What is the primary function of a natural draft system?

The primary function of a natural draft system is to rely on natural air movements for venting. This system operates based on buoyancy, where warmer, lighter gases rise and create a draft that allows fresh air to enter the system. The principle takes advantage of the temperature differences between the exhaust gases and the outside air, causing the exhaust to flow upwards through chimneys or vents without the need for mechanical assistance.

Natural draft systems are commonly found in traditional heating appliances such as gas furnaces and water heaters. Their effectiveness depends on the design of the venting system, including factors such as height, diameter, and the presence of any obstructions. This reliance on natural airflow makes them energy-efficient, as they do not consume additional energy to operate mechanical fans or blowers for venting.

Understanding this principle is crucial in gas safety and appliance installation, as improper venting can lead to hazardous situations, such as backdrafting, where harmful gases may enter living spaces.