Air Monitoring - std-1121-98-reaffirmation0061

DOE-STD-1121-98

Appendix A contains a review of measurements of radon progeny equilibrium factors on which

Table III is based. Appendix A also contains a brief review of published values of thoron progeny

4.5.3 Performance Criteria for Instruments Used at Doe Sites to Characterize Airborne

Radon and Thoron and Their Progeny

The American National Standards Institute provides performance specifications for instruments for

the measurement of radon, radon progeny, and thoron progeny in air (ANSI 1994a, 1994b). All

instruments should be operated using standardized approved operating procedures. All operators should

be trained on these procedures prior to performing field measurements.

4.5.3.1 Air Monitoring

Instruments used for air monitoring should have the following characteristics:

a response rate that is limited only by radon progeny ingrowth (i.e., a full-scale response time of

about 4 hours; does not apply to thoron),

a sensitivity to environmental influences that complies with the applicable parts of ANSI N42.17A-

1994 and ANSI N42.17B-1989,

a coefficient of variation of no more than 15% when making one-hour measurements of constant,

normal background concentrations, and

a calibration bias of no more than 10%.

Enclosing the instrument in a protective housing may be necessary to limit environmental influences.

4.5.3.2 Air Sampling

Instruments used for air sampling should have the following characteristics:

a sensitivity to environmental influences that complies with the applicable parts of ANSI N42.17A-

1994 and ANSI N42.17B-1989,

a coefficient of variation of no more than 15% when making 170-hour measurements of constant,

normal background concentrations, and

a calibration bias of no more than 10%.

4.5.4 Participation by DOE Sites in an Intercomparison Program for Radon Instrument

Calibration, Precision, and Accuracy

Compliance of the measuring system(s) with the above performance specifications should be

demonstrated by subjecting a representative sample of instruments to periodic (annual if possible) radon

and/or radon progeny comparison exercises, if and when such exercises are conducted by Department of

Energy laboratories. If and when the DOE Laboratory Accreditation Program (DOELAP) offers a radon

measurements program, DOE sites should participate in the DOELAP.

4.5.5 Calibration and Quality Control for Radon, Thoron, and Progeny Instrumentation

All instruments should be recalibrated at least annually. The lack of stability of some instruments

may require that they be calibrated more frequently. Calibrations should be performed in a controlled

atmosphere which is monitored with instruments whose flow rate and detection efficiency have been