ENVIRONMENTAL CONTROL: ACOUSTICS AND NOISE CONTROL

(Arc 507)

OUTDOOR ACOUSTIC STANDARD

AN

ESSAY

COMPILED

BY

OGUNDIPE OLUWASEUN SUNDAY (ARC/04/3207)

BARUWA SEGUN TUNDE (ARC/03/1917)

SUBMITTED TO

PROF O.O OGUNSOTE.

OF

THE DEPARTMENT OF ARCHITECTURE,

SCHOOL OF ENVIRONMENTAL TECHNOLGY, FEDERAL UNIVERSITY OF TECHNOLOGY,

AKURE, ONDO STATE.

MARCH, 2008.

ABSTRACT External noise pollution has become a thing of rapid growth, which in no time would be a great cause of health defects on the living beings. However the technological efforts by both the developed and the developing countries to curb this ugly daily activity has been proven quite impressive especially with the manufacture of sound barriers to most outdoor activities. The essay illustrates acoustics, highlights the various codes and laws that standardized the production of noise externally, it also expatiates on the major causes of outdoor noise. Conclusive, this essay points out some of the useful sound reducing elements for the heavy activities done outside the walls of the buildings.

INTRODUCTION

Acoustics is the interdisciplinary science that deals with the study of sound, ultrasound and infrasound (all mechanical waves in gases, liquids, and solids). A scientist who works in the field of acoustics is an acoustician. The application of acoustics in technology is called acoustical engineering. There is often much overlap and interaction between the interests of acousticians and acoustical engineers.It is more commonly used for the special branch of that science, architectural acoustics that deals with the construction of enclosed areas so as to enhance the hearing of speech or music.

Architectural acoustics is the science of controlling sound within buildings. The first application of architectural acoustics was in the design of opera houses and then concert halls. More widely, noise suppression is critical in the design of multi-unit dwellings and business premises that generate significant noise, including music venues like bars. The more mundane design of workplaces has implications for noise health effects.

Acoustical design must take into consideration that in addition to physiological peculiarities of the ear, hearing is complicated by psychological peculiarities. For example, sounds that are unfamiliar seem unnatural. Sound produced in an ordinary room is somewhat modified by reverberations due to reflections from walls and furniture; for this reason, a broadcasting studio should have a normal degree of reverberation to ensure natural reproduction of sound. For best acoustic qualities, rooms are designed to produce sufficient reflections for naturalness, without introducing excessive reverberation at any frequency, without echoing certain frequencies unnaturally, and without producing undesirable interference effects or distortion

Hearing is one of the most crucial means of survival in the animal world, and speech is one of the most distinctive characteristics of human development and culture. So it is no surprise that the science of acoustics spreads across so many facets of our society - music, medicine, architecture, industrial production, warfare and more. Art, craft, science and technology have provoked one another to advance the whole, as in many other fields of knowledge.

http://en.wikipedia.org/wiki/Soundhttp://en.wikipedia.org/wiki/Ultrasoundhttp://en.wikipedia.org/wiki/Infrasoundhttp://en.wikipedia.org/wiki/Acoustical_engineeringhttp://en.wikipedia.org/wiki/Opera_houseshttp://en.wikipedia.org/wiki/Concert_hallhttp://en.wikipedia.org/wiki/Workplacehttp://en.wikipedia.org/wiki/Noise_health_effectshttp://en.wikipedia.org/wiki/Hearinghttp://en.wikipedia.org/wiki/Speech

FUNDAMENTAL CONCEPTS OF ACOUSTICS

The study of acoustics revolves around the generation, propagation and reception of mechanical waves and vibrations.

The steps shown in the above diagram can be found in any acoustical event or process. There are many kinds of cause, both natural and volitional. There are many kinds of transduction process that convert energy from some other form into acoustical energy, producing the acoustic wave. There is one fundamental equation that describes acoustic wave propagation, but the phenomena that emerge from it are varied and often complex. The wave carries energy throughout the propagating medium. Eventually this energy is transduced again into other forms, in ways that again may be natural and/or volitionally contrived. The final effect may be purely physical or it may reach far into the biological or volitional domains.

OUTDOOR ACOUSTIC STANDARDS

Outdoor acoustic standards includes statutes or guidelines relating to sound transmission established by national, state or provincial and municipal levels of government. After a watershed passage of the U.S. Noise Control Act of 1972, the program was abandoned at the federal level, under President Ronald Reagan, in 1981 and the issue was left to local and state governments. Although the UK and Japan enacted national laws in 1960 and 1967 respectively, these laws were not at all comprehensive or fully enforceable as to address (a) generally rising ambient noise (b) enforceable numerical source limits on aircraft and motor vehicles or (c) comprehensive directives to local government.

