A chimney must extend at least how many feet above the highest connected equipment draft hood outlet?

The correct answer indicates that a chimney must extend at least 5 feet above the highest connected equipment draft hood outlet to ensure proper venting and combustion efficiency. This specific height is crucial in allowing for adequate draft, which helps to safely exhaust combustion gases away from the appliance and prevent backdrafts that could lead to dangerous situations, such as carbon monoxide buildup.

Extending the chimney to this height also helps to mitigate the effects of wind, which can create pressure changes around the chimney that might interfere with the draft. Establishing the proper height contributes to the overall safety and performance of the heating system, ensuring that exhaust gases are effectively and safely vented.

The incorrect choices suggest lower heights, which do not meet the necessary standards for safe ventilation. Choosing a height insufficient for effective drafting could compromise the system's efficiency and potentially lead to hazardous conditions.