A metal spacecraft cabin ventilation fan suitable for aerodynamic and acoustic ground tests was designed and two copies of the fan assembly were fabricated. Both fans were tested for aerodynamic performance and acoustic levels in the NASA Glenn Research Center Acoustical Testing Laboratory. A new test rig for small axial flow fans was designed to accommodate the instrumentation and back-pressure adjustments. Measurements acquired were from: static pressures for measuring performance, a 72-channel in-duct microphone array, external microphone measurements for acoustics, and inter-stage hot wire measurements of the fan wake. This report documents the aerodynamic measurements as part of a series of reports.
{"title":"Quiet spacecraft cabin ventilation fan: aerodynamic measurements results","authors":"D. Stephens, Lisa Koch","doi":"10.3397/nc_2023_0017","DOIUrl":"https://doi.org/10.3397/nc_2023_0017","url":null,"abstract":"A metal spacecraft cabin ventilation fan suitable for aerodynamic and acoustic ground tests was designed and two copies of the fan assembly were fabricated. Both fans were tested for aerodynamic performance and acoustic levels in the NASA Glenn Research Center Acoustical Testing Laboratory.\u0000 A new test rig for small axial flow fans was designed to accommodate the instrumentation and back-pressure adjustments. Measurements acquired were from: static pressures for measuring performance, a 72-channel in-duct microphone array, external microphone measurements for acoustics, and inter-stage\u0000 hot wire measurements of the fan wake. This report documents the aerodynamic measurements as part of a series of reports.","PeriodicalId":19195,"journal":{"name":"Noise & Health","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89179864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACRP 175 was published in 2018 and provides basic guidelines for design, installation, and operation of public address systems in airport terminals. There are approximately 400 airports in the US, and with over 550 underground stations and 2,600 above ground stations in the US , many of these guidelines developed for airports can also be easily adapted for these transit stations. This paper provides an overview of ACRP 175 guidance with a focus on key factors for successful design and commissioning. As part of the research acoustic field studies were performed at six airports and a total of 45 different spaces including ticketing, concourse, gate lounges, food courts, arrival/departure halls, baggage claim, and curbside locations. We describe experience using ACRP 175 on current design-build projects and discuss other relevant industry standards.
{"title":"Improving Speech Intelligibility from PA Systems in Transportation Terminals","authors":"G. Glickman, Patrick Murphy, Deborah A. Jue","doi":"10.3397/nc_2023_0096","DOIUrl":"https://doi.org/10.3397/nc_2023_0096","url":null,"abstract":"ACRP 175 was published in 2018 and provides basic guidelines for design, installation, and operation of public address systems in airport terminals. There are approximately 400 airports in the US, and with over 550 underground stations and 2,600 above ground stations in the US , many\u0000 of these guidelines developed for airports can also be easily adapted for these transit stations. This paper provides an overview of ACRP 175 guidance with a focus on key factors for successful design and commissioning. As part of the research acoustic field studies were performed at six airports\u0000 and a total of 45 different spaces including ticketing, concourse, gate lounges, food courts, arrival/departure halls, baggage claim, and curbside locations. We describe experience using ACRP 175 on current design-build projects and discuss other relevant industry standards.","PeriodicalId":19195,"journal":{"name":"Noise & Health","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80133940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The exercise of validating a predictive model typically consists of modeling an existing real-world condition and predicting some resulting quantity of interest, and then comparing the predicted results to actual measured values for the same condition within a specified margin of error. In the case of road traffic noise models this would include modeling the characteristics of the existing roadway condition (geometry of the roadway network; number, vehicle type and speed of vehicles using the roadways; pavement types; intervening terrain; etc.) and comparing the resulting predicted noise level to actual noise measurements for the same conditions. In this paper the authors will provide a concise background of the validation purpose and process as well as a review of agency requirements and best practices for traffic noise model validation procedures.
