Relation Between The Material of Roof and The Risk of Lightning Caused Damage

To determine the expected number of accidents caused by a lightning strike has different methods (most popular is PMAS, EGM or SLIM). The aim of the paper to present the case of the further-delvelope of PMAS method throw interesting special case.For an air-termination system it is necessary to know the number of the possible lightning strikes for a given area in a given year to design it well. If the methods, which serve that purpose to determinate the risk level, use too much simplification or will be inadequately neglected that could be cause incorrect risk determination.The aim of this paper is to show one possible case when this could happen.