Download PDF Summer Bridge on Noise Control Engineering June 15, 2021 Volume 51 Issue 2 What is the role of engineering practice, education, and standards in mitigating human-generated noise? The articles in this issue survey these aspects of the US noise landscape, and offer updates and useful resources. A Decade and a Half of Progress Toward Reducing Noise in the United States Wednesday, June 16, 2021 Author: Eric W. Wood and George C. Maling Jr. The NAE and INCE Foundation have engaged the noise control engineering community to advance efforts to improve noise in the United States. The year 2020 marks 15 years since kick-off of the Technology for a Quieter America (TQA) project (figure 1), a joint effort of the National Academy of Engineering (NAE) and the INCE Foundation to look at noise in the United States, including its sources, how it is characterized, and efforts to reduce it. The TQA project grew from one visionary noise control engineer’s idea for a consensus study, and led to the landmark Technology for a Quieter America report (NAE 2010) as well as follow-up workshops on specific related subject areas. Background It was the late William (Bill) W. Lang (NAE; 1926–2016)—physicist, distinguished noise control expert, and cofounder of INCE-USA and the INCE Foundation—who in 2005 conceived and proposed a joint project with the NAE to study noise in this country. NAE president Wm. A. Wulf approved the project, with the understanding that Bill would identify funding. While the vision was initially limited to a consensus study, a series of follow-on workshops have continued to gather expert perspectives in various related areas. In preparation for the consensus study, a scoping workshop was held in Washington in October 2005. Then a series of workshops (2007–09) reviewed the state of technology in noise control engineering and considered how existing and future technologies could help reduce noise exposure in the United States. After publication of the 2010 TQA report, in 2011 the National Park Service (NPS) asked the NAE “to assist the NPS in refining portions of its national noise program,” accounting for the importance of quiet for both visitors and wildlife in the hundreds of NPS properties. The NAE convened park personnel and noise control specialists who, in themed workshop breakout groups, identified 17 cost-effective actions to assist park managers in controlling and reducing noise associated with transportation, maintenance, and construction in US national parks (NAE 2013). TQA Follow-on Workshops Since 2012 a series of follow-on workshops have convened experts to expand on selected topics covered in the TQA report, toward improving the noise climate in the United States. The workshops were led and financially supported by Bill Lang through the INCE Foundation, and (unless otherwise indicated in the following accounts) hosted by the NAE in its Washington facilities. NAE support was provided by the Michiko So Finegold Memorial Trust. Reports of the workshops are freely accessible as PDFs on the INCE-USA website. Noisy Motorcycles: An Environmental Quality-of-Life Issue In 1980 the EPA implemented a federal regulation to limit noise from motorcycles. But although motorcycles today come from the manufacturer with well-designed and effective exhaust systems, noise problems occur when a consumer replaces the original exhaust system with noncompliant components. Some bikers believe loudness confers safety, others just want loud bikes. In the first follow-on workshop, held in October 2012 and sponsored by the INCE Foundation and Noise Control Foundation, 29 experts representing motorcycle manufacturers, rider organizations, government agencies, universities, noise control consultants, and the public explored ways to address problems associated with noisy motorcycles. These included federal motorcycle noise regulations that do not reflect current motorcycle design technology or operator use patterns and that preclude effective enforcement of motorcycle noise by state and local authorities. The workshop report includes 30 recommendations for addressing these and other types of issues (INCE-USA 2013). For example, in an effort to assist state and local governments that want to reduce motorcycle noise, the report recommends that “States concerned with motorcycle noise should look to state and local governments, such as Golden, Colorado, and New Hampshire, to develop education-based programs to encourage riders to keep noise low. Find a way for states to share information on their motorcycle noise programs” (p. 54). Cost-Benefit Analysis: Noise Barriers and Quieter Pavements It is well recognized that highway noise is a quality-of-life issue. More than $5 billion has been spent constructing more than 3000 linear miles of roadside noise barriers in the United States. The main source of noise emissions from highways is the interaction between vehicle tires and the road surface. Considerable research and development has shown that changing the design of the road surface can reduce noise emissions. A workshop in January 2014 addressed the costs and benefits of highway noise