Rooftop Chiller Noise Control on Oborishte Street
Project Overview
DECIBEL was contacted by an engineer from Kalistratov, a construction company working on a new building located on the emblematic Oborishte Street in Sofia. The rooftop of the building was planned to host chillers for the HVAC system. To ensure that the noise from these machines would not disturb residents, the client requested a soundproofing and vibration isolation solution.
Reducing Noise from Rooftop HVAC Units in a Residential Area
Chillers and HVAC systems placed on rooftops can generate both airborne noise and structural vibrations. Without proper noise control, these sounds can travel through the building and disturb its occupants. For this project, our goal was to design a solution that would meet the acoustic requirements, reduce noise to within legal limits, and maintain the building’s operational efficiency.
Challenge
The challenge was to control both types of noise, airborne and structure-borne, in an open rooftop setting. The solution had to work within the existing construction plan and be compatible with the size and weight of the chillers. This required precise engineering calculations, custom design, and tailored manufacturing.
Scope of Work
- Conducted an on-site inspection by a DECIBEL engineer
- Recommended spring mounts for vibration isolation based on machine weight and dimensions
- Performed software acoustic simulations to design the most effective airborne noise control system
- Proposed a structural frame and PZP perforated soundproof panels for the enclosure
- Manufactured, delivered, and installed standard PZP panels
- Conducted a second inspection and produced additional custom-sized PZP panels for final installation
Solution
The final solution combined spring vibration isolators to prevent structure-borne noise and PZP perforated acoustic panels to block and absorb airborne noise from the chillers. The panels were installed on a custom-built frame, ensuring full coverage of the noise source while allowing proper ventilation for the HVAC equipment. The combination of standard and custom-made panels ensured a precise fit and maximum noise reduction.
Result
After installation, the chillers were fully enclosed with soundproofing panels and vibration isolation systems. The expected noise reduction was achieved, preventing disturbance to the residents and ensuring compliance with noise regulations for residential areas. The system is designed for long-term performance with minimal maintenance requirements.
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