Environmental Noise (and Vibration) can over a multitude of areas, from Complaints and Compliance to Impact Assessments and Modelling.
The definition of 'noise' as 'unwanted sound' implies that the tolerance of an activity can depend on the perspective - one person's 'sound' is another person's noise in other words.
There are also some potentially significant health effects associated with long-term exposure to elevated noise levels.
Often environmental noise is a comparison of baseline conditions with the noise level of the activity in question e.g. impact assessment for new developments. Various national and international guidance assist the acoustician in a balanced assessment, however, while every effort is made for objective evaluation, there is often scope for interpretation.
PlanningThe Department of Housing, Local Government and Heritage (DHLGH) provides planning guidelines and planning exemptions for wind farms and wind turbines - the Wind Energy Development Guidelines (WEDG06). These set a general lower fixed limit at nearby noise sensitive locations of: 45dB(A) or; a maximum increase of 5dB(A) above background noise In low noise environments it recommends a daytime LA90, 10min level between 35-40dB(A). The UK's ETSU-R-97 “The Assessment and Rating of Noise from Wind Farms” and the Institute of Acoustics Good Practice Guides are currently the preferred method of assessing wind farm noise for planning purposes and are used to supplement the guidance contained within the WEDG06. The WEDG-06 guidelines are currently under review and the draft guidelines include proposed new standards aimed at reducing noise nuisance.
ComplianceA planning condition for post-installation noise monitoring is often required. This is usually a long-term programme perhaps up to 12months. The draft WEDG guideline require that planning authorities should impose planning conditions in relation to noise limits and deveopers conduct noise monitoring in accordance with the IoA GPG Supplementary Guidance Note 5: Post Completion Measurements.
Structural Health MonitoringBy performing long-term continuous Structural Health Monitoring (SHM) it is possible to monitor and track a structure’s state and carry out condition-based maintenance to ensure structural integrity. On a wind turbine blade, we can detect damage, locate it, and follow its progression. To find out more, check out these couple of videos on solutions from HBK: Structural Health Monitoring of Wind Turbine blades. Predictive Structural Health Monitoring of Wind Turbine blades.
ReferencesIWEA 2022 annual report. Wind Energy Development Guidelines (WEDG06) Draft Wind Energy Development Guidelines (2019) Institute of Acoustics Good Practice Guides DCCAE: Department of Communication, Climate Change, and Environment's website has information on the future role for wind energy in Ireland and the new Renewable Electricity Support Scheme (RESS). Structural Health Monitoring