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Asia Noise News Environment Uncategorized

Noise Pollution and Cardiovascular Diseases: A Growing Concern

Noise pollution is a growing problem in our modern world. It is the unwanted or excessive sound that can have negative effects on human health and well-being. In recent years, researchers have found that noise pollution can be linked to various health problems, including cardiovascular diseases.

A study conducted by the World Health Organization (WHO) showed that exposure to environmental noise can have adverse effects on public health. According to the WHO, more than one billion people around the world are exposed to high levels of noise, and this exposure can lead to a range of health problems, including cardiovascular diseases.

Cardiovascular diseases are the leading cause of death globally, accounting for nearly 18 million deaths each year. These diseases affect the heart and blood vessels and can result in heart attacks, strokes, and other health complications.

The link between noise pollution and cardiovascular diseases has been established through numerous studies. One of the most significant studies in this regard was conducted by the University of Oxford. In this study, researchers found that exposure to high levels of noise can increase the risk of heart disease by up to 50%. The study also found that noise pollution can increase the risk of stroke and other cardiovascular diseases.

So, how does noise pollution affect the cardiovascular system? The answer lies in the stress response of the body. When we are exposed to noise, our body reacts by releasing stress hormones like cortisol and adrenaline. These hormones trigger the “fight or flight” response, which can cause an increase in heart rate, blood pressure, and breathing rate. This response is normal and evolutionarily adapted to help us deal with threats and danger. However, chronic exposure to environmental noise can lead to prolonged stress response, leading to long-term damage to the cardiovascular system.

Environmental noise can also disrupt sleep, which is essential for the proper functioning of the cardiovascular system. Lack of sleep can lead to high blood pressure, impaired glucose tolerance, and other negative impacts on the heart and blood vessels.

Moreover, the impact of noise pollution on the cardiovascular system is not limited to adults. Children who grow up in noisy environments may be at higher risk of developing cardiovascular diseases later in life. Studies have shown that children exposed to high levels of traffic noise are more likely to have high blood pressure, even at a young age. This is particularly concerning, as high blood pressure in childhood can lead to a higher risk of developing cardiovascular diseases in adulthood.

It is important to note that noise pollution is not just limited to traffic noise. It can also come from sources like aircraft, industrial activity, and even household appliances. Therefore, it is crucial to take steps to reduce noise pollution in our environment. Governments around the world are taking measures to reduce noise levels, such as creating noise barriers, regulating noise emissions from industrial activity, and restricting nighttime transport.

Individuals can also take steps to reduce their exposure to noise pollution. This can include wearing earplugs or noise-canceling headphones, avoiding noisy environments, and choosing quieter modes of transportation. In addition, creating a quiet environment at home, such as using soundproof curtains or adding insulation, can also help reduce noise levels.

In conclusion, noise pollution is a significant public health concern that can have negative effects on the cardiovascular system. Chronic exposure to environmental noise can lead to a range of health problems, including heart disease, stroke, and high blood pressure. It is crucial to take steps to reduce noise pollution in our environment and to raise awareness about the importance of protecting our health from the harmful effects of noise pollution.

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Asia Noise News

Mumbai will observe ‘No Honking Day’ on Wednesday to reduce noise pollution

Mumbai Police’s Traffic Control Branch has declared June 14 to be “No Honking Day” to stop the practice of motorists using their horns needlessly, a top official said here on Monday. This is being done in an effort to reduce noise pollution and its detrimental effects on health.


“In addition to negatively affecting human health, unnecessary honking pollutes the environment with noise. We encourage drivers to participate in the “No Honking Day” by refraining from honking their horns, the officer said.


As per Rule 119 of the Central Motor Vehicle Rules, 1989, the Mumbai Traffic Police has also advised all drivers to check the horns on their cars.

According to the MV Act and the Environment Protection Act of 1986, “Action will be taken against those who indulge in needless horn blaring of their vehicles,” warned the police.

 

The Mumbai Traffic Control Branch also called upon all the drivers and riders in Mumbai city, barring ambulances, fire brigades and other on-duty emergency vehicles, to refrain from honking on June 14 and even other days as well.

