An attenuator for buildings using natural ventilation

This paper concerns the development of a commercial noise attenuation device for buildings that rely on natural ventilation as the primary method of ventilation, or in conjunction with air conditioning systems to provide fresh air intake. The present design of the device is the culmination of research done over the past five years to provide natural ventilation of buildings while satisfying internal noise level requirements. The current device is designed to fit into existing fixed air vents in residential buildings or as a module which can be installed in an array in buildings where significant air movement is required and thermal comfort is of high priority. Results from insertion loss measurements are presented, indicating that the device provides up to 25dB insertion loss in a third octave band within the range of frequencies to which the resonator tubes are tuned. An overall A-weighted reduction of up to 16dB was achieved, indicating that the device provides an additional 16dB A-weighted reduction of noise over the standard reduction provided by traditional fixed air vents. (C) 2001 Institute of Noise Control Engineering.