Published: April 2017

The Ministry of the Environment and Climate Change (MOECC) is committed to ensuring that its policies and protocols regarding wind farms continue to reflect current science. Should new information come to light, the MOECC will review and amend its policies and protocols as required.

All requirements relating to Renewable Energy Approval (REA) applications and renewable energy projects are contained in Part V.0.1 of the Environmental Protection Act and O. Reg. 359/09, which can be found at Ontario’s e-Laws website or the official volumes printed by Publications Ontario for the authoritative text. Specific references to the Noise Guidelines for Wind Farms, Reference [4] as amended, are made throughout this protocol and readers are recommended to have access to a copy of the guideline itself to refer to the exact language when reading.

Ministry of the Environment and Climate Change
Public Information Centre:

E-mail: picemail.moe@ontario.ca
Website: Ministry of the Environment and Climate Change

Part A: General

A1 References

The following publications are referenced in this document:

  1. CAN/CSA-C61400-11-07, "Wind Turbine Generator Systems – Part 11: Acoustic Noise Measurement Techniques"
  2. ISO 1996-2, "Acoustics – Description, assessment and measurement of environmental noise – Part 2: Determination of environmental noise levels"
  3. ISO 9613-2, Acoustics – Attenuation of sound During Propagation Outdoors, Part 2: General Method of Calculation
  4. Noise Guidelines for Wind Farms – Interpretation for Applying MOECC NPC Publications to Wind Power Generating Facilities May 2016; PIBS number 9900e
  5. "Compliance Policy Applying Abatement and Enforcement Tools", May 2007, PIBS #6248, Ontario Ministry of the Environment, as amended
  6. CAN/CSA-IEC 61400-11:13, "Wind Turbines – Part 11: Acoustic Noise Measurement Techniques", Canadian Standards Association
  7. IEC 61672-1 (2002), "Electroacoustics – Sound level Meters, Part 1" Specifications
  8. IEC 60942: 2003, "Electroacoustics – Sound Calibrators"

A2 Definitions

For the purposes of this document, the following definitions apply:

"Abatement"
means voluntary or mandatory actions taken to achieve compliance.
"Acoustic Assessment Report" or "Noise Assessment Report"
means the report submitted in support of the Approval (and usually referenced in the Approval) that demonstrates through acoustic modelling the subject wind facility is in compliance with the applicable noise limits defined in the Noise Guidelines for Wind Farms, Reference [4].
"Acoustic Audits"
means E-Audits and/or I-Audits.
"Acoustic Audit – Emission (E-Audit)"

means an investigative procedure that is compliant with:

  1. the Standard CAN/CSA-C61400-11-07, Reference [1], or
  2. the CAN/CSA-IEC 61400-11:13, Reference [6], or
  3. at the Director’s discretion, compliant with another equivalent standard.

It consists of measurements in close proximity to wind turbines. The E-Audit is used to determine compliance with the manufacturer’s acoustic equipment specifications and emission data for wind turbines included in the Acoustic Assessment Report.

"Ambient sound level"
means background sound level.
"Approval"
means a Certificate of Approval issued under section 9 of the Environmental Protection Act (EPA), a Renewable Energy Approval (REA) issued under section 47.5 of the EPA, or an Environmental Compliance Approval (ECA) issued under Part II.1 of the EPA.
"A-weighting"
means the frequency weighting characteristic as specified in the International Electrotechnical Commission (IEC) Standard 61672, Reference [7], and intended to approximate the relative sensitivity of the normal human ear to different frequencies (pitches) of sound. It is denoted as "A".
"A-weighted sound pressure level"
means the sound Pressure Level modified by application of an A-weighting network. It is measured in decibels, A-weighted, and denoted "dBA".
"background sound level"
means the sound level that is present in the environment, produced by noise sources other than the source under impact assessment. The background sound level is typically caused by sounds from nature for Receptors removed from urban areas, or by road traffic for Receptors in urban/suburban areas. Highly intrusive short duration noise caused by a source such as an aircraft fly-over or a train pass-by (including light rail transit, subways and streetcars) is normally excluded from the determination of the background sound level.
"Binning"

with respect to Reference [1], I–Audits and RAM I-Audits, binning means the processing of measured sound level data by arranging the accumulated data in "bins" representing integer wind speeds, ±0.5 metres/second (m/s). Each "bin" is centered on the integer wind speed and spans 1 m/s. Open at the low end and closed at the high end. For example, the 7 m/s bin ranges from 6.50 m/s to 7.49 m/s (inclusive).

With respect to Reference [6], binning means the processing of measured sound level data by arranging the accumulated data in "bins" representing half-integer wind speeds, ±0.25 metres/second (m/s). Each "bin" is centered on the integer or half-integer wind speed and spans 0.5 m/s. Open at the low end and closed at the high end. For example, the 12 m/s bin ranges from 11.750 m/s to 12.249 m/s (inclusive).

Once binned, the mean (logarithmic average) of the Leq is computed for each wind speed bin.

"Class 1 Area"
means an area with an acoustical environment typical of a major population centre, where the background sound level is dominated by the activities of people, usually road traffic, often referred to as "urban hum".
"Class 2 Area"
means an area with an acoustical environment that has qualities representative of both Class 1 and Class 3 Areas:
  1. sound levels characteristic of Class 1 during daytime (07:00 to 19:00 or to 23:00 hours);
  2. low evening and night background sound level defined by natural environment and infrequent human activity starting as early as 19:00 hours (19:00 or 23:00 to 07:00 hours).
"Class 3 Area"
means a rural area with an acoustical environment that is dominated by natural sounds having little or no road traffic, such as the following:
  1. a small community with less than 1,000 population;
  2. agricultural area;
  3. a rural recreational area such as a cottage or a resort area; or
  4. a wilderness area.
"Complete E-Audit"

means an audit report for a wind turbine based on the measurement protocol defined in:

  1. Reference [1], and conducted at the standardized wind speeds of 6, 7, 8, 9 and 10 m/s (10 m height), or
  2. Reference [6] or
  3. at the Director’s discretion, compliant with another equivalent standard.

As noted in References [1] and [6], measurements of sound pressure levels and wind speeds are to be made simultaneously over short periods of time (i.e. six weeks or approximately one season).

"Complete I-Audit"
means an audit report for a wind facility that for each wind speed bin between four (4) and seven (7) m/s (inclusive), there is sufficient one (1) minute equivalent sound level data (Leq). Specifically, 120 data points for measurements when the turbines are operational and 60 data points for ambient measurements when the turbines are parked.
"dBA"
means the A-weighted sound pressure level.
"Decibel"
means a dimensionless measure of sound Level or sound Pressure Level, denoted as dB.
"Director"
means a person appointed by the Minister of the Environment and Climate Change pursuant to section 5 of the Environmental Protection Act (EPA) as a Director for the purposes of section 47.5 of the EPA.
"District Manager"
means the District Manager of the appropriate local district office of the Ministry where the wind facility is geographically located.
"equivalent sound level, Leq (T)"
means the A-weighted sound pressure level of a steady sound carrying the same total energy in the time period T as the observed fluctuating sound. The time period T is usually stated in hours. Leq without a specific time period means one hour Leq (1).
"exclusion limit"
means the lowest value of the sound level limit at a specific point of reception for the stationary source, i.e., the sound level limit when the background sound level is below this exclusion limit. For example, 40 dBA at 6 m/s (10m height).
"Ministry"
means the Ministry of the government of Ontario responsible for the EPA and includes all officials, employees or other persons acting on its behalf.
"Noise Abatement Action Plan" or "NAAP"
means the noise Abatement program developed by the owner/operator of the wind facility to achieve compliance with the sound level limits set out in section D6 of this document. The Abatement program must be reviewed and approved by the Ministry before it is incorporated into the wind facility.
"Noise"
means unwanted sound.
"Non-compliance"
is a state achieved when a person, who is bound by legal provision(s), does not act in accordance with the legal provision(s).
"Participating receptor"
has the same meaning as in the Noise Guidelines for Wind Farms and is subject to the same qualifications described in that document, Reference [4].
"Point of reception"
has the same meaning as in the Noise Guidelines for Wind Farms and is subject to the same qualifications described in that document, Reference [4], and must be listed in the Acoustic Assessment Report referenced in the Approval.
"Qualified acoustical practitioner" or "Practitioner"

means a person trained and currently active in the field of environmental acoustics and noise/vibration control who is familiar with Ministry procedures and has a combination of formal university education, training and experience necessary to perform the wind turbine noise measurements. It is recommended that the Qualified acoustical practitioner be a Professional Engineer.

Through the Professional Engineers Act, Professional Engineers Ontario (PEO) governs licenses and certificate holders and regulates professional engineering in Ontario. PEO defines professional engineering to be:

  1. any act of planning, designing, composing, evaluating, advising, reporting, directing or supervising (or the managing of any such act);
  2. that requires the application of engineering principles; and
  3. concerns the safeguarding of life, health, property, economic interests, the public welfare or the environment, or the managing of any such act.

In Ontario, only those individuals who have demonstrated that they possess the necessary qualifications and have been licensed by PEO can use the title Professional Engineer, which is often abbreviated as "P.Eng."

