Anechoic and Hemi-Anechoic Chambers: application context, design, and main benefits

The increasing demand for machinery and components with certified sound levels has led many companies to recognize the importance of having a controlled sound environment for conducting measurements. 

Nevertheless, traditional masonry rooms are not always cost-effective or flexible enough to meet these specific industrial requirements. 

Therefore, alternative solutions are being considered to better adapt to installation development and provide flexibility.


Typical applications of Anechoic and Hemi-anechoic Chambers

Anechoic chambers are targeted for various industries that require precise acoustic testing and analysis. Industries that commonly employ anechoic and hemi-anechoic chambers include:

  • Companies producing noise-generating devices or pieces of equipment. For instance, they are extensively used in the automotive sector for testing vehicle components, such as engines, exhaust systems, and vehicle interiors, to assess their noise levels, vibration characteristics, and acoustic performances. As a matter of fact, any vehicle manufacturer should perform a rigorous testing to ensure compliance with national planning standards before releasing a new model into a market.
  • Companies producing noise control products and testing facilities, as well as any organization responsible for ensuring that their services meet requirements, thereby establishing tightly regulated acoustic environments.

Designing Anechoic and Hemi-anechoic Chambers

Creating an insulated test environment is essential in the first place for precise noise analysis. 

Chambers can be either of an anechoic chamber or hemi-anechoic design pattern. What is the main difference?

  • Anechoic chambers are designed with sound-absorbent materials on all six sides, effectively eliminating external noise and controlling frequency cut-off. 
  • Hemi-anechoic chambers, on the other hand, have a solid floor with anechoic wedges on five sides, allowing examination of how noise interacts with real-world surfaces.

Anechoic and hemi-anechoic chambers are typically tailored to specific testing needs and frequency requirements, often aligned with ISO standards. 

The size of these chambers is primarily dictated by the equipment under test. Their sizes can range from extremely large ones used for instance in the case of automotive testing, to very small chambers, employed to test more compact devices.


Main benefits of Anechoic and Hemi-anechoic Chambers

As stated earlier, these chambers are instrumental to facilitate the development and testing of any noise-generating products

Another example of an industrial sector that has been significantly affected is the aerospace industry.  These chambers are particularly used in the fields of research and development to test aircraft engines, jet noise reduction technologies, aircraft interiors, and other aerospace components for noise emissions and acoustic characteristics.

In short, they give significant assistance in identifying unexpected noises and vibration issues that may arise during operations. For instance, many types of industrial machinery can be tested in a hemi-anechoic chamber to assess their vibration properties.

However, benefits are not just limited to sound isolation.

Anechoic and Hemi-anechoic chambers also provide total protection against electromagnetic interference, such as radio waves, which could disrupt the product or sensitive measuring instruments.

More importantly, unlike any other soundproofing chambers, which attenuate noise levels to around 10-20 dBA, Anechoic and Hemi-anechoic chambers can be designed to achieve even lower levels, reaching as little as -20 dBA if required.


Anechoic and Hemi-anechoic Chambers by Stopson Italiana

Stopson Italiana offers a range of prefabricated Anechoic or Hemi-anechoic Chambers that are internally treated with standard wedges, according to the lowest operating frequency. Our products are tailored for professional testing in various fields.

Our case history includes the implementation of a hemi-anechoic chamber for acoustic testing in a Home Appliances Plant, in Pordenone, Italy. The chamber in question was provided with a modular construction for easy dismantling and built with non-combustible sound absorbing materials.

Stopson Italiana’s anechoic chambers can also be optionally equipped with a control room. Such a setup provides working areas with sufficiently low sound pressure levels, limited reverberation, and ensures accurate acoustic performance.

Our anechoic chambers typically have a cut-off frequency of 125Hz and can be equipped with various features depending on their intended use. These features may include suitable interior lighting, exhaust gas extraction systems, independent ventilation and cooling systems, air-conditioned aspiration/exhaust, easy access to tested devices, safety glass for visual inspection during testing, and long-lasting soundproofing materials.

To Discover more Test Facilities Solutions offered by Stopson Italiana click HERE.

The science behind industrial soundproofing: main principles

Soundproofing approaches are critical measures to prevent harmful sound waves from permeating within industrial setting. However, choosing the appropriate strategies depends on different types of noise, essential factors to be considered while designing a safe and efficient industrial workspace.

In this regard, diving into the physics of sound and the relative methods to abate noise levels in industrial settings can be beneficial while selecting the most suitable solution for specific noise-related exigencies.


Types of noise and relative approaches

The noise industrial facility managers and industrial engineers should be concerned about can be divided into three main categories, depending on the means of transmittance: airborne noise, solid-born noise, and impact noise. Each of them requires a tailored approach to mitigation.

Airborne noise is primarily caused to the vibration of the air. More specifically, it refers to sound waves travelling through the air. In this case, the reduction strategy should be drawn on the application of materials that absorb the aforesaid sound waves, such as acoustic panels and soundproofing curtains. These are commonly known as “heat-insulating materials”, since they minimize the noise that is transmitted through the air by literally converting the sound energy into heat energy.

Solid-borne noise, on the other hand, is primarily due to the impact of solids or solid vibrations. The reduction strategy here must take into account the fact that the sound permeates walls, floors, and ceilings with ease. Accordingly, the application of specific vibration isolations materials, such as rubber mats or spring, will be required to absorb or isolate the vibration prior to being transmitted through the structure.

Impact noise, lastly, is produced by physical impacts, including footsteps and machinery vibrations. Similarly to what occurs in solid-borne noise circumstances, the best noise eradication execution can be achieved here by applying materials that absorb impact, such as thick carpets or rubber mats.

It should be also noted that sound permeation is strictly tied tomass law”: the effectiveness of a wall or plate’s soundproofing performance largely depends on how much mass it has in relation to its area. When it comes to selecting sound insulation materials, the higher the mass, the more difficult it is to make it vibrate. Opting for a dense and heavy material is hence, in most of the cases, the best option.

The effectiveness of soundproofing approaches can still vary depending on the frequency and intensity of the noise. Ultimately, a combination of soundproofing materials and techniques may be recommended to effectively reduce noise level and attain sound transmission loss.


The importance of partnering with a specialized soundproofing company

Relying on industrial noise control manufacturer may be game-changing to identify the best materials and techniques to soundproof your industrial setting and fulfill noise mitigation challenges.

Stopson Italiana, which counts on a proven reference list of partners from a variety of industries, certifies an extensive knowledge in providing industrial noise control solution on a global level.

Following an initial consultation path, a team of experts will provide support to identify the source of noise and its type, select the most appropriate soundproofing materials according to its properties, and eventually deliver the solutions that best fit your case. Stopson Italiana offers acoustic panels, sound barriers and vibration isolation materials among them.


We officially announce the birth of Stopson Türkiye

Stopson Italiana merge forces with two Turkish leaders of manufacturing to give birth to Stopson Türkiye, its first foreign entity.


The partnership

The project brings together three companies that were already part of a well-established partnership since 2016: Stopson Italiana, Modcon Makina, and Prodinox Metal.

Stopson Italiana has been pioneering the acoustic sector for more than 50 years designing and manufacturing Silencers and soundproofing solutions, as well as providing engineering support for the energy and industrial market.

Modcon Makina is a young manufacturing organization offering high-quality service packages for industrial facilities, which leverages cutting-edge technology and extensive production know-how with a special focus on carbon steel products.

Prodinox Metal is a company specialized in stainless steel manufacturing, also providing architectural and engineering of facade systems using different technical procedures, primarily focused on leading customers of different sectors such as construction, power, oil, gas, defence and chemicals industries.


The Turkish soundproofing sector

Türkiye’s industrial sector is currently witnessing a rapid growth, especially as regards manufacturing, construction, and energy production.

It is also observed a recent increase of the awareness among Turkish businesses about the essentiality of acoustic insulation to make industrial environments safer, enhance productivity, and decrease noise-related damages.

Against this backdrop, there is an expanding demand for soundproofing solutions designed to tackle noise pollution, also driven by the stricter regulations backed by the Turkish government.


The new company

Stopson Türkiye will therefore benefit from the extensive experience of each of the three players. This collaboration is expected to be a win-win situation for the companies involved with a view toward providing customers with products and services of greater quality and reliability.

