81-80 ORDINANCE NO. 81-80
AN ORDINANCE OF THE CITY COUNCIL OF THE CITY OF DELRAY
BEACH, FLORIDA, AMENDING CHAPTER 16 "OFFEN~ES-MISCELLA-
NEOUS", ARTICLE II, "NOISE" OF THE CODE OF ORDINANCES OF
THE CITY OF DELRAY BEACH, FLORIDA, BY REPEALING SECTIONS
16-33, 16-34 AND 16-35 AND ENACTING A NEW ARTICLE II,
"NOISE CONTROL" PROVIDING FOR THE CONTROL OF SOUND AND
VIBRATION ORIGINATING WITHIN THE LIMITS OF THE CITY OF
DELRAY BEACH, FLORIDA; PROVIDING FOR DEFINITIONS; PRO-
VIDING FOR THE .PROHIBITION OF NOISE DISTURBANCE AND
DECLARING CERTAIN ACTS TO BE UNLAWFUL; PROVIDING FOR
EMERGENCY EXCEPTIONS AND SPECIAL VARIANCES; PROVIDING FOR
MAXIMUM PERMISSIBLE SOUND LEVELS BY RECEIVING LAND USE;
PROVIDING FOR PENALTIES FOR VIOLATIONS; PROVIDING FOR
ABATEMENT ORDERS AND NOTICES OF VIOLATION; PROVIDING FOR
NOT PROHIBITING CITIZEN SUITS; PROVIDING A SAVING CLAUSE;
PROVIDING FOR THE REPEAL OF ORDINANCES IN CONFLICT HERE-
WITH; PROVIDING AN EFFECTIVE DATE.
$'~EREAS, excessive sound and vibration are a serious hazard to the
public health and welfare, safety and the quality of life; and,
WHEREAS, the substantial body of science and technology exists by
which excessive in sound and vibration may be substantially abated; and,
W~EREAS, the people have a right to and should be ensured an environ-
ment free from excessive sound and vibration that may jeopardize.their
health or welfare or safety or degrade the quality of life; and,
WHEREAS, the City Council of the City of Delray Beach, Florida, de-
sires to prevent such excessive sound and vibration as would jeopardize
the'health and welfare or safety of its citizens or degrade the quality of
life,
NOW, THEREFORE, BE IT ORDAINED BY THE CITY COUNCIL OF THE CITY OF
DELRAY BEACH, FLORIDA, AS FOLLOWS:
Section 1. That Chapter 16 "Offenses-Miscellaneous", Article II
"Noise", is hereby amended by Yepealing Sections 16-33, 16-34, and 16-35,
and enacting.a new Article II "Noise Control" to read as follows:
Sec. 16-33. Scope.
This article shall apply to the control of all sound and vibration
originating within the limits of the City of Delray Beach, Florida.
Sec. 16-34. Definitions.
All t~rminology as used in this article, and not otherwise defined
below, shall be in conformance with the applicable publications of the
American National Standards Institute (ANSI) or its successor body.
As used in this article, unless otherwise defined or required by the
contents, the following words and phrases shall have the meaning indicated:
(1) "A-Weighted sound level" means the sound pressure level in deci-
bels as measured on a sound level meter using the A-Weighting Network.
The level so read is designated dB(A) or dBA.
(2) "Commercial area" means ail that area located in the following
zoning districts: Neighborhood Commercial District (NC), Community
Commercial District (CC), General Commercial District (GC), Specialized
Commercial District (SC), Central Business District (CBD), and Limited
Commercial District (LC).
(3) "Construction" means any site preparation, assembly, erection,
substantial repair, alteration, or similar action, but excluding demoli-
tion, for or of public or private rights-of-way, structures, utilities, or
similar property.
(4) "Day-night average sound level (L~,)" means the 24-hour energy of
the A-weighted sound pressure level, with ~e levels during the period
10:00 P.M. to 7:00 A.M. the following day increased by ten dBA before
averaging.
(5) "Decibel (dB)" means a unit for measuring the volume of a sound,
equal to twenty times the logarithm to the base 10 of the ratio of the
pressure of the sound measured to the reference pressure, which is 20
micropascals (20 micronewtons per square meter).
(6) "Demolition" means any dismantling, intentional destruction or
removal of structures, utilities, public or private right-of-way surfaces,
or similar property.
(7) "Emergency" means any occurrence or set of circumstances involv-
ing actual or imminent physical trauma or property damage which demands
immediate action.
