Comparison of Low-Noise Air Nozzles: A Pilot Study

Author(s):  
Menekse Salar ◽  
M. Fehmi Capanoglu ◽  
Anjaneya Bandekar ◽  
Richard F. Sesek

Excessive noise is a global occupational health hazard with considerable social and physiological impact, including noise-induced hearing loss (NIHL) (Nelson et al., 2005). Noise is one of the most common occupational hazards in American workplaces. This study was performed in the Occupational Safety and Ergonomics Program’s Biomechanics Laboratory at Auburn University. The main purpose of this study was to compare the noise levels made by different air nozzles actually used by a bakery facility to nozzles whose manufacturers purported that they produce significantly less noise. Noise levels were determined using a sound level meter, which was positioned at ear level at distances of 5 and 10 feet. At the factory, air pressure (~100 psi) was used to push product downstream and to speed product cooling. The nozzles used were simple pipes or traditional air nozzles with side venting, but not of a “low noise” design. Two nozzles used by the factory were compared to three quieter nozzles. Nozzles were tested for both noise level and for air pressure (pushing force).

Author(s):  
OF Orikpete ◽  
◽  
DRE Ewim ◽  

With the projected growth in demand for commercial aviation, it is anticipated that there will be an increased environmental impact associated with noise, air quality, and climate change. Against this backdrop, the noise levels experienced by the residents of Mgbuoshimini Community due to helicopters takeoff and landing were studied. The study was carried out for 14 days at three different locations using a Class 2 Optimus sound level meter from 7am to 5pm daily. Analysis involved the equivalent noise levels, statistical measures for the background noise, aircraft flyover noise as well as the Noise Gap Index (NGI) . It was found that the equivalent noise levels of the background noise and aircraft flyover noise range from 67.7 dBA to 72.4 dBA and 88.4 dBA to 88.6 dBA respectively. The peak background noise and aircraft flyover noise ranged from 69.17 dBA to 79 dBA and 93.2 dBA to 94.8 dBA respectively. These values exceeded the recommended value of 60 dBA for residential areas. Two models to determine the NGI for both low noise areas and high noise areas were developed. A correlation coefficient of 0.70 and 0.88 were obtained between the actual and predicted values of NGI for both low and high noise areas. Therefore, it is recommended that buildings should be adequately insulated by use of noise-absorbing materials. Furthermore, environmentally friendly (quieter) aircrafts should be used by the airline company operating in that area


Author(s):  
Chun-Yip Hon ◽  
Illia Tchernikov ◽  
Craig Fairclough ◽  
Alberto Behar

Excessive noise levels are a prevalent issue in food processing operations and, although there have been numerous studies on occupational noise, no single study has used a concurrent mixed-methods approach. Employing this study design allows for an understanding of the level of convergence (similarity) between measured noise levels and workers’ attitudes and perceptions towards noise. This, in turn, allows for the identification of potential challenges with respect to the implementation of hearing conservation efforts. In this study, spot noise measurements were collected using a sound level meter. One-on-one interviews were conducted with workers to determine attitudes and perceptions towards noise in their workplaces. Subsequently, the results of the noise measurements (quantitative data) were integrated with the survey responses (qualitative data) to identify convergence. The majority of the noise measurements were found to exceed 85 dBA—the criterion mandated by the local occupational health and safety legislation. Although all study participants felt that it was noisy in the workplace, a large proportion of respondents indicated that the noise was not bothersome. With workers’ perception being contradictory to the measured noise levels, it is a challenge to implement hearing conservation measures unless changes are made to raise the awareness of the risks associated with excessive noise exposure.


