Stationary Noise Feasibility Study. The Shops of Tenth Line. Ottawa, Ontario

Size: px
Start display at page:

Download "Stationary Noise Feasibility Study. The Shops of Tenth Line. Ottawa, Ontario"

Transcription

1 Stationary Noise Feasibility Study The Shops of Tenth Line Ottawa, Ontario REPORT: GWE Stationary Noise Prepared For: Jeff Parks 225 Metcalfe Street Ottawa, Ontario K2P 1P9 Prepared By: Thomas Couper, B.A.Sc., Project Manager Joshua Foster, P.Eng., Associate Gradient Wind Engineering Inc. June 25, Walgreen Road, Ottawa, Ontario K0A 1L0 T (613) F (613)

2 EXECUTIVE SUMMARY Our stationary noise feasibility assessment for The Shops at Tenth Line indicates that provided our recommendations are considered in the detailed design process, noise levels at nearby points of reception are expected to fall below the City of Ottawa and Ministry of the Environment (MOE) noise criteria. Assuming the worst-case scenario, the noise impacts from the loading docks and mechanical equipment can be mitigated as outlined in Section 5. As such, the proposed development is expected to be compatible with the existing noise sensitive land uses. The Shops at Tenth Line: Stationary Noise Assessment 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 5 5. RESULTS AND DISCUSSION 6 6. CONCLUSIONS 9 FIGURES The Shops at Tenth Line: Stationary Noise Assessment ii

4 1. INTRODUCTION Gradient Wind Engineering Inc. (GWE), formerly Gradient Microclimate Engineering Inc. (GME), was retained by to perform a stationary noise feasibility study for a future commercial development located at 2272 Tenth Line Road in Ottawa, Ontario. This report focuses on the noise impacts from two loading docks and rooftop mechanical equipment. This study is based on architectural drawings provided by Barry J. Hobin & Associates Architects Inc., dated April, 2014, surrounding street layouts obtained from the City of Ottawa and recent site imagery. 2. TERMS OF REFERENCE The site is located on the west corner of Brian Coburn Boulevard and Tenth Line Road, and is surrounded by a mix of residential and undeveloped lands on all sides. The closest points of reception are residential housing to the west behind the development. Figure 1 illustrates the site plan and surrounding context. The development consists of seven single-storey retail buildings. The Sobeys grocery store will have two loading docks, while The Beer Store will have one. The expected operating hours of the businesses are during daytime hours, between 7:00 AM and 11:00 PM. It is expected that the Sobeys will operate 24 hours a day. Figure 2 illustrates the location of the loading docks and other noise sources. 2.1 Assumptions The following assumptions have been included in the analysis: (i) (ii) (iii) Frequent deliveries using refrigerated trucks occur at each Sobeys loading dock Refrigerated truck deliveries do not take place during the overnight period (7:00 PM 7:00 AM) Although truck deliveries can take up to 1 hour in duration, reefer units will only operate for a total of 30 minutes during any 1 hour period (iv) The Sobeys rooftop unit (60-ton) is assumed to operate continuously during the daytime period and for 30 minutes per hour during the nighttime period (v) The location of the mechanical equipment at Sobeys has been approximated based off previous Sobeys developments (vi) The generator at Sobeys is assumed to operate continuously during daytime and nighttime periods The Shops at Tenth Line: Stationary Noise Assessment Page 1

5 (vii) As The Beer Store receives infrequent refrigerated truck deliveries, their loading dock is considered an insignificant source of noise, and has therefore not been included in this study (viii) (ix) The location and sound power for the rooftop units at the remaining stores has been assumed The rooftop mechanical units at the remaining stores are assumed to operate continuously during daytime and nighttime periods 3. OBJECTIVES The main goals of the work are to assess the anticipated noise impacts from idling refrigerated trucks and rooftop mechanical equipment on nearby sensitive receptors to ensure the development can feasibly operate in the area. 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 MOE as part of Environmental Compliance Approvals applications. Thirteen 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 Shops at Tenth Line: Stationary Noise Assessment Page 2

