DRAFT
COMMUNITY NOISF ORDINANCE WORKBOOK
B Y
ROBERT C. CHANAUD and ROBFRT A, SIMMONS
FPA Acoustics Consultant Supervisor
Noise Control Program
AIR AND HAZARDOUS MATERIALS DIVISION
REGION VIII
U.S. ENVIRONMENTAL PROTECTION AGENCY
I860 Lincoln Street
Denver, Colorado 80?07
REVISED
August .1975
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iJ- z<^0
TABLE OF CONTENTS
CHAPTER 1: INTRODUCTION 1-1
CHAPTER 2: PROCEDURES FOR DEVELOPING A NOISE ORDINANCE
PHASE 1 ASSIGNMENT OF KEY OFFICIAL
Step 1 Form Citizen Group, Complain to 2-1
Authorities -
Step 2 Meeting with Decision Makers - - 2-2
Step 3 KEY OFFICIAL ASSIGNED, Official Study
Group Formed - 2-4
PHASE II STUDY OF THE PROBLEM; RECOMMENDATIONS
Step 4 Assemble the people and tools to
Conduct the study 2-6
Step 5 Design and conduct an attitudinal and
noise measurement survey ------- 2-11
Step 6 Assess the problem including future
charges 2-18
Step 7 Develop H&W goals, determine current
and future actions of other governt-
mental agencies, and DEVELOP RECOMMEND-
ATIONS FOR ACTION 2-24
Step 8 Report to decision makers ------- 2-29
PHASE III ORDINANCE DEVELOPMENT
Step 9 Decide on scope of ordinance and 2-31
enforcement methods ----------
Step 10 Develop rough draft ordinance ----- 2-35
Step 11 Review of draft by various parties - - 2-41
Step 12 Revision of draft, cost and manpower - 2-42
Step 13 Study session with City Council - - - - 2-43
Step 14 Noise Demonstration 2-44
Step 15 Formal presentation for first reading - 2-46
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CHAPTER 3: TECHNICAL TERMINOLOGY
REFERENCE List of Definitions and Important Terms - 3-1
Section 3.1 Introduction - - 3-4
3.1.1 Purpose of Chapter - 3-4
3.1.2 Sound vs. Noise --------3-4
3.1.3 Some Characteristics of Sound - 3-5
Section 3.2 Sound Level Meters 3-8
Section 3.3 Sound Pressure - 3-10
3.3.1 Sound Variables 3-10
3.3.2 Units of Sound Pressure - - - - 3-11
Section 3.4 The dB Scale - - - - 3-12
3.4.1 What it is 3-12
3.4.2 Comparison with Linear Scale - - 3-13
3.4.3 Advantages and Disadvantages
of dB Scale - - - 3-13
Section 3.5 Sound Pressure Levels vs. deci Bels - - 3-14
3.5.1 Definition of Sound Pressure
Level 3-14
3.5.2 Addition of Unrelated Sounds - - 3-16
3.5.3 Subtraction of Unrelated Sounds 3-18
Section 3.6 Frequency Weighting of Sound Pressure
Levels 3-18
Section 3.7 Fluctuating Sounds ---------- 3-20
3.7.1 Why Measure Fluctuating Sounds - 3-20
3.7.2 Measuring Fluctuating Sounds - - 3-21
3.7.3 Historgrams ---------- 3-24
3.7.4 Cumlative Distributions - Ln - - 3-25
3.7.5 Energy Equivalent Sound Level
Leg 3-26
3.7.6 Day-Night Aver. Sound Level L^ 3-28
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CHAPTER 4: NOISE EFFECTS ON HEALTH AND WELFARE:
THE REASONS FOR NOISE CONTROL
1. INTRODUCTION 4-2
2. HEARING LOSS 4-11
3. SPEECH INTERFERENCE 4-23
4. SLEEP INTERFERENCE 4-27
5. OTHER PHYSIOLOGICAL EFFECTS 4-36
6. ANNOYANCE - 4-41
7. OTHER PSYCHOLOGICAL EFFECTS 4-45
8. EDUCATIONAL RETARDATION - 4-47
9. PERFORMANCE LOSS - 4-52
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CHAPTER 5: TECHNICAL AND ECONOMIC FEASIBILITY
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CHAPTER 6: THE LEGAL BASES FOR COMMUNITY NOISE CONTROL
I. FEDERAL GOVERNMENT 6-1
II. STATES AND THEIR POLITICAL SUBDIVISIONS 6-5
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CHAPTER 7: ORDINANCE COMPONENTS
ARTICLE I SHORT TITLE 7-12
ARTICLE II DECLARATION OF FINDINGS 7-12
ARTICLE III DEFINITIONS AND STANDARDS 7-13
Section 3.1 Terminology and Standards 7-13
Section 3.2 Definitions 7-14
3.2.1 A-weighted Sound Pressure Level - 7-14
3.2.2 Ambient Noise Level 7-15
3.2.3 Commercial Use District 7-16
3.2.4 Continuous Noise 7-17
3.2.5 Cyclically Varying Noise 7-18
3.2.6 Day-Night Average Noise Level — 7-19
3.2.7 Decibel — — 7-19
3.2.8 Device 7-19
3.2.9 Dynamic Braking Device 7-20
3.2.10 Emergency Work 7-20
3.2.11 Emergency Vehicle 7-21
3.2.12 Fluctuating Noise 7-21
3.2.13 Impulsive Noise 7-22
3.2.14 Industrial Use District 7-23
3.2.15 Motor Vehicle 7-23
3.2.16 Muffler 7-24
3.2.17 Ninetieth Percentile Noise Level -- 7-25
3.2.18 Noise 7-26
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7-2
3.2.19 Noise Disturbance 7-26
3.2.20 Person - 7-27
3.2.21 Plainly Audible Noise 7-27
3.2.22 Powered Model Vehicles 7-28
3.2.23 Property Boundary 7-28
3.2.24 Public Right-of-way 7-29
3.2.25 Public Space 7-29
3.2.26 Pure Tone - 7-29
3.2.27 Residential Use District 7-30
3.2.28 RMS Sound Pressure 7-31
3.2.29 Sound 7-31
3.2.30 Sound Level Meter 7-31
3.2.31 Sound Pressure 7-32
3.2.32 Sound Pressure Level 7-32
3.2.33 Sound Power 7-34
3.2.34 Sound Power Level - 7-34
3.2.35 Stationary Noise Source - —- 7-35
3.2.36 Steady Noise 7-35
3.2.37 Tenth Percentile Noise Level 7-36
3.2.38 Vibration 7-36a
3.2.39 Vibration Perception Threshold 7-37
3.2.40 Watercraft - 7-38
3.2.41 Weekday 7-38
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7-3
ARTICLE IV AGENCIES 7-39
Section 4.1 Environmental Protection Office 7-39
Section 4.2 Departmental Actions - 7-39
Section 4.3 Departmental Cooperation — 7-39
Section 4.4 Compliance with Other Laws 7-40
Section 4.5 Project Approval 7-41
Section 4.6 Right of Review 7-41
Section 4.7 Contracts 7-42
Section 4.8 Low Noise Emission Products 7-43
ARTICLE V AUTHORITY AND DUTIES - — - 7-45
Section 5.1 Powers of Environmental Protection Officer 7-45
5.1.1 Studies 7-45
5.1.2 Education 7-45
5.1.3 Coordination and Cooperation 7-47
5.1.4 Project Reviews 7-48
5.1.5 Inspections 7-48
5.1.6 Records 7-49
5.1.7 Measurements 7-49
Section 5.2 Duties of Environmental Protection Office 7-50
5.2.1 Measurement Standards 7-50
5.2.2 Truck Routes 7-50
5.2.3 Enforcement Procedures 7-50
5.2.4 Enforcement of Federal Regulations 7-50
5.2.5 Long Term Noise Reduction Goals 7-51
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7-4
ARTICLE VI NOISES PROHIBITED 7-52
Section 6.1 General Prohibitions 7-52
Section 6.2 Specific Prohibitions 7-53
6.2.1 Horns and Signalling Devices 7-54
6.2.2 Radios, Television Sets and
Similar Devices 7-55
6.2.3 Exterior Loudspeakers 7-57
6.2.4 Street Sales 7-61
6.2.5 Animals 7-62
6.2.6 Loading Operations 7-65
6.2.7 Construction Noise 7-66
6.2.8 Vehicle Repairs or Testing — 7-70
6.2.9 Ai rcraft Operations - - 7-70
6.2.10 Places of Public Entertainment 7-72
6.2.11 Impulsive Sources 7-78
6.2.12 Motor Vehicle Racing Events 7-79
6.2.13 Powered Model Vehicles 7-80
6.2.14 Dynamic Braking Devices 7-82
6.2.15 Refuse Compacting Vehicles 7-83
6.2.16 Standing Motor Vehicles 7-85
6.2.17 Vibration 7-86
6.2.18 Bells and Alarms 7-88
6.2.19 Fixed Sirens, Whistles, and Horns — 7-91
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7-5
6.2.20 Watercraft 7-92
6.2.21 Quiet Zones 7-94
6.2.22 Domestic Power Equipment 7-95
ARTICLE VII EXCEPTIONS AND PERMITS 7-98
Section 7.1 Emergency Exception 7-98
Section 7.2 Permit Issuance 7-100
Section 7.3 Exemptions for Time to Comply 7-101
ARTICLE VIII NOISE LEVELS BY LAND USE 7-104
Section 8.1 Maximum Permissible Sound
Pressure Levels 7-104
Section 8.2 Duration Correction - 7-126
Section 8.3 Correction for Character of Sound 7-131
ARTICLE IX MOTOR VEHICLE SOUND LEVELS 7-133
Section 9.1 Maximum Permissible Sounrl I.pvpIs
of Motor Vehicles 7-133
9.2.1 Measurement Distance 7-153
ARTICLE X RIIILMNfi NMSF LFVEI.S 7-154
ARTICLE XI LAND USE 7-155
ALTERNATIVE 1
Section 11.1 Noise Impacted Land Use 7-156
Section 11.2 Commercial or Industrial Land Use 7-160
Section 11.3 Road Construction 7-161
Section 11.4 Road Building 7-161
Section 11.5 Zoning Changes - - 7-162
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ALTERNATIVE 2
Section 11.1 Identification of High Noise Areas 7-165
Section 11.2 Site Study Requirement 7-165
Section 11.3 Use Restrictions in High Noise Areas 7-166
Section 11.4 Field Testing 7-166
Section 11.5 Equivalent Measurement Systems 7-167
ARTICLE XII ADDITIONAL PROVISIONS 7-168
Section 12.1 Penalties 7-168
12.2
12.3
12.4 Contracts - 7-172
12.5 Low Noise Emission Products 7-174
12.6 Method of Enforcement 7-175
ARTICLE XIII SEVERABILITY 7-177
REFERENCES 7-178
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CHAPTER 1
INTRODUCTION
Intended Readership: City Council members, decision
makers, or other individuals
with potential interest in
initiating a noise control
ordinance and corresponding
program.
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1-1
To take some liberties with the social commentary of Will
Rogers, we night say that noise control is a little like bunions.
Knowing that nearly everybody has them doesn't make them hurt
any the less. So it is that knowing 16 million people 1n the
United States have a hearing loss in which noise may have played
a part, 26 million people's lives are less enjoyable because
of the impact of aircraft noise, and over 100 million people
are annoyed by traffic noise from trucks, buses, trains, high-
performance cars, etc., doesn't help at all when it is your
neighbor's son's new motorcycle tearing up the vacant lot next
door that's keeping you from sleeping on a Saturday morning.
Noise annoyance is an intensely personal thing, and des-
pite the fact that one man's music may be his neighbor's noise,
annoyance is only one of several undesirable effects that noise
may have on our health and welfare, or the quality of our lives.
Others, which are often overlooked as one considers the just-
ification for controlling noise are its effects on hearing
(acuity), speech communication, sleep, education and learning,
job performance, stress and our recovery from illness, property
values, and the quality and quantity of our recreational ex-
perience.
Noise drives people to do strange and tragic things. The
press has duly noted the death of a chila slain while playihy
in the street by an elderly man who couldn't sleep (^ew Yor|< p0st,
April 16, 1968),
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the man who responded to his neighbor's
momentarily unattended motorcycle by ripping out every exposed
wire, and the intrepid forest ranger who, in desperation, shot
a snowmobile "dead in its tracks" in Glacier Park recently.
In a misguided attempt to prevent that sort of desperate
behavior, it may be noted that nearly every community of any
size in the United States has a noise ordinance of some sort.
In fact, whenever anyone suggests the need for some legal
means to better control comnunity noise sources, someone else
is sure to point to the existing one, and insist that "a
little enforcement" is all that's really needed.
But the plain truth of the matter is, that the typical nuisance
noise ordinance found on the books of most communities simply
does not work. With such ordinances, no one can remember
when the last conviction was obtained on a noise charge, and
arresting officers, defendants, and the courts can seldom
agree on what constitutes the "unusually loud" or "unnecessarily
noisy" events that the nuisance ordinance prohibits. Convictions
are thus rare, and indeed, even some of those have been success-
fully appealed on the grounds that the law is unconstitutionally
vague.
Where then, does a community begin when the irritation
with environmental noise finally reacnes the point that "some-
thing must be done?? Occasionally, a particularly responsive
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municipal government will take the first steps. But more
often, it is first of all, individual citizens, discovering
a common source of frustration, shared with others, perhaps
from a nearby airport, a new freeway, a large construction
project, or simply from motorcycles, who finally press the
quest for quiet into the laps of their government.
The fact that you are reading this document suggests
that for whatever the reasons, you have at least a tentative
interest in the problem of community noise, and either will-
ingly (or perhaps unwillingly), considering some potential
solutions to that problem.
At this point, you and many other readers may begin to
question the feasibility of all this. You may be convinced of
the need, there may be support in the community, but you are
just not sure the job can be accomplished in such a way as to
get the desired results in your community.
All we can say is that several other communities have
come to just that point, and have developed quite successful
programs for noise control. The results of much of that
process have formed the basis for this workbook.
This workbook, then, is designed to provide anyone, who
has an interest in controlling community noise, with the shared
experiences of other communities and those who have worked
closely with them, as they have wrestled the inevitable problems
to remarkably satisfactory conclusions. The authors have noted
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the striking similarity in those problems, and this book
is an attempt to deal with their common aspects in workbook
form. Every attempt has been made to make it useful and
practical, as technically and legally accurate as possible,
and sensitive to as many of the options that are open to
communities as we haVe been able to identify to date.
Because many of these areas are in a state of constant
change and development, particularly the legal precedents
and federal preemption, the workbook format was chosen to
facilitate easy revision with updated material to be made
available as needed. The various chapters of the workbook
are collectively designed to demonstrate thtit:
a. It has been used successfully by other communi-
ties to establish noise control programs on the basis of this
accumulated experience.
b. It can be used by your community to write an
effective ordinance which will remedy the inadequacies of the
old, nuisance ordinances (Chapters 3,4,5,6, and 7).
c. It is economically feasible to control noise
NOW (Chapter 5). Noise control has been achieved in most of
the successful programs with negligible economic impact on noisemakers,
and at a per-capita cost of 10$ - 75
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noise control provisions (Chapters 3,5 and 7). The assumption
that noise is too technical and'complIcated to deal with 1s
false. Many coiranunities are achieving good results with a
minimum investment in technical equipment and with only brief
personnel training programs.
e. It 1s a health and welfare problem that needs
solution (Chapter 4). It is legqlly workable (Chapter 6) and
quite consistent with the thrust of the U. S. Noise Control
Act of 1972, which states that the "primary responsibility for
control of noise rests with state and local governments" and
that 'it is the policy of the United States to promote an
environment for all Americans free from noise that jeopardizes
their health or welfare". The Environmental Protection Agency
is authorized to "provide technical assistance to state and
local governments to facilitate their development and enforce-
ment of ambient noise standards, including but not limited to:
a. advice on training of noise control personnel
and on the selection and operation of noise-abatement equipment; and
b. preparation of model state or local legislation for
noise control.
The Regional Administrator for EPA Region VIII has estab-
lished a noise control program which began helping interested
communities establish their own noise control programs as early
as 1971.
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If you find that your community is-.seriously considering
a noise control program, there are several steps that yoi[
can take, right at this point, that will help immeasurably in
getting your community's noise control efforts off to a good
start. The most important of these is to:
1. Assign the "right" key official to lead the effort.
Who this person is, and whether he is an interested citizen,
an employee of the city planning or health departments, or
perhaps a city councilman, and whether he is elected, appointed,
drafted, or "shanghaied" is less important than the fact that
he is willing to do the job. That person should in turn, as is
suggested in the proceedures of Chapter 2;
2. Determine the need for an ordinance. Don't be
part of a "bulldozing" effort to create a community-wide
ordinance for the purpose of solving a noise problem faced by a
very few people, or one that addresses only one noise source,
such as motorcycles, etc. There are other, more efficient
ways to handle those. Chapter 2 of this workbook provides
specific information for determining the need for a broadly-
based community noise control ordinance. If the need is there,
and the community support is assured, you are justified in
proceeding to the next step.
3. Become knowledgeable about noise. Some of the
more technical aspects of noise and sound measurement are
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sufficiently complicated that many people are discouraged
from trying to understand them. This has not prevented many
communities with a lot of Interest and relatively little
expertise 1n acoustics from establishing very effective noise
control programs. This workbook contains sections pertaining
to the health effects of noise and the basics of its measure-
ment which are more than adequate to get the program under way.
4. Develop health and welfare goals. These goals
mast be decided by your own community to accomplish purposes 1t
considers Important. No one else can do it for you, and it
is usually a mistake to "adopt" an ordinance, "as is", from some
otbbr community. If yours 1s a resort community where many
people go to "get away from it all", your noise program goals
are apt to be quite different from a town whose entire economic
health is dependent on industries or processes that are in-
herently noisy.
5. Devise a realistic program for noise control. The
initial step evolves drafting a comprehensive noise control
ordinance which usually includes, among other elements; vehicular
standards, use zone standards, and land use prevention and
maintenance features. Successful examples of community noise
control programs appear to be composed accordingly:
50% Enforcement
40% Education
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5% Administration
5% Aspiration
A second step may be necessary if 1t was not economically
or socially feasible to achieve and maintain your health and
welfare goals with the initial ordinance. Then a step by step
program of ordinance Improvements should be designed which
will achieve your goals at a designated future date.
The initial "key to success" is turned by assigning the
right key official to launch your noise control effort. We
encourage that person to make full use of the Chapter 2 pro-
cedures and other portions of the Community Noise Ordinance
Workbook to assist him with your endeavor.
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CHAPTER 2
PROCEDURES FOR DEVELOPING A NOISE ORDINANCE
This chapter is a guide for using the remainder of the workbook.
It gives detailed chronological steps that should be followed (where
applicable) in order to insure the orderly development of a noise
ordinance. The information has been culled from a
large number of actual ordinance developments. Because the develop-
ment process is largely political, we have addressed primarily those
aspects which are necessary ingredients in any development with
cautions about the various possible political pitfalls that may be
encountered.
We have provided Figures 2-1 to 2-3 as a flow chart to integrate
the various steps given , All steps of this chapter may not be
necessary in cases where few difficulties are encountered, so the
degree of formality of the process is highly flexible.
Intended Readership: Those interested in, or responsible for,
bringing a noise control program into
existence.
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TABLE OF CONTENTS
PHASE I ASSIGNMENT OF A KEY OFFICIAL
Step 1 Form Citizen Group, Complain to Authorities
Step 2 Meeting with Decision Matprs
Step 3 KEY OFFICIAL ASSIGNED, Official. Study Group Formed
PHASE II STUDY OF THE PROBLEM; RECOMMENDATIONS
Step 4 Assemble the people and tools to conduct the study
Step 5 Design and conduct an attitudinal and noise measurement
survey
Step 6 ASSESS THE PROBLEM includino futii^p phanqos
Step 7 Develop H&W goals, determine current and future actions of
other governmental agencies, and DEVELOP RECOMMENDATIONS
FOR ACTION
Step 8 Report to decision makers
PHASE III ORDINANCE DEVELOPMENT
Step 9 Decide on scope of ordinance and enforcement methods
Step 10 OEVFLOP ROKGH ORAFT HPDINANCE
Step 11 Review of draft by various parties
Step 12 Revision of draft, cost and manpower estimates
Step 13 Study session with City Council
Step 14 Noise Demonstration
Step 15 Formal presentation for first reading
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PHASE I: RECOGNITION OF THE PROBLEM
CITIZEN DISSATISFACTION
STEP 1
STEP 2
STEP 3
CITIZEN
COMMITTEE
FORMED
COMPLAINTS TO
MUNICIPAL
AUTHORITIES
MEETING WITH PECIS1QN, MAKER?
STUDY GROUP
FORMED
KEY OFFICIAL
h SSITO
FIGURE 2.1
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PHASE II: KEY OFFICIAL/STUDY GROUP STUDIES PROBLEM
STEP 4
STEP 5
STEP 6
STEP 7
STEP 8
FIGURE 2.2
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PHASE III: ORDINANCE DEVELOPMENT
STEP 9
STEP 10
STEP 11
STEP 12
STEP 13
STEP 14
STEP 15
DECIDE ON SCOPE OF ORDINANCE
AND ENFORCEMENT METHODS
DEVELOP ROUGH DRAFT OF ORDINANCE
REVIEW OF
ROUGH DRAFT
COMMENTS
EXPERTS
CITIZENS
CITY ATTORNEY
OPPOSITION
PROPOSED
ENFORCEMENT
flftrwrv
OTHER AGENCIES
FIGURE 2.3
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PHASE I: ASSIGNMENT OF A KEY OFFICIAL
both
Getting a municipal official assigned to lead/the study and
development of a noise program and ordinance is essential and every
effort to get one is worthwhile.
STEP 1 FORM CITIZEN GROUP, COMPLAIN TO AUTHORITIES
Purpose: To get together citizens concerned about
noise and to find out how much concern there is
about noise in the community by determining
the nature and number of complaints.
Output: A citizen group that can bring pressure
on community leaders for action.
1A FORM UNOFFICIAL CITIZENS GROUP
Notes: 1. Read Chapters 1, 2, 3, and 4 of workbook
for support.
2. Solicit support by phone, advertisements
in papers, or letters to the local editor.
3. Borrow sound level meters to get some
familiarity with equipment. EPA or state
and local agencies may have some.
4. Establish immediately whether there 1s wide-
spread dissatisfaction and thus a strong
support for noise control.
5. Request meeting with municipal officials.
IB COMPLAIN TO AUTHORITIES
Notes: 1. Encourage complaints to authorities among
individuals contacted.
2. Complain to Police Department, as well as
administrative officials. Police may give
support for noise control efforts.
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3. Make a separate list of specific complaints
already made or being made for presentation
purposes.
4. Use Chapter 4 of this workbook to point out
the importance of noise control.
STEP 2 MEETING WITH DECISION MAKERS
Purpose: To get the community decision makers
to at least study the noise problem by
assigning a Key Official to the task
and/or forming a study group.
Output: A commitment to stud.y the Droblem and
to assign an official bv name.
Notes: 1. Meet with appropriate officials to
get support, and then meet with
Cit.y Council.
2. If you think officials will be
present, make a simple noise
demonstration (described in
STEP 14).
3. The presentation should establish that:
a. There is a health and welfare problem
caused by noise
b. Noise ordinances are understandable
and enforceable.
c. It is technically feasible to
reduce noise.
d. There is little economic hardship
on the violator in most cases.
e. There is widespread citizen support
for noise control.
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4. Chapter 1 of this workbook should be
duplicated and given out as background
material and as a basis for comments.
5. Push for the assignment of a Key Official by:
a. Noting that the problem needs to be
studied to determine whether or not
ordinance 1s necessary.
b. Noting that If an ordinance is
appropriate, it should be written
to cover all present and future
noise sources to avoid one that
focuses on a specific group of
violators. Study is necessary.
c. Noting that specific goals for the
protection of health and welfare must
be developed before an ordinance so
that a total program can be devised
rather than an ordinance that 1s
not enforced. Study 1s necessary.
6. At the meeting:
a. Have as much support for your side
as possible.
b. Avoid discussing the enforcement agency
or enforcement methods. Everyone
immediately thinks of the police, but
experience show that they are not the
best lead agency for noise control.
c. Do not concentrate discussion on a
specific class of noise polluters.
d. Let the decision makers decide on
the advisability of an official
citizen study group. in general,
they can be very helpful, but some
community officials report bad
experiences with them.
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e. Consider the makeup of the
listeners, to insure that
there will be some emotional
rapport. Experience has
shown that a negative response
occurs when too many emotional
women confront a business-
oriented male City Council.
STEP 3 KEY OFFICIAL ASSIGNED, STUDY GROUP FORMED
Purpose: To provide guidance to decision makers
on the choice of a Key Official and the
value of an official study group.
Output: A Key Official and/or study group
that is committed to thoroughly studying
the community noise problem.
3A KEY OFFICIAL ASSIGNED
Notes: 1. Choose an official that is not in a
day-to-day crisis position.
2. Choose one who does not already have
a bias and works well with groups,
i.e., listens but also directs
activities toward a common goal.
3. Correnuni ties have found that the
ordinance generation process is
smoother if the Key Official is
not a member of the City Attorney's
staff or the police because of the
demands on their time.
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3B STUDY GROUP FORMED
Notes: 1. Any study group Is best when under
the direction of, or 1n close
liaison with, the Key Official.
2. The group is best if composed of
proponents of the ordinance and
neutral experts in related areas.
Opponents could disrupt the
activities to the point where no
action could be taken. Background
of individuals composing the group
should be in the areas of audlology,
law, engineering, enforcement, as well
as those who have been affected by
noise.
3. The group should organize to
accomplish Phase II
4. It should provide the Key Official
with all material gathered to this
point, including this workbook.
5. It should be organized to relieve
the Key Official of work, but not
to get him to do more.
6. It should volunteer to assist in
any field work necessary.
7. The effort will be materially
assisted if the group can convince
the Key Official (who will be under
time pressure) that an orderly pro-
cedure, such as suggested herein,
will result in an ordinance with few
legal, technical, enforcement and
administrative problems and one that
will be comprehensive enough to suit
the needs of the comnunity. As a
result, the City Council will be
more receptive to the ideas and
the proposed actions.
8. It can read, digest, and synopsIze
the material collected so 1t acts
as an information resource.
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PHASE II: STUDY OF THE PROBLEM; RECOMMENDATIONS
An adequate study will define whether an ordinance is really
needed, and, if it is, the study will provide many of the basic
facts needed to write an appropriate ordinance. These steps are
for the information of the Key Official.
STEP 4 ASSEMBLE THE PEOPLE AND TOOLS TO CONDUCT THE STUDY
Purpose: To collect knowledgeable individuals and
information needed to conduct an adequate
study.
Output: The Key Official should thoroughly
understand the organization necessary to
achieve the passage of an appropriate
ordinance and should have much of the
necessary information to conduct a
community survey.
4A COLLECT INFORMATION
Notes: 1. Readinq Chapter 2 before conrnencina action will
give the Key Official a feel for the kind of
task he has set out to accomplish and will
give him specific guidance on what he needs
to know.
2. There are five areas of information that need
to be collected to adequately write an ordinance:
(1) the terminology needs to be mastered suf-
ficiently to make reasonable presentations and
Chapter 3 gives some detail on that; (2) the
health and welfare basis for the ordinance needs
to be established; and Chapter 4, along with
numerous EPA and other documents referenced,
is provided;
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2-7
(3) the legal basis for the ordinance
and how 1t relates to state and Federal legis-
lation must be addressed and Chapter 6 discusses
the Federal legislation, while state law needs
to be obtained; (4) the possible economic effect
of the ordinance must be addressed and Chapter 5
discusses the subject giving ideas on how to
determine that effect; and (5) the best method
by which the ordinance should be brought into
being must be addressed and this chapter dis-
cusses that subject.
3. Collect other noise ordinances of local com-
munities. Although this information will make
the Key Official feel more comfortable with a
noise ordinance, reading these ordinances and
building a new one from them has many pitfalls.
We have found that many ordinance writers will
choose an ordinance section that 1s most
commonly found in the other ordinances. Noise
control 1s a dynamic activity and most
ordinances are out-of-date, Ineffective,
technically erroneous, and may cover subjects
of no relevance to your community, so copying
can Introduce serious deficiencies in your new
ordinance. Chapter 7 really is a summary and
compilation of nany successful noise ordinances,
which are referenced there, so collecting
ordinances now will assist at the stage when
Chapter 7 needs to be studied.
4. Administrative officials should read Chapters 1
and 2 of this workbook. The Key Official should
read Chapters 1-4 and he should assign to others,
if possible, the task of digesting Chapters 3-5,
which requires specific backgrounds. If there is
is a study group, they can be very helpful in
collecting Information and becoming a knowledgeable
person in one of the areas.
5. There 1s usually strong pressure to draft an
ordinance quickly, so it 1s tempting to study
Chapter 7 of this workbook first and get some-
thing on paper. It should only be scanned to
become
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2-8
familiar with the contents at this point.
Generally, noise control is sufficiently
unfamiliar to the Key Official so that if
he does this too soon, he will be unable
to answer the questions he gets in the
review process. This can be embarrassing
and we recommend that the Chapter 2 process
be followed so that Chapter 7 is studied
in detail in Step 10 when the proper background
is obtained.
6. Material of special importance is referenced
in this workbook and is marked with an
asterisk at the end of each chapter. These
materials should be collected as supplementary
reading.
4B OBTAIN LOCAL EXPERTS
Notes: 1. Local research laboratories or universities may
have an individual who is experienced in acoustics,
vibration, audiology, noise control, or other
closely related discipline. He can be quite
valuable concerning terminology or health and
welfare effects.
2. Local city, county, state, or Federal agencies
may have personnel with some knowledge of noise
control and who may be willing to assist, either
officially or unofficially. A partial listing
of potential agencies is given below:
Federal
Federal Aviation Administration, Regional Office
Environmental Protection Agency, Regional Office
(The EPA is required to provide such
assistance based on the Noise Control
Act of 1972).
Dept. of Housing & Urban Development Regional Office
Federal Highway Administration, Regional Office
Occupational Safety & Health Administration,
Regional Office
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2-9
State
Health Department
Highway Department
Environmental Protection Agency (if any)
City and Counties
Communities with noise ordinances
City/County Health Departments
3. Local acoustical consulting firms may have
the expertise and equipment you need and
may be willing to assist without charge.
4. Other officials or quasi-officials in your
own community can be very helpful, especially
during the latter phases of ordinance develop-
ment, and of your activities. It may be wise
to notify them, some are:
Animal Control
Police
Fire
Ambulance
Planning Dept.
Building Inspectors
Maintenance Dept.
Parks or Recreation Dept.
5. Professional organizations may be contacted for
possible expert help. The Acoustical Societjr of
America (whose address is c/o American Institute
of Physics, 335 E. 45th St., New York, N. Y. 10017)
has a group of Regional Coordinators as part of
their Coordinating Committee on Environmental
Acoustics. They are scattered around the United
States, and their names and addresses may be ob-
tained at the address above. The Institute of
Noise Control Engineering has a number of en-
vironmental noise experts. Their names and
addresses may be obtained by writing INCE,
P.O. Box 3206, Arlington Branch, Poughkeepsie,
N.Y. 12603.
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2-10
6. Later on you may wish to use library
resources for detailed information
on a specific topic. Aside from
books, there are the following journals:
a. Journal of the Acoustical Society of America
b. Sound and Vibration magazine
c. Noise Control Engineering
d. Speech and Hearing
e. Proceedings of N0ISEXP0 (year)
f. Proceedings of Inter-Noise (year)
4C RECEIVE AND DOCUMENT COMPLAINTS
Notes: 1. Establish a place in the city to receive
complaints. Normally the Police Department
receives them, but if they are transferred
to the Key Official, they can be very
helpful. Advertising this fact through the
local newspaper will elicit many more com-
plaints than expected. This increase occurs
because most people think that little can
be done about noise and so normally do not
complain. Hope changes the picture.
2. Receive the complaints in writing or have a
secretary complete a form similar to the
questionnaire discussed later. Do not get
involved with lengthy discussions with
complainants nor attempt to respond to them
or you will have little time left to work on
the ordinance. See Chapter 4, Section 6 for
the information related to annoyance. You
need to establish the noise sources and their
affect on the complainant for use in Step 6.
Other state and county agencies may have in-
formation on complaints, as well as other
municipal departments. A sample complaint
form is shown in Figure 2-4.
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NOISE COMPLAINTS, INFORMATION REQUESTS, & TECHNICAL ASSISTANCE REQUESTS
tructions: Please .jot down LI 10 following information about' individuals registering a
complaint or reinjecting information. Under nature of complaint and
information requested, more than one space may be checked.
NAME:
ADDRESS:
ZIP CODE:
OCCUPATION:
DATE:
PHONE:
SEX:
Mature of Complaint:
I. GENERAL TRAFFIC
Ambulances
Buses
Cars
Fire Trucks _
II. AIRCRAFT
;i. Sonic boom
Garbage Trucks
Mini-Dikes
Police Cars
Motorcycles
Sport Cars
General Road
Trucks
Road construction
Highway noise
d. Groun.d runup
GENERAL ZONING
Bldg. mechanical equipment
Power lawnmowers
IV. MISCELLANEOUS
Railroads
Other
b. Flyover
c.
Takeoff
Landi ng
Hi-Fi equipment
Building construction
Dogs
Chain Saws
Home appliances
Remarks:
FIGURE 2-4
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2-11
4D INFORMAL SURVEY
Notes: Tour the community with a zoning map and a
sound level meter, if at all possible. You
can probably borrow such equipment from other
communities, your state government (Highway Dept.)
or your Regional Office of the U.S. EPA.
By taking notes of the levels and locations
relative to residential areas, the official
can get a good subjective feel of the noise
sources and how objectionable they are. Such
an informal survey may be used to generate in-
terest by the local press which will be read by
potential complainants. You will also realize
that the problem is more widespread than you
thought, reinforcing your motivation, and
it will help to properly develop the formal
survey described in the next step.
STEP 5 DESIGN AND CONDUCT AN ATTITUDINAL AND NOISE MEASUREMENT SURVEY
Purpose: To independently determine the environmental noise
problem in your community, assess community opinion
about it, and find the willingness of citizens to
control it.
Output: Finished noise survey and social survey for use
in assessing the problem. It should contain a priority
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2-12
list of noise sources and health and welfare effects,
contain the willingness to pay for a proqram, whether
they need and want an ordinance, contain other data
for ordinance, such as the best time to quiet fixed so
and so forth.
: 1. The information-gathering process of Step 4
is also an informal learning process for the
Key Official. At this point, a more formal
and specific evaluation of the community needs
is required. A questionnaire is essential
and can be administered in three ways: (1)
placing the questions in the local newspaper
for clipout and return; (2) phoning the
questions to residents at random and record-
ing the results; and (3) interviewing resi-
dents at their homes. The first method is
the least reliable, since only a certain
class of individuals will respond; whereas,
the last method is the more reliable, but
also expensive. A phone survey, on the
other hand, is the quickest method to reach
large groups of people, but it limits the
number of questions that can be asked.
Read Chapter 6 to convince yourself of the
importance of determining the health and
welfare effects as the basis for a compre-
hensive noise ordinance. It appears that
much volunteer help may be available to
administer a questionnaire. When the question-
naire has been well thought out, trained
personnel are not necessary to administer it.
College or high school students may be used
if the teachers of environmentally associated
classes are convinced that the answers to
such a questionnaire could be useful to them.
In a survey in Boulder, Colorado, students
in the College of Environmental Design,
University of Colorado, did a very thorough
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2-13
job. The Junior Chamber of Commerce and
organizations of senior citizens also have
been known to help.
With regard to timing, the best time to
conduct a questionnaire in most of the U.S.
is spring, followed by summer. Outdoor
activities are commencing, and the change
from the closed-door winter environment to
the open windows and doors of spring brings
a fresh awareness of any environmental
noise problems.
The questions should be as brief and explicit
as possible, should cover all areas of concern,
and be written in such a way that the answers
would provide guidance as to what provisions
to include in an ordinance. They should provide
justification for either stopping or proceeding
further. The results of questionnaires are
generally surprising to reviewers because noise
is often ranked much higher than expected; it
may be due to the fact that noise intrudes on
people at their places of residence. Remember
that this questionnaire is a survey type,
meant to define the breadth and depth of a
problem quickly; it is not as accurate as a
scientifically devised and administered questionnaire.
Still, it will take about a week to administer.
It is important that distribution be sufficiently
.wide to cover as many potentially noise-impacted
regions as possible. Regions wtthin the com-
munity should be chosen to divide the areas
dominated by single noise sources. For example,
the area around an airport should be a special
region within the community. Within each region,
the questions should be addressed to residents
at random at their place of residence. A local
expert on sampling could help in ways to get
the best possible validity with the constraints
that have been applied.
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2-14
A questionnaire we have found helpful and
Informative for the purposes of enacting
a noise ordinance is given below. The
questionnaire addresses noise directly and
is written specifically to address the
questions that will arise when you attempt
to use Chapter 7. It will help establish
any health and welfare effects, establish
the sources to be regulated and give a
feel for citizen support. The assessment
of the questionnaire is discussed in Step 6B.
?. Formal sound level measurements are some-
times very helpful for demonstration
purposes, but we do not recommend that
a complete measurement survey be taken.
At this stage of the development, there
is not a great amount of additional in-
formation that can be obtained that is not
already available in publications. Step 14,
discussed later, makes use of sound equipment
for demonstration to municipal officials
which is a more appropriate time. However,
if you wish to make a community noise survey,
it should be done by experienced personnel to
avoid the errors, delays, and inaccuracies
that can easily occur with inexperienced
people making outdoor measurements. Choosing
what, where, and when to measure can be a
severe problem also since it can take an un-
due amount of time and effort to define those
factors. The opposition will always question
the validity and representativeness of any
data you collect, and in the proper public
forum for them. In summary, noise measure-
ments for familiarity with equipment are use-
ful , but if a formal noise survey is required
for some reason, it should be done profes-
sionally.
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2-15
QULSlJONNAIRE
Cart I Doinociraphy
1. Is your dwelling primarily single family
2. Sex of respondent: M F 3. Age:
LOCATION CODE
(For determining noise
impacting areas)
or multiple family
10-20
30-40
50-60
Own
Rent
20-30
40-50 _
Over 60
5. Years at this address: 0-1
Part II Residential Environment
; 1-5
5-10
Over 10
1. Give an overall rating to the residential area in which you live
Excellent Good Fair Poor
2. Rate these community services in your area.
Police Protection
Fire Protection
Recreation Facilities
Condition of Streets
Garbaqe Col lection
Neighborhood
Telephone Service
Public Transportation
3. Rank in order the four most pressing problems in your neighborhood by the use
of numbers, 1 being the most important.
vehicular air pollution
noise pollution
littering health care
crime
Poor housing
community air pollution
other (state)
Part II- Personal Reaction to Noise
1
N_
N_
N
1. Do you own a dog or dogs?
i
2. Do you think that governmental vehicles such as police cars or fire
trucks and contractors to the community government should be subject
to noise 1imits?
3. Do you think road and building construction should be required
to comply with any noise ordinance?
4. Do you think that public education on local environmental problems,
including noise pollution, is the responsibility of your community
government?
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c-li'
Rate by the scheme below to what degree the following sources of noise bother you:
1. Not Annoyed 2. Sometimes Annoyed 3. Regularly Annoyed 4. Highly Annoyed
Car racing events
Highway traffic
Motorcycles
Fire truck siren
Idling trucks
Radios, stereos, etc.
Building burglar alarms
Loading or unloading operations
Aircraft ground operations
Explosions or impacts
Aircraft flight operations
Motorboats or other watercraft
Street Sales
Automobiles
Police Sirens
Neighbors inside building
Places of public entertainment
Refuse compacting trucks
Road construction or repair
Vehicle repairs or testing
Heavy trucks & buses
Snowmobiles
Ambulance sirens
Factories or industrial activity
Exterior loudspeakers on vehicles or buildings
Automobile burglar alarms
Building construction or repair
Model airplanes or boats
Vibration
Vehicle horns
Off-Highway Vehicles
Home power equipment (lawnmowers)
Animals or pounds
Bells or chimes
6. Is there any particular time of day after which you become annoyed by noise?
a.m.
p.m.
If you were to allow more noise in the morning, such as garbage collection,
what time would you recomaend? a.m.
8. Do you or your family frequent places where there are high levels of noise
outside of your normal work? If so, what
9. Are there any noises, not caused by your family, that causes you to wake
at night? If so, what
10. Do you consider the neighborhood to be: very quiet fairly quiet
slightly noise noisy very noisy
11. Do you consider yourself to be: highly tolerant of noise slightly tolerant
indifferent slightly bothered by noise highly bothered
12. Most communities with effective noise control programs are spending between 10
and 30£ per capita per year. Would you be willing to pay that amount for quiet
in your community?
13. Name the most annoying source of noise you encounter in your daily life
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STEP 6 ASSESS THE PROBLEM INCLUDING FUTURE CHANGES
Purpose: To assess the local noise problem
relative to the citizens' health and
welfare, both with regard to present
and possible future noise problems.
6A FUTURE CHANGES
Purpose: Foreseeable changes in the noise
climate of the community caused by
new or modified sources need to be
considered in the development of a
noise ordinance. The noise ordinance
may be valueless if such noise sources
will not be regulated along with exist-
ing ones. This step suggests you
identify and collect information on
the new sources for inclusion in the
assessment.
Output:
1. List of potential new or modified noise
sources and their locations
2. Data on their noise characteristics
3. Estimate of their ability to be
regulated
4. Estimate of need for regulation
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2-18
Notes:
1. There are many changes that Introduce
additional noise into communities,
particularly residential areas. Some
are caused by the community government
itself, such as new siren types, siren
use policies, or road maintenance equip-
ment. Some are introduced with the
approval of the community government,
such as a new factory or a racetrack.
Some are introduced under conditions
where the municipal government has
questionable control, such as an airport
expansion or the addition at a new state
or interstate highway. Some changes are
introduced for other purposes but
result in more noise, for example the
purchase of faster or lighter equipment.
Generally, plans for these changes exist
in various departments and these depart-
ments must be interviewed to obtain this
information. In addition, state and
Federal agencies should be queried.
2. It is vital to assess the ability to
regulate the new source. Generally,
there is some way. If the problem is
big enough, say an aircraft engine test
facility, it may be the worst noise
problem in the community. If everything
else is regulated but that, the ordinance
will essentially become valueless when the
new source commences.
3. Consider the possibility of future Federal
and state regulations for those noise
sources where corrcnunity control is
questionable. It is a mistake to expect
Federal actions to solve these problems
you can solve yourself. See the Federal
Register, Vol. 39, No. 121, Friday,
June 21, 1974, pp. 22297-22299 for a list
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2-19
of products identified as major
sources of noise. In brief, they
are aircraft, construction and
transportation equipment,
particularly large trucks and
portable air compressors.
6B ASSESS THE PROBLEM
Purpose: The purpose of this step is to
determine whether an existing or
future noise problem exists and,
if so, to define it.
Output: 1. A list of health and welfare
effects in order of importance.
See the beginning of Chapter 4.
2. A list of noise sources in order
of importance.
3. A list of noise impacted areas
in the community.
4. Establishment of the need, desire,
and willingness to pay for a
community noise program.
Notes: 1. To develop the list of health and welfare
effects you should:
a. Use Figure 4.1 as the basic list and
delete these effects that are un-
important
b. Use as inputs the data gathered from
complaints to municipal, state, and
Federal agencies, the results of the
questionnaire, the informal survey
of the community, and any noise
measurements. Noise measurements
can be related to health & welfare
effects by using Figure 4jb. On
Hearing Loss, Fig. 4.4, on Speech
Interference, Figs. 4.7 and 4.8,
on Sleep Interference, and Fia. 4.9
on Annoyance.
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c. List by decreasing % of
population exposed to each
effect using the EPA criterion
as the threshold value. Esti-
mating the percentage will be
difficult, but use of a map
marked with major highways,
airports and fixed noise sources
will expedite such estimates.
d. The extensity of the total noise
problem can be defined by data
from the questionnaire (see item
4 below).
