room noise

[shameem]

Hi
We just complete a HVAC project.After running the AHU we find a major problems that in few room due to air flow it creating very high level of noise.I thing it is because of very high safety static pressure in the duct, Is there any way to reduce the level of noise in the duct,We used silencer in the duct line,Is there any other reasons which can create sound in the room.

[icecube51]

did you check the speed and volume of the air passing the AHU??

ice

[shameem]

Yes i checked.it was 5000m3/h,and SP is 2000Pa

[nike123]

What is air speed on grilles?

[solas]

Hello

Airborne noise can be generated in ductwork systems
as a result of excessive air velcoities.

If noise is emitted from the distribution ductwork, and the duct air velocity exceeds the recommended maximum levels, you could have a major problem.

You could consider the following options;
1. lag the duct with acoustic insulation - however retrofitting acoustic insulation has a limited effect.

2. integrate acoustic insulation with ceiling system-it should help dampen breakout noise.

3. measure the air flow rate at duct sections that are audible from within the occupied space - check measured air volumes against design and commissioning data, reduce if possible.

If problem noise is occuring at the supply air terminal's, measure the face velocity.
Typically, the maximum recommended face velocity for louvre faced diffucers, serving general open plan office area should not exceed c. 2.5m/s -so as to satisfy best practice room noise levels.

Rather me than you.