How many DAC-hours equal to 2.5 millirem?

To determine how many DAC-hours correspond to 2.5 millirem, it's crucial to understand the relationship between DAC (Derived Air Concentration) and the dose received in rem or millirem. A DAC is a measure used in radiation protection to estimate the concentration of radioactive material in air which, if inhaled for a specific duration, leads to a defined radiation dose.

A DAC-hour represents the accumulation of exposure over time, which is linked to the inhalation of radioactive material at a level above a certain threshold. The regulatory frameworks often denote that one DAC-hour corresponds to a known conversion factor for exposure in terms of millirem.

Specifically, it's established that 1 DAC-hour results in a dose of 300 millirem for most radionuclides. Therefore, to find out how many DAC-hours correspond to a dose of 2.5 millirem, one can use the following relationship:

• ( \text{DAC-hours} = \frac{\text{Dose in millirem}}{300 \text{ millirem}} )

Applying this to 2.5 millirem gives:

• ( \text{DAC-hours} = \frac{2.5}{300} \approx 0.0083 )

However,