To develop the list of noise sources
you should:
a. Copy the list of sources from the
sample questionnaire provided above.
This list is derived from the sample
ordinance provisions in Chapter 7
so when you finish this list you
will be prepared to consider the
appropriate sections of Chapter 7.
b. Use as inputs the data gathered
from complaints to municipal,
county, state, and Federal agencies,
the results of the questionnaire,
the informal suryey of the cotmiunity
and any noise measurements.
c. Use a map to locate the most important
sources; it will help to establish
impacted areas also.
d. Develop the intensity and extensity
of annoyance by source (see item 4
below) to establish the priority list
of noise sources. Use Figure 4.8
to compare noise levels with annoyance.
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2-21
3. To identify the noise impacted areas:
a. Break the questionnaire data down
by location code to get the extensity
and intensity of total annoyance by
pre-selected region (see item 4 below).
b. Mark compla-ints by locations on
community map.
c. Mark location of important fixed and
moving sources on map.
d. Mark major freeways and arterial
highways.
e. Mark any industrial-residential
zone boundaries.
f. Add any information gained by
the informal survey.
4. Analyze the questionnaire by:
a. Establishing demographic percentages
b. Determining importance of noise
relative to other pollutants.
c. Determining the extensity of the
noise problem. This can be done
by finding the percentage of people
who are sometimes annoyed, regularly
annoyed, and highly annoyed from any
noise source. This should be broken
down by location code to isolate
impacted areas. This should also
be done by noise source.
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2-22
d. Determining the intensity of
the noise problem. This can be
done by finding the degree of
annoyance of those annoyed.
A simple linear weighting is
adequate for this assessment:
1 times number of people some-
times annoyed, 2 times the
number of people regularly
annoyed, and 3 times the
r>umber of people highly
annoyed. This will result in
a number for comparison among
the various noise sources and
impacted areas.
e. Finding the percent of respondents
who think an ordinance is needed
and the percent who are willing to
pay for some quiet.
5. At this point only the problem must
be assessed. It is tempting to draft
a preliminary ordinance, but it will
create more problems than it solves.
The only consideration to this point
has been the needs of the citizens
but, unfortunately, it is not the
only one, so by delaying the drafting
until all considerations are incorporated
there will be a minimum of confusion
and delay.
6. If there is a study group or local
experts, they can be of inestimable
value in the assessment.
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2-23
STEP 7 DEVELOP RECOMMENDATIONS
it is
Purpose: If there is a problem,/to develop goals
to protect the health and welfare of the
citizens, to determine what others have
done to regulate noise and to develop a
broad set of recommendations from which a
noise ordinance will result.
Output: A specific recommendation on which
noise sources identified as health and welfare
problems are to be regulated, that a noise
ordinance should be drafted by the Key Official
and that the health and welfare goals be approved.
7A DEVELOP HEALTH AND WELFARE GOALS
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2-25
ACTIONS OF OTHER GOVERNMENTAL AGENCIES
Purpose: To bring together material showing what
other governments have already done to
control community noise.
Output: 1. List of communities & states
that have regulated noise,
showing which sources they
have regulated, approximate
program costs, legal problems
encountered, and economic costs
to the violators.
2. The present and future actions of
the Federal and state government
that will have impact on community
noise programs.
Notes: 1. This material will be valuable later in
Step 12 when cost and manpower estimates
are made.
2. The material can give the decision makers
confidence that noise ordinances covering
the sources in the recommendations can be
effectively enforced.
3. It will help to clarify the difference
between occupational and environmental
noise regulations.
4. Survey noise ordinances of other communities
to determine the number of communities that
have regulations similar to what you are
contemplating. The references at the end
of Chapter 7 contain a list of ordinances
that we used as a partial base for the
chapter and should be helpful reading.
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2-26
Correspondence with these communities
on their enforcement experience and
statistics will be very helpful when
you finally present the ordinance at a
public hearing. Chapter 7 analyzes the
various components of the noise ordinance
so you need not determine the competence
of any ordinance until.the drafting stage.
5. Federal actions on noise are briefly
summarized below and details should be
obtained from the local office:
U.S. Environmental Protection Agency -
Noise Control Act of 1972.
Will control the noise of railroads and
interstate motor carriers, will recommend
standards on aircraft noise and will set
standards for major sources of noise
distributed in commerce.
Federal Highway Administration - Policy
and Procedures Memorandum 90-2.
Sets standards for highway noise oh
Federally-assisted projects.
Federal Aviation Administration.
Sets standards for aircraft and
aircraft-related noise.
Occupational Safety and Health Administration -
OSH Act. Sets noise standards for the
workplace.
Dept. of Housing & Urban Development -
Circular 1390.2
Controls the received noise at residential
units for Federally-sponsored projects.
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2-27
RECOMMENDATIONS FOR ACTION
Purpose: Based on the assessment,
recommendations for future actions
must be formulated, preferably in
writing.
Output: A recommendation as to whether or
not the Key Official should conmence
development of a noise program to
achieve the health and welfare goals
and to draft a comprehensive noise
ordinance.
Notes:
1. The recommendations should be in writing and
should contain a summary of all the previous
steps of this phase that lead to the recom-
mendation. A review of the problem assess-
ment, particularly the list of health and
welfare effects, noise sources, and impacted
areas should be included.
2. The recommendations should be based on the
needs and desires of the citizenry only,
and, therefore, on the health and welfare
goals.
3. The recommendations should contain a list
of those sources for which regulation is
suggested. This will help define the
composition of the opposition group who
will later be asked to provide inputs.
The list may be more inclusive than the
list of noise sources made in the problem
assessment, and any difference should be
explained. One example might be garbage
trucks, which may be noisy but few
complaints are registered.
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If the recommendation will be to
draft an ordinance, the following
points should be made and substantiated:
a. There is a need based on health and
welfare and that need will ultimately
be met by successively modifying the
noise ordinance over time until the
health and welfare goals are met.
b. It is enforceable, not too costly,
and does not work economic hardship
on violators, based on the actions
of other communities.
c. The problem is caused by the sources
in the list made earlier.
d. There are other communities that
have legally controlled such sources.
e. It is technically feasible to reduce
noi se.
f. Environmental noise is related to
occupational noise, but must be
regulated differently.
g. No other levels of government will
solve the problem for you.
h. There is broad citizen support, based
on the questionnaire.
i. There is sufficient information and
assistance available to draft an
ordinance suited to the community.
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STEP 8 REPORT TO DECISION MAKERS
Purpose: To obtain the concurrence of the decision makers,
either City Council, Mayor, or City Manager, with
your recommendations.
Outputs: 1. Decision to stop study or go on and develop
a draft ordinance.
2. Approval of Health and Welfare Goals
Notes: 1. In any verbal report, speak primarily to the development
of a program to solve the problem, the ordinance being only
a means of implementing the program. Avoid discussion
of the enforcement agency, if possible. When the
draft ordinance is presented it will be easier to make
the case for the lead agency to be other than police.
See the discussion section under Article VIII of
Chapter 7 for some arguments on the enforcement agency.
2* Avoid getting snagged into technical details of acoustics.
It is possible to spend an entire evening on the dif-
ference between sound pressure level and decibels, and
on the definition of ambient. A simple chart re-
lating levels to common experience 1s all that should
be necessary.
Since the program will only be developed in the next
phase of the work there is no need to have the
opposition involved since there is nothing to oppose
as yet. An open meeting, with people adversely
affected by noise present, is preferable, in order to
make the point that there is a problem. There is a
tendency for the public to think things are goinq well
and that public support is no longer needed, so you will
need to once again solicit their attendance at the meeting.
It may be necessary to have a noise demonstration at
this point (See Step 14 for some notes on that).
Communities have given both indoor and outdoor
demonstrations of the sources they think need to be
controlled. It also shows the relative simplicity of
the measurement process and will give the decision
makers a feel for what is noisy and what is not.
Demonstrations generally are an asset to any pre-
sentation recommending a noise ordinance.
3.
4.
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2-30
5. Most communities present their report verbally,
making the points listed in Step 7C above and
using the following visual presentations:
a. A map of the city showing where noise complaints
have arisen and, if possible, the source of the
complaint.
b. A map of the city showing freeways, high speed
major arterials, and the noise contours of any
local airport (supplied by the airport, if it
is big enough).
c. A map of the city showing major fixed noise
noise sources, and the boundary line between
industrial and residential zones.
d. A map of the city showing any well-defined
noise impacted areas and their probable cause.
e. A chart of the noise extensity in the community by
source.
f. A chart of the noise intensity in the community
by source.
g. A chart showing other pertinent results of the
questionnai re.
h. A chart with the health and welfare effects of
noise and the estimated percent of the population
influenced by them.
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PHASE III: DEVELOPMENT OF THE ORDINANCE
Purpose: You have now been given the dubious task of developing a
noise ordinance which will best meet the health and welfare
goals considering the economic, political, and technical
realities of the situation.
Output: An acceptable noise ordinance which is also effectively
enforceable and an approved program for enforcement.
STEP 9 DECIDE ON SCOPE OF PROGRAM AND ENFORCEMENT METHODS
Purpose: To define how comprehensive the ordinance
is to be and how it is to be enforced. The
many minor decisions that need to be made will
come from this definition.
Output: 1. The immediate objectives of the ordinance
2. An outline of the sources to be regulated,
along with the method to be used for each, and
the proposed enforcement agency.
Notes: 1. A program is the action phase that is given
authority by an ordinance. The program needs
to be defined first so that the ordinance will
contain the needed authority to implement it.
The primary objective of a noise
control program should be to achieve quiet in
the community. The first step 1n that program
is the ordinance, which we deal with almost
solely in this document. The action part of the
program will have enforcement activities (about
40% 1n many communities), school and public
education activities (about 40% in smaller
conmunitles), administrative actions (about 10%).
Other parts of the program can be: (1) assistance
to other communities, and (2) advice to distri-
butors of noise equipment, rental stores, truckers,
and motorcyclists on how to comply with the ordinance.
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2. Decide on the type of ordinance. The
simplest type is an enabling ordinance:
it would establish an enforcement agency
with legal authority to control excessive
noise and would contain provisions that
describe those sources that require control,
but it would not contain many specifics,
such as numerical sound level limits. The
latter are left to be written by the enforce-
ment agency, after considering all relevant
factors. An enabling ordinance has certain
advantages. It does not require compre-
hensive knowledge of the noise problem
before enactment. Because it is not
detailed, arguments about specifics are
minimized, and it may even be possible to
pass such an ordinance without great public
awareness. Public hearings, however, are an
asset for enabling ordinances. The omission
of specific numerical limits allows regu-
lations to be issued to cover the desired
noise sources after a reasonable period of
study and debate. The slow process of
making decisions on numerical limits for
noise sources, before the ordinance is
passed, is thereby avoided. In addition,
as the economic feasibility of noise control
improves, the limits can be easily lowered
to afford maximum protection to citizens.
The weakness of an enabling ordinance is that
it requires a high degree of confidence in the
city administration by the City Council, which
may or may not be present, and it will be slow
bringing into the enforcement stage.
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The specific (comprehensive or objective)
ordinance, detailinq control methods for
all appropriate sources of noise, is more
complicated. Use of this workbook helps
to simplify developing this type of ordinance.
The main purpose of the workbook will have
been served if this proves true. The
advantage of the specific ordinance is that
city councils, as well as those adversely
affected by noise, are more prone to accept
it over the enabling ordinance. In addition,
the enforcement agency does not have to be
legislatively oriented since the regulations
are already written; the personnel of the
agency can be chosen for their ability to
enforce the ordinance rather than their
ability to develop it, since it will have
been written before their being hired. The
task, of finding enforcement personnel is
simplified as a result. The main disadvantage
of a specific ordinance is that it requires
a lengthy developmental process, and errors,
once incorporated, are more difficult to
remove. Chapter 7 is primarily concerned
with the explanation of provisions for this
type of ordinance, so that these errors
will be minimized.
3. It is mandatory to decide on an effective
enforcement methodology. ( See Chapter 7,
Article VIII, Discussion Section on Method
of Enforcement.) An active program will re-
quire more people and, therefore, more money.
Although the severity of enforcement should
not be reflected in the ordinance, it creeps
in in many ways, e.g., it is more likely that
a 6 p.m. curfew will be enforced than a 10 p.m.
one, just as it is more likely for you to get a
speeding ticket when the road is empty than when
it is rush hour. It is not sufficient to write
an ordinance that will be passed, nor is it
sufficient to design an enforcement program
which does not take into account the political
forces within the community. The financial
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capabilities of the community will be
a factor in the size of the enforcement
program, and competition from other
programs can be a source of problems.
These and other factors must be fed
into the process of developing an
ordinance so that it will be possible
to avoid having a comprehensive
ordinance which cannot be effectively
enforced.
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STEP 10 DEVELOP ROUGH DRAFT OF ORDINANCE
Purpose: To develop an actual ordinance that is
based only on the protection of the health
and welfare of the citizens, taking into
account feasible short-term goals, enforce-
ment methodology and the type of ordinance
desired.
Output: Working draft ordinance that can be
reviewed by all interested parties prior to
submission.
Notes: 1. At this point, you should be ready to
read the introduction to, and the
components of, Chapter 7 that relate
to the sources you wish to regulate.
It is important to read the discussion
in front of each ordinance component to
obtain a feel for which alternative means
of expression you desire. The notes
below relate to the types of questions
that will arise as you proceed through
each article of Chapter 7.
2. Article I. Short Title. A title for the
ordinance may or may not be necessary.
See page
3. Article II. Declaration of Findings and
Policy. This article is necessary since it
establishes the basis in law for the ordinance.
We provide two alternatives. See page
4. Article III. Definitions and Standards.
We provide a comprehensive list of definitions
that apply to ordinances. You will find they
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are at slight variance with the
scientific definitions because
those definitions were not developed
with noise ordinances in mind. You
should include only those you need
and to assist you in doing this, each
ordinance component has a list of
needed definitions after it, to be
added to the general ones recommended
in Article III. The fewer the defini-
tions, the more clear the ordinance
will be. This article will be written
after all other articles.
5. Article IV. Agencies. Where necessary,
especially in larger communities, the
relationship of the designated enforce-
ment agency with the other departments
of the municipal government needs to be
defined. Inter-departmental agreements
should be seriously considered at this
point so that appropriate cooperation is
mandated in writing by the ordinance,
particularly with regard to siren usage
and other noisy municipal operations.
Barking dog control should be passed to
an animal control office or the police.
Those agreements not put into the
ordinance should be written for internal
distribution. The enforcement agency
and methodology must be decided upon.
Part of the methodology will be determined
by what is written in the enforcement
articles and so it must await those
decisions. Sections 4.7 and 4.8 on
Contracts and Low Noise Emission Products
should be seriously considered.
6.. Article V. Authority and Duties.
In smaller communities this article is not
included as a rule, but there is good
reason to include many of the concepts
even if severely abbreviated from that
presented in Chapter 7. In larger com-
munities most of the provisions become
necessary at one point or the other.
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7- Article VI. Noises Prohibited.
This article is the general nuisance
article with Section 6.1 being the
blanket provision to cover any cases
not specifically mentioned elsewhere.
Even though it is seldom, if ever,
used by communities with comprehensive
noise ordinances, it does close a loop-
hole. Section 6.2 is a specific
enumeration of nuisance sources. Most
of them are noise sources that are
difficult to measure, such as barking
dogs and construction sites, or do not
readily fit into the other articles,
i.e., garbage trucks, and must be handled
separately. Your list of noise sources
should tell which of these to choose.
Time limits chosen here shall be con-
sistent with other sections (See Note 14
below).
8. Article VII. Exceptions and Permits.
If there are noise sources which are
considered impractical to control at
present, they should be given complete
exemption in the rough draft ordinance
so the issue is clear. Sirens are not
one of that class as you will note in
the discussion of Chapter 7. Pro-
ordinance individuals will have an
opportunity to review it and object in Step 11.
We recommend that no specific noise
source or class be given a variance
but that a temporary exemption pro-
cedure be developed. Such a procedure
avoids the "he got-one-why can't-I"
problem. The penalties for violations
need to be worked out at this point and
included in the draft. Enforcement data
from other communities can be used with
the proposed penalty values to estimate
the income from such an ordinance.
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9, Article VIII, Noise Levels by Land Use.
This and the following article on motor
vehicles are thp heart of a comprehensive
noise ordinance. If only these two articles
survive a review process with a general
nuisance statement, you will have a workable
noise ordinance. We strongly recommend this
article be well written, as you might tell
by the extensive discussion in Chapter 7. You
will need to analyze the data provided,
other ordinances, and the community survey
results, to arrive at a set of numbers for
inclusion. When you have them, compare them
with other local communities to avoid having
highly inconsistent values. Time limits
should be consistent with other provisions
of the noise ordinance and with other
communities. (For guidance see Note 14 below)
Enforcement methodology will be determined
by how this article is written.
10. Article IX. Motor Vehicle Noise Levels.
The terminology of this article is fairly
standard and you need to choose the set of
numbers for the tables. The data we have
provided will give you some guidance, in
addition to any measurements you may have
made, or what other ordinances have. The
interstate commerce motor carriers levels are
fixed by Federal regulation, but the issue
of preemption is not yet clear.
11. Article X. Building Noise Levels.
Consider an addition to the building code
even in its simplest form. The increase in
condominium usage has brought the environmental
(or property line) problem into buildings,
and many EPO's are asked to solve disturbances
in buildings. These disturbances range from
loud parties to obvious building flaws, such
as paper thin walls. His inability to act in
these circumstances tends to discredit the
value of the ordinance because environmental
noise is most important at homes and a lot
of homes are apartments or condominiums.
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Unfortunately, we do not have a
recommendation for an objective
method of measuring building noise
problems. Recent recommended codes,
such as the Uniform Building Code,
have provisions that limit the noise
transmission path of certain partitions
only (STC) and not the flanking paths
that make the true noise isolation, we hope
to have a section in the near future.
12. Article XI Land Use. This article
pertains to noise prevention by requiring
new construction and modifications to go
through a review process. Noise prevention
is certainly very important, but there
are some political problems with any
review process. This is discussed in
Chapter 7.
13. Article XII Additional Provisions.
These are the penalty and other legal
provisions which make the ordinance en-
forceable, and most communities include
all the sections provided in their
ordinances.
14. Choose a reasonable set of time limits
for the various sources to be controlled.
Chapter 7 contains a number of suggested
ordinance components that require the use
of time limits, either for reduction or
prohibition of noise emission. There are
three major time divisions during the day
for noise purposes: day (7 a.m. - 6-7 p.m.),
evening (6-7 p.m. - 10 p.m.), and night
(10 p.m. - 7 a.m.). Most communities, to
date, if they have time limits, have only
two: day (7 a.m. - 10 p.m.) and night
(10 p.m. - 7 a.m.). The U.S. Federal
Aviation Administration uses the limits:
7 a.m. - 10 p.m., 10 p.m. - 7 a.m. for
aircraft noise purposes. The night noise
levels of aircraft are weighted more heavily
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to account for their greater annoyance due
to sleep interference. Your community may
wish to deviate from this pattern, so con-
sultation with neighboring communities is
important to develop some standardization.
You should consider whether special quiet
days are to be included, such as Saturdays,
Sundays, and legal holidays. They may be
lumped with night levels.
15. After the rough draft is put together, you
must analyze it with regard to state and
Federal laws or regulations to insure that
it is consonant with them. If there are
other communities with municipal noise
ordinances, you should balance the com-
munities' needs with the need for con-
sistency with the laws of these other
communities. Particular attention must
be paid to pre-emptive legislation, either
existing or pending. Organized groups in
opposition to the ordinance will be abreast
of such legislation and may attempt to
nullify the entire ordinance on this basis.
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STEP 11 REVIEW OF ROUGH DRAFT
Purpose: To allow all Interested parties, both pro and
con, to review the draft, make comments and
generally strengthen the ordinance.
Output: A list of comments, both pro and con,
from which a revised draft may be written.
Notes:
1. The support and advice of citizens and citizen
groups can be a big boost when an ordinance
comes up for hearings.
2. Expert help, legal, technical and political, can
be of assistance in evaluation of any changes you
may have made from the workbook text. The help
can provide justification for the approach taken
when the opposition wishes to change things.
3. The opposition can be any number of individuals
or groups. Racetrack fans can be temporarily
organized to fight an ordinance; car and truck
manufacturers have been known to lobby against community noise
ordinances for one reason or another; motorcycle
dealers and local factory owners may fight you
also. Up to this point, the primary concern has
been the welfare of the citizens with regard to
noise, and the draft should reflect this fact.
Explaining fully the draft provisions and how
they derived from your assessment of the
problem, will help the opposition to understand
the concerns expressed in the draft. From this
point on, the opposition should be closely in-
volved so that by the time Step 15 arrives,
they will not object as strongly as they had.
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4. The City Attorney's staff will be needed
to rework some of the draft to conform
with other ordinances and with city policy
or procedures. Most importantly, the
draftor should not be an attorney because
his interest is primarily in the legality
of the document and not in solving the
noise problem.
5. The proposed enforcement agency or agencies
should make a detailed review of the draft
to insure that they understand their potential
future involvement. Other agencies, Federal,
state and local, and other municipal depart-
ments should be asked for comments to insure
that pre-emption will not interfere and that
consistency with other regulations will occur.
6. Any meetings held are best held with each group
individually in order to maximize accomplishment.
Large meetings, containing people of diverse view-
points, degenerate into random noise sessions.
STEP REVISION OF DRAFT
Purpose: To put the comments into the ordinance to
strengthen it, or to develop arguments for
not responding to a comment. The revised draft
should be used to estimate the cost and the
required manpower.
Output: A draft with some consensus of the in-
terested parties to be a politically workable
ordinance.
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Notes:
1. The draft revision should incorporate all
helpful comments and may have to Include
some concessions. Any comments that are
not incorporated must be answered finally
to the satisfaction of the City Council.
2. Presuming some measure of agreement with
the enforcement agencies has been reached,
cost and manpower estimates must be made.
In addition, income estimates should be
developed.
3. A second review process may be necessary
if extensive changes are made. It is always
difficult when a disagreement occurs at a
study session with City Council and the
opponents state that they did not see the
revised draft.
final
4. Copies of the/revised draft should be sent
to the Council and a study session requested.
STEP 13 STUDY SESSION WITH CITY COUNCIL
Purpose: To acquaint the City Council with the
provisions of the proposed ordinance,
their implications and how the ordinance
will be used to meet the long-range goals
set to solve the noise problem.
Output: Comments by the City Council on the
advisability and adequacy of the ordinance.
You should particularly get general approval.
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Notes:
1. To accomplish the objective, it is necessary
to fully inform the Council on the comments
previously made, both pro and con. The
opposition will have access to Council outside
the study session, and key questions will be
asked.
2. It is not necessary to review the technical
definitions since that should have been
covered in Step 8.
3. Any groups that have been opposed to the
ordinance but have changed their viewpoint
should be discussed as well as the viewpoints
of the opposition.
4. A suggestion for a demonstration should be
made. The demonstration should be as soon
after the study session as possible.
5. Legal and technical backup is mandatory at
this session. Questions will always be
asked for which the Key Official will not
have the answers. A few key resource people
will make the presentation go well and they
will give the Key Official the confidence he
needs at this point. Federal and state agency
people and community individuals known to the
Council are good resource people if they have
the needed knowledge.
STEP 14 NOISE DEMONSTRATION
Purpose: To give the City Council confidence that the
proposed ordinance is reasonable and enforceable
and to acquaint the municipal judges with the
ordinance and the measurement methodology.
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Notes:
1. The enforcement agency should borrow equipment
from those who have it already, such as the
U.S. EPA and state or local agencies.
2. Volunteers to drive typical vehicles to be
regulated are needed. Examples of vehicles
in excess of the proposed levels should be
shown and the whole enforcement sequence
should be demonstrated. Motorcycle associations
will volunteer to drive their vehicles to
show how they can be driven quietly.
3. The spectators at such a demonstration should
be not only the City Council, but also members
of affected industries, police officials, other
interested parties, and most importantly, the
municipal judges to whom the few initial cases
will come. These judges require a thorough
explanation of the procedures and particularly
with reference to other similar violations,
such as speeding. If they have confidence in
your procedures, the first few cases will go
smoothly.
4. Certain procedures should be employed in making
measurements. They are
a. Avoid having people around the microphone.
Yourself or observers have a tendency to
crowd around an SLM and this will change the
readings because of reflections and excessive
talking. A remote microphone or a remote
recording device is helpful here.
b. Avoid areas with buildings and shrubbery.
Although ground reflections are perfectly
satisfactory to most observers, buildings
and shrubbery raise a host of questions
concerning their influence on measurements.
In many cases the effect is small, but to
avoid prolonged discussion it is better to
avoid such measurement sites.
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c. The microphone face should point upward and
be at approximate eye leveK
Not only is it more readable, but the readings
are more reliable.
d. For fluctuating sounds use a graphic level recorder.
The dynamic range of most SLM's are not sufficient
to show the broad range of amplitudes found in an
environmental noise.
e. Always use a wind screen. Whether there is wind
or not, it is good practice to use a wind screen
at all times, both for technical and political
reasons.
f. Do not attempt to demonstrate measurement of
impulsive sounds without an impulsive SLM.
In mnst. enforcement Drograms, impulsive sounds
are seldom encountered under circumstances where
precise measurements are necessary. Omission of
such sources in demonstrations keeps unofficial
budget estimates low in the minds of observers.
STEP 15 FORMAL PRESENTATION
Purpose: To formally present the ordinance for first
reading at an open City Council meeting in
such a way as to maximize the probability of
passage.
Output: The ordinance passed on first reading.
Notes:
1. It is absolutely essential that all the pro-ordinance
individuals be present, including everyone who was in
any way involved. This Includes people from other
agencies, experts, and citizen groups. Only selected
representatives of community groups need to speak in
favor of the ordinance; the remaining individuals not
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only fill up the Council chambers to show
interest in the ordinance, but also serve
to insure that no question asked by anyone
will go unanswered.
2. One standard tactic of the opposition who
wish to remain invisible is to get the
passage postponed to obtain "further In-
formation." With everyone present to
answer questions, you must press for a
decision at this meeting. Delay will
only allow more opportunity for delay.
3. The presentation should be by the Key
Official and it should be kept technically
simple and brief. Highly technical pre-
sentations raise more questions than you
can answer in a City Council meeting.
4. Any support by persons or groups who
formerly expressed opposition should
be brought out.
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CHAPTER 3
TfCHNICAL 7TRMIN0! OfiY
This chapter provides some description of sound level meters
and the terminology necessary for their use and, therefore, for a
noise ordinance. We attempt to explain the deciBel scale without
excessive formulas or mathematics so that the information may be
used for explanations to others, such as City Council. It is necessary
to read this chapter before reading Chapters 4 and 7.
Intended Readership: Those individuals charged with
developing the noise ordinance
or explaining terminology to
others.
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Section 3.1 Introduction - - 3-4
3.1.1 Purpose of Chapter - - 3-4
3.1.2 Sound vs. Noise 3-4
3.1.3 Some Characteristics of Sound 3-5
Section 3.2 Sound Level Meters 3-8
Section 3.3 Sound Pressure 3-10
3.3.1 Sound Variables --- 3-10
3.3.2 Units of Sound Pressure 3-11
Section 3.4 The dB Scale - 3-12
3.4.1 What it is — 3-12
3.4.2 Comparison with Linear Scale 3-12
3.4.3 Advantages and Disadvantages of dB Scale 3-12
Section 3.5 Sound Pressure Levels vs. deci Bels 3-14
3.5.1 Definition of Sound Pressure Level 3-14
3.5.2 Addition of Unrelated Sounds 3-16
3.5.3 Subtraction of Unrelated Sounds 3-1?
Section 3.6 Frequency Weiqhting of Sound Pressure Levels 3-1?
Section 3.7 Fluctuating Sounds 3-2C
3.7.1 Why Measure Fluctuating Sounds 3-2C
3.7.2 Measuring Fluctuating Sounds - 3-21
3.7.3 Historqrams 3-2^
3.7.4 Cumlative Distributions - Lp - 3-21
3.7.5 Energy Equivalent Sound Level - Leg 3-21
3.7.6 Day-Night Average Sound Level - Ldn 3-2!
REFERENCE List of Definitions and Important Terms 3-2
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3-4
3.1 Introduction
3.1.1 Purpose of the Chapter
The purpose of this chapter is not to acquaint the reader
with all the terminology of acoustics, but rather to acquaint them
with only those terms which will be seen in the ordinance sections
to follow and to distinguish those terms from others that may be
used erroneously. The terms are all presented from the users' view-
point, i.e., everything is tied to how it can be measured on a sound
level meter, the basic tool for noise ordinance enforcement.
Not all sections need to be studied by all readers, some
sections are tied to specific sections of Chapter 7 and need only
be read if that section is to be considered for inclusion Into the
ordinance. The suggested readership is given
at each section with a tie to the pertinent sections
of Chapter 7 for later use.
3.1.2 Sound vs. Noise (General reader)
In its simplest form, sound is a physical phenomenon which
is caused by a "source" and travels away from that source at the
speed of sound (about 1128 ft/sec or 770 mph) in the form of waves.
It is similar to the waves caused by a rock thrown into a quiet pool,
but different in that sound waves compress the air unlike water waves.
Based on this brief definition we can see that sound is a physical or
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3-5
objective occurrence capable of being measured and analyzed.
On the other hand, noise has been called unwanted sound or sound
that causes or tends to cause adverse psychological or physiological
effects in human beings. Noise is purely a subjective occurrence in
more
the first definition and is mostly subjective or at least/difficult
(as compared with sound)
to quantify/inthe second definition. For this reason, many of the
provisions of the "noise" ordinance are entitled "sound." Since most
of the concern, but certainly not all of it, is about annoyance in
the enforcement of a noise ordinance, the subjective aspect of noise
is always present and it presents legal difficulties that must be
solved 1n court. Consequently, wherever it is possible, the word
"sound" is used, and the word "noise" is used as infrequently as
possible. The relationship between the two is given in the legis-
lative declaration. (See Article II of Chapter 7)
3.1.3 Some Characteristics of Sound (Key Official)
Wherever possible, the provisions recommended are quantitative,
that is, they relate to that which can be measured by a sound level
meter. In order to make useful measurements, an ordinance must cover
each of the characteristics of sound that can give rise to annoyance.
The major characteristics are given below:
1. Amplitude, loudness or level. Each of these words generally
describes the magnitude of the sound, even though each is
technically different as we shall see later. Level is used
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3-6
most often and we shall use sound level or noise level to
describe the magnitude. A quantitative noise ordinance must
set upper limits on the levels of sound received by citizens
for reasons set forth in Chapter 4. We discuss the measure-
ment of sound magnitude in more detail in Sections 3.2 to
3.5 below.
2. Frequency or Frequency Distribution. The rate at which a
source vibrates determines the frequency of the sound generated.
If the frequency is either above or below the audio frequency
spectrum, we generally do not care about the magnitude of the
sound since it cannot be heard. The audio frequency spectrum
does not have precisely defined limits: the ear becomes progres-
sively insensitive to sound at frequencies below 400 Hertz
(abbreviated Hz, and is identical to c.p.s., cycles per second)
and above 8000 Hz. For general purposes, we can say it ranges
from 20 to 20,000 Hz. Thus, for a low frequency sound to be
equally as loud subjectively as, say, a 1000 Hz tone, the
magnitude of the low frequency sound must be much greater than
that of the tone. In a noise ordinance then, it is important
to have specific frequency limits in the measurement process,
and we show what those limits are in Section 3.6.
There are two major subcategories of frequencies in the
audio frequency spectrum that need to be addressed. The first
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3-7
is called a pure tone or a sequence of harmonically related
pure tones called a periodic tone. A pure tone consists of a
single frequency or single pitch as you might find in a whistle
or in a pitch pipe. Very few environmental sound sources have
we
only one pitch. Any / think are making a tone almost always
make a periodic tone. Examples: police sirens, railroad
whistles, or whining fans. The second category is sounds
that do not contain a detectable tone, they are called broad
band or random sound (and sometimes erroneously random noise
or white noise). Most environmental sources make varying
amounts of both categories of sound. The importance of dis-
tinguishing between the two is that tones are found to be
much more annoying to people and they are a greater cause of
when
complaints/at the same level as broad band sound. Compare air
conditioner sound with a teapot whistle, which stirs you into
action fast. A noise ordinance may take this difference into
account in a simple way. (See Section 8.3 of Chapter 7)
3. Impulsive Sounds. Most sounds in the environment are continuous
in that they persist for many minutes and the level may
vary during the period, such as a lawnmower, but it is certainly
distinguishable from a gunshot or an explosion which are
impulsive sounds. Such sounds must be handled separately in
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a noise ordinance for two reasons: (1) impulsive sounds
are generally loud and cause a startle response in people
and; (2) only special sound level meters can accurately
measure such short duration, high level sounds.
Fluctuating Sounds. Most sounds in the environment have
a magnitude that varies from minute to minute. Experience
has shown that sounds that vary greatly during a given time
period are a greater source of annoyance than a steady sound.
A good quantitative noise ordinance will take this into account
where it can. We discuss this point in more detail in Section
3.7 below and again in the appropriate sections of Chapter 7.
Sound Level Meters (Key Official)
The information in this section can be used by the Key
Official to explain the general workings of sound level meters
(SLM) to others. It would be valuable if a SLM could be borrowed
from someone while you read this section.
Sound level meters are instruments that measure the
magnitude or level of sound in the range of frequencies that the
meter is set to accept. Typical field instruments are shown in
Figure 3-1. These instruments are small, lightweight, battery
powered, and relatively simple to operate. To operate these
meters, the On-Off switch is turned on and the battery reserve
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3-9
1s checked by pressing the I3ATT switch. If the batteries
are low, the case can be opened either by hand or with a
coin to remove and replace the battery or batteries. Next,
the calibration of the instrument must be checked. Figure 3-2
When
shows two makes of calibrators. the calibrator and sound
level meter are turned on, the calibrator is placed over the
microphone (which is the cylindrical object at the end of the
SLM) and the calibrator setting should be read. If it is not,
a simple screwdriver adjustment corrects the meter and the
instrument is ready for use. Each of the meters has a switch
setting to adjust the frequency limits of the meter; they are
marked A, B, and C and are explained in Section 3.6 below. We
will use the "A scale" or "A weighting" exclusively. The meter
has a "Fast" and "Slow" setting which is normally set on slow.
The only remaining action is to read the sound level in the
window of the meter.
The sound level of concern in most noise ordinances varies
from 50 to 100. We explain exactly what these numbers are in
Section 3.4 and 3.5 below. Most meters are set to show only a
range of ten, e.g., 60 to 70 in the meter window, so there is a
side knob which adjusts the range shown in the window. The range
limits appear in the window when the knob is moved ^and the knob
is moved until the needle points toward a number in the range shown.
-------
3-10
If you have a SLM and can observe It, you might qet
a measure of the sound level. The explanations 1n Sections 3.3
to 3.6 below explain what that number actually means. You are
likely to find that the dial reading will fluctuate and
sometimes such that it will go off the scale on either end.
The source of these level fluctuations can be any number of
things, a passing car or airplane. The assignment of a sound
level number
for comparison with the ordinance
numbers requires manipulating the fluctuating reading, and we
discuss that more fully in Section 3.7.
Sound Pressure (Key Official, Section 3.2.31, Chapter 7)
3.3.1 Choosing Sound Pressure to Measure
When sound is emitted by a source, the energy in that
outgoing wave causes several properties of the air to change
such as the pressure, density, and temperature. Through ex-
perience, the most reliable mechanical device for changing
sound energy to electrical energy is a diaphragm that responds
to the pressure fluctuations. Thus, determining the magnitude
of sound is tied to measuring sound pressure, and noise
~
ordinances reflect this relationship.
*Sound pressure is the instantaneous difference between the
actual time-varying atmospheric pressure and the average
or barometric pressure. As we shall see, that difference
i s very smal1.
-------
Microphone
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-------
3-11
The microphone of a SLM changes the pressure fluctuations
in the air to voltage fluctuation inside the meter. See bottom
part of Figure 3-4. Since the pressure charges are so small
(in many cases only one millionth as great as the atmospheric
pressure), the microphone must be very sensitive in order to
generate voltages big enough for the meter to use. Because of
this great care must be exercised in handling microphones (don't
blow on them, touch them, or drop them) and they should be
calibrated frequently.
3.3.?. Units of Sound Pressure
Since an objective or quantitative noise ordinance must
be tied to sound pressure, it is important to have the units
and reference sound pressure correctly defined. We are used
to expressing pressure in pounds per square inch (psi), but in
acoustics the metric system has been used for some time and the
unit of pressure is the Pascal, which, like "Hertz," is not
self-explanatory.
-------
it
Fl9 1. ptrtonphont
figure 3-2 Sound OUbrators
-------
3-12
1 Pascal ¦= 1 Newton/meter^
and 1 Newton - 4.448 pounds of force
1 Meter = 3.28 feet
so 1 Pascal = 0.00287 psi
or 1 psi = 348 Pascals
The reference sound pressure for noise ordinances is inter-
nationally standardized and is
p =20 microPascalc - 20 x 10"® Pascals - 10"® N/m^
(reference)
That number should appear in the definitions of the ordinance
and it appears in our definition 7.2.32 of Chapter 7.
The dB Scale (Key Official, Sec. 3.2.7 Chapter 7)
3.4.1 What it is
There is much confusion in the mind of the newcomer, and
justifiably so, about the difference between dB's and sound levels.
We explain what the dB scale is here and compare it with sound
levels in Section 3.5. The dB scale, abbreviated from decibel,
is simply a means of compressing a large range of numbers into
a smaller range. In acoustics, the actual range of sound pressures
encountered may be as large as 10 billion. This range is difficult
to graph or put on a meter. By using the dB scale, we can reduce
this range to one that is more manageable: 0 to 100. The
mathematical (and electrical) operation which does this is
-------
3-13
called the logarithm. If we have a number N and if
Y = 10 LOGjqN, then Y is the logarithmic equivalent
of N and we may say "Y decibels" to express this log
operation. Note that the dB scale can be applied to
anything and it sometimes is, so whenever we use dB
in noise ordinances we only imply that we have used
the dB scale rather than a linear one.
3.4.2 Comparison with Linear Scale
To get a feel for this scale, we show in Figure
3-3 a comparison between it and the linear or actual scale
of numbers it represents. Originally, the Bel was used (it
was named to honor Alexander Graham Bell), but because the
unit was too large it was divided by 10 to get the deciBel
(one-tenth Bel). We see in the fiqure that the Bel or
deciBel number is related to the power of ten required to
make the actual number. Everytime the deciBel increases
by ten the actual number is multiplied by ten. Sound level
meters have this conversion factor built into them, as shown
in Figure 3-4. The use of this scale for sound measurements
is given in Section 3.5.
3.4.3 Advantages and Disadvantages of dB scale
The primary advantage of the dB scale is that large
ranges of numbers are compressed into a smaller range. You
-------
3-14
can see in Figure 3-3 that a range of 10 billion to one
in sound energy is not uncommon. The human mind can
handle the large range found in acoustics without failure,
but the SLM cannot. If we had a SLM with a linear scale,
we would see no needle motion until the loudest sound
occurred and then the needle would jump off the scale on
the right unless we already knew what to expect. The dB
scale makes the SLM actually readable.
Most sensory organs, including the ear, respond much
they
like the dB scale, i.e., / sense multiple or fractional
changes in the stimulus. For further discussion of the ear,
see Section 2 of Chapter 4.
The big disadvantage is that the scale is logarithmic
and not easily understandable from its mathematical definition.
This is not a handicap in ordinance enforcement, since one
gets an intuitive feel for sound levels very quickly, but it
is a handicap for the person charged with trying to explain
a proposed noise ordinance to his City Council. Figure 3-3
is the simplest solution for presentations that we can think
of at the present time.
3.5 Sound Pressure Levels vs. deciRels (Key Official, Sec. 3.2.32,
Articles VIII & IX, Chapter
3.5.i Definition of Sound Pressure Level
Figure 3-4 shows the basic operation of a sound level
-------
0
9
8
7
6
5
4
3
2
1
10 .
el
>cali
ale
10,000,000,000=1010
1 ,000,000,000= 109
100,000,000= 108
10,000,000=107
1 ,000,000=106
100,000=105
10,000=104
1,000=103
100=102
10=10^
1=10°
Actual Number Scale
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0.
SPL
I 200
20
20 X 10"1
20 X 10
-2
20 X 10'3
-4
20 X 10
20 X 10"5
Threshold of paiii
Pneumatic chippers
Rock music
Jet aircraft near airport
Urban traffic
Threshold of Hearing Loss
Threshold of Speech Interference
Business
Threshold of Sleep Interference
Broadcasting Studio
-20 X 10"6 Pascal Threshold of Hearing
RMS Sound
Pressure
Typical Levels
A-weighting
(b) The Soum" Pressure Level Scale
Figure 3-3
-------
3-15
meter, one stage of which is the conversion of
the linear to dB scale . and
the words we use to describe the change from "sound
pressure" to sound pressure level. The addition.of the
word "level" implies that the dB scale has been used and,
strictly speaking, it is redundant to say: "The sound
pressure level is 70 dB." Common usage, however, is to
say it this way.
In order to make the numbers we use in measuring
sound of practical size, we have set the lowest sound
pressure we can hear as the reference sound pressure,
which is ?0 microPascals. Referring to Figure 3-3,
we see that if the actual sound pressure is divided by
the reference sound pressure their quotient is one when
they are equal and so the deciBel scale reads zero. All
~
sound levels in environmental noise are greater than this.
In mathematical form, we define Sound Pressure Level (SPL) as:
SPL = 10 LOG
10
P
rms
P
reference
2
= 20 LOG
10 1 P
(reference)
Conversion reference level
to dB scale set
*Sound pressure level is defined as 10 times the logarithm
Fo the base 10 of the ratio of the mean square sound pressure
to the square of the reference pressure. It is also equivalent
to define it as 20 times the logarithm to the base 10 of the
root-mean-square sound pressure to the reference pressure
(See Section 3.2.32 of Chapter 7).
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3-16
The power of two appearing 1n the above expression has to
flo with how the average sound pressure is obtained in the
meter. From this expression we calculate the SPL scale
shown in Figure 3-3. In that fiqure, 0 dB represents the
threshold of hearing for normal people. When the sound
energy is 10,000 times greater than the threshold of
hearing (40 dB is 10^ greater than 0 dB) the threshold of
sleep interference approximately begins (See Section 4 of
Chapter 4). Above 60 dB interference with conversational
speech begins and above 70 dB, constant long-term exposure
will begin to cause permanent hearing loss in a small per-
centage of listeners (See Section 2 and 3 of Chapter 4 for
detailed discussion). Ear pain begins near 130 dB; this is
10 million million times (10^) more sound energy than that
at the hearing threshold.
3.5.2 Addition of Unrelated Sounds
A typical problem in the measurement of sound is in
the addition of sounds. Because the normal addition process
is converted to a dB scale, 2 dB + 2 d0 does not equal 4 dB.
Normally, the sounds to be added are not acoustically related
to one another so the following procedure applies. Only if
the two signals are acoustically identical, such as that from
-------
3-17
two loudspeakers with the same inputs, does this procedure
break down. In environmental noise we know of no case where
the procedure below does not work.
To add two sounds, consider one to be the reference
sound. We need only know the difference between the additive
sound level and the reference sound level get their sum from
Figure 3-5a. When the reference sound level and the total
are
sound level / known, we use Figure 3-5b.
Example Problem 1: We have a background sound level that is
46 dBA and a planned factory is predicted to make 50 dBA at the
nearest residential property. What is the predicted total noise?
Additive Sound Level = 50
Reference Sound Level =46
Additive - Reference = 4
Figure 3-5a: Sum = AD + 1.5 = 51.5 dB
Example Problem 2: We wish to keep the total noise at a residential
property boundary at 60 dBA or below. The background is already at
54 dBA. How loud can a factory be and still not go over 60 dBA?
