Udon Thani: Relief measures including a plan to move a training base for the Thai and Singaporean air force F-16 fighter crew to Nam Phong airbase in Khon Kaen province in the next 3-4 years is being drawn up.
The move is to help locals living in the vicinity of the Royal Thai Air Force (RTAF)’s airbase in Udon Thani who have complained about aircraft noise, a seminar was told on Friday.
Authorities from the House Committee on Foreign Affairs, the RTAF, the Ministry of Natural Resources and Environment, and locals were invited to the city meeting to discuss a recent rise in noise pollution, particularly during take-off and landing.
Gp Capt Wisarut Chanthapradit, commander of the RTAF’s 23rd air wing, said nobody was sitting idly by following complaints from those affected in the northeastern province.
Plans to move the Thai and Singaporean air force facility to Nam Phong district in Khon Kaen province in the next 3-4 years are already advancing at pace.
Gp Capt Wisarut said that normally only four fighter jets would be in service at this time of the year; there were already a total of 12 jets involved in this year’s specially arranged joint training.
Sarawut Petchpanomporn, Pheu Thai MP for Udon Thani and president of the House committee, said it was a second trip for members to verify the credibility of the complaints following an earlier visit.
While cautiously welcoming the decision to relocate, Mr Sarawut also called on the combined force to offer aid to those affected by the extra air traffic.
Sayan Meekaew, chief of the environment quality control division of the Environment Office, said harmful noise levels had been recorded in three areas and hoped the RTAF would help pay for treatment for locals.
After tolerating what she claimed were sounds of dragging furniture and children running and jumping from her neighbour upstairs for about three years, her health deteriorated from being sleep-deprived and she had to stop working for six months.
The customer service officer, who wanted to be known only as Jessie, 37, told The Straits Times that she decided to give up and fork out $1,200 to rent a bedroom in a landed house elsewhere with her husband last month, as she could not take it anymore.
“Spending the money is worth it as it buys me peace. I can now sleep properly, my blood pressure has gotten better, and I can focus on my job now,” she said.
Jessie, who still owns her Housing Board flat in Yishun, took her case to the Community Disputes Resolution Tribunal (CDRT) in July 2020 after three failed attempts at mediation through the Community Mediation Centre (CMC).
She claimed her neighbours quietened down for about three weeks after the session, before the noise started to pick up again.
Jessie’s case was among 221 applications that were filed with the CDRT in 2020. There were 237 applications in 2021, Minister for Home Affairs and Law K. Shanmugam said in response to a parliamentary question on Feb. 18.
HDB has also seen an uptick in feedback relating to noise from residents’ activities, including renovation noise.
Such cases went up by about 25% to 3,200 cases a month in 2021, compared with 2,500 cases a month in 2020.
This is likely due to work from home arrangements, coupled with the resumption of renovation activity in June 2020, said National Development Minister Desmond Lee in response to a parliamentary question on Feb. 14.
Jessie, who worked in an office, claimed the noises from her neighbour’s young children would get worse after 10 p.m. and carried on until past midnight. When it stopped, noises from pushing furniture would begin.
The distress from not being able to sleep affected her at work.
She said: “I’d go to work and sleep in the office. I got quick-tempered, I started to scold customers and cry at work — I couldn’t control myself. I never behaved like that before, and it scared me.
“I couldn’t go on like this any longer and I left my job.”
Affecting mental health Annabelle Chow, principal clinical psychologist at Annabelle Psychology, said noise disturbances could result in poor quality fragmented sleep — when a person wakes up several times a night — and could affect their mental well-being.
“It increases daytime sleepiness, tiredness, annoyance, mood changes, and decreases cognitive performance,” she said.
Jessie was also prescribed medication — sleeping pills, antidepressants and propranolol, a medicine that treats high blood pressure, anxiety, and migraines.
Adrian Wang, a psychiatrist who runs his own practice at Gleneagles Medical Center, said that prescribing medication like antidepressants is common to regulate anxiety while patients look for a longer-term solution.
“Mental health is tied to physical health. If your sleep is poor and stress levels are high, it affects your blood pressure, digestive processes, and can cause tension, headaches, or anxiety attacks,” he added.
Jessie landed a job in the same line, which she started when she moved out last month. She and her husband are also in the process of selecting a build-to-order flat, which they applied for last November.
She said of her Yishun flat: “I thought this would be our ‘forever home,’ after renting for about three years before moving in. I love this unit, and I’m sad I’ll have to let it go.”
HDB advises those facing neighbour disputes to “communicate with your neighbours politely, listen to them and be willing to compromise” before seeking mediation services, according to its website.
