Noise mitigation is a set of strategies to reduce unwanted environmental sound. The main topics of noise mitigation (alternatively known as noise abatement) are: transportation noise control, architectural design, and occupational noise control. Roadway noise and aircraft noise are the most pervasive sources of environmental noise worldwide, and remarkably little change has been effected in source control in these areas since invention of the original vehicles. The sole exception to have widespread potential impact is development of the hybrid vehicle. This article or section does not adequately cite its references or sources. ... Traditionally, workplace noise has been a hazard linked to heavy industries such as ship-building and associated only with noise induced hearing loss (NIHL). ... Roadway noise is the most prevalent form of environmental noise. ... Aircraft noise is defined as sound produced by any aircraft on run-up, taxiing, take off, over flying or landing. ... Noise pollution, usually called environmental noise in technical venues, is displeasing human or machine created sound that disrupts the environment. ... A hybrid vehicle (HV) is a vehicle that uses two or more distinct power sources such as: An on-board rechargeable energy storage system (RESS) and a fueled power source for vehicle propulsion Human powered bicycle with battery assist A sail boat with electric power[1] The term most commonly...

A panoply of techniques have been developed to address interior sound levels, many of which are encouraged by local building codes; in the best case of project designs, planners are encouraged to work with design engineers to examine tradeoffs of roadway design and architectural design. These techniques include design of exterior walls, party walls and floor/ceiling assemblies; moreover, there are a host of specialized means for dampening reverberation from special purpose rooms such as auditoria, concert halls, dining areas and meeting rooms. Many of these techniques rely upon materials science applications of constructing sound baffles or using sound absorbing liners for interior spaces. Industrial noise control is really a subset of interior architectural control of noise, with emphasis upon specific methods of sound isolation from industrial machinery and for protection of workers at their task stations. A building code is a set of rules that specify the minimum acceptable level of safety for constructed objects such as buildings and nonbuilding structures. ... An auditorium is the area within a theatre, concert hall or other performance space where the audience is located in order to hear and watch the performance. ... A Concert hall is a cultural building, which serves as performance venue, chiefly for classical instrumental music. ... A sound baffle is a construction or device which reduces the intensity of airborne sound. ...

Roadway noise mitigation

This Hybrid vehicle can operate 15 to 25 decibels more quietly than conventional autos at speeds less than 60 km/h

Source control in roadway noise has provided little reduction in vehicle noise, except for the development of the hybrid vehicle; nevertheless, hybrid use will need to attain a market share of roughly fifty percent to have a major impact on noise source reduction on city streets. (Highway noise is little affected by automobile type, since those effects are aerodynamic and tyre noise related.) Other contributions to reduction of noise at the source are: improved tire tread designs for trucks in the 1970s, better shielding of diesel stacks in the 1980s, and local vehicle regulation of unmuffled vehicles. Image File history File linksMetadata Size of this preview: 800 × 535 pixel Image in higher resolution (2636 × 1764 pixel, file size: 822 KB, MIME type: image/jpeg) I took this photo and i release all rights I, the creator of this work, hereby release it into the public domain. ... Image File history File linksMetadata Size of this preview: 800 × 535 pixel Image in higher resolution (2636 × 1764 pixel, file size: 822 KB, MIME type: image/jpeg) I took this photo and i release all rights I, the creator of this work, hereby release it into the public domain. ... A hybrid vehicle (HV) is a vehicle that uses two or more distinct power sources such as: An on-board rechargeable energy storage system (RESS) and a fueled power source for vehicle propulsion Human powered bicycle with battery assist A sail boat with electric power[1] The term most commonly... Roadway noise is the most prevalent form of environmental noise. ... A hybrid vehicle (HV) is a vehicle that uses two or more distinct power sources such as: An on-board rechargeable energy storage system (RESS) and a fueled power source for vehicle propulsion Human powered bicycle with battery assist A sail boat with electric power[1] The term most commonly... Highway in Pennsylvania, USA The Pan-American Highway, in the Peruvian town of Máncora, where it serves as the main street. ... Karl Benzs Velo (vélo means bicycle in French) model (1894) - entered into the first automobile race 2005 MINI Cooper S. An automobile (also motor car or simply car) is a wheeled passenger vehicle that carries its own motor. ... Aerodynamics is a branch of fluid dynamics concerned with the study of gas flows, first analysed by George Cayley in the 1800s. ... A tire or tyre (see spelling differences and etymological origins) is a device covering the circumference of a wheel. ... The tread of a tire or caterpillar track refers to the pattern visible on its circumference that makes contact with the road. ... The driver of this DAF tractor with an auto-transport semi-trailer truck prepares to offload Škoda Octavia cars in Cardiff, Wales For other articles with similar names, see Lorry (disambiguation) and Truck (disambiguation). ...

