PB91-233254
Cost and Effectiveness of Radon Resistant Features in
New School Buildings
Infiltec, Falls Church, VA
Prepared for:
Environmental Protection Agency, Research Triangle Park, NC
1991

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a ,p pr, _ n no/1 TECHNICAL REPORT DATA
.tt i_. tj rv L 1 0 C\J (/'lease read luaruetiotis on the reverie before coin/ilclu
1 HLfORT NO 2
EPA/600/D-91/207
3 f rD7 1 "4JJ^ 3H
4 TITLE ANO SUBTITLE
Cost and Effectiveness of Radon Resistant Features
in New School Buildings
5 REPORT DATE
6 PERFORMING ORGANIZATION CODE
7 AUTHOR(S)
A.B.Craig (EPA), K.W. Leovic (EPA), and
D. W. Saum (Infiltec)
8 PERFORMING ORGANIZATION REPORT NO
9 PERFORMING ORGANIZATION NAME AND ADDRESS
Infiltec
Falls Church, Virginia 22041
10 PROGRAM ELEMENT NO
11 contract/grant NO
68-D0-0097, Task 2
(Sandy Cohen and Associates)
12 SPONSORING AGENCY NAME AND ADORFSS
EPA, Office of Research and Development
Air and Energy Engineering Research Laboratory
Research Triangle Park, North Carolina 27711
13 TYPE OF REPORT AND PERIOD COVERED
Published paper, 11/90 - 6/91
14 SPONSORING AGENCY CODE
EPA/600/13
15 supplementary notes y\£ERL Droject officer is Kelly W. Leovic, Mail Drop 54. 919/541-
7717. Presented at ASHRAE Conference, IAQ91, Washington, DC, 9/2-5/91.
i6 abstract paper describes initial results of a study of several schools with radon
resistant features that were recently constructed in the northeastern U.S. These
designs generally are based on experience with radon mitigation in existing houses
and schools and radon-resistant new construction. The study was limited to slab-on-
grade schools where the most common radon resistant school design is active subslab
depressurization (ASD). The additional construction costs for eight schools built with
ASD ranged from $3 to Sll/sq m of slab area. The radon contractors who designed
these systems have tended to overdesign the radon reduction systems in the absence
of specific written guidance to follow to lessen potential liability in the event of sys-
tem failure. Design features include detailed sealing of all slab cracks, multiple ex-
haust stacks, and extensive subslab piping. Recent EPA research on radon mitigation
suggests that simpler ASD systems may provide sufficient radon resistance in new
buildings at lower costs. Components of a specification for radon resistant school con-
struction are discussed, based on comments from radon system designers. Another
school being studied was built with a heating, ventilation, and air-conditioning (HVAC;
pressurization radon control system, and considerations for this type of system are
examined.
,7 key WORDS ANO DOCUMENT ANALYSIS
3 DESCRIPTORS
b identifiers/open enoeo terms
c COSATl ("icld/Group
Pollution
Radon
School Buildings
Slabs
Design Criteria
Pollution Control
Stationary Sources
Subslab Depressurization
13B
07 B
13M, 051
13 C
14G
18 DISTRIBUTION STATEMENT
Release to Public
19 SECURITY CLASS (7/iit Report)
Unclassified
21 NO OF PAGES
13
20 SECURITY CLASS (Till! pa/H-1
Unclassified
77 PRICE
CP/1 form 2220 1 (9 73)

