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The Acoustic Properties of Common HVAC Plena.

The Acoustic Properties of Common HVAC Plena.

Authors :
Mouratidis, Emanuel
Becker, John
Source :
ASHRAE Transactions. 2004, Vol. 110 Issue 2, p597-606. 10p.
Publication Year :
2004

Abstract

The HVAC plenum is commonly applied as a means to reduce problematic low-frequency noise produced by mechanical equipment in ducted systems. The predicted acoustical performance has been derived from an earlier investigation (Wells 1958). This early work did not focus on low-frequency performance, the effects of wall linings, or typical geometric variables. Through the ASHRAE-sponsored research project RP-1026, conducted by Vibro-Acoustics®, rigorous testing enabled the identification of comprehensive attenuation properties for common HVAC plena. A two-stage prediction approach resulted, which applies an improved version of the Wells equation for mid- to high-frequency attenuation (5000 Hz upper frequency limit), quantified as a transmission loss (TL), and a surface area and wall characteristic model for the critical low-frequency TL (50 Hz lower frequency limit). This method has improved the prediction accuracy of flow-through type HVAC plena with a volume range of 20-1100 ft³ (0.5-30 m³). In addition, this work has identified acoustical effects for seven different wall-lining systems and typical geometric variables, such as opening offsets, opening ratio variables, and multiple openings. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00012505
Volume :
110
Issue :
2
Database :
Academic Search Index
Journal :
ASHRAE Transactions
Publication Type :
Conference
Accession number :
15565164