In a HVAC system, the potential noise sources are AHU, terminal units and room air outlets. The sound wave generated by these sources transfer its energy throughout the duct and to the occupant’s area; Sound Power and Sound Pressure are different in that Sound Power is a measure of total energy per unit time emitted by the source in all directions. Sound pressure is a measure of pressure variation at the receiver’s location.
Noise Criteria (NC) is a single number rating derived from sound pressure levels in all eight octave bands, and is intended to predict an occupant’s response to the overall sound level. The critical octave bands for evaluating sound performance ranges from 63 to 8000 Hz.
Silencer Splitter is constructed of solid and perforated metal that is located inside the silencer which protrudes into the air stream and house the acoustic media.
Air gap is a gap between two splitters, standard available gaps are 75,100,125,150,175 & 200mm. selected to meet the required NC level.
Bull nose is constructed as round convex shape on both side of the splitter to provide smooth airflow and to ensure maximum insertion loss and minimal pressure drop.
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