.Paul, MN.
Room
OA Damper
Percent
Open
<%)
Total
Unit
Flow
(cfm)
OA
Flow
(cfm)
Percent
OA
(%)
106 (UV)
0
900
0
0
10
990
265
27
50
1020
320
31
100
950
358
38
107 (UV)
0
926
0
0
10
1109
420
38
50
1050
650
62
100
1009
660
65
108 (UV)
0
1050
0
0
10
1190
400
34
50
1200
513
43
100
1205
642
53
Office
0
2025
0
0
(AHU)
10
2160
420
19
50
2280
500
22
100
1960
1100
56
B-7
-------
Table 7.1.1 Radon Concentrations Measured atOakmont Elementary School, Columbus, OH,
Winter<1990-91) Scr»ening(HVAC Off) Subslab Source Strengths
Room
Me as Date
level
Type
Date
Level
Typ«
Date
Laval
Type
#
#
(pCi/l)
Det
(pci/q
Oat
(pCI/L)
Det
6
1
15.4
EP
03/22/91
4.3
CC
9
2
16.6
BP
03/22/91
5.3
CC
03/05/91
450
SSS
10
3
20.5
EP
03/22/91
8.3
CC
03/05/91
350
SSS
12
4
19.5
EP
03/22/91
7.2
CC
03/05/91
200
SSS
11
5
19.9
EP
03/22/91
7.2
CC
9
6
17.2
EP
03/22/91
5.9
CC
03/05/91
100
SSS
7
7
15.5
EP
03/22/91
4.7
CC
5
8
12.3
EP
03/22/91
4.7
CC
03/05/91
too
SSS
Office
9
11.3
EP
03/22/91
4.5
CC
Boiler R
10
3.8
EP
03/22/91
26
CC
3
11
11.1
EP
03/22/91
4.8
CC
1
12
12.4
EP
03/22/91
4.9
CC
2
13
11.2
EP
03/22/91
5.3
CC
4
14
11.8
EP
03/22/91
5.8
CC
H'Room
15
03/22/91
4.7
CC
T'Lng
16
11.8
EP
03/22/91
4.7
CC
3 "Bath
17
10,3
EP
03/22/91
5.5
CC
B'Saih
18
10.7
EP
03/22/91
4.0
CC
19
19
5.4
EP
03/22/91
<0.5
CC
20
20
4,5
EP
03/22/91
<0.5
CC
21
21
3.7
EP
03/22/91
<0.5
CC
22
22
5.9
EP
03/22/9!
<0.1
CC
23
23
5.7
EP
03/22/91
5.5
CC
24
24
6.7
EP
03/22/91
<0.5
CC
25
25
6.8
EP
03/22/91
<0.5
CC
Gym
26
10.9
EP
K'chert
27
10.9
EP
03/22/91
5
CC
Couniser
28
10.2
EP
03/22/91
s.e
CC
29
29
9.9
EP
03/22/91
S.4
CC
W'Tunnel
30
03/22/91
5.3
CC
03/05/91
500
SSS
E'Tunnal
31
03/22/91
8.4
CC
03/05/91
730
SSS
C'Tunnel
32
03/22/91
6.2
CC
03/05/91
750
SSS
33
03/22/91
8.3
CC
34
03/22/91
6.1
CC
Averages = 11.1 4.S 398
Highest Value - 20.5 8.4 750
Notes: EP » E—perms
CC = charcoal canister
SSS = subslab sniff
B—8
-------
Table 7.1.2. Fan coil unit flows at Oakmont Elementary,
Columbus, OH.
Room Served by FCUs
Measured
Airflow (cfm)
Design
Airflow (cfm)
1
868 & 601
1700
2
705 & 816
1700
3
1305
1200
4
1260
1200
5
1170
1200
6
1435
1200
7
1407
1200
8
1335
1200
9
1192
1200
10
1210
1200
11
1269
1200
12
1318
1200
Multipurpose Room
3645
4000
Stage
839
1000
Teacher's Lounge
541
450
Music Room
568
700
Principal's Office
345
350
Supply Room
361
300
Conference Room
309
300
Office
476
350
Nurse's Office
308
200
TOTALS
23,283
23,050
B-9
-------
Table 7.1.3 Data logger parameters measured
at Oakmont Elementary School, Columbus, OH.
RADON LEVELS MEASURED WITH A FEMTOTECH:
Room 6
loom 7
Room 3
Room 10
Room 12
Teachers Lounge
East Tunnel
West Tunnel
PRESSURE DIFFERENTIALS MEASURED BETWEEN:
Room 8 and Tunnel(Central)
Room 8 Subslab and Tunnel (Central)
Supply Air to Room 8 and Tunnel (Central)
East Tunnel to Tunnel (Central)
Return Air Walkway to Tunnel (Central)
Tunnel Subslab to Tunnel (Central)
Outside Building to Tunnel (Central)
TEMPERATURES:
Room 8
Supply Room 8
Return Air
Air Mixing Chamber
Subslab in Tunnel
Outside Building
MISCELLANEOUS:
Wind Direction
Wind Speed
Ambient RH
Ra infall
Return Air Damper Position
Outside Air Damper Position
3-10
-------
Table 7.1.4. Test Matrix for Oaksoiyt Elementary School,
Columbus, OH (HVAC operated only part of day).
Test
No.
Duration
HVAC System
Operation (hours)
Return
Air {%)
Outdoor
Air {%)
I
1 week
6:30 am - 4:30 pm
100
0
II
1 week
6:30 am - 4:30 pm
50
50
III
1 week
6:30 am - 4:30 pm
0
100
Notes: FCUs operate when HVAC system operates.
HVAC system hours of operation are approximate.
B-ll
-------
Table 7.3.1 PFE Measurements in Library Area at Fifth Avenue
Elementary School, Columbus, OH.
Test
Point
Approx.
