One-way sound insulation

 

Installations in the void between the structural soffit and the suspended ceiling, such as piping and ductwork systems, can give rise to noise. In such cases, a sound insulating suspended ceiling system can be used to reduce the noise to acceptable levels in the room below.

One-way sound insulation values 

Laboratory value R_w according to ISO 140-3 and ISO 717-1

In order to determine the noise level generated by a source in the void, you should ascertain the frequency spectra of the suspended ceiling's sound insulation and the noise source.