The current quiet hours — where residents are advised to keep their volume levels low and avoid carrying out drilling and hammering works are between 10:30 p.m. and 7 a.m.
A private tuition teacher who wanted to be known only as Ng, 47, said she was polite when she approached her neighbour upstairs to tell them about the alleged heavy footsteps and dragging noises she heard.
“They said I was crazy and shut the door,” she said, adding that the noise, which occurs in the day, was disruptive.
But Ng is hesitant to apply for mediation through the CMC or CDRT.
“To bring the matter up to that level, wouldn’t it strain relations? It’s a last resort and I doubt the chances of an effective resolution,” she said. “I’ll just tolerate it.”
But in another case, Madam Chia, 46, said that bringing her issue to CDRT was the only avenue she had, as her neighbour upstairs refused to attend mediation and was adamant the stomping and running noises she allegedly heard did not come from their children.
“The neighbour even posted on our estate’s Facebook group that they were the ones being harassed,” the customer service officer added. The proceedings are still ongoing.
Wang advised people enduring noisy neighbours to explain the situation calmly to them.
“If the problem is not solved, seek help from authorities to mediate – don’t take matters into your own hands,” he said.
Singapore noise nuisance
In a letter to ST’s Forum page published on Feb. 21, an ST reader suggested a demerit system for recalcitrant noisy neighbours where HDB compiles complaints from residents about a specific unit.
HDB should issue the unit a warning letter when the complaints reach a certain number, the reader said, adding that the number of warning letters should be considered when the noisemaker applies for another flat or for services under HDB.
In the United Kingdom, noisy residents can be issued a noise abatement order. If they break the order, they can be fined up to £5,000 (S$9,000).
But criminal lawyer Amolat Singh said the demerit system is not workable as it may punish innocent residents living in the same home.
“If it’s up to the number of complaints, there is no avenue for a person to clear their name,” he said.
Singh noted that offenders who contravenes a Magistrate’s Court order to abate the nuisance can face a fine of up to $2,000 under the Miscellaneous Offences (Public Order and Nuisance) Act, but these are extreme cases.
“The remedy lies in educating people. We are a very densely populated country, and we must be a bit more sensitive,” he added.
Still, Jessie hopes more can be done.
She said: “There are many people who are in the same situation I was in, and we complain and give advice to each other on social media.
“Others may not have the means to move out like I did, so I really hope the Government can do more about this.
About 63,000 residents of Pyeongtaek will receive monthly compensation for noise pollution coming from a military airport in the city, officials said Monday.
According to the government of Pyeongtaek, a city about 70 kilometers south of Seoul, the residents of 10 administrative units, including Sinjang and Paengseong districts, will receive monthly compensation from August under the military noise pollution compensation act which took effect last year.
compensation for aircraft noise korea
South Koreans and foreigners who have been registered as residents of the districts between Nov. 27, 2020, and Dec. 31, 2021, are eligible for compensation application.
A monthly settlement of 60,000 won (US$50.30) will be provided per resident living in an area suffering noise pollution of 95 wecpnl or higher, 45,000 won for pollution of between 90 wecpnl and 95 wecpnl and 30,000 won for pollution of between 80 wecpnl and 90 wecpnl.
Wecpnl is a comprehensive unit measuring aircraft noise levels.
The city’s deliberation committee will review the applications and deliver the results by May, officials said.
With all the development, industrial activities and community activities in Indonesia, noise has become one of the problems that arises in some places in Indonesia. Indonesia already has some regulations, guidelines, and standards to safeguard the noise levels. This is important mainly to support a healthy environment for the people, and also to improve budgeting certainty of projects that will produce noise during their operations.
The following are the regulations, standards and guidelines related with environmental noise in Indonesia.
Environmental Noise Regulations
Regulations regarding environmental noise generally can be categorized into two types which are emission regulation and immission regulation. Emission regulations regulate how much noise can a noise source produces noise, while immission regulation regulates how much noise can a receiver or area receives noise.
Examples of noise emission regulations in Indonesia are:
Decree of Minister of Environment and Forestry No. 56 year 2019 (P.56/MENLHK/SETJEN/KUM.1/10/2019) regarding noise limits of new types of motorized vehicles and in production M category, N category, and L category.
Decree of Minister of Transportation of Republic of Indonesia No. PM 62, year 2021 regarding civil aviation safety section 36 regarding noise standard dan type certification and aircraft airworthiness
The two ministerial decrees above regulate how much noise can be produced by vehicles that are used on road and aircraft that can operate within Indonesian territory.
The regulation that regulates environmental noise level at the receiver is:
Decree of Minister of Environment No. 48 year 1996 about noise level limits
The decree states the noise limits that are allowed for the receiver according to its function – for example for residential area, the noise limit is 55 dBA and for industrial area 70 dBA. More details on the following link: https://www.konsultasi-akustik.com/en/environmental-noise-measurement/
Beside the regulations above, there are other requirement such as one written on Government Regulation (PP) No. 36 year 2005 regarding implementation rules of the Law No. 28 year 2002 regarding buildings. One of the points require noise reduction means for toll roads in residential area or existing city centers.
Guidelines regarding Environmental Noise
Beside the regulation, there are some technical guidelines that are written by Ministry of Public Works as follows:
Technical guidelines Ditjen Bina Marga No. 36 year 1999: Noise barrier planning guidelines In these guidelines, criteria to categorize area as safe, moderate and high risk are given. Moreover, the guidelines also state measurement techniques for measurement beside road and common type, shape and material of noise barriers.
Construction and building guidelines Pd T-10-2004-B: Road traffic noise prediction.
These guidelines adopt calculations from Calculation of Road Traffic Noise (CoRTN, UK, 1998) which contain noise calculation method based on traffic volume and speed. There are also corrections for heavy vehicle percentage, speed, gradient and road surface. From this calculation, propagation to receiver can be calculated considering distance, screening, reflection and angle of view.
Construction and building guidelines Pd T-16-2005-B: Mitigation of road traffic noise
The guidelines lay out methods to mitigate noise from traffic which is based on measurement (which are written on Permen LH No. 48 year 1996 and guidelines No.36 year 1999 above) and can also be based on predictions (Following construction and building guidelines Pd T-10-2004-B)
Environmental Noise Standards
Beside the regulations and guidelines, there are Indonesian National Standard (SNI) document that are written by National Standardization Body (BSN) that are related to environmental noise:
SNI 19-6878-2002 – Road traffic noise test L10 and Leq This standard contains test method which state testing procedure and data processing steps to calculate LA to L10 and Leq
SNI 8427:2017 – Pengukuran tingkat kebisingan lingkungan This standard contains measurement method that is similar to Kepmen LH No.48 year 1996 which is to measure noise samples for 10 minutes across 24 hours period. Noise levels then can be calculated based on its time slice which are Ls (daytime noise), Lm (nighttime noise), and Lsm (day-night noise, with 5 dB penalty for nighttime).
In the Southeast Asia region especially, acoustic properties of residential buildings are often neglected by designers, developers, contractors, and even home buyers. Noises from both internal and external environments affects occupants’ daily lives, causing nuisance which can strongly deteriorate one’s living quality as a long-term effect. In this article, we will investigate building/room acoustics, and the actions that can be undertaken to improve the acoustical environment inside a building.
Room acoustics
In general, the acoustics of rooms can be divided into two groups: low frequency and high frequency. Sound in rooms can be highly affected by the reflective properties of the surfaces in the room. This is because multiple reflections may occur if the room surfaces are highly reflective, which then leads to a reverberant field in addition to the direct field from the source especially at higher frequency range. Therefore, at any point in the room, the overall sound pressure level is influenced by the energy contained in both the direct and reverberant fields (Crocker, 2007).
Sound transmissions in buildings
Sound can be transmitted within a building by transmitting through air in the spaces bounded by walls or roofs/ceilings, known as airborne transmission. Another way would be through structural transmission through the structural assemblies of the building, or impacts.
Airborne sound originates from a source that radiates sound waves into the air, which would then impinge on the building surfaces. A good example of airborne sound will be speech, or music from a television or loudspeaker. On the other hand, impact sound is being generated when an object strikes the surface of a building. The commonly heard impact sounds that we can hear in buildings are footsteps, furniture-dragging sounds, cleaning, and other equipment that is used directly on the floor surfaces. To overcome these noises, good sound isolation should be considered for all the possible paths for sound and the junctions between walls and floors, not just at the direct path through common wall or floor.
Sound insulation – airborne and impact
It is imperative to consider the control of airborne and impact sound transmission through the building elements like walls, ceilings, or floors, as stated above. In this case, sound insulation methods will be crucial. Different methods can be implemented for airborne, impact and flanking sounds (Crocker, 2007).
For airborne sound, insulation can be applied at any building element. This is because when sound hits on a surface, a very small fraction of the incident energy will be radiated from the other side. The sound transmission loss (TL), which is the ratio of the incident sound energy relative to the transmitted sound energy is typically measured. TL can be expressed in decibels (dB), and it is sometimes known as sound reduction index (R) in European and ISO standards. The elements to be used in buildings for sound insulation are measured in accordance with standards, where the commonly seen method would be the two-room method. A test specimen would be mounted between a reverberant source room, and a receiver room such that the only significant path for sound to transmit through is the specimen, and other possible transmission paths would be suppressed. As such, it will be useful to determine the TL of the building elements/materials so that one can estimate the airborne sound insulation performance inside the building space.