2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P160-P160
Author(s):  
Angela P Black ◽  
James D Sidman

Objectives To demonstrate that neonatal ventilators produce high noise levels through bone conduction (BC) via endotracheal tubes, as well as air conduction (AC) from ambient noise. Methods A sound level meter was used to measure the noise levels 4 feet from the ventilator and in direct contact at the end of a balloon attached to the ETT to simulate the noise presented to the infant. 3 commonly used neonatal ventilators (Sensormedics 3100A, VIP Bird and Bunnell Jet) were examined. Results Noise levels were significantly higher (6 – 14 dB) at the end of the ETT than 4 ft from the ventilator for all ventilators studied. Conclusions Previous studies have shown high ambient noise levels in NICUs, but have failed to address the actual noise presented to the infant. ETT transmission of noise as a direct bone stimulus through the skull has been overlooked. This study has shown that high noise intensities are being presented not only as AC, but as BC to the infants though the ETT. This study demonstrates, therefore, that ear protection alone will not save these at-risk infants from hearing damage. More must be done to decrease noise exposure and develop quieter machines.


2018 ◽  
Vol 250 ◽  
pp. 02006
Author(s):  
Zaiton Haron ◽  
Darus Nadirah ◽  
Supandi Mohamad Afif ◽  
Yahya Khairulzan ◽  
Nordiana Mashros ◽  
...  

Transverse rumble strips (TRS) are commonly being installed to alert the drivers through sound and vibration effects. The sound produced affects the existing traffic noise level which caused noise annoyance to the nearby residents. This study aims to assess the traffic noise due to TRS at residential areas by determining the roadside noise levels, traffic and road characteristics and evaluating the relationship between these parameters. Middle overlapped (MO), middle layer overlapped (MLO) and raised rumbler (RR) TRS profiles with same thickness were selected. The measurements of roadside noise levels and skid resistance were conducted using sound level meter (SLM) and British pendulum tester (BPT) respectively. Traffic characteristics were evaluated using previous data measured using automatic traffic counter (ATC). In overall, MLO produced highest roadside noise levels with increase of 20.5dBA from baseline. Generally, the increase of roadside noise level due to TRS is strong with speed, weak to medium with skid resistance of TRS and no relationship with traffic volume. Based on three TRS profile types, MLO is not suitable to be installed on the roadways adjacent to the residential areas as the increase of roadside noise level is significant which is more than 5dBA compared to MO and RR.


Author(s):  
Ravinder Thaper ◽  
Murray Gibson ◽  
Mathew Reed ◽  
Wallace Morris ◽  
Aravind Reddy Putta

This study aims to assess using a smartphone app (DecibelX), as a noise measuring alternative to the more costly traditional use of measuring noise levels with a Sound Level Meter (SLM). The study compares the accuracy of the app to readings taken with a SLM and dosimeter, and also evaluates the app’s performance for pure tone and narrow band noise. And a usability study identifies strengths and weaknesses related to usability of the app.


2021 ◽  
Vol 12 (1) ◽  
pp. 51-62
Author(s):  
Nicholas OBI ◽  
◽  
Joy Sylvia OBI ◽  
Eziyi IBEM ◽  
Dickson NWALUSI ◽  
...  

Noise pollution and its concomitant effects on humans and environment has reached dangerous levels in many urban areas across the world. However, very little is known about the sources and effects of noise pollution within students’ hostels in a developing country like Nigeria. This study investigated urban noise pollution in residential neighbourhoods, using the Nnamdi Azikiwe University students’ off-campus accommodation in Awka, southeast Nigeria as the study area. Data were obtained through measurements of noise levels using sound level meter and by conducting a survey to gather feedback from 260 students in the study area. Descriptive statistics and Chi-Square tests were used to analyse the data; the results revealed mean noise levels of 89.8 dB(A) and 46.9 dB(A) during noisy and quiet periods, respectively. The main sources of noise were portable electricity generators, vehicular traffic and loudspeakers used by students and business operators; they were found to have deleterious effects such as low tolerance, headache, anger, lack of concentration and low productivity on the students. The study concludes by noting that to effectively minimize the effects of noise pollution within urban residential neighbourhoods in the study area and beyond, architects and urban planners should engage in proper land use zoning and the application of sound absorbing materials on walls and locating balconies of residential buildings away from noise sources. In addition, vegetation belts and sound barriers of earth mounds or wood, metal or concrete could also be constructed between the sources of noise and residential buildings, especially in the case of roadside communities.


