All words used in this Article not defined below shall be in
conformance with applicable publication of the American National Standards
Institute (ANSI) or its successor body for the purpose of this Article.
The following words and phrases are defined and shall be construed
as defined below unless it shall be apparent from the context that
a difference meaning is intended.
The sound pressure level in decibels as measured on a sound
level meter using an A-weighting network. The level so read is designated
dBA.
The A-weighted sound pressure level of all the encompassing
noise associated with a given environment, being usually a composite
of sounds from many sources.
The Code Enforcement Officer of the City of Dardenne Prairie
or his duly authorized representative.
A unit for describing the amplitude of sound, equal to twenty
(20) times the logarithm to the base ten (10) of the ratio of the
pressure of the sound measured to the reference pressure, which is
twenty (20) micronewtons per square meter.
A work performed for the purpose of preventing or alleviating
physical trauma or property damage threatened or caused by an existing
or imminent peril. Emergency work may also be declared by the City
as outlined above.
For the purposes of this Article, the following days will
be recognized as holidays for the purpose of granting permits to exceed
maximum sound level: Memorial Day, Independence Day, Labor Day and
December 31.
An apparatus consisting of a series of chambers or baffle
plates designed for the purpose of transmitting gases while significantly
reducing sound emanating from such apparatus.
Any sound which annoys or disturbs humans or which causes
or tends to cause an adverse psychological or physiological effect
on humans.
Any sound using sound equipment, whose source is outside
or whose source is inside and the sound propagates to the outside
through open doors or windows or other openings in the building.
Any individual, association, partnership or corporation and
including any officer, employee, department, agency or instrumentality
of the United States, the State of Missouri or any political subdivisions
thereof.
Metering function to be used in measurement of sound for
determination of enforcement of the objective noise level limits stated
within this Article.
An oscillation in pressure, particle displacement, particle
velocity or other physical parameter, in a medium with internal forces
that cause compression and rarefaction of that medium resulting in
air pressure variations perceptible by the human ear. The description
of sound may include any characteristic of such sound, including duration,
intensity and frequency.
The unweighted ("flat") or weighted sound pressure level
obtained by the use of a sound level meter and frequency weighting
network, such A, B or C as specified in the American National Standards
Institute specifications for sound level meters (ANSI SI.4). If the
frequency weighting employed is not indicated, the A-weighting shall
apply.
Any instrument including a microphone, an amplifier, an output
meter and frequency weighting networks for the measurement of sound
pressure levels in a specified manner which complies with Type 2 of
better standards established in the ANSI SI.4-1971 "Specification
for Sound Level Meters."
Twenty (20) times the logarithms to the base ten (10) of
the ratio of the roof mean squared (RMS) sound pressure to the reference
pressure of twenty (20) micronewtons per square meter.
The location or property boundary receiving noise from a
sound source.
The location of property boundary from which a sound emanates.
For the purposes of enforcement of the allowable noise level
limits in this Article, sound level measurements shall be average
when possible and appropriate over a two-, eight-, or fifteen-minute
period. The measurement can be manual or by using a sound level meter
which includes an ANSI standard integration feature. The proper designation
for sound level measurements made using this technique is dBA LEQ
(Equivalent Level).
Districts established by the zoning ordinances of this City.
It shall be unlawful for any person to create or assist in creating,
permitting, continuing or permit the continuance of any loud, disturbing
or unnecessary noise in the City. Noise of such character, intensity
and duration as to be detrimental to the life or health of any individual
or to unreasonably disturb or annoy the quiet, comfort or repose of
any individual is prohibited. Noises which are the result of legally
operating businesses engaged in their normal operations are subject
to the objective noise level limits listed in this Article.
A.
The following acts, among others, are declared to be loud, disturbing
and unnecessary noises in violation of this Article, but such enumeration
shall not be deemed to be exclusive:
1.
The sounding of any horn or signal device or any device on any
automobile, motorcycle, bus or other vehicle while not in motion,
except as a danger signal if another vehicle is approaching apparently
out of control or, if in motion, only as a danger signal after or
as brakes are being applied and deceleration of the vehicle is intended;
the creation by means of any such signal device of any unreasonably
loud or harsh sound; and the sounding of such device for an unnecessary
and unreasonable period of time.
2.
The use of any gong or siren upon any vehicle other than law
enforcement, fire or other emergency vehicles.
3.
The use or operation of any piano, manual or automatic, phonograph,
radio, loudspeaker or any other instrument or sound-amplifying device
so loudly as to disturb persons in the vicinity thereof or in such
a manner as renders the same a public nuisance.
4.
The use of any automobile, motorcycle or other vehicle so out
of repair, so loaded or in such manner as to create loud or unnecessary
grating, grinding, rattling or other noise.
5.
The blowing of any steam whistle attached to any stationary
boiler, except to give notice of the time to begin or stop work or
as a warning of danger.
6.
The discharge into the open air of the exhaust of any steam
engine, stationary internal combustion engine or motor vehicle, except
through a muffler or other device which will effectively prevent loud
or explosive noises therefrom.
7.
The use of any mechanical device operated by compressed air,
unless the noise created thereby is effectively muffled and reduced.
8.
Construction or demolition-related activity in any zoning district
which results in a sound level created thereby in a residential zoning
district in excess of sixty-five (65) dbA (A-weighted sound pressure
level), when the noise emitted is measured at the nearest residential
property line to the property upon which the noise source is located,
other than between the hours of:
a.
On weekdays during the months of June, July and August: 6:30
A.M. to 6:00 P.M.
b.
On weekdays during the remaining months of the calendar year:
7:00 A.M. to 6:00 P.M.
c.
On Saturday: 8:00 A.M. to 6:00 P.M.
d.
On Sunday: 9:00 A.M. to 6:00 P.M.
provided this shall not apply in the case of urgent necessity
or in the interest of public safety and shall not be construed as
limiting or precluding the repair, maintenance or construction of
public facilities of the State, county or municipal governments, or
such public or quasi-public municipal corporations as may be established
under the Constitution or laws of the State of Missouri; the repair,
maintenance or construction of private utility facilities.
9.
The creation of loud and excessive noise in connection with
loading or unloading any vehicle or the opening and destruction of
bales, boxes, crates and containers.
10.
The sounding of any bell or gong attached to any building or
premises which disturbs the quiet or repose of persons in the vicinity
thereof.
11.
The shouting and crying of peddlers, barkers, hawkers and vendors
which disturbs the quiet and peace of the neighborhood.
12.
The use of any mechanical loudspeakers or amplifiers on trucks
or other moving vehicles for advertising purposes or other purposes.
13.
The conducting, operating or maintaining of any garage or filling
station in any residential district so as to cause loud or offensive
noises to be emitted therefrom between the hours of 11:00 P.M. and
7:00 A.M.
14.
Except as otherwise provided in Section 537.294, RSMo., the
firing or discharging of any gun, squibs, crackers, gunpowder or other
combustible substances in the streets or elsewhere for the purpose
of making noise or disturbance.
15.
The use or operation of any motor vehicle, any mechanically
operated device or internal combustion engine operated by fuel or
electric power in any race or event unless the noise created thereby
is effectively muffled and reduced by the use of a three-chamber muffler
or other device such that the noise does not exceed a noise level
of ninety-three (93) dbA (A-weighted sound pressure level) when the
noise emitted is measured upon property which is located in a different
land use category than the property upon which the noise source is
located; provided this applies to the total noise from a vehicle or
combination of vehicles and shall not be construed as limiting or
precluding the enforcement of any other provisions of this Article
relating to motor vehicle mufflers for noise control.
16.
The use, operation or permitting to be played, used or operated
any radio-receiving set, musical instrument, phonograph, loudspeaker,
sound amplifier or other machine or device for the producing or reproducing
of sound which is broadcast from the public streets for the purpose
of commercial advertising or attracting the attention of the public
to any building or structure that is determined to be excessive based
upon the criteria set out in this Article.
17.
Prolonged yelling, shouting, hooting or whistling on the public
streets, particularly between the hours of 10:30 P.M. and 7:00 A.M.
or at any time or place so as to annoy or disturb the quiet, comfort
or repose of persons of reasonable sensitivity in any office, dwelling,
hotel or other type of residence or of any persons in the vicinity.
18.
The keeping of any animal or bird on residential premises that
causes frequent or long continued noise which disturbs the comfort
or repose of any persons in the vicinity.
19.
Collection of solid waste in residential areas or commercial
areas adjacent to residential areas between the hours of 7:00 P.M.
to 6:00 A.M. Monday through Friday and 6:00 P.M. to 8:00 A.M. Saturday
or collect solid waste on Sunday.
A.
In the enforcement of standards established in this Article, the
Code Enforcement Officer may be required to exercise judgment in determining
if a particular noise is sufficiently loud or otherwise so offensive
that it would unreasonably disturb other persons in the vicinity.
When making such determinations, the Code Enforcement Officer shall
consider the following factors:
1.
The intensity (sound pressure level) of the noise.
2.
Whether the nature of the noise is usual or unusual.
3.
Whether the origin of the noise is natural or man-made.
4.
The volume and intensity of the background noise, if any.
5.
The proximity of the noise in residential sleeping facilities
during the sleeping hours of 10:30 P.M. to 7:00 A.M.
6.
The nature and zoning of the area within which the noise emanates.
7.
The time of the day or night along with the day of week and
time of year the noise occurs.
8.
The duration of the noise.
9.
Whether the noise is recurrent, intermittent or constant.
A.
This Section describes acceptable methods of techniques for the measurement
and reporting of noise for the purpose of determining compliance with
the allowable noise levels listed above.
1.
Measurement location. Measurement of sound must be made at the
front building line on the property of the noise receptor.
2.
Calibration. All sound level measuring devices must be calibrated
by a certified agency or the City.
3.
Sound level measurement shall be made with a sound level meter
using the A-weighting scale set on "slow" response.
4.
Sound level meters shall be at least Type SIA meeting American
National Standard Institute (ANSI S1.4-1971) requirements. Persons
using the sound levels shall be trained in sound level measurement
and the operation of sound level measurement equipment.
5.
Measurement procedures. The following procedures must be followed
to obtain representative sound level measurements.
a.
Measurement location must be at least three (3) feet above the
ground and not more than ten (10) feet above ground.
b.
Measurement shall be taken in location on receptor property
with line of sight to the noise source if possible.
c.
Measurements made in sustained winds over ten (10) knots may
be subject to review and considered not valid. Precipitation or other
sounds which result in a difference of less than ten (10) dBA between
the background or ambient noise level and the noise source being measured
may also invalidate measurements.
d.
Measurements must be made with the sound level meters set for
"A" weighting and "slow" response.
e.
Measurements are to be made when possible and appropriate to
the noise source over a two-, eight- or fifteen-minute period with
the sound level meter in the "averaging" or Leq mode or manual observations.
Measurements should be made over a continuous period, unless a transient
event which is easily identified, such as an aircraft overflight,
occurs. In this case, the averaging period may be paused for the duration
of the transient event and the measurement restarted when the transient
event sound level is ten (10) dBA below the noise source being measured.
6.
Date Documentation. A record of all sound level measurements
must be completed and signed by the person marking the measurements.
The record sheet should include:
a.
Date.
b.
Time of measurement.
c.
Location (street address if possible).
d.
Noise source.
e.
Wind speed and direction (measured, estimate or from airport
or weather service records).
f.
Temperature (if readily available).
g.
Humidity (if readily available).
h.
Make, model and serial number of sound level meter, date of
last certification/calibration.
i.
Field calibration results.
j.
Ambient (background) noise level.
k.
Name of complainant (if available).
A.
In addition to the subjective standards established above, it shall
be presumed that the allowable noise level limits have been violated
whenever any noise or sound is projected from one property in the
City onto another if such sound, measured at the front building line
on the property receiving the sound, exceeds the following decibel
standards at a location appropriate to determine the level of disturbance.
When the noise emitted is measured upon property which is located
in a different land use category than the property upon which the
stationary noise source is located, the levels applicable to the property
where the noise emitted is measured shall be used to determine if
a violation exists.
|
Objective Noise Standards — Allowable Levels
| |||
|---|---|---|---|
|
In residentially zoned districts
|
15 minutes
|
8 minutes
|
2 minutes
|
|
7:00 A.M. to 10:30 P.M.
|
59 dB to 61 dB
|
62 dB to 64 dB
|
68 dB to 70 dB
|
|
10:30 P.M. to 7:00 A.M.
|
54 dB to 56 dB
|
57 dB to 59 dB
|
63 dB to 65 dB
|
|
In commercially zoned districts
| |||
|
7:00 A.M. to 12:00 Midnight
|
69 dB to 71 dB
|
72 dB to 74 dB
|
78 dB to 80 dB
|
|
12:00 Midnight to 7:00 A.M.
|
64 dB to 66 dB
|
67 dB to 69 dB
|
73 dB to 75 dB
|
|
In industrially zoned districts
| |||
|
7:00 A.M. to 12:00 Midnight
|
74 dB to 76 dB
|
77 dB to 79 dB
|
83 dB to 85 dB
|
|
12:00 Midnight to 7:00 A.M.
|
74 dB to 76 dB
|
77 dB to 79 dB
|
83 dB to 85 dB
|
B.
