What is the maximum permissible external surface dose rate for the package?

• A. 0.05 mrem/h
• B. 0.5 rem/h
• C. 0.5 mrem/h
• D. 5 mrem/h

Answer: (D)

Radiation safety for packaging relies on limiting the amount of radiation that can be detected at the surface to protect people handling the package. The external surface dose rate is the rate at which radiation would be received if a dosimeter were placed directly on the package surface.

Five millirem per hour is the standard limit used for many transport packaging scenarios. In more common units, that’s about 0.05 millisievert per hour. This relatively low, conservative limit helps ensure that workers who handle or inspect the package over a typical shift would stay within annual occupational exposure guidelines, even with repeated or close-range exposure.

Other options imply either much higher or much lower rates than those typically permitted. For example, five millisieverts per hour would be a much larger rate than allowed at the surface, while rates far below five millirem per hour would be unnecessarily restrictive given practical transport conditions.