Outdoor Ventilation Noise Control for Impress with Custom PZP Enclosure

Project Overview

When noise from four outdoor ventilators began disrupting the peace in a local community in Austria, authorities intervened. Impress, the company responsible for the units, was required to reduce the sound pressure level (SPL) to below 67 dB.

DECIBEL was brought in to engineer and implement a comprehensive soundproofing solution that would reduce outdoor noise to acceptable levels while ensuring the ventilation system remained fully operational.

Challenge

The ventilators were positioned in an open courtyard, creating a direct path for noise transmission to the surrounding environment. The size of the installation and the lack of pre-existing acoustic barriers made the challenge more complex.

The solution had to:

• Achieve measurable SPL reduction
• Maintain ventilation efficiency
• Withstand outdoor conditions
• Integrate floor-level insulation without interrupting access

Scope of Work

• Design and installation of a custom-built soundproof enclosure made of PZP Panels 100mm (with waterproofing on the roof and non-standard dimensions to fit the space)
• Installation of a soundproof maintenance door (2000x1000x100mm)
• Application of PZP Panels 100mm without back sides behind the ventilators and structural tower
• Construction of a rear-facing soundproof barrier (50m long x 2m high)
• Installation of galvanised steel Solid Panels 50mm beneath the floor for sub-surface noise insulation (200m² treated area)

Solution

A fully enclosed soundproof cabin was constructed around the ventilation units using DECIBEL’s high-performance PZP acoustic panels. The roof was built with waterproof acoustic panels to withstand weather exposure, and access was ensured with a custom soundproof door.

To address low-frequency noise leaking from the floor, a separate treatment was applied below the surface using custom-made solid panels 50mm, mounted under the existing structure.

The entire solution was tailored through simulation modelling to ensure the design met the SPL target of 67 dB at receiver locations in the courtyard.

Result

The implementation successfully reduced SPL to meet regulatory requirements. The final measurements confirmed that the enclosure performed as predicted by the acoustic simulation model.

This project showcases DECIBEL’s expertise in outdoor industrial noise control, particularly in high-stakes environments where compliance, design constraints, and technical performance must work in tandem.

Looking for a tailored outdoor soundproofing solution? Get in touch with DECIBEL!