Traffic noise attenuation solutions for naturally ventilated classrooms in South Africa

2021 ◽  
pp. 1351010X2110640
Author(s):  
Coralie van Reenen ◽  
Chrisna du Plessis
Keyword(s):  
South Africa ◽  
Speech Intelligibility ◽  
Numerical Study ◽  
Signal To Noise Ratio ◽  
Traffic Noise ◽  
Sound Level ◽  
School Design ◽  
Noise Attenuation ◽  
The Road ◽  
Typical Situation

Traffic noise transmission through the open windows of naturally-ventilated classrooms can reduce speech intelligibility and can negatively impact academic performance. The findings of a numerical study are presented. Software was used to assess effective noise attenuation solutions for naturally-ventilated classrooms exposed to traffic noise. A typical situation in urban schools in Gauteng, South Africa, is considered in which classrooms are ventilated by large open windows in accordance with national building regulations and norms and standards for school design. The aim of the study was to establish a heuristic framework for early design decisions regarding how far from the road a classroom building should be set, and the effective height and position of a solid noise barrier to ensure a suitable ambient noise level inside a classroom with open windows. Efficacy was measured with reference to an indoor ambient sound level of 40 dBA. The findings show that with the insertion of barriers, the required ambient level was achieved for a classroom at least 68 m from the road, if the barrier is at least 3.5 m high. However, it was found that a significant insertion loss (>6 dB) and an improved signal to noise ratio could be achieved for classrooms as close as 17 m from the road with a barrier of at least 2 m high. Though not broadly generalizable, the findings provide a heuristic guide applicable for designing new schools or selecting attenuation interventions in existing city schools that are similar to those used in the study.

scholarly journals Analysis of Traffic Noise in Taman Kota Lumintang Denpasar

2019 ◽  
Vol 10 (02) ◽  
pp. 20585-20591
Author(s):  
Adrian Pradana ◽  
I Made Tamba ◽  
I Ketut Widnyana
Keyword(s):  
Noise Level ◽  
Open Space ◽  
Direct Method ◽  
Traffic Noise ◽  
Ground Level ◽  
Quality Standard ◽  
Sound Level ◽  
The Road ◽  
Level Meter ◽  
City Park

This research was conducted to analyze the level of traffic noise in Lumintang City Park, Denpasar. The measurement method is by using a direct method that is using an integrating sound level meter that has an LTMS measurement facility, namely Leq with a measuring time every 5 seconds. The examination is carried out by measuring for 10 minutes. The measurement time is carried out during the 24 hour activity (NGO) on December 3, 2018. The measurement distance ranges from 5-10 meters from the road, with a height of 1-1.2 m from the ground level. The results of the research on the level of traffic noise in Lumintang City Park Denpasar showed the noise level that exceeded the noise level quality standards of the green open space area of 50 dB, where in the first lane the traffic noise level was 92.52 dB at L3. While the noise research in lane 2 shows that the highest traffic noise level of 85.70 dB occurs at L5. For day and night (NGO) noise levels in lane 1 amounting to 70.13 dB and lane 2 of 67.95 dB has exceeded the quality standard of green open space, so that it can cause physical and psychological disturbances for visitors to the Taman Lumintang City of Denpasar..

Acoustic Prediction Modeling and Sound Mapping of public transport users' exposure at a bus stop.

2021 ◽  
Vol 263 (2) ◽  
pp. 4058-4069
Author(s):  
Dayane Cristina Lima Estercio ◽  
Paulo Fernando Soares
Keyword(s):  
Road Traffic ◽  
Traffic Noise ◽  
Sound Level ◽  
Road Traffic Noise ◽  
High Frequencies ◽  
Reference Models ◽  
The Road ◽  
Bus Stop ◽  
Specular Reflections ◽  
The City

The objective of this research is to develop a mathematical model to predict the road traffic noise level at the bus stop, to assess the level of noise that users of these urban facilities are exposed daily. To help assess the exposure and the environmental impact, sound mapping will be performed using the IMMI software. In the model, the calculation of direct paths and specular reflections and diffuse was adopted. The study was applied in three sections in the city of Maringá, Brazil. At each point, the user was simulated standing and sitting. The sound source was positioned on the axis of each strip, every five meters. In total, 5124 readings of source positions were evaluated in 84 measured points. For the validation, the Anderson-Kurze, Kang, Yang and Zhang, Bistafa and Naish model were applied, and then the t-Student test were applied. The results showed a correspondence between the developed model, the data of the measurements and the reference models in the range of 25 Hz to 10000 Hz, there was a greater variance between the models applied in the high frequencies. It is concluded that the model was able to estimate the sound level of the stretches evaluated.

Effect of distance from road intersection on developed traffic noise levels

2004 ◽  
Vol 31 (4) ◽  
pp. 533-538 ◽  
Author(s):  
Saad Abo-Qudais ◽  
Arwa Alhiary
Keyword(s):  
Noise Level ◽  
Traffic Noise ◽  
Sound Level ◽  
Signalized Intersections ◽  
Environment Pollution ◽  
Noise Levels ◽  
The Road ◽  
Traffic Intersection ◽  
Noise Measurements ◽  
Level Meter

The main objective of this study was to evaluate the variation in traffic equivalent noise levels as distance from the road intersection increases. To achieve this objective, traffic volume and equivalent noise level were monitored at 40 signalized intersections in Amman, the capital of Jordan. An integrated sound level meter (ISLM) was used to measure 1 min equivalent noise level along all approaches of the evaluated intersections. A total of 3326 noise measurements were performed. The collected data were analyzed to evaluate the variation of noise levels as distance from the intersection increases. The results indicated that equivalent noise levels were significantly affected by distance from the signal stop line. The equivalent noise levels at distances 50 and 100 m from the intersection were found to be 1.5 to 2.0 dB less than those at 0 m. While at 200, 250, and 300 m from the intersection, the monitored equivalent noise levels were found to be 3.8 to 4 dB higher than that at 0 m. At distances farther than 250 m, the measured equivalent noise levels tend to keep constant value of equivalent noise level as distance increased.Key words: noise, traffic, intersection, environment, pollution.

scholarly journals Analysis of Traffic Noise in Two Cross-Sections at the Road Crossing The City

2020 ◽  
Vol 23 (1) ◽  
pp. B13-B21
Author(s):  
Andrzej Bąkowski ◽  
Leszek Radziszewski
Keyword(s):  
Cross Sections ◽  
Acoustic Pressure ◽  
Road Traffic ◽  
Traffic Noise ◽  
Sound Level ◽  
Road Traffic Noise ◽  
The Road ◽  
Recorded Data ◽  
Relative Differences ◽  
The City

The paper presents an analysis of the noise recorded by the two road traffic noise-monitoring stations. The stations were located in Kielce, Poland, at the road No. 74: on the outskirts of the city and near the center. Based on the experimentally recorded data, an equivalent sound level and acoustic pressure were determined for three sub-intervals of the day: nights, days and evenings. The conducted analyses showed that the average annual values (depending only on the time sub-intervals) of the median do not differ significantly between stations. A similar conclusion can be drawn based on simulations of the median and the C90 percentile of the sound pressure . However, the maximum relative differences in the C99 percentile of the acoustic pressure between stations are around 13%. The maximum relative differences in median pressure between stations are around 15% (for the time sub-interval nights).

An objective evaluation method and experiment on the impact of road traffic noise on the soundscape: The case of West Lake

2021 ◽  
Vol 263 (4) ◽  
pp. 2851-2862
Author(s):  
Jiping Zhang
Keyword(s):  
Speech Intelligibility ◽  
Evaluation Method ◽  
Road Traffic ◽  
Signal To Noise Ratio ◽  
Traffic Noise ◽  
Measurement Techniques ◽  
Objective Evaluation ◽  
Road Traffic Noise ◽  
West Lake ◽  
The Impact

A positively judged soundscape generally includes both natural and social/cultural sounds in the sonic environment. Road traffic noise (RTN) is a major source of sound that may impact the both, such as the case of West Lake. Many studies examine soundscapes contexts with RTN based on physical descriptors, and subjective social scientific assessments by their descriptors mainly using onsite questionnaires to develop an understanding of the situation. By application of an objective evaluation method borrowed from speech intelligibility measurement techniques defined as the signal-to-noise-ratio-loss in the presence of RTN, research of the correlation between background RTN and environmental soundscape is developed by a self contained and evident proof derivation, proposed an objective evaluation method for protecting the soundscape from RTN, and presented the design and performance of an experiment to verify the method at two roads where RTN is propagated a distance into two roadside urban parks at West Lake. Our goal is the assessment and protection of the environmental soundscape from RTN using a convenient objective evaluation method that supplements cumbersome subjective investigations, provides an early warning concerning the RTN impact to the soundscape, and a tool how to improve the soundscape within the RTN impacted areas.

Natural Speech Intelligibility in Theatres in Relation to Their Acoustics

2011 ◽  
Vol 18 (3-4) ◽  
pp. 293-311
Author(s):  
Maarten P.M. Luykx ◽  
Martijn L.S. Vercammen
Keyword(s):  
Background Noise ◽  
Speech Intelligibility ◽  
Signal To Noise Ratio ◽  
Speech Sound ◽  
Sound Level ◽  
Natural Speech ◽  
Noise Levels ◽  
Signal To Noise ◽  
Background Levels ◽  
Noise Ratio

There is a certain tendency in the design of theatres to make the halls quite large. From a perspective of natural speech intelligibility and strength of speech this is disadvantageous, because an actor's voice has a certain, limited loudness and consequently the signal-to-noise ratio at the listener may become too low. Based on the influence of signal/noise ratio on speech intelligibility, it is deduced that the strength G ≥ 6 dB and room volumes have to be limited to 4000–4500 m3 in order to maintain sufficient loudness for natural speech. Sound level measurements during performances with natural speech in a theatre have been performed, to determine background noise levels in the hall due to the audience and to investigate the signal-to-noise ratio of the actors voice at the audience. The background levels are mainly determined by installation noise and not by the influence of the audience.

scholarly journals POTENSI VEGETASI SEBAGAI PEREDAM INGAR BUNYI KENDARAAN BERMOTOR

2019 ◽  
Author(s):  
KEMALA
Keyword(s):  
Noise Control ◽  
Traffic Noise ◽  
Quality Standard ◽  
Control Area ◽  
Sound Level ◽  
Noise Attenuation ◽  
Sound Level Meter ◽  
Research Focus ◽  
Vegetation Measurement ◽  
Level Meter

The increases of transportation everyday have made multiple effects especially for human heal th. Based on the effects appeared by noise, there were three steps could be done to prevent, to reduce, or to control it. First, noise control at the source of noise, second, noise control at the line, and third, noise control for the receiver (human). This research focus on noise control at the source of noise by plants. The purpose of this research was to investigate the traffic noise attenuation by vegetation. The noise was measured with Sound Level Meter and was taken at two areas, control area without vegetation and deal area with vegetation. Measurement was done in busy days and weekday in the morning, midday, and afternoon. The measurement repeated as many as three. The observation showed that the traffic noise in control area ranging from 77.3 -79.4 dBA, whereas in deal area traffic noise ranging from 56.3-59.4 dBA. In this case, vegetation could reduce the traffic noise as many as 20-21 dBA although the observation result over quality standard which defined by The Ministry of Environment no. 48/1996, that was 65 dBA for office and commerce (control area), and 55 dBA for housing and settlement (deal area).

scholarly journals Modelling of road traffic noise

2018 ◽  
Vol 157 ◽  
pp. 02001
Author(s):  
Andrzej Bąkowski ◽  
Leszek Radziszewski ◽  
Vladimir Dekys
Keyword(s):  
Road Traffic ◽  
Traffic Noise ◽  
Sound Level ◽  
Road Traffic Noise ◽  
Urban Mobility ◽  
Level Indicator ◽  
Fundamental Parameters ◽  
The Road ◽  
Effective Implementation ◽  
Traffic Rate

Effective implementation of the EC Communication relating to urban mobility is dependent on adopting relevant indicators that will allow comprehensive assessment of the measures undertaken under the urban mobility plan. One of the fundamental parameters for this assessment is the equivalent sound level indicator, measured over the 24-hour period, used to evaluate the annoyance of the road traffic noise. Not only is its value important but also its variability. This paper reports the results of the analysis of traffic noise along a major road, performed using various descriptors. The data recorded continuously throughout the year by the traffic rate and noise monitoring terminal were used to construct the measurement database. Analysis of the results was performed for the period between March and June in 2011 and 2016. The road was renovated between 2013 and 2015. The noise variability assessment was conducted using classical and positional indicators. Measurement uncertainties were evaluated.

Equivalent sound level as a predictor for road traffic noise annoyance assessment

2021 ◽  
Vol 263 (2) ◽  
pp. 4622-4633
Author(s):  
Jan Felcyn ◽  
Anna Preis
Keyword(s):  
Road Traffic ◽  
Traffic Noise ◽  
Calculated Data ◽  
Sound Level ◽  
Time Structure ◽  
Single Type ◽  
Road Traffic Noise ◽  
The Road ◽  
Noise Annoyance ◽  
Sound Levels

Noise annoyance can be rated either in situ or in laboratory conditions. Regarding the , many papers indicate that only 30% of the variance in people's answers can be explained by sound level values. This value increases when a single type of noise is presented to participants in lab. However, the relationship between time structure of the noise stimulus and annoyance rating is still ambiguous. In this study road traffic noise stimuli with different time structure at three different sound levels were created. Moreover, the psychoacoustical characteristics of them were also computed. The calculated data was compared with results of the listening test in which participants rated each stimulus on the numerical ICBEN scale. Analysis showed that loudness and sound level are the dominant factors, they correlate quite well (~70%) with people's ratings. However, the different time structure of the road traffic noise at the same sound level did not evoke significantly different noise annoyance ratings. Since there are no standards available for loudness measurement, the sound level for the same type of noise remains the simplest factor to reliably predict its impact on people regarding noise annoyance.

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