Are there air flow variations in a filter system?
There can be if not accounted for in design and system balancing. There are three components of flow variation in a filter system: (1) filter-to-filter variations due to manufactured differences in filter flow resistance (pressure drop), (2) variations in the position of a filter element in a filter housing (front-to-back variations), and (3) variations in the position of a filter housing due to its location in a filter bank (side-to-side variations). It is important to minimize variations to ensure that air does not preferentially flow through one or more filter housings, effectively creating “hot spots” where the actual flow rate would exceed design objectives.