barriers, lower-noise road surfaces, and combinations of the two. Ten findings and recommendations are provided in the workshop report, based on presentations by 23 experts. One recommendation was “Encourage [the Federal Highway Administration] to develop guidance on the use of quieter pavements and barriers for noise abatement” (INCE-USA 2014, p. 2). The workshop was sponsored by the INCE Foundation, the Noise Control Foundation, and the Transportation Research Board Committee on Transportation-Related Noise and Vibration, and organized in cooperation with the US Department of Transportation Volpe Center. Reducing Employee Noise Exposure in Manufacturing: Best Practices, Innovative Techniques, and the Workplace of the Future At this February 2014 workshop more than 20 experts discussed conservation programs in manufacturing industries, best practices and innovative techniques for engineering noise control in this context, and a vision for the manufacturing workplace of the future. Presentations and discussions considered (i) the availability of effective low-cost techniques for the reduction of noise in industry and the design of low-noise machines for industrial use, (ii) techniques for reducing noise through changes in processes in industrial plants, and (iii) the future manufacturing environment and implications for new noise goals in manufacturing facilities (INCE-USA 2016a). The workshop was sponsored and organized by the INCE Foundation, Noise Control Foundation, and National Institute for Occupational Safety and Health. Engineering a Quieter America: Progress on Consumer and Industrial Product Noise Reduction Contributions of noise control engineers have improved quality of life and the US economy by providing domestic manufacturers with the expertise to develop, produce, and sell quieter products that are desired or required nationally and globally. This workshop, in October 2015, reviewed progress in addressing noise associated with both consumer products (from automobiles to waste disposal systems to leaf blowers) and industrial products (from air-moving devices to valves), in both categories ranging in size from small handheld devices to million-pound off-road trucks. Anticipated future noise control engineering technologies were also discussed. Speakers represented manufacturers, consultants, trade and standards associations, universities, and a well-known consumer publication. Many of the 31 attendees had 30 to 40 years of direct engineering experience in consumer at-home products or industrial products. The event was organized by the INCE Foundation and Noise Control Foundation. Noise control engineers improve quality of life and the US economy by providing the expertise to develop, produce, and sell quieter products. Among the observations conveyed in the workshop report, “Product manufacturers have determined that ‘quiet’ pays as does ‘sound quality.’ Lower sound levels and enhanced sound quality both help to differentiate their products. They provide additional brand recognition. They also increase sales and help the bottom line. And it has been found that in the course of designing a product to decrease noise, sometimes performance is also bolstered” (INCE-USA 2016b, p. 145). Engineering Technology Transfer: Research and Development for Engineering a Quieter America Looking at current research by government, universities, and the private sector, this workshop considered which research holds promise for translation into useful, innovative noise control solutions and, ultimately, for enhancing the ability of engineers to solve problems and improve US industry competitiveness. The workshop, held in October 2016, was attended by 32 experts and organized by the INCE and Noise Control Foundations. The report’s summary of panel discussions noted, for instance, the observation of the panel on advanced methods for noise control engineering that “It is likely that development of advanced methods in noise control engineering will be computer-based (involving, for example, computational fluid dynamics, source localization, path noise control, and instrumentation). The panel’s focus is on future developments in computer-supported techniques” (INCE-USA 2017a, p. 104). Commercial Aviation: A New Era While significant progress has been made in reducing noise from commercial aircraft, additional government support in aeronautics is needed. The United States is a world leader in aviation technology. A principal focus of this workshop included step-changes in the technology of future aircraft necessary for the country to maintain both its global leadership position and the very positive trade balance that aviation brings to the US economy. This workshop in May 2017 was organized by the INCE Foundation and conducted in cooperation with NASA and the FAA. It was attended by more than 60 experts representing airplane and engine manufacturers, aircraft research organizations, airlines and cargo operators, airports, universities, NASA, the FAA, consultants, and interested communities. The vital importance of government funding required to continue X-system development in flight