Protection against lightning – Part 2: Risk management
IEC 62305-2:2010 is applicable to risk assessment for a structure due to lightning flashes to earth. Its purpose is to provide a procedure for the evaluation of such a risk. Once an upper tolerable limit for the risk has been selected, this procedure allows the selection of appropriate protection measures to be adopted to reduce the risk to or below the tolerable limit. This second edition cancels and replaces the first edition, published in 2006, and constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: 1) Risk assessment for services connected to structures is excluded from the scope. 2) Injuries of living beings caused by electric shock inside the structure are considered. 3) Tolerable risk of loss of cultural heritage is lowered from 10-3 to 10-4. The value of tolerable risk of loss of economic value (RT = 10-3) is introduced, to be used when data for cost/benefit analysis are not available. 4) Extended damage to surroundings structures or to the environment is considered. 5) Improved equations are provided for evaluation of - collection areas relevant to flashes nearby a structure, - collection areas relevant to flashes to and nearby a line, - probabilities that a flash can cause damage, - loss factors even in structures with risk of explosion, - risk relevant to a zone of a structure, - cost of loss. 6) Tables are provided to select the relative amount of loss in all cases. 7) Impulse withstand voltage level of equipments was extended down to 1 kV. This bilingual version corresponds to the monolingual English version, published in 2010-12.