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WSB Engineering Carwash Noise Impact Assessment David Braslau Associates, Inc. Page 11 5.0 PREDICTED LEVELS RELATIVE TO NOISE STANDARDS Predicted L50 sound levels for all sources combined and for each source separately are presented in Table 5.1. The KenA1 receptor is the lowest balcony closest to the west entry. The KenE1 is a fifth-floor receptor closest to the west carwash entry, while the B through D receptors are between these two. It can be seen that differences in balcony elevation have only a small impact on overall sound levels. Table 5-1 Sound Level Model Predictions KenA1 KenB1 KenC1 KenD1 KenE1 Wal01 Wal2 Wal3 Wal4 Home1 Home2 Home3 Home4 Home5 Home6 All -Source dBA 65 64 64 64 64 58 58 57 56 52 57 63 63 63 61 Entry WEST 63 63 63 62 62 48 48 33 32 49 54 39 37 35 32 Exit EAST 52 52 52 53 53 57 57 56 56 48 54 63 63 63 61 Vac1 51 51 51 50 50 39 39 38 37 28 32 28 28 27 25 Vac2 50 50 50 50 49 39 39 38 37 28 32 28 28 27 25 Vac3 49 49 49 49 49 39 39 38 37 27 31 28 28 27 26 Vac4 49 49 49 48 48 39 39 38 37 27 31 28 28 27 26 Vac5 48 48 48 48 48 39 39 38 38 27 31 28 28 27 26 Vac6 48 47 47 47 47 39 39 38 38 27 31 28 28 27 26 Vac7 47 47 47 47 47 39 39 38 38 27 31 28 28 27 26 Vac8 46 46 46 46 46 39 39 38 38 27 31 28 28 28 26 Vac9 46 46 46 46 46 39 39 38 38 26 31 28 28 28 26 The overall values in red type are estimated to exceed the daytime residential L50 standard of 60 dBA. The values in bold, associated with either the entry on the west where preliminary washing takes place, or on the east where drying takes place are the primary contributors to the overall levels. The dominant source adjacent to the Kenzington Condominiums is the west entry, which is assumed to be open for this analysis. The receptor middle homes and the Walker residence are further from these sources and partially shielded by the carwash building. Figure 5.1 shows the sound level spectra of contributing sources to the closest Kenzington receptor A1. Only three distributed vacuum sources are included for this demonstration. Note that the west entry wash spectrum dominates the spectra. The higher 125 Hz level from the dryer was probably related to some mechanical fan noise and less shielded (in the model) by the building. Otherwise, the vacuum levels are generally higher than the dryer at this receptor. 77