Assessing the dangers of lightning to livestock, a case study of a lightning event resulting in the deaths of 22 cattle

The majority of lightning fatalities occur in outdoor environments. The application of the IEC62305-2 lightning risk standard provides little insight into the risks to living beings in open spaces. The Median Lethal Limit (MLL) provides a means of describing the dangers to living beings in open spaces. A site in Mpumalanga, South Africa was investigated after a lightning incident resulted in the deaths of 22 cattle. The IEC62305-2 methodologies are used to assess the enclosure that housed the cattle. The same area is then assessed using the MLL and the results are compared. It is found that the MLL method in conjunction with the application of the rolling sphere provides a reasonable approximation for the danger of lightning to living beings in the enclosure. It is advised that some form of protection measures be installed to protect the cattle in the enclosure during a thunderstorm.