What is a lightning?
Lightning is formed when clouds become charged by static electricity.
Positive and negative charges are located in the extreme sides of the cloud creating an Electric field, when a high value is achieved a spark takes place forming a pathway where charges move on, sorting out them and removing the potential differential, of course accompanied by a huge sound and flash.
Types of lightning
Lightning are classified according to the form of them:
- Intracloud: it’s when the lightning occurs internally within a cloud
- Intercloud: It happens when the lightning starts in a cloud and ends in another one.
- Cloud to Ground: this type of lightning involves cloud and the surface of planet earth. It can start in a cloud and finish at the earth, but it could also work all the way around. In order to keep the installation and building safe, a protection system against this kind of lightning is needed; imagine that a Cloud to Ground lightning impacts in an oil facility.
Lightning protection systems
In a general way, Lightning Protection Systems are basically composed by three items: Air terminals, wire conductors and grounding rods. Lightning Protection System is intended to attract and capture the lightning (by Air terminals) and carry all this current/energy (by wire conductors) to ground (Grounding system).
Air terminals are also known as lightning rod, strike termination, Franklin’s rod. They are made of conductive materials such as copper and alloys. There are a lot of manufactures and vendors that offer devices called Dissipation Array Systems (DAS) and Charge Transfer Systems (CTS) using the premise that these kind of systems are more effective than the conventional (Franklin Rod, above image) since can protect for larger radius from lightning. This statement is false and has not been approved and accepted by the regulatory institutes such as NFPA, CIGRE, IEC, ICLP, among others.