2021 ◽  
Vol 7 (3) ◽  
pp. 560-574
Author(s):  
Mohamed N. Younes ◽  
Ali Z. Heikal ◽  
Akram S. Kotb ◽  
Haytham N. Zohny

The noise levels inside metro units are considered a significant problem that makes passengers suffer from severe damage, especially for those who use the metro periodically. This research evaluates the acoustic environment inside the metro car and studies factors affecting the noise levels inside metro units and developing models for estimate noise in the metro unit while moving between stations. Greater Cairo Metro (GCM) Line 1 has been selected as a case study. A sound level meter was used to measure the equivalent sound level in dBA and evaluate the noise inside metro units. The results indicate that the noise levels are unacceptable compared with the international noise exposure standards. The highest measured noise level inside metro units is 91.2 dBA. These unacceptable noise levels led to more investigation of factors that may affect noise levels inside metro units. Other data have been collected, such as the speed of the train and the track alignment details. The results showed that the noise increases with the increase of the train speed until the speed reaches a specific value, then it decreases depending on the maintenance status and the train type. In addition, the noise levels through curved underground tracks are higher than the levels along straight surface tracks by 18 dB(A). Doi: 10.28991/cej-2021-03091674 Full Text: PDF


2020 ◽  
Vol 30 (2) ◽  
pp. 14-31
Author(s):  
José Miguel Rivera Acevedo ◽  
Jonathan Agüero Valverde

The purpose of this study is to evaluate the noise generated by aeronautical operations around Juan Santamaría Airport and its compatibility with the land use and the proposed zoning around the airport. Aircraft noise can produce discomfort, interference with daily activities, and excessive vibrations; hence, land use planning around airports is of importance. Maps were prepared through computational models representing the noise levels generated by the operations of the airport. The operations were analyzed by aircraft type, schedules, and flight tracks, for 2013 and projections for: 2016, 2026, and 2036. Noise level data were collected with a sound level meter at 28 points surrounding the airport. Comparing the annual maps of 2013 and 2036 it was determined that 41,24 % of the analyzed area will present clearly perceivable increases (5 dB(A) to 10 dB(A)), and 1,36 % of the area will have double loudness increases (10 dB(A) to 14 dB(A)). The 2016 maps show locations where it is recommended to incorporate solutions in the construction regulation that reduce between 25 dB and 30 dB in the residential and scholar areas located within 65 dB(A) and 70 dB(A), such as Coco, Rincón Monge, Rincón Herrera, and Bajo Sorda. This finding is supported by field measurements. The proposed zoning was contrasted against the yearly day-night average sound level of 2036. The biggest issue of excessive aircraft noise is located near the west runway where a range above the 75 dB(A) is expected. Any edification of permanent residence must be banned in here.  


2020 ◽  
Vol 15 (2) ◽  
pp. 8-12
Author(s):  
A.S. Aremu ◽  
T.K. Amao ◽  
O.A. Mokuolu

This study investigated the effect of different particle sizes of sand bed anti-vibration mount on transmitted noise from a portable on-site electricity generator. Ten sand bed anti-vibration mounts, 650mm x 650mm in cross section and 75mm thickness were prepared with particle sizes ranging from 0.09 to 2.30mm. Noise measurements were taken in the four cardinal directions using Extech HD600 digital sound level meter. The results of the study showed that the ability of the sand particles to dampen vibration noise from the portable electricity generator reduces with increase in particle size. The sand bed anti-vibration mounts reduced noise levels by 0.11 to 2.78 dB(A). However, fine sand bed of particle size 0.09mm and 0.15mm exhibited superiority in noise reduction over all other sand beds. In order to achieve appreciable noise reduction, the use of ISO 14688-1:2002 fine sand category is recommended as anti-vibration mount in combination with other damping methods. Keywords: Electricity generator, noise, sand, particle size and attenuation


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