Class A unidirectional flow hood  (UFH), also called Laminar flow hood  (LAF) is a type of air purifying equipment providing Class A unidirectional flow and thus creating a highly clean environment.

UFH is used for the protection of the filling/packaging operations of products that are sensitive to contamination, may be used separately or in combination. It can be designed to have an independent air return system or to connect with the current duct.