Noise Barriers by ArtUSA

Visit our main site for details and specs www.noisecontrolproducts.com

ArtUSA Noise Control Products, Inc. is leading the nation in cost effective Noise Control, Noise Control Enclosures, Soundproofing, Sound Enclosures, Acoustical Materials, and Air Filtration Systems.

Visit our sister site www.artusaindustries.us

Our barrier products are

http://www.artusaindustries.us/barrier_walls.html

http://www.artusaindustries.us/facings_barriers.html

http://www.artusaindustries.us/facings_barriers.html

Barrier Walls are normally used to place a sound barrier between a noise source and a target population. Our barriers create a  zone of quiet that can be tailored to cover almost any size area either indoors or out. When you contact ArtUSA Noise Barriers, we work with you from beginning to end. Our goal isn’t to sell you equipment; it’s to create a solution for your particular problem. We’ll help design your barrier from the ground up to protect your particular environment at the lowest cost possible. Whether you need to protect an entire neighborhood or just a portion of one building, ArtUSA Noise Barriers  has a solution for you. Regardless of the size of your job, we have the right mix of one-sided or two-sided, sound absorbing or reflecting materials, to reduce noise levels without breaking your budget. Absorptive noise control barriers provide maximum noise reduction with lightweight modular panels and/or louvers. The noise barrier system is easy to install and easy to relocate. Panels and louvers are constructed of galvanized steel or  painted finish in a weather resistant paint or powder coating. The finish is also cleanable.

Our design services include layout, structural steel support framework, foundation design (for ground level barriers), access doors and certified calculations including P.E. or S.E. stamp. Perfect for new construction or retrofit to an existing structure.

Free-Standing or Elevated Panel Construction

• Allows for maximum flexibility of design and utility on the ground or on the rooftop
• One– or two-sided sound absorption
• Steel Stainless or Aluminum construction
• Perfect for retrofit installation to solve existing noise problems
• Low-weight construction ideal for roof or bridge mounted applications
• Designed to withstand high wind loads

All-Weather Applications

• Barrier modules are designed and built to minimize water invasion
• Panels resist “wicking” moisture through the bottom and are self-draining

Highway Traffic Noise Barriers at a Glance

Highway traffic noise barriers:

• can reduce the loudness of traffic noise by as much as half;
• do not completely block all traffic noise;
• can be effective, regardless of the material used;
• must be tall and long with no openings;
• are most effective within 61 meters (200 feet) of a highway (usually the first row of homes);
• must be designed to be visually appealing;
• must be designed to preserve aesthetic values and scenic vistas;
• do not increase noise levels perceptibly on the opposite side of a highway; and
• substantially reduce noise levels for people living next to highways.

Keeping the Noise Down

A sound occurs when an ear senses pressure variations or vibrations in the air. Noise is unwanted sound. The brain relates a subjective element to a sound, and an individual reaction is formed. Numerous studies have indicated that the most pervasive sources of noise in our environment today are those associated with transportation. Highway traffic noise tends to be a dominant noise source in our urban, as well as rural, environment.

What are Noise Barriers?

Noise barriers are solid obstructions built between the highway and the homes along a highway. They do not completely block all noise they only reduce overall noise levels. Effective noise barriers typically reduce noise levels by 5 to 10 decibels (dB), cutting the loudness of traffic noise by as much as one half. For example, a barrier which achieves a 10-dB reduction can reduce the sound level of a typical tractor trailer pass-by to that of an automobile.

Barriers can be formed from earth mounds or "berms" along the road, from high, vertical walls, or from a combination of earth berms and walls. Earth berms have a very natural appearance and are usually attractive. They also reduce noise by approximately 3 dB more than vertical walls of the same height. However, earth berms can require a lot of land to construct, especially if they are very tall. Walls require less space, but they are usually limited to eight meters (25 feet) in height for structural and aesthetic reasons.

When Are Noise Barriers Required?

Noise barriers are not always required at locations where an absolute threshold is met. There is no "number standard" which requires the construction of a noise barrier. Federal requirements for noise barriers may be found in Title 23 of the U.S. Code of Federal Regulations, Part 772, "Procedures for Abatement of Highway Traffic Noise and Construction Noise."

The Federal Highway Administration noise regulations apply only to projects where a State transportation department has requested Federal funding for participation in the improvements. The State transportation department must determine if there will be traffic noise impacts, when a project is proposed for (1) the construction of a highway on new location or (2) the reconstruction of an existing highway to either significantly change the horizontal or vertical alignment or increase the number of through-traffic lanes. If the State transportation department identifies potential impacts, it must implement abatement measures, possibly including the construction of noise barriers, where reasonable and feasible.

Federal law and Federal Highway Administration regulations do not require State transportation departments to build noise barriers along existing highways where no other highway improvements are planned. They may voluntarily do so, but they are solely responsible for making this decision.

