Location: Brampton, Ontario, Canada
Engineering: Trow Associates (now EXP)
Architect: Moffet & Duncan Architects
Contractor: M. J. Dixon Construction
Owner/Operator: City of Brampton
HGC Engineering was retained to undertake a noise impact feasibility study for a proposed Rapid Bus Transit Terminal that would serve Brampton Transit in the community of Bramalea. The study used predictive analysis to assess the potential impact of the Transit Terminal, with respect to the guidelines of the Ministry of Environment (MOE), which are accepted by the City of Brampton. The existing bus terminal located at the Bramalea City Centre was expected to be relocated to the subject site.
Site Description and Noise Sources
The proposed transit facility was to be located at the southwest corner of Peel Centre Drive and Central Park Drive in Brampton, Ontario. The Transit Terminal would include one administrative building with offices, a waiting area, two bus platforms with a total of 18 bays and a layover area. A living wall was proposed between the two bus platforms. The buses would access the site from Team Canada Drive (one entry/exit), Central Park Drive (two entries/exits) and Peel Centre Drive (one exit only)
HGC Engineering visited the site on numerous occasions to observe the existing background sound in the vicinity of the proposed development site and to perform sound level measurements at an existing transit facility (Bramalea City Centre Transit Terminal). The background sound levels at the proposed transit terminal were dominated by road traffic along Peel Centre Drive, Central Park Drive, Team Canada Drive, Kensingston Road and Queen Street. The area surrounding the subject site is best categorized as a Class 1 (urban) acoustical environment, under MOE noise assessment guidelines.
The subject site is bordered along the south by the existing Brampton Civic Centre, approximately 4 – 5 storeys in height. To the west is a Grocery Chain Store. To the north are two Region of Peel buildings, including a police station. At the northeast corner is a former police station which at the time of the assessment was vacant. There were hi-rise apartment buildings to the northeast and to the southeast The Bramalea City Centre is located to the further west of the subject site.
The most potentially impacted points of reception were dwelling units at an existing 2-storey apartment building located approximately 50 m to the east of the subject site.
The primary sources of sound associated with the transit terminal would be arriving, departing and idling buses. In addition, the study considered sound emitted by rooftop air conditioning (A/C) equipment associated with the proposed administration building.
In Ontario, the guidelines of the MOE form the basis of environmental noise assessment, specifically publication NPC-205, “Sound Level Limits For Stationary Sources in Class 1 & 2 Areas (Urban)”. The MOE guidelines draw a distinction between “stationary sources” (industrial or commercial sounds), and other types of sources such as traffic or construction activities, for example. The sound sources associated with the proposed transit terminal are classified as stationary sources. The guidelines for stationary sources are site specific and depend on the background sound in the vicinity due to road traffic. The guidelines also stipulate that the assessment consider the potential noise impact during a “predictable worst case hour” of operation, which is defined as a situation when the normally busy activity of the source coincides with an hour of low background sound.
Background Sound Levels
Because background sound in the vicinity of the closets receptor location was dominated by road traffic, the applicable limits were determined through prediction of road traffic noise. Traffic volume data for the adjacent roadways were obtained from the City of Brampton and an existing Traffic Impact Study.
This traffic data was extrapolated a year into the future using a 2.5% growth rate and applied to a generic 24 hour traffic pattern developed by the US Department of Transportation, Federal Highways Administration.
The traffic volumes were then used to predict sound levels at the residential receptors during the day/evening/nighttime hours to determine the hourly background sound levels at those locations due to the traffic on these public roadways including buses.
Discussions with Brampton Transit terminal personnel (at the existing Bramalea City Centre terminal) were conducted to determine the distribution of buses throughout the day/evening and nighttime hours.
Predictions of the background sound levels were made using STAMSON, a computer algorithm developed by the MOE. The background sound levels included the increased number of buses in the area due to the transit terminal.
Rooftop Mechanical Equipment
At the time of the assessment, rooftop mechanical equipment for the proposed administration building had not yet been selected. Preliminary roof plans indicated that three 4-ton rooftop units would likely be used for the building to meet the heating/cooling loads of the building,. The analysis also assumed that, while the rooftop units may run 100% of the time during a worst-case daytime or evening hour, such as on a very hot day in summer, the nighttime operation would be less.
The above analysis indicates that the predicted LEQ sound levels from the proposed Bramalea Rapid Bus Transit Terminal will be within MOE sound level limits during all hours of operation. Additional mitigation measures are not required.
Service Solutions Delivered:
- Prepared application
- Conducted detailed acoustical assessment reports and audits in accordance with Ontario Ministry of the Environment procedures
- Specified noise controls
- Developed noise control plan