Class I tubular air terminals must have an outside diameter of at least what measurement?

Class I tubular air terminals are an essential component in lightning protection systems, designed to intercept lightning strikes and safely direct the energy to the ground. The specification for the minimum outside diameter of these terminals is crucial for their effectiveness and structural integrity.

The requirement for an outside diameter of at least 1/2 inch ensures that the terminal can adequately handle the high currents associated with a lightning strike. A larger diameter improves the terminal's ability to dissipate energy and reduces the risk of melting or deformation during a lightning event. It also plays a role in ensuring that the terminal will not easily become damaged due to environmental factors or external forces.

This particular diameter standard is rooted in safety and reliability, as it establishes a baseline for performance in the often challenging conditions that lightning protection systems must endure.

Among the other choices, while they may relate to various applications or types of air terminals, they do not meet the minimum requirement specified for Class I tubular air terminals, highlighting the importance of adhering strictly to established guidelines in lightning protection technology.