How far must an air terminal extend above the protected object at minimum?

For effective lightning protection, an air terminal must extend a minimum distance above the protected object to ensure it can intercept lightning strikes and direct the energy safely into the grounding system. The minimum height requirement of 10 inches is essential because it provides sufficient clearance to protect a wider area around the structure. This extension enhances the air terminal's ability to create a zone of protection, making it less likely for lightning to strike the object itself.

In addition, a height of 10 inches is designed to account for variations in the surrounding environment that could influence the path of a lightning strike. This height forms part of well-established industry standards and codes, which guide the installation of lightning protection systems to ensure maximum safety and effectiveness. Thus, for the optimal protection of structures and to maintain compliance with these standards, air terminals must extend at least 10 inches above the objects they are meant to protect.