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case of lightning effects, must be assessed. To this end, the If the structure is divided into several zones, the relevant val-
values of risk R 4 , which are determined according to section ues c a , c b , c c and c s can be subdivided according to the share
3.2.5, are required. For this purpose, the values of the structure of the volume of the relevant zone in the total volume (in case
c b , of the content c c , of the internal systems (including their of non-industrial structures) or the share of the jobs in the rel-
failure) c s and of animals c a , if any, must be known and divided evant zone in the total number of jobs (in case of industrial
in zones. These values are typically provided by the planner of structures).
the protection measures and / or by the owner of the structure. Thus, the simplified procedure according to EN 62305-2 fol-
In many cases, these values are not available or it is difficult to lows the only reasonable procedure for examining the profit-
obtain these values (e.g. the owner does not want to provide ability of protection measures, namely a comparison based on
these values). In case of industrial structures or administra- exclusively economic data. Only the total value of the structure
tion buildings with sensitive production or work processes, (c t ) and the values c a , c b , c c , c s are determined according to a
the transparency required for the reasonable implementation simplified method. However, if exact data is available for the
of the risk management stands in contrast to the necessity of stated values, these values should be used.
confidentiality of sensitive economic data. In other cases, the In addition to type of loss L4, one or more other types of loss
acquisition of these data is too complex. L1 to L3 are typically relevant to a structure. In these cases,
EN 62305-2 includes a simplified procedure to implement the the procedure described in 3.2.8 must be used first, in other
risk management for the type of loss L4 in cases where it is dif- words it must be examined whether protection measures are
ficult to assess possible damage sums resulting from lightning required and the risk R must be smaller than the tolerable risk
effects. R T for the types of loss L1 to L3. If this is the case, the prof-
The total value c t of the structure is determined according to itability of the planned protection measures is examined ac-
Table 3.2.9.1 based on the volume of the structure (in case cording to Figure 3.2.9.1 in a second step. Also in this case,
of non-industrial structures) and the number of full-time jobs several protection measures are possible and the economically
(in case of industrial structures). The values in percent speci- optimum measure should be taken provided that the following
fied in Table 3.2.9.2 are used to assign this total value to the applies to all relevant types of loss of public interest L1 to L3:
individual categories (animals: c a , buildings: c b , contents: c c , R < R
internal systems: c s ). For these values, it must be observed that T
the possible malfunction of electrical and electronic systems A lightning protection system according to IEC 62305-3
(internal systems) and the resulting follow-up costs are only (EN 62305-3) often sufficiently ensures that persons in the
included in the values for industrial structures, but not in the structure are protected (type of loss L1). In case of an office
values for non-industrial structures. and administration building or an industrial structure, types of

Type of structure Reference values Total value of c t
Low 300
Total reconstruction costs (do not include c t per volume
Non-industrial structures Ordinary 400
3
possible malfunction) (€/m )
High 500
Total value of the structure including buildings, Low 100
Industrial structures installations and contents (includes possible Ordinary c t per employee 300
malfunction) High (k€/AP) 500

Table 3.2.9.1 Values for assessing the total value c t (EN 62305-2)

Portion for Portion for the Portion for the Portion for Total for all
Condition animals building content internal systems goods
c a /c t c b /c t c c /c t c s /c t (c a +c b +c c +c s )/c t
Without animals 0 75 % 10 % 15 % 100 %
With animals 10 % 70 % 5 % 15 % 100 %
Table 3.2.9.2 Portions to assess the values c a , c b , c c , c s (EN 62305-2)

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