EPA
SJSnSn". Paction	SSSaL.™. .rrf Con,ro. EPA REPORT NO- 550/9-82-105
Agency	Washington, DC 20460	Ap3Tll ±932
Noise
GUIDELINES FOR NOISE IMPACT ANALYSIS

-------
TECHNICAL REPORT OATA
(Mease rrod tumui-turns t m the rrreru brjorr com/'fcifiixl
. *6?OHTNO, 2.
¦ 550/9-82-105
'liiriwrflT3-
•• TITI»S ANO SUBTITLE
Guidelines for Ifoise Impact Analysis
5. REPORT OATf
April 1982
>. PERFORMING ORGANIZATION COOt
EPA/CNAC
. AUTHOR!*)
8. PERFORMING ORGANIZATION REPORT NO.
550/9-82-105
. PERFORMING ORGANIZATION NAM! ANO AOORESS
Office of Noise Abatment and Control
U.S. Environmental Protection Agency
401 M St. S.W.
Washington, D.C. 2Q460
10. PROGRAM ELEMENT NO,
11. cdNTR ACT/BRANT NO.
•
2. SPONSORING AGENCY NAME ANO AOORESS
(Eeport #9)
13, TYPf OP REPORT AND PtRlOO COViRiO
14. SPONSORING AGENCY CODE
EPA/CHAC
i. SUPPLEMENTARY NOTES
L ABSTRACT . 		 	
The purpose of the guidelines proposed in this report is to provide decision-
makers, in both the public and private sectors, with analytic procedures which can
be uniformly used to express and quantify isfsacts from noise, so that such impacts
can be readily understood and fully considered within the comparative equations
which constitute noise environment decisions. The procedures contained within the
guidelines are applicable to the preparation of environmental noise assessments,
and environmental inspect description of noise environrnent changes would be useful.
The procedures allow a user to arrive at an objective, and for most situations,
quantitative definition of noise impact, in many situations, the procedures
will allow the calculation of a single number descriptor which expresses the total
' noise impact of a proposed project on the population exposer. -
-The quantification methods reccraaended for intact assessment in these
guidelines are further developments of the Fractional Impact Methodology used
fee assessing the health and welfare effects of a noise environment. Three
principal types of noise and vibration environments are considered; general
audible noise; special noises; and vibrations. There is a separate chapter for
each of these principal types of environment.
K*Y WORCS ANC DOCUMENT ANALYSIS
DESCRIPTORS
&.10ENT1PIERS/OP5N ENOEO TERMS
e. cosati Field/Group
Itoise Impact Noise Effects
Noise Criticisri Noise Assessment .
General Audible Sbise
High-Energy Bsgulse Noise
Infrasound
Ultrasound
Vibration
Noise

aisTsisuTioN statement
EPA mailing list NT1S
IS. SECURITY CLASS iTita Report)
Unclassified
21. NO. Qr f1 AQCS
214
20. SECURITY CLASS 1 Thit pagr/
Unclassified
32. PRICE j
Werri 2223-1 (3-?:i
I

-------
\
EPA REPORT NO. 550/9-82-105
April 1982
(13 f T HU'I TMPC PAD \Y\TCrS* TMD'h.r^V amTVCTC
This recort has been approved for general availability. The contents of
this resort reflect the views of the contractor, who is responsible for the
facts and the accuracy of the data presented herein. This resort does not
necessarily reflect the official views or policy of EPA. This report does
not constitute a standard, specification, or regulation.
PERMISSION IS GRANTED TO REP1DDCCE THTS MaTHSIAL WITHOUT FURTHER C-SkBANCE

-------
FOREWORD
The purpose of the guidelines proposed in. this report is to provide
decision-makers, in both the public and private sectors, with analytic proce-
dures which can be uniformly used to express and quantify impacts from noise,-
so that such impacts can be readily understood and fully considered within the
comparative evaluations which constitute noise environment decisions. The
procedures contained within the guidelines are applicable to the preparation
of environmental noise assessments. Adherence to the procedures within the
guidelines is strictly voluntary. The guidelines are neither mandatory nor
regulatory in intent. Specific numbers which appear in the guidelines should
not be construed as standards, nor are they intended to supplant any locally
established community noise level limits or decisions on environmental ac-
ceptability with respect to noise as fostered by certain states, municipali-
ties, or other governmental jurisdictions. Instead, the guidelines are
offered here as simply a tool to allow decision-makers to consider trade-offs
between environmental benefits and costs anew for potentially noisy projects.
The guidelines are based on the deliberations of the Committee on Hear-
ing, Bioacoustics and Biomechanics (CHABA) Working Group 69, National Academy
of Sciences (NAS), from 1972 to 1976, in response to a request in 1972 by
the U.S. Environmental Protection Agency (EPA). In early 1977, recommended
procedures were published by the National Academy of Sciences in a document
entitled "Guidelines for Preparing Environmental Impact Statements on Noise."
That document provided a comprehensive set of procedures for specifying the
physical descriptions of environmental noise and vibration, and methods for
assessing the degree of Impact on people associated with these environments.
The technical approaches proposed by NAS underwent several significant
changes during the period of CHABA working group activity as a result of
i(bl

-------
working group deliberations, public discussions, and presentations at national
and international technical meetings. Under the constraint that the proce-
dures contained within the guidelines must reflect a compromise among factors
of practicality, economy, desired accuracy, and specificity, the working group
tried to be responsive to the numerous suggestions received from government
agencies, industries, and the scientific community. The proposed procedures
were tried out by several of the working group members and others, and short-
comings and gaps were identified. This led to joint working group research
activities or to efforts by individual members. Many of these individual
efforts, which had their roots in the working group activities, were conducted
and sponsored under other government or private industry programs and have
been separately published in the meantime. Similarly, some agencies, faced
with the need for operational decisions, used concepts from the proposed
guidelines in their publications; those publications are included among the
references cited in the guidelines. Some of the proposed methods contained
within the guidelines have been officially adopted by several agencies.
Further, close liaison was maintained between the working group and several
writing groups working on related items under the American National Standards
Institute (MSI) Acoustical Standards Committees. In summary, the working
group tried to be responsive to all potential users concerned and tried to
reach consensus wherever possible.
During the summer of 1977 , EPA distributed copies of the NAS report to
Federal agencies and other interested parties with a request for comments.
On June 30. 1978, a request for further comments was published in the Federal
Register (43 FR 28549). Both of these actions were taken to provide an oppor-
tunity for additional viewpoints and expertise to be considered in a proposed

-------
revision of the NAS report. EPA then carried out s detailed, step-by-step
analysis of the issues raised during the comment period in order to improve
the overall accuracy, usage, and general readability of the document.
Conceptually, the latest draft version of the guidelines contains the
same basic procedures delineated in the NAS guidelines published in 1977.
However, because of some refinements in the assessment methodologies, IFA in
February 1981, extended to the original commenters an opportunity to comment
on the final draft version. At the same time, other Federal agencies were
informed as to the existence of the revised draft, and were afforded an
opportunity to comment. Comments were also solicited from the National
Academy of Sciences, and from other individuals and organizations who speci-
fically requested an opportunity to review the draft revision to the guide-
lines. Accordingly, revisions have been made to the 1981 draft report to
reflect the additional comments received.
Finally, it is only fair to say that in a report as comprehensive and
exploratory as this one, not all working group members agreed with all the
details in the report. However, they all agreed with its essential concepts
and the general approaches, and hoped that the details would be worked out,
corrected, and fall in place as experience with the proposed guidelines is
gained. Similarly, not all of those commenting on the report will be satis-
fied with the revisions which have been made. In the face of continued gaps
in knowledge, honest differences of opinion will undoubtedly remain about the
procedures recommended in this publication. Nevertheless, it was important
for these guidelines to be published as soon as possible in order to assist
in providing guidance for uniform methods of noise impact assessment. It
should be recognized that it may be necessary to update these guidelines in
iii

-------
the future. The guidelines are open to revision as new information becomes
available.
These revised guidelines were prepared under the guidance of the Office
of Noise Abatement and Control, U.S. Environmental Protection Agency. EPA
wishes in turn to acknowledge the contributions of the members of Working
Group 69 of CHAM to the development of these recommended guidelines, We also
wish to thank the members of CHABA Working Group 84 for their assistance in
the development of the method for assessing human response to high-energy
impulse noise. We extend further thanks to all the commentors who provided us
with most helpful comments which led to the revision of the guidelines, and
who demonstrated noble patience and forbearance during the lengthy revision
process. Finally, we wish to express our sincere appreciation to Frederick L.
Hall of McMaater University who assisted us in analyzing the comments and
drafting the revision, and whose insights and suggestions proved invaluable
to the final issuance of these guidelines.

-------
Committee on Hearing, Bioacoustics, and Biomechanics
Working Group 69
on
Evaluation of Environmental Impact of Noise
Henning E, Von Gierke, Chairman
Wright-Patterson AFB
Clifford Bragdon
Georgia Institute of Technology
Kenneth Eldred
Ken Eldred Engineering
William J. Galloway
Bolt Beranek and Newman, Inc.
Jeffrey Goldstein
Environmental Protection Agency
Ira Hirsh
Central Institute for the Deaf
David H. Mudarri
Environmental Protection Agency
John Reed
Sandia Laboratories
Paul D. Schomer
Construction Engineering Laboratory
Theodore Schultz
Bolt Beranek and Newman, Inc.
Simone Yaniv
National Bureau of Standards
Daniel L. Johnson
Wright-Patterson AFB
Robert Young
San Diego, CA
Working Group 84
on
Human Response to Impulse Noise
William J. Galloway, Chairman
Bolt Beranek and Newman, Inc.
Daniel L. Johnson	Paul D. Schomer
Wright-Patterson AFB	Construction Engineering Laboratory
Karl D. Kryter	Peter J. Westervelt
SRI International Inc.	Brown University
v

-------
CONTENTS
Section	Title	Page
1.	Introduction	1
1.1	Purpose of the guidelines	1
1.2	Overview of the approach	3
1.3	Structure of the guidelines	7
1.3.1	Preliminaries	8
1.3.2	General audible noise	12
1.3.3	Special noises	13
1.3.4	Vibration	14
1.3.5	Potential changes in population	14
1.3.6	Examples	15
1.4	Other considerations	16
1.4.1	Projects which reduce noise	16
1.4.2	Temporary projects	17
1.4.3	Uncertainties in the analysis	18
2.	General audible noise	19
2.1	Basic screening procedures	20
2.1.1	Measures for the decription of general
audible noise	23
2.1.2	Determining the yearly day-night sound level	25
2.1.3	Determining the population affected by the
noise of the proposed project	30
2.2	Health and welfare effects	33
2.2.1	Human noise exposure criteria	33
2.2.2	Quantification of the noise impact	41
2.3	Severe health effects	52
2.3.1	Human noise exposure criteria	54
2.3.2	Quantification of the impact	60
2.4	Environmental degradation	62
2.5	Treatment of temporary projects	64
2.6	Practical Example	66
3.	Special noises	71
3.1	High-energy impulse noise	71
3.1.1	Description of high-energy impulse noise	72
3.1.2	Human noise exposure effects of high-energy
impulse noise	75
3.1.3	Structural damage criteria for impulse noise	80
3.2	Infrasound	85
3.2.1	Description of infrasound	85
3.2.2	Human noise exposure effects of infrasound	85
3.3	Ultrasound	87
3.3.1	Description of ultrasound	87
3.3.2	Human effects of ultrasound	88
3.4	Noises with information content	88
4.	Vibration	89
4.1	Human effects of vibration	89
vi

-------
CONTENTS (Continued)
Section	Title	Page
4.1.1	Description of building vibration	90
4.1.2	Human vibration exposure criteria	90
4.1.3	Quantification of the impact	95
4.2 Structural effects of vibration	98
5. Summary of noise impact analysis	100
5.1	Purpose and structure of the guidelines	100
5.2	Analysis of impacts of general audible noise	101
5.3	Analysis of impacts due to special noises	104
5.4	Analysis of impacts due to vibration	105
References	1-1
Appendix A	Acoustical terms and symbols used in the guidelines,
and some mathematical formulations for them	A—1
B Environmental noise measures and procedures	B-l
1.	Environmental noise measures and their purposes
in Federal programs	B-2
2.	Estimating from other noise measures	B-3
C.	Summary of human effects of general audible noise	C-l
D.	Measurement of and criteria for human vibration
exposure	0-1
E.	Example application of guideline procedures for
general audible noise	E-l
vii

-------
1
2
3
4
5
6
7
8
9
10
11
12
LIST OF TABLES
Title	Page
Summary of methods for noise impact analysis	6
Yearly day-night sound level as estimated by
population density	29
Values of the weighting function for general
adverse response	47
Average hearing loss as a function of 8		hour	38
Criterion function for severe health effects	60
Sample data presentation: future noise levels
without proposed project	67
Sample data presentation: future noise levels of
project alone	68
Sample data presentation: future levels front all
sources combined	69
Sample data presentation: special situations	70
Values of weighting function for hig' energy
impulse noise	79
Conversion of L^q to L^n via equal annoyance	81
Basic threshold acceleration values for acceptable
vibration environments	92
viii

-------
LIST OF FIGURES
Figure Title	Page
1	Preparation of a noise impact	analysis 5
2	Flow chart and worksheet	9
3	Screening diagram	21
4	Summary of annoyance data from 12 surveys showing
close agreement	• 37
5	Comparison of new annoyance function with previous
functions	39
6	Suggested descriptors for various situations	50
7	Comparison of curvilinear function and fractional
impact linear function	53
8	Potential hearing damage risk for daily exposure to
8-hour equivalent sound levels	59
9	Recommended relationship for predicting community
response to high energy impulsive sounds	78
10	' Infrasound criteria	86
11	Weighting characteristic for building vibration
in terms of human responses for the frequency range
1 to 80 Hz	91
12	Vibration criteria for residential areas	94
13	Percentage of population complaining as a function
of peak acceleration	96
14	Types of analyses suggested	103
IX

-------
CHAPTER 1
INTRODUCTION
It xs the policy of the Unxted States Government to consider the poten™**
tial adverse impact on the environment of all proposed federal actions and
projects. Many states and local governments have similar policies. The
purpose of such policies is not merely to provide a catalog of the adverse
environmental impacts of a project (which may have already received tacit
approval). Rather, the purpose is to provide a description of the environ-
mental consequences of a possible project, so that an understanding of those
consequences can be an integral part of the decision on the project. In order
for this to occur, it is necessary for the environmental effects to be ex-
pressed in a manner which can be readily understood by the decision-maker,
and by the general public whose participation in such decisions is usually
encouraged by all levels of government.
1•1 Purpose of the guidelines
One of the potential environmental consequences of many proposed actions
or projects is a change in the noise and vibration environment. The "action"
may be the building of a new refinery, development of a new mine, construction
of a road, use of a new piece of machinery, etc. It may involve the enlarge-
ment or the reduction in size of an existing facility, or an effort to make a
given facility quieter. It may be the promulgation and enforcement of a new
noise abatement regulation. It may be the temporary noisy construction phase
of an inherently quiet facility. Or, with no change in the noise environment,
the action may entail a change in land use or population density in a neigh-
borhood. Any proposed change that will significantly affect either (a) the
amount of noise generated or (b) the number of people exposed to it, will
1

-------
result in noise-related environmental impacts. These guidelines contain
procedures which can be used to describe and quantify those noise related
impacts. These procedures are primarily intended for use during initial
planning stages of projects in order that the potential environmental noise
effects of proposed actions can be identified and considered early in the
decision process, and so that appropriate noise mitigation measures can be
conveniently implemented.
The users of this document are expected to be federal agencies, state
and local governmental agencies, industries, environmental groups, and indi-
viduals. The procedures described here are applicable to the preparation
of environmental assessments and environmental impact statements, and to any
other situation in which a description of noise environment changes would be
useful. Although individual agencies have their own specific procedures, in
most instances the approach described here is consistent with those proce-
dures. These guidelines are not intended to replace existing approaches, but
to complement and extend them, by showing how to proceed from a description of
noise levels to a quantitative description of the impacts of noise on people.
It is hoped that this document will assist in achieving nationwide consistency
in dealing with noise problems, and provide an objective and uniform evalua-
tion of the noise impacts.
The approaches described in these guidelines are not mandatory, nor are
specific numbers which appear in the guidelines intended to be construed as
standards. The guidelines are offered as an aid to the treatment of noise
impacts in the preparation of environmental assessments, reviews, and impact
statements. Paraphrasing a statement by the Council on Environmental Quality,
these guidelines are intended to help public officials make decisions which
are based on an understanding of environmental consequences, and to take
2

-------
actions that protect, restore, and enhance the environment [1*, p. 25233],
The purpose of these guidelines, then, is to present procedures which can
be used to express noise impacts in terms which are easily understood by
decision-makers, so that those impacts can be fully incorporated in the
comparative evaluations which constitute the decision.
1,2 Overview of the approach
The guidelines are based on the philosophy that the technical approach,
the descriptors of the noise environment, the measurement and prediction
methods, the evaluation criteria, and the techniques for impact assessment
should be as simple as possible consistent with reasonable accuracy. To
the extent that they are also uniform across different projects, public
understanding of noise impacts will be improved.
It appears feasible to follow these principles to arrive at an objective,
and for most situations, quantitative definition of the noise impact. In many
situations, it will be possible to calculate a single number which expresses
the total noise impact of a proposed project on the population exposed. When
this single number index can be produced, the prospects are enhanced for a
more objective and rational comparison of noise with a host of other criteria
or impacts associated with specific projects. Quantitative tradeoff studies
are made possible—for example between noise impacts and societal benefits.
In some cases, this level of quantification might seem unwarranted, or overly
mechanistic. For such cases, the guidelines suggest a tabulation, in 5 deci-
bel (dB)** increments, of the land area or number of people affected by
~Numbers in square brackets refer to the reference list at the end of the
main text of this report.
^~Definitions of acoustical terms and symbols used in the guidelines are pro-
vided in Appendix A. In this report, decibels are always assumed to be
A-weighted unless designated otherwise.
3

-------
adverse noise levels. In addition, a traditional, non-quantitative descrip-
tion of the noise impact is encouraged, either as a supplement to these
numerical descriptions, or, in unusual cases, as the sole analysis of the
noise impacts.
The preparation of a noise impact analysis proceeds through several
distinct steps to arrive at these descriptions of the noise impact, which
are then used in the decision-making process (Figure 1). The methods pro-
posed for use in each of these steps (Table 1) are based, in part, on the
work and the progress achieved over the last few years by interagency com-
mittees, on the recommendations of the National Academy of Sciences-National
Research Council, and on other scientific findings.
For measurement of the noise environment, use of the A-weighted day-
night sound level (L^), officially adopted by several government agencies
(see Appendix B, Table Bl) since publication of the Environmental Protection
Agency's "Levels Document" 12], is recommended as the primary measure of
general audible noise.	has been recommended as an environmental noise
descriptor for purposes of land use compatibility planning by an interagency
task force on this subject [3], and by the American National Standards
Institute [4]. Circumstances calling for the use of short-term measures of
general audible noise are also discussed. A modification of the day-night
sound level for impulse noise is based on a report of a National Academy of
Sciences, Committee on Hearing, Bioacoustics and Biomechanics (CHABA) [5].
Measures to be used for infrasound, ultrasound, and vibration are also de-
scribed in these guidelines.
The quantification methods recommended for impact assessment in these
guidelines are further developments of the Fractional Impact Methodology used
by EFA for assessing the health and welfare effects of a noise environment.
4

-------
Description of Project or Action
Discussion and Analysis of Results
Decision on Proposed Project
Assessment of Impact
a.	Health and Welfare Effects
b.	Severe Health Effects
c.	Environmental Degradation
Look for Noise-Related Effects of Project or Action
Does Noise Environment Change?
Does Exposed Population Change?
Are Changes Significant Enough for Detailed Documentation?
Measurement and Documentation of Noise/Exposed Population
b.	Projection of Future Noise/Exposed Population
c.	Change in Noise/Impact of Project
Figure 1. PREPARATION OF A NOISE IMPACT ANALYSIS
5

-------
TABLE 1. SUMMARY OF METHODS FOR NOISE IMPACT ANALYSIS
TYPE OF	TYPE OF	RECOMMENDED	SCREENING	ASSESSMENT
ENVIRONMENT	CRITERIA	NOISE MEASURE	LEVELS	METHODOLOGY
GEN
AUD
NOIS
ERAL
IBLE
POTENTIAL FOR LOSS
OF HEARING
8 HOUR AVERAGE SOUND LEVEL OR
24-HOUR AVERAGE SOUND LEVEL
Ldn"76«®
HEARING-LOSS-WEIOHTEO
POPULATION. HWP

GENERAL ADVERSE
EFFECTS
DAY-NIGHT SOUND LEVEL
PROJECT LEVELS
HIGHER THAN
10 dB BELOW
THE EXISTING
LEVELS
SOUND-LEVEL-WEIGHTEO
POPULATION. LWP

ENVIRONMENTAL
DEGRADATION
TABLES AND DESCRIPTION ONLY
SPECIAL
NOISES
HIGH
ENERGY
IMPULSE
NOISE
STRUCTURAL
DAMAGE
PEAK PRESSURE
EMPIRICAL
FORMULAS
TABLES AND DESCRIPTION ONLY
PEAK ACCELERATION
1 m/Mc2 INSIDE
ANNOYANCE DUE TO
AUDITORY STIMULATION
AND BUILDING
VIBRATION
DAY NIGHT SOUND
LEVEL USING C WEIGHTED
SOUND EXPOSURE LEVEL. Lv. FOR
IMPULSES
1-Sc OF BOdB FOR
DAYTIME. OR 70 dt
FOR NIGHTTIME
SOUND-LEVEL-WEIGHTEO
POPULATION. LWP
INFRASOUND
ANNOYANCE AND
PHYSIOLOGICAL
MAX-
0.1 Hi TO 20 Hi 1 SOUND
O.VHz TO & Hz: 120 dB ,
5 Hi TO 20 Hi: 120-30 LOQ-p
DISCUSSION OF POSSIBLE EFFECTS.
NO TABULATION MADE
(iLTRASOUND
20 kHz to 100 kHz f PHfcSSURE
LEVEL
105 dB b
VIBRATION
STRUCTURAL
DAMAGE
PEAK ACCELERATION (WEIGHTED)
1 m/McZ FOR MOST
STRUCTURES
Of m/MC2 FOR SENSITIVE
STRUCTURES
0.0S m/Mc2 FOR CERTAIN
ANCIENT MONUMENTS
TABLES AND DESCRIPTIONS ONLY
ANNOYANCE AND
COMPLAINTS
RMS ACCELERATION (WEIGHTED)
VERSUS TIME OF EXPOSURE
0.0036 m/Mc2 OR
HIGHER DEPENDING ON
TIME OF DAY AND
TYPE OF PLACE
VIBRATION-WEIGHTED POPULATION.
VWP

-------
For the general adverse response to noise in the 55 to 75 dB (I^q) range,
the function is based on data presented by Schultz in a recent review paper
[6]. Similar impact assessment methods are proposed in these guidelines
for quantifying the following: the potential for loss of hearing at 24-hour
equivalent sound levels in excess of 70 decibels; the general adverse response
to impulse noise; and the complaints caused by vibration. For general audible
noise in rural and wilderness areas, and for infrasound and ultrasound,
qualitative rather than quantification methods are suggested.
The measures "and methods listed in Table 1 and described in this report
are simplifications, and the recommendation for their use is not intended to
discourage more rigorous approaches. However, to provide a common framework
for comparison of different environmental noise assessments (conducted by
different persons in different parts of the country), it is strongly recom-
mended that the methods of these guidelines also be used along with any other
additional approach.
1-3 Structure of the guidelines
Three principal types of noise and vibration environments are considered;
general audible noise; special noises; and vibration. General audible noise
is noise as commonly encountered in our everyday living environment. It can
be adequately described by either the equivalent A-weighted sound level (Le<^)
or its variation that includes a nighttime weighting, the day-night sound
level (L^n). For most practical cases this type of noise measure will ade-
quately describe the noise environment, and much of the document concerns the
evaluation of general audible noise. Not all noises can be adequately evalu-
ated by average sound levels, however. Examples of such special noises are
infrasound (frequency range of 0.1 to 20 Hz), ultrasound (frequency range
7

-------
above 20 kHz), certain types of impulse noises (such as blasts and sonic
booms), and sounds that convey more information than random noise sources
with comparable average sound levels (such as voices, warning signals, or
barking dogs). Procedures are also included for evaluating the impact of
vibration on man. While the main reason for their inclusion here is to
account for vibration generated by airborne noise, the impact of certain
types of vibration can be assessed whether the transmission paths are air-
borne or structureborne.
There is a separate chapter for each of the three principal types of
environment. Each chapter covers four topics: the appropriate physical
measurement for that type of noise; methods for determining the existing
levels and for predicting the levels for the proposed project; human noise
exposure criteria; and procedures for quantifying the impact, usually in
terms of those criteria. All of the information necessary to deal with
one type of noise environment is thus in one place, to minimize the effort
required by a user to follow these guidelines.
1.3.1 Preliminaries
The logic of the structure of these guidelines has been set out in a
combined flow chart and worksheet (Figure 2), to provide guidance for using
this report and for carrying out the various parts of the noise impact
analysis. There are four principal branches in the flow chart (labeled A, B,
C and D) to be followed, depending on the nature of the proposed project and
its potential impact. There are exit points along each of the branches, at
which the analysis for that branch may stop without the need for any further
analysis, since it is clear by then that there is no significant noise
impact with respect to the concern on that branch. At the right-hand edge of
8

-------
rMxcf oi,
mtiiuuimI
KKUnON
~o
TO
O
O
o
HOIt: HUMKM M PAttHTNISfS Ntffl 10 THC
Afmoniun tccTioN or ihiii quwuhii.

>|6 -*j w}-i
f6 "H wipHmni k
MZ1	
weuam mcii ua -
-»|rafr—- n i^> n?—maitn i/rctia>-
ks	

oott THI PKOJIcr 			
¦raw* A Ponvriu^Jvcn^ will imu^l^jL. kopu ac
CHANOf a QIMfML	WCMASff I—UfOttOT
auoiiu ho mt la	- "
H-
att
| MO |
4()ot|
[«}-
* L, Mil UVEUI
wvoivc VMATVMnM I—1 mo lEuST*"
®	
»«{ MDMI __
0* HOMuuum—Hrah
m ivmum u.1—I
. SOU IW		 iMIill
' HKmct waiMK. m ihiuai
auNoui nT"r^
MfOUWHW	wtTHM
IffClAL liOlttl
H-
-IMVMOMKMTM OffiMDATVM <2«-
• SKOAL HUMAN IfflCfl ttlX UI1X8-
-STMJCTUML CfffCIS (11.9-
liffiamti-
. STMCTUUL CffKIt till -
MALIK ft OBfAM 0HCVS Oil -
WW MALIK (IVCCTIOJ-
MCML MMAI CffKIt ttU UI US-
MO
KNVNL
HO MfACT
IMPACT ANALYSIS
FIGURE 2. FLOW CHART AND WORKSHEET

-------
the flow chart there are three columns that can be checked to indicate the
outcome of the analysis at each branch point. When this flow chart is used
as a worksheet, these columns summarize the noise impact analysis for the
project, showing the stages at whxc h e x x t poxnts o c curred, and c a 1I x ng
attention to aspects of the noise impact receiving explicit evaluation
according to the methods of Chapters 2, 3, and 4.
Usually, there will be not just one version of the proposed project, but
a number of alternative proposals. Each of these alternatives must be ana-
lyzed for noise impacts. There will thus be a flow chart worked through for
each of the alternative schemes. Each of the worksheets, by its summary
columns of checked boxes, will indicate what aspects of the noise impact of
that alternative received expl icit consideration. A comparison of these
columns will facilitate choosing the project alternative with the least noise
impact on the environment.
1.3.1.1 Flow chart
The following discussion of the use of the flow chart provides a brief
explanation of each of the branches. (The section of this report contain-
ing the more detailed discussion is indicated in parentheses on the flow
chart.)
The first step is to provide a general description of the proposed pro-
ject, including those aspects that are expected to contribute to noise im-
pact. The expected noise impact may be either adverse, if the noise environ-
ment would be worsened by the project, or beneficial, if the environment
would be improved. Both the short term and long term effects expected from
the project should be described. For example, the construction of a new air-
port or highway in a sparsely settled region would have as its initial impact
10

-------
an increase in noise that would affect relatively few people. However, the
new facility will attract new people and business which will increase the
nearby population density, unless proper land use planning and implementation
occur. Thus the ultimate noise impact may be significantly greater than that
projected on the basis of the initial effect alone. To evaluate an action
over time, it is suggested that, if feasible, a time interval of 20 years be
used, unless the project will be in existence less than 20 years, in which
case the project lifespan should be used. Thus, the initial impact and the
expected impact after 20 years should both be evaluated. To present a com-
plete picture, the impact after 5, 10, and 15 years might also be presented.
When comparing the impact between projects or alternatives or when assessing
cost-effectiveness, the average impact over a 20 year period may be used.
The first branch point in the flow chart occurs after the potential
noise impacts of the proposed project have been described. At branch points
such as this, each of the available branches (labeled A, B, C and D) should
be taken and followed through to the appropriate indicators in the righthand
columns. At each of the question points following each branch, if the project
will entail no change at all, the 'NO' answer will be followed to 'EXIT', and
the analysis for that branch is complete. In that case, check the box at the
right-hand side of the page under *No environmental change*. If exit points
have been found for each of the branches A, B, C, and D, the noise analysis
need not proceed further; four check marks will be in the column labeled
"No environmental change" at the right of the page and the noise analysis ia
finished. The environmental impact assessment on noise will simply state this
fact. Otherwise, the analysis continues in those branches in which no exit
point has been found.
11

