Also known as: RA#, RA...
RA has various meanings in the Caution category. Discover the full forms, definitions, and usage contexts of RA in Caution.
Any part of an installation accessible to employees in which there exists a radiation level of 7.5 millirem in any one hour over 150 millirem in any seven consecutive days. Any area with radiation levels greater than 5 millirems (0.05 millisievert) in one hour at 30 centimeters from the source or from any surface through which the radiation penetrates.
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