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loss L2 and L3 are not relevant. Consequently, other protection In addition to international requirements, country-specific ad-
measures (e.g. surge protection) can only be justified by exam- aptations are integrated in the software and are constantly up-
ining their profitability. In these cases, it quickly becomes evi- dated. The software, which is available in different languages,
dent that loss of economic value can be significantly reduced is a tool for specifically defining and implementing lightning
by using coordinated SPD systems. and surge protection measures (Figure 3.3.1).

The following design assistances are available:
3.2.10 Calculation assistances ¨ DEHN Risk Tool; risk analysis according to IEC 62305-2
The IEC 62305-2 (EN 62305-2) standard includes procedures (EN 62305-2)
and data for calculating the risk in case of lightning strikes ¨ DEHN Distance Tool; calculation of the separation distance
to structures and for selecting lightning protection measures. according to IEC 62305-3 (EN 62305-3)
The procedures and data listed in the standard are often
complex and difficult to implement in practice. This, however, ¨ DEHN Earthing Tool; calculation of the length of earth elec-
should and must not stop lightning protection specialists, in trodes according to IEC 62305-3 (EN 62305-3)
particular planners, to deal with this topic. The quantitative ¨ DEHN Air-Termination Tool; calculation of the length of air-
assessment of the risk of lightning damage for a structure is termination rods according to IEC 62305-3 (EN 62305-3)
a significant improvement compared to the previous situa-
tion where decisions in favour of or against lightning protec-
tion measures were often based on subjective considerations 3.3.1 DEHN Risk Tool; risk analysis according
which were not understood by all parties involved. to IEC 62305-2 (EN 62305-2)
Thus, such a quantitative assessment is an important pre-
requisite for the decision whether, to what extent and which The DEHN Risk Tool considerably facilitates the complex and
lightning protection measures must be taken for a structure. difficult method of assessing the risk for structures. The ground
This ensures that lightning protection is widely accepted and flash density N G in the area where the object to be protected is
prevents damage in the long term. located can be determined in the integrated customer / project
It is virtually impossible to apply the procedure stated in the management.
standard without tools, namely without software tools. The In addition to the ground flash density, the calculation basis
structure and contents of the IEC 62305-2 (EN 62305-2) stand- must be selected in the DEHNsupport customer / project man-
ard are so complex that tools are indispensable if the standard agement. To this end, different countries and their country-spe-
is supposed to gain ground on the market. Such a software cific standard designations are available. This selection does
tool is e.g. Supplement 2 of the German DIN EN 62305-2 not only define the standard designation for the printout of the
standard, which includes a calculation assistance based on calculations, but also activates country-specific calculation pa-
an EXCEL sheet with print option. Moreover, commercial pro- rameters. As soon as a calculation is opened for the first time,
grams based on databases are available, which also reflect the the defined calculation basis cannot be changed any more.
full functionality of the standard and allow to edit and store
additional project data and other calculations, if any.

Author of chapter 3.2:
Prof. Dr.-Ing. Alexander Kern
Aachen University of Applied Science,
Jülich campus Phone: +49 (0)241/6009-53042
Heinrich-Mußmann-Str. 1 Fax: +49 (0)241/6009-53262
52428 Jülich, Germany [email protected]

3.3 DEHNsupport Toolbox design
assistance
A computer-aided solution makes it easier to design a light-
ning protection system for structures.
The DEHNsupport Toolbox software offers a number of calcula-
tion options in the field of lightning protection based on the
requirements of the IEC 62305-x (EN 62305-x) standard series. Figure 3.3.1 Start screen of the DEHNsupport Toolbox software

www.dehn-international.com LIGHTNING PROTECTION GUIDE 49