Measurement of Total Sound Energy Density in Enclosures at Low Frequencies Abstract of Paper
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Industrial Noise Control and Acoustics
Industrial Noise Control and Acoustics Randall F. Barron Louisiana Tech University Ruston, Louisiana, U.S.A. Marcel Dekker, Inc. New York • Basel Copyright © 2001 by Marcel Dekker, Inc. All Rights Reserved. Copyright © 2003 Marcel Dekker, Inc. LibraryofCongressCataloging-in-PublicationData AcatalogrecordforthisbookisavailablefromtheLibraryofCongress. ISBN:0-8247-0701-X Thisbookisprintedonacid-freepaper. Headquarters MarcelDekker,Inc. 270MadisonAvenue,NewYork,NY10016 tel:212-696-9000;fax:212-685-4540 EasternHemisphereDistribution MarcelDekkerAG Hutgasse4,Postfach812,CH-4001Basel,Switzerland tel:41-61-260-6300;fax:41-61-260-6333 WorldWideWeb http://www.dekker.com The publisher offers discounts on this book when ordered in bulk quantities, For more information, write to Special Sales/Professional Marketing at the headquarters address above. Copyright # 2003 by Marcel Dekker, Inc. All Rights Reserved. Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming, and recording, or by any information storage retrieval system, without permission in writing from the publisher. Current printing (last digit): 10987654321 PRINTED IN THE UNITED STATES OF AMERICA Copyright © 2003 Marcel Dekker, Inc. Preface Since the Walsh-Healy Act of 1969 was amended to include restrictions on the noise exposure of workers, there has been much interest and motivation in industry to reduce noise emitted by machinery. In addition to concerns about air and water pollution by contaminants, efforts have also been direc- ted toward control of environmental noise pollution. In response to these stimuli, faculty at many engineering schools have developed and introduced courses in noise control, usually at the senior design level. It is generally much more effective to design ‘‘quietness’’ into a product than to try to ‘‘fix’’ the noise problem in the field after the product has been put on the market. -
Definition and Measurement of Sound Energy Level of a Transient Sound Source
J. Acoust. Soc. Jpn. (E) 8, 6 (1987) Definition and measurement of sound energy level of a transient sound source Hideki Tachibana,* Hiroo Yano,* and Koichi Yoshihisa** *Institute of Industrial Science , University of Tokyo, 7-22-1, Roppongi, Minato-ku, Tokyo, 106 Japan **Faculty of Science and Technology, Meijo University, 1-501, Shiogamaguti, Tenpaku-ku, Nagoya, 468 Japan (Received 1 May 1987) Concerning stationary sound sources, sound power level which describes the sound power radiated by a sound source is clearly defined. For its measuring methods, the sound pressure methods using free field, hemi-free field and diffuse field have been established, and they have been standardized in the international and national stan- dards. Further, the method of sound power measurement using the sound intensity technique has become popular. On the other hand, concerning transient sound sources such as impulsive and intermittent sound sources, the way of describing and measuring their acoustic outputs has not been established. In this paper, therefore, "sound energy level" which represents the total sound energy radiated by a single event of a transient sound source is first defined as contrasted with the sound power level. Subsequently, its measuring methods by two kinds of sound pressure method and sound intensity method are investigated theoretically and experimentally on referring to the methods of sound power level measurement. PACS number : 43. 50. Cb, 43. 50. Pn, 43. 50. Yw sources, the way of describing and measuring their 1. INTRODUCTION acoustic outputs has not been established. In noise control problems, it is essential to obtain In this paper, "sound energy level" which repre- the information regarding the noise sources. -
Monitoring of Sound Pressure Level
1. INTRODUCTION Noise is one of the main environmental problems of modern life and it is inseparable from human activities, urban and technological growth. National and international standards provide for a minimum of acoustic comfort for coexistence between man and industrial development. That's why a study of noise emission and environmental noise at the PALAGUA - CAIPAL Field was carried out; samples of measurements were taken in specific (punctual) manner to meet the sound pressure level (SPL) with a duration of five minutes per sample/measurement for noise measurements and 15 minutes for ambient or environmental noise in each direction: (north, east, south, west and vertical). The result of these measurements was compared with the maximum permissible noise emission and environmental noise standards stated in Resolution 627 of 2006 Ministry of Environment, Housing, and Territorial Development (MAVDT) and thus it was verified that they comply with environmental regulations in the PALAGUA - CAIPAL Field. 1 INFORME DE LABORATORIO 0860-09-ECO. NIVELES DE PRESIÓN SONORA EN EL AREA DE PRODUCCION CAMPO PALAGUA - CAIPAL PUERTO BOYACA, BOYACA. NOVIEMBRE DE 2009. 2. OBJECTIVES • To evaluate the emission of noise and environmental noise encountered in the PALAGUA - CAIPAL Gas Field area, located in the municipality of Puerto Boyacá, Boyacá. • To compare the obtained sound pressure levels at points monitored, with the permissible limits of resolution 627 of the Ministry of Environment, SECTOR C: RESTRICTED INTERMEDIATE NOISE, which allows a maximum of 75 dB in the daytime (7:01 to 21:00) and 70 dB in the night shift (21:01 to 7: 00 hours) 2 INFORME DE LABORATORIO 0860-09-ECO. -
