Despite intensive research, there are safety mangers and companies that fail to understand the magnitude of damage lightning can have on their assets. About 2.34 million cloud-to-ground lightning occurs in just Canada and it hits their economy hard.
According to reports, the Canadian economy suffers a loss between $600 million to $1 billion each year, and about 40 percent of this amount is allocated to property damage. In addition, one percent of the building fire is also due to the Lightning.
Since lightning tends to pose a significant threat to the building structure, electronics, and its occupants, thus it is important to understand all the key concepts. In the course of this article, we will be covering the following
- What is lightning?
- Lightning Protection System
- Five important Elements for an Effective Lightning Protection System
With vast practical experience supported by theoretical knowledge, Mechtronica design and engineering team can provide analytical and detailed studies for the design of lightning protection system by;
- Calculating the expected lightning strike frequency based on sire geographic location
- Evaluating the permissible risk based on buildings’ construction, contents, occupancy, and immediate surroundings.
If the above studies reveal that the site needs protection against lightning, our team will proceed with designing the system considering CAN/CSA-B72-M87, NFPA 780, IEC 62305, or any other applicable local Standards and Regulations.
What is Lightning?
Lightning is a natural phenomenon, it is a short-lived electric arc or a spark discharge. Lightning can take place between clouds or between the ground and the cloud. You come across lightning during a thunderstorm and it involves an exchange of electric charges.
In simple words, we can that lightning is a flow of electric current. Sometimes lightning starts from the ground, however, this mainly depends upon the polarity of the electrostatic charge. The most common lightning discharge negative cloud to ground discharge.
About 90 percent of the lightning discharge between the cloud and the ground is negative. Other less common types of discharge include positive ground to cloud lightning, positive cloud to ground lightning and negative ground to cloud lightning.
Lightning Protection System
Voltage surges and lightning put assets and people at risk. The discharge can occur in both rural as well as urban areas; therefore, it is imperative to have a lightning protection system in place in order to save people, assets and millions of dollars.
A lightning protection system provides protection against lightning by providing a safe path for the lightning to reach the ground. It consists of both external and internal lightning protection measures. A good lightning protection system tends to protect buildings from damage, people from death or injuries and electrical equipment from failure.
Five Important Elements for an Effective Lightning Protection System
Effective lightning systems need to have the following elements.
Air terminals or better known as the lightning rods are metal tubes that a lightning protection company place on the projecting high point of a building including a water tank, a flagpole, a dormer, or the peak. This allows the system to intercept the lightning bolt.
Copper and aluminum are the most favored metals for the lightning rods. However, it is important to have the right thickness. For solid aluminum rods, the minimum diameter should be ½ inch and in case of solid copper, the rod should have a minimum of 3/8 inches diameter. These rods should be extended above the projecting object; the distance should be between 10 to 36 inches.
Usually, the maximum length of a rod is 24 inches, but if a longer rod is used, it will require extra support. The best spacing is to place the rod 20 feet apart if it is less than 24 inches, and 25 feet apart when it is longer than 24 inches. Placing the rods strategically will ensure that lightning strikes on these rods, instead of the building.
In order to direct the lightning strike deep into the earth, you need to use conductors connected to the air terminals. These conductors can be either aluminum or copper. Once the lightning enters the earth, it is safely dissipated.
A good practice is to use either a copper conductor or an aluminum one. Using a conductor made out of copper and aluminum may lead to a chemically corrosive action or galvanic between the two elements. The lightning rods form a connection between the main conductor and the down conductors. These rods then connect the down conductors to the ground connections.
Ground connections come in play to safely, dissipate the lightning charge. The type of ground connection depends upon the soil conductivity of a respective area. An effective ground electrode should be 10-foot long solid copper or copper-clad steel. It should have a minimum ½-inch diameter and needs to be put at least 8 feet into the ground.
Bonding includes branch conductors that form a connection between the metal objects including water pipes, ventilation fan, etc. and the ground system to provide protection against side-flashes. To ensure effective grounding and to eliminate lightning side-flashes, it is important to connect underground metal piping, telephone systems, and electrical systems to the lightning protection system.
Lightning Arrestors ensures the safety of your electrical devices as it provides protection against the lightning, that enters the building via the electrical wiring system. For effective results, it is important to install the lightning arrestors either the interior service entrance or at the building’s exterior electrical service entrance.
Both lightning and voltage surges endanger people and their assets. About 1,500,000,000 lightning strikes every year, and the number is going up. Therefore, it is important to have an effective and efficient lightning protection system intact.
Implementation of lightning protection system requires artisanship and technological intuition. The industry has its own standards that need to be met to ensure a positive outcome. A well-designed, well-analyzed and well-implemented lightning system will make it possible to avoid casualties, injuries, and damages to a great extent.