How Is a Noise Barrier Funded?

There are no special or separate Federal funds for highway traffic noise abatement. State transportation departments include the costs of noise barriers in their proposed Federal-aid highway projects. The Federal share is the same as that for the highway system on which the project is located. Noise barriers are sometimes constructed without using Federal funds - for example, using only State, local, or private funds. The costs of noise barriers are sometimes shared by governmental agencies and individual homeowners.

How Does a Noise Barrier Work?

Noise barriers reduce the sound which enters a community from a busy highway by either absorbing the sound, transmitting it, reflecting it back across the highway, or forcing it to take a longer path over and around the barrier. A noise barrier must be tall enough and long enough to block the view of a highway from the area that is to be protected, the "receiver." Noise barriers provide very little benefit for homes on a hillside overlooking a highway or for buildings which rise above the barrier. A noise barrier can achieve a 5 dB noise level reduction, when it is tall enough to break the line-of-sight from the highway to the home or receiver. After it breaks the line-of-sight, it can achieve approximately 1.5dB of additional noise level reduction for each meter of barrier height.

To effectively reduce the noise coming around its ends, a barrier should be at least eight times as long as the distance from the home or receiver to the barrier.

Openings in noise barriers for driveway connections or intersecting streets destroy their effectiveness. In some areas, homes are scattered too far apart to permit noise barriers to be built at a reasonable cost. Noise barriers are normally most effective in reducing noise for areas that are within approximately 61meters (200 feet) of a highway (usually the first row of homes).

What Type of Material Is Best for a Noise Barrier?

Noise barriers can be constructed from earth, concrete, masonry, wood, metal, and other materials. To effectively reduce sound transmission through the barrier, the material chosen must be rigid and sufficiently dense (at least 20 kilograms/square meter). All noise barrier material types are equally effective, acoustically, if they have this density.

There are no Federal requirements specifying the materials to be used in the construction of highway traffic noise barriers. Individual State departments of transportation select the materials when building these barriers. The selection is normally made based on factors, such as aesthetics, durability, maintenance, cost, and the desires of the public.

How Do People React to Noise Barriers?

Overall, public reaction to highway noise barriers appears to be positive. However, specific reactions vary widely. Residents adjacent to barriers say that conversations in households are easier, sleeping conditions are better, the environment is more relaxing, windows are opened more often, and yards are used more in the summer. Residents also perceive indirect benefits, such as increased privacy, cleaner air, improved views and a sense of ruralness, and healthier lawns and shrubs.

Negative reactions from residents have included a restriction of view, a feeling of confinement, a loss of air circulation, a loss of sunlight and lighting, and poor maintenance of the barrier. Motorists have sometimes complained of a loss of view or scenic vistas and a feeling of being "walled in" when traveling adjacent to barriers.

Are Residents' Views Considered?

A major consideration in the design of a noise barrier is its visual impact on the surrounding area. A tall barrier near a one-story, single family, detached residential area can have a negative visual effect. One solution to addressing the size relationship in visual quality is to provide staggered horizontal elements to a noise barrier to reduce the visual impact by planting landscaping in the foreground. Native plantings are preferable.

The visual character of noise barriers in relationship to their environmental setting should be carefully considered. In general, it is desirable to locate a noise barrier approximately four times its height from residences and to provide landscaping near the barrier to avoid visual dominance.

Noise barriers should reflect the character of their surroundings as much as possible. It is always desirable to preserve aesthetic views and scenic vistas, to the extent possible.

Are Motorists' Views Considered?

The psychological effect of noise barriers on the passing motorist should be a part of barrier design and construction. Noise barriers in dense, urban settings should be designed differently than barriers in more open suburban or rural areas, and they should be designed to avoid monotony for the motorist. At normal roadway speeds, motorists tend to notice noise barriers overall form, color, and surface texture. A primary objective of noise barrier design should be to avoid a tunnel effect for the motorist. This can be accomplished by varying the forms, materials, and surface treatments.

Graffiti on noise barriers can be a potential problem. One solution is to use materials that can be readily washed or repainted. Landscaping and plantings near barriers can also be used to discourage graffiti, as well as to add visual quality.

Does Construction of a Noise Barrier Increase Noise Levels on the Opposite Side of the Highway?

Residents adjacent to a highway sometimes feel that their noise levels have increased substantially, because of the construction of a noise barrier on the opposite side of the highway. However, field studies have shown that this is not true. If all the noise striking a noise barrier were reflected back to the other side of a highway, the increase would be theoretically limited to 3 dB. In practice, not all of the acoustical energy is reflected back to the other side. Some of the energy goes over the barrier, some is reflected to points other than the homes on the opposite side, some is scattered by ground coverings (for example, grass and shrubs), and some is blocked by the vehicles on the highway. Additionally, some of the reflected energy is lost due to the longer path that it must travel. Measurements made to quantify this reflective increase have never shown an increase of greater than 1-2 dB an increase that is not perceptible to the average human ear.

