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HomeMy WebLinkAboutSDP 2023-0025; GRAND HOPE MEDICAL OFFICE; NOISE STUDY; 2024-01-01 GRAND AVENUE/HOPE AVENUE MEDICAL OFFICE BUILDING PROJECT NOISE STUDY Prepared for: William Cho 3144 El Camino Real #104 Carlsbad, CA 92008 Prepared by: January 2024 €)6)© 81 IRDSEYE PILANINIIIING GR,QUP Grand and Hope Medical Office Building Noise Study City of Carlsbad Table of Contents Page Project Description ..................................................................................................................................... 2 Setting .......................................................................................................................................................... 2 Overview of Sound Measurement ................................................................................................. 2 Sensitive Receptors .......................................................................................................................... 5 Project Site Setting ............................................................................................................................ 7 Regulatory Setting ............................................................................................................................ 8 Impact Analysis ........................................................................................................................................ 10 Methodology and Significance Thresholds ................................................................................ 10 Temporary Construction Noise .................................................................................................... 11 Construction Noise Reduction Measures ................................................................................... 12 Residual Impacts ............................................................................................................................ 13 Temporary Construction-Related Vibration .............................................................................. 13 Long-Term Operational Noise Exposure .................................................................................... 14 References ................................................................................................................................................. 20 List of Figures Figure 1 - Project Location ........................................................................................................................ 3 Figure 2 – Proposed Site Plan ................................................................................................................... 4 Figure 3 – Noise Monitoring Locations ................................................................................................... 9 Figure 4 – Sensitive Properties ............................................................................................................... 16 List of Tables Table 1 – Sound Levels of Typical Noise Sources and Noise Environments ..................................... 6 Table 2 – Noise Monitoring Results......................................................................................................... 8 Table 3 – Typical Construction Equipment Noise Levels .................................................................. 11 Table 4 – Typical Maximum Construction Noise Levels at Various Distances from Project Construction ................................................................................................................ 12 Table 5 – Vibration Source Levels for Construction Equipment ....................................................... 14 Table 6 – Modeled Noise Levels ............................................................................................................ 15 Appendices Appendix A Noise Monitoring Data @&© BIRDSEYE PLANNING GROUP Grand and Hope Medical Office Building Project Noise Study 2 City of Carlsbad GRAND AND HOPE MEDICAL OFFICE BUILDING PROJECT CARLSBAD, CALIFORNIA NOISE STUDY This report is an analysis of the potential noise impacts associated with the construction and operation of a new medical office building at the northwest corner of Grand Avenue and Hope Avenue in the City of Carlsbad. The report has been prepared by Birdseye Planning Group, LLC, under contract to the applicant to support the environmental review process and address comments provided by the City of Carlsbad after review of the project entitlement submittal. This study analyzes the potential for temporary impacts associated with construction activity and long-term impacts associated with operation of the proposed project. PROJECT DESCRIPTION The project site located at 2879-85 Hope Avenue at the northwest corner of Grand Avenue and Jefferson Street. (APN 202-203-13). The project would replace an existing one-story medical office building with a new two-story medical office building. The proposed building would be a total of 7,177 square feet, excluding the garage space. The ground floor would be 2,298 square feet with a 426 square foot lobby. The second floor would be 4,453 square feet. A total of 11 parking spaces would be provided on the ground level. One space would accessible and the remaining 10 spaces would be provided using vehicle lifts each accommodating two vehicles. Construction would require the demolition and removal of the existing building which appears to be a converted single-family residence. Construction is anticipated to begin in mid-2024 and be completed in early 2025. Figure 1 provides a vicinity map; Figure 2 shows a project site plan. SETTING Overview of Sound Measurement Noise level (or volume) is generally measured in decibels (dB) using the A-weighted sound pressure level (dBA). The A-weighting scale is an adjustment to the actual sound pressure levels to be consistent with that of human hearing response, which is most sensitive to frequencies around 4,000 Hertz (about the highest note on a piano) and less sensitive to low frequencies (below 100 Hertz). Sound pressure level is measured on a logarithmic scale with the 0 dB level based on the lowest detectable sound pressure level that people can perceive (an audible sound that is not zero sound pressure level). Based on the logarithmic scale, a doubling of sound energy is equivalent @O© BIRDSEYE PLANNING GROUP Figure 1—Vicinity Map - Project Site Figure 2—Site Plan ' M.O 1£1SNl.EFIM,.lECOOW. I OE -----------~~'~:::S.