Lightning ProtectionLightning Protection

Human Protection Building protection

Under thunderstorm conditions never be the tallest object in the area

If you are happened to be the first object to send the answering leader you will be struck by lightning

Do not perform the following acts under thunderstorm conditions

HikinHikingg

Riding Riding cycles on cycles on open spacesopen spaces

Staying on a

Playground

Beach

Open road

Roof Top or

Any Other Open Space

Sailing an open boatSailing an open boat

Repairing Telecommunication or Power linesRepairing Telecommunication or Power lines

Working on Cranes Working on Cranes and other high and other high elevated vehicleselevated vehicles

Working on Working on agricultural fieldsagricultural fields

Using elevated metal objects

Caught up outdoors in an intense thunder storm, it is very dangerous to get shelter under a tree

The large current that flows along the trunk of a tree as a result of a lightning strike may decide to jump into your head or hand and reach the ground through your body when you stand nearby.

This is termed a side flash

Getting a side flash

If you are in a building which is not protected against lightning under severe lightning conditions keep a distance of at least 2m away from the walls

The highest number of outdoor lightning accidents occur as people stay underneath large trees

Step Potential

Then a part of the lightning current will flow through your body which may paralyze you

When lightning strikes a place a potential gradient develops away from the point of strike

If a person keep his body radial to the potential gradient then he will be subjected to a potential difference

Lightning Flash

Current {`r`v

Ground

Step Voltage

pQyvr vQxv an\

wry

Situation just after the strike

Situation just before the strike

Stepped leader

Connecting leader

Animals are most often killed by step potentialAnimals are most often killed by step potential

Lightning killed 504 sheep when a stroke hit the ground in this rocky pasture in Utah. A stroke to high-resistance soil can produce exceptionally high voltage in the ground and

spread over an unusually large area.

Therefore according to the international Therefore according to the international

standards under heavy thunder storm standards under heavy thunder storm conditions you have to squat on the conditions you have to squat on the ground keeping the feet close together ground keeping the feet close together an cover your ears with handsan cover your ears with hands

Caught up outdoors in an intense lightning storm, the worst position is to lie down flat

If you lie down flat in a thunderstorm a lightning that strikes ground nearby may send a current through the soil, which may enter your body from head and leave from the feet thus damaging many of the vital internal organs. The best position to be in such a condition is to squat down on your feet and to rest the head on the knees.

Never sleep on floorNever sleep on floor

Touch potential

When you are touching an object which will be subjected to a lightning strike a part of the current may flow across your body

Therefore do not touch

metallic masts

flag poles

fences etc.

during lightning periods

Rubber boots or plastic rain coats will not give you any protection against lightning

The service lines such as power and The service lines such as power and communication cables extend many many communication cables extend many many kilometers over open lands thus they are kilometers over open lands thus they are exposed very much to lightning exposed very much to lightning

These lightning currents may enter near by utilities destroying all the equipment connected to the service lines irrespective of the fact whether they switched on or off

Under such circumstances a person using the service (eg. Telephone) may be severely injured (even dead)

It is a high risk to repair electrical networks (house wiring etc.) during thunderstorm periods

Similar to telephones, a large current may propagate through a power cable in the event of a lightning strike. This current may reach a person who repairs the network even if the main switch is off.

Is it safe to be inside a car when lightning striking around?

YESIn a sturdy metallic object such as a car, you will get the Faraday Cage protection

Keep your body away from the metallic frame. Keep your hands on the lap. Do not use hand-free phones

But be careful !!

Some modern cars are made with fiber glass body parts.

Some cars have removable plastic roofing

Both of these types are not very good for lightning protection

A person struck by lightning does not retain any charge. Thus please attend to him and give the first aid as soon as possible

90% of the lightning victims can be saved from death if first aid is given in time

In 1998, in a provincial football match played in Congo, 11 players were killed by a single lightning struck on the ground.

In 2001, in Sri Lanka, 5 women were killed by a lightning strike as they were getting the shelter of a big tree.

In 2005, in Bangladesh 8 people were killed when lightning struck a tent with metal roof

Thus under lightning conditions keep at least 2m between two people

One lightning Killing many people

Lightning Striking a Person with Wet ClothesLightning Striking a Person with Wet Clothes

If you are lightning struck while wearing If you are lightning struck while wearing wet clothes, the lightning current may wet clothes, the lightning current may decide to take an external path as the decide to take an external path as the resistance of wet clothes is less. Thus you resistance of wet clothes is less. Thus you may be saved only with few skin burns.may be saved only with few skin burns.

What else I can do when lightning strikes around?

Avoid taking a bath either indoor or outdoor

Do not carry metal objects such as agricultural tools, back packs, umbrellas with metal tips etc.

Wet clothes are better than dry clothes

If you are in a group, spread out. Keep a distance of about 2m in between two people

Are there areas with high lightning densityAre there areas with high lightning density

Yes!Yes! For an example, in Sri Lanka For an example, in Sri Lanka there are small pockets of areas which there are small pockets of areas which are having acute lightning related are having acute lightning related problems. problems.

Reason?

Nobody Knows

Benjamin Franklin

QuestionQuestion??