Total sound level = 60
Reference sound level = 54
Total - Reference = 6
Figure 3-5b: Additive:= REF + 5 = 59 dB
Rules of Thumb: 1. Eaual levels added: Total 3 dB greater
2. One level 10 dB greater than another :
Total is same as greater level
-------
16
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Ref - 2
1.5-' Ref - 4
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. 5 " Ref. - 9
0,. Ref. -12
(b)
Figure 3-5
-------
3-18
3.5.3 Subtraction of Unrelated Sounds
In many environmental noise enforcements, we wish to determine
the noise contribution from a potential violator, but the background
noise may cause interference, i.e., the SLM is measuring whatever it
hears, which is the sum of both noises. We wish to subtract away the
background noise to get the contribution from the possible violator.
Figure 3-5b can be used for this purpose.
Example Problem 3: A commercial establishment was measured to give
63 dBA at a residential property line durinq the day. It was possible
to shut down the noise source at that establishment so that the back-
ground noise could be measured. It was found to be 57 dBA. Is the
establishment in violation of the 60 dBA limit?
Total Sound Level = 63
Reference (Background) Sound Leve1=55
Total - Reference = 8
Figure 3-B: Additive Level = REF + 7 = 55+7 = 62 dB
Conclusion: Establishment is in violation.
3.6 Frequency Weighting of Sound Pressure Levels (Key Official; Sec. 3.2.1, Chap 7)
As noted earlier, there is only a limited reason for measuring the
magnitude of sounds outside the range of human hearing. Thus, most SLM's
have a frequency range that is limited to the audio range. Before any sound
gets to the frequency weighting network (see Fig. 3-4) it must pass through
the microphone. Most microphones can accept a broader range of frequencies
than is necessary for noise ordinance enforcement so they do not limit the
-------
3-19
ability of the SLM.
We have drawn Figure 3-6 to compare the ability of the human ear to
hear various frequencies with the ability of the SLM frequency weighting
networks to process various frequencies. The reference frequency for the
curves is 1000 Hz. We can see the relative response of the ear to either
pure tones or random sound at environmental noise levels is not a smooth
curvej especially near 4000 Hz where the ear canal has a resonance that
amplifies the sound in that frequency range. Almost all SIM's have
frequency weighting networks marked A, B, and C. The frequency response
of the SLM for those weightings are shown in Figure 3-6 and none closely
match the ear response. A D-scale has been developed which more closely
approximates the ear response curve to random sound but it 1s not yet 1n
widespread use. Historical development in relating human response to noise
has led to use of the A scale or dBA dB(A) and the correlation between
dB(A) and complaints has been sufficiently established to warrant its use
over dB(B) or dB(C). There are other, more sophisticated, measures, such
as octave bands, which require more than one number (or measurement) to
specify them and consequently are an enforcement headache and are not
recommended. Consequently, all sound descriptions in Chapter 7 are denoted
as dBA, to show that the A-weighting network of the SLM is used.
When the weighting networks are used, it is common to use the expression
"sound level" as opposed to "sound pressure level" to indicate that the
entire range of frequencies is not processed uniformly.
-------
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£ 3 4 5 0 7 8 9 7 2 3 4 5 9 7 8 9 1 2 3 <66 7 8 9 1 t
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FREQUENCY IN CYCLES PER SECOND
FIGURE 3-6
-------
3-20
3.7 Fluctuating Sounds (Key Official; Article VIII & XI, Chapter 7)
3.7.1 Why Measure Fluctuating Sounds?
Everything we have discussed to this point has presumed that
we have been able to determine a sound level from the meter. Five
minutes exposure to SLM use will convince the user that the sound
level is almost never the same, and the question arises: What SLM
reading do we use to describe the situation? We must learn how to
handle fluctuating sounds in a noise ordinance for the following
reasons.
The temptation in ordinance enforcement is to record the highest
SLM reading found and use that as the number to compare with the
ordinance limits. It simplifies enforcement but it may not be accurate
or reasonable, so a balance may be required. For example, the yell of
a child or the pass of a lawnmower may produce a short but loud sound
level. Should it be made illegal or should some allowance be made for
the duration of that loud noise? In large communities with enforcement
problems there is a tendency to use the maximum reading for all noise
sources and use discretion in enforcement; in smaller communities there
is, and has been, a tendency to permit brief sounds to be louder.
The response of people is more highly negative to intrusive sounds,
those that create sound levels well above the background sound level.
The dripping faucet is the classical example of a very low level but
very intrusive and annoying sound. The same occurs with a huge garbage
-------
3-21
collection truck passing by on a relatively quiet residential street.
Thus, we need to discuss means for describing the intrusiveness
of sound, particularly those that are transient in nature. One result
of the discussion will be a definition for ambient or background sound
level.
3.7.2 Measuring Fluctuating Sounds
When fluctuating sounds are measured, the frequency weighting
is almost universally that of the A-weighting so the SLM should be set
to that position.
There are three practical ways to measure fluctuating sounds.
The simplest and least accurate is to observe the sound level meter.
By setting the SLM on a high scale, you will occasionally observe a
high sound level which represents the loudest sounds made. Similarly,
by setting the SLM on a low scale, you will occasionally observe a
low level which represents the minimum sound levels. From this you
can get a reasonable estimate of where the range of fluctuating sounds
fall on the dB scale. Certainly if the minimum sound level is above
that prescribed by an ordinance, there is no need to go further in
the measurement process. The second and third methods are more
complex and are considerably more accurate. The second is to read
the SLM at uniform increments of time and record the numbers read
on a sheet of paper. The third is to feed the SLM output (AC or
-------
3-22
DC depending on the receiver instrument) to a graphic level
recorder which records a time trace of the sound on a piece of
paper (See Fig. 3-4).
In the second method, the measurer stands at the point of
interest with the ?LM and perhaps a stopwatch, and reads and
records the sound level read at fixed time intervals. If he
wishes to characterize a continuous noise source such as a free-
way on an hourly basis, he needs to take about a 20-minute sample.
If he reads the SLM every five seconds then he'11 get 12 x 20 = 240
sound level readings which he can further process as discussed below.
There are several severe limitations on the method, although it re-
quires the simplest equipment. The major limitation is that most
simple SLM's have at most a 15 dBA range in the window of the meter
and most environmental noises vary more than that so some of the
time the meter is off scale. By judiciously setting the meter
scale either high or low, the data lost can be either at the high
or low end. Thus, by making two 29-minute samples it may be
possible to get useful data. Another limitation is that most
SLM's do not have lights, so it is necessary in the evening to
juggle a flashlight, SLM, stopwatch and pencil and paper (in the rain?)
simultaneously, it is enough of a hassle that the third method is
more practical. It is possible to use the second method near free-
ways and arrive at some traffic noise data, but it is awkward for
-------
3-23
fluctuating stationary noise sources.
In the third method, the signal 1s fed to a graphic level recorder.
The recorder has a damping characteristic so the dBA vs. time trace
does not fluctuate too rapidly, i.e., if the needle fluctuates so
rapidly you have to concentrate to see it moving, it is too fast a
response. The SLM has only a "Fast" and "Slow" setting, while recorders
have several. The recorder can accommodate a broader range of sound
levels and they are now battery powered. The calibration signal and
the trace are printed on paper so you can drink coffee while it is
happening. The SLM can be in the rain or cold and the recorder can
be Inside where it can be seen. To get the table of numbers, one
later reads the sound level where the trace crosses the vertical time
marks (the recorder speed determines the time separation of those
marks). A sample of an actual trace is given in Figure 3-7. Because
the paper speed was 2.5 inches/minute, each 1/4 inch division was six
seconds of time. The dB(A) values were picked off at six-second in-
tervals to the nearest whole number. We got ten numbers per minute
in this case, so 1n 20 minutes we have 200 samples. In the next
section we will do something with those numbers.
-------
3-24
3.7.3 Histograms
This material is tutorial, to lead up to the discussion in
the next section on cumulative distributions. Ordinarily, histograms
are not needed in noise ordinance enforcement.
If we tabulate the number of times a particular sound level
was observed we might get a table such as shown in Table 3-1, where
the range of sound levels was between 45 and 80 dB(A). A histogram
can be made of these observations. If n. is the number of observations
i
at any dB(A) and the % of the total occurrence is n] x 100/243, then
the histogram is the percent of the total time that any particular
sound level was observed to occur. The check marks in Table 3-1 are
a form of histogram, but Figure 3-8 shows a more accurate graph which
gives the percent of the time a certain sound level occurs. The
figure should make it clear that community sound levels are nowhere
near constant and that they fluctuate over a very broad range of
levels. For the case shown in the Figure, we see that most of the
time the levels are below 55 dB(A) with 50 dB(A) occurring most often.
How do we define the ambient or background level? The American National
Standards Institute (ANSI) document SI.1-1960 (R 1971) defines ambient
noise as ... "the al1-encompassing noise associated with a given
environment, usually being a composite of sounds from many sources
near and far." Since the measurement made to make Figure 3-8 fitted
that definition, the ambient is described by the set of 34 numbers
-------
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CO
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-------
u_
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
Histogram
0ata niXlOO
Distribution
Data
(dba)
Mar'.s
U-
251
i
m
ii
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444+
1111
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wu n
4444- 444+
4444- 4414
4444- 44-;+ 1
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444+ 4+1+ 44+1- 4+1-1 +H+ 1
4444- 4414- 444-1- 444+ 1111
++B- W+ .JJ4J. 444+ 444 1 444+
444+ +144—H4+ +B+ 4-14V 1-14+
4444- 1
4+4+ 44 H- +H+ 1 1
44+1-
11
1
0
0
0
0
0
1
0
1
1
0
1
I
1
2
4
3
7
¦ b
4
6
7
10
10
II
14
13
26
24
30
35
17
5
2
0
0
.41
0
0
0
0
0
.41
0
.41
.41
0
.41
.41
.41
.82
1.65
1.23
2.88
2.06
1.65
2.47
2.88
4.12
4.12
4.53
5.75
5.3b
10.7
9.88
12.35
14.C
7
2.06
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0
n
in -j XI00
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1
2
2
3
4
4
5
6
7
9
13
16
23
28
32
38
45
55
65
76
90
103
129
153
183
219
236
241
243
243
243
.41
.41
.41
.41
.41
.41
.82
.82
1.23
1.65
1.65
2.06
2.47
2.88
3.70
5.35
6.58
9.47
11.5
13.2
15.6
18.5
22.6
26.7
31.3
37.0
42.4
53.1
63.0
75.3
90.1
97.1
99.2
100
100
100
-------
IVC T I iAn • AL^ANCttE^
tiwttiv ft m« eo.
-------
3-25
in Table 3-1 . To reduce the amount of numbers required to describe
the sound environment, the cumulative distribution of the sound levels
is calculated as described below.
3.7.4 Cumulative Distributions - L (Article VIII, Chapter 7)
n
A cumulative distribution of sound levels is obtained by summing
up the percentage of time histogram to get the time a given sound level
is exceeded. For the example situation in Figure 3-8, 82 dB(A) is ex-
ceeded 0% of the time since the highest level observed was 80 dB(A),
while 45 dB(A) was exceeded 100% of the timo .vince the sound level
meter never got that low. Thus, a cumulative distribution sums up
the levels from the highest to the lowest and ranges between zero and
100%. Therefore, the cumulative distribution (Ln) is the A-weighted
sound level that is exceeded n percent of the measurement period. We
have done a sample calculation for the histogram in Figure 3-8 and the
results are shown in Table 3-1. In graphing these numbers, Probability
graph paper is often used, although it is not necessary. We show the
graph of the cumulative distribution in Figure 3-9. A line is faired
through the data points in the center range; at either extreme there are
so few samples that the validity of the data is questionable and dashed
lines are drawn. From this curve we can obtain what are called Ln values:
they are the sound levelr (L) that are exceeded n percent of the time.
Three of special importance are the Lgg, values, and as the n
-------
V A fS
-------
3-26
number pets smaller, the L value always gets greater. Thus, 90% of
the time the sound is greater than 50 dB(A) in our example and half
the time it is greater than 53 dB(A), and only 10% of the time is it
greater than 62 dB(A). At the measurement position we say that long-
term or chronic noise exposure is 50 dB(A) and the more acute noise
exposure is 62 dB(A). Those words must be qualified to apply to
cumulative distributions derived from data taken over many hours and
not 20 minutes.
Returning to the concept of ambient noise, we note that if a
continuous sound source is less than 50 dB(A) when it is added to
the existing sound, it will be effectively inaudible around 90% of
the time - but we cannot guarantee it will be inaudible all of the
time. So, if we define ambient noise as the sound level exceeded
90% of the time when the potentially unlawful source is excluded,
we will have a good reference for audibility. See Definition 7.2.2
in Chapter 7.
3.7.5 Equivalent Sound Level - Lgq (Article XI, Chapter 7)
This discussion is meant to lay groundwork for the discussion
in the next section. The measure discussed here is useful in its
own right for assessing the potential for hearing loss (See Section 2
of Chapter 4).
We have seen in the previous section that from the several
hundred (or even thousand) samples of sound levels obtained, we have
-------
3-27
ppocessed the data and reduced the number of descriptors of the
sound environment to one hundred (Lgg to LQ), from which we have
chosen only three (Lg0, L^, L ). For its regulatory work, the
U.S. Environmental Protection Agency has begun to use a one-number
descriptor of the environment called the Equivalent Sound Level (Leq)-
It is defined as the level of a steady continuous sound which would
contain the same sound energy as the actual fluctuating sound, i.e.,
1t 1s the fictitious sound level which has equivalent dnergy to the
actual. The mathematical definition and some discussion of this sound
descriptor is given 1n Reference 1. An appropriate formula for
calculating Leq from the sampling method given above is:
(See the list at the end of the chapter for an exact
mathematical formula)
For our example problem, the data given 1n Table 3-1 would result in
a summation like:
1
Leq " 10 '°9l0
Leq ¦ 61 dBA
243
^ x 104-5^ 0 x io4-6j+^
x 104-7 I +5x1
This calculation can be tedious if done by hand, with a slide rule or
simple calculator, but there are instruments now that process the
acoustical data automatically. Thus, using this descriptor 1n a
noise ordinance will require a certain level of funding to obtain
the necessary equipment.
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3-28
There 1s one way the L can be roughly approximated. Note
oq
that the value we obtained above 1s only 1 dB(A) below the
tenth percentile noise level shown in Figure 3-9. Generally,
L is within 2 dB(A) of L so a measurement of L„„ can give
eq lo 10
an approximate value of L .
How do we describe the sound environment over a 24-hour
period? We could simply extend the measurement period from one
hour to 24, but if the equipment was to malfunction during that
period we would have to start all over, so in practice we determine
'¦•eq ™ one_hour intervals. The descriptor discussed below 1s
currently being used for the purpose of 24-hour averages.
3.7.6 Day-Night Average Sound Level - (Article XI, Chapter 7)
This descriptor of sound is useful for planning but not
enforcement since it is too much of an average to apply to the
specific problems encountered in t.he direct enforcement of noise
ordinances. Since Section XI of Chapter 7 concerns rioise prevention
planning, this discussion is useful if you are contemplating
incorporating that section.
In order to describe the sound environment over a 24-hour
period with only one number, we need tc find a means of properly
adding up each of the hourly L values. We can do this also on
eq
an equal energy basis to get what we call L (2<5). To best
" M
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3-29
relate to human response (Ref. 1) It has been found that,
because people are more annoyed at night by a given sound
than 1n the day, the levels measured between 10 p.m. and
7 a.m. should be penalized by 10 dB(A) so they will have
more like "equal annoyance" values.
The formula for calculating L. from hourly data 1s
dn
Ldn = 10 log10
1 / 10pm . 7am .
iT i 1°L«1 + £ 10^eg+_l()
I I 7pm 10pm 15 i
ie 15 daytime L values and the second
eq
The first sum 1s of t
sum 1s of the nine nighttime values augmented by 10 dB(A).
Considering an example problem, Table 3-2 gives a tabulation
of 24 values calculated for a typical workday. We note
that the previous example was for the 4 to 5 p.m. period
where we obtained Leq = 61 dB(A). Calculating we get a
sum like
Ldn = 10910 ATj"^05-s+10S-9+106-°+...J + |
6.9 6.4 f
10 +10 +10
Ldn " 61
A graph of the Leq values is shown in Figure 3-10 along
with the Lj value. We can see from that Figure that even
dn
though that location became quieter at night, it did not begin
early enough, so the 10 p.m. to 1 a.m. noise made the Ldn
number higher than 1t would have been if the noise had decreased
-------
Hour
Leq
Leq
+ 10
7- 8 a.m.
59
8- 9
59
9-10
60
10-11
58
11-12 noon
61
12- 1 p.m.
61
1- 2
2- 3
60
59
Day
3- 4
58
4- 5
61
5- 6
60
6- 7
58
1
00
56
8- 9
55
9-10
62
10-11
59
69
11-12 midnight
54
64
12- 1 a.m.
53
63
1- 2
48
58
2- 3
3- 4
45
45
55
55
Ni ght
4- 5
45
55
5- 6
49
59
6- 7 a.m.
55
65
Table 3-2
Table of Leq values in typical community
-------
10 X to TO THE CENTIMETER 46 1510
OX CM I., •) :- »
KEurrEi a csser co.
-------
3-30
sooner. One may be tempted to use L . as a sensitive
an
measure of night noise for noise ordinance purposes.
Suppose a time limit was imposed in an ordinance (See
Discussion Section B of Article VIII in Chapter 7) so
that the hypothetical Leq data shown in Figure 3-10
were obtained instead. The Ldn value would become 58.5,
a reduction of slightly over 2 dB(A). The change is a
small but significant reduction, so in spite of the
fact that it is small, it does give us a one-number
descriptor of the sound environment.
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3-31
References
1. Information on Levels of Environmental Noise
Requisite to Protect Public Health and Welfare
with an Adequate Margin of Safety U.S.
Environmental Protection Agency Document
550/9-74-004. March 1974.
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3-32
REFERENCE LIST OF DEFINITIONS AND IMPORTANT TERMS
Wote: In some places two definitions are given. They are scientifically
the same, but our wording is intended for noise ordinances.
The sections shown in the list relate to those 1n this chapter.
DECIBEL (ANSI Sl.l - 1960)
The decibel is a unit of level where the
base of the logarithm is the tenth root of
ten, and the quantities concerned are
proportional to power.
(CHAPTER 7) A logarithmic (dimensionless) unit of measure
often used in describing the amplitude of sound.
Decibel is denoted as dB.
dB = 10 LOG^ X) where X is some power quantity
HERTZ
Section 3U5
The word used to describe the frequency of a sound.
It 1s identical to cycles per second.
SOUND PRESSURE
Section 3.3
The instantaneous difference between the actual pressure
and the average,static or barometric pressure at a given
point in space.
/> = f>U)
pressure is a function of time
MEAN SQUARE SOUND PRESSURE
Section 3.3
The average over a specified period of time
of the square of the sound pressure
i
/>* - 7" J
T is 1 second or less
RMS (ROOT-MEAN-SQUARE) SOUND PRESSURE
Section 3.3 (ANSI Sl.l - 1960)
The RMS sound pressure at a point 1s
the root-mean-square value of the
instantaneous sound pressure over a
time interval at the point under
consideration.
-------
3-33
(Chapter 7) The square root of the time averaged square
of the sound pressure, denoted P
rms
rms
SOUND PRESSURE LEVEL.
Section 3.5
(ANSI Sl.l
\J
j f
I960) - The sound pressure level,
1n deciBels, of a sound
is 20 times the logarithm
to the base 10 of the ratio
of the RMS sound pressure to
the reference pressure
which shall be 20 micro pascals,
and is denoted L or SPL
L » 20 I'M.../ijr>"A = 10 LOG
p 10lftrf/ 10
A-weighted sound level means the sound pressure
level as measured on a sound level meter using
the A-weight1ng network. The level so read
shall be designated dB(A) or dBA.
A-WEIGHTED SOUND leve£
Section 3.6
Lfl = 10 LOG
A 10
PX
' A
p1 f
' rtT
Nth PERCENTILE LEVEL - The A-weighted sound level that is exceeded
Section 3.7 N percent of the time in any measurement period,
-------
3-34
EQUIVALENT SOUND LEVEL - The level of a steady A-we1ghted sound
Section 3.7 that has equivalent sound energy to the
actual time-varying A-weighted sound
during the same period.
L = 10 LOG
ec) 10
T is now 1 to 24 hours
61
DAY-NIGHT SOUND LEVEL
Section 3.7
The equivalent sound level during a 24-hour
time period with 10 decibels added to the
equivalent sound level during the night time
hours of 10 p.m. to 7 a.m.
If the L _ is divided into 1 hour increments then
r~ / top* Uq 7** fa
Ldn = 10L0GW^( £10^+
L~ 7*ni top*
PURE TONE (ANSI Sl.l - 1960) A simple (pure) tone is a sound wave,
Section 3.6 the Instantaneous sound pressure of
which is a simple sinusoidol function
of time.
(Chapter 7) See Section 3.2.26 of Chapter 7
IMPULSIVE SOUND - A sound containing excursions, usually less than
Section 3.1 one second, of sound pressure level 20 dBA or more,
over the ambient sound level, using the "fast" meter
characteristic (see Chapter 7 for two alternative
definitions)
-------
CHAPTER 4
NOISE EFFECTS ON HEALTH AND WELFARE:
THE REASONS FOR NOISE CONTROL
This chapteA pAesents Information on the effects of noise on people
and may be used to: (J) determine a community's very Important "health
and wtelfare goals," (2) determine the. needs and, If such exists,
support the justification for a noise ordinance and noise control
program, and (3) provide Information for a noise education pAogram
designed to alert citizens to some of the deleterious effects of
noise they may not be wojie 0|$ but can avoid. The noise effejcts
which. are. ph.ese.nte.d In layman terminology aAe: hearing loss, speech
InteAfeAence, sleep inteAfeAence, annoyance, educational AetaAdatlon,
peAformance loss, and other, physiological and psychological, effects.
The chapteA shorn that permanent hearing loss can occua with chronic
exposure, to noise levels above 70 db(A) and speech InteAfeAence
problems typically begin avove 50 db{A), while sleep inteAfeAence
and annoyance may occua at any audible noise level.
Intended Readership: The individual assigned the responsibility
of determining and supporting the health
and welfare goals of the community's noise
control program and other individuals
interested in the effects of noise on people.
4-1
-------
4-2
1. INTRODUCTION
The two main purposes of this chapter are:
A. To provide an understanding of the effects of noise on
people which will .enable you to recommend a list
your
of health and welfare goals for community's noise
control program that will satisfy long-
range needs.
B. To provide information on the effects of noise which can
be used in the educational portion of your community's
noise control program that is designed to alert your
citizens to some of the deleterious effects of noise
they may not be aware of but can avoid.
The major effects of noise on us are listed in Figure 4.1. and
are separately discussed in the later sections of this chapter.
Of these effects, the most is known about hearing loss, speech
interference, and sleep interference, and each of these effects
can be minimized by improving your noise environment. However,
in the future, the noise effects requiring the greatest attention
may be annoyance, loss of performance, and the more psychologically
based effects.
Most people do not become concerned about hearing loss until
it's too late. These days, in typical communities, it is necessary
for us to exercise some control over our individual noise exposure
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4-3
1. Hearinn loss
2. Speech interference
3. Sleep interference
4. Other physiological effects
pain
(b) vertigo
(c) blood vessel constriction
(d) blood pressure increase
(e) heart rate increase
(f) paling of mucuous membranes
(g) increaseed hormone production
(h) orienting and startle reflexes
(i) internal organ rupture
5. Annoyance
6. Other psychological effects
7. Educational retardation
8. Performance loss
Figure 4.1. Primary Deleterious Effects Of Noise On People
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4-4
1n order to protect, our hearinq from permanent hearing loss. Speech
Interference 1s a fairly obvious Interruption of communications
resulting from excessive background noise. In most cases communica-
tion returns to normal as soon as the background noise is reduced.
However, more lasting problems can result for young children still
developing significant portions of their vocabulary and knowledge
base. The very interesting and complex effects which noise can
have on our sleep patterns are very subtle. The affected Individual
is often not aware that noise is responsible for the poor quality
of his rest. Fortunately, most of the other physiological effects
of noise, although rather surprising, are not common causes of concern
in the typical community environment, with the possible exception
of startle reflexes. Annoyance is the big one. It is probably
the reason you are reading this chapter now. Most conmunities initiate
noise control programs as a result of noise-induced annoyance.
Since annoyance varies considerably with the sensitivities of the
receiving individual and the characteristics of the particular
noise source, annoyance is difficult to quantify with solid cause
and effect relationships. Fortunately, most conmunities find
that a noise ordinance numerically based on the data provided in
this chapter from the effects of hearing loss, speech interference
and sleep interference provide sufficient control to eliminate most
annoyance problems, particularly if the enforcement officials have
a good understanding of all of the effects of noise on people.
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4-5a
The other psychological effects are not yet as well understood.
Educational retardation and performance loss may become a problem
when any of the other effects are present. Any deleterious effect
of noise on us is capable of reducing our performance, particularly
that of young children in the classroom.
Before proceeding with the remainder of Chapter 4, the reader
should make sure he has an understanding of the following terms,
which are outlined, discussed, and summarized in Chapter 3:
Sound
Frequency
Hertz (Hz)
Sound Pressure
Sound Pressure Level (Ln)
Decibel (dB) v
A-Weighted Sound Pressure Level LA 1n units of dB(A)
Equivalent Sound Level (L )
Day-N1ght Equivalent SouncTLevel (Ldn)
Impulsive Sound
Each of the following sections discusses the above noise effects
and are intended to give you an understanding of how and under what
conditions noise can cause those effects and what noise levels are re-
quired to protect individuals from those effects. At the close of each
section, a health and welfare goal is suggested for your consideration
should that particular noise effect be now, or have a potential of be-
coming, a problem in your community. Also summarized there are the
various numerical criteria for the noise levels currently believed to
be required in order to eliminate varying degrees of that particular
noise effect. For instance, an example from the hearing loss section
Indicates that if hearing loss is now or could become a problem in the
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4-5b
future you might consider recommending a goal and associated
criteria similar to the following:
H&W Goal: To prevent noise-induced permanent hearing loss
throughout the entire frequency range of hearing.
Current Criteria: 1) Average continuous all-day sound
pressure level exposure should
be less than 70 dB(A)
2) l_eq (24) less than 70 dB(A)
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4-6
3) Leq(g) less than 75dR(A)
4) Impulse noises not to exceed the modified
CHABA limits for peak sound pressure levels.
Your main job 1s to recommend a list of health and welfare goals
for your community. Steps 4-7 of the procedures of Chapter 2 are
designed to help you do this. You may find it helpful to place
copies of figures 2.2 and 2,3 in a visible location for reference
as you proceed. The following sections of this chapter should
provide you with sufficient understanding to determine which
noise effects are now a problem in your community or could become so
in the future. As discussed in Chapter 2 (steps 4 and 5) the
complaints received by the community, the results of the attitudinal
survey, and noise measurements madein the community in suspected
problem areas will aid you in this task. After selecting those
suspected problem areas from the noise effects list in Figure 4.1
you may then compose a list of health and welfare goals to be
recommended by you for approval of the proper authorities in Step 8.
Section 10 of this chapter summarizes the recommended health and
welfare goals and the associated numerical criteria for each of
the effects discussed.
He believe very strongly that a list of health andWpi^ar«- goals
are important 1n order to initiate a successful noise control
program for the following reasons:
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4-7
1. As discussed in detail in Chapter 7, the only feasible legal
basis for the community's right to control noise is based on the
health and welfare effects of noise.
Therefore, if you can show that your initial noise
ordinance and your subsequent noise control program is based
on health and welfare goals and needs, your efforts will
have a sound legal basis.
2. It is easier to uphold the constitutionality of your ordinance
in a court of law if you can show that it is based on health
and welfare goals supported by the current numerical criteria.
It should be noted that the numerical criteria should
not be included in the H & W goals approved by your city
council. The opportunity should remain for later updating
of the criteria as more data becomes available from
ongoing research. The authors believe history will continue
to show that future research will indicate that more strinn*nt
noise control is required, rather than less.
3. The health and welfare goals provide very quickly a common point
of agreement hetween advocates of a noise control ordinance,
potential noise violators and community authorities.
Our experience indicates that it is relatively
easy to get Deople to agree, for instance, that permanent
hearing loss induced by noise is a had thing and that
one ought to be able to carry on a conversation with his
children in his own living room without noise interfering
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4-R
with that conrnunication. Agreement on health and welfare
goals then provides a common point of agreement.
Then the deliberations and numerical content of the initial
noise ordinance can more properly be based on a comparison
of: (1) the economic and social feasibility of achieving
initially a certain level of noise control with {?.) the
desired elimination of deleterious noise effects. Your
community may already be quiet enouqh to accomplish
the goals you select. If so, you are indeed fortunate
and the task then is to preserve what it has by adopting
standards that will maintain the current level of quiet
in the future. However, most communities will find it
necessary to reduce their current noise levels 1n order
to achieve the desired results. Then it may be necessary
to carefully consider the economic effects for your
coimuinlty in reaching these goals. You will have to
ask yourselves "what are the consequences of not achieving
our goal, as compared to the economic, cultural, and social
consequences of realizing our objective too fast?" At any
rate, a program of noise control should be laid out by
your community which will achieve the qoals in a reasonable
period of time even if it must be done in several steps,
keeping 1n mind that consumer and operator awareness of
noise effects and U.S. EPA standards for manufacturers
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4-9
of noisy products will help reduce noise levels.
4. The real objective for a noise control program is, in fact,
to eliminate and prevent deleterious effects of noise on
the receivers of that noise.
Some communities, forget that. For instance,
a typical example is a community whose noise control
program was initiated as a result of annoyance from motor-
cycle noise. It seems to be very tempting to launch a
noise control program which is primarily designed to harass
and otherwise eliminate all motorcycle operators. When,
in fact, most communities find that a small percentage of
motorcycles operators are responsible for the annoyance
and once that percentage is placed under control the need
for continuing enforcement of motorcycles is eliminated.
The goal of a community's noise control program should be
in order
to achieve quiet where quiet is required/to eliminate
deleterious health effects and not to harass the public,
raise money for the community coffers, etc.
5. Having a list of health and welfare goals with the associated updated
criteria will allow a proper mechanism for a community to later
evaluate the effectiveness of its noise control program and suggest
improvements in order to achieve those goals.
6. Later improvements in the noise ordinance are easier when city
council members are initially aware that achievement of the
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4-10
health and welfare goals 1s the real objective of the program
and the first ordinance may not be adequate.
It 1s easy for community authorities to pass a good,
initial noise control ordinance and assume that that ordinance
1s capable fo solving the community's noise control problems
forever. If instead -the city authorities approve a list of
health and welfare goals and launch an initial program the
first step of which is the initial ordinance and its
administration which is designed to achieve that goal it
will be easier to later modify the program as such needs become
apparent.
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4-11
2. HEARING LOSS
(a) Occupational Noise Exposure
Noise-induced hearing loss has long been recognized as an
occupational hazard. Recent amendments to the Walsh-Healey
Public Contracts Act (1969) specified noise limits which purport
to safeguard the hearing (for speech) of a certain percentage of
employees. This has now been replaced for most occupations with
standards (Figure 4.2) regulate the permissible noise levels and
durations during a working day. These standards were determined
from studies of occupational hearing loss. Since that time, con-
siderable audiometric data has been collected which continues to
confirm the hearing loss induced by occupational noise sources.
Further, the initial level of 90 dBA for 8 hours was a com-
promise based on the difficulty of irmiediate achievement in some
types of industries, and there are under consideration, by the
Department of Labor, steps which will gradually tighten these
limits.
The intent of the OSHA standards is to protect only that
portion of hearing acuity believed necessary for understanding
"normal" speech. Some studies indicate that speech intelli-
gibility is reasonably well-preserved if hearing is intact through
2,000 Hz, (cycles per second). However, these studies were based
on 1) ideal listening conditions with 2) no background noise or
other interference and 3) ideal familiarity with the vocabulary
the Occupational Safety and Health Act/
(1971, P.L. 91-5
/ These
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4-12
Exposure Time
15 minutes or less
1/2 hour
1 hour
2 hours
4 hours
8 hours
Sound Pressure Level
115 dB(A)
110 dB(A)
105 dB(A)
100 dB(A)
95 dB(A)
90 dB(A)
Figure 4.2 Maximum Daily Occupational Noise Exposure Allowed
by U. S. Occupational Safety and Health Act (1971)
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4-13
as well as 4) high motivation; conditions which do not always
apply in more "normal" speaking-listening situations. The
determination of "hearing impairment" might thus be more re-
strictive than most of us might accept if it were our hearing
that was being judged. So the OSHA standards are limited in the
protection they provide in at least the following respects:
1. They protect only 85-90% of the employees whose noise
exposure is within the limits. In other words, 10-15%
noise
of the workers experience / conditions rated as safe
by this standard will still suffer some permanent hear-
ing impairment after a working lifetime of exposure.
2. They do not classify an individual's hearing as im-
paired until he has permanently lost at least 25
decibels of hearing at the frequences of 500, 1,000 and
2,000 Hz.
3. They assume no significant exposure (nothing over 60
dBA) when the employee is not working (EPA Levels Document 1974).
4. Hearing loss (even total) in the higher frequencies,
(above 2,000 Hz) is not protected, in spite of the fact
that these are the frequencies most often affected by
noise exposure. Our ears are originally capable of
hearing through the frequency range of 20-20,000 Hz.
We know now that in the presence of noise, one must have
normal hearing up to 4,000 Hz in order to properly under-
stand speech (Figure 4.3). The contribution of the
higher frequencies to the quality of life, in terms of
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4-14
enjoying music or theather, or the sounds of nature 1s
not accounted for at all.
There is much controversy that, even for the Intended pur-
poses, the OSHA standards are not strict enough. Some con-
sideration is being given to reducing the 8 hour exposure limit
from 90 dBA to 85 dBA, although apparently not for some time.
(b) Non-occupational Noise Exposure
The OSHA standards have Implicitly assumed that an Individual's
noise exposure is very minimal (less than 60 dB(A) during the non-
working portion of the day. Unfortunately, in both our urban
communities and rural areas this is no longer the case. In order
to protect our hearing, it is now necessary to consider the off-
job noise conditions as well. The U. S. Department of Health,
Education and Welfare, the Public Health Service, and the Environ-
mental Protection Agency have proposed non-occupational noise
4.3b)
standards (Figure which allow 16-24 hours of exposure to a
maximum of 70 dB(A).
Part of the support for this daily exposure standard comes
from recent evidence that it is possible to suffer a temporary
hearing loss with 24 hour exposures to noise levels as low as
50-75 dB(A). The more convincing of these sets of data indicate
temporary hearing loss from a 16 hour daily exposure to 65-75 dB(A).
In reality, most of us are not continuously exposed to more than 70
dB(A) for 16 hours a day. However, we are periodically exposed
to noise levels far in excess of 70 dB(A). If we choose 70 dB(A)
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4-15
FREQUENCY m Herli
Figure 4.3 The Speech Area indicating the Frequency Range
Important for Understanding Speech
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4-16
Exposure Time Sound Pressure Level
Less than 2 minutes
115
dB (A)
4 minutes
110
dB(A)
8 minutes
105
dB(A)
15 minutes
100
dB(A)
1/2 hour
95
dB (A)
1 hour
90
dB (A)
2 hours
85
dB (A)
4 hours
80
dB (A)
8 hours
75
dB (A)
16-24 hours
70
Q.
CO
Figure 4.3b Maximum Daily Non-occupational Noise Exposure
Recormiended by U. S. Department of Health, Edu-
cation, and Welfare, the Public Health Service,
and the U. S. Environmental Protection Agency.
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4-17
as the threshold for potential hearing loss, then in order to
protect our hearing during our lifetime, it is necessary to
spend a much larger amount of time exposed to noise levels
below 70 dB(A) than we spend being exposed to levels above
70 dB(A). How much is not accurately known. Individual dif-
ferences between peoples' susceptibility to hearing loss may be
the major factor in making accurate predictions.
The quality of our noise environment should at least pre-
serve our hearing, if nothing else. This suggests our all-day
(EPA Levels Document,
noise exposure should be less than 70 dB(A) or its equivalent. 1974).
Most communities now have noise levels in excess of this minimum
threshold for potential hearing loss. We recommend you include
a hearing loss prevention goal in your list of Health and Welfare
goals for your noise control program.
(c) Mechanism of Hearing Loss
Noise-induced hearing loss is usually related to the de-
struction or weakening of microscopic hair cells within the inner
ear. This destruction results in permanent hearing loss which
cannot be repaired medically or surgically. The mechanism of
hearing, considerably simplified, is as follows: A sound wave
picked up by the outer ear strikes the eardrum which vibrates
accordingly, causing 3 tiny bones in the middle ear, commonly
referred to as the hammer, anvil, and stirrup, to pass along the
sound wave to a fluid-filled tube in the inner ear known as the
cochlea, presumably because of its coiled shape. The tube con-
tains some 30,000 hair fibers which respond to the sound waves
-------
4-18
passing through, and depending on where they are located, allow
us to discriminate between different frequencies and intensities
of sound. As these hair fibers respond to the sound wave, a
signal is sent through a nerve fiber to the brain.
If the sound is extremely loud - say in excess of 120 dBA -
some of the hair fibers may respond so violently that they break
or are otherwise damaged. If the damage is temporary, that por-
tion of hearing served by the hair fibers may return to normal
after the loud sound is removed, but if they or their supporting
structures are broken, or otherwise permanently affected, that
portion of hearing is lost forever.
A more typical mechanism for hearing loss occurs when an
individual is subjected to sounds of moderate intensity (in
excess of 70 dB(A)) over a long period of time, which results in
a fatiguing of the hair cells causing them to become temporarily
inoperative. If the individual is healthy with a good blood
supply to the hair cells, they will recuperate later during a
rest period from noise and begin functioning properly again.
During this period, which may vary from a few seconds to several
days, the individual suffers a temporary hearing loss. If the
individual is repeatedly exposed to these noise levels for long
periods of time, particularly if the recovery "downtime" is
insufficient, permanent damange of the hair cells may result,
leaving the individual with a permanent hearing loss.
Normally this type of damage occurs so gradually that one may
not be aware of it until it's too late to adjust his sound
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4-19
environment in such a way as f.o preserve his hearing capability.
He usually first notices this hearing loss by his inability to
hear high frequency sounds, such as from cymbals, violins or
childrens voices.
As hearing loss of this type begins to occur, some sounds must
be louder for us to be able to hear them, thus our threshold of
a
hearing is raised. At the same time/phenomenon called recruitment
may occur whereby our pain threshold for sound is reduced. We are
not able to tolerate noises as loud as we used to. Therefore, as
hearing loss occurs we not only lose our frequency response but our
range of amplitude response as well.
The ear has several ingenious mechanisms to protect it from
excessive noise. One such mechanism, the middle ear or auditory
reflex, occurs when the brain receives an indication that the
sound is too loud, say in excess of 80 dB(A) and instructs the
muscles around the eardrum and the bones within the middle ear
to increase the tension on these parts, causing the signal amplitude
transmitted to the inner ear to be reduced. This mechanism affords
some protection to the hair cells but has some drawbacks: First,
the protective mechanism is not activated immediately but rather
takes about 15-40 milliseconds. During that time the ear is un-
protected and it is easy for permanent damange of the hair fibers
to occur, particularly if the noise is of impulsive nature such as
gunfire or firecracker explosions. Secondly, the protective
mechanism is not completely effective. It only serves to attenuate
loud continuous noises to a relatively less danger level. Thirdly,
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4-20
the protective mechanism itself fatigues in time with continued
exposure.
The responsibility for protecting one's hearing lies largely
with the individual himself. A community can, however, through
an effective noise control program, provide its people with the
opportunity to exercise that control.
(d) Individual Differences
There appear to be large differences between various individuals
acceptability to hearing loss and in their ability to recover from
temporary loss. Some peoples' ears are just more sensitive to
hearing damage than are others. And at this point there appears
to be no foolproof method of determining whether you will fall in
that particular class of sensitive individuals or not. It may not
have any relation to the amount of noise necessary to offend or
annoy us. Controlled experiments performed with guinea pigs, which
have ear mechanisms somewhat similar to humans, provide some in-
sights into individual difference effects. Lawrence subjected
guinea pigs to high noise levels for a period of 20 minutes and
then examined the recovery from the temporary hearing loss produced.
Sixty percent of the subjects regained their initial sensitivity,
10X regained none at all, and 30% continued to lose sensitivity
following the recovery period of 56 days. Later examination of
hair cell damage correlated with the recoveries mentioned.
In view of these differences and differing rates in which
hearing loss occurs in people because of their different noise
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4-21
exposures, it is difficult to establish what should constitute
"normal hearing" in present day mechanized society. Various
attempts have been made to define normal hearing loss as a
function of age, and hearing tests or audiograms may define an
individual's hearing loss relative to such "normal" hearing loss
curves. But it is by no means not clear whether hearing loss
as a function of age results for "normal" physiological deter-
ioration or from accumulated noise exposure. If it is the latter,
it presumably represents an injury to the auditory system that
could have been avoided, and should not therefore be included in
the calculation of hearing loss due to the aging process alone.
Individuals have been known to have one ear plugged with ear wax
throughout a significant portion of their lifetime to discover
the removal of the plug demonstrates a hearing capability in the
repaired ear comparable to that of a young child. Hearing tests
(Rose and Bergman, 1962)
have been made among certain natives in Africa/who have been
subjected to relatively low noise levels throughout their lives,
which illustrate very little difference between the hearing of
elderly natives and that of their yound children.
Audiometric testing of an individual's hearing does not
(Ulrich & Pinheiro, 1974)
always indicate hearing damage when hearing damage is present./ The
type of audiometric equipment and techniques used in the screening
of large numbers often lack the sensitivity necessary to measure
the details of hearing performance, particularly the perception
of speech and other complex auditory discrimination abilities.
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4-22
(e) Hearing Loss Among Children
Noise-induced hearing loss is now occuring among our children.
In Colorado, almost 3% of new voters have some noise-induced
hearing loss before they have an opportunity to cast their first
ballot. Since 1956, the Colorado Department of Health has had
a hearing conservation program designed to locate school age
children with hearing problems. A representative study of 1,000
children with hearing loss in 10 counties disclosed that 30% of
all hearing loss in children appeared to be the characteristic
(Weber, et al, 1967).
noise-related hearing loss/ . More recent Colorado studies
show what appears to be a noise-induced hearing loss among
younger children, including preschoolers, which is born out in
other wo^ by Marston, et.al. (1974).
Our young people are being exposed to rock music with peak
sound pressure levels in excess of the 115 dB(A) level for which
the U. S. Public Health Service reconmends less than a two minute
exposure each day if normal hearing is to be preserved. Apparently,
noise-induced hearing loss among children is sometimes also a result
of exposure to loud impulsive noises such as gunfire and firecracker
explosions. (Weber, et al, 1967).
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4-23
3. SPEECH INTERFERENCE
(a) Introduction
Science has a better understanding of the effect of background
noise on speech communication than most of the other noise effects.
And it is fairly easy to-comprehend. We are unable to understand
someone who is talking to us if the background noise is too loud
especially if the frequencies comprising the background noise are
similar to the frequencies in the speech we are listening to. This
is called speech interference, but the same problem can occur with
any sound we wish to hear. We may not be able to hear music, a
warning signal, or a bird singing if an airplane flies over, a
motorcycle passes by, or a neighbor's television is too loud.
The ability of background noise to interfere with speech com-
munication depends on several factors; the level of the noise, the
frequency distribution of the noise, the degree of understanding
the listener has of the speech material being presented, and the
predictability of the message.
Some industrial workers can conmunicate with each other amid
very loud background noise because they have learned to anticipate
routine communications, or "read" the message from facial expressions,
gestures, and Hp movements. Such a worker may have difficulty
understanding unexpected or non-routine messages.
