Continuous or intermittent noise from an insufficiently designed HVAC system is disruptive and distracting. In many instances design professionals focus on delivering the proper airflow, but ignore acoustical aspects, often assuming that white noise from mechanical systems is beneficial because it helps mask other noises within the work environment.

A noise reduction/abatement program is essential for many industries, especially manufacturing facilities, because of safety and potential claims for hearing damage. In offices, acoustic problems are both a leading source of employee dissatisfaction and the least addressed in office designs (General Services Administration (GSA) workplace research (Sound Matters, January 2012)). Today, owners, designers, developers and insurers of all building types are increasingly aware that HVAC noise can contribute to litigious health issues for both occupants and neighbors. Addressing the acoustical aspects of air handling systems is equally critical as meeting air flow heating and cooling design requirements.

In order to analyze, evaluate and remedy—if necessary—HVAC acoustic issues, several steps are necessary. The first is to analyze the entire duct system. This begins by evaluating the natural attenuation that occurs in HVAC systems. If undesired sound persists despite natural attenuation efficient and cost effective acoustical remedies need to be specified. Leading noise control product manufacturers offer no-cost design and engineering assistance in analyzing duct systems (see example of a web-based program below), but it behooves design professionals to have an understanding of the concepts underlying HVAC noise control. Such an understanding will also help during the design phase when natural attenuation strategies can easily be incorporated.

Sound attenuators for HVAC systems Photos courtesy of Kinetics Noise Control, Inc.