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PB91-23325H
EPA/600/D-91/207
For presentation at ASHRAE IAQ'91 Healthy Buildings
COST AND EFFECTIVENESS OF RADON RESISTANT FEATURES IN NEW
SCHOOL BUILDINGS
By:
A.B. Craig and Kelly W. Leovic
U.S. Environmental Protection Agency
Air and Energy Engineering Research Laboratory
Research Triangle Park, North Carolina 27711
and
David W. Saum
Infiltec
Falls Church, Virginia 22041
ABSTRACT
Recent concerns over elevated levels of radon in existing buildings have prompted the
design and construction of a number of school buildings which either are radon-resistant or
incorporate features that facilitate post-construction mitigation if needed. This paper describes
initial results of a study of several schools with radon resistant features thai were recently
constructed in the northeastern U.S. These designs are generally based on experience with radon
mitigation in existing houses and schools and radon-resistant new house construction.
The study was limited to slab-on-grade schools where the most common radon resistant
school design is active subslab depressurization (ASD). The additional construction costs for
eight schools built with ASD ranged from $3 to $11 per square meter of slab area. The radon
contractors who designed these systems have tended to overdesign the radon reduction systems
in the absence of specific written guidance to follow to lessen potential liability in the event of
system failure. Design features include detailed sealing of all slab cracks, multiple exhaust
stacks, and extensive subslab piping.
Recent EPA research on radon mitigation suggests that simpler ASD systems may provide
sufficient radon resistance in new large buildings at lower costs. Components of a specification
for radon resistant school construction are discussed, based on comments from radon system
designers. Another school being studied was built with a heating, ventilation, and air-
conditioning (HVAC) pressunzation radon control system, and considerations for this type of
system are examined.

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INTRODUCTION
If a new school is built in an area where elevated radon concentrations have been
identified, the need to design ihe school to be radon resistant (or easily mitigated if excessive
levels of radon are found after construction) must be addressed. This research topic, along with
the related topic of radon mitigation in existing schools, has been the subject of continuing EPA
radon mitigation research since 1988. The progress of this research has been presented at
previous ASHRAE IAQ conferences (1,2), in the ASHRAE Journal (3,4), and at a recent
symposium (5). A primary objective of this research is to develop written guidance on cost-
effective techniques for radon resistant and easy-to-mitigate school construction. This paper
summarizes preliminary results from an ongoing EPA study of current practices in radon
resistant new school construction including costs, techniques in current use, and advantages and
disadvantages of the different approaches.
Specific features in new school building design which have been installed or modified in
an effort to reduce radon levels vary considerably in complexity and cost. The minimum
features include sealing of major radon entry routes such as utility penetrations and expansion
joints, and providing a layer of coarse subslab aggregate so that an active subslab
depressunzation (ASD) system can be added if elevated radon levels are found in the building
after construction. Depending on the location, these minimum features generally add little to
school construction costs, yet make the success of a future radon control system more likely.
However, they generally provide only minimal radon mitigation in themselves, and retrofit radon
mitigation systems installation can be costly and more disruptive than including additional steps
during the construction phase.
An intermediate approach to installing radon resistant features involves providing a
subslab coarse aggregate layer and sealing major entry routes combined with a rough-in of radon
control system piping so that future costs and building disruption for aclivating a system (with
a fan) are minimized. A rough-in is thought generally to provide a higher level of performance
and lower costs and building disruption than a post-construction retrofit system could provide.
If all of the piping is completed without installing an exhaust fan, there is a possibility that the
system could provide some radon mitigation by passive venting of radon due to stack effect
pressures. However, passive subslab depressurization has not been researched extensively in
schools, because of all the competing pressures typically in these buildings.
Some schools have chosen to install fully active radon control systems which use fans to
depressurize the subslab aggregate and/or building HVAC fans to pressurize the building.
Several newly constructed slab-on-grade schools in the northeast U.S. that were built with active
or passive systems are being evaluated since they are thought to represent a range of current
practices in radon-resistant new school construction. The additional costs of installing radon-
resistant features have been tabulated for each of the schools. As the buildings are completed,
system effectiveness (including radon source strength, subslab pressure field extension, indoor
radon, and differential pressure induced by the HVAC system and ASD system) will be
measured in selected schools.
1

