Mitigating industrial noise in existing facilities presents significant challenges, particularly when they were not designed to accommodate noise mitigation measures. These measures often involve spatial and/or operational modifications, which can be particularly difficult to implement on existing equipment. Moreover, when the role of the acoustician is limited to evaluating mitigation options while the client is responsible for the bidding and installation of those measures, there is a risk of misinterpretation of the purpose and scope of the acoustician's intervention. In this case, acousticians were involved in the design of a silencer for a large fan, for which noise levels emissions in the environment had to be controlled. However, the design team was not involved in the tendering process, and the silencer that was provided performed well beyond the design requirements, resulting in significantly more restrictive conditions and higher-pressure losses. During commissioning, noise measurements revealed that sound levels at the chimney outlet exceeded the fan sound level. This paper presents a detailed account of the investigations, CFD modeling, and custom modifications to the silencer that were undertaken to address this issue and reduce noise emissions.
Loic Sauvageot (2025) studied this question.