This value of m has been accepted as a compromised solution for risk assessment in the standards [2]. From Figure 8.3 it is clear that this value is too small for lower structures and too great for higher ones. This means that for structures lower than 20 m the number of strikes may be underestimated and for structures greater than 20 m the factor m 1⁄4 3 leads to a certain margin of safety; when the structure height increases from 60 to