Distance
to suction
point
(feet)
Subslab-to Room
Baseline
Pressure
Differential at
(in. WC)
Subslab-to Room
Pressure
Differential
at 4 in. Vacuum on
Suction at (in.WC)
Sub-
slab
Sniff
pCi/L
b
1
0.000
-0.25
1600
c
66
0.002
0.001
100
d
50
0.001
0.000
200
e
41 '
0.002
0.000
na
f
71
0.002
0.002
2000
S
38
0.000 to 0.001
0.000 to 0.001
700
B-12
-------
Table 7.3.2. PFE Measurements in Multi-Purpose Room
at Fifth Avenue Elementary School.
Test
Point
Approx.
Distance
to Suction
Point
(feet)
Subslab-to Room
Baseline
Pressure
Differential at
(in. wc)
Subslab-to Room
Pressure
Differential
at 4 in.Vacuum
on
Suction at
(In.WC)
Subslab
Sniff
CpCi/L)
h
65
0.000 to -0.001
-0.001 to -0.002
na
i
30
0.000 to -0,001
-0,000 to 0.002
na
j
1
na
na
100
B-13
-------
Table 8.1,1 Radon Screening Measurements in the Rapid City Area
School District, Rapid City, SD.
Site Room Detector Date Tune Date Time Level
# # # Placed Placed Retrieved Retrieved (pCi/L)
Abraham Lincoln Elementary
1
16
2
11
3
12
4
4
5
1 (Kndg)
6
Boiler
7
Prin Off
24587 11/07/90
24610 11/07/90
24612 11/07/90
24609 11/Q7/90
22111 11/07/90
24601 11/07/90
24611 11/07/90
07:31 PM 02/05/91
07:34 PM 02/05/91
07-36 PM 02/05/91
07:45 PM 02/05/91
07:47 PM 02/05/91
07:40 PM 02/05/91
07:42 PM 02/05/91
06:40 PM 36.7
06:42 PM 15.0
06:43 PM 20.4
06:49 PM 7.9
06:48 PM 15.7
06:44 PM 25 J
06:46 PM 10.4
Horace Mann Elementary
1
Office
2
15
3
16
4
7
5
10
6
17
7
Mech.Rm
8
Kndg
22139 11/05/90
17049 11/05/90
22155 11/05/90
22113 11/05/90
22148 11/05/90
24648 11/05/90
13442 11/05/90
22098 11/05/90
06:24 PM 02/04/91
06:28 PM 02/04/91
06:31 PM 02/04/91
0633 PM 02/04/91
0636 PM 02/04/91
06:41 PM 02/04/91
06:43 PM 02/04/91
06:46 PM 02/04/91
04:34 PM 3.9
04:38 PM AS
04:40 PM 5.6
04:35 PM 3.5
04:45 PM 6.2
04:46 PM 5.2
Missing N/D
04:48 PM 12 J
Annie Tallent Elementary
1
16
24632 ¦
11/07/90
0534 PM
02/05/91
05:02 PM
2
Boiler
24649
11/07/90
05-30 PM
02/05/91
05:05 PM
3
5
22151
11/07/90
05:27 PM
02/05/91
05:03 PM
Grand view Elementary
1
12
22099
11/06/90
06:55 PM
02/05/91
04:33 PM
2
10
24617
11/06/90
0653 PM
02/05/91
04:32 PM
3
8
24616
11/06/90
06:51 PM
02/05/91
04:31 PM
4
Health
22107
11/06/90
06:49 PM
02/05/91
04:28 PM
5
Kndg
24645
11/06/90
07:28 PM
02/05/91
04:25 PM
6
Boiler
24621
11/06/90
07:17 PM
02/05/91
04:20 PM
7
6
24635
11/06/90
0730 PM
02/05/91
04:22 PM
6.6
62
5.7
33
3J
42
3.0
6.0
8.1
5.6
(continued)
B-14
-------
Table 8.1.1. Radon Screening Measurements in the Rapid City Area School District,
Rapid City, SD. (continued)
Robbinsdale Elementary School
1 Boiler N/D
E.B. Bergquist Elementary School
1
7
17076
2
6
24638
3
3
24631
4
12
24636
5
9
22029
6
Office
24628
7
A—3
22510
8
Kndg
24636
Valley View Elementary
1 3 24650
2 10 24646
3 Boiler 24640
Thomas Jefferson Elementary
1
1
24641
2
2
22132
3
4
24629
4
6
24634
5
9
22093
6
11
24647
7
16
22102
8
Lunch Rm
24643
N/D
N/D
N/D
N/D
17.7
11/06/90
05:48 PM
02/04/91
06:18 PM
1.1
11/06/90
05:57 PM
02/04/91
06:26 PM
5.4
11/06/90
05:45 PM
02/04/91
06:16 PM
5.2
11/06/90
06:01 PM
02/04/91
06:29 PM
15
11/06/90
05:59 PM
02/04/91
06:28 PM
2.1
11/06/90
0537 PM
02/04/91
06:14 PM
7.0
11/06/90
05:52 PM
02/04/91
06:21 PM
4.4
11/06/90
05:42 PM
02/04/91
06:32 PM
15
11/06/90
11/06/90
11/06/90
06:20 PM
06:23 PM
06:25 PM
02/04/91
02/04/91
mm/9i
06:44 PM
06:47 PM
06:49 PM
7.9
12.7
10.6
11/07/90
05:55 PM
02/05/91
05:30 PM
12.9
11/07/90
05:49 PM
02/05/91
05:32 PM
Missing
11/07/90
06:07 PM
02/05/91
05:35 PM
3.6
11/07/90
05:52 PM
02/05/91
05:34 PM
3.9
11/07/90
06:12 PM
02/05/91
05:17 PM
3.1
11/07/90
06:17 PM
02/05/91
05:24 PM
33
11/07/90
06:22 PM
02/05/91
05:28 PM
IS
11/07/90
06:10 PM
02/05/91
05:25 PM
2.6
B-15
-------
Table 8.1.2 Radon concentrations measured at Abraham Lincoln Elementary
School, Rapid City, SD.