Very young children may have an additional problem - they
gradually deduce their knowledge of language and its subleties
-------
4-23a
x
o
X
<
CD
"O
UJ
CO
o
z
o
z
3
o
cr
o
*
o
<
CO
5
o
120
110
100
90
80
70
60
50
40
L o_i. ¦ i I i i i » i ' ¦ ' ' I ¦ ' ' i I ' i —i—i-J—i-1 i i I i i i
0 5 10 15 20 25 30
TALKER TO LISTENER DISTANCE IN FEET
Figure 1$. Simplified chart that shows the quality of speech communica-
tion in relation to the A-weightea sound level of noise (dBA) and the
distance betwi . the talker and the listener.
Figure 4.4 Quality of Speech Communication in Relation to the A-weighted
Sound Level of Background Noise (dB(A)) and Distance between
Talker and Listener (U.S. EPA NT ID 300.7, 1971)
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4-24
from the speech they are exposed to. Since their vocabularies
are just developing, children may have more difficulty understanding
speech amid background noise than do adults. Background noise
probably should not be so great as to hinder the learning
process of our children.
On the other hand, background noise can occasionally be helpful.
An innocuous background noise may be carefully introduced into
some office areas to mask out speech frequencies so that speech
privacy can be assured without soundproofing, when that is otherwise
impractical. It is commonly found in many open-plan officies,
and on occasion, music may be used instead of noise.
(b) Effect of Noise Level on Speech Interference
The effect of background noise on speech interference is
presented in Figure 4.4. The data presented represent the combined
work of several researchers. The lower curve labeled "Expected
Voice Level" separates the region of "Nearly Normal Speech Communi-
cation" from the region of "Communication Possible." The "Expected
Voice Level" line correlates with tests conducted on young, mature
individuals who were asked to write down one syllable words given
to them at consistent "Expected Voice Level" amplitudes at various
distances. This line represented the points at which those tested
were able to write down correctly 90% of the words given to them.
The chart shows that the background noise can be no higher than 66
-------
4-25
dBA for two people to carry on a nearly normal speech conversation
when separated by five feet. This is about as close as two people
are when they are carrying on a personal, non-intimate conversation.
In fact, levels of background noise that require people to move
closer than four feet to each other will usually be unacceptable
to persons who do not normally have an intimate association.
Conversations which take place in a typical classroom or
living room require a maximum background noise level of 50 dBA
for nearly normal communication. This is based on a talker-listener
distance of about 6 meters (20 feet). Some classrooms separate
student and teacher farther than this without the aid of amplification,
requiring the instructor to talk in a raised voice if the background
noise is 50 dBA or greater.
Outdoor activities often require a background noise no greater
than 45 - 55 dBA if nearly normal speech communication is to take
place.
(c) Word of Caution
It is important for the reader to remember the following
in interorptino the above 'lata:
1) It assumes that the speaker has a good knowledge of
the lanauaae and talks clearlv, which may not always
be the case.
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4-?6
The listeners used were young adults who knew the
language well and had mature vocabularies. Children,
who are developing their vocabularies and language
will require less background noise for the same
degree of understanding.
The background noises used contained a fairly
uniform distribution of frequencies. If a parti-
cular background noise is composed largely of fre-
quencies outside the speech range, a listener may
still understand when the noise level is higher
than those on the chart. Unfortunately, this
effect doesn't help very often, because typical
community noises such as vehicles, machinery, lawn-
mowers, televisions, etc. have frequency distri-
butions which cover up our speech frequencies very
nicely.
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4-27
4. SLEEP INTERFERENCE
(a). Introduction
Noise can keep us from achieving the rest necessary
for proper mental and physical recuperation in at least three ways;
it can keep us from going to sleep, it can wake us up, and 1t can
alter our sleep patterns. It take's less noise, in general, to
keep us from going to sleep than 1t does to wake us. Noise
incidents with very low sound levels, such as the well-known
dripping faucet, are capable of keeping us from falling asleep.
But, much more subtle are the effects of noise in waking us, and
in altering our sleep patterns.
A young to middle-aged adult usually requires an average of
7 to 7.5 hours of sleep per day, with children requiring more, and
older people less. However, the less sleep we need, the easier ft
appears for noise to keep us from getting it. If we are not
successful in achieving our dally sleep requirement because noise
has kept us from going to sleep, or it has aroused us several times,
then the results are predictable. We end up with a tired and
unrecuperated body and mind, not quite ready for optimum performance
at whatever the day may hold for us. Fortunately, this condition
is not permanent, and a subsequent night of good sleep is usually
the prescribed cure.
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4-28
After a night's rest, we usually do not recall all the
Incidents 1n which we were awakened briefly. Yet, such arousals
may completely alter our normal sleep pattern. Other noises,
which may not wake us at all, may however, alter our sleep patterns
by shifting us from one stage of sleep to another. Noise incidents
as low as 30 to 50 dBA can do this. The reader is reminded that
30 dBA is quieter than the sound of a male cricket (qrilus sonorous),
chirping just outside our open window. As we miqht expect,
qrilus sonorous would probably not have any of these effects on our
sleep, unless of course, we are exurbanltes who have never heard a
cricket before.
The possible harm which noise may do in altering our sleep
patterns, without actually waking us, is not yet clearly understood,
but it does appear to be a temporary affliction, provided relief
is obtained some time later. Not only does our body require a
certain total amount of sleep each night, but also a certain amount of
time within each sleep "stage".
(Freemon, 1972)
Sleep researchers/categorize our sleep into two states; a REM
state, and a NONREM state, with REM referring to the rapid eye
movements characteristic of that type of sleep. The other sleep
state, (NONREM), 1n which the rapid eye movement does not occur, 1s
further divided into four stages, called simply, 1, 2, 3, and 4. A
typical progression through these various states and stages is
shown in Figure 4.5.
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4-28a
YOUNG ADULTS
L>|-6MTi OUT
HOURS OF SLEEP
Figure 4.5 Typical Sleep Pattern for a Young Adult. Note
that during the latter part of the sleep time
NONREM stages 3 and 4 become increasingly absent and
more time is spent in NONREM stage 2 and in REM.
Also notice the two brief periods when the sleeper
spontaneously awakened. (Miller, EPA, NTID 3000.7, 1971)
-------
4-i^a
Usually about 90 minutes is required from the onset of sleep
to the first occurrence of the REM state. From then on, the cyclic
progressions from one staqe of sleep to another can be more variable,
but the overall quantity of sleep must be adequate 1n each stage to
accomplish the several functions which sleep 1s thought to serve in
our general health and well being, some of the more obvious phenomena
are shown in Figure 4.6. So 1t would appear that the quality of our to-
tal sleep experience should also be evaluated on the basis of our
ability to achieve our sleep requirements 1n each of the various
states and stages of sleep.
-------
NONRt'M STAGES
PHENOMENON
KEM
1
2
3
4
1. Portion of total sleep time
20%
10%
50%
20%^
2. Dreaming occurs in
(1)
/
/
~
/
(2)
/
3. Body movement inhibited in
/(3)
4. Sleep walking occurs in
~
/
5. Growth hormone produced
primarily in
**
/
/
6. Other hormones are produced
In
(4)
/
7. Learning and cognitive
thought process can occur
while asleep in
/5)
/
8. Snoring usually in
/6)
/(7>
(1) 80% of dreaming, usually in color, unrealistic, abstract,
believed to relievepsyeholoqlcal stress
(2) severe niqht terrors occur
(3) controlled by state of brain not by production of hormone
(4) Cortisol, testosterone, anti-diuretic hormone, luteinizing
hormone
(5) problems studied in daytime can be solved here
(6) majority effort here
(7) some effort
(8) some effort
:igure 4.6 Phenomena Primarily Associated with Various Stages of Sleep
(Freemon, 1972)
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4-30
(b) Effects of Noise on Sleep
In discussing the actual effects of noise on sleep, 1t 1s
well to keep 1n mind how complex our sleep processes are. Because
of this, we can expect noise to have different effects when we are
1n different stages of sleep, and with wide variation 1n the effects
on different individuals. However, there 1s sufficient research
available to serve as an initial guideline for evaluating the sleep
effects of noise on you and your community.
First, Figure 4.7 shows us the sound levels of brief noise
Incidents which are sufficient to cause an interruption of our
normal sleep pattern without actually waking us. These data were
obtained by exposing sleep deprived college students to brief
noises of various types. Presumably somewhat less noise would be
required to shift sleep stages if the sleepers were not excessively
tired or the noises were longer or more meaningful.
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4-30a
INITIAL STAGE OF SLEEP
NOISE LEVELS SUFFICIENT TO
CAUSE INTERRUPTION OF NORMAL
SLEEP PATTERN
REM
30 90 dB(A)
1
(believed to be similar to
NONREM stage 2)
2
30 -v- 40 dB(A)
3
50 dB(A)
4
80 dB(A)
Figure 4.7 Noise Levels Sufficient to Cause Shifting from One Stage
of Sleep to Another without Causing Awakening
-------
4-31
A second series of data, (Figure 4.8) shows the various levels
of noise which may interrupt our sleep pattern by waking us completely.
The dashed curve to the left shows the probability of noise waking
us from NONREM stage 2. The dashed curve to the far right shows
the probability of noise waking us from the deep NONREM stages 3 and 4.
In terms of simplification, the solid curve 1n the middle represents
a middle of the road average. It shows the probability of noise waking
us without regard to what stage of sleep we are in. As would be expected,
the solid curve is closer to stage 2, since we spend more time
sleeping in stage 2 than in stages 3 and 4.
The remainder of this section deals with some miscellaneous
observations relating to the effects of noise on sleep. It is
by no means an exhaustive list, but serves to illustrate the kinds
of things that must be considered in regulating noise to minimize
its effects on health and welfare.
1) Hearing Loss Helps
If we have already suffered some hearing loss, it will
take more noise to disturb our sleep than 1f we have normal hearing.
The data shown in Figures 4.7 and 4.8 above are based on the
assumption that the sleeper's hearinq 1s normal. If we have
already suffered some hearing loss and our average threshold of
hearing is now 20 dB, then we might expect that the noise required
to interrupt our sleep would now be 20 dBA higher than those shown.
By the same token, the figures indicate that young children may
have their sleep disturbed by noise levels less than those above,
since their threshold of hearing is often much better than 0 dB, some-
-------
4-31b
dBA" INDOORS -BRIEF SOUNDS (UNDER 3 MINUTES)
Figure 4.8 Probability of Noise Levels to Cause Complete Awakening
(Miller, EPA, NTID 300.7, 1971)
-------
4-82
times as low as -20 dB, (Eagles, et.al, 1963). However, as Indicated
in (6) below, the sleep of children often seems to he hlecsed from
noise Interruption.
2) Background (L^q) Noise May Help Mask Out Interrupting Noises
Again, a noise can Interrupt our sleep only 1f we perceive
1t. If the background noise level 1s high enough to make 1t
Impossible for us to hear particular noises, then they will not
disturb our sleep. Two comments, before we all rush to start
piping 70 dBA noise Into our homes at night. First, most
of us are exposed to enough noise during the day to require as
much nighttime quiet as possible in order to protect our hearing.
The need for this "down time" from noise decreases the desirability
of "upping the ambient" during our sleep. Secondly, there is
some evidence that even continuous noise, as contrasted with
Isolated incidents of noise, can affect our sleep 1f the levels
are high enough.
3) Brief Noises are Less Sleep Disruptive than Longer Ones
The frequency of awakening 1s lower for single noise
impulses than 1t is for noises of longer duration, such as the pass-
ing of a motorcycle, truck, or other vehicle and aircraft. For
these longer noises, the frequency of awakening increases as the
noise level increases. Thiessen found that for brief noises the
probability of subjects being awakened by a peak sound pressure level
of 40 dB(A) was 5%, 1ncreas1nq to 30% at 70 dB(A). He found that the
probability increases to 10% for 40 dB(A) and 60% for 70 dB(A)
if one also considers the interruptions of our sleep pattern
which do not cause awakenings.
-------
5) Some Noises are Ignored
Our brains are capable of deciding whether or not
the Information content of a noise which we hear warrants dis-
turbing our sleep over it or not. A mother may awake to the
soft whimpering of her child or to an almost silent creaking
of a doorknob being opened 1n themlddle of the night, and
yet not be disturbed by the much louder noise of the furnace
or the hot water heater turning on. To some extent we can
also be motivated to ignore or respond to particular noises.
This ability to discriminate, which works/best if learned
when we are awake, is more pronounced in the REM and NONREM
1 and 2 stages of sleep.
6) Some Adaptation Can Occur
To a limited extent our sleep becomes less frequently
Interrupted as we grow accustomed to routine, unalarming noise
incidents. We are most likely to adapt by either not waking up
at all or for not as long as before. However, the evidence indicates
that we may never completely adapt, as demonstrated by studies con-
ducted on sleepers exposed to aircraft noise. In general, the loud-
er the noise the less likely it is that total adaptation will take
place. Shifts in our sleep pattern without actually awakening are
more likely to continue without adaptation.
7) Being Very Tired Helps
The more physically tired we are the easier it is to
go to sleep and to stay asleep. Of course, making sure that you
are sleep deprived is not a good full-time solution to gettinq a
good night's rest. Noise incidents interrupt us less at the
-------
4-34
beginning of a niqht's sleep than near the end of it when we are
less tired. This gives us more assurance of obtaining uninterrupted
"deep" sleep in NONREM staqes 3 and 4 which occur predominantly
toward the early portion of our sleep period; but makes it more
difficult to obtain the important REM state of sleep which is
predominant near the end of our rest period and is considered by
most sleep researchers to be the state of sleep most sensitive to
noise interruption.
8) Children are Affected Less
Perhaps because of their strong need for physiological
rest, children are not as sensitive to most noise interruptions as
are adults. However, children from 4-6 years of age seem to be
particularly dlstrubed by sudden arousal from NONREM stage 4.
General sleep distrubances such as night terrors occur in
stage 4 sleep and are common among children 1n this aqe group.
Senior citizens are much more sensitive to noise interruptions
than are children or other adults. This effect is very large
and dramatic, as evidenced by sleep research data and the number
of sleep interruption complaints received 1n communities from
older people. Lukan R Kryter ( ) found that simulated sonic booms
that will awaken middle-aged adults and 7 and 8 year old children
on less than 5$ of their occurrences will awaken 69-72 year old
adults on nearly 703! of their occurrences. Again the general rule
that "the less sleep an individual requires the more difficult it
is to obtain 1t" appears to hold.
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4-35
9) Mon are Less Susceptible to Noise Interruptions
Tfian "are Women
All other things being equal, adult women's sleep 1s
more sensitive to noise Interruptions of all types than is that
of men. -Women awaken more easily and have their sleep shifted to
different stages more frequently.
10) Healthy are Less Disturbed than S1ck
So, stay healthy. The caution 1s obviously aimed
toward protecting the sick. Physically 111, and usually,
mentally ill people are more easily interrupted from sleep by
noise. So, when we're sick, we require a sleep environment
as free from noise incidents as possible particularly in the
vicinity of hospitals, to aid our recovery.
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4-36
OTHER PHYSIOLOGICAL EFFECTS
(a) Discussion
From time to time fears are expressed that noise might kill
us, cause heart attacks, or cause a newborn child to be deformed.
There is no reliable justification for any such claims. Noise
can, however, make us deaf, interfere with speech communication,
ruin our sleep, and cause us to act in most antisocial ways. In
addition to the effects already discussed, noise does cause a
broad assortment of physical and physiological effects which are
briefly mentioned below, but none of these effects should pro-
bably cause us great alarm in considering our typical noise
environment. They are more often involved when the noise environ-
ment is unusual in some important regard. More research is needed
to clarify the actual role noise plays in producing these effects.
Perhaps the best step which a community can take in addressing
these problems is to incorporate into its noise program, the
educational task of alleviating undue fears and concerns among
citizens by using what information j_s available, while watching
carefully for the results of continuing research.
In addition to the effects which already been discussed, we
may experience pain in our ears and head when noise levels reach
140 dBA, which is about as loud as a small jet aircraft taking off
50 feet over your head. This pain threshold is a result of the
stretching of our eardrums and usually will present us with a pro-
blem only if we have suffered significant hearing loss or other
-------
4-37
hearing disorders which cause the pain threshold to lower from
140 dB(A). At about 120-130 dB(A) we may experience some dis-
comfort or tickling sensation in our ear canal.
Exposure to sound pressure levels in excess of 130 dB(A)
may cause us to become dizzy, experience involuntary eye movements
and symptoms of vertigo. We can begin to lose our sense of
balance at noise levels above 120 dB(A). Such high noise levels
need not be a part of our noise environment.
Vasoconstriction is a physiological effect of noise which
bears some watching in the research to come. Noise levels above
70 dB(A) cause the small blood vessels near the surface of our skin,
especially those in the fingers, toes, and ear lobes to constrict,
causing as much as a 40% change. These changes result in a small
increase in blood pressure and heart rate. The amount of con-
striction is a direct function of the noise level above 70 dB(A).
As the noise level goes up, the blood vessel contracts }as the
noise level goes down the blood vessel size returns toward normal.
Apparently we show very little adaptation to the continuation and
repetition of the noise with vasoconstriction often continuing
1965).
for a considerable time after the noise stops (Jansen,/0ne possible,
although as yet unsupported, problem could result from the vaso-
constriction of the capillaries which carry blood to the vicinity
of the hair cells, which are within the sound field propagating
in the fluid of our inner ear. As the noise amplitude increase,
the recuperative flow of blood to the hair cells is being reduced
perhaps hindering the hair cells from recovering from fatigue and
-------
4-38
thereby contributing to temporary and permanent hearing loss.
Furthermore, the louder the noise the greater is the hair cell's
demand for fresh oxygen giving blood; but noise is reducing that
supply of blood.
Associated with our arousal response to unexpected noise
1s the paling of some mucous membranes and increased hormone
production as well as physical changes in several glands, such
as, the pituitary, adrenalin, and hypothalamous glands. (Welch and Welch,
1970).
We show very little adaptation to these effects which continue
with repetition of the noise but which are only temporary and dis-
appear when the noise goes away.
Nature has equipped us with orienting and startle reflexes
which begin to operate at low levels of noise. When we hear a
sharp, alarming, or curious noise we instinctively respond,
usually by turning our head and body with its senses toward the
source of the sound. The startle reaction occurs primarily to
protect us from a possible danger signalled by the sound. This
response to noise has associated with it all of the typical
responses from arousal reactions, including psychological stress,
eye blinks, facial grimaces, increases muscular tension, pulse,
respiration rate, endocrine activity, and reduction of digestive
activity. The effects are also temporary and disappear within a
few minutes after the startling noise ceases. Some adaptation
can occur if the noise is not too abrupt or too loud or definitely
associated with danger. However, even experienced marksmen continue
-------
4-39
to exhibit bumc startle response each time they fire a gun. Sounds
which we cannot hear, infrasound with frequencies less than 16 Hz,
or ultrasound with frequencies greater than 20,000 Hz, can still
have some significant effects on us if the noise levels are very
high - say from 100 dB to 160 dB.
Infrasounds have been reported to cause effects resembling
mild stress responses, general feelings of discomfort, disorientation,
chest wall vibration, gagging, respiratory rhythm changes, head-
aches, coughing, visual blurring, fatigue, giddiness at high
noise levels. Sources of such sounds may include air heating and
air conditioning systems, jet aircraft, and other transportation
systems, including high power propulsion systems utilized in space
flights. Intrasounds occur in nature usually at relatively low
intensities. Very low frequency sound can come from earthquakes,
volcanic eruptions, winds air turbulence, thunder, large waterfalls,
and the impact of waves on beaches. It appears that exposure
to infrasound at intensities below 130 dB(A) does not present a
serious health hazard. However, most of the danger with hi ultrasonic
frequencies result from the fact that sonic (audible) frequencies are
also present.
Ultrasonic frequencies above 20,000 Hz are produced by a wide
variety of sources such as high speed drills, cleaning devices, gas
turbines, jet engines, and electronic systems. Fortunately for us
such high frequencies are absorbed very quickly by air; therefore,
any problems we might have with ultrasonic waves occur very close
-------
to the source of the sound. Some workers working near jet engines
producing ultra sound above 105 dB have had difficulties with
headaches, nausea, excessive fatigue, vomiting, and focusing their
eyes.
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4-41
6. ANNOYANCE
(a) Discussion
Irate citizens, annoyed by noise, are the most frequent
impetus for a community to begin the process of enacting its
own noise ordinance and establishing a noise control program.
These citizens are often less concerned about the potentially
harmful effects of noise, such as hearing loss, speech inter-
ference, and sleep interference, rather being motivated into
action by the sheer annoyance of noise.
Sound conclusions concerning the physiological effects of
annoyance are hard to find. However, if one considers the
broader definition of health proposed by the World Health Organ-
ization (WHO) as the Environmental Protection Agency does, which
refers to the total social and mental well being of an individual,
and not merely to the absence of disease, then the psychological
and social aspects of annoyance may also be seen as "health effects".
Schemes for quantitatively predicting annoyance are avail-
able and show good correlation (better than 90%) for predicting
the annoyance response of an entire community, but a somewhat
poorer correlation with individual annoyance response to noise.
It is important for us to remember that only 2-20% of those who
are highly annoyed by noise ever register complaints.
Also, annoyance is significantly reduced even though the noise
may remain unchanged if a conmunity noise control agent is
responding to the problem or if the noise makers are conscientiously
attempting to reduce the noise impact. Thus, there may be definite
value in
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4-42
establishing a community noise control program with an Environ-
mental Protection Officer who is:
1. Clearly identified as the individual to whom
noise complaints and problems are to be directed.
2. Responsive to those complaints, using his enforce-
ment role of the noise ordinance, if necessary, as a
lever to encourage the cooperation the noise maker
in solving the problem.
Qualitative observations concerning both the physical and
psychosocial aspects of noise which are related to annoyance
include the following.
The
physical factors which increase annoyance include:
1,
A higher noise level
2.
A higher frequency
3.
A longer duration
4.
Discrete frequency components
5.
Impulses
6.
Abrupt onset or cessation
7.
Harsh or rough qualities
8.
Intermittent loudness, pitch, or rhythm
9.
A larger difference between the noise level of the
noise incident and the background noise
10.
An unpredictable character.
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4-43
Studies of psycholoqical and sociological factors which
increase tlie receiver's annoyance include:
1. fnar associated with activities of noise source such
fs fear of crashes in the case of aircraft noise
2. Inappropriateness of the time of day 1n which the
noise occurs; i.e., sleep time
3. The extent to which the receiver lacks control over
the noise
4. T'te extent to which the receiver believes the noise
could be controlled and if not
5. Negative attitude of the receiver regarding the ultimate
contribution of the activities associated with the noise
source
6. The extent to which the receivers believe they are not being
treated fairly
7. TKe educational level of the receiver
8. The socio-economic status of the receiver
9. T ie unobliging attitude of people toward the noise makers
10. 11e decree of frustration from previous experience
11. Tle pervasiveness of the noise - is it possible to get away
from it.?
Sever.'1 ratinn schemes are available which attempt to predict
the decree of annoyance suffered from noise by individuals and com-
munities a whole, based on sound measurements made in the field
and social surveys conducted to evaluate many of the factors
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4-44
considered important above. One of the more useful of these
predictive schemes is depected in Figure 4.9 which shows the
percentage of people who are hlqhly annoyed by noise. This
annoyance is shown as a function of Lfjn (Day-N1ght Average
Noise Level) which 1s defined and discussed on page 3-28.
Notice the low percentage of "complaints actually received by
the community. An l_dn as low as 50 corresponds to 13% of the
community beglng highly annoyed, while less than 1% of than have
actually complained. An of 70 corresponds to 44% of the
community being hlqhly annoyed, while only 10% of them com-
plained. This again points out the need for a community to be
highly responsive to those who do complain, particularly since
sociological surveys Indicate there 1s a high correlation between
those who complain and those who are actually annoyed in the
community and may not complain.
-------
PERCENTAGE
COMPLAINANTS
20
15
10
COMMUNITY
REACTION
-t— Vigorous Action
Complaints of Threats
of Legal Action
•^"None
50 60 70 80 90
Day-Night Average Noise Level, L^n In dB
Figure 4.9 Individual Annoyance and Community Reaction as a Function of L
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4-45
7. OTHER PSYCHOLOGICAL EFFECTS
(a) Discussion
Psychological stress is usually the compound result of many
factors. Noise is only one such source of stress and it is
difficult to isolate the role that noise alone plays in causing
us psychological stress and frustration.
Each of the noise effects cited thus far in this chapter can
serve as an indirect source of stress. For instance: it can be
depressing and frustrating for us and those around us if we cannot
hear because we have lost part of our hearing as a result of noise;
1t can be extremely frustrating for us to have our conversation
repeatedly interrupted by excessive background noise; or to observe
the social and psychological problems resulting from the retardation
of a child's learning processes because of noise interference; even
a goodnight's rest is important to our feeling of well-being --
we are not as confident in our ability to face the day's tasks
if noise has hindered our sleep, but our varied responses to particular
noises are probably our most obvious source of noise-induced
psychological stress. These stresses are temporary and presumably
would disappear if the noise disappears.
There is some inconclusive evidence that noise can contribute
to more long-term neurotic or psychotic illness; however, additional
research is necessary to document the extent of the noise role. In
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4-46
a study near London's Heathrow Airport, Abey and Wickrama report the
rate of admissions to mental hospitals is higher from areas experiencing
high levels of noise from aircraft operations than in similar areas
with lower levels of noise. The type of person most affected appears
to be the oltler woman not living with her husband and who suffers
from neurotic or organic illness. These authors do not believe
aircraft noise causes mental illness, but their tentative conclusion
is that such noise could be a factor that increases admissions to
psychiatric hospitals. Additional research is currently underway
near the same airport with improvements intended to better isolate
the effects of noise. It would be wise for your community Environmental
Protection Officer to follow closely the work of this future research
and incorporate these findings in the educational portion of the
noise control program, pointing out the possibilities of potential
increases in performance as a result of stress relief corresponding
to noise reduction.
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4-47
8. FDUCATIONAL RFTARDATION
(a) Introduction
The fact that noise can cause hearlnq loss 1s well known
and documented. Noise has other effects on hearing, however,
which do not Involve actual damage to the ear, but rather
Interfere with normal hearing. This interference (as discussed
earlier in Section 3 of this chapter) may have profound effects
In situations where speech communication is essential, one of
which 1s the education of children.
In the case of steady-state noise levels, it can be pre-
dicted fairly well how speech communication will be affected,
facilitated, or perhaps even prevented (as In the case of speech
privacy). Indeed, most studies of speech interference are
reported in terms of the percentage of words heard correctly
under specific noise conditions.
For intermittent noises, however, such as aircraft flyovers,
the effects are quite different and most references merely note
that at certain levels, conversation may need to be held in abey-
ance until the noise source has diminished. At most, they might
quantify the number of times or the amount of time such inter-
ruptions occur. Virtually no mention is made of what might be
called the "after-effects" of these noise interruptions, nor are
they reflected in the various calculations of speech interference.
These after-effects might include disruptions in a train of
thought, the necessity of redoing a lengthy calculation, or
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4-48
the loss of a listener's attention, among many others with
which each of us is probably all too familiar. While these
effects may be a source of annoyance to many adults, they may
have more serious consequences for the learning process in
children, and may spell educational disaster for some of those
afflicted with specific learninq disabilities, or minimal hearing
loss, for example.
(b) Noise in the Classroom
In examining the literature on the effects of noise in the
classroom, it is important to distinguish between those studies
dealing with typical background noise levels resulting from
internal sources, such as the classroom activities themselves,
and those from external sources such as aircraft flyovers, traffic
and olayground noise, and ventilating systems.
For example, Vernetti and Jacobs (1972), Park and Payne (1963),
Slater (1968), and Sander (1965), have all reported that no signifi-
cant effects were noted on specific performance tasks with varying
levels of noise in the background. However, the critical variable
here is the level of the noise. In two of the cases, levels were
not given in decibels, but the description clearly indicates that
these were those of typical classroom activities; and the other
two indicated levels of 65-70 dE(A) which, again, are within the
category of normal background activities.
These examples are typical of many of the available studies
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4-49
which purport to deal with the effects of noise 1n the classroom,
and since some of these tend to have similar results, I.e., no
Important effects on performance, there 1s a tendency to assume
that no Interference with the education process exists, and indeed,
a biased sampling of the literature could support that conclusion.
It should be noted that none of the above levels are con-
sidered desirable from the standpoint of either good classroom
design, or user acceptance, but at least they were not associated
with decreased performance by pupils (for those specific tasks and
conditions).
There are, however, other studies with conflicting findings:
Brown (1966), Broadbent (1953), and Holloway (1972) have all noted
significant effects on certain tasks from the presence of moderate
extraneous noise. Glass and Singer (1973) show impressive examples
of degraded performance on auditory discrimination tests with
children who had had long-term exposure (more than 4 years) to
moderate noise, and suggested that this may have important Impli-
cations for reading proficiency.
More important, however, none of the situations reported are
in any similar to the much greater magnitude of disturbance
associated with aircraft flyovers, traffic, and other similarly
Intermittent noise Intrusions.
Meecham and Lane ( ) have reported that as much as 120
minutes of time may be lost (speech communication impossible)
during each school day due to Jet takeoffs and landings in schools
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4-50
near a metropolitan airport. Noise levels in these schools range
between 95 and 105 dBA during each flyover. When one considers
that these flyovers last for 10-20 seconds and occur one or two
minutes, it is evident that there 1s an impressive reduction in
the teaching day, but teachers report that the actual time lost
for instruction is considerably greater, due to factors such as
(1) time reguired to regain attention and restore a train of
though; (2) reduced motivation for both teacher and student;
(3) fatigue and irritability. A quote from one of the teachers
illustrates the problem well:
"Tonight, my nerves are shot. I struggled all day in
a losing battle against those jets. The children couldn't
hear me, and I couldn't hear them unless I stood 18 Inches
away"
Again, good research on this problem is not easy to find, but
if there is any validity to our concept of education, it must be
based on the assumption that some useful purpose is being served
by the ti>p spent in the classroom, so losing 2-3 hours of it to
noise must necessarily have its effect on that education.
(c) Mining Hearing Loss
If oni' considers the cumulative effects of a noise-impacted
classroom and a child who has an unremedlated hearing loss, the
potential ror educational retardation becomes even more significant.
Kundert C1 72) has shown that as many as one child 1n ten may have
a minimal nearinq loss which escapes detection in school hearing
screening rograms, and yet leaves him at an auditory disadvantage
-------
4-51
compared to his peers. This disadvantage is extended when one
considers that most younq chlldrens' hearing acuity 1s actually
much better than the so-called " norms" (Eagles 1961). Thus he
may be suffering form the equivalent of a 30-dec1bel hearing loss
relative to other students In the class and still be considered
"within normal limits" for hearing acuity. It 1s no surprise then,
that when a teacher is looking for possible causes for a child's
underachievement or behavior, she would not consider hearing loss.
Preliminary results in Kundert's data suggest that these
children with minimal hearing losses (good enough to pass screening
tests, but poorer than Eaqles (1961) norms for young children) may
indeed be performing worse than children with more normal hearing
on standard achievement tests. Further work with a large? sample
under more rlqldly controlled conditions 1s needed, however.
In any case, whatever handicapping conditions may result from
minimal hearing loss, it is safe to assume that they would be
aggravated by the intrusion of excessive noise into the classroom,
where the usual effects of speech Interference would be perceived
more acutely by the Impaired hearing.
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4-52
9. PERFORMANCE LOSS
(a) Discussion
Our performance can be affected if problems develop in any
of the areas discussed previously in this chapter, such as hearing
loss, speech interference, sleep interference, annoyance, and others.
Anything which affects our health and well being, either permanently
or temporarily will probably affect our performance to some degree.
When we are working optimally at a particular task, any noise
distraction may represent a loss of concentration and thus, performance.
But for some tasks, particularly if they are boring or routine, the
addition of noise can improve our work output. But in most situations,
our optimum oerformance is possible only with minimum noise'in our
environment. However, we are not always in good health, fully rested,
or well-motivated for the task at hand. In those cases, low-level
noise may increase our state of arousal and improve our performance.
Broadbent, (1973), Kryter (1970), Woodhead (1964), McGrath (1963),
and others have conducted studies seeking the significance of noise
relative to job performance. In general, they have found that steady
noise seem to interfere with human performance when the noise level
exceeds 90 dBA. However, intermittent and imDulsive noises are more
disruptive, even below 90 dBA, especially if the noise contains
high frequency components. It appears that noise is nore likely
to reduce quality of work rather than quantity.
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4-53
Complex or mentally demanding tasks are more adversely Influenced
by noise than simple tasks. Cohen ( 197has reported a five-year
field study of medical > attendance and accident files for approximately
1,000 workers in factory situations. Five hundred of these workers
were employed in noise levels of 95 dB(A) or above, and the other 500
in 80 dB(A) or below. The workers located in the higher noise level
showed significantly greater numbers of job-related accidents, sickness,
and absenteeism than their counterparts in the quieter jobs. Since
the types of jobs in the noisy and quieter areas could not be equated,
the possibility exists that the tasks in the noisy areas were inherently
more hazardous for reasons other than noise. A community's Noise Control
Officer should watch for future research in this area.
Glass and Singer ( 1973) have suggested that our vision can become
more selectively receptive after noise exposure, that is, focusing
on objects in the center of our field of vision while ignoring
more peripheral objects. Particular noise incidents cannot only
interrupt our work, but we may experience recovery time slack
performance after the noise interruption. Woodhead found that a
one-second noise burst can have a residual effect on our performance
of from 15-30 seconds. Similar after effects have been reported from
sonic booms and aircraft flyovers.
Our performance, that of our company, community, and country is
important to the development of mankind. We should be cognizant of
and evaluate for ourselves the effects that noise has on our performance.
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4-54
It would be v/ise for your community's Environmental Protection Officer
to follow closely the work of future research and incorporate these
findings in the educational portion of the community's noise control
program, pointing out the possibilities of potential increase in
perfornance as a result of noise control.
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CHAPTER 5
TECHNICAL AND ECONOMIC FEASIBILITY
5-1
-------
CHAPTER 6
THE LEGAL BASES FOR COMMUNITY NOISE CONTROL
I. FEDERAL GOVERNMENT
The legal basis for noise control at the Federal level
devolves from the Constitution of the United States. As
determined by the Constitution, the Federal government is
vested with only those powers specifically enumerated therein;
any other powers, not specifically forbidden to them, remain
in the States. Article III of the Constitution give Congress
the specific power to regulate interstate and foreign commerce.
Under this authority, Congress passed the Noise Control Act of
1972 (42 U.S.C. §§4901 et seq.), which regulates noise emission
levels of products and vehicles which are in interstate and
foreign commerce. Specifically, this Act requires that the
U.S. Environmental Protection Agency (EPA) set maximum noise
emission levels for new products which are major sources of
noise and which are shipped or sold in interstate commerce or
imported for sale. The EPA is also required to promulgate noise
emission standards for the operation of motor carriers and sur-
face rail carriers engaged in interstate commerce.
Certain areas of State and local authority will become
preempted on the effective date of EPA regulations promulgated
pursuant to Sections 6, 17 and 18 of the Noise Control Act.
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-2-
Preemption under Section 6 is relatively narrow, providing
that after the effective date of an EPA regulation prescribing
noise emission levels for a specific new product, or component
of a new product, no State or political subdivision thereof
may adopt or enforce with respect to that particular new product
or component any law or regulation which sets a noise emission
limit on such product or component enforceable against the
manufacturer of the product, applicable at the time of sale,
unless such law or regulation is identical to the Federal
regulation. Thus, the preemption is against any State or local
law which regulates the noise levels of a new product (i.e., a
product which has not yet been sold to the ultimate purchaser)
and which, at any time, impacts the manufacturer of the product.
Under Subsection 6(e)(2), State and local governments
retain authority to control products by all other available
means. This subsection states that nothing in this section
precludes or denies the right of State and local governments
to establish and enforce controls on environmental noise and
sources thereof through the licensing, regulation or restriction
of the use, operation or movement of any product or combination
of products.
Thus, although a local government, may not enforce a non-
identical local law limiting the noise level of an EPA-regulated
new product which affects the manufacture or sale of such product,
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-3-
the local government may regulate the product noise impact
through regulations enforceable against the owner or operator
of the product. Regulations may provide, for example, curfews
on operation, prohibition of use in a residential neighborhood
or hospital zone, or requirements for periodic inspection and
certification of the product.
Broader preemptive coverage is found in Sections 17(c)(1)
and 18(c)(1) of the Noise Control Act. These sections provide
that, after the effective date of an EPA regulation applicable
to noise emissions from interstate rail or motor carriers, no
State or political subdivision thereof may adopt or enforce any
standard applicable to the same noise source unless such stand-
ard is identical to the Federal standard. However, Sections
17(c)(2) and 18(c)(2) provide that nothing in these sections
shall diminish or enhance the right of State and local govern-
ments to establish and enforce standards or controls on levels
of environmental noise or to control, license, regulate or
restrict the use, operation, or movement of any regulated pro-
duct if two conditions occur: (1) the EPA Administrator, after
consultation with the Secretary of the Department of Transporta-
tion, determines that such local law is necessitated by special
local conditions; and (2) the EPA Administrator determines that
such local law is not in conflict with the EPA regulations.
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-4-
Thus , on the effective date of EPA regulations under
Section 18 (October 15, 1975) and Section 17 (undetermined as
yet), local regulations providing standards on noise emissions
resulting from operations subject to Federal regulations must
be identical to the Federal regulation. Such identity applies
not only to the standard but also to any regulatory element
which affects the identity of the standard, such as measure-
ment methodology. Non-identical standards may not be enforced
and should be declared ineffective.
In general, the preemptive effect of Sections 17 and 18
on local law can be classified into three categories. First,
any local law which sets noise emission levels for interstate
motor vehicles and railroad locomotives and cars must be
identical to the Federal standard. No special local condition
or other factor can exempt this requirement. Second, local
laws which regulate or restrict the use, operation, or movement
of interstate motor or rail carriers by such means as curfews
or truck routes will not be subject to preemption if (1) the
principal purpose of such regulation is not to control noise,
or (2) the principal purpose is to control noise but the regula-
tion has been approved by EPA as necessitated by special local
conditions and not in conflict with the Federal regulations.
For example, truck routes designated solely on the basis of
noise control must be submitted to EPA for determination of a
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-5-
special local condition. Truck routes based on additional
factors, such as the safety of children, maximum load on street
surfaces, etc., will not need EPA approval. Third, general
noise regulations, such as property line noise emission stand-
ards (Article VIII), will not be affected by these preemption
provisions except in rare cases. Thus, the property line levels
may be applied to noise emissions caused by interstate motor
carrier vehicles at a loading terminal so long as means of
abatement are possible which do not require controlling the
noise emission level of the motor vehicle itself. Such other
means of abatement can include, for example, installation of
noise barriers at the perimeter of the terminal and creation
of buffer zones of land between the terminal and the noise-
impacted areas.
II. STATES AND THEIR POLITICAL SUBDIVISIONS
The U.S. Constitution does not grant the Federal govern-
ment the power to regulate matters relating to the police power,
nor does it prohibit such regulation by the States. Therefore,
under the Tenth Amendment, the States are the repository of the
police power, which includes authority to regulate matters
relating to public safety, public health, morality, peace and
quiet, law and order. In turn, the States, either under St&te
constitutional provisions for home rule or under specific State
enabling statutes, grant to municipal corporations and certain
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-6-
other political subdivisions (depending upon the constitution
and/or statute) authority to regulate matters pertaining to
the police power, for example, authority to protect the public
health and welfare. It is this authority to protect public
health and welfare, as well as authority to abate nuisances
and control land use, which provides the legal basis for noise
control at the State and local level.
The Noise Control Act of 1972 recognizes the importance
of State and local governments in noise abatement. In Section
2(a)(3) the Congress found that "primary responsibility for
control of noise rests with State and local governments." Congress
further declared that "it is the policy of the United States
to promote an environment for all Americans free from noise
that jeopardizes their health or welfare." To assist local
governments in contributing to this goal of noise abatement,
Section 14(2) of the Noise Control Act authorizes EPA to
Provide technical assistance to
State and local governments to
facilitate their development and
enforcement of ambient noise
standards, including but not
limited to-
(A) advice on training of noise-
control personnel and on selec-
tion and operation of noise-
abatement equipment; and
(B) preparation of model State
or local legislation for noise
contol.
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-7-
components of a
The purpose of this workbook is to present possible / community
noise control ordinance and related assistance to communities
interested in developing a local noise control program.
Local regulation of environmental noise comes within the
scope of the police power. Modern noise abatement regulations
are based primarily on the use of the police power to protect
the public health and welfare. Certain types of regulations
are also based on the power to abate nuisances and to control
land use. In the past, the authority to abate nuisances has
been the typical basis of noise control. Ordinances prohibited
"excessive" or "unusually loud" noise. These ordinances were
poorly enforced and prosecuted due to the subjective basis.
Recent ordinances, drawing upon the growing body of knowledge
on the health and welfare effects of noise, have objective
standards regarding the levels of noise which may be permitted
without damage to public health and welfare. State and local
regulations which are based directly on the known health and
welfare effects of noise and which specify maximum noise levels
for various products, operations, or uses of land have the
advantages of greater ease in enforcement, with regard to the
determination of the existence of a violation, and greater ease
of prosecution in court. However, to provide an adequate basis
for such regulations, the community should determine the levels
of noise it desires to achieve to adequately protect the health
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-8-
and welfare of the community and indicate the background data
on these levels. The Federal Environmental Protection Agency,
despite the fact that its regulations under the noise control
act are not based on the police power, has collected all
known information regarding the effects of noise on human
health and welfare (published in the document Public Health
and Welfare Criteria for Noise! V.) The EPA has also determined,
as goals for noise abatement, the levels of environmental
noise which must be attained to protect health and welfare
(contained in Information on Levels of Environmental Noise
Requisite to Protection Public Health and Welfare with an
Adequate Margin of Safety.—/) These documents, their references,
and material contained in Chapter 4 of this workbook can be
utilized by a State or local government as the scientific
basis for the choice of noise levels to protect public health
and welfare in the local noise control ordinance.
The EPA documents represent goals in noise abatement and
do not take into account technological feasibility or economic
impact. Each community should choose its levels and times of
curfews on the complete set of environmental, health, economic
and other goals that it wishes to attain. Chapters 2 and 4
describe a procedure whereby goals may be selected and standards
promulgated which consider economic and social, as well as health
and environmental, impacts.
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-9-
In addition, State and local governments have, under the
scope of the police power, the authority to define and abate
nuisances. Most older noise ordinances were based on this
authority, and prohibited "excessive" or "unnecessary" noise.
Enforcement and prosecution of this type of ordinance have
generally followed the law of nuisance as it has been developed.
The definition of whether a particular noise is "excessive" or
"unnecessary" has been left to the courts. The courts often
balance the interests of the person being impacted by the noise
with the interests of the person producing the noise. Thus,
although a source of noise may be considered "excessive," it
may also be found to be "necessary" and preclude enforcement
against the source. This type of ordinance, therefore, can
create difficult problems in the determination of whether a
violation exists and in the prosecution of the alleged offender.
Such an ordinance is not generally as protective of the public
health and welfare as is a performance standard type of ordinance.
However, nuisance provisions are important in a comprehensive
noise ordinance as a back-up to performance standards to treat
certain types of problems, such as barking dogs and noisy
parties.
Another local power utilized in the model ordinance is that
to control land use. Land use control has been exerted tradi-
tionally at the local level and, in the context of the
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-10-
workbook, it is utilized to protect the health and welfare
of persons in sensitive receiving land uses, particularly
residential and institutional. Such protection is from both
existing sources to existing receiver (Article VIII) and from
existing and potential sources to potential receivers (Article
X). This latter type of protection, afforded by good land use
planning, is particularly important in noise control because a
large proportion of potential noise problems can be avoided by
such planning.
Thus, it is recommended that, in all areas where it is
practicable, a community adopt performance standard provisions
in its noise ordinance. Nuisance-type provisions can be used,
however, whenever needed as a back-up to the performance
standard provisions. The full range of these regulations will
be presented in Chapters 2 and 7 and specific recommendations
for usage will be made at that time.
