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This
illustration is designed to demonstrate the main aspects
and individual components of a structural lightning protection
system.
It is not intended to represent an actual scheme conforming
to a particular code of practice.
The drawing is not to scale.
Click on a link (on the right) for details.
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Conductors
The
first choice faced by the designer of a structural lightning
protection system is the type of conductor system to be used. |
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Choose
the material required, ie copper or aluminium |
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Choose
the type of conductor required, ie tape, solid circular
or stranded |
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Down conductor network |
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down conductor system is the means of carrying the current
of a lightning strike safely to the earth termination
network. |
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Conductor fixings |
| Select
the correct system of fixings for each part of the conductor
system. Fixings are available for a wide range of modern
construction materials, eg brick, stone, plastic and metal. |
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Air termination network
The air termination network is the point of connection for a
lightning strike. It typically consists of a meshed conductor
arrangement covering the roof of the structure.
Air terminals |
| Use
air terminals in the form of vertical air rods for the
protection of prominent roof top features or equipment.
Use strike pads to expose concealed conductors.
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Air terminal bases |
| Choose
the correct air terminal base. This will ensure that the
vertical air rods are both solidly fixed to the fabric
of the structure and have a low resistance connection
to the conductor network. |
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Conductor jointing clamps
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| Select
a component for the interconnection of multiple conductors
or for changes of direction. Jointing clamps will ensure
a low resistance, corrosion resistant connection. |
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Test clamps |
| In
order to allow periodic disconnection and testing of the
earth termination network, select a test clamp to be placed
within the run of each down conductor. |
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Earth termination network
The means of dissipating the current to the general mass of
earth.
Earth electrodes |
Choose
an earth electrode to suit the ground conditions in the
locality of the structure.
Electrodes are available in the form of rods
and plates (lattice or solid). |
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Earth rod clamps |
| Select
a high copper content alloy earth rod clamp for the connection
of the earthing conductor to the earth rod. In this below
ground application, the clamp must ensure a good electrical
contact and resist corrosion throughout the lifetime of
the installation. |
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Earth inspection chambers |
| Select
an earth inspection chamber to protect the earth electrode
connections. High strength chambers are available in plastic
and concrete. |
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Bonding
Bonding is the most commonly employed method of avoiding the
damaging effects of side flashing. All continous metalwork should
be considered for bonding. All metallic services, eg cable armouring,
gas, water or steam piping, entering the building should also
be bonded as directly as possible to the earth termination network.
Bonds
to metalwork |
| Select
the correct type of metalwork bond for the application,
ie a flat column face, a circular rainwater pipe or a
ribbed reinforcing bar. |
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