Home HomeLouis A. Challis, Challis and Associates Pty Ltd (Australia)
The Standards Committee, AV5 recently revised the presentation of an informative guideline for the assessment of environmental noise annoyance. This paper reviews the 25 years of statistical analyses from which the tabular percentile levels presented to the committee were derived.
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Marco Ciccozzi, South Australian Environmental Protection Authority (Australia)
Tony Circelli, South Australian Environmental Protection Authority (Australia)
Richard French, South Australian Environmental Protection Authority (Australia)
Australia is made up of a number of different states and territories. Each of these have their own governments which administer environmental noise policy. Historically there has been very little coordination or collaboration between the states to ensure a consistency of approach to such issues. For many years there was a group made up of environmental officers from most of the states that met on a regular basis. This group did achieve some good results in terms of rationalising research and the labelling of noisy equipment such as air conditioners, however it was disbanded just at the time when it was about to get stuck into the issues of uniformity between the states. As a result we have a situation where environmental noise is assessed in many different ways and by different agencies within each state or territory. Most states or territories are currently in the process of reviewing their noise policies. There has been much greater consultation between the states and territories during the development of their new policies than there ever was in the development of the original policies. Despite this however there will still be many significant differences between the policies when they have all been finished and become operational.
sv970557.pdf (Scanned) sv970557.pdf (From Postscript) TOPHans Olav K. Hygen, University of Bergen (Norway)
The experiment series, "Blast propagation through forest-Norwegian Trials" were carried out in a forest region at Finnskogen, Norway (N 50d 50', E 12d 00'). Sound pressure was generated by several explosions of 1, 8, 64kg C4 explosives, which were laid out on a two-axis system, 24km by 24km in a relatively flat forest terrain. The experiment consisted of one summer and one winter part, respectively. Thus, the effects of snow cover could be observed. The main purpose of these experiments was to gain more knowledge on the relationship between meteorology and sound propagation. Meteorological data were obtained by tethered balloons, radiosondes, automatic weather stations and turbulence measurements by eddy correlation method just above tree tops. This study uses the data from one morning where there was a strong temperature inversion. From the measurements of that day horizontal homogeneity of the atmosphere was verified. The difference of sound propagation in upwind and downwind conditions quantified to about 30dB transmission loss. Variation in recordings at single microphones during this morning was about 10dB, with 50dB transmission loss as an extreme value. The study ends with some attempts of modelling the sound propagation with a raytracings model and a FFP model.
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Byron Martin, VIPAC Engineers and Scientists (Australia)
Carl Q. Howard, University of Adelaide (Australia)
Acoustic measurements were taken at several existing entertainment venues to compare the noise levels with the draft guidelines suggested by the South Australian Environment Protection Authority. It is shown that the noise levels measured at the entertainment venues in the absence of music noise can exceed the criteria in the guidelines. The practicalities of the guidelines are discussed from a planning and design view point and also from a consultant's view point.
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Ian Donald McLeod, Monash University (Australia)
Charles G. Don, Monash University (Australia)
Impulsive sound is a revealing way of probing turbulent effects as changes to the pulse waveform represents the influence of the meteorological condition s over a short interval, When the wind speed is appropriately measured the propagation time can be accurately predicted, Even when a successful prediction of the pulse propagation time is achieved, efforts to quantitatively link changes in the pulse amplitude, waveform and spectrum to wind speed fluctuations have been largely unsuccessful, To be reported here are the results from a recent experiment in which four microphones, each accompanied by an anemometer, were placed 5m apart along the wind direction, The use of 5m spatial regimes allows a detail monitoring of the wind structure and the observation of progressive changes in the pulse waveform, Scattering between and from outside the line of microphones is investigated and the results are related to possible models of sound propagating in a turbulent field.
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Wai-Keung Wong, Environmental Protection Department (Hong Kong)
W.K. Szeto, Environmental Protection Department (Hong Kong)
Sam W.H. Wong, Environmental Protection Department (Hong Kong)
Noise from general construction activities in Hong Kong during restricted hours (between 7 p.m. and 7 a.m. on a weekday and at any time on a Sunday or public holiday) is controlled by means of a construction noise permit system. The contractor who wishes to carry out construction work in restricted hours has to ensure that the noise level so generated at noise sensitive receivers must be less than a set of Acceptable Noise Levels in order to obtain a permit from the Authority. Owing to the fast development in Hong Kong, complaints against construction noise are on the high side. The government has determined to further tighten up control of noise from general construction activities. As from 1.11.96, the Acceptable Noise Levels of five commonly used noisy equipment are lowered by 15 dB(A) and three type of prescribed construction work are virtually banned in high density built-up districts known as designated areas. This paper describes the tightened up new control and the parallel enforcement actions. The effects of the control on the construction industry are covered. To increase public awareness of their right on environmental quality and ensure compliance of the control by the industry, the Authority has provided publicity materials and established regular liaison meetings with the trade associations and private contractors.
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Lars Robert Hole, Norwegian Defence Construction Service (Norway)
Robert L. Guice, Applied Research Associates (U.S.A.)
This paper describes four sound propagation experiments which were undertaken in Norway from 1994 to 1996. Trials were carried out at Finnskogen; a long range site, and at Haslemoen; a short range site. Summer and winter conditions were investigated at both sites. Two similar experiments were carried out at each site with and without snow cover. At Finnskogen, an experimental array of 24 by 24 km was set up, in a terrain with smooth hills, primarily covered by forest. At Haslemoen, propagation was investigated out to 1.5 km above a uniform forest and a uniform, flat open field of pasture land. One, 8 and 64 kg cylindrical charges of C-4 explosives were used as sound sources. Measurements of acoustics, seismic ground response, complex ground impedance and meteorology were carried out simultaneously. This paper gives an overview of the experiments and presents examples of data. Literature for further details is referred. An easily accessible database with all data will soon be available. The database will be a valuable tool for development, validation, and refinement of sound propagation models. The structure of this database is outlined.
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Liberto Ercoli, Universidad Tecnologica Nacional (Argentina)
A.P. Azzurro, Universidad Tecnologica Nacional (Argentina)
M.T. Piovan, Universidad Tecnologica Nacional (Argentina)
A. Alvarez, Environment Direction, Municipality of Bahia Blanca (Argentina)
J. Smael, Environment Direction, Municipality of Bahia Blanca (Argentina)
Based on the public demand through noise complaints expressed by the neighbors to the local newspaper, radios and TV, a research project on community noise is being performed by the authors trying to find a practical methodology for the acoustic characterization of medium size cities (50,000 - 500,000 inhabitants). One of the research steps was to hold an environmental noise survey (more than 400 questionnaires were filled) in order to know the subjective opinion of the people about their neighborhood, main noise sources, level of annoyance, etc. Simultaneously, measurements were taken to objectively evaluate in- situ the actual noise levels. The present paper briefly shows preliminary resu lts on the correlation between the subjective opinions and objective measurements.
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