Winter(1990 -91) Screening(HVAC Off) Screening(HVAC On) Subslab Source Strengths
Room Meas
Date
Level
Type
Date
Level
Type
Date
Level
Type
Date
Level
Type
# #
(pCi/L)
Det.
(pCi/L)
Det.
(pCi/L)
Del.
(pCi/L)
Det.
1
1
11/07/90
15.7
ATD
05/03/91
16.1
CC
05/17/91
3.2
CC
2
2
05/03/91
6.9
CC
05/17/91
7.9
CC
07/30/91
2700
SSS
3
3
05/03/91
14.6
CC
05/17/91
6.0
CC
4
4
11/07/90
7.9
ATD
05/03/91
6.6
CC
05/17/91
7.7
CC
07/30/91
1800
SSS
Office
5
05/03/91
8.5
CC
05/17/91
6.0
CC
Gym
6
05/03/91
9.5
CC
05/17/91
5.1
CC
POff
7
11/07/90
10.4
ATD
05/03/91
16.4
CC
05/17/91
9.3
CC
T'Lng
8
05/03/91
8.5
CC
05/17/91
5.2
CC
07/30/91
4500
SSS
9
9
05/03/91
1.3
CC
05/17/91
2.4
CC
B'Room
10
11/07/90
25.5
ATD
05/03/91
3.2
CC
05/17/91
11.2
CC
11
11
11/07/90
15.0
ATD
05/03/91
15.8
CC
05/17/91
1.5
CC
12
12
11/07/90
20.4
ATD
05/17/91
0.6
CC
13
13
05/03/91
34.3
CC
05/17/91
12.2
CC
14
14
05/17/91
4.7
CC
07/30/91
6600
SSS
H'Room
15
05/03/91
9.6
CC
05/17/91
3.8
CC
16
16
11/07/90
36.7
ATD
05/03/91
35.9
CC
05/17/91
14.1
CC
07/30/91
5700
SSS
17—Lib
17
05/03/91
2.9
CC
05/17/91
3.5
CC
18
18
05/03/91
1.5
CC
05/17/91
4.1
CC
19
19
05/03/91
2.1
CC
05/17/91
2.2
CC
20
20
05/03/91
1.9
CC
05/17/91
3.0
CC
Averages =
18.8
10.9
5.7
4260
Highest Value =
36.7
35.9
14.1
6600
Notes: ATD = alpha track detector
CC - charcoal canister
SSS = subslab sniff
-------
Table 8.1.3 Carbon Dioxide Levels Measured at Abraham Lincoln Elementary School.
Number
Room
UV Supply
Room
Meas
Date
Time
Corridor
Open
Level
Level
#
#
Day
Door
Windows
(ppm)
(ppm)
Comments
1
1
05/01/91
11:45 AM
Open
0
700
675
2
O
2
q
05/01/91
11:45 AM
Closed
2
700
475
J
4
O
4
05/01/91
11:45 AM
Closed
0
1600
1500
Office
5
Gym
6
05/01/91
12:00 PM
Open
N/A
1400
N/A
P'Off
7
T'Lng
8
9
9
05/01/91
12:00 PM
Open
0
800
625
B'Room
10
11
11
05/01/91
12:00 PM
Open
0
1200
650
12
12
05/01/91
12:00 PM
Open
1
1050
675
Unoccupied
05/01/91
12:30 PM
Open
0
1225
0
Occupied
13
13
14
14
05/01/91
12:30 PM
Open
0
4000
Off
Initial Measurement
05/01/91
12:35 PM
Open
0
3500
875
5 min later
05/01/91
12:40 PM
Open
0
2800
N/A
10 mln later
05/01/91
12:50 PM
Open
0
1500
N/A
20 mln later
H'Room
15
16
16
05/01/91
01:00 PM
Open
2
1250
1050
17—Lib
17
05/01/91
01:00 PM
Open
0
1075
1075
16
18
19
19
05/01/91
01:00 PM
Open
0
2500
20 20
Note: Unless noted otherwise, C02 measurements
were made either while rooms were occupied or
immediately after the students left.
-------
Table 8.1,4. Test matrix for Lincoln Elementary School,
Rapid City, SD.
Test
No,
Test
Dates
Class
Room
Doors
Unit
Ventilator
Operation
Exhaust Fan
Operation
Outdoor
Air-Damper
Position
ASD
System
Opera-
tion
1
11/18
to
24/91
Normal1
Normal2
Off
Normal3
Off
2
11/25
to
29/91
Normal
Normal
On
Normal
Off
3
12/2
to
6/91
Closed4
Normal
Off
Normal
Off
4
12/9
to
16/91
Closed
Normal
On
Normal
Off
5
12/16
to
20/91
Closed
Normal
Off
Open5
Off
6
12/30
to
1/3/92
Closed
Normal
On
Closed6
Off
7
1/6
to
10/92
Normal
Normal
Off
Normal
On
8
1/13
to
17/92
Normal
Normal
On
Norma1
On
9
1/20
to
24/92
Closed
Normal
Off
Normal
On
10
1/27
to
31/92
Closed
Normal
On
Normal
On
11
12/23
to
27/91
Closed
Off
On
Normal
Off
Notes: 1 Determined by teacher preference
2 On 4:00am - 8:00pm weekdays, off over weekend
3 Controlled by outside/inside temperature
4 Teachers asked to keep closed as much as possible
5 OA daaper mechanically blocked open
6 OA damper mechanically blocked closed*
B-18
-------
Table 9.1
.1
Results of Blower Door Measurements at Glenview Elementary School,
Nashville, TN, (in the crawlspace portion of the school).
Type
Effective
Equivalent
Test
Test
Test
ACH
ACH
L.A.
L.A.
Flow Equation
Location
Conditions
(P/D)
@ 4Pa
@ 50Pa
(sq.in.)
(sq.in.)
