Stationary Noise Assessment. Car Dealership Strandherd Drive. Ottawa, Ontario

Transcription

1 Stationary Noise Assessment Car Dealership Strandherd Drive Ottawa, Ontario REPORT: GWE Noise Prepared For: Lewis Treimstra 1805 Woodward Drive Ottawa, Ontario K2C 0P9 Prepared By: Michael Lafortune, Environmental Technologist Joshua Foster, P.Eng., Associate December 3, Walgreen Road, Ottawa, Ontario K0A 1L0 T (613) F (613)

2 EXECUTIVE SUMMARY This document describes a stationary noise study performed for site plan approval of a proposed commercial development consisting of a two-storey car dealership in Ottawa, Ontario. The building will rise approximately 7.6 meters above local grade. The site is located near the intersection of Strandherd Drive and Kennevale Drive. Figure 1 illustrates a site plan with surrounding context. The assessment is based on: (i) theoretical noise prediction methods that conform to the Ministry of the Environment and Climate Change (MOE) and City of Ottawa requirements; (ii) noise level criteria as specified by the City of Ottawa s Environmental Noise Control Guidelines (ENCG); (iii) architectural drawings provided by Leonard Hoffman Architect. Our stationary noise assessment for a car dealership on Strandherd Drive indicates that provided equipment selections and locations are similar to the assumptions in this report, noise levels at nearby points of reception are expected to fall below the City of Ottawa (ENCG) noise criteria. Since the noise levels are well below ENCG criteria, the proposed development is expected to be compatible with the existing noise sensitive land uses. As this study is based on preliminary mechanical information, final mechanical equipment selection and locations should be reviewed by an acoustical engineer prior to installation of the equipment. Strandherd Car Dealership: Stationary Noise Study i

3 TABLE OF CONTENTS PAGE 1. INTRODUCTION 1 2. TERMS OF REFERENCE Assumptions 1 3. OBJECTIVES 2 4. METHODOLOGY Perception of Noise Stationary Noise Criteria Determination of Noise Source Power Levels Stationary Source Noise Predictions 4 5. RESULTS AND DISCUSSION 5 6. CONCLUSIONS AND RECOMMENDATIONS 6 FIGURES Strandherd Car Dealership: Stationary Noise Study ii

4 1. INTRODUCTION Gradient Wind Engineering Inc. (GWE) was retained by to perform a stationary noise study for site plan approval (SPA) of a proposed commercial development consisting a two-storey car dealership at 4123 Strandherd Drive in Ottawa, Ontario. This report focuses on the noise impacts from rooftop mechanical equipment on nearby residential areas. This study is based on architectural drawings provided by Leonard Hoffman Architect, surrounding street layouts obtained from the City of Ottawa and recent site imagery. 2. TERMS OF REFERENCE The site is located near the intersection of Strandherd Drive and Kennevale Drive, and is surrounded by a mix of residential and business park industrial lands on all sides. The closest points of reception are residential housing to the east of the development. Figure 1 illustrates the site plan and surrounding context. The development is a car dealership consisting of a two-storey retail building rising approximately 7.6 meters (m) above local grade. The expected operating hours of the business are during daytime hours, between 7:00 AM and 11:00 PM. Figure 2 illustrates the location of all mechanical equipment for the Strandherd car dealership building. 2.1 Assumptions Mechanical information for the development has not yet been finalized and therefore assumptions were made to best represent what the final configuration might resemble. A review of final equipment selection and locations by a qualified acoustical engineer will be required prior to installation of the equipment. The following assumptions have been included in the analysis: (i) The quantity, location, and sound power of the mechanical equipment has been approximated based off a previous Orleans car dealership development roof plan (ii) All rooftop units are assumed to operate continuously during the daytime period and for 30 minutes per hour during the nighttime period (iii) All exhaust fans are assumed to operate continuously during the daytime period and for 30 minutes per hour during the nighttime period (iv) All compressor units are assumed to operate continuously during the daytime period and for 30 minutes per hour during the nighttime period Strandherd Car Dealership: Stationary Noise Study 1

5 3. OBJECTIVES The main goals of the work are to assess the anticipated noise impacts from rooftop mechanical equipment on nearby sensitive receptors, and describe noise control measures to ensure the development can operate in the area compliant to the City of Ottawa s Environmental Noise Guidelines (ENCG). 4. METHODOLOGY The impact of the external stationary noise sources on the nearby residential areas was determined by computer modelling. Stationary noise source modelling is based on the software program Predictor- Lima developed from the International Standards Organization (ISO) standard 9613 Parts 1 and 2. This computer program is capable of representing three-dimensional surfaces and first reflections of sound waves over a suitable spectrum for human hearing. The methodology has been used on numerous assignments, and has been accepted by the Ministry of Environment and Climate Change (MOE) as part of Environmental Compliance Approvals applications. Four receptor locations were chosen around the site, as illustrated in Figure Perception of Noise Noise can be defined as any obtrusive sound. It is created at a source, transmitted through a medium, such as air, and intercepted by a receiver. Noise may be characterized in terms of the power of the source or the sound pressure at a specific distance. While the power of a source is characteristic of that source, the sound pressure depends on the location of the receiver and the path that the noise takes to reach the receiver. Its measurement is based on the decibel unit, dba, which is a logarithmic ratio referenced to a standard noise level ( Pascals). The A suffix refers to a weighting scale, which represents the noise perceived by the human ear. With this scale, a doubling of sound power at the source results in a 3 dba increase in measured noise levels at the receiver, and is just perceptible to most people. An increase of 10 dba is often perceived to be twice as loud. Stationary sources are defined in the City of Ottawa Environmental Noise Control Guide as: all sources of sound and vibration, whether fixed or mobile, that exist or operate on a premises, property or facility. The combined sound and vibration levels of which are emitted beyond the property boundary of the premises, property or facility, unless the source(s) is (are) due to construction. Strandherd Car Dealership: Stationary Noise Study 2

