Measure and Manage Unwanted Sound

09/28/2021

“If silence is golden, good acoustics may be priceless.”

The acoustics of any space has a major impact on the well-being of the people inside. Continuous exposure to noise tends to cause irritability, sleeplessness, and stress, resulting in lower productivity. Thoughtful design of commercial buildings can have a significant impact on overall health, communication, and productivity.

The Construction Specifier recently shared how sound is measured and tactics for managing unwanted sound.

Sound is vibrations

Sound is created when something vibrates. The vibration causes the medium (water, air, etc.) around it to vibrate. The vibration or sound will then bounce off surfaces or transmit through the medium until its energy is exhausted.

Sound is measured

Sound transmission is measured in several ways. These numbers are best used as comparison tools.

Sound transmission class (STC) assesses the system’s ability to block sound and is a single-number rating of how much sound transmits from one room through a partition and into another room. It is assigned only to specimens tested in a laboratory. The higher the number, the better the noise attenuation.

Outdoor-Indoor Transmission Class (OITC) assesses the system’s ability to block sound outside the building and is a single-number rating for exterior walls, windows,  and doors that are subjected to transportation noises and other low-to-mid frequency noise sources. It is assigned to specimens tested in the field and in the laboratory. Also the higher the number, the better the noise attenuation.

Impact Isolation Class (IIC) provides an assessment of a system’s ability to resist transmitting impact sound from a space above to an area below. Again, the higher the rating the less noise is transmitted.

Noise Reduction Coefficient (NRC) indicates the ability of a material to absorb sound. The higher the NRC, the more absorptive the material.

Managing sound

Sound like water will find the path of least resistance. When sound finds its way around walls, windows, and floors, it’s called flanking noise. There are four basic strategies for managing flanking noise.

Absorb – Materials are used to absorb the acoustic energy of the sound wave and can be both structural materials as well as furnishings and fixtures.

Block – Physical barrier is used to stop the acoustic energy. This approach is used in wall, window, and floor design.

Break – Physical disconnection between vibrating components is created so the sound wave cannot travel between them. In windows, the thermal barrier between the structural frame and sash components physically breaks the connection between the two components.

Isolate – Isolation enables one area to vibrate without that energy traveling to the adjacent spaces. In floors, soundproofing clips are used to absorb the vibration from walking, which prevents the impact on the story above.

While tactics to managing flanking noise exist, it is important to start with upfront planning and specifying the products and materials during the design stage. Not sure what the right solution is for your project? St. Cloud Window has an expert team of product design specialists, engineers, and project management professionals dedicated to helping you realize your vision. Contact us today.