period four
Equipment Sound Rating
notes
Rating HVAC Equipment
Figure 59
HVAC Equipment Sound Rating
As mentioned earlier, because sound pressure is influenced by the surroundings, often the best way for an equipment manufacturer to provide sound data is to provide sound-power levels.
Sound-power levels for many types of HVAC equipment are determined in an acoustics laboratory, usually by the manufacturer. Sound-power levels are determined by measuring sound-pressure levels in a test facility with known acoustical characteristics, and adding back any environmental effects attributed to the surroundings. Formal written standards qualify such test facilities and methods, in order to promote uniformity of data between different manufacturers across the industry. This allows for objective comparisons of similar equipment.
The two most common methods of determining the sound power of HVAC equipment are the reverberant-room and free-field methods.