(8) "Emergency work" means any work performed for the purpose of
preventing or alleviating the physical trauma or property damage
threatened or caused by an emergency.
(9) "Environmental Protection Officer/Noise Control Officer (EPO/NCO)"
means the City Manager of the City of Delray Beach or his designated
agent, who shall have the lead responsibility for this ordinance.
(10) "Equivalent A-Weighted sound-level (L )" means the constant
· . eq
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 pur-
poses of this ordinance, a time period of 24 hours shall be used, unless
otherwise specified.
(11) "Impulsive sound" means 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 the
discharge of firearms.
(12) "Industrial area" means all that area located in the following
zoning districts: Light Industrial District (LI) and Medium Industrial
District (MI).
(13) "Motor carrier vehicle engaged in interstate commerce" means any
vehicle for which regulations apply pursuant to Section 18 of the Federal
Noise Control Act 1972 (P.L.92-574), as amended, pertaining to motor
carriers engaged in interstate commerce.
(14) "Motor vehicle" means any vehicle which is propelled or drawn on
land by a motor, such as, but not limited to, passenger cars, trucks,
truck-trailers, semi-trailers, campers, go-carts, snowmobiles, amphibious
craft on land, dune buggies, or racing vehicles, but not including motor-
cycles.
(15) "Motorboat" means any vessel which operates on water and which is
propelled by a motor, including, but not limited to, boats, barges, amphi-
bious craft, water ski towing devices and hover craft.
(16) "Motorcycle" means an unenclosed motor vehicle having a saddle
for the use of the operator and two or three wheels in contact with the
ground, including, but not limited to, motor scooters and minibikes.
(17) "Muffler or sound dissipative device" means a device for abating
the sound of escaping gasses of an internal combustion engine.
(18) "Noise" means any sound which annoys or disturbs humans or which
causes or tends to cause adverse psychological or physiological effect on
humans.
-2- Ord. No. 81-80
(19) ."Noise disturbance" means any sound which (a) endangers or in-
jures the safety or health of humans or animals, or (b) endangers or
injures personal or real property.
(20) "Noise sensitive zone" means any area within the City of Delray
Beach, Florida, designated by the City as such, for the purpose of en-
suring quiet.
(21) "Person" means any individual, association, partnership, or
corporation, and includes any officer, employee, department, agency or
instrumentality of a State or any political subdivision of a State.
(22) "Powered model vehicle" means any self-propelled airborne, water-
borne, or land-borne plane, vessel, or vehicle which is not designed to
carry persons, including, but not limited to, any model airplane, boat,
car, or rocket.
(23) "Public right-of-way" means any street, avenue, boulevard, high-
way, sidewalk or alley or similar place which is owned or controlled by a
governmental entity.
(24) "Public space" means any real property or structures thereon
which are owned or controlled by a governmental entity.
(25) "Pure tone" means any sound which can be distinctly heard as a
single pitch or a set of single pitches. For the purposes of this arti-
cle, a pure tone shall exist if the one-third octave band sound pressure
level in the band with the ton~ exceeds the arithmetric average of the
sound pressure levels of the two contiguous one-third octave bands by five
decibel dB for center frequencies of 500'Hz and above and by eight decibel
dB for center frequencies between 60 and 400 Hz and by fifteen decibel dB
for center frequencies less than or equal to 125'Hz.
(26) "Real property boundary" means an imaginary line along the ground
surface, and its vertical extension, which separates the real property
owned by one person from that owned by another person, but not including
intra-building real property divisions.
(27) "Residential area" means all that area located in the following
zoning districts: R-1AAA, R-iAAA-B, R-i~A, R-1AA-B, R-lA, R-lA-B, RM-6,
RM-10, ~4-15, PRD-4, PRD-7 and PRD-10. '~
(28) "RMS sound pressure" means the square root of the time average
square of the sound pressure, denoted P
rms
(29) "Sound" means 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. The de-
scription, of sound may include any characteristic of such sound, including
duration, intensity and frequency.
(30) "Sound level" means the weighted sound pressure level obtained by
the use of a sound level meter and frequency weighting network, such as A,
B, or C as specified in American National Standards Institute specifi-
cations for sound level meters (ANSI S1.4-1971 or the latest approved
revision thereof). If the frequency weighting employed is not indicated,
the A-weighting shall apply.
(31) "Sound, level meter" means an instrument comprising a microphone,
amplifier, and output meter, and frequency-weighting networks, that is
used for the measurement of sound levels in a specified manner.