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CHAPTER 7 COMPONENTS OF A COMMUNITY NOISE ORDINANCE
This chapter provides an extensive listing of noise
ordinance provisions and relevant definitions. With each
provision there is a full discussion, explaining the meaning
and intent of the words. In cases where specific noise limits
can be used in the ordinance, there are tables or graphs of
data, indicating what other communities have done, or showing
the existing sound levels of some device to be regulated, so
that appropriate numbers may be chosen.
Intended readership: Those individuals charged with
actually assembling an ordinance.
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EXPLANATION OF FORMAT
Each Article, Section, or Subsection for a noise ordinance is set
out in the text below by italics, except for the titles. Some sections
will have several choices or alternatives which will be marked ALTERNATIVE
1, etc. and they are given in the order preferred by us. In a few sections
there are a large number of actual alternatives, so rather than make small
changes and completely rewrite them, a phrase marked (or "...") is added
to denote an alternative wording. When the choice must be made by you, we
insert (N ) for a number or (insert proper agency) or (Environmental
Protection Agency) to indicate other choices are required. When there is
wording that is optional, i.e., we have no strong preferences, these words
are enclosed in a bracket, e.g., [Such as the level that is exceeded for
54 minutes in one hourQ . At the bottom of each section is a statement,
e.g., "(Definitions 1, 14 required)" which states the definitions from
Section 3.2 that must be included if this section is going to be used in
the ordinance. Those same words which are defined are subscripted (Dj)
in the text of the ordinance component to indicate those words whose
definitions should be known before the ordinance component can be
thoroughly understood.
Below each section are paragraphs marked "Discussion:" and, in some
places, they are inserted ahead of the ordinance section and marked "General
Discussion:". These discussions: (1) explain the meaning of the provisions;
(2) explain how it relates to other provisions; (3) provide any necessary
supportive data; (4) cover similar provisions in existing ordinances; and
(5) provide references for review by the reader.
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EXAMPLE
Section number-^. Title
6.2.10 Places of Public Entertainment
Preferred Alternative
ALTERNATIVE
tive^
i
Recommended provision-^ ^-Definition from Section 3.2.15
_/ any motor vehicle (D-^)
Operating or pexmitting to be operated^ which
produces maximum sound levels of (x) dB(A) at any (exteriorl point ...
C ^ V
v—¦ number to be chosen by community ^.optional
¦Definitions from Sections 3.2.1, 3.2.20, 3.2.28, and 3.2.30 must be
inserted.
(Definitions 1, 20, 28, 30 required)
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CHAPTER 7: ORDINANCE COMPONENTS
ARTICLE I SHORT TITLE -
7-12
ARTICLE II DECLARATION OF FINDINGS
7-12
General definition of the need for the ordinance.
Important in establishing legal basis for ordinance.
To provide a list of definitions and standards
that are as technically and legally correct as
possible. Only those definitions which pertain
to the sections chosen need to be used. The defi-
nitions required are listed at the end of each
\
section or subsection of the basic ordinance, and
also superscripted in the text of the ordinance
component.
ARTICLE III DEFINITIONS AND STANDARDS
7-13
Section 3.1 Terminology and Standards
7-13
7-1
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7-2
Section 3.2 Definitions 1 7-14
3.2.1 A-weighted Sound Pressure Level 7-14
3.2.2 Ambient Sound Level 7-15
3.2.3 Commercial Use District 7-16
3.2.4 Continuous Sound 7-17
3.2.5 Cyclically Varying Sonne1 7-18
3.2.6 Day-Night Average Sound Level 7-19
3.2.7 Decibel 7-19
3.2.8 Device 7-19
3.2.9 Dynamic Braking Device 7-20
3.2.10 Emergency Work 7-20
3.2.11 Emergency Vehicle 7-21
3.2.12 Fluctuating Sound 7-21
3.2.13 Impulsive Sound - 7-22
3.2.14 Industrial Use District 7-23
3.2.15 Motor Vehicle 7-23
3.2.16 Muffler — 7-24
3.2.17 Ninetieth Percentile Sound Level 7-25
3.2.18 Noise 7-26
3.2.19 Noise Disturbance 7-26
3.2.20 Person 7-27
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7-3
3.2.21 Plainly Audible Sound - 7-27
3.2.22 Powered Model Vehicles 7-28
3.2.23 Property Boundary 7-28
3.2.24 Public Right-of-way 7-29
3.2.25 Public Space 7-29
3.2.26 Pure Tone 7-29
3.2.27 Residential Use District 7-30
3.2.28 RMS Sound Pressure 7-31
3.2.29 Sound 7-31
3.2.30 Sound Level Meter 7-31
3.2.31 Sound Pressure 7-32
3.2.32 Sound Pressure Level 7-32
3.2.33 Sound Power 7-34
3.2.34 Sound Power Level 7-34
3.2.35 Stationary Sound Source 7-35
3.2.36 Steady Sound 7-35
3.2.37 Tenth Percentile Sound Level 7-36
3.2.38 Vibration 7-36a
3.2.39 Vibration Perception Threshold 7-37
3.2.40 Watercraft 7-38
3.2.41 Weekday 7-38
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M
ARTICLE IV AGENCIES - 7-39
To define the agencies that will be responsible
for enforcement.
Section 4.1 Environmental Protection Office 7-39
Section 4.2 Departmental Actions 7-39
Section 4.3 Departmental Cooperation 7-39
Section 4.4 Compliance with other laws 7-40
Section 4.5 Project Approval 7-41
Section 4.6 Right of Review 7-41
Section 4.7 Contracts 4.8 Low Noise Emission Products 7-42 7-43
ARTICLE V AUTHORITY AND DUTIES 7-45
To define the powers and duties of the primary
enforcement agency
Section 5.1 Powers of Environmental Protection Office 7-45
5.1.1 Studies 7-45
5.1.2 Education 7-45
5.1.3 Coordination and Cooperation 7-47
5.1.4 Project Reviews 7-48
5.1.5 Inspections 7-48
5.1.6 Records 7-49
5.1.7 Measurements 7-49
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7-5
Section 5.2 Duties of Environmental Protection Office 7-50
5.2.1 Measurement Standards 7-50
5.2.2 Truck Routes 7-50
5.2.3 Enforcement Procedures 7-50
5.2.4 Enforcement of Federal Regulations 7-50
5.2.5 Long Term Noise Reduction Goals 7-51
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7-6
ARTICLE VI NOISES PROHIBITED 7_5;
Section 6.1 General Prohibitions 7_5;
General nuisance provision to cover all
possible causes of noise disturbance.
Easy to state, difficult to prove in
court - a backstop to any severe cases
not covered by Section 6.2, or Articles VIII, IX, and X
Section 6.2 Specific Prohibitions 7_53
Specific nuisance provisions to cover
specific causes of noise disturbance.
Where possible, sound level limits are
given; they are somewhat more precise,
less difficult to prove in court, and are
to be used in preference to Section 6.1,
and serve as a backstop for severe cases
not covered in Articles VIII, IX, and X.
6.2.1 Horns and Signalling Devices 7-54
6.2.2 Radios, Television Sets, and Similar Devices - 7-55
6.2.3 Exterior Loudspeakers 7-57
6.2.4 Street Sales - 7-61
6.2.5 Animals 7-62
6.2.6 Loading Operations 7-65
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7-7
6.2.7 Construction Noise 7_66
6.2.8 Vehicle Repairs or Testing 7_70
6.2.9 Aircraft Operations 7_70
6.2.10 Places of Public Entertainment 7_72
6.2.11 Impulsive Sources 7_78
6.2.12 Motor Vehicle Racing Events 7_79
6.2.13 Powered Model Vehicles 7-80
6.2.14 Dynamic Braking Devices 7-82
6.2.15 Refuse Compacting Vehicles 7_83
6.2.16 Standing Motor Vehicles 7-85
6.2.17 Vibration 7-86
6.2.18 Bells and Alarms 7_88
6.2.19 Fixed Sirens, Whistles, and Horns 7-91
6.2.20 Watercraft - 7-92
6.2.21 Quiet Zones 7-94
6.2.22 Domestic Power Equipment 7-95
ARTICLE VII EXCEPTIONS AND PERMITS 7-98
Section 7.1 Emergency Exception 7-98
General provision to make legal the necessary
noise from emergency work or vehicles.
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7-8
Section 7.2 Permit Issuance 7-100
To allow issuance of permits for cases
where social value of event outweighs need
foi noise control.
Section 7.3 Exemptions for Time to Comply 7-101
To allow relief, by issuance of a temporary exemption for
cases where noise control is unreasonable or
unduly restrictive.
RECEIVING
ARTICLE VIII SOUND LEVELS BY/LAND USE 7-104
Section 8.1 Maximum Permissible Sound
Levels 7_104
Intended to control the noise generated
continuously by stationary sources of noise
which is propagated across property boundaries.
Section 8.2 Duration Correction 7-126
Intended to permit the limits set forth
in Section 8.1 to be exceeded for noise sources of
fluctuating or non-continuous character.
Section 8.3 Correction for Character of Sound—. 7-131
Intended to be more stringent on sources of
tonal, cyclically varying, or repetitive
impulsive noise.
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7-9
ARTICLE IX MOTOR VEHICLE SOUND LEVELS - - 7-133
Section 9.1 Maximum Permissible Motor Vehicle 7-133
Sound Levels
Intended to limit the maximum passby noise
from motor vehicles on public rights-of-way.
Enforcement methods for moving sources of
noise must of necessity be different than
that for stationary sources and so the
ordinance provisions must be written separately.
9.1.1 Measurement Distance 7-146
The measurement distance must be cited within
the ordinance since the sound level varies with
the distance from the source. Other measurement
practices such as consideration of wind velocity,
reflecting surfaces, microphone height, temperature,
and atmospheric pressure should not be included in
the ordinance but should be described more fully in
an operational manual.
9.1.2 Truck Routes - 7-153
To restrict truck noise and allow noise sensitive
people to separate themselves from this most severe
source of vehicle noise.
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7-10
Section 9.2 Maximum Permissible Sound Levels
for Vehicles Operating off Public
Rights-of-Way 7-150
Intended to control the noise from off road
vehicles and motorboats, whether registered
or not.
9.2.1 Measurement Distance 7-153
ARTICLE X BUILDING SOUND LEVELS 7-154
Intended to set acoustical standards for the
construction of new buildings. This Article
is presently blank.
ARTICLE XI LAND USE - - - 7-155
Section 11.1 Residential Land Use 7-156
To control construction of residences
in noise impacted areas.
Section 11.2 Commercial or Industrial Land Use 7-160
To assure that new commercial or industrial
development will be in compliance with the
provisions of the ordinance.
Section 11.3 Road Construction 7-161
To control the development of major thoroughfares
to lessen the noise impact on existing residences.
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7-1 la
Section 11.4 Road Building
7-161
No new road construction or modifications
to existing roads will be approved unless
the construction operations are in compliance
with the provisions of this ordinance.
No zoning change, adjustment, variance,
or exception, which affects the land use
categories, will be permitted unless the
use to be allowed does not violate the
provisions of this ordinance.
No person shall sell or rent, or cause
to be sold or rented, any structure to
be used for habitation, outside of which
structure the sound levels are in excess
of those permitted under this ordinance,
without making full disclosure to all
potential buyers or renters of the
existence of such noise disturbance.
Section 11.5 Zoning Changes
7-162
Section 11.6 Truth in Selling or Renting
7-162
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7-lib
ARTICLE XII ADDITIONAL PROVISIONS 7-168
Section 12.1 Penalties 7-168
To allow for penalties. Will vary with
locality.
Section 12.2 Additional Remedy-Injunction 7-169
To provide for immediate relief from
noise disturbance.
Section 12.3
Section 12.4 Contracts - -7-172
To make the community government responsive
to their own noise ordinance by requiring
community contractors to obey the ordinance.
Section 12.5 Low Noise Emission Products - 7-174
To insure that certified low noise emission
products are given preferential procurement
by the municipality.
Section 12.6 Method of Enforcement 7-175
To make explicit when summons and complaints
are mandatory and to set enforcement policy.
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7-llc
ARTICLE XIII SEVERABILITY - 7-177
To prevent an entire ordinance from being
invalidated if one or more sections are
found invalid.
REFERENCES - 7-178
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7-12
ARTICLE 1 SHORT TITLE
This ordinance may be cited as the "Noise Ordinance
of the City of "
Discussion: This statement in a community noise ordinance
is probably not necessary but is included for completeness
and for consonance with legislation recommended for states
by the Council of State Governments.
ARTICLE II DECLARATION OF FINDINGS AND POLICY
ALTERNATIVE 1
WHEREAS excessive noise is a serious hazard to the public
health and welfare and the quality of life; and
WHEREAS the people have a right to and should be ensured an
environment free from noise that may jeopardize their health or
welfare or degrade the quality of life; and
NOW, THEREFORE, it is the policy of the City of
to prevent noise which may jeopardize the health or welfare of
its citizens or degrade their quality of life.
ALTERNATIVE 2
WHEREAS, the making and creation of excessive or un-
usually loud noises within the limits of the City of
is a condition which has existed for some time, and the extent
and magnitude of such noises is increasing; and
WHEREAS, the making, creation, or maintenance of such
excessive or unusually loud noises which are prolonged, unusual,
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7- 12a
or unreasonable in their time, place, and use, affect, and
are a detriment to, public health, comfort, convenience,
safety, and welfare of the residents of the City of ;
or may cause damage to property or business; and
WHEREAS, the necessity in the public interest for the
provisions and prohibitions hereinafter contained and enacted,
is declared as a matter of legislative determination and public
policy and the provisions and prohibitions hereinafter contained
and enacted are in pursuance of and for the purpose of securing
and promoting the public health, comfort, convenience, safety,
welfare, and the peace and quiet of the inhabitants of the
City of
Discussion: Alternative 1 is a more recent streamlininq of
Alternative 2 and is contained in the Council of State Governments,
Model State Noise Code, Section 102 (Ref. 9). It contains only
those elements found to be important in establishing the reason
for an ordinance. Alternative 2 is the most common type found
in municipal noise ordinances.
The word "unnecessary" has been deleted in
Alternative 2 because proving necessity may be a difficult
thing and the intent of the law is to prevent excessive noise
only, and technology is available today to prevent excessive
noise where many years ago it was not.
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7-13
ARTICLE III DEFINITIONS AND STANDARDS
Section 3.1 Terminology and Standards
All terminology used in this ordinance and not
defined below, shall be in conformance with
applicable publications of the American
National Standards Institute (ANSI) or its
successor body.
-------
7-14
Discussion: The American National Standards Institute,
which does not represent any particular industry group,
has developed some standards that relate to acoustics and
acoustical measurements. Their definitions are generally
more scientifically oriented and are not always applicable
See Chapter 3 for example,
to noise ordinance enforcement./ Thus, the above statement
gives precedence to the definitions in the ordinance. A
complete set of useful definitions is necessary in an
applicable
ordinance until such time as an/ANSI document is issued.
Other societies have developed standards, some blatantly
self-serving, others not.
Section 3.2 Definitions
General Discussion: We recommend that certain of the definitions
below be included in any noise ordinance. These basic definitions
are 3.2.1, 2, 7, 8, 10, 11, 18, 19, 20, 27, 28, 29, 30, & 31.
3.2.1 A-weighted Sound Level (Sound Lave I) means
the sound pressure level in decibels as measured on a
sound level meter using the A-weighting network.
The level so read shall be designated dB(A) or
dBA.
-------
7-15
Discussion: This weighting is the most preferred, both
in ordinances and by experts in community noise, and its
use is strongly recommended. See discussions in Articles
VIII and IX for uses, and discussion section C of Section
8.1 for a detailed explanation.
3.2.2 Ambient Sound Level Means
The sound level of the all encompassing
sound'' associated with a given environment, being
usually a composite of sounds from many sources.
The A-weighted sound level exceeded 90
percent of the time based on a one-hour period.
Discussion: The first part of the definition is similar to
others found in many scientific documents and in some noise
ordinances. It cannot be used in the field as a criterion
for defining ambient noise quantitatively. Although the
components in this chapter are drafted in such a way that
reliance on ambient noise measurements is minimized, there
will be occasions on which such measurements will be advisable.
One situation is when the "ambient" level exceeds the legal
limit and hides the potential noise violator. The problem
that remains is how to define "ambient" in the field.
Deciding whether a potential noise violator should be in-
cluded in the ambient is one sub-problem and the means for
measurement of the ambient is another.
-------
7-16
Palo Alto (Ref. 52) excludes the noise vMlator and defines
"local ambient" as "the lowest sound level repeating itself
during a six-minute period as measured with a precision) sound
level meter using slow response and "A" weighting." EPA
(Ref. 53) defines a "residual noise level" as "... the noise
which exists at a point as a result of the combination of many
distant sources, individually indistinguishable. In statistical
terms, it is the level exceeded 90 percent of the time." The
second part of the above definition is the same as this our "ambient"
level, with the exception that we include a measurement period.
For a continuous but fluctuating noise source, a 10-minute sample
is adequate, but if the source is intermittent or the con-
sequences of the measurement may result in the expenditures of
millions of dollars a longer sample period is recommended. The
Palo Alto definition is one working definition of the 90th per-
centile levels and for discussion of these levels refer to
Section 3.2.17. We recommend that no mention of any potential
noise violator be included in the definition so
the definition can be used for monitorinq as well as noise source
regulation; this will provide no handicap in enforcement.
3.2.3 Commercial Use (District, Zone) means
(Local definition required)
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7-17
3.2.4 Continuous Sound-means
any sound which exists, essentially
without interruption, for a period of
(one hour) or wore.
Discussion: Continuous noise is an additional definition
to aid in practical enforcement matters. It is usually
considered to be the same as steady noise in scientific
literature but must be distinguished from it here for
reasons set forth in Articles VI and VIII (see definition
3.2.36 for steady noise). There are several important
factors that contribute to annoyance. The first is loud-
ness or sound pressure level which can be measured on a
sound level meter. (See Chap 3) The second is time history or duration
which can be measured on several time scales. The scale of
one second or less is used to provide sound level meter time
averaging to get the sound pressure level we read and to dis-
tinguish impulsive noise and also pure tones from the other types.
On the scale of minutes we can distinguish between sounds that
are steady, fluctuating, or repetitive. The scale of hours can
be used to determine whether sounds are continuous or noncontiguous
Annoyance and complaints are based on these three time scales.
A repetitive impulsive sound that persists for several hours
(pile driving) has three bases for complaint beside the sound
level: it is impulsive (scale of seconds)"; " iY'is'repeate'd Tt
reasonably uniform
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time intervals (scale of minutes), and is a continual noise
intrusion extending over several hours. The definition above
is aimed toward the more persistent (continuous) noise sources,
the other definitions relate to the other time scales.
Figure 7-la shows two examples of continuous noise. The
choice of time scale is important and may determine how long
an EPO needs to be out making a measurement. See Article VIII
for use of this definition.
3.2.5 Cyclically-Varying Sound means
any sound which varies in sound
level such that the same level
is obtained repetitively at
reasonably uniform intervals of
time.
Discussion: This definition is complimentary to "Pure Tone"
given in Section 3.2.25. A pure tone or set of
tones can be heard as a repetitive phenomenon by the ear but
the sound level meter may record a steady level because the
fluctuation is too rapid for the meter to follow it, i.e.,
the meter averages over the fluctuation. A slower repetitive
phenomenon is that associated with impulsive noises such as a
stamping operation; the ear can clearly detect the repetitions
but the sound level meter may or may not follow the impulses.
An even slower repetitive phenomenon we call cyclically varying
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7-19
sound; the time scale is minutes and the sound level meter
can follow the changes. Examples are cycling of air conditioners
or construction air compressors. For visual descriptions of these
noises, see Figures 7-1 on pages and . For application of
these definitions, see Section 8.3.
3.2..6 Day-Night Average Sound Level means
A 24-hour average of the A-weighted sound
level, with the level during the period
10 p.m. to 7 a.m. increased by 10 dB(A)
before averaging. It is denoted L
dn
Discussion: The noise measure is very helpful in defining
the noise environment on a daily average basis for olanninci
purposes, especially with regard to preventing deterioration
in the future. See discussion in Chapter 3 for explanation
and use of this descriptor.
3.2.7 Decibel means
a logarithmic and dimensionless unit of measure
often used in describing the amplitude of sound.
Decibel is denoted as dB.
Discussion: See Section 3.4 of Chapter 3 for an explanation of dB.
3.2.8 Device means
any mechanism which is intended to produce, or
which actually produces, noise when operated
or handled.
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7-20
3.2.9 Dynamic Braking Device means
a device used, primarily on trucks, to
convert the motor from an internal
combustion engine to an air compressor
for the purpose of vehicle braking.
Discussion: By changing the timing of the engine valves, the
engine on a vehicle can be converted to an air compressor. The
air compression process absorbs power from the rear driving
wheels instead of the usual supply of power to the wheels, and
thus acts to reduce vehicle speed. Piston pressures are high
in this mode of operation and discharge valve opening results
in shock waves that produce intense repetitive sounds much
like that of a machine gun. The initiation of dynamic braking
is under the control of the driver and it can be used or misused
at his discretion. It is a very necessary device in mountainous
country. Unfortunately, many truck mufflers are not designed to
quiet these devices, so some form of control is necessary. See
Section 6.2.14 for use ofthis definition (page 7-84).
3.2.10 Emergency Work means
work made necessary to restore property to
a safe condition following a public calamity,
work to restore public utilities, or work
required to protect persons or property from
an imminent danger.
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7-21
3.2.11 Emergency Vehicle means
a motor vehicle used in response to a
(public) calamity or to protect persons
or property from imminent danger.
3.2.12 Fluctuating Sound means
any sound which
varies more than 6 dB(A) during the period
of observation when measured with the slow
characteristic of a sound level meter,
and does not equal the previously existing
ambient noise level more than once during the
period of observation.
Discussion: A fluctuating noise is best exemplified by music.
Music is certainly not a steady sound, and with an ordinary
sound level meter used in the normal way it would be difficult
to assign a sound pressure level to it except for the maximum
observed. Although the maximum observed sound level can be and
has been used in noise regulation, it can be an unreasonable
restriction on activities that produce high peak levels on rare
occasion. For fluctuating noise sources, it is more reasonable
to apply 'percentile levels. See Sections 3.7 for a detailed
discussion. of fluctuating srunds.
The 6 dB(A) limit, to distinguish between steady and fluctuating
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7..?2
noise, is taken from the American National Standards Institute
publication S 1.13-1971. That number has meaning in the field;
if the noise is "steady" one can use the methods of the above
document to closely estimate the average sound level by directly
observing the sound level meter. This definition and its complement
in Section 3.2.35 on page3-9 may not Be used 1n the ordinance
itself, but they will be used in practice.
3.2.13 Impulsive Sound Means
ALTERNATIVE 1
a sound containing excursions, usually less
than one second, of sound pressure level
20 dB(A) or more over the ambient sound
level, using the fast meter
characteristic.
ALTERNATIVE 2
a sound characterized by brief excursions
of sound pressure whose peak levels exceed
the ambient by (N ) dB. The duration of a
z
single impulse is usually less than one
second and requires the use of a sound level
meter specially adapted for its measurement.
-------
7-23
Discussion; An impulsive sound is either the sound of an
impact, such as a hammer strike or the sound of an explosion
such as blasting. In both groups the sound reaches high peaks
very quickly. Water hammer and the sonic boom are also
impulsive noises.
Alternative 1 defines impulsive sound so that
an EPO in the field can use an ordinary sound level meter
to determine whether a sound is impulsive or not. The peak
level read on the meter will be low, so if an allowance of
20 dB(A) is given, the sound most definitely would be impulsive.
The definition would exclude any impulsive sounds that occurred
so close together the meter could not follow them.
Alternative 2 is recommended for larger communities
that can afford the additional expense of an impulse sound level
meter. The correct levels can be read, but the value of (Nz)
must be chosen locally.
3.2.14 Industrial Use (District, Zone) means
(local definition required)
3.2.15 Motor Vehicle means
ALTERNATIVE 1
as defined in the motor vehicle code of the
State of
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7-2*
ALTERNATIVE 2
any vehicles propelled by mechanical
powerf such as, but not limited to, any passenger car, truck,
truck-trailer, semi-trailer, camper, motorcycle,
minibike, go-cart, snowmobile, amphibuous
craft on land, dune buggy, or racing vehicle,
Discussion: The first alternative restricts the definition to
licensed motor vehicles and generally includes off-highway types
as well, if licensing is required by your state. The latter
definition is more inclusive and allows noise limits to be
applied to all forms of powered transportation equipment,
whether licensed or not. The latter definition may have to be
modified to be consistent with state law. Article IX makes
extensive use of these definitions.
3.2.16 Muffler means
any apparatus consisting of baffles, chambers,
or acoustical absorbing material whose primary
purpose is to transmit liquids or gases while
causing a reduction in sound emission at one end.
To qualify, such an apparatus must cause a reduction
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7-25
in sound pressure level of at least
(Nz) dB(A) upon insertion into the
system for which it is intended.
Discussion: The definition must be in conformity with
applicable definitions in the appropriate state laws, although
many states have very poor definitions. The second sentence
of the definition will permit a workable definition of a muffler
to be given. The value of "Nz" must be chosen by the community.
If it is set less than 10 dB(A), any tin can may be placed on the
discharge of a machine and be called a muffler. This definition
is intended for use with the general muffler provisions found
in most existing ordinances.
3.2.17 Ninetieth Percentile Sound Level means
the A-weighted sound level that is
exceeded ninety percent of the time in any
measurement period (such as the level that is
exceeded for 54 minutes in one hour) and is
denoted L
90
Discussion: This measure is intended to determine the base noise
levels (the chronic noise exposure). Sometimes these levels are
caused by a particular continuous sound source and sometimes by
the total collection of sources. The difference between l_1Q and
-------
7-26
L helps to measure the deqree of intrusiveness of community
noise sources. For a general explanation of percentile levels
and how to measure them, see Section 3.7 of Chapter 3 and, for an
explanation in the context of its use, see discussion Section G of
ordinance Section 8.1. See Section 3.2.2 for the use of Lgg in
the definition of ambient noise level.
3.2.18 Noise means
any sound which is unwanted or which causes,
or tends to cause, an adverse psychological
or physiological effect on human beings.
Discussion: This definition includes two definitions, the
first part requires the cooperation of the listener. The
second part does not; it is based on the collective experience
of society in evaluating the health and welfare effect on noise
(See Chapter 4).
3.2.19 Noise Disturbance means
any sound which annoys, disturbs, or perturbs
reasonable persons with normal sensitivities;
or any sound which injures or endangers the
comfort, repose, health, welfare, hearing,
peace, or safety of other persons.
Discussion: This definition overlaps the definition of noise
in Section 3.2.18 somewhat, but is intended as a working definition
for use in answering noise complaints where definition 3.2.18
is difficult to use. It is used in Article VI to define the
nuisance associated with any disturbance caused by noise.
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7-27
3.2.20 Person means
any individual, association, partnership, or
corporation, and includes any officer, employee,
department, agency, or instrumentality of the
United States, a state or any political sub-
division of that state.
3.2.21 Plainly Audible Sound means
any sound for which the information content
of that noise is unambiguously communicated
to the listener, such as, but not limited to,
understandable spoken speech, comprehension
of whether a voice is raised or normal, or
comprehensible musical rhythms.
Discussion: One major type of complaint is due to
the neighbors that cause a noise disturbance across property
boundaries. This definition, which is coupled with Section 6.2.2
of the ordinance, is an attempt to establish the degree of noise
intrusion without the use of a sound level meter. Acoustical
privacy is what is desired and the communication of information
by sound breaks that privacy. The transient nature of the sound
makes it difficult to measure, so the more descriptive identification
ahnve is helpful. In addition, this definition allows
a noise control officer to establish the probability of a violation
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7-28
by asking questions over the telephone. For applications
see discussion under Section 6.2.2 on page 55 .
3.2.22 Powered Model Vehicle means
any vehicle which can be propelled by
mechanical means, either airborne, water-
borne, or landborne, which is designed not
to carry persons or property; such as, but
not limited to, model airplanes, boats, cars,
rockets.
Discussion: With the development of larger and faster model
vehicles, noise intrusion from their operation, usually in
open fields or parks, can be severe. This definition is
intended to separate a model vehicle from a vehicle which
can be used for more than recreational purposes. See Section
6.2.13 on page 80 for the applicable ordinance section.
3.2.23 Property Boundary means
an imaginary line exterior to any enclosed
structure, at the ground surface, and its
vertical extension, which separates the real
property owned by one person from that owned
by another person.
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7-i!y
Discussion: In most instances, measurements at or near
ground level are adequate. This definition extends the
line vertically to account for rooftop noise sources
bothering residents in opposing buildings. Measurements
cannot be made there normally but that is taken care of
in the ordinance component. The part concerning an
exterior line, specifically excludes noise problems
associated with condominiums or contiguous buildings
which are more properly included in building codes.
3.2.24 Public Right-of-Way means
any street, avenue, boulevard, highway, or
alley or similar place
which is owned or controlled by a public
governmental entity.
3.2.25 Public Space means
any real property or structures, other than a public right-of-
way ,
which is owned or controlled by a
governmental entity.
3.2.26 Pure Tone means
any sound which can be distinctly heard as a
single pitch or a set of single pitches. For
the purposes of measurement, a pure tone shall
exist if the one-third octave band sound pressure
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7-30
level in the band with the tone exceeds the
arithmetric average of the sound pressure
levels of the two contiguous one-third octave
bands by 5 dB for frequencies of 500t}z and
above and by 8 dB for frequencies between 160
and 400 Hz and by 15 dB for frequencies less
than or equal to 125 Hz.
Discussion: The extensive use of pure tone: corrections in
noise ordinances can create measurement problems. In this recom-
mended ordinance it appears only in Section 8.3. In most enforce-
ment situations, the presence or absence of a tone can be determined
with the ear and the first part of the above definition is written
to accommodate this fact. In cases where it is more doubtful or
in which there is a contest, the second part of the definition
can be used to precisely define the presence of a tone. It does
require the use of a 1/3 octave band analyzer, which can be
expensive. Because of this expense, it may be more feasible to
tape record the sound and allow a court to determine aurally the
presence of a tone. We have no knowledge whether this latter method has
been tested successfully to date.
3.2.27 Residential Use (District, Zone) means
(Local definition required)
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7-31
3.2.28 RMS Sound Pressure means
the square root of the time averaged
square of the sound pressure, denoted
Prms.
Discussion: Since the average value of the sound pressure is
the barometric pressure, it is not possible to use straight
"voltages that areiaveraging as a measurement method. A sound level meter squares
„ generated by the/ —
the souncrf>ressure so all phases are positive and then averages
to get a value different from the straight average. To counter-
act the squaring, the square root is taken yielding a D.C. voltage
which is slightly less than the maximum A.C. voltage that occurs
at the microphone. This method of measurement is used for all
forms of fluctuating signals (See Figure 7-2 for graphical
interpretation' and the discussion in Section 3.3 of Chapter 3).
3.2.29 Sound means
a temporal and spatial oscillation in pressure,
or other physical quantity, in a medium with
internal forces that causes compression and rare-
faction of that medium, and which propagates at
finite speed to distant points.
3.2.30 Sound Level Meter means
an instrument, including a microphone, amplifier,
RMS detector and integrator, or time averager,
output meter and weighting networks, that is
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7-32
sensitive to pressure fluctuations.
The output meter reads sound pressure
level when properly calibrated and the
instrument is of Type 2 or better as
specified in American National Standards
Institute Publication SI.4-1971, or its
successor publication.
Discussion: Sound level meters all contain the basic elements
listed in the first sentence, but the quality of these elements
and, therefore, their cost can vary. The second sentence
establishes a standard which eliminates sound level meters
that are not accurate enough for regulatory work. The highest
quality and most expensive meter is Type 1; Type 2 is less good
and less expensive but still acceptable for regulatory work,
including providing admissible evidence in court. Type 3 is
not considered sufficiently accurate for regulatory use by an
EPO.
3.2.31 Sound Pressure means
the instantaneous difference between the
actual pressure and the average or barometric
pressure at a given point in space due to sound.
3.2.32 Sound Pressure Level means
20 times the logarithm to the base 10
of the ratio of the RMS sound pressure
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7-33
Lj
a~
501) Kb j *
\
Linrt
u
cJ
g fyrtV;
rv
Ci
^ ftTh0^
Si
(Y-
SOU8t> S^oftteD , p
L(m£
ME Ft M P££6*o0fc£ SqdfcffcD^ t>
/
\.y
i^vl
7 r
¦> IlMt
Root mean ^oomd pres^ee.
(F - prni»
I Ifrv*- inW\£^
Kt>S ^T(Vr\ I
FIGURE 7-2. SIMPLIFIED OPERATION OF SOUND LEVEL METER TO GET RMS SOUND PRESSURE
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7-34
to the reference pressure which shall
be 20 micropascals, denoted L or SPL.
P
Discussion: Note that the word "level" is used when the
decibel is applied to the measurement of a physical quantity.
See Section 3.5 of Chapter 3 and Definition 3.2.7. This.is
the number that appears on tie face'of a sound level meter. See Section 3.5
of Chap 3 and Definition 3.2.7
3.2.33 Sound Power means
the total work per unit time done on the surrounding
medium by the sound from a source.
Discussion: Sound power is only a very small part of the
total power used by a device. The loss due to sound emission
is so small it cannot be measured at the source and must be
measured at a distance with a sound level meter. This definition
is meant to be used with Article X.
3.2.34 Sound Power Level means
10 times the logarithm to the base 10
of the ratio of the sound power to the
-12
reference power which shall be 10
watts; denoted Lw or PWL.
Discussion: L is the logarithmic and dimensionless measure of
sound power, hence the word "level" again. Sound level meters
cannot measure Lw but, under certain circumstances, it can be
calculated from sound pressure level measurements. It is to be
used in conjunction with Article X.
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7-35
3.2.35 Stationary Sound Source means
any device, fixed or movable, which is located
or used on property other than a public right-of-way.
Discussion: The above definition uses the word "stationary"
in a different sense from the words "fixed" or "property line"
found in other ordinances. Sources moving on a public right-of-way
cause only one noise intrusion for a reasonably short time interval,
but a stationary noise source will make continual noise intrusions
and can be attributed toa neighbor. The recent advent of mini-
bikes and the like, give rise to noise intrusions from vehicles
moving within a property boundary. It is recommended that they
be considered stationary noise sources and thus be subject to
Article VIII of this ordinance, when they operate on private
or public property. If you try to get within 50 feet for a
vehicle-type measurement, they will be long gone. This would
not restrict the use of Article XI on page 155 for motor vehicles;
it could be used in addition. However, they should not necessarily
have to meet the standards of a motor vehicle if the property is
so large they can cause no annoyance even if unmuffled. It would
unduly restrict the use of one's property. Article VIII makes
use of the above definition.
3.2.36 Steady Sound means
a sound pressure level which remains essentially
constant during the period of observation, i.e.,
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7-35a
the fluctuations are too small to
meet the criterion for fluctuating
sound.
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7-36
Discussion: It is standard practice to lump "steady" sound
with "continuous" sound in scientific documents. For regu-
latory purposes, continuous sound relates to duration and
steady sound relates to the ease of measurement. See Section
3.2.4 on page for a discussion of continuous sound and
Section 3.2.12 on page for a discussion of fluctuating
sound and the difference between it and steady sound. See
also Figures 7-1 on pages 17~a, b,~and c for a visual description
of the various types of sound. To establish nuisance»the
duration or continuity of the sound is important, but a
fluctuating sound is generally more annoying than a steady
sound. These two separate concepts require separate
definitions.
3.2.37 Tenth Percentile Noise Level means
The A-weighted sound level that is exceeded
ten percent of the time in any measurement
period [sucft as the level that is exceeded
6 minutes in one hour I is denoted L
-J 10
Discussion: This measure is intended to determine the intensity
of the louder noise intrusions (the acute noise exposure) which
are the primary disruptions to our acoustical environment. It
can be measured relatively simply and is helpful for assessing
the impact of transportation noise. The difference between
Ljg and Lgg helps to measure the degree of intrusiveness of
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7-36a
community rioise sources. For a more complete explanation,
in the context of its use, see discussion Section G of
ordinance Section 8.1 on page 104 .
3.2.38 Vibration means
a temporal and spatial oscillation of
displacement, velocity or acceleration
in a solid material.
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7-37
Discussion: Vibrations can occur in any physical material
including air. This definition restricts itself to the
common usage of pertaining only to solid materials.
3.2.39 Vibration Perception Threshold means
The minimum vibrational motion necessary
to cause awareness of its existence on
the part of a normal person, by direct
means, such as, but not limited to,
sensation by touch or visual observations
of moving objects. For the purpose of this
ordinance, the perception threshold shall
be presumed to be 0.05 in/sec RMS vertical
velocity.
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4 7 10 3D 40 70 loo J6&
FPEQUEKW HEPHZ
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7-38
3.2.40 Week day means
any Monday, through
Friday which is not a legal holiday.
Discussion: For the purpose of taking reference sound levels
for site evaluation, it is necessary to avoid the possibility
of obtaining data during times when the traffic is excessively
heavy or light. By taking an average over a typical working day,
the data are more likely to represent the noise climate most
often experienced throughout the year. See Article XI for
use of this definition.
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7-39
ARTICLE IV AGENCIES
Section 4.1 Environmental Protection Office
The noise control program required by this ordinance
shall be administered by the Environmental Protection
or Noise Controdj Office.
Discussion: For small communities, an Environmental Protection
Officer (EPO) is recommended. He will administer all environmentally
related programs, including noise. For larger cities an Environmental
Protection Office with a Noise Control Officer is recommended. He
should not be a member of the Police Department. See also Question
1.5 in Appendix for discussion of the reasons for this recommendation.
Section 4.2 Departmental Actions
All departments shall, to the fullest extent
consistent with their authority under ordinances
administered by them, carry out their programs
in such a manner as to further the policy stated
in Article II of this ordinance.
Discussion: This section establishes the intent of the City Council
to have all departments within the municipality accept responsibility
for noise control. This statement coupled with Section 4.3 below will
provide the support needed for an effective noise control program.
Section 4.3 Departmental Cooperation
All departments shall cooperate with the (Environmental
Protection £Noise Control"] Officer) to the fullest
extent in enforcing the noise regulations of this
ordinance.
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7-40
Discussion: Cooperation of other departments, particularly
the police, fire, planning and building, is very important.
This section mandates such cooperation and is one of the
more important statements in the ordinance.
Section 4.4 Compliance with other laws
All departments engaged in any activities
which result or may result in the emission
of noise shall comply with Federal and State
laws and regulations, as well as the provisions
of this ordinance, respecting the control and
abatement of noise to the same extent that
any person is subject to such laws and regulations.
Discussion: With the growth of community services, much en-
vironmental noise is emitted from governmental activities such
as street repair, garbage collection, police sirens, official
vehicle loudspeakers, and helicopters. If a noise control
program is to be credible and effective, compliance by the
government itself is necessary. This section would also protect
city employees from having to work in a noisy environment. This
section also represents a waiver of the sovereign immunity of the
city government from the non-application of the ordinance.
Historically, although the law is rapidly changing, all governmental
units were exempt from the application of the tort laws (such as
nuisance law) under the theory that "the King can do no wrong."
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7-41
Hence, this concept is known as "sovereign immunity."
Burgeoning of governmental activities, coupled with this
immunity, may make government the biggest noisemaker in
the future, if it is not already (military aircraft, police
sirens).
Section 4.5 Project Approval
Each department whose duty is to review
and approve new projects or changes to
existing projects that result, or may
result, in the emission of noise, shall
consult with the (Environmental Protection
Qioise Control) Office) prior to any such
approval.
Discussion: Many noise problems can be prevented by good
planning. Noise, as a relatively new environmental problem,
is not normally considered by agencies with other concerns.
This section requires that the agency with the most expertise
in noise be involved with those projects in which noise plays
an important role. One example is the process of approval for
a planned unit development near a very busy freeway. This section
should be tied to Article XI.
Section 4.6 Right of Review
If at any time the XEnvironmental Protection
Qfoise Control) Office) has reason to believe
that a standard, regulation, or action, or
proposed standard, regulation, or action of
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7-42
any department respecting noise
does not conform to the intent of
Article II of this ordinance, he
may request such department to review
and report to him on the advisability
of revising such standard or regulation
to conform.
Discussion: There are times when contemplated regulatory
actions by the community may create adverse environmental
noise impact. This section insures that the EPO will have
his concerns taken into account.
Section 4.7 Contracts
Any written agreement, purchase order, or
instrument whereby the city is committed to
the expenditure of funds in return for work,
labor, services, supplies, equipment, materials,
or any combination of the foregoing, shall not
be entered into unless such agreement, purchase
order, or instrument contains provisions requiring
that any equipment or activities which are subject
to the provisions of this code will be operated,
constructed, conducted, or manufactured without
causing violation of the code.
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7-43
Discussion: This provision is closely modeled after that
for New York City (Ref. 3). San Diego (Ref. 2, Sec. 59.5.0301)
has a section on contracts, but specifically exempts the city
government or any local state or Federal agencies with whom
they have contracts. With this exception, the remainder of
the San Diego provision is worth reviewing. It is recommended
that, in the interest of simplicity, the above provision be used.
There are a number of municipality-related operations
which can cause severe noise impact: street repair, chain sawing,
log chipping, garbage collection, and so forth. Technologically,
most of these sources can be cr trolled to be in compliance with
Article VI or VIII. Article IV requires city agencies to comply
with the ordinance and this provision requires contractors to do
so also.
Section 4.8 Low Noise Emission Products
Any product which has been certified by the
Administrator of the U.S. Environmental Protection
Agency pursuant to Section 15 of the Noise Control
Act of 1972 as a low noise emission product and
which he determines is suitable for use as a
substitute, shall be used in preference to any
other product, provided that such certified product
has a procurement cost which is not more than 125
percentum of the least expensive type of product
for which it is certified as a substitute.
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7-44
Discussion: The enactment of the Noise Control Act of 1972
has provided communities an opportunity to buy quiet products
as soon as the certification procedure described in the provision
above is activated. This section will provide specific guidance
to other agencies of the municipality that are required by Article
IV to comply with the provisions of this ordinance.
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7-45
ARTICLE V AUTHORITY AND DUTIES
Section 5.1 Powers of (Environmental Protection Office)
In order to implement the purposes of this
ordinance, the Environmental Protection Office(r)
shall have the power to:
Discussion: This article and section may not be considered
necessary for your community ordinance by the City Attorney.
However, it is helpful to spell out powers and, if not in the
ordinance, the following sections can be used administratively
to define the powers and duties of the EPO.
5.1.1 Studies
Conduct, or cause to be conducted, studies,
research, and monitoring related to noise.
Discussion: This section establishes the continual need for
program improvement and gives the EPO the power to initiate it.
5.1.2 Education
Conduct programs of public education regarding
the causes and effects of noise, giving general
advice for its abatement, and to encourage the
participation of public interest groups in related
public information efforts.
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7-46
Discussion: Public education, particularly among secondary
school and university students, will be a very important part
of any successful noise control program, as it has with other
programs such as drug abuse. The intent of the noise ordinance
can be implemented properly if the importance of education is
stressed in the ordinance itself, or in some other form of
writing.
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7-47
5.1.3 Coordination and Cooperation
Coordinate the noise control activities of all
municipal departments and cooperate where
practicable with all appropriate municipal,
county, state, and federal agencies to best
implement the policies and purposes of this
ordinance and, where appropriate, enter into
contracts (with the approval of the City Council)
for the provision of technical or enforcement
services.
Discussion: A community noise control program is made simpler
and more effective if neighboring communities also have a noise
ordinance with provisions similar, if not identical, to those of
your community. Cooperation helps to propagate an ordinance, but
in some cases an undue amount of your time can be involved so you
should consider entering into contractual relationships with
neighboring communities. In fact, an EPO could be shared by
several small municipalities that could not afford one singly.
Coordination of inter municinnl programs by the EPO is very
necessary and an ordinance provision to this effect gives the
authority.
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7-48
5.1.4 Project Reviews
Review all projects of any other department that are
subject to review for compliance with
the intent and provisions of this ordinance.
