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Acoustics <br />Audiovisual <br />Telecommunications <br />Security <br />130 Sutter Street <br />F rir.,r 5 <br />San Fr0nc.,ro CA <br />94104 <br />T 415397 0442 <br />F 415 3970454 <br />v.v./veCTo ter „Im <br />536 St. John Street Residences Environmental Noise and Vibration Study <br />1 July 2016 Page 3 <br />above grade. The measured levels and a description of the monitor locations are shown in the <br />following table and Figure 1. <br />We calculated noise levels at the various building facades using our measured data. A future traffic <br />analysis was not provided for this project. However, we have added 1 dB to the data in our calculations <br />to account for future traffic increases.5 <br />Site <br />Table 2: Summary of Noise Measurement Results <br />Location <br />Measured DNL <br />(dBA6) <br />LT -1 <br />Along St. John Street, 30 feet south of the <br />St. John Street centerline, 236 feet west of <br />Peters Avenue centerline, 12 feet above <br />grade <br />70 <br />Measured <br />Lmax30 !! <br />89 <br />LT -2 <br />Along Peters Avenue Street, 40 feet east of <br />the Peters Avenue centerline, 147 feet south <br />of St. John Street centerline, 12 feet above <br />grade <br />ASSESSMENT OF GROUNDBORNE VIBRATION <br />68 <br />82 <br />We conducted attended vibration measurements on 14 June 2016 (see Figure 1 for measurement <br />locations). The two measurement locations were set back approximately 180 feet and 310 feet from <br />the centerline of the tracks. We measured a total of four trains passing the site (four ACE trains). <br />During our visit, there were no freight trains. The vibration levels of those trains are shown below in <br />Table 2 below. <br />Table 3: On -Site Measured Vibration Data (VdB re 1 p -in /sec) for ACE Trains <br />Train Event <br />Train <br />Direction <br />180 ft <br />setback <br />Vi <br />310 ft <br />setback <br />(V2) <br />ACE <br />Westbound <br />90 <br />79 <br />ACE <br />Westbound <br />89 <br />80 <br />ACE <br />Eastbound <br />89 <br />81 <br />ACE <br />Eastbound <br />88 <br />78 <br />s <br />6 <br />The California Department of Transportation assumes a traffic volume increase of three - percent per year, which <br />corresponds to a 1 dB increase in DNL over a ten -year period. <br />A- Weighted Sound Level — The A- weighted sound pressure level, expressed in decibels (dB). Sometimes the unit of sound <br />level is written as dB(A). A weighting is a standard weighting that accounts for the sensitivity of human hearing to the <br />range of audible frequencies. People perceive a 10 dB increase in sound level to be twice as loud. <br />z:l <br />ch-gles W\ Salter <br />ASSOCrA'r` !IC <br />