Take a good look at our STC and NRC ratings
Industry-leading sound mitigation
There are two ways to measure a sound wall’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.
Product Specifications |
Silent Protector® (Absorptive) |
Tuf Barrier® (Reflective) |
Span1 |
8 ft -16 ft (2.44 m -4.87 m)2 |
8 ft -16 ft (2.44 m -4.87 m)2 |
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)3 |
Min. 4.10 lbs/ft2 (20 kg/m2)4 |
Wall Height |
Greater than 30 ft / 9 m |
Greater than 30 ft / 9 m |
STC Rating |
up to 395 |
up to 366 |
NRC Rating |
0.957 |
n/a |
- Span is governed by wind loads and varies on code requirements. Contact AIL Sound Walls for recommended panel spans for your project.
- Achieve spans of up to 16 ft (4.88 m) with Silent Protector XL® or Tuf-Barrier XL®.
- Weight of Silent Protector Plus® is 7.3 lbs/ft2 (36 kg/m2).
- Weight of Tuf-Barrier Plus® is 7.5 lbs/ft2 (36.5 kg/m2).
- Standard Silent Protector® has an STC rating of 32. Silent Protector Plus® can achieve an STC rating of 39.
- Standard Tuf-Barrier® has an STC rating of 31. Tuf-Barrier Plus® can achieve an STC rating of 36.
- Standard Silent Protector® NRC is 0.95. Silent Protector Plus® NRC is 0.90.
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 |
32 |
Silent Protector Plus® |
30 |
28 |
34 |
43 |
45 |
49 |
39 |
Tuf-Barrier ® |
23 |
19 |
30 |
45 |
45 |
54 |
31 |
Tuf-Barrier Plus® |
24 |
21 |
36 |
45 |
49 |
57 |
36 |
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® |