noise barriers for mp impianti

Innovative acoustic solutions: Stopson Italiana’s noise barriers for an heating plant in Milan

Stopson Italiana has successfully completed the design and installation of two noise barriers for a district heating plant in Milan. This project aimed to minimize the acoustic impact of the plant on its urban surroundings, setting a benchmark in noise mitigation for industrial environments.

The project: enhancing acoustic comfort

The plant, characterized by sections for cogenerationboiler heatingthermal exchange, and summer cooling energy production, required targeted acoustic solutions to address the noise generated by ventilation and air-conditioning units.

Stopson Italiana installed two distinct types of noise barriers:

Open acoustic barrier

Positioned at a height of 6 meters and secured to the building’s exterior wall with brackets and uprights, this 3.5-meter-tall barrier is designed to absorb and isolate sound from ventilation groups. Its structure combines acoustic steel panels, offering high performance in noise reduction.

Closed acoustic barrier

Installed on the building’s roof, this 2.5-meter-tall barrier is complemented by acoustic louvers to ensure airflow while reducing noise from air-conditioning units. This enclosed design effectively prevents noise propagation in open environments.

The barriers achieved noise reductions exceeding the client’s expectations, with performance metrics including:

  • 7 dB attenuation for the open barrier.
  • 5 dB attenuation for the closed barrier.

noise barriers for mp impianti

Stopson Italiana’s expertise in acoustic barriers

Stopson Italiana specializes in designing customized acoustic barriers, using materials such as painted steelaluminumcorten steel, and even wood or glass. These solutions cater to diverse industries and applications, including traffic noise control, industrial plants, and energy production facilities.

Each solution is tailored to meet the most stringent technical specifications, ensuring a reduction of noise pollution while preserving operational efficiency.

Conclusion: commitment to a quieter future

This intervention not only underscores Stopson Italiana’s expertise in noise pollution control but also reinforces their commitment to sustainable and innovative acoustic solutions. With this project, the company has once again demonstrated its ability to exceed client expectations, achieving effective noise reduction and improving environmental quality in urban areas.

steam vent silencer for vaultec umisa

Installation of Stopson Italiana Silencers for RDM Cartonboard in Barcelona

Stopson Italiana recently completed a crucial intervention at the RDM Cartonboard paper mill in Barcelona. In collaboration with Valtec-Umisa, the company supplied and installed two silencers: an SPM multi-inlet model and an SVC model with core. These devices ensured maximum noise reduction for the plant, significantly improving its acoustic efficiency.

RDM Cartonboard Project: Technical Details

The RDM Cartonboard plant includes a CPR-50 steam generator capable of producing up to 50,700 kg/h of steam at 12 bar. Stopson Italiana contributed with the installation of two custom silencers to optimize acoustic performance and ensure compliance with noise regulations.

SPM Multi-Inlet Silencer

Functioning Principle and Advantages

The steam vent silencer model SPM was designed to combine all steam lines into a single body. This system allows for the simultaneous operation of two lines, each equipped with a specific diffuser that directs the flow toward the upper absorbing section.

Thanks to this configuration, Stopson Italiana achieved two key objectives:

  • High acoustic performance: noise reduction to 85 dB(A) at one meter.
  • Space optimization: the compact design of the silencer minimizes footprint while maintaining high noise absorption efficiency.

SVC Silencer with Core

Silencers SVC installed for Valtec-Umisa

Customized Design

The SVC model, designed with a three-concentric-ring structure and flanged casing, was specifically developed for bypass lines. This device uses sound-absorbing materials protected by perforated sheets, ensuring optimal performance with minimal pressure loss.

Applications and Performance

The SVC silencer ensures high operational efficiency even at operating temperatures up to 100°C, making it an ideal solution for soundproofing ventilation ducts and bypass systems.

Client’s Feedback: Valtec-Umisa’s Opinion

Miguel Medina, SalesDirector at Valtec-Umisa, stated:

“This is not the first time we’ve relied on Stopson Italiana’s support. Even for this complex project, we were highly satisfied with the quality and performance of the silencers provided.”