-------
1.3.2 General audible poise
If on Che first branch the project was found to include a potential
change in general audible noise, chapter 2 is appropriate, describing how to
identify and quantify the noise impacts for such an environment. The analysis
begins with the screening step, to determine if the potential change is large
enough to pursue in a detailed analysis (section 2.1). If it is not, the 'NO'
response is again followed to 'EXIT' and the analysis for this branch is
complete.*
If the potential change is large enough to warrant further analysis, the
next question is whether people will be exposed to the noise from the project.
If the answer is 'YES', there are three branches to follow, depending on the
level of noise resulting from the project. The first branch deals with the
range bounded roughly by Ldn values of 55 dB and 75 dB, in which general
health and welfare criteria are the impacts of interest (section 2.2). The
second branch concerns projects which include noise levels above 75 dB (L^n),
Where this occurs, severe health effects due to noise should be considered
(section 2.3). The third branch is for projects which result in levels less
than 55 dB (L
-------
criteria. It should be pointed out that at this branching point, at least one
of the three sound level ranges must lead to the requirement for a noise
impact analysis, and possibly more than one branch will do so. That is, these
categories are exhaustive (i.e., they cover all the possibilities), but they
are not mutually exclusive (i.e., more than one can occur).
Even if people do not normally live or work in the area exposed to the
new noise levels, environmental degradation is still of concern. As such,
this is difficult to quantify but it should be discussed, preferably in terms
of the principal uses made of the affected area (e.g., urban recreation, wil-
derness recreation, wildlife).
1.3.3 Special noises
If the project is found to involve special noises, namely impulse noise,
infrasound, ultrasound, or sounds with negative information content, it is
necessary to follow branch B further (chapter 3). The screening step verifies
that the levels involved are high enough to warrant an analysis.* These
levels are discussed separately for each type of special noise; impulse noise
in section 3.1.1; infrasound in 3.2.1; ultrasound in 3.3.1; and noises with
information content in section 3.4. If people are exposed to one or more of
these special noises, the second part of the appropriate section of chapter 3
is available, describing procedures to be used to discuss and quantify the
impacts. For impulse noise, there is also the possibility of structural
damage (section 3.1.3).
This section of the flow chart is obviously somewhat simplified. If it
were drawn in full detail, there would be a branch such as this for each one
of the four special noises. Thus one should repeat this branch four times.
*See footnote on page 12.
13
-------
The reason for the simplification is that in most (but not all) cases encoun-
tered, no more than one type of special noise will generally be involved.
1.3.4	Vibration
Branch C is followed if the project involves vibration (chapter 4).
Again, there is a screening step to allow an 'EXIT' to 'NO ENVIRONMENTAL
CHANGE' if the levels are low enough (section 4.1.2).* If the levels are
higher than the cut-off, there are two branches to be pursued, the first
if people are exposed (section 4.1.3), and the second if buildings or monu-
ments are exposed (section 4.2). Thus for vibration there are both human
and structural criteria to be considered in assessing potential impact.
1.3.5	Potential changes in population
Some projects entail exposing new populations to existing noise levels,
for example the construction of a housing development in an area adjacent to
a major roadway. Branch D of Figure 2 describes the procedures to be fol-
lowed in such a situation. If the noise levels from existing sources are
presently below 55 dB (L^q), and are expected to remain this low in the
future, Chen there is 'NO IMPACT', and no further analysis is required on
this branch (as long as there are also no special noises encountered). It
should be noted, however, that higher density development (whether residen-
tial, industrial, or commercial) usually brings with it increasing noise
levels, such that it is unlikely that sound levels after project completion
will be as low as they are at present. This 'EXIT' is unlikely to be realis-
tic for any major development. If the noise levels are not below 55 dB (L
-------
branch A, when new noises affected existing populations (sections 2.2, 2.3,
and chapter 3).
1.3.6 Examples
The following examples are presented to illustrate which of the major
branch(es) of the flow chart to use for various projects:
(1)	A project that entails a change in land use may cause only a change
in the existing noise in an area, so only Branch A or B would be fol-
lowed; on the other hand, it may only involve relocation of some of the
population, in which case only Branch D would be followed. If the proj-
ect is expected to cause (or diminish) vibration, Branch C would be
followed. Most land use changes, however, will involve a combination of
A, B, C, and D.
(2)	A project involving the installation of new equipment, or the replace-
ment of old equipment, is likely to require analysis of only branches
A, B, and/or C, since no population shift is likely to be involved.
(3)	A project that consists of a new regulation, or a change in an existing
regulation, might follow either A, B, or D (see discussion in section
1.4.1). For example, a new regulation reducing the noise output of heavy
trucks would change the noise along a highway, and thus Branch A should
be followed. On the other hand, a change in the noise policy of a
federal, state, or local housing authority may alter the distribution of
future dwellings among neighborhoods with different levels of existing
noise; such a regulation would change the population exposed to noise
without affecting the noise anywhere, and hence would warrant analysis
along Branch D.
15
-------
(4)	A new airport, whose primary effect would be increased noise levels in
the neighborhood (Branch A), might impact only presently undeveloped land
'I
that could be spoiled for later residential development by the airport
noise. The future magnitude of the impact would be quite different for
a prospective airport where land is purchased around the proposed site
for controlled leasing to non-aoise-sensitive activities as compared to
one where such precaution was not taken.
(5)	A project that causes a change in the interior noise of aircraft cabins
or a change in the noise insulation of automobile bodies would be ana-
lyzed on a path along Branch A, since it changes the noise environment
in existing spaces with a definable existing population.
1.4 Other considerations
The preceding summary of the structure of these guidelines, and of the
flow chart representing that structure, is written to deal with a proposed
project which will increase noise levels, or in which more people are exposed
to existing noise levels. These are not the only types of projects for which
noise impacts should be considered. This section describes an additional
situation in which noise impacts are a concern—projects aimed at reducing
noise levels. The section also discusses two topics which are relevant to
all three of the chapters which follow: shortened analysis procedures for
temporary projects; and the treatment of uncertainties encountered in the
analysis.
1.4.1 Projects which reduce noise
Two of the examples of proposed actions with noise-related impacts
described on page 1 deal with the reduction of noise. If an action is pro-
posed in order to reduce noise-related impacts, it is immediately obvious
16
-------
that an analysis of those impacts is called for. In most cases it is equally
obvious what kinds of impacts are of interest (e.g., general health and wel-
fare impacts). Eence the flowchart and worksheet are not really needed as
an aid to identifying the area of concern. Instead, one may simply turn to
the appropriate sections of these guidelines for a discussion of useful pro-
cedures for quantifying noise impacts. In other words, the procedures (de-
scribed subsequently) apply equally well to projects which reduce noise as
they do to projects which increase noise. The summary of those procedures
(described previously) is written only in terms of projects which increase
noise.
1.4.2 Temporary projects
At this stage of a noise impact analysis, the specific types of noise
impact requiring detailed documentation will have been identified. This
will have been accomplished either through the use of the worksheet (Figure
2), or by the fact that the action is intended to reduce noise impacts.
The next question to address is how far into the future the analysis should
go. Earlier, it was suggested that either the project duration or twenty
years, whichever is less, should be considered (section 1.3.1), This means
that not only noise levels, but also affected populations, need to be pre-
dicted over the time period of interest. The impacts to consider are not
merely the immediate ones, but long-term ones as well.
Documentation of the impact for temporary projects is simplified by the
fact that population prediction is unnecessary; existing population or land
use information is sufficient. In this context, temporary is taken to mean
less than roughly two years duration. Beyond that length of time, significant
population changes nay take place in an area, so that population forecasts
17
-------
become important. This would be true even for construction projects of longer
duration, which might be in place for 5-10 years.
1.4.3 Uncertainties in the analysis
There will almost always be areas of uncertainty in the noise impact
analysis, usually because of the unavailability of needed factual information.
For example, the projected future traffic volume for a proposed freeway may
be uncertain; the noise of a not-yet-built device may be only approximately
known; or the population estimated to be exposed to various sound levels from
the project may be subject to error. In all cases, a discussion of the prob-
able source and degree of these uncertainties should be included in the
analysis. Perhaps the most suitable approach for this purpose is to take the
upper and lower bound for each of the uncertain quantities that enter into
the analysis, and group the "most favorable" and "least favorable" bounds of
these q entities together to arrive at two estimates of the environmental
noise impact: the best and worst cases that together bracket the range of
likely actual results of proceeding with the proposed project.
18
-------
CHAPTER 2
GENERAL AUDIBLE NOISE
This chapter describes procedures to be followed for analyzing and docu-
menting the noise-related impacts of proposed projects which affect or are
affected by general audible noise. The first section outlines a screening
procedure for determining whether the expected noise levels of the proposed
project are high enough to warrant detailed analysis- As part of that discus-
sion, appropriate noise measures are identified, and methods for estimating
and predicting them are indicated. The second section discusses the general
health and welfare effects of noise on people, which serve as the criteria
for evaluation of noise in most urban and suburban settings. It also pro-
vides a procedure which can be used to summarize these effects with a single
number impact descriptor. The third section discusses the severe health
effects which can be caused by higher levels of noise, and suggests a single
number impact descriptor for these. The fourth section discusses procedures
to follow for projects which will have reasonably low noise levels, but which
are located in very quiet areas—that is, projects for which environmental
degradation is the primary concern. Simplifications of these analysis proce-
dures which can be used for temporary projects are described in the fifth
section. The final section contains a sample application of the procedures,
including samples of the types of tabulation which are recommended.
The criteria used in this chapter are not to be considered all-inclusive;
additional information should be used depending on the scope and magnitude of
the environmental change. The EPA Criteria and Levels documents [7,2] can
be consulted as additional reference sources as well as any other applicable
information.
19
-------
2,1 Basic screening procedures
Some proposed projects will obviously cause severe noise impact on their
surroundings, others may obviously be so quiet as not to change the noise
environment at all. In the first case there is no doubt that a full analysis
of the noise impact is required; in the second case one would simply state,
with minimal documentation, that no impact is expected. About many projects,
however, there will be a question as to whether their noise impact is signifi-
cant enough to warrant a full noise impact analysis. This section offers a
screening test to determine how extensive a noise analysis is needed.
Figure 3 presents a screening diagram for use in determining whether a
full impact analysis is needed. The diagram is based on a comparison of the
existing noise environment and the noise environment due to the proposed
project alone.* This comparison should normally take place at the noise
sensitive location(s) in closest proximity to the proposed project.** So long
as the expected yearly L
-------
~
~ DOCUMENTATION
FULL NOISE ENVIRONMENT	~ ' DEPENDS ON
DOCUMENTATION FOR ALL	FUTURE OF
PROJECTS	/	EXISTING
~	NOISE SOURCES
~
~
ALL PROJECTS
SCREENED OUT
POSSIBLE NOISE
DEGRADATION
ANALYSIS /
80
70
EXISTING Ldn(y)
FIGURE 3. SCREENING DIAGRAM
21
-------
the environment is not significant.* The rationale for the location of the
screening line in Figure 3 is that for any project which is not screened out,
the total environmental noise level after project completion will be increased
from the existing levels. For example, if a project alone is expected to
produce the sane level of noise as the existing yearly L^n, then post-project
total environmental noise will be increased by 3 dB. If the difference
obtained by subtracting the project alone noise levels from the existing
levels is greater than 10 dB, the post-project total noise level will increase
by less than 0.5 dB, which rounds off to a zero increase.
For any new project in which the expected	is greater than 55 dB,
the probability of significant noise reductions of some of the existing
sources should be consxdered. Xf the exxstxng levels are hxgh because of one
major source which is likely to be quieted in the future, then the proposed
project should not be screened out; further analysis is needed since, in
the future, the proposed project could become relatively more dominant than
expe ct ed on the b as xs of exxst xng n o x s e 1eve Is. Xf the exx st xng 1evels are
unlikely to be reduced, then the project can be screened out.** However, even
if no reductions are likely an impact analysis can still be carried out, and
in many instances is strongly encouraged, based on idealized or hoped for
future noise levels for the area. In other words, noise impact analysis is
recommended for noisy projects even if they are in already noisy areas.
*I£ the project is temporary with a duration of less than one year, expected
yearly L(jn should not be used. Rather, it is more appropriate to use the
day-night sound level averaged over the actual duration of the project (see
Section 2.5). In any case, existing yearly L^n is always used.
**Even if existing levels are unlikeLy to be reduced, a further analysis'may
still be needed in cases where the project noise differs significantly•in
quality or temporal character from existing sources.
22
-------
The diagonal line in Figure 3 continues as the indicator of screened-out
projects to very low noise levels. For proposed projects which are above
this line, but produce levels below L
-------
represent levels measured under average conditions, or, if conditions vary
during the year, weighted averages of levels at the different times of year.
In some instances, a rough approximation to annual average conditions or
noise levels will be sufficient; in others, it will be necessary to be more
precise. For example, noise levels for some airports are reported for an
average busy day, rather than an annual average. If the project under analy-
sis is land-use development, it is quite reasonable to use such existing
noise information, even though it is not exactly the annual average. The error
in the data is small enough that the cost of a more exact estimate of the
annual average is not warranted. On the other hand, if the project being
analyzed involves a change in airport use (for example Sunday flights when
there were previously none) the noise level typical of an average busy day mr*y
lead to nonsensical results. (The busy-day level would be reduced, in the
example, if the aircraft noise on Sunday was less than the average on otk;r
busy days—even though over the year more noise was being produced because of
the added operations.) Approximations for the annual average L can be
da
very useful shortcuts, but need to be applied with careful judgment.
Day-night sound level is the primary measure of general audible noise,
and is appropriate for noise environments that affect a community over an
entire 24-hour day. There are two kinds of situations where such a measure
is not appropriate, however. The first kind consists of those situations
in which it is desirable to assess the effect of a noise environment on an
activity of less than 24-hour duration. An example is the effect of noise
on speech communication in classrooms or in offices. In these situations it
is useful to consider the equivalent sound level,	over the time
period of interest (T) , for example one hour or eight hours,	or
Leq(8)>-
24
-------
The second kind of situat ion covers those xzx ^^hich the Tioxse is ^xot
present for enough of the day to greatly affect the L reading, but is
dn
still subjectively judged as intrusive and disruptive when it is present.
Examples of such noise sources may include motorcycle passbya, trains, and
specific aircraft flyovers. The appropriate sound measure for such an event
is the cumulated sound produced by the single event, the A-weighted sound
exposure level, Lg. It is a measure of accumulated, not average, sound
energy.
Precise mathematical descriptions of all these measures are provided in
Appendix A. All are expressed in A-weighted decibels; the reference sound
pressure is 20 micropascals.
2.1.2 Determining the yearly day-night sound level
For the screening procedure, two yearly Ldn values need to be deter-
mined: the existing levels; and the levels expected to be caused by the
proposed project. In addition, for the impact assessment it will be necessary
to estimate the future yearly Ldn values in the area if the project is not
constructed, (The total post-project noise level can then be calculated as the
(logarithmic) sum of the project levels and the future levels in the absence
of the project.*)
Determining I»jn(y) by direct measurement. To establish the existing
noise exposure accurately, field measurements are oftentimes the preferred ap-
proach. Unfortunately, such measurements can be expensive and time-consuming.
Nonetheless, measurements may be warranted. For example, if the present
average sound levels are already high, so that the noise impact of a new
*See Appendix E for examples on how to calculate logarithmic sums of project
levels and future levels in the absence of the project.
25
-------
project will not be much greater, or may be even less than the impact from
the existing noise environment, it may behoove the applicant to conduct a
measurement program, so as to predict the noise impact more accurately.
When an existing noise environment is to be determined by direct measure-
ment , it will be necessary to make measurements at a number of locations suffi-
cient to establish a credible baseline for estimating total impact. The number
of measurement locations and their geographic disposition will depend on the
spatial extent of the impact expected to be produced by the project.
Measurement periods and the time intervals between them should be deter-
mined by the characteristics of the existing noise, in order to obtain a
reliable estimate of yearly L^. If the existing noise is expected to be
substantially the same from day to day, measurements during a single typical
24-hour period may be adequate. Locations where the noise is caused primar-
ily by well-established motor vehicle traffic patterns are an example. In
other situations where strong daily, weekly, monthly, or seasonal effects
occur, it may be necessary to measure for a number of different daily periods
suitably chosen to account properly for these variations. In some particular
situations, the .variations may be large enough to make measurement practi-
cally infeasible. A case in point might be in the vicinity of an airport
with more than one runway which has no on-going noise monitoring program.
The most reliable temporal data are obtained by techniques that approach
continuous measuranent of the sound level over the time period in question.
In some instances it may be reasonable to obtain or sample measurements over
only fractions of the total time—e.g., several minutes per hour. How-
ever, any measurement method used to approximate continuous measurement of
should be justified by adequate technical reasons and data to show the
26
-------
accuracy of the procedure when applied to the specific noise sources being
described.
If field measurements are undertaken, they should be conducted in accor—
dance with accepted procedures [9].
Determining Lda(y) by the use of engineering prediction models. Sev-
eral kinds of noise have been extensively studied, particularly the noise of
transportation, and procedures have been developed for calculating day-night
sound levels based on the type of noise source and operational considerations.
Procedures for estimating the noise of specific sources such as roadways
[10,11,12,13] and aircraft near airports [13,14,15] are available and may be
easily adopted for those situations in which the existing noise environment is
dominated by a major noise source. A partial bibliography of some of these
engineering prediction models for roadways, aircraft, transmission lines,
outdoor recreational sources, and high-energy impulsive noise is included at
the end of Appendix E.
Determining Ldn(y) from the population density. Where no dominant
source of this nature is present, the existing noise environment may be con-
sidered to be caused primarily by local automotive traffic noise. For these
instances, the day-night sound level may be estimated on the basis of popula-
tion density in accordance with the values listed in Table 2. For convenience,
the population density values in Table 2 are listed in terms of both persons
per square mile, and persons per square kilometer. The data contained in
Table 2 are based on the equation:
l*dn * 10 log P + 22 dB	Iqn. 1
where p is the population density in persons per square mile. This relation-
ship was derived from measurements at 130 urban locations [16]. The equation
27
-------
has a standard error of 4 dB, which means chat the 95 percent confidence
interval around the estimate is roughly +8 dB. The reliability of the
relationship is approximated by the correlation coefficient of 0.723 between
and the log of Che population density over the 130 data points. This
can be interpreted as xndicatmg that the log of the population density
explains 52 percent of the variation in L^. This amount of uncertainty
about the true	may or may not be acceptable for a given project. If
it is not, measurements or source-based predictions are recommended.
The levels shorn in the table represent average values for residential
areas that are not in the vicinity of an especially noisy existing source such
as an airport, a freeway, a railroad, or a switching yard. If such a noise
source exists, its contribution to the existing L,jn should be estimated
separately, and then combined with the level given in Table 2. The values in
the table are representative of space average values over areas of the order
2
of 1 km (0.4 sq. mile), or larger, for typical urban conditions.
For purposes of estimating the existing noise in relation to permanent
changes in areas with population density greater than 20,000 persons/sq. mile,
the day-night sound level should be taken as 65 dB. Higher estimates of the
background noise by the use of equation 1 require specific justification
such as direct measurements or detailed calculations based on existing noise
sources. The reason for this suggestion is to avoid obtaining low numbers for
the impact of noisy projects in heavily populated areas. This is in line with
the discussion of accounting for existing noisy areas when using the screening
diagram. Particularly when an area is noisy because of high population den-
sity it is important to consider very carefully any project which will add to
the noise in the area, and therefore not to initially screen it out by using
high estimates of existing levels.
28
-------
TABLE 2
YEARLY DAY-NIGHT SOUND LEVEL AS ESTIMATED BY POPULATION DENSITY
(To be used only for residential neighborhoods where
there is no well-defined source of noise)
Population Density L
-------
use the information in these guidelines to express the impact of the noise
on people.
If prediction techniques are not available for a particular project, for
example a specific industrial installation, measurement of noise levels at a
similar existing installation is appropriate, although an engineering descrip-
tion should be included of the reasons for anticipating such similarities in a
new installation. Likewise, where the introduction of a new noise source is
anticipated and neither an existing approved procedure nor a similar installa-
tion is available, an engineering description of the procedure employed to
estimate noise emissions should be provided in adequate detail for technical
evaluation of its acceptability.
For predicting future noise levels in the absence of the proposed pro-
ject, the available methods are (1) extrapolation of existing levels to the
future, (2) the use of source-specific prediction techniques, or (3) the use
of equation 1.
2.1.3 Determining the population affected by the noise of the proposed
project
For each of the alternatives that involves the introduction of some form
of a new noise source, the affected population is defined as that population
experiencing sound levels produced by the new noise source above a specified
yearly L
-------
**dn* *"or example, if the existing yearly L,jn is 60 dB, it is suggested to
start with a base L^n(y) of 50 dB, if possible, in order to determine the
number of people affected by the project noise. In some instances, however,
it will not be feasible to predict project noise levels to such low values,
(An example of such an instance would be around commercial airports, where
existing prediction techniques are not particularly reliable below an of
65 dB, due to lack of information about aircraft flight track usage.) In such
cases, it is still imperative to consider as large a range of levels as is
feasible. A difference of 20 dB between the maximum L
-------
no person exposed to project noise levels less than the base L,jn(y) would be
regarded as impacted.
There are cases when, over time, people will move into or out of a proj-
ect area at the same time the project is expanding and environmental noise
levels are increasing. Such changes in population may be entirely unrelated
to the project under analysis. In these cases it may be necessary to define
several base populations or base areas, one for each year of interest. (See
Appendix E, section E.2 for an example of this type of analysis.)
There are actions that do not add new noise sources, but only change the
noise output of existing sources. In these cases, the changed source should
be treated as a new source for purposes of determining the base population.
There are actions that will move people into noisy areas. For these
cases, the base peculation will be the total population who will be living
in an area where th~. existing yearly Ldn is greater than 55 dl.
There are actions which affect large segments of the population that are
not easily related to specific areas. Laws and regulations that directly
affect mobile noise sources are examples of such actions. For actions affect-
ing regulation of noise sources in general, the base population might best
be described as the total population experiencing day-night sound levels
above 55 decibels from such sources. For actions affecting source control
for equipment operators, the base population might be only the users of the
specific noise source. In the final analysis, the preparer of a noise impact
analysis must use his or her judgment. In all cases, an explanation should be
included in the final report of how the base population was determined.
Population estimates for residential areas identified in the analysis
may be taken directly from census tract data, local master plans, or by
counting residential units identified on aerial photographs of the area.
32
-------
Non-residential populations may be estimated from industrial, commercial, or
public facility employee statistics; student enrollments and employee statis-
tics can be used to estimate school populations. Population estimates should
strive to identify total populations within an accuracy of +10 percent. It is
recognized that in many situations such a degree of accuracy is unattainable.
In such cases the users of these guidelines should put forth the best gener-
alized estimates possible, documenting the basis or procedures employed in
making these estimates. One way to deal with uncertainty in predicting future
populations is to use the local community's land use plans or zoning designa-
tions, whenever they exist, to estimate the most likely future population
density.
2.2 Health and welfare effects
This section deals with the most commonly experienced noise problems,
the general health and welfare effects of noise due to the noise environment
encountered ia most urban and suburban areas. Those effects are the major
concern at yearly L(jn values which range approximately from 55 dB to 75 dB.
Summaries of these effects are described in Appendix C. Above 75 dB, the
possibility of severe health effects need to be considered (see section 2.3.)
in addition to the effects discussed here. The first subsection describes the
health and welfare criteria which apply in this range of general audible
noise, and the second covers the procedures to be used to quantify those
effects.
2.2.1 Human noise exposure criteria
As the primary criterion for evaluating the impact of noise on people,
the effect on "public health and welfare" was selected xn the Levels Docu-
ment [23. Interference with speech communication, with general well-being,
and with sleep are related to the general annoyance produced by the noise
-------
environment, and were accepted as indicators of effects on public health and
welfare. The same criteria are proposed here as the basis for environmental
impact assessment.
A summary of the expected effects of noise on human activities for out-
door yearly day-night sound levels of 55, 60, 65, 70, and 75 dB, in terms of
health effects, interference with speech communication, community reaction,
annoyance, and attitude towards the area is provided in Appendix C. Basic
information in these tables on speech intelligibility and general community
reaction was derived from the Levels Document [2]. The relationships given
in the Levels Document between noise and annoyance have been modified in the
light of a substantially increased set of data subsequently available [6].
These tables allow the preparer of a noise analysis to make an explicit
statement as to the expected impact of any day-night sound level.
In order to achieve the simplicity which these guidelines are intended
to promote, it is desirable to be able to summarize these several health and
welfare effects with a single indicator. The response of interest is the
general adverse reaction of people to noise, which includes speech interfer-
ence, sleep interference, desire for a tranquil environment, and the ability
to use the telephone, radio, and television satisfactorily. A measure of this
response is the percentage of people in a population that feels high annoy-
ance about noise of a specified level. High annoyance is selected on both
theoretical and practical grounds. First, it arises as a consequence of
the activity interference and interruption caused by noise [17], and there-
fore summarizes all the effects better than any one of the direct effects
would. Second, there is available a large set of data which allows reponse,
expressed as percentage of a population highly annoyed, to be characterized
by a single functional relationship of the noise environment [6].
34
-------
The percentage highly annoyed is used rather than the percentage at all
annoyed for a number o£ reasons (6, pp. 378-3791. Perhaps the most important
of these is that when people are highly annoyed by noise the effects of non-
acoustical variables are reduced, and the correlation between noise exposure
and the expressed subjective reaction is high. This is not to say that all
individuals have the same susceptibility to noise; they do not. Even groups
of people may vary in their response to noise, depending on previous exposure,
age, socio-economic status, political cohesiveness and other social variables.
In the aggregate, however, for residential locations, the average response
of groups of people, as measured by the percentage highly annoyed, is quite
stably related to cumulative exposure to noise as expressed in a measure such
as X* dn *
For schools, offices, and similar spaces where ease of speech communica-
tion is of primary concern, the same relationship can be used to estimate
the potential average response of people, taken as a group, ignoring individ-
ual variations from person to person.
Data used to relate annoyance to noise environment in the Levels Document
[2] was based on two social surveys around airports in the United States and
England. Data have now been analyzed from 19 social surveys (in 9 countries)
associated with aircraft, urban traffic, freeway traffic, and railroad noise
[6]. These data allow a much more definitive relationship to be developed
between percentage of the population highly annoyed and average noise level.
The data support the previous assumption that the statistical relationship
between population annoyance and noise level is essentially independent of
the type of noise source [18].
The results of this synthesis show quite clearly that the best fit of
response data to average sound level is provided by a curvilinear function;
originally a cubic equation was used in the regression analyses. Further, 12
-------
of the surveys, covering aircraft, railroads, urban traffic, and expressway
traffic as noise sources, "clustered" closely around an average curve for the
set of data, as shown in Figure 4. The remaining 7 surveys showed similarly
shaped annoyance/sound level functions, but deviated in differing detail from
the 12 clustering surveys for various qualitative reasons [6]. It is worth
noting that the average of the non-clustering surveys was essentially the
sane as the average for the clustering surveys.
Based on these data, Schultz proposes the following equation "as the
best currently available estimate of public annoyance due to transportation
noise of all kinds" [6, p. 382], relating percent highly annoyed, (ZHA),
to day-night sound level:
2	3
ZBA ¦ 0.8553 Ldn - 0.0401 Ldn + 0.00047 ldn	Eqn, 2a
This expression represents the least-squares fit of percent highly annoyed
to day-night sound level for the clustering survey data.
A second form of this equation, based on two power law functions, is
preferred on the grounds that it suggests an explanation for the behavior
represented in equation 2a. At lower levels, the first power function
represents increasing awareness, or arousal. At higher levels, annoyance
increases at the same rate as the well-known loudness function, represented
by the second power function. The smoothed version of the function based
on the two power law functions is expressed as*:
~Another very useful and simpler expression which approximates the annoyance
function is:
I + e(10.43 - 0.132 Ldn)
This expression has the particular advantage of not allowing predicted values
to go below zero percent or above 100 percent.
36
-------
100
O
u
>
<
>
_>
X
a
a
K
1ST HEATHROW A/C (1961)
FRENCH A/C (1966)
2ND HEATHROW A/C {1967]
MUNICH A/C (1969)
PARIS STREET (1969)
SWEDISH A/C {1972)
SWISS ROAD (1972)
LONDON STREET (1972)
SWISS A/C (1973)
FRENCH RR (1973)
U.S. STREET (1974
LAX (1974)
•*«**
?
60	70
L,jn (DECIBELS)
FIGURE 4. SUMMARY OF ANNOYANCE DATA FROM
12 SURVEYS SHOWING CLOSE AGREEMENT
SOURCE: SCHULT2 [6]
37
-------
(1.24 * 10~4) CIO0"103 Lda>
(1.43 x 10"4) (100,08 Ldt») ~ (0.2) (10°"°3 Ldn)	Eqn. 2b
In the absence of any studies relating average response to noise level
for non-transportation sources, equation 2b has been adopted in these guide-
lines for use as the criterion for all noise sources. If information becomes
available which identifies a different relationship for certain sources, the
guidelines may be revised accordingly.
This function for the percentage highly annoyed differs from previously
suggested equations, including the one in the Levels Document [2, p. D-27],
as is illustrated in Figure 5. the relationship shown in the Levels Document
was taken from a study by an EPA Task Group under the EPA, Aircraft/Airport
Noise Study in 1973 119]. In this study, social survey data from the first
study around Heathrow airport in England [20], and from the Tracor study of
U.S. airports [21] were combined to develop a relationship between "percent
highly annoyed" and day-night sound level. This function was expressed as:
% Highly Annoyed "1.8 (L^ - 46)	Eqn. 3
The Task Group also noted a similar relationship developed in an OECD study
[22] that used the relationship:
Z Highly Annoyed a 2 (L^n - 50)	Eqn. 4
This equation wa3 also based on airport noise studies. The primary reason
for these differences is a redefinition of what is meant by highly annoyed.
In fact, the Heathrow study is included in the clustering surveys (Figure
4). As Schultz's paper makes clear [6, pp. 391-392], the annoyance scale
used in the first Heathrow study requires some interpretation; it is not
a direct question about degree of annoyance. The earlier analysis (Iqn. 3)
considered the top three scale points as highly annoyed; Schultz used only
38
-------
so r
o
iii
o
z
LEVELS DOCUMENT
(HEATHROW ft TRACOR)
Z
<
5
NEW ANNOYANCE FUNCTION
50
80
60
90
40
DAY—NIGHT SOUND LEVEL—DECIBELS
FIGURE 5. COMPARISON OF NEW ANNOYANCE
FUNCTION WITH PREVIOUS FUNCTIONS
39
-------
the Cop two. His discussion is persuasive, and his function has been adopted
for these guidelines.
It is important to point out that this redefinition of annoyance does
not affect the conclusions reached in the Levels document, because that docu-
ment relied on speech and sleep interference indicators to identify the actual
levels which were "requisite to protect the public health and welfare with an
adequate margin of safety," That approach led to the statements that a day-
night sound level of 55 decibels in residential areas will result in negligi-
ble impact on public health and welfare and that the degree of impact will
increase as the day-night sound level increases. The EPA Levels Document [2]
asserts that no significant effects on public health and welfare occur, for
the most sensitive portion of the population and with an adequate margin of
safety, if the prevailing day-night sound level is less than 55 decibels. The
difficulty with using annoyance for such a calculation is obvious in Figure 5:
there are still some people affected at sound levels as low as 45 d& ^Ldn5 *
These guidelines, then, use as the criterion in populated areas the function
given by Iqn. 2, which shows some impact at levels as low as 45 dB, impact
which is fairly low into levels in the low 6Q*s (dB) , and impact which begins
to increase fairly rapidly above 65 or 70 dB (Ldn).
For those events in which the single event measure, sound exposure
level, is used to describe the noise environment, the previous discussion
will not apply. Information characterizing response as a function of sound
exposure level is not readily available. Some information can be approxi-
mated for sleep interference [23,24,25,26] and speech interference [24,26],
but it is not as easily dealt with as is the information on Ljn.
40
-------
2.2.2 Quantification of the noise impact
The impact of a noise environment on people regularly experiencing the
environment is the degree to which the noise interferes with various activi-
ties such as speech, sleep, listening to radio and television (i.e., the
peaceful pursuit of normal activities), and the degree to which it may impair
health, through, for example, the inducement of hearing loss, Sound levels
produced by sources being considered in an environmental assessment will
generally vary with distance from the source, sometimes over a large geo-
graphic area. As a consequence, people occupying different geographic areas
will experience different sound levels. The total impact of a particular
noise environment is a function of both sound level and the size of the
population experiencing a particular value of sound Level.
The first step in describing the noise impact of an action is to tabulate
the number of people regularly experiencing various sound levels. In many
cases, particularly those in which noise impacts must be compared with a
variety of other costs and benefits, such a tabulation is insufficient,
because it contains too much information. In those cases, it is desirable to
derive a single number which represents quantitatively the integrated impact
of the action on the total population experiencing the different sound levels.
This single number quantification is defined below as the sound level-weighted
population, LWP. Sound level-weighted population, together with the tabula-
tions of populations experiencing sound levels of a specified value, consti-
tute the minimum quantification of environmental impact of noise recommended
in these guidelines. This subsection describes procedures for preparing the
tabulations, and for calculating the sound level-weighted population. It also
describes a useful second descriptor of noise impact, the noise impact index,
Nil, which is formed by the ratio of sound level-weighted population to the
41
-------
total base population. The procedures proposed here do not rely on establish-
ing specific criterion noise levels for different land use categories. (For
information on criterion levels suggested by different organizations, see
Appendix B.)
a. Hecessary tables - As a minimum the data characterizing the noise
impact should be tabulated in a set of summary tables. Typical tables are
included in the example in section 2.6 (Tables 6 through 9). For a given year
the areas and population are to be listed against the yearly day-night sound
level at increments not greater than five decibels, for the following esti-
mated noise environments:
CD without the project's existence;
(2)	due solely to the project action;
(3)	due to all sources including the project action.
All three tables may not always be iecessary, especially if there are insig-
nificant differences between any two of the tables.
If the tables are properly constructed, the total population and/or land
area for each of the three conditions will be equal (i.e., will equal the base
population or area defined in section 2.1.3). The tables should include enough
increments of yearly that all residential populations, industrial, commer-
cial land and special situations experiencing L^j, values above the base
are included.
The column headings might typically include: total land area, industrial/
commercial land area, residential land area, industrial/commercial employees,
residential population, and special situations. Depending upon local condi-
tions, different classifications of land use may be appropriate. Industrial/
commercial land area is meant to include all land not considered as residen-
tial or associated with special functions. This land area would include farm
42
-------
land, undeveloped land, industrial planes, and similar uses. Depending on
local plans, this category may be further broken down. Residential land
includes all land associated with a residential population. It may include
land actually zoned commercial or industrial. For residences on farm lands,
approximately 1 acre should be considered as residential land for each sepa-
rate residence.
Special situations are those situations which must be highlighted or
treated separately in order to represent the impact properly. Situations
of this category can be religious facilities, outdoor auditoriums, schools,
precision laboratories, hospitals, etc. The detail to which each special
situation should be discussed will depend on the size of the project and the
size of the area being evaluated. Special situations should be combined as
necessary to keep the total number o " special situations within reason (nor-
mally less than 20 or 30 items). On- useful approach to the listing of spe-
cial situations is to number each o .a, and then to use this number in the
special situation column to indicate the corresponding L^n for that situa-
tion (see examples, section 2.6, Tables 5 through 8).
If there are more than a few special situations, an additional table
summarizing them will also be useful (Table 9 in the example in section 2.6).
This should list the number of exposed people for each situation. At some
locations the population does not remain constant from day to day, week to
week, or month to month. Examples of such places are churches, parks, and
stadiums. In such situations the population entered in the special situation
table is the time-weighted average number of people present during the year.
This number should be calculated by summing the products of the number of
people using a facility, multiplied by the number of hours these people are
present in the facility during a year, and dividing by the total number of
43
-------
hours in a year. If a noise measure other than yearly Ldn is being used,
the average number of people can he calculated similarly for that time period,
such as the working day for office buildings. The concept of average number
should not be used for residential areas.
Formats other than that used in Tables 6 to 9 may be appropriate and may
be used; however, the information conveyed to the reader should be effectively
the same as or greater than is contained in these tables.
For each alternative of a permanent project or action, a separate set of
tables as outlined above should be prepared for (1) the first year of the
commencement of the project, (2) the last year before the end of the project
(or at the 20-year point, whichever is shorter), and (3) the worst case year
if such a year is not the first or last year. In many cases, only one of
these sets will be necessary because the conditions with respect to time
can be expected to remain reasonably constant. By "reasonably constant,"
it is meant that the change in exposed population will be small enough so
any resulting errors are consistent with the error in the overall analysis.
In addition to the tables, it would be helpful to present a map or draw-
ing of the area including surrounding facilities such as airports, factories,
highways, or electrical plants, with contours representing constant values of
yearly day-night sound level. In general, the decibel increments between
contours should be consistent with the tables as discussed above. Other con-
tours may be presented as needed. There should be a set of contours for each
of the alternatives studied.
b, Sound level-weighted population - For those projects in which it
is necessary to compare or trade off noise impacts with other costs and bene-
fits of a proposed project, a compilation of the data characterizing noise
impacts into the tables described above will usually not prove sufficient.
44
-------
The tables contain too much information for easy comparison to be possible.
A single number representation, combining the extensity (number of people
exposed) and intensity (severity of the exposure) of the noise impact is
desirable. Using the criterion function based on the percentage highly
annoyed (Eqn. 2), described in section 2.2.1., such a single-number index
can be constructed which summarizes the impact in terms of the total number
of people who respond adversely to the effects of noise.
Several assumptions are made in this method of analysis,
(1)	The intensity of human response is a measurable coasequeace of
equivalent sound level, and in the aoise range of interest here (namely that
generally encountered in populated areas), is appropriately measured as the
percentage of the population which is highly annoyed.
(2)	When measured this way, it is clear that the impact of high
noise levels on a small number of people is equivalent to the impact of lower
noise levels on a larger number of people in an overall evaluation, when both
yield the same number of people responding adversely. Thus the properties of
intensity (level of sound) and extensity (number of people affected by the
sound) can be combined mathematically.
(3)	On the basis of these two assumptions one can ascribe differing
numerical degrees of impact to different segments of the population of con-
cern, depending on the equivalent sound level, and can sum over all of these
segments to obtain the total impact (total number responding adversely).
On the basis of these assumptions, the following equation is obtained
for the sound level-weighted population, LWP:
where P(Ldn) is the population distribution function, W(Ljjn) is the weighting
function described in Equation 2b, characterizing the severity of the impact
LOT »
Eqn. 5
45
-------
as a function of day-night sound level (Table 3), and d(Ldn) is the differen-
tial change in day-night sound level. Although Table 3 contains values for
Ldn as low as 35 dB, the values below 45 dB should be used only with great
caution, as they represent extrapolation beyond the range of the data [6], In
any event, for most projects in populated areas, the future noise level even
without the project will probably be considerably higher than the 45 dB limit
of the data.
It is usually not necessary or possible to use the integral form to com-
pute LWP. Sufficient accuracy is obtained by taking average values of the
weighting function between equal decibel increments, up to 5 decibels in
size, and replacing the integrals by summations of successive increments in
average sound level:
LWP - £F(Ldn)i • W(Ldn)i	£qn. 6
where i indexes the successive increments in average sound level.
c, Noise impact index - The sound level-weighted population is a mea-
sure of the total noise impact of a proposed alternative. In many cases it
will be the only summary indicator needed for comparing alternatives. In
other cases, where the base population is not constant (for example when com-
paring projects in different locations), the noise impact index (Nil) will be
a useful concept for comparing the relative impact of one noise environment
with that of another. It is defined as the sound level-weighted population
divided by the total population under consideration:
^P(Ldn)i W(Ldn)i
LWP			Eqn. 7
?Total	2^LdnH
where the functions are the same as described above, and	is equal to
the base population (defined in section 2.1.3).
46
-------
TABLE 3
VALUES OF THE WEIGHTING FUNCTION FOR GENERAL ADVERSE RESPONSE*
X	[W(Ldn) - (O.Ol)ZHA]
^dn
WWn)
35
0.002
35.5
0.002
36
0.003
36.5
0.003
37
0.003
37.5
0.003
38
0.003
38.5
0.003
39
0.004
39.5
0.004
40
0.005
40.5
0.005
41
0.006
41.5
0.006
42
0.007
42.5
0.007
43
0.008
43.5
0.008
44
0,009
44.5
0.010
45
0.011
45.5
0.011
46
0.012
46.5
0.013
47
0.014
47.5
0.015
48
0.017
48.5
0.020
49
0.019
49.5
0.021
50
0.023
50.5
0.024
51
0.026
51.5
0.028
**dn
W(L,jn)
52
0.030
52.5
0.032
53
0.035
53.5
0.037
54
0.040
54.5
0.043
55
0.046
55.5
0.049
56
0.052
56.5
0.056
57
0.060
57.5
0.064
58
0.068
58.5
0.072
59
0.077
59.5
0.082
60
0.087
60.5
0.092
61
0.098
61.5
0.104
62
0.110
62,5
0.116
63
0.123
63.5
0.130
64
0.137
64.5
0,144
65
0.152
65.5
0.160
66
0.168
66.5
0.176
67
0.185
67.5
0.194
68
0.204
68.5
0.214
**dn	^^dn)
69	0.224
69.5	0.234
70	0.245
70.5	0.256
71	0.267
71.5	0.279
72	0.291
72.5	0.303
73	0.315
73.5	0.328
74	0.341
74.5	0.355
75	0.369
75.5	0.383
76	0.397
76.5	0.412
77	0.427
77.5	0.443
78	0.459
78.5	0.475
79	0.492
79.5	0.509
80	0.526
80.5	0.544
81	0.562
81.5	0.581
82	0.600
82.5	0.620
83	0.640
83.5	0.660
84	0.681
84.5	0.703
85	0.725
~When using decibel bands of increments greater than 1 dB, use the Weighting
Function that corresponds to the mid-point of the band. For example, to
determine W(Ljjn) for the 60-65 dB band, use 62.5 dB (the mid-point of the
band) to estimate the Weighting Function, which in this example, would be
approximately 0.116.
47
-------
d.	Change in level-weighted population and relative change in impact -
A primary concern in an environmental noise assessment is a comparison of (1)
the effect of the action on the noise environment with (2) the environment
before the action was to take place. Two additional descriptors of this
change due to the action are useful. The first descriptor is simply the
numerical change in sound level-weighted populations before and after the
action, the change being an increase or decrease in sound level-weighted
population (or the neutral effect case, no change). The second descriptor
is the relative change in impact (RCl), where the effect of the action is
expressed as the value of the change in the sound level-weighted population
after the action, divided by the sound level-weighted population before the
change:
RCt . LW?* " LWPb	3
LWF.
0
where LWP^ is the impact after the action or project is in place, and LWP^
is the impact before the action is taken.
e.	Level-weighted area - In those rare cases where it is known that an
area will be developed, but there is no information with which to predict the
future population, it may be necessary to calculate a level-weighted area, as
a proxy for the population impacts. Such a calculation would be equivalent
to that for level-weighted population (equation 6), but would use the tabula-
tion of area within decibel intervals, rather than population, assuming, in
effect, a constant and undefined population density.
f.	General discussion - A number of different noise impact descriptors
are available, based on the four single-number indexes (level-weighted popu-
lation, noise impact index, change in level-weighted population, and relative
change in impact) and the three noise characterizations (the project alone,
48
-------
the environment without the project, and the total future noise environment
obtained by combining the other two}* The result is almost a confusion of
supposedly simplifying descriptors. Two or three of these will be most useful
in each case, depending on the relationship between project levels and ex-
pected levels without it (Figure 6). Where existing levels are already high,
the level-weighted population or noise impact index based on the project noise
alone is suggested as the best descriptor. The other descriptors will mini-
mize the impact by putting it on relative terms. 'Where project levels are
much higher than existing levels, the project levels will dominate the com-
bined levels, so either will give the same result. Where project levels are
similar to existing levels, it is necessary to use the combined levels to
identify the full impact.
For projects which will move people into areas with Ldn values above
55 dB, and for projects which reduce noise, Figure 6 is not applicable. Proj-
ects, such as housing developments in areas with Ldn above 55 dB, need to be
evaluated in terms of the level-weighted population or noise impact index
based on the non-residential noises to which they will be exposed (e.g. road
traffic or aircraft noise). The only basis for calculating the change in
level-weighted population or relative change in impact which might be useful
in such a situation is one based on the national average Nil, which has been
calculated to be 0.35. Projects which reduce noise, on the other hand,
should be evaluated on the basis of the change in level-weighted population,
or relative change in impact. Since the project is proposed to reduce noise,
it is obviously the reduction or change which is o£ interest.
Relationships between annoyance and average sound level have been used
previously to define a weighting function for the numerical evaluation of
impacts. It is useful to compare' the present function (Eqn. 2 and Table 3)
49
-------
UJ
Z
o
-I
<
o
c
-I
~
LU
|h»
u
UJ
o.
X
UJ
70
LWP {COMBINED NOISE LEVELS)
OR Nil (COMBINED NOISE LEVELS}
RCt (COMPARING COMBINED
LEVELS WITH LEVELS
EXPECTED WITHOUT
THE PROJECT}
SPECIAL
ANALYSIS
L.
LWP (PROJECT ALONE)
OR
Nil (PROJECT ALONE)
ALL PROJECTS
SCREENED OUT
80
90
EXPECTED FUTURE Ldn(y) WITHOUT PROJECT
FIGURE 6. SUGGESTED DESCRIPTORS FOR VARIOUS SITUATIONS

