§ 30-82. Definitions.

The following terms used in this article are defined as follows:

dB(A) means the sound pressure level in decibels measured on the "A" scale of a standard sound level meter having characteristics defined by the American National Standards Institute, Publication ANSI S1.4-1971.

Decibel is a unit to express the magnitude of sound pressure and sound intensity. The difference in decibels between two sound pressures is 20 times the common logarithm of their ratio. In sound pressure measurements, the sound pressure level of a given sound is defined to be 20 times the common logarithm of the ratio of that sound pressure to a reference pressure of 2 x 10 ^-5 N/m ² (Newtons per meter squared). As an example of the effect of this formula, a three decibel change in the sound pressure level corresponds to a doubling or halving of the sound intensity, and a ten decibel change corresponds to a ten-fold increase or decrease to one-tenth the former intensity.

(Ord. No. 208, Art I, 9-5-17)