ACOUSTICAL CHARACTERIZATION OF PORTUGUESE LIBRARIES

This paper presents the acoustical characterization of the main reading room of 28 public li-braries in Portugal. In situ measurements were held regarding the interior sound pressure lev-els (background noise, with and without the HVAC equipment working), the Noise Criteria and Noise Rating values (NC/NR), the objective speech intelligibility using the Rapid Speech Transmission Index (RASTI) and Reverberation Time (125 to 4k Hz). Two groups of librar-ies were formed (Classic and Modern libraries) regarding their interior layout and date of construction and differences were checked. Regression models among the architectural and acoustical parameters were established. The acoustical performance of these spaces concern-ing the current Portuguese legislation is analyzed and a short set of design goals are presented to help acoustical consultants to achieve a good environment in this type of building. 1