Executive Summaries (Sep 2016)

Executive Summaries of 2014 and 2015 Reports of National Academy of Engineers-Hosted Workshops

On February 19–20, 2014, the National Academy of Engineers (NAE) hosted a workshop called “Reducing Employee Noise Exposure in Manufacturing: Best Practices, Innovative Techniques, and the Workplace of the Future.” On October 6–7, 2015, the NAE hosted a workshop called “Engineering a Quieter America: Progress on Consumer and Industrial Product Noise Reduction.” The reports from these workshops (along with noted appendixes) can be found on the INCE-USA website athttp://www.inceusa.org/node/346. The executive summaries are provided below.

Executive Summary 2014

This report contains summaries of the papers presented at a workshop hosted by the National Academy of Engineering on February 19–20, 2014. The title of the workshop was “Reducing Employee Noise Exposure in Manufacturing: Best Practices, Innovative Techniques, and the Workplace of the Future.” Five major topics were addressed during the workshop:

  1. Hearing Conservation Programs in Manufacturing Industries
  2. Best Practices: Noise Control in Manufacturing Industries
  3. Engineering for Noise Control in Manufacturing
  4. Innovative Techniques for Engineering Noise Control
  5. The Manufacturing Workplace of the Future

The papers in this report have, in some cases, been ordered differently than at the workshop. The workshop agenda can be found in Appendix B of this report. Chapter 1 presents some general information on the scope and purpose of the workshop.

In Chapter 2, the workshop cochair, Lotz, first addressed the hearing conservation topic by presenting information on the programs of the National Institute for Occupational Safety and Health (NIOSH), in particular, the “Safe in Sound” award, which is given to companies with outstanding hearing conservation programs. Then Downey, Mulhausen, and Westrum described specific programs that have been implemented in their respective companies.

In Chapter 3, the topic “Best Practices: Noise Control in Manufacturing Industries” was addressed by five speakers. For new facilities, a key element of planning is the computer modeling of the workplace and the noise level of the equipment to be installed. Probst shows how the CADNA(R) program can be used to model the workplace once the dimensions of the space, the sound absorptive properties of the surfaces, and the noise emissions of the equipment to be installed are known. He gives several examples of successful modeling. Because of the importance of this topic, a long version of the work is presented in Appendix A, with a shorter version in the body of this report. The design of the equipment to go in the workplace is obviously an important factor for equipment manufacturers to consider. Herrin then presents information on the physics of low-noise product design. The next paper by Thompson includes information on the planning process used by NIOSH in the procurement of equipment in the mining industry where noise levels must be controlled. In the planning process, the user and the purchaser must know the noise emission levels of equipment to be installed, and emission standards facilitate the communications between buyer and seller. Murphy describes the key American National Standards for noise emissions. Finally, Maling describes “Buy Quiet” programs such as those developed by the National Aeronautics and Space Administration (NASA) and others. It is well accepted that the cost of noise control is lower during the machine design process than the cost of add-on solutions at the end of the design stage, or especially after the equipment has been delivered and installed. So the question has been asked: “Why buy a noise problem?”

The “best practices” topic continues in Chapter 4 with a series of papers on “Engineering for Noise Control in Manufacturing.” This has some overlap with the next chapter, Chapter 5, on “Innovative Techniques for Engineering Noise Control” because the engineering solutions described here may very well have been innovative at the time they were implemented. Chapter 4 contains an overview paper by Bruce on what progress has (and has not) been made in the reduction of noise in America’s manufacturing sector, and is followed by a series of papers devoted to specific engineering solutions for several sources. Wood discusses noise control for a manufacturing environment containing many sources. Stewart has two papers, the first devoted to a history of noise control in the textile, tobacco, and woodworking industries, and the second devoted to noise control of a shredding machine. Bruek discusses noise control at a metal conduit manufacturer, and Roberto and Tam cover several sources, including injector drills and vibratory feeders in a manufacturing plant.

“Innovative Techniques for Engineering Noise Control” is the title of Chapter 5. Lucas describes advanced aeroacoustic modeling techniques for the design of compressors, especially finite element techniques where the mesh “goes with the flow.” He continues with new techniques for pneumatic tools. Anderson has long experience in the automotive industry and describes manufacturing techniques in that industry. Barnes describes how a shift in process, from reciprocating equipment to rotary equipment, can lower noise levels. More describes techniques for the reduction of noise from power generator sets. Finally, Taylor describes an innovative method for removing rivets from airplanes using an electrodischarge machining method. The project is called Fastener Removal Improvement Technology Adoption (FRITA) and is said to result in a safer removal process with lower noise levels. In the final paper, Barnes describes a change from reciprocating to rotary equipment in a candy plant.

