Lightning is certainly fascinating, and maybe a bit scary. We know there are precautions to take when you're outside and lightning is detected, but how do we protect our buildings?
Engineering Lightning Protection Systems
According to the Lightning Protection Institute, the lightning protection industry began in the United States when Benjamin Franklin suggested that lightning was electricity, and a metal rod could be used to carry lightning away from a building. Direct lightning strikes cause fire damage in excess of $200 million per year, and insurance companies pay claims in the billions of dollars associated with lightning either directly or indirectly. Most of these property losses could be minimized, if not eliminated, through the implementation of proper lightning protection for structures.
How is lightning protection engineered into buildings?
From the time Benjamin Franklin used the sharp metal steeple of a church in Pennsylvania, to today’s engineered installations, lightning protection systems have been safeguarding buildings. But what exactly is lightning protection?
Lightning protection is simply a way to route the energy from a lightning strike safely to ground in a controlled manner. The goal is to give the lightning a low resistance path, minimizing the chances of electrocution and fire.
Most people associate lightning protection with the air terminals or “lightning rods” visible on top of buildings and other structures. While these are a vital part of a protection system, they are only a piece of the solution.
A lightning protection system must have a grounding system, usually consisting of:
- metal rods,
- metal grids or mesh,
- and/or metal plates,
- installed in the earth, and
- connected to each other with metal conductors.
The air terminals need to be connected to one another, and then connected to the grounding system by metal conductors. These conductors can be exposed or hidden in the construction of the building.
As simple as the components are, the engineering behind installing systems can be complicated. It generally starts with a risk assessment to determine if a system should be installed.
The system is then designed based on the building’s:
- roof type and slope
- distance to other structures and
- additional items such as:
- mechanical equipment
- flag poles
Soil conditions may also need to be evaluated for proper grounding of the system. Lightning protection designers typically use software designed to take all of these factors into consideration to produce a code-compliant design.
Design with Purpose. Build with Confidence.
Schemmer is a full-service architecture, engineering and construction field services consultant, providing responsible solutions for complex design and construction-related challenges. Founded in 1959, we are grounded in our past but remain fully committed to the future. Located in three States and six offices throughout the Midwest, Schemmer is providing services to clients from coast-to-coast and border-to-border across the United States.
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