When designing a building in a noisy environment the answer is often to design the building with windows closed and mechanical ventilation.
However, perversely noise can be created from the ventilation systems if not designed appropriately. To ensure the ventilation system does not create unwanted noise levels the system should be designed to ensure the fans are the correct size and speed and the duct runs do not generate an increase on sound. It is also possible to specify sound absorption properties within the systems such as silencers.
Direct noise can be generated from the ventilation system through fan and aerodynamic noise. Indirect noise from outside the ventilation system can also travel through the ventilation system.
Where possible ventilation inlets should be located on the elevation away from the noise source to ensure a lower level of noise transmitted. Windows and walls with acoustic trickle vents can be specified to provide an increased level of external noise attenuation.