How to Sound Insulate Windows from Noise?
STC or OITC, what rating do you even need?
How to insulate windows from noise?
Throughout the years, many different options have run the market when it comes to acoustic windows, from heavy laminated glass, triple pane windows, thicker spacers, etc. After years and years of testing data, we have found an option that gets you the performance you need without breaking the bank or breaking the backs of workers who have to lift windows during installation.
What we have found is that the best option is to vary the individual lite thickness of the glass within an IGU, as well as varying the air space. By changing the thickness of the glass, the sound waves will have to modify to move through the glass. Adding more air space also means the sound waves have more space to move through and dissipate as they go.
Sound performance has been measured in two ways for years, as shown below:
Do you know the difference between STC and OITC, and why are there two?
STC stands for Sound Transmission Class and is a rating of how well a building partition reduces airborne sound. This rating evaluates how well the windows block internal noises such as conversations, television, or typing, generally ranging from 125 to 4000 Hz.
OITC stands for Outdoor-Indoor Transmission Class and is a rating of the amount of sound that passes between the interior and exterior spaces in a structure. It tests a wider range, 80 to 4000 Hz, to assess how well the windows block external noises like train whistles, street noise, or air traffic.
STC has been around since 1961 and was the standard for rating window acoustics for a long time. The OITC measurement was introduced in 1990 to assess outdoor noise more accurately. As a result, OITC is the ideal measurement for assessing the acoustic performance of windows, and the higher the OITC rating, the less sound will travel through the window.
Typically, highway noise has an OITC rating of 20-27, downtown congestion and trains generally are 27-35, and aircraft is OITC 35 and higher, depending on proximity to the airport. Understanding these ratings helps you choose the right window based on your environment.
Now we are back to the why?
Did you know exposure to high levels of noise or repeated exposure to noise can lead to permanent hearing loss or raised blood pressure leading to cardiovascular damage? Sound-insulating windows can play a critical role in protecting human health by significantly reducing noise exposure. Take a listen to this video and hear how much of an impact an 18-decibel difference can make.
Regardless of the building type, the health of human occupants needs to be considered long term. Imagine working or living in a space where exterior noise continuously disrupts your focus. If you own a building, poor acoustic ratings could lead to high tenant turnover or unfilled spaces. Acoustical performance should be a consideration in every window purchase.
Want to know more about our acoustic glass packages that offer great performance without the high costs of fancy laminated glass? Fill out our RFQ with any questions you have.
