Abstract: A vent assembly has a vent housing having a first axial end, a second axial end, and an airflow pathway extending from the first end towards the second end. An environmental opening is towards the second axial end for fluid communication with an external environment. An enclosure opening is towards the first axial end for fluid communication with an interior of an enclosure. A perimetric support surface surrounds the airflow pathway. A support brace extends across the airflow pathway. The support brace has a lateral support surface offset in the axial direction from at least a portion of the perimetric support surface. Filter media is disposed laterally across the airflow pathway. The filter media has a perimeter region supported by the perimetric support surface around the airflow pathway and a central region supported by the lateral support surface such that the filter media is non-planar.

Abstract: A vent assembly has a vent housing having a first axial end, a second axial end, and an airflow pathway extending between the first axial end and the second axial end. An environmental opening is towards the second axial end configured for fluid communication between an outside environment and an airflow pathway. An enclosure opening is configured to selectively define a fluid flow pathway between an interior of an enclosure and the airflow pathway. The vent assembly has an obstruction having a first relative position and a second relative position. The obstruction is configured to obstruct the fluid flow pathway in the first relative position and unobstruct the fluid flow pathway in the second relative position. Filter media is disposed in the vent housing laterally across the airflow pathway.