Chimney Safety Institute of America (CSIA) Certification Practice Test

For residential solid-fuel appliances, the cross sectional area of the flue shall not be _____ than that of the appliance flue collar.

1. Greater than

2. Less than

3. Equal to

4. More than

The correct answer is: Less than

The cross-sectional area of the flue for residential solid-fuel appliances must not be less than that of the appliance flue collar to ensure proper drafting and efficient operation. If the flue's cross-sectional area is smaller than the flue collar, it can restrict airflow, leading to inadequate ventilation of combustion gases. This situation can create several hazards, including poor draft that may cause smoke to back up into the living space, potential buildup of dangerous gases like carbon monoxide, and increased creosote formation, which elevates the risk of chimney fires. Proper sizing of the flue is crucial for the safe and effective functioning of solid-fuel appliances, thereby supporting optimal combustion and minimizing the risk of safety issues.