If you have bought any soundproofing material or searched for one, you would have come across many products claiming to have an NRC rating of 0.80, 0.90, etc. Here I will explain what NRC is and what it means.
What does NRC stand for?
NRC stands for Noise Reduction Coefficient.
What is NRC range?
The NRC rating ranges from 0 to 1. It is a standard for determining the ability of a product to absorb sound. This rating tells us how much of the noise a product will dampen and how much of it would be reflected.
NRC rating only covers the frequency range of 250 Hz, 500 Hz, 1000 Hz, and 2000 Hz. It doesn’t take the performance of sounds below or above those four frequencies.
What is a good NRC rating?
The NRC rating of 0 implies that the material won’t absorb any noise. While a score of 1 signifies that this material won’t reflect any sound and is capable of fully absorbing the noise.
If you see a soundproofing material with a score of 0.5, that means it can absorb 50 percent of the sound and is 50% reflective. Every product present in the market has an NRC rating. Most of the companies don’t put them in the label as this rating is perceived to be only used for acoustic products.
If you are looking to buy a soundproofing material, then a substance with NRC greater than 0.65 is considered good.
Some materials are very good at absorbing the noise while others are abysmal at this job. For example, polished marble floors have meager NRC rating between .01-.05, and they are the worst sound dampening material. On the other hand a 2″-3″ thick fiberglass scores between 0.90-0.98. Even though this helps in comparing materials, it isn’t that much of a help in deciding the materials for soundproofing.
The table below elaborates what rating is considered great.
| NRC | Qualitative |
|---|---|
| 0.40 or less | Poor |
| 0.41 to 0.60 | Mediocre |
| 0.61 to 0.70 | Good |
| 0.71 to 0.85 | Very Good |
| Greater than 0.85 | Excellent |
This table will help you in understanding the ratings.
What material absorbs sound waves the best?
As we have already discussed not all the materials have the same ability to absorb the noise. So, which one is the best material? The sound dampening performance of a material is based upon the density and thickness of a material. Any insulating material such as blankets or carpeting works well for absorbing sound waves.
Below are some materials that have great NRC rating.
| Material | NRC Rating |
|---|---|
| Concrete | .35 – .7 |
| Acoustic panel (1”) | .80 – 95 |
| Acoustic panel (2”) | .95 – 1.2 |
| Mineral Fiber Ceiling Tile | Up to .95 |
| Fiberglass | .75 |
If you are wondering that is there a typo in NRC rating of 2″ thick asoutic panel? The answer is no. Even though the best rating should be 1 but due to all the materials having 3 dimensions they sometimes perform even better than the best rating.
Some of the common products with good NRC rating are mentioned below.
- Foam panels
- Soundproof blankets
- Soundproof curtains or thick drapes. Find more about them here.
- Large pieces of furniture
- Acoustic panels
- Mass loaded vinyl
What materials absorb sound the worst
You should stay away from some materials if you are planning to soundproof your room or home. Below are some materials with very low noise reduction coefficient ratings:
| Material | NRC Rating |
|---|---|
| Sheetrock | .005 |
| Drywall | .05 |
| Gypsum | .06 |
| Wood | .15 |
| Plywood | .23 |
| Steel | .1 |
| Glass | .02 |
Why are products designed for NRC?
Due to the rising demand for the products required to soundproof the home, cars, dog crates, etc this rating will help in comparing and selecting the more suitable product.
This rating is not only used for soundproofing, but some industries also use this rating to decide which materials will be good for absorbing the echoes and make it possible to hear another person more clearly. You can observe that in many crowded places, construction sites or gym it is very hard to decipher what someone is saying.
Products with high NRC displays a higher soundproof quality. This is essential information for the consumer, which can help them make a decision regarding whether or not to purchase the product.
Conclusion
NRC rating (Noise Reduction Coefficient) is basically a scale from 0 to 1, describing the ability of a material to absorb the sound, with 1 being the best. The NRC of 0.7 means it can absorb 70 percent of the noise. Any material rated above 0.65 is good for soundproofing. This rating is frequently used soundproofing materials like foam.
If you are thinking about soundproofing your room than this guide will help you.