HISTORY OF OUTDOOR ACOUSTIC STANDARDS

Sound level meter, a basic tool in measuring sound.

In the 1960s and earlier, few people recognized that citizens might be entitled to be protected from adverse sound level exposure. Most concerted actions consisted of citizens groups organized to oppose a specific highway or

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airport, and occasionally a nuisance lawsuit would arise. Things in the United States changed rapidly with passage of the National Environmental Policy Act (NEPA) in 1969 and the Noise Pollution and Abatement Act (more commonly called the Noise Control Act (NCA) of 1972) Passage of the NCA was remarkable with the lack of historic organized citizen concern; however, EPA had testified before congress that 30 million Americans are exposed to non-occupational noise high enough to cause hearing loss and 44 million Americans live in homes impacted by aircraft or highway noise. Initially these laws had a significant effect on thoughtful study of transportation programs and also federally funded housing programs in the United States. They also gave states and cities an impetus to consider environmental noise in their planning and zoning decisions, and led to a host of statutes below the federal level. Awareness of the need for noise control was rising; in fact, by 1973 a national poll of 60,000 U.S. residents found that sixty percent of people considered street noise to have a disturbing, harmful or dangerous impact.

National controls

After the passage of the NCA, EPA busily promulgated regulations setting maximum noise limits on a gamut of motor vehicles, industrial machinery and household appliances. They conducted extensive testing and involved industry in the practicality of manufacturing quieter devices. They had an influence on the future of a quieter generation of machines; however, roadway noise and aircraft noise account for the lions share of noise emissions, and the EPA standards for those vehicles pre-empted states from further regulating; moreover, in the case of aircraft noise, FAA had veto power over EPA recommendations, so those standards never pushed the envelope. In the case of airport expansions, the power structure came down differently, because courts consistently upheld the sovereignty of the FAA over the EPA, in allowing air traffic needs to be met over environmental concerns.

State and local planning

States passed two different types of legislation starting in the 1970s, echoing the federal lead in noise control. Firstly many states, with California in the vanguard, began requiring each municipality and county to have a Noise Element of the General Plan, a substantial noise data base and blueprint for making land use decisions in that jurisdiction. The Noise Element became an integral part of the municipal or county General Plan, especially in California. This document compiled a comprehensive set of measurements setting forth existing sound levels, frequently in the form of sound level contour maps to illustrate where varying sound levels fall relative to land use categories. Cities and counties in the U.S. who either fell under state mandates or who voluntarily chose to control noise through land use decisions, were active in mapping sound levels and seeking development strategies that would minimize the number of persons exposed to harmful levels of (primarily) motor vehicle noise.

Local outdoor acoustic ordinances

Principally aimed at construction noise, power equipment of individuals and unmuffled industrial noise penetrating residential areas. Thousands of U.S. cities have prepared noise ordinances that give noise control officers and police the power to investigate noise complaints and enforcement power to abate the offending noise source, through shutdowns and fines.[6] A typical noise ordinance sets forth clear definitions of acoustics nomenclature and defines categories of noise generation; then numerical standards are established, so that enforcement personnel can take the necessary steps of warnings, fines or other municipal police power to rectify unacceptable noise generation. Ordinances have achieved certain successes but they can be thorny to implement. Many European cities are still treating noise as the U.S. did in the 1960s, as a nuisance and not as a numerical standard to be achieved.

http://en.wikipedia.org/wiki/National_Environmental_Policy_Acthttp://en.wikipedia.org/wiki/United_States_Environmental_Protection_Agencyhttp://en.wikipedia.org/w/index.php?title=Occupational&action=edithttp://en.wikipedia.org/wiki/Hearing_losshttp://en.wikipedia.org/wiki/Transportationhttp://en.wikipedia.org/wiki/Housinghttp://en.wikipedia.org/wiki/Zoninghttp://en.wikipedia.org/wiki/Roadway_noisehttp://en.wikipedia.org/wiki/Aircraft_noisehttp://en.wikipedia.org/wiki/Airporthttp://en.wikipedia.org/w/index.php?title=Noise_Element&action=edithttp://en.wikipedia.org/wiki/Sound_levelhttp://en.wikipedia.org/wiki/Contour_linehttp://en.wikipedia.org/wiki/Land_usehttp://en.wikipedia.org/wiki/Motor_vehiclehttp://en.wikipedia.org/wiki/Constructionhttp://en.wikipedia.org/wiki/Industrial_noisehttp://en.wikipedia.org/wiki/Local_ordinancehttp://en.wikipedia.org/wiki/Noise_controlhttp://en.wikipedia.org/wiki/Policehttp://en.wikipedia.org/wiki/Noise_regulation#_note-4#_note-4http://en.wikipedia.org/wiki/Enforcement