{"title":"Requirements and best practices for traffic noise model validation","authors":"P. Burgé, G. Greer, M. Muirhead, Jessica Mahoney","doi":"10.3397/nc_2023_0086","DOIUrl":"https://doi.org/10.3397/nc_2023_0086","url":null,"abstract":"The exercise of validating a predictive model typically consists of modeling an existing real-world condition and predicting some resulting quantity of interest, and then comparing the predicted results to actual measured values for the same condition within a specified margin of error.\u0000 In the case of road traffic noise models this would include modeling the characteristics of the existing roadway condition (geometry of the roadway network; number, vehicle type and speed of vehicles using the roadways; pavement types; intervening terrain; etc.) and comparing the resulting\u0000 predicted noise level to actual noise measurements for the same conditions. In this paper the authors will provide a concise background of the validation purpose and process as well as a review of agency requirements and best practices for traffic noise model validation procedures.","PeriodicalId":19195,"journal":{"name":"Noise & Health","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72380453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The authors conducted investigations into noise from large rooftop air source heat pump (HP) equipment to student housing units below in a new concrete building. The investigation included both airborne noise and vibration measurements on the roof and in the dwelling units below. A total of five, 18-Ton devices were mounted on a foam-filled concrete housekeeping pad resting on an 8-inch thick PT structural slab and isolated by means of spring mounts fitted with neoprene isolation pads below their baseplate. The dwelling units below had exposed concrete at the ceiling, shear walls, and columns. Noise from the HPs were waking residents in the units directly below the equipment. After a number of adjustments to the spring isolation mounts to eliminate bindings and mechanical short-circuits, the investigation showed that vibration was also being transmitted to the building structure from the isolator base plates through the anchor bolts, bypassing the noise pads below the baseplate. Removal of this secondary short-circuit resulted in noticeable reductions in both noise and vibration at the spaces below, highlighting the need for careful adjustment and the provision of additional isolation elements in the installation.
{"title":"Case Study: Effect of mechanical short-circuiting of isolation pads on rooftop equipment noise and vibration transfer to spaces below.","authors":"Leisa Nalls, P. Daroux","doi":"10.3397/nc_2023_0033","DOIUrl":"https://doi.org/10.3397/nc_2023_0033","url":null,"abstract":"The authors conducted investigations into noise from large rooftop air source heat pump (HP) equipment to student housing units below in a new concrete building. The investigation included both airborne noise and vibration measurements on the roof and in the dwelling units below. A\u0000 total of five, 18-Ton devices were mounted on a foam-filled concrete housekeeping pad resting on an 8-inch thick PT structural slab and isolated by means of spring mounts fitted with neoprene isolation pads below their baseplate. The dwelling units below had exposed concrete at the ceiling,\u0000 shear walls, and columns. Noise from the HPs were waking residents in the units directly below the equipment. After a number of adjustments to the spring isolation mounts to eliminate bindings and mechanical short-circuits, the investigation showed that vibration was also being transmitted\u0000 to the building structure from the isolator base plates through the anchor bolts, bypassing the noise pads below the baseplate. Removal of this secondary short-circuit resulted in noticeable reductions in both noise and vibration at the spaces below, highlighting the need for careful adjustment\u0000 and the provision of additional isolation elements in the installation.","PeriodicalId":19195,"journal":{"name":"Noise & Health","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89939273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solid safety barriers are commonly constructed along highways. These barriers improve highway safety by preventing collisions and providing separation from slopes or adjacent hazards such as deep water. For elevated and at-grade roadways, shorter barriers have also been shown to noticeably reduce traffic noise. In prior research, modeling methods were developed and evaluated for their ability to accurately calculate the performance of short barriers in reducing traffic noise at the wayside. The modeling results were compared to available field data and to the results of FHWA's Traffic Noise Model version 2.5 (TNM). This paper extends the prior research to compare the results to the newest FHWA TNM version, 3.1.
{"title":"Noise modeling of short safety barriers in FHWA's updated Traffic Noise Model (TNM) version 3.1","authors":"Dana M. Lodico","doi":"10.3397/nc_2023_0021","DOIUrl":"https://doi.org/10.3397/nc_2023_0021","url":null,"abstract":"Solid safety barriers are commonly constructed along highways. These barriers improve highway safety by preventing collisions and providing separation from slopes or adjacent hazards such as deep water. For elevated and at-grade roadways, shorter barriers have also been shown to noticeably\u0000 reduce traffic noise. In prior research, modeling methods were developed and evaluated for their ability to accurately calculate the performance of short barriers in reducing traffic noise at the wayside. The modeling results were compared to available field data and to the results of FHWA's\u0000 Traffic Noise Model version 2.5 (TNM). This paper extends the prior research to compare the results to the newest FHWA TNM version, 3.1.","PeriodicalId":19195,"journal":{"name":"Noise & Health","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82496698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This case study highlights a successful project for a grocery store that required exhaust fan outdoor noise control due to a complaint from a residential condominium building across the street. Sound pressure level measurement results are provided for exhaust fan operating conditions for both before and after the installation of noise mitigation solutions.
