Acoustic Enclosures: a transformative solution to noise control

Acoustic enclosures are largely implemented in the industry to limit excessive noisiness of machines and installations that are situated outside of production settings and technological equipment. The latter are usually responsible for the acoustic degradation of the environment and personnel’s health.

In this article, we briefly introduce their function for noise control. In particular, we try to determine the influence of materials and constructional solutions on the acoustic effectiveness of enclosures

Introduction

An enclosure serves as a passive device designed to impose limitations on noise. It often represents the sole viable method for curtailing sound radiation generated by acoustically active machinery or their components within an industrial facility.

Its significance lies in its ability to reduce noise levels in the immediate vicinity of the noise source. This is crucial for safeguarding workplaces situated in proximity of inhabited centers, especially when dealing with noise emanating from within production halls.

Practical experience indicates that enclosures play a pivotal role among the array of anti-noise protection measures employed to mitigate excessive industrial noise impacting acoustically shielded areas. Scientific research into the application of sound-absorbing and insulating enclosures has been ongoing for many years within various highly industrialized ecosystems.

Types of enclosures

In practical implementation, four types of enclosures are commonly utilized: partial, partially closed, fully closed, and integrated enclosures. On the other hand, the constructional solution of the enclosure is influenced by various factors, including the type and operational principle of the noisy machine, its production or technological process, and the specific requirements for a given acoustic insulation standard.

Fig. 1, Source: Enclosure solution studies of acoustic effectiveness under real conditions (J. Sikora)

In addition to the classification outlined earlier, further categorizations can be established by considering more detailed criteria, including:

• Thermal requirements related to the enclosed machine;
• Accessibility to the machine for repairs and during the course of production or technological processes;
• The nature of the technological or production process undertaken by the enclosed machine;
• The necessary acoustic effectiveness of the enclosure;
• The incorporation of automation elements in the constructional design of the enclosure;
• The shape of the enclosure.

Factors influencing the acoustic effectiveness of Enclosures

A measure of the enclosure effectiveness is represented by its acoustic insulation D_obud, which indicated to what extent the enclosure protects against the penetration of the air vibration as well as the material vibration within the outside.

The acoustic insulation of an enclosure primarily relies on the specific acoustic properties of its walls. The effectiveness of the enclosure’s acoustic insulation is determined by the physical characteristics of the construction materials and the overall design. Moreover, the acoustic insulation of the enclosure walls is influenced by material factors such as the volume density of the wall material, the longitudinal modulus of elasticity, the internal loss coefficient within the wall thickness, the frequency of the incident sound wave, and the void ratio of the wall material.

Additionally, various constructional factors impact the acoustic insulation characteristics of the enclosure wall, including:

• The acoustic homogeneity or heterogeneity of the wall surface;
• The types of joints and the method of fastening the wall to the structure;
• The overall tightness of the wall across its entire surface, and so on.

Application of Acoustic Enclosures by Stopson Italiana: a few case studies

Stopson Italiana has been a player in the global soundproofing market for decades, serving as a leading manufacturer of soundproofing enclosures and control cabins. The equipment offered by Stopson Italiana is designed to meet high-level technical specifications and cater to custom-made requirements, effectively providing solutions for acoustically isolating noisy machinery or establishing quiet rooms.

Key offerings include:

• Machinery Soundproofing: This involves enclosing machinery within specialized enclosures, ensuring comprehensive protection against noise by effectively isolating the noise source.
• Soundproofed Control Cabins: Stopson Italiana provides soundproof control cabins to shield operators from external noise. These cabins are applicable in various settings such as in-plant offices, control booths, test cabins, control rooms, and electro-acoustic laboratories.

This range of solutions reflects Stopson Italiana’s commitment to addressing diverse soundproofing needs across different industries and environments. Stopson Italiana has successfully implemented its Acoustic Enclosures through successful projects around Italy and not only, helping different types of industrial setting overcome their noise-insulation challenges.

Some of our success cases:

• 4 Acoustic Enclosures had been installed and allocated to the gas turbines, generators and auxiliaries within the 800 MW gas-fired power plant, located in the municipality of Turbigo, Italy. Read in detail HERE.
• The supply of 3 Acoustic Enclosures had been brough to completion in the Trigeneration Power Plant – a combined electricity and thermal power plant – of Rovera, Italy. Read in detail HERE.
• Acoustic Enclosures have been chosen as the most effective soundproofing intervention for the Enel Green Power plant (hydroelectric power plant) in Bordogna, Italy. Read in detail HERE.