Conclusion

The project at the RDM Cartonboard paper mill is another success story for Stopson Italiana. Thanks to customized and innovative solutions, the company once again demonstrated its leadership in the industrial noise control sector.

foto dello stand di stopson ala fiera enlit di milano

Stopson at Enlit Milano 2024: innovation and collaboration for a quieter future

We are pleased to share our experience at Enlit Milano 2024, held from October 22nd to 24th. It was a valuable event, enriched by the collaboration with Stopson Turkiye, MODCON, and PRODINOX, and filled with meetings and discussions with companies and professionals interested in our innovative approach to industrial soundproofing.

During the exhibition, the Stopson team presented our noise control solutions, designed to tackle the most complex acoustic challenges and improve efficiency in work environments. In particular, we highlighted our technologies that promote health and productivity in the workplace, helping to create quieter and more efficient spaces.

Our participation at Enlit was a significant opportunity to strengthen existing relationships and initiate new partnerships with those who, like us, are committed to building a more sustainable and quieter industrial future.

special thank you goes to everyone who visited our booth. We look forward to continuing to work together to design industrial environments that are increasingly efficient, safe, and environmentally friendly.

sincere thank you also to Alice Magno and VMEM for the flawless organization of the event.

CCGT power plant - Agios Nikolaos - Greece - 2021

Stopson Italiana’s services for industrial soundproofing

Stopson Italiana is a leading company in the field of noise control solutions. With decades of experience, we offer a wide range of products and services tailored to various industries. This article explores the key project areas where Stopson Italiana excels, highlighting our specialized offerings and expertise.

Industrial Noise Control

Stopson Italiana provides silencers designed for industrial applications. These devices are essential for reducing noise pollution in various environments. Our products are customized to meet specific client needs, ensuring optimal performance and compliance with industry standards.

Marine Sector Solutions

In the marine sector, noise control is crucial for maintaining a comfortable environment on board. Our marine silencers are designed to reduce noise from engines and other onboard machinery, contributing to a quieter and more pleasant journey for passengers and crew.

Power Generation Projects

Noise pollution in power generation facilities can be significant. Stopson Italiana offers engine exhaust silencers that effectively minimize noise from turbines and other power generation equipment. These solutions help maintain regulatory compliance and improve the working environment for personnel.

Oil & Gas Industry Applications

The oil and gas industry demands robust noise control solutions due to the high levels of noise generated during extraction and processing. Our vent silencers are specifically designed to handle the intense conditions of oil and gas operations, ensuring effective noise reduction and enhanced safety.

Ventilation Systems

Proper ventilation is essential for industrial safety and efficiency. Stopson Italiana’s ventilation duct silencers are engineered to reduce noise in ventilation systems, ensuring a quieter and more efficient airflow. These silencers are ideal for various industrial applications, including HVAC systems and manufacturing facilities.

Conclusion

Stopson Italiana’s comprehensive range of noise control solutions is designed to meet the diverse needs of various industries. Our expertise in designing and manufacturing customized products ensures that we can provide the most effective noise reduction solutions for any application. Explore our offerings and discover how we can help you achieve a quieter and more efficient working environment.

Stopson Turkiye acquires a new key accreditation with the ASME Certificate for U-Stamp

Stopson Turkiye makes the first step towards the highest manufacturing performance for unfired pressure vessels: ASME Certificate for U-Stamp achieved!

An introduction to U-Stamp and ASME Certificate

U-Stamp is the official acknowledgement that an unfired pressure vessel is designed, manufactured and controlled in accordance with ASME VIII Div.1 Rules.

ASME Codes are the most famous international references for manufacturing of pressure retaining equipment that allow the installation of safe equipment, available to resist for all its life cycle to any design and process condition, with safety margin avoiding undesired failures.

U-Stamp is also the fundamental requirement that any pressure retaining equipment needs to have in order to be installed in North America.