Multifamily structures shall have the same noise limits between units
as for single-family or detached dwellings, as measured at any point
in the interior of the sound receptor residential unit with windows
closed.
A.
The following are exempt from the provisions above:
1.
Crowd sounds emanating from scheduled outdoor athletic events
and/or festivals, concerts and activities operating under permit from
the City.
2.
Noise of safety signals, warning devices, emergency pressure
relief valves.
3.
All church bells, church chimes, either actual or electronic,
or artificial sound reproduction system intended to sound like church
bells or chimes operated between the hours of 6:00 A.M. and 10:30
P.M.
4.
Noise resulting from any authorized emergency vehicle.
5.
Noise resulting from parades, lawful picketing or other public
demonstrations protected by the United States Constitution or Federal
law for which a local permit has been granted by the City, provided
such activity is of a temporary duration lasting no longer than two
(2) hours during any twenty-four-hour period. Regulation of noise
emanating from activities under permit shall be according to the conditions
and limits stated in this Section and according to any additional
conditions stated on the permit.
6.
Unamplified and amplified sound at public affairs conducted,
sponsored or sanctioned by the City of Dardenne Prairie, so long as
such sound remains within the parameters of this Article.
7.
All noises coming from the normal and legal operations of properly
equipped aircraft.
8.
Noise from noisemakers on holidays and fireworks on holidays
or at times allowed under a pyrotechnics permit.
9.
Noise from trains and associated railroad rolling stock when
operated in a proper manner.
10.
Emergency work as defined above.
11.
Special event permits. When approved by the Board of Aldermen,
the Code Enforcement Officer or his designated representative may
issue special event permits for events such as, but not limited to,
concerts, festivals, parades and athletic events to permit reasonable
and limited exceptions to the provisions of this Article. Any special
event permit issued shall contain specific provisions as to the activities
which will be conducted and dates and times during which the provisions
of this Article are to be suspended. Specific sources to the noise
which may exceed the established sound limits shall be identified
with projected or estimated noise levels, and special conditions may
be established in the permit which will minimize the noise impact
of the special event on the community.
Any condition detrimental to the public health, safety, morals
or welfare and in violation of this Article is declared to be a public
nuisance, and it shall be unlawful for any person, including the owner
or occupant of any premises within the boundaries of the City and
within one-half (1/2) mile of the boundaries thereof, to maintain
or permit to be maintained such public nuisance.
A.
If the alleged violator denies responsibility for the noise level
problem or if the Code Enforcement Officer or his designee is not
able to amicably abate the noise level problem, he shall issue a notice
to the person responsible for such noise level problem which shall
specifically state the facts of the violation and the provisions of
this Article violated; and he shall require such person to answer
the allegations contained in such notice at a hearing before the Code
Enforcement Officer or his designee to be held not less than seven
(7) days after the date of such notice.
B.
If the respondent to such notice of violation desires to offer evidence
at the hearing, he shall file a written answer thereto with the Code
Enforcement Officer or his designate not less than two (2) days before
the hearing at the Dardenne Prairie City Hall, setting forth a summary
of the facts and evidence to be presented at the hearing, in default
whereof the facts stated in the notice of violation shall be deemed
by the Code Enforcement Officer or his designee to be true; and if
he finds that adequate corrective measures will not be employed to
abate the noise level.
C.
After due consideration of all matters at the hearing, or upon the
default in appearance of the alleged violator, and if he finds that
adequate corrective measures will not be employed to abate the noise
level, the Code Enforcement Officer or his designee shall make such
determinations and issue such orders as are appropriate and commensurate
with the provisions of this Article, and he shall forthwith give notice
thereof in writing to the alleged violator.
D.
The Code Enforcement Officer or his designee, upon determination
of a violation of this Article after such hearing is conducted, may
proceed to sign a complaint form at the Police Department of the City,
and should the City Prosecutor decide to proceed with such signed
complaint, a summons will be issued which is returnable in the Dardenne
Prairie Municipal Court.
E.
Any person determined to be in violation of any provision of this
Article shall, upon conviction, be assessed a fine of up to five hundred
dollars ($500.00). Each day of such violation shall constitute a separate
violation.