As for impact sound which typically radiates from a floor into rooms below or horizontally, insulation can be done via floor coverings or floor slabs. This is because the applications of these items can reduce the impact sound pressure levels that travels into the receiver room. The typical methods of insulation are adding soft floor coverings on concrete slab, increasing the thickness of concrete floors, or implementing floating floors.
Single number ratings
To know the acoustic information of an insulation element, the standard method would be to refer to the single number ratings of that element. These ratings would be assigned to building materials based on their sound transmission spectra by the means of reference curves or weighted summation procedures.
The most used single-number rating for airborne sound insulation is the Sound Transmission Class (STC), which is in accordance with the American Society for Testing and Materials (ASTM) E413. There is another equivalent number called the Weighted Sound Reduction Index (Rw), which is based on the International Organization for Standardization (ISO) standard ISO 717.
The figure above shows an example of STC contour fitted to a concrete slab’s data. The differences between data points below the contour line and the value of contour are called the “deficiencies”. According to ASTM E413, the sum of deficiency should not be greater than 32 dB, and each individual deficiency should not exceed 8 dB (also known as the 8-dB rule). The reference contour for ASTM covers the frequency range from 125 Hz to 4000 Hz. The Rw contour from the ISO 717 has the same shape, except that it covers a broader frequency range of 100 Hz to 3150 Hz. Also, there is no 8-dB rule in ISO 717. Comparing both standards, the numbers from both ratings are usually close. However, the weighted summation method developed in ISO 717 accounts for the higher importance of low frequencies in traffic noise and modern music systems. As such, this method allows corrections/spectrum adaptation terms to be produced that can be used in conjunction with the Rw rating.
As for impact sound insulation, the sound pressure levels are often collected using a standard tapping machine and normalised, which will then be used with a reference curve to calculate its rating, typically the Impact Insulation Class (IIC), or the weighted index Ln,w. In fact, these ratings are commonly used in building codes. Again, the rating curves are identical in each standard, but there are some differences among them still. For instance, the ASTM IIC method does not allow any unfavourable deviation to exceed 8 dB. An increasing IIC rating would indicate that the impact sound insulation improves. Conversely, the Ln,w rating would decrease as the impact sound insulation gets better. We can take the relationship between both ratings as follow (assuming that the 8-dB rule is not invoked):
However, there is debate regarding the usefulness of ISO tapping machine data obtained on different types of floors. Therefore, the latest version of ISO 717-2 proposed the use of C1, a spectrum adaptation term to consider low-frequency noise that is normally generated below a lightweight joist floor. is the unweighted sum of energy in the one-third octave bands (50 or 100 Hz – 2500 Hz) minus 15 dB. According to the standard, this rating is expected to have a better correlation with the subjective evaluation of noise coming below floors, especially for low frequency ones.
The single rating numbers mentioned above are all useful when it comes to determining the level of acoustic insulation a material can provide. With the explanation above about room acoustics and the insulation measures that can be implemented, it will give a better idea on how one should tackle and handle the room acoustics in a building.
References
Crocker, M. J. (2007). Chapter 103: Room Acoustics. In C. H. Hansen, & M. J. Crocker (Ed.), Handbook of Noise and Vibration Control (pp. 1240-1246). Adelaide, South Australia, Australia: John Wiley & Sons, Inc. doi:ISBN 978-0-471-39599-7
Crocker, M. J. (2007). Chapter 105: Sound Insulation—Airborne and Impact. In A. C. Warnock, & M. J. Crocker (Ed.), Handbook of Noise and Vibration Control (pp. 1257-1266). Ottawa, Ontario, Canada: John Wiley & Sons, Inc. doi:ISBN 978-0-471-39599-7
Small studios are now widely used in the recording industry due to their high feasibility and them being economically friendly, which allows those working in the recording/music industry to be able to work remotely without needing to travel to big studios that much. With a good implementation of acoustic treatments, music recorded in small studios can still be high in sound quality, sometimes even suitable for commercial release.
So, what makes a recording studio good?
In today’s article, we will look into the acoustics of small recording studios, where music is performed as recorded (Everest & Pohlmann, 2015).
