What is the minimum diameter for a solid copper air terminal for Class I?

The minimum diameter for a solid copper air terminal for Class I is specified as 3/8 inch. This size is important because it ensures that the air terminal can handle the high currents associated with lightning strikes without significant risk of melting or failure. Class I systems are meant for structures with higher exposure to lightning risk and require more robust components to ensure adequate protection.

Using a diameter of 3/8 inch provides the necessary conductive capacity and strength required to effectively carry the lightning energy safely away from the structure. Thicker terminals increase the surface area, reducing resistance and the likelihood of overheating. Adhering to specified sizes is crucial in lightning protection design as it guarantees that the system will function as intended during an actual event.