Anti-noise pollution crusader Sumaira Abdulali of ‘Awaz Foundation’ has strongly welcomed the police initiative and said that the last time such an exercise was carried out in Mumbai was 17 years ago in 2006.

“This is the need of the hour. Awaz has done several sessions with the police on this menace and we have done studies on the ill-effects of honking without adequate reasons. We appeal to the police to ensure that it should not be only this Wednesday, but even all other days henceforth,” Abdulali told IANS.

She said that motorcycles are the worst noise polluters on the roads, touching as high as 110 decibels, and most other vehicles are in the range of 90-100 decibels which is a matter of serious concern, and since the fines for honking nuisance have been doubled, the law is in favour of the police.

Mumbai has an estimated vehicle population of around 43 lakh comprising two-wheelers, three-wheelers, cars, light and heavy motor vehicles, goods carriers, etc.

References

Canindia

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Asia Noise News Home

To solve the intractable issue of noise spats, a holistic approach is required

There may not always be an obvious resolution to neighbor disputes, which can be complicated.

A Tampines resident first noticed her neighbor making noises like hammering in the early morning and middle of the night during the Covid-19 pandemic in 2020.
The woman identified only as Amy said she was also bothered by sounds like running water and what appeared to be a creaking fan. At first she tried to ignore the noises, but as time went on they became more and more intolerable, interfering with her sleep and consequently her work.

Amy said she also complained to the Housing Board and town council about her neighbour, to no avail. According to her, her neighbour even ignored an order from the Community Disputes Resolution Tribunals (CDRT) to stop making noise.

In her latest bid to end the disturbance, Amy, who quit her job in the video production sector in 2022, said she is applying for a special direction for her neighbour to comply with the CDRT order.

Her case, which will be heard in May, illustrates how intractable neighbour disputes over noise can be, and the need for more effective ways to resolve them.

The authorities have taken steps to address noise spats over the years. In 2015, the Police Force Act was amended to allow for the appointment of community wardens with the power to take down particulars, advise people to keep their noise level down and deliver composition notices on behalf of the police.

But the number of complaints involving noise issues continued to climb, and soared during the Covid-19 pandemic when many people worked and studied from home.

In 2017, HDB received 3,493 complaints of disputes between neighbours. The number of complaints jumped by almost eight times to 27,600 in 2022, or 2,300 on average per month.

In March, Senior Minister of State for National Development Sim Ann announced that the Municipal Services Office (MSO) will form a unit to help resolve protracted and egregious disputes between neighbours. This group will be given the power to investigate disputes and stop certain nuisance behaviour, she said.

Second Minister for Law Edwin Tong had also said that cases where noise is used as a weapon to disrupt the peace among neighbours will come under the new legal framework on mandatory mediation for community disputes.

When noise disputes occur, first responders such as HDB and grassroots leaders will encourage neighbours to talk and try to resolve the issue amicably.

Some residents turn to the Community Mediation Centre (CMC), where trained volunteers help to mediate sessions between the parties involved. Some may opt to lodge a magistrate’s complaint to start a private prosecution, if they believe their neighbour has committed a criminal offence against them.

The magistrate will then decide if the case is worth pursuing and direct the police to investigate. In the process, the magistrate may issue a warrant for the alleged offender’s arrest.

Apart from a magistrate’s complaint, people can turn to the CDRT, which was set up to handle such disputes.

In 2022, there were 126 claims filed with the CDRT involving excessive noise, down from 150 cases in 2021. However, the figure was still more than double the 61 claims filed in 2019, before the Covid-19 pandemic struck.

One of the top noise concerns is inter-floor noise, which includes sounds of furniture being dragged, rolling marbles and doors being slammed.

Other avenues for recourse include applying for voluntary mediation or for a protection order under the Protection from Harassment Act.

In a high-profile case reported by The Straits Times in 2020, a couple was barred from their Bukit Panjang flat for a month after they were found to have breached an earlier court order to stop disturbing their neighbours in the unit above. It was the first time that the CDRT under the State Courts had issued an exclusion order.

