filtration efficiency

In this work we investigate the bidirectional filtration efficiencies of respirators, such as FFP2 masks and medical masks, under cyclic breathing and different fits. We developed a test bench, which consists of a test chamber with an artificial head, and which is connected to a specially developed artificial breathing function. The exhalation filtration performance of masks can be evaluated by exhaling particle-laden air into the test chamber. Similarly, the inhalation filtration performance can be evaluated by inhalation of particle-laden air from the test chamber.

Air handling units are used to provide a mixture of fresh and recycled (recirculated) air to buildings. They include general ventilation filters for the removal of particles and gases in order to protect the components of the air handling units and to provide clean air to occupants. Standardised test methods exist for the laboratory performance assessment of particulate filters - EN 779 (2012) in Europe and ANSI/ASHRAE Standard 52.2 (2007) in USA - and gas phase filters - ANSI/ASHRAE Standard 145.2 (2011) in USA and draft International Standard ISO/FDIS 10121-2 (2012).