| Severity index (S) | Noise measured |
| 5 | - |
| 4 | LEX,8h > 87 dB(A) |
| LCpeak > 140 dB(C) | |
| 3 | 85 < LEX,8h ≤ 87 dB(A) |
| 137 < LCpeak ≤ 140 dB(C) | |
| 2 | 80 < LEX,8h ≤ 85 dB(A) |
| 135 < LCpeak ≤ 137 dB(C) | |
| 1 | LEX,8h ≤ 80 dB(A) |
| LCpeak ≤ 135 dB(C) |