§ 22-151. Maximum permissible sound levels.

(a)

Continuous sound. No person shall cause, suffer, allow, or permit the operation of any source of sound on any source property listed in section 22-93(a) in such a manner as to create a sound level that exceeds the sound level limits listed in the following table I, as measured at any location at or within the property line of the receptor property. Sound pressure levels in excess of those established in table I shall constitute prima facie evidence that such sound is in violation of this article.

TABLE I. MAXIMUM PERMISSIBLE SOUND LEVEL LIMITS

Residential: 7:00 a.m. to 10:00 p.m. Noise sensitive: 24 hours	60.00 dB(A)
Residential: 10:00 p.m. to 7:00 a.m.	50.00 dB(A)
Commercial: 24 hours	65.00 dB(A)
Industrial: 24 hours	70.00 dB(A)

 

(b)

Impulsive sound.

(1)

Between 7:00 a.m. and 10:00 p.m., impulsive sounds which occur less than ten times in an hour shall not equal or exceed 20 decibels above the permissible sound level limits in table I. Impulsive sound which repeats ten or more times in any hour shall not exceed the permissible sound level limits in table I.

(2)

Between the hours of 10:00 p.m. and 7:00 a.m., impulsive sounds which occur less than four times in an hour shall not equal or exceed 20 decibels above the permissible sound level limits in table I. Impulsive sound which repeats four or more times in any hour shall not exceed the permissible sound level limits in table I.

(c)

Amplified sound. If the source of sound is an amplified sound reproduction device, and the complainant states that the rhythmic bass component of the music is disturbing within his residence, then the noise control officer may take sound level measurements within the residence of the complainant. No person shall cause, suffer, allow, or permit the operation of any amplified source of sound in such a manner that it exceeds the total sound levels by the permissible sound levels limits set forth in the following table II, when measured within the residence of a complainant. These sound level measurements shall be conducted with the sound level meter set for C-weighting, "fast" response. Such measurements shall not be taken in areas which receive only casual use such as hallways, closets and bathrooms. For the purposes of these measurements, the ambient sound level is that sound level which is measured in the residence when the sound source under investigation is not prominent, or in a room on the same floor that is relatively unaffected by the sound source under investigation The "C" scale is more sensitive to low frequency sound levels than the "A" scale, and an increase of five dB is perceived by humans as being plainly louder, and a ten dB increase is perceived as being twice as loud. Examples of amplified sound reproduction devices include but are not limited to sound systems which augment music or voices such as those used for public announcements or as utilized by disc jockeys in playing music.

TABLE II. AMPLIFIED SOUND REPRODUCTION DEVICE MAXIMUM PERMISSIBLE SOUND LEVEL LIMITS
Indoors Across a Real Property Line;
dB(C) Above Ambient

Weeknights: 10:00 p.m. to 7:00 a.m. Weekend nights: 11:00 p.m. to 9:00 a.m.	3 dB(C)
All other times	5 dB(C)

 

(d)

Steady pure tones. If the sound source under investigation is a mechanical device, and is, in the investigating officer's opinion, emitting a sound with a steady tonal quality, the permissible sound level limits in table I shall be reduced by five dB(A). The sound emissions must be composed of a single frequency or a narrow cluster of frequencies, which may be referred to as a whine, hum or buzz. The measured sound levels of such a source must not fluctuate by more than plus or minus three dB. Such sound sources include, but are not limited to, heating, ventilating or air conditioning units, refrigeration units, and transformers. Nothing to the contrary withstanding, sound sources from residential heating, ventilating or air conditioning units cannot exceed 55 dB(C) at night.

(Ord. No. 2000-033, § 1(VI), 4-4-2001)