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Technical reference
IEC/BS EN 62305-1 - Lightning protection zones (LPZ)
Lightning protection zones (LPZ)
The concept of the Lightning Protection Zone (LPZ)
was introduced within IEC/BS EN 62305 particularly to
assist in determining the protection measures required
to establish protection measures to counter Lightning
Electromagnetic Impulse (LEMP) within a structure.
The general principle is that the equipment requiring
protection should be located in an LPZ whose
electromagnetic characteristics are compatible with the
equipment stress withstand or immunity capability.
The concept caters for external zones, with risk of direct
lightning strike, or partial lightning current occurring
(LPZ 0) and levels of protection within internal zones
(LPZ 1 & LPZ 2).
In general the higher the number of the zone (LPZ 2;
LPZ 3 etc) the lower the electromagnetic effects expected.
Typically, any sensitive electronic equipment should be
located in higher numbered LPZs and be protected against
LEMP by relevant Surge Protection Measures (SPM as defined
in BS EN 62305).
SPM were previously referred to as a LEMP Protection
Measures System (LPMS) in IEC/BS EN 62305:2006.
Figure 4 highlights the LPZ concept as applied to the
structure and to SPM. The concept is expanded upon in
IEC/BS EN 62305-3 and IEC/BS EN 62305-4.
Selection of the most suitable SPM is made using the risk
assessment in accordance with IEC/BS EN 62305-2.
Arandela de estanqueidad integrada: ajuste
garantizado, no puede perderse ni montarse
incorrectamente. Sin montaje
Figure 4. The LPZ concept
LPZ
0
Direct flash, full lightning current,
full magnetic field
Earth termination network
Rolling sphere
radius
Air termination
network
SPD
0
/1
Equipotential
bonding by means
of SPD
SPD
0
/1
Down conductor network
LPZ
0
No direct flash, partial
lightning or induced current,
full magnetic field
LPZ 1
No direct flash, partial
lightning or induced
current, damped
magnetic field
LPZ 2
No direct flash,
induced currents,
further damped
magnetic field
LPZ 3