At Kinetics Group, we believe that effective noise control is not about blocking sound indiscriminately, but about managing it intelligently without compromising operational performance. This balance is particularly critical in industrial and building services environments, where equipment must continuously ventilate, cool, and operate while coexisting with people and sensitive urban surroundings.
Industrial equipment such as dry coolers, chillers, generators, and large ventilation units remains among the most dominant sources of environmental noise in cities. As Kanev and Dolger observe, industrial equipment is often a noise source in urban spaces and disturbs people’s everyday activities, reinforcing the idea that noise mitigation is not merely an engineering preference, but a social, environmental, and regulatory responsibility (Kanev and Dolger, 2025).
Among the available mitigation strategies, louvered noise barriers represent one of the most effective yet technically demanding solutions. Designed to attenuate sound while maintaining airflow, these systems address a fundamental conflict between acoustic control and mechanical operation. Recent research presented at Forum Acusticum / Euronoise 2025 provides valuable scientific insight into how the acoustic impedance of louver blades fundamentally governs barrier performance. These findings strongly align with Kinetics Group’s decades-long experience in acoustic louvers, attenuators, and ventilation noise control systems across industrial, healthcare, and infrastructure projects.
Noise Control Without Blocking Ventilation
Traditional solid noise barriers can achieve significant sound reduction, but they often introduce serious operational limitations. As highlighted in the study, it is impossible to cover the equipment with a solid roof, as this would prevent ventilation, particularly for rooftop dry coolers and mechanical plant rooms that rely on unrestricted airflow for thermal performance and equipment reliability (Kanev and Dolger, 2025).
The real-world scenario analysed in the paper illustrates this challenge clearly. Rooftop dry coolers surrounded by rigid brick barriers successfully reduce noise levels at lower floors and ground level. However, on the upper floors the noise acts directly on the windows and terraces and its level is still too high, exposing the limitations of conventional barriers where vertical diffraction becomes dominant (Kanev and Dolger, 2025). This condition is frequently encountered in dense urban developments, hotels, hospitals, and mixed-use buildings.
It is precisely under these constraints that louvered noise barriers emerge as a superior and more adaptable solution.
How Louvered Noise Barriers Work
The research separates sound transmission through louvered barriers into two fundamental components: sound diffracting over the top edge of the barrier, and sound penetrating through the louver openings themselves. Kanev and Dolger explain that the sound transmitted through the louvered barrier can be divided into diffraction around the upper edge and penetration through the barrier itself, allowing designers to focus optimisation efforts on the second component, which is directly influenced by louver geometry and surface properties (Kanev and Dolger, 2025).
At Kinetics Group, this principle underpins our approach to acoustic louvers and ventilated noise screens. The most effective performance gains are achieved not by increasing mass alone, but by controlling wave behaviour within the airflow path, using acoustics as a design variable rather than an afterthought.
Why Rigid Louvers Are Not Enough
One of the most important findings of the study is that rigid louver blades provide limited acoustic benefit. Simulation results demonstrate that rigid blades are not so effective because sound energy penetrates through the barrier, with measurable attenuation occurring only in narrow frequency bands and strongly dependent on blade inclination (Kanev and Dolger, 2025).
Even when rigid louvers are inclined, their performance remains narrowband and inconsistent. This reinforces a fundamental acoustic principle: reflection alone does not equal noise control. Without absorption or impedance tuning, sound energy inevitably finds transmission paths through the structure.
This conclusion closely mirrors Kinetics’ field experience, where visually enclosed equipment using architectural or purely aesthetic louvers frequently fails to meet environmental noise criteria once measured on site.
Absorptive Louvers and Broadband Noise Reduction
When louver surfaces incorporate acoustic absorption, performance improves significantly. The study shows that dissipative louvre blades reduce sound more effectively, providing consistent attenuation across a wide frequency range (Kanev and Dolger, 2025).
Even non-inclined absorptive louvers achieved 10 to 20 dB of attenuation between 100 and 1000 Hz, with peak effectiveness between 200 and 500 Hz, a frequency range highly relevant to mechanical equipment noise. The authors note that this behaviour resembles the performance of a plate muffler used for ducts, confirming the shared physical mechanisms between duct acoustics and louvered barriers (Kanev and Dolger, 2025).
This finding directly validates Kinetics Group’s use of acoustically lined louvers and hybrid louver–attenuator systems, particularly in hospitals, data centres, district cooling plants, and infrastructure projects where broadband noise control is essential.
Reactive Impedance and Low-Frequency Noise Control
One of the most technically significant aspects of the research relates to reactive (non-dissipative) acoustic impedance. The study demonstrates that at low frequencies, under certain conditions, all eigenmodes in the gap between the louvers are non-uniform, effectively preventing sound propagation through the barrier (Kanev and Dolger, 2025).
As a result, louvers with reactive impedance achieved exceptionally high attenuation at low frequencies, particularly below 500 Hz, which is precisely where industrial equipment noise is most problematic. Kanev and Dolger conclude that industrial equipment typically emits low-frequency noise, so in this case, louvers with reactive impedance may be more suitable (Kanev and Dolger, 2025).
At Kinetics Group, this insight supports advanced solutions such as tuned acoustic louvers, reactive silencer–louver hybrids, and low-frequency-optimised ventilation noise barriers. These systems go beyond conventional absorption, using wave physics and modal control to deliver performance where traditional materials struggle.
The Importance of Geometry: Angle, Spacing, and Depth
The research also confirms that geometry plays a decisive role in louver performance. Increased louver inclination improves attenuation not only due to redirection, but because the distance between the louvers decreases with increasing angle, intensifying acoustic interaction within the airflow path (Kanev and Dolger, 2025).
This reinforces a core engineering principle embraced by Kinetics Group: design always outperforms catalogue selection. Louver depth, spacing, blade thickness, inclination, and surface impedance must be optimised together as a system, rather than treated as independent variables.
Implications for Kinetics Group Projects
This research provides scientific validation for practices Kinetics Group has implemented across hundreds of projects worldwide:
- Ventilation and noise control must be designed together
- Absorption alone is not always sufficient
- Low-frequency noise requires impedance-based solutions
- Simulation-driven design is essential for predictable performance
Whether addressing rooftop plant noise, generator enclosures, hospital ventilation systems, or data centre cooling infrastructure, louvered noise barriers must be engineered, not improvised.
From Research to Real-World Excellence
Kanev and Dolger conclude that selecting the acoustic properties of the louvers is crucial for designing effective ventilated barriers, and that further optimisation of louver dimensions and spacing is essential for maximising performance (Kanev and Dolger, 2025).
At Kinetics Group, we transform research-backed acoustic science into real-world, buildable, and testable solutions. Our expertise bridges simulation, manufacturing, and site implementation, ensuring that ventilated noise barriers and acoustic louvers perform as intended — without compromise.
For acoustic design support and engineered noise control solutions, contact:
Email: info@kineticsgroup.ae | sales@kineticsgroup.ae
Telephone: +971 4 885 7361
Website: www.kineticsgroup.ae
Because true acoustic excellence is not about stopping air — it is about stopping noise.
Reference
Kanev, N. and Dolger, A. (2025) Sound attenuation of louvered noise barriers for industrial equipment. Proceedings of Forum Acusticum / Euronoise 2025, 11th Convention of the European Acoustics Association, Málaga, Spain. Available at: https://www.researchgate.net/publication/396181690_Sound_attenuation_of_louvered_noise_barriers_for_industrial_equipment (Accessed: June 2025).
