HGC Engineering was retained to perform a noise impact study for a Wal-Mart Store Expansion in Brantford, Ontario. The analysis included an assessment of the noise impact of the existing retail store and the proposed expansion at the south and east ends of the store on existing adjacent residences, in accordance with Ministry of the Environment (MOE) guidelines. The study is required as part of the approvals process in the City of Brantford.
The commercial site on which the Wal-mart store is located includes a Cinema Complex, Dollar Store, Beer Store and other retail uses. Only the existing Wal-mart store and proposed expansion were considered in the analysis.
The Wal-mart site is located in a Class 1 (urban) acoustical environment where the background sound is primarily made up of the sounds of road traffic and human activity (urban hum) in both the daytime and nighttime hours.
Noise Source Description
The lands to the north and east of the site are existing residential lands. There are existing 1½ storey residences to the northwest, a two-storey apartment building to the north, and two-storey residences to the northeast and southeast of the Wal-mart store.
Sources of sound associated with Wal-mart stores are rooftop mechanical equipment, the outdoor garbage compactor and trucking activities. Trucking activities generally include brief accelerations, idling at loading bays and refrigeration equipment on some trailers. Roof plans and specifications for the existing and proposed rooftop mechanical equipment were provided for analysis.
Stationary Noise Criteria
In Ontario, the guidelines of the Ontario Ministry of the Environment (MOE) form the basis of environmental noise assessment. MOE publication NPC-205, Sound Level Limits For Stationary Sources in Class 1 & 2 Areas (Urban), provides criteria for assessing the noise impact of this commercial facility. The term Stationary Source is used to designate all noise sources associated with the facility, including mechanical equipment and conveyances, such as trucks, when they are moving within the site boundaries.
MOE guidelines specifically exempt sounds from certain commercial activities, such as the occasional delivery of goods and services using small vehicles (couriers, vans etc.), garbage collection and customer vehicles. Accordingly, these sources were considered in this study. Noise from safety equipment (e.g. back-up beepers) is also exempt from consideration.
The MOE guidelines criteria are based on the background at sensitive points of reception (which are typically residences) in the quietest hour that the source can be in operation. Background sound includes sound from road traffic and natural sounds, but excludes the sources under assessment.
The MOE guidelines stipulate that the sound level impact during a “predicable worst case hour” be considered. This is defined to be an hour when a typically busy “planned and predictable mode of operation” occurs at the subject facility coincident with a period of minimal background sound.
Sound Level Measurements and Observations
A site visit was performed to investigate the site to make observations of the existing residential dwellings and to measure ambient sound levels near the subject site during daytime hours.
HGC Engineering predicted the worst-case impacts of the operations of the expanded Wal-mart at the existing residential receptors with respect to MOE guidelines.
Mitigation in the form of an acoustic enclosure with garage doors for the loading area, extension of the existing acoustic barrier on the north property line towards the west, roof screens for some of the A/C units and the north end of the building were deemed to be required. With these recommendations implemented, it was anticipated that noise sources associated with the Wal-mart store and expansion would meet the MOE guidelines at each of the residential receptors.
Acoustical Engineering Services Included:
- Conducted detailed noise sudies in accordance with Ontario Ministry of the Environment procedures
- Specified noise controls
- Developed noise control plan