This achievement thus certifies the capability of Stopson Turkiye to deliver silencers manufactured according to the highest standard and that can be installed all over the world, in any plant and at any condition.

The process

ASME Certificate of Stopson Turkiye means that any silencer which needs a U-Stamp Robust mechanical and structural analysis from qualified Engineering Team

  • Efficient and well-oiled internal management process
  • Highest quality check on raw material
  • Detailed check on all manufacturing activity under supervision of qualified QC Department 
  • Review of engineering and manufacturing procedure by ASME qualified consultant agency

Personnel and processes involved in manufacturing of silencers according to ASME VIII Div.1 are constantly trained and informed in case of any latest release of the Codes, or of internal QC Manual.

Year after year our team and our organization will be certified, confirming top level processes and ensuring to all our customers the guarantee of top ranked products.

The team

The certification process commenced early December 2023 and, with support of ASME Authorized Inspection Agency, led to conclusion in just 3 months thanks to the close and productive cooperation of an amazing Team:
  • Technical Manager: Olgay Yıldırım
  • Design Manager: Luca Fenini
  • Quality Team Leader: Umut Güven
  • Quality Assurance Engineer: Ayşe Turgut
  • III Level Inspector: Ekim Tepe

Thanks to the amazing team for achieving this milestone!

In-Line Silencers by Stopson Italiana

In-Line Silencers are a type of Silencers designed to mitigate the noise produced by valves or compressors

These silencers, characterized by their exclusive design and manufacturing, require in-depth engineering expertise, field experience, and meticulous quality processes to ensure the delivery of high-performing and safe products.

In-Line silencers are adept at reducing the noise emitted by control valves or compressors within pipelines

By strategically integrating In-Line Silencers into the piping system, noise levels can be effectively diminished. 

If interested in learning more about Stopson Italiana’s In-Line Silencers, including details about specialized materials, testing procedures, and the engineering process, click HERE.

Insights into Noise Pollution

Excessive noise, commonly referred to as noise pollution, poses a significant threat to human well-being globally. It primarily stems from atmospheric, environmental, and occupational sources, including industrial machinery and indoor equipment.

Industrial workers often face hazardous noise levels, endangering their health. Despite regulations in many countries aimed at reducing noise hazards, enforcement remains inconsistent, resulting in variations in noise laws and ordinances worldwide.

In order to comprehend the intricacies of industrial noise, and consequently, the techniques employed for soundproofing, it is imperative to embark on an exploration of sound and noise pollution.

 

Introduction: Classes of noise and noise pollution 

As already discussed in previous publications, noise pollution is the disturbing noise that can harm human well-being, and it has become a significant concern in today’s industrial environments.

Noise is pervasive, with some industrial areas experiencing particularly loud continuous noise. Physically, there’s no difference between sound and noise; noise refers to undesired sound and any unnecessary disturbance within a useful frequency band.

Generally speaking, most outdoor and environmental noise is caused by industrial machines, transportation systems, and indoor activities such as machinery in workplaces, building activities, household appliances, and music performances.

Noise is also defined as unwanted sound and a form of energy emitted by a vibrating body, which, upon reaching the human ear, creates the sensation of hearing through nerves. Not all sounds produced by vibrating bodies are audible; the audible range is typically between 20 Hz to 20 kHz. Frequencies below 20 Hz are called infrasonics, and those above 20 kHz are termed ultrasonics.

Noise can be continuous or intermittent, and it may be of high or low frequency, both of which are undesirable for normal human hearing.

The distinction between sound and noise can also depend on the recipient’s inclination and interest, ambient conditions, and the impact of the sound at that moment. Noise intensity is typically measured in logarithmic units (dB) because this scale allows a wide range of pressures to be described without using large numbers and represents the nonlinear behavior of the ear more accurately.