(32) "Sound pressure" means a measure of sound power, usually given in
dynes per square centimeter.
-3- Ord. No. 8-1-80
(33) "Sound pressure level (in decibels)" means twenty times the
logarithm to the base of.ten of the ratio of the pressure of the ~ound
being measured to a reference sound pressure of 20 micronewtons/m- or
0.0002 microbars.
(34) "Sound reproduction device" means a device intended primarily for
the production or reproduction of sound including, but not limited to, any
musical instrument, radio receiver, television receiver, tape recorder,
phonograph or sound amplifying system.
(35) "Sound signal device" means a device designed to produce a sound
signal when operated, including, but not limited to, any klaxon, airhorn,
whistle, bell, gong, siren, but not an emergency signal device.
(36) "Warning device" means sound emitting devices used to alert and
warn people.
(37) "L~0" means the sound level exceeded one-half (%) the time for
.the duratio~ of the measurement period.
Sec. 16-35. Noises prohibited.
(A) It shall be unlawful for any person to make, continue, or cause
to be made or continued any noise disturbance. Non-commercial p~blic
speaking and public assembly activities conducted on any public space or
public right-of-way shall be exempt from the operation of this section.
(B) The following acts, and the causing thereof, among others, are
declared to be unlawful and in violation of this ordinance:
(1) Radios, television sets, musical instruments and similar devices.
Operating, playing or permitting the operation or playing of any
radio, television, phonograph, drum, musical instrument, sound
amplifier, or similar device which produces, reproduces, or
~mplifies sOund:
(a) In such a manner as to create a noise disturbance within a
noise sensitive zone or at any time which violates the
provisions of Section 16-36 (except for activities open to
the public and for which a permit has been issued by the
City of Delray Beach according to criteria set forth in
Section 16-35(D));
(b) This section shall not apply to non-commercial spoken
language covered under Section 16-35(B)(2), below~.
(2) Loudspeakers/public address systems. Using or operating for any
purpose any loudspeaker, public address system, or similar device
such that the soUnd therefrom creates a noise disturbance within
a noise sensitive zone, or at any time which violates the provi-
sions of Section 16-36.
(.3) Street Sales. Offering for sale or selling anything by shouting
or outcry within any residential or commercial area of the City
(except by permit issued by the City according to criteria set
forth in Section 16-35(D) and/or except between the hours of 8:00
A.M. and 5:00 P.M..I, or at any time which violates the provisions
of Section 16-36.
(4) Animals and birds. Owning, possessing or harboring any animal or
bird which frequently or for continued duration, howls, barks,
meows, squawks, or makes other sounds which create a noise dis-
turbance within a noise sensitive zone, or at any time which
violates the provisions of Section 16-36. This provision shall
not apply to public zoos.
-4- Ord. No. 81-80
(5) Loading and unloading. Loading, unloading, opening, closing or
other handling of boxes, crates, containers, building materials,
garbage cans, or similar objects in such a manner as to cause a
noise disturbance within a noise sensitive zone, or at any time
which violates the provisions of Section 16-36.
(6) Construction. Operating or permitting the operation of any tools
or equipment used in construction, drilling, or demolition work
such that the sound therefrom creates a noise disturbance within
a noise sensitive zone or which violates the provisions of
Section 16-36.
(a) The provisions of this Subsection shall not prohibit con-
struction, drilling, or demolition work between the hours of
7:00 A.M. and 7:00 P.M. on weekdays, nor prohibit the use of
any temporary pumps or machinery which are required to be
operated 24 hours a day in conjunction with construction
work. This Subsection shall also not apPly to emergency
work for public utilities or %;here a special variance has
been issued pursuant to Sections 16-35(C) or 16-35(D).
(b) This section shall not apply to the use of domestic power
tools subject to Section 16-36(B)(16).
(7) Vehicle or motorboat repairs and testing. Repairing, rebuilding,
modifying, or testing any motor vehicle, motorcycle, or motor-
boat in such a manner as to cause a noise disturbance within a
noise sensitive zone, or at any time which violates the provi-
sions of Section 16-36.
(8) Refuse collection vehicles. No person shall collect refuse with
a refuse collection vehicle between the hours of 7:00 P.M. and
6:00 A.M. of the following day in a residential area or noise
sensitive zone, or in any other area which violates the provi-
sions of Section 16-36 between the hours of 7:00 P.M. and 6:00
A.M. of the following day.
