ETL 1110-3-438
15 SEP 93
INDOOR RADON PREVENTION AND MITIGATION
1. PURPOSE: This letter establishes design criteria for all U.S.
Army facilities to eliminate health risks due to indoor radon.
2. SCOPE: The design standards established herein are applicable to
all newly constructed and substantially altered Army facilities both
inside and outside the Continental United States.
3.
REFERENCES:
a. DA Publication.
AR 200-1, Chapter 11, Army Radon Reduction Program.
b. U.S. Environmental Protection Agency (EPA) Publications.
(1)
EPA 520/11-87-20,
Radon Reference Manual.
(2)
EPA 600/8-88-087,
Radon-Resistant Residential New
Construction.
(3)
EPA 625/5-87/019,
Radon Reduction Techniques for Detached
Houses.
(4)
EPA 625/5-88/024,
Application of Radon Reduction Methods.
(Most of the research work and publications by EPA have
concentrated on single family, detached dwellings. Military
facilities are generally larger and of different construction
methods than single family residences. The design criteria and
details contained in this document are selectively adapted from
the EPA data and recommendations.)
4. PROPERTIES OF RADON: Radon is a naturally occurring, chemically
inert and water soluble radioactive gas that is undetectable by human
senses. It is formed by the radioactive decay of thorium and uranium.
These source elements are found in low, but varying; concentrations in
soils and rocks. Radon, being a gas, escapes from the ground
following paths of least resistance such as through small fissures,
gravel, sand, and other porous soils. Normal subsoil investigations
do not locate these radon paths with sufficient detail and accuracy to
reliably predict points where radon emerges from the earth or probable
levels of concentration. Radon-220, derived from thorium, has a half-
life of 55 seconds giving it limited time to enter buildings before it
decays to a nongaseous element. Radon-222, derived from uranium and
having a halflife of 3.8 days, is the primary source of indoor radon.
Refer to EPA 520/1-87-20, Radon Reference Manual for more detailed
information.
5. OTHER RISKS: Health risks associated with radon are from its
decay products, not the radon gas. Radon-222 decays in several
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