This shall include the review of all licensing
applications where noise may be an important
factor.
Discussion: The internal control of municipal projects or
permits is a very important aspect of a noise control
ordinance. In small communities, the various departments
have individuals known to one another and internal cooperation
is more likely to occur so the right of review may not be
necessary to put into the ordinance. In large cities a formal
agreement is probably necessary and the one suggested above
may need to be expanded.
5.1.5 Inspections
For reasonable cause and upon presentation of
proper credentials, enter any building, property,
premises, or place and inspect any noise source
for the purpose of ascertaining the compliance or
non-compliance with any provision of this ordinance,
or have access to, and require the production of,
books and papers pertinent to any matter under investigation.
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7-49
Discussion: Entering premises without a search warrant is
becoming subject to increased scrutiny by the legal profession.
The validity of the provision above is still subject to judicial
interpretation, and your local situation may dictate that other
methods are required.
5.1.6 Records
Require the owner or operator of any noise
source to establish and maintain records and
make such reports as the (Environmental Protection
(Noise Control) Office) may reasonably prescribe.
5.1.7 Measurements
Require the owner or operator of any noise source
to measure the noise emissions thereof in accordance
with such methods and procedures and at such locations
and times as the (Environmental Protection jjVoise Control~j
Office) may reasonably prescribe.
Discussion: These latter sections give the EPO not only the
powers needed to effectively operate his program but also
guidance as to his duties.
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7-50
Section 5.2 Duties of (Environmental Protection Office)
In order to implement the purposes of this
ordinance, the (Environmental Protection
Office) shall be required to:
5.2.1 Measurement Standards
Develop measurement methods and standards which
will further the purposes of this ordinance.
5.2. 2 Truck Routes
Develop a truck route map of the community for
the purpose of minimizing noise exposure caused
by trucks.
5.2.3 Enforcement Procedures
Develop administrative procedures which will
t
provide for effective enforcement of this
ordinance.
5.2.4 Enforcement of Federal Regulations
Make recommendations for changes to this ordinance
so that it is consistent with all preemptive state
and Federal regulations, and provide for effective
enforcement of those changes.
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5.2.5 Long Term Noise Reduction Goals
Develop long term plans and goals to eliminate
the deleterious effects which noise has on the
health and welfare of citizens of ,
develop a generalized noise map of the community
showing noise impacted areas, and develop a means
for incorporating these goals, plans, and data
into the long range planning process.
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ARTICLE VI NOISES PROHIBITED
Section 6.1 General Prohibitions
Jt shall be unlawful for any person to make,
continue, or cause to be made or continued or
caused any excessive or unusually loud noise,
or to create a noise disturbance within the
limits of the City of .
Discussion: This section is the general nuisance provision
commonly found in older noise ordinances. It is vaguely
worded and difficult to prove in court and its use should
only be contemplated when the more specific sections of this
Article or of Articles VIII and IX do not adequately cover
the problem. If the remainder of the provisions in this
workbook are properly incorporated into the ordinance, it is
unlikely that there will be much use for this section.
Variations of this statement can be found in the
NIMLO Model Noise Ordinance (Sec. 8-302 of Ref. 1) in the San Diego
Noise Ordinance (Sec. 59.5.0501 of Ref. 2), in the New York Noise
Ordinance (Art. Ill of Ref. 3), and in the Lakewood Noise Ordinance
(Sec. 9.52.040 of Ref. 4).
NOTE: REQUIRED DEFINITIONS ARE SHOWN IMMEDIATELY
BELOW EACH SECTION OR SUBSECTION.
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Section 6.2 Specific Prohibitions
The following acts, among others, are declared
to be excessive or unusually loud noises or to
create noise disturbance in violation of this
ordinance, but said enumeration shall not be
deemed to be exclusive, namely:
Discussion: The above statement is necessary to validate the
sub-sections below. The specific prohibitions are explicative
of the general prohibition in Section 6.1 and this statement
must be worded in the same way (excessive or unusually loud
noise or to create noise disturbance).
This section is intended to enumerate as many
possible sources of noise as may exist in a community that
are too difficult to measure by the means given in Articles
VIII and IX. The most conrnon example is a barking dog. Each
is enumerated separately below because some are more subject to
quantifiable measures than others, for example, Section 6.2.15
gives a specific numerical limit on the noise from trash compacting
vehicles, where in Section 6.2.5 the barking dogs have no specific
limit. It is important Uo include a specific prohibition for
each noise source in your list of noise sources found in Step 6
of Chapter 2.
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7-54
6.2.1 Horns and Signalling Devices
The sounding of any horn or signalling device
on any motor vehicle on any public right-of-way,
except as a danger warning signal or as provided
in the vehicle code of the State of ,
or the sounding of any such device for an unnecessary
and unreasonable period of time, at any place.
(Definitions 15, 24 required)
Discussion: Horns can either be too loud, used too long, or too
often. In states where specific regulations on horn use have been
enacted, they preempt a community from any action except that on
unnecessary use. If you wish to develop a regulation limiting the
maximum sound level of horns, which we do not recommend at present,
then SAE Standard J377 might be used as a reference; In New York
City they have established a regulation (Ref. 3) which limits the
intensity of horn signals within the city limits. The numbers
chosen by them are 75 dB(A) at 25 feet. The City Council later
changed it to 106 dB(A). The City of Lakewood, Colorado (Ref. 4)
and the NIMLO Model Noise Ordinance (Ref. 1) have provisions similar
to the above but are considered to be excessively verbose, in that
much of the redundance in those provisions can be removed by proper
definitions of terms.
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7-55
Although not contemplated in the near future, standards
for the sound limits of vehicular horns may be placed on the
manufacturer by himself or the Federal government, in order to
avoid the disorder associated with a patchwork quilt of local regu-
lations. If the range of acceptable values specified in SAE
Standard J377 are used for choosing a limit similar to New York,
then unusually loud, modified horns will be proscribed.
6.2.2 Radios, Television Sets, Musical Instruments and
Similar Devices
(a) The operating or permitting the use or
operation of any radio receiving set, musical
instrument, television, phonograph, drum, or
other device for the production or reproduction
of sound, except as provided for in Section 6.2.3
in a quiet zone or
below,/ in such a manner as to cause noise disturbance, or
(b) The operating of any such device between the hours of
(X) p.m. and (Y) a.m. the following day in such a manner
as to be plainly audible across property boundaries or
through partitions common to two parties within a
building or plainly audible at fifty (50) feet from
such device when operated within a motor vehicle parked
on a public right-of-way or on a public space, or within
a watercrafty or on a common carrier by any passenger.
(Definitions 8, 15, 19, 21, 23, 24, 25, 40 required).
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7-56
Discussion: This section has some important differences from
similar ones that appear in other ordinances. The first part
reads "production or reproduction" to account both for devices
that make sound directly and those that are for the electrical
amplification of stored sounds. "Noise disturbance" (See
Section 3.2.19) is a newly defined quantity to restrict the
definition of disturbance to one that specifically relates to
noise and no other. During the night hours, it is more likely
that disturbance will occur; thus, latter parts of this section
quantify the disturbance further so the provision is more enforce-
able. In selecting X and Y, the following information may be of
use. Lakewood, Colo. (Ref. 4) uses 11 p.m. to 6 a.m.; Inglewood,
Calif. (Ref. 5) uses 10 p.m. to 7 a.m. Ref. 3 specifies no time,
which may create enforcement prlblems. San Diego (Ref. 2) uses
10 p.m. to 8 a.m.; Ref. 1 recommends 11 p.m. to 7 a.m. See step 10 of
Chapter i for a general discussion of night versus day limiting
and Article VIII discussion for time limits on stationary noise
hours .^Sinee noise from the sources of concern is highly sources.
fluctuating, it is difficult to measure, and the term "plainly
audible" is used (See Section 3.2.21). It represents the higher
annoyance associated with the clear understanding of a disturbing
parties' action and should be more enforceable than ordinary
"noise disturbance." This provision allows a phoned-in complaint
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7-57
to be analyzed through appropriate questions before any
action by the EPO is taken. Ref. 2 has included such a
provision but has not defined the term plainly audible.
Three common circumstances where this annoyance occurs
are specifically enumerated in the provision since each
must have a different distance criterion.
6.2.3 Exterior Loudspeakers
ALTERNATIVE 1
The operating, or permitting to be operated,
of any device in a fixed or movable position
exterior to any building or mounted upon any
motor vehicle or watercraft on any private
property, on any public right-of-way, or on
any public space, such that the sound therefrom
is plainly audible across the property boundary
of the source or on any public right-of-way or
in any public space, provided however, that this
section shall not apply to any public performance,
gathering, or parade conducted in accordance with
the provisions of a permit granted by the city
for such purposes.
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ALTERNATIVE 2
The operating, or permitting to be operated,
of any device in a fixed or movable position
exterior to any building or mounted upon any
motor vehicle or watercraft on any private
property, on any public right-of-way, or on
any public space, such that the sound therefrom
is plainly audible across the property boundary
of the source or on any public right-of-way or
in any public space in residential areas or
between the hours of (X) p.m. and (Y) a.m. the
following day.
(Definitions 8, 15, 21, 23, 24, 25, .40 required)
Discussion: The growth in the use of sound amplifying equipment
has expanded into the widespread use of exterior public address
systems in car lots, garages, racetracks, and other similar
places, and on personal motor vehicles (for some reason), and
on commercial and governmental vehicles for communication from
a central office to a driver who is not within his vehicle. As
is typical of P.A. systems, the gain is set so high that the
sound can be heard a long distance away in a residential community,
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7-5S
and it is an unnecessary noise intrusion in most cases.
The rapid spread of the problem is sufficiently new that
a provision to control it does not appear in ordinances.
A provision similar to the one above can be found in Ref. 1
for public rights-of-way. San Diego has adopted a provision
similar to that recommended in Ref. 1. See Step 10 of Chanter 2
for a general discussion of time limits to be applied to the
Alternative given above. This section does not limit the
applicability of Article VIII but is meant to supplement it
in cases where the noise is difficult to measure or the source
is on other than private property.
Certain types of noise control legislation may produce
some conflict with the constitutionally-protected rights of
freedom of speech and freedom of expression. These conflicts
have mainly been encountered in noise ordinance provisions
which restrict the use of sound trucks and loudspeakers,
particularly when permits for such use are required. They
are found when the standards are vague and subject to various
interpretations rather than when they have decibel limits or
other types of definitive measurements.
Problems that have been encountered in the constitutionality
of restrictions on sound truck or loudspeaker use are as follows:
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7-60
(1) The use of vague, ill-defined criteria for
prohibition or restrictions on the use of
these instruments.
(2) The requirement of a permit for use of these
instruments without definitive standards for
the grant of the permit, and
(3) The lack of a reasonable relationship between
the type of restriction and the objective to
be attained.
In areas within the limits of First Amendment freedom of
speech and expression protection, it is of the utmost importance
that any restrictions or prohibitions on the exercise of these
freedoms, such as on the use of sound trucks or loudspeakers,
be definite, explicit, and narrow in scope. Vague, undefined
restrictions may be found unconstitutional under the general
void-for-vagueness doctrine or under the First Amendment's
prohibition against the "chilling effect" a vague law may have
on the exercise of freedom of speech. However, when a provision
is clearly drawn with restrictions on use of exterior loudspeakers
to certain times, locations or sound levels, constitutional
problems are generally avoided. Thus, ordinances have been
upheld which limit the use of sound trucks to certain hours
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of the day, which prohibit use of sound trucks on certain
streets or in residential neighborhoods, or which limit the
sound pressure level of sound trucks or loudspeakers to
specific values (the latter, however, is difficult to achieve).
The requirement of an ordinance that a permit be obtained
from a city official before sound trucks or loudspeakers may
be used can also create constitutional difficulties. Such a
provision can be struck down as a "prior restraint" on freedom
of speech unless the ordinance contains clear, objective, non-
discriminating standards for determining whether and in what
cases a permit should be granted or denied. See Section 7.2
on page 100 in this regard. Without such standards the
ordinance is unconstitutional, as determined by the Supreme
Court in a 1948 case.
6.2.4 Street Sales
ALTERNATIVE 1
The selling of anything by outcry within any
area of the city zoned primarily for residential
uses, except by permit. The (insert proper agency
here) may issue permits for the sale by outcry
subject to such conditions, time limits, noise
standards and terms as it shall determine
appropriate to carry out the purposes of this
ordinance.
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ALTERNATIVE 2
The selling of anything by outcry within
any area of the city, zoned primarily for
residential uses, between the hours of
(X) p.m. and (Y) a.m. the following day.
(Definition 27 required)
Discussion: Although street sales by shouting are becoming
rare, this provision accounts for the event. Rather than
control the noise disturbance emanating from the outcry,
it is restrained by time and area limits. Permits may be
given for public events to avoid undue permit complexity
in cases where outcry is very likely, but noise disturbance
is likely to be small. The permit procedure should be con-
sistent with that used in granting other permits. See
Section 7.2 on page 100 for permit procedures.
6.2.5 Animals
The owning, keeping, possessing, or harboring
of any animal or animals which, by frequent
or habitual noisemaking, cause noise disturbance.
The provisions of this section shall < apply
to all private or public facilities, including
any animal pounds, which hold or treat animals, except
public zoos.
(Definition 19 required)
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Discussion: The use of "animals" is sufficiently broad so
that reference to birds, cats, and so forth is not necessary.
The provision relates to noise disturbance and not to a specific
numerical limit because animal noises are very transient and,
therefore, difficult to measure. The cause of a complaint may
be qone by the time an EPO or police officer arrives on the
scene to make a measurement anyway. The EPO may have great
difficulty in making a measurement of noise on a sound level
meter that would be usable in court if a dog barks only inter-
mittently. We cannot reconmend any simple measurement technique
that ties to a specific number to determine whether the ordinance
has been violated or not for such a dog. On the other hand, if
the dog barks frequently the provisions of Article VIII can be
used effectively. Thus, the provision is really a backup to
Article VIII for cases where animals make sounds infrequently.
See Refs. 12 and 13 for discussion of the barking dog problem.
Animal pounds and veterinary facilities, if poorly located,
can be a cause of severe community annoyance, and this section
includes them specifically. Since many public pounds are a
cause of community annoyance, they must also be included,
although some communities have exempted them in the past. By
including public facilities explicitly, the law gives a mandate
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for good planning when new facilities or improvements to
old ones are being considered.
Very large cities (Ref. 8, 14, 15) do not address noisy
animals, but smaller ones generally do. Sec. 9.52.080 of
Ref. 4 and Sec. 4608 of Ref. 5 are similar to the above pro-
vision. Many California communities have animal noise provisions
which are based on "annoyance to a reasonable person of normal
sensitivities," which we have here included in our definition
of "noise disturbance."
Suburban residential communities have a sub-
stantial number of noise complaints about barking dogs. In
Salt Lake City, for example, an average of 8-10 complaints per
da^ were received during 1973. In other communities, 60% of
the noise complaints may relate to barking dogs. We recommend
that for a noise control program to be effective, this section
of the ordinance should be enforced by the dog warden or a
similar official rather than the EP0. Lakewood, Colo, has a
special Office of Community Affairs, which is not related to the
Noise Control Office. They are responsible for answering general
nuisance complaints, one of which is dog barking. Salt Lake City
has an Animal Control Officer who is independent of the noise
program and handles all aspects of animal control including noise.
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6.2.6 Loading Operations
The loading, unloading, opening or otherwise
handling of boxes, crates, containers, garbage
cans, or otherwise similar objects between the
hours of (X) p.m. and (Y) a.m. the following day
or in such a manner as to cause noise disturbance.
(Definition 19 required) .
Discussion: This section applies to anyone creatinq such noise
whether commercial or private. It generally will rely completely
on complaints by a disturbed party. The noise disturbance part
applies at any time and is supplemented with a curfew during
nighttime hours when annoyance is greatest. See Step 10 on
page 35of Chapter 2 for discussions of time limits.
The transient noise from these sources may not allow
it to be easily measured on a sound level meter, so no numerical
standard has been applied here. This section does not preclude
the use of Article VIII in cases where measurement is feasible.
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6.2.7 Construction Noise
General Discussion: Construction noise is a severe
problem in the United States. It is caused by the
construction
high degree of/mechanization leading to intense noise,
and by the widespread application of those machines
leading to extensive noise both in time and space.
The noise, therefore, must be controlled. On the
other hand, the construction industry is politically
powerful and is doing an important job. They are wary
of additional regulations which may restrict their
profitability, so they take any proposed noise
regulations very seriously. If the provision con-
trolling construction noise is unreasonable (in their
view) their objections may be sufficient to prevent
the total noise ordinance from passing. The realities
of the situation dictate that the construction industry
be involved at the appropriate stage in developing the
ordinance (See Chapter2 ). There is little doubt that
construction noise needs to be controlled in larger
communities (See Ref. 17 and the introduction to Ref. 16).
The question here is how much. Some construction noise
can be highly transient and may be as difficult to measure
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as barking dogs or banging boxes.
The levels are so high, however, that serious
attempts are being made to find a technique to measure
construction sites. A simple technique readily usable
by an EPO, may be available soon. It is hoped that a
measurement standard by a professional society will be
developed. Section 6 of the Noise Control Act of 1972
(Ref. 18) requires the U.S. EPA to promulgate regulations
to control the noise emission levels of new construction
equipment. Reduced equipment noise will reduce site noise.
Preemption of new equipment noise standards by the Federal
government, however, will not prevent communities from
controlling site noise, nor from restricting the use or
operation of noisy equipment nor from requiring licensing
or certification of such equipment nor from restricting the
hours of use.
The alternative sections, proposed below, are a
temporary means available to communities, and suffer from
certain weaknesses, which is why they have been presented
after the general discussion. Specific comments on each
alternative will follow below.
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7-68
ALTERNATIVE 1
The operating, or causing to be operated, of
any equipment used in commercial construction, repair,
alteration or demolition work on buildings, structures,
streets, alleys, or appurtenances thereto, in residential
or commercial land use categories, with sound control
devices less effective than those provided on the original
equipment, or in violation of any regulation of the U.S.
Environmental Protection Agency; or between the hours of
(X) p.m. and (Y) a.m. the following day on weekdays and
between (X) p.m. Friday night and (Y) a.m. Monday morning
and on legal holidays (except by permit).
ALTERNATIVE 2
The operating, or causing to be operated, of any
equipment used in commercial construction, repair,
alteration or demolition work on buildings, structures,
streets, alleys, or appurtenances thereto which exceed
the sound level limits for an industrial land use as set
forth in Article VIII, except that the industrial land use
soundlevel limits shall apply for construction sites in
all land use categories.
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Discussion: Alternative 1 is a provision that restricts noise
during daylight hours to that emitted by original equipment or
that controlled by any regulations of the Environmental Protection
Agency and then applies a curfew during night hours. Alternative 2
ties construction site noise to maximum limits set for industrial
zones but allows that zone to exist in any land use category in
contradistinction to fixed noise sources such as factories. With
regard to times, Inglewood (Ref. 5) uses 10 p.m. to 7 a.m.; New
York (Ref. 3) uses 6 p.m. to 7 a.m.; Boston (Ref. 8) uses 7 p.m.
to 8 a.m.; Chicago (Ref. 15) has chosen 9:30 p.m. to 8 a.m. for
building construction; Lakewood (Ref. 4) uses 9 p.m. to 6 a.m.
NIMLO (Ref. 1) recommends 6 p.m. to 7 a.m., while San Diego (Ref.
2) uses 7 p.m. to 7 a.m. It appears that the general concensus is
to allow construction during normal working hours but to restrict
it during the evening (after 6 p.m.) and night (after 10 p.m.) hours.
In Alternative 1, the curfew is restricted in applicability to resi-
dential and conmercial land use categories. Alternative 2 applies
the level and time restrictions set forth for stationary noise
sources in Article VIII. The only difference here is that, since
construction can occur in any land use category, the industrial
noise limits are made applicable to all land use categories. One
may wish to include the original equipment, and U.S. EPA provisions
of Alternative 1 in Alternative 2.
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6.2.8 Vehicle Repairs or Testing
The repairing, rebuilding, modifying, or
testing of any motor vehicle (off road
vehicle) or watercraft on private property,
on a public righf-of-way or on a public
in a quiet zone or
space /in such a manner as to cause noise
disturbance and between the hours of (X)
p.m. and (Y) a.m. the following day.
(Definitions 15, 19, 24, 25, 40 required)
Discussion: With the proliferation in numbers of the wide
varieties of personal vehicles, much noise begins to be
associated with these vehicles at the residence of the
owners, as well as at repair shops. This provision pro-
vides both a nuisance and a curfew form of control, which
may be needed in addition to Article VIII, because much
of the activity produces transient sounds that are hard to
measure, such as hammering or speeding of engines. The
optional phrase in brackets must be included if the local
definition of motor vehicles does not include it.
6.2.9 Aircraft Operations
General Discussion: Many communities suffer serious noise
intrusions from aircraft overflights as well as from ground
operations. The seriousness of the complaints has resulted
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in a large number of suits, some of which have been
decided in high courts, and many have requested many
dollars in damages. As a result, the original regu-
latory controls of aircraft noise have been seriously
questioned both within and without the Federal government,
so it is difficult at the present time to predict how
much control a community will have over aircraft noise
intrusion. With regard to aircraft in flight, it appears
that no community can limit aircraft operational noise,
although it is far from certain. It is clear that com-
munities cannot exercise their police powers to regulate
aircraft noise. With regard to aircraft on the ground,
it may be possible for the airport proprietor to apply
controls, but even that is unclear. Ref. 50 should be
consulted for further details.
The running, testing, or otherwise operating of
or operating an airport facility
aircraft engines on the ground/in such a manner as to
cause noise disturbance or violate the provisions of
Article VIII. Nothing in this section shall be con-
strued to prohibit, restrict, penalize, or enjoin or
in any manner regulate the movement of aircraft which
are, in all respects, conducted in accordance with,
or pursuant to, applicable Federal laws, or regulations,
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or air traffic control instructions, or airport
proprietor regulations.
(Definition 19 required)
Discussion: The purpose of this provision is to control engine
runoff on the ground for maintenance or experimental purposes
and is a very limited control. Ref. 5 should be consulted,
particularly Part 8 which concerns aircraft noise. See Ref.
50 for a comprehensive discussion of aircraft noise. If your
community is already an airport proprietor, you should in-
vestigate the problem in some detail.
6.2.10 Places of Public Entertainment
ALTERNATIVE 1
The operating, or permitting to be
operated, of any loudspeaker or other source
of sound in any place of public entertainment
which produces maximum sound pressure levels
of (X) dB(A) at any point that is normally
occupied by a customer as read with the
slow response on a sound level meter, without
a conspicuous and legible sign located outside
such place, at the entrance, stating "WARNING!
SOUND LEVEIES WITHIN MAY CAUSE PERMANENT
HEARING IMPAIRMENT."
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ALTERNATIVE 2
The operating, or permitting to be operated,
of any loudspeaker or other source of sound in any
place of public entertainment that exceeds the levels
shown in Table B at any point that is normally occupied
by a human being.
TABLE B
Duration - hours per day Sound Pressure Level
dB(A) Slow Response
8 90
6 92
4 95
3 97
2 100
1 1/2 102
1 105
1/2 110
1/4 or less 115
ALTERNATIVE 3
The operating, or permitting to be operated, of any
loudspeaker or other source of sound in any place of public
entertainment without the use of a compression amplifier
or other device to automatically limit the maximum sound
emitted by any device to (X) dB(A) at any point that is
normally occupied by a human being.
(Definitions 1, 30 required)
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Discussion: The level of music heard arid accepted by
young people has increased significantly in recent
years. The chances that it will decrease naturally in
the future appear to be small because of the increased
dependence on fancy electrical amplifiers by music groups.
The levels are high enough now to raise grave questions
about the continued good hearing of the listeners. The
musicians themselves are experiencing far higher levels
and longer durations of noise exposure than the listeners,
and there is little doubt about the effect on their hearing.
The environmental noise, through buildings, walls, and
closed doors and across property lines, has caused violations
of land use limits such as those discussed in Article VIII
(See Ref. 19). The excessive exposure is found not only in
so-called "beer joints," but also at high school dances and
in homes. In some unpublished work by the authors, it was
found that the L5Q was 103 dB(A) at a junior high school
dance when averaged over two hours. The figure attached
relates very closely to these numbers, and the temporary
hearing loss caused by such noise is evident.
The three alternatives presented here are considered to
be enforceable. Alternative 1, like the others, is intended
to protect the musician as well as the listener. It is worded
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2S0
500
1000 2000
HERTZ (HZ)
4000
8000
Figure 6.2.10 Hearins levels measured at various times after a 2-hour
exposure to a broad-band noise at 103 dBA as compared
with pre-exposure determinations. (Sln^le^ subject data
taken from the Public Health Service laboratory in
Cincinnati, Ohio).
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so that even if the musician wears ear plugs or ear muffs,
the provisions apply. It is aimed primarily at public
education, and the only requirement is that of a sign.
It does not interfere with the right of people to deafen
themselves and is modeled along the lines of the U.S.
Surgeon General's warning on cigarette smoking.
Alternative 2 is more regulatory and specifically
lists the exposure levels adopted under the U.S. Occu-
pational Safety and Health Act (OSHA), which may already
be applicable to the employees of the performing group.
Enforcement of this alternative would be more difficult,
but may be more fair to the performers whose music has a
wide variety of sound levels associated with it. The
constitutionality of this provision may be in question
and, hopefully, in the future test case litigation may
resolve that question.
Alternative 3 makes use of technology and requires the
use of an automatic level-limiting device in places of
public entertainment. It raises the initial cost of a
sound system but affords the user protection from over-
zealous enforcement: he can have confidence that once
set correctly, his system will not get him into trouble.
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Instead of responding to complaints, the EPO will be
required to approve installations as they are used.
Thus, more effort may be required but more protection
will be afforded; for young school children this may
be critical.
With regard to the levels to be chosen, Lakewood
(Ref. 4) Isas used Alternative 2. NIMLO (Ref. 1) recom-
mends 95 dB(A) sustained for more than thirty (30)
seconds. It also uses the word "enclosed," which is
considered unnecessarily restrictive, because there
are many open or partially enclosed places where this
problem occurs. Although our list of references is not
exhaustive, it is not likely that many communities have
attacked this very important problem which is not, in
the pure sense, an environmental noise problem. For
choice of a number in Alternatives 1 and 3, you may
consider typical exposure times and then consult the
chart in Alternative 2. As supplementary data, you
may wish to consult the attached figure which shows
the hearing of a subject after a 2-hour exposure to
broadband noise at 103 dB(A). It took 24 hours for
that person to nearly recover his normal hearing.
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Section 2 of Chapter 4 discusses hearing loss more fully,
and there are U.S. EPA documents which may be helpful on
this subject. (Ref. 6, 20).
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6.2.11 Impulsive Sources
ALTERNATIVE 1
The using of fireworks, explosives, or the
firing of guns or other explosive devices so as to hp
audible across a property boundary or on a public space or
right-of-way without first obtaining a permit.
ALTERNATIVE 2
The using of fireworks, explosives, or the
firing of guns or other explosive devices between the
hours of (X) p.m. and (Y) a.m.
(Def. 1, 10, 18 required).
Discussion: There are many sources of impulsive noise in
the daily activities of a community. The more intense ones
are listed in the provision above, although there are others
such as a motorcycle backfire, and it is these that generally
create annoyance. Although it is possible to measure impulsive
noise properly with a good quality sound level meter, it is not
encountered sufficiently often to warrant the extra cost in
smaller communities. The definition of impulsive noise has
been modified from the scientific one so that a value of (x)
dB(A) can be chosen (See Section 3.2.10). The permit is to
allow authorized construction noise, such as hammering nails.
Ref. 20 gives a good discussion of the effects of impulsive
noise on humans. The second alternative is also easy to
enforce, and you may wish to combine both alternatives.
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If you purchase an impulse sound level meter, it may
be desirable to obtain one that will hold the peak
level, especially for single events, such as explosions.
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6.2.12 Motor Vehicle Racing Events.
ALTERNATIVE 1
Operating or permitting the operation of any
motor vehicle racing event at any place between
the hours of (X) p.m. and (Y) a.m. the following
morning.
ALTERNATIVE 2
Operating or permitting the operation of
any motor vehicle racing events at any place
except an authorized track and in a manner
Environmental Protection Offi
approved by the (City Manager)/or his desi-
gnated representative to minimize noise
disturbance.
(Def. 14, 18 required)
Discussion: Motor vehicle races are becoming a big professional
and recreational sport. Dirt motorcycles, go-carts, stock cars
all are raced; drivers demand maximum performance and do not
use mufflers at all. Some recent measurements made by EPA at
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some stock car tracks have shown that a single car by
itself can create sound levels as high as 128 dB (A)
at the driver position, up to 117 dB(A) in the front
row of the spectator stands, and up to 60-70 dB(A)
1.5 miles into the community. How to control this
severe source of noise is a problem. Vehicles licensed
for street use will already be controlled by Article IX.
It may be possible to apply district boundary limits of
Article VIII, but racing events are more infrequent and
should have special allowance. This allowance could be
given by controlling the noise directly from the vehicles,
and this is the best approach. Since it is not clear
what standards should be set, Alternative 2 allows
for a permit and/or approval on the operation of the event
to minimum annoyance. Alternative 1 presumes that a night
curfew is desirable and the times to set would be the night
hours, as discussed in other parts of this chapter and in
Chapter 2.
6.2.13 Powered Model Vehicles.
Operating or permitting the operation of
powered model vehicles between the hours
of (X) p.m. and (Y) a.m. the following
morning. Maximum sound levels
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during the permitted period of operation
shall conform to those set forth in Table
1 of Section 8.1 of Article VIII and shall
be measured at the property boundary of the
source or at a distance of (x) feet, if it
is operated in a public place.
(Def. 22, 23, 30 required)
Discussion: Small, unmanned mechanical devices used primarily
for recreational purposes, now are very widespread. Model air-
planes, boats, and cars are examples. This provision has been
adapted from San Diego (Ref. 2) and San Francisco (Ref. 14).
San Diego has set 9 p.m. and 7 a.m. as the time limits and from
40 dB(A) to 75 dB(A) as the level limits depending on land use,
and at 100 ft. San Francisco, on the other hand, allows use at
anytime as long as the maximum level does not exceed that per-
mitted in a table specific for these vehicles, which caries from
50 dB(A) to 75 dB(A). In public spaces, 85 dB(A), or less is
required at 50 ft.
The purpose of Article VIII is to control continuous sources
of noise with some allowance for durations shorter than one hour.
It is reconmended that those values be used for powered model
vehicles. It will simplify the provision and achieve the
objectives of Article VIII.
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6.2.14 Dynamic Braking Devices
ALTERNATIVE 1
Operating any motor vehicle with a dynamic braking
device engaged which does not meet the requirements of
Article IX.
ALTERNATIVE 2
Operating any motor vehicle of ten thousand pounds
gross vehicle weight or greater with a dynamic braking
device engaged except for the aversion of imminent danger.
(Def. 7, 14 required)
Discussion: Dynamic brakes, a common version of which is
called a Jacob's brake after the manufacturer, can be life-
savers on steep highways. Alternative 1 is the best solution
in that it requires the vehicle with a dynamic brake to be as
quiet as one without. A somewhat better muffler may be required
on the vehicle. Since trucks engaged in interstate commerce
will be regulated by the Federal government, Article IX should
reflect that preemption; and this section would merely extend it
to dynamic brakes which may or may not be covered in the Federal
regulations.
Alternative 2 is merely a prohibition of their use. It
could be changed to a curfew, which is not recommended because
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many heavy trucks are passing through and would be more
aware of a prohibition than the hours of a curfew. This
alternative should be chosen, only if Federal preemption
removes your power to regulate the vehicle operation.
Lakewood (Ref. 4) has a provision similar to
Alternative 1 but fails to define "proper muffling."
6.2.15 Refuse Compacting Vehicles
ALTERNATIVE 1
The operating or permitting to be operated, any
motor vehicle which can compact refuse and which creates,
during the compacting cycle, a sound pressure level in
excess of (x) dB(A) when measured at (y) feet from any
point of the vehicle.
ALTERNATIVE 2
The operating or permitting to be operated, of any
motor vehicle which can compact refuse, between the
hours of (X) p.m. and ( Y) a.m. the following day (in
residential use districts).
(Def. 1, 14, 30 required)
Discussion: Alternative 1 puts a noise limit on the vehicles,
and Alternative 2 puts a time limit on their operation and
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possibly the area of curfew. You may wish to consider
both alternatives together if the problem is severe
enough, just as was mentioned previously on powered
model vehicles. Salt Lake City, Utah (Ref. 41) reports
they are able to obtain refuse compacting vehicles which
average a low 60-65 dB(A) at 50 feet. The noise is due
to high engine RPM to drive a high speed pump, and recent
modifications use a low speed pump and require no engine
speedup, so drastic noise reductions have been obtained
at modest prices. San Diego (Ref. 2) requires 86 dB(A)
at 50 feet, and in 4 years will require a reduction to
80 dB(A); both are too high in light of the Salt Lake City
experience. San Diego also prohibits collection in resi-
dential areas from 7 p.m. to 7 a.m. Lakewood (Ref. 4)
prohibits collection in residential districts and within
300 feet of hotels or motels from 10 p.m. to 7 a.m. San
Francisco (Ref. 14) has an extensive section, but basically
requires 80 dB(A) at 50 feet now and 75 dB(A) in 5 years,
both already have been met by existing vehicles. New York
City (Ref. 3) requires 70 dB(A) at 10 feet by December 31,
1974 (nearly 57 dB(A) at 50 feet). Although this require-
ment appears unnecessarily restrictive at present, it will
certainly stimulate industry interest in quieting, considering
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the amount of garbage one finds in New York.
These vehicles are usually standing on a public
right-of-way so they do not fall under Article IX and
must be covered by the separate provision suggested here.
6.2.16 Standing Motor Vehicles.
Operating or permitting the operation of
the motor of any motor vehicle whose
manufacturer's gross weight is in excess
of ten thousand (10,000) pounds, or any
attached auxiliary equipment for a period
longer than (x) minutes in any hour while
stationary
such vehicle is on a public right-
of-way in residential district or in any
designated quiet zone, or is on private
property in a residential or commercial zone
and is not within a completely enclosed
structure.
(Def. 14, 24 required)
Discussion: This provision is aimed primarily at large diesel
trucks that idle while loading or unloading. Diesel trucks are
generally louder and operators wish to idle them to prevent the
adverse effects to the engine associated with start-stop cycling.
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Since the vehicle will have a manufacturer's noise limit
regulated by EPA and an operational limit due to Article IX,
the only feasible approach to control this source of noise
is a prohibition of long-term idling in areas that can effect
people that are most noise sensitive.
Chicago (Ref. 15) has chosen two minutes, Lakewood
(Ref. 4) uses five minutes, and New York City uses three minutes.
6.2.17 Vibration.
Using or causing the use of any device that
creates vibration which is above the perception
or beyond
threshold of any individual 'at/the property
boundary of the source on private property or
at (x) feet from the source if on a public space or
right-of-way.
(Def. 6, 19, 23, 35 required)
Discussion: Vibration can be a severe problem in many locations
due to sources such as triphammers, stamping machines, railroad
locomotives, and elevated expressways. Vibration in the context
used here is the mechanical motion of solid materials (as opposed
to liquid or gaseous materials). Vibration of solids almost always
results in sound (vibration of the air), but generally vibration
annoyance is at low frequencies where people can feel it more than
they can hear the sound made by it. Thus, it is practical to
separate vibration from sound for regulatory purposes. Aside
from feeling the effects, objects can vibrate to cause annoyance.
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Sources on public property must be measured at some distance.
Unfortunately, there is no regulation which can be cited that
gives a distance at the present time. Note that this section
establishes numerical limits, since the definition of "perception
threshold" refers to a standard which gives limits of allowable
vertical acceleration for the band of frequencies to which humans
are most sensitive. Application of this standard would require
the use of special measuring equipment not normally available to
an EPO. Generally, the reduction of vibration of heavy equipment
would be expensive and regulation would not be readily accepted
by the responsible party without documentation.
Vibration sources are often tied closely with sources of
impulsive noise and infrasound. Impulsive noise is covered in
Section 6.2.11 and infrasound has not yet been shown to be a
severe environmental noise problem so no recommendations have
been made to control it.(See Ref. 20 for a discussion of infra-
sound).
Chicago (Ref. 15) has a general prohibition against earth-
shaking vibration and attempts to define the perception threshold
by stating "perceptible without the aid of instruments." The
recommendation here ties that perception to specific numbers.
Lakewood (Ref. 4) has also adopted a provision similar to Chicago.
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6.2.18 Bells and Alarms.
ALTERNATIVE 1.
(a) The sounding, or permitting the sounding of,
for wore than (x) minutes in any hourly period in
the open air, of any electronically amplified signal
from any bell or chime or other device from any clock,
school, house of religious worship, or governmental
or (b) the
buildings;/sounding or permitting the sounding of any
exterior burglar alarm on any building or motor vehicle
unless such burglar alarm shall terminate its operation
within (y) minutes of its being activated. Any motor
vehicle upon which a burglar alarm has been installed
shall prominently display the telephone number at which
communication may be made with the owner of such motor
vehicle.
ALTERNATIVE 2.
(a) The sounding, or permitting the sounding of, any
(electronically amplified)signal from any bell or chime,
or other device, from any clock, school, house of religious
worship, or governmental building in the open air between
the hours of ()() p.m. and (%) a.m. the following day. Sound-
ing or permitting the sounding of any exterior burglar alarm
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on any building or motor vehicle unless such
burglar alarm shall terminate its operation
within (y) minutes of its being activated. Any
motor vehicle upon which a burglar alarm has been
installed shall prominently display the telephone
number at which communication may be made with the
owner of such motor vehicle.
ALTERNATIVE 3
The sounding or permitting the sounding of,
any (electronically amplified) signal from any
bell or chime, alarm, or other device, from any
clock, school, house of religious worship, building
or motor vehicle in the open air.
(Def. 14 required)
Discussion: The use of bells, chimes, or alarms has not
changed their purpose significantly in the recent past.
However, people are becoming slightly less tolerant of them.
The major change is in the development of electronic
amplification. Where once a bell could be heard at a
locally,
reasonable level/ it can now be amplified to be heard
throughout a small community and thus cause a severe
noise problem for those living near the source. The
three alternatives given above are all
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7-9n
intended to control electronically amplified sources of sound
and so in no way restrict the ringing of natural bells or chimes.
If your community wishes to control natural bells and chimes, the
appropriate phrase in the alternatives can be deleted. The basic
differences between the alternatives is that the first restricts
the use during any hour so is similar in enforcement to that
for Article VIII, while the second places a curfew during night
and the third prohibits their use entirely,
hours / The alternatives can be combined also to make two restrictions.
No recommendation on the upper limit to sound level is given because
of the lack of detailed knowledge available, although the implied
intent of this recommendation is that it be no lower than the natural
version of the source. Note that government buildings are also in-
cluded since they often are a source of annoyance.
With regard to burglar alarms, only a time limit is recommended
since the intent of an alarm is to create alarm. Motor vehicle alarms
are becoming quite popular in urban areas and are a source of severe
annoyance if unusually prolonged.
Lakewood (Ref. 4) prohibits bells from 10 pm to 7 am, but does
not address alarms specifically although it may be possible to
construe their Subchapter IV, Amplified Sound, to cover alarms.
Inglewood (Ref. 5), as well as several other communities, could use
their registration powers to control excessive bell or loudspeaker
noise^ (Ref. 5, Section 4614). Their ordinance may conflict with
itself in that case since Section 4618(d) states "... sound
amplifying equipment shall not be operated within 200 feet of
churches, schools ..." Church bells particularly can be an
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emotional issue and it is recommended that the ordinance
be clear on its control. San Diego (Sec. 59.5.0701)
specifically exempts bells and chimes as long as they
do not "cause a noise disturbance." New York exempts
them completely.
San Diego (Ref. 2, Sec. 59.5.0503) has a specific
section on motor vehicle burglar alarms and allows
activation for 15 minutes only. The police are per-
mitted to deactivate the alarms if necessary, suggesting
the severity of the annoyance problem. New York City
(Ref. 3) also has this provision. Boston (Ref. 8)
allows for 30 minutes and requires registration.
6.2.19 Fixed Sirens, Whistles, and Horns.
ALTERNATIVE 1
(a) The sounding or causing the sounding of any
whistle or horn attached to any fixed device (at
any time (or "between the hours of (X) p.m. and (if)
a.m.) except as a sound signal of imminent danger.
ALTERNATIVE 2
(a) The sounding or causing the sounding of, any
whistle or horn attached to any fixed device, which
creates a sound pressure level in excess of (x)
dB(A) at any point (y) feet distant from the source.
(b) The testing of any fixed emergency signal device
except at ( or more often than once every
(Def. 1, 6 required)
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Discussion: Alternative 1 does not regulate levels
specifically but does provide a time limit on whistle
operation. Alternative 2 puts an upper limit on the
level allowed, as well as restrict the period of testing
or operation. The testing of air raid sirens and starting
work at the sound of a factory whistle is rapidly disappearing,
can be
but/ a source of community annoyance if used today. There
are methods by which a siren may be tested without significant
acoustical output and many volunteer fire departments on the
east coast are using home beeper systems for an alarm call
rather than wake the entire community to crowd around the
fire site.
Both New York (Ref. 3) and San Diego (Ref. 2) give
exception for starting and stopping work, as well as for
imminent danger. Salt Lake City (Ref. 21) and Chicago (Ref. 15)
prohibit start-stop signals, which we also recommend.
San Diego (Ref. 2) and Inglewood (Ref. 5) have sections that
specifically mention train whistles. San Diego restricts
their level to 89 dB(A) at 300 feet, while Inglewood has
90 dB(A) at 300 feet. That level is required only
between 10 p.m. and 7 a.m. There may be a Federal ore-
emption conflict in attemotinn to reaulate any aspect of
6.2.20 Watercraft railroad activity.
Operating, or causing the operation of,
any motorboat in any lake, river, stream,
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7-92a
or other waterway in such a manner
as to violate the provisions of
Article VIII.
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ALTERNATIVE 2.
See Section 9.2 of Article IX for
provision.
(Def. 15 required)
Discussion: Pleasure boats, particularly in suburban
residential lake areas can cause a severe amount of
annoyance to residents around the lake. Hot-rodding
and water skiing are favorite pastimes. Boating of
this sort is fundamentally different than motor vehicles
on a public right-of-way in that the boat, which most
likely will make many passbys during a given period,
will be clearly identifiable to an annoyed recipient
and will cause a more sustained noise intrusion.
Alternative 1 makes the boat
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comply with the provisions for stationary noise sources.
This allows a boat passing by only once complete freedom,
but restrains one that is making continual passes.
Alternative 2 puts an operational limit on motorboats and
is discussed more fully in Article IX. Alternative 1 can
be handled on shore by an EPO, while Alternative 2 would
generally require a boat.
6.2.21 Quiet Zone_s
Creating any unnecessary or unusually loud sound within
the vicinity of any school orj other institution of learning,
hospital, nursing home, court, or other designated area
where exceptional quiet is necessary, while the same are
in use, provided conspicuous signs are displaced in
adjacent or contiguous streets, indicating that the same
is a quiet zone.
Piscussion; There are many noise sensitive activities in a
been
community that have/inadvertently placed in noisy areas by
community growth. Typical of this is the neighboring hospital
whose bordering streets have seen rapidly increasing volumes
of traffic to accommodate the growing number of employees and
patients. Good land use planning prevents such problems for
the future and zone downgrading can make the neighborhood
compatible in the future, but traffic noise will not be directly
solvable.
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This provision is intended to warn persons nearby that
care should be taken to avoid unnecessary noise and the
primary result is the requirement for conspicuous signs
to be placed around the area. Another even more effective
means of controlling noise impact on people in structures
of this type is through the use of an exterior wall sound
transmission loss requirement in the building code (See
Article X).
Refs. 2, 3, and 4 plus others have a provision
similar to that given above, and all are probably based
on the NIMLO recommendation (Ref. 1).
