“Ariosto” Project – Noise Mitigation Works for Technological Systems

This study was carried out on the air conditioning systems installed on the top of the building of the IT Department of the Faculty of Engineering of “La Sapienza” University in Rome.

The first phase regarded the feasibility study, for which SoundPlan Open-field 3D acoustic modelling noise simulation software was used.

Subsequently, once the noise mitigation objectives and the solutions to be adopted were identified, an executive project was drafted designed to define in full all the works necessary for the engineering of the appropriate technical solution.

The project was drawn up taking account of the following criteria:

• head losses compatible with the functioning of the systems
• clear separation of incoming and outgoing air flows
• acoustic reflections present
• reduced level of residual noise (with systems turned off)
• position of the most exposed receiver
• exposure to the exterior of the buildings
• inspectability of the systems
• structural modifications necessary to support the noise mitigation works

Acoustic study

The project comprised the following:

1. Consolidation of the support structure of the machinery
2. Construction and installation of silencers around the air exhaust fans of the refrigeration units
3. Construction and installation around the perimeter of the machines of sound-insulating and sound-absorbing vertical panels
4. Construction and installation of baffle silencers for the treatment of the refrigeration unit air intake section
5. Installation of a structure with hot-dip galvanised steel profiles to support the vertical panels, as described in the structural reports.
6. Cladding with sound-insulating/sound-absorbing elements to “seal” the bottom of the barrier perimeter, to be verified on-site

The work described is guaranteed to remove “visibility” between the direct sound emitted by the sources and all the receivers potentially disturbed by the technological systems considered.

The purpose of the silencers on the exhaust fans is to reduce the noise of the fans, while the sound-absorbing baffles positioned at the sides of the machines have been sized to allow for adequate ventilation and at the same time reduce the propagation of noise towards the receivers.