Lightning protection levels I to IV are laid down to define light­ning as a source of interference. Each lightning protection level requires a set of

  • Maximum values (dimensioning criteria which are used to design lightning protection components in such a way that they meet the requirements expected) and
  • Minimum values (interception criteria which are necessary to be able to determine the areas which are sufficiently protected against direct lightning strikes (rolling sphere radius)).
Lightning protection level Maximum values (dimensioning criteria)
Maximum peak value of the lightning current Probability that the actual lightning current is smaller than the maximum peak value of the lightning current
I 200 kA 99 %
II 150 kA 98 %
III 100 kA 95 %
IV 100 kA 95 %
Table 2.7.1 Maximum lightning current parameter values and their probabilities
Lightning protection level Minimum values (dimensioning criteria)
Minimum peak value of the lightning current Probability that the actual lightning current is greater than the minimum peak value of the lightning current Rolling sphere radius
I 3 kA 99 % 20 m
II 5 kA 97 % 30 m
III 10 kA 91% 45 m
IV 16 kA 84 % 60 m
Table 2.7.2 Minimum lightning current parameter values and their probabilities
 
Tables 2.7.1 and 2.7.2 show the assignment of the lightning protection levels to the maximum and minimum values of the lightning current parameters.