Thanks to this partnership, Stopson Italiana’s will introduce its products to the Turkish market. At the same time, the new company will be an option for manufacturing acoustics and related components for Stopson Italiana’s customers at a global level.

We can now proudly combine our different know-hows and join forces into a single, stronger entity to meet all the customer needs.

How to effectively soundproof an industrial HVAC system: some key principles

An examination of the structural factors to take into account in order to tackle HVAC-related noise pollution in industrial facilities.

Industrial HVAC systems play an instrumental part to provide heating, cooling and ventilation to a wide range of facilities such as chemical processing plants, manufacturing facilities, power generation plants and water treatment plants.

They are normally larger and more complex than residential HVAC systems, which makes them also statistically at higher risk of becoming noisy spot.

As a matter of fact, these installations are inclined to produce loud sounds at the damage of the surroundings. It is therefore clear that all the facilities hosting these machines should need to adopt, willy-nilly, a soundproofing strategy in case the hearing comfort of the operating individuals is put in jeopardy.

The initial step of the approach implies the determination of the area where the HVAC systems is installed. Being placed outdoor means, for instance, be arranged for a specific solution over another.

Moreover, as anyone would expect, the location of the HVAC device determines the type of the HVAC equipment. For instance, components such as chillers, fans, cooling towers, and pumps fall within the outdoor HVAC equipment. On the other hand, components such as ducts, junctions, diffusers, and cooling coils are likely to be found inside facilities.

HVAC-related noise control can be engineered by employing two distinct classes of materials: absorptive ones, which naturally absorb sounds, reduce reflections from surfaces and decrease reverberation within spaces, and sound partitions or barriers, which reduce sound transmission between adjacent spaces through non-porous textures, generally recognized as good reflectors of sound.

Reducing noise transmission from outdoor machines requires, firstly, an accurate mapping process of noise propagation. Ventilation of buildings, enclosures and equipment rooms should be meticolously evaluated. Structural factors should be already considered when selecting HVAC equipment and while designing air distribution systems to minimize the noise. The overall design requires, a careful assessment of all the limitations of space, selection of fan, and aerodynamic pressure drops. The final objective is to eradicate the noise created by the flow of air or gas while simultaneously maintaining the flow itself and keeping the pressure drop minimal.

Three main cutting-edge soundproofing technologies provided by Stopson Italiana are suitable to HVAC systems: Acoustic Louvers, Intake Silencers and Acoustic Enclosures. These are indeed durable and easy-to-operate solutions to be integrated as noise control measures into the system design. A series of Silencers specifically designed for HVAC are a perfect fit for applications requiring maximum insertion loss (noise reduction), low static pressure drop, low maintenance, and quick delivery. They can be incorporated into the ventilation system and paired with the machine to fully soundproof it towards all directions.

Explore our news about Industrial Silencer applied to HVAC system to deep dive into the topic.

Stopson Italiana wishes you a Merry Christmas and an Happy and Safe New Year

Our 2021: new international projects, expansion of the product range within the marine sector, and a return to a face-to-face trade show.

Innovation and progress have been embedded in our DNA since 1965. In the last months, our departments are still growing in number.

Here below some highlights of our last year:

Back to Trade Shows

  • Enlit is the new unified brand for Clarion Energy’s Global Utility Week and POWERGEN series of events. This year the leading trade show in the POWERGEN sector was held in Milan, our city, and finally in attendance, in compliance with safety regulations. It was a pleasure to present the technological features of our soundproofing products, like Vent Silencers, Intake & Stack Silencers, and many more.


Expanding our offer for the marine industry

  • SilencERmarine is now part of Stopson Italiana’s assets.
    SilencERmarine is a recognized brand in the world of marine equipment and noise control, specializing in the manufacture of soundproofing systems for the luxury sector of the boating and yachting industry.

As 2021 draws to a close, we would like to wish our customers, communities, partners, and other stakeholders a Merry Christmas! We were proud to continue providing reliable, cutting-edge soundproofing solutions to our customers.

Keep following and supporting us, your trust is our strength.

Stopson Italiana wishes you a Merry Christmas and a Happy New Year

Another great year has passed re-confirming a growth trend for Stopson Italiana.

A slight recovery in oil price and general market demand is boosting our expectations for a brighter future ahead of us.

