Blow-Down Valve Noise and Interactions With Downstream Orifice Plates

2003 ◽  
Author(s):  
Denis G. Karczub ◽  
Fred W. Catron ◽  
Allen C. Fagerlund
Keyword(s):  
Noise Exposure ◽  
Control Valve ◽  
Low Noise ◽  
Noise Levels ◽  
Exposure Limits ◽  
Blow Down ◽  
Gas Processing ◽  
The Impact ◽  
Acoustic Fatigue ◽  
Infrequent Event

In a blow-down situation as might occur at a natural gas processing facility, noise levels are very high and significantly exceed the noise levels one would normally associate with a control valve. As the blow-down operation is an infrequent event, this may be permissible but requires consideration of the duration of these high noise levels to ensure that occupational noise exposure limits and acoustic fatigue limits are not exceeded. Tests of noise levels due to an 8-inch control valve in a 12-inch pipeline under blow-down conditions are compared here with noise level predictions based on the IEC standard. Consideration is also given to the impact of placing an orifice plate downstream of the control valve as is often done to reduce pressure drop across the valve in the expectation that control valve noise levels will be reduced. Simple orifice plates often installed by plant operators to achieve this goal are shown to have an adverse impact, and it is shown that a multi-hole diffuser or low-noise control valve should instead be used.

scholarly journals The Impact of Thin Asphalt Layers as a Road Traffic Noise Intervention in an Urban Environment

2021 ◽  
Vol 13 (22) ◽  
pp. 12561
Author(s):  
Ablenya Grangeiro de Barros ◽  
Jarl K. Kampen ◽  
Cedric Vuye
Keyword(s):  
Noise Exposure ◽  
Road Traffic ◽  
Traffic Noise ◽  
Low Noise ◽  
Urban Environments ◽  
Comfort Level ◽  
Road Traffic Noise ◽  
Acoustic Measurements ◽  
Noise Levels ◽  
The Impact

Low-noise thin asphalt layers (TALs) are a feasible solution to mitigate road traffic noise in urban environments. Nevertheless, the impacts of this type of noise intervention are reported mostly regarding noise levels, while non-acoustic aspects influencing the population perception are still little-known. This study investigates the implementation of TALs in two streets of Antwerp, Belgium. The effectiveness of the intervention was measured via noise modelling and acoustic measurements of road traffic noise. A reduction of 2.8 dB in noise exposure was observed in Lden and Lnight, while SPB measurements showed decreases up to 5.2 dB on the roadside. The subjective impacts of the TALs were evaluated via self-administered surveys and compared to results from control streets. The annoyance indicators were positively impacted by the TALs implementation, resulting in annoyance levels similar or lower than in the control streets. The TALs did not impact the reported physical complaints, sleep quality, and comfort level to perform activities.

Status - International Space Station (ISS) Crewmembers' Noise Exposures

2021 ◽  
Vol 263 (4) ◽  
pp. 2740-2754
Author(s):  
Jose Limardo ◽  
Christopher S. Allen ◽  
Richard W. Danielson ◽  
Andrew J. Boone
Keyword(s):  
International Space Station ◽  
Noise Exposure ◽  
Space Station ◽  
Monitoring Program ◽  
Conservation Strategies ◽  
Exposure Limits ◽  
International Space ◽  
Exposure Monitoring ◽  
The Impact ◽  
Dosimetry Data

Environmental noise in space vehicles, caused by onboard equipment and crew activities, has generated concerns for crew health and safety since early U.S. space missions. The International Space Station (ISS) provides a unique environment where acoustic conditions can be monitored while crewmembers from the U.S. and their international partners work and live for as long as 6 to 12 consecutive months. This review of acoustic dosimetry data collected to date reveals that the noise exposure limits of NASA's stringent noise constraint flight rule have been exceeded in 41% of these dosimetry measurements since ISS Increment 17 (2008), with undefined impacts to crew. These measurements do not take into account the effects of hearing protection devices worn by the crew. The purpose of this paper is to provide an update on ISS noise exposure monitoring approaches and hearing conservation strategies that include acoustic dosimetry data collected since the ISS Increment 55 mission (April 2018). Future directions and recommendations for the ISS noise exposure monitoring program will also be presented, including research initiatives aimed at better defining the impact of ISS noise on crew health and performance.