C
n
Room 116
Closed
D
0.74
3.91
33.5
63.5
47.29
0.660
Room 116
Closed
P
0.45
10.06
20.5
65.5
13.18
1.228
Room 117
Closed
D
0.64
9.94
28.8
81.0
22.49
1.089
Room 117
Closed
P
0.71
4.21
32.4
63.8
43.17
0.702
Room 118
Closed
D
0.93
5.37
42.3
82.7
57.00
0.694
Room 118
Closed
P
0.51
3.85
23.2
50.0
27.08
0.798
Room 119
Closed
D
0.93
4.72
42.1
78.7
60.89
0.644
Room 119
Closed
P
0.76
2.95
34.5
58.4
57.79
0.537
Crawl
Closed
P
0.68
2.48
82.5
136.3
143.59
0.510
Crawl
Open
P
2.08
5.81
250.7
377.0
503.35
0.407
Room Averages
0.71
5.63
32.16
67.95
* Notes: Rooms Closed implies Windows and Doors Closed
Crawl Closed implies Crawlspace Vents Closed
Crawl Open implies Crawlspace Vents Open
Test Type = D is Depressurization
Test Type = P is Pressurization
-------
Table 9.1.2 Summary of parameters measured at the crawlspace
part of Glenview Elementary, Nashville, TN.
Parameters
Locations
Differential Pressure
Room 116 to Outdoors
Room 116 to crawl-
space
Room 116 to Subpoly
Radon
Room 116
Crawlspace
Temperature
Room 116
Crawlspace
Soil
Outdoors
Wind Speed and
Direction
Outdoors
Relative Humidity
Outdoors
Rainfall
Outdoors
B-20
-------
TABLE 10.1.1 LIDGERW00D SCHOOL SPOKANE, WA
DATA TAKEN: AUG 22, 1990
ROOM 139
DIFFERENTIAL PRESSURE MEASUREMENTS (in.U.C.)
ROOM TO OUTDOORS
HALLWAY DOOR: CLOSED
UNIT VENTILATOR SPEED SETTING:
OA DAMPER POSITION OFF LOW MEDIUM HIGH
OPEN (100%)
-0.001 0.01
HALLWAY DOOR: OPEN
OA DAMPER POSITION
-0.001
0.009
OFF
0.053
0.012
0.054 0,056 CLOSED (10% Open)
UNIT VENTILATOR SPEED SETTING:
LOW MEDIUM HIGH
OPEN (100%)
-0.001
¦0.001
0.003
•0.002
AIR QUANTITY MEASUREMENT (cfm)
OA DAMPER POSITION LOW
-0.001 -0.001
-0.001
0 CLOSED (10% Open)
MEDIUM
HIGH •
OPEN (100%)
OUTDOOR AIR 460 470 500
SUPPLY AIR 1175 1306 1285
CLOSED (10% Open)
OUTDOOR AIR 30 47 109
SUPPLY AIR NA NA NA
PERCENT OUTDOOR AIR
OA DAMPER OPEN 39% 36% 39%
OA DAMPER CLOSED 3% 4% 8%
OA PER STUDENT (CFM - BASED ON 20 STUDENTS)
OA DAMPER OPEN 23 24 25
OA DAMPER CLOSED 2 2 5
LEAKAGE AREA (M2)- 0.046 0.047 0.049
AVG LEAK AREA(M2)- 0.047
AVG LEAK AREA (IN2)- 73.2
OBSERVATIONS: Room 139 could be pressurized with the unit ventilator,
regardless of the OA damper position, but only when the hallway
door was closed. This room is the library and it does not have
an exhaust vent like the other rooms, thus it is easier to
pressurize, however pressurization was not possible with the
hallway door open.
B-21
-------
TABLE 10.1.2 LIDGERUOOD SCHOOL SPOKANE, WA
DATA TAKEN: AUG 22, 1990
ROOM 140
DIFFERENTIAL PRESSURE MEASUREMENTS (in.W.C.)
ROOM TO OUTDOORS
HALLWAY DOOR: CLOSED
OA DAMPER POSITION OFF
OPEN (100%)
CLOSED (10% Open)
HALLWAY DOOR: OPEN
OA DAMPER POSITION OFF
0
0
UNIT VENTILATOR SPEED SETTING:
LOW MEDIUM HIGH
0.02
¦0,002
0.021
-0.001
0.024
-0.002
UNIT VENTILATOR SPEED SETTING:
LOW MEDIUM HIGH
OPEN (100%) 0.001
CLOSED (10% Open) 0.001
AIR QUANTITY MEASUREMENT (cfm)
OA DAMPER POSITION LOW
OPEN (100%)
OUTDOOR- AIR
SUPPLY AIR
CLOSED (10% Open)
OUTDOOR AIR
SUPPLY AIR
PERCENT OUTDOOR AIR
OA DAMPER OPEN
OA DAMPER CLOSED
OA PER STUDENT (CFM
OA DAMPER OPEN
OA DAMPER CLOSED
LEAKAGE AREA (M2)-
AVG LEAK AREA( M2 ) -
AVG LEAK AREA (IN2)-
361
1200
45
1090
0
¦0.004
MEDIUM
438
1263
23
1135
30%
4%
351
2%
BASED ON 20 STUDENTS)
18 22
2 1
0.059
0.065
101.1
0.070
-0.003
-0.002
HIGH
449
1380
44
1197
33%
4%
22
2
0.067
-0.001
-0.008
OBSERVATIONS: Room 140 could be pressurized with the unit ventilator, only
with the OA damper in the fully open position, and only when the
hallway door was closed. This room has a passive vent and is
more difficult to pressurize.
B-22
-------
TABLE 10.1.3 L1DGERWOOD SCHOOL SPOKANE, WA
DATA TAKEN: AUG 22, 1990
DIFFERENTIAL PRESSURE MEASUREMENTS (in.W.C.)
