Building acoustics refers to any number of acoustical issues that affect buildings including sound isolation, reverberation control, HVAC noise control, and impact noise. Acoustics are critical for auditoriums, churches, and recording studios but are also important for many other building situations. DCC can perform acoustical measurements, determine problem areas, and recommend solutions for a variety of buildings and uses.
Sound isolation generally refers to the acoustical separation between spaces. For example, a home near an airport should have substantial outdoor to indoor noise reduction to allow for proper speech communication and undisturbed sleep. Multi-unit apartment buildings should have enough sound isolation between units so that neighbors do not disturb each other.
Excessive reverberation (echoes) in spaces with hard surfaces can result in poor speech intelligibility or can ruin certain types of musical performances (such as rhythmic contemporary music). Conversely, long reverberation time in an auditorium can enhance symphonic music.
HVAC Noise Control
Heating, ventilation, and air conditioning noise can be problematic in a variety of building situations. DCC can recommend appropriate duct silencers and vibration isolators for HVAC systems.
Impact Noise Control
Impact noise can occur in multi-dwelling apartments where footfall noise can be clearly heard in the unit below. Impact noise can be measured and assessed with standardized techniques. DCC can recommend floor treatments to meet appropriate Impact Isolation Class (IIC) standards.
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Environmental noise can be caused by a wide variety of sources such as transportation (highway, rail, aircraft), industrial, and recreational facilities (race tracks, amphitheaters). DCC can measure, model, and assess environmental noise and recommend mitigation where necessary.
Environmental Noise Measurements
DCC can measure environmental noise according to standards developed by agencies that have jurisdiction over the noise sources. Such standards can employ metrics such as the Day-Night Average Noise Level (DNL), a 24-hour average with a 10 decibel penalty for nighttime noise--to account for peoples' increased sensitivity to noise at night. Short term noise measurements might be appropriate in certain situations. For example, several noise sources might affect a particular location and the contribution of each source to the total noise level might be required in order to recommend the most efficient mitigation. This can be accomplished by short term noise measurements taken close to each source.
DCC employs a wide variety of noise models to address the breadth of environmental noise situations that can occur. For example, agencies that oversee highway, aircraft, and rail transportation systems have developed computer models to predict noise levels associated with a particular scenario. In addition, these computer models can be used to accurately predict the amount of attenuation provided by various mitigation measures such as noise barriers. DCC is experienced with a wide array of such models.
Vibration can be an issue for certain transportation systems, such as rail transportation, and can also be a major issue in buildings. DCC has in-depth experience measuring and assessing vibration as well as recommending vibration control measures.
DCC has performed vibration measurements for light and heavy rail systems in order to determine compliance with annoyance and building damage standards. DCC also has performed a wide variety of vibration measurements in buildings, laboratories, and spaces with vibration-sensitive equipment.
Vibration control refers to any mechanism that reduces vibration at the source, along the vibration path, or at the receiver location. DCC has recommended and implemented a wide variety of vibration control measures such as ballast mats for train systems, vibration isolators for HVAC units, damping material for vibrating surfaces, and floating slabs for vibrating equipment.
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