"RAM I–Audit"

means a Revised Assessment Methodology (RAM) for I-Audits conducted in accordance with section E5.5 of this document. Significant provisions of this methodology are as follows:

  1. requires downwind assessment between the closest turbines(s) and the assessment location;
  2. requires the closest turbine(s) to be operating at or within approximately 90% of its maximum sound power level;
  3. expands the measurement wind bins from four (4) (4 to 7 m/s) to seven (7) bins (1 to 7 m/s); and
  4. allows the assessment/analysis to be based on fewer measurements.
"receptor"
means a point of reception, or when applicable (refer to Appendix F3), a Participating receptor or an alternate measurement location used as part of an I–Audit.
"setback"
means the horizontal distance (plan-view) in metres separating the wind turbine coordinates and the coordinates of a receptor.
"sound level"
means the A-weighted sound pressure level.
"sound level limit"
means the limiting value described in terms of the one hour equivalent sound level, Leq. For example, 40 dBA at 6 m/s (10 m height).
"sound power level" or "Lw"
means the rating that, is given to a wind turbine by the manufacturer of the wind turbine, calculated in accordance with standard CAN/CSA-C61400-11, "Wind Turbine Generator Systems – Part 11: Acoustic Noise Measurement Techniques". In this document, the level may also refer to the value associated with a wind turbine at its origin, (fixed/stationary location).
"sound pressure"
means the instantaneous difference between the actual pressure and the average or barometric pressure at a given location. The unit of measurement is the micro Pascal (µPa).
"sound pressure level"

means twenty times the logarithm to the base 10 of the ratio of the effective pressure (µPa) of a sound to the reference pressure of 20 µPa.

It is a value associated with a distance from a stationary noise source (wind turbine or transformer substation). In this document, the value may also refer to the sound received from a wind turbine at a measurement location.

"tonality"
means a pronounced audible tonal quality of the sound such as a whine, screech, buzz or hum.
"urban hum"
means aggregate sound of many unidentifiable noise sources due to the activities of people and primarily composed of road traffic related sound sources.
"Wind Rose"
means a diagram showing the wind directions and wind speed class (range of wind speeds) encountered at a measurement location during a measurement interval of interest. Using apolar coordinate system of gridding, the frequency of winds over a time period is plotted by wind direction, with color bands showing wind speed ranges. The direction of the longest spoke shows the wind direction with the greatest frequency (prevailing wind direction). Wind roses typically use 16 cardinal directions, such as north (N), NNE, NE, etc.

A3 Purpose

The document is comprised of the following five parts:

  • Part A provides a general overview, including the definitions and references used in this document.
  • Part B provides guidance to Ministry staff when investigating complaints concerning noise due to the operation of a wind turbine or a wind facility. The intent is to provide Ministry staff with the technical tools to determine if the noise complaints require additional investigation in the form of acoustic screening measurements as detailed in Part C of this document.
  • Part C provides guidance to Ministry staff and/or Qualified acoustic practitioners to perform acoustic screening measurements to determine if a complaint warrants a detailed acoustic audit (I-Audit) as detailed in Part D of this document.
  • Part D provides guidance to Qualified acoustic practitioners that undertake detailed Acoustic Audits or complaint investigations of wind facilities (I-Audits). This part of the document will be used to confirm compliance with Ministry sound level limits in section D6 of this document.
  • Part E provides direction to Qualified acoustic practitioners when assessing the results of E-Audits and I-Audits against the applicable sound level limits. The guidance will allow Qualified acoustic practitioners to determine if the measured values are acceptable.

A4 Scope

The scope of the document aims to encompass the pertinent aspects of noise complaints, Approval audits and compliance assessments resulting from the operation of wind facilities. This involves a range of issues including turbine locations and distances, compliance with conditions of Approvals, screening of complaints and detailed measurements of the wind facilities sound levels.

The procedures included in this document  primarily relate to large modern commercial/industrial wind facilities with rated electrical power in the megawatt (MW) range (i.e. Class 4 wind turbines as classified under Ontario Regulation 359/09), and the focus is mainly on Receptors in Class 3 areas. However; some of the information may also be applicable to smaller wind turbines, namely Class 2 and 3 wind turbines (as classified under Ontario Regulation 359/09), and the installation of wind facilities in urban areas.

Sound from wind turbines that satisfy the applicable sound level limits may be audible and result in complaints. This document will address complaints of this nature. However, wind turbine noise in the infrasound range or ultrasound ranges (i.e. outside the normal audio range; less than 20 hertz or greater than 20,000 hertz), transformer substation noise, and other issues such as shadow flicker or health effects are beyond the scope of this document.

A4.1 Qualitative screening process (Part B of this document)

The initial screening is a qualitative assessment to focus on compliance issues related to conditions and parameters used in the Approval process.

Based on the results from the qualitative screening, a decision can be made whether to perform a quantitative screening (Part C of this document), or carry out detailed acoustic measurements (Part D of this document), at the site of the complainant. In some cases, based on any screening result in this protocol, the wind facility operator may decide to voluntarily undertake actions to reduce the noise impact.

A4.2 Quantitative screening process (Part C of this document)

The quantitative screening involves short-term attended acoustic measurements and/or acoustic recording at a receptor to determine if detailed acoustic measurement(s) is required to assess compliance with noise limits in Reference [4].

A4.3 Detailed acoustic measurements (Part D of this document)

The detailed acoustic measurement procedure is intended to determine the sound levels produced by the operation of a wind facility at a receptor/measurement location, at all applicable wind speeds, to assess compliance with the Ministry’s sound level limits.

A4.4 Compliance evaluation and transition rules (Part E of this document)

A4.4.1 Compliance evaluation

Part E of this document addresses how the Ministry will review E-Audits and I-Audits and what steps (options) an owner / operator of a wind facility can take to address audits that are incompletefootnote 1 or show exceedances. Part E applies to all wind facilities (existing, under construction, as well as future wind facilities).

Part E also outlines how the Ministry plans to verify and address compliance with the applicable sound level limits.

A4.4.2 Transition rules for I-Audits

This document replaces the previously applicable document, "Compliance Protocol for Wind Turbine Noise, Guideline for Acoustic Assessment and Measurement", January 2011. All Approvals, regardless of when they were issued, which include conditions requiring owners/operators of wind facilities to carry out two I-Audits in accordance with Part D of the Compliance Protocol, are now subject to Part D of this document.footnote 2

However, for I-Audits submitted to the Ministry before the date on this document, the revised data filtering requirements in Part D, such as, but not limited to, the downwind data and the 85% power output of the closest wind turbine, do not apply. Any I-Audits submitted to the Ministry after the date on this document will be subject to all of the requirements in Part D of this document.

In addition, Part D of this document contains the following two options for carrying out an I-Audit:

  1. a standard I–Audit
  2. a revised assessment methodology (RAM) I–Audit

If incomplete I–Audits are submitted to the Ministry, Part E of this document contains the following three options for owners / operators of wind facilities to choose from to remedy the incomplete I-Audits:

  1. supplement the I-Audits with existing data and reassess using this document
  2. combine the two I-Audit measurementsfootnote 3 and then conduct an additional I-Audit using this document
  3. conduct two new I-Audits using this document
A4.4.3 Acceptable standards for E-Audits

Irrespective of the date on this document, any E-Audit required by an Approval or complaint investigation can be conducted in accordance with either of the following publications:

  1. Reference [1], CAN/CSA-C61400-11-07, "Wind Turbine Generator Systems – Part 11: Acoustic Noise Measurement Techniques"
  2. Reference [6], CAN/CSA-IEC 61400-11:13, "Wind Turbines – Part 11: Acoustic Noise Measurement Techniques", Canadian Standards Association

A5 Background sound levels

Unlike most industrial or commercial noise sources, the sound immissions from wind turbines occur during wind conditions that typically induce significant levels of background noise due to the wind itself.

The background sound levels during conditions when the wind turbines are in operation near their rated generating capacity are comparable to the sound levels emitted by the wind turbines themselves. Consequently, determination of compliance is challenging and it is necessary to have an accurate account of the contribution from each source (wind and wind facility). An additional challenge is that conventional acoustic instrumentation, normally used for the measurement of industrial noise sources, is prone to produce erroneous signals due to the interaction of wind blowing over the microphone (including a windscreen), particularly at winds speeds at 4 m/s and higher.

Consequently, in order to accurately measure the sound levels due to wind turbines alone, a specialized technique is necessary (described in Part D of this document).

Part B: Complaint assessment – qualitative screening

B1 Purpose

The qualitative screening is the initial step in the assessment of a noise complaint regarding a wind turbine or wind facility. It does not require detailed calculations or sophisticated measurements and uses conservative assumptions regarding the noise impact of a wind facility.

The qualitative screening assists in evaluating the complaint with respect to specific parameters used in the Approval. Following this initial screening, and if required, further quantitative screening may be performed.

B2 Qualitative screening

The following steps are recommended to be performed in sequence but can also be performed in parallel.

B2.1 Step 1 – initial screening

Determine the current setback from the receptor to the closest wind turbine. A receptor located within 1,500 m of a wind turbine may be considered to be potentially in a noise area ranging from about 30 dBA and greater depending on the distance and number of turbines (within approximately 3 kilometers (km) of the receptor). Outside of this 1,500 m distance any detectable sound levels from land based wind turbines will not exceed the Ministry’s sound level limits.

Therefore, further noise assessment would not be practical or necessary and this should be communicated to the complainant. However, the owner/operator of the wind facility will be required to verify that all wind turbines (and if applicable, transformers) within the facility are operating:

  • within the manufacturer’s performance parameters (i.e. there are no maintenance issues)
  • in the correct mode (not a de-rated mode)
  • with the correct firmware (correct pitch of blades and torque of turbine)

Alternatively, if the closest wind turbine is within 1,500 m of the subject receptor then proceed to Step 2 (section B 2.2).

B2.2 Step 2 – site visit and interview

If the closest wind turbine is within 1,500 m, then obtain a full description of the nature of the complaint including specific details about the noise from the complainant. The purpose of obtaining the description is to identify from the complainant specific details about the noise issue that would assist in determining further action. A set of open-ended questions are included in the sample form in Part F (section F1) of this document.

The purpose of the site visit and interview is to identify noise sources and features that will have an impact on the background noise and possibly on acoustic measurements. Take note from site observations of any other noise sources within the complainant’s property and in the immediate vicinity (i.e. dryers, coolers, fans, generators, etc.). Also, take note of any unusual features such as trees, shrubbery, water features, hills, ancillary buildings, etc.