=":_~~~~ .. =~~°'81~i!~ , , I , IEJ.wAAEKT.,_GNWi;_or;,, •' I' ,, ,, /1 I , , , , , I I I ] Ll SITE PLAN SOP 2023-0025 I I • I " / ' I --------------- w u u.i ~ 0 ~ (') ,---u: u. 0 ...J <( u i5 w ui IE)IU.fl.f-..Tll£li1DEHTW. ~ > w < ll. w 0 Q. < 0 0 ::c J: c" It) C (IC) < z (IC) ID N Cl) <( .J c::: a, 0: ... < (!) (IC) N 0 - LI, ...... SITE PLAN A1.1 Grand and Hope Medical Office Building Project Noise Study 5 City of Carlsbad to an increase of 3 dBA, and a sound that is 10 dBA less than the ambient sound level has no effect on ambient noise. Because of the nature of the human ear, a sound must be about 10 dBA greater than the reference sound to be judged as twice as loud. In general, a 3 dBA change in community noise levels is noticeable, while 1-2 dB changes generally are not perceived. Quiet suburban areas typically have noise levels in the range of 40-50 dBA, while arterial streets are in the 50-60+ dBA range. Normal conversational levels are in the 60-65 dBA range, and ambient noise levels greater than 65 dBA can interrupt conversations. Noise levels typically attenuate (or drop off) at a rate of 6 dBA per doubling of distance from point sources (i.e., industrial machinery). Noise from lightly traveled roads typically attenuates at a rate of about 4.5 dBA per doubling of distance. Noise from heavily traveled roads typically attenuates at about 3 dBA per doubling of distance. Noise levels may also be reduced by intervening structures; generally, a single row of buildings between the receptor and the noise source reduces the noise level by about 5 dBA, while a solid wall or berm reduces noise levels by 5 to 10 dBA. The manner in which older homes in California were constructed (approximately 30 years old or older) generally provides a reduction of exterior-to-interior noise levels of about 20 to 25 dBA with closed windows. The exterior-to-interior reduction of newer residential units and office buildings is generally 30 dBA or more. In addition to the actual instantaneous measurement of sound levels, the duration of sound is important since sounds that occur over a long period of time are more likely to be an annoyance or cause direct physical damage or environmental stress. One of the most frequently used noise metrics that considers both duration and sound power level is the equivalent noise level (Leq). The Leq is defined as the single steady A-weighted level that is equivalent to the same amount of energy as that contained in the actual fluctuating levels over a period of time (essentially, the average noise level). Typically, Leq is summed over a one-hour period. Lmax is the highest RMS (root mean squared) sound pressure level within the measuring period, and Lmin is the lowest RMS sound pressure level within the measuring period. The time period in which noise occurs is also important since noise that occurs at night tends to be more disturbing than that which occurs during the day. Community noise is usually measured using Day-Night Average Level (Ldn), which is the 24-hour average noise level with a 10-dBA penalty for noise occurring during nighttime (10 p.m. to 7 a.m.) hours, or Community Noise Equivalent Level (CNEL), which is the 24-hour average noise level with a 5 dBA penalty for noise occurring from 7 p.m. to 10 p.m. and a 10 dBA penalty for noise occurring from 10 p.m. to 7 a.m. Noise levels described by Ldn and CNEL usually do not differ by more than 1 dB. Table 1 shows sounds levels of typical noise sources measured using Leq. Sensitive Receptors Noise exposure goals for various types of land uses reflect the varying noise sensitivities associated with each of these uses. The City of Carlsbad General Plan Noise Element Update (approved September 2015) includes a variety of land use and development types that are noise sensitive including residences, schools, churches, hospitals and convalescent care facilities. @O© BIRDSEYE PLANNING GROUP Grand and Hope Medical Office Building Project Noise Study 6 City of Carlsbad Sensitive receptors are located adjacent to and surrounding the project site. The closest is a four-story multifamily building located adjacent to and west of the site at 800 Grand Avenue. Commercial and multifamily residences are the dominant land use in the area. Table 1. Sound Levels of Typical Noise Sources and Noise Environments Noise Source (at Given Distance) Noise Environment A-Weighted Sound Level (Decibels) Human Judgment of Noise Loudness (Relative to Reference Loudness of 70 Decibels*) Military Jet Takeoff with Afterburner (50 ft) Carrier Flight Deck 140 128 times as loud Civil Defense Siren (100 ft) 130 64 times as loud Commercial Jet Take-off (200 ft) 120 32 times as loud Threshold of Pain Pile Driver (50 ft) Rock Music Concert Inside Subway Station (New York) 110 16 times as loud Ambulance Siren (100 ft) Newspaper Press (5 ft) Gas Lawn Mower (3 ft) 100 8 times as loud Very Loud Food Blender (3 ft) Propeller Plane Flyover (1,000 ft) Diesel Truck (150 ft) Boiler Room Printing Press