ASA S12.9 Part 7 PDF download

ASA S12.9 Part 7 – Quantities and Procedures for Description and Measurement of Environmental Sound, Part 7: Measurement of Low-frequency Noise and Infrasound Outdoors in the Presence of Wind and Indoors in Occupied Spaces

Part 7 of the ANSI/ASA S12.9 series describes cautions and unique techniques for measuring lowfrequencynoise (LFN) outdoors in the presence of wind. It is necessary to measure in wind for wind turbineprojects and for countless other industrial power and facilities where environmental wind speed cannot becontrolled or levels are specified under downwind conditions. The standard also describes a uniform andrepeatable methodology for documenting LFN levels and spectra indoors in occupied spaces where modalconsiderations are important. The principal concern outdoors is wind-induced noise (WIN) created by windsources alone. The best estimates for WIN versus wind speed are presented herein based on the literatureand special testing conducted by the working group for this standard. The standard is intended to definemethods for routinely observed or monitored measurements of infrasound and LFN (ILFN) with standardoff-the-shelf instrumentation, commercially available or special windscreens, and microphones appropriateto the task at hand. Following the standard methods should promote uniform, repeatable, and comparabledata from site to site.