Definitions of Acoustical Terms

Transcription

1 Appendix E Noise

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3 Definitions of Acoustical Terms Sound Measurements Decibel (db) A Weighted Decibel (dba) Maximum Sound Level (Lmax) Minimum Sound Level (Lmin) Equivalent Sound Level (Leq) Percentile Exceeded Sound Level (Lxx) Community Noise Equivalent Level (CNEL) Peak Particle Velocity (Peak Velocity or PPV) Frequency: Hertz (Hz) Definition A unitless measure of sound on a logarithmic scale, which indicates the squared ratio of sound pressure amplitude to a reference sound pressure amplitude. The reference pressure is 20 micro pascals. An overall frequency weighted sound level in decibels that approximates the frequency response of the human ear. The maximum sound level measured during the measurement period. The minimum sound level measured during the measurement period. The equivalent steady state sound level that in a stated period of time would contain the same acoustical energy. The sound level exceeded xx % of a specific time period. L10 is the sound level exceeded 10% of the time. L90 is the sound level exceeded 90% of the time. L90 is often considered to be representative of the background noise level in a given area. To account for the fluctuation in noise levels over time, noise impacts are commonly evaluated using time averaged noise levels. The Community Noise Equivalent Level (CNEL) represents an energy average of the A weighted noise levels over a 24 hour period with 5 dba and 10 dba increases added for nighttime noise between the hours of 7:00 p.m. and 10:00 p.m. and 10:00 p.m. to 7:00 a.m., respectively. The increases were selected to account for reduced ambient noise levels during these time periods and increased human sensitivity to noise during the quieter periods of the day. A measurement of ground vibration defined as the maximum speed (measured in inches per second) at which a particle in the ground is moving relative to its inactive state. PPV is usually expressed in inches/second (in/s). The number of complete pressure fluctuations per second above and below atmospheric pressure.

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15 14:00:00 16:00:00 18:00:00 20:00:00 22:00:00 0:00:00 2:00:00 4:00:00 6:00:00 8:00:00 10:00:00 12:00:00 14:00:00 16:00:00 18:00:00 20:00:00 22:00:00 0:00:00 2:00:00 4:00:00 6:00:00 8:00:00 10:00:00 12:00:00 14:00:00 16:00:00 18:00:00 20:00:00 22:00:00 0:00:00 2:00:00 4:00:00 6:00:00 8:00:00 10:00:00 12:00:00 14:00: LT Tiara Street 5/4/2015 5/5/2015 5/6/2015 5/7/2015 Date / Time Leq (1h) dba

16 8:00:00 18:00:00 20:00:00 22:00:00 0:00:00 2:00:00 4:00:00 6:00:00 8:00:00 10:00:00 12:00:00 14:00:00 16:00:00 18:00:00 20:00:00 22:00:00 0:00:00 2:00:00 4:00:00 6:00:00 8:00:00 10:00:00 12:00:00 14:00:00 16:00:00 18:00:00 20:00:00 22:00:00 0:00:00 2:00:00 4:00:00 6:00: LT Tiara Street 5/7/2015 5/8/2015 5/9/2015 5/10/2015 Date / Time Leq (1h) dba

17 18:00:00 20:00:00 22:00:00 0:00:00 2:00:00 4:00:00 6:00:00 8:00:00 10:00:00 12:00:00 14:00:00 16:00:00 18:00:00 20:00:00 22:00:00 0:00:00 2:00:00 4:00:00 6:00:00 8:00:00 10:00:00 12:00:00 14:00:00 16:00:00 18:00:00 20:00:00 22:00:00 0:00:00 2:00:00 4:00:00 6:00:00 8:00:00 10:00:00 12:00:00 14:00: LT Tiara Street 5/4/2015 5/5/2015 5/6/2015 5/7/2015 Date / Time Leq (1h) dba

18 Table 1. Average Equipment Noise Levels at 50 feet Equipment Typical Barrier Usage Number Distance to Hard or Attenuation, Leq(h), Item No. Description 50', dba 1 Factor 1,2 of Units Receiver, ft. Soft Site? db dba 23 Grader hard Hammer, Jack hard Dozer hard Truck, Dump hard Loader (Front End Loader) hard Compactor hard Backhoe hard Crane hard Roller hard Paver hard Obtained or estimated from: FHWA Roadway Construction Noise Model (RCNM), Version 1.1, December 8, Usage Factor = percentage of time equipment is operating in noisiest mode while in use