Plant 90 4 times as loud Garbage Disposal (3 ft) Noisy Urban Daytime 80 2 times as loud Passenger Car, 65 mph (25 ft) Living Room Stereo (15 ft) Vacuum Cleaner (10 ft) Commercial Areas 70 Reference Loudness Moderately Loud Normal Speech (5 ft) Air Conditioning Unit (100 ft) Data Processing Center Department Store 60 1/2 as loud Light Traffic (100 ft) Large Business Office Quiet Urban Daytime 50 1/4 as loud Bird Calls (distant) Quiet Urban Nighttime 40 1/8 as loud Quiet Soft Whisper (5 ft) Library and Bedroom at Night Quiet Rural Nighttime 30 1/16 as loud Broadcast and Recording Studio 20 1/32 as loud Just Audible @O© BIRDSEYE PLANNING GROUP Grand and Hope Medical Office Building Project Noise Study 7 City of Carlsbad 0 1/64 as loud Threshold of Hearing Source: Compiled by dBF Associates, Inc., 2016 Project Site Setting The most common and primary sources of noise in the project site vicinity are motor vehicles (e.g., automobiles, buses, trucks, and motorcycles) along Grand Avenue and Hope Avenue. Motor vehicle can be a concern when it is characterized by a high number of individual events that can create a sustained noise level in proximity to noise sensitive uses. Interstate 5 is located approximately 900 feet to the east. It is audible as background noise and contributes to overall noise levels at the project site. The Atichson, Topeka and Santa Fe Railroad (AT&SF) rail corridor is located approximately 2,000 feet west of the site. This segment of the Los Angeles – San Diego – San Luis Obispo (LOSSAN) corridor is the second busiest passenger and freight rail corridor in the United States. According to the rail timetables, up to 50 trains (40 passenger and 10 freight trains) use the corridor segment daily between Oceanside and the Santa Fe Depot in downtown San Diego. Existing wheel-rail noise and engine noise is not audible at the project site. The warning horns/bells that are used when trains are approaching or departing the Carlsbad Village Drive station are audible; thus, train noise does contribute to the ambient noise environment in the study area. McClellan-Palomar Airport is located approximately 4.0 miles southeast of the site. The site is outside the airport influence area; however, aircraft operations (airplanes and helicopters) are audible and contribute to existing noise levels in the project area. No other noise sources are near the project site. The City of Carlsbad General Plan Update Noise Element (2015) provides noise contours associated with transportation corridors (i.e., roadways, railroad and airport). This provides a graphic illustration of sound levels near road corridors, but typically does not include effects of landforms and adjacent structures. Generally, barriers between a source and receiver absorb or reflect noise resulting in a quieter environment. Where barriers or landforms do not interrupt the noise transmission path from source to receiver, the contours prove to be reasonable estimates of typical noise levels from roadway traffic. In areas where barriers or landforms interrupt the sound transmission, the noise contours overestimate the extent to which a source intrudes into neighboring areas. The noise contour distances describe worst-case conditions because they do not account for any obstructions to the noise path, such as walls, berms, or buildings. As noted, railroad noise is audible when train pass-by events occur. The contours provided in the General Plan Update Noise Element provide a reasonable prediction of rail noise levels at the site. Under existing conditions as shown in Noise Element Figure 5-2, the project site is outside the 60-65 dBA CNEL contour intervals for both the railroad track and I-5. As shown in Noise Element Figure 5-3, the project site would be within the 60-65 dBA future contour at build out which is anticipated to occur in 2040. The dominant noise source at the project site is traffic on surface streets and Interstate 5. @O© BIRDSEYE PLANNING GROUP Grand and Hope Medical Office Building Project Noise Study 8 City of Carlsbad To gather data on the general noise environment at the project site, one weekday 15-minute noise measurement were acquired in proximity to the project site on Thursday, May 25, 2023 and Tuesday June 12, 2023, using an ANSI Type II integrating sound level meter. The predominant noise source in the area during monitoring was traffic on Grand Avenue and Hope Avenue. Aircraft overflights and train pass by events contributed to ambient conditions. During monitoring, a total of 14 cars/light trucks passed the monitoring site on Hope Avenue. A total of 31 cars/light trucks and one medium truck (i.e., two axles, four-wheels) passed the site on Grand Avenue. Table 2 identifies the noise measurement location and measured noise levels. The monitoring location is shown in Figure 3. Monitoring data is provided as Appendix A. Table 2 Noise Monitoring Results Measurement Location Primary Noise Source Sample Time Leq (dBA) Project site located on Hope Avenue Traffic Weekday afternoon 54.7 Project site located on Grand Avenue Traffic Weekday morning 52.1 Source: Field visit using ANSI Type II Integrating sound level meter. Regulatory Setting In 1976, the California Department of Health, State Office of Noise Control published a recommended noise/land use compatibility matrix which many jurisdictions have adopted as a standard in their general plan noise elements. This matrix indicates that residential land uses and other noise sensitive receptors preferentially should be located in areas where outdoor ambient noise levels do not exceed 65 to 70 dBA (CNEL or Ldn). Municipal Code and Noise Guideline Manual The City of Carlsbad has established noise guidelines in Table 2 of General Plan Noise Element (City of