This document specifies laboratory methods for measuring the impact sound insulation of floor assemblies. The test results can be used to compare the sound insulation properties of building elements, classify elements according to their sound insulation capabilities, help design building products which require certain acoustic properties and estimate the in situ performance in complete buildings. The measurements are performed in laboratory test facilities in which sound transmission via flanking paths is suppressed. The results of measurements made in accordance with this document are not applicable directly to the field situation without accounting for other factors affecting sound insulation, such as flanking transmission, boundary conditions, and loss factor. A test method is specified that uses the standard tapping machine (see ISO 10140-5:2021, Annex E) to simulate impact sources like human footsteps when a person is wearing shoes. Alternative test methods, using a modified tapping machine or a heavy/soft impact source (see ISO 10140-5:2021, Annex F) to simulate impact sources with strong low frequency components, such as human footsteps (bare feet) or children jumping, are also specified. This document is applicable to all types of floors (whether heavyweight or lightweight) with all types of floor coverings. The test methods apply only to laboratory measurements.