Work-related road safety: The impact of the low noise levels produced by electric vehicles according to experienced drivers

2020 ◽  
Vol 121 ◽  
pp. 580-588 ◽  
Author(s):  
María del Carmen Pardo-Ferreira ◽  
Juan Carlos Rubio-Romero ◽  
Fuensanta Carmen Galindo-Reyes ◽  
Antonio Lopez-Arquillos
Keyword(s):  
Electric Vehicles ◽  
Road Safety ◽  
Low Noise ◽  
Noise Levels ◽  
Work Related ◽  
The Impact

Hearing Protection With Integrated In-Ear Dosimetry: A Noise Dose Study

2012 ◽  
Author(s):  
Melissa A. Theis ◽  
Hilary L. Gallagher ◽  
Richard L. McKinley ◽  
Valerie S. Bjorn
Keyword(s):  
Noise Exposure ◽  
National Standards ◽  
Hearing Protection ◽  
Octave Band ◽  
Noise Levels ◽  
Exposure Limits ◽  
Group Data ◽  
Dose Study ◽  
Hearing Protector ◽  
Naval Air Systems Command

Military personnel working in high noise environments can be exposed to continuous noise levels up to 150 dB. United States (US) Department of Defense (DoD) Hearing Conservation Programs (HCPs) [1–3] set safe noise exposure limits to reduce the risk for noise induced hearing loss. These daily noise exposure limits were based on ambient noise levels and the duration of time spent in that noise environment. Current dosimeters, worn on the lapel of personnel and at least one system worn under a hearing protector, were designed to measure noise levels and calculate noise dose, but do not provide a validated measure of noise dose external to or under a hearing protector. Noise dose under hearing protectors can be estimated by subtracting the real ear attenuation (REAT) data, collected in accordance with the American National Standards Institute (ANSI) S12.6 [4], at each octave band from the ambient octave band noise. This procedure gives accurate results for group data, but does not account for individual variations in effective attenuation. To address this issue, the US Naval Air Systems Command (NAVAIR) led the development of ship suitable in-ear dosimetry integrated into a hearing protector, and co-sponsored an effort executed by the Air Force Research Laboratory (AFRL) to calibrate in-ear noise dose readings. This was accomplished by conducting human noise exposure experiments, with and without hearing protection, which calculated noise dose from temporary threshold shifts (TTS) in hearing. Ten subjects participated in the study. Noise levels were 91, 94, and 97 dB for up to 2 hrs, 1 hr, and 30 minutes respectively. These exposure levels were well within US DoD safe noise exposure guidelines (DoD HCP) [1–3]. Data will be presented describing the open and occluded (protected) ear TTS response to noise dose achieved by subjects in the experiment. Preliminary findings indicate that human subject data is extremely important in developing and validating calibration factors for any type of noise dosimeter but is especially important for in-ear dosimetry. Results from this study demonstrated that the REAT noise dose estimations and the in-ear dosimetry earplugs consistently overestimated the effective noise dose received by subjects. However, more than 10 subjects are required to improve the confidence level of the estimated calibration factor.

scholarly journals Effects of an ambient learning display on noise levels and perceived learning in a secondary school

2021 ◽  
Author(s):  
Bernardo Tabuenca ◽  
Dirk Börner ◽  
Marco Kalz
Keyword(s):  
Teaching And Learning ◽  
Noise Exposure ◽  
Lessons Learned ◽  
Learning Performance ◽  
Perceived Learning ◽  
Noise Levels ◽  
Negative Effects ◽  
Ambient Displays ◽  
Teachers And Students ◽  
The Impact