Carlsbad, 2015) that are applicable for transportation noise sources. The noise guidelines identify compatible exterior noise levels for various land use types. Residential land uses are considered normally acceptable up to 60 dB CNEL. Commercial land uses are considered normally acceptable up to 65 dB CNEL and conditionally acceptable up to 75 dB. Interior spaces within commercial buildings are limited to 50 dBA CNEL. The City of Carlsbad Municipal Code regulates construction noise by limiting the hours of operation (City of Carlsbad 2003). Construction activities are allowed to occur Monday through Friday between the hours of 7 a.m. to sunset; and on Saturdays from 8 a.m. to sunset, excluding legal holidays. The City does not have quantitative noise level limits (i.e., based on sound levels) for general nuisance noise such as that associated with stationary equipment located on private property. @O© BIRDSEYE PLANNING GROUP Figure 3—Monitoring LocaƟons - Project Site M1 M2 Grand and Hope Medical Office Building Project Noise Study 10 City of Carlsbad For the purpose of this study, the residential standard of 60 dB CNEL is used to evaluate potential exterior noise impacts associated with the proposed project traffic at neighboring receivers. An interior noise standard of 45 dBA CNEL is used herein as referenced in the City of Carlsbad Noise Guidelines Manual (1995). Vibration Standards Vibration is a unique form of noise as the energy is transmitted through buildings, structures and the ground whereas audible noise energy is transmitted through the air. Thus, vibration is generally felt rather than heard. The ground motion caused by vibration is measured as peak particle velocity (PPV) in inches per second and is referenced as vibration decibels (VdB) for the purpose of evaluating the potential for adverse construction-related impacts. The vibration velocity level threshold of perception for humans is a PPV of approximately 0.01 inches/second which equates to 65 VdB. A vibration velocity of 75 VdB is the approximate dividing line between barely perceptible and distinctly perceptible levels. With respect to potential ground-borne vibration impacts on structures, the FTA states that ground-borne vibration levels in excess of PPV 0.2 inches/second (100 VdB) could damage fragile buildings and levels in excess of PPV 0.12 inches/second (95 VdB) could damage extremely fragile historic buildings. No historic buildings occur on the site or are known to occur near the site. Adjacent buildings are all relatively modern structure constructed consistent with applicable California Building Code and seismic standards. However, to conservatively estimate potential vibration impacts on neighboring residences, a PPV of 0.2 inches per second (100 VdB) is used herein. IMPACT ANALYSIS Methodology and Significance Thresholds Construction noise estimates are based upon noise levels reported by the Federal Transit Administration, Office of Planning and Environment, and the distance to nearby sensitive receptors. Reference noise levels from that document were used to estimate noise levels at nearby sensitive receptors based on a standard noise attenuation rate of 6 dB per doubling of distance (line-of-sight method of sound attenuation). The site is currently developed with a single-family residence used as a dental office. Noise levels associated with existing and future traffic were based on the difference in trip volumes between existing volumes counted during monitoring and the proposed use less traffic generated by the existing use. A doubling of traffic volumes would be required to cause a noticeable increase (3 dBA) in traffic noise. Thus, the two numbers were calculated to determine whether the project would generate enough traffic to increase noise levels by 3 dBA or more. The proposed use would be commercial and have no effect on ambient conditions associated with operation of the AT&SF rail line which is located approximately 2,000 feet west @O© BIRDSEYE PLANNING GROUP Grand and Hope Medical Office Building Project Noise Study 11 City of Carlsbad of the site. However, rail noise levels at the site were estimated based on methodologies approved by the Federal Rail Administration. Specific assumptions used in the analysis are described below. As noted, a noise increase greater than 3 dBA is readily perceptible to the average human ear; and thus, is the level considered a substantial noise increase related to traffic operations. However, within the City of Carlsbad, noise impacts are also considered significant if noise levels would exceed 60 dBA CNEL. For the purpose of this evaluation, the peak hour Leq is used for traffic noise as it provides a more conservative estimate of potential noise levels. The CNEL is used within the rail noise discussion. Existing noise levels at the monitoring sites are currently less than 60 dBA as shown in Table 2; thus, the determination of impact is based on whether existing exterior noise levels would exceed 60 dBA with project operation. Temporary Construction Noise The main sources of noise during construction activities would include heavy machinery used during demolition, grading, and clearing the site, as well as equipment used during building construction and paving. Table 3 shows typical noise levels associated with heavy construction equipment. As shown, average noise levels associated with the use of heavy equipment at construction sites can range from 81 to 91 dBA at 25 feet from the source, depending upon the types of equipment in operation at any given time and phase of construction. Table 3 Typical Maximum Construction Equipment Noise Levels Equipment Onsite Typical Maximum Level (dBA) 25 Feet from the Source Typical Maximum Level (dBA) 50 Feet