The protection zone of a lightning rod can be determined using the "rolling sphere method" and the "broken-line method." The broken-line method is straightforward to design and economical to implement, though it is unsuitable for very tall buildings. In contrast, the rolling sphere method-which relies on computational modeling to define the protection zone-is highly complex and entails significant costs.
Comparing the two, the rolling sphere method is considered the more sophisticated and reliable approach. It involves simulating a sphere rolling around the building; areas within the sphere's path that remain untouched by the sphere itself constitute the "safe zone"-essentially the area beyond the reach of a lightning strike. However, lightning rods have inherent limitations regarding their coverage area, which explains why multiple rods are often installed on a single building.
Generally, the higher the installation point and the greater the number of lightning rods, the more effective the protection for the building. Modern advancements have transformed lightning protection into safer, more practical systems. One such system is the "concealed cage-type lightning protection network," which interconnects the building's metal components to form a massive metallic mesh. This network offers excellent shielding, is convenient to install, and enhances the building's aesthetics; furthermore, it functions effectively as a down-conductor to channel lightning current safely into the ground, ensuring a high level of safety.