As people seek to be closer to loud but job-rich city centers or noisy transportation hubs such as freeways and train stations to ease commute times and lower fuel costs, reducing noise pollution has become increasingly important.
- The Environmental Protection Agency (EPA) reports, noise pollution negatively impacts millions of people leading to stress-related illnesses and greatly impacts the ability to concentrate or listen effectively.
- According to the CDC, noise above 70 decibels over a long period of time can cause hearing damage. City traffic has been documented to reach a continuous level of 85 decibels, which has been linked to health problems, including heart disease and mental illness.
One of the ways to reduce noise pollution is by choosing the right acoustic windows for buildings located in areas with prolonged noise exposure. The Construction Specifier magazine recently discussed this issue of noise pollution and acoustics:
City Responses to Noise
Noise reduction programs have been implemented near large airports. In Chicago, the O’Hare Residential Sound Insulation Program (RSIP) addresses the impact of noise in homes while the O’Hare School Sound Insulation Program (SSIP) addresses noise levels in nearby schools. Both programs are designed to mitigate the impact of airport noise on existing buildings by incorporating acoustical insulation batts in ceilings, replacing HVAC systems, and installing acoustic windows and doors.
Urban noise from construction, air-conditioners, rooftop circulation devices, food trucks, sanitation vehicles, and dense city traffic cause noise levels higher than is considered safe for public health. The New York City Department of Environmental Protection (DEP) created the NYC Noise Code to restrict decibel levels of ‘city noise’ impacting personal comfort and safety. Construction sites are now required to have a noise mitigation plan before work begins and vehicle horns use is illegal, except as a warning of imminent danger.
Sound Transmission STC versus OITC
Understanding acoustic ratings and desired outcomes are key for selecting products. While both Sound Transmission Class (STC) and Outdoor-Indoor Transmission Class (OITC) are sound ratings; they are two different measurements. STC measures sound transmission from room to room and OITC measures sound transferred from outside to inside. Both are effective, but STC rating is most often be used for offices, hotel rooms, or condo units, while OITC is used for buildings near busy transportation hubs or heavy urban traffic noise.
Additionally, it is important to understand the noise frequency. Air traffic has a lower frequency while train/subway noise has a higher frequency. Products with high STC or OITC ratings may not be effective with specific frequencies. Third-party independent product test results are a great way to evaluate the entire sound spectrum, at multiple frequencies.
How to Best Block Noise
For windows, acoustic performance is directly related to the type of glass and fenestration design.
Heavier, thicker laminated glass, and as well as high-impact glass have better sound-dampening qualities. The high-performance panels in the interior wall of the framing system also significantly dampen the sound waves. Both of which can improve an STC and/or OITC rating by eight to 10 points.
Framing design and glass sealing methods also impact performance. Polyvinyl butyral (PVB) interlayers used at 1.5 mm (0.060 in.) can provide better performance.
Cost-Effective Acoustic Considerations
It is beneficial to collaborate early with fenestration product manufacturers and acoustics specialists. Although high-performance acoustic windows may be more expensive initially, the cost of replacing or retrofitting for acoustics is higher.
“The failure to budget for acoustics can also lead to additional unforeseen expenses. For example, when building a hotel near a busy street, airport, railway, music venue, or other noisy environments, acoustics will be of utmost importance for guest comfort and for business to thrive.”
For some projects, only part of a building may be impacted by noise. In these instances, it is beneficial to understand the type and frequency of exterior noise because this allows for cost-effective planning for each side of the building.
Acoustic windows reduce the amount of outside noise that seeps into buildings. Look for STC and OITC ratings to find the optimal levels of noise mitigation. Our acoustic window experts at St. Cloud window can help you find the best window for your needs – request a quote today for more information.
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