(9) Stationary mechanical noise source. Operating or permitting the
operation of stationary mechanical sources including pumps,
motors, fans, compressors, powered tools or similar devices, but
not includiqg air conditioning or air-handling systems situated
in residential areas, but including cooling towers, in such a
manner as violate the provisions of Section 16-36, except for
pumping done pursuant to Section 16-35(B)(6)(a).
(10) Powered model vehicles. Operating or permitting the operation of
powered model vehicles between the hours of 8:00 P.M. and 7:00
A.M. the following day. Maximum sound levels during the per-
mitted period of operation shall conform to those set forth for
residential land use in Section 16-36(A) and shall be measured at
a distance of 100 feet from any point on the path of the vehicle.
Maximum sound levels for residential property and noise sensitive
zones, during the permitted period of operation, shall be governed
by Section 16-36.
(11) Vibration. Operating or permitting the operation of any device
on a property that causes a vibration which exceeds the accelera-
tion values given in Table A below on a receiving property:
-5- Ord. No. 81-80
TABLE A
BASIC THRESHOLD ACCELERATION VALUES FOR ACCEPTABLE VIBRATION ENVIRONMENTS
Daytime is 7 am to 10 pm. Nighttime is 10 pm to 7 am.
All Values are Meters/Sec2
Continuous or Impulsive
Time Intermittent rms Excitation Peak
Type of Place of Day Acceleration Acceleration
Where Received
Hospital Operating Day .0036 .005 Rooms and Other
Such Critical Areas Night .0036 .005
Residential Day .072 .1
(including resi- --
dential SAD) ~ ~--
Night .005 .01
Commercial (including Anytime : 14 .2
non-residential SAD
only)
Industrial and Anytime .28 .4
Other Use ~-~
t = duration seconds of vibration; for durations greater than
100 sec, use t as 100 sec.
N = the number of discrete shock excitations that are one sec or
less in duration. For more than 100 excitations, use N=100.
(12) Stationary non-emergency signalling devices. Sounding or per-
mitting the sounding of any signal from any stationary bell,
chime, siren, whistle, or similar device intended primarily for
non-emergency purposes, from any place, for more than 10 seconds
in any hourly period. Devices used in conjunction with pla~es of
religious worship shall be exempt from the operation of thiS
provision.
(13) Emergency, signalling devices.
(a) The intentional sounding or permitting the sounding outdoors
of any fire, burglar, or civil defense alarm, siren, whistle
or similar stationary emergency signalling devices, except
for emergency purposes or for testing, as provided in Sub-
section (b) hereof.
(b) (i) Testing of a stationary emergency signalling device
shall occur at the same time of day each time such a
test is performed, but not before 7:00 A.M. or after
7:00 P.M. Any such testing shall use only the minimum
cycle test time. In no case shall such test time
exceed 60 seconds.
-6- Ord. No. 81-80
(ii) Testing of the complete emergency signalling system,
including the functioning of the signalling device and
the personnel response to the signalling device, shall
not occur more than once in each calendar month. Such
testing shall not occur before 7:00 A.M. or after 7:00
P.M. The time limit specified in Subsection (b)(i),
above, shall not apply to such complete system testing.
(c) The sounding or permitting the sounding of any exterior
burglar or fire alarm shall comply with the provisions of
Chapter 31 of the Code of Ordinances.
(14) Motor vehicles operating on a public right-of-way. Motor vehi-
cles on a public right-of-way are regulated as set forth in the
Florida Motor Vehicle Noise Prevention and Control Act of 1974,
as set forth in Florida Statutes Section 316.272 and 316.293, as
currently exists or as may hereafter be amended.
(15) Air conditioning or air-handling equipment. Operating or per-
mitting the operation of any residential air conditioning or
air-handling equipment (but excluding cooling towers) in suCh a
manner as to exceed any of the following sound levels in resi-
dential areas when measured as specified in the Code of Recom-
mended Practices:
Measurement location decibels dB(A)
Any point 6n neighboring
property line 60
Center of neighboring patio 55
Outside the neighboring living
area nearest the equipment lo- 55
cation.
(16) Domestic power tools. Operating or permitting the operation of
any mechanically powered saw, drill, sander, router, grinder,
lawn or garden tool, or similar device used in residential areas
which violates the provisions of Section 16-36, except that this
· Subsection shall not apply to the operation of common lawn and
garden equipment between the hours of 7:00 A.M. and 8:00 P.M.