from the Source Typical Maximum Level (dBA) 100 Feet from the Source Air Compressor 86 80 74 Backhoe 86 80 74 Bobcat Tractor 86 80 74 Concrete Mixer 91 85 79 Loader 86 80 74 Bulldozer 91 85 79 Jack Hammer 94 88 82 Pavement Roller 91 85 79 Street Sweeper 88 82 76 Man Lift 81 75 69 Dump Truck 90 84 78 Mobile Crane 89 83 77 Excavator/Scraper 91 85 79 @O© BIRDSEYE PLANNING GROUP Grand and Hope Medical Office Building Project Noise Study 12 City of Carlsbad Table 3 Typical Maximum Construction Equipment Noise Levels Equipment Onsite Typical Maximum Level (dBA) 25 Feet from the Source Typical Maximum Level (dBA) 50 Feet from the Source Typical Maximum Level (dBA) 100 Feet from the Source Source: FTA Noise and Vibration Impact Assessment Manual (September 2018), Table 7-1. Noise levels are based on actual maximum measured noise levels at 50 feet (Lmax). Noise levels are based on a noise attenuation rate of 6 dBA per doubling of distance. As noted, there are residential properties adjacent to the site and construction noise will be audible at these properties. Table 4 shows typical maximum construction noise levels at various distances from construction activity, based on a standard noise attenuation rate of 6 dBA per doubling of distance. The noise level used to estimate the maximum noise level that could occur is based on use of a bobcat tractor as it is likely to be the noisiest type of equipment used over a sustained period of time during demolition and site preparation activities. Actual noise levels will fluctuate throughout the day and may periodically exceed 84 dBA at the property line depending on the type and location of equipment used and whether multiple pieces of equipment are operating simultaneously in the same area. Table 4 Typical Maximum Construction Noise Levels at Various Distances from Project Construction Distance from Construction Maximum Noise Level at Receptor (dBA) 25 feet 84 50 feet 78 100 feet 72 250 feet 66 500 feet 60 1,000 feet 54 Construction noise levels at neighboring residences could be as high as 84 dBA. However, temporary construction noise is not restricted if it occurs between the hours specified in the noise ordinance referenced herein. While not required, temporary construction noise can be reduced by implementing one or more of the following measures. Construction Noise Reduction Measures Temporary construction noise impacts could be reduced through implementation of measures N-1 through N-4. These are not mitigation measures but can be implemented at the applicant’s discretion to reduce construction-related noise. @O© BIRDSEYE PLANNING GROUP Grand and Hope Medical Office Building Project Noise Study 13 City of Carlsbad N-1 Construction Equipment. Electrical power scan be used to run air compressors and similar power tools. Internal combustion engines should be equipped with a muffler of a type recommended by the manufacturer and in good repair. All diesel equipment should be operated with closed engine doors and should be equipped with factory-recommended mufflers. Construction equipment that continues to generate substantial noise at the project boundaries should be shielded with temporary noise barriers, such as barriers that meet a sound transmission class (STC) rating of 25, sound absorptive panels, or sound blankets on individual pieces of construction equipment. Stationary noise-generating equipment, such as generators and compressors, should be located as far as practically possible from the nearest residential property lines. N-2 Limit Operations Adjacent to Receivers. Limit the number of large pieces of equipment (i.e., backhoes or concrete mixers) operating adjacent to receivers to one at any given time. N-3 Neighbor Notification. Provide notification to residential occupants nearest to the project site at least 24 hours prior to initiation of construction activities that could result in substantial noise levels at outdoor or indoor living areas. This notification should include the anticipated hours and duration of construction and a description of noise reduction measures being implemented at the project site. The notification should include a telephone number for local residents to call to submit complaints associated with construction noise and be easily viewed from adjacent public areas. Residual Impacts Project construction would represent a temporary source of noise at the project site. Measures N-1 through N-3 could reduce construction noise levels at neighboring properties. No residual impacts associated with construction noise are anticipated. Temporary Construction-Related Vibration Activities associated with commercial projects do not generate vibration. Thus, this discussion will focus on temporary vibration caused by construction. As referenced, the closest residences to the site are located adjacent to north and west. More residences are located to the east across Hope Avenue and to the south across Grand Avenue. Based on the information presented in Table 5, vibration levels from operation of a large bulldozer would be approximately 87 VdB @O© BIRDSEYE PLANNING GROUP Grand and Hope Medical Office Building Project Noise Study 14 City of Carlsbad (0.089 inches/second) or less at 25 feet (Caltrans 2013). Grading within 25 feet of the nearest residential structures would be required. As discussed, a PPV of 0.2 inches/second (100 VdB) is the vibration energy required to damage fragile historic buildings. While vibration from grading may be perceived at neighboring residences, the vibration energy would be well below that required to cause structural damage. Vibration levels at residential buildings adjacent to the project site may exceed the groundborne velocity threshold level of 72 VdB for residences and/or buildings