6.2.22 Domestic Power Equipment
(a) Operating, or permitting to be
operated, any powered saw, sander,
drill, grinder, garden equipment or
tools of like nature, used primarily
for domestic purposes, outdoors in
residential zones between the hours of
(X) p.m. and (W) a.m. the following day or;
(b) operating, or permitting to be
operated, any such power equipment in
such a manner as to violate the pro-
visions of Article VIII.
(Def. 1, 30 required).
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7-9*
Discussion: There are many forms of machinery used in
residential areas, such as chain saws and lawnmowers, that
can be a source of conmunity annoyance. Article VIII which
relates to residential zone noise problems cannot always
handle these sources which are typically moving and variable
in their sound output, and are on for
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only a short period during the day. Thus, it becomes
an enforcement problem for an EPO to use the district
levels in that article which is primarily intended for
continuous and reasonably steady sources of sound,
although it can be applied when possible as a backup.
This provision also contains a curfew and should not
be subject to Federal preemption related to the sale
of new products.
Chicago (Ref. 15) has set maximum level limits of
70 dB(A) at 50 feet for small powered equipment in 1975,
but it is a prohibition of sale provision that may be
preempted. Salt Lake City (Ref. 21) has copied Chicago's
provision. Lakewood (Ref. 4) uses 7 a.m. and 10 p.m. as
the time limits, 5 horsepower, and 80 dB(A) at 25 feet
(74 dB(A) at 50 feet). Boston (Ref. 8) will restrict
domestic powered equipment to 70 dB(A) at 50 feet in 1975,
going to 65 dB(A) in 1978.
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ARTICLE VII EXCEPTIONS AND PERMITS
Section 7.1 Emergency Exception
Noise caused in the perforit&nce of emergency work for the
immediate safety, health, or welfare of the community or
individuals of the community, or to restore property to a
safe condition following a public calamity shall not be
subject to the provisions of this ordinance. Nothing in
this section , however, shall be construed to permit law enforcement,
ambulance, fire, or other emergency personnel to make
excessive noise in the performance of their duties when
such noise is clearly unnecessary.
Discussion: Noise surveys (Refs. 12, 13) in smaller
communities indicate there is a high degree of annoyance
associated with emergency sirens, even though sirens are
necessary for a number of reasons. Sirens denote danger
and raise the tension level in those who hear them. In a
quiet community, almost everyone might hear a siren when
only a few need to respond to it. This situation probably
gives rise to annoyance. The second part of the above
section is intended to instruct governmental
personnel to reduce unnecessary noise. This caution is not
the only one recommended , since there are many noisy
governmental operations beside emergency ones. It is
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recommended that controls on siren noise be instituted
and Articles IV and V require that this be done.
In Boulder, Colorado,coordination of the EPO, the fire,
police, and private ambulance services have resulted in a
policy where sirens are used continuously only on certain
classes of calls and are used only at major intersections
in other classes. Salt Lake City has thoroughly indoctrinated
their officers on restricted siren use and they are monitored
continually; they report no degradation of their effectiveness.
The advent of the "quiet" car (which is well sound insulated)
and the increasing use of earphones in vehicles makes the reliance
on sirens more and more questionable.
Most communities give themselves blanket exemption from
many of their laws, but in the interest of credibility, this
should not necessarily be so. Baltimore (REf. 22) specifically exempts
emergency vehicles. New York (Ref. 3) has a provision more
like that recommended above, and the last phrase pertaining
to sirens is "... shall not be operated ... for a period of
time longer than is strictly necessary to respond to such
emergency." With the number of emergencies in,and population
density of;New York, they should be keenly aware of this problem.
Salt Lake City (Ref. 21) specifically exempts emergency pressure
relief valves as well as other safety signals. Lakewood (Ref. 4)
specifically prohibits use of fire alarms when returning from a fire.
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Section 7.2 Permit Issuance
The EPO is authorized to grant permits
for exception from any provision of this ordinance,
subject to limitations as to area,
noise levels, time limits, and other terms
and conditions as it determines are appropriate
to protect public health, safety, and welfare
from the noise emanating therefrom. This
Section shall in no way affect the duty to
obtain any other permit or license required
by law for such activities.
Discussion: This provision requires permits in cases where
they might otherwise not be needed if noise were not a con-
sideration. It gives the EPO authority to limit such events,
as public parades, so as to protect the health and welfare.
It is similar to that recommended by NIMLO (Ref. 1), and the
exact phasing is subject to the local method of granting
permits. The first consideration is the desirability of
granting permits on a case-by-case basis. A community
may desire to grant a blanket exception to certain social
activities, such as church bells, sports events, or parades;
this should be explicitly given in the ordinance in Article VII.
There will always be some other justified activity for which a
permit or variance will be necessary. The complexity of the
permit procedure will depend primarily on the severity and
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extent of the activity. In many cases, communities
felt obligated to spell out in great detail both the
permit procedure and the appeals procedure for un-
favorable decisions. Section 6.2.3 of this ordinance
should be particularly examined in this regard.
San Diego (Ref. 2) and Baltimore (Ref. 7) give
the Administrator the power to grant permits or variances
without great detail on the methodology to be used.
Section 7.3 Exemptions for Time to Comply
(a) Upon good cause shown by the owner
of any sound source, the (City Administrator)
shall have the power to grant an exemption
from the provisionsof this ordinance in order
to allow time for installation of
control equipment, facilities, or
modifications to achieve compliance not to
exceed (x) days, provided that such exemption
may be renewed for an additional like period,
but only if satisfactory progress toward
compliance is shown.
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(b) Any person seeking an exemption for time
to comply
shall file a petition with the (En-
vironmental Protection Officer). The
(Environmental Protection Officer) shall
promptly give written notice of such
petition to any person who has in
writing requested notice of such
exemption petitions, and shall publish
notice of such petition in a newspaper
of general circulation within this munici-
If
pality. / the (Environmental Control Officer},
in his discretion, concludes that a hearing
would be advisable, or if any person files
a written request for a hearing or a written
objection to the granting Qf such exemption
within (y) days of the notice provided herein,
a hearing shall be held on the petition. A
written transcript shall be kept of any such
hearings.
(c) In granting or denying an exemption,
the (Environmental Control Officer) shall
file and publish a written order, stating
the facts and reasons leading to his decision.
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Discussion: This section provides a means whereby a
person in violation of the ordinance may be secure from
prosecution temporarily. A permit is permission to
perform an activity,while a variance or exemption is
permission to violate the law. Of necessity it must
be of a temporary nature so it is mandatory to include
a time limit of (x) days, otherwise every potential
violator will request an exemption.
NIMLO (Ref. 1) has recommended, and Lakewood (Ref. 4)
and Salt Lake City (Ref. 2) have adopted, an undue hardship
provision which is, in essence, the above-recommended pro-
vision without a definite time of operation. If a community
desires to give a blanket exception to some activity, then
it should be specifically called out in the ordinance, in
order to minimize the use of the variance or exemption
procedure. Ref. 9 has a more complex procedure outlined
in the model state noise legislation.
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ARTICLE VIII. SOUND LEVELS BY RECEIVING LAND USE
Section 8.1 Maximum Permissible Sound Levels.
It shall be unlawful for any person to operate,
or permit to be operated, any stationary source
of sound in such a manner as to create a sound
level which exceeds the limits set forth for the
receiving land use CLand Use Category) in Table 1
[Jas set in zoning ordinance] below more than ninety
percent of any measurement period, which shall not
be less than (x) minutes when measured at the
prpperty boundary or at any point within the
property affected by the noise. When a noise
source can be identified and its noise measured
in more than one land use category, the limits of
the most restrictive use shall apply at the
boundaries between different land use categories.
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1.
Receiving Sound Pressure Level
Land Use Category Time Limit.dB(A)
R-l, R-2, etc. (A) a.m. - (B) p.m.
(or Residential, (B) p.m. - (A) a.m. and ^
Institutional)
C-l, C-2, etc. (C) a.m. - (D) p.m. N3
(or Commercial) (D) p.m. - (C) a.m. and
M-l, M-2, etc. (E) a.m. - (F) p.m. Ng
(F) p.m. - (E) a.m. and
(or Industrial) Nr
(Def. 1, 2, 3, 13, 20, 23, 30, 33 required)
Discussion: This section, along with Section 9.1 on vehicular
noise, will be the backbone of any noise control program and
needs full discussion, both with regard to its concepts
and its enforcement.
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THE PROBLEM
Increasing population density, wherever it occurs, brings in-
creasing acoustical interaction between people. The noise intrusions
(from the regulation viewpoint)
associated with these interactions can be conveniently/subdivided into
intrusions that occur only once, such as a motor vehicle passing by,
and intrusions that occur continually.
The single intrusion must be enforced by
an individual charged with identifying and measuring noise offenders;
the recipient seldom can identify the source himself; With continuous
intrusions, the noise source most often can be identified by the
recipient,so it is possible to enforce an ordinance on a complaint
basis. The continuousintrusion problem is primarily due to stationary
sources emitting noise across property boundaries and
is addressed by Article VIII of the ordinance. The single event
intrusions are caused mostly by motor vehicles and are the subject
of Article IX following.
The total noise received by any individual is the sum of all
sources, some continuousand some single event. Complaints about
continuoiisnoise intrusions are based on two factors: the acute
noise intrusion or the highest level maintained, and the chronic
noise intrusion, the levels experienced most of the time. This
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7-lQ5b
section of the article addresses the chronic noise
intrusions and later sections address the acute in-
trusions. It is important to note that we are con-
cerned with only exterior to exterior noise intrusions,
so the definition of property boundary (Section 3.2.23)
has been written to exclude interior to interior in-
trusions, such as noises across party walls, which are
more properly included in Article X.
The noise intrusions with which we are concerned
here have several significant factors that must be
identified and incorporated into the provisions to
make a workable ordinance. These factors are:
A. Method of Enforcement. How an ordinance is
to be enforced is as important a consideration
are
a^ the acoustical aspects.
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7-106
B. Location. People can accept more noise at
certain places than at others, and certain
activities are inherently more noisy than
others. Measurement location is also important.
C. Time of Day. People's activities at various
times of day will play an important role in
their degree of annoyance.
D. Frequency. The frequency distributions of the
noise must be allowed for to account for the
range of human hearing and the annoyance factor
associated with it.
E. Level. The amplitude or loudness of the noise
must be controlled ,so a specific number must be
chosen as an upper limit.
F. Duration. The period of time that people are
subjected to the noise is important.
G. Steadiness of Level. Whether the sound is steady,
fluctuating, or intermittent, continuous or
interrupted plays a role in annoyance. (See
Section 3.7 of Chapter 3).
H. Source Identification. If the source of noise
is identifiable both visually and with the ear,
it is more likely that there will be a growth in
annoyance with time. Background or ambient noise
has important bearing on identification also.
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THE SOLUTION
The discussion below is concerned with writing regulations
on stationary noise sources. Each Subsection below addresses the
specific problem areas outlined above and in the same order.
A. Method of Enforcement. Enforcement schemes can be sub-
divided into two .categories: The social aspects and the
technical aspects. The social aspect pertains to whether
the enforcement program is to be active, i.e., have officials
who go into the field and find violators, or passive, i.e.,
have officials who only make measurements in response to
of '
complaints. All programs ^hich we are aware have personnel
who respond primarily to complaints. This may be by default,
since in large cities there are more than enough problems to
keep an EPO busy, and in a small city the EPO may wear several
hats so he is still busy. Alternatively, one can say that
noise is not of enough importance to community officials to
warrant taking an active role in controlling stationary noise
sources. The social aspect of enforcement does not play a
large role in determining how an ordinance provision is to be
written. The technical aspects to be used for enforcement
can be divided into three basic schemes.
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7-106b
The first scheme is the maximum level method. The
limits set forth in the ordinance are interpreted to mean
that the noise level caused by the source in question can
never exceed that limit under any conditions of operation.
This enforcement scheme is used by the City of Chicago.
The method has certain important advantages: the ordinance
can be written simply and the enforcement process is simpler
for the EPO. He need only wait until some instant when the
sound level is in excess of the limits and he has secured
a violation. For many industrial sites with loading or
stamping operations he need not be at the property boundary
very long. Thus, an EPO could cite a number of noise
violators in one day. In court he need only establish that
the level, in fact, exceeded that in the ordinance and the
issue is over, at least insofar as he is concerned. The
fact that this sound occurred only once during the day and
then only for a few seconds does not get recognitionj thus
the added complexity of accounting for time duration is
to
eliminated. The method applies only/the loudest noises,
usually
and these are /the ones to be reduced first. In severely
noise impacted areas, this method will keep an EPO suf-
ficiently busy to justify the program and this is a workable
numerical level
and simple method, provided the / chosen for the ordinance
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7-106c
is reasonable. Any EPO with sense will use his judgment
in determining which of the loud sounds from the site in
question are to be considered as a violation. He may dis-
regard the noise from the accidental impact of a truck against
a garbage can for example; thus, he really disregards the more
extreme and infrequent noise intrusions subjectively.
The method has certain potential disadvantages. It
needs the strong backing of the courts which may not be forthcom-
ing if an alleged violator can make a case that prohibiting a
once-a-day noise which is over the limit for only a few
seconds, is an unreasonable infringement on his activities
and that the noise does not significantly effect public
health and welfare. More importantly, advance warning of the
intent to enforce the law in this manner can, in many cases,
insure that the ordinance will never be passed in the first
place. Most important, however, is the fact that only the
acute noise intrusions from the site are considered. If the
limits are set very low, then the chronic noise intrusions,
which are less than the maximum, are no problem. Other
problems occur if the enforcement methodology requires noise
levels to be exceeded for a portion of a time period for a
violation to occur (e.g., the Federal Highway Administration
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7-106d
sets 70 dB(A) as a limit to be exceeded only 10% of the
time). You may be able to
stand 70 dB for 10% of the time, but this method of en-
forcement might allow 70 dB 100% of the time! In con-
clusion, the maximum level method is excellent for
large communities, the enforcement problems are less
complicated than for other methods, but it does not
address the total noise environment and may require
exceptional support from the public in order to get the
ordinance enacted.
The second scheme may be called the cumulative
distribution method and is the one recommended here. Sub
section G of this discussion will explain the meaning and
application of this method in more detail.
It accounts for both the
chronic and acute noise intrusions in an attempt to be
more reasonable, but it places a greater burder on the EP0.
Section 8.1 concerns the long-time noise exposure (90%
of the time) and Section 8.2 concerns the short time
special
loud exposures (10% of the time). Thi^ allowance for
brief but louder noises found that resistance to enactment
of a noise ordinance is lessened thereby. One disadvantage
of this method is that it requires the EP0 to take a
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7-106e
sufficiently long sample of the noise so that the
percentile levels can be established with some degree
of confidence. Ten minutes is the minimum sample time
recommended and some.communities may monitor for an
hour. In smaller communities, one is not going to close
down a several million dollar plant, employing 2000
people and the mayor's son, based on one sound level
reading. Another disadvantage is that it requires
sampling of the noise, using either expensive equipment
made for that purpose or reading a simple sound level
meter in a special way. The latter, cheaper method has
been used in Lakewood, Colorado on statioaary noise sources
that are highly fluctuating and officials report that it
can be done. They have since bought a statistical distri-
bution analyzer to do the job automatically. In conclusion,
the method is workable and provides for a more realistic
evaluation of the noise intrusions of a noise source,
particularly if it creates fluctuating noise, but it re-
quires more time and effort on the part of an EPO. It is
more applicable to medium-size communities which have less
severe problems and who intend to control not only the
acute noise intrusion but also the chronic intrusions.
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Eventually this method will be made more attractive
inexpensive
when i hand held meters, which read percentile
levels directly, enter the market. This enforcement
method will likely approach the maximum level enforce-
ment method when meters which display the energy average
level (L ) are sold,
eq
A third scheme may be called the ambient-plus method
Here the ordinance is written so that a stationary noise
source is allowed to exceed the existing ambient noise by
a specified number of decibels. Palo Alto, California
such
is a community that has/an ordinance . The
apparent basis for this type of ordinance is that
' i Z t "
if a noise source is below the ambient noise level it
. i j 'ii' i.i i i '> 'i
probably is not a source of annoyance and could not be
identified anyway. There are several critical deficiencies
varying as the ambient noise
in this method. First , it is a relative standard >6nd thus varies
it is not tied to any health and welfare criteria. Secondly,
the relativity allows for an "up the ambient" subversion of
the law: if all noise makers were to make noise simultaneously,
a new ambient would be created. Fortunately, this is an un-
likely event. Thirdly, and more important, the EPO must
noise
measure the ambient/with the noise source in question
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off and then with it on. Turning off factories can be
difficult. Since the ambient level will change through
the day, the choice of measurement time is critical. In
conclusion, this method is most considerate of the noise
maker, he may make as much noise as he likes as long as
he does not exceed the previously existing ambient too
much but, in our opinion, it places an excessive burden
on the EPO in attempting to establish a noise violation.
It also makes problems for the noisemaker who may con-
scientiously wish to control his noise, but does not know when
he has done enough since there is no firm criterion to guide
his efforts.
This method is not recommended.
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B. Solution for Location. We are primarily concerned with
different degrees of annoyance associated with different
often
activities. At home, annoyance is/due to interruption of
rest or sleep, in business it is due to poor speech com-
munication, and in industry, we
wish to protect hearing. (See Section 2 of Chapter 4).
Most ordinances have used this division to
assign noise level limits by land use category as identi-
fied in the zoning code. Two states, New York (Ref. 24)
and Illinois (Ref. 25), have used the Standard Land Use
Coding Manual (SLUCM, Ref. 26) to categorize stationary
noise source zones. Cities have used either broad defi-
nitions, such as Residential (Refs. 1 and 4) or have sub-
divided into more specific land uses within each broad
category. San Diego (Ref. 2), for example, has set three
different limits within residential districts. Salt Lake
City (Ref. 21) has two different limits in residential
zones. Step 7 of Chapter 2 discusses the process of
choosing how to categorize land use for noise purposes.
The location for measurement is another consideration.
It can be at a property boundary, at a fixed distance beyond
the property boundary or at any point beyond the property
boundary. Section 8.1 specifies at or beyond the property
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boundary to permit maximum freedom in choosinq the
measurement site. Note also that the receiving; land
use is where the measurement is to be made, so the
presumption is generally that the loudest levels will
occur on the property line nearest the source. But
if a clever noise maker were to build a wall near that
line the property line may be in corrroliance but other
parts of the receiving property may not be.
Using the receivinq property as the point of
measurement works well when the method of enforcement
is by complaint response. The receiving point is chosen
automatically. Measuring there may work a hardshiD on the
noise maker, and the EPO should be aware of this fact.
The noise violator may comoly by, say, building a wall
barrier; three months later a person elsewhere complains
and he has to build another wall on the other side of his
property and so forth. This problem could be solved by
making the measurement point the sending property boundary
and require compliance at all points, but it would be a very
poor solution as a regulatoryactivity.There may be residences
on only one side and that may be the only side to require
protection. The method generally used is to
require compliance at the point of complaint but to warn the
noise violator that he may be in violation at other points
-------
7 _110
TABLE 8.1 (A) Time Limits in Various Communities for Land Use
Source
Land Use
(Reference No.)
Category
Day
Evening Night
NIMLO (1)
All
7am - 10pm
10pm-7am plus
Sun. & holidays
Lakewood (4)
All
7am - 10pm
10pm - 7am
Illinois (25)
San Diego (2)
Res.
7am - 7 pm
7pm-10pm 10-pm-7 am
Salt Lake City (21)
Com.
7am-10pm
10pm-7am
Ind.
-
All the time
New York City (3)
Enabling
legislation for standards
New York State (24)
Res.
7am-llpm
llpm-7am
Com.
-
All the time
Ind.
—
All the time
San Fran. (14)
Res,Com
7am-10pm
10pm - 7am
Ind.
-
All the time
Chicago (15)
All
All the time
Hawthorne (27)
Baltimore (7)
All
7am-9pm
9pm - 7am
Boston [8)
All
7am-6pm
Other times
(6pm - 7am)
Remember to consider special days, such as Saturdays, Sundays, and legal
holidays. As you can see from Table 8.1(A), very few communities have
standardized their time limits. Stationary sources are purely local problems,
so it is not as important to have standardization as with moving sources,
although we recommend communities near each other standardize as much as
possible.
-------
7-111
human hearing acuity at low frequencies and for low
sound levels. (See Section 3.2.1). Thus, a noise
measurement made on a sound level meter with A-weight-
ing will give you one number x dB(A). It can, therefore,
be read simply and quickly, two factors important to any
EPO. Octave bands, on the other hand, divide the sound
spectrum into several parts. Each part of the
spectrum is an octave wide (upper frequency is twice
lower) and is denoted by the center frequency of the band.
The bands most used are 63, 125, 250, 500, 1000, 2000,
4000, and 8000 Hertz (Hz). There are conditions under
which this finer division of the sound spectrum is
important but, in most cases, such a detailed measure
is neither necessary nor worthwhile. From an EPO point of
view, it is an added complexity. Not only would eight
readings be required, but those readings would have to be
compared with some standard set of values. If only one
of the readings is sliqhtly over the regulation and the
other seven are well below, the EPO either has to interpret
the law strictly or do further study of the data. In any
event, he will have to devote more time than he intended.
-------
7-112
In difficult cases, say where a pure tone is present,
octave or even finer divisions may be necessary. For
example, see Ref. 25 for a discussion of the measure-
ment of a "prominent discrete tone."
When the sound level of the source fluctuates with
time, as it does in many cases, the measurement problem
becomes even more complicated. One may have to develop
percentile levels in each octave band!
For all these reasons (cost, time, detail), we
strongly recommend using dB(A) in preference to octave
bands. If you wish to use a finer division of the sound
spectrum for certain cases, we recommend that the con-
ditions for its use be placed into enforcement regulations
rather than in the ordinance itself. For a thorough dis-
cussion of the merits of A-weighted measurements, see
Reference 28, and for a discussion of octave band measure-
ments, see Reference 29.
References 1, 8, 15, 24, 25, and 27 use octave band
limits and References 2, 4, 5, 7, 14 and 21 use dB(A)
limits. A more complete, but not exhaustive, tabulation
(Ref. 10) shows that 24 municipalities use dB(A) criteria
and 34 use octave band criteria. Most new ordinances use
dB(A) exclusively, as does the U.S. EPA.
-------
7-113
E. Level. The most important part of Section 8.1 is the
choice of sound pressure level in Table 1 (levels G
through L). Since we are primarily concerned with A-
levels,
weighted/ the data given below are either originally
A-weiqhted or are octave bands which were converted to
usually
A-weighting. Residential areas should>toe the quietest
and industrial areas should be allowed to be the noisest.
The actual level chosen will depend somewhat on the choice
of definition for that level, i.e., whether it be minimum,
median, or maximum. Discussion Sections A and G address
that problem and should be read also before numbers are
chosen. A comprehensive compilation of the distribution
of the noise limits chosen by communities for residential,
commercial, and industrial use are shown in Fiqure 8-1-A below
(Ref. 10).
For residential land use, the average of 68 cities
is near 55 dB(A) in the daytime and 50 dB(A) at night
(limits G and H). For commercial land use, the average of
61 cities is near 62 dB(A) in the daytime and 57 dB(A) at
night (limits I and 0), while for industrial land use, the
average is 66 dB(A) in the daytime and 62 dB(A) at night
(limits K and L). From these figures, we can see the
most often used limits as opposed to the average. They are:
-------
7-113a
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-------
7-113b
TABLE 8.IB NOISE LEVEL LIMITS
dB(A) OR EQUIVALENT
COMMUNITY RESIDENTIAL COMMERCIAL INDUSTRIAL
DAY NIGHT DAY NIGHT DAY NIGHT
Baltimore, Md.
55-70
50-65
58-70
53-65
61-
¦75
56-70
San Francisco, CA
55-60
50-55
70
60
70-
¦75
70-75
Boston^ Mass.
60
50
65
55
70
60
Denver, CO
55
50
65
60
80
75
Hawthorne, CA
42
42
-
-
53
53
Loveland, CO
48
45
52
49
56
53
New York
65
45
65
-
80
-
Fountain Valley, CA
50-60
45-55
-
-
-
-
Santa Rosa, CA
55
45
60-65
55
70
70
Billings, MT
55
50
60-70
55-65
80
75
Missoula, MT
60
55
65
60
70-
¦80
65-75
Coral Gables, Fla.
35-40
32-35
45
40
50
45
Helena, MT
55
50
60
55
80
75
Wheatridge, CO
37
37
-
-
-
-
Hermosa Beach, CA
45
45
55
54
65
65
Grand Rapids, Mich.
45-52
38-45
52-63
45-56
-
-
Albuquerque, N.M.
55-61
55-61
62-66
62-66
-
-
San Diego, CA
50-60
45-55
60
55
70-
•75
70-75
Colorado
55
50
60
55
70-
¦80
65-75
Illinois
55-62
45-62
55-62
45-62
61-
¦70
51-70
NIMLO
45
45
53
53
58
58
Chicago, 111.
55-61
55-61
62-66
62-66
-
-
Dallas, Tex.
56
56-63
56-
-70
Minneapolis, Minn.
55
62
North Carolina
55-60
50-55
70
70
Lakewood, CO
55
50
60
55
80
75
Inqlewood, CA
55
45
65
65
70
70
Salt Lake City, Utah65 55^6070 65 75^80 75^80
-------
7-114
Most Often Used Limits dB(A)
Day Night
Residential 55 45-50
Commercial 60-65 55-60
Industrial 70 70
A U.S. EPA document (Ref. 6) gives some levels which
- of noise
relate to the health and welfare effects/on people.
For residential areas outdoors, hospitals and educational
facilities, it recommends a 24-hour average of 55 dB(A).
This average is a special one, called Day-Night Average Noise
Level, and it applies a 10 dB(A) penalty (addition) to noises made
between 10 p.m. and 7 a.m. (See Section 3.2.6).
F. Duration. How long a noise disturbance lasts plays an important
listener -
role in determining the annoyance of an unwilling / and the
not
likelihood of a complaint to authorities. We are /discussing here
the issue of continuous vs. discontinuous noise (See Section
Here
3.2.4 for definition and further discussion). / we are concerned
continuously.
with sounds that occur/for extended periods of time,
whether that sound is steady, fluctuating, intermittent,
cyclically, varying, or impulsive. Any noise which exists for
long periods of time (hours, days or weeks) usually elicits
more annoyance that the same sound for shorter periods of time.
-------
7-115
In order to protect the public from continuous noise,
the question of long-term monitoring arises. For most
communities, long-term monitoring is neitherfeasible nor
practical. What then, is an optimum measurement period
in order to establish that a source creates continuous
noise intrusions? The U.S. EPA is recommending the Day-
Night Average Noise Level to measure this long-term
exposure and it is a 24-hour measure. A noise control
program would be severely impaired, however, if every
stationary noise source had to be measured for a period
this long. We recommend that a minimum measurement
period of ten minutes be established - the "x) in
usually
Section 8.1. Ten minutes is/sufficient to establish a
valid measure of the various percentife levels for a
fluctuating continuous noise source. When the source is
off for extended periods of time, it will be necessary to
extend the measurement period to encompass the on-off
cycle. Thus, the provision above is written to allow
flexibility of the measurement period in order to establish a
valid measure of the time characteristics of the noise
source.
The ultimate validity of the measurement period
-------
7-116
chosen for a particular noise source will be established
in a court of law. and must be the subject of later documents;
here are are only concerned with writing an ordinance pro-
vision which provides the needed flexibility.
For many stationary noise source problems, we
suggest periods on the order of one hour and many of the
definitions appearing in Section 3.2 reflect this sug-
gestion. The discussion under Section 8.2 returns to
this problem.
G. Steadiness of Level. The noise level, as measured on the
output of a sound level meter, at every point in a community,
will vary with time. Some fluctuations will be due to the
source in question and some will be due to extraneous sources,
such as passing vehicles. The extraneous sources are eliminated
generally by the EPO listening to the events around him.
Accounting for fluctuations of the noise source being observed
is a question that has not been seriously addressed to date.
The question can be avoided by using the maximum level method
of enforcement. To use the recommended provisions of Sections
8.1 and 8.2, however, it is necessary to address this problem.
When the noise is steady (see definitions) there is
-------
7-117
little difficulty in determining the sound pressure level.
When the source fluctuates or is intermittent (e.g., the
noise from rock music in the beer hall across the street),
there are many sound pressure levels and we must consider
the amount of time spent above any given level. To describe
chronic noise exposure we have chosen the level ex-
ceeded 90% of the time (See Section 3.2.17 for definition)
Tables B.l
as the descriptor of the number in / above. Regulatory
officers in the field often attempt to measure this level
subjectively without being aware of it; they attempt to
eliminate all extraneous sources, including any brief but
loud sounds emitted by the noise maker in question. One
reason for choosing this level is to eliminate from Section
8.1 any consideration of these brief but loud sounds from
any source. Objections to regulations on stationary noise
sources many times center around the fear of stopping normal
community activities: the yelling of children in a school yard
or the mowing of a lawn. Using the 90 percentile level as a
measure will virtually eliminate such potential difficulties,
as the following sample situation will show.
-------
7-118
EXAMPLE MEASUREMENT PROBLEM
Consider the case where the ambient noise in a
residential community is that normally present, and then a
neighbor begins to mow his lawn adjacent to your property.
How can the time history of a sound level meter output be
used to establish whether an offense has occurred? The
sound level meter is set up at the center of the 80
foot property line. The lawn to be mowed is 80 feet long
and 40 feet deep. The neiqhbor owns a lawnmower that
generates 80 dB(A) when measured at 25 feet. Now, as he
mows the lawn, this noise source moves closer to and farther
from the measurement point to produce a fluctuating noise at
the microphone and at your ear. When he is closest to the
microphone, the sound level will be 102 dB(A) and when farthest
away, it will be 72 dB(A). A typical time history during the
mowing period and before or after mowing might look like that
shown in Figure 8.IB. The upper trace shows the peaks of noise
associated with successive passes of the lawnmower. As the
mower moves farther away, these peaks become less intense. At
one point, a motorcycle passing on a nearby street intrudes on
the lawnmower noise. The levels are not meant to be accurate
-------
" — uht spent ftETwesn 1°[ av\e\ UO c\&(A)
Dofc'NV fAoVMilACr- pEWOD
trt>
A - ' t.K M 0\A. 1^ (y
flCotc 5.\ f5
-------
7-119
in this sketch. After the mowing is done, the lower
trace applies - the levels are lower and are typical
of a residential community.
There are two sampling methods shown in the Figure.
On the upper trace is shown the more accurate (and
expensive) method. A device is attached to the sound
level meter which has a number of storage elements that
record the time the noise is between two pre-chosen limits,
in the Fiqure they are 79 and 80 dB(A). By tallying the
time spent in each range, it is possible to determine which
noise levels occur most often; we will discuss how this in-
formation is used below. The lower trace shows a somewhat
less accurate (less expensive] method where the sound level
is sampled at certain intervals of time (say once each 10
seconds), and the number of times a certain level is observed
is recorded. In each case, it is possible to normalize the
individual data to an overall time period, say one hour. For
the first method, if 79-80 dB(A) occurs 180 seconds durinq an
hour, then it occurs 5% of an hour. If we sample every 10
seconds, then there will be 360 samples in one hour, and if
79 dB(A] occurs 10 times in the hour period, we estimate it
occurs 2.8% of an hour. The lawnmower takes 20 minutes to mow
-------
(C
o>
I
2b hlHuTE
LMN MdWjSg
SPL dE><0
-------
7-120
the lawn described above and then stops. The resultant
distribution of sound levels over the hour is shown in
Figure 8.IE. The solid lines indicate the amount of time
spent at the higher levels caused by 20 minutes operation
of the lawnmower. If the lawnmower were off for the hour,
the solid lines would be all longer, so the total would
once again be 3600 seconds. Normally a fiqure like this,
called a statistical distribution of sound levels, is not
used; rather a cumulative distribution is used. To qet a
cumulative distribution, we sum up the percent of time a
level is exceeded starting at the highest levels. From
Figure 8.IE, we can say 92 dB(A) was exceeded 0% of time
(which is not precisely true since it once hit 102 dB(A),
but it is not important for our present purposes). 90 dB(A)
was exceeded six seconds or 0.16% of the time, and so forth
until we get to 45 dB(A) where we can say it was exceeded
100% of the time. There are three exceedance levels that
are in common usage: the level exceeded 90% of the time
(Lno), the level exceeded 50% of the time (Lcn), and the
90 oU
level exceeded 10% of the time (L^g)-
Figure 8.IF shows how the.cumulative distributions
of sound level may be graphed. The data from Figure 8.IE
-------
7-121
is shown in this new figure as th.e 2Ckminute lawnmower
on time. For our problem, we see that when no lawnmower
is on, the Lgg is 50 dB(A), and the L is 62 dB(A), mostly
due to occasional passing motor vehicles. If the neighbor's
lawnmower were to run, the levels would increase in
accordance with the following table:
-------
L&MMMCI/VER
20 Ml Ml
Motse
FIGURE 8.ID
-------
7-122
Lawnmower LQn Lc. L1n
on time yU 50 10
(minutes)
0
50 53 62
20
50 57 80
30
51 71 82
60
75 78 85
We see from this table that L^q is a
sensitive measure of the shorter duration
loud levels, the acute noise intrusions,
and the Lqq is a sensitive measure of
the chronic noise intrusions. By putting
a limit on domestic power equipment (See
Section 6.2.22), we control the L10 levels>
and the present provision can be used to
control the Lqq levels or, alternatively, control
time a given piece of equipment is allowed
to be used . The
L5Q value is similar to Lqq in some respects
and can be used to apply more stringent time
limits.
-------
7-123
This discussion has shown that if the LgQ value is
chosen, normal community activities, such as lawn-
mowing, can occur so long as they are in compliance
with other provisions of the ordinance. On the other
hand, continuous noise sources will control the L
90
value and will be regulated. You should also note
that if we were to interpret levels given in the
previous discussion section as maxima, say 55 dB(A)
in residential zones, no one could mow their lawn or
perhaps start their car.
-------
7-124
Table 8.1.C is intended.
To tie this discussion to Discussion Section E on
Levels., . The levels
measured in Los Angeles, Detroit, Boston, Inglewood,
Dusseldorf, New Orleans, Ottawa, Seattle, Tokyo, and
Vienna (Ref. 30) are presented there.
Table 8.1C Typical Lgg Levels in Various Communities
Residential Commercial Industrial
Day
Night
Day
Night
Day
Niqht
43
38
50-60
45-55
60-70
50-60
55
41
55-65
45-55
66
47
50-60
40-50
65
52
40-50
35-45
45-57
34-47
38-60
30-45
The Discussion Section for Section 8.2 shows that the
L5g is generally 5 dB(A) above the Lg0, and the L1Q
value is about 14 dB(A) above the Lgg for normal community
activities. Comparing the data above with the limits shown
in Figure 8.1A or Table 8.IB, suggests that the legal limit
an
in already existing ordinances must be interpreted as/ Lgg
or else the entire community may be in violation.
-------
7.125
H. Source Identification. Whenever a noise
source is sufficiently loud to stand out over the back-
ground noise, it can be identified quite readily. When
the noise source is continuous and very loud, it is^ the
background noise and once again can be identified easily.
A typical factory, however, will emit noise which is
occasionally masked by aircraft or car noise. If the
source is continuous, even though it fluctuates, and
can be Identified only during periods when other
then
transient sources are quieter, it can foe established
that the continuous source is the most probable cause of
the Lgg level. There are other complexities
associated with source identification, and further dis-
cussion will be left to a later document. For present
purposes, it is enough to say that almost all source
identification problems can be resolved.
-------
7-126
Section 8.2 Duration Correction
(a) It shall be unlawful for any person to operate,
or permit to be operated, any stationary source
of sound within any land use category which
creates a sound level of (x) dB(A) greater than
the levels set forth in Section 8.1 for the
ambient sound level for more than 10% of the
measurement period, which shall not be less
than 10 minutes. For the purpose of this
section, the ambient sound level shall be
measured when the source is not operating.
(b) Notwithstanding, subsection (a) of this
section, it shall be unlawful for any person
to operate, or permit to be operated, any
stationary source of sound within any resi-
dential land use category which creates a
sound level of greater than (y) dB(A) for
more than 10% of any measurement period,
which shall not be less than 10 minutes.
(Definitions 1, 2, 20, 27, 35, 37 required)
-------
7-127
Discussion: Discussion Section G of Section 8.1 covered
the problem of a fluctuating noise source intruding on
the ambient noise in a community. Traditionally, a
correction for intermittency of the source was given.
For example, if a noise source operated only 5% in any
one hour period (3 minutes), the source might be allowed
10 dB(A) more than the limit stated in Section 7.1.
NIMLO (Ref. 1) has recommended such a provision, and San
Diego (Ref. 2) has adopted one similar to that recommendation
Discussion Section G of Section 8.1 described
the various percentile (cumulative distribution) levels, such
as Lgg, Lgg, and L^. These levels are measures of the
duration of the sound. Section 8.1 attempts to regulate
the chronic noise intrusions by relating them to the nintieth
percentile noise levels. This Section was written to regulate
the more acute noise intrusions by relating them to the tenth
percentile noise levels. This provision, then, is similar
in concept to the NIMLO recommendation, but it contains only
one correction for duration. The NIMLO recommendation has three
ordinance
percentile levels and the San Diego/has six percentile levels.
At the present time, we recommend using only one percentile
level, Ljg, but if you wish to add more,we would suggest
-------
7-128
addinq L next, and the above section could easily
be modified to include this addition.
It will be necessary to choose the "x" and "y"
values for this section. To get a feel for them, we
present in Figure 8.2 data obtained from measurements
made in a large number of communities. The Figure is
arranged to show the difference between the L^, L^q,
L5q (generally denoted Ln), and the Lg0 levels. The
the
dashed line is/average value through the data, and we
see that the is about 14 dB(A) greater than the
Lgo value. If, for example, Lgg = 45 dB(A) then we
might expect L to be 59 dB(A). Also shown in the
Figure are the curves faired through the intermittency
corrections of NIMLO and San Diego when we interpret
their base levels as Lgg. We see that their allowances
are more restrictive than the variations normally found
in the community. This does not mean that their limits
are unenforceable, but rather implies that the sources
regulated may not be the source of the loudest noises in
the community.
-------
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cinure 8-2
-------
7-129
Subsection (a) of Section 8.2 limits the difference
between and Lgg, a relative limit. Now LgQ can be
generated by two sources; the general community noise
or the noise maker in question. The provision is written
so that if the noise maker causes the Lgg which just meets
Section 8.1, he would be allowed to make an L^q which is
x dB(A) greater than the allowed limit. If the community
generates the Lgo, which is most likely less than the
limit in Section 8.1, the noise maker will have to reduce
his acute noise intrusions accordingly. Subsection (b)
of Section 8.2 puts an absolute limit on Ljq in resi-
dential areas to preclude degradation of the noise en-
vironment in places where the LgQ levels are already hiqh.
To clarify the meaning of this Section, consider a
typical case. Say SubSection (b) is written to be con-
sistent with the Federal Highway Administration's PPM 90-2
which limits L^g to 70 dB(A) or less at residences. Say
further that the community limits the noise received 90%
of the time in residential areas to 55 dB(A) during
the day and 50 dB(A) at night. If one chose "x" as
20 dB(A), and if the noise maker just met the Lgg limits,
he would be allowed = 70 dB(A) during the day
-------
7-130
and 70 dB(A) during the night
If the noise source were
an intermittent one (chain sawing, qravel loading),
then the community general noise would probably determine the
Lgg. Say this noise was 58 dB(A) during the day
(already over the legal limit), the noise maker would
be limited to Ljq = 70 dB(A) (Subsection b). Say at
night the community general noise dropped to 35 dB(A),
then the noise maker would be limited to L- = 55 dB(A)
10
(Subsection b).
Subsection (cj) is based on the Noise Pollution Level
concept which states that annoyance is based on the
absolute noise level and the variation', between the
highest and lowest levels. The duration correction in
this recommendation is related to that variance which
can be expressed as:
(L - L
A = l\ - 1 W 10 90 - v + *77
^ 10 90' 50
where x is the value appearing in Subsection a. The
variance term is put in tabular form below.
X 5 10 15 20 25
OT5 11.5 18.5 26.5 35
be
We recommend that "x"/between 10 and 20 dB(A).
-------
7-131
Section 8.3 Correction for Character of Sound
(a) For any stationary source of sound' which emits a pure
tone, cyclically varying sound or repetitive impulsive
sound the limits set forth in section 8.1 shall be
reduced by (x) dB(A).
(b) Notwithstanding compliance with subsection (a) of
this section, it shall be unlawful for any person
to operate, or permit to be operated, any stationary
source of sound which emits a pure tone, cyclically
varying, or repetitive impulsive sound which is
plainly audible or creates a noise disturbance.
Definitions 5, 13, 19, 20, 21, 26, 35 required)
Discussion: The emission of impulsiveand repetitive noise is more
annoying than the typical noise emitted by stationary noise sources
and should be subject to more stringent restrictions. NIMLO (Ref. 1)
recommends 5 dB(A) as a practical value for "x." Note that this number
is a reduction in the limits.
The enforcement of regulations on pure tones is more difficult
But in terms of the higher degree of annoyance associated
with those tones, this difficulty is worth overcoming. The definition
(Section 3.2.26) is written so that listening will suffice in simpler
cases, but when it is critical to establish the presence of a pure tone,
or finer may
a 1/3 octave band analysis / be necessary. In smaller communities,
it may be possible to take a tape recording to a hospital, university, or
-------
7-132
government laboratory to have it analyzed. Tape recordings are also
valuable records to have for the other sources of noise, they do have
to be instrumentation quality but just high fidelity since only the
time history is important.
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7-133
ARTICLE IX MOTOR VEHICLE SOUND LEVELS
Section 9.1 Maximum Permissible Sound Levels of Motor Vehicles
No person shall operate a motor vehicle on a
public right-of-way at any time in such manner
that the sound pressure level emitted by said
vehicle exceeds the levels set forth in Table 1
when measured at the location established by
Section 9.1.1. This section shall apply to all
motor vehicles, whether publicly or privately
owned, that are duly licensed.
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TABLE 1. Motor Vehicle Noise Limits
Sound Pressure Level, dB(A)
Vehicle Class Speed Limit x mph Speed Limit x mph Stationary
or less or more Run-up
Federally Registered Interstate
Motor Carrier Vehicle of manufacturers
gross vehicle weight rating of 10,000
pounds or more
(86 if" X") (90 if" X")
A is 35 mph B is 35 mph
88
All other motor vehicles with a manu-
facturers gross vehicle weight rating
of 10,000 pounds or more, and any com-
bination of vehicles towed by such
motor vehicle
Any motorcycle other than a motor-
driven cycle
C D
E F
Any other motor vehicle and any com-
bination of vehicles towed by such
motor vehicle
(Def. 1, 14, 13, 20 required)
G H
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Discussion: Traffic noise is the major noise source in
almost all comnunities, so choice of the above limits
will play a large role in the ultimate levels found in a
community. In addition, motor vehicles require some form
of standardization from community to community. Further,
the motor vehicle industry is powerful and can exert a
strong influence on the passage of noise ordinances. For
these reasons, your community should choose the above
values carefully.
Use of the dB(A) is
strongly recommended. The posted speed limit given above
as "x" is normally 35 mph, but there are communities that
delete the higher speed category entirely and use 45 mph
or less to cover the whole municipality.
The provisions of this article are intended to control
licensed motor vehicles operating on public rights-of-way
only; a later section addresses off-highway vehicles.
Depending on the levels chosen, there could be some in-
equities in its enforcement, such as trapping a heavy truck
accelerating uphill from a stop light. These conditions are
so varied that methods for their avoidance must be handled in
enforcement regulations and not in the ordinance. The measure-
ment distance is important and is provided for in Section 9.1.1.
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TABLE 9.1 Present Operating Vehicle Noise Limits at 50 feet
or equivalent, dB(A)
less than
more than
Community
Posted Speed
Posted Speed
Trucks
Motor
Trucks
Motor
cycles
6K
8K
10K
Cars cycles
6K
8K
10K
Cars
California
86
*
76 *
82 *
88
82
86
Colorado
(82)
(74).