ROOM TO OUTDOORS
HALLWAY DOOR; CLOSED
ROOM 141
OA DAMPER POSITION
OPEN (100*)
CLOSED (10% Open)
HALLWAY DOOR: OPEN
OA DAMPER POSITION
OFF
0
-0.003
OFF
UNIT VENTILATOR SPIED SETTING:
LOW MEDIUM HIGH
0.03
-0.002
0.034
-0.001
0.036
-0.003
UNIT VENTILATOR SPEED SETTING:
LOW MEDIUM HIGH
OPEN (100%)
CLOSED (10% Open)
-0.002
-0.002
AIR QUANTITY MEASUREMENT (cfm)
OA DAMPER POSITION LOW
OPEN (100%)
OUTDOOR AIR
SUPPLY AIR
CLOSED (10% Open)
OUTDOOR AIR
SUPPLY AIR
-0.005
-0.002
MEDIUM
495
1001
72
NA
580
1097
87
NA
0.001
-0.003
HIGH
657
1160
94
NA
•0.001
¦0.003
PERCENT OUTDOOR AIR
OA DAMPER OPEN
OA DAMPER CLOSED
49%
7%
53%
8%
57%
8%
OA PER STUDENT (CFM - BASED ON 20 STUDENTS)
OA DAMPER OPEN
25
29
33
OA DAMPER CLOSED
4
4
5
LEAKAGE AREA (M2)-
0.066
0.073
0.080
AVG LEAK AREA(M2)- 0.073
AVG LEAK AREA (IN2)- 113.0
OBSERVATIONS: Room 141 could be pressurized with the unit ventilator, only
with the OA damper in the fully open position, and only when the
hallway door was closed. This room has a wind turbine exhaust
and is more difficult to pressurize.
B-23
-------
TABLE 10.1.4 LIDGERWOOD SCHOOL SPOKANE, WA ROOM 142
DATA TAKEN: AUG 22, 1990
DIFFERENTIAL PRESSURE MEASUREMENTS (in.W.C.)
ROOM TO OUTDOORS
HALLWAY DOOR: CLOSED
OA DAMPER POSITION
OFF
UNIT VENTILATOR
LOW MEDIUM
SPEED SETTING
HIGH
OPEN (100%)
CLOSED (10% Open)
0
-0.003
0.03
-0.002
0.034
-0.001
0.036
-0.003
HALLWAY DOOR: OPEN
OA DAMPER POSITION
OFF
UNIT VENTILATOR
LOW MEDIUM
SPEED SETTING
HIGH
OPEN (100%)
CLOSED (10% Open)
-0.002
-0.002
-0.005
-0.002
0.001
-0.003
-0.001
-0.003
AIR QUANTITY MEASUREMENT (cfm)
OA DAMPER POSITION
LOW
MEDIUM
HIGH
OPEN (100%)
OUTDOOR AIR
SUPPLY AIR
226
1123
230
1218
251
1362
CLOSED (10% Open)
OUTDOOR AIR
SUPPLY AIR
150
1078
160
1250
184
1306
PERCENT OUTDOOR AIR
OA DAMPER OPEN
OA DAMPER CLOSED
20%
14%
19%
134
18%
14%
OA PER STUDENT (CFM - BASED
OA DAMPER OPEN
OA DAMPER CLOSED
ON 20 STUDENTS)
11 12
8 3
13
9
LEAKAGE AREA (M2)-
AVG LEAK AREA(M2)-
AVG LEAK AREA (IN2)-
0.030
0.030
46.2
0.029
0.031
OBSERVATIONS: Room 142 could be pressurized with the unit ventilator, only
with the OA damper in the fully open position, and only when the
hallway door was closed. This room has a wind turbine exhaust
vent is more difficult to pressurize, although the turbine was
inoperable during these measurements. The OA damper appears not
to fully open.
B-24
-------
Table 10.1.5 Subslab Communication Test Results At
Lidgerwood Elementary School, Spokane, WA on August 21, 1990.
Fa
Flow
Fb
Fc
Fd
Fe
Suction
Rate
V
20'
32'
35'
Pressure
at Fa
from Fa
from Fa
from Fa
from Fa
(in.W.C.)
(cfm)
(in.W.C.)(in.W.C.)
(In.W.C.;
Xln.W.C.)
0.0
0
0.00
-0.003
0.005
0.005
-3.0
8
-0.50
-0.020
0.003
0.002
-6.5
14
-1.00
-0.035
0.002
0.003
-8.0
17
-1.15
-0.036
0.003
0.003
-16.0
24
-1.76
-0.056
0.003
0.003
-24.0
123
-2.43
-0.075
0.002
0.003
B-25
-------
Table 10.1.6 Radon levels and percent time classroom doors were open at Udgeiwood School,
averaged over both the 6chool day (8 hours) and over the 24 hour period.
