This European Standard describes the methodologies to be used in a laboratory air tight chamber to test prototype or commercial air cleaner systems with a maximum flow rate of 1,000 m3/h used for photocatalytic indoor air remediation. It is applicable to the treatment of atmospheres that are representative of the air inside buildings and workplaces. This protocol is applicable solely to photocatalytic systems alone or to combined systems that include a photocatalytic function. The photocatalytic function is demonstrated by verifying the mineralization of model VOCs to form CO2.