Let’s examine three distinct classes of noise:

  • Atmospheric noise: This type of radio noise arises from natural atmospheric phenomena, primarily lightning discharges during thunderstorms. Worldwide, approximately 3.5 million lightning flashes occur daily, constituting atmospheric noise, with cloud-to-ground flashes being more prevalent. At very low frequencies (VLF) and low frequencies (LF), atmospheric noise tends to dominate, while at high frequencies (HF), man-made noise, especially in urban areas, is more prominent.
  • Environmental noise: Environmental noise encompasses noise pollution from external sources, primarily caused by transportation systems such as buses, trains, cars, aircraft, and recreational activities like sports and music performances. This type of noise is present in various human activities and can have diverse effects on individuals, ranging from emotional to physiological and psychological. While low-level noise may not be harmful, prolonged exposure to environmental noise can lead to annoyance, sleep disturbances, hearing loss, and stress-related problems. Transportation noise originates from engine/exhaust and aerodynamic sources, while recreational noise can come from various activities and processes. Additionally, background noise from alarms, conversations, and bioacoustic sources like animals or birds contributes to environmental noise.
  • Occupational noise: This refers to noise that affects workers during their job duties, either from the work environment or the machinery they operate. Industrial noise varies in intensity, frequency components, and consistency. Some machinery produces continuous noise with a relatively uniform frequency response and consistent level, while others exhibit intermittent periods of higher noise levels amidst lower background noise.

Technical terms and detailed related to noise pollution

The definitions of key technical terms concerning noise pollution measurement parameters and indicators are sourced from the American National Standards Institute (ANSI) standards, ANSI S1.1-1994 or ANSI S3.20-1995, as per the terminology employed in those standards:

  • Audiogram: A graphical representation of hearing threshold levels plotted against frequency. Frequencies below 20 Hz are termed infrasonics, while those above 20,000 Hz are referred to as ultrasonics.
  • Baseline Audiogram: The initial audiogram against which subsequent ones are compared to assess significant threshold shifts. It is obtained from an audiometric examination conducted before or within the first 30 days of employment following at least 12 hours of silence.
  • Continuous Noise: Noise characterized by negligible fluctuations in level during the observation period.
  • Crest Factor: Ten times the base-10 logarithm of the square of the wideband peak amplitude of a signal to the time-mean-square amplitude over a specified time period.
  • Decibel, A-weighted (dBA): The sound level measured using the A-weighting network on a sound level meter.
  • Decibel, C-weighted (dBC): The sound level measured using the C-weighting network on a sound level meter.
  • Noise Reduction Rating (NRR): An indicator of a hearing protector’s noise reduction capabilities, expressed in decibels (dB). It is a single-number rating required by law to be displayed on the label of each hearing protector sold in the USA.
  • Derate: The process of using a fraction of a hearing protector’s NRR to calculate the noise exposure of a worker wearing that protector.

The Effects of noise pollution on human health

Noise pollution has significant societal costs, prompting commitments from organizations like the European Commission (EC) and the World Health Organization (WHO) to stringent noise reduction targets.

Acute noise exposure triggers the release of stress hormones, such as adrenaline, leading to changes in normal bodily functions. Severe effects can occur even at relatively low environmental noise levels, disrupting concentration, relaxation, or sleep. Night-time noise, in particular, may impact cardiovascular health due to sleep disturbances.

WHO recommends night-time noise levels below 55 dB(A) to prevent adverse health effects in the short term, with a long-term goal of 40 dB(A). Common effects of noise pollution on vulnerable populations include annoyance, sleep disturbance, heart and circulation problems, diminished quality of life, cognitive impairment, and hearing loss. Prolonged exposure to continuous noise levels of 85–90 dB(A) in industrial settings can result in progressive hearing loss, particularly in the frequency range of 3 kHz to 6 kHz. Speech intelligibility can be reduced even at 10 dB, with noticeable social hearing handicaps above 30 dB. The impact of noise on health can vary based on sound characteristics such as intensity, frequency, complexity, and duration.

 

Industrial soundproofing systems, like those offered by STOPSON ITALIANA, are specifically designed to mitigate the effects of noise pollution in industrial settings. These systems target the type of noise described previously, focusing on reducing noise levels generated by industrial processes and machinery.

By implementing soundproofing solutions from Stopson Italiana, industrial facilities can effectively combat this type of noise, creating a quieter and safer working environment for employees and surrounding communities.

Stopson Italiana extends warm wishes to you and your team for a joyful Christmas and a festive holiday season!

Season’s Greetings from Stopson Italiana!

Reflecting on the concluding year, 2023 has seen us proudly solidify again our position as a distinguished global industry leader. Our comprehensive understanding of soundproofing patterns and engineering practices has been pivotal in our continuous efforts to elevate product performance.

This year marked a significant milestone with the establishment of Stopson Türkiye, born from the merger of Turkish leaders Modcon Makina and Prodinox Metal. Building on a robust relationship since 2016, this strategic partnership unites three companies with complementary expertise, creating a unified entity dedicated to delivering high-quality, reliable products and services globally.

The establishment of Stopson Türkiye represented a significant step forward, combining diverse strengths into a unified entity dedicated to delivering high-quality, reliable products and services to meet the evolving needs of customers worldwide.

At the same time, we expanded our portfolio with numerous successful projects, reinforcing our unwavering international commitment. As in previous years, plants and industrial complexes entrusted us to effectively address and eliminate noise pollution in their production environments.

Looking ahead to 2024, our commitment to innovation remains steadfast as we strive to enhance our offerings and provide customers with the utmost reliability in soundproofing products and services.

We express sincere gratitude to our valued customers, communities, partners, and stakeholders for their unwavering support throughout the year.

Wishing you and your team a Merry Christmas and a Happy New Year!

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 Dobud, 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.

Noise control. An historical excursus

Exposure to high noise levels poses significant risks of permanent hearing loss. Many industries are thus highly motivated to discover cost-effective solutions to address this issue.

The absence of suitable acoustic treatment in industrial setting can, in the best-case scenarios, disrupt the productivity of individuals within these spaces. Even if the noise is not harmful or particularly bothersome, it becomes undesirable when it hinders effective communication among coworkers.

As we have already discussed, much can be done to reduce the seriousness of noise problems. Effective equipment and methods are available for eradicating the noise generated by several engineering systems.

Have you ever considered the origins of these developments? This article offers a comprehensive examination of the historical evolution of industrial soundproofing.

 

Industrial noise control: historical background

Acoustics, owing to its connection with music, has been a subject of interest for many centuries.

It can be traced back to the Greek philosopher Pythagoras, who conducted early investigations into the physical origins of musical sounds around 550 BC. He observed that when two strings on a musical instrument are plucked, the shorter string produces a higher-pitched sound than the longer one. Notably, if the shorter string’s length is halved compared to the longer one, it emits a note that is one octave higher, signifying a twofold difference in frequency or pitch.

This foundational understanding led to the practice of measuring sound across standard octave bands or frequency ranges encompassing one octave. As a matter of fact, determining the frequency distribution of machinery-generated noise is critical for choosing effective noise control methods.

Credit is generally attributed to the Franciscan friar Marin Mersenne (1588–1648) for the earliest published analysis of string vibration, which he presented in 1636. Mersenne measured the vibrational frequency of an audible tone (84 Hz) produced by a long string. He also noted that the frequency ratio for two musical notes separated by an octave was 2:1.

A well-known scientist has made significant contributions to the field of sound control: in 1638, Galileo Galilei published a treatise on the vibration of strings, in which he established quantitative relationships between the frequency of string vibration, its length, tension, and density. Galileo observed that when different pendulums with varying lengths were set in motion, the resulting oscillations created pleasing patterns if the frequencies of these pendulums had specific ratios, such as 2:1, 3:2, and 5:4, corresponding to the octave, perfect fifth, and major third intervals in music.

