Radar radiation hazards and precautions

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Radar is an essential tool in collision avoidance and there is very little risk to pilots and deckhands from RF exposure. However there is an obligation here on the part of the ship operator which is supported by information provided by the radar manufacturer.

Fundamentally, marine radar emits non-ionising microwave radiation which does not pose a carcinogenic risk to humans (unlike x-rays and other types of higher frequency ionising radiation). However with all types of microwave radiation there is some risk of surface heating of human skin and eyes associated with prolonged contact.

Permitted RF exposure for workers and bystanders is set by national safety regulations which differ in their specifics. Exposure limits are based on length of exposure, frequency, source characteristic and thermal heating effect. Manufacturers support operational safety by publishing information on power levels and proximity in the ship’s manual provided for each radar. That is required by technical standard IEC 62388, but the same information seems commonly provided for non-SOLAS radars as well. The RF level which pilots or other deckhands etc. receive from radar scanners is very low compared with those described in the radar manuals.

While pulsed magnetron radars may have high peak power, the narrow pulses required to meet range resolution requirements result in duty cycles that are very low, so average power is low. Solid state radars (i.e. the newer type) typically process the signal differently, using transmit waveforms with lower peak power but higher duty cycle.

In order to obtain a clear 360-degree view and long range detection, radars are normally installed high on or above the ship’s superstructure which puts them at a distance from most people. Radar signals are also pulsed (i.e. non-continuous) and emitted from a rotating scanner. All of these aspects serve to reduce the likelihood of over exposure to bystanders.

In the experience of CIRM radar manufacturers, “to get close enough to reach occupational exposure limits, you would be in danger of getting whacked in the head by the turning antenna”.