50
-------
Co Che one used earlier by EPA, which was firsC introduced in Che fractional
impact method developed initially for use in Che analysis of highway noise
problems [27], This meChod Cook inCo accounC Che daCa and recommendations
boCh of Che EPA Levels document [2], and " of the earlier report on Impact
Characterizacion of Noise [19], which indicaCe thaC a community would not be
expected to exhibit significant reacCion at noise exposures of L,jn ¦ 55 dB or
below, but would be expected to show strong, organized reaction at ¦ 75 dl
and higher. Using these two anchor points and the linear relationship of
Equations 3 and 4, a weighting function called fractional impact (F.I.) was
defined to be zero at L,jn ¦ 55 dB, and unity at ¦ 75 dB, varying linearly
wich average sound level, such that:
F.I. ¦ 0.05 (Ldn - 55)	Eqn. 9
The weighting function for F.I. has been used by EPA in impact analyses of
a number of potential regulatory actions.
Several features of equation 9 are unsatisfactory. It is not likely
chac communicy response is adequaCely described with a linear function of
average noise level over a wide range of levels. Even though the data from
the individual social surveys are reasonably well fitted by linear regres-
sions over Che limiced range of levels represented in the separate surveys,
the individual survey results indicaCe chat the race of change of annoyance
with sound level is greater at higher sound levels than at lower sound levels.
Moreover, the choice of an arbitrary zero at = 55 dB is not easily justi-
fied. Finally, few data from noise sources other than aircraft were available
at the time the original weighting functions were developed, and a weighting
function derived only from aircraft-related social surveys may not be satis-
factory for use in evaluating other sources of noise.
51
-------
Despite these flaws, however, this linear function is quite similar in
its relative ratings to the curvilinear function used in this document (Eqn.
2), If the two functions are placed on the same scale (Figure 7), it can be
seen that, in the day-night sound level range of 55 to 80 decibels, this
linear weighting function will generate relative values for level-weighted
population that differ only by the order of one percent from the curvilinear
weighting function in many applications. The change in scales necessary to
make this comparison stems from the fact that fractional impact was defined
to be unity at 1^ » 75 dB, while the present function is based on the number
of people reporting a high degree of annoyance in a social survey situation.
Both are equally legitimate interpretations of available impact: the first
provides an indicator of absolute impact, while the second is more easily
understandable in comparisons with other costs „nd benefits of proposed
projects. Because the linear function (Eqn. 9) closely approximates the
curvilinear relationship (Eqn. 2) between the da'-night sound level range
of 55 to 80 dB, the user may wish to employ the more simple linear relation-
ship in some cases.
2.3 Severe health effects
In some high level noise environments people will be exposed regularly
to 24-hour equivalent sound levels in excess of 70 decibels. In these envi-
ronments special consideration should be given to the potential for severe
health effects. This section discusses the criteria to be used for describing
severe health effects, and then describes a procedure for calculating a single
number index, analogous to the level-weighted population index, for statisti-
cally summarizing expected severe health effects.
52
-------
o
UJ
>
o
z
z
<
>
z
2
z
H
Z
UJ
U
cc
UJ
a.
100
90
80
70
60
50
40
30
20
10
0'
40
XHA»
(0.000124110° •103Ldn
(0.000143) 10°'08Ldn + (0.2) 100,03L
F.I. - 0.05 (Ld(J - 55)
60 70
Lgjn (DECIBELS)
H
u
<
a.
1
1.50 -!
<
1.25 |
1.00 6
<
0.75 F
FIGURE 7. COMPARISON OF CURVILINEAR FUNCTION
AND FRACTIONAL IMPACT LINEAR FUNCTION
53
-------
2.3.1 Human noise exposure criteria
The discussion of severe health effects in an environmental analysis
is meant to supplement the discussion of general adverse effects, not to
replace it at high noise levels. The general adverse effects - speech inter-
ference, sleep interruption, annoyance - continue to be present at high noise
levels, and in fact increase more rapidly at the higher noise levels. Equa-
tion 2 (or Table 3} can be used to summarize these effects for L
-------
is reasonable to use expected noise-induced hearing loss as a basis for
assessment of severe health effects.
A problem arises in specifying the noise measure to be used when quanti-
fying severe health effects. If hearing loss is used as the indicator, the
noise measure needs to reflect at-ear measuraaent to be valid. Further, hear-
ing loss is properly expressed as a function of Leq, rather than of	but
it will not usually seem warranted to calculate and draw noise contours for
more than one noise measure. The data to be discussed below predict noise-
induced permanent threshold shift (NIPTS) for 8-hour equivalent sound levels
(at-ear) starting at values of 75 dB. If the remaining 16 hours of the day
are spent in a noise environment of 70 dB Leq or lower, the at-ear 8-hour
equivalent sound level of 75 dl results in a 24-hour long Le^ of approximately
70 dB, at the ear. For many proposed projects (particularly actions where
assessment of hearing damage risk is of primary concern) it will be appropriate
to use one of these two measures.
It is also important to be able to identify the Ldn values at which it
is appropriate to look for severe health effects. Those persons who have the
greatest outdoor activity, including young children, retired persons living
in warm climates, and people in certain outdoor occupations, are clearly the
people of major concern when outdoor L,jn is considered. For outdoor expo-
sure, daytime levels are the important ones for establishing at-ear values.
The values of Ljn corresponding to an A-weighted equivalent sound level of
75 dB during daytime hours range between 73 and 81 dB. The lower value cor-
responds to a situation where the equivalent sound level during the night is
20 dB or more lower than that occurring during the day, whereas the higher
value corresponds to the situation when the equivalent sound level during the
night equals that occurring during the day. The most probable difference
55
-------
between the daytime and nighttime values of Leq is 4 dl, as shown for the
noise levels of interest in Fig. A-7 of the Levels document [2]. For this
day-night difference,	is three decibels above the daytime value of
Leq> that is, Ldn ¦ 78 dB. This value of 78 dB is considered to be the most
probable value of L^n to be found in real environments that have a daytime
Leq of 75 dB. (This estimation is based on that in reference 19, pp. 1-8 -
B-9.) However, due to the wide range of possible values, .it is recommended
that an outdoor L,jn of 75 dB be used as the threshold above which severe
health effects are investigated. This has the advantage of being an
value for which contours will already be mapped, and is therefore information
readily available.
Consequently, for areas with L<|a of 75 dl or above, it is important to
look for potential severe health effects. The way to do this is to estimate
the size of the population spending time outdoors, the length of time they
are outdoors, and the actual levels while they are outdoors. The last two of
these numbers can then be used to estimate the at-ear 24-hour Lgq for these
people (using the equation for Leq in Appendix A), As long as the outdoor
noise exposure exceeds 3 hours per day, the contribution of the indoor noise
environment may be neglected in computing the 24-hour LeCj. This conclusion
does not depend greatly on the actual noise attenuation provided by the house
so long as the attenuation is greater than 10 dB [19, p. 8-9].
There have been numerous studies conducted for the purpose of determining
the long term effect of noise on the hearing ability of an exposed population.
In particular, three studies [28,29,30] have provided reasonable predictive
models of the relationship between noise exposure and changes in the statisti-
cal distribution of hearing levels of the exposed population. These changes
are called Noise Induced Permanent Threshold Shifts (NIPTS). The results of
56
-------
these three studies were combined [311 and used in the EPA Levels document
[2, Table C-l], to provide a summary of the expected NIPTS that would occur
from a 40 year exposure beginning at an age of 20 years.
Inspection of Table C-l is the EPA Levels Document [2] shows that as the
average sound level of the exposure increases, there is a widening of the fre-
quencies affected by the exposure. As would be expected, the average of
500 Hz, 1000 Hz, 2000 Hz and 4000 Hz does not show a uniform constant, increase
in loss with a rising exposure level, but instead increases at an accelerated
pace with increasing average sound level. While use of the most sensitive
frequency is proper for the determination of an absolutely safe daily equiva-
lent sound level, assessment of the relative impact of exposure to higher
equivalent sound levels requires that all audiometric frequencies be con-
sidered, Therefore the average of 0.5 kHz, 1 kHz, 2 ktia, and 4 kHz is the
recommended measure. Since each of the four frequencies describes the center
of the preferred octave bands, there is no overlapping in octave bands as
would be the case if 3000 Hz was included.
Having selected a method to handle the question of frequency, the next
problem is time. One way to consider time is to select a point in time at
which the relative impact will be described. Selection of such a point is
somewhat arbitrary and not entirely meaningful. For instance one could argue
that it is more important to describe the effects of ncise when a person is
middle-age, and not when a person is 60 years old. An alternative approach
is to use the average NIPTS of the population during or ever a normal working
lifetime. Averaging NIPTS with respect to time avoids arbitrarily selecting
any one point in time and provides a realistic assessment of the overall
effect of noise on hearing on a large population, recognising that many indi-
viduals , because of differences in sensitivities and ages or lengths of
57
-------
exposure, may incur either more or less hearing loss than would be assessed
using this procedure.
A grand averaging of the NIPTS with respect to frequency (0,5 kHz, 1 kHz,
2 kHz, 4 kHz) and time CO to 40 years of exposure) and percentiles (0.1 to 0.9
percentiles) from references 2 and 31 is listed in Table 4. These NIPTS data
can be very well described by the formula:
Ave NIPTS ¦ (Leq(s) ~ 75)^/40 * ^eq(24) "70)^/40, Eqa. 10
where "Ave NIPTS" is the average NIPTS as discussed above. The slight dif-
ferences shown in Table 4 between equation 10 and the NIPTS data should be
considered insignificant, especially in view of the fact that the original
data were rounded to the nearest whole integer in any case.
TABLE 4
AVERAGE HEARING LOSS AS A FUNCTION OF 8-HOUR Leq
Leq(8)	Ave. Hearing Loss	&eq(8) ~ 75)^/40
dB	dB*	dB
75	0	0.0
80	1	0.625
85	3	2.5
90	6	5.625
95	10	10.0
Equation 10, then, is the criterion for estimating the potential severe
health effects due to a proposed project. For applications, it can be calcu-
lated directly, read from Table 5, or read from Figure 8. The outdoor day-
night sound level, L,jn, should be used only to identify potential problem
areas. Within those areas, an effort should be taade to estimate the actual
~Source: Table C-l of Levels Document [2], and Johnson [31]
58
-------
12
m 10
s.
oo
o
x
05
in
AC
H
H-
Z
ixf
Z
<
s
cc
UJ
CL
~
LU
U
D
~
Z
X
LU
OT
8
60
RECOMMENDED
HEARING LOSS
WEIGHTING
FUNCTION
(Leq{8) - 75)2
40
100
110
DAILY 8 HOUR EQUIVALENT SOUND LEVEL (cfB)
FIGURE 8. POTENTIAL HEARING DAMAGE RISK FOR DAILY
EXPOSURE TO 8 HOUR EQUIVALENT SOUND
LEVELS
59
-------
Table 5
CRITERION FUNCTION FOR SEVERE HEALTH EFFECTS
dB loss
75
76
77
78
79
80
81
82
83
84
85
90
95
70
71
72
73
74
75
76
77
78
79
80
85
90
0.025
0.100
0.225
0.400
0.625
0.900
1.225
1.600
2.025
2.500
5.625
10.0
0
exposure of groups of people. In any application, it should be remembered
that since this equation was developed from averaging the effects of noise
over frequency, time, and percentiles, it cannot estimate the effect on an
individual at one audiometric frequency at one point of time. This equation
should be used only to assess the average relative impact of exposure to
different equivalent sound levels.
It is also useful to look at individual susceptibility to noise induced
hearing loss, therefore, a user may wish to consider the NIPTS for the most
sensitive ten percent of the population after 40 years of exposure. This
information can be read from the 'Max. NIPTS 90th Percentile* curve of Figure
8.
2.3.2 Quantification of the impact
The first step in quantifying the impact is to construct the tables indi-
cating the number of people within decibel intervals. In many instances the
same tables setting out the extent of the general audible noise impact can
60
-------
serve for this noise range also, but if there are very many people exposed co
high levels, smaller contour intervals are recommended for tabulating the
severe health effects.
As with the general adverse effects, it is desirable to quantify the
exposure of individuals to different levels by a single number. A term simi-
lar to the level-weighted population may be calculated using the hearing loss
function (eqn. 10) identified in the previous section. This would result in
a hearing loss-weighted population, HWF, measured in terms of hearing loss,
expressed as person-decibels:
x
HWP - / P(Leq(8)) . H(Leq(8)) . d(Leq(8))	Eqn. 11
75
where P(Leq(g)) is the population distribution as a function of 8-hour Leq,
H(Leq(8)) is the weighting function given in equation 10 (and Figure 8 and
Table 5), and d(Leq(8)) is the differential change in 8-hour average sound
level. Replacing the integrals by summations of successive increments in
average sound level we have:
HWP - £Pi . H(Leq(8))i	Eqn. 12
where i indexes the successive increments in average sound level. If the
l*eq(24) measure is preferred for a particular application, summation would
start at 70 dB.
The disadvantage of the hearing-weighted population is that it is not
easily understood: the product of persons and decibels of hearing loss is
not an intuitively obvious concept. A more understandable indicator of
61
-------
severe health effects is the average potential hearing loss (PHL) which is
analogous to the noise impact index for general audible noise:
where the terns are as defined for equation 12, and Fgotal *-s equal to the
base population, which is normally the population exposed to levels above 75
dB. Care should be taken in defining the base population, however. If it is
to be used to compare alternatives, the same base population must be used for
all. Otherwise, the average hearing loss could be lowered by a project which
affected more people, and the indicator would not be a reliable measure of
impact. The simplest approach is to use as the base population the largest
total population subjected to severe health effects by any of the ilternatives
If this is done, PHL indicates the average hearing loss, in d cibels, for
those people subjected to severe health effects due to noise.
Again, the above equations may be replaced by a summation over successive
increments of day-night sound level. It is recommended that increments of
day-night sound level less than five decibels (i.e., preferably one or two
decibels) be used in calculating values of PHL.
Further, analogous to the assessment of general audible noise, the change
in hearing loss-weighted population is a useful descriptor for many assessment
purposes, as is the relative change in impact defined in Equation 8 with HWF
substituted for LWP.
2.4 Environmental degradation
Even in areas where no people are presently living, a significant in-
crease in noise over existing conditions may constitute a noise impact. The
PHL » *****		
ptotal	£P(Leq(8)>i
Eqn. 13
62
-------
environment may be degraded either because the increased noise affects wild-
life , or because it destroys the tranquility of a wilderness area to which
urban dwellers wish to go for an escape from city noise, or because it makes
the area unsuitable for future residential or other noise-sensitive develop-
ment. In each case, some of the quiet which is one of our national natural
resources is lost; the quality of the environment is lowered.
Unfortunately, there are no data available which express this reduction
in environmental quality as a function of noise level, or of the change in
noise level. Consequently, it is not possible to identify a special criterion
function for these areas, such as those identified in sections 2.2.1 and
2.3.1.* Instead, quantification of environmental degradation normally pro-
ceeds only as far as the tabulation of the extent of the impact. The only
modifications necessary for the standard tabulation (such as the example
Tables 6 through 9) is the likely deletion of the columns on residential and
employee populations, and a revision in the use of the special situations
column. Animal species which are particularly vulnerable and recreational
uses of the areas will be the principal kinds of special situations to be
listed. As a supplement to this numeric quantification, a word description of
the environmental impact should be provided in terras of the expected change
from the present conditions, paying particular attention to the special
situations. In some circumstances, it may be useful to reduce this tabulation
to a single number, for example for comparisons or trade-offs with other
planning criteria. In those cases, a "level-weighted area" can be calculated
^Reference 32 presents quantification methods for evaluating the noise impact
in recreational or wilderness areas. The evaluation criteria contained in
that report show a relationship between the detectability of sound sources
and the acceptability of those sounds in various recreational use areas.
This criteria is based on the experiences of U.S. Forest Service personnel.
63
-------
by using Che population weighting function of Table 3, which is the best
available indicator of relative impact.
Rural areas can be treated by the methods of either this section or sec-
tion 2.2. That is, the analysis can stop with the tabulation of impacts, oc
it can proceed to calculate the level-weighted population. The equation used
(equation 2b) shows some adverse response to general audible noise at levels
aa low as 45 dB (L^n). However, because the percentage responding adversely
is so small—less than 0.5 percent below 48 dB - and the number of people in
most rural areas is so low, the magnitude of the level-weighted population
will usually be so small as to be of little help in environmental assessment.
Although the single-number index can be used in such areas, it is not recom-
mended as strongly for them as it is for urban areas.
2.5 Treatment of temporary projects
The major simplification in the analysis for temporary projects has
already been mentioned (section 1.4.2): the fact that prediction of future
population in the affected area is unnecessary. For temporary projects
lasting more than one year, that is the only modification necessary.
For temporary projects, the same as for permanent noise environments,
the yearly day—night sound level should be used in computation of impact
indices. Impact assessment is done in the same manner as for permanent noise
environments by the use of tabulations and calculation of the sound level-
weighted population and noise impact index.
For temporary projects lasting less than a year, it is useful to compute
the level-weighted population for two situations:
(1) for the temporary noise environment as if it were permanent, but
also stating its actual duration; and
64
-------
(2) fdr the temporary noise environment in terns of its contribution
to the yearly day-night sound level.
For example, consider a population of 1000 experiencing a temporary day-night
sound level of 70 decibels for nine months due to a construction project,
after which the day-night sound level drops to 60 decibels on a long-term
basis. The following two situations would be described.
1.	During the nine-month construction period itself, the level-weighted
population is (0.245) (1000) ¦ 245 persons responding adversely to the noise.
2.	To calculate the effect of the construction activity on annual aver-
age impact requires calculation of the yearly day-night average sound level:
I	70	60
Ldn(y) " 10 log^g 12 (9 x 10*0) + (3 x 10*0) - 68,9 decibels Eqn. 14
The above equation is derived from equation A-5 in Appendix A. On the basis
of this L
-------
2.6 Practical example
Sample tables to demonstrate the approach discussed in this chapter have
been drawn up for a simple example, applying the basic principles presented in
these guidelines. The example is based on the proposed expansion of a highway
which runs through a suburban area, and is simplified to facilitate under-
standing of the suggested procedures. Details of the example are contained
in Appendix E, which also contains an additional practical example. This
section is intended primarily to provide samples of the appropriate tables.
It does not cover all possible types of problems for which these guidelines
are appropriate.
As discussed in section 2.2.2, a number of tables are usually helpful.
The first table documents affected areas (i.e., the base population and base
area) for future noise levels without the proposed project (Table 6); the
second deals with project noise alone (Table 7); and the third tabulates
effects for the project noise together with all other sources (Table 8).
The final table provides details of various special situations, which may
be particularly affected by noise (Table 9). At the bottom of Tables
6 to 8, several of the single number indexes are stated. By comparing the
single-number indexes presented in Tables 6 and 8, we see Chat the anticipated
change in impact is an increase of 111 more people responding strongly to the
adverse effects noise has on them. Likewise, the expected increase in
potentially severe health effects (Ldn >_ 75 dB) is in the range of 13 person-
decibels.
66
-------
TABLE 6
SAMPLE DATA PRESENTATION:
FUTURE NOISE LEVELS WITHOUT PROPOSED PROJECT
Yearly Ldn
Resident ial
Population
Industrial/
Commercial
Employees
Total
Land Area
(sq km)
Resident ial
Land Area
(sq km)
Industrial/
Commercial
Land Area
(sq km)
Special
Situat ions
(See Table)
>85
0
0
0
0
0
-
80-85
0
10
0.0156
0
0.0156
-
75-80
0
40
0.0469
0
0.0469
-
70-75
0
130
0.0625
0
0.0625
-
65-70
833
470
0.3125
0.1875
0.1250
- •
60-65
1389
2840
0.8542
0.3125
0.5417
8
55-60
2778
510
0.7u<*3
0.6250
0.0833
1,2,3,4,5,6,7
50-55
0
0
0
0
0
-
45-50
0
0
0
0
0
-

