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Properties of the structure or internal systems –
Protection measures R A R B R C R M R U R V R W R Z
Physical restrictions, insulation, warning notice, potential control • •
on the ground
Lightning protection system (LPS) • • • • a • b • b
Surge protective device for lightning equipotential bonding • • • •
Isolating interfaces • c • c • • • •
Coordinated SPD system • • • •
Spatial shielding • •
Shielding of external lines • • • •
Shielding of internal lines • •
Routing precautions • •
Equipotential bonding network •
a Only for grid-like external LPS
b Due to equipotential bonding
c Only if they belong to equipment to be protected
Table 3.2.8.1 Lightning and surge protection measures and their influences on the individual risk components

where
C P stands for the costs of protection measures; Define the value of the:
i is the interest rate (for financing the protection meas- – Structure and the associated
ures); activities
– Internal systems
a is the amortisation rate (calculated by the service life
of the protection measures);
Calculate all risk components R X
m is the maintenance rate (also includes inspection and
maintenance costs). relevant to R 4

Thus, the procedure assumes that costs can be (roughly) esti- Calculate the annual costs of the
mated before actually planning lightning and surge protection total loss C L and the costs of the
measures. (General) information on interest rates, amortisa- remaining loss C RL if protection
tion of protection measures and planning, maintenance and measures are taken
repair costs must also be available. Protection makes economic
sense if the annual saving S M is positive: Calculate the annual costs of the
S =C (C +C ) protection measures C PM
M L PM RL
Depending on the size, construction, complexity and use of the Yes Protection measures
structure and the internal systems, different protection meas- C PM + C RL > C L do not make
ures can be taken. Thus, there are several possibilities to pro- economic sense
tect the structure. The profitability of protection measures can No
therefore be further examined even if an economically sound Protection measures
solution has already been found since there might be an even make economic sense
better solution. Consequently, an economically optimal solu-
tion can and should be achieved.
For examining the profitability of protection measures as de- Figure 3.2.9.1 Flow diagram for selecting protection measures in
scribed in this chapter, possible damage, namely the loss in case of loss of economic value

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