Allowable Noise Levels Research Articles

Assessment of Noise Levels of Churches in the Kpone Katamanso Municipal Assembly in Ghana.

Different sound levels are encountered by pastors, ministers, and the whole congregation during church services, which may extend for hours, and also by people living close to these churches. This can have an adverse effect on their health. The maximum allowable noise level in worship places is 65 dB (A), according to the Ghana Standards Authority (GSA). The aim of the study was to quantify the noise pollution levels of the churches in Kpone Katamanso Municipal Assembly (KKMA) and assess the equivalent noise levels of the churches' indoor and outdoor spaces. This investigation is being conducted due to the high number of churches and the noise emanating from these churches in the Kpone Katamanso Municipality and the possible impact on human health. Thirty churches were chosen at random for the study; on Sundays between the hours of 7.30 and 12.0 pm, sound levels in churches were measured using a portable General Class 1 Meter type DSM403SD with a data logging system. MS Excel was used to evaluate the data and determine characteristics including noise exposure levels (NEL), background noise level (L 90), severe noise level (L 10), and equivalent noise level (L eq). The indoor equivalent noise level ranges from 74.5 dB (A) to 104.1 dB (A), and the outdoor equivalent noise level ranges from 52.6 dB (A) to 85.3 dB (A). All of the noise levels found indoors of the churches were greater than the 65 dB (A) safe allowable limit, putting the congregants and residents at risk for a variety of physiological and psychological problems.

Assessment of noise pollution in Rajshahi city and remediation

This research article reports on a study conducted on 2022 and 2023 to measure noise levels at five selected locations in Rajshahi, Bangladesh. During the study, selected noise locations NQ1 and NQ4 fell under the silent zone, NQ2 and NQ5 fell under the commercial zone, and NQ3 fell under the industrial zone followed by the regulations of Bangladesh. The maximum allowable noise level of Bangladesh at day time are 50 dB(A) in the silent zone, 70 dB(A) in the commercial zone, and 75 dB(A) in the industrial zone. The study found that noise levels at NQ1 and NQ4 exceeded the Bangladesh standard by almost 75%, while noise levels at NQ2 and NQ5 were around 25% higher than the standard. The study also measured the noise levels of auto-rickshaws using TT Horn and Plastic Air Horn and found that the noise level for the Plastic Air Horn was within the limit, but it was exceeded for the TT Horn. The study highlights the need for regulations to control noise pollution in Bangladesh and suggests possible interventions to reduce noise levels from auto-rickshaws.

Effect of Vehicular Stream Characteristics on Traffic Noise

Human health can be negatively impacted by exposure to loud noise, which can harm the auditory system. Traffic noise is the leading cause of noise pollution. This paper studies the problem of noise pollution on the roads in Baghdad, Iraq. Due to the increase in vehicle numbers and road network modifications in Baghdad, noise levels became a serious topic to be studied. The aim of the paper was thus to study traffic noise levels and the effect of the traffic stream on noise levels and to formulate a prediction model that identified the guidelines used for designing or developing future roads in the city. Then, the noise levels were measured based on five variables: the functional classification of roads, traffic flow, vehicle speed, distance from the carriageway, and skid number. An analysis of traffic noise prediction was conducted using a simple linear regression model to accurately predict the equivalent sound levels. Finally, the findings have shown that the formulated prediction model gives acceptable prediction noise levels since the R2 is 88.83%. The results showed that the noise levels measured were 23.1% and 48.8% higher than the allowable noise levels limited by Iraqi standards during the daytime and nighttime, respectively. Further, studying the alternatives used to improve the performance of the environment on the existing roads in Baghdad can be considered as a future research direction. Doi: 10.28991/CEJ-2022-08-12-016 Full Text: PDF

Minimum Friction Losses in Planetary Stages of Wind Turbine Gearboxes

Mechanical efficiency is not a critical design factor of wind turbine gearboxes since wind energy is abundant and costless. The design and sizing of the gears will be determined by the requirements of power density, gear ratio, fatigue safety, and allowable noise and vibration levels. However, reducing power losses results in lower lubricant heating, and therefore, a smaller cooling system is required with lower induced thermal stresses. Reducing friction losses will therefore be beneficial for the mechanical behavior of the gearbox. This paper provides a new method for the calculation of the optimal values of the outside radii and rack shift coefficients of planetary gear stages to minimize the friction power losses, maintaining unalterable geometrical and operating parameters that ensure the preestablished values of the aforementioned critical design factors.

Monitoring noise level in cities: A step towards urban environmental quality management in Nigeria

Noise as an undesirable sound within non-occupational settings is one of the several identified environmental problems across the world. It is an increasing common feature of urban areas attributable to road, rail, and air traffic sources as well as construction and industrial activities, commercial enterprise, and such familiar domestic sources as pets and radios/stereos from residential neighborhood. Noise is a major pollution which constitutes nuisances and health related consequences of significant negative impacts on the physical, social, physiological and psychological wellbeing of man or animals. It is notably evident that increased activities from industrialization and technological transfers/drifts are the bedrock of urban noise in majority of our rapid growing cities at present. At the instance of sufficient evidence that noise aggravates chronic illnesses like hypertension and other cardiopulmonary diseases, the World Health Organization (WHO) and the Federal Environment Protection Agency (FEPA) (Nigeria) has strategically set standards and limits of allowable noise levels which unfortunately is not implemented and enforced in most cities, thereby leading to urban quality deterioration. Noise pollution occurs when it is observed that standards are exceeded, therefore concerted efforts in monitoring and regulating our environmental noise is recommended to avert the scourge of further debasement of environmental quality in our cities.

Pengendalian Kebisingan Dari Aktivitas Penerbangan di Lingkungan Sekitar Bandara Sultan Thaha Jambi dengan Pemanfaatan Ruang Terbuka Hijau

Noise is a sound pollution and its existence is undesirable in a certain level and time, which has the potential to cause human health problems and environmental comfort. One of the causes of noise levels is due to airport operational activities, from landing to take off. For this reason, it is necessary to control the noise around the Sultan Thaha Jambi airport area, by utilizing green open space as a barrier that can reduce noise levels. This study aims to determine the level of airport noise in certain zones and evaluate the existence of green open space (RTH) whether it is appropriate to become a natural barrier as a barrier to reduce noise caused by flight activities from Sultan Thaha Jambi airport. The results showed the noise level dB (A) from flight activities in each zone, namely the lowest in zones 1 and 3, amounting to 52.08 dB (A), and the highest in zone 5 at 87.93 dB (A). , while the existence of Green Open Space (RTH) is only in zone 1, and 3 are forest park areas, and fields around the Sultan Thaha Jambi airport area, so the existence of this Green Open Space (RTH) is able to reduce noise levels by 2.11 dB (A) based on KEP-48 / MNLH / 11/1996 the quality standard of the allowable noise level is 50 dB (A). While zone 5 is a residential area, the noise level figure is quite high, namely 87.93 dB (A), due to the densely populated area, lack of green open space (RTH), and proximity to motorized vehicle transportation activities, and adjacent to the runway. runway airport. However, not all activities are carried out continuously. So that the residential area is still feasible if exposed to noise exposure either from airport activities or other activities.

Impact of measuring microphone location on the result of environmental noise assessment

The basic objective of environmental protection against noise is the care for acoustic climate, among others via maintaining the allowable noise levels. In many countries, ISO 1996 standards constitute the reference for the measurement and assessment of acoustic environment, thus it is necessary to verify the guidelines contained therein in different measurement circumstances. The presented study covered the recommended −3 dB correction for microphone location at a distance of 0.5–2.0 m from building façade. Two different noise types are analyzed: road (extended source) and industrial (point source). With the use of A-weighted equivalent sound level indicator it has been determined that the actual reflection of sound from building façade are considerably lower than 1 dB. The applications proposed a modification on the guidelines for microphone location near building façade with regards to the ISO 1996-2:2017 standard. The modification applies only to measurements performed to control compliance with noise limits in the environment.

Sound environment quality in nursing units in Chinese nursing homes: A pilot study

Recent studies have investigated sound environment in nursing homes. However, there has been little research on the sound environment of nursing units. This research sought to address this gap. Subjective evaluations were gathered using questionnaire surveys of 75 elderly residents and 30 nursing staff members in five nursing units of five nursing homes in Chongqing, China. Background noise level and reverberation time were measured in five empty bedrooms, five occupied bedrooms and five occupied nursing station areas, in five nursing units. The subjective evaluation results indicate that the residents stay in the nursing units for most of their waking hours. The residents and nursing staff had strong preferences for natural sounds, with the lowest perceptions of these in the nursing units. The background noise level in all the occupied bedrooms exceeded Chinese standards for waking and sleeping hours. Only 20% of the occupied nursing station areas were below the allowable noise level for recreation and fitness room during sleeping hours. The nursing station area was identified as the main source of noise in the unit during waking hours. The average background noise level of the occupied bedrooms was 3–12 dBA higher than that of the empty bedrooms during sleeping hours. Attention should be given to the implementation of noise specifications for sleeping hours. The reverberation time of the bedrooms was within the range of 0.44–0.68 s, and in the nursing station areas it was 0.63–1.54 s.

Extensive underwater radiated noise analysis of a research vessel in compliance with DNV SILENT notation

Studies have shown that underwater-radiated noise from ships may have both short and long-term negative consequences on marine life, especially marine mammals. An international community of researchers, environmental groups, government agencies, and sectors of the shipping industry has recognized shipping noise as an important marine conservation issue. In 2010, Det Norske Veritas (DNV, the Norwegian Classification Society) made the first attempt to fix the radiated noise limits for commercial ships, in which vessels fulfilling the requirements will be given an optional class notation SILENT. In this study, underwater noise measurements were performed on a new research vessel in shallow water in compliance with DNV SILENT notation. More speeds were tested than required by DNV, to understand the characteristics of related noises. Results show the new ship satisfies the allowable noise level curve for type R (Research); however, the measured noise levels do not increase as speed accordingly. Moreover, level differences can be significant between starboard and port side tracks especially at low frequencies. Commonly observed coastal currents play an import role on ship maneuverings and test conditions and therefore unexpected results. Practical considerations and suggestions about performing measurements and analyzing the data will be discussed and summarized.Studies have shown that underwater-radiated noise from ships may have both short and long-term negative consequences on marine life, especially marine mammals. An international community of researchers, environmental groups, government agencies, and sectors of the shipping industry has recognized shipping noise as an important marine conservation issue. In 2010, Det Norske Veritas (DNV, the Norwegian Classification Society) made the first attempt to fix the radiated noise limits for commercial ships, in which vessels fulfilling the requirements will be given an optional class notation SILENT. In this study, underwater noise measurements were performed on a new research vessel in shallow water in compliance with DNV SILENT notation. More speeds were tested than required by DNV, to understand the characteristics of related noises. Results show the new ship satisfies the allowable noise level curve for type R (Research); however, the measured noise levels do not increase as speed accordingly. Moreover, level...

Children who say hand dryers 'hurt my ears' are correct: A real-world study examining the loudness of automated hand dryers in public places.

Previous research has suggested that hand dryers may operate at dangerously loud levels for adults. No research has explored whether they operate at a safe level for children's hearing. Children's ears are more sensitive to damage from loud sounds than adult ears. Health Canada prohibits the sale of toys with peak loudness greater than 100 dB. This study tested installed dryers in public washrooms to see if they were safe for children's hearing. Forty-four hand dryers in public washrooms were each measured for peak sound levels in a standardized fashion, including at children's ear canal heights. Each dryer was measured at 10 different combinations of heights and distances from the wall, and with and without hands in the air stream coming from the hand dryer, for a total of 20 measurements per dryer. Xlerator units performed the loudest, with all being louder than 100 dBA at all measurements whenever hands were in the airstream. Several Dyson Airblade models were also very loud, including the single loudest measurement of 121 dBA. While some other units operated at low sound levels, many units were louder at children's ear heights than at adult ear heights. Many dryers operated much louder than their manufacturers claimed, usually greater than 100 dBA (the maximum allowable noise level for products/toys meant for children). This study suggests that many hand dryers operate at levels far louder than their manufacturers claim and at levels that are clearly dangerous to children's hearing.

Noise induced hearing loss (NIHL) in wasit corporation textile industries

Background: Noise Induced Hearing Loss (NIHL) is used to symbolize accumulative and persistent hearing loss due to progressive exposure to high levels of noise for months or year. Design: A cross-sectional study. Setting: Al-Karama Teaching Hospital and Wasit Co. Textile Industries. Aims and objective: To specify frequency of hearing loss among workers in the knitting industry, to registration the level of the noise in the weaving department and to specify the realization about the impact of noise on the hearing. Materials and methods: From June to August 2011, the level of noise in the weaving department has been recorded. 200 workers had been sent to our hospital, interviewed according to already prepared questioner and audio logically assessed. Results and discussion: The mean level of noise at 12measurement points was 87-96dB. Which was greater than the allowable noise level for continuous 8 hours working per day? It has been established that 113 workers had NIHL, 29% of hearing loss (the greater percentage) was in the mild category (26-40dB) at high frequency (4-6KHz) group and the minimal NIHL notch within 2 kHz and 4KHz were 6% and 22% from the workers respectively. The hearing difficulty was not the most common complaints 29.4%, while ear discomfort was 55.4% and tinnitus was 43%, because NIHL usually include the high frequencies at first hence the worker can promote the NIHL and he didn't complain from loss of hearing. No one used the personal noise protective devices (PPD) and only 44 workers (24%) (P-value≤ 0.1) who considers that the noise is a hazard on health. Conclusion: Wasit Co. Textile Industries Noise measurement is greater than the allowable noise scale for 8 hours. NIHL can be developed many years before worker will complain from hearing loss.

Evaluation of Noise in the Vicinity of a Hospital and a Gated Community

An evaluation was made of the acoustic environment of the Green Line North (GLN) by noise mapping calculations. In addition, the equivalent sound pressure levels, Leq, that reach the facades of a residential building and a hospital located along the GLN, were simulated to determine the noise levels to which they are subjected. The simulated noise levels were compared with the maximum allowable noise levels established by Curitiba Municipal Law and by the Brazilian standard on Noise Assessment in Populated Areas. It was concluded unequivocally that, in the current situation, noise pollution affects the hospital and the gated community. A simulation of heavy vehicle traffic reduction was performed, aiming at evaluating the impact of this mitigation measure. Even the reduction of number of heavy vehicle to 10% of the original number proved to be insufficient to attend values established by the municipal law and the Brazilian standard.

Noise dosimetry for tactical environments

Noise exposure and the subsequent hearing loss are well documented aspects of military life. Numerous studies have indicated high rates of noise-induced hearing injury (NIHI) in active-duty service men and women, and recent statistics from the U.S. Department of Veterans Affairs indicate a population of veterans with hearing loss that is growing at an increasing rate. In an effort to minimize hearing loss, the U.S. Department of Defense (DoD) updated its Hearing Conservation Program in 2010, and also has recently revised the DoD Design Criteria Standard Noise Limits (MIL-STD-1474E) which defines allowable noise levels in the design of all military acquisitions including weapons and vehicles. Even with such mandates, it remains a challenge to accurately quantify the noise exposure experienced by a Warfighter over the course of a mission or training exercise, or even in a standard work day. Noise dosimeters are intended for exactly this purpose, but variations in device placement (e.g., free-field, on-body, in/near-ear), hardware (e.g., microphone, analog-to-digital converter), measurement time (e.g., work day, 24-h), and dose metric calculations (e.g., time-weighted energy, peak levels, Auditory Risk Units), as well as noise types (e.g., continuous, intermittent, impulsive) can cause exposure measurements to be incomplete, inaccurate, or inappropriate for a given situation. This paper describes the design of a noise dosimeter capable of acquiring exposure data across tactical environments. Two generations of prototypes have been built at MIT Lincoln Laboratory with funding from the U.S. Army, Navy, and Marine Corps. Details related to hardware, signal processing, and testing efforts are provided, along with example tactical military noise data and lessons learned from early fieldings. Finally, we discuss the continued need to prioritize personalized dosimetry in order to improve models that predict or characterize the risk of auditory damage, to integrate dosimeters with hearing-protection devices, and to inform strategies and metrics for reducing NIHI.

Virtual Strain Gage Size Study

DIC is a non-linear low-pass spatial filtering operation; whether we consider the effect of the subset and shape function, the strain window used in the strain calculation, of other post-processing of the results, each decision will impact the spatial resolution, of the measurement. More fundamentally, the speckle size limits, the spatial resolution by dictating the smallest possible subset. After this decision the processing settings are controlled by the allowable noise level balanced by possible bias errors created by the data filtering. This article describes a process to determine optimum DIC software settings to determine if the peak displacements or strains are being found.

Evaluation of noise producing toys and the product standard criteria

BackgroundA selection of commercially available imported toys was assessed for acoustic safety by testing to the voluntary toy safety Standard. The results were compared to allowable noise levels for adults...

NÍVEL DE POTÊNCIA SONORA NAS OPERAÇÕES AGRÍCOLAS

SUMMARY: The noise generated by agricultural mechanization brought side effects, and one of them is the damage the hearing of the operator of agricultural machinery. The NR-15 establishes the limits of tolerance for continuous noise, and exposure to the maximum allowable noise level of 115 dB (A) for individuals who are not using individual protection equipment and 85 dB (A), considering a shift work of 8 h. The objective was to study the influence of working speed and soil condition in agricultural operations in the determination of sound power levels emitted by the tractor. The study was conducted at the Center for Agricultural Sciences - UNIVASF, Petrolina / PE using a Valtra tractor model 785 TDA cabin and meter without the sound power level. We evaluate the sound power level of the tractor in five speeds (3.0, 5.0, 8.7, 10.7 and 13.0 km h -1 ) on prepared soil and ground covered with weeds, with the equipment: lightweight tandem grid, grid light off-set with discs of 55.8 cm, grade mild off-set with discs of 60.8 cm, chisel plow, mower and distributor commuting. The most significant amounts were found in the tractor and plow in operation, noting that the requirement of increased power in the engine sound power level.

A logistic prediction model for individual allowable noise levels

Annoyance to noise is probably a good measure of the potential for complaint and community action. Each individual's degree of annoyance to noise cannot be accurately predicted from conventional laboratory studies and social surveys. Therefore, a logistic prediction model for individual allowable noise levels has been developed. In a previous paper [K. Furihata et al., Acta Acust. Acust. 93, 73-83 (2007)], an annoyance scale using the most frequently used annoyance ratings related to noise for community noise assessment in Japan was constructed. The dose-response relationships were obtained by actually listening to sounds in a field situation (1474 subjects) carried out at 14 metropolitan cities in Japan. The logistic prediction model was developed using the logistic regression parameters estimated from each cumulative percentage curve of seven annoyance scale scores based on all data (n=2940). To verify the hypothesis, individual relationships between annoyance and L(Aeq, (5 min)) for 24 normal-hearing subjects were constructed using a laboratory experiment. The main conclusion drawn from the results is that if at least one dose-response relation is obtained from each subject, the model can predict whether a sound is annoying or not from its L(Aeq,(5 min)) value. Moreover, validation of the model is needed in a field situation.

Modelling the disturbance caused by a dc-electrified railway to geomagnetic measurements

Abstract Magnetic fields created by a dc-electrified railway are a nuisance to the operation of a geomagnetic observatory and also disturb other electromagnetic studies. Theoretical formulas that enable quantitative estimates of the magnetic effect of a dc railway including leakage currents in the ground are presented in this paper. They are illustrated by numerical examples. The validity of the theoretical model was verified by measurements carried out in the vicinity of a nearly north-south railway in Calgary, Canada. The earth structure in that area is approximately layered, which is an assumption included in the theoretical model. The agreement between the measured magnetic fields due to trains and the theoretical values is good. Numerical computations indicate that magnetic fields larger than the maximum allowable noise level (assumed to be about 10 pT) at today’s magnetic observatories may extend to distances of tens of kilometres from a railway. We have prepared computer programs based on the theoretical formulas in the MatLab, Octave, FORTRAN and IDL languages, in which the locations (i.e. the latitudes and the longitudes) of the point of observation, of the feeding substations and of the trains, together with the feeding and leakage currents and the heights of the feeding lines, can be given as inputs.

Individual susceptibility to noise-induced hearing loss

The new EU directive (10/2003/EU) sets new limits for allowable noise levels and sets new requirements to accommodate the individual susceptibility factors, but does not define these factors. We aim to evaluate the effects of environmental and biological factors on the damage to hearing by noise. The history of work exposure, use of hearing protective devices (HPD), audiometric data and information on environmental and biological factors were collected from well over 1000 workers. The group consisted of 406 paper mill workers, 400 miners, 250 metal factory workers, 176 shipyard workers and 124 forestry workers. For comparison we evaluated 685 noise-exposed subjects visiting a hearing aid clinic for fitting of a hearing aid. They were exposed in their work to noise levels of 80–115dB(A). The environmental and biological factors encompassed smoking habits, the use of analgesics, serum cholesterol, systolic or diastolic blood pressure as well as noise exposure. There were a number of confounders which were s...

The challenges of lawnmower noise reduction

The European Noise Directive (2000/14/EC) became effective in the year 2000, limiting the allowable noise level for lawnmowers sold in the European Union. Noise level limits are based on cutting width. The Directive requires that manufacturers meet these limits and include statistical uncertainties, then declare their noise levels and have these results certified by an independent third party agency. There are two major challenges with this Directive. First by taking statistical uncertainties into account, this creates a limit lower than the published limit. Second is to lower the sound power level while still maintaining acceptable performance. The physical phenomena that generate the unwanted noise of a lawnmower are also used to perform work. For rotary lawnmowers, a dominant noise source is the cutting deck assembly, which is required to lift and cut grass, then dispose of the clippings. To cut grass with a good quality of cut appearance, the blades are required to turn at a very high tip speed to generate the necessary airflow. For lawnmowers, noise levels and unit performance are intrinsically linked. This has frustrated our industry for over 20 years.