The couple eventually sold their flat, ending a protracted dispute that began in 2017.

In another severe dispute, the residents of a Punggol HDB block had to endure disturbances from a neighbour who, among other things, allegedly splashed oil at their doorsteps and left a bloody pig’s ear on a shoe rack.

Her behaviour caused many residents to fear for their safety. Some even installed closed-circuit television cameras in their homes to protect themselves.

This case was troubling because even though reports of her behaviour had been made since 2014, the matter was resolved only in 2021, when she moved out of her flat in Punggol.

While there are various agencies and avenues for recourse available, it seems that none of them is able to truly address the serious disputes. The outcome of the two cases showed that the issues were resolved only when either party moved out.

Clearly, there needs to be a more effective way of resolving neighbourly disputes, especially those involving noise.

Statistics have shown that mediation is highly effective in helping neighbours work things out, with 80 per cent of disputes that end up at the CMC resolved.

However, residents have reported difficulties with this option as their neighbours do not always turn up for mediation, and going to court or tribunals can be a tedious and expensive process.

Community mediation is generally voluntary, and currently, there are no consequences for disputing parties who fail to attend mediation, said a Ministry of Law spokesman.

In cases where a CDRT claim has been filed and the respondent fails to turn up for the hearing, the CDRT may grant a CDRT order in the absence of the respondent. But a breach of the initial CDRT order is not a criminal offence, added the spokesman.

As a result, residents whom ST spoke to feel that their only option is to sell their flats and move away.

It is important to recognise that neighbour disputes can be complex and multifaceted, and there may not always be a clear solution.

While the Government continues to encourage good neighbourly communication and tolerance, the new MSO unit will now intervene at appropriate junctures for egregious disputes.

However, the unit must be given sufficient powers and teeth in order to stop the wilful weaponisation of noise by neighbours.

References

straitstimes

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Asia Noise News Home

Hong Kong man turns tables on noisy neighbours with sweet-sounding device that blasts out tit-for-tat racket

  • Incensed man has been plagued by late-night and early morning noise from his upstairs neighbours for months
  • After an official warning from the property’s management fell on deaf ears, the man turned to a ‘revenge’ device which blasts amplified noise into adjacent flat

An exasperated Hong Kong man has found a novel way to take revenge on his noisy neighbours, and it goes by an unlikely name.

The city’s cramped living conditions mean noise pollution is a common problem and recently an enraged citizen – who had complained 14 times about his noisy neighbours to no avail – found a cutting-edge way to fight back.

It came in the shape of a vibration speaker called “Little Cutie”.

On a Facebook group called “Neighbourhood Noise Alliance (Hong Kong)”, which has more than 8,000 members, the angry man explained that he had been suffering from noise from his upstairs neighbours for a long time.

The enraged neighbour had complained to the property management company 14 times to no avail. Photo Shutterstock

He said the family of four living upstairs never go out except to take their children to school.

As a result, the children have been “walking from one end of the apartment to the other, playing with balls and sometimes jumping up and down”, making his life unbearable.

The poster said that sometimes he was woken up at 7am by the sound of running.

 

After investigating the situation more closely, he discovered that the two children upstairs were playing basketball and jumping around in the apartment, and their father failed to stop them.

After 14 complaints to the property management company, the noisy family were sent a warning letter, but it had no effect on their behaviour.

The “Little Cutie” device blasts back revenge noise at amplified decibels. Photo: Facebook/Neighbourhood Noise Alliance (Hong Kong)

In desperation, the man approached the above-mentioned Facebook group for help where it was suggested he seek the services of “Little Cutie”.

An online observer said: “The only solution is to fight back with ‘Little Cutie’ and be crazier than them.”

 

“Little Cutie” is a vibration device that, when attached to a connecting ceiling or a wall, will create noise several times louder than that it detects in the adjoining dwelling.

 

The poster decided that whenever the neighbours made a noise, he would activate “Little Cutie” to blast back heavy bass music.

