Appendix I Noise and Vibration Impact Assessment Methodology
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APPENDIX I NOISE AND VIBRATION IMPACT ASSESSMENT METHODOLOGY NOISE AND VIBRATION IMPACT ASSESSMENT METHODOLOGY TABLE OF CONTENTS Section Page I.1 Noise and Vibration Terminology...........................................................................................I-1 I.2 Noise Analysis Methodology ..................................................................................................I-2 I.2.1 Wayside Noise Model Methodology ................................................................................I-3 I.2.2 Horn Noise Model Methodology ......................................................................................I-5 I.3 Vibration Analysis Methodology ............................................................................................I-7 I.3.1 Construction Vibration .....................................................................................................I-7 I.3.2 Train Vibration .................................................................................................................I-7 I.4 Glossary...................................................................................................................................I-8 I.5 References ...............................................................................................................................I-8 LIST OF TABLES Table Page I-1 Benchmark ground-vibration criteria for buildings and human annoyance...................................I-2 I-2 Reference noise levels ....................................................................................................................I-4 LIST OF FIGURES Figure Page I-1 Horn noise spectrum ......................................................................................................................I-6 I-2 Wayside noise spectrum ................................................................................................................I-6 I-3 Generalized ground surface vibration curves.................................................................................I-7 I-iii NOISE AND VIBRATION IMPACT ASSESSMENT METHODOLOGY APPENDIX I NOISE AND VIBRATION IMPACT ASSESSMENT METHODOLOGY This appendix provides detailed information on the methodology DOE used to develop the assessment of potential impacts from noise and vibration described in Sections 4.2.8 and 4.3.8 of the Rail Alignment EIS (DOE/EIS-0639D). Section I.4 defines terms shown in bold italics. I.1 Noise and Vibration Terminology Noise is considered a source of pollution because it can be a human health hazard. Potential health hazards range from hearing impairment at very high noise levels to annoyance at moderate to high noise levels. Noise is defined as sound waves that are unwanted and perceived as a nuisance by humans. Sound waves are characterized by frequency and measured in hertz; sound pressure level is expressed as decibels (dB). With the exception of prohibiting nuisance noise, neither the State of Nevada nor local governments have established numerical noise standards. Many federal agencies use day-night average noise levels (DNL) as guidelines for land-use compatibility and to assess the impact of noise on people. Noise levels for perceptible frequencies are weighted (A-weighted decibels [dBA]) to simulate the frequency response of the human ear. Wayside noise refers collectively to train noise generated by steel wheels rolling on steel rail and diesel engine noise. Horn noise refers to the sound of locomotive warning horns, which are sounded at railroad crossings. Horn noise typically dominates over wayside noise at locations near grade crossings. There are three ground-vibration impacts of general concern: annoyance to humans, damage to buildings, and interference with vibration-sensitive activities. There are two measurements for evaluating ground vibration: peak particle velocity and root-mean- square velocity. Peak particle velocity is the maximum instantaneous positive or negative peak of the vibration signal, measured as a distance per time Peak particle and root-mean-square (such as millimeters or inches per second). This vibration velocity measurement has been used historically to evaluate shock-wave type vibrations from actions like blasting, pile driving, and mining activities, and their relationship to building damage. The root-mean-square velocity is an average or smoothed vibration amplitude, commonly measured over 1-second intervals. It is expressed on a log scale in decibels (VdB) referenced to 0.000001 (10-6) inch per second and is not to be confused with noise decibels (DIRS 155970-DOE 2002, p. 3-101). It is more suitable for addressing human annoyance and characterizing background vibration