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ADDITIONAL COSTS FOR RADON RESISTANT FEATURES IN NEW SCHOOLS
In 1988 when school systems began asking for information on radon resistant new
construction and radon mitigation in existing buildings, little research data or radon mitigation
contractor experience were available. Since then, many existing schools with elevated radon
levels have been successfully mitigated, and a number of new schools (or additions) have been
built with radon resistant construction features. Most of this work has applied ASD, a technique
that has been successfully used for radon mitigation in thousands of houses across the country
over the past 5 years. Powered by a continuous exhaust fan, ASD operates by lowering the
pressure under the slab relative to inside the building, so that radon-containing soil gas cannot
enter the building through the many small openings generally found in the slab. Sealing methods
used alone have limited application and have not typically proven very effective in preventing
radon entry in schools or homes.
As part of this study, several radon mitigation contractors who had experience in
designing or installing ASD systems in new schools or school additions were contacted. Table
1 is a summary of these results for eight slab-on-grade schools or major additions where ASD
systems were installed during school construction. All these data were provided by the
contractors and/or architects involved with the building construction. The system designers and
installers are identified by the letters A through E. For one of the schools, the system was
installed by the plumbers on site. All of these ASD systems included extensive slab crack
sealing, stacks running from the subslab through the roof, and a network of subslab perforated
piping.
The radon mitigation contractors' system designs typically included an excess of radon
reduction capacity because contractors were working without written EPA guidance, and they
were concerned about liability for poor system performance. Design features included detailed
sealing of slab cracks/openings, extensive perforated piping under the slab, multiple stack pipes,
insulation of stack pipes, use of large diameter pipes, use of thick wall pipes, and trenching
around subslab perforated pipes to maximize flow. For some ASD installations where detailed
cost breakdowns were available, sealing costs represented 28 to 44% of the total installation
cost.
RECENT RELATED RADON RESEARCH IN SCHOOLS
Recent radon mitigation research in existing schools suggests that excellent radon
mitigation performance in new schools may be possible with simpler and less expensive ASD
designs than those presented in Table 1. A 1991 EPA Radon Symposium research paper on
radon resistant and easy-to-mitigate schools discussed the effects of suction pits and subslab
barriers on pressure field extension for ASD systems on large slabs (5). These results suggest
that, for excellent pressure field extension under large slabs, ASD subslab perforated piping
might not be necessary if there is a good subslab aggregate layer, a stack exhaust fan capable
of about 188 liters per second at 2.54 centimeters of water column pressure, and a large suction
pit in the aggregate surrounding the stack. An experimental single point ASD system with a
2

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suction pit in an area greater than 4650 square meters tested in the spring of 1991 showed
excellent depressurization of the entire area. Cost of this system, installed in a hospital building,
was about $1 per square meter. The system will be the subject of a detailed paper in the near
future. At the 1990 EPA radon symposium, successful radon mitigation was reported for an
existing 1,395 square meter school slab with good communication and one suction point (6).
In summary, research data in both existing and new schools suggest that simpler and
lower cost ASD designs can effectively mitigate much larger areas than the average of 492
square meters covered by the new school ASD designs presented in Table 1. This research
suggests that ASD systems may be much more tolerant of design or installation flaws than those
that many radon mitigation system designers for new schools are assuming. Future EPA radon
mitigation research will explore these ideas by testing the actual performance of some of the
existing school installations, as well as new designs.
SPECIFICATIONS FOR RADON RESISTANT NEW SCHOOL CONSTRUCTION
A number of features must be specified to ensure that radon resistant new school
construction is correctly designed and installed. Sealing of large openings in the slab such as
expansion joints and pipe penetrations were considered to be cost effective, but the cost
effectiveness is less for sealing smaller cracks. Since sealing was reported to represent as much
as 40% of the installation cost of current new school ASD radon systems, changes in sealing
specifications alone could have a significant cost impact.
Table 2 lists the construction details that radon contractors generally specified in their
designs for active or passive subslab depressurization systems that are installed during
construction of a new school. Their experience suggests that, unless these construction details
are clearly specified, they are quite likely to be misinterpreted. A discussion of these
construction details follows.
The designers generally specified 15 centimeter diameter stack pipes, although 20
centimeter pipe was occasionally used when several pipes were manifolded. Since the stacks are
under very small air pressure differentials, there is no pressure requirement for high strength
pipe, but schedule 40 is often used so that it will not be damaged on the construction site or by
occupants. Some architects changed the requirement to more expensive schedule 80 pipe. The
cost of piping and fittings escalates very quickly for larger pipe diameters and thicker walls
(schedule 40 versus schedule 80). For each building, all state and local codes should be
followed.
System designers generally agreed that they did not have confidence that aggregate alone
was enough to guarantee that each suction point would be effective in depressurizing larger areas
of the slab. Therefore, they typically ran perforated pipe under the slab to guarantee good
communication, and each suction point was then assumed to be capable of mitigating a few
hundred square meters of slab. Many slabs have subslab walls and footings that limit
communication, and typically require one ASD point for each area. The designers felt that a
3