In 1713, the English mathematician Brook Taylor, who is also known for developing the Taylor series, mathematically solved the shape of a vibrating string. His equation allowed for the derivation of a formula for the string’s vibration frequency that perfectly matched the experimental findings of Galileo and Mersenne.

In the early stages of acoustics, a precursor to the stethoscope was developed by French physician Rene Laennec in 1819. This device was employed for clinical purposes. In 1827, Sir Charles Wheatstone, a British physicist known for inventing the Wheatstone bridge, created an instrument similar to the stethoscope, which he named a “microphone.”

Following the invention of the triode vacuum tube in 1907 and the initial development of radio broadcasting in the 1920s, electric microphones and loudspeakers became available. These innovations paved the way to produce precise instruments designed to measure sound pressure levels and other acoustic parameters with greater accuracy than the human ear could provide.

Between the 1930s and 1940s, noise control principles started being applied to various areas, including buildings, automobiles, aircraft, and ships. During this time, researchers also began exploring the physical processes involved in sound absorption by porous acoustic materials.

With the outbreak of World War II, there was a renewed focus on addressing speech communication issues in noisy environments, such as tanks and aircraft. In the US, the National Defense Research Committee established two laboratories at Harvard University to tackle these concerns: the Psycho-Acoustic Laboratory studied sound control techniques in combat vehicles, while the Electro-Acoustic Laboratory researched communication equipment for noisy environments and acoustic materials for noise control. After the war, noise control research continued at various universities.

Post-war, noise problems in architecture and industry were finally addressed. Research was directed at solving residential, workplace, and transportation noise issues predominantly. An important development for industrial soundproofing was the 1969 US amendment to the Walsh–Healy Act, which imposed strict limits (e.g., 90 dBA for an 8-hour period) on noise exposure for industrial workers. This law also mandated the provision and training in the use of personal hearing protection devices if the noise exposure couldn’t be prevented.

 

Contemporary industrial noise control

The 1969 US amendment escalated a series of environmental regulations that were aimed at tackling noise pollution at a global level. Starting from 1970s, industrial facilities around the world were finally required to meet specific noise level standards, driving the need for effective soundproofing solutions.

During this period, industrial soundproofing primarily relied on traditional methods like installing acoustic panels, enclosures, and barriers. These methods were effective but often bulky and expensive. Nevertheless, these are still largely employed nowadays.

The 1980s and 1990s brought advancements in acoustic materials. On the one hand, these decades saw the development of innovative materials that offered better sound absorption and noise isolation properties. Fiberglass, mineral wool, and other materials became popular choices. On the other hand, advancements in manufacturing and construction technologies allowed for more efficient installation of soundproofing solutions. This period also witnessed the introduction of computer simulations for noise control design.

During the 2000s, the focus had been shifted on growing environmental awareness to make soundproofing measures more eco-friendly. Recycled and sustainable materials at this point gained more and more popularity. At the same time, manufactures began offering customized designs to address specific industrial noise challenges effectively.

Stopson Italiana has been an integral part of the industry’s evolutionary journey. With over 56 years of operational history, Stopson Italiana asserts its position as a leading company in the global noise control sector.

Our distinguishing factors include:

  1. Decades of experience, driving ongoing product enhancement;
  2. Tireless dedication to advancing technology and competitiveness;
  3. Profound expertise in soundproofing techniques;
  4. A track record of overseeing thousands of successful installations in various case studies.

Particularly, Stopson Italiana have become a company of choice when it comes to customizing service and product according to specific customer needs.

Learn more in detail about our soundproofing solutions HERE.

Different types of noise sources in industrial plants

Within industrial plants, while designing solutions for noise control, it is crucial to estimate how loud a specific noise source might be, especially in absence of actual measurements for any specific source.

But first, it is imperative to identify which are main noise sources and their characteristics. The goal of this article is to examine the main noise sources from several mechanical systems in industrial plants.

