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Standard Index for noise measurements incorporating PSI values as well as equivalent noise levels.
| PSI values | Index category | Equivalent noise levels (dBA) | Noise description |
|---|---|---|---|
| < 100 | Very good quality | 20 | Very quiet |
| 100 | Good quality | 50 | Quiet |
| 200 | Satisfactory | 70 | Noisy |
| 300 | Unhealthy | 90 | Very noisy |
| 400 | Hazardous | 100 | Unbearable |
| 500 | Seriously hazardous | 130 | Seriously hazardous |
