The concise, scientific definitions of the terms used in § 95.06 shall be as follows.
A-WEIGHTED SOUND LEVEL. The sound pressure level of a sound measured through an A-weighting filter network. The level read is designated dB(A) or dBA.
DECIBEL (dB). The unit used for comparing the sound pressure level of a sound to the sound pressure level of a reference sound having a sound pressure of 20 micropascals.
FREQUENCY. The number of periodic oscillations, vibrations or waves per unit time (usually one second).
HERTZ (Hz). The unit used for measuring the frequency of a sound. The number of HERTZ is the number of cycles per second of a periodic sound pressure wave.
OCTAVE BAND. A portion of the entire sound frequency spectrum contained between two frequencies “a” and “b” such that a = 2b.
SOUND PRESSURE LEVEL. Twenty times the logarithm (base 10) of the ratio of the measured sound pressure to a reference of 20 micropascals. The sound pressure level is expressed in decibels (dB).
SPL = 20 LOG 10 sound pressure a
sound pressure b
sound pressure a = measured sound pressure
sound pressure b = reference sound pressure
(20 micropascals)