Solutions for direct lightning
Lightning is called one of the worst natural disasters in the planet.
It has been defined as 'a natural hazard, being the discharge of static
electricity generated in parts, called 'cells', of storm clouds, Some of
them damage buildings and a few kill or injure people and animals,
either directly or indirectly by causing fire and explosions.'
There said to be about 2,500 lightning strikes to the Earth surface
in every second and tendency of lightning hitting a person is one in six
People use an increasing amount of sophisticated electronics
equipments resulting from the advancement of science and technology. The
same advancement inherited us with deforestation, high-rising buildings
and drastic environmental impact that make the planet earth hotter every
day and that makes it more vulnerable for lightning affects. This
compelled engineers and technologists to put their minds together and
find a way out of the impending danger. The solution they had evolved
caused far reaching changes in the professions of entrepreneurs,
installers and inventors to change all the previously existed standards
and called upon them to take extra time to figure out the most suitable
technologies to protect people and property in the event of lightning.
There are two main standards of lightning protection systems -
conventional and non-conventional. The conventional standard includes
Curtnary wire, Faraday cage, Ring Conductors, and Finials etc. combined
with down line lightning standards. The non-conventional standards
consist of enhanced protection radius with inclusion of passive or
active elements (ESE) combined with down line lightning protection
standards and hybrid system which contains indigenous technologies that
have been used along with modern theories.
Despite reservations and criticisms from scientific minds of several
European nations on the unorthodox technologies used in the
non-conventional standards, the trend is that they are widely employed
elsewhere in the world. In Sri Lanka, there is no specific standard when
it comes to lightning protection. There are about 10 to 15 foreign
brands available here until recent times and most of them came from the
Europe. The situation has now changed with the proliferation of cheaper
options flooding from China.
In comparison of the cost between the conventional standards and
nonconventional standards, the latter is very much less expensive.
When it comes to talk of methods applied for direct protection from
lightning hazard under the conventional system we find Faraday cage
(Curtanary wire, ring conductors), array of spikes on the roof with
associated down conductors, steel roof and structures themselves used as
a down conductor with associated grounding network which is cost
There is another cost effective method of using steel flashing and
steel gutters as a complementary down conductors with associated direct
lighting protection system.
The non-conventional or ESE systems have been developed in the Europe
where there are so many laboratories to test units of lighting
But they have received heavy flack from some orthodox scientists who
do not accept these units claiming that they would not be functional
under the real life situations.
This while the situation in the world of modern day lightning
protection, we in Sri Lanka see that some of our scientists and
engineers continue to waste money for spending on copper in devising
lightning protective systems. Sadly they continue to do so without
testing any other scientifically proven methods or long standing
experience in logical outset. We also see some steel roofs too have been
recommended to laying the conductors as a dedicated lightning conductor
that could be resulting in unnecessary issues of corrosion or side flash
Standards should be used as a guide line but not as a methodology.
Transgression of this maxim sees there has been abuse of standards
recommended to lay ring conductors - if the given location is steel
bonded, it is an utter waste of money to lay an additional conductive
Presently, almost all the buildings are composed with conductive
gutters or steel prefabricated buildings. Thus engineers should be extra
vigilant in figuring out the solutions in order to economize the project
with positive technicality.
Carrying out a comprehensive risk assessment prior to selecting a
lightning protection scheme has been now accepted as a practice. This
could be done by considering the natural fabric of the building or
location or Ohmic Resistance Value - number of electrodes to be driven,
necessity of ring conductors, local soil conditions, adjoining
structures and trees, and the Ufer grounding etc.
(The Ufer Ground is an electrical earth grounding method developed
during World War II. It uses a concrete-encased electrode to improve
grounding in dry areas. The technique is used in construction of
concrete foundations.) In selecting a lightning protection it should
also be noted that no lightning protection system is 100 percent
effective. A system designed in compliance with the standard does not
guarantee immunity from damage.
Lightning protection is an issue of statistical probabilities and
risk management. It is not economically viable to spend the world best
system for the protection scheme. What could be advisable is that one
should figure out an economically sound system with service back up as
an official protection provider.
Secondary effects of lightning
Lightning is a capricious, random and unpredictable event. According
to Fundamentals of Lightning published by the National Lightning Safety
Institute of the USA its' physical characteristics include current
levels sometimes in excess of 400 kA, temperatures to 50,000 degrees F.,
and speeds approaching one third the speed of light. Globally, some
2,000 on-going thunderstorms cause about 100 lightning strikes to earth
Lightning effects can be direct and/or indirect. Direct effects are
from resistive (ohmic) heating, arcing and burning. Indirect effects are
more probable. They include capacitive, inductive and magnetic
Lightning "prevention" or "protection" (in an absolute sense) is
Lightning could strike any given installation and bursts all the
connected equipments with direct or indirect effect that has the power
of reducing them to ashes in a minute.
Right solutions is not be panic or run away but learn to live with
danger with the help of technology called power line surge protection
Today non-liner arrays are the most common sources of protection
widely used such a, MOVs/ZOVs, SAD, capacitors, resistors,
electro-static devices and linear filters, inductive dampers, isolation
transformers, PTC etc. When selecting a surge protector, it is advisable
to refer the limiting voltages/clamping voltages, working voltages,
warranty and after sales services need to be verified. All these should
be coordinated with local voltages, earthing profiles, equipments
capacities, local ionization qualities of the soil etc.
However it is sad to say that these requirements are never met by
some of foreign brands available. They are highly priced and used only
by people who do not have a technical will or those worry of individual
perks without national interest to save much needed foreign exchange.
Most of the local engineers despite their high awareness on energy
armed with analytical skills have become good critics than becoming
designers, researchers or developers that they trained to be.
That is why our electrical and electronics engineering are said to be
about 10 years behind the rest of the world. Hardly anyone develops a
local industry. This is amplified by the fact that most of decision
makers lack the knowledge of saving foreign exchange by promoting the
electrical and electronic engineering field.
In the practical scene what we see when looking at domestic
installations is the tendency that in most of places, electricians who
did the electrical installation, have later become technical
consultants. When any related issue arises their employers tend get the
electricians advice rather than experts' advice or looking for a proper
(The writer is a chartered electrical engineer)