A pilot study on the use of the heavy/soft impact source for building acoustic impact measurements in housing

Most countries in Europe have building regulations, which include limit values for acoustic qualities for housing, including airborne and impact sound insulation between dwellings. An overview of such requirements in 35 countries in Europe is found in [1], and limits are field values with reference to ISO 16283 [2] and ISO 717 [3]. For impact sound, the source is the tapping machine. However, the rubber ball has recently – initiated by Korea and Japan – been implemented in ISO standards as an additional impact source, cf. ISO 16283 and ISO 717 as well as the laboratory methods in ISO 10140 [4]. Outside Europe, the tapping machine is also the most well-known impact source in relation limits for housing.
Several acoustic classification schemes exist in Europe with acoustic quality classes for the same performance areas and methods, see [1] and [5], and an international classification method for housing has been defined in ISO/TS 19488:2021 [6], being prepared in ISO/TC 43/SC 2/WG29. The ISO/WG currently discusses revisions of ISO/TS 19488. Korea and Japan want the impact ball method included in ISO/TS 19488, since their experiences show better simulation with sounds from jumping children, which is a major source of annoyance worldwide, also in Europe. In Denmark, neighbour noise also annoys many people, see [7] and [8], and especially in housing with old light-weight timber floors.
This paper deals with sound insulation of floor constructions between dwellings with focus on impact sound, including results from a pilot study with both the tapping machine and the rubber ball as impact sources. The pilot study became possible due to interest in cooperation from two BSc students [9] making a bachelor thesis at DTU about laboratory tests of a typical, old Danish light-weight timber floor and potential for improvements of sound insulation. Due to constraints in the BSc thesis time period and availability of lab facilities, we had limited options for tests, but nevertheless we succeeded to get insight in the challenges, when trying out the new alternative test with the rubberball as the impact source.