FMR’s overall mission profile reflects the following operational footprint components:
Noise
Safety
Weapon Surface Danger Zones
Explosive Safety Quantity Distance Arcs
Restricted Airspace
Noise
Understanding Noise
Due to the technical nature of this topic and its importance to the JLUS process, this
section discusses the characteristics of sound and the modeling process used to evaluate
noise impacts. The following key terms are used to describe noise.
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Ambient Noise. The total noise associated with an existing environment, which
usually includes sounds from many sources, both near and far.
A‐weighted decibel. The A‐weighted decibel (dBA) is the most commonly
weighted sound filter used to measure perceived loudness, versus actual sound
intensity by the human ear. The human ear responds differently to varying
frequencies. For example, the human hearing system perceives mid‐frequency
sounds as louder than low‐ and high‐frequency sounds. To accommodate this
condition when measuring sound levels, filters need to be installed into sound
meters. The results are a more accurate measurement of sound for the human
hearing system.
C‐weighted decibel. The C‐weighted decibel (dBC) scale is often used to
characterize low‐frequency sounds capable of inducing vibrations in buildings or
other structures. It is commonly used by the DoD to characterize large arms and
demolitions noise levels.
Decibel. A decibel (dB) is a unit used to measure the intensity of a sound by
comparing it with a given level on a logarithmic scale.
Noise contour. A noise contour is a line made by connecting points in space
with equal noise exposure.
Noise‐sensitive use. A noise‐sensitive use is a location or type of land use
typically more susceptible to impacts from noise. Examples include residential
developments, hospitals, convalescent homes and facilities, schools, libraries,
churches, recreational areas, and other similar uses.
Arizona Army National Guard Profile