Interlaboratory and proficiency tests for buildings sound insulation field measurements in Brazil - 4th Edition 2020

Since 2013 ABNT NBR 15575:2013 entered into force in Brazil, a national technical standard that establishes acoustic requirements for dwellings, that can be verified by means of field measurements procedures performed according to specific ISO standards. Therefore, those requirements have fostered the acoustic field measurement market, and the number of laboratories has quickly increased across the county. ProAcústica - Brazilian Association for Acoustical Quality, a non-profit entity, aiming to improve the quality of the acoustics business in Brazil has organized in 2020 the fourth edition of the "Interlaboratory program of field measurements for building acoustics laboratories - INTERLAB Program". This consists of a fundamental tool for acoustic field laboratories to evaluate and verify the quality of their measurement results. This paper presents the methodologies and procedures used in the interlaboratory program, as well as the results of both the interlaboratory test and the proficiency carried out in São Paulo (Brazil) during 2017 by ProAcústica - Brazilian Association for Acoustical Quality. In this edition a total number of 25 laboratories have participated (32% more participants than the last edition in 2017) for different type of field tests: airborne sound insulation, airborne facade sound insulation, impact sound level, sound pressure level from service equipment in buildings, and reverberation time). The main objectives are the evaluation of the precision of the field test methods in the Brazilian market, and the analysis of the performance of the participating laboratories as a quality control tool.