Room 139 Room 140 Room 141
fivg. Radon Pug. Radon Ak/g.Radon
(%)Door Open (%)UVOn Le/el (pCl/l) (%)DoorOpen (%)UVOn La/el (pCI/g (%)DoorOpen (%)UV On Lei/el (pCI/l)
Pay
Dale
24Hrc
8Hre
OHra
24Hrs
9Hre
24Hre
BHre
24Hrs
8Hra
24Hr»
8Hrg
24Hre
QHre
24Hre
8Hre
24Hrs
8Hre
Fri
11/30/90
190
1000
52 1
100
16
0.6
202
56 1
52.1
100
N/D
N/D
158
46.9
52.1
100
22
0.8
Sal
12/01/90
00
52 1
00
0
162
19.4
00
0.0
0
0
N/D
N/O
0.0
0.0
0
0
17.8
19.4
Sun
12/02/90
00
00
0
0
6.2
4.7
00
0.0
0
0
N/D
N/O
0.0
0.0
0
0
2.5
4.7
Mon
12/03/90
17.2
49.3
35.4
66.7
21
1.5
30.0
56.0
35.4
66.7
N/D
N/D
39.7
39 2
35.4
66.7
51
1.0
Tub
12/04/90
30.1
79.3
52.1
100
7.6
4.2
21.8
55.4
52.1
100
N/D
N/D
23.4
689
52.1
100
8.6
2.7
Wed
12/05/90
21.6
63.9
52.1
100
0.4
0.3
27.2
75.6
52.1
100
N/D
N/D
17.8
33 6
52.1
100
0.1
0.1
Thu
12/06/90
27.0
809
43.8
94 4
12
1.7
19.6
45.9
43.8
94.4
N/O
N/O
27.8
76.1
438
94.4
2.5
2.9
Ed
12/07/90
248
49.7
45.5
94.4
1.7
1.8
33.5
637
458
944
N/D
N/D
18.6
4±fi
458
MA
6.3
24
/Weragas=
24 2
64.6
45lB
91.1
2.6
19
26.4
59.7
45.8
91.1
25.4
52.4
45.6
91.1
4.5
1.7
Sal
12/08/90
00
0.0
0
0
8.2
9.0
0.0
0.0
0
0
N/O
N/O
0.0
0.0
0
0
N/O
N/O
Sun
12/09/90
0.0
00
0
0
10.6
10.3
0.0
0.0
0
0
N/D
N/D
0.0
0.0
0
0
17.4
17.0
Mon
12/10/90
1.9
4.1
77.1
100
53
1.6
5.1
12.6
77.1
100
N/D
N/D
16.3
43 7
77.1
100
7.5
1.6
Tue
12/11/90
1.5
4.4
too
100
0.3
02
8.2
24.3
100
100
N/D
N/D
16.5
47.5
100
100
0.1
0.1
Wed
12/12/90
3 0
8.8
100
100
0.5
0.6
7.5
20.2
100
100
N/D
N/D
9.0
18.7
100
100
0.4
0.4
Thu
12/13/90
3.5
10.3
100
100
05
0.7
8.0
233
100
100
1.9
1.3
11.8
34.7
100
100
0.5
0.7
ErJ
12/14/90
34
10.0
66 7
88.9
03
03
10.4
288
66.7
88.9
3.7
2J
5.4
1*4
66.7
86 9
0.4
AmigiiM
2.6
7.5
eae
97.8
1.4
0L7
7.9
21.9
88.8
97.8
1.1
0.8
11.8
32.0
88.8
97.8
22
0l6
Sal
12/15/90
0.0
0.0
0
0
0.8
07
0.0
0.0
0
0
9.8
10.4
0.0
0.0
0
0
18.7
19.9
Sun
12/16/90
0.0
0.0
0
0
04
0 4
0.0
0.0
0
0
1.3
0.9
0.0
0.0
0
0
3.9
2.8
Mon
12/17/90
28.2
84.4
50
100
28
58
13.1
21.2
50
100
46
5.4
14.4
39.1
50
100
3.9
2.4
Tue
12/18/90
28.2
84 5
43.8
94.4
08
13
17.4
43.1
438
94 4
1.3
1.0
13.0
38.7
43.8
94.4
0.3
0.5
Wed
12/19/90
1.2
2.8
31.3
5.6
0.2
02
30
4.9
31.3
5.6
1.4
1.6
3.0
5.8
31.3
6.6
0.1
0.2
Thu
12/20/90
0.0
0.0
37.5
11.1
02
0.1
65.0
88.8
37.5
11.1
1.5
1.3
60.9
76.4
37.5
11.1
0.3
0.3
Ed
12/21/90
-------
Table 10.1.7 Weakly average vafuas of percent tima classroom doors open, percent tlma UVs were on
and radon levels at Udgerwood School over tile testing period.
Avg.Radon
Week Week Room- (%)Door Open (%)UVOn Laval (pCi/L)
of # Week 24Hrs BHrs 24Hrs BHrs 24Hrs 8Hrs
Sortad bv Room Numbf
12/03/90
1
139-1
24.2
84.6
45.8
911
2.8
1.9
12/10/90
2
138-2
2-0
7.5
68.6
97.8
1.4
0.7
12/17/90
3
139-3
11.5
34.3
38.8
43.3
0.9
1.8
12/24/90
4
138-4
0.3
0.9
45.8
40.0
0.9
1.0
12/31/90
S
138- 5
15.2
41.8
27.1
48,6
N/0
N/0
12/03/90
1
140-1
28,4
59.7
4S.8
91.1
N/0
N/0
12/10/90
2
140-2
7.9
21.9
68.8
97,8
1.1
0.8
12/17/90
3
140-3
33.3
51.8
38.11
*3.3
2.5
2.6
12/24/90
4
140-4
$4.6
60.0
45.6
40.0
8.7
11.3
12/31/90
5 .
