Which of the following statements is correct regarding the termination heights of chimneys?

The statement that chimneys should be at least 3 feet above the roof's highest point is correct because it is based on established building codes and best practices regarding chimney design and safety. This requirement ensures that chimneys have adequate height to disperse exhaust gases effectively and minimize the risk of downdrafts, which can lead to potentially hazardous conditions.

By having the chimney extend at least 3 feet above the highest point of the roof, it helps to improve draft performance and reduce the possibility of smoke or harmful gases entering the living space. Additionally, this height requirement can help mitigate any obstruction that nearby structures or trees might cause, ensuring the safe and efficient operation of the chimney.

While it is true that national codes provide a general guideline, local building codes can vary based on specific needs or environmental considerations, but they typically align with that minimum height requirement.