Practical experience in verification acoustic class for building in octave versus one-third octave frequency bands

Abstract

Among ten national schemes developed in EU for the sound classification of buildings, today only five is linked to the building code (regulatory requirements). Background in discussions about advantages of classification schemes is a relationship between subjective perception of acoustics comfort in premises and objective evaluation of the selected acoustic descriptors. Available consensus on selected indicators and appropriate limit values additionally should be expanded on procedures for verification of compliance with an acoustic class. In Lithuania developed sound classification scheme since 2007 year was enforced by mandatory pre-completing testing for new and renovated buildings. In the conformity assessment one of the more controversial aspects becomes selection of the appropriate standards provisions for field testing code. All criteria of the expected class in questions may be assessed applying procedures provided in series standards ISO 16283, ISO 10052 and ISO 717. From the point of economic implications for testing there is possibilities to carry out testing’s in one third octave and alternatively in octave bands. Presented result of comparison measurements for a sound classification of a few new buildings in Lithuania shows possibilities select the octave band measurements only. Additionally this investigation allows justify the application in generally the standard ISO 10052 for verification of entire building. In such approach survey method becomes a general and application of engineering method from series standards ISO 16283 remain for doubt cases when individual results deviates from criteria adversely by more than 1 dB.