Filters for gaseous contaminants: performance measurement and impact on ventilation systems.

Filters for gaseous contaminants which are used inside HVAC systems are characterised by means of rated air flow rate, air motion resistance, trend of the mass efficiency versus time and holding capacity of the considered gas. The determination of the characteristics cannot do without the use of experimental activities, even though many aspects seem to be foreseeable through calculation models based on general laws. A test rig for granular media which uses toluene in small concentrations in the air is presented here.