Which type of filter is likely to create the highest static pressure drop?

The correct answer highlights a pleated fiberglass filter as likely to create the highest static pressure drop. Pleated filters are designed to increase the surface area available for capturing particles from the air. However, the increased surface area also means that they can have a denser structure compared to other types of filters, which can lead to a higher static pressure drop.

While activated carbon filters are effective at removing odors and some chemical vapors, their structure is generally less dense, resulting in a lower resistance to airflow. HEPA filters, known for their high efficiency in trapping very small particles, can also create significant static pressure when new due to their dense mat of fibers. However, in comparison, pleated fiberglass filters typically have a high resistance to airflow as they are designed primarily for capturing a wide range of particulates.

Washable filters, although they can vary in construction, are often made to allow easy airflow. This makes them less likely to create high static pressure drops when compared to pleated fiberglass filters. Overall, pleated fiberglass filters offer a balance of efficiency and particle capture capability while also presenting more airflow resistance, leading to a higher static pressure drop in the system.