Lightning Protection Risk Assessment (Lightning Protection Level, LPL)

A systematic, quantitative procedure under NEN-EN-IEC 62305-2 to determine whether a structure requires lightning protection and, if so, which protection level (Lightning Protection Level, LPL I to IV) is required for it. The analysis calculates the annual risk of four types of loss — loss of human life, loss of public service, loss of cultural heritage, and economic loss — as a function of factors such as the location and dimensions of the building, the regional lightning flash density, the presence of surrounding structures or trees, the construction material used, the presence of flammable or explosive substances, and the extent to which people are present in or near the building. This calculated risk is then compared with a tolerable risk level laid down in the standard; if the calculated risk stays below that level, additional lightning protection is not mandatory, but if it exceeds that level, a lightning protection system (LPS) of the corresponding protection level must be designed — where LPL I represents the strictest class and LPL IV the least strict. This risk assessment is therefore the decisive design document that precedes the actual technical implementation of the lightning protection system (LPS) itself.