Alert

Due to a lapse in appropriations, the NRC has ceased normal operations. However, excepted and exempted activities necessary to maintain critical health and safety functions—as well as essential progress on designated critical activities, including those specified in Executive Order 14300—will continue, consistent with the OMB-Approved NRC Lapse Plan.

Derived air concentration (DAC)

The concentration of a given radionuclide in air which, if breathed by the reference man for a working year of 2,000 hours under conditions of light work (with an inhalation rate of 1.2 cubic meters of air per hour), results in an intake of one annual limit on intake (ALI). Established DAC values are given in Table 1, Column 3, of Appendix B to Title 10, Part 20, of the Code of Federal Regulations (10 CFR Part 20), "Standards for Protection Against Radiation."

Page Last Reviewed/Updated Tuesday, March 09, 2021