StART Oct 23 2019 ground noise presentation 003

 Aircraft Noise Effects on Human Activity  Sound Propagation  Ground Noise Study Scope  Ground Noise Sources Input  Noise Monitoring Discusssion Acoustical Terminology  Maximum A-weighted Sound Level (Lmax)  Sound Exposure Level (SEL)  Equivalent Sound Level (Leq) Aircraft Noise Effects on Human Activity  Speech interference may occur • Outdoors with sound levels of 60 – 65 dBA outdoors or higher • Indoors with windows open at sound levels of 70 – 75 dBA outdoors or higher (outdoor to indoor level reduction is approximately 15 dB with open windows) • Indoors with windows closed at sound levels of 75 – 80 dBA outdoors or higher (outdoor to indoor level reduction is approximately 25 dB with closed windows)  Sleep interference may occur for ~ 2 % of people • With windows open and exterior sound levels of 70 to 75 dBA, Lmax • With windows closed and exterior sound levels of 80 to 85 dBA, Lmax Sound Propagation  Spherical Spreading • Sound level decreases by 6 dB per doubling of distance • Additional losses due to atmospheric absorption  Ground Effect • Sound levels are lower when reflected off of soft ground vs. hard ground Sound Propagation  Refraction due to Temperature • Gradients in temperature cause the bending of sound paths • Sound bends upward during a temperature lapse (cool air over warm) • Sound bends downward during a temperature inversion (warm air over cool) Sound Propagation  Refraction due to Wind •…

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PSCAA Advisory Council Meeting Agenda
Add to CalendarMWednesday Mar 11, 9:00am - 11:35am
1904 3rd Avenue, Suite 105, Seattle, WA 98101
Call to order – Roll Call – Quorum Established – Land Acknowledgement We would like to acknowledge that our Agency operates in four present-day counties, which are the traditional lands of the Coast Salish people, past and present. This acknowledgement does not take the place of authentic relationships with indigenous communities in our jurisdiction and [...]