testing was emphasized by presenters. They also made the case that, while significant progress has been made in reducing noise from commercial aircraft, additional government support in aeronautics is needed to maintain US global leadership. This is particularly true given the immense government support provided in other countries—notably, in the European Union and China. A panel discussion on a low-noise future considered many alternatives. “Options must be kept on the table…[whether] related to the open rotor or other technology—toward achieving sought-after changes in acoustics, emissions, and energy” (INCE-USA 2017b, p. 119). UAS and UAV (Drone) Noise Emissions and Noise Control Engineering Technology This December 2018 workshop, organized by the INCE Foundation in cooperation with NASA and the FAA, focused on unmanned aerial systems/vehicles (UAS/UAVs), or drones. UAVs are expected to become a common part of US national airspace within the next few decades. At the workshop, experts from government, academia, and the private sector addressed future uses, noise emissions, and noise control technologies. At the conclusion of the workshop, one participant remarked “What’s next? Where do we go from here?” (INCE-USA 2020a, p. 165). Coordination among primary actors such as NATO, NASA, the FAA, and industry would be useful. And to collaborate in terms of filling data gaps, NASA might serve as a repository for UAV/UAS data for researchers as they develop models. Noise Control Engineering Education: Session at NOISE-CON 2019 A session at the NOISE-CON 2019 conference held in August in San Diego was a follow-on to the recommendations in the 2010 TQA report chapter 9, “Education Supply and Industry Demand for Noise Control Specialists” (NAE 2010, p. 129): Recommendation 9-1: Academic institutions should offer an undergraduate course in noise control engineering, broaden the scope of the engineering curriculum, and increase the pool of engineering graduates equipped to design for low noise emissions. The course could be offered as an elective in a bachelor’s degree program or as part of a minor (e.g., in acoustics or interdisciplinary studies). Recommendation 9-2: Graduate-level noise control courses should provide a balance between theory and engineering practice, without sacrificing academic rigor. The committee strongly encourages the establishment of graduate internships in industry and government agencies and thesis research programs to motivate students and build a cadre of future noise control engineers. Recommendation 9-3: Federal agencies, private companies, and foundations with a stake in noise control should provide financial support for graduate students assisting with noise control engineering research or teaching. This support is crucial for the development of noise control professionals and noise control educators. This session featured nine presentations by academics, consultants, and industry representatives about sources for noise control engineering education, including undergraduate and graduate courses as well as short courses available to practicing engineers. A key question during the session was “Does demand for graduates in noise control engineering exceed supply?” The consensus: It does. Academic institutions receive many requests for noise control engineering graduates. And during the session, a participant followed up on a point made by presenters that graduate students land employment easily in noise control engineering: How can that demand be driven home to university administrators and funding sources to address the supply side of this equation? Noise Control Engineering Education This December 2019 workshop, attended by 28 experts, explored ways to broaden opportunities for noise control engineering education, covering the perspectives of universities, industry, government, and professional societies. Presentations addressed graduate and undergraduate educational offerings, including traditional and distance learning; continuing education courses, including short courses; educational opportunities sponsored by government agencies; and informal learning opportunities such as mentorships and involvement in professional society activities. Noise control engineering integrates elements of electrical engineering, architectural acoustics, psychoacoustics, physiological acoustics, and a number of other subjects. Unlike traditional engineering fields, it does not have its own dedicated department at American universities. Instead, the curriculum is included in other departments, usually mechanical or aerospace engineering. Workshop presenters also considered coverage of noise control in universities’ architectural programs, psychological acoustics, and the role of engineering in K–12 education. As was discussed at the NOISE-CON session, this workshop drove home the importance of noise control engineering education in light of the very high demand for graduates in the field, which according to the consensus of the presenters far exceeds the supply. Recommendations were developed at the end of the workshop, related to three general themes (INCE-USA 2020b, p. 