BS EN ISO 717-2:2020 pdf free.Acoustics一Rating of sound insulation in buildings and of building elements.Impact sound insulation. BS EN ISO 717-2 This document a) defines single-number quantities for impact sound insulation in buildings and of floors, b) gives rules for determining these quantities from the results of measurements carried out in one-third-octave bands in accordance with ISO 10140-3 and ISO...