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The U.S. Nuclear Regulatory Commission is in the process of rescinding or revising guidance and policies posted on this webpage in accordance with Executive Order 14151 Ending Radical and Wasteful Government DEI Programs and Preferencing, and Executive Order 14168 Defending Women From Gender Ideology Extremism and Restoring Biological Truth to the Federal Government. In the interim, any previously issued diversity, equity, inclusion, or gender-related guidance on this webpage should be considered rescinded that is inconsistent with these Executive Orders.

Home About NRC Radiation Protection How the NRC Protects You Health Physics Positions Based on 10 CFR Part 20

Health Physics Questions and Answers - Question 27

Question 27: Do licensees have to post controlled areas (outside the restricted area) as airborne radioactivity areas if derived air concentrations (DAC) are exceeded?

Answer: Yes, if the airborne radioactivity is indoors. If the airborne radioactivity is outdoors, the answer depends on the particular situation. In certain situations the licensee may need to identify and delineate an outdoor airborne radioactivity area. For example posting would be required in a small area, accessible to workers, in the immediate vicinity of a vent on the outside of a building, exhausting air containing concentrations of radioactive materials in excess of the DACs specified in Appendix B to 10 CFR Part 20.

(References: 10 CFR 20.1003, 10 CFR 20.1902)

Page Last Reviewed/Updated Friday, November 24, 2017