What is an attenuator on ductwork?
What is an attenuator on ductwork?
A sound attenuator, or duct silencer, sound trap, or muffler, is a noise control acoustical treatment of Heating Ventilating and Air-Conditioning (HVAC) ductwork designed to reduce transmission of noise through the ductwork, either from equipment into occupied spaces in a building, or between occupied spaces.
Do attenuators reduce noise?
Duct attenuators, also called silencers, are used to reduce noise radiated from the inlet and the outlet of fans and other air handling equipment.
Where should a duct silencer be placed?
In most cases, air duct noise silencers are mounted between the fan and the exhaust fan as well as before the air diffusers and should be installed behind fans.
How do you select sound attenuator?
The first step in selecting a suitable attenuator configuration is to choose a model that meets the required insertion loss. This will determine the length and module width of attenuator. The next step is to determine the width and height of the attenuator. The height can be selected to suit the application.
What is audio attenuation?
Acoustic attenuation is a measure of the energy loss of sound propagation in media. Most media have viscosity and are therefore not ideal media. When sound propagates in such media, there is always thermal consumption of energy caused by viscosity.
How much does a duct silencer cost?
Rectangular Air Duct Mufflers/Silencers
Item # | List Price | Width |
---|---|---|
Duct Muffler-08×08 | $78.00 | 8 in |
Duct Muffler-08×10 | $84.50 | 10 in |
Duct Muffler-08×12 | $91.00 | 12 in |
Duct Muffler-08×14 | $97.50 | 14 in |
How does HVAC silencer work?
Most types of HVAC silencers contain baffles—acoustic media made up of millions of air pockets. When sound waves hit these air pockets, the molecules are bashed together and the energy is turned from sound to heat. This effectively reduces noise but also creates a pressure drop in the airflow.
How do you size a silencer?
Silencer Capacity based on Inlet CFM 14.7 PSIA at 70°F
Size | INLET SILENCER | DISCHARGE SIL. 15 psig |
---|---|---|
8 | 1,920 | 2,940 |
10 | 3,000 | 4,590 |
12 | 4,300 | 6,600 |
14 | 5,900 | 8,990 |
What is static insertion loss?
A static insertion loss is the insertion loss with no air flow passing through the attenuator. Therefore placing an attenuator in between a fan and the measuring position, will reduce the noise level at the measuring position by the insertion loss.
Why is attenuation important?
The importance of attenuation Attenuation is important in telecommunications and ultrasound applications because it’s critical to determining signal strength as a function of distance.
What causes sound attenuation?
There are four mechanisms that cause sound energy to be absorbed and sound waves to be attenuated as they propagate in a single-component, homogeneous fluid: Viscous (shear) effects in bulk fluids. Thermal conduction in bulk fluids. Molecular absorption in bulk fluids.