Interlaboratory and proficiency tests for building's sound insulation field measurements in Brazil - 6th Edition 2024

Since the implementation of ABNT NBR 15.575, which establishes acoustic performance requirements for residential buildings, the demand for sound insulation testing has grown significantly in Brazil, leading to an increase in acoustic field measurement laboratories. To support this development, ProAcústica - Brazilian Association for Acoustical Quality, a non-profit organization, has been organizing the Interlaboratory and Proficiency Program of Field Measurements for Building Acoustics Laboratories - INTERLAB Program. In 2024, the sixth edition of the INTERLAB Program was conducted in São Paulo, Brazil, with the participation of 34 laboratories. The program included tests on airborne sound insulation, facade sound insulation, impact sound level, sound pressure level from service equipment in buildings, reverberation time, sound pressure level in inhabited areas, and sound pressure level in indoor environments. This paper presents the methodologies, procedures, and results of the 2024 edition of ProAcústica's Interlaboratory and Proficiency Program, as well as a comparison with previous editions. The main objectives were to evaluate the accuracy of field test methods in the Brazilian market, analyze the performance of participating laboratories, and reinforce quality control in building acoustics testing.