This document specifies test methods, test requirements and classifications for the casings of non-residential air handling units (AHU). The test methods and requirements are applicable to both complete units and any separate sections, except for the thermal and acoustic performance of the casing. The test method for the thermal performance of the casing is applicable for the comparison of different casing constructions, but not for the calculation of thermal losses through casing or the risk of condensation. The test method for the acoustic performance of the casing is applicable for the comparison of different constructions, but not for the provision of accurate acoustic data for specific units. This document is not applicable for fan-coil units and similar products. The filter bypass test specified in this document is not applicable to high efficiency particulate air filter (HEPA) installations.