A Discharge Plenum Silencer Case Study

45 Lisgar

Silencer and acoustic barrier solution caps noise for a
condominium air cooled chiller


A condominium in a dense part of downtown Toronto was struggling with major noise emissions from a new, air-cooled chiller. Its constant rattle and tonal hum were causing problems for locals and residents who could hear the chiller even with their windows shut. The property manager faced a raft of complaints from abutting neighbors, resulting in forced action imposed by the city’s by-law department.

The Project Facility
High Rise Condominium

The Noise Source
Air Cooled Chiller

The Solution
Discharge plenum silencer and a
perimeter acoustic barrier

The Project Team
Property Management Company
Acoustic Consultant HGC

Reason for Mitigation:
Municipal Noise Bylaw

Project Challenges

Stringent Parameters

Collaborating with the acoustical consultant assigned to the project, it became obvious that noise levels from the chiller were significant and well outside acceptable acoustic limits. The consultant conducted extensive testing and discovered that sound levels from the unit would need to be lowered to 53 decibels from 71 to comply with local noise ordinances. The solution design also had to take into account the tonal nature of the equipment’s operating sound levels.


The downtown location created significant logistical constraints around the site. Access was limited, and the high rise building had residents who needed 24-hour access to the complex.
Our team worked with city officials to schedule road closures, while limiting traffic and carefully managing crane time. Parklane designed the entire solution in a modular fashion to dramatically reduce the need for on-site fabrication.

Building Capacity

Because of the retrofit nature of the project, the solution design had to work within the weight capacity of the building and available space for implementation.

Given the building’s proximity to Lake Ontario, significant wind loads also needed to be accounted for. The uniquely designed operational array made effective use of the strongest parts of the building structure to avoid any intrusive enhancements or additional support requirements.

Project Solution


In order to bring the noise into line with the municipal bylaws, Parklane implemented a two-part solution. First, a plenum silencer at the top of the chiller with maintenance door access for its fan components, paired with a perimeter acoustic barrier wall to shield the lower–level compressors and intake air noise.

But our team of engineers understood that the silencer and barrier wall alone wouldn’t be enough. The noise emanating from the chiller was being absorbed on three sides by the barrier wall, allowing sound to reflect off of the fourth side. To prevent that reflection, we installed the second part of our mitigation solution: perforated, galvanized steel acoustic panels to absorb the remaining sound.


The solution needed to blend into the building façade, while ensuring that all parts could effectively integrate into the equipment and surrounding structure without impeding the function, capacity, or operation of either.
Parklane’s uniquely designed structural array made effective use of the strongest parts of the building structure to avoid any intrusive enhancements. To address architectural concerns, pre-finished materials for both the silencer and sound wall were carefully selected to blend into the structure.

The final system design was created collaboratively with the client’s acoustical consultant, creating an optimized solution that worked neatly within the site’s constraints.


The chiller installed as part of the renovation project generated excess noise that
exceeded the local municipal code. Parklane was able to design a highly effective
plenum silencer and acoustic enclosure that maintained the mechanical integrity of the
chiller and install it quickly and efficiently to avoid disrupting hotel operations or local
businesses. Post-installation field testing by the owner’s acoustic consultant confirmed
that the designed performance levels were achieved, and the equipment was
successfully brought into regulatory compliance.

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Find out how we helped this high rise condominium
silence their noise emissions. 

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