where people sleep as discussed above. Maximum vibration levels would range from 58 to 87 VdB depending on the type of equipment used. However, as long as construction occurs within the prescribed hours, any temporary impact would be considered adverse, but less than significant. Table 5 Vibration Source Levels for Construction Equipment Equipment Approximate VdB 25 Feet 50 Feet 60 Feet 75 Feet 100 Feet Large Bulldozer 87 81 79 77 75 Loaded Trucks 86 80 78 76 74 Jackhammer 79 73 71 69 67 Small Bulldozer 58 52 50 48 46 Source: Federal Railroad Administration, 1998 Long-Term Operational Noise Exposure Exterior Traffic Noise. Traffic is the primary noise source that would be generated by the proposed project. Thus, whether a traffic-related noise impact would occur is based on whether the project would double peak hour traffic volumes relative to existing conditions or cause noise levels to exceed 60 dBA. The peak hour is defined as the one-hour period between 7:00 am and 9:00 am and 4:00 pm and 6:00 pm when the highest volumes occur. As referenced, the existing structure is a medical office building which generates approximately 36 trips per 1,000 square feet (ITE Trip Generation Manual, 11th Edition). The structure is approximately 1,740 square feet; and thus, could generate up to 63 weekday trips. The proposed project would provide approximately 6,751 square feet (excluding the lobby and parking areas). Using the same trip generation rate, the project could generate up to 243 daily trips or 207 new daily trips. Of the total, 19 would occur during the morning peak hour and 21 would occur during the evening peak hour. Noise levels generated by traffic on Grand Avenue and Hope Avenue was modeled using the Federal Highway Administration Traffic Noise Model (TNM) version 2.5 software (see Appendix A). The model calculates traffic noise at receiver locations based on traffic volumes, @O© BIRDSEYE PLANNING GROUP Grand and Hope Medical Office Building Project Noise Study 15 City of Carlsbad travel speed, mix of vehicle types operating on the roadways (i.e., cars/trucks, medium trucks and heavy trucks) and related factors. Traffic volumes and vehicle mix used to calibrate TNM were based on vehicle counts obtained during the monitoring period. The 15-minute counts were multiplied by four to obtain hourly traffic counts. The model was calibrated to calculate noise levels that are +/- 2 dBA those measured on-site and reported in Table 2. Noise levels were calculated at the following receivers and are intended to represent conditions at multiple receivers within proximity to these locations: 1. Pacific Pines Apartments located adjacent to and north of the project site; and 2. Multi-family residences at 923 Grand Avenue across the street and south of the project site; 3. Multi-family residences located at 2886 Hope Avenue (northeast corner of Grand Avenue and Hope Avenue; and 4. Multi-family residences located at 800 Grand Avenue adjacent to and west of the project site. The receiver locations are shown in Figure 4. As shown in Table 6, the daytime hourly average (Leq) is less than the 60-dBA standard at the receivers modeled under baseline conditions. The addition of 21 peak hour trips to baseline traffic volumes would have no noticeable effect (i.e., +/- 3 dBA) on noise levels at the modeled receivers modeled nor would the traffic cause baseline conditions to exceed 60 dBA. Table 6 Modeled Noise Levels Receptor Existing Leq Exceed Standard? With Project Leq dBA Change Significant Impact Site 1 52.6 No 53.7 +1.1 No Site 2 52.6 No 53.7 +1.1 No Site 3 53.1 No 53.7 +0.6 No Site 4 54.6 No 55.3 +0.7 No Thus, long term traffic operation associated with the project would have no adverse effect on noise levels at sensitive properties within proximity to the site. Project impacts with respect to exterior traffic noise would be less than significant. Interior Traffic Noise. Current development is designed to meet or exceed California Energy Code Title 24 standards which specify construction methods and materials that result in energy efficient structures and up to a 30 dBA reduction in exterior noise levels (assuming windows are closed). Older residences typically provide a 20-25 dBA reduction in exterior noise levels. When windows are open the insertion loss drops to about 10 dBA. Assuming windows are closed, interior noise levels within the adjacent residences would be reduced from 53.7 (baseline) to between 23.7 dBA and 25.3 dBA which would be below the 45-dBA interior standard for residences. With respect to the proposed project, the interior noise levels for commercial buildings are 50 dBA as stated above. Anticipated exterior noise levels at the project site would @O© BIRDSEYE PLANNING GROUP Figure 4—Receiver Locations - Project Site R3 R2 R1 R4 Grand and Hope Medical Office Building Project Noise Study 17 City of Carlsbad be between 53.7 and 55.3 dBA. Like adjacent residential buildings, interior noise levels would be 23.7 dBA and 25.3 dBA which would be below the 45-dBA interior standard for commercial buildings. As stated, the project is anticipated to be within the 65 dBA future year (2040) noise contour. Assuming a baseline noise level of 65 dBA, a 30 dBA reduction in noise levels associated with current construction methods and materials, would result in an interior noise level of approximately 35 dBA within the proposed building. This would be within the 50 dBA standard for commercial uses. Exterior Railroad Noise. The AT&SF corridor is located approximately 2,000 feet to the west of the site and is used by Amtrak and the North County Transit District Coaster to provide passenger rail service. It is also used by freight trains during the late evening and nighttime hours. Based on the