{"title":"Case Study: Grocery Exhaust Fan Environmental Noise Mitigation","authors":"Josh Thede","doi":"10.3397/nc_2023_0056","DOIUrl":"https://doi.org/10.3397/nc_2023_0056","url":null,"abstract":"This case study highlights a successful project for a grocery store that required exhaust fan outdoor noise control due to a complaint from a residential condominium building across the street. Sound pressure level measurement results are provided for exhaust fan operating conditions\u0000 for both before and after the installation of noise mitigation solutions.","PeriodicalId":19195,"journal":{"name":"Noise & Health","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75417439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Conference rooms are acoustically sensitive environments due to the need for high speech intelligibility both in-person and over teleconferencing systems. Room noise from building systems is a key contributing factor to speech intelligibility. Mechanical design, and in turn noise control design, focuses on peak heating and cooling demand; however, operating conditions vary based on the demand at any given time. This case study presents sound pressure level measurements from a conference room on the top floor of an office building, which was below a mechanical penthouse. The measurements were guided by ANSI/ASA S12.2, "Criteria for Evaluating Room Noise." Commissioning and developer agents varied the operating conditions of the entire building heating and cooling system to identify the primary contributors to room noise levels in the conference room, which varied as much as 13 dBA over background. Particular attention is given to the correlation between room noise levels and airflow from the air terminal unit serving the space. Comparisons between measured noise levels and noise modeling predictions are also provided.
{"title":"Case study of HVAC noise in a conference room under varying operating conditions","authors":"Adam T. Buck","doi":"10.3397/nc_2023_0084","DOIUrl":"https://doi.org/10.3397/nc_2023_0084","url":null,"abstract":"Conference rooms are acoustically sensitive environments due to the need for high speech intelligibility both in-person and over teleconferencing systems. Room noise from building systems is a key contributing factor to speech intelligibility. Mechanical design, and in turn noise control\u0000 design, focuses on peak heating and cooling demand; however, operating conditions vary based on the demand at any given time. This case study presents sound pressure level measurements from a conference room on the top floor of an office building, which was below a mechanical penthouse. The\u0000 measurements were guided by ANSI/ASA S12.2, \"Criteria for Evaluating Room Noise.\" Commissioning and developer agents varied the operating conditions of the entire building heating and cooling system to identify the primary contributors to room noise levels in the conference room,\u0000 which varied as much as 13 dBA over background. Particular attention is given to the correlation between room noise levels and airflow from the air terminal unit serving the space. Comparisons between measured noise levels and noise modeling predictions are also provided.","PeriodicalId":19195,"journal":{"name":"Noise & Health","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76205701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In today's automotive industry, sound package design and optimization is important considering the mounting need for weight reduction and achieving targeted sound absorption and sound transmission loss values. The present paper relates to dual layered light weight (LW) fire resistant (FR) Polyurethane (PU) foam-based composite for engine room insulation, referred herein as Ωµ2 foam comprising of two layers of foam having different densities and flexibility. The composite consists of one layer of semirigid FR PU foam acting as a carrier with sound absorptive property and another layer consisting of flexible FR PU foam acting as higher acoustical absorptive property. This concept is intended for enhancement of acoustical performance by the synergistic effect of dual foam layers besides being FR and LW material, specially designed for passenger vehicles' engine compartment insulations such as firewall/dash panel, bonnet/hood liner insulation and other diverse applications in commercial vehicles. The paper presents material properties and in-depth comparative assessment of sound absorption properties of dual layer (Ωµ2) LW FR PU foam with respect to conventional materials like single layer light weight semi-rigid PU foam and resinated cotton shoddy felt, etc.