In Chapter 6, the authors give us a vision of the manufacturing workplace of the future. This topic was added to the workshop agenda because the National Academy of Engineering (NAE) initiated a broad study of future manufacturing, and the organizing committee felt that a glimpse of the future might give some direction to noise control engineering measures that might be needed in the future. Whitefoot presented an overview of the NAE program, Lilley gave a view from the National Institute for Standards and Technology (NIST), and Taylor gave her vision as seen by the National Center for Manufacturing Sciences (NCMS). In the final paper, Barnes describes what happens when sales and engineering personnel are on the factory floor.

Executive Summary 2015

This report documents two dozen noise control success stories during the past few decades. These were presented at a workshop attended by experienced engineers working for US manufacturers producing consumer products ranging from automobiles to yard-care leaf blowers, and industrial products ranging from air-moving devices to valves. Products ranged from small handheld devices to million-pound off-road trucks. The report addresses ongoing contributions by noise control engineers to improving both quality of life and the US economy by providing domestic manufacturers with the expertise to develop, produce, and sell the quieter products now demanded by global markets. Expected future noise control engineering technologies are also addressed.

The 2015 workshop was titled “Engineering a Quieter America: Progress on Consumer and Industrial Product Noise Reduction.” It was held on October 6–7, 2015, at the Keck Center of the National Academies in Washington, DC. Thirty-one people attended the workshop, and twenty-five technical presentations were made on a wide variety of associated topics. Adnan Akay, Eric Wood, Robert Hellweg, and George Maling served as cochairs of the workshop, and these four along with William Lang made up the organizing committee. NAE President Dan Mote and NAE Program Director Proctor Reid provided opening remarks.

Noise from consumer products was the subject of the first seven papers presented. Wayne Morris from the Association of Home Appliance Manufacturers (AHAM) said that the association has adopted a series of standards produced by the International Electrotechnical Commission (IEC) for the rating of home appliances. These standards, known as the IEC 60704 Series, cover a wide variety of home appliances and provide a consistent method of measuring the noise produced. When in use by all manufacturers, they will provide a uniform way for consumers to include consideration of noise emission when selecting products. Another organization that connects with the public is Consumer Reports (CR), which has collected a database of product noise levels that probably ranks among the largest in the world. CR’s Mark Connelly presented their test methods for rating noise.

The next presentations addressed how noise control engineering is applied to a wide variety of consumer products, from dishwashers to food waste disposers to leaf blowers to information technology equipment. Significant progress has been made over the last two decades in the production of quiet products, and consumer demand for quiet products is high. Matthew Nobile of Hudson Valley Acoustics presented a method of rating product noise that closely resembles IEC methods used in the appliance industry, and removes the confusion associated with noise emission ratings based on sound pressure and sound power.

One paper was presented on progress made in the reduction of automobile interior noise. Quiet automobile interiors are highly prized by consumers, and great progress has been made in identifying how noise enters the cabin and how it can be reduced.

The next presentations addressed the workshop’s second topic: commercial and industrial products. Robert Putnam discussed the need for quiet products in industry. Then, two presenters—representing the Air Heating and Refrigeration Institute and Ingersoll Rand, and the American Society of Heating, Refrigerating and Air-Conditioning Engineers—addressed the considerable progress made in the air-moving industry. Next, Geoff Sheard, the chair of the board of the Air Moving and Conditioning Association, discussed his industry’s progress including the use of computational techniques to design low-noise fan blades. Low-noise designs are needed as we move into the construction of high-performance buildings and green buildings. One finding in the “Technology for a Quieter America” report was that “There is wide dissatisfaction with noise in buildings in which business is conducted. Postoccupancy evaluations by the Center for the Built Environment at the University of California at Berkeley (2007) have shown that occupants are generally dissatisfied with noise and sound privacy.” Indications are that green buildings can be even worse.

Ten presentations were then devoted to progress in reducing noise from industrial products and components. Topics included:

  • Industrial power generation equipment
  • Electric power generator sets
  • Industrial motors
  • Compressors
  • Transformers
  • Valves and piping
  • Gears
  • Off-road machines
  • Mining equipment
  • Natural gas pipelines

Many of these products can be thought of as a system along the lines of the classic source-path-receiver model. But the current system model must include multiple sources, multiple paths, and in many cases, multiple receivers. Multiple sources include all of the components listed above.

Presenters consistently mentioned various drivers for noise control. While, in the context of consumer products, customer demand for quiet products and information on product noise is widespread, sources of demand for quiet commercial and industrial products include community requirements, community pressure, customer requirements, and government requirements.

There was little discussion about community requirements. Local noise ordinances are known to be inconsistent and in some cases out of date.

Community pressure can be felt in many ways. For example, a company installing power transformers may be aware of a surrounding community’s concerns about unacceptable noise, and may establish specifications that a transformer manufacturer must meet. Direct customer demand may arise when a builder of a system such as a power plant places noise requirements on the components that make up the system. Finally, there may be government requirements; examples are European noise requirements on construction equipment and, in the United States, FERC noise requirements on gas compressor stations and large LNG compressor facilities.

Two additional papers were presented. Kurt Yankaskas presented noise control work by the US Navy, and Robert Hellweg summarized national and international noise standards.