Noise Exposure Limit for Children in Recreational Settings: Review of Available Evidence
Noise exposure limit for children in recreational Make Listening Safe settings: review of WHO available evidence This document presents a review of existing evidence on risk of noise induced hearing loss due to exposure to sounds in recreational settings, with respect to children. The evidence was used to stimulate discussion for determination of exposure limits (in children) to be applied to standards for personal audio devices. The review has been undertaken by February 2018 Dr Benjamin Roberts under the supervision of Dr Richard Neitzel, in collaboration with WHO. The document has been reviewed by members of WHO expert group on exposure limits for NIHL in recreational settings. Noise exposure limit for children in recreational settings: review of available evidence Authors: Dr Benjamin Roberts Dr Richard Neitzel Reviewed by: Dr Brian Fligor Dr Ian Wiggins Dr Peter Thorne 1 Contents List of Tables 1 List of Figures 1 Definitions and Acronyms ............................................................................................................................. 2 Executive Summary ....................................................................................................................................... 3 Background and Significance ........................................................................................................................ 4 How Noises is Assessed............................................................................................................................. 5 Overview of the Health -
Derivation of the Sabine Equation: Conservation of Energy
UIUC Physics 406 Acoustical Physics of Music Derivation of the Sabine Equation: Conservation of Energy Consider a large room of volume V = HWL (m3) with perfectly reflecting walls, filled with a uniform, steady-state (i.e. equilibrium) acoustic energy density wrtfa ,, at given frequency f (Hz) within the volume V of the room. Uniform energy density means that a given time t: 3 waa r,, t f w t , f constant (SI units: Joules/m ). The large room also has a small opening of area A (m2) in it, as shown in the figure below: H V A I rt,, f ac nAˆˆ, An W L In the steady-state, the rate of acoustical energy Wa input e.g. by a point sound source within the large room equals the rate at which acoustical energy is “leaking” out of the room through the hole of area A, i.e. the acoustical power input by the sound source in the room into the room = the acoustical power leaving the room through the hole of area A. In this idealized model of a room with perfectly reflecting walls, the hole of area A thus represents absorption of sound in a real room with finite reflectivity walls, i.e. walls that have some absorption associated with them. Suppose at time t = 0 the sound source in the room {located far from the hole} is turned off. Since the sound energy density is uniform in the room, the sound energy contained in the room Wtf,,,, wrtfdrwtf 33 drwtfV , will thus decrease with time, since aaVV a a acoustical energy is (slowly) leaking out of the room through the opening of area A. -
Changes and Challenges in Environmental Noise Measurement * Philip J Dickinson Massey University Wellington, New Zealand
CHANGES AND CHALLENGES IN ENVIRONMENTAL NOISE MEASUREMENT * Philip J Dickinson Massey University Wellington, New Zealand Many changes have occurred in the last seventy years, not least of which are the changes in our environment and interdependently our intellectual and technological development. Sound measurement had its origins in the 1920s at a time when people were still traveling by horse and cart or on steam trains and few people used electricity. The technology of electronics was in its infancy and our predecessors had limited tools at their disposal. Nevertheless, they provided the basis on which we rely for our present day sound measurements. Since then we have come far, but we still await a solution for the lack of accuracy we have come to accept. THE BEGINNINGS independent of frequency and temperature, it was convenient to use a power (or logarithmic) series for its description based on the power developed by a one volt sinusoid across a mile of standard cable. This measure was called the Transmission Unit TU (Martin 1924) Harvey Fletcher (whom this author is very privileged to be able to have called a friend) studied the reactions of (it is believed) 23 of his colleagues to sound in a telephone earpiece generated by an a.c. voltage. He came up with the idea of a “sensation unit” SU, based on a power series compared to the voltage that produced the minimum sound audible. Harvey initially called this the “Loudness Unit” (Fletcher 1923) but later changed his mind following his work on loudness with Steinberg (Fletcher and Steinberg 1924). -