The most fertile area for roadway noise mitigation is in urban planning decisions, roadway design, noise barrier design^[1], speed control, surface pavement selection and truck restrictions. Speed control is effective since the lowest sound emissions arise from vehicles moving smoothly at 30 to 60 kilometres per hour. Above that range sound emissions double with each five miles per hour of speed. At the lowest speeds, braking and (engine) acceleration noise dominates. Selection of surface pavement can make a difference of a factor of two in sound levels, for the speed regime above 30 kilometres per hour. Quieter pavements are porous with a negative surface texture and use medium to small aggregates; the loudest pavements have a transversely tined/grooved surface, and/or a positive surface texture and use larger aggregates. Obviously surface friction and roadway safety are important considerations as well for pavement decisions. Noise barrier earth berm along Highway 12, Sonoma County, California A noise barrier is an exterior structure, normally made of masonry or earth, designed to protect sensitive land uses from noise pollution. ...

When designing new urban freeways or arterials, there are numerous design decisions regarding alignment and roadway geometrics^[2], Use of a computer model to predict future sound levels from line sources has become standard practice since the early 1970s. In this way exposure of sensitive receptors to elevated sound levels can be minimized. An analogous process exists for urban mass transit systems and other rail transportation decisions. Early examples of urban rail systems designed using this technology were: Boston MTA line expansions (1970s), San Francisco Bay Area Rapid Transit System expansion (1981), Houston light rail system (1982), Portland, Oregon Beaverton light rail line (1983). A computer simulation or a computer model is a computer program which attempts to simulate an abstract model of a particular system. ... North-South Expressway in Malaysia; a roadway can be considered as a line source of air and noise pollution and need not be a straight line. ... In the United States of America, transit describes local area common carrier passenger transportation configured to provide scheduled service on fixed routes on a non-reservation basis. ... Nickname: City on the Hill, Beantown, The Hub (of the Universe)1, Athens of America, The Cradle of Revolution, Puritan City, Americas Walking City Location in Massachusetts, USA Counties Suffolk County Mayor Thomas M. Menino(D) Area    - City 232. ... The Massachusetts Bay Transportation Authority (MBTA) is a body politic and corporate, and a political subdivision of the Commonwealth of Massachusetts [1] formed in 1964 to finance and operate most bus, subway, commuter rail and ferry systems in the greater Boston, Massachusetts, USA area. ... This page is a candidate for speedy deletion. ... A westbound BART train with aerodynamic design A car in downtown San Francisco. ... Houston redirects here. ... This article is about light rail systems in general. ... Nickname: City of Roses, Stumptown, Bridgetown, PDX Location in Multnomah County and the state of Oregon Coordinates: Country United States State Oregon County Multnomah County Incorporated February 8, 1851 Government  - Mayor Tom Potter Area  - City  145. ...

Noise barriers can be applicable for existing or planned surface transportation projects. They are probably the single most effective weapon in retrofitting an existing roadway, and commonly can reduce adjacent land use sound levels by ten decibels. A computer model is required to design the barrier since terrain, micrometeorology and other locale specific factors make the endeavor a very complex undertaking. For example, a roadway in cut or strong prevailing winds can produce a setting where atmospheric sound propagation is unfavorable to any noise barrier. Satellite image of Hurricane Hugo with a polar low visible at the top of the image. ...

Aircraft noise abatement

A British Airways Airbus A321, on landing approach to London Heathrow Airport, showing proximity to homes.