(17) Tampering. The removal or rendering inoperative by any person
other than for purposes of maintenance, repair, or replacement,
of any noise control device or element of design of any product
having such devices.
(18) Noise sensitive zones.
(a) Creating or causing the creation of any sound within any
noise sensitive zone designated pursuant to this ordinance,
so as to disrupt the activities normally conducted within
the zone, or at any time which violates the provisions of
Section 16-36 with regard to receiving land use in all resi-
dential districts, including residential only SAD Districts,
provided that conspicuous signs are displayed indicating the
presence of the zone; or,
(b) Creating or causing the creation of any sound within a noise
sensitive zone designated pursuant to this ordinance, con-
taining a hospital, nursing home, or similar activity so as
to interfere with the functions of such activity or disturb
the patients in the activity, or at any time which violates
-7- Ord. No. 81-80
the provisions of Section 16-36 with regard to receiving
land use in all residential districts, including residential
only SAD districts, provided that conspicuous signs are
displayed indicating the presence of the zone.
(C) Emergency exception.
(a) The provisions of this ordinance shall not apply to:
(1) The emission of sound for the purpose of alerting persons to
the existence of an emergency; or,
(2) The emission of sound in the performance of emergency work;.
or,
(3) The emission of sound in the performance, of an activity for
which pursuant to this Subsection, the City Manager has
expressly given a temporary, emergency exception from this
Article when time would not permit the obtaining of a special
variance pursuant to Subsection 16-36(D) below.
(D) Special Variances.
(a) The Board of Adjustment of the City of Delray Beach shall have
the authority, consistent with this section, to grant special
variances which may be'requested pursuant to Section 16-35(D).
(b) Any person seeking a special variance pursuant to this section
shall file an application with the Board of Adjustment. The
filing fee for such application shall be $25.00. The application
shall contain information which demonstrates that bringing the
source of sound or activity for which the special variance is
sought into compliance With this order would constitute an un-
reasonable hardship on the applicant, on the community, or on
other persons. Notice of an application for a special variance
shall be published in a newspaper of general circulation in the
City of Delray Beach at least seven (7) days prior to its con-
sideration by the Board of Adjustment. Any individual who claims
to be adversely affected by allowance of the special variance may
file a statement with the Board of Adjustment containing any
information to support his claim. If the Boa.rd of Adjustment
finds that a sufficient controversy exists regarding the appli-
cation, a public hearing may be held.
(c) In determining whether to grant or deny' the application, the
Board of Adjustment shall balance the hardship to the applicant,
the community, and other persons of not granting the special
variance against the adverse impact on the health, safety, and
welfare of persons affected, the adverse impact on property
affected, and any other adverse impacts of granting the special
variance. Applicants for special variances and persons con-
testing special variances may be required to submit any infor-
mation the Board of Adjustment may reasonable require.
(d) Special variances shall be granted by notice to the applicant
containing all necessary conditions, including a time limit on
the permitted activity. A special variance shall not become
effective until all conditions are agreed to by the applicant.
Non-compliance with any condition of the special variance shall
terminate it and subject the person holding it to those provi-
sions of this ordinance regulating the source of sound or acti-
vity for which the special variance was granted.
(e) Application for extension of time limit specified in special
variances or for modification of other substantial' conditions
shall be treated like applications for initial special variances
under Subsection (b) above.
-8- Ord. No. 81-80
(E) Appeals.
ApPeals of an adverse decision of the Board of AdjuStment shall
be made in accordance with appeals from the Board of Adjustment
pursuant to Section 30-25(I) of the Code of Ordinances of the
City of Delray Beach, Florida.
Sec. 16-36. Sound levels by receiving land use.
(A) Maximum permissable sound levels by receiving land use.
No person shall operate or cause to be operated a source of sound
as defined in Section 16-35, in such a manner as to create a
sound level which exceeds the limits set forth for the receiving
land use category in Subsections (a), (b) and (c), below, when
measured on or within the property boundary of the receiving land
use and in the manner specified in the Code~of Recommended Prac-
tices, which is hereby incorporated herein by reference.
(a) Sound levels by receiving land use.
Receiving land use Time L:~ Sound level limit, decibel
~v Exterior Interior
R-iAAA 7 A.M. through 10 P.M. 60 45
'R-1AAA-B 10 P.M. through 7 A.M. 55 45
R-1AA
R-1AA-B
R-lA
R-1A-B
RM-6
RM-10
RM-15
PRD-4
PRD-7
PRD-10
SAD (residential only)
Receiving land use Time L=~ Sound level limit, decibel
~v Exterior Interior
NC At all times 65 45
CC
SC
CBD
LC .
SAD (non-residential only)
Receiving land use Time L59 Sound level limit, decibel
Exterior Interior
LI At all times 75 45
MI
(b) The maximum sound levels shall not exceed the L50 limits stated
above by more than 15. dB.
(c) Correction for character of sound.
(i) For any source of sound which emits a pure tone or an impul-
sive sound, the sound level limit set forth in Section
16-36(A)(b) above shall be reduced by five dB.
-9- Ord. No. 81-80
(d) Exemptions. The provisions of this Section shall not apply to:
(i) Activities covered by the following: aircraft and airport
operations,
(ii) The unamplified human voice;
(iii) Interstate railway locomotives and cars;
(iv) Warning Devices required on certain vehicles by federal laws
or regulations.
Sec. 16-'37. Enforcement.
(A) Penalties.
(a) Any person who violates any provision of this ordinance shall be
fined for each offense not more than 500 dollars.
(b) Any person who willfully or knowingly violates any provision of
this ordinance shall be fined for each offense a sum of not less
than 50 dollars and not more than 500 dollars.
(c) Each day a violation of any provision of this ordinance shall
constitute a separate offense.
(B) Abatement orders.
(a) Except as provided, for in Subsection (b) below, in lieu of is- . suing a notice of violation as provided'for in Section 16-38(C)
below, the City official responsible for enforcement of any
provision of this ordinance may issue an order requiring abate-
ment'of any source of sound or vibration alleged to be in vio-
lation of this ordinance within a reasonable time period.
(b) An abatement order shall not be issued: (1) For any violation governed by Section 16-37(A)(b) above or
(2) When the City has reason to believe that there will not be
compliance with the abatement order.
(C) Notice of violation.
Except where a person is acting in good faith to comply with an
abatement order issued pursuant to Section 16-37(B)(a) above,
violation of any provision shall be cause for a notice of vio-
lation to be issued by the City of Delray Beach.
(D) Citizens suits.
Nothing in this Article shall be construed as prohibiting any
person from commencing a civil action on his own behalf against
any person who is alleged to be in violation of any' provision of
this ordinance, nor shall this ordinance be construed to impair
any other common law or statuatory causes of action, or legal
remedies therefrom, of any person for injury or damage arising
from any violation of this ordinance or from other law.
Section 2. That should any section or provision of this ordinance or
any portion thereof, any paragraph, sentence, or word be declared by a
Court of competent jurisdiction to be invalid, such decision shall not
affect the validity of the remainder hereof as a whole or part thereof
other than the part declared to be invalid.
Section 3. That all ordinances or parts of ordinances in conflict
herewith be and the same are hereby repealed.
-10- Ord. No. 81-80
Section 4. That this ordinance shall become effective immediately
upon passage on second and final reading.
PASSED AND ADOPTED in regular session on second and final reading
on this the 16th day of December , 1980.
MAYOR
ATTEST: LEON M. WEEKES
f
City Clerk
First Reading December 2, 1980
SeCond R~ading December 16. 1980
i -11- Ord. No. 81-80
1
CODE OF RECOMMENDED PRACTICES
I. GENERAL
1.1 PURPOSE. This Code of Recommended Practices establishes u~i-
form guidelines for measuring and recording noise levels for the
enforcement of the Noise Control Ordinance of the City of Delray
Beach, Florida (Chapter 16, Article II) whenever a complaint con-
cerning a possible violation of such Ordinance is received by the
City of Delray Beach.
1.2 STANDARDS. This Code of Recommended Practices should be used
in conjunction with the following standards and recommended prac-
tices:
(1) Acoustical Terminology, American National Standards
Institute Incorporated (ANSI) S1.1-1960.
(2) Specification for General - Purpose Sound Level Meters,
ANSI S1.4-1971.
(3) Preferred Frequencies and Band Numbers for Acoustical
Measurements, ANSI Sl.6-1967.
(4) Method for Calibration of Microphones, ANSI S1.10-1966.
(5) Specification for Octave, Half-Octave and Third Octave
Band Filter Sets, ~SI S1.11-1966.
(6) Specifications for Laboratory Standard Microphones,
ANSI S1.12-~967.
(7) Preferred Reference Quantities for Acoustical Levels,
ANSI S1.8-1969.