Examine the wind facility to ensure that the constructed facility is consistent with the Approval. For example, observe whether the blades of the wind turbines were modified during the project installation by the addition of vortex generators, dyno-tails, etc., such that the aerodynamics of the blades are no longer consistent with the Approval.

Determine the actual setback distance between the subject receptor and the closest wind turbine(s) and proceed to Step 3 (section B 2.3)

B2.3 Step 3 – check for setback reductions

Verify the locations of all wind turbines up to 1,500 m surrounding the property of the complaint site in order to determine if there has been a change in the layout of the wind facility relative to the layout that was approved.

Any significant discrepancies with respect to the Approval will require the owner/operator of the subject wind facility to apply for an amendment to the Approval, and may result in Abatement or enforcement action if warranted.

If it is found that the discrepancy in some wind turbine locations (within the 1,500 m radius) resulted in Setbacks from the complaint receptor reduced by more than 4% (tolerance value) from the approved layout, then the discrepancy will be considered as a major project design change. If the Approval specifies a lower tolerance value, (i.e. 2% or 10 m), this value is applicable in the distance setback reduction assessment.

Technically, a reduction in setback due to the closest wind turbine of 4% can result in an increase in sound level at the receptor of 0.35 dB. Although such an increase is not perceptible, it may result in an excess over the sound level limit at that location.

In this case, the assessment needs to be verified using the as-built layout affecting the complainant’s location and using the prediction model specified in the Approval. Specifically, the parameters to be used must reflect the worst-case noise impact by assuming the maximum acoustic immissions from the turbines against the lowest applicable sound level limit.

If the modelling calculations determine a level greater than the sound level limit, the owner/operator of the wind facility may be required to implement appropriate noise Abatement measures to achieve compliance with the sound level limits or follow the guidance in Part E of this document. However; further assessment may not be required if the owner/operator of the wind turbine is prepared to voluntarily reduce the sound levels.

If the reductions of setback distances are not greater than 4% then proceed to Step 4 (section B2.4). If the Approval specifies a lower tolerance value, (i.e. 2% or 10 m), this value is applicable in the distance setback reduction assessment.

Refer to Part F (section F2) of this document for a summary of the procedure and a partial sample assessment.

B2.4 Step 4 – check predicted noise impact

Check the calculated sound level corresponding to the receptor included in the Acoustic Assessment Report for the wind facility. If the results indicate compliance within a margin of at least 5 dB below the limit (i.e. 35 dBA or lower), further assessment at this site would be at the discretion of Ministry staff.

However; if the predicted level is less than 5 dB from the limit (i.e. above 35 dBA), then further assessment at the complaint location would be warranted. Proceed to Part C of this document or, alternatively, in the case of a significant oversight and in agreement with the owner/operator of the wind facility, Part D of this document.

Part C: Complaint assessment – quantitative screening

C1 Purpose

The quantitative screening process was designed to provide additional information to that obtained in the initial qualitative screening process. The quantitative screening involves use of instrumentation to obtain sound measurements.

The purpose of the quantitative screening process is to determine the need for further action in evaluating the complaint resulting from wind turbine or wind facility noise. Detailed long-term acoustic measurements at the site of the complainant may be appropriate as a result of the quantitative screening. This process is also applicable to owners/operators of wind facilities that are required to submit an E and/or I-Audit as a condition of Approval or by any other instrument under Ministry legislation. Valid complaints may be investigated, even if the subject facilities have demonstrated, or are required to demonstrate, compliance via an E and/or I-Audit.

In the case of several significantfootnote 4 excesses above the Approval sound level limits, there may not be a need or justification for a detailed acoustic audit to be completed for Ministry district staff to determine, in agreement with the owner/operator of the facility, that non-compliance is occurring.

The excess must only represent the wind facility’s sound levels, not the total noise, (i.e. the background sound level must be logarithmically subtracted from the measurements).

C2 Attended screening measurements

The measurement of sound levels at Points of Reception located at significant distances from the turbines require special instrumentation, specific testing conditions, and careful analysis of the data.

The objective is to determine the wind turbine’s or wind facility’s noise impact at a point of reception expressed as an equivalent sound level. It is recommended that the attended screening measurements be carried out at times when the background sound level is very low. To the extent possible, the measurements should be performed at times when wind turbines operate near their maximum output (maximum rotational speed) while wind speeds at ground elevation (height of 4.5 m or less) are low, optimally not exceeding 3 m/s with a 4 m/s maximum.

C2.1 sound level measuring instrumentation

The sound level measuring instrumentation consists of the following:

  • Integrating sound level meter
  • Acoustic calibrator
  • Wind screen and cables

The sound level measuring instrumentation must meet the following requirements:

  • sound level meter specifications according to the IEC 61672-1 (2002), "Electroacoustics – sound level Meters, Part 1": Specifications, Reference [7].
  • Class 1 or Class 2 microphone systems. Should a Class 2 rather than a Class 1 microphone system be used, it is recommended that the noise floor of the microphone is at least 25 dBA.
  • The instrumentation should have a constant frequency response between 20 Hz to 20,000 Hz.

C2.2 Acoustic calibrator

The complete sound measurement system, including any recording, data logging or computing systems, shall be calibrated immediately before and after the measurement session at one or more frequencies using an acoustic calibrator on the microphone.

The acoustic calibrator shall have an accuracy equal to or better than ±0.3 dB and fulfill the requirements of Class 1 according to IEC 60942:2003, Reference [8], in the temperature range where it is used.

C2.3 Anemometer

The anemometer shall have accuracy equal to or better than ±0.5 m/s and an output resolution of 0.2 m/s or less.

C2.4 Measurement procedure

C2.4.1 receptor location

Measurements for the purposes of complaint assessment should be performed at a point of reception. It should be noted that a measurement location at a two-storey building will be closer to the wind turbine than the modeled location which is at the centre of dwelling.

C2.4.2 Time of measurements

The noise measurements associated with the complaint assessment should be mindful of the complaint character. In addition, the measurements should consider predictable worst case parameters such as high wind shear and the downwind conditions from the closest wind turbine to the measurement location. It is recommended that the measurements be performed during lowest background noise conditions. This period of time is normally in the late evening or nighttime.

C2.4.3 Microphone height

The measurement position at a given receptor is outside the identified receptor dwelling. Preferably, the measurement height should be consistent with the receptor height modelled for Approval purposes.

C2.4.4 Microphone position

Appropriate judgment is expected to be used when positioning the microphone. Some general guidance is given below:

  • The microphone position shall be sufficiently away from any large reflecting surfaces (minimum of 5 m recommended). This requirement does not apply if using a small vertical reflecting board attached to the building façade.
  • The microphone should be located at a point near the receptor dwelling that is not shielded from the closest wind turbine noise (or wind facility). Wherever possible, the microphone should not be located near deciduous trees or foliage that may affect the noise.
C2.4.5 Anemometer location

The anemometer location (to measure wind speed) should be in the vicinity of the noise measurement location (within 15 m). Wherever possible, the measurement position should represent an area where the wind is not shielded by nearby buildings or objects.

The wind speed measurement should also be performed at the microphone height to comply with the maximum wind speed requirement specified in section C2.4.6.

Wind speed measurements should be carried out at the same time as the noise measurements.

C2.4.6 Acoustic measurements

The objective of the acoustic measurements is to determine the overall equivalent sound level Leq when the turbines are operational under the following conditions:

  • The optimum range of wind speeds at the microphone location is up to 3 m/s
  • The maximum wind speed at the microphone location does not exceed 4 m/s
C2.4.7 Extraneous noise sources

Measurements are to be inhibited when the sound level is affected by noise from extraneous sources such as vehicle noise, dogs barking and wind gusts (i.e. other than wind turbine sound).

The same result can also be achieved by digitally recording the sound level time history and later editing out the extraneous events and recalculating the descriptors such as Leq. This should address measurement situations where extraneous sounds were not inhibited.

C2.4.8 Duration of measurement

Noise measurements must be performed over a minimum period of one hour. The actual accumulated time of the measured Leq needs to be at least 20 minutes. This should represent the worst case equivalent sound level Leq during the one hour period, following the inhibition of the measurements due to extraneous sources.

C2.4.9 Tonality (tonal assessment)

If a tone is clearly audible and continuous, a 5 dB tonal adjustment should be applied to the measured sound level.

C2.4.10 background sound level

This procedure will require the background sound level to be logarithmically subtracted from the overall equivalent sound level Leq and therefore, will require a separate measurement of the background sound level. Note that the background sound level does not include the contribution from the wind turbine noise.

Where appropriate, the background sound level should be measured using the same instrumentation and for the same duration as the overall sound level described in this section.

C2.5 Documentation

The following information should be reported:

  1. Conditions during the measurement, including but not limited to:
    • time and dates of the measurement
    • temperature and humidity
    • general weather conditions
    • range of wind speeds encountered
    • wind direction
    • confirmation that the wind turbines were operating (i.e. rotational speed of the closest wind turbine)
  2. Statement noting whether or not Tonality was observed (qualitative assessment)
  3. Results of measurements in terms of the equivalent sound level Leq.
  4. Diagram and pictures showing the location of instrumentation, location of buildings and other local features, and the location of wind turbines.

C2.6 Compliance with limits

The Leq results of the attended measurements obtained during this screening process should be compared with the applicable limits contained in Reference [4] and given in the table below:

Standardized Wind Speed at 10 m Height, m/ssound Level Limit dBA
< 440.0
540.0
640.0
743.0
845.0
949.0
1051.0

C3 Acoustic recording by resident/complainant

As mentioned earlier in section C1, the following procedure is a screening tool used to determine if a detailed acoustic audit as per Part D of this document is required. This procedure should indicate the potential for compliance or non-compliance at times when the resident/complainant finds the operation of a wind facility to be objectionable and when Ministry staff cannot attend the site.