OUTDOOR ACOUSTIC BUILDING CODES

In the case of construction of new (or remodeled) apartments, condominiums, hospitals and hotels many US states and cities have stringent building codes with requirements of acoustical analysis, in order to protect building occupants from (a) exterior noise sources and (b) sound generated within the building itself[7]. 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 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 somewhat more difficult to abate, but consideration must be given to isolating the floor assembly above or hanging the lower ceiling on resilient channel. Commonly a performance standard of IIC equal to 50 is specified in building codes.

OUTDOOR ACOUSTIC CONTROL

Outdoor noise reduction usually involves blocking noise from highway construction, traffic or mechanical equipment (air conditioners, chillers, etc.). In most states, when they are doing highway construction they put up sound barrier walls to shield or block noise from reaching the residential neighborhoods nearby. Highway noise barrier walls are used when busy interstates and highways are built near highly populated residential areas. When outdoor soundproofing is needed from mechanically generated noise, acoustical enclosures and outdoor sound barriers are most often used.

Inter-space acoustics control

The science of limiting and/or controlling noise transmission from one building space to another to ensure space functionality and speech privacy. The typical sound paths are room partitions, acoustic ceiling panels (such as wood dropped ceiling panels), doors, windows, flanking, ducting and other penetrations. An example would be providing suitable party wall design in an apartment complex to minimize the mutual disturbance due to noise by residents in adjacent apartments.

Interior space acoustics

This is the science of controlling a room's surfaces based on sound absorbing and reflecting properties. Excessive reverberation time, which can be calculated, can lead to poor speech intelligibility [1]. Reflective surfaces can be angled and coordinated to provide good coverage of sound for a listener in a concert hall or music recital space. To illustrate this concept consider the difference between a modern large office meeting room or lecture theater and a traditional classroom with all hard surfaces. Interior building surfaces can be constructed of many different materials and finishes. Ideal acoustical panels are those without a face or finish material that interferes with the acoustical infill or substrate. Fabric covered panels are one way to heighten acoustical absorption. Finish material is used to cover over the acoustical substrate.

Building skin envelope

This science analyzes noise transmission from building exterior envelope to interior and vice versa. The main noise paths are roofs, eaves, walls, windows, door and penetrations. Sufficient control ensures space functionality and is often required based on building use and local municipal codes. An example would be providing a suitable design for a home which is to be constructed close to a high volume roadway, or under the flight path of a major airport, or of the airport itself.

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HEALTH EFFECTS OF UNCONTROLLED OUTDOOR ACOUSTICS

Uncontrolled outdoor acoustics are the health consequences of elevated sound levels. Elevated workplace or other noise can cause hearing impairment, hypertension, ischemic heart disease, annoyance, sleep disturbance, and decreased school performance. Changes in the immune system and birth defects have been attributed to noise exposure, but evidence is limited. Although some presbycusis may occur naturally with age, in many developed nations the cumulative impact of noise is sufficient to impair the hearing of a large fraction of the population over the course of a lifetime. But also are known to induce tinnitus, hypertension, vasoconstriction and other cardiovascular impacts. Beyond these effects, elevated noise levels can create stress, increase workplace accident rates, and stimulate aggression and other anti-social behaviors. The most significant causes are vehicle and aircraft noise, prolonged exposure to loud music, and industrial noise.

HEARING LOSS

Hearing loss is somewhat inevitable with age. Though older males exposed to significant occupational noise demonstrate significantly reduced hearing sensitivity than their non-exposed peers, differences in hearing sensitivity decrease with time and the two groups are indistinguishable by age 79. Women exposed to occupational noise do not differ from their peers in hearing sensitivity, though they do hear better than their non-exposed male counterparts. Due to loud music and a generally noisy environment, young people in the United States have a rate of impaired hearing 2.5 times greater than their parents and grandparents, with an estimated 50 million individuals with impaired hearing estimated in 2050. The mechanism of hearing loss arises from trauma to stereo cilia of the cochlea, the principal fluid filled structure of the inner ear.