Under Hong Kong’s noise control laws, it is an offence for a person to make or cause a noise in a dwelling or public place between 11pm and 7am or at any time on a public holiday.

According to the Hong Kong Environmental Protection Department, in 2021, the department issued 1,185 warnings over neighbourhood noise due to hawking activities.

References

South China Morning Post scmp.com

Categories
Asia Noise News Environment Home Noise and Vibration Product News Uncategorized

Songkran Celebration – Noise complaints during holidays

Punyakorn, April 2023

Geonoise (Thailand) Co., Ltd

The previous week is a week of celebration in Thailand for the Thai New Year or also known as “Songkran Days”. The celebration usually lasts for three days from 13 -15 April every year. This celebration is also well known for the way people celebrate by adapting the traditional activity to a water festival or water fights. This year is also a little bit special after the government put on a break during the COVID-19 situation. There is much positive feedback from the people that finally things tend to turn back to the normal conditions that they can celebrate, and many festivals are now allowed again.

There are many well-known areas or streets where most Thai and foreigners go to enjoy the festival and the water fights, but some might not be so convenient to travel across the city there. That’s when people need to find their way of celebrating!

Many clips on the internet show how people are having fun at their own houses, most people will have a small water station in front of their home where their neighbors can join when they are passing by. Some might make it bigger and more fun, having loudspeakers and playing some partying music.

However, this might be the start of the complaints….

What makes party music might be a disturbance more than a fun to the neighbor?

Party music is made to make people feel fun and enjoying. That is why most party music contains a lot of heavy beats and low bass sounds. These sounds are called ‘low frequency’ in a more engineering way. Normally we are not good at hearing these low frequency, but our ears are smart, it detects these low frequency a lot better when the sound is loud enough and when it plays in beat (or called ‘impulse’ by engineers). These low frequencies are also good at traveling long distances and having big waveform, this makes low frequency can pass through a wall without taking so much effort!

What should we do to prevent complaints?

If you’re planning to have a party again next year with some music in the backyard, you might try to keep the volume a bit lower and not boost the bass of your speakers. Second, be careful about your party time, after 10 pm is commonly known as nighttime when people need to rest, they are more sensitive to noise during this time. There are laws and regulations from the government protecting people’s health, so the laws are more sensitive during this time of day as well. Third, a small party room in your home is also a good idea! These days there are several companies that can help you with the design of a soundproof room with a good sound system.

What should I do if my neighbors are making noise?

Keep in mind that the laws are protecting you! You might try to contact the police officer in your area and not engage the neighbor by yourself. The police can help stop the noisy activity. Another regulation is by the Department of Public Health of Thailand, contact your local authorities to stop the disturbance activity. The laws protect your right to have good health and proper rest.

Thai Ministry of Justice provided an infographic for the related laws that emitting loud noise and creating disturbance can lead to a fine from 1,000 baht – 10,000 baht or imprison not exceeding 1 month (depending on the law section).

Follow this link: https://www.moj.go.th/view/75639

Prevent noise in the long run: interested in improving your home acoustic insulation?

You may need a professional acoustic consultant to find the most effective way, especially when you are dealing with low-frequency noise. This noise is really good at traveling through structure, normal designs or materials might not work at their best performance without proper acoustic designs.

Celebrating Songkran in Thailand next year?

Feels the fun and enjoy the festival for three days long here in Thailand.
But after this, you might want to keep in mind and care for others who might not celebrate the festival as well.

Happy Songkran Days!

References

Department of Health, Ministry of Pubic Health (2560). พระราชบัญญัติการสาธารณสุข พ.ศ. 2535 หมวด 5.

กฎหมายน่ารู้ ตอนที่ 388 : เพื่อนบ้านทำเสียงดังเดือดร้อนรำคาญ เสี่ยงคุก 1 เดือน ปรับ 1 หมื่น. (2022, September 28). Retrieved from MINISTRY OF JUSTICE OF THAILAND: https://www.moj.go.th/view/75639

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Asia Noise News

1st ASEAN INTERNATIONAL ACOUSTIC CONFERENCE

The First ASEAN International Acoustics Conference. will be held online on the 9 May 2023, Tuesday.

