For air terminals positioned over 24 inches in height, what must be done?

For air terminals positioned over 24 inches in height, bracing is necessary to ensure their stability and effectiveness in the lightning protection system. Air terminals, often referred to as lightning rods, need to remain upright and secure, especially when they are elevated. This bracing acts as a support mechanism that prevents swaying or bending that could occur due to wind, environmental factors, or even the forces generated during a lightning strike.

When air terminals are properly braced, it enhances their reliability, ensuring that they serve their purpose of attracting and safely conducting lightning down to the grounding system. Such measures are critical in maintaining the integrity of a lightning protection system and ensuring safety during storm conditions.

The other options do not specifically address the need for stability and support of elevated air terminals; while grounding is always necessary for a complete lightning protection system, it is not a specific requirement for air terminals over that height. Painting, while it may have aesthetic or corrosion resistance purposes, does not relate to the structural support needed for taller terminals. Finally, while additional downleads can play a role in lightning protection, they do not substitute for the stability provided through proper bracing.