CARDIOVASCULAR EFFECTS

Noise has been associated with important cardiovascular health problems. In 1999, the World Health Organization concluded that the available evidence showed suggested a weak association between long-term noise exposure above 67-70 dB (A) and hypertension. More recent studies have suggested that noise levels of 50 dB(A) at night may also increase the risk of myocardial infarction by chronically elevating cortisol production. Fairly typical roadway noise levels are sufficient to constrict arterial blood flow and lead to elevated blood pressure; in this case, it appears that a certain fraction of the population is more susceptible to vasoconstriction. This may result because annoyance from the sound causes elevated adrenaline levels trigger a narrowing of the blood vessels (vasoconstriction), or independently through medical stress reactions. Other effects of high noise levels are increased frequency of headaches, fatigue, stomach ulcers and vertigo.

ANNOYANCE

Because some stressful effects depend on qualities of the sound other than its absolute decibel value, the annoyance associated with sound may need to be considered in regard to health effects. For example, noise from airports is typically perceived as more bothersome than noise from traffic of equal volume. Annoyance effects of noise are minimally affected by demographics, but fear of the noise source and sensitivity to noise both strongly affect the 'annoyance' of a noise. Even sound levels as low as 40 dB(A) (about as loud as a refrigerator or library can generate noise complaints and the lower threshold for noise producing sleep disturbance is 45 dB(A) or lower. Other factors that affect the 'annoyance level' of sound include beliefs about noise prevention and the importance of the noise source, and annoyance at the cause (i.e. non-noise related factors) of the noise. Estimates of sound annoyance typically rely on weighting filters, which consider some sound frequencies to be more important than others based on their presumed audibility to the human ear.

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MAJOR SOURCES OF OUTDOOR ACOUSTICS

1. AIRCRAFT

Qantas Boeing 747-400 passes close to houses on the boundary of London Heathrow Airport, England

Aircraft noise is defined as sound produced by any aircraft on run-up, taxiing, take off, over-flying or landing. Aircraft noise is a significant concern for approximately 100 square kilometers (65 square miles) surrounding most major airports. Aircraft noise is the second largest (after roadway noise) source of environmental noise. While commercial aviation produces the preponderance of total aircraft noise, private aviation and military operations also play a role. It is usually measured in Decibels.

Take-off of aircraft may lead to a sound level of more than 100 decibels at the ground, with approach and landing creating lower levels. Since aircraft landing in inner-city airports are often lower than 60 meters (200 feet) above roof level, a sound level above 100 dBA can be realized.

Mechanisms of Aircraft sound production

A moving aircraft including the jet engine or propeller causes compression and rarefaction of the air, producing motion of air molecules. This movement propagates through the air as pressure waves. If these pressure waves are strong enough and within the audible frequency spectrum, a sensation of hearing is produced. Different aircraft types have different noise levels and frequencies. The noise originates from three main sources:

Aerodynamic noise Engine and other mechanical noise Noise from aircraft systems

Aerodynamic noise

Aerodynamic noise arises from the airflow around the aircraft fuselage and control surfaces. This type of noise increases with aircraft speed and also at low altitudes due to the density of the air. Jet-powered aircraft create intense noise from aerodynamics, which is typically broadband. Low flying, high speed military aircraft produce especially loud aerodynamic noise. The shape of the nose, windshield or canopy of an aircraft affects the sound produced. Much of the noise of a propeller aircraft is of aerodynamic origin due to the flow of air around the blades. The helicopter main and tail rotors also give rise to aerodynamic noise. This type of aerodynamic noise is mostly low frequency determined by the rotor speed.

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Engine and other mechanical noise

Much of the noise in propeller aircraft comes equally from the propellers and aerodynamics. Helicopter noise is aerodynamically induced noise from the main and tail rotors and mechanically induced noise from the main gearbox and various transmission chains. The mechanical sources produce narrow band high intensity peaks relating to the rotational speed and movement of the moving parts. In computer modelling terms noise from a moving aircraft can be treated as a line source.

Noise from aircraft systems

Cockpit and cabin pressurization and conditioning systems are often a major contributor within cabins of both civilian and military aircraft. However, one of the most significant sources of cabin noise from commercial jet aircraft other than the engines is the Auxiliary Power Unit (or APU). An Auxiliary Power Unit is an on-board generator used in aircraft to start the main engines, usually with compressed air, and to provide electrical power while the aircraft is on the ground. Other internal aircraft systems can also contribute, such as specialised electronic equipment in some military aircraft.

