lightning protection system for a building - introduction - types

1. LIGHTNING
PROTECTION
SYSTEM

2. Lightning is a sudden electrostatic discharge that occurs during
a thunderstorm. This discharge occurs between electrically
charged regions of a cloud (called intra-cloud lightning or IC),
between two clouds (CC lightning), or between a cloud and the
ground (CG lightning).
TYPES OF STRIKES AND LIGHTNING
Different types of strikes
➢ Cloud to ground
➢ Ground to cloud
➢ Cloud to cloud
Types of lightning
➢ Normal lightning
➢ Sheet lightning
➢ Heat lightning
➢ Ball lightning
➢ Red sprite
➢ Blue jet
COLORS OF LIGHNING
➢ Blue lightning within a cloud indicates the presence of hail
➢ Red lightning within a cloud indicates the presence of rain
➢ Yellow/orange lightning occurs when there is a large
concentration of dust in the air
➢ White lightning is a sign of low humidity. white is the colour of
lightning that most often ignites forest fires

3. EFECTS
• Physical damage - Fire, explosion, mechanical destruction
• Injuries/death to living being

4. LIGHTNING PROTECTION SYSTEM
It provides a means of which electric discharge may enter or leave
earth without passing through and damaging non-conducting parts
of a structure
It provides a means for controlling and preventing damage by
providing a low resistance path for the discharge of lightning
energy.
A lightning protection system includes a network of air terminals,
bonding conductors, and ground electrodes designed to provide a
low impedance path to ground for potential strikes.
There are four main parts of a properly installed lightning
protection system: copper air terminals, copper cable, copper clad
ground rods, surge suppressors. The air terminals and cable are
typically copper, but sometimes they can (or must) be aluminum

5. 1. Rods or 'Air Terminals' - The small, vertical protrusions designed to
act as the 'terminal' for a lightning discharge. Rods can be found in
different shapes, sizes and designs. Most are topped with a tall,
pointed needle or a smooth, polished sphere. The funtionality of
different types of lightning rods, and even the necessity of rods
altogether, are subjects of many scientific debates.
2. Conductor cables – heavy cables that carry lighting current from
the rods to the ground . cables run along the tops and around the
edges of roofs, then down one or more corners of a building to the
ground rods
3. Ground rods – long thick heavy rods buried deep into the earth
around a protected structure. The conductor cables are
connected to these rods to complete a safe path for a lightning
discharge around a structure

6. When lightning strikes a house, the electricity often surges through a
home's wiring or plumbing system, searching for the quickest possible
route to the ground. ... The most common place for a fire to ignite is
in the attic, when a lightning bolt comes through the roof or top of
the house
Self-protection
Steps
Avoid using any plumbing during lightning storms. ...
Avoid using your corded landline telephone during lightning
storms. ...
Don't use appliances that are plugged into the wall during lightning
storms. ...
Avoid standing on surfaces in which moisture or water is present
during lightning storms.
Avoid concrete floors and walls.

7. Lightning rods
Lightning rods provide a safe path for lightning to ground, they are
placed on the highest point of a building, and an upward leader from
the rod connects with a downward stepped leader.
The rod which is grounded provides a safe path for the electricity to
reach the ground.
Cables are fastened at every 3 feet. Vents and antennas are
connected with clamp or lug within 6 feet of the lightning cable. For
a neat job the cables are allowed to run down next to or behind
down spouts, molding, etc. and are connected to ground rods (make
connections to ground rods or ground plates below ground).
A lightning arrester is a device used on electrical power systems and
telecommunications systems to protect the insulation and
conductors of the system from the damaging effects of lightning.
The typical lightning arrester has a high-voltage terminal and a
ground terminal.
Each system’s design requires the following:
The air terminal or strike termination device must be positioned so
that it is highest point on the structure
The lightning protection system must be solidly and permanently
grounded. Poor /high resistance connections to ground are the
leading cause of lightning system failure for each of these systems
None of these systems claim to protect against 100% of the
possibility of a lightning stoke arriving near protective area.

8. THREE TYPES OF BUILDING PROTECTION
ARE USED:
• THE LIGHTNING ROD (simple rod or with triggering system)
The lightning rod is a metallic capture tip placed at the top of the
building. It is earthed by one or more conductors.
Need of several rods
for a large building
Damage the aesthetic
of the building
Passive system that
leads to instable
priming

9. • THE LIGHTNING ROD WITH TAUT WIRES
These wires are stretched above the structure to be protected they
are used to protect special structures – rocket launching areas,
military applications and protection of high voltage overhead lines.
Used
when
not
possible to fix elements on building.

10. THE LIGHTNING CONDUCTOR WITH MESHED CAGE
This protection involves placing numerous down conductors/tapes
symmetrically all around the building
This type of lightning protection system is used for highly exposed
building housing very sensitive installations such as computer
rooms
Passive solution
Costly solution
Damage the aesthetic of
the building