Table Chart Sound Pressure Levels Level Sound Pressure
1/29/2011 Table chart sound pressure levels level… Deutsche Version • Decibel Table − Loudness Comparison Chart • Table of Sound Levels (dB Scale) and the corresponding Units of Sound Pressure and Sound Intensity (Examples) To get a feeling for decibels, look at the table below which gives values for the sound pressure levels of common sounds in our environment. Also shown are the corresponding sound pressures and sound intensities. From these you can see that the decibel scale gives numbers in a much more manageable range. Sound pressure levels are measured without weighting filters. The values are averaged and can differ about ±10 dB. With sound pressure is always meant the effective value (RMS) of the sound pressure, without extra announcement. The amplitude of the sound pressure means the peak value. The ear is a sound pressure receptor, or a sound pressure sensor, i.e. the ear-drums are moved by the sound pressure, a sound field quantity. It is not an energy receiver. When listening, forget the sound intensity as energy quantity. The perceived sound consists of periodic pressure fluctuations around a stationary mean (equal atmospheric pressure). This is the change of sound pressure, which is measured in pascal (Pa) ≡ 1 N/m2 ≡ 1 J / m3 ≡ 1 kg / (m·s2). Usually p is the RMS value. Table of sound levels L (loudness) and corresponding sound pressure and sound intensity Sound Sources Sound PressureSound Pressure p Sound Intensity I Examples with distance Level Lp dBSPL N/m2 = Pa W/m2 Jet aircraft, 50 m away 140 200 100 Threshold of pain -
A Parametric Analysis and Sensitivity Study of the Acoustic Propagation for Renewable Energy
OCS Study BOEM 2020-011 A Parametric Analysis and Sensitivity Study of the Acoustic Propagation for Renewable Energy US Department of the Interior Bureau of Ocean Energy Management Office of Renewable Energy Programs OCS Study BOEM 2020-011 A Parametric Analysis and Sensitivity Study of the Acoustic Propagation for Renewable Energy Sources 10 February 2020 Authors: Kevin D. Heaney, Michael A. Ainslie, Michele B. Halvorsen, Kerri D. Seger, Roel A.J. Müller, Marten J.J. Nijhof, Tristan Lippert Prepared under BOEM Award M17PD00003 Submitted by: CSA Ocean Sciences Inc. 8502 SW Kansas Avenue Stuart, Florida 34997 Telephone: 772-219-3000 US Department of the Interior Bureau of Ocean Energy Management Office of Renewable Energy Programs DISCLAIMER Study concept, oversight, and funding were provided by the U.S. Department of the Interior, Bureau of Ocean Energy Management (BOEM), Environmental Studies Program, Washington, D.C., under Contract Number M15PC00011. This report has been technically reviewed by BOEM, and it has been approved for publication. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of the U.S. Government, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. REPORT AVAILABILITY To download a PDF file of this report, go to the U.S. Department of the Interior, Bureau of Ocean Energy Management Data and Information Systems webpage (http://www.boem.gov/Environmental-Studies- EnvData/), click on the link for the Environmental Studies Program Information System (ESPIS), and search on 2020-011. The report is also available at the National Technical Reports Library at https://ntrl.ntis.gov/NTRL/. -
Sound Level Descriptors
SOUND LEVEL DESCRIPTORS in Alphabetical Order FHWA-HEP-17-053 The L10(t) is a statistical descriptor of the sound level exceeded for 10% of the time of the measurement period (t). It can be obtained using short-term measurements; however, it cannot be accurately added to or subtracted from other L10 measures or other descriptors. Typically, the L10 is about 3 dB(A) above the LEQ(t). This measurement is permitted for use by the Federal High- way Administration. The L50(t) is a statistical descriptor of the sound level exceeded for 50% of the time of the measurement period (t). The L90(t) is a statistical descriptor of the sound level exceeded 90% of the time of the measurement period (t). This is considered to represent the background noise without the source in question. Where the noise emissions from a source of interest are constant (such as noise from a fan, air conditioner or pool pump) and the ambient noise level has a degree of variability (for example, due to traffic noise), the L90 descriptor may adequately describe the noise source. The LDEN or CNEL (Community Noise Exposure Level) descriptor describes a receiver's cumulative noise exposure from all events over a full 24 hours [LEQ(24)], with a 5-dB penalty applied to evening hours (between 7 PM and 10 PM), and a 10-dB penalty applied to nighttime hours (between 10 PM and 7 AM). The LDEN is computed as follows: LDEN = LAE + 10*log10 (NDAY + 3*NEVE + 10*NNIGHT) - 49.4 (dB) NDAY = Number of vehicle pass-bys between 7 AM and 7 PM NEVE = Number of vehicle pass-bys between 7 PM and 10 PM NNIGHT = Number of vehicle pass-bys between 10 PM and 7 AM 49.4 = A normalization constant which spreads the acoustic energy associated with highway vehicle pass-bys over a 24-hour period, i.e., 10*log10 (86,400 seconds per day) = 49.4 dB. -