Aircraft Noise mitigation programs

In the United States, since aviation noise became a public issue in the late 1960s, governments have enacted legislative controls. Aircraft designers, manufacturers, and operators have developed quieter aircraft and better operating procedures. Modern high-bypass turbofan engines, for example, are quieter than the turbojets and low-bypass turbofans of the 1960s. First, FAA Aircraft Certification achieved noise reductions classified as 'Stage 3' aircraft; which has been upgraded to 'Stage 4' noise certification resulting in quieter aircraft. This has resulted in lower noise exposures in spite of increased traffic growth and popularity.

2. VEHICULAR MOVEMENTS

Roadway noise is the most prevalent form of environmental noise. Pictured: Sao Paulo, Brazil, and Hong Kong roadway

generating noise to adjacent land uses

Roadway noise is the collective sound energy emanating from motor vehicles. In the USA it contributes more to environmental noise exposure than any other noise source, and is constituted chiefly of engine, tire, aerodynamic and braking elements. In other Western countries as well as lesser developed countries, roadway noise is expected to contribute a proportionately large share of the total societal noise pollution.

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History

Roadway noise began to be measured in a widespread manner in the 1960s, when computer modeling of this phenomenon was perfected. After passage of the National Environmental Policy Act and Noise Control Act, the demand for detailed analysis soared, and decision makers began to look to acoustical scientists for answers regarding the planning of new roadways and the design of noise mitigation. Partial bans on motor vehicles from urban areas have been shown to have minimal impacts upon reducing sound levels (as would become clear from later modeling studies); for example, the partial ban in Gothenburg, Sweden resulted in minuscule reduction of sound levels.

Description of basic variables

The intensity of roadway noise is governed by the following variables: traffic operations (speed, truck mix, age of vehicle fleet), roadway surface type, tire types, roadway geometrics, terrain, micrometeorology and the geometry of area structures.

Traffic operations noise is affected significantly by vehicle speeds, since sound energy roughly doubles for each increment of ten miles an hour in vehicle velocity; an exception to this rule occurs at very low speeds where braking and acceleration noise dominate over aerodynamic noise. Small reductions in vehicle noise occurred in the 1970s as states and provinces enforced unmuffled vehicle ordinances. The vehicle fleet noise has not changed very much over the last three decades; however, if the trend in hybrid vehicle use continues, substantial noise reduction will occur, especially in the regime of traffic flow below 35 miles per hour.

Roadway surface types contribute differential noise effects of up to 4 dB, with chip seal type and grooved roads being the loudest and concrete surfaces without spacers being the quietest. Asphaltic surfaces are about average.

Tire types had considerable design changes in the 1970s, and at this juncture are probably optimized for noise control, given the of safety needs for a significant grip by the tread.

Roadway geometrics and surrounding terrain are interrelated, since the propagation of sound is sensitive to the overall geometry and must consider diffraction (bending of sound waves around obstacles), reflection, ground wave attenuation, spreading loss and refraction. A simple discussion indicates that sound will be diminished when the path of sound is blocked by terrain, or will be enhanced if the roadway is elevated so as to broadcast; however, the complexities of variable interaction are so great, that there are many exceptions to this simple argument.

Geometry of area structures is an important input, since the presence of buildings or walls can block sound under certain circumstances, but reflective properties can augment sound energy at other locations.

Computer models for roadway noise

Because of the complexity of the variables discussed, it is necessary to create a computer model that can analyze sound levels in the vicinity of roadways. The first meaningful models arose in the late 1960s and early 1970s addressing the noise line source (e.g. roadway). Two of the leading research teams were BBN in Boston and ESL of Sunnyvale, California. Both of these groups developed complex mathematical models to allow the study of alternate roadway designs, traffic operations and noise mitigation strategies in an arbitrary setting. Later model alterations have come into widespread use among state Departments of Transportation and city planners, but the accuracy of early models has had little change in 40 years.