Does Construction of Noise Barriers on "Both" Sides of a Highway Increase Noise Levels?

Multiple reflections of noise between two parallel plane surfaces, such as noise barriers or retaining walls on both sides of a highway, can theoretically reduce the effectiveness of individual barriers. However, studies of this issue have found no problems associated with this type of reflective noise. Any measured increases in noise levels have been less than can be perceived by normal human hearing, that is, less than 3 dB. Studies have suggested that to avoid a reduction in the performance of parallel reflective noise barriers, the width-to-height ratio of the roadway section to the barriers should be at least 10:1. The width is the distance between the barriers, and the height is the average height of the barriers above the roadway. This means that two parallel barriers 3 meters (10 feet) tall should be at least 30 meters (100 feet) apart to avoid any reduction in effectiveness. These studies have also shown that any reduction in performance can be eliminated through the use of sound absorptive noise barriers.

Can Trees Be Planted to Act as Noise Barriers?

Vegetation, if it is high enough, wide enough, and dense enough that it cannot be seen over or through, can decrease highway traffic noise. A wide strip of trees with very thick undergrowth can lower noise levels. 30 meters of dense vegetation can reduce noise by five decibels. However, it is not feasible to plant enough trees and other vegetation along a highway to achieve such a reduction. Trees and other vegetation can be planted for psychological relief but not to physically lessen noise levels.

In Summary
 

Most residents near a barrier seem to feel that highway noise barriers effectively reduce traffic noise and that the benefits of barriers far outweigh the disadvantages of barriers. While noise barriers do not eliminate all highway traffic noise, they do reduce it substantially and improve the quality of life for people who live adjacent to busy highways.

A noise barrier is an exterior structure, designed to protect sensitive land uses from noise pollution. It is commonly also called a soundwall, sound berm, sound barrier and acoustical barrier. Noise barriers are the most effective method of roadway noise mitigation, and mitigation of railway and industrial noise sources (other than cessation of the source activity or use of source controls). In the case of surface transportation noise, very little can be done to further reduce the source noise intensity (other than increase the percentage of hybrid vehicles and electric vehicles, a strategy that works only at low to moderate traffic flow speeds). Extensive use of noise barriers began in the United States after noise regulations that were introduced in the early 1970s.

Noise barriers have been built intuitively, but infrequently, in the United States since the mid twentieth century, when vehicular traffic burgeoned; however, in the late 1960s acoustical science technology emerged to mathematically evaluate the efficacy of a noise barrier design adjacent to a specific roadway. Below, a researcher collects data to calibrate a roadway noise model for Foothill Expressway.

Acoustical scientist measures sound in Noise barrier design study, Santa Clara County, Calif.

The best of these early computer models considered the effects of roadway geometry, topography, vehicle volumes, vehicle speeds, truck mix, roadway surface type and micrometeorology. Several research groups within the U.S. developed variations of the computer modelling techniques: Caltrans Headquarters in Sacramento, California; the ESL inc. group in Palo Alto, California; the Bolt, Beranek and Newman^[1] group in Cambridge, Massachusetts and a research team at the University of Florida. Possibly the earliest published work that scientifically designed a specific noise barrier was the study for the Foothill Expressway in Los Altos, California^[2].

Rapidly following, there ensued numerous case studies across the U.S. addressing dozens of different existing and planned highways. These studies were commonly commissioned by State Highway Departments and were mostly conducted by one of the four research groups mentioned above. The U.S. National Environmental Policy Act^[3] had arrived and effectively mandated the quantitative analysis of noise pollution from every Federal-Aid Highway Act Project in the U.S., propelling noise barrier model development and application. With passage of the Noise Control Act of 1972^[4], demand for noise barrier design soared from a host of noise regulation spinoff.

By the late 1970s there were over a dozen research groups in the U.S. applying similar computer modelling technology and addressing at least 200 different locations a year for noise barriers. As of 2006, this technology is considered a standard in the evaluation of noise pollution from highways, but, remarkably, the nature and accuracy of the computer models used is nearly identical to the original 1970 versions of the technology.

The acoustical science of noise barrier design is a complex task based upon treating a roadway or railway as a line source. Firstly, the theory is based upon blockage of sound ray travel toward a particular receptor; however, diffraction of sound must be addressed. That is to say, sound waves bend (downward) when they pass an edge, such as the apex of a noise barrier. Further complicating matters is the phenomenon of refraction, the bending of sound rays in the presence of an inhomogeneous atmosphere. Wind shear and thermocline produce such inhomogeneities.