2017 has been a year of large investments for us in order to set up our Company for future growth: the acquisition of new calculation tools expanding our in-house capabilities to engineer complex projects, the implementation of technical documentation management system to support our ability and responsiveness to deal with most demanding Customers and project specs, the launch of SAP B1 ERP system scheduled for January 2018 are just a few examples of our enlarged platform to address next challenges.

Stopson Italiana remains grateful to all of our Customers who made that possible with their continuous support and trust and wishes you and your family a Merry Christmas and a prosperous 2018!

Gastech 2017

Stopson Italiana will exhibit at OMC 2017 and Gastech 2017

Two among the largest International Trade Show for Oil & Gas industry
Stopson will present its products of technological excellence within the Offshore Mediterranean Exhibition & Conference (Ravenna, IT), and Gastech (Tokyo). Two events that will bring together hundreds of companies and organizations from worldwide.
For all those attending, Stopson Italiana will make available its technical expertise to support any demanding requirements to develop new sound-proofing solutions in the Power Generation Industry and Oil & Gas.

Offshore Mediterranean Conference (OMC)
29-31 March 2017 | Ravenna ITALY

Gastech 2017
4-7 April 2017 | Chiba-Tokyo

ExxonMobil Singapore

ExxonMobil keeps expanding Singapore

A new refinery for blended lubricants to meet lower emission and raise fuel economy

Last February 16th, ExxonMobil Corp. has announced the expansion of its Singapore refinery to support the production of the company’s EHC™ Group II base stocks.

The aim is to develop the global supply of these products, enhancing the Singapore facility’s competitiveness. In facts, the project has been meant to enable customers “to blend lubricants that satisfy more-stringent specifications, help reduce emissions, and improve fuel economy and low-temperature performance“, ExxonMobil said.

On the other hand, Reuters published last week an announcement that a carbon tax on direct emitters is to be introduced from 2019. A strong signal that places Singapore – Asia’s main oil trading hub – in the way to moving towards a longer-term future dominated by cleaner technology and resources.

The ExxonMobil’s EHC product line has been designed to maximize the performance of all major automotive engine oil grades and to enhance the performance of finished lubricants used in multiple industries.

This expansion project represents the latest in a series of recent ExxonMobil investments in base stock production, including a previous expansion of capacity at the Singapore refinery in 2014, a recently-commissioned project at the company’s major integrated facility in Baytown, Texas, and introduction of Group II base stocks into European markets ahead of the anticipated completion of the new Rotterdam hydrocracker unit in 2018.

ExxonMobil released that a cogeneration project has started to improve energy efficiency and reduce emissions at the Singapore refinery. Construction is expected to begin during the second quarter of 2017 with completion anticipated in 2019.

How to Provide an Efficient Noise Propagation Control’s Infrastructure (ISO 11690-2)

The need for the companies to adopt a solid noise control policy has been widely covered in a recent article.

Regarding the control of the noise during its propagation – from the source to the receiver (generally the worker) – some or all of the following actions need to be considered meticulously, in order to set-up the most appropriate infrastructure within the plant:

  • Use of vent silencers (for valves and tanks), designed to reduce noise level of exhaust piping to the atmosphere for pressurized gaseous fluids.
  • Use of acoustic barriers (single walls), partial enclosures or full enclosure of the entire item of equipment.
  • Use of enclosures for noisy components on a machine.
  • Use of reactive or dissipative mufflers; the former for low frequency noise or small exhausts, the latter for high frequencies or large diameter exhaust outlets.
  • Use of in-line plenum chambers or lined ducts for air handling systems
  • Reverberation control – the addition of sound absorbing material to reverberant spaces to reduce reflected noise fields. Note that care should be taken when deciding upon this form of noise control, as direct sound arriving at the receiver will not be affected. Experience shows that it is extremely unusual to achieve noise reductions in excess of 3 or 4 dB(A) using this form of control which can be exorbitantly expensive when large spaces or factories are involved. In flat rooms the spatial sound distribution is of interest, see ISO 11690-1,-2.
  • Active noise control, which involves reflection, suppression or absorption of the noise radiated by an existing sound source by use of one or more secondary or control sources.