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conservative estimate of the area that could be mitigated by one suction point in new school
construction was 500 to 2,000 square meters. Recent EPA research in an existing school has
shown that 1,395 square meters is possible (6), and recent research in new construction showed
that depressurization was possible under a greater than 4,650 square meter slab, perhaps greater
than 9,000 square meters if the building substructure is properly designed.
None of the designers used suction pits under the stacks as a simple method of improving
subslab communication. Perforated subslab pipe was considered as the best way to guarantee
subslab communication over a subslab area filled with aggregate. If perforated pipe is specified,
it can be much less expensive to use corrugated drainage pipe rather than rigid pipe. Not only
is corrugated pipe much less expensive, but on some job sites all rigid pipe must be installed by
plumbers while corrugated pipe can be installed by laborers. In any case, research has shown
(5) that excellent pressure field extension is possible if the aggregate layer is good, there are no
subslab barriers, and there is a large suction pit, even if no subslab piping is used.
It is possible that, if the HVAC system is operated to generate a negative pressure in
parts of the building (in a kitchen for example), the subslab negative pressure from the ASD
system may be overcome, and radon containing soil gas may enter the school. Most of the new
school ASD designers contacted for this study did not consider this to be a significant nsk
because their ASD systems were quite powerful and the slab sealing was thorough.
Roof detail refers to the way in which the ASD exhaust pipe is terminated outside the
building. Most designers include a ram cap on each stack, although they questioned whether
it reduced air flow and whether any rain protection was necessary in stacks which typically have
continual condensation (8). It is also very important to locate the ASD exhaust at least 9 meters
away from any outdoor air intakes so that it does not re-enter the building.
New school ASD designers generally specified a 150 to 250 watt exhaust fan for each
stack, capable of drawing 140 to 235 liters per second at 2.54 centimeters of water column
pressure. Although passive stacks were occasionally specified, the designers agreed that little
performance data are available for larger buildings, and most passive stack systems should be
considered rough-ins in case a radon problem is found in the future. In that case, a stack
exhaust fan would be added to comDlete the ASD system.
Although most school ASD designers specify extensive crack sealing, many of them
question whether all of the sealing is cost effective. They agree that if the cracks are large they
may disrupt the performance of the ASD system. It is considered necessary to seal large cracks
such as expansion joints and openings around plumbing; however, the benefits of sealing the
control joints in the slab or the floor/wall crack may not be worth the effort. There was general
agreement that the most durable and adhesive sealants are the urethane caulks.
Recent EPA research (5) has identified footing structures that have a significant impact
on the performance and cost of ASD systems. If this information can be provided to the
architect early enough, a footing structure might be selected that greatly simplifies ASD design
by minimizing the number of stacks needed.
4