If a Part C3 measurement is completed and the MOECC requires the owner / operator to complete a detailed acoustic audit outlined in Part D, upon request the MOECC may share the Part C3 report with the owner/operator.

C3.1 Scope

The method of measurement described in this section provides information on instrumentation requirement, measurement procedure, data analysis and documentation related to the measurement and recording of the wind turbine or wind facility noise initiated by the resident of the home where the complaint originated. The resident will only trigger the measurement cycle (10 minutes of measurements). The resident will not be involved in any aspect of the equipment setup, calibration or data retrieval and analysis.

The measurement and analysis procedure applies to sound in the audible frequency range, (20 Hz to 20,000 Hz), and includes the measurement of the equivalent sound level, Leq, at a receptor.

C3.2 Overview

A resident via a sound level meter (and/or an audio recording device) securely locked in a tamper proof case with an external trigger, initiates this acoustic screening measurement. Ministry staff or a Qualified Practitioner will set up and calibrate the instrumentation. The approach may be utilized when it is not possible for Ministry staff to make attended observations or measurements at a resident’s home during periods when a resident deems wind turbine or wind facility noise disturbing.

The procedure involves installing a sound recording system/device at a resident’s home to collect a minimum of twelve (12) high quality, 10 minute sound recordings of the offending noise at the exact time of the occurrence (refer to section C3.4.8 for more details regarding recording intervals).

The recording equipment must have the capability of being activated by a resident at any time from inside the resident’s home. It must automatically perform a recording of set duration (10 minutes), and store the audio recording along with the date and time of the recording. The recordings will be analyzed off site.

The off-site analysis will also require operational information of the wind facility such as turbine power output, wind speed, rotation speed of rotor/blades and wind direction at the time of the analysis. In addition, it will require details of atmospheric conditions at the resident’s home.

If the analysis, which includes background sound levels subtracted from the measured sound levels or portions of the measured sound levels that only include the wind facility, indicates that wind turbine noise is audible and that the majority of the 10 minute Leq s indicates that the wind facility sound levels exceed the applicable limits, additional assessment would be warranted. This additional work may consist of one or combination of the following:

  • Additional C 3 acoustic recordings at the resident’s location;
  • Attended screening measurements in accordance with section C2; or
  • Detailed acoustic measurements in accordance with Part D of this document.

C3.3 Instrumentation

C3.3.1 Acoustic instrumentation

The instrumentation is intended for short-term noise measurements, typically seven to eight uninterrupted consecutive days. The recording device can be comprised of either a digital recorder or a sound level meter capable of recording sound files and Leq s simultaneously. The minimum requirements of both devices and the peripheral equipment are noted below:

Minimum requirements of the digital recorder and sound level meter
  1. Class 1 or Class 2 microphone systems.footnote 5
  2. Ability to be triggered by a resident inside the residence.
  3. The instrumentation must have a constant frequency response over 20 Hz to 20,000 Hz.
  4. The filters meeting the requirements of IEC 61260 for Class 1 filters.
  5. Ability to record a 10 minute digital audio waveform file ("wav file"footnote 6 or equivalent non compressed digital formats at a sampling rate of at least 8,000 Hz. Depending on the composition of the background sound levels, larger sampling rates (i.e. 44,000 Hz) may be required. The minimum sampling resolution should be at least 16 bit. The Ministry at its discretion may require the submission of the original and/or edited recordings.
  6. In addition to the requirements above, appropriate software is also required to:
    • determine the 10 minute Leq from the 10 minute sample
    • analyze the files in 1/3rd octaves
C3.3.2 Narrowband spectra determination (both devices)

This equipment shall fulfill the relevant requirements for IEC 61672-1(2002), Reference [7], over the frequency range of 20 Hz to 20,000 Hz.

C3.3.3 Acoustic calibrator

The complete sound measurement system, including any recording, data logging or computing systems, shall be calibrated immediately before and after the measurement session at one or more frequencies using an acoustic calibrator on the microphone.

The acoustic calibrator shall have an accuracy equal to or better than ±0.3dB and fulfill the requirements of Class 1 according to IEC 60942:2003, Reference [8], and shall be used within its specified environmental conditions.

C3.3.4 Wind screens

For the measurement of wind turbine sound immission, a primary windscreen must be used. It is recommended that the primary windscreen consist of open cell foam with a diameter of approximately 90 mm centered on the diaphragm of the microphone. It is further recommended that a larger diameter secondary wind screen (approximately 450 mm) be used to reduce the noise from wind blowing over the microphone.

The specifications of the secondary wind screen are indicated in CAN/CSA-C61400-11-07, Reference [1] and CAN/CSA-IEC 61400-11:13 Reference [6] as follows:

…could, consist of a wire frame of approximate spherical shape, at least 450 mm in diameter, covered with a 13 mm to 25 mm layer of open cell foam with a porosity of 4 to 8 pores per 10 mm. This secondary spherical windscreen shall be placed symmetrically over the smaller primary windscreen.
C3.3.5 Anemometer

The anemometer and its signal processing equipment shall have a maximum deviation from the calibration value of ±0.5 m/s in the wind speed range from 0 m/s to 12 m/s. The anemometer itself shall have an accuracy equal to or better than ±0.3 m/s at 10 m/s and an output resolution of 0.2 m/s or less. Wind direction should be measured within 3 degrees. The data should be averaged over at least a 10-minute period.

C3.3.6 Calibration

The sound level meter and calibrator must have a valid calibration certificate traceable to a qualified laboratory. The maximum time from the last calibration shall be as stated by the manufacturer. If a maximum time is not stated, a time period of one year shall be assumed.

C3.3.7 Tamper proof case

The device shall be secured within a tamper proof case, preferably within the resident’s dwelling. With the exception of the device’s external triggering component, the resident should not have access to the controls of the recording device. It is noted that the microphone extension cable, microphone and external power supply may all protrude out of the tamper proof case.

C3.3.8 External trigger

The device should be capable of starting a 10 minute digital recording when activated via an external trigger.

C3.4 Measurement procedure

C3.4.1 Time of measurements

Measurements are to be taken at the discretion of the resident.

C3.4.2 Microphone height

The measurement position at a given receptor is outside the identified receptor dwelling and at a height of 1.5 m for single storey dwellings or 4.5 m for two-storey dwellings. Preferably, the measurement height should be consistent with the receptor height modelled for Approval purposes.

C3.4.3 Microphone position

Appropriate judgement is expected when positioning the microphone. Some general guidance is given below:

  • The microphone position shall be sufficiently away from any large reflecting surfaces (minimum of 5 m is recommended).
  • The microphone should be located at a point near the receptor dwelling that is not shielded from the closest wind turbine noise (or wind facility). Wherever possible, the microphone should not be located near deciduous trees or foliage, which may dominate the noise environment.
C3.4.4 Anemometer location

The anemometer location should be in the vicinity of the noise measurement location (within 15 m), at a height of 10 m above ground. Provided it is practical the anemometer location should represent an area where the wind is not shielded by nearby buildings or objects.

C3.4.5 Anemometer measurements

Wind speed and direction measurements are carried out simultaneously and synchronously with the noise measurements. For each ten (10) minute interval, the average wind speed, and wind direction should be recorded. The minimum sampling rate should be 1 second or less.

C3.4.6 Acoustic measurements

sound and acoustic recordings are initiated with the device’s external triggering component at the discretion of the resident. The audio sample (not compressed), is recommended to be recorded with a sampling rate between 8,000 Hz and 44,000 Hz depending on the composition of the background sound levels. The minimum sampling resolution should be at least 16 bit.

C3.4.7 Supplementary measurements

For the time frame of assessment (days/nights when recordings were activated by a resident), the wind facility operator must provide a detailed summary of the wind facility’s operation. This information will include as a minimum:

  1. Identification of the closest wind turbine to the resident.
  2. Output power generation and rotational speed of rotor/blades, of relevant turbines (turbines with predicted sound immissions greater than 30 dBA at the resident’s home).
  3. Wind speed and direction data at hub heights of all wind turbines within 1,500 m of the receptor, that are part of the wind facility (or facilities) under investigation.

The analysis of these recordings will consist of aural listening for identification of wind turbine noise relative to other background sources. Results will be used to identify segments of audible wind turbine sounds useful for possible data analysis of sound level (A-weighted Leq and L90 of segments or frequency analysis for Tonality).

C3.4.8 Number of measurement intervals

The resident will be requested to record at least:

  1. nine (9) 10-minute audio recordings of instances when sound from the wind facility is considered disturbing, and
  2. three (3) 10-minute audio recordings of instances when sound from the wind facility is not considered disturbing (Ambient measurements).
C3.4.9 Tonality (tonal assessment)

Should a tone be clearly audible and continuous, a 1/3rd octave band frequency analysis of the turbine noise can be performed. The Tonality assessment should be conducted in accordance with the procedure in Reference [1] or at the Director’s discretion compliant with another equivalent standard. The Tonality adjustment should be made in accordance with the procedure described in ISO 1996-2, Reference [2].

C3.5 Assessment of measurements

C3.5.1 Turbines not audible

If the wind turbine(s) or wind facility is not audible in any of the recordings, then additional analysis is not required. The recordings have indicated that the wind facility’s noise is in compliance with the limits noted in the Approval.

C3.5.2 Turbines audible

If the wind turbine(s) or wind facility is audible in a recording that does not include extraneous noise sources, then the following additional analysis is required for the subject recording:

  1. Determine the value of the 10 minute Leq via software or obtain it directly from the recording device. If applicable and if there is a concern, the transmission loss of the secondary wind screen in octave bands, should also be accounted for in the calculation of the 10 minute Leq.
  2. If there is a concern, determine if the wind turbine noise is tonal.
  3. Obtain the average wind speed at the microphone height (1.5 or 4.5 m) over the 10-minute recording session.

