Understanding STC Ratings

Whether you live or work in a bustling city or suburban area, noise is a constant. And, as our population continues to grow, the spaces we inhabit are only getting noisier. Adapting to the constant chorus horns honking, trains screeching, and dogs barking often requires a bit of outside help to dampen the disruptive nature of these sounds that can have a serious impact on our health and quality of life.

One common method to battle persistent external noise is the use of soundproofing products to minimize and even eliminate unwanted sound. However, a quick search on the internet for soundproofing systems will bring you thousands of options from brands across price ranges. So just how can you tell which product will work the best? Enter the STC Rating, a universal system for determining the soundproofing capabilities of a given product.

What Does STC Stand for?

So, what is STC, and what does STC mean? STC stands for Sound Transmission Class and is a useful tool for anyone wondering how much sound a certain product can reduce and at which frequencies. Simply put, an STC rating gives you a general idea of how much sound a barrier, such as a window or door, can stop. The STC rating is the most commonly used method for measuring the sound reduction capabilities of a product and is therefore trusted by customers in the market for soundproofing products.

Which Barriers Receive an STC Rating?

As the most commonly used measurement of sound reduction in use today, the STC rating is a reliable source of information for a variety of barriers. In fact, partitions including doors, floors, and ceilings are all available. Most often, however, individuals looking to soundproof their home or work spaces are interested in the STC rating for walls and STC rating for windows.

Understanding STC Sound

Still asking yourself, “What is STC rating? And how does it work?” To dig deeper into STC and how this rating works, you first need to understand how we measure sound: frequency, decibel, and transmission loss.

Frequency: The frequency of a sound measures the musical note or tone of the sound. The unit hertz (Hz) is used to measure frequency and is the number of soundwaves that pass by per second. A low frequency sound, such as a man’s deep voice, will contrast greatly with a high frequency sound, like the noise of a flute. Humans are only capable of registering frequencies between 20Hz and 20,000 Hz, and this range changes as we age.

Decibels (dB): In short, decibels are the measurement of how loud something is. On the Sound Pressure Scale, 0dB marking the threshold for audability. Uncomfortably loud noises, such as those that cause pain and even injury to the ear, will register at around 130 dB.

Transmission Loss: Transmission loss measures the the volume difference (dB) on either side of barrier, such as a window or wall. For example, if someone sits one side of a wall watching television at a noise level of 100 dB, and you stand on the other side of the wall where the noise level is recorded at 75 dB. There exists a transmission loss of 25 dB.

STC Rating Calculator

If you’re shopping for sound-resistant products, understanding how ratings are calculated for STC rated doors, windows and other barriers can be useful to more easily compare and weigh options. To determine the STC windows, doors and other barriers have, testing is done using 16 standard frequencies across the range of 125 Hz and 4000 Hz, measuring the transmission loss values, plotting these values on a graph. The curve created is then compared to the standard STC reference curves. If the curve plotted on the graph for a wall is most similar to a standard STC 50 curve, for example, using the STC wall rating calculator your wall is assigned an STC rating of 50. In general, the higher the STC rating of a material or product, the more effective it is in reducing and blocking out sound at frequencies most commonly encountered on a daily basis.

Window STC Rating Chart

A typical STC rating chart will often include an example of materials with a given STC rating, and the sounds you can expect to hear given the STC rating. An example of a window STC rating chart is as follows:

  • 26-28 – single pane window
  • 26-32 – double pane window
  • 48-54 – soundproof window over a single pane window
  • 48-54 – soundproof window over a dual pane window

In addition to windows STC rating charts, there exist STC wall rating charts, STC door rating charts, and more, depending on the specific product you’re looking for.

STC Ratings and Soundproof Windows

Ultimately, STC ratings make it easier for individuals and families to create tranquil spaces to live and work. One great option to do so is through the installation of soundproof windows. Customers across the country trust CitiQuiet to provide top quality soundproof windows for their houses and office spaces. Better yet, CitiQuiet soundproof windows have some of the highest STC rated windows, so you know you’re installing a product that will keep the noise out. In fact, CitiQuiet windows are effective in removing up to 95% of outside noise. Contact a CitiQuiet representative today to learn about the quality soundproof window options available to you that span across a wide range of STC ratings, so you’re sure to find the noise reducing product at the level that fits your specific needs.

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