5,000
4,000
2.0
1.125
0.875

Level Weighted Population
Noise Impact Index (Nil) =
Hearing-loss Weighted Popu
(LWP) = 501 peopl
0.10
lation (HWP) = 0
e



-------
TABLE 7
SAMPLE DATA PRESENTATION:
FUTURE NOISE LEVELS OF PROJECT ALONE
Yearly Ldn
Resident ial
Population
Industrial/
Commercial
Employees
Total
Land Area
(sq km)
Residential
Land Area
(sq km)
Industrial/
Commercial
Land Area
(sq km)
Special
Situations
(See Table)
>85
80-85
75-80
70-75
65-70
60-65
55-60
50-55
45-50
0
0
83
150
350
717
1200
833
1667
0
0
140
240
370
800
1500
380
570
0
0
0.050
0.090
0.160
0.340
0.610
0.250
0.500
0
0
0.01875
0.03375
0.07875
0.16125
0.27000
0.18750
0.37500
0
0
0.03125
0.05625
0.08125
0.17875
0.34000
0.06250
0.12500
1.2
3.6
4.7
5
5,000
4,000
2.000
1.12500
0.8750
Level Weighted Population (LWP) = 362 people
Noise Impact Index (Nil) = 0.07
Hearing-Loss Weighted Population (HWP) = 13 person-decibels
Average Potential Hearing Loss (PHL) - 0.16 dB per person for 83 people
-------
TABLE 8
SAMPLE DATA PRESENTATION:
FUTURE LEVELS FROM ALL SOURCES COMBINED
Industrial/
Industrial/ Total Residential Commercial	Special
Residential Commercial Land Area Land Area Land Area	Situations
Yearly Ldn
Populat ion
Employees
(sq .cm;
(sq km)
(sq km)
(See Table)
>85
0
0
0
0
0
-
80-85
0
10
0.0160
0
0.0160
-
75-30
83
75
0.0969
0.01875
0.07815
-
70-75
150
240
0.1350
0.03375
0.10125
8
65-70
1278
640
0.44875
0.28750
0.16125
-
60-65
1128
2535
0.6971
0.25375
0.44335
1.2
55-60
2361
500
0.60625
0.53125
0.0750
3,4,5,6,7
50-55
0
0
0
0
0

45-50
0
0
0
0
0

5,000	4,000	2.000	1.12500	0.8750
Level Weighted Population (LWP) = 612 people
Noise Impact Index (Nil) = 0.12
Hearing-Loss Weighted Population (HWP) " 13 person-decibels
Average Potential Hearing Loss (PHL) ¦ 0.16 dB per person for 83 people
-------
TABLE 9
SAMPLE DATA PRESENTATION;
SPECIAL SITUATIONS
Average Population
Day	Night
Area (sq km)
Comments
1.	School	300
2.	Playground	40
3.	Park	30
4.	Church	63
5.	Nursing Hone	200
6.	School	1000
7.	Library	25
8.	School x	500
0
0
0
200
150
5
Night Classes
70
-------
CHAPTER 3
SPECIAL NOISES
\
Hoc all noises can be adequately evaluated by average A-weighted sound
levels. Examples of the special noises which require other measurement sys-
terns are the following: (1) infrasound, in the frequency range of 0.1 to
20 Hz; (2) ultrasound, frequency range above 20 kHz; (3) certain types of
impulse noises such as sonic booms and blasts; and (4) sounds that convey
more information than random noise sources with comparable average sound
levels, such as voices, warning signals, or barking dogs. This chapter con-
tains a section discussing each of these four special noises. For the first
three, the section discusses measurement, screening levels, and human effects.
For the fourth, the section merely provides a brief description of the nature
of the problem and of how it might be treated in a noise impact analysis,
3.1 High-energy impulse noise
The assessment of impulse noise presents unusual problems. In many cases
the appropriate techniques and measures are applicable only to particular sit-
uations. (For example, with respect to blast noise, damage to certain types
of buildings can be predicted in terns of non-acoustic parameters, such as
effective distance and the amount of explosive charge.) Moreover, the sig-
nificance of the noise impact cannot always be quantified for the same effects
suggested for general audible noises. Whereas low-level impulse noise is
accounted for as part of normal general audible noise, high-energy impulses
require additional measurements for impact assessment. In many situations an
individual interpretation of the criteria is required.
71
-------
At present, high-energy impulse noise comes primarily from sonic booms,
blasting operations, or artillery fire. Some limited community response data
for sonic booms and artillery fire are available [33, 34], Noise measurement
instrumentation at the time of the sonic boom study (1965) was not as sophis-
ticated as it is now, so the physical measures from that study (peak overpres-
sure in pounds per square foot) need to be converted to more recently devel-
oped measures. Consequently, the methods presented in this section need to
be verified with more data, some of which is being collected at the time of
this writing. The methods presented here are based on the only available data
[5], and should be applied with some caution.
3.1.1 Description of high-energy impulse noise
Day-night sound level is the primary descriptor for environmental noise.
High-energy impulse sounds, such as those produced by sonic booms, quarry
blasts, or artillery fire, in addition to the high-level audible sound, can
excite noticeable vibration of buildings and other structures. These induced
vibrations — caused by airborne sound or transmitted through the ground
or structures — may generate additional annoyance beyond that due to simple
audibility of the impulse, because of "house rattling" and "startle," as well
as because of additional contributions to interference with speech or sleep.
The annoyance data which are used in the next section to summarize community
response to impulse noise are based on the annoyance caused by house rattle.
It has been general practice in the past to describe such high-energy
impulse sounds in terms of the peak sound pressure level over a wide fre-
quency band. While the peak pressure may be satisfactory for assessment of
impulses in a restricted range of peak pressures and durations, it is not
sufficient as a general descriptor for use in measurement or prediction of
72
-------
the combined environmental effects of impulses having substantially different
pressure-time characteristics. Use of the peak pressure is also unwieldly
or misleading when a succession of impulses, sometimes overlapping, must be
evaluated.
The noise measure recommended in these guidelines for assessing the
environmental impact of high-energy impulse noise is similar to the measure
used for general audible noise. This is the Oveighted day-night sound level,
symbolized as Lpdn* The l«cdn« *n turn> may be derived from individual
impulse noise events described in terms of a C-weighted sound exposure level,
1*SC*
There are two reasons for using a C-weighting. First, it does not dis-
count the low frequency components which are a major part of impulse noise and
of vibration, as the A-weighting network does. Second, subjective estimates
of impulsive noise magnitude conform with magnitude estimates of other noises
when the high-energy impulsive noise is measured by C-weighting and" the other
noises are measured by A-weighting [35]. In general, C-weighting has been
found to closely relate to average human response to high-energy impulse
noise {36].*
The use of sound exposure level is recommended to facilitate combination
of data when more than one impulse noise event occurs per day, as is usually
the case. Further, it is consistent with subjective evaluations of sonic
booms where duration of the signal influences subjective response [38],
The assessment procedures suggested in this section should be used for
impulse sounds that have daytime C-weighted sound exposure levels greater than
For most situations, C-weighted sound exposure levels are adequate for
assessing the impact of high-energy impulsive noise. However, for very low
frequency noise events, such as confined blasts, C-weighted sound exposure
level may not be as good as various lower frequency measures [37].
73
-------
about 80 dB. This corresponds to unweighted peak sound pressure levels for
sonic booms and confined mining blasts greater than about 106 dB, which
appears to be the threshold of adverse community response on the basis of
the data on sonic booms. This in turn corresponds to unweighted peak sound
pressure for unconfined surface explosions and artillery fire of about 100 dB.
At night, the threshold of response should be reduced to a C-weighted sound
exposure level of 70 dB (corresponding to unweighted peak sound pressure
levels of 96 dB and 90 dB for sonic booms and artillery fire, respectively),
because of the decreased acceptability of nighttime impulsive exposures [33,
p. 150]. Impulse events with lower levels than described above are assumed
to elicit normal auditory responses and are assumed for most situations to be
described adequately by L^n. For very high level impulses with unweighted
peak sound pressure levels greater than 140 dB, assessment criteria based on
actual physic logical or structural damage should also be applied. In addi-
tion, the efSects of groundborne vibration should be assessed (Chapter 4).
In most cases where impulse noise needs to be considered, the task for
the noise impact analysis is to predict or estimate in advance what the levels
of impulse noi33 will be. With rare exceptions (e.g., reference 39), there
are no reliable predictive techniques other than using a measurement of a
similar event occurring elsewhere. When the only data available are expressed
as peak sound pressure, useful approximations can be based on indications that
Lg£ is roughly 26 dB lower than the peak sound pressure level for both booms
[40] and confined blasts, and 20 dl lower for unconfined blast noise and
artillery fire [41, Fig. 29]. In those cases where it is possible to conduct
measurements of a similar event elsewhere, it is important to be able to
distinguish impulse noise (such as 3onic boom) from other high-energy noise
events (such as jet aircraft flyovers). A useful rule of thumb to aid in
74
-------
making such a distinction is that for an impulse noise the maximum C-weighted
sound exposure level in any 2-second time period is 10 dl greater than the
C-weighted sound exposure level in any contiguous 2-second period of the
event.
3.1.2 Human noise exposure effects of high-energy impulse noise
The Oklahoma City sonic boom study [33] and the artillery fire study
[34] form the primary bases for the procedure proposed for assessment of the
effects of high-energy impulse sounds. In the sonic boom study [33], eight
supersonic overflights were performed daily for six months. Altitudes and
airspeeds were selected to obtain three different nominal overpressures, on
an increasing basis, during the tests. Personal interviews of respondents
were made during three time periods that corresponded to the three different
nominal overpressures. Interviews were conducted at three different distances
from the ground projection of the flight path to obtain different exposures
for each of the three boom levels.
The questionnaire structure and response scaling used in the sonic boom
social survey are such that direct comparison with other surveys is difficult.
The responses to a question on the degree of annoyance due to "house rattles"
caused by the booms is used here as the primary measure to quantify community
response. The category "serious" annoyance is considered to be most compar-
able to the highly annoyed response used (in section 2.2.1) to summarize the
adverse effects of general audible noise. It should be noted that the percent
of respondents reportings serious annoyance at different boom levels was not
a percentage of the total population sample, but only of that fraction of the
sample that believed it appropriate to complain about governmental actions.
This fraction is of the order of 60 percent. To compare these responses to
75
-------
the total populations used in other surveys, an adjustment for .the total
population was made in the current analysis.
The noise measurements in the sonic boom study were collected in terms
of nominal peak overpressures. Conversion of nominal overpressures to C-
weighted sound exposure levels were made using the average difference of 26
decibels between peak overpressure and C-weighted sound exposure level. The
resulting values were then used to compute I«cdn ^or c^e ®ight daytime sonic
boons, using the approximation:
I*Cdn * 1«SC + 10 log (Njj + 10 Nn) - 49.4	Eqn. 16
where and Nn represent the number of impulse events	during the day and
night, respectively. Thus for eight sonic booms per day, equation 16 reduces
to:
LCdn " I-SC ~ ^°*5	2qn. 17
The resulting data for the percent highly annoyed at the computed C-weighted
day-night sound level values are plotted as filled-in squares in Figure 9.
In the artillery fire study [34], groups of residents were interviewed at
nine sites in the vicinity of an Army base where extensive artillery firing
training takes place. Six of the sites that were off-base are considered
here. Noise monitoring on a 24-hour basis took place at 17 locations for an
average of approximately 25 days per site. These measured average sound
levels in conjunction with computer based predictive models were used to ob-
tain annual average C-weighted day-night average sound levels for artillery
noise associated with the environments in which the survey respondents lived.
The social survey used scales similar to other recent surveys. The percent
76
-------
of respondents reporting high annoyance are plotted as filled-in circles on
Figure 9.
Using annoyance data from both the Oklahoma City sonic boom study and
the artillery fire study, a function is plotted in Figure 9 which shows a
reasonably good fit of projected high annoyance against C-weighted day-night
sound levels. Over the range of data available, the function illustrated
in Figure 9 provides a reasonably good prediction of the percentage of the
population who can be expected to be highly annoyed at given exposures to
high-energy impulse noise. Consequently, it is proposed to use the function
shown in Figure 9 and presented in equation 18 below* for the assessment of
high-energy impulse noise, despite the fact that such applications may need
to extrapolate beyond existing data.
	100	
~ 1 + e(11.17 - 0.153 Lcdn)	Eqn- 18
Quantification of adverse human response anticipated from high-energy
impulse noise is performed is. the same manner as for general audible noise
(Section 2.2.2). The appropriate weighting function describing the population
exposed to high-energy impulses who are highly annoyed with the noise may be
computed from equation 18, or read from Figure 9 or Table 10. Level-weighted
population may then be computed from equation 6. Likewise, Noise Impact
Index and Relative Change in Population may be calculated from equations 7
and 8, respectively.
In many situations, both impulse noise (measured in Lq
-------
Army Artillery
Sonic loom
%HA - t + # (11.17 - 0.153 LC{Jr)>
1 l-Cdn 'For 8 Events I
FIGURE 9- RECOMMENDED RELATIONSHIP FOR PREDICTING
COMMUNITY RESPONSE TO HIGH ENERGY
IMPULSIVE SOUNDS (Source : Reference 5)
Lata, ¦ L„ ~ 10fef m* 10Nn».49.4
2fl ftof **»*¦ booms and conflrwd blasts^
Lgl * Lp^-20 Cfcw ¦rtilitrv'Hr* wd ynowrft**! hiwort
78
-------
TABLE 10
VALUES OF WEIGHTING FUNCTION FOR HIGH ENERGY IMPULSE NOISE
[W(Lcdn) - (0.01)% HA]
LCdt
W(Lcdn)
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
0.014
0.016
0.018
0.021
0.025
0.029
0.033
0.039
0.045
0.052
0.060
0.069
0.080
0.091
0.105
0.120
0.137
.157
,178
0.201
0.227
0.255
,285
.317
0.351
0.387
0.424
0.462
0.500
0.538
0.576
0.
0.
0.
0.
79
-------
somehow Co combine the results to obtain a total number of people affected
by all aspects of the noise. An assessment of the overall noise environment,
combining the effects of high-energy impulse sounds and of general audible
noise, can be made by equating the degree of annoyance expected from the two
types of noise sources. Using Figures 4 and 9, then, it is possible to
identify a specific C-weighted L^n which causes as much annoyance as an
A-weighted day-night sound level. For example, an L^n 65 dB is expected
to result in 23 percent of the exposed population being highly annoyed by the
noise (Figure 9). This same level of annoyance is reached at an A-weighted
day-night sound level of 69 dl (Figure 4). Thus the	may be converted
to Ldn via equal annoyance (Table 11). This converted L^n is added, log-
arithmically, to the general audible noise already measured in terms of Ldn,
and the resulting composite noise level is used for assessment of the overall
noise environment, using Figure 4 and Table 3 as necessary. This procedure is
performed in order to avoid the double-counting of affected people which could
result if they were tallied separately for impulse noise and for general
audible noise.
3.1.3 Structural damage criteria for impulse noise
It is normally considered that the most sensitive parts of a structure to
airborne noise or overpressure are the structure's windows, although in some
cases it may be plastered walls or ceilings. Such noise or large pressure
waves also introduce building vibration in addition to that due to ground
t xon * Thus the effects of airborne sound on structures may need to be
evaluated in terms of vibration criteria as well as in terms of criteria based
on peak overpressure. For most airborne sound, however, evaluation of the
peak overpressure is sufficient to determine the threshold of possible damage.
80
-------
TABLE 11
CONVERSION OF LC(Jn TO Ldn VIA EQUAL ANNOYANCE
LCda
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
Z Highly Annoyed
1
2
2
2
3
3
3
4
4
5
6
7
8
9
10
12
14
16
18
20
23
25
28
32
35
39
42
46
50
54
58
45
49
49
49
52
52
52
54
54
56
57
58
59
60
61
63
64
65
67
68
69
70
72
73
74
76
77
78
79
80
81
81
-------
On the other hand, for some types of underground blasting and when the build-
ing is close to the blast site, the vibration is transmitted essentially
through the ground. In this case the vibration inside the house must be
predicted and evaluated according to the vibration criteria (Chap. 4). This
subsection describes structural damage criteria for three kinds of impulse
noise: blast noise; sonic boom; and artillery fire. A brief paragraph is
appended relating to structural damage from continuous sounds.
For blast noises, the probability of broken windowpanes should be esti-
mated. Empirical formulas given belov allow an estimate of "safe" distances
from the blast, beyond which window damage is negligible. These formulas
include sufficient safety factors to account for the negative influence of
such variables as wind direction, atmospheric temperature gradients, and win-
do vpane shape and size. These formulas are newly proposed and are somewhat
tentative [42]. They are suggested here essentially as screening tools; if
these equations suggest there will be no structural problems for a particular
project, the impact analysis needs to proceed no further. If these formulas
suggest a potential impact of blast noise on structures, then the analyst (or
blasting engineer) should undertake a more detailed analysis which involves
explicit consideration of the variables covered by a safety factor in these
formulas. It should be noted that the relationships expressed in these for-
mulas may not be applicable at distances of less than 1 km between the blast-
ing activity and the nearest residence depending upon situational factors.
For these cases, direct air blast monitoring is recommended to assure that
excessive noise levels are not reached.
For surface explosions, window breakage in residential type structures is
expected to be negligible (less than 50 percent probability of even one broken
82
-------
pane) if the charge per delay equivalent weight* of high explosive (WHE) in
kilograms is less than that specified by the more appropriate of the following
two conditions:
(1)	If the population is non-uniforaly distributed, but is clustered,
then each population cluster, including the nearest residence,
should be checked. The amount of WHE for any cluster should be
less than 328 R^/N where R is the distance in kilometers from the
explosion to the center of a cluster of residences and N is the
number of people residing in that cluster with the provison that N
must always be at least 4 (assumed number of people per house),
(2)	If the population is reasonably uniformly distributed, then the
amount of WHE should be less than 40 R^, where R is the distance
in kilometers to the nearest residence.
The use of these formulas requires some judgment as to what constitutes a pop-
ulation cluster and what constitutes a reasonably uniform distribution. In
some cases, both formulas might be checked and the one that predicts the least
allowable amount of WHE used.
For explosives buried deeper than 1.4 meter per (Kg)1/3, the peak
amplitude will be attenuated by at least a factor of 5**. For such under-
ground explosions the preceding formulas need to be adjusted as follows:
(1)	Population clusters - the amount of WHE should be less than 26430
R3/N.
(2)	Uniformly distributed population - the amount of WHE should be
less than than 3200 R^.
*Weight per detonation where each detonation is delayed to go off in a
predetermined sequence (usually within a fraction of one second) for each
event. The duration of the total event is normally less than one second.
**The factor of 5 is based on effects at large distances. At short distances
this may range to a factor of 15 or even higher.
83
-------
For explosive charges greater than those determined by the above formu-
las, the peak overpressure should be predicted and the number of broken win-
dows estimated. The statistical estimator (Q) for the number of "average
typical" panes broken is:
Q - 1.56 x 10"10 N(PK*)2-78	Eqn. 17
where H ¦ number of people exposed (assuming 19 panes per person) and PK* is
the peak-to—peak amplitude of the pressure variation (in pascals) at ground
level. The conversion between the peak free air pressure (Ap) and PK* is
given by the relation;
PI* ¦ 2.7 dP	-	Eqn. 18
However, the peak pressure may be amplified by a factor of 5 as the result of
atmospheric refraction, ducting, and focusing; therefore, in the "worst case"
condition the number of broken panes, Q, may be multiplied by a factor as high
as (5)2.78 or gg t0 obtain Qmax* *n addition, for peak pressures (A?)
above 140 dB (200 Pa), structural damage other than window damage may occur.
Measurement or prediction of vibration should be accomplished.
For sonic booms, mining blasts,and artillery fire, the amount of window
damage can be estimated by calculating Q and Qnax for the expected peak
pressure, as discussed for blasts. These formulas, however, should be used
only for peak pressure levels above 130 dB. Above 140 dB, structural damage
should also be assessed by prediction or measurement of vibration levels in
the exposed structures.
For continuous sounds above sound pressure levels of 130 dB, there is
the possibility of structural damage due to excitation of structural reso-
nances for infrasound, as well as low and medium frequency sound. While
84
-------
certain frequencies (such as 30 Hz for window breakage) might be of more
concern than other frequencies, one nay conservatively consider all sound
lasting more than 1 sec above a sound pressure level of 130 dB (1 Hz to 1000
Hz) as potentially damaging to structures.
3.2 Infrasound
3.2.1	Description of infrasound
Infrasound is defined as sound in the frequency range below about 20 Hz.
The measurement of infrasound should be made with instrumentation having a
flat frequency response (+3 dB) from 0.1 Iz to 1000 Hz. The reason for the
extended measurement range is that in evaluating a noise that is composed of
both infrasound and higher frequency sound, the higher frequency sound must
also be measured for proper assessment of the infrasound, because sounds above
20 Hz can mask the infrasonic sounds.
Although blasting operations cause infrasound as well as impulse noise
and vibration, it is not intended that all of these analyses be conducted.
Among other considerations, the necessary instrumentation is different for
each of these special noises. For blasting, an impulse noise evaluation is
adequate, covering both human and structural effects. Because infrasound can
be related to vibration, the vibration analysis (Chap. 4) also helps reduce
any need for a special infrasound analysis.
3.2.2	Human noise exposure effects of infrasound
On the basis of a summary of infrasound effects (figure 10), compiled
from the Levels Document [2] and more recent work [43, 44], it is suggested
that for exposures of less than 1 minute the maximum sound pressure level
should be below the following values:
85
-------
CURVE A
SOUND PRESSURE LEVEL BELOW WHICH
INFRASOUND IS NOT EXPECTED TO
PRODUCE ANY ADVERSE PHYSIOLOGICAL
EFFECTS
iu
CD 120
t/i
CURVE B1
CURVE B2
ESTIMATED
LOUDNESS OF
45PHON
ANNOYANCE THRESHOLD
DUE TO BUILDING STRUCTURE
VIBRATION OR MIDDLE
EAR PRESSURE
CURVE C
RANGE OF HEARING THRESHOLD
0.1 HZ 0.2	0.5 1HZ 2	5 10HZ 20HZ
«
FREQUENCY (HZ)
FIGURE 10. INFRASOUND CRITERIA
86
-------
0.1 Hz to 5 Hz . . . 120 dB
5 Hz to 20 Hz . . . 120 dB - 30 log j	Eqn. 19
where f is the dominant frequency. For exposures longer than 1 minute and
less than 100 minutes, the levels should be reduced by (10 log t) dB where t
is tine of exposure in minutes. Exposure longer than 100 minutes should use
the 100 minute limits. In other words, exposures 20 dB less than the one-
minute criterion should be regarded as having no impact, regardless of expo-
sure time, the 100-minute criterion basically insures that the infrasound is
inaudible. These levels serve essentially as screening levels. As long as
they are not exceeded, infrasound does not need to be included in the noise
analysis.
For evaluating the impact, if this screening criterion is exceeded, a
single-numbtr index is not suitable. Instead, the impact should be qualita-
tively described; the effects that might occur at different sound levels are
given in Fgure 10. Any assessment of the effects beyond those in Figure 10
is not contained in these guidelines and will require further research and
investigation.
3.3 Ultrasound
3.3.1 Description of ultrasound
Ultrasound is defined as sound at frequencies between 20 kHz and 100
kHz. Seldom is ultrasound an environmental problem and, unless the level
is expected to exceed 105 dB, it can be ignored in an environmental noise
analysis.
Measurement of ultrasound should be accomplished by instrumentation with
flat response (_+ 3 dB) from 10 kHz to 100 kHz.
87
-------
3.3,2 Human effects of ultrasound
Ultrasound noise levels below 105 dB (frequencies above 20 kHz) are
considered to have no significant impact on people. Noise levels above 105
decibels should be reported in the analysis and individually evaluated based
on specific research studies. In particular, studies of effects on animals
may be important. No further quantification of the environmental impact of
ultrasound is recommended. Rarely is ultrasound (except for some occupational
situations, e.g., ultrasonic cleaners) an environmental problem of practical
interest. Evaluation of ultrasound exposure above 105 dB requires additional
investigation and research.
3.4 Noises with information content
Some general audible noises are also more annoying than their level alone
would indicate, due in part to their information content or clear detectabil-
ity. Examples include barking dogs and back-up alarms, but the primary prob-
lem is voice communication (live, amplified or recorded) that crosses residen-
tial boundaries at high levels. There is no formal method for assessing the
impact of such sounds; each case must be assessed on its particular merits.
It is recommended, however, that the analyst mentions how, as a result of the
proposed action, the intrusion of understandable voices into some area might
cause loss of privacy and consequent undesirable effects. The actual content
of the typical messages or words might be stated along with the number of
people that are impacted.
88
-------
CHAPTER 4
VIBRATION
This chapter contains procedures for evaluating the impact of vibration
on man. While the main reason for their inclusion here is to account for v
vibration generated by airborne noise, the impact of certain types of vibra-
tion can be assessed whether the transmission paths are airborne or structure-
borne. The two sections of this chapter deal with the human effects of vibra-
tion (Section 4.1) and the structural effects of vibration (Section 4.2).
The material in the first section is based on an approved ISO standard
and its proposed amendments [45], and its United States Counterpart [46, 47],
These are summarized in Appendix 0, to provide the necessary background to
follow the recommendations in section 4.1. The recommendations in section 4.2
are based on consideration of that material and data contained in Bureau of
Mines Bulletin 656 [48] and Report 8507 [49].
4.1 Human effects of vibration
Vibration of structures may be due to airborne acoustical waves or solid-
borne vibration. Most problems caused by airborne impulse noise, when build-
ing vibrations are caused as a side effect of the primary auditory stimulus,
should be accounted for by the procedures of section 3.1. Nevertheless, at
certain times it may be necessary to assess separately the vibration caused by
such sources. Groundborne vibration which is quite likely to accompany some
mining, construction, and other industrial activities usually requires special
evaluation. A method to evaluate human response to vibration inside buildings
is presented which should be used to evaluate the impact of such activities.
The method applies to the frequency range between 1 Hz and 80 Hz.
89
-------
4.1.1 Description of building vibration
In those cases where vibration impact needs to be considered, the task
for the noise impact analysis is to predict or estimate in advance what the
levels of vibration will be. However, there are no reliable predictive
techniques to estimate magnitude of vibration. Therefore, it is suggested
that, if possible, a similar event be measured elsewhere.
For continuous vibration environments, rms acceleration should be mea-
sured along three orthogonal axes, one axis of which is normal to the surface
being measured. The acceleration should be weighted to account for the
dependence of human reaction on frequency by use of a low pass filter with a
corner frequency of 5.6 Hz (Figure 11). This accounts for the fact that human
sensitivity to acceleration decreases over the frequency range under consi-
deration; above 10 Hz this decrease is approximately proportional to fre-
quency. The assessment of the impact should be against greatest acceleration
on any of the three axes used.
For building measurements to be appropriate for the criteria of the
next subsection, the measurements should be taken on the floor at a point that
has the maximum amplitude of all the reasonable points of entry of the vibra-
tion to the human occupants. Normally this point may be assumed to be at the
mid-span or center of a room.
For impulsive shock the measurement should be the same as for the contin-
uous vibration measurement, except that the peak acceleration, not the rms
value, should be used. The duration for impulsive shock excitation will be
determined by either the time the acceleration of an event exceeds 0.01
m/sec^ or by the time the acceleration is within one-tenth of the peak
value. Whichever gives the shorter duration should be used.
90
-------
ATTENUATION (dB) - 20 log /l + 
FIGURE 11. WEIGHTING CHARACTERISTIC FOR BUILDING
VIBRATION IN TERMS OF HUMAN RESPONSE
FOR THE FREQUENCY RANGE 1 TO 80 Hz.
Nou: Electrical ixtwork for low frequency cutoff balow
t Hz and high frequency cutoff abowa SO Hz not yat
itandardizad.
91
-------
i
4.1.2 Human vibration exposure criteria
Threshold levels are presented in Table 12 for most types of structures.
Hot all types of buildings are classified, but common sense should suggest
the most appropriate classification.
The overall vibration that will not cause an adverse impact* for any
condition and time period corresponds to ras acceleration values below 3.6 x
10"^ m/s^, evaluated by means of the weighting described in Figure 11.
For hospital operating areas and other such critical areas, no higher levels
should be permitted without analysis and justification of the acceptability of
such levels.
TABLE 12
BASIC THRESHOLD ACCELERATION VALUES* FOR ACCEPTABLE VIBRATION ENVIRONMENTS
Continuous or	Impulsive Shock
Type of Place
Time
of Day
Intermittent rms
Acceleration (m/sec^)
Excitation Peak
Acceleration (m/sec2)
Hospital Operating
Rooms and Other Such
Critical Areas
Day
Night
0.0036
0.0036
0.005
0.005
Residential
Day
0.072
0.1
H
0.01

Night
c
0.005
Office
Anytime
0.14
t
0.2
N
Factory and Workshop
Anytime
0.28
t
0.4
N
~Weighted as shown in Figure 11.
t = duration seconds of vibration, for durations greater than 100 sec, use
t as 100 sec.
S 1 is the number of discrete shock excitations that are one sec or leS3 in
duration. For more than 100 excitations, use N ¦ 100.
Daytime is 7 am to 10 pm. Nighttime is 10 pm to 7 am
~Insofar as structural damage is concerned, special caution is needed below
4 Hz [49].
92
-------
For residential and other similar areas, continuous acceleration of
greater values are normally expected to cause virtually no complaints (less
than 1 percent). Even greater acceleration values could be permitted for
shorter times during the daytime (0700 to 2200 hours), as indicated by Table
12 and by Figure 12, These also indicate that the maximum value of the
impulsive shock excitation that is expected to cause virtually no complaints
can be raised, dependent on the number of such impulses during the daytime.
For residential areas or other areas where people sleep, the nighttime peak
acceleration should be less than 0,01 m/see^ at any time and the continuous
rms acceleration should be below 0.005 m/sec^ if no complaints are to occur.
No differentiation is made as to the types of residential areas, i.e., city
center, urban or rural.
For office type spaces, the threshold at which no adverse effects occur
is twice the daytime residential rms or peak value. No distinction is made
between daytime and nighttime exposure.
For factory and similar type spaces, the threshold at which no effects
occur is 4 times the daytime residential values. Ho distinction is made
between daytime and nighttime exposure.
Offices and workplaces may in many cases require vibration levels as
low as residential areas if any adverse reactions are to be avoided. In
certain critical areas, such as operating rooms and laboratories and possibly
research laboratories, standards rooms, tool rooms and the like, even lower
vibration exposures levels may be required than indicated by Table 12.
The acceleration values that are specified to cause less than 1 percent
complaints are near or at the perception threshold level of vibration during
normal activity and should serve as a realistic threshold of any adverse
reaction to the vibration. The percentage of complaints likely to occur
93
-------
vO
4>-
2.0
1.0
0.5
I Threshold of risk of damage to normal dwelling-houses with plastered
ceiling and walls
'n ^ Threshold of risk of damage to sensitive structures
X
CN
O
Ui
(/>
CO
cc
Ui
h
Ul
S
z
o
h-
<
CC
Ui
_l
Ui
o
o
<

ISO PROPOSAL
3 IMPULSES/DAY
\
Daytime peak impulses (complaints <20%)
Daytime rms (complaints <20%)
Daytime peak impulses (complaints<1%)
Daytime rms (complaints<1%)
Nighttime rms (complaints <1%)
10'
10'
10J
10
(HOURS)
1m/sec2
0.5m/i«c
0.01 m/sec^ _
0.0072m/secz
0.005m/sec^
10®
J SEC OR NR. OF
24
IMPULSES
NUMBER OF IMPULSES PER DAY OR EXPOSURE TIME
FIGURE 12. VIBRATION CRITERIA FOR RESIDENTIAL AREAS
-------
for higher levels of vibration are shown in Figure 13, which summarizes
the complaint history from the Salmon Nuclear Event [48], For a single
event the number of complaints for residential areas varies roughly as 10 log
K (for peak acceleration range of 0-1 m/sec^ to 1.0 m/sec^), where K is
the ratio of the observed acceleration to 0.1 m/sec^,
4.1.3 Quantification of the impact
There is a lack of data related to the assessment of the severity of
the impact that results if the vibration guidelines proposed in this section
are exceeded. It is recommended that the number of people exposed to vibra-
tion levels above the "no complaint" value (Table 12) be estimated. For a
specific action, therefore, contours of the appropriate "no complaint" accel-
eration values as determined by Table 12 should be predicted or measured.
For example, if an action causes a steady vibration that lasts a total of
25 seconds a day (during daytime hours), the contour of 0.014 m/sec^ should
be evaluated (0.072/ 25 - 0.014).
In addition to the mapping and tabulation of the impact, which cover
sensitive non-residential as well as residential buildings, single-number
indexes can be calculated which are similar to those suggested for general
audible noise (the level-weighted population and hearing-weighted population).
These indexes are based on the relationship for the percent complaining,
documented in Figure 13. It is suggested that this concept be tentatively
broadened to apply the vibration exposure to more than one impulse or to
intermittent/continuous exposures by using the ratio (k) of the actual accel-
eration to the recommended "no complaint" acceleration value. A term for the
impact of vibration on residential areas can then be defined by using a vibra-
tion weighting function. This function is described by:
95
-------
10	15
PERCENTAGE COMPLAINTS
Figure-13. Percentage of Population Complaining as a Function of Peak Acceleration (Source: Reference 48)
96
-------
V(k) - 20 log k
Eqn. 20
where k is Che ratio of the actual acceleration to the recommended "no con**
plaint" acceleration values listed in Table 12 for a specified time period,
and where k is limited to values from 1 to 20.
This function can be used to calculate a descriptor of the total vibra-
tion impact of a project, by multiplying the number of people exposed to each
vibration condition by the vibration weighting function for that condition,
and then finding the sum of these products. This Vibration-Weighted Popula-
tion (VWP) is defined as:
where V(k) is the vibration weighting function described above, F(k)	is the
population distribution function, and dk is the differential change in k. An
index, similar to the Noise Impact Index, but applied to vibration, is	called
the Vibration Impact Index (VII) and is calculated as:
where the denominator is based on the alternative affecting the largest num-
ber of people. In other words, the base population for calculating the vibra-
tion impact index needs to be constant across alternatives for the number to
be meaningful. Given that restriction, then changes in VWP and VII can both
be used to evaluate various alternatives and actions with respect to vibra-
tion. The change can also be discussed by listing the expected effects at the
nearest residence.
k
Eqn. 21
k
f P(k) V(k) dk
VII - -	
k
Eqn. 22
f P(k) dk
1
97
-------
4.2 Structural effects of vibracion
A structural vibration velocity of 2 in/sec has commonly been used
as the safe limit, and certainly vibrations above this value will have a
very adverse environmental impact. Note that, except for frequencies below
3 Hz, if the acceleration measured with the weighting network of Figure 11
ii less than 1 m/sec2, then the velocity will be 2 in/sec or less. For
frequencies from 10 Hz to 80 Hz a weighted acceleration of 1 m/sec2 is essen-
tially equivalent to a velocity of 1 in/sec. In most practical cases, in
which the acceleration is made up of several frequency components, an accel-
eration of less than 1 m/sec2 will also mean that the resultant velocity
will be less than* 2 in/sec, and possibly less than 1 in/sec, regardless
of frequency. Therefore, it is recommended that 1 m/sec2 be used as the
normally safe acceleration with respect to structural damage. Vibrations
above this should be avoided, or special arrangements should be made with the
owners of the exposed structures. Since some minor damage has occasionally
been reported at vibration as low as 1 in/sec, (0.5 m/sec2 to 1 a/sec2), expo-
sures in the range between 0.5 m/sec2 and 1 m/sec2 should also be regarded
as a potentially adverse exposure with respect to structural damage. Finally,
the safe peak acceleration for ancient monuments or ruins should be considered
as 0.05 m/sec2. Higher exposure values for such ancient structures should
not be considered safe without a detailed structural analysis.
No single-number index is suggested for summarizing Che structural
effects. Quantification of the impact will consist of a contour map and
tabulation, showing the number of structures above the potentially damaging
accelerations of 1 m/sec2 and 0.5 m/sec2. A description of the expected
damage and the likelihood of such damage occurring should be provided for
each type of structure. The information in Appendix D will be of some help
98
-------
in making this assessment, but sufficient data vill not often be available
to make this assessment fully. In such cases, a program for monitoring
the actual damage, or lack of it, may be necessary.
99
-------
CHAPTER 5
SUMMARY OF NOISI IMPACT ANALYSIS
This chapter provides an overview of the analysis that might be expected
to characterize noise impact fully, by summarizing the preceding chapters.
In addition, Figure 1 and Table 1 provide useful overviews of the kinds of
analyses suggested.
5.1 Purpose and structure of the guidelines
These guidelines contain procedures which can be used to describe and
quantify the noise-related impacts of proposed projects. The resulting de-
scription of noise impacts is intended to be easily understood by those
making decisions, so that consideration of these impacts can be an integral
part of the decision. The approach described here is applicable to any
situation calling for the evaluation of noise-related impacts, such as SIS or
environmental assessment preparation for the NEPA process, and is consistent
with noise evaluation procedures used by FAA, FHWA, and HUD, among others.
The approach is not mandatory, but is meant to complement these other proce-
dures by showing how to proceed to a quantitative description of impacts on
people (which is the ultimate goal of all procedures) from information on
noise levels (which those procedures require).
These guidelines provide procedures for arriving at qualitative, tabular,
and single number descriptions of noise environments. The quantitative
approaches rely on tables detailing the affected area or population, and on
a modification of the earlier fractional impact method [50] to reduce the
tabulated information to a single number index. These descriptions should be
applied to future as well as to immediate impacts.
100
-------
Three principal types of noise environments are covered; general audible
noise; special noises; and vibration. There is a separate chapter for each,
which covers (1) the appropriate physical measurement, (2) methods for pre-
dicting that measure for the proposed project and for determining the existing
levels, (3) human noise exposure criteria, and (4) procedures for quantifying
impact. Within the chapter on general audible noise, three subsections are
provided, entailing different approaches for human exposure criteria and
quantification procedures in different noise ranges: urban and suburban
settings	usually 55 to 75 dB); projects producing L(jn greater than
75 dB; and rural and wilderness areas (L,jn usually less than 55 dB).
Additional types of proposed actions for which these guidelines will
be useful are projects which entail new populations to be introduced into
noisy areas, and actions which are intended to reduce noise. The impact of
temporary projects may be evaluated using a more simplified analysis. For all
impact analysis, the necessary estimation and prediction entail uncertainty.
When possible, the degree of uncertainty should be specified. In some circum-
stances, optimistic and pess unistxc forecasts can be used to bracket the
estimate.
5.2 Analysis of impacts of general audible noise
General audible noise is noise as commonly encountered in the environ-
ment. Therefore, the material in chapter 2 should cover the great majority of
situations in which an evaluation of noise impacts is desired. The primary
measure of general audible noise is L^, and whenever possible, an approxi-
mation to the annual average value should be used. In some cases this measure
is inappropriate, and shorter term measures such as 1-hour Leq or the sound
101
-------
exposure level should be used. The screening diagram (Figure 3) shows chat
whenever the noise level after the project will be greater than the existing
level a noise analysis is necessary (i.e., when the existing level is less
than 10 dB greater than the project noise level). The diagram applies to both
permanent and temporary projects.
Depending on the approximate range of	values, different types of
noise effects are of concern, and therefore different analyses are needed
(Figure 14). At levels generally encountered in populated areas (approx.
L(jn values of 45 dB to 80 dB), the general health and welfare effects of
noise are the primary concern. At levels above 75 dB (8-hour Le(? at-ear)
severe health effects become important. The threshold level at which these
should be investigated is an	of 75 dB. In rural or wilderness areas,
with very low residential populations, environmental degradation is as much
a concern as the effect of noise on residents. In such areas, judgment will
have to be used in deciding between a health and welfare analysis and an
environmental degradation analysis, depending more on characteristics of
the area than on the existing or project noise level.
Regardless of which noise effects are the focus, two elements are always
recommended for describing the impact. The first is a table (or set of
tables) setting out the number of people and total area affected as a function
of different noise levels. Five decibels is usually an appropriate interval
to use for those tables. The second element is a verbal, qualitative descrip-
tion of the principal components of the impacts identified in the tables.
For general health and welfare effects and for severe health effects
the quantitative analysis can proceed further, to calculate a single-number
index which summarizes all the impacts. The human noise effects information
discussed in the Levels Document applies in "the general health and welfare
102
-------
SEVERE HEALTH EFFECTS (SEC. 2.3)
HEALTH AND . .
WELFARE EFFECTS
HEALTH AND WELFARE
EFFECTS (SEC* 2.2)
POSSIBLY


ALL PROJECTS
SCREENED OUT

ENVIRONMENTAL
DEGRADATION
(SEC 2.41
«v»v.
60	70
EXISTING Ldn(y)
FIGURE 14. TYPES OF ANALYSES SUGGESTED
103
-------
effects range: speech interference, sleep interruption, annoyance, and
possible health effects. Given the existence of Schultz's synthesis [6], it
is appropriate to use the percent of people who report being highly annoyed
as the indicator of general adverse response, and to use his equation to
summarize the total impact of noise on residential areas in terms of the
number of people responding adversely to the noise. In the severe health
effects range, the human noise exposure effects may include cardiovascular
effects and other stress-related health problems. It is not known yet at
what levels these begin to occur, but it is known that at an 8-hour L of
eq
75 dB hearing damage (NIPTS) begins to occur. The curve for average NIPTS
versus	is used as the function to reduce tabulated data for these
extreme levels to a single-number indicator, because it is the only direct
health effect for which such a function has been established.
5.3 Analysis of impacts due to special noises
The special noises discussed in this document are impulse noise, infra-
sound, ultrasound, and noises with information content. Effects on humans,
structures, and animals all need to be considered.
For any special noise, the main task is to describe the noise environment
for the population. As with general audible noise, tables such as those in
Chapter 2 may be needed. Except for large impulse sounds, only a verbal,
qualitative description of the effects of the special noise is recommended.
The criteria of Chapter 3 should be cited, but in many cases additional
documentation may be required. A discussion of previous experience with
such noises should be made, if possible. For high-energy impulse noise,
the analysis can be carried further and the expected percent highly annoyed,
and changes in this quantity, can be estimated.
104
-------
For structures exposed to impulse noise, the noise environment should
be described for each building or set of buildings in terms of maximum
sound pressure levels. Either a worst case or a statistical estimate of
the distribution of maximum levels should be provided. A discussion of
possible structural damages is required. The chance that such effects could
occur should be estimated. Finally, the significance of such damage, in
monetary and/or non-monetary terms, should be estimated.
5.4 Analysis of impacts due to vibration ¦
If people are exposed, the analysis should include documentation of the
vibration environment such that the expected vibration acceleration values due
to the action are provided for all residential and other sensitive areas in
which the weighted acceleration exceeds the "110 complaint" level (Table 12).
The change in the vibration environment can be discussed both by using the
average Vibration Impact Index for the exposed population and by listing the
expected effects at the nearest residence. A discussion of the effects of
the vibration environment on sensitive non-residential buildings is also
needed.
When structures are exposed to potentially damaging vibration, a descrip-
tion of the expected damage and the likelihood of such damage occurring should
be provided for each type of structure. The information in Appendix G will
be of some help in making this assessment, but often enough data will not be
available to make a complete assessment. In such cases, a program for moni-
toring the actual damage, or lack of it, may be necessary.
105
-------
REFERENCES
1.	Council on Environmental Quality, National Environmental Policy Act-
Regulations, Federal Register, Vol, 43, No, 112, June 9, 1978, pp. 25230-
25247.
2.	"Information on Levels of Environmental Noise Requisite To Protect Public
Health and Welfare with an Adequate Margin of Safety," Report 550/9-74-004,
U.S. Environmental Protection Agency, March 1974.
3.	"Guidelines for Considering Noise in Land Use Planning and Control,"
Federal Interagency Committee on Urban Noise, June 1980.
4.	"Sound Level Descriptors For Determination of Compatible Land Use," ANSI
S3.23-1980, American National Standards Institute.
5.	"Assessment of Community Response to High-Energy Impulsive Sounds,"
Report of Working Group 84, Committee on Hearing, Bioacoustics and Bio-
mechanics, The National Research Council, Washington, D.C, 1981.
6.	Schultz, T. J. , "Synthesis of social surveys on noise annoyance, J_.
Acoust. Soc. Am., 64 (2), 1978, pp. 377-405.
7.	"Public Health and Welfare Criteria for Noise," Report 550/9-73-002, U.S.
Environmental Protection Agency, July 1973.
8.	"Community Noise," Report NTID 300.3, U.S. Environmental Protection
Agency, December 31, 1971.
"Code of Current Practices for Enforcement of Model Noise Control
Ordinance," U.S. Environmental Protection Agency, September 1981.
R-l
-------
10.	Kurze, U.J., Levison, W.H., and Serben, S., "User's Manual Cor the Pre-
diction of Road Traffic Noise Computer Programs," Report DQT-TSC-315-1, U.S.
Department of Transportation, Kay 1972.
11.	Gordon, C.G., Galloway, W.J., Kugler, B.A., and Nelson, D.L., "Highway
Noise - A Design Guide for Engineers," Report 117, National Cooperative High-
way Research Program, 1971.
12.	Kugler, B.A., and Fierson, A.G., "Highway Noise - a Field Evaluation of
Traffic Noise Reduction Measures," Report 144, National Cooperative Highway
Research Program, 1973.
13.	"Planning in the Noise Environment," Joint Services Manual AFM 19-10,
TM 5-803-2, and NAVFAC P-970, June 1978.
14.	"FFA Integrated Noise Model Version 1: User's Guide," Report FAA-EQ-78-
01, Federal Aviation Administration, 1978.
15.	"Calculation of Day-Night Levels (L^n) Resulting from Civil Aircraft
Operations," Report 550/9-77-450, U.S. Environmental Protection Agency, 1977.
16.	Galloway, W.J., Eldred, K. McK., and Simpson, M.A., "Population Distri-
bution of the United States as a Function of Outdoor Noise Level," Report
550-9-74-009, U.S. Environmental Protection Agency, June 1974.
17.	Borsky, P.N., "The use of social surveys for measuring community re-
sponses to noise environments," in Transportation Noises, J.D. Chalupnik
(ed). University of Washington Press, Seattle, 1970, pp. 219-227.
R-2
-------
18.	Schultz, T.J., "Social surveys on noise annoyance - further consider-
ations." in Proceedings of the Third International Congress on Noise as a Pub-
lic Health Problem, J.V. Tobias (ed). American Speech and Hearing Associa-
tion, Washington, D.C., 1979.
19.	von Gierke, H.G. (Task Group Chairman), "Impact Characterization of Noise
Including Implications of Identifying and Achieving Levels of Cumulative Noise
ExposureReport NTID 73.4, U.S. Environmental Protection Agency, Aircraft/
Airport Noise Study Report, July 1973.
20.	"Noise-Final Report," H.M.S.O., Cmnd. 2056, London, July 1963.
21.	Connor, W.K. and Patterson, H.P., "Community Reaction to Aircraft Noise
Around Smaller City Airports," NASA CR-2104, August 1972.
22.	"Social and Economic Impact of Aircraft Noise," Sector Group on the Urban
Environment, OECD, April 1973.
23.	Lukas, J.S., "Measures of Noise Level: Their Relative Accuracy in Pre-
dicting Objective and Subjective Responses to Noise during Sleep," Report
600/1-77-010. U.S. Environmental Protection Agency, February 1977.
24.	Goldstein, J., "Assessing the impact of transportation noise: human
response measures," in Proceedings of the 1977 National Conference on Noise
Control Engineering, G.C. Haling (ed). Noise Control Foundation, Pough-
keepsie, New York, 1977, pp. 79-98.
25.	Goldstein, J. and Lukas, J.S., "Noise and Sleep: Information Needs for
Noise Control," in Proceedings of the Third International Congress on Noise
as a Public Health Problem, J.V. Tobias (ed). American Speech and Hearing
Association, Washington, D.C., 1979.
R-3
-------
26.	"Noise Emission Standards for Surface Transportation Equipment: Reg-
ulatory Analysis of the Noise Emission Regulations for Truck-Mounted Solid
Waste Compactors," Report 550/9-79-257, U.S. Environmental Protection Agency,
August 1979.
27.	Galloway, W.J., "Evaluating the Impact on the Public Health and Welfare
of a Change in Environmental Noise Exposure," Appendix D of "Design Guide for
Highway Noise Prediction and Control," Final Report Project 3-7/3, Submitted
to Transportation Research Board, NCH1P, National Academy of Sciences,
November 1974.
28.	Baughn, W.L., "Relation Between Daily Noise Exposure and Hearing Loss
Based on the Evaluation of 6,835 Industrial Noise Exposure Cases," Joint
EPA/USAF Study, prepared for 6570th Aerospace Medical Research Laboratory,
Wright-Patterson AFB, Ohio. AMRL-TR-73-53, 1973.
29.	Passchier-Vermeer, W., "Hearing Loss Due to Exposure to Steady-State
Broadband Noise." Instituut Voor Gezondheidstechniek, Sound and Light
Division, Report 35, April 1968 (with supplement, 1969).
30.	Robinson, D.W. , "Estimating the risk of hearing loss due to exposure to
continuous noise," Occupational Hearing Loss, British Acoustical Society
Special Volume No. 1, London and New York, Academic Press, 1971, pp. 43-62.
31.	Johnson, D.L. "Prediction of NIPTS Due to Continuous Noise Exposure"
Report 550/9-73-001-B (or AMRL-TR-73-91), U.S. Environmental Protection
Agency, 1973.
R-4
-------
32.	Harrison, R.T., Clark, E.N., and Stankey, G.H., "Predicting Impact of
Noise on RecreationistsID&T Project No. 2688, U.S. Department of Agricul-
ture, Equipment Development Center, April 1980.
33.	Borsky, P.N. , "Community Reactions to Sonic Booms in the Oklahoma City
Area," Report AMKL-TR-65-37, National Opinion Research Center, 1965.
34.	Schomer, P.O., "Community Reaction to Impulse Noise: Initial Army
Survey," Report, CIRL-TR-N-100, U.S. Army Construction Engineering Research
Laboratory, June 1981.
35.	Schomer, P.D., "Evaluation of C-weighted L
-------
41.	Schemer, P.O., Goff, R.J., and Little, L.M., "The Statistics of Amplitude
and Spectrum of Blasts Propagated in the Atmosphere," Vol. I., Report CERL-TR-
N-13, U.S. Army Construction Engineering Research Laboratory, 1976,
42.	"Airblast Characteristics for Single Point Explosions in Air, With Guide
to Evaluation of Atmospheric Propagation and Effects," Draft ANSI 32.20-198X.
43.	Johnson, L. "Auditory and physiological effects of infrasound," Inter-
noise 75 Proceedings, Sendai, Japan, 1975, pp. 475-482.
44.	von Gierke, H.E. and Parker, D.E., "Infrasound", in Handbook of Sensory
Physiology, Vol. 5, Auditory System, Part 3, Springer-Verlag, Berlin-Heidel-
berg-New York, 1976, pp. 585-624,
45.	"Guide for the Evaluation of Human Exposure to Whole-body Vibration," ISO
2631-1978, International Organization for Standardization, and Addendum 2,
"Vibration and Shock Limits for Occupants in Buildings."
46.	"Guide for the Evaluation of Human Exposure Co Whole-body Vibration,"
ANSI S3.18-1979, American National Standards Institute.
47.	"Guide for the Evaluation of Human Exposure to Vibration in Buildings,"
Proposed ANSI S3.29-198X, American National Standards Institute.
48.	Nicholls, H.R., Johnson, C.F., and DuvalI, W.I., "Blasting Vibrations
and their Effects on Structures," Bulletin 656, U.S. Department of the In-
terior, Bureau of Mines, 1971.
49.	Siskind, D.E., Stagg, M.S., Kopp, J.W., and Dowding, C.H., "Structure
Response and Dosage Produced by Ground Vibration From Surface Mine Blasting,"
Report RI 8507, U.S. Department of the Interior, Bureau of Mines, 1980.
R-6
-------
50. "Guidelines for Preparing Environmental Impact Statements on Noise,"
Report of Working Group 69, Committee on Hearing, Bioacoust ics and Bio-
mechanics, The National Research Council, Washington, D.C, 1977.
R-7
-------
APPENDIX A
ACOUSTICAL TERMS AND SYMBOLS USED IN THE GUIDELINES,
AND SOME MATHEMATICAL FORMULATIONS FOE THEM
A.1. Acoustical terms
Some acoustical terms are defined or described here, which have been
used in the main body of this report. They are arranged alphabetically, to
facilitate finding then as needed. Three key terms—sound level, equivalent
sound level, and sound exposure levels-receive non-technical as well as
technical descriptions.
A.1.1 C-weighted sound exposure level. In decibels, the level of the
time integral of C-weighted squared sound pressure, with reference to the
square of 20 micropascals and to one second.
A. 1.2 day-night sound level. The 24-hour equivalent sound level, in deci-
bels, obtained after addition of 10 decibels to sound levels in the night
from midnight up to 7 a.m. and from 10 p.m. to midnight (0000 up to 0700
and 2200 up to 2400 hours).
A.1.3 day—night sound level contour. A curved line connecting places on
a map where the day-night sound level is the same. If only one kind of
contour is shown on the map the fact may be made known by a single legend,
"Contours of day-night sound level in decibels." In this case only the number
of decibels need be marked on a contour.
A. 1.4 day sound level. Equivalent sound level over the 15-hour time period
from 7 a.m. up to 10 p.m. (0700 up to 2200 hours).
A-l
-------
A.1.5 decibel. A unit measure of sound level and other kinds of levels.
It is a logarithmic measure. For sound level specifically it is equal to 10
log 
-------
A.1.11 impulse sound level. In decibels, Che exponential-time-average
sound level obtained with a squared—pressure time constant of 35 milliseconds.
A. 1.12 instantaneous sound pressure, overpressure. Pressure at a place
and instant considered, minus the static pressure there.
A.1.13 maximum sound pressure level. Same as peak sound pressure level,
provided that the time interval considered is not less than a complete
period of a periodic wave.
A.1.12 instantaneous sound pressure, overpressure. Pressure at a place
and instant considered, minus the static pressure there.
A.1.13 maximum sound pressure level. Same as peak sound pressure level,
provided that the time interval considered is not less than a complete
period of a periodic wave.
A.1.14 night sound level. Equivalent sound level, in decibels, over the
nine-hour period from midnight up to 7 a.m. and from 10 p.m. to midnight C0000
up to 0700 and 2200 up to 2400 hours).
A.1.15 noise level. Same as sound level, for sound in air. Some people
use "noise" only for sound that is undesirable. A sound level meter does
not, however, measure people's desires. Hence there is less likelihood of
misunderstanding, if what is measured by a sound level meter is called sound
level, rather than noise level.
A.1.16 peak sound pressure. Greatest absolute instantaneous sound pressure
in a stated frequency band, during a given time interval. (Also called
peak pressure.)
A-3
-------
A.1.17 peak sound pressure level. In decibels, twenty times the common
logarithm of the ratio of a greatest absolute instantaneous sound pressure
to the reference sound pressure of twenty micropascals.
A.1.18 slow C-weighted sound level. In decibels, the exponential time
average sound level measured with the squared-pressure time constant of one
second and the C-frequency weighting of the sound level meter.
A.1.19 slow sound level. In decibels, the exponential-time-average sound
level measured with the squared-pressure time constant of one second.
A.1.20 sound exposure. Time integral of squared, A~frequency-weighted
sound pressure over a stated tine interval or event. The exponent of sound
pressure and the frequency weighting may be otherwise if clearly so specified.
A.1.21 sound exposure level. The level of sound accumulated over a given
time period or event. It is particularly appropriate for a discrete event
such as the passage of an airplane, a railroad train, or a truck. Sound
exposure level is not an average, but a kind of sum. In contrast to equi-
valent sound level which may tend to stay relatively constant even though
the sound fluctuates, sound exposure level increases continuously with the
passing of time. Technically, sound exposure level in decibels is the level
of the time integral of A-weighted squared sound pressure over a stated
time interval or event, with reference to the square of the standard reference
pressure of 20 micropascals and reference duration of one second.
A.1.22 sound level. The weighted sound pressure level, which reduces to
a single number the full information about sound pressure levels across
the frequency range 20 Hz to 20 kHz. It can be measured by a sound level
A-4
-------
meter which meets the requirements of American National Standard Specification
for Sound Level Meters Si.4-1971. In these guidelines, fast time-averaging
and A-frequency weighting are understood, unless others are specified.
The sound level meter with the A-weighting is progressively less sensitive
to sounds of frequency below 1000 hertz (cycles per second), somewhat as is
the ear. With fast time averaging the sound level meter responds particularly
to recent sounds almost as quickly as does the ear in judging the loudness
of a sound.
A. 1.23 sound pressure. Root-mean-square of instantaneous sound pressures
over a given time interval. The frequency bandwidth must be identified.
A. 1.24 sound pressure level. In decibels, twenty times the common logarithm
of the ratio of a sound pressure to the reference sound pressure of twenty
micropascals (0.0002 microbar). The frequency bandwidth must be identified.
A.1.25 (vibratory) acceleration. The rate of change of velocity of a vibra-
tion, in a specified direction. The frequency bandwidth must be identified.
A.1,26 (vibratory) acceleration level. In decibels, twenty times the common
logarithm of the ratio of a vibratory acceleration to the reference accelera-
tion of ten micrometers per second squared (nearly one-millionth of the stan-
dard acceleration of free fall). The frequency bandwidth must be identified.
A.1.27 yearly day—night sound level. The day-night sound level, in decibels,
averaged over an entire calendar year.
A-5
-------
A.2. Symbols	used in the guidelines
A.1.1	C-weighted sound exposure level
A, 1.2	day-night sound level
A.1.5	decibel
A.1.7	8-hour equivalent sound level
A.1.8	equivalent sound level
A. 1.10	hourly equivalent sound level
A. 1.17	peak sound pressure level
A.1.21	sound exposure level
A. 1.23	sound pressure
A,1.25	vibratory acceleration
A. 1.27	yearly day-night sound level
1*SG
l*dn
dB
l*eq(8)
^eq
Leq(l)
kpk
I*
P
a
^dn(y)
A.3. Mathematical formulations for the descriptors used in the guidelines
A.3.1 Equivalent sound level
^eq * *°9iq
1
T
/»

dt
Eqn A-l
where: T is the length of the time interval during which the average is
taken, and L^(t) is the time varying value of the A-weighted
sound level during the time interval T.
Note: Equivalent sound level may be calculated from the sound expo-
sure levels of individual events occurring within the time
interval T:
Leq " 10 log1Q
I
T
Wio
Tu
i-1
Eqn A-2
A-6
-------
where: Lg £ is the sound exposure level of the i-th event, out of
a total of n events in time interval T, Lg is defined in
A.2.3.4.
A.3.2 Day-night Sound Level
0700
["<3n " 10 lo9
10
1
86400
/
0000
[L.
-------
A.3*4 Sound Exposure Level
Xjjg ® 10 loc| *J Q
(/V'^0 at)
Eqn A-6
where: L^(t) is the time-varying A-weighted sound level in some time
interval to t2-
The length of the time interval may be arbitrary, or it may simply be
large enough to encompass all the significant sound of an event.
Note: The value of the above integral is usually approximated with
sufficient accuracy by integrating L^(t) over the time in-
terval during which L^(t) is between 10 decibels less than its
maximum value and the maximum value, before and after the
maximum occurs.
A.3.S C-weighted Sound Exposure Level
where: L^(t) is the time-varying C-weighted sound level in some time
interval tj_ to t£.
Note: In practice the integral is often approximated by integration
within the time during which the sound level of the event
exceeds some threshold value such as 20 d& less than the maximum
sound pressure level.
(
\ti
Eqn A-7
A-8
-------
A.3.6 C-weighted Day Night Sound Level
Analogous Co the A-weighted Ldn, with a nighttime penalty of 10 dB,
the C-weighted day-night average sound level is:
*fcdn * 10 log10 24
15 x 10
ha
to
+ 9 x 10

+ 10
10
Iqn A-8
L ^ is the average C-weighted sound level over the daytime period
of 0700 to 2200 hours, Lcn is the C-weighted average level over the
nighttime period of 2200 to 0700 hours.
The C-weighted average level is most easily calculated from the
C-weighted sound exposure levels during the time of interest as follows;
n Lsci
£l0 10 for
1^ « 10 log 15 x 36Q0
he-.
>80
Eqn A-9
I^n - 10 leg g x mQ
2> 10
fear
^SC;
>70
Eqn A-l0
where Lg(j is the C-weighted sound exposure level of the i-th discrete
event.
A-9
-------
APPENDIX 1
ENVIRONMENTAL NOISE MEASURES AND
PROCEDURES
B-l
-------
B1. ENVIRONMENTAL NOISE MEASURES AND THEIR
PURPOSES IN FEDERAL PROGRAMS
1. FEDERAL INTERAGENCY
COMMITTEE ON URBAN
NOISE (DOT, DOD. EPA.
VA. HUO)
2. FHWA
1 EPA
4. HUD
fc FAA
7. VA
Type of
froyMM
Policy
Uttilonn F(d«r«l position
on noiM aiul land uta
planning lor state and
local sowrnmtnit and
others.
Highway NoiM
Policy
Health & Wilfaii
Guidance
HUO NoiM
Regulations
Airport Installation
Compatible Uu
Zones IAICUZI
Program
Airport NoiM
Compatibility
Planning
VA NoiM
Policy
Key Documents
Guidelines lor Considering
Noim in Land Ute Planning
and Control (19001
NTlS: PB 81 214-124
Land Use Compatibility
Guidelines
FHPM 7 7 3
(May 1ft76)
(Latest
revision.
May 1070)
Design NoiM
Lewab
EPA " Leveb"
Document (1074)
Levels which ara
required to pro •
Met the public
health and welfare
with an adequate
margin of Mlety.
24 CRF P«t 61
Subpart B; NoiM
Assessment Guide-
lines (10B0L
Levels which
determine whether
proposed si Ms
are eligible for
HUO insurance or
assistance.
DOO Instruction
4166.67 (10771
Levels used as
"reasonable"
guidance to com-
munities for plan*
ning.
Aviation Safety
end NoiM Abate-
ment Act of 1070
(ASNA). Federal
Aviation Regula-
tion. Part 160.
Land uws that
are normally com*
patible or non-
compatible with
various levels of
noiM exposure by
individual.
Section Vllf
AppraiMl of
residential
properties
near Airport!
(1060).
Levels determin-
ning whether
projected sites
are eligible for
VA assistances
Purport of L eve hi
Provides land um planning
guidance to communities and
states. Guidelines mi forth
linkages between various
nuiu levels and compatible
land um. Guidelines balance
effects ol noiM on the
community against local
developmental needs, costs,
and feasibility, facilitating
local decisions as to
compatibility of specific
developmental projects with
specific local noiM conditions.
Daiaipbxs
Used
All sources
*~dn
TheM levels are
used In deter •
mining where
noiM mitigation
on a particular
highway project
is warranted.
Tltey reflect
cost and feasi ~
bility considera -
tions. They are
not appropriate
ImkI um criteria.
Design noiM
levels depend
upon land um
activity.
Higliway only
tor design hour
TheM leveb iden-
See above. Leveb
Guidance to com -
Guidance for deter-
Establishes NoiM
tify in scientific
can be used as
munities for plan -
mining compatible
limits beyond
terms the threshold
general planning
ning. Considers
or no incompatible
which VA will
of effect. While the
levels. Reflects
balance between
land use* for air-
not accept resi-
levels have relevance
costs, feasibility.
cost, feasibility.
port noiM exposure
dential cons truce
for planning, they do
general program
effect, community
map* and airport
tion. While the
not in themselves
objectives snd
development needs
noiM compatibtity
levels have
form the sole basis
consideration of
and availability
programs submitted
relevance for
lor appropriate land
health and wel •
of land for
to the FAA under
planning, they
um actions becauM
fare goab.
development.
Title 1 of the ASNA
do not In them-
they do not consider

Community wide
Act for formal
Mlves form the
cost, feasibility or

consideration.
approval.
sole besis for
the development needs



appropriate land
of the community.



um actions
The user should



becauM they do
make such tradeoffs.



not consider




cost, feasibility




or the develop-




ment needs of




the community.




The user should




make such trade-




offs.
All sources
All sources
Military •
Civil Airports
Airports only


Airfields


*~dn
Various
u.
Ldn
Various

(accept 11^1

(including Ldnl
-------
B.2. Estimating from other Noise Measures
The equations listed here are approximations only, and are provided
for use in those situations in which measurement or prediction of the other
noise measure is already available. If no such information is available, it
is strongly recommended that "L^n be measured or predicted directly, instead
of using these equations.
NEF:
Ldn*
NIF + 35
Eqn B-l
CNR:
I-do*
CNR - 35
Iqn B-2
CNEL:
**dn 85
CNEL
Iqn B-3
24-hour Lgq•
Ldn«
Leq(24) + 4
Iqn B-4
Peak (traffic) hour
Ldn ®
Leq(1)
Iqn B-5
Peak (traffic) hour L^q
Ldn 88
L10 "3
Eqn B-6
Notes:
3Source: [19], Parts II B, F, and Addendum A, approximated.
^Source: Department of Housing and Urban Development. Notice of proposed
rulemaking, Environmental criteria and standards, Federal Register, Vol
43, No. 249, December 29, 1978, p. 60399. "The day-night average sound level
may be estimated from the design hour I4Q or Le^ values by [these]
relationships, provided heavy trucks do not exceed 10 percent of the total
traffic flow in vehicles per 24 hours and the traffic flow between 10 p.m.
and 7 a.m. does not exceed 15 percent of the average daily traffic flow in
vehicles per 24 hours."
B-3
-------
APPENDIX C
SUMMARY OF HUMAN EFFECTS OF GENERAL AUDIBLE NOISE
TABLE CI Summary of Human Effects for Outdoor Day-Night Sound Level of 75
Decibels
Type of Effect
Hearlag Loss
Magnitude of Effect
Hay begin to occur in sensitive individuals, depending
nn arfufl 1 nnt a a 1 atra 1 a vat* a iirad of •oat"
wU as* b UBl UW*iBC &6VCii3 4 QWC Bvl al> CB4 •
Risk of non-auditory
health effects
(stress)
f
Speech - Indoors
Outdoors
Some disturbance of normal conversation. Sentence
intelligibility (average) approximately 98%
Very significant disturbance of normal voice or relaxed
conversation with; 100% sentence intelligibility
not possible at any distance
or, 99% sentence intelligibility (average) at 0.15
meter
or, 95% sentence intelligibility (average) at 0.5
meter
High Annoyance
Average Community
Reaction
Attitudes Towards
Area
Depending on attitude and other non-acoustical factors,
approximately 37% of the population will be highly
annoyed.
Very severe; 13 dB above level of significant "com-
plaints and threats of legal action" and at least 3 dB
above "vigorous action" (attitudes and other non-
acoustical factors may modify this effect).
Noise is likely to be the most important of all adverse
aspects of the community environment.
~Research implicates noise as one of several factors producing stress-related
health effects such as heart disease, high-blood pressure and stroke, ulcers
and other digestive disorders. The relationships between noise and these
effects have not yet been quantified, however.
^The speech effects data in these tables are drawn from the Levels Document,
as follows. Indoor effects are based on Table 3, and on Fig. D-l, with 15 dB
added to the indoor level to obtain the outdoor reading. Outdoor effects
come from Fig. D—2, using Lj (as determined with Fig. A-7). Both Figures
D-l and D-2 are based on steady noise, not on Leq. Table D-3 shows that
for a fluctuating noise, the average percent interference can be higher or
lower than for steady noise with the same L0q, The values given in this
report are the best estimates of the interference.
-------
TABLE C2 Summary of Human Effects for Outdoor Day-Night Sound Level of
70 Decibels
Type of Effect
Hearing Losa
Risk of non-auditory health
effects (stress)
Speech - Indoors
Outdoors
Magnitude of Effect
Will not likely occur
See Table CI
Slight disturbance of normal conversation
approximately 99% sentence intelligibility
(average)
Significant disturbance of normal voice or
relaxed conversation with 100% sentence
intelligibility (average) possible only at
distances less than 0.1 meter
or
992 sentence intelligibility (average) at
0.3 meter
High Annoyance
Average Community Reaction
or
95% sentence intelligibility (average) at
0.9 meter
Depending on attitude and other non-
acoustical factors, approximately 25
percent of the population will be highly
annoyed.
Severe; S dB above level of significant
"complaints and threats of legal action,"
but at least 2 dB below "vigorous action"
(attitudes and other non-acoustical
factors may modify this effect)
Attitudes Towards Area
Noise is one of the most important adverse
aspects of the community environment
-------
TABLE C3 Summary of Human Effects for Outdoor Day-Night Sound Level of
65 Decibels
Type of Effect
Hearing Loss
Risk of non-auditory health
effects (stress)
Speech - Indoors
Outdoors
Magnitude of Effect
Will not occur
See Table Cl
Slight disturbance of normal conversation
992 sentence intelligibility (average)
with a 4 dB margin of safety
Significant disturbance of normal voice or
relaxed conversation with 1002 sentence
intelligibility (average) at 0.15 meter
or
99% sentence intelligibility (average) at
0.5 meter
High Annoyance
Average Community Reaction
or
95% sentence intelligibility (average) at
1.5 meters
Depending on attitude and o*„er non-
acoustical factors, approxinately 15
percent of the population will be highly
annoyed.
Significant; 3 dB above level of significant
"complaints and threats of legal action,"
but at least 7 dB below "vigorous action"
(attitudes and other non-acoustical
factors may modify this effect)
Attitudes Towards Area
Noise is one of the importar/ adverse
aspects of the community environment
-------
TABLE C4 Summary of Human Effects for Outdoor Day-Night Sound Level of
60 Decibels
Magnitude of Effect
Will not occur
See Table Cl
No disturbance of normal conversation
100% sentence intelligibility (average)
with no margin of safety
Moderate disturbance of normal voice or
relaxed conversat LQQ with 100% sentence
intelligibility (average) at 0.2 meter
or
99% sentence intelligibility (average) at
0.6 meter
or
95% sentence intelligibility (average) at
2 meters
High Annoyance	Depending on attitude and other non-
acoustical factors, approximately 9
percent of the population will be highly
annoyed.
Average Community Reaction	Slight to moderate; 2 dB below level of
significant "complaints and threats of
legal action," but at least 11 dB below
"vigorous action" (attitudes and other
non-acoustical factors may modify this
effect)
Attitudes Towards Area	Noise may be considered an adverse aspect
of the community environment
Type of Effect
Hearing Loss
Risk of non-auditory health
effects (stress)
Speech - Indoors
- Outdoors
C-4
-------
TABLE C5 Summary of Human Effects for Outdoor Day-Night Sound Level of
55 Decibels
Type of Effect
Hearing Loss
Risk of non-auditory health
effects (stress)
Speech - Indoors
Outdoors
Magnitude of Effect
Will not occur
See Table Cl
No disturbance of normal conversation
1001 sentence intelligibility (average)
with a 5 dl margin of safety
Slight disturbance of normal voice or
relaxed conversation with: 100Z sentence
intelligibility (average) at 0.35 meter
or
992 sentence intelligibility (average) at
1.0 meter
High Annoyance
Average Community Reaction
Attitudes Towards Area
or
95% sentence intelligibility (average) at
3.5 meters
Depending on attitude and other non-
acoustical factors, approximately 4
percent of the population will be highly
annoyed.
None expected; 7 dB below level of signi-
ficant "complaints and threats of legal
action," but at least 16 dB below "vigorous
action" (attitudes and other son-acoustical
factors may modify this effect)
Noise considered no more important than
various other environmental factors
C-5
-------
APPENDIX D
MEASUREMENT OF AND CRITERIA FOR HUMAN VIBRATION EXPOSURE
D.l. Introduction
The criteria for vibration exposure in this appendix will address 3
types of effects. These three types of effects are: Cl) whole body vibration
of humans, (2) annoyance and interference caused by building vibration, and
(3) structural damage from building vibration.
The existing state of knowledge is not complete in any of the above
three areas; however, there are existing I.S.O. standards that have been
approved or proposed. Summaries of these standards, along with other data,
provide the content of this appendix. Some simplification of the proposed
standards on building vibration and structural damage have been made in
order to provide a simple, unified and reasonable method for assessing the
effects of vibration,
D.2. Whole body vibration criteria (Summary of Approved ISO Standard 2631-
1978)
D.2.1 The three criteria for evaluation of whole body vibration
Experimental data show that there are various rather complex factors
that determine the human response to vibration. Evaluation of all these
factors is difficult at this time because of the paucity of quantitative
data concerning man's perception of vibration and his response to it. Never-
theless, there is an international standard which does provide provisional
guidance as to what is acceptable human exposure to vibration for some types
of vibration.
In general, there are four physical factors of primary importance in
determining the human response to vibration. These are intensity, frequency,
D-l
-------
direction, and exposure time of the vibration. The current International
Standard for vibration addresses three main human criteria. These are:
1.	Preservation of working efficiency
2.	Preservation of health or safety
3.	The preservation of comfort
For environmental problems, the preservation of comfort is considered the
best criteria for evaluation of whether or not vibration significantly changes
the environment.
D.2.2 Types of vibration transmissions
The standard lists basically three kinds of human response to vibration,
namely:
(a)	Vibrations transmitted simultaneously to the whole body surface
or substantial parts of it. This occurs when the body is immersed in a
vibration medium. There are circumstances in which this is of practical
concern; for example, when high intensity sound in air or water excites
vibrations of the body.
(b)	Vibration transmitted to the body as a whole through the supporting
surface, namely, the feet of a standing man, the buttocks of a seated man
or the supporting area of a reclining man. This kind of vibration is usual
in vehicles, in vibrating buildings and in the vicinity of working machinery,
(c)	Vibrations applied to particular parts of the body such as the
head or limbs; for example, by vibrating handles, pedals, or head-rests,
or by the wide variety of powered tools and appliances held in the hand.
It is also possible to recognize the condition in which an indirect
vibration nuisance is caused by the vibration of external objects in the
visual field (for example, an instrument panel).
D-2
-------
The International Standard 2631, however, applies chiefly to the common
condition (b) above; and, in particular, where the vibration is applied
through the principal supporting surface to the body of a standing or seated
man. In the case of vibrations applied directly to a reclining or recumbent
man, insufficient data are available to make a firm recommendation; this
is particularly true of vibration transmitted directly to the head, when
tolerability is generally reduced. Tolerance may also be reduced when condi-
tions (b) and (c) exist together. Provisionally, however, the limits for
the standing or seated man may also be used fot the reclining or recumbent
man. It must be appreciated that some circumstances will arise in which the
rigorous application of these limits would be inappropriate.
D.2.3 Direction of vibration
Rectilinear vibrations transmitted to man should be measured in the
appropriate directions of an orthogonal coordinate system centered at the
heart. The standard specifies separate criteria according to whether the
vibration is in the longitudinal ( + az) direction or transverse (+^ ax or
ay) plane. Accelerations in the foot (or buttocks) - to head (or longi-
tudinal) axis are designated + az: acceleration in the fore-and-aft (ante-
posterior or chest-to-back) axis, _+ ax; and in the lateral (right-to-left
side) axis, +_ ay. These axes are illustrated in Figure D-l.
D.2.4 Acceptable whole body vibration
The ISO standard identifies the 24-hr comfort level for rms pure (sinu-
soidal single) frequency or rms value in third octave band for random vibra-
tion as given in Table D-l. As long as the vibration levels are below the
24-hr levels, vibration should be considered to have no direct impact on an
individual, regardless of the duration of the exposure. The standard does
-------
W77m
wmm
a,, ay, az * acceleration in the directions of the *, y, 2 axes
x axis = back to chest
y axis ¦ right to left side
z axis 3 foot for buttock Ssi-to*head
FIGURE D—1. Directions of co ordinate system for mechanical vibrations influencing humans
V
D-4
-------
TABLE D-l - Numerical values of "comfort boundary" for vibration acceleration
in the longitudinal, az, direction (foot (or buttocks)-to-head
direction) (see Figure D-l and in the transverse, or «y, direc-
tion (back-to-chest or side-to-side)
Values define the boundary in terms of rss value of pure (sinusoidal) single
frequency vibration; or rms value in third-octave band for distributed vibra-
t ion.
ACCELERATION m/sec
Frequency (Hz)
(Center Frequency
of 1/3 Octave Band)

az


«x or ay

1 min
8 hr
24 hr
1 min
8 hr
24 hr
1
1.78
0.2
0.07
0.63
0.07
0.03
1.25
1.59
0.18
0.06
0.63
0.07
0.03
1.6
1.43
0.16
0.06
0.63
0.07
0.03
2.0
1.27
0.14
0.05
0.63
0.07
0.03
2.5
1.13
0.13
0.04
0.79
0.09
0.04
3.15
1.00
0.11
0.04
1.0
0.11
0.05
4.0
0.89
0.1
0.04
1.27
0.14
0.06
5.0
0.89
0.1
0.04
1.59
0.18
0.08
6.3
0.89
0.1
0.04
2.00
0.24
0.10
8.0
0.89
0.1
0.04
2.54
0.29
0.13
10.0
1.13
0.13
0.04
3.17
0.36
0.16
12.5
1.43
0.16
0.06
3.97
0.44
0.20
16.0
1.78
0.2
0.07
5.08
0.57
0.25
20.0
2.25
0.25
0.09
6.35
0.71
0.32
25.0
2.86
0.32
0.11
7.94
0.89
0.40
31.5
3.56
0.40
0.14
10.00
1.13
0.51
40 * 0
4.44
0.51
0.18
12,70
1.43
0.63
50.0
5.71
0.63
0.23
15.87
1.78
0.79
63.0
7.11
0.79
0,29
20.00
2.25
1.00
80.0
8.89
1.0
0.36
25.40
2.86
1.27
D-5
-------
allow for increased exposure levels Cor shorter exposure times. Such a trade-
off is given by Table D-l for 8-hr and 1 min exposures. For other exposure
times and for the concept of a vibration dose, the basic standard should be
consulted. For occupational and recreational situations, the values of Table
D-l can be raised by a factor of 3.15 (10 dB) to predict the boundary at which
working efficiency may start to decrease. Increasing the acceleration listed
in Table D-l by a factor of 6.3 (16 dB) will give the boundary necessary for
the preservation of health and safety. Thus the 1 min values of Table D-l
as multiplied by a factor of 6.3 provides the maximum recommended continuous
acceleration to which an individual should be subjected. However, assessment
of acceleration above the comfort levels listed in Table D-l should be made
only by direct reference to the ISO standard. In the ISO standard there are
many considerations and limitations with respect to human exposure Co acceler-
ation that can cause reduced efficiency or health and safety problems.
D.3. Vibration criteria for occupants in buildings. (Summary of 1980
draft addendum 1 to ISO Standard 2631-1978, and modifications as contained
in ANSI S3,29, Draft Standard Guide to the Evaluation of Human Exposure
to Vibrations in Buildings.)
D.3.1 Scope
The proposed standard takes into account the following factors:
m
1.	Type of Excitation - for example transient (shock) and/or steady
vibration;
2.	Usage of the Occupied Space in Buildings - for example, hospital
operating theatres, residential, offices and factories;
3.	Time of Day;
D-6
-------
4. Limits of Acceptability - in a proposal of this type there is no
hard and fast line of acceptability, but guidance is given as to
the level of complaint to be achieved at different levels of vibra-
tion. In cases where sensitive equipment or delicate operations
impose more stringent limits than human comfort criteria, then the
more stringent criteria should be applied,
D.3,2 Characteristics of building vibration
D.3.2.1 Direction of vibration
Because a building may be used for many different activities, standing,
sitting and lying may all occur, and hence, vertical vibration of the building
may enter the body as either Z axis, X axis or Y axis vibration, as shown in
Figure D-l. The Standard is written for all three axes of vibration. How-
ever, in cases where it is not clear which direction to apply, it is often
more convenient to consider the combined Standard detailed in Sections D.3.3.4
below.
D.3.2.2 Random or multi-frequency vibration
Random or multi-frequency vibration represents a particular problem
which fortunately does not often occur in buildings. There is evidence from
research concerning the building environment to suggest that there are inter-
action effects between different frequencies of vibration. Under these
circumstances and for random vibration, the proposed standard recommends an
overall weighting method such as that in section D.3.3.4.
D.3.2.3 The characterization of impulsive shock and intermittent vibration
Continuous vibration of a repetitive nature is easy to identify and
classify. The borderline between impulsive shock and intermittent vibration
D-7
-------
is difficult to define. Impulsive shock is characterized by a rapid build-up
to a peak followed by decay, and is typically excited in buildings by blast-
ing, forging presses or pile driving using an impact device. Intermittent
vibration may only last a few seconds, but is characterized by a build-up to a
level which is maintained for a considerable number of cycles. Examples of
this in buildings would be traffic excited vibration and vibration generated
inside a building by machinery starting up or on intermittent service. Pile
driving by modern methods using vibrating columns would also be classified as
continuous or intermittent vibration and not as impulsive shock.
The proposed standard recommends that impulsive shock created by forging
presses or conventional pile drivers should be treated in a similar manner
to continuous and intermittent vibration. Research has shown that vibration
which only occurs at a specific instance, for example domestic building
vibration by a passing bus, causes the same level of annoyance as continuous
vibration.
Blasting which occurs only up to three times per day is a special case.
The proposed standard recommends that building operations of this nature
should never take place at night due to the disturbance and that during
the daytime they should be limited to a small number of occurrences. The
levels of vibration generated due to blasting are on an order of magnitude
greater than traffic and general building vibrations, and can only be accepted
on the basis of very limited exposure.
D.3.2.4 Classification of buildings and building areas
The criteria of classification in the standard are derived from expecta-
tions of human reaction to vibration. In the home the highest standards are
required, and this is characterized by an absence of detectable vibration.
D-6
-------
Under other conditions, such as offices and factories, there is some tolerance
to vibration disturbance.
In the proposed Standard no differentiation has been made between differ-
ent types of residential areas, i.e. city centre, urban or rural. It ia
considered that similar standards should be met for all occupants of residen-
tial property. Some types of areas have not been classified, i.e. restaurants
or places of entertainment, but common sense suggests the most appropriate
classification—for example standards in a restaurant should be similar
to those in residential property. It should be noted that certain entertain-
ment areas in long span buildings present particular problems from self-
generated vibration, such as that from dancing.
Hospitals have not been given more restrictive levels in general because
there is some evidence that patients prefer to be in touch to some extent with
the outside world, but operating theatres and laboratories should be con-
sidered as critical areas.
D.3.2.5 Measurement of vibration
The use of "root mean square" acceleration is recommended as the standard
unit of measurement. If possible building vibration should be measured in
acceleration terms, but in some cases it may be found necessary to measure in
velocity or displacement due to equipment limitations. For these situations
the vibration should be treated as sinusoidal and the appropriate correction
f ac tors j wh x. c h ar e a functxon of frequency^ used to tr an s form either, the me a—
surement or the standard into compatible units.
In the case of impulsive vibration or shock the instantaneous peak value
of velocity or acceleration is the preferred unit of measurement. A trace of
the vibration should be obtained upon a suitable instrument and the peak level
0-9
-------
estimated. The motion should then lie considered sinusoidal and the correction
factors applied for the difference between peak and rms, and the frequency
dependent factors used to transform either measurement or standard into com-
patible units.
If frequency analysis of the vibration is required, third octave filters
are recommended. In certain circumstances it may be useful to analyze the
vibration in terms of narrow fixed band width filters.
Measurement of vibration should be taken on the floor at the point of
greatest amplitude, commonly found at mid-span. This should be close to the
point of entry of vibration to the human subject. Measurement should be
taken along the three orthogonal axes, and reference made to the appropriate
human axis standard to determine whether limits have been exceeded. Alter-
natively the weighting network or combination curves (see Section D.3.3.4)
could be considered in relation to the worse case found.
In the case of impulsive shock caused by blasting, measurement may be
made at the foundations to check for structural damage. It is also necessary
to measure according to the technique given above in the areas of human
habitation.
D.3.3 Characterization of building vibration and acceptable limits
D,3.3.1 Acceptable limits
A11 the foilowing proposals are related to the recom^sendatxocis for
general vibration on humans given in Section D.2. The presentation of infor-
mation is in the form of a basic rating which is given for the most stringent
conditions. From this basic rating a multiplication factor is then applied
according to the tables for other more permissive situations.
D-1Q
-------
The lowest basic rating has been defined in the area of the threshold
of human perception. It is based upon research work completed up to the end
of 1975.
Experience has shown in many countries that complaints of building
vibrations in residential situations are likely to arise from occupants
if the vibration levels are only slightly in excess of perception levels.
I
In general, the limits are related to the acceptance by the occupants and
are not determined by any other factors such as short-term health and work
efficiency. Indeed the levels are such that there is no possibility of
fatigue or other vibration induced syndromes.
D.3.3.2 Head to foot ("Z" Axis) vibration limits
For Z axis the recommended vibration values proposed by the standard is
shown in Figure D-2, For frequencies between 4 Hz and 8 Hz the maximum accel-
eration (rms) is 5 x 10"^ m/s^. At frequencies below 4 Hz the limit changes
at 3 dB/octave. For frequencies greater than 8 Hz the limit increases by 6
d3/octave. For conditions other than the base curve a series of weighting
factors apply and these are given in Table D-2. For example, for residential
property the weighting factor is two, hence at 4 to 8 Hz the maximum recom-
mended ras acceleration for residential property by day would be 10"^ m/s^.
D.3.3.3 Side to side or front to back (X or Y axis) vibration limits
For X and Y axis human vibration a different base curve applies which is
shown in Figure D-2. For frequencies from 1 - 2 Hz a maximum acceleration
level of 3.6 x 10 m/s will apply. At frequencies higher than 2 Hz the
acceptable acceleration level will increase at 6 dB/octave. This means that
for frequencies greater than 2 Hz a maximum rms velocity limit applies.
D-ll
-------
0.06
0.06
0.5 :
0.4
0.3
0.2
at
0.08
£
0.06
z
Iff
E
z
o
0.02
t-
<
£E
Ui
u
o
<
0.01
Z AXIS
0.008
0.006
_ X,Y AXIS
0.004
0.0036
0.003
COMBINED WORST CASE X,Y CR Z AXIS
dashed line is proposed weighting function _
0.002
0.001
2 3 4 5 6 789
20
40 60 SO
FREQUENCY (Hz )
FIGURE Q-2. Building vibration criteria for occupants in buildings. All curves are for
hospital and critical working areas. See Table D-2 for proper scale factors.
D-12
-------
TABLE D-2 WEIGHTING FACTORS FOR ACCEPTABLE BUILDING VIBRATION


Continuous or
Impulsive Shock


Intermittent
Excitation with
Place
Time
Vibration &
not more than 3


Repeated
Occurrences per day


Impulsive Shock

Hospital operating
Day
1
1
theatre & critical



working areas
Night
1
1
Residential
Day
2
90*
(minimum


complaint
Night
1.41
1.41
level)




Day
4
128

Day
4
128
Office




Night
4
128

Day
8
128
Workshop




Night
8
128
Weighting Factors above basic level of Curve shown in Figure D-2
~Modified per proposed ANSI S3.29—198X, Draft ANSI Standard Guide to the
Evaluation of Human Exposure to Vibration in Buildings,
D-13
-------
It will be noted that the standard for X or Y axis vibration is more
severe than the Z axis case at low frequencies. This is due to the sensi-
tivity of the human body towards away at these low frequencies,
The table of weighting factors given in Table D-2 also applies to
X or Y axis vibration.
D.3,3.4 Combined standard - recommended limits for undefined axis of human
vibration exposure
D.3.3.4.1 Worst case combination curve
In many situations the same building area may be used in both the lying
and standing positions at different times of the day. If this is the case,
then a combined Standard using the worst case combination of both the Z
axis and X and Y axis conditions may be applied. This combination curve is
shown in Figure D-2 and the same weighting factors given in Table D-2 still
apply.
D.3.3.4,2 Proposed weighting network
The proposed standard also recommends a weighting network that closely
approximates the combination curve. For routine measurement and evaluation
of environmental vibration, this frequency weighting is recommended. The
weighting function proposed for combined or random vibrations is given by:
G (Jw) =¦ -j			
v ' 1 + J w
11.2	Eqn D-l
where G (J w) is the transmissibility of the filter, J represents the square
root of -1, represents the exciting frequency.
This mathematical expression defines the electronic weighting filter of
the low pa3S type. At low frequencies the transmissibility i3 zero, and at
D-l 4
-------
high frequencies attenuation is at 6 dB/octave. The corner frequency is 5.6
Hz .Ac curacy - _+ 0.2 dB
Although the proposed standard recommends this function for preliminary
investigations, for practical evaluations of the overall environmental impact
of vibration on a community, the weighting function is a necessary and useful
simplification, especially with respect to residential areas, that is not
expected to introduce any significant errors.
D.4. Structural damage from building vibration. (Summary of 1976 draft
Standard ISO/TG 108/SC 2/WG3
D.4.1 General considerations
The proposed standard discusses the following general considerations:
Vibration in buildings (dwellings, offices, public buildings and factories)
is of increasing general importance, especially since the distances between
industrial areas with vibration exciting machines, blasts or other vibration
sources and residential areas are decreasing. Traffic on roads and railroads
also causes vibration troubles in nearby buildings.
Various methods of rating the severity of vibration in buildings and
defining limits based on laboratory or field data have been developed in the
past. However, none of these methods can be considered applicable in all
situations and consequently none have been universally accepted.
In view of the complex factors required to determine the response of a
building due to vibrations and in view of the paucity of quantitative data,
this proposed Standard was prepared, first to facilitate the evaluation and
comparison of data gained from continuing research in this field; and, second,
to give provisional guidance as to the acceptable values in order to avoid the
D-15
-------
risk of damage. The limits proposed are a compromise of available data. They
satisfy the need for recommendations which are simple and suitable for general
application. These limits are defined explicitly in numerical terms to avoid
ambiguity and to encourage precise measurement in practice.
If the characteristics of the excitation vibration are known in relation
to the severity, position and direction of the building response—this may be
the case if the source of the vibration is within the building—and if the
parts of the buildings or the whole building influenced by the vibrations can
be idealized by a model, then it may be possible to estimate the severity of
the dynamic stresses by calculation.
If vibrations are transmitted via the ground and the foundation into a
building, it may be possible to estimate dynamic stresses based on vibration
measurements.
In addition to simple vibration there may be other factors which influ- ,
ence vibration response (foundation coaditions, dilatation due to temperature
etc.) and which result in damage to buildings. No general method exists at
present to take account into all such factors.
D.4.2 Categories of damage
The proposed standard provides several phases of damage which can occur,
namely:
Category 1:
Threshold damage consists of visible cracks in non-structural members such
as partitions, facings, plasterwalIs (e.g. loosening of mortar between pan-
tiles etc.). As a guideline visible cracks may be taken as those of a width
of 0.02 mm.
D-16
-------
Category 2;
Minor damage consists of visible cracks in structural members such as
masonry walls, beams, columns, slabs and no serious reduction in load carrying
capacity.
Category 3:
Major damage consists of large permanent cracks in non—structural and
structural members; settlement and displacements of foundations which may
result in reduction of load carrying capacity.
The proposed standard applies chiefly to damage as described in cate-
gories 1 and 2. The limits of vibration specified in the standard were
selected to avoid the exceeding of the threshold of damage, but does include
data for estimating damage levels.
D.4.3 Measurement
D.4.3.1 Frequencies
The proposed standard recommends the following frequency ranges:
1,	In the case of vibration caused by shock and quarry blasting and
the steady vibration of whole buildings: from about 1 Hz to about
100 Hz.
2.	In the case of steady vibration of parts of a building, especially
floor and wall vibrations: from about 10 Hz to about 100 Hz.
D.4.3.2 Measurement points
The standard recommends that vibration caused by shock, especially
quarry blasting, should be measured on the foundation structure parallel
to its stiff-axes below ground level.
D-17
-------
In only special cases are measurements of floor vibration in the vertical
direction and the horizontal vibration of the whole building recommended.
Such floor vibration measurements should be made in a manner similar to that
of section D.3.
In the case of steady vibration (e.g. floor vibration), the vibration
peak velocity, vmax, at the place of highest amplitude should be determined.
In floor vibration it is often the midspan, for whole building vibration it is
often the upper floor in horizontal direction.
D.4,3.3 Measurement quantity
Vibration can be measured by displacement, velocity or acceleration. It
is desirable to measure the quantity that is most simply and generally related
to damage as described below. While for steady vibration the proposed standard
provides curves related to velocity from 10 Hz to 80 Hz (Figure D-3), it can
be seen that for the frequency range of 10 to 80 Hz, acceleration as weighted
by the function in Chapter 3 is for all practical purposes a measure of velo-
city. Plotting the weighted acceleration against actual blast damage data, see
Figure D-4, the weighted acceleration provides a very reasonable fit to the
data for frequencies below 10 Hz. For these reasons, the use of the weighted
acceleration is proposed in the main sections of these guidelines for assess-
ment of impact due to annoyance of building occupants and building damage.
For shock the proposed standard recommends using the vector sum of the
maximum velocity along a set of orthogonal axes. The maximum velocity along
an axis is that measured at any time during an event. Such an approach will
be slightly more conservative than only using the maximum weighted acceleration
along the worst case axis. However, the differences between the two approaches
D-18
-------
\U
Z
w
o
<
_»
a
«
6.3
5,0
3.2
2.5
2.0
1.25
1
T
\%%\
0.8
0.63
0.5
0.4
0.32
0.25
0.2
0.16
0.125
0.1
0.08
.063
0.05
0.04
0.032
0.025
0.02
0.016
0.0125
0.01
0.008
0.0063
0.005
0.004
0.0032
0.0025
0.0020
%%
WEIGHTED ACCELERATION BASED ON
ACCELERATION At tOMi OF O.Sm/,2
WEIGHTED ACCELERATION BASED ON
ACCELERATION AT 3Hi OF O.Sm/,2
V
\ Q

lOmm/j
6 mm/.
2.5n,™X%
•c
I M I I
I M I I I t I I I I
I I.6 2.5 4 6.3 10 16 25 60 63 tOO
125 2 32 5 8 12.5 20 32 50 90
FREQUENCY (Hi)
FIGURE D-3. Rough evaluation of vibrations of stationary floor vibrations by measurement
of vibration displacements amplitude and frequency
Note: Amplitude is defined here as the maximum absolute value of the displacement
of the floor undergoing harmonic motion.
D-19
-------
Weighted Accelerations of 1 meter/sec^
1. \
*«•. *« *
* 0.06
M 0.02
0.01
0.008
0.006
0.004
0.002
0.001
- CV? *0 A \ t\/'
• V.	« Jr
*- ^	K
i
Weighted Accelerations of 0.5 meter sec.'
Major damage v ¦ 7.6 in/sec.
Minor damage v a 5.4 in/sec.
a
Safe blasting criterion
v = 2.0 in/sec
o Bureau of Mines
o Langefors
A Edwards and Northwood
• Bureau of Mines
¦ Langefors
A Edwards and Northwood
	i	I	L_
.o •

V OT3
Major damage data*'
Minor damage data
1
10
20
40 60
200
400 600
FREQUENCY, cps
FIGURE D—4. Displacement versus frequency, combined data with recommended safe blasting criterion
D-20
-------
is not expected to be great (at the maximum they can only differ by a factor
of the square root of 3).
D.4.4 Vibration boundaries with respect to damage categories
D.4.4.1 Vibration caused by shock
In determining criteria for the onset of vibration damage to buildings,
the proposed standard indicates a number of factors which can affect the
results which are recorded.
These include:
-	nature of the soil, clay, or rock, etc.
-	stiffness of the building structure
-	nature of the vibration, i.e. transient, intermittent, continuous, vertical,
horizontal, etc.
With these uncertainties in mind, the proposed standard provides recom-
mendations as to the maximum velocity to prevent damage for each of the three
categories. These velocities are listed in Table D-3,
TABLE D-3
Limiting values of the vector sum of the maximum velocities (in three ortho-
gonal axis) caused by quarry-blasting-vibration in dwellings and offices in
good physical conditions
Category of Damage	range V^, onset of
(See Section D.4.2)	damage, in mm/a
1	3 ... 5
2	5 ... 30
3	100
These values are based on measured foundation vibration in the
frequency range from about 3 Hz to about 100 Hz.
D-21
-------
The standard cautions that:
(1)	In the range between 30 mm/s and 100 mm/s the available data is
not sufficient to define the nature of the damage without regard
to the condition, type of structure and foundations.
(2)	The limits apply only where differential settlement of the structure
has not been excessive,
(3)	Special consideration shall be given where buildings are situated
on a slope or on soils which may be compacted or liquified by
vibration.
(4)	When large dynamic displacements are found to exist in the whole
building or part of it then in addition to the recommended measuring
points at the foundation additional measuring points located in
the structure shall be used for the evaluation of potential building
dama ;e.
The standard recommends that the limits specified in Table D-3 be used
for the evaluation of vibration effects caused by pile drivers and forging
hammers when the time interval between two successive blows i3 so large
that the vibration of the building due to one blow dissipates before the
effects of the succeeding blow are observed. Dissipation is regarded as
effective when peak particle velocities have decayed 1/5 from their maximum.
The standard proposed that the values specified in Table D-3 may also be
used to evaluate the effects of vibration in buildings caused by traffic;
however, when shakers and vibration pile drivers are the source of building
vibration, the values given in Table D-3 should not be applied.
Finally, the standard recommends that for the evaluation of transient
response of floors «nd walls, the vibration limits given for steady state
D-22
-------
vibrations may be used in a modified form. When there is no danger of fatigue
the limits and values given in Figure D-3 may be increased by a factor of 2.
D.4.4.2 Steady vibration of buildings
For steady building vibration, Figure D-3 summarizes the peak velocity
boundaries between the different categories of damage.
0,4.5 Comparison of the recommendation of the proposed standard to the
recommendations of these guidelines
The proposed standard recommends that 6 mm/s C5 to 30 mm for shoclc^ be
considered as the upper limit of the threshold of damage. These velocities
are considerably lower than the 2 in/sec (50.8 mm/sec) that has commonly been
used in this country. Based on studies such as those shown in Figure D-4,
reducing the threshold from 50 mm/sec to 5 am/sec does not appear warranted,
however, reduction of the threshold by «. factor of 2 does seem reasonable.
All of the data points of Figure D-4 will be covered by use of a velocity
of 1 in/sec and it is this velocity that is recommended in the main text of
the guidelines. Use of a weighted acceleration of 0.5 m/sec^ is consistent
with this velocity and is recommended.
D-23
-------
-------
APPENDIX E
EXAMPLE APPLICATION OF THE GUIDELINE PROCEDURES FOR
GENERAL AUDIBLE NOISE
E.1 Proposed highway expansion
This example (presented briefly in section 2.6) concerns a section
of highway which runs for several kilometers through a suburban area (Figure
E-l). The present two lane roadway is operating at close to capacity, and
the proposal is to expand it to six lanes. Although many factors must be
considered before undertaking such an expansion, only the noise impacts of
the project will be discussed as an illustration of the use of these Guide-
lines. This example is divided into five sections as follows:
(1)	Statement of the problem
(2)	Using the screening diagram
(3)	Determining the necessary number of figures and tables
(4)	Completing the figures and tables
(5)	Conclusions of the noise analysis
E.l.l Statement of the problem
From Figure 2 in section 1.3.1, it has been assumed for the purposes
of this example that the only concern is general audible noise that may cause
an adverse impact. That is, special noises, vibration, and changes in popula-
tion location are not anticipated to be problems. Tables 6 to 9 in section
2.6 document the project impact over the total area (Figure E-l}. However, to
illustrate in some detail the use of these Guidelines, this example focuses
on a small residential section only, as shown in Figure E-2. Each of the
residential buildings consists of two semi-detached townhouse units, with an
average population of five persons in each unit, or SO persons in each row of
housing. Additionally, there are four special situations to be considered:
E-l
-------
HIGHWAY
School /
Microarea
covered in
Highway
Example
RESIDENTIAL
RESIDENTIAL
COMMERCIAL
1 School
Play-
ground
POPULATION:
550
Park
Nursing
Home
Church
School
COMMERCIAL
INDUSTRIAL
FIELD
] Library
FIGURE E— 1. Highway Expansion Example: Overview
^ Area for ihe
^ specific example
-------
M
I
u>
Ldn(y)
I
70dB
65dB
60dB
RESIDENTIAL
55dB
t
SOdB
0.5km *-
-tS
[O
£~
-03-
f5 I
(~
EZJ
(O
(ED
{HZ3

[=~
[=~
-B-
c=i
CZ)
i—i
~
CZ3
~
~
2 Lanes
-EE3-
[=~
-S-
EZZ!
EU
(=~
~
CZ1
FECIAL
...iTUATIQflS

J: 25
EZ1
GEZ3
to***
150
EZI
EZI
lB 1 375
£=~
QE
JnZ3 _
Total Population: 550
•4.14km
b^nrrtTiTn! m

SCHOOL
PLAYGROUND

PARK
CHURCH
Figure E-2. Sample Data Presentation for the Highway Example: Future Levels Without the Proposed Project
-------
(l)a school with a student-teacher population of 2,500 in attendance 50 weeks
a year from 8:00 a.m. to 4:00 p.m.; (2) a playground where 400 children play
six hours each day; (3) a park where 160 people relax for one hour each day;
and (4) a church where 185 people meet for two hours each day, and 115 people
meet for one hour each evening. For a larger project area (such as in Figure
E-l), this amount of detail normally would not be obtained. Noise contours
would still be plotted, but populations could be estimated from average
population densities, census counts, or other such sources as discussed in
section 2.1.3. The example is intended to provide an easy-to-follow descrip-
tion of the Guideline procedures.
E.1.2 Using the screening diagram
Is an environmental noise analysis necessary, and if so, what procedures
should be followed? Begin by examining the Screening Diagram (Figure E-3, and
discussed in section 2.1). This diagram is helpful for determining not only
whether a noise impact analysis is necessary, but also what type of analysis
should be conducted.*
E. 1.2.1 How to use the screening diagram. The values for the "existing
Ldn(y)" an<* the "expected of [the] project alone" should be obtained at
the location of the noise sensitive land use nearest the project, or the point
where the impact of the project is likely to be the greatest. In this example,
that point would be the row of duplexes closest to the highway. The existing
*For this example, it is not absolutely necessary to use the screening
diagram since it is more or less obvious that some increase in noise
will result, and at levels high enough for a full noise environment docu-
mentation. However, if in doubt, the screening diagram is a useful aid.
1-4
-------
Lit
<
f—
o
LL!
—3
o
cr
a.
c
X3
-J
Q
yy
H
Q
yy
£3L»
x
yj
70
60
50
FULL NOISE ENVIRONMENT
DOCUMENTATION FOR ALL
PROJECTS
X (60,65)
40
POSSIBLE NOISE
DEGRADATION
ANALYSIS

40
DOCUMENTATION
DEPENDS ON
FUTURE OF
EXISTING
NOISE SOURCES
ALL PROJECTS
SCREENED OUT
I
±
90
50 60 70 80
EXISTING Ldn{y)
Figure E-3. Screening Diagram: Sample Application
E-5
-------
^dn(y) aC the closest noise sensitive"point may be obtained either by direct
measurement or by use of a suitable traffic noise prediction model** as dis-
cussed in section 2,1.2. It ia assumed that future Ljn was obtained through
the use of a prediction model. Once the values of "existing L<|n(y)" and
"future Ldn" are obtained, they are plotted as coordinates on the screening
diagram (Figure E-3). Their point of intersection (for this example, 60 dB
and 65 dB)*** determines both the necessity for and type of noise analysis
that should be conducted. In this case, the coordinates fall into the cell
that calls for a full noise environment documentation. Therefore, a full
noise analysis should be conducted.
E.l.2.2 Other factors to consider before beginning the noise analysis.
As discussed in Chapter 2, there are a few other basic issues which should
be considered before beginning the noise analysis:
o How many projects or alternatives are we considering?
We are considering only one, an expansion from two to six lanes,
o Will the population of the residential area change in the future?
No, the population will remain the same (by assumption in this
example).
o Is this a temporary project, as defined in section 2.5?
No, this is a long-term project.
**There are in use several models for calculating day-night sound levels
based on the type of noise source and operational considerations. These
models are available from many sources, some of which are listed at the
end of this appendix.
***At the row of houses closest to the highway, the existing Ldn(y) 60
dB is from Figure E-2, and the predicted Ldn(y) o£ 65 dB from the project
alone (the 6-lane highway) is from Figure E-4.
E-6
-------
o Will the noise of the project change with time (after the completion
of the project)?
No, the noise of the project will remain the same. The immediate
demand for the added lanes will be sufficient to fill then to capacity
(by assumption in this example).
o Are existing noise levels in the area low enough that "environmental
degradation" is the only concern (as defined in section 2,4)?
No, most of the area will be exposed to project Ldn(y) greater
than 55 dB. This is confirmed by the screening diagram.
1,1,3 Determining the necessary number of figures and tables. Prom the
discussion in section 2,2.2.a, it is clear that only three sets of contours
and corresponding tables are required.*
o Future levels in the area without the project, i.e., future levels
from the existing highway and from residential activities,
o Future levels due to the proposed project alone, i.e., the six-
lane highway alone.**
o Future levels resulting when the levels from the six-lane highway
are combined with the levels generated by other noise sources,
i.e., in this case by residential area activities.
*As noted in the text, the population density within the residential area
is not expected to change, nor will the noise from the highway change
in years subsequent to the proposed expansion. Because these conditions
with respect to time are expected to remain constant, additional sets of
tables and figures are not necessary. However, if these conditions were to
change over time, separate sets of tables should be prepared for (a) the
first year of the commencement of the project, (b) twenty years after the
expansion (or the latest year for which noise predictions can be reliably
made), and (c) the worst case year (if different from the preceding two).
*"*Note that when the proposed action is an expansion of an existing noise
source, the proposed project alone is interpreted to be the expanded
project (that is, the six-lane highway), not the amount of expansion (in
this case, the additional four lanes).
E-7
-------
E.1.4 Completing Che figures and Cables
The purpose of Che analysis is Co compare Che future noise environment
with and without the proposed project. This comparison can be divided into
five steps; (1) drawing the noise contours, (2) determining the base area
and the base population, (3) transferring the data Co the tables, (4) calcu-
lating the single-number comparison indices; and (5) noting special popula-
tions,
E.1.4.1 Drawing the noise contours. As discussed in section E.1.3, three
sets of contours and tables are required. For purposes of this example, it
is assumed that contours describing the future noise environment in the area
without the highway expansion have been obtained by measuremenc, since in Chis
example future levels are the same as existing levels. It i3 also assumed
chat the noise levels from the future six-lane highway alone have been
obtained from a suitable hi hway noise prediction model. These results are
illustrated in Figures E-2 a .d E-4, respectively.
To draw contours reflecting the combined future noise environment from
the project levels and levels generated from residential activity requires
additional information, that is, knowledge of residential area levels in
the absence of any highway noise. This information can be obtained in two
ways. An estimate can be m*de on the basis of population density using
equation 1 in section 2.1.1. Or, measurements can be taken at a large dis-
tance from the road (for example, where noise from the roadway is no longer
clearly noticeable), as long as the nature of the area is not expected to
change in the future. The background residential noise levels derived above
(assumed to be about 50 dB in this example) are then combined on a point-by-
point basis with the project alone levels presented in Figure E-4 to derive
E-8
-------
M
v©
J
n(y)
70dB
I
65dB
60dB
55dB
50dB
| 4SdB
0.5km i	
¦G3-
lO
E=3
nm
dZJ
[O
O
EZ3
GUI
ElD
-E3-
CZI
CZZ3
L_j
CD
CZD
C=D
CZ3
C=D
CZ3
(ZD
RESIDENTIAL
6 Lanes
cm
¦Q-
czn
CD
(=~
tzzi
c=i
czi
(ZZl
~
CD
N
:SPECIAL
.¦situation
¦gZl * 25 i
nu
m i 'iBBmBiii
75
SCHOOL

50
: a.
•	Uv
i/
•	*DI ,
7#
PLAYGROUND
E=3
I
150
PARK
EZ3
CZI
I5 I
E
r?n
no
¦wans*:
3 i <<
250
CHURCH

4.74km :
Figure E-4. Sample Data Presentation for the Highway Example: Future Noise Levels from the Project Alone
-------
contours depicting the total future noise environment (project plus back-
ground) as shown in Figure E-5.*
E. 1.4.2 Determining the base area and base population. As noted in section
2.1.3, the base population is defined as the number of people living in
areas with outdoor noise levels produced by the project alone above a speci-
fied value. This is called the base L,jn. The base Ljjn is deter-
mined by reference to the existing yearly	contours in the residential
area (Figure E-2). The lowest Ljjn in the residential area is about 50 dl
near the back row of houses. Therefore, from section 2.1.3, the optimum base
Ljjj, to use, if possible, in order to define the base population is 40 dB
(that is, 10 dB below the existing Ldn(y)^* Next, we examine Figure E-4
which shows the noise contours from the project alone. Applying the base
Ldn 3 40 dB, we can derive the base area. In this example, none of the
residents are living in areas where the outdoor yeai'y day-night sound levels
are below 45 dB (i.e, no people live within the 40-4." dB interval). Thus, the
next best thing is to effectively define the base area as the area exposed
above I
-------
RESIDENTIAL
6 Lanes
PECIAL
...!.TUA7'.QfilS
n—I
[=~
CZI
50

Ir.'irr? jp-=ry ¦arrrrtriirf
frHutjlT
SCHOOL
lO
-tEEJ-
EZ3
fs—I
-H3-
£~
O
E=D
ED
1=]
¦B
C=)
en
-B-
C=J
CD
CZD
~
C=D
CZI
¦B
[=~
HZ]
CZD
[ZD
~
CZ3
E=1
-G3-

75
Qj
z
7^
PLAYGROUND
EZ1
150
mi'
PARK
B
EZ1
1B I 275
HZ3
ho 1
EO
CHURCH
4.74km
Figure E-5. Sample Data Presentation for tha Highway Example: Future Levels from All Noise Sources Combined
-------
contour line bisected a row of duplexes, the residents were divided between
the noise bands. For example, from Figure E-5:
Noise band (L(jn^yj)	Number of People
65 - 70 dB	50
60 - 65 dB	75
55 - 60 dB	150
50 - 55 dB	275
E.l.4.4 Calculating the single-number indices. For this comparison! three
measures of impact should be considered: (1) the sound level weighted popula-
tion (LWP)j (2) the noise impact index (Nil); and (3) the relative change in
impact (RCI) .* The indices LWP and Nil should be computed for each of the
tables (Tables E-l thru E-3). For purposes of illustration, detailed calcula-
tions will only be shown for Table E-l.
Calculation of the level weighted population was based on the values of
the weighting function of equation 2b, shown in Table 3 of the main text.
Thus, using equation 6:
LWP - [P(65—70> x W(67.5)] + [F(60-65) x W(62.5)] +
[P(55-60) x W(57.5)] + [?(50-55) x W(52.5)] +
iP(45-50) x W(47.5)]
- t(0) x (0.194)] + [(25) x (0.116)] +
C(150) x (0.064)] + [(375) x (0.032)3 +
[(0) x (0.015)]
* 24.5»24 people
*In this example, since there are no outdoor exposures greater than L,jn * 75
dB, it is extremely unlikely that there will be any at-ear l*eq(24) exposure
greater than 70 dB. Therefore, we need not consider the single-number
indices for severe health effects (hearing-loss weighted population and
average potential hearing loss) as discussed in section 2.3.
E-l 2
-------
TABLE E-l
SAMPLE DATA PRESENTATION FOR THE HIGHWAY EXAMPLE: FUTURE LEVELS WITHOUT PROPOSED PROJECT
Industrial/
Residential Commercial	Special
Residential	Land Area	Land Area	Total Land	Situations
Yearly L,jn (dB) Population	(Sq km)	(Sq km)	Area (Sq km)	(See Table E-4)
>70
0
0
0
0
—
65-70
0
0.087
0
0.087
-
60-65
25
0.107
0
0.107
-
55-60
150
0.646
0
0.646
1,2
50-55
375
1.530
0
1.530
3,4
45-50
0
0
0
0
-

550
2.370

2.370

Level Weighted Population (LWP) = 24
Noise Impact Index (Nil) = 0.044
Hearing-Loss Weighted Population (HWP) = 0
Average Potential Hearing Loss (PHL) = 0
Corresponds to Fig. E-2
Includes: o Self-generated
neighborhood noise.
o Levels of noise from
the existing two-lane
highway.
-------
TABLE E-2
SAMPLE DATA PRESENTATION FOR THE HIGHWAY EXAMPLE: FUTURE NOISE LEVELS OF PROJECT ALONE
Industrial/
Residential Commercial	Special
Residential	Land Area	Land Area	Total Land	Situations
Yearly L(jn (dB) Population	(Sq km)	(Sq km)	Area (Sq km) (See Table E-4)
>70
0
0
0
0
—
65-70
25
0.1232
0
0.1232
-
60-65
75
0.2702
0
0.2702
1
55-60
50
0.2465
0
0.2465
2
50-55
150
0.3982
0
0.3982
3
45-50
250
1.3320
0
1.3320
4

550
2.370

2.370

Level Weighted Population (LWP) = 25
Noise Impact Index (Nil) = 0.045
Hearing-Loss Weighted Population (HWP) = 0
Average Potential Hearing Loss (PIIL) = 0
Corresponds to Fig. E-4
Includes: o Levels of noise
from the proposed
six-lane highway.
-------
TABLE E-3
SAMPLE DATA PRESENTATION FOR THE HIGHWAY EXAMPLE: FUTURE LEVELS FROM ALL NOISE SOURCES COMBINED
Residential
Residential	Land Area
Yearly Ljn (dB) Population	(Sq km)
>70
0
0
65-70
50
0.1232
60-65
75
0.2465
55-60
150
0.6716
50-55
275
1.3830
45-50
0
0

550
2.370
Level Weighted Population (LWP) = 37
Noise Impact Index (Nil) = 0.067
Hearing-Loss Weighted Population (HWP) = 0
Average Potential Hearing Loss (PHL) ¦= 0
Industrial/
Commercial	Special
Land Area	Total Land	Situations
(Sq km)	Area (Sq km)	(See Table E-4)
0	0
0	0.1232	1
0	0.2465	1,2
0	0.6716	3
0	1.3830	4
0	0
2.370
Corresponds to Fig. E-5
Includes: o Self-generated
neighborhood noise,
o Levels of noise
from the six-lane
highway.
-------
The Noise Impact Index, according to equation 7 in section 2.2.2.C, is
simply LWP divided by the total (base) population. Thus:
LWP 24
Nil - -==£¦		 — ¦ 0.044
^Total
From equation 8, the Relative Change in Impact between the case without
the proposed expansion (Table E-l) and the case with the expansion (Table E-3)
is computed as:
RCI -	~ LWPb » 37 " 25 » 48%
LWPb	25
E.l.4.5 Noting special populations. Special populations do not affect the
calculation of the single-number indices. However, they are noted on the
figures and tables to give the reader additional information about the affec-
ted area. As discussed in Section 2.2.2.a., the time weighted average number
of people present at these special locations during the year may be computed
as;
(number of people) x (time the people are present during the year)
(number of hours in a year)
For the school in our example where 2,500 students and faculty use the school
eight hours a day, five days a week, forty weeks a year:
(2,500 student and teachers) x (8 hours) x (5 days) x (40 weeks) m
8,760 hours in a year
For the playground where 400 children play six hours each day:
(400 children) x (6 hours) x (7 days) x (52 weeks) _ people
8,760 hours in a year
For the park where 160 people relax for one hour per person each day:
(160 people) x (1 hour) x (7 days) x (52 weeks) ^ , »
8,760 hours in a year	p p "
E-16
-------
For the church where 185 people meet for two hours each day, and 115 people
meet for one hour each night, consider the day and night population separately;
(185 people) x (2 hours) x (7 days) x (52 weeks) m . _ .
8a/n .	•	* J people •
,760 hours m a year
(115 people) x (1 hour) x (7 days) x (52 weeks) _ r
	c—c	fTfW		 5 people.
The results for special populations are depicted in Table 1*4,
E-17
-------
Elementary school
School playground
Park
Church
TABLE E-4
SAMPLE DATA PRESENTATION: SPECIAL SITUATIONS
Average population
Day
457
100
7
15
Night
0
Range of Ldn(y)
Current	Future with Project
55-60 dB
0	55-60 dB
0	50-55 dB
5	50-55 dB
60-70 dB
60-65 dB
55-60 dB
50-55 dB
Comments
Good acoustic
insulation
Evening meetings
-------
E.2 Proposed airport runway addition
This example concerns the addition of a runway at an angle to an existing
runway. The additon will be completed in 1985. After 1985, airport operation
and noise will increase until maximum levels are attained in 2001. Bordering
the airport are a high and a low population density neighborhood. Both neigh-
borhoods will encroach on the airport between 1985 and 2001, as is shown
in Fig. E-6, The rest of the land near the airport is zoned commercial/
industrial. Although many factors must be considered before undertaking an
airport expansion, only the noise impacts will be discussed in order to
illustrate the use of the Guidelines.
This example is divided into five sections:
(1)	Statement of the problem
(2)	Using the screening diagram
(3)	Determining the necessary number of figures and tables
(4)	Completing the figures and tables
(5)	Conclusions of the noise analysis
E.2.1 Statement of the problem
From Figure 2 in section 1.3.1, it has been assumed for the purposes of
this example that the only concern is general audible noise that may cause an
adverse or potentially severe impact. That is, special noises and vibration
are not anticipated to be problems. To illustrate in some detail the use of
these Guidelines, this example focuses on the potential noise impact upon each
of the residential areas in proximity to the airport as shown in Figure E-6.
It is assumed that the number of people living within each of these neighbor-
hoods is computed or estimated from census counts, average population den-
sities or other methods discussed in section 2.1.3.
E-19
-------
HIGHWAY
POPULATION: 68.201
POPULATION: 31,689
POPULATION: 31,689
HIGH DENSITY
NEIGHBORHOOD
GROWTH OF
NEIGHBORHOODS
LOW DENSITY
.NEIGHBORHOOD
ORIGINAL RUNWAY
laww" Mffgrro ^
MAXIMUM USAGE AND NOISE LEVELS: 2001
COMPLETION DATE: 1966
PRESENT
FigureES. Sample Data Prstanlalion for (ha Airport Example: Schematic of the Existing Situation, 198S, and 2001.
(Note the Addition of the Project Runway and the Encroachment of the Neighborhoods..)
-------
E.2.2 Using the screening diagram
Is an environmental noise analysis necessary, and if so, what analytical
procedures should be followed? Begin by examining the Screening Diagram
(Figure E-7 and explained in section 2.1). This diagram is helpful for
determining not only whether a noise impact analysis is necessary, but also
what type of analysis should be conducted,*
1.2,2.1 How to use the screening diagram. The values for the "existing
^dn(y)" an<* the "expected L,jn of [the] Project Alone" should be obtained
at the location of the noise sensitive land used nearest the project, or the
point where the impact of the project is likely to be the greatest. Relevant
noise level data is contained within Figures E-8 and 1-9 , respectively.
Because, as previously noted, airport n >ise will be greatest in the year 2001,
the point of greatest impact is taken ~rom Figure E-9. In this example, the
point where the impact of the project likely to be the greatest is in the
high population density neighborhood, and is designated on Figure E-9 by the
mark "X". The Ldn(y) at that location from the airport alone will be about
81 dB.** Note that, in this example, the point of Greatest impact is not
*For this example, it is not absolutely necessary to use the Screening
Diagram since it is more or less obvious that some increase in noise will
result, and at levels high enough for a full noise environment documenta-
tion. However, if in doubt, the screening diagram is a useful aid.
**The "Future Noise Levels of Project Alone; 2001" (Fig. E-9) was determined
by using a computer model, as discussed in section 2.1.2. There are
several models for calculating day-night sound levels based on the type
of noise source and operational considerations. These models are available
from many sources, some of which are listed at the end of this appendix.
These models were also used to predict all of the other future L
-------
X (58,81)
DOCUMENTATION
DEPENDS ON
FUTURE OF
EXISTING
NOISE SOURCES
FULL NOISE ENVIRONMENT
DOCUMENTATION FOR ALL
PROJECTS
LLI
U.
J3 50
Q
UJ
ALL PROJECTS
SCREENED OUT
POSSIBLE NOISE
DEGRADATION
ANALYSIS J
HI
40
EXISTING Ldn
-------
INCLUDES:
•	NOISE FBCMTW HIGHWAY
•	SELF-GENERATED NOISE FfWM
BOTH NEIGHBORHOODS
•	NOISE FBOMTHE ORIGINAL RUMWAY
CORRESPONDS TO TABLE E-5
1km
t»»»»•»««*•••
«#»*»*••»***•
A • * • 4 0 B 0-*>• **41
• * *.**%%*%%•%*
Figur* E-8. Sampb 0»ta Prestation for tiw Airport Example: Exerting ldt,
-------
INCLUDES: • NOtSE FROM BOTH ORIGINAL 65
AND PROJECT RUNWAY
S
CORRESPONDS TO TABLE E-6