 Theme of the conference: International Noise Awareness.

Organiser:  the ASEAN Acoustics Commission comprising the four acoustical societies and associations of Indonesia, Malaysia, Singapore and Thailand.

 Abstracts deadline:   15 April 2023

Length of abstracts:   limit of 300 words

Link for subscription

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Asia Noise News

Singapore: Noise-induced deafness incidents that were reported tripled from 168 cases in 2021 to 624 last year

SINGAPORE — The number of reported incidents of noise-induced deafness in the workplace spiked sharply from 168 cases in 2021 to 624 last year mainly owing to more awareness of the condition and greater surveillance.

This was according to the latest Workplace Safety and Health Report, which also noted that a mandated period of heightened safety from September last year led to a drop in workplace fatalities.

However, there was an uptick in workplace major injuries, the report added.

Here are some of the key findings from the report, which was released by the Ministry of Manpower (MOM) on Tuesday (April 4):

NOISE-INDUCED DEAFNESS

The report said the number of incidents of noise-induced deafness had been generally trending downwards from 498 cases in 2015 to 168 cases in 2021.

However, MOM attributed the recent surge to 624 cases in 2022 to ongoing enhanced workplace health surveillance (WHS+) efforts, as well as increased awareness among doctors and employers, resulting in more reporting of such cases.

In 2021, MOM rolled out the WHS+ under the national 10-year Workplace Safety and Health (WSH) 2028 strategy to minimise hazards that lead to occupational diseases, including noise-induced deafness.

Responding to TODAY’s queries, a MOM spokesman said that under WHS+, workplaces with high noise levels are required to adopt upstream risk controls to reduce workers’ noise exposures and put in place effective Hearing Conservation Programmes to manage noise hazards at workplaces.

The spokesman added that MOM is also continuing to increase the number of workplaces under WHS+ as well as collaborating with the Workplace Safety and Health Council, an industry-led statutory body, to increase awareness and implementation of Hearing Conservation Programmes.

“Through these efforts, there was greater awareness in reporting of noise-induced deafness amongst doctors and employers which contributed to the increase in noise-induced deafness numbers.”

The MOM report also highlighted that noise-induced deafness was the leading cause among 1,052 occupational diseases recorded last year, followed by work-related musculoskeletal disorders with 340 cases.

The manufacturing sector was found to be the main contributor to noise-induced deafness cases, accounting for 69 per cent (430 cases) of the total number of cases, followed by the marine sector with 8 per cent (50 cases).

The report did not provide information on the sectors that contributed to the remaining noise-induced deafness cases.

The MOM spokesman said that ​​​​​​manufacturing and marine sectors have been the top contributors for noise-induced deafness cases over the years, due to noisy processes that are present in both industries.

“Some noisy work processes include metal sheet stamping, grinding, drilling, grit blasting, as well as the use of powered tools and machinery.”

Responding to TODAY’s queries, Associate Professor Chui Yoon Ping of Singapore University of Social Sciences said MOM has been tracking noise-induced deafness for many years. It was a notifiable condition as far back as 1975, she said.

The deputy dean of the university’s College of Interdisciplinary and Experiential Learning said that while noise-induced deafness is incurable, it is preventable.

Source

 

 

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Asia Noise News Environment

Da Nang restaurants fined, suspended for blasting loud music

Three restaurants in Da Nang (Vietnam) were fined up to VND70 million ($2,975) and two of them were also suspended for blasting music too loud.

Police of Lien Chieu District on Saturday said the Victory, Max Beer Garden and Idol Food&Beer restaurants on Hoang Thi Loan Street violated noise pollution protocols by blasting music that was too loud.

The Max Beer Garden restaurant was fined VND70 million and had its operation suspended for 4 months. The Idol Food&Beer was fined VND50 million.