As in the case of roadway noise, surprisingly little progress has been made in source quieting of aircraft noise, other than elimination of gratuitously loud engine designs from the 1960s and earlier. Because of its velocity and volume, jet turbine engine exhaust defies any simple means of quieting. The most promising forms of aircraft noise abatement is through land planning, flight operations restrictions and residential soundproofing. Flight restrictions can take the form of preferred runway use; departure flight path and slope; and time of day restrictions. These tactics are sometimes controversial since they can impact aircraft safety, flying convenience and airline economics. British Airways Airbus A321 flies over Myrtle Avenue on its landing path to Heathrow runway 27L. Myrtle Avenue is on the south east edge of London (Heathrow) Airport. ... British Airways Airbus A321 flies over Myrtle Avenue on its landing path to Heathrow runway 27L. Myrtle Avenue is on the south east edge of London (Heathrow) Airport. ... For the 1930s airline of similar name, see British Airways Ltd. ... The Airbus A320 is a short-to-medium range commercial passenger aircraft manufactured by Airbus. ... London Heathrow Airport (IATA airport code: LHR, ICAO airport code: EGLL, and often simply Heathrow) is the United Kingdoms busiest and best-connected airport. ... Aircraft noise is defined as sound produced by any aircraft on run-up, taxiing, take off, over flying or landing. ... Soundproofing is any means of to reducing the intensity of sound with respect to a specified source and receptor. ...

In 1979 the U.S. Congress authorized^[3] the FAA to devise technology and programs to attempt to insulate homes near airports. While this obviously does not aid the exterior environment, the program has been effective for residential and school interiors. Some of the first airports at which the technology was applied were San Francisco International Airport^[4], Seattle-Tacoma International Airport, John Wayne International Airport and San Jose International Airport^[5] in California. The underlying technology is a computer model which simulates the propagation of aircraft noise and its penetration into buildings. Variations in aircraft types, flight patterns and local meteorology can be analyzed along with benefits of alternative building retrofit strategies such as roof upgrading, window glazing improvement, fireplace baffling, caulking construction seams and other measures. The computer model allows cost effectiveness evaluations of a host of alternative strategies. The Congress of the United States is the legislative branch of the federal government of the United States of America. ... FAA may refer to: Federal Aviation Administration in the United States Fleet Air Arm in the UK Royal Navy Fuerza Aérea Argentina in Argentina This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... FAA diagram of SFO “SFO” redirects here. ... Seattle-Tacoma International Airport (IATA: SEA, ICAO: KSEA), also known as Sea-Tac Airport, is located in SeaTac, Washington, United States at the intersections of Washington State Route 518, Washington State Route 99 and Washington State Route 509. ... John Wayne-Orange County Airport (IATA Airport Code SNA) is located in Orange County, California, between the cities of Santa Ana, Newport Beach, Costa Mesa, and Irvine. ... For the Costa Rican airport, see Juan Santamaría International Airport. ... A computer simulation or a computer model is a computer program which attempts to simulate an abstract model of a particular system. ... Retrofitting is a term used in e. ... Glazing, in architecture, is a transparent part of a wall, usually made of glass or plastic (acrylic and polycarbonate). ... A natural gas fireplace with a burning fire. ... For a description of caulking in computer game creation, refer to caulking (computer games) Caulking is a process used in the sealing of the seams in wooden boats and making them watertight. ...

In year 1998 the flight paths in all of Scandinavia were changed as the new Oslo-Gardermoen Airport was opened. These new paths were straighter, consuming less fuel, and disturbing fewer people. However heavy protests came from people who weren't disturbed before, and they took legal action etc (NIMBY effect). Scandinavia is a historical and geographical region centered on the Scandinavian Peninsula in Northern Europe and includes the three kingdoms of Denmark, Norway and Sweden. ... Oslo Airport, Gardermoen (IATA: OSL, ICAO: ENGM) (Norwegian: Oslo lufthavn, Gardermoen) is located in Gardermoen in Ullensaker, Norway, 48 km north of Oslo. ... NIMBY (an acronym of Not In My Back Yard) describes the phenomenon in which residents oppose a development as inappropriate for their local area, but by implication do not oppose such development in anothers. ...

