Author(s): Mickaitis Marius, Jagniatinskis Aleksandras, Fiks Boris
Sound classification schemes (SCS) developed on national and international level gives possibility separate legal acoustics requirements for new, existing and renovated buildings. Among descriptors used to describe acoustic quality of rooms, reverberation time values are applicable for the different purpose buildings. Nowadays heritage buildings in the old city region go to be converted in conference rooms or a study purpose premises. Few auditoriums as well as classrooms in these renovated buildings were investigated to show importance of selected reverberation time indicator and its values for estimation acoustic quality of premises for communication and teaching. The first legal requirements for the reverberation time in Lithuanian legislation were introduced in 2004 by the SCS for buildings. Experience obtained during more than 10 Years’ of practical application of SCS for different purpose buildings shows necessity always to take in consideration possibilities of application of sound absorbing treatments. This should be taken into account already at the design stage and based on the different values of reverberation time indicators for the different frequencies. When SCS’s for buildings deals with the standardized single number rating for the noise and sound insulation descriptors, reverberation time still remain out of such harmonization. Analyzing of obtained results shows diversity of approaches to define reverberation time indicator. Additionally expanded frequency range indicates in general more strict requirements when values at the 250 Hz and sometime as well as at the 125 Hz octave band must be included in consideration. In this case applicable sounds absorbing construction should ensure enhanced absorption at low frequencies.
Name: Dr Marius Mickaitis