Provides: a) single-number quantities for impact sound insulation in buildings and of floors; b) 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 140-7, and in octave bands in accordance with that option in ISO 140-7 for field measurements only; c) single-number quantities for the impact sound reduction of floor coverings and floating floors calculated from the results of measurements carried out in accordance with ISO 10140-3; d) a procedure for evaluating the weighted reduction in impact sound pressure level by floor coverings on lightweight floors.