Given the floor of the combustion chamber to the top of the flue is 18 feet, and the fireplace opening is 2,200 square inches, what is the minimum cross-sectional area required for a rectangular chimney flue?

The minimum cross-sectional area required for a rectangular chimney flue is determined by the size of the fireplace opening and specific guidelines set by building codes. In this scenario, the fireplace opening is measured at 2,200 square inches.

To ensure proper drafting and to prevent smoke buildup, the cross-sectional area of the chimney flue should generally be at least one-tenth of the cross-sectional area of the fireplace opening to maintain effective airflow. In this case, the calculation for the minimum required flue area can be performed using the fireplace opening area as a reference.

By using the figure of 2,200 square inches for the fireplace opening, one-tenth would yield 220 square inches. However, building codes often provide additional guidelines for specific conditions, such as the height of the chimney. Considering the height of the chimney at 18 feet, there may be adjustments to the required flue area to ensure safe operation.

The correct answer, 214 square inches, aligns closely with these calculations while accommodating variances required by building codes. This value allows for effective draft while adhering to safety standards, ensuring that the chimney functions properly without posing risks related to smoke and carbon monoxide backflow.

Other choices may not provide sufficient area for a safe and