Masonry Magazine April 1972 Page. 19
TRANSMISSION LOSS, DB.
70
60+
50
40
30
SOUND TRANSMISSION
CLASS CONTOURS
A NON MASONRY WALL
AN ACOUSTICAL HOLE
FIGURE 1
STL curves for walls and ASTM E 90-66
contours for determining STC
20
4" HOLLOW CONCRETE MASONRY,
NO SURFACE TREATMENT
10-
0
125 175 250 350 500 700 1000
2000
4000
FREQUENCY, CPS
TABLE 2
Sound Transmission Class Limitations
| Location of Partition | Low Background Noise | High Background Noise |
|---|---|---|
| | Bedroom adjacent to partition | Other rooms adjacent to partition | Bedroom adjacent to partition | Other rooms adjacent to partition |
| Living Unit to Living Unit | 50 | 45 | 45 | 40. |
| Living Unit to corridor | 45 | 40 | 40 | 40 |
| Living Unit to Public Space (Average Noise) | 50 | 50 | 45 | 45 |
| Living Unit to Public Space & Service Areas (High Noise) | 55 | 55 | 50 | 50 |
| Bedrooms to other rooms within same living unit | 45 | NA | 40 | NA |
| NA-Not applicable | | | | |
| Environment | Background Noise Level (db) | Privacy Desired | Minimum STC Required |
|---|---|---|---|
| Kural | 20 | High | 60 |
| | | Medium | 50 |
| | | Low | 45 |
| Suburban | 30 | High | 55 |
| | | Medium | 45 |
| | | Low | 40 |
| Urban | 40 | High | 45 |
| | | Medium | 40 |
| | | Low | 35 |
TABLE 3
STC Require-
ments for
Various Degrees
of Privacy and
Levels of Back-
ground Noise
SOUND TRANSMISSION CLASS
(ASTM E 90-66 T)
60
50
30
40 50 60 70 80
WALL WEIGHT-POUNDS PER SQ. FT.
FIGURE 2
STC vs. Wall
Weight for
Single-Wythe
Painted or
Plastered lock
Walls
40
20