Architectural solutions

Main article: Architectural acoustics

Choices of stud construction, insulation and isolation of plumbing assemblies can reduce interior noise

Beyond the interior acoustics cited above under aircraft noise, there has been a steady trend to design quieter buildings with regard to sources within and without the structure itself. In the case of construction of new (or remodeled) apartments, condominiums, hospitals and hotels many states and cities have stringent building codes with requirements of acoustical analysis, in order to protect building occupants. With regard to exterior noise, the codes usually require measurement of the exterior acoustic environment in order to determine the performance standard required for exterior building skin design. The architect can work with the acoustical scientist to arrive at the best cost effective means of creating a quiet interior (normally 45 dBA). The most important elements of design of the building skin are usually: glazing (glass thickness, double pane design etc.), roof material, caulking standards, chimney baffles, exterior door design, mail slots, attic ventilation ports and mounting of through the wall air conditioners. It has been suggested that Acoustic transmission be merged into this article or section. ... Image File history File links Download high resolution version (2272x1712, 497 KB) File links The following pages link to this file: Light-frame construction ... Image File history File links Download high resolution version (2272x1712, 497 KB) File links The following pages link to this file: Light-frame construction ... Thermal insulation on the Huygens probe The term thermal insulation can refer to materials used to reduce the rate of heat transfer, or the methods and processes used to reduce heat transfer. ... A plumber wrench for working on pipes and fittings Plumbing, from the Latin for lead (plumbum), is the skilled trade of working with pipes, tubing and plumbing fixtures for potable water systems and the drainage of waste. ... An apartment estate in Singapore; such blocks make up the majority of public housing in Singapore. ... A condominium, or condo for short, is a form of housing tenure. ... A physician visiting the sick in a hospital. ... Dariush Grand Hotel,Kish island, Iran The 4-star Manor House Hotel at Castle Combe, Wiltshire, England. ... DBA may mean: // Decibels audible Diamond-Blackfan anemia Dibenzylideneacetone .dba format, a calendar format for Palm Desktop Doctor of Business Administration, an academic doctoral degree dba, a low-cost German airline The Dallas Bar Association for lawyers in Texas, USA A database administrator (or analyst) A-weighted decibels (dBA), in... Glazing, in architecture, is a transparent part of a wall, usually made of glass or plastic (acrylic and polycarbonate). ... A chimney is a system for venting hot gases and smoke from a boiler, stove, furnace or fireplace to the outside atmosphere. ... A typical attic. ... Return inlet (left)Supply outlet (right). ...

Regarding sound generated inside the building, there are two principal types of transmission. Firstly, airborne sound travels through walls or floor/ceiling assemblies and can emanate from either human activities in adjacent living spaces or from mechanical noise within the building systems. Human activities might include voice, amplified sound systems or animal noise. Mechanical systems are elevator systems, boilers, refrigeration or air conditioning systems, generators and trash compactors. Since many of these sounds are inherently loud, the principal design element is to require the wall or ceiling assembly to meet certain performance standards^[6] (typically Sound transmission class of 50), which allows considerable attenuation of the sound level reaching occupants. A set of lifts in the lower level of a London Underground station. ... A boiler is a closed vessel in which water or other fluid is heated under pressure. ... Refrigeration is the process of removing heat from an enclosed space, or from a substance, and rejecting it elsewhere for the primary purpose of lowering the temperature of the enclosed space or substance and then maintaining that lower temperature. ... Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ... An electrical generator is a device that converts mechanical energy to electrical energy, generally using electromagnetic induction. ... Sound Transmission Class (or STC) is an integer-number rating of how well a building partition isolates airborne sound. ...

The second type of interior sound is called Impact Insulation Class (IIC) transmission. This effect arises not from airborne transmission, but rather from transmission of sound through the building itself. The most common perception of IIC noise is from footfall of occupants in living spaces above. This type of noise is more difficult to abate, but consideration must be given to isolating the floor assembly above or hanging the lower ceiling on resilient channel.

