Furse Total Solution to Earthing & Lightning Protection

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Furse, Wilford Road, Nottingham, NG2 1EB • Tel: +44 (0)115 964 3700 • Email: • Web:
Lightning protection to NFPA & UL standards
TSC-0912 - 09.10.12
Within certain markets installation of an LPS,
including component selection, is governed
by American NFPA and UL standards rather than
their BS EN/IEC equivalent.
The appropriate standards for lightning protection in
these markets are:
UL 96 Lightning Protection Components
UL 467 Grounding and Bonding Equipment
NFPA 780 Standard for the Installation of Lightning
Protection Systems
UL 96A Installation Requirements for Lightning
Protection Systems
UL 96 and UL 467 are product standards for lightning
protection components; NFPA 780 and UL 96A are
application standards governing satisfactory
installation of an LPS.
UL 96 & UL 467
These standards define the requirements for lightning
protection components, including their design,
material composition, performance and testing to
ensure they are suitable for application in an LPS.
UL 96 covers above ground lightning protection
components, including:
Air termination components (air terminals & bases)
Conductors
Connector fittings (conductor clips, clamps,
bimetallic connectors & bonding plates etc)
Components are divided into 3 Classes, to reflect their
intended application (Class l, Class ll, Class ll modified).
UL 467 covers grounding (UK - earthing) and bonding
equipment used to create a grounding system in line
with the requirements of NFPA 780. Products include:
Ground clamps, bushings & fittings
Grounding electrodes (rods/plates) & ground mesh
Products are determined suitable for use in an LPS
following testing and evaluation by UL. Where a
product successfully passes UL evaluation it may carry
a UL Mark appropriate to the testing carried out.
Installation of lightning protection
systems to NFPA 780/UL 96A
Application standards NFPA 780 and UL 96A cover
assessment of risk from lightning and installation of
an appropriate LPS.
Structures to be protected are defined as one of two
classes, as follows, which correlates back to the product
grade which should be installed:
Class l: buildings less than 75 feet in height
Class ll: structures greater than 75 feet in height,
and special structures such as heavy duty stacks
and steeples
Three options are proposed for the design of air
termination systems:
Air termination placement: Air terminals are
placed in a grid pattern at intervals of up to 20 or
25 feet (dependent on air terminal height), with a
relaxation in the spacing if air terminals are not on
the perimeter of the structure (for roof lengths or
widths exceeding 50 feet). These spacings apply to
flat or gently sloping roofs only with more
complex roof structures requiring specific design
to protect all parts
Rolling sphere method: Similar in principle to
BS EN/IEC 62305, though with a single sphere
radius of 150 feet. At all times the rolling sphere
should only be in contact with the tips of the air
terminals and not the fabric of the structure
Protective angle method: Based on the ratio of
height/size of a higher building with regard to a
lower one. It does not apply for structures over 50
feet in height, where air termination placement or
the rolling sphere should be used
Installed air terminals (air rods) should not be less than
10” in length or 3⁄8” in diameter, and where above 24”
in height require bracing at minimum half their height.
There should be at least two down conductors from air
termination system to the grounding system, which
should be secured to the structure with suitable
connectors at intervals no more than 3 feet apart.
Air termination and down conductor components can
be manufactured from copper, copper alloy or
electrical grade aluminium, unless otherwise specified,
on the proviso that:
Copper components should not be in contact with
aluminium or external galvanized steel surfaces
Aluminium products should not be in contact with
the earth, be set in concrete or masonry, be
installed in wet locations, or be in contact with
coated surfaces using alkaline paint
The grounding system for lightning protection should be
bonded to all other grounding systems at the structure,
including those for power and communication, as well as
underground metallic services (utilities etc).
The bonding conductor should be the same size as the
main down conductor and main system conductor.
Grounding electrodes can be rods or plates. Rods
should not be less than 1⁄2” in diameter and 8 feet in
length, and should be manufactured from
copperbonded steel, solid copper or stainless steel.
Grounding arrangements using ringed conductors or
steel rebars are also acceptable.
For further information or to discuss LPS design in line
with NFPA and UL standards, please contact us.
Note: products shown in this catalogue with the UL
Mark have been successfully evaluated by UL.