Recent reviews addressing the impact of noise exposure in teaching and learning situations conclude negative effects on learning performance. Providing objective real-time feedback on noise is key for teachers and students to adjust it into suitable levels. This experimental work presents the results from a study exploring the visual feedback based on noise level and the impact on students’ (n = 198) perceived learning performance collected in 24 sessions. The results suggest persuasive effects of the ambient display on the groups and an improvement of noise awareness in students. Measurements of perceived learning-performance, and perceived noise were collected and correlated with the objective noise samples concluding poorer perceived learning performance in noisiest groups. Finally, implications for further research as well as lessons learned to moderate noise levels in classrooms using ambient displays are discussed.

One Stage and Two Stage Vibration Isolators as Applied to High Speed Textile Spindles to Achieve Noise Reduction

1978 ◽  
Vol 100 (1) ◽  
pp. 33-40 ◽  
Author(s):  
L. W. Foster
Keyword(s):  
Low Noise ◽  
Single Stage ◽  
Sound Power ◽  
Octave Band ◽  
Noise Levels ◽  
Two Stage ◽  
Noise And Vibration ◽  
Vibration Isolators ◽  
One Stage ◽  
The Impact

The operation of ring spinning frames in textile mills can create spinning room noise levels of 90 to 95 dBA. The spindle bobbin mechanisms (generally 300 to 400 per machine) which are operated at spindle speeds of 6,000 to 14,000 rpm are major sources of noise in this type of machinery. The rotating unbalance force in the spindle-bobbin mechanism creates high frequency vibrations in the spindle blade and in the spindle bolster which contains the bearings on which the blade rotates. The vibrations generated by the spindle bobbin mechanism and the bearings are transmitted through the spindle bolster to the rail structure of the spinning frame where they cause sand energy to be radiated. This paper describes the use of two types of elastomeric vibration isolators located between the spindle bolster and the rail to achieve reductions of vibration and noise levels associated with the spindle-bobbin-rail subsystem of spinning frames. The two types of elastomeric isolators employed are: (1) a single-stage isolator where a bonded elastomeric mounting of annular design is placed between the bolster and the rail, and (2) a two-stage isolator which incorporates an annular intermediate mass element between two annular elastomeric sections that provide the interfaces to the spindle and to the rail. The two stage isolator is a novel design for rotating spindle type applications and employs the classical two stage isolator principle to achieve greater attenuation of vibrations. While it has been known for some time that single stage elastomeric isolators provide an effective means of reducing vibrations and noise in textile spinning and twisting machines, recent emphasis on reducing machine noise levels has motivated increased effort to better describe and apply elastomeric isolators. The two-stage isolator concept has been employed in an attempt to achieve higher operating speeds and, therefore, higher productivity while keeping noise levels within acceptable limits. In order to demonstrate the degrees of noise and vibration reductions that can be attained using the two types of isolators in comparison with the non-isolated or hard-mounted spindle, tests were performed using a single oil base type spinning spindle with a full bobbin. The spindle-bobbin mechanism was mounted to a representative rail by the three mounting methods described previously and operated at speeds of 11,000 rpm and 14,000 rpm in a reverberation room. Octave band sound power level measurements and one-tenth octave band sound pressure measurements were made to compare the performance of the mounting methods. These measurements were made using six microphones at different locations and sampling their output signals at a high rate over an extended interval of time. One-tenth octave horizontal and vertical rail acceleration responses were obtained concurrently with the noise responses. These noise and vibration responses are presented and discussed in the paper. The results show that the elastomeric isolators provide significant reductions in rail vibration response levels in the spindle bearing vibration frequency range of 500 to 2000 Hz. The corresponding overall sound power levels for the two operating speeds when using one stage isolators were 8 to 18 dBA below the hard-mounted spindle condition. When using the two-stage isolator, the overall sound power levels for the two operating speeds were 9 and 20 dBA below the hard mounted spindle condition. The results demonstrate the importance of properly designing the mounting to tune the system for low noise responses while minimizing the impact on other operatonal criteria such as spindle static deflection and dynamic motion. A discussion of the isolator design parameter trade-offs is presented along with comments regarding the limitations of the testing and the constraints involved in predicting the noise level reduction to be expected for a whole spinning frame.

