United States
                Environmental Protection
                Aaencv	
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 27711
                Research and Development
EPA/600/S8-90/062 Sept.  1990
EPA       Project  Summary
                Interim  Radon-Resistant
                Construction Guidelines  for  Use
                in  Florida-1989
                Thomas D. Pugh
                  This project was initiated with the ob-
                jective of investigating, analyzing, and
                developing radon-resistant construction
                guidelines which are consistent with
                other building codes and which could be
                applied to Florida.
                  A literature search was conducted in
                which available information was obtained
                on radon remediation techniques, new
                construction methods,  and existing
                codes  (e.g., those in  Sweden and
                Canada) for  radon-resistant buildings.
                Techniques identified by the research
                were  amended,  modified,  or supple-
                mented  for  incorporation into draft
                model guidelines for new construction
                in format consistent with the Standard
                Building Code  promulgated by the
                Southern Building  Code Congress In-
                ternational, Inc.
                  A technical review advisory commit-
                tee which included building'contractors,
                architects, engineers and representa-
                tives of federal, state and local govern-
                ments was formed  during the develop-
                ment  of the guidelines. The committee
                provided input and  recommended
                changes to the draft guidelines.
                  Although this project has resulted in
                guidelines for recommended construc-
                tion practices, it should be coupled with
                a carefully planned and implemented
                program of experimentation. Eventually
                this approach will lead to building code
                provisions which are scientifically de-
                fensible, cost effective, reliable,  and
                easily incorporated into standard con-
                struction practice.
                  This Project Summary was developed
                by EPA's Air and Energy Engineering
 Research Laboratory, Research Triangle
 Park, NC, to announce key findings of
 the research project that is fully docu-
 mented in a separate report of the same
 title ( See project report ordering infor-
 mation at back).

 Introduction
   Over the past decade there'has been
 growing concern about health effects asso-
 ciated with exposure to radon and its prog--'
 eny. Florida is the first state in the nation to
 establish standards which set limits on ra-
 don progeny in  buildings. Many currently
 available publications address  mitigation
 techniques;  However, few  studies docu-
 ment radon-resistant methods for new con-
 struction, and mitigation techniques may
 not be the most appropriate ones for* new
 construction. In  addition, many factors in
 the southeastern U. S.  make existing re-
 search conducted in the northeast difficult
 to apply here. These  factors include geol-
 ogy, climate, common building  practices,
 and lifestyles.
   The approach to identifying ideal radon-
 resistant features is two-fold: (1) it is neces-
 sary to determine the  likely entry routes for
 radon into the building,  and (2) standard
 building practices and details that appear
 responsible for allowing radon into a struc-
 ture should be examined to determine how
 they could be modified to create a radon
 barrier. These possible modifications  re-
 quire much more investigation.
   The problem of elevated radon concen-
 trations in homes can be approached from
 two directions: by filtering out or'diluting the
 radon and its progeny once they are inside
 the dwelling, or by preventing the radon-

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carrying soil gas from entering the home.
  Radon filtration/dilution  is a less than
perfect solution  because: (1) it has a rather
high initial cost, (2) as an active system it will
require maintenance, (3)  it is susceptible to
owner interference, (4) it requires energy to
operate, and (5) it has a negative impact on
other energy conservation measures.
  Systems that prevent soil gas from enter-
ing abuiiding may be further subdivided into
two classes:  those which  are totally pas-
sive, and active systems, those which require
continuous energy inputs.
  Active systems, perhaps the mosttested
and documented, can be further divided
into those drawing soil gas from beneath
the slab of a building and venting it to the
outdoors where it is quickly diluted to safe
concentrations,  and those that attempt lo_
reduce the emergence of soil gas by con-
tinually pumping a small volume of air be-
neath the slab.  Both systems have some
negative characteristics.
  A thorough study of the literature, fol-
lowed by detailed experimentation of the
more promising methods for use in Florida,
should lead to the establishment of firm
protocols  for radon-resistant  new  home
construction. The guidelines developed in
this report are based on the best information
obtained to date.

 Procedures
  Aliterature search wasconducted in which
information was obtained on radon  reme-
diation techniques, new construction
methods, and codes (e.g., those in Sweden
and Canada) for radon-resistant buildings.
The Swedish codes had to be translated
into Englishbefore they could be analyzed.
The effectiveness of each technique was
evaluated, and those techniques with spe-
cific application to southern  construction
were noted.
  AlechnjcaJj«yJgwTiadvisory _CQmmjttee__
which included building contractors,  archi-"
tects,  engineers,  and representatives of
federal, state, and local  governments was
formed during the  development phase of
the guidelines. The committee provided in-
put and recommended changes to the draft
guidelines.
 Results/Discussion
  The full report contains 11 sections: (1)
General, (2) Isolation membranes, (3) Con-
crete slabs in isolation systems, (4) Crawl
space construction, (5)  Slab below grade
and basement construction, (6) Combined
construction  types, (7) Soil gas ventilation
systems, (8) Other entry pathways for ra-
don, (9) Space conditioning systems, (10)
approved materials,  caulks, and sealants,
and (11) Illustrated details.
  Construction  details  and practices are
divided into:  (1) those that  are most confi-
dently recommended, (2) those which are
recommended,  but with less confidence,
and (3) those which are recommended, but
with least confidence.

 Conclusions
   Institution of these interim guidelines
should be accompanied by the knowledge
that further experimentation and additions
to the literature may require revisions from
time to time.
 T.D. Pugh Is with Florida A and M University, School of Architecture, Tallahassee, FL
 32307
 David C. Sanchez is the EPA Project Officer (see below).
 The complete report, entitled "Interim Radon-Resistant Construction Guidelines for Use in
 Florida --1989," (Order no. PB90-265 349AS; Cost: $15.00 cost subject to change)  will be
 available only from:
         National Technical Information Service
         5285 Port Royal Road
         Springfield, VA 22161
         Telephone: 703-487-4650
 The EPA Project Officer can be contacted at:
         Air and Energy Engineering Research Laboratory
         U.S. Environmental Protection Agency
         Research Triangle Park, NC 27711
 United States
 Environmental Protection
 Agency
 Center for Environmental
 Research Information
 Cincinnati, OH 45268
 Official Business
 Penalty for Private Use $300
 EPA/600/S8-90-062

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