6 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. 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 Ministry of the Environment NPC-300 apply to outdoor points of reception (POR). A POR is defined under NPC-300 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. The City of Ottawa has also set similar noise guidelines outlined in their document Environmental Noise Control Guidelines (ENCG). According to this document, based on MOE s NPC-205, the recommended maximum noise levels for a Class 2 area in an urban environment at a POR are: 50 dba between 7:00 AM and 7:00 PM 45 dba between 7:00 PM and 7:00 AM Alternately the noise produced by roadway traffic, whichever is greater As the residential properties are shielded from Tenth Line Road by the development, the MOE exclusionary limits have been applied. 4.3 Determination of Noise Source Power Levels Sound power data for the condenser, generator and rooftop air units at Sobeys were provided by Taggart, and are based off existing Sobeys outlets. The rooftop mechanical equipment at the remaining retail outlets has been assumed from other similar commercial developments. Sound pressure data from Carrier were obtained to represent the reefer units at each loading dock, specifically 76 dba at 7 meters. A sound pressure of this amount yields a sound power of 101 dba. Each reefer was assumed to operate 2.2 meters above grade (including the decline of the loading bay ramp). Table 1 summarizes the sound power of each source used in the analysis. The Shops at Tenth Line: Stationary Noise Assessment Page 3

7 Source ID Description TABLE 1: EQUIPMENT SOUND POWER LEVELS (dba) Frequency (Hz) Total S1 S22 Air Handling Unit (assumed) N/A N/A N/A N/A 82 N/A N/A N/A 82 S23 Exhaust Fan N/A N/A N/A N/A 64 N/A N/A N/A 64 S24 Condenser (6 Cell) N/A N/A N/A N/A 84 N/A N/A N/A 84 S25 Condenser (8 Cell) N/A N/A N/A N/A 86 N/A N/A N/A 86 S26 Exhaust Fan N/A N/A N/A N/A 64 N/A N/A N/A 64 S27 Exhaust Fan N/A N/A N/A N/A 58 N/A N/A N/A 58 S28 Return Air Unit (60-Ton) S29 Exhaust Fan N/A N/A N/A N/A 67 N/A N/A N/A 67 S30 Exhaust Fan N/A N/A N/A N/A 61 N/A N/A N/A 61 S31 Exhaust Fan N/A N/A N/A N/A 72 N/A N/A N/A 72 S32 Exhaust Fan N/A N/A N/A N/A 64 N/A N/A N/A 64 S33 Return Air Unit S34 Return Air Unit S35 Exhaust Fan N/A N/A N/A N/A 60 N/A N/A N/A 60 S36 Exhaust Fan N/A N/A N/A N/A 67 N/A N/A N/A 67 S37 Exhaust Fan N/A N/A N/A N/A 66 N/A N/A N/A 66 S38 Refrigerated Truck N/A N/A N/A N/A 101 N/A N/A N/A 101 S39 Refrigerated Truck N/A N/A N/A N/A 101 N/A N/A N/A 101 S40 Generator The Shops at Tenth Line: Stationary Noise Assessment Page 4

8 4.4 Stationary Source Noise Predictions Thirteen 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 property line and the plane of windows (POW) of the residential properties surrounding the study site. Sensor locations are described in Table 2 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. TABLE 2: RECEPTOR LOCATIONS Receptor Number Location Height Above Grade (m) R1 POW Montargis Circle 4.5 R2 OLA Montargis Circle 1.5 R3 POW Montargis Circle 4.5 R4 OLA Montargis Circle 1.5 R5 POW Montargis Circle 4.5 R6 OLA Montargis Circle 1.5 R7 POW Montargis Circle 4.5 R8 OLA Montargis Circle 1.5 R9 POW Montargis Circle 4.5 R10 OLA Montargis Circle 1.5 R11 POW Rochefort Circle 4.5 R12 OLA Rochefort Circle 1.5 R13 POW Louis Toscano Drive 4.5 The Shops at Tenth Line: Stationary Noise Assessment Page 5

