Recently updated HSE guidance looks at the risks posed by radio frequency antennas, the hazardous areas around them, and the need for precautions such as surge protection to ensure there is no risk of them igniting an explosion.

The HSE admits that this is a small risk, but adds that some observers have reported ‘electrical discharges’ witnessed on structures located close to radio broadcast transmitters.

“Ignition-capable sparks can occur when electric currents and voltages are induced in conducting structures by electromagnetic waves produced by radio-frequency (RF) transmitters (e.g. radio, television and radar),” the guidance explains.

Operators of onshore major hazard installations are told that they must identify nearby transmitters, including their frequency and power where such information is available to the public.

The range of the hazardous area is potentially quite large – incorporating transmitters up to 17.9km away from a gas group IIA location, 21.2km from gas group IIB and 29.2km from gas group IIC.

In the last of those cases, that’s a circle with an area of over 2,600 square kilometres, and while the risk of ignition may be small, it highlights the importance of methods such as surge protection to help eliminate the possibility of an explosion occurring in this way.