Final answer:
The safe distance for photographic equipment during refueling operations should be significant to prevent risks of ignition, with exact distances depending on the equipment and site regulations. Consulting operating personnel for a safe perimeter is advisable, referencing safety distances from similar contexts.
Step-by-step explanation:
The safe distance for photographic equipment during refuel/defuel operations is not explicitly stated in the information provided, but by considering the principles of safety related to distance and machinery, we can infer some guidelines.
If we take cues from the given information on the maximum safe intensity of microwaves for human exposure and apply similar principles of safety and distance from hazardous sources, it is reasonable to suggest maintaining a substantial distance from refueling operations to minimize the risk of ignition from electrical components of photographic equipment.
The exact safe distance may vary based on the specifications of the equipment and the regulations of the facility.
Based on safety distances mentioned for other applications like the effective air defense perimeter or the illumination drop-off for camera flashes, and the FAA regulations on flight paths, one can deduce applying similar precautionary principles is wise.
A safe practice would be to consult with the operating personnel at the site to determine a safe perimeter, which may be significantly beyond the distance at which a camera flash is effective (10-15 feet) and within which radar exposure is considered safe.