(8) Recommended Practice Qualifying A Sound Data Acquisi-
tion System, Society of Automotive Engineers, Incorporated
J184.
(9) Standard Method for the Measurement of Sound Pressure
Levels, ANSI S1.13-1971.
1.3 DEFINITIONS.. Unless otherwise defined herein this Code or
within the Noise Control Ordinance, all terminology shall be in
conformance with applicable publication of the American National
Standards Institute, Incorporated (ANSI) or its successor body.
II. INSTRUMENTATION
2.1 REQUIREMENTS. Instrumentation used in making sound level
measurements shall meet the following requirements:.
(1) Sound Level Meter. Sound level meters shall be of at
least Type Two meeting ANSI S1.4-1971 requirements. Alter-
nately, a microphone or sound level meter may be used with a
magnetic tape recorder and/or graphic level recorder or
indicating meter, providing the system meets at least Typ
Two ANSI requirements. For measurements requiring octave
band analysis, the equipment will additionally meet ANSI
S1.11-1966.
(2) Sound Level Calibrator. The entire sound measurement
system shall be calibrated with an acoustic calibrator
recommended by the manufacturer and according to the manu-
facturer's recommended procedures.
(3) Windscreen. An open-cell, foam windscreen recommended
by the manufacturer of the sound level meter shall be used.
2.2 CALIBRATION. The instruments used for acoustical measurements
shall be serviced in accordance with the manufacturer's instruc-
tions. Before and after a series of measurements, the instrumenta-
tion shall be calibrated acoustically according to the manufacturer's
instructions and at intervals not exceeding two hours when the
instrument is used longer than a two hour period.
2.3 METER OPERATION. Unles~ expressed otherwise in this Code, the
sound level meter shall be operated in accordance with instrument
manufacturer's instruction and as follows:
(1) Microphone Location. The microphone shall be located
at a height of four feet above the ground level. All micro-
phone .positions shall be described in the recording of all
data.
(2) Microphone Orientation. The microphone shall be ori-
ented in relation to the source of the sound in accordance
with instrument manufacturer's instructions. Where the
instruction manual is vague or does not include adequate
information, a specific recommendation shall be obtained
from the manufacturer.
(3) Meter Setting. The meter shall be set for the
A-weighted network and fast response.
III. PERSONNEL
3.1 PERSONNEL. Persons selected to conduct sound measurement tests
shall have received training in the techniques of sound measurement
and the the operation of sound measurement instruments.
3.2 TECHNICIAN LOCATION. The technician making direct readings of
the meter shall be positioned in relation to the microphone in
accordance with the instrument manufacturer's instructions. Where
the instruction manual is vague or does not include adequate infor-
mation, a specific recommendation shall be obtained from the manu-
facturer.
3.3 BYSTANDER LOCATION. During sound measurements, bystanders
shall not be within~ 10 feet of the microphone or. noise source,
except for a witness or trainee, who may be positioned behind the
technician on a line with the technicial and the microphone.
IV. MEASUREMENT PROCEDURES
4.1 The following procedure shall be used to determine if a vio-
lation exists pursuant to Section 16-36 (SOUND LEVELS BY RECEIVING
LAND USE) of the Noise Control Ordinance:
(1) Sound Level Meter Location.
(a) The sound level meter shall be located on'adjacent
boundary closest to the noise source or on a lot from
which the complaint arises, unless otherwise specified
in the Noise Control Ordinance.
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(b) If a complaint arises from a multi-story struc-
ture, the height of the sound level meter shall be
adjusted so that it is on a direct line between the
noise source and noise receiver.
(c) The microphone shall be at least three feet from
any adjacent structures.
(2) Exceedance of L50 Sound Level
(a) Every ten seconds read the level from the sound
level meter. Make a total of 25 readings.
(b) Note whether the level is above or below the
specified level for the land use in question for each
reading.
(c) Determine number of readings above and the number
of readings below the specified level.
(d) The specified level is exceeded if the number of
readings above the specified level is greater than the
number of readings below it.
(e) When the nature of the conditions are such that
additional investigation is judged to be required, use
the procedure in (3) below to record the sound levels.
The L50 can be estimated from that data.
(3) Sound level exceeded 10% and 50% of the time period.
(a) Every 10 seconds read the level from the sound
level meter.
(b) Record this level on the data sheet (Figure 1) as
a check mark at the appropriate level.
(c) After 50 samples, test by the confidence criterion
discussed below. If the samples meet the criterion,
then the measurement is complete. If not, then 50 more
samples must be taken and the confidence test repeated.