Results of the 10 minute Leq, (including tonal penalty if applicable), are to be compared against the applicable sound level limits contained in the Approval and shown in the following table:

Standardized Wind Speed at 10 m Height, m/ssound Level Limit dBA
≤ 440.0
540.0
640.0
743.0
845.0
949.0
1051.0

It is acknowledged that if the measured values (background sound levels + turbines / wind facility) exceed the Approval’s limits, it does not necessarily imply the turbines are not in compliance; even if the turbines are audible. The excess could be due to the background sound levels.

In addition, if the background sound levels are greater than the applicable exclusion limits then the applicable limits are the background sound levels without extraneous noise sources (i.e. farm equipment).

C3.5.3 Background sound level

This procedure will require the background sound level to be logarithmically subtracted from the overall equivalent sound level Leq. Note that the background sound level does not include the contribution from the wind turbine noise.

C3.6 Documentation

The following information should be reported:

  1. Conditions during the measurement, including but not limited to:
    • time and dates of the measurement
    • temperature and humidity range
    • general weather conditions
    • range of wind speeds encountered
    • range of wind directions
    • confirmation that the wind turbines were operating
  2. Statement concerning whether Tonality was observed during the acoustic recordings. If Tonality was observed, provide details on how it was assessed in accordance with section C3.4.9
  3. Results of measurements in terms of the equivalent sound level Leq.
  4. If applicable (i.e. turbines are audible in recordings), comparison of the wind facility’s Leq values are to be made against the applicable sound level limits in the Approval. A statement of whether the wind facility complies with those limits will also be required.
  5. Diagram/drawing and pictures showing the location of instrumentation, location of buildings and other local features, and location of wind turbines.

A sample summary of a resident triggered measurements is included in Part F, section F4 of this document.

Part D: Complaint assessment – detailed acoustic measurements

D1 General

Detailed acoustic immission measurements (I-Audits) are normally carried out subsequent to a qualitative and/or quantitative screening (Parts B and C of this document) that suggests that the wind turbine(s) may be out of compliance with Ministry sound level limits. A detailed acoustic measurement may also be a requirement of an Approval.

D1.1 Purpose

This section establishes a detailed measurement procedure for long term acoustic measurements of wind turbine or wind facility noise. The objective of the detailed measurements is to determine the sound level produced by the operation of wind turbines or wind facility, at all applicable wind speeds, for comparison with Ministry sound level limits.

This measurement procedure also applies to acoustic audit measurements that may be required as a condition of an Approval or any other instrument under Ministry legislation. The Ministry may also require, at its own discretion, that specific measurements or assessment additional to those described herein be carried out.

However, the data filtering requirements, such as, but not limited to, the downwind data and 85% power output described in Section D 5.2 (Data Reduction and Filtering) of this document, do not apply to I-Audits that were:

  1. submitted to the Ministry prior to the date on this document, and
  2. prepared in accordance with the previously applicable document, "Compliance Protocol for Wind Turbine Noise, Guideline for Acoustic Assessment and Measurement," January 2011.

In addition, the measurements and analysis in this section should only be carried out by a Qualified acoustical practitioner or someone under the supervision of a Qualified acoustical practitioner.

D1.2 Scope

The method of measurement described in this section provides information on instrumentation requirement, measurement procedure, data analysis and documentation.

The method applies to a single turbine, or a group of turbines. It has been developed primarily for large modern commercial/industrial wind turbines with rated electrical power in the megawatt (MW) range; however, it may also be applicable to smaller turbines. It should be noted that typical sound power levels of large modern commercial/industrial wind turbines are in the range of 100 – 107 dBA.

The measurement and analysis procedure applies to sound in the audible frequency range (20 Hz to 20,000 Hz) and is based on the measurement of the A-weighted equivalent sound level, Leq, at a receptor. The application of this procedure is recommended for Receptors located at a distance up to approximately 1,500 m from the nearest turbine. This distance recommendation is only approximate; for example, it may be further limited by the local Ambient sound levels.

D1.3 Overview

The principle of the procedure is to measure the overall equivalent sound level (Leq, dBA) at a point of reception at times when the relevant turbines are operational and when they are not operational (i.e. parked). In both cases, the measurements are made by logging the equivalent sound level Leq in one-minute intervals along with 1/3rd octave band spectra within the 20 Hz to 20,000 Hz frequency range. Additionally, audio recordings of each interval are recorded for the purposes of post measurement listening and source verification. It is recommended that a minimum of 120 one-minute intervals when the turbines are operational be measured for each integer wind speed.

The ambient noise measurements are carried out with turbines in the vicinity of the point of reception parked. The parked turbines are those that, if operating, would contribute to or would likely contribute to the ambient equivalent sound level. In general, every effort should be made to park all of the turbines that would cause the cumulative predicted contribution at the receptor to rise above 30 dBA. It is recommended that a minimum of 60 one-minute intervals be measured for each integer wind speed when the turbines are parked.

If the wind direction at the measurement location has the potential to influence (30 dBA or greater) the ambient measurements (for instance a nearby roadway), then if appropriate, the measurements should be filtered accordingly. Please refer to Appendix F10 for more details.

Following the determination of the overall Leq and the ambient Leq at all applicable wind speeds and conditions, the ambient Leq is logarithmically subtracted from the overall Leq to determine the Leq produced by the wind facility.

Wind speed and direction measurements are carried out simultaneously and synchronously with the sound measurements for each one-minute interval.

In the event that the required data is not acquired within six (6) weeks of measurements, then on a case-by-case basis, the Ministry may permit appropriate (statistical) analysis on the data acquired, where necessary to derive valid conclusions, in accordance with good scientific data analysis techniques. In this case, all one-minute data (valid and excluded) should be submitted with the assessment.

D2 Instrumentation

D2.1 Acoustic instrumentation

The instrumentation is intended for long term, outdoor, unattended noise measurements.

D2.1.1 Sound level measurement

The sound level measuring instrumentation needs to meet the following requirements:

Additional filters can be considered, such as removal of individual events where the signal-to-noise ratio is low. This additional filtering should be discussed with Ministry staff to ensure that the data would be accepted.

D5.3 Effects of insects and fauna

The analysis shall identify the influence of any insects, fauna, or other extraneous but constant sources of noise and verify them through sound recordings. Noise from insects can be removed from the 1/3rd octave spectra of each measurement. It has to be shown, however, that the contribution of the wind turbine noise in those frequencies is minimal.

D5.4 Determination of turbine sound level

The measured sound levels when the wind facility is operating represent the overall sound levels, including the ambient noise. In order to determine the sound level produced by the wind facility, the Ambient sound level needs to be subtracted, on an energy basis (logarithmically), from the overall level.

Following the filtering and data reduction described above, the resulting equivalent sound levels (Leq) for all the remaining intervals should be plotted separately for both cases: turbines operating and turbines parked. The Leq levels should be plotted against the measured 10 m wind speed for those intervals.

D5.5 Data analysis

It is recommended that the "Binning method" be used for the analysis of the accumulated one-minute sound level data.

The accumulated sound levels, at one-minute interval levels, need to be binned by integer wind speed. Binning means arranging the sound level data within a “bin” representing an integer wind speed, ±0.5 m/s. Once binned, the mean (logarithmic average) and standard deviation of the Leq is computed for each wind speed bin. This is carried out for both the turbines operating and the turbines parked cases. Subsequently, for each integer wind speed the turbine noise contribution is computed by subtracting on an energy basis (logarithmically) the mean Leq of the turbines parked case from that of the turbines operating case.

The standard deviation of each wind speed bin must be reported. This added information may provide insight into the variation of the wind facility’s contribution and aid in understanding the wind turbine immission levels at the measurement point.

D5.6 Tonal assessment

The tonal audibility shall be determined for all valid data records. If a tone is identified at any of the wind speeds, the average tonal audibility correction shall be added to the final noise contribution of the wind turbine at those wind speeds.

At the discretion of the Ministry, an updated acoustic report may be required to account for this adjustment.

D6 Assessment of compliance

Results of measurements and analysis are to be compared against the applicable sound level limits contained in Reference [4] and shown in the following table:

Wind speed (m/s) at 10 m height (agl)45678910
Wind turbine sound level limits Class 3 area, dBA40.040.040.043.045.049.051.0
Wind turbine sound level limits Class 1 and 2 areas, dBA45.045.045.045.045.049.051.0

Results shall be rounded to the nearest integer for comparison with the limit for each wind speed category.

In order to be deemed in compliance the numerical values of the results must not exceed the limit at each wind speed category.

However, if the background sound levels are greater than the applicable exclusion limits then the applicable limits are now the background sound levels without extraneous noise sources.

D7 Documentation

The following conditions during the measurement should be reported:

Part E: E and I-Audits – Compliance evaluation

E1 Purpose

The purpose of this section is to describe the Ministry’s risk-based approach to its review of Acoustic Audits (E and I-Audits) for wind turbines, including how the Ministry plans to assess them for compliance purposes.

E-Audits verify the validity of the sound power levels provided by manufacturers, and used in acoustic models to determine the noise impact of a wind facility at receptor locations.

I-Audits verify the validity of predicted sound pressure levels in Acoustic Assessment Reports, and verify compliance with applicable sound level limits at receptor locations.

The Ministry has relatively broad authority under the Environmental Protection Act (EPA) to take steps to address non-compliance. All noise-related issues will be considered in accordance with the Ministry’s compliance strategy so that wind facilities operate in compliance with Approvals. This includes options of voluntary Abatement or mandatory Abatement in accordance with the "Compliance Policy Applying Abatement and Enforcement Tools", Reference [5].

Abatement options (either voluntary or mandatory) may vary from site to site and may include continued noise monitoring, implementation of a Noise Abatement Action Plan (NAAP) or the shutting down of turbines. In appropriate cases, the matter may be referred to the Ministry’s Investigations and Enforcement Branch.