http://en.wikipedia.org/wiki/Computer_modelhttp://en.wikipedia.org/wiki/National_Environmental_Policy_Acthttp://en.wikipedia.org/wiki/Noise_Control_Acthttp://en.wikipedia.org/wiki/Noise_mitigationhttp://en.wikipedia.org/wiki/Gothenburg%2C_Swedenhttp://en.wikipedia.org/wiki/Traffichttp://en.wikipedia.org/wiki/Truckhttp://en.wikipedia.org/wiki/Vehiclehttp://en.wikipedia.org/wiki/Hybrid_vehiclehttp://en.wikipedia.org/w/index.php?title=Concrete_surface&action=edithttp://en.wikipedia.org/wiki/Asphalthttp://en.wikipedia.org/wiki/Diffractionhttp://en.wikipedia.org/wiki/Reflection_%28physics%29http://en.wikipedia.org/wiki/Ground_wavehttp://en.wikipedia.org/wiki/Ground_wavehttp://en.wikipedia.org/wiki/Refractionhttp://en.wikipedia.org/wiki/Terrainhttp://en.wikipedia.org/wiki/Computer_modelhttp://en.wikipedia.org/wiki/Line_sourcehttp://en.wikipedia.org/wiki/BBNhttp://en.wikipedia.org/wiki/Bostonhttp://en.wikipedia.org/wiki/ESL_Incorporatedhttp://en.wikipedia.org/wiki/Sunnyvale%2C_Californiahttp://en.wikipedia.org/wiki/Mathematical_modelhttp://en.wikipedia.org/wiki/Noise_mitigationhttp://en.wikipedia.org/wiki/Department_of_transportation

3 TRAIN.

Trains are series of connected railroad cars pushed or pulled by one or more locomotives. Railroads are roads on which trains of freight and passenger cars, drawn by locomotives, travel on tracks formed by pairs of parallel metal rails. The term railroad is often extended to include the rolling stock, or cars and locomotives, and the land, buildings, and equipment owned or operated in conjunction with the railroad lines. The terms railroad and railway are interchangeable in the United States Light-rail transit is an electric railway system that evolved from streetcar systems. Like streetcars, light-rail cars operate as single units or as short trains of two or three cars. Light rail is designed to use a variety of rights-of-way, providing more flexibility than the streetcar. In some cities, light-rail systems operate like streetcars in downtown areas but then move to reserved lanes of traffic to service outer neighborhoods. Light-rail systems may also operate in tunnels under congested areas or on elevated tracks mounted over city streets. Heavy-rail transit is also commonly referred to as rail rapid transit. Subways (often called metros outside of the United States) are common examples, although rail rapid-transit systems may also operate above ground, as parts of the New York City and Chicago, Illinois, subway systems do. Heavy-rail systems typically consist of large four-axle rail vehicles operating in trains of two to ten cars. Rail rapid-transit systems operate on tracks reserved solely for the rail cars, and so the trains are able to travel at high speeds. Commuter rail transit uses traditional freight railroad technology, including diesel or electric locomotives, to operate trains for passenger service. Commuter rail systems generally operate only during peak hours, transporting workers between downtown areas of major cities and nearby suburbs. The rail lines used by a commuter rail system may have been abandoned for freight service or may be operated for freight use during noncommute times. Government Regulation of Railroads, regulation by state and federal governments of the rates, service, operation, finance, construction and abandonment, and consolidation of railroads in the United States. The railroad industry initially used the corporate form of organization under charters granted by the legislatures of one or more states. These charters, the means by which state regulation was applied, contained provisions relating to rates, safety, financial administration, and service. Charter regulation failed, primarily because of inflexibility. State regulation About 1850 state regulation began to take statutory form. The Midwestern states, under pressure from the powerful fraternal agrarian association, the National Grange, took the lead in this type of regulation by enacting what were known as Granger Laws, which imposed regulation in the fields of rates, service, administration, and corporate structure. The Granger movement grew out of a number of grievances the farmers had against the railroads. Many farmers considered freight rates on agricultural commodities and return rates on manufactured commodities excessive. Federal regulation Regulation of railroads by the federal government originated with the passage in 1887 of the Act to Regulate Commerce, or Interstate Commerce Act. With amendments, that law is currently the principal vehicle of federal regulation. It sought to deal with certain basic problems that had developed under unrestricted competition. Among its provisions were prohibitions against, and penalties for, undue preference, discrimination, rebates, and

pooling; requirements that rates and charges be just and reasonable and that rate schedules be published and adherence to them be mandatory; a long-and-short haul rule prohibiting greater charges for a short haul than for a long haul over the same route in the same direction; and creation of the five-member Interstate Commerce Commission, or ICC, charged with enforcement of the act.

4. INDUSTRIAL & MANUFACTURING ACTIVITIES

The need for industrial acoustics include a wide array of noise barrier products and noise absorption products. The ultimate in cost-effective sound abatement within the industrial market is our Acoustic Blankets or Curtains. Stop noise in its tracks and prevent sound from traveling around rooms by fastening to walls. Prevent noise traveling through ceiling structures by hanging as baffles. Isolate noise around equipment with standard and custom enclosures. Durable enough for heavy construction, industrial in-plant noise abatement and community / outdoor applications and more. We even have the infamous acoustical blanket as a door cover. Excessive noise is one of the most common workplace hazards in industrial facilities.