Ambient conditions
A quiet environment is a must for a studio to be useful, which is sometimes quite hard to achieve. First, noisy sites should definitely be avoided as many noise and vibration problems will not arise by just choosing a site in a quiet location for your studio. Avoid places near loud areas like train tracks, busy road intersections, or even an airport. The ultimate idea is to reduce the external noise spectrum, then keep the background noise within the criteria goal by implementing sound insulations in the building. However, the construction costs of effective insulation elements like floating floors or special acoustically treated walls/windows/doors may cost greatly. Hence, the best way, that is more cost-effective, will be to choose a quiet site in the first place, rather than isolating a studio located at a noisy place.
The HVAC system, which includes heating, ventilating and air-conditioning systems should be designed such that the acoustics meet the required noise criteria goals. The noise and vibration coming from motors, fans ducts diffusers etc. should be brought to the minimum so that low ambient noise levels can be achieved.
Noise
Similar to any other quiet rooms, a small studio needs to comply with the acoustical isolation rules and standards. It is important to construct the building elements with high transmission loss and decoupled from external noise and vibration sources to ensure that the ambient noise levels are low enough for good recording quality. Not only that, but these constructions will also act as an isolation that prevents loud noise (music) levels in the studio from affecting the neighbouring spaces.
Studio acoustical characteristics
Inside a studio, the types of sound present, and may be picked up by microphones, are the direct and indirect sounds. Direct sound is basically the sound coming from the source (before it hits a surface). Indirect sound follows right after the direct, caused by various non-free field effects characteristic of an enclosed area. In short, everything that is not direct sound is considered as indirect or reflected sound.
It is known that the sound pressure level in an enclosed space will vary according to the distance from a source, while also being affected by the absorbency of the room or space. If all the surfaces in a room are fully reflective, it means that the room is fully reverberant (like a reverberation chamber), therefore the sound pressure level would be the same (as of the sound from the source) everywhere in the room as no sound energy is absorbed. It can also be assumed that there is relatively no direct sound since most of the sounds are reflected, hence indirect. Another component that causes indirect sound comes from the resonances in a room, which is also the result of reflected sound.
Indirect sound also depends on the materials used for room construction (e.g., doors, walls, windows, floors, ceiling etc). These elements can also experience the excitation by the vibration of sound from the source, hence able to decay at their own rate when the excitation is removed.
Reverberation Time
The composite effect of all the indirect sound types is reverberation. Many would say that reverberation time is an indicator of a room’s acoustical quality, but in reality, measuring reverberation time does not directly reveal the nature of the reverberation individual components, giving a small weakness of reverberation time being the indicator. Therefore, reverberation time is often not the only indicator of acoustical conditions.
Reverberation time is, by definition, the measure of decay rate, and is usually known as T60. For example, a T60 of 1 second represents that a decay of 60 dB takes 1 second to finish. Some may say that it is inaccurate to apply the reverberation time concept to small rooms, as a genuine reverberant field may not exist in small spaces. However, it is still practical to utilize the Sabine equation (for reverberation) in small-room design to make estimations on the absorption requirements at different frequencies, provided that limitations of the process are taken into account during the estimation.
It is not good to have it being too long or too short. This is because for a room with reverberation time that is too long, speech syllables and music phrases will be masked hence causing a worsening speech intelligibility and music quality. Conversely, if the reverberation time is too short, speech and music will lose character therefore suffer in quality, whereby music will typically suffer even more. Despite that, there is no specific optimal value for reverberation time that can be applied for any rooms, because too many factors are also involved besides reverberation. Things like the types of sound sources (female/male voice, speed of speech, types of language etc) will all affect the room’s acoustic outcome. However, for practical reasons, there are approximations available for acousticians to refer to, where certain amount of compromise has been implemented to make it usable in many types of recording applications.
Diffusion A high diffusion room give a feeling of spaciousness due to the spatial multiplicity of room reflections, and it is also a good solution to control resonances effects. To create a significant diffusing effect, the implementation of splaying walls and geometrical protuberances works well. Another way will be to distribute absorbing materials in the room, which also increases the absorbing efficiency of the room apart from diffusion. Typically, modular diffraction grating diffusing elements (e.g. 2- x 4-ft units) can provide diffusion and broadband absorption, and can be easily installed in small studios. Still, there will not be much diffusion in a studio room, in practice.
Examples of acoustic treatment So, what are the acoustic treatment elements that you can use to improve your studio? These items below can be considered (Studio, 2021): 1. Bass Traps This is one of the most important tools to have in a studio. Bass traps are normally used to absorb low frequencies, also known as bass frequencies, but in fact they are actually broadband absorbers. This means that they are also good at absorbing mid to high frequencies too.
2. Acoustic Panels Acoustic panels work similarly like bass traps, but rather ineffective at absorbing the bass frequencies. One thing good about acoustic panels as compared to bass traps is that since they are much thinner, they offer more surface area with less material. Therefore, acoustic panels are capable of providing larger wall coverage with less cost as compared to bass traps.