conditions because it better represents the response time of humans to ground vibration signals. A typical background level of ground vibration is DOE/EIS-0369 I-1 NOISE AND VIBRATION IMPACT ASSESSMENT METHODOLOGY 52 VdB, and the human threshold for the perception of ground vibration is 65 VdB (DIRS 148155 Hanson, Saurenman, and Towers 1998, p. 46.17). Vibration criteria for structural damage in fragile or extremely fragile buildings have separate structural criteria based on peak particle velocity and an approximation of VdB that have been segregated into impulse and rail impacts. Table I-1 lists these criteria. Table I-1. Benchmark ground-vibration criteria for buildings and human annoyance.a Infrequent events (fewer than 70 per day) Peak particle Frequent events velocity (more than 70 (inches per Category per day) VdBb second)c VdB Impact of concern Annoyance or interference Highly sensitive buildingd 65 NAe 65 Sensitive equipment Residentialf 72 NA 80 Human disturbance Institutionalg 75 NA 83 Human disturbance Structural damage Fragile buildings NA 0.20 Approximately Structural damage 100 (impulse) 92 (rail) Extremely fragile buildings NA 0.12 Approximately Structural damage 95 (impulse) 88 (rail) a. Source: DIRS 177297- Hanson, Towers, and Meister 2006, pp. 8-3 and 12-13. -6 b. Root-mean-square velocity expressed in decibels (VdB) referenced to 10 inch per second. c. To convert to millimeters per second, multiply by 25.4. d. Buildings with vibration-sensitive equipment (for example, at research institutions and medical facilities). e. NA = not applicable. f. Homes or buildings where people sleep. g. Schools, churches, and office buildings. I.2 Noise Analysis Methodology DOE used the following methods to determine if constructing and operating the proposed rail line would result in an increase of the DNL of 3 dBA and if the DNL would equal or exceed 65 dBA: • Noise Models – DOE used a wayside noise model, based on past Surface Transportation Board (STB) noise studies including the Conrail Acquisition Environmental Impact Statement (DIRS 174622 STB 1997, all) and the Draft Environmental Assessment for the Canadian National/Illinois Central Acquisition Environmental Assessment (DIRS 174623-Kaiser 1998, all). Section I.2.1 lists the equations for this model. The horn noise model is based on data from the Draft Environmental Impact Statement, Proposed Rule for the Use of Locomotive Horns at Highway-Rail Grade Crossings (DIRS 174551-DOT 1999, all; the 1999 Federal Railroad Administration DEIS). The overall noise model results are sensitive to horn noise, locomotive and railcar noise, train length, and train speed. DOE used wayside reference levels, the horn noise model, and equations shown in this appendix to generate noise contours. Finally, DOE used Cadna (DIRS 178129-DataKustik [n.d.], all), an environmental noise computer program, to calculate building shielding effects, where appropriate. DOE/EIS-0369 I-2 NOISE AND VIBRATION IMPACT ASSESSMENT METHODOLOGY DOE selected the individual components of the overall noise model because of the size of the noise measurement database, statistical reliability, and other factors. • Measure Ambient Noise – To establish a baseline for determining if there would be a 3 dBA or greater increase in noise, DOE measured ambient noise in the study area at seven representative locations – Caliente, Garden Valley, Goldfield, Silver Springs, Schurz, Mina, and Silver Peak. Substantial train activity already exists in Caliente; therefore, DOE used a combination of modeling and measurements to determine the difference between existing and future noise levels in that area. DOE measured ambient noise levels using Norsonics 118 octave band analyzers. For low ambient sound environments, DOE used special low-noise 1-inch-diameter precision microphones. DOE measured vibration levels with a Rion SA-77 narrow band analyzer and high sensitivity seismic accelerometers. • Estimate or Measure Existing and Future Noise Exposure – DOE estimated noise exposure in terms of the DNL using information on distances and noise propagation paths to sensitive receptors and future operation plans. • Count Noise-Sensitive Receptors – DOE estimated the number of noise-sensitive receptors within the 65 DNL noise contours for the Proposed Action and Shared-Use Option, or where the DNL would increase by at least 3 dBA. DOE used digital aerial photographs and Geographic Information System software to estimate the number of receptors, including residences, schools, and places of worship, within the 65 DNL noise contour for future train volumes. The final result of this analysis was an estimate of the total number of receptors likely to be exposed to a DNL of 65 dBA or greater and the number of receptors where the DNL would increase by at least 3 dBA under the Proposed