Analysis of Lightning Hazards in the Context of Formal and Technical Requirements for Facilities with Designated Explosion Hazard Zones

Aim: Reducing the number of fires in buildings with designated explosion hazard zones, which are initiated by lightning discharges despite the application of lightning protection standards. Introduction: Buildings with explosion hazard zones are commonly protected against the effects of lightning discharges to the ground. Analysing statistical data, it can be seen that in the years 1951–2003 there were 480 fires in tanks with flammable substances. In 149 cases, “lightning” was indicated as the source of ignition, which is 31.1%. Lightning discharge is the most important and significant factor causing fires. Methodology: An analysis of the applicable regulations in the field of lightning protection was carried out, taking into account the specificity of explosion hazard zones. An analysis of the case of a fire caused by a lightning discharge in Poland was carried out. The analysis was supplemented with tests of lightning protection connections with a surge current characteristic of a lightning discharge to the ground. Conclusions: During the conducted tests, two test results were observed. In the first, the tested object withstood a series of three impulse currents in accordance with the H classification of the EN 62561-1 standard and was not subject to mechanical damage. In the second, mechanical deformations of the tested samples were observed, which resulted in a negative result in light of the H classification of the above standard. During all the conducted tests , significant sparking was observed on all bolted joints. It is significant that the samples of joints meeting the H classification spark. Based on the observations, it was determined that the sparking was within a radius of up to 2 meters from the bolted joint. Only in the case of elements made of pure copper, sparking of the connection point was observed at a distance of less than 1 meter. The test results clearly indicate that running and connecting lightning current discharge wires through an explosion hazard zone may result in ignition of an explosive atmosphere if it is created there. In real conditions, it is very difficult to make the necessary modifications to the existing infrastructure that could counteract the described phenomena. The only effective method that could reduce the risk of fire is the use of an insulated external LPS (lightning protection system). In practice, such action will be accepted from an economic point of view only in the event of lightning losses that exceed the costs of potential investments to reduce the risk.