@article {Marshall:2024:0736-2935:1092,
title = "Low-frequency HVAC 'rumble' in a high-end condominium",
journal = "INTER-NOISE and NOISE-CON Congress and Conference Proceedings",
parent_itemid = "infobike://ince/incecp",
publishercode ="ince",
year = "2024",
volume = "269",
number = "1",
publication date ="2024-07-14T00:00:00",
pages = "1092-1097",
itemtype = "ARTICLE",
issn = "0736-2935",
url = "https://ince.publisher.ingentaconnect.com/content/ince/incecp/2024/00000269/00000001/art00011",
doi = "doi:10.3397/NC_2024_0146",
author = "Marshall, Steven E.",
abstract = "Sound and vibration measurements were conducted at a high-end condominium located in downtown Washington DC. Data was collected within the clients residence unit and on the buildings roof. The objective for the measurements was to identify and characterize the sound
within the unit for which the resident had complained. The source of the sound in the bedroom was identified from vibration on a wall adjacent to an HVAC vertical duct. The sound and vibration were found to originate at a roof-mounted fan integral to the HVAC air distribution system. The character
of the sound was modulating, low-frequency rumble. Further investigation on the roof, however, revealed the buildings structure to be adequately isolated from vibration due to the fan and motor. Rather, the sound was generated by the interaction of the fans aerodynamics
and the acoustical properties of the vertical duct. The amplitude of the acoustic field in the duct was sufficient to excite vibration of the ducts enclosing walls. Instead of modifying the structural geometry of the vertical duct, the most efficient fix to attenuate duct
rumble was by installing a silencer in the horizontal duct between the exhaust fan and the vertical duct.",
}