3. Diffusers Diffusers may not be as effective as compared to bass traps and acoustic panels if used in small studios. So, this really depends on users, whether they find diffusers useful for their application. Now, where should the acoustic treatment products be placed at? There are three key areas of the room to be defined in this case: – Trihedral corners – Dihedral corners – Walls The priority for coverage goes from trihedral corners, dihedral corners to the walls. This is because acoustic treatments should ideally be placed at areas which have the greatest impact. At trihedral corners, for example, three sets of parallel walls converge, hence if there is absorption material located here, it catches the room modes from all three dimensions, giving three times the initial effectiveness. Same concept goes for dihedral corners and walls, but with two dimensions and one dimension respectively.
References Everest, F. A., & Pohlmann, K. C. (2015). Acoustics of Small Recording Studios. In F. A. Everest, & K. C. Pohlmann, Master Handbook of Acoustics (6th Edition ed.). McGraw-Hill Education – Access Engineering. doi:ISBN: 9780071841047 Studio, E.-H. R. (2021). CHAPTER 3: The Ultimate Guide to Acoustic Treatment for Home Studios. Retrieved from E-Home Recording Studio: https://ehomerecordingstudio.com/acoustic-treatment-101/
Noise barriers are designed to resist the sound waves in the propagation path from source to receiver. In general, the closer the barrier is to the source the more effective it becomes. For simple plane barriers the height and length are the most important factors determining the degree of screening achieved and simple design rules have been developed to determine the reduction in overall noise levels. These are based on the path difference between the direct path from source to receiver through the barrier and the shortest path passing over the top of the barrier. The greater this path difference the greater the screening. The shadow zone of the barrier is the region where the receiver cannot see the source and here the greatest reductions in noise levels are recorded. Some sound will always be diffracted over the top and around the edges of the barrier into the shadow zone so it is not possible to eliminate all noise from the source. However, typical barriers of a few metres high can achieve a worthwhile noise reduction of the order of 10 dB(A). This corresponds to halving the subjective loudness of the sound.
Figure (a)
Figure (b)
For more complex barriers simple methods are not appropriate and numerical methods such as the Boundary Element Method (BEM) have been used to produce accurate solutions.
Many different types of barrier have been installed using a wide variety of materials including wood, steel, aluminium, concrete and acrylic sheeting. Some of these designs have absorptive facings on the traffic side which reduce reflected sound. Barriers over 8 m in height have been used for some applications and novel capped barriers and angled barriers have been tested.
Barriers that may offer improved performance over simple plane barriers can be grouped under the following broad headings.
The above fig (a) shows the Main pathway of the sound propagation from the source to the barrier’s edge for sound walls with or without source-side absorption. Fig (b) shows Absorption material construction.
If smaller vehicles passing by the barrier, the reflection off the vehicle it does not play much of a role. Multiple reflections can only occur if noise barriers are built along both sides of the highway or train tracks.
In the case of large noise emitters, the implementation of source-side absorbent noise barriers can prevent the so-called zigzag effect
Absorptive barriers—that is, barriers incorporating elements on the traffic face that absorb a significant proportion of incident sound and hence reduce reflected sound which could contribute to overall noise levels in the vicinity.
Angled barriers—that is, barriers that are tilted away or have contoured surfaces angled to disperse the noise, the aim being to prevent significant sound reflections into the area where screening is required.
ABSORPTIVE BARRIERS
Where a plane vertical barrier is erected on one side of the road then sound reflections to the opposite side take place as illustrated in fig 1(a). In addition, reflections between vehicles and the barrier may lead to loss of screening performance as shown in fig (b). Where plane vertical barriers exist on both sides of the road, as shown in fig(c), they are normally parallel to each other and, in this situation, sound is reflected back and forth between the barriers again leading to a loss in performance. Absorbing panels located on the sides of the barriers facing the traffic can reduce this reflected contribution by absorbing the sound energy from the incident wave.
ANGLED BARRIERS
An alternative to using sound absorptive barriers is to angle the barrier or parts of the barrier away from the road such that the reflected wave from the traffic face of the barrier is deflected upwards, so reducing the contribution to noise at receptor positions relatively close to the ground. The performance of such barriers has been measured at full scale at TRL’s unique Noise Barrier Test Facility (NBTF). The noise source used consisted of an 800 W speaker that can be positioned in front of the test barrier on a specially laid strip of hot rolled asphalt, thereby representing the traffic source on motorways and all-purpose dual carriageway roads. Microphones can be positioned to measure the noise level in the shadow zone of the test barrier at any point on a wide flat grassland area free of reflecting objects. To measure the acoustic performance of the barrier, recorded noise in a broad frequency range is broadcast and noise levels are measured at standard locations behind the barrier. Corrections can be made for variations in speaker output and wind speed and direction. In this way the screening performance of the barriers for a typical traffic noise source can be evaluated.