More specifically, this section is intended to outline how the Ministry plans to review and evaluate the potential for increased noise impacts at Receptors in cases where there are noted technical violations. This may occur where E-Audit results show that the measured sound power levels of wind turbines exceed the sound power levels identified in the Approval. In most cases, exceedances in sound power levels are insignificant and unlikely to result in potential adverse effects at receptor locations.

Where measured sound power levels are higher than what was set out in the Approval, the Ministry’s main objective will be to determine whether the wind facility continues to meet the Ministry’s sound level limits at the receptor locations. The Ministry may do this by requesting the owner/operator of the wind facility to voluntarily undertake the further assessment outlined in this document, and/or by using compliance methods available under the EPA to require this additional work to be undertaken.

If the owner/operator of the wind facility can demonstrate, through the additional assessment outlined in this document, that the applicable Ministry sound level limits continue to be met at the receptor locations, the Ministry does not anticipate taking further compliance action. However, if sound level limits are not being met at the receptor locations, the Ministry will take appropriate action to require the owner/operator of the wind facility to achieve compliance.

This section also addresses situations where the Ministry receives incomplete E-Audits and/or I-Audits and describes the additional steps, or additional information, that may be required by the Ministry from owners/operators of wind facilities to address such situations.

It should be noted that while this section provides a general overview of the Ministry’s expected approach to its review of Acoustic Audits including how it will respond to compliance issues, there may be situations that will be handled differently or that will require deviations from this section. The proposed approach set out in this section, although anticipated to apply in the majority of cases, may not be appropriate in all circumstances.

E2 Review processes for wind turbine acoustic audits

Throughout the review processes, the Director and staff of the Ministry’s district office where the facility is located will work together to ensure that wind facilities operate in accordance with the Ministry’s requirements.

On a case-by-case basis, the Ministry may impose restrictions on a wind facility’s operations if, for example:

E3 E-Audit review processes

E3.1 Complete Submission

The Ministry will review the E-Audit, and if the measured sound power levels are below the sound power levels in the Approval plus 0.5 dB, the Ministry will inform the owner/operator of the wind facility that no further action is required. The Ministry considers an increase of up to 0.5 dB from an approved sound power level to be acoustically insignificant and unlikely to result in any perceptible difference in sound levels at the Receptors.

However, if the E-Audit notes that the measured sound power levels exceed the sound power levels stated in the Approval by more than 0.5 dB, the owner/operator can follow one of the two options set out below (see Figure 1 in section E4 of this document).

Please refer to section F, Appendices F5 and F6, for items which must be submitted with the acoustic audit.

E3.1.1 Option 1: Re-modelling

The owner/operator may choose to remodel the wind facility based on the sound power levels in the E-Auditfootnote 9 and the modelling parameters in the Acoustic Assessment Report used to support the Approval.

The owner/operator will then be required to submit an updated Acoustic Assessment Report to the Ministry (see Figure 2 in section E4 of this document). For further direction, proceed to section E3.1.3 of this document.

E3.1.2 Option 2: I-Audit or RAM I-Audit

Alternatively, the owner/operator may choose to conduct an I-Audit at the point of reception with the greatest predicted noise impact from the wind turbine type/model under investigation (worst case receptor). If an I-Audit at the worst case point of reception was already conducted as part of a condition of an Approval, that I-Audit can be used to satisfy this requirement. If the conducted I-Audit is incomplete, the owner/operator will be required to follow one of the options outlined in section E5.2 of this document, which could include a RAM I-Audit.

See Figure 1 in section E4 of this document for a summary of the procedure.

E3.1.3 Sound levels that are acceptable to the Ministry

If, after following one of the two options, the owner/operator of the wind facility is able to show that the remodeled / measured sound levels meet the Ministry’s sound level limits at the Point(s) of reception/measurement location(s), the Ministry will confirm that:

E3.1.4 Sound levels that do not meet the Ministry’s sound level limits

If, after following one of the two options, the owner/operator of the wind facility cannot demonstrate that the remodeled/measured sound levels meets the Ministry’s sound level limits at the Point(s) of reception/measurement location(s), the owner/operator will be required to submit a NAAP to the Director and the District Manager. The owner/operator of the wind facility will usually be required to submit the NAAP within 60 days of submitting the results of one of the two options, or within a date agreed to by the Director and/or District Manager. The Ministry will review and approve the NAAP.

The Ministry will typically require that the NAAP outline proposed timelines and mitigation measures to:

Within 90 days after the implementation of the NAAP, the owner/operator of the wind facility will be required to complete and submit an E-Audit to the Ministry to verify compliance.

The Ministry will also require that all E-Audit reportsfootnote 11 be posted on the project website, within 10 business days of the E-Audit being submitted to the Director and District Manager. The Ministry expects the owner/operator to ensure that the E-Audit reports, and any updates, remain available to the public on the project website for the life of the project.

E3.1.5 Notes on compliance

For purposes of section E3.1 of this document, the Ministry will generally not take further compliance action if either of the following conditions are satisfied:

For example, if a turbine is approved at a sound power level of 103.2 dB, then an acceptable sound power level will be at or below 103.2 + 0.5 = 103.7 dB.

E3.2 Incomplete E-Audit submission

E3.2.1 Deviations from the standard

In general, it is not acceptable to deviate from Standard CAN/CSA-C61400-11 or another procedure approved by the Ministry unless the E-Audit report demonstrates that the procedure used in the assessment results in the measurement and/or calculation of conservative sound levels.

The Ministry expects E-Audit reports to include justifications for any deviations from the applicable standard or another procedure approved by the Director. If a method is not demonstrated to be more accurate/conservative than the approved methodology, the audit report will not be deemed acceptable.

Examples of deviations that the Ministry would not consider acceptable include the following:

Examples of deviations that the Ministry would consider acceptable include the following:

The Ministry will require additional supporting information from the owner/operator of the wind facility for any deviations from Standard CAN/CSA-C61400-11:07, Reference [1] or Standard CAN/CSA-IEC 61400-11:13, Reference [6], or another procedure approved by the Director. The rationale should be included in the report (if applicable, preferably via analytical analysis in the form of an Excel spreadsheet).

E3.2.2 Missing information

Where an E-Audit is missing data, such as, but not limited to:

the Ministry will require the owner/operator of the wind facility to obtain that missing data. The Ministry will typically require that the owner/operator provide this information within 60 days of the Ministry’s written request to do so.

E4 E-Audit flow chart

Figure 1: E-Audit overview (options 1 and 2): process flow chart

Download printer-friendly flowchart (PNG)

E5 I-Audit review process

E5.1 Complete submissions

If the I-Audit report is complete and demonstrates compliance with the Ministry’s sound level limits, the Director will inform the owner/operator of the wind facility, in writing, that the I-Audit report shows compliance with the Ministry’s sound level limits, and that no further action is required. Refer to section F, Appendix F7, for items which must be submitted with the audit.

The Ministry will also require that all Acoustic Audit reportsfootnote 12 be posted on the project website within 10 business days of the Acoustic Audit being submitted to the Director and District Manager. The Ministry expects the owner/operator to ensure that the Acoustic Audit reports, and any updates, remain available to the public on the project website for the life of the project.

If a tonal assessmentfootnote 13 indicates a tonal audibility value that exceeds 4 dB, the Ministry will require that a tonal penalty be applied at all Receptors in accordance with the penalties described in Annex C of ISO 1996-2, Reference [2]. In this case, the Ministry will assess compliance with the sound level limits based on whichever of the following is applicable:

If the I-Audit report is complete and demonstrates non-compliance with the Ministry’s sound level limits, the owner/operator of the wind facility will be required to submit a NAAP to the Director and the District Manager (please refer to Figure 2 in section E6 of this document). The owner/operator of the wind facility will usually be required to submit the NAAP within 60 days of receiving a written request from the Ministry to do so, or within a date agreed to by the Director and/or the District Manager. The Ministry will review and approve the NAAP.

The Ministry will typically require that the NAAP outline proposed mitigation measures (including timelines) to bring the wind facility into compliance with the Ministry’s applicable sound level limits. The NAAP will also be expected to include details about the completion and submission of a new I-Audit to the Ministry to verify that compliance has been achieved, following implementation of the mitigation measures.

E5.1.1 Notes on compliance

For the purposes of section E5.1 of this document, the Ministry will consider a wind facility to be in compliance if, for all point(s) of reception and/or measurement locations covered by the I-Audit, the measured sound level(s) is (are) less than or equal to the sound level limits as specified in section D6 of this document.

The Ministry will require that the I-Audit include a table summarizing the Point(s) of reception/measurement locations, as well as the rationale for why specific Point(s) of reception/measurement locations were chosen. Please refer to the table in section F, Appendix F3, for an example.

Where a NAAP is required, in the subsequent I-Audit report(s), the owner/operator of the wind facility will also be required to make a statement, with suitable rationale, indicating that the sound levels at all other Receptors identified in the Acoustic Assessment Report are in compliance with the applicable sound level limits.

E5.2 Incomplete submissions

If the I-Audit is incomplete, the owner/operator of the wind facility has the option to follow one of the three options set out below. Please also refer to Figure 2 in Section E6 of this document and Appendix F12. The options would allow the owner/operator to:

E5.3 Option 1: supplement audit results

Owner / operators of wind facilities may have measurement data that was not previously shared with the Ministry. The supplementary data may be sufficient to deem both I-Audits complete without further measurements. This option allows owners / operators to reassess the audit based on:

The revised audit can then be resubmitted to the Ministry.

