Case Study: Community Noise Annoyance Mitigation with Intake/Exhaust Silencer Redesign
An evaluation of community noise annoyance was commissioned to identify the causes of complaints from residents living nearby and to develop potential modifications for mitigation. Elevated pulsation levels were identified at frequencies below the range of the human ear, but were the most likely cause of rattling window panes, doors, cabinets, etc. The sources of the pulsations were traced to pressure pulsations associated with engine inlet and exhaust manifolds at the nearby compressor station. Field measurements identified the pulsation characteristics at the residences and within the manifolds. Field measurements also provided data for correlation with an acoustic model. It was determined that the existing systems did not significantly attenuate low frequency pulsations, which allowed transmission of those pulsations into the atmosphere. Predicted intake and exhaust resonances correlated with the elevated frequencies measured at the residences. New silencers were designed to reduce the low frequency pulsations produced by the engines. This paper will describe the field measurements used to diagnose the problem and identify the source; a pulsation analysis and silencer redesign; and follow up field measurements to assess the quality of the redesign.