6 4.2 Stationary Noise Criteria The equivalent sound energy level, L EQ, provides a weighted measure of the time varying noise levels, which is well correlated with the annoyance of sound. It is defined as the continuous sound level, which has the same energy as a time varying noise level over a selected period of time. For stationary sources, the L EQ is commonly calculated on an hourly interval, while for roadways, the L EQ is calculated on the basis of a 16-hour daytime / 8-hour nighttime split. Noise criteria taken from the ENCG apply to outdoor points of reception (POR). A POR is defined under ENCG as any location on a noise sensitive land use where noise from a stationary source is received. A POR can be located on an existing or zoned for future use premises of permanent or seasonal residences, hotels/motels, nursing/retirement homes, rental residences, hospitals, camp grounds, and noise sensitive buildings such as schools and places of worship. According to the ENCG, the recommended maximum noise levels for a Class 2 area in an urban environment at a POR are outlined in Table 1 below. TABLE 1: EXCLUSIONARY LIMITS FOR CLASS 2 AREA Time of Day Outdoor Points of reception Plane of Window 7:00 19: :00 7: Determination of Noise Source Power Levels Sound power data for the rooftop units, exhaust fans and compressor unit were provided by Dilfo Mechanical Limited, and are based on a similar dealership in Orleans. Table 2 summarizes the sound power of each source assumed in our analysis. Strandherd Car Dealership: Stationary Noise Study 3

7 Source ID Description TABLE 2: EQUIPMENT SOUND POWER LEVELS (dba) Frequency (Hz) Total S1 RTU-6 N/A N/A N/A N/A 94 N/A N/A N/A 94 S2 RTU-5 N/A N/A N/A N/A 94 N/A N/A N/A 94 S3 RTU-4 N/A N/A N/A N/A 82 N/A N/A N/A 82 S4 RTU-3 N/A N/A N/A N/A 75 N/A N/A N/A 75 S5 EF S6 EF S7 EF S8 RTU-7 N/A N/A N/A N/A 67 N/A N/A N/A 67 S9 RTU-2 N/A N/A N/A N/A 61 N/A N/A N/A 61 S10 RTU-1 N/A N/A N/A N/A 72 N/A N/A N/A 72 S11 EF S12 EF S13 EF S14 EF S15 Compressor Inlet N/A N/A N/A N/A 80 N/A N/A N/A Stationary Source Noise Predictions Four individual noise sensor locations were selected in the Predictor-Lima model to measure the noise impact at points of reception (POR) during the daytime (7:00 AM 7:00 PM) and nighttime (7:00 PM 7:00 AM) periods. POR locations included the outdoor living areas (OLA) and the plane of windows (POW) of the residential properties surrounding the study site. Sensor locations are described in Table 3 and illustrated in Figure 3. All units were represented as point sources in the Predictor model. Air temperature, pressure and humidity were assumed 10 C, kpa and 70%, respectively. Ground absorption over the study area was determined based on topographical features (such as water, concrete, grassland, etc.). An absorption value of 0 is representative of hard ground, while a value of 1 represents grass, and similar soft surface conditions. Existing and proposed buildings were added to the model to account for screening and reflection effects from building façades. Strandherd Car Dealership: Stationary Noise Study 4

8 Receptor Number TABLE 3: RECEPTOR LOCATIONS Location Height Above Grade (m) R1 OLA 245 Kennevale Drive 1.5 R2 POW 549 Simran Private 7.5 R3 POW 576 Simran Private 7.5 R4 POW 458 Sadar Private RESULTS AND DISCUSSION Unmitigated noise levels at nearby sensitive receptors appear below ENCG criteria as shown in Table 4. The sound levels listed in Table 4 assume the worst-case scenario; all mechanical equipment is at full operation during the daytime period, including the shop compressor. Receptor Number TABLE 4: UNMITIGATED NOISE LEVELS FROM STATIONARY SOURCES Plane of Window Receptor Location 1-HR L eq (dba) ENCG Criteria (dba) Day Night Day Night Meets ENCG 1 OLA 245 Kennevale Drive Yes 2 POW 549 Simran Private Yes 3 POW 576 Simran Private Yes 4 POW 458 Sadar Private Yes As Table 4 summarizes, noise levels are well below ENCG criteria. This is a result of the distance between the dealership, and nearby sensitive areas. Noise contours at 7.5 m above grade can be seen in Figure 4 and Figure 5 for daytime and nighttime conditions respectively. The main contributors of noise at these locations are the rooftop units RTU-5 and RTU-6 located on the eastern side of the dealership, nearest to the receptors. Since the noise levels are well below ENCG criteria, the proposed development is expected to be compatible with the existing noise sensitive land uses. If future studies show that noise levels exceed ENCG criteria, there are a number of control measures available to reduce noise levels. These include; noise screens/enclosures, silencers, and/or selection of quieter equipment. Strandherd Car Dealership: Stationary Noise Study 5

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13 FIGURE 4: DAYTIME NOISE CONTOURS (7.5 METERS ABOVE GRADE) db db db db db db db db db db 0 35 db Strandherd Car Dealership: Stationary Noise Study 7

14 FIGURE 5: NIGHTTIME NOISE CONTOURS (7.5 METERS ABOVE GRADE) db db db db db db db db db db 0 35 db Strandherd Car Dealership: Stationary Noise Study 8