.mSm%««*«««¦
«Mk
«#4 ««•««*•#•
*«*««*««««*
¦ rn" ¦»•««*»<••**••¦
		
1 km
M
65
\
Figur* E-9. Samqto Data PraMnntion for th« Airport Exampla; Future Noija Leveli of th« Project Along; 2001
E-24
-------
the closest noise sensitive location. The noise level at the corresponding
point on Figure 1-8 is approximately 58 dB»*
Once the values of the "Existing Ldn(y)" an(* the "Expected Ldo of the
Project Alone" are obtained, they are plotted as coordinates on the screening
diagram (Fig. 1-7). Their point of intersection (for this example, 58 dB and
81 dB) determines both the necessity for, and type of, noise analysis that
should be conducted. In this case, the coordinates fall into the cell that
calls for a full noise environment documentation. Therefore, a full noise
analysis should be conducted.
E.2.2.2 Other factors to consider before beginning the noise analysis. As
discussed in Chapter 2, there are a few other basic issues which should
be considered befori beginning the noise analysis:
o How many projects are we considering?
We art considering only one option, the addition of a runway
with an increase in total airport operations,
o Will the population of the residential areas remain the same?
No, between the years 1985 and 2001 both residential areas
will increase in population and size. In the existing situation,
the self-generated (ambient) noise levels in the low density
neighborhood (780 people per square kilometer) is estimated
to be 55 dB. By assumption, the number of people in the low
density area will remain the same until 1985. By the year
2001, even though the population will increase, the ambient
*For purposes of this example, the "Existing ^^(y)" (Fig. E-8) was assumed
to have been determined by direct measurement as discussed in section 2.1.2.
E-25
-------
noise levels* will remain the same because the population
density (people per square kilometer) will remain constant.
In the high density neighborhood, the existing and future ambient
is estimated to be 65 dB (7,700 people per square kilometer),
o Is this a temporary project, as defined in section 2.5?
No, this is a long-term project,
o Will the noise of the project change with time (after the
completion of the project in 1985)?
Yes, as previously stated, the noise levels will be increasing
between 1S85 and 2001, reaching a maximum in the year 2001.
The increase in noise is caused by an increase in airport
operations.
o Are existing noise levels in the area low enough that "environ-
mental degradation" is the only concern (as defined in section
2.4)?
No, surrounding the airport is a commercial/industrial area with
a background I
-------
E.2.3 Determining the necessary number of figures and tables
From the discussion in section 2,2.2.a, it is clear that a number of
sets of contours and corresponding tables are necessary,
o Existing noise levels
o Future levels without proposed project; 19B5
o Future levels with the proposed project alone; 1985
o Future levels from all noise sources combined; 1985
o Future levels without proposed project; 2001
o Future levels with the proposed project alone; 2001*
o Future levels from all noise sources combined; 2001
E.2.3.1. Completing the figures and tables. The purpose of the analysis is to
compare the future noise environment with and without the proposed project.
This comparison can be divided into four steps: (1) drawing the noise
contours; (2) determining the base area and the base population; (3) transfer-
ring the data to the tables; and (4) calculating the single number comparison
indices.
1.2.3.1 Drawing the noise contours. As discussed in section 1.2.3, a number
of sets of contours and tables are necessary. For purposes of this example,
it is assumed that the future noise levels of the project have been obtained
from a suitable airport noise prediction model taking into account the new
generation of quieter aircraft. To draw contours reflecting the combined
future noise environment from the project levels and levels generated from
*Note that when the proposed action is an expansion of an existing facility,
the proposed project alone is interpreted to be the expanded project (that
is, both the old and new runways), not the expansion alone (in this case,
the new runway alone).
E-27
-------
residential activity requires additional information. A knowledge of residen-
tial area levels in absence of any other noise (such as highway or airport
noise) is necessary. This information can be obtained in two ways. An
estimation can be made on the basis of population density using equation 1
fran section 2.1.2, or measurements can be taken at a large distance from
the other noise sources. In this example, the former method was used, as
discussed in section E.2.2.2.
The necessary illustrations are discussed below:
o Figure E-8: Existing levels and future noise levels without the
proposed project; 1985
The noise levels in 1985 without the project are
the same as the noise levels in the existing
situation. This lack of change is by assumption in
this example.
o Figure E-10: Future noise levels of the pr ject alone; 1985
o Figure E-l1: Future levels from all noise sources combined; 1985
The data contained in Figures E-8 and E-10 are
combined to create contours of total noise
exposure.
o Figure E-l2: Future levels without the proposed project; 2Q01
This represents the noise intrinsic to tne neigh-
borhood which is expanded, the highway, and levels
of noise from the increased usage of the existing
single runway.
**Logarithmic combinations are discussed at the end of this appendix.
E-28
-------
o Figure £-9: Future noise levels of the project alone; 2001
o Figure E-13: Future levels from all noise sources combined; 2001
The data contained in Figures E-9 and E-12 are
combined to create contours of total noise
6XpO SUIT 6 *
1.2.4.2 Determining the base area and base population. As noted in section
2.1.3, the base population is defined as the number of people living in areas
with outdoor levels of noise produced by the project alone above a specified
L^jj value. This is called the base L^q. The base L^n is determined by
reference to the existing yearly L^n contours in the residential area
(Figure E-8). From Figure E-8, the lowest L
-------
INCLUDES:
• NOISE LEVELS FROM BOTH ORIGINAL AND PROJECT RUNWAYS
CORRESPONDS TO TABLE E-7 ~
1hffl
lllllltlliv
70
* # • » * • m • • **¦'
Fisun E-10. Sample Datt Pnwintttion for Airport ixampli: Futur* Noisa Lsvob of th« Projact Alan*;
E-30
-------
INCLUDES.
•	NOISE FROM THE HIGHWAY
•	SELF-GENERATED NOISE FROM
BOIHNEIGraORHOOOS
•	NOISE fflCM BOTH THE ORIGINAL
AND WE PROJECT RUNWAYS
CORRESPONDS TO TASLE E-8
iwmmmrnmmmmmm
¦¦••¦•••"•J1
-mmrnmm******

65
.. s
Figuit E-11. Sampi# Data Presentation for tfm Airpcrt fxampta: Future Levuli from All Noiie Saurctt Combined: 198S
E-31
-------
INCLUDES:
•	NOISE FROM THE HIGHWAY
•	SELF-GENERATED NOISE FROM BOTH
eyBikurcn
EXrWlDNeiiittmMfi
•	NOSS R*JM TOE CCMMEBCtAL
IPCXJ5TR! AL ZONE
•	NOISE FROM THEORICIKM. RUNWAY
CORRESPONDS TO TABLE E-9
lion
60
tlxaiMfivfl****'"*"* -
lilmiiZmZiZlmmummmwmmm*
mm m # ** «#«••#» •»•#*« *2f*i5 If
60
75
\
Fijun* i-12. Swnpl* Data Prwmtation for th« Airport Example: Future Noisa Levels without the Proposed Project: 2001
E-32
-------
65
INCLUDES:
•	NOISE FROM THE HIGHWAY
•	SELF-GENERATED NOtSE FROM BOTH
EXPAMDeJMElGHBORHOOCS
•	NOISE FBGM BOTH THE ORIGINAL
and the pwwect runways
CORRESPONDS TO TABLE E-10
\
ssr=Ki;ss21i=|ilillII£
65
70
Figure E-13. Sunpie Data Presentation for the Airport Example: Future levels of Noise
from Alt Noiie Sourcet Combined; 2001
11on
E-33
-------
E.2.4.3 Transferring the data to the tables. Tabulations of population and
the area exposed are provided in Tables E-5, -6, -7, -8, -9, and -10, corre-
sponding respectively to Figures E-8, -9, -10, -11, -12, and -13. The values
in the tables are derived by summing the number of people and the area of land
within each five decibel band, for exaaple, in Figure E-13:
E.2.4.4 Calculating the single number indices. For this comparison, five
single number indices should be considered; (1) the sound level-weighted
population (LWP); (2) the noise impact index (Nil); (3) the relative change
of impact (&G1); (4) hearing loss-weighted population (HWF); and (5) the
average potential hearing loss (PHL). The first three indices (explained
in section 2.2.2.b) concern the range of general adverse noise effects; the
latter two (explained in section 2.3.2) concerns noise levels which possibly
nay cause severe health effects. The indices LWP, Nil, HWP and PHL should
be computed for each of the tables.
Noise Level (Ldn(yP
Residential
Population
80+
1,233
30,799
30,346
3,942
1,971
75-80
70-75
65-70
60-65
55-60
50-55
0
0
S-34
-------
TABLE E-5
SAMPLE DATA PRESENTATION FOR AIRPORT EXAMPLE:
FUTURE LEVELS WITHOUT PROPOSED PROJECT; 1985
Yearly Ldn
(dB)
Residential
Populat ion
Industrial/
Commerc ial
Employees
Total Land
Area (sq. km.)
Residential Land
Area (sq. km.)
Industrial/
Commercial Land
Area (sq. km.)
80-85
0
0
0
0
0
75-80
0
0
0
0
0
70-75
0
1,550
8
0
8.0
65-70
27,061*
7,264
42
3.14
38.86
60-65
4,628
10,822
19.2
4.48
14.72
55-60
0
6,814
135.8
0
135.8
<55
0
41,678
95.0
0
95.0
31,689	68,128	300.0	7.62	292.38
Level Weighted Population (LWP) = 5,787
Noise Impact Index (Nil) = 0.183
Hearing Loss-Weighted Population (HWP) = 0
Average Potential Hearing Loss (PHL) = 0
Corresponds to Figure E-8
Includes: o Highway noise
o Self-generated noise from both neighborhoods
o Noise from the original runway
Note: Single number indices are not computed on the
basis of industrial/commercial employees.
Large number of people in the 65-70 dB band
is attributable to high ambient noise levels
(non-aircraft related) in the high density
residential area (See section E.2.2.2).
-------
TABLE E-6
SAMPLE DATA PRESENTATION FOR AIRPORT EXAMPLE:
FUTURE NOISE LEVELS OF PROJECT ALONE; 2001
Industrial/	Industrial/
Yearly L,jn	Residential Commercial	Total Land	Residential Land Commercial Land
(dB)	Population	Employees Area (sq. km.)	Area (sq. km.) Area (sq. km.)
80-85
1,233
303
12.0
0.16
11.84
75-80
30,799
19,473
20.7
4
16.7
70-75
30,346
22,921
49.15
4.85
44.3
65-70
2,673
25,431
206.03
1.32
204.71
60-65
3,240
0
12.12
12.12
22.97
55-60
0
0
0
0
0
<55
0
0
0
0
0
68,291	68,128	300.0	22.45	277.55
Level Weighted Population (LWP) = 24,498
Noise Impact Index (NII)= 0.359
Hearing Loss-Weighted Population (HWP) = 408
Average Potential Hearing Loss (PHL) = 0.09
Corresponds to Figure E-9
Includes: o Noise from both the original and the
additional runways.
-------
TABLE E-7
SAMPLE DATA PRESENTATION FOR AIRPORT EXAMPLE:
FUTURE NOISE LEVELS OF PROJECT ALONE; 1985
Yearly Ldn
(dB)
Residential
Populat ion
Industrial/
Commercial
Employees
Total Land
Area (sq. km.)
Residential Land
Area (sq. km.)
Industrial/
Commercial Land
Area (sq. km.)
80-85
0
0
0
0
0
75-80
0
0
0
0
0
70-75
0
5,934
25.6
0
25.6
65-70
5,358
18,708
82.76
2.12
80.64
60-65
26,331
11,349
74.0
5.50
68.5
55-60
0
22,132
92.64
0
92.64
<55
0
10,005
25.0
0
25.00
31,689	68,128	300.0	7.62	292.38
Level Weighted Population (LWP) = 4,094
Noise Impact Index (NII)= 0.129
Hearing Loss-Weighted Population (HWP) = 0
Average Potential Hearing L099 (PHL) = 0
Corresponds to Figure E-10
Includes: o Noise from both the original and the
additional runways.
-------
TABLE E-8
SAMPLE DATA PRESENTATION FOR AIRPORT EXAMPLE:
FUTURE LEVELS FROM ALL NOISE SOURCES COMBINED; 1985
Industrial/	Industrial/
Yearly L
-------
TABLE E-9
SAMPLE DATA PRESENTATION FOR AIRPORT EXAMPLE:
FUTURE LEVELS WITHOUT PROPOSED PROJECT; 2001
Yearly Ldn
(dB)
Residential
Population
Industrial/
Commercial
Employees
Total Land
Area (sq. km.)
Residential Land
Area (sq. km.)
Industrial/
Commercial Land
Area (sq. km.)
80-85
0
0
0
0
0
75-80
0
2,434
8.15
0
8.15
70-75
0
602
20.0
0
20.0
65-70
61,681
6,511
31.85
13.41
18.44
60-65
4,968
23,492
84.0
8.38
75.62
55-60
1,642
16,716
56.0
.66
55.34
<55
0
18,373
100.0
0
100.0
68,291	68,128	300.0	22.45	277.55
Level Weighted Population (LWP) B 12,647
Noise Impact Index B 0.185
Hearing Loss-Weighted Population (HWP) "0
Average Potential Hearing Loss (PHL) ¦ 0
Corresponds to Figure E-12
Includes: o Highway noise
o Self-generated noise from both expanded
neighborhoods
o Noise from the original runway
Note: Single number indices are not computed on the
basis of industrial/commercial employees.
-------
TABLE E-10
SAMPLE DATA PRESENTATION FOR AIRPORT EXAMPLE:
FUTURE LEVELS FROM ALL NOISE SOURCES COMBINED; 2001
Industrial/	Industrial/
Yearly Ljn	Residential Commercial	Total Land	Residential Land Commercial Land
(dB)	Population	Employees Area (sq. km.)	Area (sq. km.) Area (sq. km.)
80-85
1,233
303
12.0
0.16
11.84
75-80
30,799
19,473
20.7
4
16.7
70-75
30,346
22,921
49.15
4.85
44.3
65-70
3,942
25,431
184.3
2.56
181.74
60-65
1,971
0
33.85
10.88
22.97
55-60
0
0
0
0
0
55
0
0
0
0
0
68,291	68,128	300.0	22.45	277.55
Level Weighted Population (LWP) = 24,597
Noise Impact Index (NII)= 0.360
Hearing Loss-Weighted Population (HWP) = 408
Average Potential Hearing Loss (PHL) = 0.09
Corresponds to Figure E-13
Includes: o Highway noise
o Self-generated noise from both expanded
neighborhoods
o Noise from both the original and the project
runways
Note: Single number indices are not computed on the
basis of industrial/commercial employees.
-------
A summary of the assessment results is presented below. Calculation
of the level weighted population was based on the weighting function of
equation 2b, shown in Table 3 of the main text.
From Data In Exanple
	Year	LWP	Table Number
Present (no project)	5,787	1-5
1985 without the project	5,787	1-5
1985 with the project	5,964	E-8
2001 without the project	12,647	E-9
2001 with the project	24,597	E-10
The Noise Impact Index, according to equation 7 in section 2.2.2,2, is
simply the LWP divided by the total population.
From Data In Example
Year	pTotal LWP	Nil	Table Number
Present (no project)	31,689	5,787	0.183	1-5
1985 without the project	31,689	5,787	0.183	E-5
1985 with the project	31,689	5,964	0.188	E-8
2001 without he project	68,291	12,647	0.185	E-9
2001 with the project	68,291	24,597	0.360	E-10
The Relative Change in Impact is calculated from equation 8.
From Data on	From Data in
Airport	Example
Year LWPa Table Number LWP^ Table Number	ECI
1985 5,64	E-6	5,787	E-5	0.0306
2001 24,597	E-8	12,647	E-7	0.9449
As previously noted, the indices representing potential hearing damage
risk are not similar to the other three indices. In order to emphasize the
severity of the health problems caused by high noise levels, a separate
E-41
-------
severe health effects single number index is used. As discussed in Section
2.3.1, far areas with an Ljq of 75 dB* or above, the following information
should be estimated if possible: the population spending time out-of-doors;
the length of time they are out-of-doors; the actual noise levels while
they are out-of-doors. For this exaaple, only the populations within the
residential areas are being considered. Those people in other impacted areas
of the metropolitan area are assumed to remain indoors (because the metro-
politan area is entirely commercial/industrial, so they are not subjected to
the noise.
The area for study of possible severe noise impact shown on Figure E-13
is expanded and shown as Figure 1-14.
The additional information required is now assumed to have been collected
through additional estimates or survey work. It is listed on the next page as
Table E-ll.
The next step is to obtain the at-ear outdoor Leq values of the expo-
sure instead of the Ldn values. The best way is to take additional noise
measurements. A much less preferable way, as explained in Section 3.2.1,
is to use the approximation:
*"eq " ^dn(daytime) ~ ^
This approximation may be used if the difference between Che daytime and
nighttime levels is the typical one where the nighttime level is approxi-
mately 4 dB lower. It has been assumed in this example that sufficient
measurements were taken to determine that the day-night difference in Leq
of that area is a typical one. Thus, the 3 di correction term has been
applied and the results entered in Table E—11.
*As pointed out in Section 2.3.1, the	should be used only to identify
potential problem areas.
1-42
-------
Himnmuumimuiiiifmiiiu
INCLUDES:
•	NOISE FROM THE PBCTOSED PROJECT
•	SELF-GENERATED NOISE FROM THE
HIGH POPULATION DENSITY
NEIGHBORHOOD
CORRESPOMX TO TABLE E-tt
/
Fifure £-14, Sam pi* Dm Pr»*nt»tion for ttw Airport Example: S*vw* Hailtli Anaiysh Anw
E-43
-------
Table E-ll
Sample Data Presentation for Example the Airport: Information required to calculate the PHL
Residential Population
^	 [Exposures in Leq (8)]
Contour
(kdn)
Residential
Population
Median
Contour
(kdn)
Time Outdoors
Estimated
**eq
4 hr
6 hr
8 hr
12 hr
75-77
12,574
76
7,521
^^[70]
1,259
>^172]
2,794
73]
1,000
73
77-79
9,474
78
6,378
72]
1,583
[74]
819
./[75]
694
y/vn\
75
79-81
8,953
80
5,899
[74]
2,542
[76]
287
Vll\
225
77
81-83
1,031
82
691
[76]
176
781
97
^/[79]
67
79
TOTAL
32,032

20,489
5,560
3,997
1,986

* Calculated as explained in Section
Corresponds to Figure E-14
-------
Next, since not all residents are exposed to exactly eight hours of out-
door noise, the data in Table E-l 1 are adjusted to the appropriate Leq{g)
values, using Table 1-12. For example, the population of 7,521 exposed to
4 hours of Le_ 0, and Pfotal *s the popula-
tion for the severe health effects area, i.e., the sum of all people exposed
to an Leq(g) greater than 75 dB. Using the information in Table E-ll, the
PHL is:
, - [[P(81)xW(81)] + [P(80)xW(80)] + IP(79)xW(79)l + [P(78)xW(78)M(P(77)xW(77)]+[P(76)xW(76)]]
4779
E-45
-------
TABLE E-12
CONVERSION OF Leq(x) TO Leq(8) AND Leq(24)
^eq(1)
m
Leq(8) "
9
' Leq<24) "14
Leq<2)
m
**eq(8)
6
* ^eq(24) *
**eq(3)
>
^eq(8) ~
4
" ^eq(24) ~ ®
**eq(4)
-
Leq(8)
3
" Leq(24) " 8
Leq(5)
ai
^eq(8)
2
* ^eq(24) ~ ^
Leq(6)
»
Leq(8) "
i
" Leq(24) " 5


*"eq(8)

" ^eq(24) ~ ^
Leq(10)
-
Leq(8) +
l
* Leq(24) - 4
Leq(12)
-
Leq(8) +
2
* Leq(24) " 3
Leq(16)
-
Leq(8) +
3
* **eq(24) ~ ^
E-46
-------
' " [ [(67)x(0.9)] + [(O)x(0.625)] + [(322)x(0.4)J + [( 176)x(0.225)]+[(981)x(0.1) 1 (3233)x(O.Q25) 3 ]
Tm
PHL - 408 » 0.09
4779
E.2.5 Conclusions of the noise analysis
The purpose of the noise analysis is to compare the number of people
affected by the noise levels with and without the project. To do this
comparison, the single number indices are used. In tabular form, they are
shown in Table E-13, These indices show: 177 more people in the residential
areas will be fully adversely affected by the noise created by the project
in 1985 (when compared with the existing situation or with 1985 without the
project); 18,810 more people in the residential areas will be fully adversely
affe.cted by the noise from the project in 2001 (when compared with the exist-
ing situation); 11,950 more people will be fully adversely affected by the
noise created by the project in 2001 (when compared with 2001 without the
project). In addition, the PHL for the year 2001 increases from 0 to 0.09.
Footnote to the highway and airport examples:
Step-by-step explanation of combination of noise contours from different
sources.
How are the noise levels on Figures E-2 and £-4 combined?
Using Table E-14, combine the noise levels shown on Figures 2 and 4 by deter-
mining the difference between levels at the same point, and adding the appro-
priate amount from the table to the higher level.
E-47
-------
TABLE E-13
SUMMARY OF AIRPORT EXAMPLE
Single
Number
Index
Without the Project
With the Project
Difference
Between the
Existing &
1985 with
the Project
Difference
Between the
Existing &
2001 with
the Project
Difference
Between 1985
without the
Project and
1985 with
the Project
Difference
Between 2001
without the
Project and
2001 with
the Proiect
Existing
and 1985 2001
1985 2001
LWP
(people)
5,787 12,647
5,964 24,597
177
18,810
177 11,950
Nil
0.183 0.185
0.188 0.360
0.005
0.177
0.005
0.175
RCI
-
-
For 1985: 0.0306 For 2001: 0.9449
PHL
0 0
0 0.09
0
0.09
0
0.09
-------
TABLE E-14
Difference becween
Levels in decibels
Number of decibels
Co be added Co
Higher Level
0
1
2
3
4
5
6
7
8
9
10
12
14
16
3.0
2.6
2.1
1.8
1.5
1.2
1.0
0.8
0.6
0.5
0.4
0.3
0.2
0.1
For example, Che noise level at Che firsC row of houses is 60 dB in
Figure E-2 and 65 dB in Figure E-4, a difference of 5 decibels. Table
E-14 shows Chat for a difference of 5 dB, approximately 1 dB should be
added Co the higher level in order Co derive the cotal level. Therefore,
Che noise level at Che fir3C row of duplexes in Figure E-5 i3 computed as
66 dB. Similarly, the noise level contour at the second row of houses is
64 dB. Table E-15 shows these calculations.
E-49
-------
lex
1
2
3
4
5
6
7
8
9
10
11
TABLE E-15
Add to
Higher
Figure E-2 Figure S-4 Difference Level	figure £-5
60
65
5
1.2
or
1
66
58
62
4
1.5
or
2
64
56
58
2
2.1
or
2
60
55
54
1
2.6
or
3
58
54
53
1
2.6
or
3
57
53
51
2
2.1
or
2
55
53
49
4
1.5
or
2
55
53
48
5
1.2
or
1
54
52
48
4
1.5
or
2
54
52
47
5
1.2
or
1
53
51
47
4
1.5
or
2
53
1-50
-------
PARTIAL BIBLIOGRAPHY OF MODELS
FOE PREDICTING NOISE LEVELS FROM VARIOUS SOURCES
Highway Noise
U.S. Environmental Protection Agency, Office of Noise Abatement
and Control. Comparison of Highway Noise Prediction Models.
EPA 550/9-77-355. May, 1977.
U.S. Environmental Protection Agency, Office of Noise Abatement
and Control. Highway Noise Impact. EPA 550/9-77-3 56,
May, 1977.
U.S. Department of Transportation, Transportation Systems Center.
User's Manual For the Prediction Of Road Traffic Noise
Computer Programs. DOT-TSC-315-1. May, 1972.
National Academy of Sciences, Highway Research Board. Highway
Noise - a Design Guide For Engineers. Report 117. 1971.
National Academy of Sciences, Highway Research Board. Highway
Noise - A Field Evaluation of Traffic Noise Reduction Mea-
sures. Report 144. 1973.
U.S. Department of Transportation, Federal Highway Administration.
A Revised Program and User's Manual for the FHWA Level I
Highway Traffic Noise Prediction Computer Program. FHWA-DP-
45.4. December, 1980.
U.S. Department of Transportation, Federal Highway Administration.
User's Manual: FHWA Level II Highway Traffic Noise Predic-
tion Model. FHWA-RD-78-138. May, 1979.
Aircraft Noise
U.S. Environmental Protection Agency, Office of Noise Abatement
and Control. Calculation of Day-Night Levels (L^n) Resulting
From Civil Aircratt Operations"! EPS	/-45U. January,
1977.
U.S. Department of Transportation, Federal Aviation Administra-
tion, Office of Environmental Quality. Federal Aviation
Administration Integrated Noise Model. April, 1978.
U.S. Department of Transportation, Federal Aviation Administra-
tion, Office of Environmental Quality. Federal Aviation
Administration Integrated Noise Model Version I.
FAA-EQ—78-01. January, 1978.
E-51
-------
U.S. Department of Defense, Air Force Aerospace Medical Research
Laboratory. Community Noise Exposure Resulting From Aircraft
Operations: Computer Program Description, AMRL-TR-73-109,
November, 1974. Computer Program Operator's Manual, AMRL-TR-
108, July, 1974. N0IS1 HAP 3.4 Computer Program Operator's
Manual, AMRL-78-109, December, 1978.
Rapid Transit Noise
U.S. Department of Transportation, Urban Mass Transportation
Administration, Office of Technology Development and Deploy-
ment, Office of Rail and Construction Technology, Noise
Rating Criteria for Elevated Rapid Transit Structures.
Report No. UMTA-MA-06-0099-79-3. May, 1979.
Transmission Line Moise
Comber, M.G., and L.E. Zaffanella. "Audible Noise." In: Trans-
mission Line Reference Book 345 KV and above. Published by
Electric Power Research Institute, 3412 Hillview Avenue,
Palo Alto, CA 94304, 1975.
Driscoll, D.A., and F.G. Eaag. "Prevention and Control of Envi-
ronmental Noise Pollution in New York State." In: Proceed-
ings of a Workshop on Power Line Noise as Related to Psycho-
acoustics . Published by the Institute of Electrical and
Electronics Engineers, Inc., 345 East 47th St., New York, NY
10017, 1976.
Molino, J,A., G,A. Zerdy, N.D. Lerner, and D.L. Sarwood. "Psycho-
acoustic Evaluation of the Audible Noise From EHV Power
Lines." National Bureau of Standards. To be published.
Kolcio, N., J. DiPlacido, and F.M. Dietrich. "Apple Grove 750 KV
Project - Two-Year Statistical Analysis of Audible Noise
from Conductors at 755 KV and Ambient Noise Data." In: IEEE
Transactions on Power Apparatus and Systems, 1977.
Outdoor Recreational Noise
Harrison, R.T., R.N, Clark, and G.H. Stankey; "Predicting Impact
of Noise on Recreationists. U.S. Department of Agriculture,
Equipment Development Center. ED&T Project No. 2688. April,
1980.
High-Energy Impulsive Noise
Siskind, D.I., V.J. Stachura, M.S. Stagy, and J.W. Kopp, "Struc-
ture Response and Damage Produced by Airblast From Surface
Mining." U.S. Department of the Interior, Bureau of Mines.
Report of Investigation 8485. 1980,
E-52
-------
Schotner, P.D., L.L. Little, D.L. Effland, V.I, Pawlowska, and
S.G. Roubik, "Blast Noise Prediction Volume I; Data Bases
and Computational Procedures." U.S. Army Construction
Engineering Research Laboratory. Technical Report N-98,
March, 1981.
Reed, J.W., "Atmospheric Attenuation of Explosive Haves," The
Journal of the Acoustical Society of America, 61 (1). pp.
39-47, 1977.
Maglieri, D.J., H.W. Carlson and H.H. Hubbard, "Status of Know-
ledge of Sonic Booms." Noise Control Engineering, 15 (2).
pp. 57-64, 1980.
E-53
-------