If the confidence criterion is still not met, addition-
al groups of 50 samples must be completed until the
confidence criterion is met.
(d) Confidence Criterion (i) Counting down from the
top of the data sheet (and from left to right
within each level), circle the "test samples"
· shown in Table 1. For instance, after 50 samples
have been taken, then the first, the fifth and the
10th samples from the top are circled. (See
Figure 1, Example 1.)
(ii) If these three test samples fall into three
contiguous levels, then the measurement is com-
plete. Otherwise, another group of samples must
be taken and tested again. (Sometimes the test
samples will be even more closely packed, falling
into only one or two contiguous levels. IQ these
cases~ the criterion i~ also met.
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(iii) If 100 or more samples have been taken,
skewing is allowed. The two outer test samples
(the error limits) can be shifted by one sample
(not one level) both in the same direction. (See
Figure 1, Example 2.) This sometimes provides the
necessary accuracy without requiring further
sampling. However, if the criterion is still not
met after skewing, then 50 more samples must be
taken and tested.
(e)' Once the confidence criterion has been met, the
level exceeded 10 percent of the measurement period
(the second sample circled), has been determined with
95% confidence to fall between the upper and lower
limit samples. The level exceeded 50% of the time is
the sample determined by counting half of the samples
beginning with tke top or highest one.
(4) Maximum Sound Level.
(a) As noise source radiates sound, read the maximum
deflection of the needle of the sound level meter.
(b) If possible, determine and record the minimum
sound level during the period of observation.
4-.2 The following procedure shall be used to determine if a viola-
tion exists pursuant to SECTION 16-36 (MULTI-FAMILY DWELLINGS) of
the Noise Control Ordinance:
(1) The microphone of the sound level meter shall be set at
any point four feet from wall, ceiling or floor that is
radiating noise and at least three feet from any adjacent
structures.
(2) Determine if sound is pure tone.
(3) Use appropriate measurement procedure described in
Section 4.1(3) or 4.1(4).
(4) If possible, repeat procedure for different microphone
locations.
4.3 The following procedure shall be used to determine if a viola-
tion exists pursuant to SECTION 16-35(15) (AIR CONDITIONING OR AIR-
HANDLING EQUIPMENT) of the Noise Control Ordinance:
(1) Sound level measurements which may be required shall be
measured on the A-weighting network of a sound level meter
using the fast meter response. (When meter reading fluctuates,
use average reading.)
(2) Sound measurements shall be made as follows:
(a) Measurements at the property line or center of
patio shall be taken with the microphone at five (5)
feet above grade level and no closer than three (3)
feet from any wall.
(b) Measurement outside the window of a living area of
adjacent property nearest the equipment location shall
be taken with the microphone not more than three (3)
feet from the window opening but at least three (3)
feet from any other ~u~f~ce.
(3) A minimum of three (3) readings shall be taken at two (2)
minute intervals. The sound level shall be the average of
these readings.
(4) Should the sound level exceed the sound level of Sec-
tion 16-36(15) as measured above with the equipment in
operation, additional measurements shall be made with the
equipment not operating in order to determine its contribu-
tion to the sound level. If the difference in levels ex-
ceeds 4 dB with the equipment operating and not operating,
the equipment shall be considered in violation of the ordi-
nance and shall be modified or controlled so that the
difference does not exceed 4 dB or the measurement complies
with Section 6.2.16.
4.4 Re: Section 16-35(14) (MOTOR VEHICLE MAXIMUM SOUND LEVELS).
Officials trained in the enforcement of the Florida Motor Vehicle
Noise Prevention and Control Act of 1974, Chapter 74-110, Laws of
Florida, shall follow the procedures described in Department of
Environmental Regulation Rule Chapter 17-18, Vehicle Sound
Measurement, Part I,~Highway Vehicle Test Procedure.
V. REPORTING MEASUREMENTS ~
5.1 INFORMATION. The following information shall be obtained
and reported for each sound measurement period:
(1) Dimensioned sketch or photograph of the test area showing
location of sound source(s) and receiver(s).
(2) Note any possible reflecting objects within test area.
(3) Physical and topographical description of the ground
surface.
(4) Meteorological conditions, including temperature, relative
humidity, wind direction and speed.
(5) Equipment and settings used for sound measurement.
(6) Date, time and length of measurement period.
(7) Measured sound level(s).
(8) Background sound level.