9 5. RESULTS AND DISCUSSION Unmitigated noise levels at nearby sensitive receptors appear elevated, as summarized in Table 3 below, due to the close proximity of the loading docks and some rooftop mechanical equipment. The sound levels listed in Table 3 assume the worst-case scenario; each loading dock is regularly serviced by refrigerated trucks 24 hours a day. Since the generator is for emergency situations, it is has been assessed separately from the other mechanical equipment, as per NPC-300 guidelines. Receptor Number TABLE 3: UNMITIGATED NOISE LEVELS FROM STATIONARY SOURCES Plane of Window Receptor Location Generator Noise Level (dba) HVAC/Idling Truck Day Night Day Night 1 POW Montargis Circle OLA Montargis Circle POW Montargis Circle OLA Montargis Circle POW Montargis Circle OLA Montargis Circle POW Montargis Circle OLA Montargis Circle POW Montargis Circle OLA Montargis Circle POW Rochefort Circle OLA Rochefort Circle POW Louis Toscano Drive As Table 3 summarizes, noise levels are elevated at many receptors. The main contributors of noise at these locations are the idling refrigerated trucks in the loading dock and the rooftop mechanical units, specifically source S28 (60-ton roof top unit). Noise levels from the generator are elevated, as tabulated in Table 3. Since the generator is an emergency unit, the noise criteria in Section 4.2 can be increased by 5 db as outlined in NPC-300. Although the criteria have been increased, noise impacts from the generator are still above the limit. The Shops at Tenth Line: Stationary Noise Assessment Page 6

10 Cummins offers a sound enclosure, specifically F-217 Quite Site II Second Stage, which produces a total sound power level of 92.7 dba. Calculations were completed assuming the generator has the F-217 enclosure, with the results shown in Table 4 below. The results show that should the generator include this sound enclosure, noise levels at critical points of reception will be below the MOE criteria of 55 dba daytime and 50 dba nighttime. TABLE 4: NOISE IMPACTS FROM GENERATOR (WITH SOUND ENCLOSURE) Receptor Number Plane of Window Receptor Location Noise Level (dba) Day Night 1 POW Montargis Circle OLA Montargis Circle POW Montargis Circle Noise levels at POR 9 are elevated due to the idling refrigerated trucks in the loading dock. Investigation into constructing a 33-meter long, 6.5-meter high solid wall beside the loading dock proved that noise levels can be reduced below the ENCG guideline of 50 dba daytime, see Figure 4. Table 5 summarizes the mitigated noise levels at POR s with the inclusion of a solid noise wall. In addition to the elevated noise from the idling trucks, the 60-ton rooftop mechanical unit at Sobeys (S28) elevates noise levels at various points of reception to the west. To reduce the noise impacts at these sensitive spaces, the following mitigation measures should be considered, as summarized in Table 5: Select a rooftop mechanical unit with a maximum sound power level of 88 dba Install a 2.5 meter noise screen along the north, south and west sides of the unit (Figure 4) The Shops at Tenth Line: Stationary Noise Assessment Page 7

11 Receptor Number TABLE 5: MITIGATED NOISE LEVELS FROM IDLING TRUCKS & HVAC EQUIPMENT Plane of Window Receptor Location HVAC/Idling Truck Noise Level (dba) No Wall With Solid Wall & Noise Screen Day Night Day Night 1 POW Montargis Circle OLA Montargis Circle POW Montargis Circle OLA Montargis Circle POW Montargis Circle OLA Montargis Circle POW Montargis Circle OLA Montargis Circle POW Montargis Circle OLA Montargis Circle POW Rochefort Circle OLA Rochefort Circle POW Louis Toscano Drive Includes source S28 operating at 88 dba All stores, excluding Sobeys, have been assumed to operate at least one rooftop mechanical unit with a sound power of 82 dba. The units were arbitrarily placed in the center of the roof. Noise impacts from these units do not exceed the ENCG limits, as outlined in Section 4.2. To ensure noise levels at sensitive receptors do not exceed the criteria, mechanical units with a maximum sound power of 82 dba should be selected. Since the elevated noise levels can be feasibly mitigated, the proposed development is expected to be compatible with the existing land uses. The Shops at Tenth Line: Stationary Noise Assessment Page 8

12

13

14

15

16