Industrial noise is usually considered mainly from the point of view of environmental health and safety, rather than nuisance, as sustained exposure can cause permanent hearing damage. Traditionally, workplace noise has been a hazard linked to heavy industries such as ship-building and associated only with noise induced hearing loss (NIHL). Modern thinking in occupational safety and health identifies noise as hazardous to worker safety and health in many places of employment and by a variety of means. Noise can not only cause hearing impairment (at long-term exposures of over 85 decibels (dB)), but it also acts as a causal factor for stress and raises systolic blood pressure. Additionally, it can be a causal factor in work accidents, both by masking hazards and warning signals, and by impeding concentration.

CONTROL AND REDUCTION OF INDUSTRIAL ACOUSTICS.

Industrial noise control is a growing concern in factories, industrial sites, manufacturing and mining facilities. The goal for industrial noise control is to promote hearing conservation while reducing noise levels for personnel to protect employees from hearing loss and increase industrial safety within the facilities. Companies are required to comply with industrial safety noise levels within OSHA or other governmental or insurance agency requirements. Enclosures and machinery enclosures are a very common treatment for industrial noise control requirements. Acoustical Solutions custom fabricates all of their industrial enclosures to meet the requirements of the environment that it is going into.

The control of noise in industry is very important. There have been sharp increases in worker compensation claims for hearing damage, and legislative, safety and economic requirements make a noise reduction program essential for many industries. To meet these requirements and to help solve many in-plant noise problems, ArtUSA Noise Control manufactures a complete line of acoustical panels which can be quickly and easily assembled to provide

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complete or partial enclosures for noisy equipment or to provide a quiet office in a manufacturing area. These panels are designed to provide optimum noise control through sound absorption and sound transmission loss.

Industrial Installations

Claims for hearing damage, safety and economic requirements make a noise reduction program essential for many industries. In the past, many manufacturing facilities were regulated by a government agency such as OSHA, but today the vast majority of noise regulation is driven by insurance companies who seek to keep claims for hearing damage to a minimum for the facilities they insure.

5. METAL MANUFACTURING NOISE CONTROL

Noise induced hearing loss (NIHL) is still a cause of reduced quality of life for many metal workers. The 1998 International Labour Office Encyclopedia lists the metal industry as the fourth noisiest manufacturing industry. High noise levels with potentially damaging impact occur in many operations like grinding, punching, shearing, forming etc. Significant impact noises are also produced when handling material such as dumping sheared rods into racks, stacking sheet metal and dropping metal off cuts into metal recycling bins. Employers must, so far as is practicable, ensure that noise to which a person is exposed at the workplace does not exceed the exposure standard for noise (Occupational Safety and Health Regulation 3.46), namely an exposure equivalent to 85 dB(A) for 8 hours a day or a peak noise of 140 dB(C)

If you have to raise your voice to a shout to be understood by others one meter away, then the employer, in consultation with occupational safety and health representatives and other employees should list all the machines and activities that produce high noise levels. At this stage it can be decided if all those activities/machines are necessary and if they can be replaced by other, less noisy ones. If it is not possible to eliminate all the noise sources from the workplace then a risk assessment should be undertaken.

OUTDOOR NOISE CONTROL ELEMENTS.

Outdoor Noise Reduction Barrier Wall

The three-sided outdoor barrier wall is manufactured for schools using standard Galvanized construction with specialized structural support to meet wind load requirements and is approximately 45"x24"x30"x10"-16" (H). The large barrier wall is installed on roof enclosing chiller units. It provides the noise reduction necessary to accommodate close proximity neighbors and meets most city noise level requirements.

Acoustical Noise Control Pipe Wrap

The acoustical pipe wrap is used by cement companies and industrial plants to control the noise through indoor and outdoor ductwork.

Outdoor Soundproof Noise Control Curtain System

This is a two-sided heavy-duty acoustical curtain system, measuring approximately 28"x16"x12"(H) used mainly by for industrial installations where reduction of noise control from chiller units protruding towards their neighbors is necessary. The curtain system is installed at ground level with a structural system that is anchored into concrete pillars using wind flaps in curtain panels for relief of high winds.

