precipitation would affect the measurement results. Wind speeds are the ones at which the wind turbine is shown to produce the highest sound level based on vendor testing. 5. Infrasound Infrasound Level Limits No wind turbine(s) produce an infrasound pressure level, which is 6 dB higher than the background infrasound pressure level at the primary blade pass frequency and blade-pass frequency harmonics. All measurements are taken on any protected adjacent residentially used property. Measurements inside a building or residence may be performed assuming the building owner allows access. Measurement Personal Qualifications i All persons conducting sound pressure measurements to assess compliance with this standard shall be trained in the current techniques and principles of sound measurement equipment and instrumentation, and shall take such measurements under the supervision of a qualified acoustical engineer as described herein. ii A qualified acoustical engineer shall be either a degreed engineer practicing acoustical engineering for 10 years or more as long as the engineer works for a firm that is a member of the National Council of Acoustical Consultants (NCAC), a board-certified member of the Institute of Noise Control Engineering (INCE Bd. Cert.) or a licensed professional engineer (PE) with an acoustical focus. Instrumentation i Infrasound pressure level measurements shall be performed with appropriate equipment that is properly calibrated to industry standards, as described below. The microphone shall have a frequency response that is less than or equal to 0.5 hertz (i.e. an infrasonic microphone). The measurement system shall be able to collect electrical signals from the microphone and perform a Fast Fourier Transform (FFT) of the signal with a frequency range of 0 to 20 hertz with a resolution of 0.1 hertz or less (≥ 200 lines). ii The instrumentation shall also be compatible to a Type 1 sound level meter. All test instrumentation shall be field calibrated with acoustic calibrator or
precipitation would affect the measurement results. Wind speeds are the ones at which the wind turbine is shown to produce the highest sound level based on vendor testing. 5. Infrasound Infrasound Level Limits No wind turbine(s) produce an infrasound pressure level, which is 6 dB higher than the background infrasound pressure level at the primary blade pass frequency and blade-pass frequency harmonics. All measurements are taken on any protected adjacent residentially used property. Measurements inside a building or residence may be performed assuming the building owner allows access. Measurement Personal Qualifications i All persons conducting sound pressure measurements to assess compliance with this standard shall be trained in the current techniques and principles of sound measurement equipment and instrumentation, and shall take such measurements under the supervision of a qualified acoustical engineer as described herein. ii A qualified acoustical engineer shall be either a degreed engineer practicing acoustical engineering for 10 years or more as long as the engineer works for a firm that is a member of the National Council of Acoustical Consultants (NCAC), a board-certified member of the Institute of Noise Control Engineering (INCE Bd. Cert.) or a licensed professional engineer (PE) with an acoustical focus. Instrumentation i Infrasound pressure level measurements shall be performed with appropriate equipment that is properly calibrated to industry standards, as described below. The microphone shall have a frequency response that is less than or equal to 0.5 hertz (i.e. an infrasonic microphone). The measurement system shall be able to collect electrical signals from the microphone and perform a Fast Fourier Transform (FFT) of the signal with a frequency range of 0 to 20 hertz with a resolution of 0.1 hertz or less (≥ 200 lines). ii The instrumentation shall also be compatible to a Type 1 sound level meter. All test instrumentation shall be field calibrated with acoustic calibrator or
ORC040518minutes.docx