140-5
25,1
45.4
27.1
46.6
4.3
3.7
12/03/90
1
141-1
25.4
52.4
45.8
91.1
4.5
1.7
12/10/90
2
141-2
11.8
32.0
as. a
97-8
2.2
Q.6
12/17/90
3
141-3
31.8
52.0
aa. a
43.3
1.2
1.1
12/24/90
4
141-4
54.5
30.0
45.8
40.0
3.3
3.9
12/31/90
S
141-5
28.7
53.9
27.1
48.6
N/0
N/D
Sorted bv B hr Radon Values
12/31/90
5
138-5
15.2
41.8
27.1
48.6
N/D
N/0
12/03/90
1
140-1
26.4
59.7
45.8
91.1
N/0
N/D
12/31/90 "
5
141-5
28.7
53.9
27.1
48.6
NfO
N/D
12/10/90
2
141-2
11.B
32.0
88.8
97.8
22
0.6
12/10/90
2
139-2
2.5
7.5
88.6
97.8
1.4
0.7
12/10/90
2
140-2
7.9
21-9
88.8
97.8
1.1
0.8
12/24/90
4
139-4
0.3
0.9
45.8
40.0
0.9
1.0
12/17/90
3
141-3
31.8
52.0
38.8
43.3
1.2
1.1
12/17/90
3
139-3
11.5
34.3
38.S
43.3
0.9
1.6
12/03/90
1
141-1
25.4
52.4
45.8
91.1
4.5
1.7
12/03/90
1
139-1
24.2
64.8
45 6
91.1
2.8
1.9
12/17/90
3
140-3
33.3
51.6
38 8
43.3
25
2.8
12/31/90
S
140-5
25.1
45.4
27.1
48.6
4.3
3.7
12/24/90
4
141-4
54.8
60.0
45.8
40.0
3.3
3.9
12/24/90
4
140-4
54.6
60.0
45.8
40.0
B.7
11.3
Sorted bv 24 hi Radon Values
12/31/90
5
139-5
15.2
41.8
27.1
48.6
N/0
N/D
12/03/90
1
140-1
26.4
59.7
45.8
91,1
N/0
N/D
12/31/90
5
141-5
28.7
53.9
27.1
48.6
N/D
N/D
12/17/90
3
139-3
11.5
34.3
38.6
43.3
0.9
1.6
12/24/90
4
139-4 •
0.3
0.9
45.6
40.0
0.9
1.0
12/10/90
2
140-2
7.9
21.9
sa.a
97.8
1.1
0.8
12/17/90
3
141-3
31.8
52.0
38.8
43.3
1.2
1.1
12/10/90
2
138- 2
2.6
7.5
68.8
97.8
1.4
0.7
12/10/90
2
141-2
11.8
32.0
88.8
97.8
2.2
0.6
12/17/90
3
140-3
33.3
51.6
38.8
43.3
2.5
2.8
12/03/90
1
138- 1
24.2
64.6
45.8
91.1
28
1.9
12/24/90
4
141-4
54.8
80.0
45.8
40.0
as
3.9
12/31/90
5
140-5
25.1
45.4
27.1
48.6
4.3
3.7
12/03/90
1
141-1
25.4
52.4
45.6
91.1
4.5
1.7
12/24/90
4
140-4
54.8
60.0
45.8
40.0
8.7
11.3
B-27
-------
TABLE i\lt Coik>c*t«tDi«iic*>CtaittMfC^fito*RMuM
PtfGflrtt
Oup.
3W-
School
Boom
CfcnHtor
2P
Stot
Stew
CntEfT
Average
D«*.
w
D
No.
NumOw
Code
Dam
Pais
fcC¥U
{2Sig m*)
fcCI/t)
fcCJ/U
KWLSDiOiOl
1
117125
57701
08*13*1
05/05*1
18>2
2.6
KWLSO1C101
1
117859
57701
OSAJ301
0S*B*1
18
&1
161
01
06
KWLSOiOi04
4
119115
5770}
06/17/91
35/19*1
7.6
3-8
K*ISD10104
4
118060
57701
0*17*1
06/16*1
7,5
34
7.7
02
2.6
KWLSD10116
16
117908
57701
o&o&si
OA/OS* 1
33.6
1.6
Kwusoione
18
117806
57701
05W3*1
0&Q9*1
36-2
1.7
35,9
2.3
&4
KWisoion®
19
118127
57701
08/17/91
05/19*1
14,1
2.4
kwiscmchs
IS
110167
57701
»17*1
09/19*1
14.1
2.4
14.1
as
00
KWLS010201
1
118246
37701
0&O3*1
O&Wl
1.9
13
KWLS010201
1
118W7
57701
03*0*1
09*95*1
1.6
111
1.6
ai
*2
KWIS010201
1
118047
57701
05*17*1
39/16*1
1.7
as
KWLSD102D1
1
117886
57701
09/1761
05/18*1
U
10.8
1.8
ao
26
KWLSDlC2i9
18
118227
57701
OStt&SI
05^05*1
8-5
3.9
KWLS01G219
19
117767
57701
06*0*1
6.7
XS
66
0.1
1.2
KWUSO10218
18
118106
57701
06/17*1
05/19*1
17.4
2.2
KWLS010219
16
118068
57701
G»17*1
05/16*1
16.9
2L4
17.0
04
2.7
KWLS01Q301
1
118204
5770!
03X0*1
05*»*1
ZS
9.9
KWLSD10301
1
118296
5770!
09/03*1
os*a*i
2
106
^1
ai
4.8
KWLS010301
1
117961
57701
05^17*1
05/1&61
1,1
15
KWLSD10301
1
117900
57701
06/17*1
05/19*1
0.6
17.7
IjQ
01
10.0
KWLS01G313
16
118210
57701
0S*5a*i
95*35*1
as
0
KWISD10318
16
118183
57701
05/03*1
05ASS1
0.S
0
as
no
ao
KWUSO10319
16
118000
57701
OS/17*1
OS/l&fil
0.3
0
KWLS010316
16
118001
57701
05/17*1
05/16*1
0.6
26.5
ae
ai
61
KWLSD10406
S
118167
57701
05*1191
05/0&61
1
19.7
KVVLSD1&406
s
118203
57701
08/03*1
0&®5*t
0.6
18.8
f.G
Oi
5.3
KWLSD1O*O0
s
118068
57701
05/17*1
&1801
9.8
21,4
KWLSD10O6
6
118082
57701
05/17*1
05/16*1
07
20.3
o.a
3.1
a?
KWLS010412
IS
118213
57701
9&0&91
05/05*1
t.4
14,6
KWLSD10412
12
118186
57701
05/03*1
06/05*1
1.2
17,6
1.3
01
7.7
KWIS01O412
12
118061
57701
05/17*1
05/16*1
0.6
32.3
KWLSDi04t2
12
118060
57701
06/17*1
06/16*1
0.6
22.4
07
01
14.3
KWLSO10413
13
118008
57701
09/17*1
3*19*1
0.8
20
KWISD10413
13
118026
57701
OS'17431
06/16*1
0.8
29.7
ae
0.0
ao
KWLS01C50S
6
113272
57701
05/03*91
35/05*1
1.8
12.7
KWISD1C606
6
118273
57701
05/03*1
06/06*1
1.8
11.3
10
00
0.0
KWL30'C60S
S
118034
57701
05/17*1
05/18*1
9.5
3
KWLS01G5OS
a
118014
57701
06/17*1
05/16*1
09
0
05
00
ao
KWlflOtQSH
11
118264
57701
05/03*1
0,9
0
KWLS01G511
i 1
118263
57701
osoa*i
05/05*!