The Victory got fined VND50 million for a second time and saw its operation suspended as well. Its owner, 38-year-old Phan Duy Tan, was also fined VND12.5 million for allowing repeated violations at his restaurant.

Hoang Thi Loan Street is popular for its numerous restaurants, bars and dance clubs, often blasting loud music throughout the night.

Da Nang’s environmental police department said that since 2019, the unit had dealt with 18 cases of noise pollution violations and fined a total of VND232 million.

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Asia Noise News Building Accoustics Environment Uncategorized

Importance of acoustics in office space

Office – traditionally known as a place for work, means more than just that in this modern era. Today, apart from being used for conventional office activities like reading, writing, or computer works, office is also the space for open innovative discussions, private meetings, business collaborations and a venue for office members to connect and build strong peer relationships. Certain offices even provide a space for entertainment purpose so that employees can have fun to destress from work.

Notice the connections between all the activities that can happen in the office? Each of them involves different levels and types of noise. This is when office acoustics comes into the picture.

Investing into the acoustics design of office spaces can be more important than what you may think it should be. High noise levels in the office have been one of the main complaints among employees, as it can significantly affect their work performance and productivity. Noise can come from the activities like keyboard-clicking, printing noise, or low frequency hums from office equipment like printers or computers. With high noises, conversations in the office will be difficult, such that employees will end up having to raise their voice while talking – eventually making things worse.

It is therefore imperative to focus on the office acoustics, especially for the following:

  1. Effective communication

Having the background noise under controlled in a office will ensure speech clarity during conversations, be it among employees, or when talking to clients.

  1. Employees’ wellbeing

Long exposure to high noise will cause increase in both physical and psychological stress levels among employees, leading to poorer productivity and communication. Prolonged stress can possibly cause harmful health effects, such as headache, high blood pressure, or increase in heart rate etc.

  1. Privacy

It is often required to have one-to-one meetings for highly confidential topics in the office, hence it is important to have spaces that offer sufficient privacy to prevent conversations cannot be overheard.

  1. Work performances

As mentioned in point 2 as well, noisy environments will cause interruptions during work, leading to difficulties in focusing on work. This will thus influence the employees’ wellbeing, linking back to point 2.

Now that the importance of office acoustics have been known, are there any ways to treat the noisy office environment, or even better…avoid it?

The acoustic quality of an office, or room in general, can be determined by doing reverberation time (RT) measurements. RT is defined by the time taken for reverberation to decay, where typically shorter RT is preferred for better speech intelligibility, as there will be less reverberation, or in layman terms “echo” that exists in the room. High reverberation is normally due to the hard structural surfaces that offices are built with, such as concrete, glass, plaster etc. To reduce the RT, it is recommended to install sound absorbing materials like acoustic ceilings, acoustic wall panels, thicker carpets/curtains or other similar products in the office. The absorption performances of these products can be defined by finding out the sound absorption coefficients (α) of the material, which should be already stated in the datasheets by manufacturers. Sound absorption is relatable to sound reflections of a room.

Reverberation control can then influence the speech intelligibility of a room, which can be measured as the Speech Transmission Index (STI), or speech to noise ratio (SNR). The higher the SNR or STI, the better the speech intelligibility. According to the rule of thumb, SNR should be essentially at least 10-15 dB for good speech intelligibility, which means that the speech should ideally be 10-15 dB above the background noise to be clearly heard. However, to meet the goal for privacy, it should be the other way round, where SNR should be as low as possible.

On the other hand, sound insulation, sometimes known as attenuation, associates with the sound transmission control between adjacent rooms. The purpose of having sound insulation is to achieve better privacy by effectively blocking noise travelling from one room to another. Similar to sound absorption, sound insulation of a product can be graded using a single figure rating called Sound Reduction Index (R). Sound transmission can happen when sound passes through structures like partitions/walls/floors/ceilings. Sound can also transmit through hollow elements in the building like ventilations, ducts, pipes, claddings etc. Therefore, it is important to design the interior carefully and ensure that the construction of the building is done properly to avoid any unnecessary costs for remedial work in the future.

