Turning down the sound on environmental noise
The impact of environmental noise like construction, traffic, and even weather is an important, though often forgotten, part of the design process. At Henderson Engineers, we have a team of dedicated acoustics professionals who recognize the impacts of environmental noise and help our clients achieve comfortable sound levels in their buildings. We’ve compiled some general information to help you understand how environmental noise impacts your space.
What is environmental noise?
Environmental noise is external, unwanted sounds that not only impact the comfort and enjoyment of the outdoors, but also heighten stress levels, disturb sleep, and even, in extreme cases, endanger your hearing. Some examples are:
• Transportation Noise (planes, trains, boats, truck traffic, highways, helicopter)
• Industrial Noise (manufacturing, utility, material handling, logistics/storage, wind farms)
• Construction Noise (heavy equipment, excavating, pile-driving, cranes, back-up alarms)
• Recreational Noise (amphitheaters, sports venues, event venues, restaurants, dog parks)
• Commercial Noise (rooftop equipment, air handling units, chillers, exhaust fans, generators)
Are there environmental noise standards?
Almost every town, city, and/or county has some kind of noise ordinance. These regulations commonly specify a sound level limit at adjacent property lines. Some can be difficult to understand or even have seemingly contradictory language; others are extremely detailed about site selection, barrier design, and architectural elements. During design, we help our clients determine their jurisdiction’s specific noise code requirements and what steps they need to take to comply.
How do I reduce environmental noise?
Decreasing noise levels benefits human health, satisfaction, and productivity. To address environmental noise concerns, studies are conducted outdoors using a sound level meter. The meter can also count excessive sound levels, identify specific octave signatures, and even save audio recordings of specific events, such as an aircraft flyover or train passing by. It can be placed in a weatherproof enclosure with a long-term battery pack so that testing can last a few minutes, multiple weeks, or even months depending what the study is trying to identify.
At this point, we can work with project teams to develop custom noise-reducing solutions based on space use, occupant expectations, and any relevant standards such as, HUD, FGI, LEED, FTA, or CALGreen. Environmental noise analysis is important for all projects especially workplaces, schools, hospitals, and multi-family housing. Our detailed environmental noise control recommendations can include:
Site and Location Selection
Sound levels decrease as distance increases. During the site planning process, it’s important to locate the building as far away as possible from a known noise source, such as highways or busy streets.
Building Massing and Orientation
Sound reflects off hard surfaces and can often amplify when it does. That means the shape, size, placement, and façade of buildings all factor into environmental noise. Understanding how these elements influence sound, and considering orientation and massing early on, can be a cost-effective way to address noise issues.
Exterior Noise Barriers
Like the concept of blocking light with a shade, the goal of a noise barrier is to block the sound between a source and receiver. A barrier can be constructed with a variety of materials like exterior-grade plywood, sheet metal, cement board, or concrete. However, pre-existing site features such as hills, earth berms, outbuildings, and other topography can also be effective noise barriers.
Architectural Design (Roof, Walls, Windows, Doors, Balconies)
The building façade can be used to mitigate exterior noise. Laminated-insulated windows, heavy duty weather-stripping, slate roof shingles, and stucco on lathe are examples of common building elements that are an effective upgrade for noise control over conventional, lightweight building façade materials.
Once the environmental noise study data is obtained and noise ordinance criteria is determined, we can design/engineer acoustic solutions. These solutions can be fine-tuned to the desired interior environment and architectural aesthetic preferences to make sure the noise ordinance is achieved. As your acoustics consultant, we work closely with your design team to determine practical, cost-effective sound isolation or noise mitigation solutions for your project.
Environmental noise studies can help you create a healthier environment and make informed decisions about your building. If you are experiencing issues with environmental noise, we can help. Contact us here for more information.