CONCRETE SOUND WALLS

History of Sound Walls

Sound wall barriers, also known as sound walls, noise barriers,acoustical barriers and sound berms, are designed to protect the public against noise pollution. Noise pollution is adverse sound level exposure that can lead to hearing loss, sleep disturbance, stress and increased blood pressure.

To decrease noise pollution effects, government noise regulation mandates such as the U.S. National Environmental Policy Act, Federal-Aid Highway Act and Noise Control Act of 1972 have been instituted. These Acts promote decreased noise pollution, quantitative noise analyses, sound wall barrier use and city noise planning. These laws had a significant impact on the housing, city planning and transporting industries from the late 1960s through the early 1980s, when Federal funding for noise pollution was stopped.

Sound Wall Technology: STC Ratings

Sound wall barriers are constructed from earth, masonry or precast concrete. Sometimes a combination of these materials is used. When sound wall barriers are constructed, they are built on approved land sites such as on privately owned land approved by the owner, or on public right-of-way land areas approved by those with the proper jurisdiction.

To determine if sound wall barriers are effective, scientists gauge the sound allowed to pass through or over the wall. These outdoor structures, designed to block the passage of sound travel, are tested using a logarithmic scale and given an STC (Sound Transmission Class) Rating. STC Ratings are dependent on a variety of factors, such as materials used, thickness and density of the materials, finished surface preparation, the weight of the wall per square foot of surface area, gaps, voids and seams in the construction. When a nine decibel reduction is reached, a sound wall barrier is considered adequate. Nine decibels lower in sound is equal to approximately a 90 percent drop in sound waves traveling past the wall. STC ratings for partition materials may range from 40 to more than 60, with higher values providing lower sound transmission. The Federal Housing Administration (FHA) requires a minimum STC of 46 to limit sound transmission from unit to unit in multi-family dwellings.

AFTEC (link to AFTEC Site) has recently designed and developed SoundTec™ Wall Systems , an effective and efficient Precast Concrete sound wall barrier manufactured with AFTEC’s Sound Wall Forming Equipment. SoundTec™ Sound Wall panels effectively intercept and deflect noise levels up to 10 decibels, mitigating traffic noise. They are also durable to weather and other conditions, and are aesthetically pleasing because the wall panels have a highly defined formed texture on both sides of the wall.

During sound wall panel construction, it is important to make sure that the sound wall panels do not have voids, seams or cracks through which sound can pass. The full height panel construction, as formed in AFTEC’s SoundTec™ Wall Forming System eliminates the possibility of sound escaping through the seams of stacked panels.

The benefits of using AFTEC’s SoundTec™ Highway Sound Wall Barrier System are…

• Capable of producing 2,200 sq. ft. of wall per casting
• Adjustable bulkheads for multiple sizes of panels
• Various sizes of panels can be cast at the same time
• Designed to cast sound walls of various thickness
• Highly defined formed texture on both sides of the sound wall provide community acceptance and helps in negotiating right of ways
• Form liners are interchangeable for different designs
• On site production capabilities
• Maximum efficiency in all phases of production