19 Table 2. Construction Noise Analysis Equipment Typical Barrier Usage Number Distance to Hard or Attenuation, Leq(h), Item No. Description 50', dba 1 Factor 1,2 of Units Receiver, ft. Soft Site? db dba 23 Grader hard Hammer, Jack hard Dozer hard Combined Noise Level at 50 Feet Grader hard Hammer, Jack hard Dozer hard Combined Noise Level at Nearest Homes Obtained or estimated from: FHWA Roadway Construction Noise Model (RCNM), Version 1.1, December 8, Usage Factor = percentage of time equipment is operating in noisiest mode while in use

20 General notes: three vehicles; regular firetruck and large ladder firetruck exiting from existing gate to proposed site; EMT vehicle originates on Vesper and comes out onto Oxnard Emergency Vehicle Passby Measurements Passby Local Time at Start of Recording File Time at Start of Siren Local Time at File Time at End Local Time at Start of Siren of Siren End of Siren Duration Vehicle Type Vehicle Direction Notes 1) 13:24:29 03:55 13:28:24 04:19 13:28: Firetruck West Siren quality changes; as siren trails out, a truck takes over noise profile, then siren reappears after truck has passed. The end time of the siren here includes truck passing. 2) 13:24:29 06:53 13:31:22 07:10 13:31: Firetruck West Horn impulse and short siren burst directly precedes the actual siren and passby; this was not included in times listed here 3) 13:24:39 08:14 13:32:53 08:31 13:33: Firetruck West 4) 13:24:39 10:56 13:35:35 11:14 13:35: Firetruck West Sound of nearby vehicles masks the ending of the siren decay. For LxT data: homeowner slammed door during decay of siren 5) 13:24:39 12:38 13:37:17 12:53 13:37: Firetruck East In opposite lane of traffic to get around cars waiting at light 6) 13:24:39 15:34 13:40:13 15:56 13:40: Firetruck East Vehicle passing by during siren decay creates slight swell in noise level 7) 13:24:39 18:25 13:43:04 18:58 13:43: EMT West Long lead in before vehicle passes by meter and reaches max level. JH: small vehicle measured across gate. 8) 13:24:39 19:59 13:44:38 20:34 13:45: Firetruck/EMT East/West (respectively) Two vehicles passing in sequence; firetruck passes first, then EMT becomes audible around 20 min, 7.5 sec. in file; firetruck becomes inaudible around 20 min, 16.5 sec. as EMT vehicle begins to dominate noise spectrum 9) 13:24:39 21:28 13:46:07 21:54 13:46: EMT West 10) 13:24:39 22:57 13:47:36 23:25 13:48: EMT West 11) 13:24:39 24:32 13:49:11 24:48 13:49: Firetruck East Full siren decay masked by passing vehicles 12) 13:54:31 03:41 13:58:12 04:07 13:58: Large Ladder Firetruck + Firetruck West Two vehicles passing in sequence; multiple siren types/horns 13) 13:54:31 05:20 13:59:51 05:37 14:00: Large Ladder Firetruck + Firetruck West 14) 13:54:31 06:49 14:01:20 07:06 14:01: Large Ladder Firetruck + Firetruck East 15) 13:54:31 07:42 14:02:13 08:05 14:02: Large Ladder Firetruck + Firetruck East Two vehicles passing in sequence; short siren burst preceding full passby; this burst is not included in times recorded here; abrupt end to siren noise Two vehicles passing in sequence; intermittent siren sound; abrupt ending siren noise; vehicles turned out of project site and only went as far as vesper before turning and ceasing siren. For LxT data: tree rustling during siren decay Two vehicles in sequence; vehicles went past vesper; nearby truck is audible during measurement and I believe it sounds its horn, although it might have been the firetruck. For LxT data: I was talking into recording device about 20 feet away from microphone during start of siren; probably not loud enough to contaminate data but should be noted 16) 15:09:04 10:07 15:19:11 10:32 15:19: EMT East 17) 15:09:04 11:14 15:20:18 11:31 15:20: EMT West Vehicle starts eastward on Oxnard and goes straight through vesper along Oxnard 18) 15:09:04 14:38 15:23:42 14:52 15:23: EMT West Loud passing vehicle masks decay of siren 19) 15:09:04 19:12 15:28:16 19:29 15:28: EMT East 20) 15:09:04 23:50 15:32:54 24:01 15:33:05 XX EMT West Didn't turn on siren until after turn was cleared; low noise levels; decay masked by other passing vehicles 21) 15:09:04 26:48 15:35:52 27:00 15:36: EMT East Didn't turn on siren until after turn was cleared 22) 15:09:04 34:10 15:43:14 34:23 15:43: EMT East Didn't turn on siren until after turn was cleared