scholarly journals Mitigasi dampak kebisingan bandara terhadap kehidupan pemukiman sekitar bandara SSK II Pekanbaru

Jurnal Zona ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 91-106
Author(s):  
Eko Hendi Saputra ◽  
Yusni Ikhwan Siregar ◽  
Hafidawati Hafidawati
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Noise Exposure ◽  
Pressure Level ◽  
Noise Attenuation ◽  
Residential Areas ◽  
Noise Levels ◽  
Residential Communities ◽  
The People ◽  
The Impact

This study aims to determine the level of noise caused by flight activities at Sultan Syarif Kasim II Airport Pekanbaru, analyze noise levels that occur due to flight activities at Sultan Syarif Kasim II Airport Pekanbaru and analyze efforts to control the negative impact of airport noise on the living environment of community settlements. around Sultan Syarif Kasim II Airport Pekanbaru. This research uses field observation method, which is making direct observations at the research location by looking at the condition of the location and the suitability of the location which is the sampling point of the study (the noise level boundary at Sultan Syarif Kasim II Airport). Observations were made for 16 hours (Ls) at an interval of 06.00 - 22.00. Measurement of sound pressure level is carried out on holidays (Sunday) and weekdays (Monday), which starts on November 1, November 2, November 8, and November 9, 2020, which is carried out in residential areas around Sultan Syarif Kasim II Airport Pekanbaru, which are spread across 6 measurement points where the measurement of sound pressure level is done in duplicate, namely: Jl. Kaswari (point 1), Jl. Rawa Indah II (Point 2), Jl. Rawa Indah III (Point 3), Jl. Cinnamon (Point 4), Jl. Pahlawan Kerja gg.Pala 49 (Point 5) and Jl. Nur Asiyah (Point 6) The results of the processing of noise measurement data were made of a mapping model using surfer 11 software and to clarify the noise description at the sampling location, the map of the results of surfer 11 software processing was plotted on the airport area map.     Based on the results of measurements of noise levels around Sultan Syarif Kasim II airport, it is known that the location of point 1 (Jl. Rawa Indah II) experienced the highest noise exposure. These results indicate the location of point 1 should receive serious attention for the people who live around the airport, because the impact of airport noise has the potential to negatively affect the lives of residential communities. From the observations, it was also known that the level of noise attenuation was still low, both in terms of trees around the settlement and height, walls and fences were still not effective at reducing noise.         Based on the results of measurements of noise levels around Sultan Syarif Kasim II airport, it is known that the location of point 1 (Jl. Rawa Indah II) experienced the highest noise exposure. These results indicate that the location of point 1 should receive serious attention for the people who live around the airport, because the impact of airport noise has the potential to negatively affect the lives of residential communities. From the observations, it was also known that the level of noise attenuation was still low, both in terms of trees around the settlement and height, walls and fences were still not effective at reducing noise.         From the results of the research that has been done, several mitigation strategies can be formulated to reduce noise levels around Sultan Syarif Kasim II airport. Planting plants in accordance with the needs of controlling or reducing noise in human settlements. Tree categories suitable for planting in residential areas around the airport are: shady trees that can be planted tightly or with lots of leaves that can grow to a height of about 4 - 15 m (such as acacia, mahogany, flamboyant, ironwood or banyan trees, bamboo or cypress)

