(A) Definitions. For the purpose of this section the following definitions shall apply, unless the context clearly indicates or requires a different meaning. Terms used in this section but not defined below or in § 154.005 shall have the meaning ascribed to them by the American National Standards Institute (ANSI) or its successor body.
A-WEIGHTED SOUND LEVEL. The sound pressure level in decibels as measured on a sound level meter using the A-weighting network. The level so read is designated dB(A).
DAY-NIGHT AVERAGE SOUND LEVEL. The 24-hour energy average of the A-weighted sound pressure level, with the levels during the period of 10:00 p.m. to 7:00 a.m. the following day increased by 10 dB(A) before averaging.
EMERGENCY. Any occurrence or set of circumstances involving actual or imminent physical trauma or property damage which demands immediate attention.
EQUIVALENT A-WEIGHTED SOUND LEVEL or Leq. The constant sound level that, in a given situation and time period, conveys the same sound energy as the actual time-varying A-weighted sound. (For the purposes of this chapter, a time period of 24 hours shall be used, unless otherwise specified.)
IMPULSE SOUND. Sound of short duration, usually less than one second with an abrupt onset and rapid decay. Examples of sources of impulsive sound include explosions, drop forge impacts, and discharge of firearms.
NOISE DISTURBANCE. Any sound which endangers or injures the safety or health of humans or animals, annoys or disturbs a reasonable person of normal sensitivities, endangers or injures personal or real property, or exceeds the Maximum Permitted Sound Levels in the table found in division (E) of this section.
NOISE SENSITIVE ZONE. An area which contains noise-sensitive activities, such as but not limited to, operations of schools, libraries, churches, hospitals, and nursing homes.
PURE TONE. Any sound which can be distinctly heard as a single pitch or a set of single pitches.
RMS SOUND PRESSURE. The square root of the time averaged square of the sound pressure, denoted Prms.
SOUND. An oscillation in pressure, particle displacement, particle velocity or other physical parameter, in a medium with internal forces that causes compression and rarefaction of that medium.
SOUND LEVELS. The weighted sound pressure level obtained by the use of a sound level motor and frequency weighting network (for the purposes of this chapter, an A-weighted network), as specified by the American National Standards Institute.
SOUND PRESSURE. The instantaneous difference between the actual pressure and the average or barometric pressure at a given point in space, as produced by sound energy.
SOUND PRESSURE LEVEL. Twenty times the logarithm to the base of 10 of the ratio of the RMS sound pressure to the reference pressure of 20 micropascals (20x10-6 N/m2). The sound pressure level is denoted LP or SPL and is expressed in decibels.
VIBRATION. An oscillatory motion of solid bodies of deterministic or random nature described by displacement, velocity, or acceleration with respect to a given reference point.
(B) Prohibited acts.
(1) Noise disturbance prohibited. No person shall make, continue, or cause to be made or continued, any noise disturbance.
(2) Loading and unloading. Loading and unloading, opening, closing, or other handling of boxes, crates, containers, building materials, garbage cans, or similar objects shall be prohibited between the hours of 6:00 p.m. and 7:00 a.m. in such a manner as to cause a noise disturbance across a residential district boundary or within a noise sensitive zone.
(3) Construction. Operation of any tools or equipment used in construction, drilling, or demolition work shall be prohibited between the hours of 6:00 p.m. and 7:00 a.m. on weekdays or any time on Sundays or holidays, such that the sound therefrom creates a noise disturbance across a residential district boundary or within a noise sensitive zone, except for emergency work of public service utilities.
(4) Vibration. Operating any device that creates vibration which is above the vibration perception threshold of an individual at or beyond the property of the source shall be prohibited. For the purposes of this section, VIBRATION PERCEPTION THRESHOLD means the minimum ground or structure-borne vibrational motion necessary to cause a normal person to be aware of the vibration by such direct means as, but not limited to, sensation by touch or visual observation of moving objects.
(5) Noise sensitive zones. Creating any sound within any noise sensitive zone so as to disrupt the activities normally conducted within the zone shall be prohibited, provided that conspicuous signs are displayed indicating the presence of the zone.
(C) Exceptions.
(1) Emergency exceptions. The provisions in this section shall not apply to the emission of sound for the purpose of alerting persons to existence of an emergency, or the emission of sound in the performance of emergency work.
(2) Additional exceptions. The provisions in this section shall not apply to the following activities, provided that the activities are conducted in a legally accepted manner.
(a) Snow plowing, street sweeping, and other public works activities.
(b) Church bells, chimes and carillons.
(c) Lawn care and house maintenance that occurs between 9:00 a.m. and 9:00 p.m.
(D) Variances. An application for a variance from the provisions in this section may be submitted to the Zoning Board of Appeals. The owner or operator of equipment on the property shall submit a statement regarding the effects of noise from the equipment on the overall noise level in the area. The statement shall include a study of the background noise levels, predicted level of noise at the boundary line due to the proposed operation, and justification for the variance. Upon review of the request for a variance, the Zoning Board of Appeals may grant a variance where strict adherence to the permitted sound level would create unnecessary hardship and only if the variance will not create a threat to the health, safety, and welfare of the public. The Zoning Board of Appeals may impose conditions of operation when granting a variance.
(E) Maximum permitted sound levels by receiving zoning district. No person shall operate or cause to be operated any source of sound in such a manner as to create a sound level which exceeds the 1imits set forth for the receiving zoning district in the following table when measured at or within the property boundary of the receiving district. All measurements and designations of sound levels shall be expressed in day-night average sound levels (Ldn). The provisions of this division shall not apply to the activities covered by division (C).
Maximum Permitted Average A-weighted Sound Levels | |
Receiving Zoning District | Average Sound Level, dB(A) |
Residential
|
55
|
Commercial (not noise sensitive)
|
65
|
Commercial (noise sensitive)
|
55
|
Industrial
|
70
|
Notes:
a. Correction for tonal sounds. For any source of sound which emits a pure tone sound, the maximum sound level limits in the above table shall be reduced by 5 dB(A) where the receiving district is residential or commercial-noise sensitive.
b. Correction for impulsive or impact-type sounds. For any source of sound which emits an atypical impulsive or impact-type sound, the maximum sound level limits in the above table shall be reduced by 5 dB(A) where the receiving district is residential or commercial-noise sensitive.
c. Planned development. Where the receiving district is a Planned Development district, the applicable standard in the above table shall be based on the most noise sensitive use within the planned development.
(F) Measurement of sound. The Zoning Administrator shall be responsible for developing and promulgating testing methods and procedures. In performing this task, the Zoning Administrator may consult with outside specialists in the field of sound measurement and control.
(G) Permitted land use. No new or substantially modified structure shall be approved for construction unless the owner or developer of the land demonstrates that the completed structure and the activities associated with and on the same property as the structure will comply with the sound/noise standards set forth in this section at all times of full-scale operation of such activities.
(H) Applicability of city noise control regulations. The sound and noise standards set forth in this section are intended to be used chiefly as performance standards to assist the Planning Commission and other city officials in determining whether a proposed development will generate a noise disturbance. In contrast, the noise control regulations set forth in §§ 92.30 through 92.33 of this Code are intended to be used chiefly by police or health officials to regulate and/or curtail specific noise occurrences generated by an existing source.
(Ord. 92-005, passed 2-17-92) Penalty, see § 154.999