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Risk assessment Lightning protection zone concept

A lightning protection risk analysis allows you to assess and determine the risk In case of the lightning protection zone concept, the building is divided into zones

potential for structures. This risk analysis forms the basis for minimising risks and with different risk potential. Inner and outer lightning protection zones are defi-
defining economically optimal protection measures – Tailored to the existing ned depending on the lightning threat. Based on these zones, it is determined
structures and their use. where which measures are required.

Modern structures and buildings are becoming smart. They to surges caused by lightning discharge. The principle of
are based on a variety of networked technical components: lightning protection zones (LPZ) according to IEC 62305-4
Predictive risk management involves calculating risks for the Lightning protection risk analyses aim to objectify and Building management, telecommunication, control and describes effective protection against surges caused by light-
company. It provides the basis for decisions to limit these quantify the risk posed by direct and indirect lightning security systems to name but a few. Failure of individual ning electromagnetic impulse (LEMP).
risks and shows which risks should reasonably be covered by strikes to structures and their contents. technical building equipment components can have
insurance. far-reaching consequences and even bring the entire According to this principle, the structure to be protected
building to a standstill. should be divided into inner lightning protection zones of
The risk analysis specified in IEC 62305-2 ensures that a different LEMP threat values. Suitable LPZ can be defined
The risk of lightning strikes must also be specifically lightning protection concept can be drawn up that is Although external lightning protection protects people and depending on the number, type and sensitivity of the
considered for companies using extensive electronic comprehensible to all parties involved and technically and material assets in buildings from the risk of fire, it does not electronic devices / systems.
equipment for production or providing services. It should be economically optimised, i.e. can ensure the protection protect the electrical and electronic systems from failure due
noted that losses incurred due to the lack of availability of required at the lowest possible cost. The protection
electronic systems and, as a result, production or services, measures resulting from the risk analysis are described in Outer zones: Inner zones:
coupled with the potential loss of data often by far exceed detail in parts 3 and 4 of the IEC 62305 series.
the physical damage to the hardware of the relevant system. LPZ 0A: Zone where the threat is due to direct lightning Inner zones are protected against direct lightning strikes.
strikes and the unattenuated lightning electromagnetic field. They are divided into:
The systems affected, such as lines extending beyond LPZ 1: Zone where impulse currents are limited by current
buildings, may be subjected to the full lightning current. sharing and surge protective devices at the zone boundaries.
Procedure: LPZ 0B: Zone protected against direct lightning strikes, but Spatial shielding may attenuate the lightning electromagnetic
Assessment of the structure Definition of protection measures where the threat is the unattenuated lightning electromag- field. Ring lines with detectors are often installed in LPZ 1.
netic field. The systems affected, such as alarm lights or
In a first step, the building is assessed based on its equip- The protection measures are defined based on the determi- sirens, may be subjected to partial lightning currents. LPZ 2-n: Zone which, compared to LPZ 1, is additionally
ment, location and risk potential. The result of this assess- ned risk. These include, for example various equipotential protected against impulse currents and the lightning
ment is a so-called risk R / whether the determined risk bonding measures or definition of a class of LPS (LPL, electromagnetic field and is therefore subject to less
exceeds a tolerable value Rt. The figures below show a simp- Lightning Protection Level) and thus external lightning interference.
lified representation of the relationship between the type of protection measures. The aim is to reduce the risk to an
damage, source of damage and type of loss and provide an acceptable level. After that, internal lightning protection
initial overview of the risk potential. measures (surge protection) are then taken. These are based FCP: Fire control panel
on the so-called lightning protection zone concept. FBKD: Fire brigade key depot
FBIOS: Fire brigade information
and operating system
M LV / Low voltage / main
MDB: distribution board
M
SDB: Sub distribution board
Risks Risks
SDB

Fire Fire charging FBIOS
post SDB medical
device
FBKD
server
Human Human
Surges Surges
LV / MDB
Source of damage S1: Lightning strike to a structure Source of damage S3: Lightning strike to an incoming supply line FCP

Simplified diagram
Risks Risks

Experience has shown that hospitals are designed according to class of LPS 2. This includes a defined
risk as well as the necessary external lightning protection, equipotential bonding and surge protection
Surges Surges measures. In addition to risk management, statutory and normative regulations such as the relevant
building regulations, IEC (or EN) specifications or fire protection requirements must also be observed
Source of damage S2: Lightning strike near a structure Source of damage S4: Lightning strike near an incoming supply line for hospitals.

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