Noise Information
The Department of Environment and Conservation (DEC) regulate noise emissions in Western Australia through the Environmental Protection (Noise) Regulations 1997 (Noise Regulations). The Noise Regulations set noise limits to ensure that noise received at premises is kept to an acceptable level. The basis for the assigned levels (noise limits) within the Noise Regulations is the land use where the noise is received. This method recognises and protects the quiet surroundings people enjoy, whilst recognising the influence of industry, commerce and transport on the noise environment. The assigned noise levels are the levels of noise allowed to be received at a premise at a particular time of the day or night. These assigned levels are adjusted based on the proximity to industrial, commercial area and major roads.
In a location such as the future Baldivis Substation, the substation must be constructed to comply with an assigned level of 35dB(A) at night and 45dB(A) during the day at the property boundary of all the affected noise-sensitive premises (residential properties in this case). Given that noise reduces as the distance increases from the noise source, only properties directly adjacent to the substation will receive the maximum noise level of 35dB(A). A noise level of 35dB(A) is equivalent to the noise observed within a library.
Given the proposed future residential development around the Baldivis Substation, noise mitigation will be required to reduce the noise emissions from the substation to comply with the Noise Regulations. The noise mitigation techniques available for the Baldivis Substation include solid boundary walls, large earth mounds or enclosures/walls around the transformers. These noise mitigation options will need to be evaluated taking into account: (1) requirements of site security, (2) technical constraints, (3) visual amenity, (4) future maintenance issues and (5) costs. The selected mitigation technique will achieve compliance with the Noise Regulations and then be incorporated into the overall design. This may reduce the noise levels received at adjacent residential premises to below the required night-time assigned level (35dB(A)). A noise assessment will be conducted once the substation design has been finalised to confirm the requirements for, and effectiveness of, noise mitigation options. A noise assessment will also be completed once the substation is operational.
The Noise Regulations are designed to provide a 'fair and reasonable' level of noise at all premises, based on the location. Therefore, complying with the Noise Regulations will provide 'a fair and reasonable' level of noise at all premises surrounding the substation. The noise levels we are talking about at the property boundary is equivalent to the background levels of noise found in a library. It has been estimated that inside the house levels would be at least another 5dB(A) quieter.
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