timetables, approximately 50 trains operate daily within this segment. Train volumes vary throughout the day but are generally higher during the morning and evening commute hours and reflect the dominant use of this corridor by commuter rail and passenger trains. Train noise is generated by a combination of factors including the number of locomotives, rail cars, speed, volume distribution over the day and nighttime hours and whether train horns are used. The existing rail noise levels at the project site were calculated using a proprietary software program based on Federal Rail Administration methodology. Because Coaster trains stop at the Carlsbad station (Amtrak and freight trains do not), which is located approximately 1,300 feet west of the site, it was assumed the average speed through the area is 35 miles per hour. It was assumed that each passenger train has one locomotive and 10 rail cars. For freight trains it was assumed they have two locomotives and 50 cars. Train warning horns were audible during monitoring; thus, it was assumed that train operators do use the warning horn when in proximity to the site. Of the 50 train pass by events each day, five freight operations were assumed to occur during the nighttime (10:00 p.m. to 7:00 a.m.) hours. Based on these assumptions, the exterior CNEL at the project site (located 2,000 feet west of the rail corridor) is approximately 49.1 dBA when both passenger and freight rail operations are combined. The estimated CNEL is less than measured background noise and generally appears consistent with CNEL contours provided in the 2015 General Plan Update Noise Element for residential areas within the City of Carlsbad. Rail operation would not exceed the recommended CNEL (65- dBA) for commercial uses. Interior Railroad Noise. The existing exterior CNEL at the site does not exceed the standard recommended by the City of Carlsbad for commercial uses. Design features associated with the project would reduce interior noise levels to at least 45 dBA CNEL as specified in the City of Carlsbad Noise Guidelines Manual for sensitive land uses (i.e., residences). As noted above, the proposed project would be designed to meet or exceed California Energy Code Title 24 standards which specify construction methods and materials that result in energy efficient structures and up to a 30 dBA reduction in exterior noise levels (assuming windows are closed). @O© BIRDSEYE PLANNING GROUP Grand and Hope Medical Office Building Project Noise Study 18 City of Carlsbad Assuming windows are closed, the CNEL associated with rail noise would be well below background noise levels. No measures in addition to compliance with Title 24 design requirements would be necessary to reduce interior rail noise. Rail Vibration. As noted, the proposed project would be constructed approximately 2,000 feet east of the rail corridor. Thus, a screening evaluation of potential vibration impacts was performed to determine whether the project would be exposed to vibration levels that could be perceived by tenants. Because the project is a medical office building, it would be considered a Category 3 land use for the purposes of vibration assessment as defined in the Federal Transit Administration, Transit Noise and Vibration Impact Assessment (2018). This category covers commercial uses where activities may be sensitive to vibration (i.e., medical office buildings). The impact criteria for a Category 3 land use is 78 VdB along corridors where train vibration events occur occasionally (i.e., 30 to 70 events daily). As noted, a vibration velocity of 75 VdB is the approximate dividing line between barely perceptible and distinctly perceptible levels. A screening level evaluation was performed to determine the likelihood of vibrations from the LOSSAN corridor affecting the proposed project. The screening distance for conventional commuter railroads was used to account for both passenger and freight trains. The distance between a conventional commuter railroad and Category 3 land use where the potential for a vibration impact to occur is 200 feet as defined in Table 9.2 within the FTA noise and vibration impact assessment methodology. The screening distances include a 5-decibel safety factor. The proposed project site is located outside the 200-foot screening distance; however, a general vibration assessment was performed to provide a more detailed evaluation of potential vibration impacts. The general vibration assessment methodology is provided in Chapter 10 of the assessment manual identified above. It is based on the use of a base curve to determine vibration as a function of distance from the track assuming a standard rail and ballast configuration. Using the diesel powered locomotive powered passenger or freight base curve (see Figure 10-1 in the Federal Transit Administration, Transit Noise and Vibration Impact Assessment Manual), the vibration level is 67.0 VdB at approximately 300 feet from the track at a reference speed of 50 miles per hour. This is likely conservative given the amount of ballast rock in the track bed and soil propagation; however, vibration from rail operation would not be perceptible at a distance of 2,000 feet from the source. The 72 VdB threshold would not be exceeded at the project site. Heating, Ventilation and Air Conditioning. The HVAC system proposed for use on the site has not been specified and noise levels vary depending on the size of the system. However, a total of seven HVAC units will be located on the roof. Two units will be located on the northern portion of the roof and the remaining five units will be located on the southern portion of the roof. Based on the proposed location and orientation, the two clusters are considered separate sources