Outdoor Soundproof Noise Control Curtain System

This three-sided rooftop acoustical noise control curtain system is used by schools with two chiller units to reduce the noise for their neighbors. It is a heavy-duty system with structural support and top valiance.

REFERENCES

A study of highway noise pollution in Tehran, M. Vaziri, Tehran, Iran

C.M. Hogan and Harry Seidman, Acoustics Impacts of the proposed New Jersey Turnpike Authority widening project through East Brunswick ESL Inc. 1973

C. Michael Hogan and Jorgen Ravnkilde, Design of acoustical insulation for existing residences in the vicinity of Municipal Airport, January 1, 1984, FAA grant funded research, ISBN B0007B2OG0

C.Michael Hogan, Analysis of highway noise, Journal of Water, Air, & Soil Pollution, Volume 2, Number 3, Biomedical and Life Sciences and Earth and Environmental Science Issue, Pages 387-392, September, 1973, Springer Verlag, Netherlands ISSN 0049-6979

John Shadely, Acoustical analysis of the New Jersey Turnpike widening project between Raritan and East Brunswick, Bolt Beranek and Newman, 1973

Public Law No. 92-574, 86 Stat. 1234 (1972)Noise Pollution and Abatement Act of 1972, codification amended at 42 U.S.C. 4901-4918 (1988)

S. Rosen and P. Olin, Hearing loss and coronary heart disease, Archives of Otolaryngology, 82:236 (1965)

TRB review of European Union progress on noise control

http://en.wikipedia.org/wiki/East_Brunswick%2C_New_Jerseyhttp://en.wikipedia.org/wiki/January_1http://en.wikipedia.org/wiki/1984http://www.springerlink.com/content/x1707075n815g604/http://www.springerlink.com/content/x1707075n815g604/http://www.springerlink.com/content/x1707075n815g604/http://en.wikipedia.org/wiki/New_Jersey_Turnpikehttp://en.wikipedia.org/wiki/Hearing_losshttp://en.wikipedia.org/wiki/Coronary_heart_diseasehttp://trb.org/news/search_news.asp?q_aw=Traffic+noise

FUNDAMENTAL CONCEPTS OF ACOUSTICS OUTDOOR ACOUSTIC STANDARDS HISTORY OF OUTDOOR ACOUSTIC STANDARDS National controls Local outdoor acoustic ordinances OUTDOOR ACOUSTIC BUILDING CODES OUTDOOR ACOUSTIC CONTROL Inter-space acoustics control Interior space acoustics HEALTH EFFECTS OF UNCONTROLLED OUTDOOR ACOUSTICS HEARING LOSS CARDIOVASCULAR EFFECTS

MAJOR SOURCES OF OUTDOOR ACOUSTICS 1. AIRCRAFT Mechanisms of Aircraft sound production Aerodynamic noise Engine and other mechanical noise Noise from aircraft systems

Aircraft Noise mitigation programs History Description of basic variables Computer models for roadway noise 4. INDUSTRIAL & MANUFACTURING ACTIVITIES The need for industrial acoustics include a wide array of noise barrier products and noise absorption products. The ultimate in cost-effective sound abatement within the industrial market is our Acoustic Blankets or Curtains. Stop noise in its tracks and prevent sound from traveling around rooms by fastening to walls. Prevent noise traveling through ceiling structures by hanging as baffles. Isolate noise around equipment with standard and custom enclosures. Durable enough for heavy construction, industrial in-plant noise abatement and community / outdoor applications and more. We even have the infamous acoustical blanket as a door cover. Excessive noise is one of the most common workplace hazards in industrial facilities. CONTROL AND REDUCTION OF INDUSTRIAL ACOUSTICS. Industrial noise control is a growing concern in factories, industrial sites, manufacturing and mining facilities. The goal for industrial noise control is to promote hearing conservation while reducing noise levels for personnel to protect employees from hearing loss and increase industrial safety within the facilities. Companies are required to comply with industrial safety noise levels within OSHA or other governmental or insurance agency requirements. Enclosures and machinery enclosures are a very common treatment for industrial noise control requirements. Acoustical Solutions custom fabricates all of their industrial enclosures to meet the requirements of the environment that it is going into. Industrial Installations

5. METAL MANUFACTURING NOISE CONTROL OUTDOOR NOISE CONTROL ELEMENTS. Outdoor Noise Reduction Barrier Wall Acoustical Noise Control Pipe Wrap Outdoor Soundproof Noise Control Curtain System Outdoor Soundproof Noise Control Curtain System

REFERENCES