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The ASD design should be detailed enough for the school architect to produce a drawing
showing the layout of all stacks, subslab pits, or perforated piping. These drawings should be
detailed enough to prevent improper installation during construction. The preferred design is
the one commonly used in large buildings such as supermarkets.
CONSIDERATIONS FOR HVAC PRESSURIZATION FOR RADON CONTROL
HVAC pressurization for radon control was attempted in one new school, although it met
with limited success because of operational problems. The major reason for the failure of the
system was that the energy management department was responsible for the HVAC system
operation, and their energy conservation objectives were in conflict with the radon control
objectives. Since the school was built with subslab aggregate, a single point ASD system was
installed in the one wing with elevated radon levels, and the radon concentration was
substantially reduced in the wing. Although it is very important for indoor air quality concerns,
experience in existing schools has implied that it may be difficult to permanently implement
positive pressunzation in many schools as an effective radon control technique since it can be
easily defeated. Table 3 lists some of the considerations for school HVAC pressurization that
may need to be considered.
Recent EPA research (2, 10, 11, 12) has shown thai HVAC systems generally have the
potential to provide radon mitigation, and further research is underway to investigate how to use
this potential most effectively. Although it is technically feasible to design and operate a school
to maintain a positive pressure to reduce radon entry, experience has shown that, in order to
reach the long-term national goal of indoor radon levels as low as outdoor radon levels (1988
Indoor Radon Abatement Act) in schools with a significant radon source strength, it is probably
necessary both to install an ASD system and operate the HVAC to pressurize the building.
CONCLUSIONS
Radon mitigation contractors in the northeastern U.S. are attempting to incorporate
conservative ASD radon mitigation systems in new school (and major addition) designs. In the
schools studied the additional costs ranged from about $3 to $11 per square meter of slab area.
Ongoing EPA radon mitigation research is substantiating equivalent radon mitigation
performance at reduced costs by developing specifications for radon resistant new school
construction that reduce the current emphasis on large numbers of ASD stacks, detailed crack
sealing, and extensive subslab piping. For example, a 4650 square meter slab in a hospital was
effectively depressunzed with only one suction point at an additional cost of about $1 per square
meter.
HVAC pressurization has the capability to provide both radon reduction and improved
indoor air quality in new and existing schools. However, it is inherently more complex than
ASD, and more subject to operational and maintenance problems since HVAC pressurization
systems depend on proper maintenance as well as a consistent control strategy which may be in
conflict with other objectives such as energy conservation. ASD systems have been very
5

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successful in reducing the entry of radon-containing soil gas and do not require significant
maintenance as they are generally independent of the operation of the other building systems.
Combining the two approaches is generally the most desirable approach both for radon reduction
and indoor air quality.
6

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REFERENCES
1.	Witter (Leovic), K.A., Craig, A.B., and Saum, D.W., New-Construction Techniques and
HVAC Overpressurization for Radon Reduction in Schools. In: Proceedings of ASHRAE
IAQ'88, Atlanta, 1988, EPA-600/D-88-073 (NTIS PB88-196159).
2.	Leovic, K.W., Craig, A.B. and Saum, D.W., The Influences of HVAC Design and
Operation on Radon Mitigation of Existing School Buildings, In: Proceeding of ASHRAE
IAQ'89, The Human Equation: Health and Comfort, San Diego, CA, 1989, EPA-600/D-89-015
(NTIS PB89-218762).
3.	Leovic, KW., Craig, A.B. and Saum, D.W., Radon Mitigation in Schools Part 1,
ASHRAE Journal, vol 32, No. 1, pp 40-45, 1990.
4.	Saum, D.W , Craig, A.B. and Leovic, K.W., Radon Mitigation in Schools: Part 2,
ASHRAE Journal, vol 32, No. 2, pp 20-25, 1990.
5.	Craig, A.B., Leovic, K.W., and Hams, D. B., Design of Radon Resistant and Easy-to-
Mitigate New School buildings, In Proceedings of The 1991 International Symposium on Radon
and Radon Reduction Technology, Philadelphia, PA, April 1991.
6.	Craig, A.B., Leovic, K.W., Harris, D. B., and Pyle, B.E., Radon Diagnostics and
Mitigation in Two Public Schools in Nashville, Tennessee, In Proceedings of The 1990
International Symposium on Radon and Radon Reduction Technology, Atlanta, GA, 1990.
7.	Gadsby, K.J., Reddy, T.A., Anderson, D F., Gafgen, R., and Craig, A. B., The Effect of
Subslab Aggregate Sire on Pressure Field Extension, In: Proceedings of the 1991 International
Symposium on Radon and Radon Reduction Technology, Philadelphia, PA, April 1991.
8.	Clarkin, M., Brennan, T., and Fazikas, D., A Laboratory Test of the Effects of Various
Rain Caps on Sub-slab Depressuriiation Systems, In: Proceedings of the 1991 International
Symposium on Radon and Radon Reduction Technology, Philadelphia, PA, April 1991.
9.	ASHRAE 1989. "Ventilation for acceptable indoor air quality." Standard 62-1989. Atlanta,
GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.
10.	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 of the 1991 International Symposium on Radon and Radon Reduction Technology,
Philadelphia, PA, April 1991.
7

