Assessment of the low-frequency procedure in the field measurements of impact sound insulation between dwellings

In 2015, the new standard ISO 16283–2 for field measurements of impact sound insulation introduced a low-frequency procedure (LF-procedure) for measuring impact sound pressure levels and reverberation times at 1/3-octave bands below 100 Hz. The LF-procedure is followed when the volume of the receiving room is smaller than 25 m3. The LF-procedure is based on studies concerning field measurements of airborne sound insulation. Its aim is to improve measurement uncertainty of low-frequency sound insulation measurements. The procedure has not been assessed for use with impact sound insulation measurements. The objective of this study was to assess the standardized LF-procedure in the field measurements of impact sound insulation. The results show that the measurement uncertainty is improved. However, the impact sound pressure levels raise 4 dB on average. The values of L′n,w + CI,50-2500 and L′nT,w + CI,50-2500 also increase from 2 dB to 7 dB in most cases.