(77).
86
82
86
90
86
90
Connecticut
86
76
82
90
82
86
Indiana
86
76
82
90
82
86
Pennsylvania
90
82
90
92
86
92
DOT recommend
86
76
82
88
82
86
Billings, MT
82
74
74
82
74
74
Boulder, CO
82
74
74
-
-
-
Chicago, 111.
86
76
82
90
82
86
Grand Rapids, MI
86
76
82
90
82
86
NIMLO
80
80
87
78
87
-
-
-
-
-
Oahu, Hawaii
86
73
73
86
83
83
Lakewood, CO
82
74
74
-
-
-
Denver, CO (prop)
82
74
74
-
-
-
New York City
86
76
82
90
82
86
California
Cities
-
STATE PREEMPTED -
Salt Lake City,
Utah
82
74
74
-
-
-
Kalamazoo, MI
74
74
82
74
74
78
78
86
78
78
•k
Applies on level streets
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The noise limits chosen for discussion in this section
are based on 50 feet, even though it has been found that
50 feet is a difficult distance for measurement in a
community. (See discussion on Section 9.1.1). If your
conmunity wishes to use 25'feet in the ordinance, then
the values discussed in this section should be increased
by 6 dB(A). When reading ordinances, it is important to
distinguish between operating limits and limits associated
with prohibitions on the sale of new vehicles. The former
and to be
limits are those used in this section /are/applied
on the right-of-way Conmunities are permitted to
regulate vehicles in this mode of operation, with the
exception noted in the section on trucks below.
Chicago (Ref. 15)
has both types at the present time, Boston (Ref. 8) has
only sale-of-new-vehicle limits, while most communities
have operational limits only. Table 9.1 below gives
a list of communities and states that have operational
limits on vehicular noise. Several states
have enacted operational limits. California, with an
active enforcement program, has preempted the entire state
so communities must adopt similar levels if they wish to
enforce vehicular noise limits. Colorado, with no enforce-
ment program, specifically permits municipalities and counties
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the right to enact and enforce more stringent standards.
Trucks. The ability of communities to control truck noise will be
limited by Federal preemption under Section 18 of the Noise Control Act
of 1972. The U.S. Environmental Protection Agency (Ref. 33)
instituted standards to control the noise emitted by trucks operating in
interstate commerce (See Chapter 6 for a discussion of preemption.) A
preliminary draft of that standard indicates that trucks with gross
vehicle weights greater than 10,000 pounds will be restricted to 86 dB(A)
or less at speeds less than 35 mph and to 90 dB(A) or less at speeds
greater than 35 mph when measured at 50 feet. Federal preemption per-
taining to interstate commerce does not preclude communities from taking
effective action against truck noise* Although the law prohibits local
communities from having standards,which control the noise resulting from
the operation of interstate motor carriers, that are different than the
Federal standards. The Act also states that "nothing ... shall diminish
or enhance the rights of any state or political subdivision thereof to
establish and enforce standards or controls on levels of environmental
noise or to control, license, regulate or restrict the use, operation or
movement of any product" if the EPA Administrator determines it is not in
conflict with regulations promulgated under Section 18. Since the standard
proposed will control only noise on highways, communities would then be
free to: establish curfews on truck movements; establish truck routes;
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have special truck lanes and speed limits; require adequate mufflers;
to limit the number of trucks at a facility, and to control truck
numbers by licensing. In general, if the wheels of the interstate
carrier truck are rolling, then the community cannot control the
structure of the truck to reduce noise.
Boulder, Colo. (Ref. 34) has had extensive experience with a
noise ordinance that is the most restrictive on truck noise, and
reports(Ref. 35) that 82 dB(A) is a workable limit due to the minimum
2 dB(A) tolerance given to offenders (similar to the practice of a
5 mph tolerance on speed offenses). As can be seen in Table 9.1,
many communities have chosen 82 dB(A) as their limits also. California
uses that limit on level streets (Ref. 40). In Boulder they found
that 5% of the trucks monitored in 1972 were in violation, and 8% in
1973, and most in violation had no mufflers. This lower legal limit
is apparently applied judiciously by not monitoring at points where
trucks in low gear have their engines under high load. An EPA
document (Ref. 33) indicates that, on a national basis, about 25%
of the trucks moving under 35 mph would be in violation of an 84 dB(A)
limit, but no information is given on the percentage of these vehicles
sampled which did not have the legally required mufflers. The same
document also shows that virtually no trucks moving uniformly on a
level roadway under 35 mph exceed 85 dB(A). The results suggest that
legal limits between 82 and 84 dB(A) (84 and 86 dB(A) with enforcement
tolerance) in municipalities are practical values for C.on Table 1.
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At high speeds the problem is considerably different. Ref. 33
indicates that about 20% of the trucks will exceed 90 dB(A). Many
of these tests were made at freeway speeds which skews the information
to the high end. It is recommended that if your community proposes
to control truck noise at high speeds, they should make a series of
measurements that relate to the upper speed limits in effect, before
they choose level D.on Table 1.
Cars. Cars at the low speeds found in communities generally are
quite quiet. The California Highway Patrol (Ref. 36) has an extensive
compilation
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7 -141
of data taken on passenger cars operating on public
rights-of-way. Table 9.2 below gives the results
for a sampling of 9,296 cars in California.
Table 9.2 Data on Passenger Cars
Measured
Max. dB(A) 86 85 84 83 82 81 80 79 78 77 76 75 74 73 72
% exceeding
below 35 mph 0 0 .01 .02 .03 .04 .06 0.1 0.2 0.3 0.3 0.7 1.3 2.4 3.3
% exceeding
over 35 mph .04 .04 0.1 0.2 0.5 1.0 1.6 2.9 4.6 9.0 14.0 - - -
level G on Table 1
Table 9.2 shows that if the limits for / were 82 dB(A) for
speeds less than 35 mph, only one car in 3000 would be in violation;
the EP0 will not be busy nor will he be making a dent in the
noise problem. He could be used more profitably in other ways,
if that limit is set. At 74 and 76 dB(A), about 1% of the
vehicles will be in violation. Boulder (Ref. 35) has found
2% in violation in 1972 and 1.5% in 1973, and these were mostly
high performance vehicles or ones modified to simulate high
performance.
In 1973, the California Highway Patrol measured the noise
from nearly one-quarter of a million vehicles weighing less than
6000 pounds and moving less than 35 mph, and found that only 1.41%
were in violation (3,608) of the 76 dB(A) limit. This result further
confirms the results obtained in other communities. They noted in
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7-14?
their 1973 Enforcement Summary that 66% ofthose in violation had modified
exhaust system. Community noise enforcement on cars amounts to control
of modified or poorly maintained vehicles.
(H on Table 1)
At higher speeds, the limit / must be higher. As with trucks,
it is difficult to apply the high speed data to communities because
some data were obtained at.freeway speeds. The most common limit
used is 82 dB(A). Table 9.1 and the data in Table 9.2 indicate that
1/2 percent were in violation of that limit, very similar to the per-
cent in violation for the 76 dB(A) limit below 35 mph. The dependence
of vehicle noise with speed is known (Ref. 37) and using this fact, one
can show that an increase of speed from 35 mph to 55 mph (the present
national limit) will cause an increase in noise of 6 dB(A). If one
chose 74 dB(A) for the lower speed, then 80 dB(A) would be reasonable
for the upper speed, while a limit of 76 dB(A) would correspond to
82 dB(A) for higher speeds. In 1973 California measured over 400,000
cars and found 1.57% were in violation over 35 mph. Again modified
exhaust systems were the primary cause of violation (80%).
Motorcycles. A community questionnaire (Ref. 12) has shown that in
smaller size communities, motorcycle noise is by far the greatest
source of annoyance. The recent scarcity of gasoline has increased
the sale of motorcycles greatly, so one should expect a larger
number of motorcycles on the road in the near future. Even prior
to the fuel crisis, the growth of the motorcycle population relative
to the total number of vehicles has been significant. In Boulder
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County, Colorado, the motorcycle population rose from 1.8%
of the total in 1960 to 6% of the total in 1973, and it
doubled in 1974. (See Figure 9.1) Due to the inherent
openness of the engine and
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the small amount of space available for mufflers, motorcycles
can be noisy. The sound level can vary
greatly with operating method, full throttle can be 20 dB(A)
higher than cruising operation (Ref. 38). The primary noise
source is the induction of air and the expulsion of exhaust
gases (Ref. 37). Figure 9.2 shows the distribution
of motorcycle noise collected from several sources, some un-
published. It is important to note that this data is only typical
of motorcycles operating normally on a street. The opposition
of many motorcycle-oriented groups to the levels set in noise
ordinances is based on data they have obtained from manufacturers.
These manufacturers generally do a maximum acceleration test in
accordance with the Society of Automotive Engineers Recommended
Practice J 331 or the California Highway Patrol Test (Ref. 39),
and the associated noise is higher.
The most used legal limit is either 82 or 74 dB(A).(See
level E
Table 9.1 for speeds less than 35 mph { / in our provision).
that
The authors suspect/the wide difference is due to some com-
munities not considering a motorcycle to be any different than a
passenger car. California (Ref. 40) limits motorcycles to 77 dB(A)
on level streets. Comparing these values with Figure 9.2
suggests that 7% would be in violation for a limit of 74 dB(A)
(applying a 2 dB enforcement tolerance) and 1.7% would be in
violation for a limit of 82 dB(A). The data are not too reliable
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7-144a
AO 50 60 eo 100
population, Thousand
s
FIGURE 9.1 Number of Registered Vehicles in Boulder County,
Colorado as a function of, Population
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7-144b
o -
o -
o =>
CO !
ID «
^ i 0
W in
Z U
h2 13
j2 u
£> t
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7-145
however, due to the small number of samples. Over a two-year period
Boulder (Ref. 35) has found that about 0.4% of the total number of
vehicles monitored are motorcycles in excess of their 74 dB(A) limit
(which because of a 2 dB enforcement tolerance is actually 76 dB(A).
Knowing that 6% of the vehicles are motorcycles, these data suggest
that approximately 6% of the motorcycle population would be in
violation, which is not too different from that estimated above.
In 1973, the California Highway Patrol measured 3,254 motorcycles
at speeds under 35 mph and found that 10.0% were in violation, again
most violators had a modified exhaust system.
At higher speeds, the most common limit is 86 dB(A) (see Table 9.1).
This level relates to F in our ordinance provision. Figure 9.2 suggests
about 2% of the motorcycles will be in excess of 88 dB(A). If one con-
siders a motorcycle to be no different than a passenger car and applies
the most common limit of 82 dB(A) from Table 9.1, we find that about 6%
of the motorcycles will be in excess of 84 dB(A).
In 1973, the California Highway Patrol measured 4,884 motorcycles
at speeds greater than 35 mph and found that 15.3% were in violation
which was considerably larger than 6%.
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9.1.1 Measurement Distance
ALTERNATIVE 1
For the purpose of Section 9.1, the standard
measurement height shall be four (4) feet (1.2 meters)
and the standard horizontal measurement distance from
the center line of the traffic lane being monitored
shall be fifty (50) feet (15 meters). Whenever it is
not feasible to use fifty (50) feet, the distance may
be shortened to twenty-five (25) feet (7.5 meters), in
which case the values in Table 1 of Section 9.1 shall
be increased by 6 dB(A).
ALTERNATIVE 2
For the purpose of Section 9.1, the standard
measurement height shall be four feet (1.2 meters) and
the standard horizontal measurement distance from the
center line of the traffic lane monitored to the micro-
phone shall be fifty (50) feet (15 meters). Measurements
for the purposes of enforcing Section 9.1 may be taken at
a horizontal distance from the center line of the traffic
lane being monitored from twenty-five (25) feet to one
hundred (100) feet, and the correction factor applied to
the limits set forth in Table 1 of Section 9.1 shall be as
set forth in Table 2.
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Table 2
Measurement
Distance (feet)
Correction to
limits
25
28
32
35
40
45
50
56
63
70
80
90
100
+6
+5
+4
+3
+2
+1
0
-1
-2
-3
-4
-5
-6
Piscussion: The numbers in Section 9.1 have no meaning
unless the measurement distance is specified in the
so this subsection must be included with the main section,
ordinance / For the land use category levels, the
property boundary was used. Here we need to specify a
distance from the traffic lane monitored. California
(Ref. 40) established a distance of 50 feet from the
center of
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the lane for measurements. Since they were early in
monitoring,other states and communities have tended to adopt
also.
50 feet/ In addition, most vehicle noise data are obtained
at 50 feet or normalized to 50 feet before presentation. On
a^highway, 50 feet is suitable, but within a community a 50-
foot distance is hard to obtain without excessive interference
from reflecting structures. Salt Lake City (Ref. 41), a
community of about 250,000, estimates they have virtually no
locations where 50 feet can be used as the measurement distance.
They use 25 feet exclusively. Missoula, Montana; Lakewood,
Colorado; Boulder, Colorado; Colorado Springs, Colorado;
Helena, Montana; and New York City all use 25 feet. NIML0
(Ref. 1) also allows for 25 feet measurement distance. A
recent study for the California Highway Patrol (Ref. 42) has
shown that correction factors can be applied to make valid
measurements at distances other than 50 feet, but not less than
25 feet. Peoria, 111. (Ref. 10) and San Diego (Ref. 2)
apparently have used these results to specifically allow for a
variable measurement distance in their ordinances and their
Table 2 in
provisions appear as/Alternative 2 in this Section. Ref. 42
shows that a 6 dB(A) correction is valid for the change from
25 feet to 50 feet as was suggested in the discussion on
Section 9.1.
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It is recommended that your community consider the
potential for an adequate number of measurement sites at
50 feet. If you find they are insufficient, you may consider
writing Section 9.1 with 25 feet in mind by raising the limits
6 dB(A). A site can be considered good if the ambient level
is 65 dB(A) or less, and all large plane reflecting surfaces
are at least 50 feet away.
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7-149a
250
^PRE-E?
-EXPOSURE
N \ 24HRS /¦
Xv
30 SEC
1
500
1000 2000
HERTZ (HZ)
4000
8000
Figure 6.2.10
Hearing levels measured at various times after a 2-hour
exposure to a broad-band noise at 103 dBA as compared
with pre-exposure determinations. (Single subject data
taken from the Public Health Service laboratory in
Cincinnati, Ohio).
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Section 9.2 Maximum Permissible Sound Levels for
Vehicles Operating off Public Rights-of-way.
The maximum sound level emitted by vehicles
operated in any place except public rights-of-
way shall be as provided in Table 3 below.
These shall include all vehicles intended to
carry persons, whether publicly or privately
owned, or whether duly registered or not.
Table 3 Vehicle Noise Limits
Sound Pressure Level
Vehicle Class dB(A)
Watercraft A
All other vehicles B
Discussion: With the increased use of the small internal com-
bustion engine for all forms of transportation, whether commercial
or recreational, noise sources can penetrate the once quiet areas
on lakes and in parks, open spaces, mountain resorts, and so forth.
This provision is intended to control these sources by regulating
their maximum operating noise level. We shall discuss each
separately.
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Motorboats. There are two major ways to handle motorboat noise.
Section 6.2.20, Alternative 1, treats the boat as stationary noise
source. The advantage of this approach is that a measurement could
be made from shore, the disadvantage of that method is that the boat
passage is really an acute noise intrusion, which is best handled by
limiting the maximum noise. This Section overcomes that disadvantage
by treating motorboats as passenger-carrying vehicles and restricting
their maximum noise at a specified distance. The disadvantage of the
present method is that a monitoring boat is required, unless a con-
•k
venient pier is available. Chicago (Ref. 15) regulates motorboat noise
and has set A above to be 85 dB(A) prior to 1975 and 76 dB(A) afterwards,
when measured at 50 feet. Thus, Chicago requires motorboats to be as
quiet as normal passenger cars. Grand Rapids, Michigan has followed
Chicago (Ref. 44)
Off-highway Vehicles. These are land vehicles such as snowmobiles, go-
carts, mini-bikes, dune buggies, all-terrain vehicles, and trail motor-
cycles. One significant factor that differentiates them from other motor
vehicles is that the users are directly exposed to the vehicle noise with-
out the protective outer shell existing on normal vehicles. Thus, consi-
deration of the legal limits on their noise should include the exposure
of the user, as well as the listener. At least 15 states have laws regu-
lating off-highway vehicle noise (Ref. 45). Table 9.3 below sets forth
current and future limits for off-highway vehicles.
*Sirice there has not been much enforcement experience with watercraft,
we cannot, at the present time, recommend one method over the other.
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7-151a
TABLE 9.3
Off-Highway Vehicle
Noise Limits
at 50 Feet
Community
Vehicle
Operating
Limit
Sale
Prohib.
Future
Year Level
Connecticut
all
82
1975 73
Massachusetts
snowmobiles
73
New York
snowmobiles
73
Montana
snowmobiles
75
Utah
motorcycles
all others
92.
82
California
all
88
1975 86
Colorado
all
84
Iowa
snowmobiles
82
82
Michigan
all
82
New Hampshire
all
82
1978 73
New Mexico
snowmobiles
86
Ohio
snowmobiles
82
Oregon
snowmobiles )
all terrain)
88
Vermont
snowmobiles
82
Washington
snowmobiles )
all terrain)
88
Minnesota
snowmobiles
82
1974 73
Wisconsin
all
82
82
1975 78
Grand Rapids, MI
82
73
Billings, Mont.
all
74
Salt Lake City
recreational
82
Missoula, Mont.
all
80
New York City
motorcycles
all others
82
76
San Francisco
regis, motorcycles 77
other regis.
vehicles 74
off-highway
vehicles 70
Chicago
snowmobiles
all other
82
82
73
82
1975 73
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It appears that most present limits are set at
82 dB(A) and in several instances will be lowered to
73 dB(A) to be compatible with standard passenger car
limits. The snowmobile industry (Ref. 46) recommends
a manufacturer's standard of 82 dB(A) before 1975 and
78 dB(A) afterward but only for vehicles intended for
use by children under 12 (Class II). Class I vehicles
for competition are recommended for exemption. Ref. 47
indicates that prior to 1971 snowmobile noise levels
while
ranged between 77 and 86 dB(A) at 50 feet/ mini-bikes
produced between 75 and 80 dB(A). Outboard Marine Corp.
(Ref. 22) apparently has a snowmobile that can be as
quiet as 74 dB(A). It would appear that in the near
should
future off-highway vehicles be as quiet as on-
highway ones.
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Section 9.2.1 Measurement Distance
For the purpose of Section 9.2, the standard
measurement height shall be four (4) feet (1.2 meters), and
the standard horizontal measurement distance from the center-
line of the vehicle path shall be fifty (50) feet (15 meters).
Whenever it is not feasible to use fifty (50) feet, the distance
may be shortened to twenty-five (25) feet (7.4 meters), in which
case the values in Table 3 of Section 9.2 shall be increased by
6 dB(A).
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ARTICLE X BUILDING NOISE LEVELS
Discussion: At the present time we have no specific recom-
mendation on building codes for noise, even though such
codes are very much needed. They are a noise prevention tool,
in that all regulations must prevent design and construction
weaknesses that permit noise intrusion. Fixing up errors
after a problem is identified is generally impractical. How-
standards
ever, building code noise / have been slow in developing
and there is little evidence that those passed have been
enforced. a code provision of this type has strong
which is
impact on the powerful construction industry, - generally
against any form of additional constraints on its activity.
For a thorough discussion of building codes, the reader
should see Reference 32.
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ARTICLE XI LAND USE
General Discussion: Land use control is an important and
developing area for municipalities to use in reducing many
undesirable environmental impacts, including noise. This
article is intended as a noise prevention tool; the previous
articles have been corrective tools. The importance of pro-
visions such as that given below is that they give authority
which is not implied in the other articles. A simple example
should help.
A tract of land is to be zoned Residential for the purpose
of constructing single family homes. There is an industrial
activity contiguous to this tract of land which emits noise
that is just below the industrial limits set forth in Article
VIII. If the residential area is built, numerous complaints
will arise, and since Article VIII can only be enforced against
the noise maker, the industrial activity will now have to meet
residential noise limits. The fairness, and perhaps the legality,
of such procedures is open to question. Incorporation of this
article into a noise ordinance, requires community officials to
consider noise criteria and will give them a sound basis for deny-
ing permission to build next to a noisy activity. In the example
given, the industry could eventually be brought into compliance so
residential development need not be prevented for the long time.
If the noise source were an airport or freeway, the community
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would not have control of the source and this article would be
invaluable in preventing serious noise problems. Noise complaints
about major roadways are continually being received by EPO's of
communities which do not have land use provisions. They are unable
to respond to these complaints, which tends to discredit the
entire noise control program.
The major purpose of the provisions given below are to pro-
vide specific guidance during the review process for new projects
under control of the municipal government. Because few communities
have enacted provisions as comprehensive as those given below, there
is little enforcement experience on which to base preferred ordinance
provisions. Study has indicated that there may be two basically
different methods of controlling land use with respect to noise.
So, unlike previous provisions, we present all of the provisions
of Alternative 1 first, and then all the provisions of Alternative 2
next. There is some opportunity to synthesize some provisions of
Alternative 1 with those of Alternative 2.
Section 11.1 Noise Impacted Land Use.
ALTERNATIVE 1
No new construction shall be approved If the exterior
Day-Night Sound Level is in excess of those in Table 1 on a week-
day at any point on the proposed site for single family residential
use and at any point of proposed structures for other uses in which
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habitation is to occur. For multi-story buildings, the sound level
measurement shall be made at the appropriate heights for those
buildings. The burden of any necessary measurements shall be upon
the developer of the construction.
TABLE 1
MAXIMUM SOUND LEVEL
Airport Environs
Proposed Use L. NEF
Single Family Residential A G
Multi-family Residential B H
Institutions C I
Commercial D J
Industrial E K
Recreational Areas F L
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Discussion: The restriction of construction
in noisy areas is the most important tool to prevent
serious noise impact. The major sources of noise are
arterial roads and freeways and airports. There are
several recommended criteria for residential siting.
Ref. 48 recommends that 56 dB(A) not be exceeded more
than 10 percent of the time (1^= 56 dB(A).The Federal
Highway Administration (Ref. 31) recommends that 70 dB(A)
not be exceeded more than 10 percent of the time (L^q = 70dB(A).
The Deoartment of Housing and Urban Development
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(Ref. 49) will normally consider funding
provided that
assistance for residential units/ the 24 hour average sound
level does not exceed 65 dB(A) more than 33 percent of the
time (L33 = 65dB(A).
The U.S. Environmental Protection Agency (Ref. 6) has
Average
issued a document which uses the Day-Night/Noise Level, L, , as
an
the criterion for chronic noise exposure. That document has set
goals to be achieved which will protect the health and welfare of
our citizens with an adequate margin of safety. The levels set
forth as they relate to Table 1 above are: A = 55, C = 55,
D - 70, E = 70, F = 70.
As you might note at this point, no agency has adopted the
levels
same means to measure environmental noise/ A comparison
of the various measures suggests the recommendations may vary by
10 dB. We recommend that be used, because of the simplicity
of its measurement and the long-term averaging involved. The measure
does not adequately address acute noise intrusions, but it appears
to be the best one-number criterion available.
With regard to airport noise, the Noise Exposure Forecast
sometimes
(NEF) and Composite Noise Rating (CNR) are/ available
from the local airport for use by the community. The levels
identified in Ref. 6 and compared with airport noise criteria
in Ref. 50 suggest that NEF-20 or CNR-90 should be used for
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levels G, H, and I, respectively. In present planning around
airports, NEF-30 and CNR-100 are used and Ref. 49 uses these
latter numbers as a basis for funding support. These higher
levels may be used for G, K, and L.
Section 11.2 Commerical or Industrial Land Use.
No new commercial or industrial con-
struction shall be approved unless it
can be shown that the construction
will meet the provisions of Article VIII
of this ordinance for land use categories
existing at the time of construction.
Discussion: In almost all cases, these land use categories
result in noise generation. The provision implies a review
process within the municipality to insure the ordinance will be
met. Note that approval is based on existing conditions only.
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Section 11.3 Road Construction
No new road construction or modifications to existing roads
will be approved, whether locally funded or not, for residential
areas, unless any necessary noise control measures are taken to
insure that the Day-Night Noise Level due to all the vehicles
operating on the completed roadway does not exceed (x) dB at any
point around any residence on a week-day.
Discussion: This provision is for the purpose of insuring project
review before any new roads are built or old ones modified and for
the purpose of preventing noise impact if it is built. One large
source of problems for an EPO is complaints about highway noise,
which he is powerless to cure. This provision allows him to
prevent the problem
Section 11.4 Road Building
No new road construction or modifications to existing roads
will be approved unless the construction operations are in compliance
with the provisions of this ordinance.
Discussion; This provision requires the road construction itself
to be reviewed for compliance and to meet the ordinance. Normally
this operation would be conducted by a contractor to a governmental
agency and thus be exempt from the ordinance. The noise from road
building can have ten percentile levels in excess of 80 dB(A) at
the right-of-way boundaries if not properly controlled (Ref. 51).
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Section 11.5 Zoning Changes
No zoning change, adjustment, variance, or
exception, which affects the land use categories,
will be permitted unless the use to be allowed does
not violate the provisions of this ordinance.
Discussion: This provision requires review of
the noise impact of zoning changes and requires compliance
with this ordinance to be accomplished prior to the change.
Section 11.6 Truth in Selling or Renting
No person shall sell or rent, or cause to
be sold or rented, any structure to be used for
habitation, outside of which structure
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the sound levels are
in excess of those permitted
under this ordinance, without
making full disclosure to all
potential buyers or renters of
the existence of such noise
disturbance.
(Def. 18, 30 required)
Discussion: In many areas there are existing noise problems that
by municipalities, .
cannot be corrected/ e.g., homes near freeways and airports. This
provision is to insure that the future habitants will be perfectly
aware that a noise problem exists. It is beneficial in two ways:
(1) it permits noise sensitive people to avoid such areas, and (2) it
relieves the EPO of complaints over which he may have no control. The
Federal Interstate Land Sales Act (Public Law 91-152) has similar
provisions to prevent land sales frauds. That Act makes it unlawful
to use any device to defraud and allows a purchaser to revoke a con-
tract if a complete property report is not given in advance of such
contract. One of the requirements for the report is a statement of
"the existence of any unusual conditions related to noise or safety ...".
Freeways and airports would be in this category definitely. Whether
other sources of noise impact, such as a motor raceway, would be re-
quired for inclusion is still open to question. The Act only applies
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to interstate transactions, and this provision would make the same
concept apply at a community level. To make such a provision en-
forceable, it would be necessary to define noise-impacted zones in
the community and publish the information to the proper parties.
This task is simpler than it seems, and it may already have been done
if the recommendations of Chapter 2 have been followed. The number
of complaints an EPO receives about freeways and airports is quite
large in the bigger communities. We understand that Virginia Beach,
Virginia has a provision similar to that above.
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ALTERNATIVE 2
Section 11.1 Identification of High Noise Areas
For the purposes of this article, noise exposure levels
and contours identified for airports or highways pursuant to
guidelines or recommended practices established by the Federal
Aviation Administration, the Federal Highway Administration, or
the United States Environmental Protection Agency, as contained
in any report or environmental impact statement prepared by or
for said agencies, shall constitute prima facia evidence of the
noise exposures which are, or are projected to be, created by
such airports or highways.
Section 11.2 Site Study Requirement
(a) when, in the opinion of the (Noise Office/Noise Officer)
there is reason to believe that any proposed development of a type
regulated pursuant to section 11.3 is proposed to be located in an
area which is, or is projected to be, subject to a day-night average
no.is a J eve.I in excess of L, dB(A), prior to approval of any sub-
division, zoning, or building permit application, the applicant
shall be required to submit a noise study of the site in question.
Such study shall contain without limitation the following:
(1) A report of day-night average noise levels for
a representative sample of locations on said site,
conducted in accordance with the guidelines and pro-
cedures adopted by the (Noise Office/Noise Officer).
(2) A report of projected or proposed new or expanded
noise sources which may affect the noise exposure of the
site during the lifetime of the development, and the
projected future noise levels at the site resulting
from said new or expanded noise sources.
(b) In determining whether an applicant should be required
to submit a noise study pursuant to subsection (a) of this section,
the (Noise Office/Officer) shall consider any report recognized
pursuant to section 11.1 and shall, without limi.tation, consider
the criteria contained in the Noise Assessment Guide!ines developed
and published by the United States Department of Housing and Urban
Development.
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Section 11.3 Use Restrictions in High Noise Areas
(a) No new construction or development of single
family residences which shall be approved in any
area, or for any site, which is, or is projected
during the useful life of the structure to be,
subject to an exterior day-night average noise
level in excess of L2 dB(A).
(b) No new construction or development of
multiple-family residences, dormitories, mobile
homes, transient lodging, schools, hospitals,
nursing homes, or churches shall be approved in
any area, or for any site, which is, or is pro-
jected during the useful life of the structure
to be, subject to an exterior day-night average
noise level in excess of L^ dB(A) unless there
shall be incorporated into said construction or
development such noise insulation techniques as
are necessary and adequate to reduce the interior
day-night average noise level in such structure to
L^ dB(A) or less. Prior to issuance of the sub-
division, zoning, and building permit approval, the
Noise Office/Officers shall review and approve the
proposed noise insulation techniques to be in-
corporated into said construction or development.
Section 11.4 Field Testing
(a) Prior to issuance of any occupancy permit for
any construction or development regulated pursuant
to subsection (b) of section 11.3, the owner of
the structure shall submit, and the Noise Office/
Officer shall approve, the report of an independent
testing agency approved by the Noise Office/Officer,
certifying that noise insulation techniques have been
properly incorporated into the structure as approved
pursuant to section 11.3. Such report shall contain
a report of measurements of the exterior to interior
noise reduction of the structure for a representative
sample of locations within the structure. The noise
reduction for each location shall not be less than
that required to meet the standards of section 11.3 (b).
(b) The Noise Office/Officer is authorized to conduct
such tests and inspections of structures as are necessary
to assure the accuracy of any report submitted pursuant
to subsection (a) of this section emd to ascertain compliance
with the standards of section 11.3.
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Section 11.5 Equivalent Measurement Systems
For the purposes of this article, measurements and
designations of noise exposures shall be expressed in
day-night average noise level (L^n), or in equivalent
values expressed in noise exposure forecast (NEF),
composite noi^e rating (CNR) or any other equivalent
noise exposure measurement system approved by the
Noise Office/Officer.
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ARTICLE XII ADDITIONAL PROVISIONS
Section 12.1 Penalties
(a) Whenever in any section of this ordinance or any
rule or regulation promulgated hereunder, the doing of
any act is required, prohibited, or declared to be un-
lawful and no definite fine or penalty is provided for
a violation thereof. Any person, firm, or corporation who
shall be found guilty of violating any provision of this
ordinance shall, for each offense, be fined in a sum of not
more than dollars. (Every day of violation shall be
considered a separate offense).
(b) Any person who shall be found guilty of violating
any provision of this ordinance for a (second) (third) time
within a period, shall, for each offense, be fined
a sum of not less than and not more than or
imprisoned for a period not to exceed days, or both.
Discussion: The penalty provisions of noise ordinances are
important and highly variable but are subject to local con-
ditions, thus the above provision is only a sample. Section (a)
does not mention imprisonment and, thus the violation becomes
only a quasi-criminal offense which can be handled more easily.
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Section (b) makes further violations a criminal offense by
providinp for imprisonment, at this point full criminal
action comes into play. New York City CRef. 3) has a very
extensive section on penalties. Chicago (Ref. 15) considers
each day of violation as a separate offense. Salt Lake City
(Ref. 21), San Francisco (Ref. 14), and San Dieao (Ref. 2)
have reasonably simple provisions that are worth reviewinq.
Section 12.2 Additional Remedy-Injunction
ALTERNATIVE 1
The operation or maintenance of any noise
source in violation of any provision of this
ordinance shall be deemed and is declared to be
a public nuisance and may be subject to abatement
summarily by a restraining order or injunction
issued by a court of competent jurisdiction, or
in any other manner available for the abatement
of public nuisances.
ALTERNATIVE 2
(al Except as provided in subsection (b) ,
in lieu of issuing a notice of violation, the EPO/NCO
or other (agency/official) responsible for enforcement
of any provision of this ordinance may issue an order
requiring abatement of a sound source alleged to be in
violation, within a reasonable time period and according
to guidelines [to be approved by appropriate authorityj
which the EPO/NCO may prescribe.
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(b) An abatement order shall not be issued:
(11 for any violation covered by Section 12.1(b);
(2) for any violation of / or, (3)
when the EPO/NCO or other enforcement (agency)
(official) has reason to believe that there will not
be compliance with an abatement order.
Discussion: The use of a restraining order and
injunction is common in noise ordinances. The wording is
highly variable, although the provision above is typical
of many. You should look at the noise ordinances of other
communities (Refs. 2, 44, 21) and the provisions of other
types of ordinances in your own community so your proDOsal
to the City Attorney will be consistent with these other
local ordinances.
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You must check with the laws of the state to
determine whether a municipality may declare a violation
of an ordinance to be a nuisance £er sti. If such declaration
is allowed, this declaration may assist in enforcement
actions by invoking remedies available to public agencies
to abate nuisances under common and statutory nuisance.
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Section 12.4 Contracts:
Any written agreement, purchase order, or
instrument whereby the city is committed to the expenditure
of funds in return for work, labor, services, supplies,
equipment, materials, or any combination of the foregoing,
shall not be entered into unless such agreement, purchase
order, or instrument contains provisions requiring that any
equipment or activities which are subject to the provisions
of this code will be operated, constructed, conducted, or
manufactured without causing violation of the code.
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Discussion: This provision is closely modeled after that
for New York City (Ref. 3). San Diego (Ref. 2, Sec. 59.5.0301)
has a section on contracts, but specifically exempts the city
government or any local state or Federal agencies with whom
they have contracts. With this exception, the remainder of
the San Diego provision is worth reviewing. It is recommended
that, in the interest of simplicity, the above provision be used.
There are a number of municipality-related operations
which can cause severe noise impact: street repair, chain sawing,
log chipping, garbage collection, and so forth. Technologically,
most of these sources can be controlled to be in compliance with
Article VI or VIII. Article IV requires city agencies to comply
with the ordinance and this provision requires contractors to do
so also.
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Section 12.5 Low Noise Emission Products
Any product which has been certified by
the Administrator of the U.S. Environmental Protection
Agency pursuant to Section 15 of the Noise Control Act
of 1972 as a low noise emission product and which he
determines is suitable for use as a substitute, shall
be used in preference to any other product, provided
that such certified product has a procurement cost which
is not more than 125 percentum of the least expensive
type of product for which it is certified as a substitute.
Discussion: The enactment of the Noise Control Act of 1972 has
provided communities an opportunity to buy quiet products as
soon as the certification procedure described in the provision
above is activated. This section will provide specific guidance
to other agencies of the municipality that are required by Article
IV to comply with the provisions of this ordinance.
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Section 12,6 Method of Enforcement.
Violation of this ordinance shall be cause
for summons and complaint to be issued forthwith; provided,
however, that if the noise source is not a motor vehicle
moving on a public right-of-way, in lieu of a summons and
complaint, enforcement personnel may issue a 24-hour notice,
or other reasonable amount of time not to exceed (x) days,
signed by the (Environmental Protection Officer), in writing,
which may be served personally or by certified mail to the
last known address of the person to whom addressed, with
return receipt requested, directed to the owner, occupant,
person or persons in charge of or in control of the device,
building, or premises to abate said violation of this ordinance.
Failure to comply with the order so issued and served shall
constitute a violation of this ordinance.
(Def. 14, 24 required).
Discussion: This provision gives permission to the enforcing
officer not to issue summons on all cases. Experience (Refs. 13,
35) has shown that the "soft fuzz" approach keeps citizen support
for ordinance enforcement, as well as solving the problem. Boulder
(Ref. 35) also recommends dismissal of the mandatory summons for
moving violations if the vehicle is brought into compliance prior
to the court date.
NIMLO (Ref. 1) recommends a provision similar to the one
above. Lakewood (Ref. 4) has a nearly identical provision. Larger
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cities have more detailed provisions. If the method of
enforcement can be left to rule making as provided for,
say, in Section 5.2, the ordinance will be simpler.
Section 12.4 Other Remedies
(a) Any remedy available pursuant to this ordinance
shall be considered separate and not exclusive of any other
remedy available hereunder.
(b) Nothing in this ordinance shall be construed to
impair any cause of action, or legal remedy therefore, of
any person or the public for injury or damage arising from
any violation of this ordinance.
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ARTICLE XIII Severability
It is hereby declared to be the intention of
the City Council that if articles, sections, paragraphs,
sentences, paragraphs, sentences, clauses, and phrases of this
ordinance shall be declared unconstitutional or invalid by the
valid judgment or decree of any court of competent jurisdiction,
such unconstitutionality or invalidity shall not affect any
of the remaining articles, sections, paragraphs, sentences,
clauses, and phrases of this ordinance.
Discussion: The above provision is a synthesis of several
severability clauses found in effective noise ordinances and may
have more words than you wish to include. Since noise ordinances
are relatively new, a severability clause may very well be necessary
in case future litigation strikes down some portion of the ordinance.
Most comprehensive ordinances contain such a clause. NIMLO (Ref. 1)
recommends the clause; Lakewood (Ref. 4), Boston (Ref. 8), and Baltimore
(Ref. 7) have such provisions.
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2
3
4
5
6
7
8
9
10
11
12
13
14
7.178
REFERENCES FOR CHAPTER 5
Model Noise Ordinance. National Institute of Municipal
Law Officers, (no date)
Ordinance No. 11122, amending Chap. V, Art.6 of San Diego (Calif.)
Municipal Code, (1973)
Local Law No. 57, Noise Control Code, City of New York (N.Y.),
(1972)
Ordinance Repealing and Reenacting Chapter 9.52 of the
Lakewood (Colo.) Municipal Code, (1973)
Inglewood (Calif.) Municipal Code, Chapter 6 - Noise
Regulation (1970)
Levels of Environmental Noise for the Protection of Health
and Welfare" U.S. EPA document (1974)
Ordinance No. 108 to repeal certain sections of Article 19 of
Baltimore (Md.) City Code and add new sections on noise
control (1973)
Regulations for the Control of Noise in the City of Boston (Mass.)
City of Boston Air Pollution Control Commission (1973)
Suggested State Noise Control Legislation, Council of State
Governments Document (1973)
Bragdon, Clifford, Municipal Noise Ordinances, Sound and Vibration
Magazine, 16-22 (Dec 1973)
Yoder, Galen 0. Land Use Planning for Noise Control. Internal
Document, U.S. EPA/Region VIII (1973)
Chanaud, R. Noise in Boulder, Colorado, 1972, Engineering Dynamics
Report (1973)
Simnons, Robert A. and Chanaud, Robert C., Community Noise Control
Activity in the Rocky Mountain-Prairie States. Proc. Noisexpo,
Chicago, 111. Sept. 11-13, 1973
Ordinance 274-72 Amending Part II, Chap VIII, San Francisco (Calif.)
Municipal Code by adding Article 29 (1972)
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7-179
15. Noise Ordinance amending Chap, 17 of Municipal Code of Chicago,
111. (1971)
16. Baron, R.A. "The Tyranny of Noise" Harper & Row, New York (1970)
17. Noise from Construction Equipment and Operations, Building Equipment,
and Home Appliances. U.S. EPA document NTID 300.1 (1971)
18. Public Law 92-574, Noise Control Act of 1972, administered by the
U.S. EPA
19. Pugh vs.Edison Electric,Boulder District Court, Boulder, Colo. (1973)
20. Public Health and Welfare Criteria for Noise. U.S. EPA Report
550/9-73-002, (1973)
21. Ordinances amending Title 32 and Section 291, Article 23 of the
revised ordinances of Salt Lake City, Utah (1971)
22. Noise Control Report April 17, 1972
23. Noise Source Regulation in State and Local Noise Ordinances
U.S. Environmental Protection Agency NTID 73.1 (1973)
24. Proposed Regulation for the Prevention and Control of Environmental
Noise Pollution, Subchapter C, Title 6, Chapter 4. Official
Compilation of Rules and Regulations, State of New York (1972)
25. Noise Regulations, Chapter 8 of Illinois Pollution Control Board
Rules and Regulations (1973)
26. The Standard Land Use Coding Manual, U.S. Government Printing
Office (1969)
27. Hawthorne (Calif.) Municipal Code, Sections 12-1100, 12-1200, and
12-1300
28. Botsford, J.H. "Using Sound Levels to Gauge Human Response to
Noise." Sound and Vibration Magazine, 3, 16-28 (Oct 1969)
29. Anon. "Control of Noise from Stationary Sources Report of the
Task Force on Noise, Institute of Environmental Quality,
State of Illinois (Jan 1972)
30. Anon. Community Noise Measurements in Los Angeles, Detroit, and
Boston, Bolt Beranek and Newman Report 2078,(June 197l)
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31.
32.
33,
34
35
36
37
38
39
40
41
42
43
7-1RO
Policy and Procedures Memorandum 9(1-? U.S. Federal
Highway Administration (1973)
Weston, R.T. "A Model Ordinance to Control Noise through
Building Code Performance Standards," Harvard Journal
on Legislation, jj, 66-114, (1973)
Anon. "Background Document to Proposed Interstate Motor
Carrier Regulations" Fed. Reg. 38, No. 144, Part 1 or
EPA Document 550/9-73-005 (Nov 1973)
Ordinance No. 3554 amending Chapter 21 of the Revised Code
of the City of Boulder (Colo.) (1970)
Adams, J., Simmons, R.j.and Chanaud, R. "Experience with
Noise Enforcement in Boulder, Colorado." Lecture
before Acoustical Societv of America Meeting,
Los Angeles, Calif. (Nov.1973)
Passenger Car Noise Survey, Dept. of the California
Highway Patrol, (Jan. 1970)
Hillquist, R.K. and Scott, W.N. Motor Vehicle Noise
Spectra, their Characteristics and Dependence upon
Operating Parameters" Jo. of
the Acoustical Society of America, 5J[, 2-10 (1975)
Anon. Noise Measurements of Motorcycles and Trucks,
Bolt, Beranek and Newman Report 2079 (June 1971)
Article 10, Subchapter 4, Chap. 2, Title 13, California
Administrative Code
Section 23130 California Vehicle Code
Ranck, Richard, Salt Lake City Noise Control Officer,
private communication,
Sharp, B. H., Research on Highway Noise Measurement Sites,
Wyle Laboratories Research Staff Report WCR 72-1 (1972)
State of Hawaii, Vehicular Noise Control for Oahu, Chapter 44A,
Public Health Regulations
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7-IB]
44. Ordinance amending Article 5, Chap. 151, Title IX, Code of
the City of Grand Rapids (Mich.) (1973)
45. English, J.W. Laws Regulating Off-Highway Vehicles,
Traffic Laws Commentary, 1 No. 8, (Dec 1972) published
by U.S. Dept. of Trans., "flat. Highway Traffic Safety
Administration
46. Anon. Manual of Recommended Standards and Engineering Practices
for Snowmobiles, International Snowmobile Industry Assoc.
pamphlet (1973)
47. Transportation Noise and Noise from Equipment Powered by
Internal Combustion Engines
U.S. Environmental Protection Agency Document NTID 301.13
(1971)
48. National Cooperative Highway Research-Program Report 117
49. Departmental Circular 1390.2, U.S. Dept. of Housing and Urban
Development (1971)
50. Report on Aircraft-Airport Noise. Report of the Administrator
of the U.S. EPA to the Committee on Public Works, U.S. Senate,
Serial No. 93-8. U.S. Government Printing Office, Washington,
D.C. (1973)
51. Construction Site Noise Survey, New York State Dept. of
Environmental Conservation Report, April 1974.
52. Chapter 9.10 of the Palo Alto (Calif.) Municipal Code (1972)
53. Anon. Report to the President and Congress on Noise U.S. Senate
Document 92-63 (February 1972)
54. Amendment to Denver Colo. Municipal Code to add Article 717 (1974)
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