A video she had filmed of the construction site shows the drone of the machinery could be heard reverberating along with the backup beeper of a truck at the site. This can go on up to 3 am as reported by the netizen.
Singapore — A member of the public has taken to Facebook after she realized that construction works were being carried out near her apartment even at night, causing a lot of noise in the area.
She put up a post on the Facebook group “Complaint Singapore” to seek advice from other netizens who might have encountered a similar situation before.
In her post, a member of the public also included a video she had filmed of the construction site. In the video, the drone of the machinery could be heard reverberating along with the backup beeper of a truck at the site.
According to the caption of the post, this was not the first time that such an incident had occurred. The member of the public also mentions that the construction works had gone on until 3 AM on a previous occasion. As such, she asked other netizens for help on who to contact on the issue, since the sounds generated by the construction works can be quite loud and disruptive.
Other netizens shared their views on the matter and offered suggestions in the comments section.
A few netizens chalked the nighttime construction down to urgency, saying that there might be an emergency that needs fixing quickly and promptly.
Some other netizens thought that carrying out construction work at night, would impede the flow of traffic less since there are fewer commuters during the night.
A few other netizens suggested that the poster bring the issue up to the relevant authorities such as the National Environment Agency (NEA), the Land Transport Authority (LTA), or the Singapore Police Force (SPF).
After contacting NEA, the poster replied that they were helpful in stopping the works at an earlier hour.
According to NEA, construction sites need to observe the noise level and exercise construction noise control with effect from 1 Oct 2007.
The way most workers need to complete tasks have significantly changed the way companies use their spaces. Quiet spaces are needed for deep, focused work. Technology enabled meeting rooms and collaboration spaces are used for productive meetings. Ideally, an office is designed in such a way that it enables team members to do their best work.
Unfortunately, it can be difficult to make sure a design includes all these aspects. As a result, designers and architects still often have to leave space for cubicles and open office spaces, a big contributing factor to general noise levels.
Did you know? Planting trees in your home or office not only helps to cool the internal temperature, increase the oxygen in the air give a feeling of freshness, and help relax only. But plants can also HELP ABSORB NOISE!
One creative way to both combat office noise and bring biophilic elements to a design is to incorporate plants and greenery into a space. Studies have shown that both plants and living green walls are an effective way to absorb sound and noise pollution.
Beyond their sound absorbing qualities, plants and biophilic elements can help to improve a worker’s overall well-being. Access to natural elements like greenery, natural light, and organic textures have been found to both improve employee productivity and reduce absenteeism. Plants have been found to be a mood booster and a stress reliever for team members, which can in turn, help to improve an employer’s bottom line.
Do Plants Help to Absorb Sound?
There is quite a bit of research on the subject, but the short answer is yes. The flexible and porous nature of indoor house plants acts as natural sound reducers. There are three ways that house plants can reduce the sound in your home or office: deflection, absorption, and refraction.
Most people do not understand the sound absorption benefits of houseplants. However, they really do help with absorption sound.
How Plants Reduce Indoor Noise Levels?
As mentioned above, plants reduce noise levels through three different methods: deflection, absorption, and refraction.
Deflection – Sound waves tend to bounce around off hard surfaces. That is where all that added noise comes from. Walls are rigid and will amplify sound, while plants are flexible and help to deaden the sound by breaking up the sound waves into other forms of energy.
Absorption – Plants are great at absorbing sound because of the leaves, branches, and wood. Wood is a great sound absorber. Have you ever walked through a forest and been amazed at the silence? That is because the trees are absorption all the ambient noise.
Refraction – Refraction is taking away the echoes of the sound bouncing off the hard surfaces. Plants will help to refract this noise and eliminate the echoes which are responsible for much of the added noise in your home or office.
The indoor plants that work best at absorbing sound such as:
Ferns: have a lot of surface space to help reduce sound. Their wide leaves spread out and cover quite a bit of area.
Baby’s Tears: Baby’s Tears are a dense plant that looks almost like moss. The plant has a way of draping itself over the pot and makes a great sound reducer when elevated off the ground.
The Peace Lily: The Peace Lily can absorb some of the sounds with their leaves and do a great job of bouncing the sound to the other plants and is a great sound absorbing plant you can put in your home. Their true noise absorbing properties are in their thick, broad leaves.
