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Page Title:
Appendix A: Review of Measurements of Equilibrium Factors |
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|  DOE-STD-1121-98
APPENDIX A. REVIEW OF MEASUREMENTS OF EQUILIBRIUM FACTORS FOR
RADON AND THORON PROGENY
Values of radon progeny equilibrium factors have been published in the literature. Equilibrium
factors depend on many variables, including whether measurements are made indoors or outdoors,
whether there is smoke and dust in the air, the proximity of the radon source, and the rate of air exchange
or wind speed.
A.1 MEASUREMENTS OF RADON PROGENY EQUILIBRIUM FACTORS
Fifteen results of outdoor FRn studies and three recommended values are summarized in Table XIV.
Observed values range from 0.01 to 1.00, with an average value of 0.39 and average ranges from 0.16 to
0.73. Since these measurements were made under very different circumstances, the wide range of values
is not surprising. These results show that local characterization of FRn is advisable. Recommended values
of 0.7 or 0.8 are higher than have been observed at the Uranium Mill Tailings Remedial Action
(UMTRA) Project (Reif and Andrews 1992) and recently in the southeastern and southwestern USA in
240 measurements at 16 sites (Wasiolek and James 1995) and at the Fernald Environmental Management
Project (FEMP) under several stability classes (Medora 1996).
Table XIV. Radon Equilibrium Factors Measured Outdoors
Range
Country
avg
sd
min max Reference
Environment
Rec.
USA
0.87
Cox et al. (1970)
USA
0.79
0.57 0.89 George and Breslin (1980)
USA
0.1
0
1 Reif and Andrews (1992)
at the source
0.1
USA
0.45
0.1
1 Reif and Andrews (1992)
upwind
0.4
USA
0.2
0 0.91 Reif and Andrews (1992)
downwind
0.2
USA
0.1
0 0.17 Borak (1983)
USA
0.26
Schultz et al. (1994)
USA
0.63
0.38 0.95 Wasiolek and James (1995)
varied
USA
0.23 0.12
0.1 0.45 Medora (1996)
stabil. class A
USA
0.22
Medora (1996)
stabil. class B
USA
0.39 0.2
0.22 0.63 Medora (1996)
stabil. class D
USA
0.22
0
0.17 0.25 Medora (1996)
stabil. class E
Yugoslavia
0.25
Planinic and Faj (1990)
West Germany
0.71
Jacobi (1972)
West Germany
0.43
0
1 Keller and Folkerts (1984)
0.16 0.73 All Studies
AVERAGE
0.39
Std. Dev.
0.25
0.18 0.33
Min of Minima
0
Max of Maxima
1
No. Studies
15
recommendation
UNSCEAR (1988) annex A para 93
0.8
recommendation
UNSCEAR (1993) annex A Table 24
0.8
recommendation
NCRP (1987)
0.7
127
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