Take a good look at our STC and NRC ratings
Industry-leading sound mitigation
There are two ways to measure a sound barrier’s performance – Noise Reduction Coefficient (NRC) and Sound Transmission Class (STC). NRC measures the volume of sound absorbed versus the volume reflected, while STC measures the volume of sound that the wall allows to pass through. As shown below, all our sound wall products meet and surpass recommended NRC and STC standards.
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Product Specifications |
Silent Protector® (Absorptive) |
Tuf Barrier® (Reflective) |
Span1 |
8 ft -12 ft (2.44 m – 3.66 m) |
8 ft -14 ft (2.44 m – 4.27 m) |
Panel Width |
2.70 in (68.58 mm) |
2.70 in (68.58 mm) |
Panel Height |
5.96 in ± .10 in |
5.96 in ± .10 in |
Weight |
4.30 lbs/ft2 (21 kg/m2)4 |
Min. 4.10 lbs/ft2 (20 kg/m2) |
Wall Height |
Greater than 30’/ 9 m |
Greater than 30’/ 9 m |
STC Rating |
up to 39 |
31 |
NRC Rating |
0.95 |
n/a |
- Span is governed by wind loads and varies on code requirements. Contact AIL Sound Walls for recommended panel spans for your project.
- Standard Silent Protector has an STC rating of 32. Silent Protector Plus can achieve STC of 39.
- Standard Silent Protector NRC 0.95. Silent Protector Plus NRC is 0.90.
- Weight of Silent Protector Plus is 7.30 lbs/ft2 (36kg/m2)
Sound Transmission Loss ASTM E90 / E413
Octave Band Number |
2 |
3 |
4 |
5 |
6 |
7 |
STC |
Center Frequency (Hz) |
125 |
250 |
500 |
1000 |
2000 |
4000 |
– |
Silent Protector ® |
23 |
21 |
28 |
42 |
48 |
49 |
|
Silent Protector ® Plus |
30 |
28 |
34 |
43 |
45 |
49 |
|
Tuf-Barrier ® |
23 |
19 |
30 |
45 |
45 |
54 |
Sound Absorption Coefficients ASTM C423/E795
Octave Band Number |
2 |
3 |
4 |
5 |
6 |
7 |
NRC |
Center Frequency (Hz) |
125 |
250 |
500 |
1000 |
2000 |
4000 |
– |
Silent Protector ® |
0.29 |
0.80 |
1.13 |
1.00 |
0.96 |
0.72 |
0.95 |
Silent Protector ® Plus |
0.28 |
0.71 |
1.06 |
0.97 |
0.94 |
0.78 |
0.90 |
STC – Sound Transmission Class
STC is an integer rating used to measure the decibel reduction through a partition. It states the number of decibels lost through that partition in a laboratory environment.
NRC – Noise Reduction Coefficient
NRC is a rating between 0 and 1 to index how absorptive a material is. An NRC of 0 means no sound waves are absorbed whereas a rating of 1 means all of the sound waves are absorbed.
NRC |
Qualitative |
0.4 or less |
Poor |
0.5 to 0.6 |
Mediocre |
0.6 to 0.7 |
Good |
0.7 to 0.85 |
Very Good |
> 0.85 |
Excellent |
0.95 |
AIL Silent Protector® |