As much as the interior aesthetic of office space should be the key of design, acoustics should not be neglected as well, because it will strongly affect the users’ experience while working or carrying out tasks in the office space. In fact, with the variety of acoustic treatment products available in today’s market, it is definitely possible for both aesthetic and acoustics to be taken care of without sacrificing either, especially when interior designers often can work with acoustic consultants nowadays. Hence, do consider to put in more effort in the soundscape design of your workspace, for the better wellbeing of both you and your fellow workmates.

 

REFERENCES:

https://www.barbourproductsearch.info/FIS-Acoustic-Guide-2015-file100897.pdf

https://www.workspacedesign.co.uk/

Categories
Asia Noise News Uncategorized

Control Valves Noise

The noise generated by control valves is a result of the turbulent flow of fluid through the valve and the pressure drop across the valve. As the fluid passes through the valve, it experiences sudden changes in direction and velocity, which can create turbulence and vortices that generate noise.

When the pressure of the liquid flowing through the valve drops below its vapor pressure, bubbles can form and collapse rapidly, creating shock waves that generate noise. This formation and collapse of vapor bubbles in a flowing liquid is called cavitation.

The severity of cavitation noise depends on several factors, including the pressure drop across the valve, the fluid properties (such as density and viscosity), and the valve design. Some common methods to reduce control valve cavitation noise include:

Increasing the pressure drop across the valve: This can be done by installing a pressure-reducing valve upstream of the control valve. By reducing the pressure upstream of the valve, the pressure drop across the valve is reduced, which can reduce the likelihood of cavitation.

  1. Increasing the valve size: A larger valve size can reduce the velocity of the fluid flowing through the valve, which can reduce the likelihood of cavitation.
  2. Using a different valve trim: The valve trim is the internal components of the valve that come into contact with the fluid.
  3. Using a different trim design, such as a multistage trim or a cage-guided trim, can reduce the likelihood of cavitation.
  4. Using a different valve material: Some valve materials, such as hardened steel, can be more resistant to cavitation than others.
  5. Adding a noise-reducing insert: A noise-reducing insert, such as a diffuser or an orifice plate, can be installed downstream of the valve to reduce the noise generated by cavitation.

It is important to note that while these methods can reduce the severity of cavitation noise, they may not eliminate it entirely. In some cases, additional noise mitigation measures may be necessary, such as installing a sound barrier or using ear protection.

The noise generated by control valves can be problematic for a number of reasons. For example, excessive noise can be a nuisance for workers or occupants in a facility, and it can even be a safety hazard if it interferes with communication or causes distraction. Noise can also be damaging to equipment and structures if it causes vibrations or resonance.

The noise level of control valves can be calculated using several methods, including empirical equations, computational fluid dynamics (CFD) simulations, and experimental measurements. Here are some common methods:

  1. Empirical Equations: Empirical equations are mathematical formulas that relate the noise level of a control valve to its flow rate and pressure drop. One such equation is the Masoneilan-Kates equation, which is commonly used in the industry. This equation is:

Lp = K1 + K2 * log10(Q) + K3 * log10(P1-P2) + K4 * log10(Q) * log10(P1-P2)

where Lp is the sound pressure level in decibels (dB), Q is the volumetric flow rate in cubic meters per hour (m3/h), P1 is the upstream pressure in kilopascals (kPa), and P2 is the downstream pressure in kPa. K1, K2, K3, and K4 are constants that depend on the valve size, type, and characteristics.

  1. Computational Fluid Dynamics (CFD) Simulations: CFD simulations use computer software to model the flow of fluids through a control valve and predict the resulting noise level. These simulations can provide detailed information about the flow patterns and turbulence that cause noise. However, CFD simulations require significant computational resources and expertise to perform.

 

  1. Experimental Measurements: Experimental measurements involve installing a control valve in a test rig and measuring the noise level using a sound level meter. This method provides direct, accurate measurements of the noise level but may be time-consuming and expensive.

Overall, the choice of method depends on the accuracy required, the resources available, and the expertise of the user.

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