1 November 1996
alpha particles that damage lung tissue and leads to lung cancer. EPA recommends the removal of radon
gas rather than removal of decay products with high efficiency air filters or air cleaning devices. For more
information on the disadvantages of air cleaning as the primary method for radon control, refer to EPA
625/5-87/019. (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.)
6. PRIORITY OF FACILITY TYPES. Priorities for designing various types of military facilities to reduce
indoor radon are based upon the USACE Radon Program.
a. Priority 1: Day care centers, hospitals, schools, living quarters including barracks, unaccompanied
personnel housing (officers and enlisted) and family housing, and routinely occupied spaces below grade.,
Priority 2: Offices, work areas, and other facilities having 24-hour operations.
c. Priority 3: All other routinely occupied structures including morale, welfare and recreational
d. Priority 4: All intermittently occupied structures that are used by any military or civilian employee
whose total work time in those buildings equals or exceeds 80 hours per year.
e. Structures occupied less than 80 hours per year by any employee do not require radon preventive
7. INDOOR RADON CONCENTRATION AND ACTION LEVELS. Radon is measured in picocurries per
liter (pCi/lL or Becquerel per cubic meter (Bq/m 3) of air. EPA studies have assigned relative health risks for
various concentration levels of indoor radon based upon periods of exposure; concentration levels below 4
pCi/L (148 Bq/m 3) are negligible.
The action levels given below conform to the USACE Radon Program:
a. Negligible: 0 to 4 pCi/L (0 to 148 Bq/m 3).
b. low: 4 to 8 pCi/L (148 to 296 Bq/m 3).
c. Moderate: 8 to 20 pCi/lL (296 to 740 Bq/m 3).
d. High: 20 to 200 pCi/lL (740 to 7400 Bq/m 3).
e. Very High: Greater than 200 pCi/lL (7400 Bq/m 3).
8. DETERMINATION OF RADON POTENT. EPA 402-R-93-078 establishes a program for measuring
indoor radon in existing buildings. Radon measurements data should be added to the real property
database. Where installations maintain accurate records of radon measurements for existing buildings on
army installations, these pre-mitigation measurements may be used as the basis for determining potential
radon levels for new facilities. Design criteria will be based upon the highest radon measurements in
existing buildings in close proximity to the new facility. Where the new facility is in a remote location, the
highest measurements on the installation will determine the design criteria. In cases where existing radon
data are not available, soil-based radon and radium measurement may provide useful information in
evaluating radon potentials. Procedures for using soil gas measurements to estimate radon potentials are
still evolving, contact EPA for the most up-to-date guidance. Indoor radon monitors are available that will
measure radon levels automatically and continuously showing current and long term measurements as