ACRP-Problem-No-10-02-24.pdf
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1、ACRP Problem No. 10-02-24 Recommended: No Development of a database of case studies that would help in formulation of guidelines for predicting and mitigating low frequency noise problems around airports. ACRP Staff The scope of this problem statement appears to be complimentary to other ACRP resear
2、ch on noise but should be closely coordinated to avoid overlap. TRB Aviation Group Environmental Impacts of Aviation Cmte: FAA is currently developing guidelines for addressing low frequency noise (LFN) around airports. Much of the information proposed in this project already is available. Do not fu
3、nd. Panel for Environmental Emphasis The scope is too limited and is not a priority for ACRP research. AIRPORT COOPERATIVE RESEARCH PROGRAM PROBLEM STATEMENT A AC CR RP P Problem Number Problem Number 10-02-24 I. PROBLEM TITLE Development of a database of case studies that would help in formulation
4、of guidelines for predicting and mitigating low frequency noise problems around airports. II. RESEARCH PROBLEM STATEMENT Low frequency noise from aircraft operations near airports is a problem that does not appear to be well predicted by day-night level (DNL) or other A-weighted based metrics. House
5、 construction, orientation of house to airport runways, window characteristics, and interior furnishings all impact what is sensed within the home, thus people with the same outdoor noise exposure may experience very different indoor conditions. Wind conditions may also affect the situation making i
6、t difficult to perform repeatable measurements and also to observe the same effects that occupants report when taking a limited set of measurements. The are three main issues with low frequency noise are: (1) rattle may occur, (2) people may sense vibration, (3) if neither vibration nor rattle occur
7、, how should the low frequency sound be measured to reflect its impact on occupants? There are various methodologies and proposed metrics for predicting whether a potential problem may occur but there is not general agreement on the utility of these methods. The variety of parameters that can affect
8、 the environment inside the house perhaps make it difficult to draw general conclusions about low frequency noise problems. This is extremely problematic, because airport managers need to be able to predict whether people are likely to experience any or all of the problems mentioned above and to und
9、erstand how these problems can be mitigated effectively. To make matters worse ratings of windows are based on a metric that does not include sound transmission at low frequencies ( 125 Hz) which is dominated by resonant behavior of window panes. This is a complicated problem, and people need guidel
10、ines to help them identify if the problem causing concern is truly a low frequency noise problem and if a particular noise mitigation approach is likely to be successful. Noise prediction programs are gradually being improved incorporating more accurate models of low frequency aircraft noise source
11、and propagation characteristics. Relatively sophisticated models of sound transmission can be constructed by using advanced computational methods to predict indoor noise levels. Our ability to predict rattle is somewhat limited, but there are some models that can be used to predict likelihood of rat
12、tle for different situations given levels and frequency content of the noise. Improvements in all of these aspects of low frequency sound and physical consequences is the subject of ongoing research. Developers of these tools need good data to be able to validate their predictions. So there are two
13、groups that need information on these low frequency noise problems near airports: (1) the local airport that needs to be able to assess the likelihood of low frequency noise problems occurring and which mitigation strategies to recommend, and (2) the researchers who are developing the prediction sof
14、tware that will enable the local airport to make more informed decision on low frequency noise problems. These researchers need data from realistic situations to ensure that their programs are indeed accurate and helpful. Unfortunately, in the short term, the airports cannot wait for the researchers
15、 to produce the perfect code. It is argued here that what both of these groups could benefit from is access to data from a number of low frequency investigations around airports. That is, for a number of cases, access to: II.a measurements of indoor and outdoor noise sounds and vibration; II.b resul
16、ts of analysis, e.g., spectra, single number metrics, etc. II.c detailed descriptions of the house construction, orientation, usage and furnishings; II.d detailed descriptions of the problem as articulated by the occupant; II.e detailed descriptions of the problem as articulated by the consultant wo
17、rking on the problem, and the probable causes of the problem; II.f the mitigation strategy recommended and rationale for it; II.g the effectiveness of the mitigation, if done, as assessed by the occupant; II.h the effectiveness of the mitigation, if done, as assessed by the consultant. It is also ar
18、gued that if there are a sufficient number of case studies, there will be a level of understanding gained by studying this set of case histories (strategies that worked, typical cause- effect scenarios, etc.) that will be useful to airport operators. Making the data available to the research communi
19、ty will also enable validation of the computational tools that will be the planning tools of the future. III. OBJECTIVES To put together the data from a set of representative, previously conducted, case studies involving low frequency noise problems around airports to help airport operators gain ins
20、ight into the causes of these problems and learn which mitigation strategies have been most effective. To provide researchers the data necessary to validate and improve prediction of low frequency noise in houses around airports as well as other outcomes such as vibration and rattle. IV. RESEARCH PR
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