E5.4 Option 2: combine audit results

If proceeding with this option, the Ministry will require the owner/operator of the wind facility to submit an interim report to the Ministry based on the partial information of the first I-Audit. This I-Audit will be required to include:

The Ministry will allow the owner/operator to combine the first I-Audit with the second I-Auditfootnote 14, as the Approval conditions typically require two I-Audits at receptor locations. The Ministry will require this combined I-Audit to be submitted by the due date for the second I-Audit that is set out in the Approval. These combined I-Audits will be considered to be one I-Audit. However, wind projects that are required to conduct two (2) I-Audits must submit two audits. Therefore, the owners/operators are required to conduct an additional I-Audit in accordance with this document when this option is used. The following examples describe the procedure in greater detail.

Example 1

If the combination of the two I-Audits provides:

the Ministry will consider the I-Audit to be complete, and will apply the same compliance criteria and considerations as set out in section E5.1 above.

Example 2

If the combination of the two I-Audits does not provides sufficient data to fulfil the minimum data requirements as detailed in the Approval, the Ministry will require the owner/operator to submit two I-Audits using the revised assessment methodology for I-Audits (RAM I-Audit) specified in section E5.5 below.

E5.5 Option 3: analysis parameters for the RAM I-Audit

Revised assessment methodology for I-Audits

For this option, the Ministry will require the owner/operator of the wind facility to undertake an assessment based on Part D of this document, and as modified below. As noted in Part D of this document, the wind facility sound level is based on the logarithmic (energy) subtraction of the sound level when the turbines are operational and sound level when the turbines are parked.

In this section, “Turbine” means a turbine that has the greatest predicted noise impact at the subject receptor/measurement location.

The following items describe the assessment parameters that the Ministry will apply to the RAM I-Audit analysis:

E5.5.1 RAM I-Audit reporting requirements
E5.5.2 Notes on compliance

If a tonal assessmentfootnote 16 indicates a tonal audibility value that exceeds 4 dB, then the Ministry will require that a tonal penalty be applied at all Receptors in accordance with the penalties described in Annex C of ISO 1996-2, Reference [2]. In this case, the Ministry will assess compliance with the sound level limits based on whichever of the following is applicable:

Option 1: Supplement I-Audits with existing data

Owners/operators have the option of revisiting existing data that they may not have already shared with the Ministry, and supplementing their I-Audits with this data in an effort to complete the I-Audits.

Option 2: Combine audit results

As noted in section E5.4 of this document, if the combination of the two I-Audits provides sufficient data to fulfil the minimum data requirements as detailed in the Approval, the Ministry will consider the I-Audit to be complete. The same compliance criteria and considerations set out in section E5.1 of this document for the I-Audit Review Process for Complete Submissions would therefore be applicable.

Option 3: analysis parameters for the RAM I-Audit

The Ministry will consider a wind facility to be in compliance if, for all Point(s) of reception and/or measurement locations covered by the RAM I-Audit, the measured sound level(s) is (are) less than or equal to the sound level limits as specified in section D6 of this document.

The Ministry will require a table summarizing the point(s) of reception/measurement locations, as well as the rationale for why specific point(s) of reception/measurement locations were chosen to be included in the RAM I-Audit. Please refer to the table in section F, Appendix F3, for an example.

As part of the RAM I-Audit report, the owner/operator of the wind facility will also be required to make a statement, with suitable rationale, indicating that the sound levels at all other Receptors identified in the Acoustic Assessment Report are in compliance with the applicable sound level limits.

If the RAM I-Audit report demonstrates compliance with the Ministry’s sound level limits, the Director will inform the owner/operator of the wind facility, in writing, that the RAM I-Audit report shows compliance with the Ministry’s sound level limits, and that no further action is required.

If the RAM I-Audit report demonstrates non-compliance with the Ministry’s sound level limits, the owner/operator of the wind facility will be required to submit a NAAP to the district office and the Director. The owner/operator of the wind facility will usually be required to submit the NAAP within 60 days of receiving a written request from the Ministry to do so, or within a date agreed to by the Director and\or District Manager. The Ministry will review and approve the NAAP.

The Ministry will typically require that the NAAP outline proposed mitigation measures (including timelines) to bring the wind facility into compliance with the applicable sound level limits. The NAAP will also be expected to include details about the completion and submission of a new I-Audit to the Ministry to verify that compliance has been achieved, following implementation of the mitigation measures.

E6 I-Audit flow chart

Figure 2: I-Audit flow chart (with 3 options)

Note: Only for audits which were originally required to be based on the 2011 protocol.

Download printer-friendly flowchart (PNG)

I-Audit complete

Are the I-Audit values acceptable? (Acceptable sound pressure values are ≤ 40 dBA at 6 m/s)

I-Audit not complete

Part F: Appendices

F1 Appendix A: Noise complaint form

Recommended interview questions:
Recommended complaint response procedures:

The following should be established:

Appendix F2: Overview of the qualitative assessment

The general steps identified in the qualitative assessment are included in the figure below:

Download printer-friendly flowchart (PNG)

Sample UTM analysis

SCB – corrected coordinates were adjusted 3 m in the Northing to adjust for the 1 m south setback and 2 m turbine base.

IDNoise assessment: Easting (m) Datum NAD 83Noise assessment: Northing (m) Datum NAD 83SCB – corrected coordinates : Easting (m) Datum NAD 83SCB – corrected coordinates : Northing (m) Adj Datum NAD 83Comparison: NA vs SCB
T45391879467892639187746789304.47
T46384831466844538483646684465.10
T47384190466981838419346698203.61
T48382940467058638294546705705.39
T49382658467090338266246709075.66
T50382029467160038203446716046.40
T51387019466781438702546678187.21
T5238675946681138676346681177.21
T53382926467381838293146738215.83
T54388889466753238889346675344.47
T553886534667799388621466780232.14 (this would require further follow-up to determine if it is a reduction > 4%)
T56387925466825838792946682594.12
T57387354466870938735746687102.83
T58384720467128938472546712936.53
T59384248467324338425246732434.00

Appendix F3: Sample rationale summary for measurement locations

For I-Audit purposes the Points of Reception should be selected such that they represent the location of the greatest predicted noise impacts, i.e. the highest predicted sound levels; subject to the documented constraints imposed by the location of the Points of Reception:

If the owner / operator cannot access the site(s) of one or more of the preferred Points of Reception, the owner / operator must:

Refer to the table on the next page for an example of a sample rationale summary table for measurement locations.

An example of a sample rationale summary table for measurement locations

Receptor IDDescription of receptorReceptor Height (m)footnote 18Distance to Closest Turbine (m)Closest Turbine IDModelled sound level(dBA)footnote 19Rationalefootnote 20
R3201Non-Participating receptor4.5561T239.9Permission Not Grantedfootnote 21
R3512Non-Participating receptor4.5621T3639.8Selected Monitoring Location
V6032Vacant Lot4.5632T439.8Poor Monitoring Location (e.g. close to trees, roads)
V6028Vacant Lot4.5661T639.7Selected Monitoring Location
R3456Non-Participating receptor4.5703T339.5Not in Prevailing Wind Direction
R3698Non-Participating receptor1.5612T839.4Poor Monitoring Location; farm noise prevalent
V6323Vacant Lot4.5599T939.3Permission Not Grantedfootnote 22
P3898Participating receptor4.5761T2038.9Selected Monitoring Location (PORs in the vicinity denied access to their property)footnote 23
M1footnote 24Measurement Location (Not a point of reception or Participating receptor)4.5550T1538.8Selected Monitoring Location. Location chosen close to the turbine, as Ambient sound levels at other locations were high.

Appendix F4: Resident triggered measurement form and example of results

Resident triggered measurement form

#DayDateTimeNoise Annoyance level,  rated on a scale of 1-10footnote 25Comments; to be completed by home owner
1WednesdayJuly 20, 20169:04 AMNot applicableset up test
2WednesdayJuly 20, 201610:02 AM6audible sound from wind turbine (WTG6) and  low background
3ThursdayJuly 21, 201611:05 PM2high wind speed at ground level, wind turbine noise very low
4FridayJuly 22, 20168:09 AM5car passing by at 8:12 AM, wind turbine noise noticeable from 8:00 AM to 8:15 AM
5SaturdayJuly 23, 201611:12 AM7Quiet background, audible noise from wind turbine (WTG2), continuous noise from 11:12 AM to 11:22 AM
6     
7     
8     
     
12     

Example of results 1

Measurements
#DateAudio recording activatedWind turbines & background sound, 10 min Leq (dBA)Wind turbines with exraneous noise, 10 min Leq (dBA)Compliance indicatedResident annoyance levelMinistry comments
1March 26, 20165:18 PM43.033.1Yes5Door closing, people talking
2March 26, 201610:20 PM36.036.0Yes6 
3March 27, 20167:57 AM38.836.1Yes3cow mooing
4March 27, 201610:08 PM45.239.1Yes5wind gusts
5March 28, 201612:03 AM43.738.2Yes7 
6March 28, 20162:51 AM44.139.8Yes8 
7March 28, 20162:23 PM43.939.2Yes8 
8March 28, 20162:46 PM49.439.8Yes8road traffic
9March 29, 20163:44 AM41.239.2Yes7wind
10March 31, 201610:02 PM45.340.1 7heavy rain
11March 31, 201610:29 PM45.535.6 9heavy rain
12April 1, 20164:03 AM44.133.8 7cat, strong wind

Example of results 2

First weather station at 1.5 m height (optional)
#Temp. °CHumidity (%)Wind speed (m/s)Wind direction (Clockwise; North is 0)Environmental validity (Yes/No)
12722.2243Yes
24844.3264Yes
36644.6266Yes
45654.912Yes
54716.1254Yes
66721.2302Yes
710742.618Yes
811784.2304Yes
9-6820.544Yes
1011951.7265No, high humidity
1111941.5243No, high humidity
124900.10No, high humidity
Second weather station at 4.5 m height (required for this receptor)
#Temp. °CHumidity (%)Wind speed (m/s)Wind direction (Clockwise; North is 0)Environmental validity (Yes/No)
12722.2243Yes
24844.3264Yes
36644.6266Yes
45654.912Yes
54716.1254Yes
66721.2302Yes
710742.618Yes
811784.2304Yes
9-6820.544Yes
1011951.7265.3No, high humidity
1111941.5243.2No, high humidity
124900.10No, high humidity
Power and wind data at hub height for wind turbing T01 (the closest wind turbine)
#% Power (MW)Average wind speed at hub height (m/s)Wind direction – YAW directionTonal? (Y/N) only if there is a concern for tonality of the wind turbine
14%4.212.1N
230%7.290.1N
320%4.5114.2N
4100%12.6106.5N
598%11.9108.0N
696%12.8112.1N
798%12.1157.4N
899%12.5160.7N
9100%12.5216.0N
1099%13.417.2N
1199%13.122.8N
1297%11.984.4N

Measurement at receptor for turbine, predicted level: dba, setback distance m

Download this sample chart (PNG)

This chart is a sample illustration of what measured data would look like in graph form when using instrumentation and software typically used for this actitvity as described throughout this document. The receptor for which the measurement applies would need to be specified, as well as the turbine of interest, followed by the predicted noise level and setback distance in meters. This type of graph would be created for all wind turbines within 1,000 metres of the receptor.