21 Passby Measurement Statistics Record Typ1/10 s RecDate Time LAeq Leq Lmax Lmin L10 L50 L /15/ :28: /15/ :31: /15/ :32: /15/ :35: /15/ :37: /15/ :40: /15/ :43: /15/ :44: /15/ :46: /15/ :47: /15/ :49: /15/ :58: /15/ :59: /15/ :01: /15/ :02: /15/ :19: /15/ :20: /15/ :23: /15/ :28: /15/ :35: /15/ :43: Passby 1/3 Octave Band Spectra Record Typ1/10 s RecDate Time Event Total Energy (1/10 s SEL) /15/ :28: /15/ :31: /15/ :32: /15/ :35: /15/ :37: /15/ :40: /15/ :43: /15/ :44: /15/ :46: /15/ :47: /15/ :49: /15/ :58: /15/ :59: /15/ :01: /15/ :02: /15/ :19: /15/ :20: /15/ :23: /15/ :28: /15/ :35: /15/ :43:

22 Emergency Vehicle Trips Vehicle type Responses Proportion of total emergency calls EMT Vehicle exit Northbound % EMT Vehicle exit South to Westbound % EMT Vehicle exit South to Eastbound % Fire Truck Westbound % Fire Truck Eastbound % Ladder Truck Westbound % Ladder Truck Eastbound % Total % Exit Direction North on Vesper Avenue 42.50% West on Oxnard Street 28.75% East on Oxnard Street 28.75% Total %

23 Tiara Street Passby Time Histories Tiara Tiara Passby # Time LAeq Time 1 second Leq 13:31: :31:16 PM 50 13:31: :31:17 PM :31: :31:18 PM :31: :31:19 PM :31: :31:20 PM :31: :31:21 PM :31: :31:22 PM :31: :31:23 PM :31: :31:24 PM :31: :31:25 PM :31: :31:26 PM :31: :31:27 PM :31: :31:28 PM :31: :31:29 PM :31: :31:30 PM :31: :31:31 PM :31: :31:32 PM :31: :31:33 PM :31: :31:34 PM :31: :31:35 PM :31: :31:36 PM :31: :31:37 PM :31: :31:38 PM :31: :31:39 PM :31: :31:40 PM :31: :31:41 PM :31: :31:42 PM :31: :31:43 PM :40: :40:08 PM :40: :40:09 PM :40: :40:10 PM :40: :40:11 PM :40: :40:12 PM :40: :40:13 PM 52 13:40: :40:14 PM :40: :40:15 PM :40: :40:16 PM :40: :40:17 PM :40: :40:18 PM :40: :40:19 PM :40: :40:20 PM :40: :40:21 PM :40: :40:22 PM :40: :40:23 PM :40: :40:24 PM :40: :40:25 PM :40: :40:26 PM :40: :40:27 PM :40: :40:28 PM :40: :40:29 PM :40: :40:30 PM :40: :40:31 PM :40: :40:32 PM :40: :40:33 PM :40: :40:34 PM :40: :40:35 PM :40: :40:36 PM 50.7