113): Encourage an enhanced presence of noise control and related topics in existing curricula, including undergraduate and community college programs. Develop and promote noise control and acoustics resources, both basic and more in-depth. Attract interest to noise control by promoting the field, with efforts to do so through a modern lens. Aerial Mobility: Noise Issues and Technology This virtual workshop, held in December 2020, was organized by the INCE Foundation in cooperation with NASA and FAA as a follow-on to both the 2018 workshop on UAS/UAV noise (INCE-USA 2020a) and a recent report, Advancing Aerial Mobility: A National Blueprint (NASEM 2020). Unlike traditional engineering fields, noise control engineering does not have its own dedicated department at US universities. Aerial mobility (the preferred term in the aviation community) includes urban air mobility (UAM), cargo vehicles, and drones. Noise from these vehicles is a focus area for both the FAA and NASA. The 2020 NASEM report (p. 5) stated that “Public acceptance of advanced aerial mobility, particularly noise aspects and its psychological factors, is perhaps one of the biggest challenges along with safety. Failure to address these issues could hinder advanced aerial mobility implementation.” Improved understanding of these sources and effects on communities is needed to assist government, industry, and academia in formulating plans to advance noise control technology for aerial vehicles. The following topics were discussed at the workshop: a report on the 2020 Quiet Drone symposium in Paris NATO-sponsored progress on rotor and propeller noise technology for the design of aerial mobility vehicles (AMVs) operational strategies to reduce the noise emitted by AMVs uses of AMVs in the private sector, with emphasis on the importance of noise measurement methods and metrics for determination of noise from AMVs noise standards and harmonization with national and international bodies community response to noise from AMVs coordination of federal requirements and state and local regulations. Publication of the report of this virtual workshop is expected later in 2021. Conclusion The 10 workshops summarized above and the corresponding reports are a strong beginning to the ongoing series on important topics in noise control engineering. The TQA report itself was a broad-brush treatment of noise control in the United States, so there are other topics to be covered. For example, a workshop scheduled for October 19–20, 2021, will look at new technologies for noise control, and plans are being made for an event in 2022. Acknowledgments The cooperation of the FAA, NASA, and NIOSH in the organization of several workshops contributed greatly to the resulting reports. Tamar Nordenberg (Vie Communications) was the rapporteur and key writer of most of the INCE-USA workshop reports. The members of the steering committee for almost all the workshops were Adnan Akay (Bilkent University), Gregg Fleming (US DOT/Volpe Center), Robert Hellweg (Hellweg Acoustics), and both of us. None of this work would have been possible without William W. Lang’s vision and generous funding. References INCE-USA [Institute of Noise Control Engineering of the USA]. 2013. Noisy Motorcycles—An Environmental Quality-of-Life Issue. Reston VA. INCE-USA. 2014. Cost-Benefit Analysis: Noise Barriers and Quieter Pavements. Reston VA. INCE-USA. 2016a. Reducing Employee Noise Exposure in Manufacturing: Best Practices, Innovative Techniques, and the Workplace of the Future. Reston VA. INCE-USA. 2016b. Engineering a Quieter America: Progress on Consumer and Industrial Product Noise Reduction. Reston VA. INCE-USA. 2017a. Engineering Technology Transfer: Research and Development for Engineering a Quieter America. Reston VA. INCE-USA. 2017b. Engineering a Quieter America: Commercial Aviation: A New Era. Reston VA. INCE-USA. 2020a. Engineering a Quieter America: UAS and UAV (Drone) Noise Emissions and Noise Control Engineering Technology. Reston VA. INCE-USA. 2020b. Engineering a Quieter America: Noise Control Engineering Education. Reston VA. NAE [National Academy of Engineering]. 2010. Technology for a Quieter America. Washington: National Academies Press. NAE. 2013. Protecting National Park Soundscapes: Summary of a Workshop. Washington: National Academies Press. NASEM [National Academies of Sciences, Engineering, and Medicine]. 2020. Advancing Aerial Mobility: A National Blueprint. Washington: National Academies Press.  The foundation was established in 1993 by the Institute of Noise Control Engineering of the USA (INCE-USA).  Until 2016 the workshops were organized on an ad hoc basis with approval from the NAE Program Office; after that, member-initiated events were covered under NAE policy.  www.inceusa.org/publications/technology-for-a-quieter- america. These summaries compliment articles published in Noise Control Engineering Journal and Noise/News International, and presented at INTER-NOISE and NOISE-CON conferences. About the Author:Eric Wood is cofounder and principal of Acentech Incorporated. George Maling (NAE) is managing director emeritus of INCE-USA.