Understanding the Role of Lightning Rods in Protecting Structures and Lives

Understanding the Role of Lightning Rods in Protecting Structures and Lives

Sub : Geo

Sec: Climatology

Why in News

• With climate change causing an increase in lightning frequency and severity, lightning strikes have become more common and hazardous. India recorded 2,887 lightning-related deaths in 2022, leading to calls for lightning to be recognized as a natural disaster for better access to institutional protection. Lightning rods play a critical role in safeguarding people and structures from the destructive power of lightning strikes.

What is Lightning?

• Lightning is an intense electrical discharge between charged particles in a cloud and the ground. It occurs when the charge buildup in a cloud exceeds the insulating capacity of the surrounding air.
• Objects can act as conductors or insulators based on the electrical energy applied. For instance, air usually acts as an insulator but becomes conductive at high voltages (around 3 million V/m), enabling it to carry an electric current.
• Cloud-to-ground (CG) lightning is dangerous because it can electrocute people due to its high electric voltage and current. Inter- or intra-cloud lightning is visible and safe.

Process of Lightning:

• Lightning is caused by a difference in electrical charge between the top and bottom of a cloud, which generates a huge current of electricity.
• Water vapour in the cloud condenses and rises, generating heat and pushing water molecules further up until they become ice crystals.
• Collisions between the ice crystals trigger the release of electrons, leading to a chain reaction that results in a positively charged top layer and negatively charged middle layer in the cloud.
• When the difference in charge becomes large enough, a huge current of electricity flows between the layers, producing heat that causes the air column to expand and produce shock waves that create thunder sounds.
• Lightning seeks the closest object with high electrical potential, taking the path of least resistance. As it reaches the ground, it often targets tall structures, trees, or other elevated objects.

What is a Lightning Rod?

• A lightning rod is a metal conductor designed to intercept lightning strikes, providing a safe pathway for the electrical discharge to travel into the ground.
• Typically, lightning rods are pointed, which strengthens the electric field around them. This design creates an ionized path in the air, guiding the lightning to the rod and away from other structures.
• The rod’s pointed shape intensifies the electric field near it, similar to water flow speeding up at a nozzle. This concentrated electric field ionizes the surrounding air, forming a conductive path for the lightning.
• Lightning rods are connected to a grounding wire that directs the current safely into the earth, which has an almost infinite capacity to absorb charges.

About Lightning Arresters: Used in electrical systems, these devices divert high currents away from low-current components, protecting sensitive devices from surge damage.

The International Electrotechnical Commission sets guidelines on lightning rod design, installation standards, and risk assessment protocols. These standards help engineers minimize liability and maximize safety by establishing design priorities and points of failure.

Types of Lightning Rod Setups:

• Standard Rods: Installed on building tops to intercept direct strikes.
• Early Streamer Emission (ESE) Systems: Designed to initiate an upward streamer faster, attracting lightning to a preferred path.
• Dissipation Array Systems (DAS): Employ multiple small rods to reduce the electric field and prevent strikes in sensitive areas.