About STC and Rw Ratings
STC (Sound Transmission Class) is defined by ASTM E413 and used primarily in North America. Laboratory testing follows ASTM E90.
Rw (Weighted Sound Reduction Index) is defined by ISO 717-1 and used internationally. Laboratory testing follows ISO 10140-2.
STC and Rw are not directly interchangeable — they use different reference curves and test conditions. NEUWALL NW840-W has achieved STC 55 per ASTM E90 (report XMIN180500970CCM). Other models are rated under ISO 717-1 (Rw). Contact us if your project requires STC-rated products.
Understanding Acoustics
STC Acoustic Guide
Sound Transmission Class (STC) is a rating system defined by ASTM E413 to measure the ability of a partition to reduce sound transmission. The higher the STC rating, the better the acoustic isolation.
Outside North America, the equivalent metric is Rw, rated per ISO 717-1. NEUWALL products are tested and rated using the Rw standard (ISO 717-1) in HOKLAS-accredited laboratories. NEUWALL NW840-W has achieved STC 55 per ASTM E90 (report XMIN180500970CCM).
Understanding acoustic ratings helps you choose the right partition for your specific needs, whether it's a basic office divider or a high-security conference room.
STC Ratings Explained
Understanding Privacy Levels
Basic Privacy
Loud speech can be heard. Suitable for storage rooms and non-critical spaces.
Typical Applications:
Normal Privacy
Loud speech can be heard but not understood. Good for basic office separation.
Typical Applications:
Good Privacy
Loud speech is audible only as a murmur. Suitable for most commercial applications.
Typical Applications:
High Privacy
Loud speech is not audible. Excellent for confidential discussions.
Typical Applications:
Superior Privacy
Shouted speech is not audible. Ideal for sensitive environments.
Typical Applications:
Maximum Privacy
Even loud sounds are barely audible. Perfect for critical acoustic environments.
Typical Applications:
Common Noise Levels
Noise Reference Guide
Understanding common noise levels helps you determine the appropriate STC rating for your space.
Our Products
NEUWALL Acoustic Ratings (ISO 717-1)
| Model | Rw Rating | Type | Thickness |
|---|---|---|---|
| NW831 | Rw 40 / 43 / 45 dB | Single Panel | 80 mm (3-1/8 in) |
| NW840 | Rw 45 / 48 / 50 dB | Folding | 100 mm (3-15/16 in) |
| NW840-W | Rw 50 / 53 / 55 dB | Ultra-High | 92 mm (3-5/8 in) |
| NG840 | Rw 44 dB | Glass Wall | 80 / 88 mm (3-1/8 / 3-7/16 in) |
Rw ratings per ISO 717-1. NW840-W: Rw up to 55 dB; STC 55 verified per ASTM E90 (report XMIN180500970CCM). NG840 glass wall rated Rw 44 dB (report G21024AC226048).
Testing Standards
How Acoustic Ratings are Measured
Sound Source Generation
A standardized sound source generates noise at various frequencies in the source room.
Sound Level Measurement
Sound levels are measured in both the source and receiving rooms across frequencies.
Transmission Loss Calculation
The difference in sound levels determines the transmission loss at each frequency.
Rating Assignment
Results are compared to standard curves (ASTM E413 for STC, ISO 717-1 for Rw) to assign the final rating.
Need Help Choosing the Right STC Rating?
Our acoustic experts can help you select the perfect partition system for your specific requirements.