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11. Fisher, G., Thompson, R.C., Brennan, T., and Turner W., Diagnostic Evaluations of
Twenty-Six U. S. Schools - EPA's School Evaluation Program, In: Proceedings of the 1991
Internationa] Symposium on Radon and Radon Reduction Technology, Philadelphia, PA, Apnl
1991.
12. Brennan, T., Fisher, G., Thompson, R. C., and Turner, W., Extended Heating, VentilaLing
and Air Conditioning Diagnostics in Schools in Maine, In: Proceedings of the 1991 International
Symposium on Radon and Radon Reduction Technology, Philadelphia, PA, April 1991.
ACKNOWLEDGEMENTS
The authors would like to express their appreciation for the information and assistance
provided by school personnel, architects, and contractors. Architects and radon mitigation
system designers who provided especially useful data for this study include Scott Spiezle of
Franklin B. Spiezle AIA Associates, PA, in Trenton, NJ; John Mallon of Radon Detection and
Control in South Heights, PA; Ronald Simon of R.F. Simon Company, Inc. in Bano, PA; and
Thomas Meehan of Saf-Air Radon Reduction, Inc in Orange, CT.
8

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Table 1. Summary of Additional Costs for Installing Radon Resistant Features
School location,
slab area,
square meters
System
designer,
installer
Date, new
school or
addition
Estimated,
cost, active
or passive
K of stacks,
average
slab area
per stack,
square
meters
Cost per
square
meter, per
stack
Pennsylvania,
3,515
designer A,
installer A
1990,
addition
$25,000,
active
6 stacks,
586
57.11,
$4,170
Pennsylvania,
4,233
designer A,
installer A
1991,
new
$13,000,
active
5 stacks,
847
$3.07,
$2,600
Pennsylvania,
2,911
designer B,
installer A
1990,
new
$21,000,
active
7 stacks,
416
$7.21,
$3,000
Connecticut,
3,069
designer C,
installer C
1990,
addition
$34,000,
active
8 stacks,
384
$11.08,
$4,250
New Jersey,
5,432
designer D,
plumbers
1991,
new
$25,000,
passive
11 stacks,
494
$4.60,
$2,270
Pennsylvania,
4,464
designer B,
installer B
1990,
new
$38,000,
passive
9 stacks,
496
$8.51,
$4,200
Pennsylvania,
4,650
designer B,
installer F
1990,
new
$46,500,
active
10 stacks,
465
$10.00,
$4,650
Pennsylvania,
3,720
designer E,
installer E
1991,
addition
$32,400,
active
15 stacks,
248
$8.71,
$2,160
AVERAGE:
(unweighted)
4,000


$29,362
8.9 stacks,
492
$7.34,
$3299
9

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Table 2. Construction Details in Specifications for New School ASD Systems
Constructs • detail
General considerations
Subslab aggregate
particle size, size distribution, depth of aggregate (5,7)
Stack type
diameter, wall thickness, sealing of joints
Number of stacks
area covered, effect of subslab barriers (footings and
walls)
Detail under slab
suction cavity under slab, perforated pipe extensions
HVAC system design and
operation
measures to avoid HVAC room depressurization
Detail on roof
rain cap, distance from fresh air intakes
Stack exhaust fan
passive stack, fan performance specification
Crack sealing
expansion joints, pour joints, control saw joints,
plumbing penetrations, floor/wall crack, sealants
Subslab footings & walls
impact on ASD, optimum layout for ASD (5)
Layout of ASD system
relative to footings, walls
10