Noise Glossary of Terms
Noise Glossary of Terms Absorption The property of all materials that allows a reduction in the amount of sound energy reflected from it. Incident sound energy is turned into heat inside the material during the absorption process. Absorption coefficient A measure of the sound-absorbing ability of a surface. It is defined as the fraction of incident sound energy absorbed or otherwise not reflected by a surface. The value of the absorption coefficient varies in the range from about 0.01 for marble to 1.0 for a room covered in foam sound wedges. Accuracy The degree with which a measuring instrument obtains the "true" result. When noise measurements are carried out using a noise meter this will be the dB value representing the true sound pressure plus or minus the error at the time of the measurement. The acceptable limits for the accuracy (or error) of an instrument are usually specified in national and international standards issued by independent bodies such as ANSI or IEC. For noise meters they will cover frequency response, effect of the direction of sound arriving at the instrument and other various environmental effects such as temperature and ambient air pressure. Acoustics The science of sound, including the generation, transmission and effects of sound waves, both audible and inaudible. Acoustic trauma The damage to the hearing mechanism caused by a sudden burst of high-energy noise such as a blast or gun fire. The term is usually considered to be caused by a single impulsive event with a very high peak sound level. Action level (dB) The 8 hour continuous notional noise level at which the employer must undertake certain duties of care for exposed workers. -
DRAFT Soundscape and Modeling Metadata Standard Version 2
DRAFT Soundscape and Modeling Metadata Standard Version 2 Atlantic Deepwater Ecosystem Observatory Network (ADEON): An Integrated System Contract: M16PC00003 Jennifer Miksis-Olds Lead PI John Macri Program Manager 7 July 2017 Approvals: _________________________________ _ 7 July 2017___ Jennifer Miksis-Olds (Lead PI) Date _________________________________ __7 July 2017___ John Macri (PM) Date Soundscape and Modeling Metadata Standard Version: 2ND DRAFT Date: 7 July 2017 Ainslie, M.A., Miksis‐Olds, J.L., Martin, B., Heaney, K., de Jong, C.A.F., von Benda‐Beckman, A.M., and Lyons, A.P. 2017. ADEON Soundscape and Modeling Metadata Standard. Version 2.0 DRAFT. Technical report by TNO for ADEON Prime Contract No. M16PC00003. 1 Contents Contents .............................................................................................................................................. 2 Abbreviations ...................................................................................................................................... 4 1. Introduction .................................................................................................................................... 5 ADEON project ................................................................................................................................... 5 Objectives............................................................................................................................................ 5 ADEON project objectives .............................................................................................................. -
Sound Pressure and Particle Velocity Measurements from Marine Pile Driving at Eagle Harbor Maintenance Facility, Bainbridge Island WA
Suite 2101 – 4464 Markham Street Victoria, British Columbia, V8Z 7X8, Canada Phone: +1.250.483.3300 Fax: +1.250.483.3301 Email: [email protected] Website: www.jasco.com Sound pressure and particle velocity measurements from marine pile driving at Eagle Harbor maintenance facility, Bainbridge Island WA by Alex MacGillivray and Roberto Racca JASCO Research Ltd Suite 2101-4464 Markham St. Victoria, British Columbia V8Z 7X8 Canada prepared for Washington State Department of Transportation November 2005 TABLE OF CONTENTS 1. Introduction................................................................................................................. 1 2. Project description ...................................................................................................... 1 3. Experimental description ............................................................................................ 2 4. Methodology............................................................................................................... 4 4.1. Theory................................................................................................................. 4 4.2. Measurement apparatus ...................................................................................... 5 4.3. Data processing................................................................................................... 6 4.4. Acoustic metrics.................................................................................................. 7 4.4.1. Sound pressure levels.................................................................................