Air Systems Cleaning Specialist (ASCS) Practice Exam

The best type of fan for air transport in long duct runs is a centrifugal fan. This is because centrifugal fans are designed to efficiently move air through long distances while overcoming resistance created by ductwork. They operate by converting rotational energy, typically from a motor, into airflow, which allows them to generate higher pressures than axial fans.

In a lengthy duct system, the ability to maintain airflow and pressure is crucial, and centrifugal fans excel in applications requiring these attributes. Their design allows for a uniform airflow distribution and helps mitigate pressure losses that can occur over extended duct lengths. Additionally, centrifugal fans are well-suited for systems that require handling particulate-laden air, as their construction allows for effective performance without significant loss of efficiency over those longer runs.

While axial fans are effective for shorter distances and specific applications, they lack the pressure capability needed for longer ducts. Radial fans typically refer to a design similar to centrifugal fans but often lack the specific efficiency profiles needed for great pressure. Forward-curved fans, while efficient for moving air, can be less effective in high-resistance systems compared to centrifugal fans, especially over longer distances.