What type of airflow systems ensure a continuous supply of oxygen for combustion?

Fresh Air Systems are designed specifically to introduce outside air into a building or structure, ensuring a continuous supply of oxygen necessary for combustion processes, such as those found in furnaces, boilers, and other heating equipment. By drawing in fresh air from the environment, these systems not only facilitate combustion but also help to maintain indoor air quality.

In contrast, exhaust air systems primarily focus on removing air from inside a building, which can lead to negative pressure if not balanced with sufficient fresh air intake. Return air systems recirculate indoor air, which may not contain enough oxygen for combustion without the contribution of fresh air. Ventilation systems, while they can include features to introduce fresh air and manage indoor air quality, do not specifically identify the function of supplying oxygen for combustion processes as the primary purpose of fresh air systems does.