as
0
0.5
0.0
ao
KWLSD10511
11
117693
57701
05/17* f
35/19*1
as
0
KWLSDtGSlt
11
118033
57701
09/17*1
o&iaei
as
0
0-5
ao
0.0
KWISO1051S
ts
118215
57701
09^03*1
05/05*1
14
6.4
KWLSD1G518
13
118236
57701
05/03*1
os*s*i
17
a?
ae
01
4.2
KWLSP10519
18
118016
57701
08/17*1
»/i«*i
4.5
5.S
KWLS010518
10
117866
57701
03/17*1
0*19*1
4.1
8
4.3
02
4.7
KWLSD10523
23
117966
57701
05/17*1
25/18*1
05
0
KWLS010523
23
118026
57701
05/17*1
05/19*1
05
0
0.5
0.0
ao
KW-S010524
24
118218
57701
05*33*1
05/05*1
as
0
KWLSD 50524
24
118278
57701
05*0*1
05,05*1
0.8
21.2
a?
02
23.1
KWUS01071Q
10
117668
57701
05/31*1
osaasi
18,4
16
KWLSO1071Q
10
117649
17701
06/31*1
06/02*1
17.8
5.8
19.0
04
12
KWLSOWO
10
118064
57701
05/31*1
05^2*1
8
ia2
KWLS01C81G
10
118038
57701
06/31*1
05*C*1
9.1
a.8
8.6
3.0
3.4
KWLSD2010"
1
118437
57790
05/10*1
96/13*1
0.6
14.6
KWUSD20101
1
118466
57780
05/10*1
04/13*1
a*
176
0.9
0.0
ao
KWISD20108
a
118417
57790
09/10*1
96/13*1
1
16.2
KWLSO20106
8
118383
57790
05/10*1
05/13*1
i.i
16.6
1.1
01
4.8
KWLSD20115
15
118427
57790
05/10*1
06/13*1
5.3
4-5
KWLS02O115
15
118426
57790
05/10*1
05/13*1
5
4.7
%2
02
zo
M£D20i2l
21
116478
57790
06/10*1
09/13*1
as
0
KWLS02Q12!
21
116364
57790
05/10*1
05/13*1
as
0
0.5
ao
00
KWLS020134
34
118394
57790
06/1001
06/13*1
u
115
KWLS02C134
34
118415
57790
05/10*1
05/13*1
1.9
9.7
1.5
0.Q
ao
KWLS02015Q
50
118474
57790
09/10*1
05/13*1
1.2
11.7
KWLS32Q150
50
118473
57790
08/10*1
96/13*1
1.4
11.6
1.3
gn
7-7
«WLS020157
57
116403
57790
05/10*1
0*13*1
09
0
KWLSD20I57
57
118401
57700
06/10*1
39/13*1
as
0
0.5
00
00
KWLSO20156
53
116401
57790
05/10*1
09/13*1
1.9
9.3
KWLS020158
58
118402
57790
05/10*1
99/13*1
1.8
10.1
1.6
oli
Z7
KWLS02C173
73
118*40
57790
09/10*1
05/13*1
Z2
6-6
KWLSD20173
73
118441
57790
05/10*1
05/13*1
2.4
8
2.3
ai
4,3
Tstai Nu mb«f of CCs »
72 Average for aJI Meaiuramenti
¦1
02
3.9
Numb*- of Goitacatao Psln
m
36
High
¦
2.3
23.1
low
.
ao
ao
Avenge for Value* > 4 pOA.
¦
13.5
ao
High
m
mo
6.4
Low
m
4.3
ao
Footed Esalrrwfcaf Vutencas
m
0.56
B-28
-------
TABLE 11.4.1
Calibrations of the Continuous Radon Monitors
Cal.
+ -
Cal.
Percent
Model
Serial
Cai.
Factor
1 sigma
Cal.
Factor
1 slgma
Change
No.
No.
Date
(cpm/pCi/L)
(cpm/pCi/L)
Date
(cpm/pCI/L)
(cpm/pCi/L)
Cal.Fact.
R210F
88R210F0165
07/21/89
0.28
0.01
11/01/91
0.28
0.01
0.0
R210F
88R210F0172
08/31/89
0.27
0.01
11/01/91
0.29
0.01
-7.4
R210F
91R210F0413
02/21/91
0.30
0.01
11/23/91
0.31
0.01
-4.0
R210F
91R210F0414
02/21/91
0.28
0.01
10/27/91
0.29
0.01
-3.2
R210F
91R210F0415
02/21/91
0.30
0.01
11/24/91
0.29
0.01
2.0
R210F
91R210F0416
02/21/91
0.30
0.01
10/28/91
0.29
0.01
3.3
R210F
91R210F0417
02/21/91
0.30
0.01
10/29/91
0.30
0.01
-1.4
R210F
91R210F0418
02/21/91
0.29
0.01
10/29/91
0.29
0.01
0.7
R210F
91R210F0419
02/14/91
0.30
0.01
10/27/91
0.30
0.01
0.7
R210F
91R210F0420
02/23/91
0.29
0.01
11/24/91
0.31
0.01
-5.8
R210F
91R210F0421
02/23/91
0.28
0.01
10/29/91
0.28
0.01
-1.4
R210F
91R210F0422
02/23/91
0.29
0.01
11/24/91
0.28
0.01
1.8
R210F
91R210F0423
02/23/91
0.27
0.01
11/27/91
0.31
0.01
-17.0
R210F
91R210F0424
02/23/91
0.29
0.01
11/26/91
0.31
0.01
-6.5
R210F
91R210F0425
02/23/91
0.30
0.01
11/26/91
0.28
0.01
5.4
R210F
91R210F0426
02/23/91
0.30
0.01
11/26/91
0.32
0.01
-5.6
R210F
91R210F0427
02/23/91
0.30
0.01
10/29/91
0.30
0.01
-1.4
R210F
91R210F0428
02/27/91
0.28
0.01
10/29/91
0.29
0.01
-5.1
------- |