24 13:40: :40:37 PM 51 13:40: :40:38 PM :40: :40:39 PM :40: :40:40 PM :58: :58:08 PM :58: :58:09 PM :58: :58:10 PM :58: :58:11 PM :58: :58:12 PM :58: :58:13 PM :58: :58:14 PM :58: :58:15 PM :58: :58:16 PM :58: :58:17 PM :58: :58:18 PM :58: :58:19 PM :58: :58:20 PM :58: :58:21 PM :58: :58:22 PM :58: :58:23 PM :58: :58:24 PM :58: :58:25 PM :58: :58:26 PM :58: :58:27 PM :58: :58:28 PM :58: :58:29 PM :58: :58:30 PM :58: :58:31 PM :58: :58:32 PM :58: :58:33 PM :58: :58:34 PM :58: :58:35 PM :58: :58:36 PM :58: :58:37 PM :58: :58:38 PM :58: :58:39 PM :58: :58:40 PM :58: :58:41 PM :58: :58:42 PM 54 14:02: :02:09 PM :02: :02:10 PM :02: :02:11 PM :02: :02:12 PM :02: :02:13 PM :02: :02:14 PM :02: :02:15 PM :02: :02:16 PM :02: :02:17 PM :02: :02:18 PM :02: :02:19 PM :02: :02:20 PM :02: :02:21 PM :02: :02:22 PM :02: :02:23 PM :02: :02:24 PM :02: :02:25 PM :02: :02:26 PM :02: :02:27 PM :02: :02:28 PM :02: :02:29 PM :02: :02:30 PM 62.8

25 15 14:02: :02:31 PM :02: :02:32 PM :02: :02:33 PM :02: :02:34 PM :02: :02:35 PM :02: :02:36 PM :02: :02:37 PM :02: :02:38 PM :02: :02:39 PM 53 14:02: :02:40 PM :23: :23:37 PM :23: :23:38 PM :23: :23:39 PM :23: :23:40 PM :23: :23:41 PM :23: :23:42 PM :23: :23:43 PM :23: :23:44 PM :23: :23:45 PM :23: :23:46 PM :23: :23:47 PM :23: :23:48 PM :23: :23:49 PM :23: :23:50 PM :23: :23:51 PM :23: :23:52 PM :23: :23:53 PM :23: :23:54 PM :23: :23:55 PM :23: :23:56 PM :23: :23:57 PM :23: :23:58 PM :23: :23:59 PM :24: :24:00 PM :24: :24:01 PM :24: :24:02 PM :24: :24:03 PM :24: :24:04 PM :35: :35:47 PM :35: :35:48 PM :35: :35:49 PM 59 15:35: :35:50 PM :35: :35:51 PM :35: :35:52 PM :35: :35:53 PM :35: :35:54 PM :35: :35:55 PM :35: :35:56 PM :35: :35:57 PM :35: :35:58 PM :35: :35:59 PM :36: :36:00 PM :36: :36:01 PM :36: :36:02 PM :36: :36:03 PM :36: :36:04 PM :36: :36:05 PM :36: :36:06 PM 55 15:36: :36:07 PM :36: :36:08 PM 54.6

26 Measured Levels for emergency vehicle passbys Tiara Measured Modeled Delta Passby Vehcle Type Leq, event SEL Leq Leq 2 Fire Truck WB Fire Truck EB Ladder WB Ladder EB EMT WB EMT EB * * Tiara Measured Modeled Delta Passby Vehcle Type Leq, event SEL Leq 2 Fire Truck WB Fire Truck EB Ladder WB Ladder EB EMT WB EMT EB * * * This was an EMT vehicle exiting eastbound to Oxnard Street, deemed too far from backyard locations to calibrate.

27 K:\Irvine\GIS\Projects\LABOE\00135_15\Fig0E_1_Noise_Barriers.mxd Date: 1/20/ ± Feet Source: Bing Imagery (2014) Legend Fire Station 39 Project Site Boundary Noise Barriers Figure E-1 Location of Noise Barriers Recommended in MM NOI-2 Van Nuys Fire Station

28 Predicted Noise Levels from Emergency Response Vehicle Events from the Proposed Fire Station 39 Site, With Mitigation Receptor ID Address Project CNEL After Mitigation A Tiara Street, Van Nuys 62.1 B Tiara Street, Van Nuys 59.7 C Tiara Street, Van Nuys 61.3 D Tiara Street, Van Nuys 61.7 E Tiara Street, Van Nuys 60.9 F Tiara Street, Van Nuys 60.5 G Tiara Street, Van Nuys 60.4 H Tiara Street, Van Nuys 62.9 I 5945 Tobias Avenue, Van Nuys 61.7 J 5941 Tobias Avenue, Van Nuys 57.5 K 5938 Tobias Avenue, Van Nuys 57.2 L 5939 Vesper Avenue, Van Nuys 59.4 M 5940 Vesper Avenue, Van Nuys 66.0