{"title":"Dual layered light weight fire resistant PU foam-based composite for acoustical insulation","authors":"Navin Banka, Debasish Chatterjee","doi":"10.3397/nc_2023_0132","DOIUrl":"https://doi.org/10.3397/nc_2023_0132","url":null,"abstract":"In today's automotive industry, sound package design and optimization is important considering the mounting need for weight reduction and achieving targeted sound absorption and sound transmission loss values. The present paper relates to dual layered light weight (LW) fire resistant\u0000 (FR) Polyurethane (PU) foam-based composite for engine room insulation, referred herein as Ωµ2 foam comprising of two layers of foam having different densities and flexibility. The composite consists of one layer of semirigid FR PU foam acting as a carrier with sound absorptive property\u0000 and another layer consisting of flexible FR PU foam acting as higher acoustical absorptive property. This concept is intended for enhancement of acoustical performance by the synergistic effect of dual foam layers besides being FR and LW material, specially designed for passenger vehicles'\u0000 engine compartment insulations such as firewall/dash panel, bonnet/hood liner insulation and other diverse applications in commercial vehicles. The paper presents material properties and in-depth comparative assessment of sound absorption properties of dual layer (Ωµ2) LW FR PU foam\u0000 with respect to conventional materials like single layer light weight semi-rigid PU foam and resinated cotton shoddy felt, etc.","PeriodicalId":19195,"journal":{"name":"Noise & Health","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72479385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Profiled composite floors (ribbed concrete slabs on corrugated steel decks) are commonly used in steel framed buildings. However, complicating the dynamic modeling of such floors is their apparent stiffness anisotropy due to the periodically spaced ribs. In this paper, approaches are presented to obtain the effective, flat-plate properties of composite floors to predict floor vibrations for two building case studies. Measured floor vibrations for the case studies are then compared to the models.
{"title":"Vibration modeling of buildings with composite floors","authors":"Christopher Layman, G. Glickman, Silas Bensing","doi":"10.3397/nc_2023_0107","DOIUrl":"https://doi.org/10.3397/nc_2023_0107","url":null,"abstract":"Profiled composite floors (ribbed concrete slabs on corrugated steel decks) are commonly used in steel framed buildings. However, complicating the dynamic modeling of such floors is their apparent stiffness anisotropy due to the periodically spaced ribs. In this paper, approaches are\u0000 presented to obtain the effective, flat-plate properties of composite floors to predict floor vibrations for two building case studies. Measured floor vibrations for the case studies are then compared to the models.","PeriodicalId":19195,"journal":{"name":"Noise & Health","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75721956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As acoustical engineers, we are often asked to develop community noise-related guidelines, regulations, laws, ordinances, and project specifications. This paper will describe the ingredients needed to develop a robust and defensible construction noise specification that is both enforceable and effective. It will be based on the author's past and current experiences developing such specifications, including those used for the Big Dig project in Boston, FHWA's construction noise handbook, the New York City construction noise regulation, as well as dozens of large-scale construction projects across the country. The goals of proactive and reactive noise control and the difference between a performance-based versus a prescriptive-based specification will be explained, community noise criteria will be suggested, and examples will be provided for important clauses in such a specification. Lastly, a listing of "lessons learned" over the decades will be provided.
{"title":"Developing a Comprehensive Construction Noise Specification","authors":"E. Thalheimer","doi":"10.3397/nc_2023_0003","DOIUrl":"https://doi.org/10.3397/nc_2023_0003","url":null,"abstract":"As acoustical engineers, we are often asked to develop community noise-related guidelines, regulations, laws, ordinances, and project specifications. This paper will describe the ingredients needed to develop a robust and defensible construction noise specification that is both enforceable\u0000 and effective. It will be based on the author's past and current experiences developing such specifications, including those used for the Big Dig project in Boston, FHWA's construction noise handbook, the New York City construction noise regulation, as well as dozens of large-scale construction\u0000 projects across the country. The goals of proactive and reactive noise control and the difference between a performance-based versus a prescriptive-based specification will be explained, community noise criteria will be suggested, and examples will be provided for important clauses in such\u0000 a specification. Lastly, a listing of \"lessons learned\" over the decades will be provided.","PeriodicalId":19195,"journal":{"name":"Noise & Health","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77813548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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