The Rubber Plant: The beauty of this plant is just how big it can get. Rubber plants cover a large surface area which only serves to enhance their sound absorbing properties.
Fiddle Leaf Fig: The fiddle leaf fig is another plant with broad, thick leaves. They can grow tall, and the cupped shape to the leaves make for an effective sound absorber.
What should an architectural acoustic consulting firm do? This question is very commonly asked when an acoustician is asked to submit a work proposal for a project. In this article, we will describe the scope of work of an acoustic consultant with reference to the type of mixed-use high-end building project. Because in this type of project an architectural acoustic consultant is required to be able to describe all the scope of work in one project with high complexity.
Details of the scope of work of acoustic consultants in mixed-use high-end building projects are as follows:
1. Criteria Formulation At the beginning of the project, the acoustic consultant must recommend design criteria/targets for various rooms and areas within the building such as retail, apartment units both for bedrooms and living rooms, and commercial areas such as meeting rooms, multifunction rooms, spas, fitness, restaurants. , club lounges, etc. These criteria are determined based on studies and summaries of the applicable standards in the country, international standards, client recommendations, and the building operator concerned.
2. Schematic With so many rooms that fall into the scope of work of an acoustic consultant with this type of project, it is highly recommended that an acoustician provide schematic designs for several important rooms for the attention of other consultants in the early stages of the project. Examples are MEP rooms, building structure connections, placement of HVAC equipment above the ceiling, and draft wall partition configurations.
3. Noise Review from the Environment Around the Building The acoustic consultant must review potential sources of noise from aircraft, train stations, transportation on highways, outdoor MEP equipment, and all things around the building that have the potential to interfere with audial comfort to the interior of the building to ensure the targeted acoustic criteria are achieved. At this stage the acoustician must be able to convey the results of modeling and simulations for several points around the building in the form of drawings that can be understood by clients and other consultants. At this stage, a building fa konfigurasiade configuration can be recommended that takes into account the noise from the area around the building.
4. Noise HVAC (duct-borne) Discussion and review of noise from all HVAC be it from air handling unit (AHU), axial and centrifugal fans, fan coil unit (FCU), etc. The ducting system will be analyzed to determine the noise level in the critical room from the nearest diffuser ducting system outlet. From this analysis, the need for silencers, lagging or duct linings will be recommended in order to achieve the acoustic criteria that have been determined. The analysis will be carried out on all HVAC systems without exception, with the greatest attention being on residential areas, spas, hotels, etc.
5. Sound Propagation in Building Structures (Structure-Borne) All matters relating to the propagation or vibration of sound via the building structure, whether it is due to human footsteps on the top floor or vibrations from the installation of MEP machines above the ceiling or floor. The acoustic consultant must be able to evaluate according to the natural frequency of the building structure and provide recommendations on floor slab elements to meet operator and client standards applied.
6. Machine Vibration Control The acoustic consultant should conduct an in-depth discussion on the vibration isolator for the installed machines. This is done by taking into account the deflection of the floor slab and its relationship to the static and dynamic loads of the machine (eg chiller, pump, cooling tower, AHU, etc.). In addition, ensuring the insulator is efficient to withstand vibrations to the building structure.
7. Room Insulation Discussion on the isolation of certain rooms by providing technical calculations both with the “indoor room” and “floating floor” methods so that sound and vibration do not propagate to all elements of the building, especially the room around the isolated area.
8. Acoustic Interior Reviewing and calculating room acoustic parameters on interior design elements of commercial spaces such as ballrooms, meeting rooms, and other areas where the clarity of speech or music is crucial.
9. Detailed Drawing The acoustic consultant must provide or recommend specifications for building skin elements such as faades, walls and floor slabs in CAD format on a cut or plan basis. This will make it easier for relevant consultants to apply these specifications in their construction drawings.
10. Noise Isolation Due to Impact Collisions in the fitness area, whether it’s due to aerobic activity or lifting weights, are a special concern for acoustic consultants. In addition to different forms of acoustic treatment, the time span of these activities must also be included in detailed technical calculations, and of course measurable.
11. Review of Related Consultant Drawings After all acoustic treatments have been adapted to construction drawings by the relevant consultant, the acoustician must review all these drawings to ensure that all treatments have been described correctly, before entering the tender phase.
12. Coordination with Selected Contractors The acoustic consultant must allocate time to coordinate the design and answer questions from the selected contractor and sign all forms related to material approval if it is in accordance with the acoustic intentions.
13. Final assessment Before handing over the project to the next party, the acoustic consultant must conduct a final assessment of the building elements designed by the consultant. Next, compare the measured value to the design target and pre-determined criteria.