for the purpose of estimating noise levels off-site. Reference noise levels for the project are based on noise measurements made at similar facilities. HVAC noise levels can be expected @O© BIRDSEYE PLANNING GROUP Grand and Hope Medical Office Building Project Noise Study 19 City of Carlsbad to range from 60 to 70 dBA at 5 feet from the equipment and ventilation openings. To conservatively evaluate HVAC noise levels, the Leq was predicted at the western property line based on the distance between the sources and the east facing multifamily residences to the west. It is assumed the HVAC units would be an average of 30 feet east of the western property line. The sound level generated by the two northern units would attenuate to 57 dBA at the western property line which is similar to measured ambient conditions shown above in Table 2. The southern units would attenuate to approximately 61 dBA at the western property line. Each HVAC unit would be installed within a noise shroud which typically provides 5-10 dBA of attenuation. Conservatively, HVAC noise levels at the western property line would be approximately 52 dBA at the northern end and 56 dBA at the southern end. Thus, noise levels at east facing residential receivers to the west would be similar to measured ambient conditions and less than the 60 dBA residential standard. The building parapet would provide an additional 5 dBA of attenuation for the first and second floor residential units. This would further reduce HVAC noise to 47 dBA and the north end and 51 dBA at the southern end of the proposed building. Noise levels would be less than the 60 dBA residential at all units and inaudible over ambient noise at the east facing first and second floor units. @O© BIRDSEYE PLANNING GROUP Grand and Hope Medical Office Building Project Noise Study 20 City of Carlsbad References City of Carlsbad. General Plan Update Noise Element. 2015. City of Carlsbad. Noise Guidelines Manual. September 1995. City of San Diego. San Diego Trip Generation Manual, Land Development Code, May 2003. Federal Highway Administration. Roadway Construction Noise Model. 2006. Users Guide Table 1. Federal Highway Administration, Transportation Noise Model Version 2.5, 2004. Federal Transit Administration. Transit Noise and Vibration Impact Assessment Manual. September 2018. Federal Rail Administration (FRA) Guidelines (Report Number 293630-1), December 1998. Institute of Transportation Engineers (ITE) publication Trip Generation, 11th Edition @O© BIRDSEYE PLANNING GROUP Appendix A Appendix A Monitoring Data Sheet @O© BIRDSEYE PLANNING GROUP Grand and Hope Site 1 Start Date 5/24/2023 Start Time 2:59:42 PM End Time 3:14:41 PM Duration 00:14:59 Meas Mode Single Input Range Low Input Type Mic SPL Time Weight Slow LN% Freq Weight dBA Overload No UnderRange No Sensitivity 18.44mV/Pa LZeq 70.4 LCeq 67.5 LAeq 54.7 LZSmax 87.3 LCSmax 87.1 LASmax 73.4 LZSmin 63.0 LCSmin 59.5 LASmin 46.0 LZE 99.9 LCE 97.0 LAE 84.2 LZpk 97.1 LCpk 96.6 LApk 86.2 LAS1% 63.6 LAS2% 61.8 LAS5% 60.0 LAS8% 58.7 LAS10% 57.8 LAS25% 53.8 LAS50%51.1 LAS90% 48.1 LAS95% 47.6 LAS99% 46.5 Grand and Hope Site 2 Start Date 6/6/2023 Start Time 6:59:39 AM End Time 7:14:38 AM Duration 00:14:59 Meas Mode Single Input Range Low Input Type Mic SPL Time Weight Slow LN% Freq Weight dBA Overload No UnderRange No Sensitivity 18.44mV/Pa LZeq 66.9 LCeq 63.9 LAeq 52.1 LZSmax 76.2 LCSmax 75.1 LASmax 67.3 LZSmin 61.5 LCSmin 58.5 LASmin 45.4 LZE 96.4 LCE 93.4 LAE 81.6 LZpk 89.1 LCpk 87.0 LApk 84.5 LAS1% 62.0 LAS2% 59.3 LAS5% 56.1 LAS8% 54.6 LAS10% 53.7 LAS25% 51.4 LAS50%49.9 LAS90% 47.4 LAS95% 46.6 LAS99% 45.9 RESULTS: SOUND LEVELS <Project Name?> <Organization?> 20 November 2023 <Analysis By?> TNM 2.5 Calculated with TNM 2.5 I RESULTS: SOUND LEVELS PROJECT/CONTRACT: <Project Name?> RUN: Grand and Hope Existing BARRIER DESIGN: INPUT HEIGHTS Average pavement type shall be used unless a State highway agency substantiates the use ATMOSPHERICS: 68 deg F, 50% RH of a different type with approval of FHWA. Receiver Name No. #DUs Existing No Barrier With Barrier LAeq1h LAeq1h Increase over existing Type Calculated Noise Reduction Calculated Crit'n !Calculated Crit'n Impact LAeq1h Calculated Goal Calculated Sub'I Inc minus Goal dBA dBA dBA dB dB dBA dB dB dB Receiver1 1 1 0.0 52.6 66 52.6 10 ----52.6 0.0 8 -8.0 Receiver2 2 1 0.0 52.6 66 52.6 10 ----52.6 0.0 8 -8.0 Receiver3 3 1 0.0 53.1 66 53.1 10 ----53.1 0.0 8 -8.0 Receiver4 4 1 0.0 54.6 66 54.6 10 ----54.6 0.0 8 -8.0 Dwelling Units #DUs Noise Reduction Min Avg Max dB dB dB All Selected 4 0.0 0.0 0.0 All Impacted 0 0.0 0.0 0.0 All that meet NR Goal 0 0.0 0.0 0.0 C:\TNM25\Program\Grand and Hope 1 20 November 2023 RESULTS: SOUND LEVELS <Project Name?> <Organization?> 20 November 2023 <Analysis By?> TNM 2.5 Calculated with TNM 2.5 I RESULTS: SOUND LEVELS PROJECT/CONTRACT: <Project Name?> RUN: Grand and Hope With Project BARRIER DESIGN: INPUT HEIGHTS Average pavement type shall be used unless a State highway agency substantiates the use ATMOSPHERICS: 68 deg F, 50% RH of a differnnt type with approval of FI-IWA. Receiver Name No. #DUs Existing No Barrier With Barrier LAeq1h LAeq1h Increase over existing Type Calculated Noise Reduction Calculated Crit'n Calculated Crit'n Impact LAeq1h Calculated Goal Calculated Sub'I Inc minus I Goal dBA dBA dBA dB dB dBA dB dB dB Receiver1 1 1 0.0 53.7 66 53.7 10 ----53.7 0.0 8 -8.0 Receiver2 2 1 0.0 53.7 66 53.7 10 ----53.7 0.0 8 -8.0 Receiver3 3 1 0.0 53.7 66 53.7 10 ----53.7 0.0 8 -8.0 Receiver4 4 1 0.0 55.3 66 55.3 10 ----55.3 0.0 8 -8.0 Dwelling Units #DUs Noise Reduction Min Avg Max dB dB dB All Selected 4 0.0 0.0 0.0 All Impacted 0 0.0 0.0 0.0 All that meet NR Goal 0 0.0 0.0 0.0 C:\TNM25\Program\Grand and Hope With Project 1 20 November 2023