Direct and Indirect effects on human beings
Lightning is second leading cause of death in the United States, where the average is 139 deaths caused by floods annually, 87 by lightning, 82 by tornados and 27 by hurricanes.Each year hundreds of people die during the storm season. The most frequent cause is lightning strike close to the area where they were sheltering or due to direct impact (struck by lightning). During a storm, the atmosphere’s electric voltage can reach values of 1,000 to 1,000,000 Volts between ionosphere and the earth.
Cases Deaths Situation
1 1 On the beach
1 1 Horseback riding
1 1 Fishing
1 10 In Church
1 3 Attending a Relative’s Burial
1 110 Traveling on a Plane
2 2 Camping on the Mountains
2 4 Taking a walk on the Countryside
3 9 Fulfilling a National Duty
3 18 Working
4 11 Being at home
10 23 Playing Football
11 24 Sheltering from rain under a tree
13 20 Not specified
Struck by lightning Deaths: Studies of different accidents that have occurred during the past 5 years resulting in death caused by lightning, shows that in most cases people were under a tree, taking a walk or working out in the fields. Some of the lifeless bodies show signs of the effects of lightning.
All or just part of the lightning discharge circulates through the body and in some cases clothing disappears. Death occurs because of the instant thermal and electric effects - in some cases the body is completely destroyed. Before impact, the victim feels a current that gives him/her goose bumps; after that it is instantaneous, there is no time for suffering due to the speed of the strike.
Death caused by passing voltage: The impact of an indirect lightning strike generates strong passing voltage on the earth which affects people who are in a range of 120 meters from the center of the strike. People affected by passing voltage may suffer different lesions in their body; the damage caused is proportional to the intensity of the lightning during the impact. This can cause serious wounds and also death.
Physical Effects:
- Cardiac arrest.
- Respiratory arrest.
- Brain Injury.
- Skin burns.
- Burst Eardrum.
- Retinal Injury.
- Fall due to expansive electric waves.
- Fall due to muscular contraction caused by a light passing voltage.
- Lung and bone Injuries.
- Post-traumatic stress.
The cause of these physical effects in people’s bodies appears directly on the earth or close to trees at the time of lightning impact, and appear especially because of the reaction of energy that transforms into Acoustic, electrochemical, thermal and electro dynamic effects. When lightning strikes on a metal structure or tip, “radiation” appears. These are the electromagnetic pulses that are generated during the electrical contact of lightning on any metallic element on earth. The radiated energy travels at light speed also generating a short reach expansive wave due to the sudden movement of the mass. Meanwhile the electromagnetic pulse spreads itself to large distances. In this way, it electrically affects large geographic areas, reaching 300 km; on its trajectory it generates induction that transforms into dangerous currents circulating through everything that protrudes from earth or is in contact with it. This reaction creates a difference in potential that can be represented by electric sparks with values higher than 15.000 Volts. The affected range varies proportionally according to the lightning’s intensity. Lightning discharges of more than 510 kA per microsecond have been measured, being on average 100 kA per second.
Direct and Indirect effects on installations:
The impact of lightning generates a wave of electricity on aerial cables that spreads through the network creating a high energy voltage.
Consequences:
Material destruction, premature aging of sensitive electronic components, disfunction of that equipment connected to the network that is in danger of fire.
VOLTAGE WAVE 1,2/50 µS CURRENT WAVE 8/20 µS
During a lightning strike an induction in electrical tension and communication lines are generated. All sensitive electronic equipment that is within a range of 1.500 meters might be affected by a over voltage induction.
Due to lightning strike intensity the ground cannot absorb all the energy discharged. This phenomenon might generate dangerous passing voltage on installations that are not prepared for this.
During a lightning strike, in less than 1 second, its energy circulates throughout the lightning rod in search of a low electrical resistance on earth. The electromagnetic pulse generated by the electrical contact of the strike on the lightning rod is the result of the temporary magnetic field created by the energy circulating on the lightning discharge channel. The neutral current flows very quickly compared to the impedance of the discharge channel and the cloud’s electrical charge. The growing range of these current pulses varies proportionally to their intensity and speed according to each strike.
Electrical repercussions appearing during a lightning strike and affecting sensitive electronic equipment:
- Electrostatic charge
- Electromagnetic pulses
- Electrostatic pulses
- Earth currents
- Temporary over voltages
- Resistive coupling
- Inductive coupling.
- Capacitive coupling.
It is estimated that during 2004 more than 40,000 accidents will be reported to the insurance companies in Canada due to direct or indirect effects caused by lightning. Compensation will exceed forty million dollars.
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Posted by: angel Rodriguez Montes | October 14, 2009 at 10:45 AM