The commitment starts with a detailed analysis in order to ensure proper noise control measures for the facility design process. Three necessary steps in raw are accurately executed:

  • Field assessments Interpretation
  • Risks Mitigation
  • Reduction of noise control’s costs

All the analysis performed on noise and vibration problems are accomplished taking in account of noise control optimization’ costs, risk management from facility noise, complaints and regulatory compliance challenges.

The fully customized solutions realized by Stopson Italiana cover Oil and Gas, Power Generation, Marine and other industriesThe long-time maintenance assessments and long-term monitoring services are adopted to ensure full compliance over time.

Stopson Italiana is one of the Italian leading provider of innovative sound control solutions, noise impact model design and prediction.

In order to expand its staff, Stopson has recently open five new job positions in the following areas: Design Engineering, Project Engineering, Sales Engineer, and Quality Assurance-Control (QA-QC).
See more on Stopson Italiana CAREER Section.


Oil and Gas 360: the Trump ‘side effect’

From the stocks’ uncertainty to the pipeline’s manufacturing reestablishment: the new elected 45th US President keeps pushing to boost gas and oil outputs

“Making America ‘Crude’ Again”. This the buyword resounding like a commercial – and spotted by the newspaper – after the last new elected 45th US President Donald Trump’s speeches. How the Trump’s policy could affect the oil and gas market is still undoubtedly hard to sentence. However, barely hours after Trump had taken office, a revised White House website has declared its new found pro energy industry credentials.
That’s the way on which – after three days into his presidency – Trump gave his explicit backing to two controversial pipeline projects: Dakota Access and Keystone XL, providing American steel for their construction.

Nevertheless the presidency of Donald Trump, who made promises on the campaign trail to boost US oil and gas output and roll back regulations unfriendly to industry, is expected to be a stark policy departure from President Barack Obama, who spent much of his political capital over the past four years pushing efforts to combat climate change.

Furthermore, Trump reiterated his creed that pipeline makers use U.S. materials when they build projects in the United States, another sign that he will keep pressure on companies in the middle of the energy sector.

Crossing the boundaries, Mexican gasoline market reforms could influence U.S. gasoline export trends. In facts, the government is in the process of opening its gasoline and diesel markets to outside competition and replacing government-set prices with market-based prices. Last year, Mexico began allowing entities other than the state-owned company Petróleos Mexicanos (Pemex) to import gasoline and diesel and open retail stations. These changes followed previous energy sector reforms that ended Pemex’s upstream monopoly and opened the oil and natural gas sectors to foreign direct investment. Although Mexico is a large crude oil producer, it relies heavily on imports of gasoline from the United States to meet domestic demand. Therefore, the outcome of gasoline market reforms in Mexico may have significant implications for the sale of U.S.-produced gasoline.

The volume of gasoline trade between Mexico and the United States is significant to U.S. refineries. Over the past five years, U.S. exports to Mexico accounted for between 44% (2014) and 54% (first 10 months of 2016) of total U.S. gasoline exports. On a year-over-year basis, U.S. gasoline exports to Mexico increased by 71,000 b/d in 2015, with additional average growth of 75,000 b/d over the first 10 months of 2016, when U.S. exports to Mexico averaged nearly 390,000 b/d.

Based on projections in EIA’s January 2017 Short-Term Energy Outlook (STEO), natural gas prices are expected to increase in both 2017 and 2018. Rising natural gas prices could lead developers to postpone or cancel some of the upcoming power plant additions. Construction timelines for these plants are relatively short: more than half of the natural gas-fired generating capacity scheduled to come online in 2017 and 2018 was not yet under construction as of October 2016.
Stock and trading
On the New York Mercantile Exchange, light, sweet crude futures CLH7, +1.43% traded at $52.43 a barrel, down 20 cents, or 0.4%, in the Globex electronic session. Brent crude LCOH7, +1.05% on London’s ICE Futures exchange fell 9 cents to $55.14 a barrel. U.S. oil production now stands at 8.96 million barrels a day, according to the U.S. Energy Information Administration.

According to a BMI Research report, North America, the Middle East and parts of Asia will lead the recovery in oil and gas spending over 2017. The reports told that spending on oil and gas in North America is expected to raise by more than 17% this year.