 

Main noise sources

 

1. Fan noise

Industrial fans come in different types with distinct noise features:

  1. Centrifugal fan with airfoil blades: used in large heating, ventilation, and air conditioning systems for clean air.
  2. Centrifugal fan with backward curved blades: used for general ventilation and air conditioning, with higher efficiency.
  3. Centrifugal fan with radial blades: commonly used in material handling systems.
  4. Centrifugal fan with forward curved blades: used for low-pressure and low-speed applications like home air conditioning.
  5. Tubular centrifugal fan: used in heating and ventilation for low-pressure return-air systems.
  6. Vaneaxial fan: suitable for medium to high-pressure applications but tends to be noisier.
  7. Tubeaxial fan: used in low to medium-pressure applications.
  8. Propeller fan: suitable for handling large volumes of air, used in roof exhaust systems and cooling towers.

 

2. Electric motor noise

While individual electric motors are not usually very excessive, the noise can add up when managing different machines together. Various factors contribute to motor noise, including windage noise from cooling fans, rotor-slot noise, rotor-stator noise, magnetic flux changes, dynamic unbalance, and bearing noise.

 

3. Pump noise

Pump noise comes from hydraulic and mechanical sources. Key noise sources include cavitation, fluid pressure fluctuations, impact on solid surfaces, and rotor imbalance. Proper vibration isolation can reduce structure-borne noise from pumps.

 

4. Gas compressor noise

Gas compressors belong to the category of machinery where it is crucial to prioritize efficiency and durability over noise reduction. Many gas compressors are not designed with low noise emission as the primary design criterion. Therefore, typically, noise control measures are implemented post-construction. The variables influencing noise levels encompass the compressor’s power input, the turbulence of the fluid, and the nature of the gas being compressed.

 

5. Noise from gas vents

One of the more serious noise problems in industrial plants is the noise produced by the discharge of air, steam, or process gas into the atmosphere. Blow-off nozzles, steam vents, and pneumatic control discharge vents are some examples of noisy venting situations. Noise from these vents results from turbulent mixing, and the frequency of the noise depends on the size of the turbulent eddies.

 

6. Valve noise

Valves and regulators used with steam and gas lines can be a significant source of noise. There are two primary sources of noise generated by valves: (a) mechanical noise generation and (b) fluid noise generation, either hydraulic for liquids or aerodynamic for gases.

Mechanical noise comes from pressure fluctuations and fluid impingement, while fluid noise is either hydraulic or aerodynamic. Valve vibration noise can indicate potential issues with the valve.

 

7. Air distribution system noise

In heating, ventilation, and air conditioning (HVAC) systems, noise can be transmitted from the air-handling unit into the duct system. Additional noise may be generated as air flows through various components like elbows, fittings, grills, and diffusers.

 

Measures for noise control

Understanding and managing these different noise sources is crucial for maintaining a comfortable and safe working environment in industrial plants.

To effectively manage noise as it travels from its source to the receiver, typically a worker, a careful consideration of certain procedures is imperative in order to select the most suitable infrastructure within the industrial plant. Among the most proficient soundproofing procedures are:

  • Employing Vent Silencers (for valves and tanks) designed to lower the noise levels produced by exhaust piping for pressurized gaseous fluids when vented to the atmosphere.
  • Utilizing Acoustic Barriers, whether in the form of single walls, partial enclosures, or full enclosures for entire pieces of equipment.
  • Installing Enclosures around noisy components within machinery.
  • Implementing either Reactive or Dissipative Mufflers: the former for addressing low-frequency noise or smaller exhausts, and the latter for dealing with high-frequency noise or larger diameter exhaust outlets.
  • Incorporating In-line Plenum Chambers or lined ducts into air handling systems.
  • Managing reverberation by adding sound-absorbing materials to spaces with excessive reflected noise. It is important to note that this approach may not significantly affect the direct sound reaching the receiver.
  • Exploring active noise control techniques, which involve manipulating the reflection, suppression, or absorption of noise emitted by an existing sound source through the use of one or more secondary or control sources.

Discover Stopson Italiana’s offering and find the solution that best fit your requirements HERE.