Both of the above transmission effects may emanate either from building occupants or from building mechanical systems such as elevators, plumbing systems or heating, ventilating and air conditioning units. In some cases it is merely necessary to specify the best available quieting technology in selecting such building hardware. In other cases shock mounting of systems to control vibration may be in order. In the case of plumbing systems there are specific protocols developed, especially for water supply lines, to create isolation clamping of pipes within building walls. In the case of central air systems, it is important to baffle any ducts that could transmit sound between different building areas.

Designing special purpose rooms has more exotic challenges, since these rooms may have requirements for unusual features such as concert performance, sound studio recording, lecture halls. In these cases reverberation and reflection must be analyzed in order to not only quiet the rooms but prevent echo effects from occurring. In these situations special sound baffles and sound absorptive lining materials may be specified to dampen unwanted effects.. A classical music concert in the Rod Laver Arena, Melbourne 2005 A concert is a live performance, usually of music, before an audience. ... This article is about audio effect. ... A sound baffle is a construction or device which reduces the intensity of airborne sound. ...

Industrial noise mitigation

This situation classically is thought to involve primarily manufacturing settings where industrial machinery produces intense sound levels^[7], not uncommonly in the 75 to 85 decibel range. While this circumstance is the most dramatic, there are many other office type environments where sound levels may lie in the range of 70 to 75 decibels, entirely comprised of office equipment, music, public address systems, and even exterior noise intrusion. The latter environments can also produce noise health effects provided that exposures are long term. Environmental noise can produce irreversible hearing loss Noise health effects, the collection of health consequences of elevated sound levels, constitute one of the most widespread public health threats in industrialized countries. ...

In the case of industrial equipment, the most common techniques for noise protection of workers consist of shock mounting source equipment, creation of acrylic glass or other solid barriers, and provision of ear protection equipment. In certain cases the machinery itself can be re-designed to operate in a manner less prone to produce grating, grinding, frictional or other motions that induce sound emissions. Polymethyl methacrylate (PMMA) or poly (methyl 2-methylpropenoate) is the synthetic polymer of methyl methacrylate. ...

In the case of more conventional office environments, the techniques in architectural acoustics discussed above may apply. Other solutions may involve researching the quietest models of office equipment, particularly printers and photocopy machines. One source of annoying, if not loud, sound level emissions are certain types of lighting fixtures (notably older fluorescent globes). These fixtures can be retrofitted or analyzed to see whether over-illumination is present, a common office environment issue. If over-illumination is occurring, de-lamping or reduced light bank usage may apply. This cosmetics store has lighting levels over twice recommended levels and sufficient to trigger headaches and other health effects Over-illumination is the presence of lighting intensity (illuminance) beyond that required for a specified activity. ...

References

Noise barrier earth berm along Highway 12, Sonoma County, California A noise barrier is an exterior structure, normally made of masonry or earth, designed to protect sensitive land uses from noise pollution. ... FAA diagram of SFO “SFO” redirects here. ... FAA may refer to: Federal Aviation Administration in the United States Fleet Air Arm in the UK Royal Navy Fuerza Aérea Argentina in Argentina This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... For the Costa Rican airport, see Juan Santamaría International Airport. ... Traditionally, workplace noise has been a hazard linked to heavy industries such as ship-building and associated only with noise induced hearing loss (NIHL). ...

See also

• Building design
• Noise health effects
• Noise pollution
• Noise regulation
• Industrial noise
• Sound wall

Building design is the design of architectural exterior/interior spaces, engineered elements and shelter design. ... Environmental noise can produce irreversible hearing loss Noise health effects, the collection of health consequences of elevated sound levels, constitute one of the most widespread public health threats in industrialized countries. ... Noise pollution, usually called environmental noise in technical venues, is displeasing human or machine created sound that disrupts the environment. ... Noise regulation includes statutes or guidelines relating to sound transmission established by national, state or provincial and municipal levels of government. ... Traditionally, workplace noise has been a hazard linked to heavy industries such as ship-building and associated only with noise induced hearing loss (NIHL). ... There are very few or no other articles that link to this one. ...

External links

• Addressing Wind Turbine Noise

• Acoustical Society of America
• American Institute of Architects
• National Council of Acoustical Consultants
• Business & Institutional Furniture Manufacturer's Association
• Cambridge Sound Management