Acoustic activities at CSTB in the 20th century

This paper is about the history of the acoustic activities at CSTB, French Center for building Science and Technology. It is an improved and extended version of a paper presented in a structured session on the history of acoustic activities in Europe, at Forum Acusticum 2023 in Torino, Italy. The CSTB Acoustic Department was created in the 1960s around an acoustic test laboratory. From the beginning CSTB has been involved in improving acoustic performance for building occupants. It played an important role in technically supporting the French acoustic regulation (first one in 1968 and last one in 1995) and in developing solutions to reach mandatory building performances in cooperation with the industry. The acoustic department grew fast, mainly supported financially by the government (more than 60% of its budget at the beginning), thus becoming the largest acoustic team in France and worked on 3 main domains: room acoustics, environmental acoustics and building acoustics, in which physical models and calculation tools have been developed to bring science to construction. From the start, CSTB has been involved in standardization at French, European and International levels.