Noise Levels Among Spectators at an Intercollegiate Sporting Event

2014 ◽  
Vol 23 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Beau England ◽  
Jeffery Blythe Larsen
Keyword(s):  
Otoacoustic Emissions ◽  
Noise Exposure ◽  
Sporting Events ◽  
Noise Levels ◽  
Hearing Sensitivity ◽  
Distortion Product ◽  
Sound Levels ◽  
Basketball Game ◽  
Hearing Thresholds ◽  
The Impact

Purpose The intensity of noise levels in a basketball arena during games, as well as the hearing sensitivity of attendees, was measured for the purpose of assessing the impact of the noise on hearing thresholds. Method Noise levels at 10 intercollegiate basketball games were measured with a dosimeter affixed on the shoulders of attendees. Hearing thresholds and distortion product otoacoustic emissions were measured for 20 participants just before attending a basketball game and within an hour of the end of the game to determine whether changes in hearing thresholds resulted from exposure to the sound levels within the arena during the games. Results Participants demonstrated temporary shifts in pure-tone thresholds and reductions in the intensity of their otoacoustic emissions after attendance at 1 of the basketball games. Dosimeter measurements showed that noise at 6 of the 10 basketball games exceeded acceptable intensity levels when compared with a national workplace noise exposure standard. Conclusion Although noise intensities, on average, did not exceed workplace exposure standards, universities would be wise to be proactive in warning spectators about the potential dangers of noise exposure at sporting events, make earplugs available to interested spectators, and implement a hearing conservation program for employees working in noise.

scholarly journals Acoustic Predictions in Industrial Spaces Using a Diffusion Model

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Alexis Billon ◽  
Judicaël Picaut ◽  
Vincent Valeau ◽  
Anas Sakout
Keyword(s):  
Diffusion Equation ◽  
Noise Exposure ◽  
Low Noise ◽  
Working Environment ◽  
Noise Levels ◽  
Sound Sources ◽  
Flexible Tool ◽  
Virtual Factory ◽  
Prediction Tools ◽  
Computation Load

Industrial spaces are known to be very noisy working environment. This noise exposure can be uncomfortable, tiring, or even harmful, at worst. Industrial spaces have several characteristics: they are often huge flat volumes fitted with many obstacles and sound sources. Moreover, they are usually surrounded by rooms where low noise levels are required. The existing prediction tools can seldom model all these phenomena accurately. In this paper, a prediction model based on a diffusion equation is presented. The successive developments carried out to deal with the various propagating phenomena met in industrial spaces are shown. For each phenomenon, numerical or experimental examples are given to highlight the validity of this model. It is also shown that its computation load is very little in comparison to ray-tracing-based methods. In addition, this model can be used as a reliable and flexible tool to study the physics of the coupling between rooms. Finally, an application to a virtual factory is presented.

A Fuzzy Approach for Modelling the Effects of Noise Pollution on Human Performance

2004 ◽  
Vol 8 (4) ◽  
pp. 442-450 ◽  
Author(s):  
Zaheeruddin ◽  
◽  
V. K. Jain ◽  
Keyword(s):  
Human Performance ◽  
Noise Exposure ◽  
Fuzzy Model ◽  
Noise Pollution ◽  
Industrial Workers ◽  
Work Efficiency ◽  
Noise Levels ◽  
Exposure Limit ◽  
The Impact ◽  
Lower Noise

In this paper, an attempt has been made to develop a fuzzy model for determining the work efficiency of humans as a function of noise level, exposure time, and the type of task. The modelling technique is based on the concept of fuzzy logic, which offers a convenient way of representing the relationships between the inputs and outputs of a system in the form of IF-THEN rules. It has been established on the basis of surveys that the impact of noise on work efficiency depends to a large extent on the type of tasks. The complex tasks get significantly affected even at much lower noise levels whereas the simple tasks remain unaffected up to very high noise levels. In addition, the duration of noise exposure is an important factor in determining the work efficiency. Finally, we have compared our model results with the deduction based on the criterion of Safe Exposure Limit recommended for industrial workers.

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