Which statement about yellow CAUTION RF signs is true?

• A. You are entering an area with RF levels up to the MPE limits and training is required.
• B. RF levels exceed MPE limits and no protective measures are needed.
• C. No RF hazards exist.
• D. Only mechanical hazards are present.

Answer: (A)

Yellow CAUTION RF signs signal that there is potential exposure to radiofrequency energy in the area. They indicate that the RF levels are present at or near the maximum permissible exposure (MPE) limit, which means entry requires awareness and appropriate training before working there. If RF levels actually exceeded the MPE, protective controls or restricted access would be required rather than simply a caution sign. The absence of hazards would not be indicated by a CAUTION RF sign, and that sign does not point to only mechanical hazards. So the correct interpretation is that you are entering an area with RF levels up to the MPE and you must have the proper training.