Appendix F5: E-Audit checklist for IEC 61400-11:2002+A1:2006

Wind Energy Project – Screening Document – Acoustic Audit Report – Emission, IEC61400-11 Standard

Note 1: If conducting the Acoustic Audit – Emission using IEC61400-11:2013 standard, please use the Acoustic Audit Report – Emission, IEC61400-11:2013 standard screening document (not this document).

Note 2: Comments should include which section of the report the information can be found.

1. Characterization of the Wind Turbine

Items 1 to 26; IEC61400-11:2002+A1:2006, Section 9.1, Characterization of the wind turbine

Operating details:
Rotor details:
Gearbox details:
Generator details:
2. Physical environment
3. Measurement instrumentation
4. Acoustic data

Items 40 to 49; IEC61400-11:2002+A1:2006, Section 9.4, Acoustic Data

5. Non-acoustic data
6. Uncertainty
7. Additional information

Appendix F6: E-Audit checklist for IEC 61400-11:2013

Wind Energy Project – Screening Document – Acoustic Audit Report – Emission, IEC61400-11:2013 Standard

Information required in the Acoustic Audit Report – emission

Note 1: If conducting the Acoustic Audit – Emission using IEC61400-11:2002+A1:2006 standard, please use the Acoustic Audit Report – Emission, IEC61400-11:2002+A1:2006 standard screening document (not this document).

Note 2: Comments should include which section of the report the information can be found.

1. Characterization of the wind turbine

Items 1 to 26; IEC61400-11:2013, Section 10.2, Characterization of the wind turbine

Operating details:
Rotor details:
Gearbox details:
Generator details:
2. Physical environment

Items 27 to 33; IEC61400-11:2013, Section 10.3, Physical Environment

3. Measurement instrumentation

Items 34 to 39; IEC61400-11:2013, Section 10.4, Instrumentation

4. Acoustic data

Items 40 to 52; IEC61400-11:2013, Section 10.5, Acoustic Data

For each relevant wind speed (k):

5. Non-acoustic data
6. Uncertainty

Items 62 to 64; IEC61400-11:2013, Section 10.7, Uncertainty

The uncertainty of the following reported acoustic quantities shall be assessed and reported:

7. Additional information

Optional information for the Acoustic Audit Report – Emission

8. Acoustic data

Items 68 to 72; IEC61400-11:2013, Section 10.5, Acoustic Data

9. Non-acoustic data

Items 73 to 74 are from IEC61400-11:2013, Section 10.6, Non-Acoustic Data

Appendix F7: I-Audit checklist

Wind Energy Project – Screening Document – Acoustic Audit Report – Immission

Information Required in the Acoustic Audit Report – Immission

Appendix F8: Potential data illustrations and equipment set up

Download potential data illustration option 1 (PNG)

Please contact EAASIBGen@ontario.ca for a description of this figure.

Download potential data illustration option 2 (PNG)

Please contact EAASIBGen@ontario.ca for a description of this figure.

Download potential data illustration option 3 (PNG)

Please contact EAASIBGen@ontario.ca for a description of this figure.

Appendix F9: Illustration of equipment set up

These photographs show what the microphone set-up would look like in the field from three different vantage points once installed. The microphone position shall be sufficiently away from any large reflecting surfaces (minimum of 5 meters recommended). This requirement does not apply if using a small vertical reflecting board attached to the building facade. The microphone should be located at a point near the receptor dwelling that is not shielded from the closest wind turbine noise (or wind facility). Wherever possible, the microphone should not be located near deciduous trees or foliage.

Download illustration 1 (JPEG)
Download illustration 2 (JPEG)
Download illustration 3 (JPEG)

Appendix F10: Example for section D1.3

If the wind direction at the measurement location has the potential to influence (30 dBA or greater) the ambient measurements (for instance a nearby roadway), then if appropriate, the measurements should be filtered accordingly.

For example, if a roadway has the potential to influence the ambient measurements, the Practitioner will need to exercise judgment with respect to filtering wind direction during the ambient measurements, if the roadway will not influence the background sound level when the turbines will have the greatest noise impact at the measurement location.

See example below. Filtering the ambient to exclude measurements when wind is blowing from the west may be required.

Download example figure for section D1.3 (JPEG)

This figure is an illustration of a noise receptor in relation to two wind turbines, and a nearby roadway that contributes to ambient noise levels. In order to determine the ambient noise level, the ambient noise measurements are carried out with turbines in the vicinity of the noise receptor parked. The parked turbines are those that, if operating, would contribute to or would likely contribute to the ambient noise levels.

If the wind direction at the measurement location has the potential to influence the ambient measurements (for instance a nearby roadway), then if appropriate, the measurements should be filtered accordingly.

For example, suppose two turbines are situated about 950 meters to the east of the sound measuring instrumentation. Located about 130 meters to the west is a road. If wind is blowing from the west, filtering the ambient to exclude measurements from the wind or the road may be required.

Appendix F11: Example for Section E5.5.2(10)

In unique circumstances, the Ministry will consider not only the individual turbine with the highest predicted impact at the subject receptor, but a group of turbines that represent the greatest contribution at the receptor. Greatest contribution means turbines that have sound pressure levels that are up to two (2) dB lower at the receptor/measurement location than the turbine with the highest predicted impact at the receptor/measurement location.

With reference to the diagram below, the above condition would be satisfied if the turbines are located as noted in the diagram. The turbine (T1) with the highest predicted impact at the subject receptor is located to the east of the receptor and turbines T2 and T3 are located further to the east of the receptor. Turbines T2 and T3 also have an impact similar to, but at most 2 dB less, than the turbine T1. In this scenario, all three turbines (T1, T2 and T3) can be considered in the analysis. Consequently, the aggregate downwind angle can also be incorporated into the analysis.

The angle between the outer turbines, (turbine 1 and turbine 3 in this example) should not exceed 45 degrees.

In addition, downwind conditions now exist when any of the turbines are deemed to be downwind. In this example, the condition will exist when the wind direction is between -45 degrees of turbine 3 to +45 degrees of turbine 1.

Download example figure for section E5.5.2(10) (JPEG)

This figure illustrates the location of a home and three wind turbines to the southeast. The purpose of this illustration is the show a unique scenario where the Ministry will consider not only the individual turbine with the highest predicted impact at the subject receptor, but a group of turbines that represent the greatest contribution at the receptor. Greatest contribution means turbines that have Sound pressure levels that are up to two (2) dB lower at the Receptor location than the turbine with the highest predicted impact at the Receptor location.

The following table illustrates another interpretation of the concept using four scenarios. The bolded numbers indicate the turbines that would qualify to be included in the assessment.

Scenario 1

Turbine IDTurbine’s impact at the receptor location (dBA)Total impact from all turbines at the receptor (dBA)
13839.8
23139.8
33139.8
42539.8
52539.8

Scenario 2

Turbine IDTurbine’s impact at the receptor location (dBA)Total impact from all turbines at the receptor (dBA)
13639.9
23539.9
33139.9
43039.9
52539.9

Scenario 3

Turbine IDTurbine’s impact at the receptor location (dBA)Total impact from all turbines at the receptor (dBA)
13539.4
23439.4
33439.4
42539.4
52239.4

Scenario 4

Turbine IDTurbine’s impact at the receptor location (dBA)Total impact from all turbines at the receptor (dBA)
13439.9
23339.9
333footnote 2639.9
43239.9
53239.9

With reference to the measurement location (vertex), only turbine configurations that are within an angle of 45 degrees can be considered in the assessment. The receptor building cannot shield the sound of the turbines.

Appendix F12: Summary of I-Audit Scenarios (Past, Present and Future Approvals)

All wind projects if required to conduct two (2) I-Audits at a location, must submit two I-Audits for that location.

Scenario #Status of projectStatus of auditsAvailable option(s)
1OperationalBoth submitted and both incompleteOption 1, 2 or 3
2OperationalOne submittedIf the submitted audit is incomplete use Option 1, 2 or 3; If the submitted audit is complete, then second audit to be conducted as per this document. (variant of Option 3)
3OperationalAudits not yet submittedOption 1, 2 or 3
4Non-operationalNot due until 6-12 months after the facility is operationalOption 3

Option 1: Supplement Audits with Existing Data (and assess in accordance with this document).
Option 2: Combining Audit Measurements, and conduct an additional Audit based on this document.
Option 3: Conduct two Audits in accordance with this document.

  • Type 1 sound level meter according to the IEC standard 61672-1 (2002), Reference [7].
  • Class 1 or Class 2 microphone systemsfootnote 7