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h = 2.5 m + s
r
Warning: Keep off
the park deck during Additional
thunderstorms! air-termination
cable

h
Air-termination stud
Part No. 108 009

Conductors installed in concrete
or in the joints of the roadway
Height of the air-termination rod dimensioned
Discharge via steel reinforcement according to the required protected volume

Figure 5.1.6.1 Lightning protection system for a car park roof – Figure 5.1.6.2 Lightning protection system for a car park roof –
Protection of the building Protection of the building and persons (IEC 62305-3
(EN 62305-3); Annex E)

5.1.6 Accessible roofs Furthermore, e.g. lighting masts can also be used as air-termi-
It is not possible to mount air-termination conductors (e.g. nation rods to prevent life hazards. In this case, however, the
with concrete blocks) on roofs which are accessible by vehi- partial lightning currents which may enter the structure via the
cles. One possible solution is to install the air-termination con- power lines must be observed. Therefore, it is imperative to
ductors in either concrete or in the joints between the decks. establish lightning equipotential bonding for these lines.
If the air-termination conductor is installed in these joints, air-
termination studs are fixed at the intersections of the meshes
as defined points of strike. 5.1.7 Air-termination system for green and
The mesh size must not exceed the value specified for the rel- flat roofs
evant class of LPS (see chapter 5.1.1, Table 5.1.1.3). Green roofs can make economic and ecological sense since
they provide noise insulation, protect the roofing, suppress
If it is ensured that persons do not stay in this area during a dust from the ambient air, provide additional heat insulation,
thunderstorm, it is sufficient to take the measures described filter and retain rainwater and are a natural way of improv-
above. ing the living and working atmosphere. Moreover, green roofs
Persons who have access to the parking deck must be informed
by a notice that they must immediately clear this parking deck are publically funded in many regions. A distinction is made
when a thunderstorm occurs and not return for the duration of between so-called extensive and intensive green roofing. Ex-
the storm (Figure 5.1.6.1). tensive green roofing requires little effort, in contrast to in-
tensive green roofing which requires fertiliser, irrigation and
If it is likely that persons stay on the roof surface during a cutting. For both types of green roofing, either earth substrate
thunderstorm, the air-termination system must be designed to or granulate must be laid on the roof.
protect these persons from direct lightning strikes, assuming It is even more complicated if the granulate or substrate has to
they have a height of 2.5 m (with stretched arm). The rolling be removed due to a direct lightning strike.
sphere or the protective angle method can be used to dimen- If no external lightning protection system is installed, the roof
sion the air-termination system according to the class of LPS sealing can be damaged at the point of strike.
(Figure 5.1.6.2).
Experience has shown that, regardless of the effort required,
These air-termination systems can consist of spanned cables or the air-termination system of an external lightning protection
air-termination rods. The air-termination rods are fixed to e.g. system can and should be installed on the surface of a green
structural elements such as parapets or the like. roof.

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