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Table 3. Considerations for School HVAC Pressurization Radon Control
Considerations
Comments
Building airughiness
Tighter buildings are easier to pressurize.
Minimum fresh air supply rate
An outdoor air supply is generally required for
building pressurization.
More supply air than return air
in each room
A net positive air flow into rooms is required for
pressurization.
Night setback
If the HVAC is off at night, a building's substructure
is generally depressurized by stack effect. This allows
radon to build up all night. This may be acceptable if
the building is unoccupied at night, and the radon can
be diluted in the morning.
HVAC type
Some HVAC systems cannot produce positive
pressures (e.g., exhaust only system).
HVAC control philosophy
The HVAC control for energy conservation may be
different than optimum HVAC control for radon
mitigation and indoor air quality.
Ventilation standards
Building pressurization for radon control is consistent
wuh ASHRAE 62-1989 Ventilation Standards. (9)
1]

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AFPRJ-D «On TECHNICAL REPORT DATA
•tti_.I_in.J_, 1 O tu (I'tease read luiiruetiotis on the reverse before com/ilclu
i hlport no 2
EPA/600/D-91/207
3 f 1 JJi
4 title and subtitle
Cost and Effectiveness of Radon Resistant Features
in New School Buildings
& REPORT DATE
6 PERFORMING ORGANIZATION CODE
7 AUTHOR(S)
A.B.Craig (EPA), K.W. Leovic (EPA), and
D. W. Saum (Infiltec)
8 PERFORMING ORGANIZATION REPORT NO
9 performing organization name and address
Infiltec
Falls Church, Virginia 22041
10 PROGRAM ELEMENT NO
11 CONTRACT/GRANT NO
68-D0-0097, Task 2
(Sandy Cohen and Associates)
12 SPONSORING AGENCY NAME AND ADDRFSS
EPA, Office of Research and Development
Air and Energy Engineering Research Laboratory
Research Triangle Park, North Carolina 2771]
13 TYPE OF REPORT AND PERIOD COVERED
Published paper, 11/90 - 6/91
14 SPONSORING AGENCY CODE
EPA/600/13
is supplementary NOTES ^EERL project officer is Kelly W. Leovic, Mail Drop 54, 919/541-
7717. Presented at ASHRAE Conference, 1AQ91, Washington, DC, 9/2-5/91.
i6 abstract paper describes initial results of a study of several schools with radon
resistant features that were recently constructed in the northeastern U.S. These
designs generally are based on experience with radon mitigation in existing houses
and schools and radon-resistant new construction. The study was limited to slab-on-
grade schools where the most common radon resistant school design is active subslab
depressurization (ASD). The additional construction costs for eight schools built with
ASD ranged from $3 to Sll/sq m of slab area. The radon contractors who designed
these systems have tended to overdesign the radon reduction systems in the absence
of specific written guidance to follow to lessen potential liability in the event of sys-
tem failure. Design features include detailed sealing of all slab cracks, multiple ex-
haust stacks, and extensive subslab piping. Recent EPA research on radon mitigation
suggests that simpler ASD systems may provide sufficient radon resistance in new
buildings at lower costs. Components of a specification for radon resistant school con-
struction are discussed, based on comments from radon system designers. Another
school being studied was built with a heating, ventilation, and air-conditioning (HVAC^
pressunzation radon control system, and considerations for this type of system are
examined.
17 key WORDS AND DOCUMENT ANALYSIS
a DESCRIPTORS
b identifiers/open enoeo terms
c COSATl ("icld/Group
Pollution
Radon
School Buildings
Slabs
Design Criteria
Pollution Control
Stationary Sources
Subslab Depressurization
13B
07 B
13M, 051
13 C
14G
18 DISTRIBUTION STATEMENT
Release to Public
19 SECURITY CLASS {7hn Report)
Unclassified
21 NO OF PAGES
13
20 SECURITY CLASS (This pap*'!
Unclassified
77 PRICE
EPA form 22!0 1 19 73)

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