The sound sources modelled must include engine noise, tire noise and aerodynamic noise, all of which factors vary by vehicle type and speed. One can begin to visualize the complexity of the resulting computer model, which is based upon dozens of physics equations translated into thousands of lines of computer code.

Noise barrier earth berm along Highway 12, Sonoma County, California

Some noise barriers consist of a masonry wall or earthwork, or a combination thereof, such as a wall atop an earth berm. Sound abatement walls are commonly constructed using steel, concrete, masonry, wood, plastics, insulating wool, or composites. In the most extreme cases, the entire roadway is surrounded by a noise abatement structure, or dug into a tunnel using the cut-and-cover method. The noise barrier may either be constructed on private land or on a public right-of-way or other public land or other surface such as a marsh, public or private. Since sound levels are measured using a logarithmic scale, a reduction of nine decibels is equivalent to elimination of about 80 percent of the unwanted sound. The bottom line is that noise barriers can be extremely effective tools for noise pollution abatement, although theory also calculates that certain locations and topographies are not suitable for use of any reasonable noise barrier. Clearly cost and aesthetics play a role in the final choice of any noise barrier.

There are clear disadvantages of noise barriers, most prominently:

·      Aesthetic impacts for motorists and neighbors, particularly if scenic vistas are blocked.

·      Considerable costs of design, construction and maintenance.

·      Necessity to design custom drainage that the barrier may interrupt.

Normally the benefits of noise reduction far outweigh aesthetic impacts for residents protected from unwanted sound. These benefits include lessened sleep disturbance, improved ability to enjoy outdoor life, reduced speech interference, stress reduction, reduced risk of hearing impairment and reduction in blood pressure (improved cardiovascular health).

With regard to construction costs, a major factor is the availability of excess soil in the immediate area which could be used for berm construction. If the soil is present, it is often cheaper to construct an earth berm noise barrier than to haul away the excess dirt, provided there is sufficient land area available for berm construction. Generally a four to one ratio of berm cross sectional width to height is required. Thus, for example, to build a six foot high berm, one needs an available width of 24 feet.

Earth berm noise barriers can be constructed solely of excess earth from grading pads for a residential development it will protect. Thus its entire construction cost is negligible; arguably, it may pay into the project, since offhaul of earth may have been needed. A further nuance of this particular project is that the residential side of the berm is overexcavated, which gives more privacy between highway and homes and also enhances noise benefit. Finally, note the aesthetics of the earth berm which blends with scenic elements of the natural hills of Annadel State Park in the background. It may be a surprise to find out this berm is over six feet in height, since the aesthetics of earth mounding reduce the visual impact of the structure, compared to a soundwall.

As a minor embellishment to noise barrier design, one may note the concept of constructing a louver or cap atop the wall that is directed back toward the noise source. This concept follows the theory that such a design should inhibit shadow zone diffraction filling in sound behind the noise barrier. In actual experience the benefits are slight compared to the benefits of a higher barrier and the costly construction techniques necessary to create and maintain such a device. Variation of the louver design can be found in Denmark, where the designs are also intended to minimize reflected sound. Furthermore some of the Danish soundwalls are made of transparent materials to minimize the visual impact; such material use, however, compromises the efficacy by reducing mass.

We're getting the dBA down

[ Home ] [ Up ]

Copyright © 2007 ArtUSA Noise Control Products Inc.

We manufacture sell, and install: Noise Control Enclosures, Sound Enclosures, Acoustical Materials, Equipment Enclosures, Personnel Enclosures, Sound Barrier Walls, Portable Screens, Thermal Enclosures, Noise Barrier Walls, Audiometric Testing Booths and Rooms, Punch Press Enclosures, engine Test Cells, Clean Rooms, Diesel Generator Enclosures, Positive Displacement Enclosures, Fiberglass Enclosures In-plant Space, Attenuators, Silencers, Rectangular Silencers, Round Silencers, Elbow Silencers,- - - We Package sell and install, Sanitary Panels and Baffles, Damping Compound, Curtain Enclosures, Acoustical Pipe Lagging, Duct Lagging, Industrial Ceiling Baffles, Class 1 Fire Rated Acoustical Foam, Polyurethane Sound Foam, Fiber-Free Noise Control Foam, Adhesive Backed Absorbing Foam, Noise Control Facings and Barriers, SONEX, Sound Seal, Acoustical Curtains, Acoustical Foam. We provide: Noise Control Solutions, Noise Abatement - Fabric and Decorative Foam Panels, Sound Baffles, Sound Deflectors - Sound Curtains, Banners, Dosimeters, Calibrators Real Time Analyzers, Software, Active Noise Canceling Ear Muffs, Noiseless Metals, Dust Collectors, Fume Oxidizers, Oil Mist Collectors, Smoke Capture, Work Stations, Isolation Mounts, Pads - Levelers. we sell and install Architectural Noise Control Products and Solutions.