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Lightning protection zones Outer zones:
LPZ 0 : Zone in which the threat is due to direct lightning
A
in buildings equipped with strikes and the undamped lightning electromagnetic field.
Systems such as cables extending beyond the building may
safety systems be subjected to the full lightning current.

LPZ 0 : Zone protected against direct lightning strikes, in
B
Building management, telecommunication, control and sa- which, however, the undamped lightning electromagnetic
fety systems are increasingly used in all areas of residenti- field is present. Systems such as alarm lights or sirens may be
al and functional buildings. These networked systems make subjected to partial lightning currents.
the building intelligent and ensure its optimised use. Building
owners and operators make high demands on the availa- Inner zones:
bility and reliability of these systems. An external lightning Inner zones are protected against direct lightning strikes and
protection system protects persons and material assets in a are subdivided into:
building from fire, however, electrical and electronic systems
are not protected against failure as a result of surges caused LPZ 1: Zone in which impulse currents are limited by current
by a lightning discharge. A lightning protection zone concept distribution and SPDs at the zone boundaries. Spatial shiel-
in conformity with the IEC 62305-4 standard provides effec- ding may attenuate the lightning electromagnetic field. Ring
tive protection against surges caused by a lightning electro- conductors with detectors are frequently installed in LPZ 1.
magnetic impulse (LEMP). According to this principle, the
structure to be protected must be subdivided into inner light- LPZ 2: Zone which, in comparison to LPZ 1, is additionally
ning protection zones with different LEMP threat values. It is protected against impulse currents and the lightning electro-
advisable to match the lightning protection zones and their magnetic field and is thus subjected to a lower interference.
LEMP threat values with the withstand capability of the rele-
vant electronic system. LPZ 3: Zone which requires maximum protection against the
effects of a lightning strike. Electronic systems such as fire
The above figure exemplarily shows the lightning protection control panels are frequently installed in LPZ 3. Surge arres-
zones of a fire alarm system according to the type of light- ters and shielding measures reduce impulse currents and
ning threat:
electromagnetic fields to an acceptable level for the system
technology.

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