Taken from BS 6651:1999:
"Lightning is a natural hazard, being the discharge of static electricity generated in parts, called “cells”, of storm clouds. In the UK, about one million flashes strike the ground each decade. Some lightning flashes damage buildings and a few kill or injure people and animals, either directly or indirectly, by causing fire and explosions. Statistics for deaths by lightning show the risk to be very low, being one in two million per annum.
"The BS EN 62305 series outlines the general technical aspects of lightning, illustrating its principal electrical, thermal and mechanical effects. Guidance is given on how to assess the risk of being struck and how to compile an index figure as an aid to deciding whether a particular structure is in need of protection. The guidance given is of a general nature and its application to specific lightning protection installations has to take into account the particular conditions pertaining to those installations. In cases of difficulty, specialist advice should be sought.
"It is emphasized that even where protection is provided it can never be completely effective in eliminating the risk of damage to the structure."
More information on Parts 1-4 is available via the following links:
