NTID300.2
NOISE FROM INDUSTRIAL PLANTS
DECEMBER 31, 1971
U.S. Environmental Protection Agency
Washington, D.C. 20460
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NOISE FROM INDUSTRIAL PLANTS
DECEMBER 31, 1971
Prepared by
L. S. GOODFRIEND ASSOCIATES
under
CONTRACT 68-04-0044
for the
U.S. Environmental Protection Agency
Office of Noise Abatement and Control
Washington, D.C. 20460
This report has been approved for general availability, The contents of this
report reflect the views of- the contractor, who is responsible for the facts
and the accuracy of the data presented herein, and do not necessarily
reflect the official views or policy of EPA. This report does not constitute
a standard, specification, or regulation.
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TABLE OF CONTENTS
Page Number
FOREWORD ix
1. SUMMARY I
2. INTRODUCTION 13
2.1 Background 13
2.2 Site Selection 18
2.3 Noise Surveys 21
2.3.1 In-Plant Noise Sources 21
2.3.2 Community Noise Sources 22
2.3.3 Data Acquisition 22
2.3.4 Data Reduction 24
2.3.5, Data Analysis 25
2.4 Examination of Noise Effects 28
2.5 Noise Abatement Technology Assessment 30
3. FIELD SURVEY RESULTS 32
3.1 Glass Manufacturing Plant 33
3.1.1 Plant Noise Sources 33
3.1.2 Source Noise Levels 34
3.1.3 Community Noise Levels 35
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Page Number
3.2 Oil Refinery 37
3.2.1 Refinery Noise Sources 38
3.2.2 Source Noise Levels .38
3.2.3 Community Noise Levels 40
3.3 Power Plant 42
3.3.1 Plant Noise Sources 42
3.3.2 Source Noise Levels 43
3.3.3 Community Noise Levels 44
3.4 Automobile Assembly Plant 46
3.4.1 Plant Noise Sources 46
3.4.2 Source Noise Levels 47
3.4.3 Community Noise Levels 48
3.5 Can Manufacturing Plant 50
3.5.1 ^±ant Noise Sources 51
3.5.2 Source Noise Levels 51
3.5.3 Community Noise Levels' 52
4. IMPACT OF INDUSTRIAL PLANT NOISE SOURCES 202
4.1 On the Work Environment 202
4.2 On the Community Environment 205
4.2.1 Magnitude of the Impact 205
4.2.2 Behavioral Response 206
4.2.3 Plant-Community Accommodations 208
4.2.4 Community Noise Equivalent Level 214
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Page Number
5. ATTITUDES TOWARDS NOISE LEGISLATION 223
5.1 Of the Industrial Plants 223
5.2 Of the Community 225
6. NOISE REDUCTION PROGRAMS FOR INDUSTRIAL 228
PLANTS
6.1 Introduction 228
6.2 Motivation 229
6.3 Methods of Approach 231
6.4 Future Committoeat 233
6.5 Plant Programs (Bast, Present, and 234
Future)
7. NOISE ABATEMENT TECHNOLOGICAL ASSESSMENT 244
7.1 At the Equipment Manufacturers Level 244
7.2 State-of-the-Art Noise Abatement 262
Technology
7.2.1 Introduction 262
7.2.2 Source Noise Control 265
7.2.3 Transmission Path Noise Control 268
7.2.4 Machinery Equipment and Process 273
Noise Control
APPENDIX A - REFERENCES A-l
APPENDIX B - SELECTED BIBLIOGRAPHY B-l
APPENDIX C - STANDARDS and SPECIFICATIONS C-l
APPENDIX D - INSTRUMENTATION, FLOW DIAGRAMS D-l
and SAMPLE COMPUTER PRINTOUTS
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LIST OF FIGURES
Figure Number
1-1 - 1-5 Community Ambient Noise Levels for Representative
Communities
2.3.3-1 Block Diagram of Recording Instrumentation System
3.1.2-1 - One-Third Octave Band Sound Pressure Levels of
3.1.2-4 Noise Sources in Glass Manufacturing Plant
3.1.3-1 Glass Manufacturing Plant Community Noise Levels
3.1.3-2 - Glass Manufacturing Plant Community Statistical
3.1.3-14 Noise Spectra
3.1.3-15 - Glass Manufacturing Plant Community Noise Level
3.1.3-27 Histograms
»
3.2.2-1 - One-Third Octave Band Sound Pressure Levels of
3.2.3-8 Noise Sources in Oil Refinery
3.2.3-1 Oil Refinery Community Noise Levels
3.2.3.2 - Oil Refinery Community Statistical Noise Spectra
3.2.3-9
3.2.3-10 - Oil Refinery Community Noise Level Histograms
3.2.3-18
3.3.2-1 - One-Third Octave Band Sound Pressure Levels of
3. 3."2-4 Noise Sources in Power Plant
3.3.3-1 Power Plant Community Noise Levels
3.3.3-2 - Power Plant Community Statistical Noise Spectra
3.3.3-9
3.3.3-10 - Power Plant Community Noise Level Histograms
3.3.3-17
i.4.2-1 -
i.4.2-12
One-Third Octave Band Sound Pressure Levels of
Noise Sources in Automobile Assembly Plant
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Figure Number
3.4.3-1 Automobile Assembly Plant Community Noise Levels
3.4.3-2 - Automobile Assembly Plant Community Statistical
3.4.3-10 Noise Spectra
3.4.3-11 - Automobile Assembly Plant Community Noise Level
3.4.3-19 Histograms
3.5.2-1 - Octave Band Sound Pressure Levels of Noise Sources
3.5.2-11 in Can Manufacturing Plant
3.5.3-1 Can Manufacturing Plant Community Noise Levels
3.5.3-2 - Can Manufacturing Plant Community Statistical
3.5.3-11 Noise Spectra
3.5.3-12 - Can Manufacturing Plant Communiyt Noise Level
3.5.3-21 Histograms
4.2.4-1 Correlation of NCNEL with Community Response
7.2.4-1 Noise Quality Classification for Geared Systems
D-la - D-ld Plow Charts - Statistical Data Analysis
D-2 Sample Statistical Analysis Computer Printout
D-3 Sample Noise Level (A-Weighted) Histogram Printout
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LIST OF TABLES
Table Number
1-1 Range of Industrial Machinery, Equipment, and Process
Noise Levels
2.2-1 Types of Industrial Plants Selected
3.1.3-1 Glass Manufacturing Plant Community Intrusive Noise Levels
3.2.3-1 Oil Refinery Community Intrusive Noise Levels
3.3.3-1 Power Plant Community Intrusive Noise Levels
3.4.3-1 Automobile Assembly Plant Community Intrusive Noise Levels
3.5.3-1 Can Manufacturing Plant Community Intrusive Noise Levels
4.2.4-1 Community Noise Equivalent Levels (CNEL)
4.2.4-2 CNEL Corcections
4.2.4-3 Adjustments and NCNEL
6*2-1 Representative Noise Regulations
3.2.2-1 Basic Techniques for Machinery Noise Control
7.2.3-1 Noise Reduction Methods
7.2.4-1 Representative Pneumatic Tool Noise Levels
7.2.4-2 Gear Noise Classification
7.2.4-3 Available Noise Reduction for Geared Systems
7.2.4-4 Sources of Noise and Methods 6f Noise Reduction for
Process Plant Equipment
D-l Instrumetifeation List
D-2 Attenuation Courections
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FOREWORD
The objectives of this study included the following:
(1) To identify as many sources of noise as possible
in five typical industrial plants. The plants
selected for the field survey included the follow-
ing types:
(a) Glass Manufacturing Plant
(b) Oil Refinery
(c) Power Plant
(d) Automobile Assembly Plant
(e) Can Manufacturing Plant
(2) To measure the in-plant source noise levels.
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(3) To measure environmental noise in the communities
adjacent to the above industrial plants.
(4) To determine the community noise exposure and impact
due to industrial plant noise.
(5) To identify the human-related problems associated
with the noise sources.
(6) To identify the contributory reasons for initiating
noise abatement programs and current attitudes
toward noise legislation.
(7) To identify the groups or organizations responsible
for initiation of the noise abatement programs.
(8) To assess the state-of-the-art for application of
noise abatement technology to the noise sources
identified above.
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1. SUMMARY
Industrial plant activity in the United States ranges
from the very small - one man garage operation - to.
the very large - multimillion dollar, multiproduct operation.
The U.S. Bureau of the Census in Statistical Abstract of
the United States (1971) reports that the total number of
industrial establishments for the year 1971 was 311,000
and the plants employ approximately 14,356,000 production
workers.
The types of industrial plants vary greatly in scope,
but have been categorized for this study into'four basic
types:
(1) Product fabrication plants,
{2} "Assembly plants,
(3) Power generating stations, and
(4) Process plants.
The product fabrication plant category, due to the broad
range of activities, was further subdivided into metal
fabricating plants and molding plants.
A representative industrial plant was selected from each
category for this study. The plants selected and the
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number of each type in the United States are presented
as follows:
No. of Plants
Category Survey Plant in U.S.
Molding Glass Manufacturing 305
Process Oil Refinery 438
Power Power Plant 3429
Assembly Automobile Assembly Plant 98
Metal Fabrication Can Manufacturing 300
Note that the number of plants in the country represented
by the plants surveyed consists of only 1.5 percent of the
total of 311,000 industrial plants in the United States.
This is considered a small sample.
Industrial plants, though clustered near large urban centers
needed for manpower pools, may also be found located in
suburban and rural communities. Site selection parameters
for new facilities are complex and beyond the scope of this
report. Noise is a parameter oftentimes considered. An
excellent example is a typical public utility power plant
where a total pollution impact study (including noise) is
prepared prior to final site selection. The power plant
corporate management, sensitive to community response,
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authorize noise surveys prior to plant construction and
insure, through noise abatement controls, that community
ambients are not markedly increased when the plant is in
full operation.
Typical industrial plants (glass manufacturing, oil refinery,
power generating, automobile assembly, and can manufacturing)
located in urban, suburban, and rural communities were
surveyed. The noise at communities adjacent to these
industrial plants was recorded for five minute sampling
periods during two days and nights when the plants were
operating normally. During appropriate weekend periods,
noise levels (A-weighted) were observed at the plant boundary
and in the communities at the locations chosen for the
.recordings. The ambient noise level, I*gn' is defined as
the level of noise exceeded 90 percent of the time during
the sampling period, while the intrusive noise level, L-,0/
is that level of noise exceeded only 10 percent of the time
during the sampling period.
The weekday, weeknight, and weekend average ambient noise
levels in the community and at the plant property line are
presented together with maps of each area as Figures 1-1
through 1-5.
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Scale
o 9x> leap &x> toga i»o
Feet
Weekend
Weekday
Weeknlght
Weekend
Weekday
Weeknight
Community Noise Levels in dB(A)
1 2 3 4 5 6 7 8 9 10 11 12 13
46 54 45 39 41 43 - - 48 41 41 51 43
50 59 44 42 42 40 44 40 41 44 39 53 43
52 61 46 40 43 45 43 40 41 41 42 49 42
Plant Property Line Noise Levels in dB(A)
aefjmqccaaxv"
50 62 59 68 55 41 44 40 60 65 52
49 64 61 68 59 49 50 49 66 .68 55
51 64 63 69 58 48 41 46 61 65 54
Industrial Noise Source
Residential Area
Railroad Track
Highway
Measurement Location
Figure 1-1
Glass Manufacturing Plant Community
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Weekend
Weekday
Weeknight
Weekend
.Weekday
Weeknight
Community Noise Levels in dB(A)
1 23456789
59 49 52 55 50 50 50 48 51
63 52 50 56 48 51 54 47 50
60 51 51 50 47 49 59 47 49
Plant Property Line Noise Levels in dB(A)
abcdefghi
55 71 60 60 60 55 54 52 56
63 68 60 62 64 63 51 52 53
58 67 59 59 62 61 49 50 54
500O
Industrial Noise Source
Residential Area
Railroad Track
Highway
Measurement Location
Figure 1-2.
Oil Refinery Community
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Weekend
Weekday
Weeknight
Weekend
Weekday
Weeknight
Community Noise Levels in dB(A;
1 2345678
48 50 50 50 52 58 57 54
48 51 49 53 55 56 55 54
51 52 52 52 53 56 57 54
Plant Property Line Noise Levels in dB(A)
abcdefghi
81 58 63 69 64 53 54 59 68
64 59 61 72 80 61 59 57 63
68 63 67 70 80 61 60 61 65
Industrial Noise Source
Residential Area
Railroad Track
Highway
Measurement Location
Figure 1-3-
Power Plant Community
— 6—
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Feet
Weekend
Weekday
Weeknight
Weekend
Weekday
Weeknight
Key
Community Noise Levels In dB(A)~
1 23456789
47 43 49 45 43 47 45 43 47
50 48 50 49 47 54 50 53 50
51 50 50 50 47 52 48 54 48
Plant Property Line Noise Levels in dB(A)
abcdefghi j
54 47 46 46 47 54 54 49 54 46
58 57 55 53 54 62 57 54 55 54
57 57 56 51 53 58 55 53 54 54
Industrial Noise Source
Plant Property Line
Residential Area
Railroad Track
Highway
Measurement Location
Figure 1-4.
Automobile Assembly Plant Community
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Scale
6 500
Feet
\ooo
I&3O
zooo
Weekend
Weekday
Weeknight
Weekend
Weekday
Weeknighf
Community Noise Levels in dB(A)
123456789 10
55 49 53 51 50 50 57 56 51 58
53 49 55 49 51 54 59 56 56 55
48 49 53 51 47 49 58 50 55 47
Plant Property Line Noise Levels in dB(A)
abcdefghi {
58 59 59 61 58 58 52 50 49 53
60 65 64 65 60 60 56 52 57 63
53 63 63 61 58 62 53 43 53 66
Industrial Noise Source
Residential Area
Railroad Track
Highway
Measurement Location
Figure 1-5. Can Manufacturing Plant Community
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A study of the- community noise data indicates that only
two (automobile assembly plant and glass manufacturing
plant) of the five plants surveyed are the principal source
of community noise. Surface transportation noise due
to superhighways near the oil refinery and power plant,
and bus and truck traffic near the can manufacturing plant
either predominate or contribute equally with the industrial
plant to community noise.
Discussions with township officials, board; of .Health
officials, and plant management indicate that major com-
plaints are being received at the glass manufacturing
plant and sporadic complaints are received from the power
plant community only when a gas turbine generator is used.
Although the automobile assembly plant is the source of
noise in its adjacent community, no complaints have been
generated.
It appears that complaints, or a lack of complaints, may
not be a satisfactory indicator of the impact of plant noise
on its neighbors. Industrial plant neighbors in a community
many not object to plant noise even at fairly high levels
(a) if it is continuous,
(b) If it does not interfere with speech communication,
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(c) if it does not include pure tones or impacts,
(d) if it does not vary rapidly,
(e) if it does not interfere with getting to
sleep, and
(f) if it does not contain fear-producing elements.
Sometimes political, social, or economic situations
develop where noise which is normally objectionable causes
no complaints. Often single individuals or families may
be annoyed by an industrial noise which does not annoy other
plant neighbors. This, in many cases, may be traced to
unusual exposure conditions or to interpersonal situations
involving plant management personnel.
It is anticipated that the noise levels due to industrial
plants will not increase in level or importance relative
to the noise from construction activity, surface transporta-
tion or aircraft. As noise abatement efforts within the
plant motivated by the Occuational Safety and Health Act
of 1970 and local "nuisance" laws and zoning ordinances
are successful, noise levels may in fact be reduced. Often
plant management, in its desire to maintain good community
relations, will initiate noise control programs. The goals
of such programs are to reduce interior noise to below
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levels hazardous to hearing (see Table 1-1) and to reduce
exterior noise to below levels which generate complaints
although complaints may not be a satisfactory indicator
of noise impact.
Industrial plant noise, anticipated at the early phase of
plant development, can be readily controlled. Noise
reduction programs for plants already in operation are
usually directed at reducing noise along its transmission
path. Many corporations are developing noise specifications
for new equipment. When used by their purchasing agents,
these specifications should aid in the noise abatement
effort as obsolete noisy equipment is replaced.
Noise from industrial plants falls below that of construction
activity or surface and air transportation in importance
when considered nationally. As noise abatement efforts
successfully reduce the levels of these other noise sources,
industrial noise will rise in importance. When this occurs,
as-it does in many communities on a local basis, the noise
reduction programs now being instituted or reserved for
future action should prove satisfactory.
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Table l-l - Range of Industrial Machinery, Equipment
and Process Noise Levels Measured at
Operator Positions (except where noted)
1 . Pneumatic Power Tools
(grinders ,_ehippers,
etc,)
2. Mo|ding Machines
(I.S., blow molding,
etc.)
3. Air Blow-Down Devices
(painting, cleaning,
etc.)
4. Blowers f farced. Induced,
fan, etc.)
. Air Compressors (recipro-
cating, centrifugal)
6. Metal Forming (punch,
shearing, etc.)
7. Combustion (furnaces,
flare stacks) 20 ft.
8. Turbo-generators
(steam) 6 ft.
9. Pumps (water,
hvdraulic. etc.)
10. Industrial Trucks '
(LP gas)
1 1 . Transformers
Noise Levels - dB(A)
80 85 90 95 100~ 105 T|Q 115 120
— — «
•
•
mmmmmm
-
—
»
— ^-i
^MMMHM
••i
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2. INTRODUCTION
2.1 Background
Of all the pollutants, noise is the only one that does not
leave a residue. To determine how much noise has been
made at any location, it must be measured as it is being
made, or at least recorded precisely for measurement and
analysis at a later time. In contrast, gaseous emissions
and particulates may be collected and examined at a later
time, and water pollution can be measured in terms of either
the emission or the resultant water quality. Since noise
must be measured either as a source emission or as a
remotely detected signal that ceases when the emission ceases,
it has' been difficult to examine the environmental distribu-
tion of transient noise signals mixed with continuous
noise and to study the environmental effects. It is also
difficult to study the adverse effects of noise because
there are no directly observable tangible effects of noise
on people when the levels of noise are below those that will
cause temporary loss of hearing; and these levels are well
above those that cause interference with speech communica-
tion and distraction from creative tasks.. It is, however,
the continued small interference with the daily life of
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individuals that appears to cause annoyance or to convey
unpleasant information. These annoyance and'information
effects combined with distraction appear to be capable
of generating strong and generalized psychophysical stress,
negative emotional responses/, of preventing self-renewal,
of causing some direct psychophysical responses. These
include changes in skin temperature, blood pressure, pulse
rate, and other indicators of autonomic changes in adreno-
cortical systems. In other words, the whole psychophysio-
logical system of the body may respond to noise without
any knowledge of this response on the part of the individual
exhibiting the response. The result may be solely physical
or through the complex psychophysiological response chain
may generate strong, or even violent, behavioral reactions
on the part of the auditor. The system is so complex within
the context of the entire socio-political area that today
entire municipalities are deeply committed to noise abatement
programs. The levels of noise are quite disparate and
confirm the premise that it is not necessarily the level, but
the information content of the noise that is significant.
It may be assumed that more is known about the noise environ-
ment of man than about man's response to noise. This is not
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the case. Although considerable work has been done in
an effort to delineate the exposure of various groups or
political subdivisions to noise/ to date no system has
been developed which simply and suitably describes a noise
environment. Even a complex description of environmental
noise may be inadequate for predicting human response.
Noise is a multidimensional phenomenon and its basic physical
attributes do not adequately describe it in terms that
permit simulation for laboratory studies, or for rank order-
ing or comparison if the noises are from sources that are
not almost identical. Among the problems of describing any
given noise environment are the lack of descriptors, much
less scales, for sound "quality." Current technology makes
use of only the simplest descriptors, the physical para-
meters: frequency, level, and time (duration) usually.
However, it is well known that human response at levels
below those causing speech interference is sensitive to
the number and phase relationship of pure tones, whether
alone or buried in random-type noises. The on-off behavior
of some noises such as the cycling of air-conditioning
dequipment has a strong influence on human acceptability of
noise, but most work to date looks only at the total "on" time,
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Furthermore, the information content of the noise may
vary widely. The un-air-conditioned neighbor may be
reminded of the social status associated with the fully
air-conditioned home whenever he hears his neighbor's
machine cycling at a typical eight- to twelve-minute rate.
Industrial noise may be a reminder to some individuals
of the social and economic status that they believe they
might enjoy if the industry were not there. Aircraft noise,
sirens, and explosive sounds often carry fear stimuli for
urban and suburban dwellers.
It is within this context that the following goals of this
program were formulated:
(1) Measure and appropriately describe sources of
noise in industry that contribute to environmental
noise.
(2) Measure the resultant noise in the community in
general.
(3) Examine the various effects of the environmental
noises measured or located on the people exposed,
and identify or relate in some way the various
human response phenomena associated with audition
of the noise sources in the community. This would
include as many of the various psychophysiological
effects as can be related within the present
state-of-the-art, as well as an estimate of other
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effects that are only now being limned by current
exploratory research.
(4) Examine the currect situation with respect to noise
abatement and develop a picture of the current
level of activity and the reasons for the activity
in various industries (other than current federal
statutes related to hearing conservation), and
identify the activity that initiated noise abate-
ment action.
(5) Develop a picture of the present state-of-the-art
in noise abatement in industry, including the
environmental control efforts, using non-source-
related techniques such as barriers, enclosures,
and site planning, as well as the technology of
source-related equipment and techniques. This
work will include discussions of available tech-
nology not now applied, possible innovative
approaches that might be explored, and the pay-
offs and tradeoffs that are available with more
effective noise abatement, both generally and
specifically.
(6) Explore the planning currently going on for further
means of achieving noise reduction both by abatement
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procedures and hardware and by means of process
redesign and new production technology, and Out-
line those areas and items for which noise control
is currently either not considered feasible, or
for which none has been contemplated, along with
the rationale 6f the manufacturers and users that
leads to this situation.
The goals described above were accomplished using state-
of-the-art data acquistion techniques and appropriate
instrumentation, measurement methodology, and analysis
methods. The measured sound levels are related to the
behavioral responses developed either from theoretical con-
siderations, field survey, or empirical relationships
developed by earlier studies. Further, an assessment of
the state-of-the-art with respect to noise abatement methods
and procedures was developed from discussions with manage-
ment, engineering, and industrial hygiene personnel of
industrial plants and equipment manufacturers, and a
thorough search of the current literature.
2.2 Site Selection
This study was initiated with a search for typical industrial
plants with acceptable communities from the following five
categories:
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(a) Rolling Mill
(b) Assembly Line Plant
(c) Oil Refinery
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Table 2.2-1 - Types of Industrial Plant Selected
Typical Industrial Plant
Can Manufacturing Plant
Glass Manufacturing Plant
Automobile Assembly Plant
Electric Power Plant
Oil Refinery
Category
Metal Fabrication
Molding
Assembly Operation
Power Generation
Oil Refinery
Number in United States
300
305
98
3429
438
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2- 3 Noise Surveys
2-3.1 Plant Noise Sources
The basic approach to the plant noise investigation was
based on a detailed inspection of the plant, the objective
being to locate the major noise sources with respect to
both plant and neighboring environments. Measurements were
made as detailed below in order to define the source noise
levels:
(1) A-weighted noise levels and overall noise
levels were observed using a precision sound
level meter,for the purpose of providing data
against which to check tape recorded signals.
(2) Tape recordings of the noise levels at points
located at appropriate far-field or quasi-free
field distances from the source machine or device
under investigation were made using precision
instrumentation-type tape recorders. Acoustic-
calibrator signals were recorded at appropriate
time intervals to determine the absolute signal
levels. Complete system calibrations were performed
on a periodic schedule throughout the measurement
program in order to provide level corrections for
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the one-third octave bands as required.
Measurements were made for appropriate time
periods to insure that the data acquired will
represent the full cycle time of various com-
ponents of the machine or device under test.
2.3.2 Community Noise Sources
Noise levels (A-weighted) at the plants' boundaries were
observed during a weekend or holiday period when the plants
were either secured or in a mode of operation different
from the normal work-week operation. During this weekend
or holiday period, the community residual noise levels
(A-weighted) were also observed at residential locations in
the adjacent communities. Magnetic tape recordings were
obtained at the same residential locations discussed above
during two work days. Data were recorded during daytime,
evening, and nighttime periods. The locations at the plant
property line and in the communities are presented in
Figures 1-1 through 1-5.
2.3.3 Data Acquisition
Noise measurements were accomplished within the industrial
plants and in the community adjacent to these plants using
precision sound level meters and magnetic tape recording
equipment which meets or exceeds all pertinent United States
regulations or standards.
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BRUEL fKJAER TYPE 4^^O
BfK TYPE UAOOS5 ffAHDOM
/A/C/DEMCE CORRECTOR
TYPE 4145 CONDEMSER
BJK TYPE ed03li>lS PRECISION
SOUMA LEVEL METER
TYP£ UA 02O7
a//r TYPB
AD (3O33 Cfi&LE
TAPE RECORDER
Figure 2.3.3-1. Block Diagram of Recording Instrumentation System
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Noise levels (A-weighted) at locations within the plants,
at the plants' property line, and in the community were
obtained using Bruel and Kjaer precision Sound Level Meters,
Model 2203, 2204, or 2206, using the "slow" damping character-
istic. Model 4145 or Model 4148 Bruel and Kjaer capacitor
microphone cartridges were used as.the electroacoustic
transducer. The above noise level monitoring system was
pre- and post-survey calibrated using either a Bruel and
Kjaer pistonphbne calibrator, Model 4220, or level calibrator,
Model 4230, as applicable.
Recordings of the noise at locations within the plants or
in the adjacent communities were obtained using a Kudelski
Nagra Model IV-B magnetic tape recorder with the Precision
Sound Level Meter Model 2203 or 2204 as its preamplifier,
and microphone, Model 4145 or 4148 as the transducer.
Figure 2.3.3-1 presents a block diagram of the above
instrumentation system. An instrumentation list, Table D-l,
of the noise survey equipment used, including make, model,
and serial number of each unit, is found in Appendix D.
2.3.4 Data Reduction
The information previously recorded on magnetic tape using
the Nagra Model IV-B magnetic tape recorder was retrieved
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by playing the tape back on a Crown 800 Magnetic Tape
Recorder. To insure that the record-playback frequency
response was linear, the signal from the Crown was processed
by a General Radio Type 1925 multifilter. This unit
includes a calibrated attenuator in each of 30 one-third
octave filter channels (25 Hz to 20,000 Hz) which is used
to correct transducer and tape recorder frequency reponse
non-linearities. Table D-2 in Appendix D lists the
attenuator corrections required due to windscreen, micro-
phone, random incidence corrector, sound level meter, and
Nagra/Crown tape recorder non-linearities.
2.3.5 Data Analysis
The recorded data were analyzed in a number of ways using the
General Radio Type 1921 Real-Time Analyzer controlled by
a digital computer. The major components of the analyzer are
the multifilter discussed above and a Type 1826 multichannel
root-mean-square (rms) detector. The detector processed
the signal from the multifilter digitally by sampling the
filter outputs and converting these data to digital binary
form. The binary information is used by a digital processor
to compute rms levels. These outputs, one-third octave band
pressure levels from 25 Hz to 20,000 Hz plus linear, A-weighted,
B-weighted, and C-weighted noise levels are stored in a
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Digital Equipment Corporation PDP-8/I digital computer
for further computation or later printout or punchout
on paper tape.
One-Third Octave Band Frequency Response
The analog signals from the multifilter may be sampled
for periods from 1/8 second to 32 seconds by the rms
detector before computation^of rms levels. The data from
in-plant noise sources were sampled for 32 seconds, except
when ^analyzing noise data with impulsive characteristics
such as chipping hammer bursts—and grinding operations
at the automobile assembly plant. Impulsive data were
sampled for a duration sufficient to include most of the
operation. The one-third octave band sound pressure levels
were printed out, plotted, and are the figures seen in
Section 3. of this report.
Statistical Data Analysis
The analog signals from the multifilter may be sampled
repetitively. That is, the rms detector computes one-third
octave band sound pressure levels from samples obtained
during an integration period. These data are stored while
the detector computes again from samples obtained during the
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next integration period. The sequence of sound pressure
level data thus obtained forms a sampled data set which
is used for statistical computations.
The following procedure was used:
(1) The Real-Time Analyzer was instructed by the
PDP-8/I digital computer to compute 100 groups of
one-third octave band sound pressure level data
points. Each computation was accomplished using
a one-second integration period.
(2) The one-third octave band sound pressure levels
were used by the digital computer to compute octave
band sound pressure levels.
(3) Information from 100 sets of octave band sound
pressure level data was punched on paper tape.
(4) The data stored on paper tape was used as input to
a Statistical Data Analysis program written in
FORTRAN IV programming language.
(5) The Statistical Data Analysis program was used by
an AL/COM time-sharing system to compute and print
put fundamental statistical values and percentile
values.
The fundamental statistical values consist of maximum sound
pressure level, minimum sound pressure level, number of
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occurrences, arithmetic mean, median, and standard
deviation for each octave band. The 10th, 50th, and 90th
percentile levels are computed for each octave band,
linear, A-weighted, B-weighted, C-weighted, and D-weighted.
In addition, the Speech Interference Level (SIL) is
computed. A flow chart of the procedure described above
is presented as Figure D-l. An example of the output format
is reproduced as Figure D-2. Both figures are found in
Appendix D.
Noise Level (A-weighted) Histograms
The Eeal-Time Analyzer was instructed by the PDP-8/I to
compute 50 groups of one-third octave band sound pressure
level data points. Each computation was accomplished using
a four-second integration period. The one-third octave
band sound pressure data were weighted and energy summed to
produce an A-weighted noise level point. The sequence of
these data points was printed out in a histogram format,
an example of which is presented in Figure D-3 of Appendix D.
2.4 Examination of Noise Effects
The in-plant, plant fence line, and neighboring community
noise data in the form of A-weighted noise levels, one-third
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octave band sound pressure levels, and statistical
octave band sound pressure levels were reviewed for an
understanding of the community noise climate, and to
determine whether the industrial plants are the major noise
sources in each community. To aid in understanding the
impact of industrial plant noise, Community Noise Equivalent
Levels* were computed for each community measurement location
from the intrusive A-weighted noise levels observed there.
The actual effects of the industrial noise on community
residents were determined from interviews with city police,
boards of health, plant management, and township officials.
Land use information was gathered from the appropriate state
and local planning departments and zoning maps.
Realizing that the sample size was small (1.5 percent of all
industrial plants were represented), A-weighted noise levels
and community impact information from 22 additional noise-
producing facilities (18 industrial plants) were studied.
Community Noise Equivalent Levels were also computed from
these data.
*Development of CNEL is discussed in the Wyle Laboratories
Contractors' report to Environmental Protection Agency.
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2.5 Noise Abatement Technology Assessment
An assessment of the current state-of-the-art in industrial
noise abatement was constructed. This included appropriate
bibliography, as well as the specific information needed
to evaluate the capability of the present and future efforts
to achieve the level of noise abatement that is required to
meet the various Federal, state, and local noise regulations,
as well as the predicted future requirements. Such an
assessment included:
(1) Presentation by category of machine and environ-
ment of the expected source and environmental
noise reductions that may be achieved through
noise abatement techniques currently in use,
planned, and possible through state-of-the-art
methods.
(2) Outline of the methodology through which noise
reduction can be planned and achieved as a general
methodological technique.
(3) An evaluation of the various program payoffs and
tradeoffs that may be achieved through noise
abatement.
A summary of plans for future noise reduction
including as much information as can reasonably
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be acquired from cooperating industries. Planned
cost allocations are presented where available,
along with estimates of expenditures ovet the
past five years.
(5) Estimates on the potential for noise control of
industrial machines including large machine tools,
air compressors, pumps, industrial trucks, molding
machines, punch pressesT—petrochemical-heaters-,
and waste gas torches.
Referenced in Appendix A, are the technical literature which
formed the basis for the technology assessment. Additional
books, monographs, and papers of interest in this field are
presented in Appendix B as a Selected Bibliography. Current
noise standards and specifications are listed in Appendix C.
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3. FIELD SURVEY RESULTS
The first step in any program to determine the environmental
impact of noise from industrial plants on the surrounding
community should be one of characterizing the plant noise
sources. One must first identify the noise sources, determine
the source noise levels, and describe their frequency domain
characteristics.
From the point of view of noise abatement and control,
industrial noise sources can be classified in a very general
way into the following major types:
(1) Impact noise sources, e.g., punch presses, stamping
machines, and hammers.
(2) Mechanical noise sources, e.g., machinery unbalance,
resonant structures, gears and bearings.
(3) Fluid flow noise sources, e.g., fans, blowers,
compressors, turbines, and control valves.
(4) Combustion noise sources, e. g., furnaces and
flare stacks.
(5) Electromagnetic noise sources, e.g., motors,
generators, and transformers.
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The purpose of the in-plant inspection and survey was to
identify the major noise sources and to obtain acoustical
measurements to determine the character and the noise levels
of these noise sources in order to evaluate their environ-
mental impact on the communities surrounding the industrial
plants.
3.1 Glass Manufacturing Plant
/
Glass bottles are manufactured at this plant by Individual
Section (I.S.) molding machines. The glass, in molten form,
is "blow molded" by the I.S. machine to the required size and
shape. The glassware is cooled and transported by conveyer
to an annealing oven. The finished glassware is then recooled
and transported to quality control inspection stations.
3.1.1 Plant Noise Sources
It became apparent during the plant inspection and survey
that the major source of high frequency noise noticeable
throughout the plant is the discharge of high pressure air.
High pressure air is widely used for pneumatic control and
operation of glass molding machines. This air is generally
vented directly into the atmosphere from cylinder and valve
block ports of glass molding machinery. Turbulent mixing of
the exhaust air with the ambient air is the basic noise-
producing mechanism.
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An analysis of the data obtained in the glass manufacturing
plant showed that the three major noise sources are:
(1) Mold cooling fans,
(2) The blow-molding dies, and
(3) The I.S. machines.
3.1.2 Source Noise Levels
Figures 3.1.2-1 through 3.1.2-3 present the one-third octave
band sound pressure levels for these three sources respectively,
Figure 3.1.2-1 shows the one-third octave band sound pressure
levels measured near the inlet of a typical mold cooling
fan. The fan supplies cooling air to the I.S. machine molds.
These noise levels were measured in a highly reverberant
area of the plant and are typical of the levels expected from
100 to 200 horsepower high pressure fans of this type. The
noise level is 100 dB(A). Fans are the primary source of
noise in air moving systems, and the radiated noise consists
of discrete tones superimposed on a broad-band noise spectrum.
Figure 3.1.2-2 shows the one-third octave band sound pressure
levels one meter from an I.S. machine blow-molding die. .The
noise level is 105 dB(A).
Figure 3.1.2-3 shows the one-third octave band sound
pressure levels measured in the general area of an I.S. Machine.
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This spectrum consists of the sum of the component sources
of the machine. The noise level is 101 dB(A). Collectively,
the I.S. machines are the major noise source within the glass
manufacturing plant contributing to the external plant noise
which affects the surrounding community.
Compressor noise, while not a major sources, does contribute
to the plant noise climate. Figure 3.1.2-4 shows the one-
third octave band sound pressure levels measured in the plant
compressor room.
These noise sources are located within a corrugated cement-
asbestos paneled building containing acoustical louvers at
the air inlets and the air exhausts.
3.1.3 Community Noise Levels
The glass manufacturing plant is located in a small suburban
community with a population of 5,535 persons and a population
density of 2,838 persons per square mile. The residents'
average annual income is $14,240.00. The nearest residential
community to the plant is on a hill adjacent to and overlooking
the plant. Figure 3.1.3-1 is a map of the area which shows
the property line and community measurement locations. All
the measurement locations except Location 13 in the community
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are situated in a residential area where housing units are
of the multifamily type. Location 13 is situated to the
southeast of the plant where housing units are of the single-
family detached type. Figures 3.1.3-2 through 3.1.3-14,
present typical community statistical noise spectra obtained
from both the daytime and nighttime community noise surveys.
The I.S. machines in evidence throughout the plant use a
great deal of air which is presently exhausted without the
use" of mufflers. The broad-band characteristics of this
noise source are in evidence at Locations 1 and 2 and are
the cause of community annoyance. It is known that complainants
reside near Location 1. The nighttime noise at Location 11
contains discrete frequency components in the 125 Hz octave
band, presumably due to local effects such as a neighbor's
air-conditioner or an exhaust fan.
Histograms of noise levels (A-weighted) for daytime and
nighttime for all the community measurement Locations 1
through 13, are presented in Figures 3.1.3-15 through 3.1.3-27,
respectively. The L,Q A-weighted intrusive noise levels for
daytime, evening and nighttime for each measurement at each
community location are shown in Table 3.1.3-1. These Llf>
A-weighted noise levels at each location were energy averaged
and the resulting data were used for computation of Community
Noise Equivalent Level (CNEL) discussed in Section 4.2.4 of
this report.
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The average residual (LgQ) noise levels (A-weighted) at
each measurement location for weekday, weeknight, and week-
end periods are given in Figure 3.1.3-1. It is interesting
to note that the ambient noise levels for Location 2 in the
community are greater than those in other locations. The
reason for this is that Location 2 is very close to the
inlet ventilation ducts at the plant. Note the corresponding
high property line ambient noise levels at Location j.
The statistics of the community noise are represented by
the 90th, 50th, and 10th percentile levels. The 90th per-
centile level, (LQ.), represents a level above which the
noise exists for 90 percent of the time; the 50th percentile
level, (Lcn)/ represents a level above which the noise exists
for 50 percent of the time; the 10th percentile level, (LIQ),
represents a level above which the noise exists for 10 percent
of the time. The 90th, 50th, and 10th percentile values
are considered as representing the ambient, median and intrusive
noise levels, respectively. The LgQ, LS(), and LIQ percentile
values were obtained from 100 data samples.
3-2 Oil Refinery
An oil refinery is a complex system of furnaces, piping systems,
heat exchangers, high pressure vessels, and receiving tanks.
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The noise sources within an oil refinery are furnaces,
compressors, heat exchanger cooling fans, flare stacks,
pumps, control valves, and air and steam piping leaks.
The flare stacks are used to burn excess gases.
3.2.1 Refinery Noise Sources
An analysis of the noise sources identified and measured in
the oil refinery showed that there are two major- types of
noise sources. These are:
(1) The petrochemical furnaces and their associated
air cooled heat exchangers, and
(2) The centrifugal compressor systems.
Furnace noise represents a combination of several noise-
producing mechanisms: first, the noise produced by the
gasified fuel; second, the noise produced by the intake of
primary and secondary air; third, the noise produced by the
combustion process itself. The fuel flow generates high
frequency noise and the air intake system produces a low
frequency noise. Combustion noise is not as significant as
that produced by the air and gas flow.
3.2.2 Source Noise Levels
Figure 3.2.2-1, shows the one-third octave band sound pressure
levels measured near a petrochemical furnace and its associated
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fan-driven, air cooled heat exchangers. The noise level
is 97 dB(A).
There are two basic types of compressors generally used in
oil refineries. The first is the rotary type, such as the
centrifugal and axial compressor where compression takes place
by blades pushing the air much in the same manner as in a
fan. The second type of compressor is the positive displace-
ment type which may be either a piston compressor or a lobe-
type compressor. The sources of noise in both types are
periodic inlet and exhaust pulses resulting in mechanical
noise radiated from the casing of the machine and structure-
borne and fluidborne noise radiated from the discharge piping
system.
Figure 3.2.2-2 shows the one-third octave band sound pressure
levels measured in the oil refinery hydrogen compressor
station between a 2000 horsepower centrifugal compressor and
a 7000 horsepower centrifugal compressor. The noise level
is 98 dB(A) .
The low horsepower of pumps makes them individually minor
noise sources, but collectively they serve to raise the general
noise level in an oil refinery. The one-third octave band
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sound pressure levels of other noise sources such as fin
fans, flares, furnaces, storage tank area, and catalytic
cracking unit are shown in Figures 3.2.2-4 through 3.2.2-8.
3.2.3 Community Noise Levels
The oil refinery is situated within a municipality with a
population of 41,409 persons and a population density of
3.781 persons per square mile. The average annual income
per household is $13,824.00.
The oil refinery is located in a heavily industrialized area
and is bounded on the east, north, and west by highways. The
turnpike going north-south is a heavily travelled major route.
Two separate communities are close to the refinery. To the
south- the refinery is separated from the community by its
oil storage tank farm and to the north it is separated from
the community by a highway which provides access to the turnpike.
Figure 3.3.3-1, shows the measurement locations in the
community and on the plant property line. The residential
areas in the north, where Locations 1, 2, 3, and 4 are situated,
are mainly one- and two-family housing units. The measurement
Locations 5, 6, and 7 are situated in an apartment and tenement
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district separated from the plant by a buffer zone consisting
of a cemetery. The measurement Locations 8.and 9 to the
south of the plant are situated in a residential area consist-
ing mainly of one-family housing units/ mixed with some scattered
business activities.
Figures 3.2.3-2 through 3.2.3-9 represent octave band noise
levels presented statistically for community Locations 2
through 9 respectively. Data for Location 1 was
affected by the presence of a neighboring chemical plant and
is, therefore, not shown. In general, except for Location 5
the daytime (background) ambient noise level represented
by the LgQ curve exceeds the nighttime (background) ambient
noise level. These figures present data consisting of general
broad-band characteristics, which are representative of
industrial areas with, considerable surface transportation.
It is Only isolated instances (LIQ) where traffic may produce
tonal"characteristics, see Figure 3.2.3-4. The major oil
refinery noise sources, see Figures 3.2.2-1 through 3.2.2-8,
are not recognizable as such in the community.
The noise levels (A-weighted) are presented as histograms
for Locations 1 through 9, as Figures 3.2.3-10 through 3.2.3-18
respectively.
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The L,Q A-weighted intrusive noise levels for each measure-
ment at each community location for the daytime, evening,
and nighttime are shown in Table 3.3.3-1. The residual
noise levels at each measurement location in the community
and at the plant property line are given in Figure 3.2.3-1.
3.3 Power Plant
A power plant is a complex, system of furnaces, gas turbine
and steam turbo-generators, transformers,, and associated
equipment. The power plant surveyed contains five steam
turbo—generators and one gas turbine generator. The noise
sources within the power plant are forced draft blowers,
control valves, induced draft fans, compressors, transformers,
and the turbine generators themselves.
3.3.1 Plant Noise Sources
Turbines, both gas and steam, are major sources of noise in
power plants. The major noise sources in a typical gas
turbine driven compressor installation are the compressor
piping, compressor vibration, exhaust duct radiation, shell
radiation, the turbine exhaust and the gassturbine inlet.
The gas turbine inlet is the loudest and most annoying noise-
producing mechanism, because of its characteristic high frequency
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whine corresponding to the blade passage frequency of the
first stage of the compressor. The gas turbine exhaust is
lower in frequency and sounds more like the noise produced
by a jet aircraft during take-off.
A considerable amount of noise is radiated from the generator
casing. The turbine exhaust shroud also radiates a large
amount of exhaust noise. In addition, there is some noise
radiated by the turbine housing, and when the entire unit is
mounted on a structural steel framework there may be a
considerable amount of structureborne noise transmitted from
the machinery to the framework.
Fluidborne and structureborne noise transmitter to piping
systems and other associated equipment may be major sources
of power plant noise. This noise is radiated by the piping,
floors, walls, and ceilings unless corrective measures to
block its transmission path are accomplished.
3.3.2 Source Noise Levels
•An analysis of the data obtained in the power plant showed
that the three major noise sources are:
(1) Draft fans (both induced and forced-type),
(2) Turbine generators, and
(3) Air compressors.
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Figures 3.3.2-1 and 3.3.2-2 present the one-third octave
band sound pressure levels measured between two induced
draft fans and near a forced ^iraft fan outside the main power
plant building, respectively. In forced draft fan systems,
the fan inlet is the major source of noise. The fan noise
spectra are combinations of broad-band and discrete noise.
The discrete noise shows up as pure tones at multiples of the
fan rotational frequency. These1 spectra are typical for these
fan types and are a function of the mechanical construction
and the aerodynamic forces of the fan. The noise levels are
68 dB(A) for the induced draft fan and 96 dB(A) for the forced
draft fan.
Figure 3.3.2-3 shows the one-third octave band sound pressure
levels measured near a 100 megawatt steam turbine generator.
The noise level is 93 dB(A).
Figure 3.3.2-4 shows the one-third octave band sound pressure
levels measured in the compressor room area. The noise level
is 97 dB(A) .
3.3.3 Community Noise Levels
The power plant is located in a rural community which borders
it to the west and south. To the east is a river, and to the
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north is an oil refinery (not the refinery discussed in
Section 3.2). The power plant lies in a municipality
whose population is 98,944 persons with a population density of
4,283 persons per square mile. The average annual income
per household is $10,951.00.
The measurement locations in the community and on the plant
property line are shown in Figure 3.3.3-1. The power plant
is located in a heavily industrialized area of the community.
The measurement Locations 1 through 8 in the community are in
a residential area consisting of single-family detached housing
units mixed with some scattered neighborhood business centers.
Community noise levels for Locations 1 through 8 are presented
as statistical noise spectra in Figures 3.5.3-2 through
3.5.3-9 respectively.
The noise spectra for two Locations, 1 and 6, indicate
that broad-band noise predominates, while the noise spectra
for Locations 3 and 5 indicate that the background contains
discrete frequency noise during the day at Location 3, and
during the night at Location 5. The low frequency noise
evident inside the power plant is not evident in the community
data. The noise in the 125 Hz band at Location 5 and in the
250 Hz band at Location 3 may be due to local effects such
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as air-conditioners, basement workshop equipment, etc.
Figures 3.3.3-10 through 3.3.3-17, show the daytime and
nighttime histograms of A-weighted noise levels for community
Locations 1 through 8 respectively. The LIQ A-weighted
intrusive noise levels for each measurement location for
the daytime, evening, and nighttime are shown in Table 3.3.3-1.
The residual noise levels at each measurement location in the
community and on the property line are given in Figure 3.3.3-1.
3.4 Automobile Assembly Plant
The automobile assembly plant assembles standard-size cars
and small trucks. Employees use, as labor assist devices,
pneumatic and electric powered hoists,and 3tools such as
grinders, impact wrenches, angle wrenches, and hole saws.
Also, body painting and body cleaning operations use air blow-
down devices. The noise created by pneumatic tools is airborne,
and the major noise source is the tool air exhaust.
3.4.1 Plant Noise Sources
An analysis of the noise sources identified and measured in
the automobile assembly plant indicates that three operations
using pneumatic tools may be classified as major noise sources.
These three operations are:
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(1) The rough grinding operations,
(2) The weld destruct operation by chipping, and
(3) The piercing and hole cutting operation.
In addition, forced air blowers and air compressors are
major in-plant noise sources.
There are three broad classifications of pneumatic tools:
rotary, piston, and percussion type. In a typical pneumatic
tool, the air passes through the handle, past a control valve,
through end plates, and into a chamber in the cylinder where
it presses against blades that are free to slide in the slots
of a rotor. As the air expands against the blades, the rotor
turns until exhaust ports are passed in the cylinder, allowing
the air to discharge into the atmosphere. Percussion tools
such as the chipper are the noisiest of all pneumatic tools.
However, the very act of grinding and chipping on a large
metal object will create more noise than the actual tool
itself. The combination of tool and operation noise covers
a broad-band, but the levels are greatest in the high frequency
bands.
3.4.2 Source Noise Levels
Figure 3.4.2-1 presents the one-third octave band sound
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pressure levels measured near a rough grinding operation.
The noise level is 108 dB(A). Figures 3.4.2-2 and 3.4.2.3
present the sound pressure spectra for the weld destruct
chipping operation and the piercing and hole cutting operation^
The noise levels are 115 dB(A) and 109 dB(A) respectively.
Figure 3.4.2-4 presents the one-third octave band sound
pressure levels measured near a forced draft air blower. The
noise level is 98 dB(A) .
Figure 3.4.2-5 presents the one-third octave band sound
pressure levels measured near two reciprocating compressors.
The noise level is 94 dB(A). Figure 3.4.2-6 presents the
one-third octave band sound pressure levels measured near
a typical air blow-off operation. .The noise level is 102 dB(A).
Figures 3.4.2-7 through 3.4.2-12 present the one-third octave
band sound pressure levels of blow-off operations, pneumatic
tools and metal finishing operations.
3.4.3 Community Noise Levels
The automobile assembly plant is bounded on the west by a
major highway and on the east by a suburban community with
a population of 10,539 persons, with a population density of
410 persons per square mile. The average annual household
income for this community is $13,441.00.
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The community is adjacent to the rear of the plant. At the
rear, but still a part of the plant, are railroad switching
tracks used to bring preassembled parts into the plant.
These parts are stored in an area between the plant's rear
and the assembly floor where the major noise sources are
located. The plant operates on a two-shift basis, with
assembly operations halted for maintenance and clean-up
after midnight.
The measurement locations in the community and on the plant
property line are shown in Figure 3.4.3-1. The automobile
assembly plant is located in an industrial area. AL1 the
measurement locations 1 through 9 are situated in a residential
community consisting of single-family detached housing units
mixed with some scattered business activities.
Community noise for the Locations 1 through 9 are presented
as statistical noise spectra in Figures 3.4.3-2 through 3.4.3-10
respectively. These spectra are not directly relatable to
the major noise sources within the plant. Some of this noise
is due to the railroad operation at the rear of the plant.
The discrete frequency components in evidence at Locations 3,6,
and 7 (See Figures 3-4-3-4, 3.4.3-7, and 3.4.3-8) in the 125 Hz
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Octave band may be due to local effects such as window
exhaust fans of air-conditioners, while the discrete frequency
in evidence in the 4000 Hz octave band at nighttime Location 8
may be due to insect noise.
The noise levels (A-weighted) are presented as histograms
for Locations 1 through 9 for the daytime and nighttime on
Figures 3.4.3-11 through 3.4.3-19. The L.Q A-weighted
intrusive noise levels for each measurement location for
the daytime, evening, and nighttime sampling periods are
shown in Table 3.4.3-1. The ambient noise levels at aaah
measurement location in the community and on the property
line are given in Figure 3.4.3-1.
3.5 Can Manufacturing Plant
The process of can manufacturing requires metal forming and
metal cutting, e.g., punching, shearing, pressing, and
soldering. Metal fabricating operations and their associated
equipment are in general noisy. Noise radiating from the
noisy operations is transmitted throughout the reverberant
plant building. This may mean that an employee performing
a relatively quiet operation at one end of the plant may be
exposed to noise from a noisy operation at the other end of
the plant.
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3.5.1 Plant Noise Sources
An analysis of the noise sources identified and measured
in the can manufacturing plant indicates that the three
major noise sources are;
(1) The air compressor system,
(2) The ring pull punch presses, and
(3) The internal lacquer spray line.
Among the other sources that contribute to the in-plant noise
are body maker slitters, different types of punch presses,
flangers, air test system, beaders and seamers.
3.5.2 Source Noise Levels
Figure 3.5.2-1 presents the octave band sound pressure levels
measured at the air compressor section of the plant. The
noise level there is 99 dB(A).
Figure 3.5.2-2 presents the octave band sound pressure levels
measured near a ring pull punch press. The noise level is
104 dB(A) .
Figure 3.5.2-3 presents the octave band sound pressure levels
measured near the internal lacquer spray line. The noise
level is 103 dB(A). Figures 3.5.2-4 through 3.5.2-11 describe
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the octave band sound pressure levels of other sources
that contribute to the total noise within the plant. The
data presented in Figures 3.5.2-1 through 3.5.2-11 have been
obtained from a noise survey report* as permission was
not received for an in-plant noise survey.
3.5.3 Community Noise Levels
The can manufacturing plant operates on a three-shift basis
and is located within an industrial area of a moderately
large city. This city's population is 144,824 persons, with
a population density of 17,159 persons per square mile. The
average household income for residents is $10,198.00.
The can manufacturing plant is located in a heavily industrialized
area. Figure 3.5.3-1 is a map of the community surrounding
the can manufacturing plant. The residential area adjacent
to the plant consists mainly of two- and three-family housing
units. The residual noise levels (A-weighted) in the community
(Locations 1 through 10), and on the property line of the plant
(Locations a-j), for the weekend, weekday, and weeknight are
given in Figure 3.5.3-1.
Though there are no major highways presently operating nearby,
the, streets are heavily travelled by bus, trucks, and automobiles.
*"Noise Survey Report," Liberty Mutual Insurance Company,
12 June 1970.
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The community noise is presented in Figures 3.5.3-2 through
3.5.3-11 as statistical noise spectra for Locations 1 through
10. These spectra are representative of what might be
expected in an urban industrialized community. The noise of
the can manufacturing plant is occasionally discernable at
locations approximately one-half of a city block from the
plant, but is masked much of the time by surface transportation
noise.
Histograms of noise levels (A-weighted) for the same locations
indicated above are presented in Figures 3.5.3-12 through
3.5.3-21.
The LIO A-weighted intrusive noise levels for each measure-
ment location for the daytime, evening, and nighttime sampling
periods are shown in Table 3.5.3-1.
The ambient noise levels at each measurement location in the
community and on the property line are given in Figure 3.5.3-1.
-53-
-------
2
a>
o
10
D
CO
s
o
0)
c
o
X
dB(A)
31.5
.1
125
290
I
100
500
—U
1000
-I-
tooo
4000
woo
MOOD
1000
10000
Frequency in Hz
Figure 3.1.2-1
One-Third Octave Band Sound Pressure
Levels Measured near the Inlet of an
I.S. Machine Mold Cooling Fan in a Glass
Manufacturing Plant.
-54-
-------
-o
o
CD
U
O
-o
6
CN
-------
£
i
2?
a.
O
CO
0)
a
"o
O
0)
6
*?
£
CO
TJ
V
0)
no
100
90
80
70
60
50
31.5
.1
63
-J-,
125
25O
I
500
IOOO
20OO
4000
•000
WOOD
100
4-
1000
10000
Frequency in Hz
Figure 3.1.2-3. One-Third Octave Bond $ound Pressure
Levels Measured near One I.S. Machine
in a Glass Manufacturing Plant.
-56-
-------
110
£
10
A
OQ
o
CO
4)
I
o s
-e r
6
60
50
dB(A)
Figure 3.1.2-4.
Frequency in Hz
One-Third Octave Band Sound Pressure
Levels Measured in the Air Compressor
Room of the Glass Manufacturing Plant.
-57-
-------
'<\
Scale
OgOO (000 «X>
-------
•0 «f)
§ 'o
o -r;
-a
o
ea
a
o
"u
O
2
co
-o
c
70
60
50
40
30
20
100
10000
1000
Frequency in Hz
Figure ?3i\1.3-2. Glass Manufacturing Plant Location I.
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. L9Q/ LSQ, and L|Q Percentile Values were Obtained from 100 Samples
with One Second Integration Time.
Daytime
Nighttime
-59-
-------
E
I I
O -£
4/1 CN
-------
.3
I
to
•g
I
o
CQ
TJ
50
40
30
20
100
Figure 3.1.3-4.
1000
Frequency in Hz
Glass Manufacturing Location 3
10000
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. LQQ, L50/ and L-0 Percentile Values were Obtained from 100
Samples with One Second Integration Time.
Daytime
Nighttime
-61-
-------
-------
!»*
8 '2
0)
I
o
ca
-a
80
70
60
50
40
30
20
Figure 3.1.3^6.
Frequency in Hz
Glass Manufacturing Plant Location 5
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. Ion/ Len/ ana< LJA Percentile Values were Obtained from 100
Samples with One Second Integration Time.
Daytime
*- Nighttime
-63-
-------
ji
2
S» F
|wl
§ '?
-------
3
£
3 CM
I
£
CQ
•o
c
I
O
80
70
60
50
40
30
20
^
XX%
\V
[90
[50
L10
31.5
63
125
250
I
500
-4—
1000
4-
2000
I
4000
NOOO
10000
100 2 5 1000 *
Frequency in Hz
Figure 3.1.3-8. Glass Manufacturing Plant Location 7
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. LOQ/ L,.-, and Lin Percentile Values were Obtained from TOO
Samples with One Second Integration Time.
Daytime
Nighttime
-65-
-------
20
Figure 3, U3-*9.
Frequency in Hz
Glass Manufacturing Plant Location 8
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. Log, L5Q/ and L]Q Percentile Values were Obtained from 100
Samples with One Second Integration Time.
Daytime
Nighttime
-66-
-------
V
0>
o
in
Ǥ
u
O
CO
-o
c
50
40
30
20
100
Figure 3.1.3-10.
1000
Frequency in Hz
Glass Manufacturing Plant Location 9
10000
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. Log/ L5&f and L,Q Percentile Values were Obtained from 100
Samples with One Second Integration Time.
Daytime
Nighttime
-67-
-------
£
D CM
1 '2
O X
OO CM
c
O
OO
-------
1
2
3 CM
a .£
£ >
Ou £-
O
A
-------
0)
2
8
0)
1
U
O
"x
CN
03
T3
80
70
60
50|
40
30
20
100
10000
1000
Frequency in Hz
Figure 3.1.3-13. Glass Manufacturing Plant Location 12.
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. LOQ, LJJQ, and L|Q Percentile Values were Obtained from 100 Samples
with One Second Integration Time.
Daytime
— Nighttime
-70-
-------
0)
§
CM
0
10
TJ
I
0)
I
u
o
I
2
CO
-o
40
30
20
OO
Figure 3.1.3-14,
1000
Frequency in Hz
Glass Manufacturing Plant Location 13
0000
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. Lon, LCQ, and L, - Percentile Values were Obtained from 100
Samples with One Second Integration Time.
Daytime
Nighttime
-71-
-------
E
*
.
5
<•
a*
CQ
-O
.s
"w
Jl
O
.**
"5
^•••••t
?
_E
.2*
"5
^
40 **
41 *
42
43
44 *
45 ***
46
48 **
49 *************
50 *******
51 *****
52 ****
53 ***
54 *
55 **
56 *
57
58
59 **
60 **
61
62
63
64
65
Number of
Occurrences
Daytime
1
o
CM
w
CQ
C
*~
5
JS
a>
*o
Z
"8
_E
,O>
4|
<
40
41
42
43
44 *
45
46
47 ****
48 ***
49 **
50 ****
51 ****
52 ****
53 ***
54 *
55 *
56 *
57 *
58 *
59 **
60
61
62
63
64 **
65
****************
Number of Occurrences
Nighttime
j
Figure 3.1.3.15. Glass Manufacturing Plant Ideation 1.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-72-
-------
1
********************
*******************
******
Number of Occurrences
Daytime
ca
TJ
-------
CO
c
f
.5?
"5
40
41
42
43
44
45
46
47
48
49
50
*******
******************************
***********
**
2
03
Number of Occurrences
Daytime
|
<
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
**
*****************************
******************
Number of Occurrences
Nighttime
Figure 3.1.3-17. Glass Manufacturing Plant Location 3.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-74-
-------
o
A
2
35
N-
1
1
o
<>s
£
ca
TJ
C
*^
1
J3
S
wv
"o
Z
1
.5?
*S
j*
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
*
**
********
***************
********
******
**
*****
*
*
*
% 36
c 37
II 38
£ 39 *
_o 40 ****
0 41 **************************************
•5 42
Z 43
TJ 44
I 45
.5*
"5
Number of Occurrences
Daytime
Number of Occurences
Nighttime
Figure 3.1.3-18. Glass Manufacturing Plant Location 4.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-75-
-------
CM
^_
I
o
5
2
CQ
JC
KM
5
JS
-------
CM
^
co
TJ
45
46
47
48
49
50
51
52
53
54
55
*******
2
CO
-o
c
**
******************************* —
o
o>
I
Number of Occurrences
Daytime
a>
4
40
41
42
43
44
45
46
47
48
49
50
*************
*************************
***********
Number of Occurrences
Nighttime
Figure 3.1.3-20. Glass Manufacturing Plant Location 6.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-77-
-------
«o
5
ID
cS
40 *
41 **
42
43
44 ****
45 ***********
— 46 ***********
J 47
^ 48 ******
49 *****
® 50
&
co
-o
c
*~
?
JS
1
•D
•^
40
41
42
43
44
45
46
47
48
49
50
<
Number of Occurrences
Daytime
****
*********************
******************
*******
Number of Occurrences
Nighttime
Figure 3.1.3-21* Glass Manufacturing Plant Location 7.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-78-
-------
I 40
o 41
00
•o
***********
42 *****************
43
44 ****
45
.£ 46
S 48
3 49 *
8 50 *
51
52 **
53
o
5
2
eo
TJ
ID
5
u»
*O
*5 55
3
<
Number of Occurrences
Daytime
40
41
42
43
44
45
46
47
48
49
50
*******
*********************
***************
*****
**
Number of Occurrences
Ni^itrime
Figure 3.1.3-22.Glass Manufacturing Plant Location 8.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-79-
-------
**
CN
£
eo
~o
2
0)
0
I
50
51
52 *
53 *
54 *
55
*
****
Number of Occurrences
Nighttime
Figure 3.1.3-23. Glass Manufacturing Plant Location 9.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-80-
-------
o
o$
£
eQ
C
•"""
J
.3
8
"o
Z
1
Jn
.2*
*S
I
40 **
41 ****
42 **
43 *
44
45
4g ********
47 ****
4g ******
49 ********
50 *******
51 **
52 *
53 *
54
55
56
57 **
58 *
59
60
61 *
62
63
64
65
co
-o
JC
1
0>
-------
35
36
CN 37
38
39 ***
40 ***********
41 *******
42 *****
43 ***
44 **
45 *
46 **
47 ***
48 ***
49 **
50 ****
51
52 *
53
54
55
56 *
57
58 *
59 *
60
£
co
-o
c
o
^m
«J
—
"o
I
"ro
"5
^
<
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
'^•P
5V
60
61
62
63
64
65
66
67
68
69
70
71
72
73
*
*
*
**
*
****
***
******
****
***
****
******
****
***
*
*
**
Number of Occurrences
Da/time
Number of Occurrences
Nighttime
Figure 3.1.3-25. .Glass Manufacturing Plant Location 11.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-82-
-------
£
S-
1
0
1&
£
03
TJ
,c
I
M
1
0)
.5*
*S
;>
<
40
41
42
43
44
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
*
***
*
*
*
*
**
****
**
****
**
*
***
*
***
***
***
***
**
*****
*
*
*
*
**
CM
1
00
-o
5
JS
0)
o>
Number of Occurrences
Daytime
**********
40
41
42
43
44 *
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 *
Number of Occurrences
Nighttime
Figure 3.1.3-26. Glass Manufacturing Plant Location 12.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-83-
-------
CM
eo
-o
c
(O
IT)
.S?
*3
40
41
42
43
44
45
46
47
48
49
50
**********
********************
*********
******
****
Number of Occurrences
Daytime
o
s
2
ca
TJ
.5?
°3
40
41
42
43
44 **
45 ********
46
47 ***********
48 ***********
49 *****
50
Number of Occurrences
Nighttime
Figure 3.1.3-27. Glass Manufacturing Plant Location 13.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-84-
-------
Table 3.1.3-1 - Intrusive (l} 0) Noise Level (A-Weighted) Observed at
Glass Manufacturing Plant Community Locations During
Day, Evening, and Nighttime Sampling Periods
Noise Level dB(A)
Noise Level dB(A)
Location
1
2
3
4
5
6
7
Day
56
56
54
61
59
63
51
45
46
51
54
46
44
42
50
43
47
55
49
48
Evening
53
56
61
61
46
45
48
49
42
62
45
45
Night
66
52
60
66
48
5^
42
42
47
48
45
45
46
Location Day Evening
8 SQ. 44
45 47
44
9 45 46
52
45
10 §5 48
48
57
11 52
51
12 55
64
63
13 53
44
Night
44
45
46
46
50
58
48
50
41
54
54
52
53
44
49
-85-
-------
o
"S
I
0)
6
100.
90
80
Z 70
Q>
CO
0)
60
50
40
31.5
dB(A)
125
230
100
Figure 3.2.2-1
500
—I—
1000
-J-
2000
4000
1000
8000
4-
16000
10000
Frequency in Hz
One - Third Octave Band Sound Pressure
Levels Measured Near a PetrochemicaJ
Furnace in an Oil Refinery.
-86-
-------
Ifl
-o s
c
o
-------
§
1 "
o
•g '
5
5
o
O
CO
c
"2 II
„
O
100
90
80
70
60
50
- , dB(A)
500
IOOO
20OO
4000
100
IOOO
Frequency in Hz
•000 WOOD
10000
Figure 3.2.2-3. One-Third Octave Band Sound Pressure
Levels Measured Near a Fin Fan in an Oil
Refinery.
-88-
-------
0
3
CM
1
•
O
CO
4>
I
u
O
~z
IE
6
CO
T3
100
90
80
70
60
50
40
V
31.5
63
125
250
L_
500
100
1000
4-
200O
4000
8000
5 1000
Frequency in Hz
4-
16000
L_
,, dB(A)
10000
Figure 2.3.2-4. One-Third Octave Band Sound Pressure
Levels Measured in Storage Tank Area
in an Oil Refinery.
-89-
-------
£
3
1*0
o •—
CO X
U
O
o>
6
£
CO
-o
100
90
80
70
60
50
40
7
( dB(A)
3I.S
.1
63
125
_L_
zso
I
100
500
-4-
tooo
2000
4000
8000
WOOD
1000
I 0000
Frequency in Hz
Figure 3.2.2-5. One-Third Octave Band Sound Pressure
Levels Measured Between Two Flare Stacks
and Near furnaces; (Pentone Units) in an
Oil Refinery.
-90-
-------
£
IT)
* &
I f
0 1
0)
6
I
100
90
80
70
60
50
40
dB(A)
\
31.5
63
-4-,
125
250
I
500
too
1000
4-
2OOO
4000
•000
nooo
1000
I 0000
Frequency in Hz
Figure 3.2.2-6. One-Third Octave Band Sound Pressure
Levels Measured Near a Catalytic Cracking
Unit in an Oil Refinery.
-91-
-------
£
3 -o
•g 2
£
0)
I
o «
O c
£
co
5
0)
V
6
10000
Frequency in Hz
Figure 3.2.2-7. One-Third Octave Band Sound Pressure
Levels Measured Near a Cabin-Type
Furnace (Alcorn) in an Oil Refinery.
-92-
-------
I
o
0)
CQ
-o
100
90
80
70
60
50
40
r
31.5
63
125
250
I -
500
1000
2OOO
4000
8000
100
1000
WOOD
L_
dB(A)
10000
Frequency in Hz
Figure 3.2.2-8. One-Third Octave Band Sound Pressure
Levels Measured Between Fin Fan Array
and Cabin-¥ype Furnace in an Oil Refinery.
-93-
-------
Weekend
Weekday
Weeknight
Weekend
Weekday
Weeknight
Community Noise Levels in dB(A)
1 23456789
59 49 52 55 50 50 50 48 51
63 52 50 56 48 51 54 47 50
60 51 51 50 47 49 59 47 49
Plant- Property Line Noise Levels in dB(A)
abcdefghi
55 71 60 60 60 55 54 52 56
63 68 60 62 64 63 51 52 53
58 67 59 59 .62 61 49 50 54
Industrial Noise Source
Residential Area
Railroad Track
Highway
Measurement Location
•5000
Figure 3.2.2-1.
Oil Refinery Community
-94-
-------
.3
£
2 CM
•j s
s «
1 -£
o
0
100
Figure 3.2.3-2.
2 s |ooo
Frequency in Hz
Oil Refinery Location 2
10000
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. Lo0/ L5Q/ and LIO Percent!le Values were Obtained from 100
Samples with One Second Integration Time.
Daytime
Nighttime
-95-
-------
Q>
in
o5
•g 'o
8 3
-o 2
O CO
CO -o
£
o
o
30
I 0000
Figure 3.2.3-3.
Frequency in Hz
Oil Refinery Location 3
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. LQQ, L5Q/ and LIQ Percentile Values were Obtained from 100
Samples with One Second Integration Time.
Daytime
._»_-. Nighttime
-96-
-------
CM
•o
o
to
TJ
I
(U
I
O
I
X
-------
0>
4)
0>
CM
o o
00 ~x
-0
-------
30
100
1000
10000
Frequency in H2
Figure 3.2.3-6. Oil Refinery Location 6.
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. L^Q, L$Q, and L|Q Percentile Values were Obtained from 100 Samples
with One Second Integration Time.
Daytime
— —— Nighttime
-99-
-------
0)
0)
CM
O
O
CQ
0)
O
X
CN
0
CQ
~D
40
30
2 5 100 2 » 1000 2 5 | 0 600
Frequency in Hz
Figure 3.2.3-7. Oil Refinery Location 7.
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
•Surveys. L.90, LSQ, and L|Q/Percentile Values were Obtained from 100 Samples
fj One Second Integration Time.
— Daytime
— Nighttime
-100-
-------
I $
8
V)
TJ
I
I
u
O
£
00
90
80
70
60
50
40
30
2000 Ntooo eooo
100
Figure 3.2.3.-S,
1000
Frequency in Hz
Oil Refinery Location 8
10000
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. L90/ LCQ, and L1Q Percent!le Values were Obtained from 100
Samples with One Second Integration Time.
Daytime
Nighttime
-101-
-------
I
2
"
* f
1 -o
8 'o
to
V
CO
> "^
s .c
O "~
O
90
80
70
60
50
40
30
100
Figure 3.2.3-9.
1000
Frequency in Hz
Oil Refinery Location 9
10000
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. LoQf L5Q/ and L1Q(Percentile Values were Obtained from 100
_50/ 1Q(
Samples with One Second Integration Time.
Daytime
Nighttime
-102-
-------
E
f\
Ej
'o
A
V
CO
•o
c
*••>
"3
.3
o
«
"o
z
"8
oj
4)
?
<
60
61
62
63
64
65
66
67
68
69
70
******************
*************
********
***
**
Number of Occurrences
Daytime
I
£
ea
•u
c
.8
"o
z
£
O)
60
61
62
63
64
65
66
67
68
69
70
i
<
**************
******
***********
*****
***
****
Number of Occurrences
Nighttime
Figure 3.2.3-10. Oil Refinery Location 1.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-103-
-------
CM
Is,
0 51
~ 52
cQ 53
2 54
T3 55
c 56
I! 57
S> 58
JJ 59
<|) 60
•5 61
Z 62
~g 63
£ 64
.S> 65
0
******
******
**
*****
***
*****
******
**
****
*********
**
Number of <
CM
1
"O
1 o
c5
2
CO
-o
•-
1
J3
*<5
T
<
40 **
41 *
42
43
44 *
45
46 **
47
48 ****
49 *********
50 ********
51 **
52 ***
53 **
54 ****
55 ***
56
57 *
58
59 ****
60 *
61 *
62 **
63
6A
65
Daytime
Number of Occurrences
Nighttime
Figure 3.2.3-11. Oil Refinery Location 2.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-104-
-------
^
o
A
1
>
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
**
**************
**********
****
*****
*
**
*
*
*
*
Number of Occurrences
Daytime
"Z
CN
2
to
-0
c
^_
§>
0)
8
••£
o
Z
_c
.s?
*55
45
46
47
48
49
50
51
52
53
54
55
******************
*******
***
Number of Occurrences
Nighttime
Figure 3.2.3-12. Ofl Refinery Location 3.
Noise Level (A-We?ghted) Histogram 50 Samples Four Second
Integration.
-105-
-------
N
•9Z
O
<3
^
^
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
*
***
***
*******
****
*******
*****
****
***
***
**
**
****
**
CN
1
''o
"x
V*
D
• CO
JC
^_
-------
CN|
VI
NE
V
m
0
x
0
u
CD
•o
c
"3
5>
-i
0
i
"8
-X
'5
>
<(
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
**
**
**
**
**
**
*
**
*
*
**
*
2
CQ
§2
J3
$
***************
o>
I
Number of Occurrences
Daytime
45 *******
46 ****
47 *************
4g ******
49 ************
50 **
51 *
5£ ***
53 *
54 *
55
Number of Occurrences
Nighttime
Figure 3.2.3-14. Oil Refinery. Location 5.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-107-
-------
01
\
r
0
3
2
-a
^c
~w
Q>
--1
8
^
^
J
"o>
"5
2>
<
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
*
**
**
*
**
*****
**
*****
********
***
********
*
****
**
*
***
01
vs
O!
£
CO
-a
£
^MK
>
JJ
O
CA
%p*
"o
Z
2
_C
O)
"5
^
<
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
****
*****
******
**
****
****
******
**
**
****
**
**
*
**
*
**
*
Number of Occurrences
Daytime
Number of Occurrences
Nighttime
Figure 3.2.3-15. Oil Refinery Location 6.
Noise level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-108-
-------
•?
' E
*
o
5
CN
I
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
********
*******************
*********
**
*******
**
***
Number of Occurrences
Daytime
Number of Occurrences
Nighttime
Figure 3.2.3-16. Oil Refinery Location 7.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-109-
-------
in
*O
Z
_£
O)
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
**********
******************
****
**
***
Number of Occurrences
Daytime
0)
CO
-o
JS
0)
.52
O
O)
40
41
42
43
44
45
46
47
48
49
50
***
*******************
***************
*************
Number of Occurrences
Nighttime
Figure 3.2.3-17. Oil Refinery Location 8.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-110-
-------
IO
I
v
CJ
£
ca
"O
c
•••1
1
J3
0)
.2
*o
Z
"8
^
3
m
*o
3
.5?
'5
=r
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
**•
**
**'
**
**
**
**
*
*
*
**
**
* * * * *•* * »c * * * * * * *
Number of Occurrences
Nighttime
Figure 3.2.3-18. Oil Refinery Location 9.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-Ill-
-------
Table 3.2.3-1 - Intrusive (L10) Nofse Level (A-Weighted)Observed at Oil
Refinery Community Locations During Day, Evening, and
Nighttime Sampling Periods
Location
Noise Level dB(A)
Day Evening Night
Location
Noise Level d,B(A)
Day Evening Night
1
2
3
4
5
72
64
73
60
61
62
50
5¥
59
66
63
68
58
62
49
66
74
72
54
55
58
63
61
55
56
64
61
57
52
55
60
61
61
57
66
65
59
58
47
57
58
64
51
55
50
6
7
8
9
63
56
78
70
66
74
73
56
53
58
61
57
58
67
65
54
64
65
54
53
56
69
60
60
54
57
48
48
53
50
48
50
53
51
55
54
59
-112-
-------
i
V
l"i
co i
0
£0
I
o
0
_c
c
0
X
CM
CD
•o
O
V
no
100
90
80
\
70
60
50
31.5
• 3
It5
250
I
500
1000
tooo
—J—
4000
—I—
•000
100
Figure 3.3.2-1
s 1000
Frequency in Hz
One-Third Octave Band Sound Pressure
Levels Measured 'hear Two Induced
Draft Fans in a Power Plant.
10000
wooo
-L_
-113-
-------
0)
I/I
w>
0)
CN
-o
o
CO
0)
o
u
o
TZ
IE
i—
0)
6
no
100
90
x
CM
0)
CO
(D
80
70
60
50
v
dB(A)
3(.5
I
IZS
I
230
ft.'-.'
1000
tooo
I
4000
•000
WOOD
100
Figure 3.3.2-2.
^ 1000 2 9
Frequency in Hz
One-Third Octave Band Sound Pressure
Levels Measured near a Forced Draft
Fan Inlet in a Power Plant.
10000
-114-
-------
0)
1
0- CN
11
0 M)
«/> I _
d>
O
t;
0
5
IE
6
X
CN
OQ
•a
<0
dB(A)
100
Figure 3.3.2-3.
Frequency in Hz
One-Third Octave Band Sound Pressure
Levels Measured near a Steam Turbine
Generator in a Power Plant.
-115-
-------
£
I
8 vJ
' ,
-o
o
CO
0)
o
"o
no
100
90
"x 80
CN
CO
-o
«>
6
70
60
50
t»o
i
800
1000
1000
I
4000
•000
wooo
I
100
Figure 3.3.2-4.
' 1000 * » 10000
Frequency in Hz
One-Third Octave Band Sound Pressure
Levels Measured in the Compressor Room
in a Power Plant.
dB(A)
-116-
-------
Weekend
Weekday
Weeknight
Weekend
Weekday
Weeknight
Key
Community Noise Levels in dB(A)
1 2345678
48 50 50 50 52 58 57 54
48 51 49 53 55 56 55 54
51 52 52 52 53 56 57 54
Plant Property Line Noise Levels in dB(A)
abcdefghi
81 58 63 69 64 53 54 59 68
64 59 61 72 80 61 59 57 63
68 63 67 70 80 61 60 61 65
Industrial Noise Source
Residential Area
Railroad Track
Highway
Measurement Location
Figure 3.3.3-1,
Power Plant Community
-117-
-------
I
I
ifi CM
I
"
D
CO
o
t>
O
X
«
40
30
100
10000
2 5 1000 2
Frequency in H2
Figure 3.3.3-2. Power Plant Location I.
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. L9Q/ I-59/ and L|Q Percentile Values were Obtained from 100 Samples
with One Second Integration Time.
Daytime
— -— Nighttime
-118-
-------
5
.3
S
o •::
CO
?
O
t)
0
CQ
100
Figure 3.3.3-3.
1000
Frequency in Hz
Power Plant Location 2
10000
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. LOQ, L5Q, and L]0 Percent!le Values were Obtained from 100
Samples with One Second Integration Time.
Daytime
Nighttime
-119-
-------
0)
0)
0)
3
CM
3 1C
O I
t/> O
2 s
O
c
• «
90
80
70
60
50
40
30
100
5 |000 2
Frequency in Hz
10000
Figure 3.3.3-4.. Power Plant Locations.
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. L-9Q, LgQ, and L|Q/ Percentile Values were Obtained from 100 Samples
with One Second Integration Time.
Daytime
Nighttime
-120-
-------
1
«
CM
I
o
0
30
100
Figure 3.3.3-5.
1000
Frequency in Hz
Power P.la«t-4o6€ri4en-4-
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. LOQ, L50' and L10 Percentilc Values were Obtained from 100
Samples with One Second Integration Time.
Daytime
Nighttime
-121-
-------
Q)
0)
3
o
X
CN
0)
CD
.£
o
o
90
80
70
60
50
40
30
too
10000
2 5 \000
Frequency in Hz
Figure 3.3.3-6. Power Plant Location 5.
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. LOQ/ L^Q, and L|Q Percentile Values were Obtained from 100 Samples
with One Second Integration Time.
Daytime
Nighttime
-122-
-------
90
100
10000
Yobo
Frequency in Hz
Figure 3.3.3-7. Power Plant Location 6.
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. LOQ, LSQ, ofirf L|Q Percent!le Values Obtained from 100 Samples
with One Second Integration Time.
——— Daytime
—f— — Nighttime
-123-
-------
£
8
to
TJ
I
£
u
O
^
I
£
CO
90
80
70
0 60
.S 50
40
30
100
Figure 3.3.3-8.
2 5 |000
Frequency in Hz
Power Plant Location 7
10000
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. LOQ, L.50/ and L^Q Percentile Values were obtained from 100
Samples with One Second Integration Time.
Daytime
Nighttime
-124-
-------
IO
I
O eo
tO "O
o
t3
0
60
50
40
30
100
Figure 3.3.3-9.
2 5 |000
Frequency in Hz
Power Plant Location 8
10000
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. LOQ/ LSQ, and L,Q Percentile Values were Obtained from TOO
Samples with One Second Integration Time.
Daytime
Nighttime
-125-
-------
CN
2!
ca
TJ
JC
1
Number of Occurrences
Daytime
2
ca
~°
c
"«
1
0)
o
55
56
57
58 *
59 **!
60 **
61 **
62 **
63 **.
TJ O«i
^ 65
*********
**************
***********
*************
Number of Occurrences
Nighttime
Figure 3.3.3-10. Power Plant Location 1.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-126-
-------
40
E
o
$
co
-o
c
••—
1
.3
o
10
_E
.5?
"5
42
43
44 **
45 *
46
47
48
49 *
50
51
52 ***
53 ************
54 ***********
55 ***********
56 ****
57 *
58 **
59 *
60
61
62 *
63
64
65
Number of Occurrences
Daytime
£
CQ
-o
1
55
56
57
5g ****
*******************
59
60
61
*********
******
.2?
*»
62 **********
63 *
64 *
65
Number of Occurrences
Nighttime
Figure 3.3.3-11. Power Plant Location 2.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-127-
-------
I
£
co
c
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
*********
****************
********
*
**
***
**
*
****
*
*
64
'& 65
Z 66
"S 67
-£ 68
O)
•f 69
5: 70
**
************
************
************
*
*****
***
*
Number of Occurrences
Daytime
Number of Occurrences
Nighttime
FJgureS.3.3-12. Power Plant Location 3*
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-128-
-------
CM
0 61
, 55
e 56 *
Z 57 **
i 5g *******
2 59 *
<3 60 *****
******
to 62 **
"° 63 ****
•- 64 ********
1 65 **
jj 66 **
« 67 *
.!! 68 **
•2 69 *
•O
I
2
eo
O>
55
56
57
58
59 ********
60 *************
O 62
•5 63
Z
***********
64 **
65 **
fl> 71 ***
^> 72 **
"S 73 *
< 75
Number of Occurrences
Daytime
Number of Occurrences
Nighttime
Figure 3.3.3-13. Power Plant Location 4.
Noise Level (A-We?ghted) Histogram 50 Samples Four Second
Integration.
-129-
-------
— -
E
2*
o
*x
0>
CO
C
—
-------
CN
>O
55
56
57
58
59
60
61
62
J 63
t 64
o 65
2 66
d 67
2 68
a 69
•0 7n
C 70
- 71
» 72
_» 73
• 74
•5 75
Z 76
-o 77
1 78
.S> 79
® an
> ofe)
5 8i
< 82
83
84
85
**
*******
***
******
***
**
*****
*
******
****
*******
*
*
*
*• 55
£ 56
3 57
c 58
r 59
% 60
3 61
8 62
'o 63
Z 64
"S 65
0)
**
***************
*******************
*******
Number of Occurrences
Daytime
Number of Occurrences
Nighttime
Figure 3.3.3-15. Power Plant Location 6.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-131-
-------
(N
>
Z
o
r*m*
x
-------
•?
0
55
56 **
57
«° 58 **********
c 59 **********
^ 60 ******
£ g} ********
JS 62 *
S 63
f™ 64 ****
65 **
66 *
67
•S 68
I 69
J- 70
Pj
1
O
•— ;
CN
2
co
TJ
C
~
>
0
V
1
•o
±
.5?
"5
i
"^
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
Number of Occurrences
Daytime
**
****
********
************************
**
**
***
**
**
Number of Occurrences
Nighttime
Figure 3.3.3-17. Power Plant Location 8.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-133-
-------
Table 3.3.3-1 -
Intrusive (L1Q) Noise Level (A-Weighted) Observed at
Power Plant Community Locations During Day, Evening,
and Nighttime Sampling Periods
Noise Level dB(A)
Noise Level dB(A)
Location
1
2
3
4
Day
52
51
54
56
57
56
60
59
55
60
58
68
64
57
63
Evening
53
59
58
49
58
52
60
Night
60
62
51
53
66
62
54
57
58
64
51
56
58
64
53
63
64
Location
5
6
7
8
Day Evening
66
69
77
74
70
59
56
65
62
62
58
62
62
63
65
66
Night
58
63
61
53
59
62
58
61
68
59
63
70
58
61
61
60
60
60
58
63
60
58
58
63
-134-
-------
a
I
0
in
V
o
t)
0
I
,= o
0
no
too
90
? 80
CQ
-o
C'
70
60
50
I
31.5
-J—
<9
125
250
.. I
500
100
1000
-J-
2000
1000
4000
—I—
4-
wooo
L_
dB(A)
10000
Figure 3.4.2-1
Frequency in Hz
One-Third Octave Band Sound Pressure
Levels Measured near the Rough Grinding
Operation in an Automobile Assembly
Plant.
-135-
-------
0)
o.
I
1
U
O
"E
0)
6
X
CN
CO
-o
0)
0)
70
60
dB(A)
100
1000
10000
Frequency in Hz
rRtgure 3.4.2-2. One-Third Octave Band Sound Pressure
Levels Measured in the Weld Destruct
(Chipping Operation) Room in an Auto-
mobile Assembly Plant.
-136-
-------
110
100
•*NE
8 >
90
,
m
>
u
o
TJ
^mm
_C
4)
c
0
80
0)
CQ
TJ
•5 70
v
601
50
31.5 63 125
250
5OO
1000
eooo
4000
•000
WOOD
5 100
Figure 3.4.2-3.
1000
Frequency in Hz
To ooo
One-Third Octave Band Sound Pressure
Levels Measured near the Piercing and
Hole Cutting Operation in an Automobile
Assembly Plant.
-137-
-------
y,
I
•?
JU
z^
.
o
no
100
90
o
CO
0>
O -5
-O -2
6
80
70
60
50
, dB(A)
31.5
I
63
I
125
_J
250
I
500
I
1000
2000
I
4000
•000
WOOD
I
100
Figure 3.4.2-4.
s 1000 z a
Frequency in Hz
One-Third Octave Band Sound Pressure
Levels Measured near a Forced Draft
Air Blower in an Automobile Assembly
Plant.
10000
-138-
-------
3 "^.
in
1 '<=
* a
0
I
x
«
6
CQ
-o
c
no
90
80
70
60
50
dB(A)
31.5
,1
63
125
290
I
100
500
-4-
1000
1000
2000
—I—
4000
—4—
wooo
4-
10000
Frequency in Hz
Figure 3.4.2-5. One-Third Octave Band Sound Pressure
Levels Measured near Two Reciprocating
Compressors in an Automobile Assembly
Plant.
-139-
-------
6
no
100
90
80
70
60
50
<' dB(A)
31.5
I
63
I
125
_J
250
I
500
1000
tooo
4000
•000
WOOD
100
Figure 3.4.2-6.
z s 1000 z »
Frequency in Hz
One-Third Octave Band Sound Pressure
Levels Measured near A Typical Air
Blowing Operation an an Automobile
Assembly Plant.
10000
-140-
-------
ffl
1
£
0
in
0
eo
0
I
u
0
0
6
m
'o
0)
OQ
T 70
0)
1
60
50
100
Figure 3.4.2-7.
Frequency in Hz
One-Third Octave Band Sound Pressure
Levels Measured near Paint Pots' Air
Blow-Off Operation in an Automobile
Assembly Plant.
-141-
-------
2
I/I
18
1 N
o
to
I
U
O
no
100
90
80
2
CN
CQ
-C ~Z
0
a>
6
70
60
50
< dB(A)
318
•a
i
its
600
1000
1000
I
nooo
i
100
1000
Frequency In Hz
10000
Figure 3.4.2-8. One-Third Octave Band Sound Pressure
Levels Measured Below A Roof-Mounted
Exhaust Blower in an Automobile Assembly
Plant.
-142-
-------
110
0.
1
o
-------
no
0)
•8NE
.1 2T
•o
o
CO
V
I
o
O
0)
6
i
CQ
Q>
o>
100
90
80
70
60
50
/
I
Vs
8 •
1
X,
1 II
y\
' \/
6 tl
j
/
s/
0 K
1 . . 1
\/
0 I0<
-X
» 10
1 1
X
/
00 40
1 1
^
oo to
/
N WC
00
. dB(A)
)
i
i
Frequency In Hz
Figure 3.4.2-10. One-Third Octave Band Sound Pressure
Levels Measured During an Engine Drop
Operation (Pneumatic Impact Wrenches)
in an Automobile Assembly Plant.
-144-
-------
£
I
0
T
•••
X
i
0
CO
-o
c
lOf
90
80
70
60
50
/
•
V.^^x
IB 1
\
X
» II
A
' ^
IB 1
/
\/
10 Bl
/^-
10 10
^
oo 10
-/
«0 40
1
^_
00 M
/
00 W(
1
«0
i dB(A)
I ' » JOO > » 1000 * • 10000 »
Figure 3.4.2-11
Frequency In Hz
One-Third Octave Band Sound Pressure
Levels Measured During Engine Drop
Operation (Pneumatic Hoist) in an
Automobile Assembly Plant.
-145-
-------
-g 'o
3 X
u
O
6
CQ
TJ
C
0>
0)
no
100
90
80
70
60
50
dB(A)
31.5
•3
I
125
I
250
I
SOO
[
1000
I
2000
4OOO
•000
WOOD
100
1000
10000
Frequency in Hz
Figure 3.4.2-12. One-Third Octave Band Sound Pressure
Levels Measured near a Metal Finishing
Operation in an Autombile Assembly
Plant.
-146-
-------
Feet
Weekend
Weekday
Weeknight
Weekend
Weekday
Weeknight
Key
I I I I I
Community Noise Levels in dB(A)
1 23456789
47 43 49 45 43 47 45 48 47
50 48 50 49 47 54 50 53 50
51 50 50 50 47 52 48 54 48
Plant Property Line Noise Levels in dB(A)
abcdefghi f
54 47 46 46 47 54 54 49 54 46
58 57 55 53 54 62 57 54 55 54
57 57 56 51 53 58 55 53 54 54
Industrial Noise Source
Plant Property Line
Residential Area
Railroad Track
Highway
Measurement Location
Figure 3.4.3-1
Automobile Assembly Plant Community
-147-
-------
.3
£ CS
I I
CO
5
o
o
£
eo
90
80
70
60
50
40
30
100
10000
2 5 |000
Frequency in Hz
Figure 3.4.3-2. Automobile Assembly Plant Location 1
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. L90, L-n/ and L n Percentile Values were Obtained from TOO
3w I v
Samples with One Second Integration Time.
Daytime
Nighttime
-148-
-------
£
i"i
"g ID
8^5
,—
5
s
u
0
CO
TJ
30
100
10000
1000
Frequency in Hz
Figure 3.4.3-3. Automobile Assembly Plant Location 2
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. LOQ, LCQ, and L.Q Percentile Values were Obtained from 100
Samples with One Second Integration Time.
Daytime
Nighttime
-149-
-------
•H
o
O
CQ
~0
100
10000
1000
Frequency in Hz
Figure 3.4.3-4. Automobile Assembly Plant Location 3.
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. L9Q/ L-5Q/ and LJQ Percentile Values were Obtained from 100 Samples
with One Second Integration Time.
Daytime
—— Nighttime
-150-
-------
0
CD
V
1
o
0
o
CD
-o
100
Figure 3.4.3-5.
z s 1000 *
Frequency in Hz
Automobile Assembly Plant Location 4
10000
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. L90/ 1.50, and LJQ Percentile Values were Obtained from 100
with One Second Integration Time.
Daytime
Nighttime
-151-
-------
o
to
O
s
o
o
CO
-o
50
40
30
100
Figure 3.4.3-6.
1000
Frequency in Hz
Automobile Assembly Plant Location 5
10000
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. 19Q, L^Q, and L,~ Percentile Values were Obtained from 100
Samples with One Second Integration Time.
Daytime
Nighttime
-152-
-------
0)
o
2 04
«o
3
0
10
1
£
I
o
0
V
CD
90
80
70
60
50
40
30
3
— '
xx"'
1.5 C
1
^^*
M1MWWMBMMM
,^:
3 1
\
^
X
!S 2
^
^
\J
90 S
fa
m
^J^
"~"-^>
00 10
— L90
™L50
r~Lio
^
v
S^
— — s<-
OO CO
Sri ^^
^
00 40
C^.
00 M
, ,, ,
00 *<
OO
Frequency in Hz
Figure 3.4.3-7. Automobile Assembly Plant Ucatibn 6.
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. 1.90, LSQ, and L|0, "Percentile Values were Obtained from 100 Samples
with One Second Integration Time.
Daytime
— Nighttime
-153-
-------
0)
D.
CO
o
O
I
2
CQ
T3
30
100
10000
z s |000
Frequency in Hz
Figure 3.4.3-8. Automobile Assembly Plant Location 7.
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. LC-Q/ LSQ/ and L|Q Percent!le Values were Obtained from 100 Samples
with One Second Integration Time.
Daytime
— Nighttime
-154-
-------
i
V
5 CM
O
t/>
4)
i
y
0
X
CM
CO
TJ
C
90
80
70
60
50
40
30
100
10000
1000
Frequency in Hz
Figure 3.4.3-9. Automobile Assembly Plant Location 8.
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. 1-90, LSQ, and L|Q Percentile Values were Obtained from 100 Samples
with One Second Integration Time.
. Daytime
Nighttime
-155-
-------
I
o
o
CD
P
O
o
>O
o
A
«
t 60
CO
-o
c
50
40
30
100
Figure 3.4.3-10.
s |000
Frequency in Hz
Automobile Assembly Plant Location 9
10000
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. LQQ, LKQ, and L,Q Percentile Values were Obtained from 100
Samples with One Second Integration Time.
Daytime
Nighttime
-156-
-------
cs
E
£
•>
'o
3
V X
-------
CM
£
ca
T3
Q)
l/»
*O
o>
50
51 *
52 *******
53 ******
54 ********
55 **********
56 ******
57 **
5g ******
59
60
61
62
63 ***
64 *
65
Number of Occurrences
Daytime
CO
TJ
O
50
51
***********************************i
52 ************
53 **
54
55
Number of Occurrences
Nighttime
Figure 3.4.3-12. Automobile Assembly Plant Location 2.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-158-
-------
CM
10
'o
5
CS
tm
CO
"0
c
I
1
"o
I
£
^
^
1
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
»
o
«s
0
CO
"O
_c
"0
.3
"o
z
?
"ob
"o
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
*
**
**
**
**
**
*
*
*
*
**********************
******
**********
Number of Occurrences
Daytime
Number of Occurrences
Nighttime
Figure 3.4.3-13. Automobile Assembly Plant Location 3.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-159-
-------
CM
if)
0)
GO
-o
C
in
*O
-o
50
51
52
53
54
55
56
57
58
59
60
****
**********
*********
***
*
*—^
t
0
A
«-
CO
TJ
c
^_
0
.3
0)
in
"6
Z
~S
3=
O)
in
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
****
****
****
****
*
*
*
Number of Occurrences
Daytime
***************************
Number of Occurrences
Nighrtime
Figure 3.4.3-14. Automobile Assembly Plant Location 4.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-160-
-------
CM
IT)
(N
fc.
A
£
tD
-o
C
• •
1
V
o
I
ro
45
46
47
4g ***********
50 ***********
5} *****
52 ***
53 *
54
55
56
57 *
58
59
60
61
62 *
63 *
64
65
Number of Occurrences
Daytime
C$
£
CQ
13
"S
45
46
47
_ 48 *****************************
S| 49 *******************
3 50
o 51 **
5 52
Z 53
54
.£?
'5
55
Number of Occurrences
Nighttime
Figure 3.4.3-15. Automobile Assembly Plant Location 5.
Noise Level (A-Weighted) Histogram 50 .Samples Four Second
Integration.
-161-
-------
,1
o
CN
2
CO
T3
C
12
>
1
1
50
51
52
53
5A
55
56
57
58
59
60
61
62
63
6A
65
*
******
****
**
***
********
********
*****
***
***
****
***
CM
-o
jc
J
o
JE?
?
50
51
52 ****
53 ************
54 **********
55 **
56
57 ***
59
60
61
62
63 ****
64 **
65 **
66
67
68
69
70
Number of Occurrences
Daytime
Number of Occurrences
Nighttime
Figure 3.4.3-16. Automobile Assembly Plant Location 6.
Noise Level (A-Weighfed) Histogram 50 Samples Four Second
Integration.
-162-
-------
CM
CD
•o
1
o
I
2
S
"5
51
52
53
54 ***
55 ******
56 ********
57 *********
58 ********
59 ************
60 ***
61 *
62
63
64
65
Number of Occurrences
Daytime
CO
TJ
I
s
45
46
47 ******************
48 ******************
49 ************
50
51 **
52
53
54
55
Number of Occurrences
Nighttime
Figure 3.4.3-17. Automobile Assembly Plant Location 7.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-163-
-------
«o
00
T3
C
O
o
Z
1
<
50
52
53
54
55
56
57
58
59
60
61
62
63
64
65
:; ********
****************
***
*******
**
***
**
Number of Occurrences
Daytime
1
n
?0
A
£
CQ
TJ
C
Muni
SJ
.3
0)
«O
"6
Z
1
_c
.5*
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
********************
*********
*********
***
Number of Occurrences
Nighttime
Figure 3.4.3-18. Automobile Assembly Plant Location's.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-164-
-------
'E
o
'o
&
u
eo
TJ
£
1
JS
M
'6
•o
4»
13
$:
^1
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
in
'o
"x
£
co
"O
£
—
1
8>
'o
Jc
'3
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
*****************
****
*
*
*
****
*
**
Number of Occurrences
Daytime
Number of Occurrences
Nighttime
Figure 3.4.3-19., Automobile Assembly Plant Location 9.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-165-
-------
Table 3.4.3-1 - Intrusive (L10) Noise Level (A-Weighted) Observed at
Automobile Assembly Plant Community Locations During
Day, Evening, and Nighttime Sampling Periods
Noise Level dB(A)
Location Day Evening Night
1
Noise Level dB(A)
Location Day Evening Night
55
55
52
59
55
56
32
69
64
56
57
54
58
53
55
52
54
55
58
54
55
64
54
58
56
52
52
52
54
56
56
49
52
57
52
54
56
57
52
50
53
59
52
50
50
49
8
64
64
65
58
60
51
57
56
54
62
64
62
59
58
57
52
62
58
49
53
54
63
49
49
55
59
59
58
58
48
54
-166-
-------
ID
0
c
0
CQ
0)
O
O
0
CO
TJ
C
1, dB(A)
60
too
Figure 3.5.2-1.
Frequency in Hz
Octave Band Sound Pressure Levels
Measured at the Air Compressor
Section in a Can Manufacturing
Plant.
-167-
-------
120,
110
in
0>
l! "' 100
1 N>E
§ 2T
a. u->
"i ^ 90
^^ ^v ' *
O CN
-a *
| .£ 80
tJ
O
70
60
i
3
^
.5 6
/
3 1!
^^.^
!5 2!
•
M> 9C
"^-^
X) l»
^-^
00 £O
^^^ 1
00 4O
\
\
M m
i 5 |OO 2 5 1000 Z 5 1
00 WO
1
i
00
0000 z
Figure 3.5.2-2.
Frequency in Hz
Octave Band Sound Pressure Levels
Measured near a Ring Pull Punch
Press in a Can Manufacturing Plant.
-168-
-------
120
110
D
0>
-0,0
3
0
0
CO
0
t>
0
X
CM
1)
CO
100
90
80
dB(A)
70
60
31.5
63
125
250
I
5OO
100
1000
1000
2000
4OOO
—I—
•000
10000
WOOD
Figure 3.5.2-3.
Frequency in Hz
Octave Band Sound Pressure Levels
Measured near the Internal Lacquer
Spray Line in a Can Manufacturing
Plant.
-169-
-------
JS ^
58
£ »o
-------
s
S«B
II
f°
'8 A
1 2
;> 9
120
110
100
90
80
70
60
31.5
125
250
5OO
IOOO 200O 4OOO 8000
WOOD
L_
dB(A)
s 100 2 5 IOOO 2 s
Frequency in Hz
Figure 3.5.2-5. Octave Band Sound Pressure Levels of
F longer Line in a Can Manufacturing
Plant.
10 000 2
-171-
-------
H20
0)
CS
I
-o •?
3 ?
40 c5
"S £
t> -••
ca to
o ^
> c
o —
3
100
90
80
70
60
• dB(A)
31.5
I
125
250
500
I
IOOO
ZOOO
I
4000
WOOD
100
s IOOO
Frequency in Hz
10 000
Figure 3.5.2-6. Octave Band Sound Pressure Levels of
a Beader Line in a Can Ma nufacturing
Plant.
-172-
-------
£
3 M
i E
I *
I"o
o •::
w ^J
1 2
to ca
o "°
1 "
o
120
no
TOO
90
80
70
60
,, dB(A)
31.9
,1
63
125
250
I
500
100
1000
-I-
2OOO
4OOO
1000
MOO
-I-
wooo
L_
10000
Frequency in Hz
Figure 3.5.2-7. Octave Band Sound Pressure Levels of an
Air Test Line in a Can Manufacturing
Plant.
-173-
-------
0)
Ji
I
I CM
I
o
to
TJ
O
CO
5
u
O
2
ca
"O
c
120
no
TOO
90
80
70
60
31.5
I
69
I
125
I
250
I
500
I
1000
2000
4000
eooo
100
1000
4-
16000
I
dB(A;
10000
Frequency in Hz
Figure 3.5.2-8. Octave Band Sound Pressure Levels of a
Double Seamer Line in a Can Manufacturing
Plant.
-174-
-------
5
(A * ~
If
1-7
§ 2
TJ
0
£
i
CQ
TJ
C
120
110
100
90
80
70
60
3
1.5 6
/
3 li
Z5 2.
^^x^
SO 5<
X) 10
oo to
00 40
2 ' ' 9 ibo 2 * lobo *
00 80
oo w<
1
JOO
1
, dB(A)
s 10000 *
Frequency in Hz
Figure 3.5.2-9. Octave Band Sound Pressure Levels of a
Minster Ring Pull Press (Near Operator)
in a Can Manufacturing Plant.
-175-
-------
0
£
- CN
flj ^^^^
H
"i £
.2 £2
U
O
120
110
100
90
80
70
60
31.5
I
• dB(Ai
S3
I
125
_J
290
I
500
I
1000
ZOOO
4000
•000 WOOD
100
1000
10000
Frequency in Hz
Figure 3.5.2-10. Octave Band Sound Pressure Levels of a
Punch Press (720 Strokes/Minute) in a
Can Manufacturing Plant.
-176-
-------
§
0 t-
10 »>S
•g •
n fc-
0)
I
o
0
CO
"0
120
no
100
90
80
70
60
\
n dj
31.5
.1
63
125
250
I
500
too
1000
eooo
1000
4000
—I—
•000
10000
WOOD
_L
Frequency in Hz
Figure 3.5.2-11. Octave Band Sound Pressure Levels of a
Body Maker in a Can Manufacturing Plant.
-177-
-------
J-w * > >» A
« V4^O»'\>/
,X. cXX \xx
K <-^\VxX
^N. 'N.^--', *•. VV'»«\>--.V '' .MPx X^ yN«fc
Scale
6 500 KWO I5OO 20OO
Feet
Weekend
Weekday
Weeknighf
Weekend
Weekday
Weekn'ight
Key
Community Noisr:' levels In dB(A)
I 2 3 4 5 :. 7 8 9 10
55 49 53 51 50 50 57 56 51 SB
53 49 55 49 51 54 59 56 56 5->
43 49 53 51 47 49 58 50 55 47
Plant Property Line Noise Levels in dB(A)
abed, efgh? j
58 59 59 61 58 58 52 50 49 53
60 65 64 65 60 60 56 52 57 63
53 63 63 61 58 62 53 43 53 66
Industrial Noise Source
Resident Fa! Area
Railroad Track
Highway
Measurement Location
Figure
Can Manufacturing Plant Community
-178-
-------
0)
-------
CN
o
TO
I
O
t3
O
CM
2
OQ
-o
40
30
100
s 1000
Frequency in Hz
10000
Figure 3.5.3-3. Can Manufacturing Plant Location 2.
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. L9Q/ LJQ, and L|Q Percent!le Values were Obtained from 100 Samples
with One Second Integration Time.
——— Daytime
_ Nighttime
-180-
-------
0)
1
~o *-
C "O
r?
-0 CN
_
5
o
•o
CQ
60
50
40
30
100
Figure 3.5.3-4.
1000
Frequency in Hz
Can Manufacturing Plant Location 3
10000
Community Statistical Noise Spectra Obtained from Djgytime and
Nighttime Surveys. LOQ, ICQ, and L,Q Percentile Values were
Obtained from 100 Samples with One Second Integration Time.
Daytime
Nighttime
-181-
-------
1
CN
«fc Z
•o
1 'o
8 x
o
1
u
O
eo
•o
c
30
100
Figure 3.5.3-5.
1000
Frequency in Hz
Can Manufacturing Plant Location 4
10000
Community Statistical Noise Spectra Obtained from Daytime and Nightt'me
Surveys. LOQ/T LJQ, L,Q Percentile Values were Obtained from 100 Samples
with One Second Integration Time.
Daytime
Nighttime
-182-
-------
-------
i
£
1'
5 3
•2 .£
o
O
90
80
70
60
50
40
30
100
Figure 3.5.3-7.
1000 z
Frequency in Hz
Can Manufacturing Plant Location 6
10000
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. LyQ, L^Q, LJQ Percent Me Values were Obtained from 100 Samples
with One Second Integration Time.
• Daytime
•- Nighttime
-184-
-------
90
£
"g «o
§ '2
(/I v
"i
I 2
u
0
80
70
60
50
40
30
Figure 3.5.3-8.
Frequency in Hz
Can Manufacturing Plant Location 7
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. LQO/ L_-, and L,« Percentila Values were Obtained from 100 Samples
with One Second Integration Time.
————— Daytime
Nighttime
-185-
-------
J5
0)
»rt
8
-O up
8 °
tO X
D
CQ
0)
00
c
O
40
30
100
10000
2 5 1000 2
Frequency in Hz '
Figure 3.5.3-9. Can Manufacturing Plant Location 8.
Community Statistical Noise Spectra Obtained from Daytime and Nighttime
Surveys. I_9Q/ LCQ/ and L,n Percentile Values were Obtained from 100 Samples
with One Secona Integration Time.
Daytime
Nighttime
-186-
-------
^
8 '
w
^
5
f
*
(5
90
80
70
60
50
40
30
100
10000
1000
Frequency in Hz
Figure 3.5.3-10. Can Manufacturing Plant Location 9
Community Statisical Noise Spectra Obtained from Daytime and Nighttime
Surveys. UQ, L5QI and L Percent!le Values were Obtained from 100
Samples. With One Second Integration Time.
• Daytime
Nighttime
-187-
-------
-------
CN
I
-------
®
CO
•o
-------
E
2
co 55
-56
~ 57 ****
fl> 58 **********
« 59
CM
o
60
61
62
63
64
65
********
*****
*
***
0)
Number of Occurrences
Daytime
E
o
A
2
CO
"°
c
"w
J}
J2
o
I
f
.5"
"S
T
•^
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
*********
****************************
***£
**
*
Number of Occurrences
Nighttime
Figure 3.5.3-14. Can Manufacturing Plant Location 3.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
integration.
-192-
-------
M
I
I
«
'o
A
£
CO
•o
c
"3
I
8
I
1
45
46
47
48 *
49
50
51
52
53
54 *
55
56
57 *****
58 ****
59 *****
60 ****
61 *****
62 *
63 **
64 ****
65
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50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
*
*
*
*
*
*
*
*
*******************************
**********
Number of Occurrences
Daytime
Number of Occurrences
Nighttime
Figure 3.5.3-15. Can Manufacturing Plant Location 4.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-193-
-------
2 55 *********
j*, 56 *****
o 57 *********
^ 58 ****
~o 59 ****
.£ 60 *****
U 61 **
« 62 *
~o> 63
.2 64 ***
4 65 **
T, 66
£ 67 *
"ro 68 **
^ 69 *
^ 70
of Occurrences
Daytime
X
0)
GO
45
46
47
48
49
50
51
52
53
54
55
*******************
******
**
*
Number of Occurrences
Nighttime
Figure 3.5.3-16. Can Manufacturing Plant Location 5.
Noise Level (A-Weighted) Histogram 50 Scmples Four Second
Integration.
-194-
-------
CM
50
51
52
g 53
> 54
Z 55
o 56
"x 57
** 58
2 59
3 60
c 61
I 62
5 63
JS 64
« 65
'5 66
Z 67
"8 68
5 69
•5 70
£ 71
i 72
73
74
75
**
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£
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-------
f
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(A
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0>
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
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55
56
57
58
59
60
61
62
63
64
65
**
**
**
**
*
*
Number of Occurrences
Daytime
*********************************
Number of Occurrences
Nighttime
Figure 3.5.3-18. Can Manufacturing Plant Location 7.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-196-
-------
CN
fc«
CO
-a
JC
"3
.2
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.2
f\
z
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*2
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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
*****************
************
**
*********
****
*
*
*
*
*
*
Number of Occurrences
Daytime
Number of Occurrences
Nighttime
Figure 3.5.3-19. Can Manufacturing Plant Location 8.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-197-
-------
CN
—
I
o
A
2
03
c
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1
J3
0)
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Z
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55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
******
**************
****
*****
*****
***
**
*
*
*
***
**
*
c$ 55
Number of Occurrences
Daytime
OQ
I
S
*o
a>
1
56 *******************************************
57 ***
58
59
60
61
62
63
64
65
Number* of Occurrences
Nighttime
Figure 3.5.3-20. Can Manufacturing Plant Location 9.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-198-
-------
E
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0
"x
pj
0}
L.
CO
•o
C
_
0)
1
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M
1
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^
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
**
****
****
****
**
**
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****
***
**
*
****
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O
A
£
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0)
45
46 *******
47 *************
48 *******
49 ****
50 **
51 **
52 ****
53 *
54 **
55 **
56 ***
57 *
58 **
59
60
Number of Occurrences
Daytime
Number of Occurrences
Nighttime
Figure 3.5.3-21. Can Manufacturing Plant Location 10.
Noise Level (A-Weighted) Histogram 50 Samples Four Second
Integration.
-199-
-------
Table 3.5.3-1 - Intrusive (L10) Noise Level (A-Weighted) Observed at Can
Manufacturing Plant Community Locations During Day,
Evening, and Nighttime Sampling Periods
Noise Level dB(A)
Noise Level dB(A)
Location
1
2
3
4
5
Day Evening
54
57
58
63
54
57
66
48
60
57
62
62
54
53
63
58
56
63
63
65
Night
49
52
53
61
60
53
63
58
60
53
54
54
53
51
52
52
49
50
57
Location Day Evening
6 65
66
67
70
7 60
64
63
66
8 55 62
60
61
67
9 67 64
64
66
66
10 67
67
69
66
Night
62
58
65
53
59
57
61
61
53
49
53
56
56
58
56
56
65
68
-201-
-------
4. IMPACT OF PLANT NOISE SOURCES
4.1 On the Work Environment
The impact of the major noise sources of a typical glass
manufacturing plant combines with the impact due to heat
to yield a rather uncomfortable work environment. The
major sources of noise are the I.S. machines which are
similar to blow molding machines. Noise levels A-weighted
at operator positions at these machines range from 99 to
103 dB. Besides high damage risk to hearing, Preferred
Frequency Speech Interference Levels (PSIL) are sufficiently
high so that conversations between foremen and workers are
exceedingly difficult.
At stations where the glassware is inspected by employees,
the noise levels A-weighted range from 87 to 96 dB. These
excessive noise levels are known to provide high damage risk
to hearing and reduce the effectiveness of the inspection
process.
The impact of the major noise sources on the work environment
at an oil refinery is minimal. The furnaces, compressors,
and cracking units are operated remotely. During periodic
inspections, personnel are required to wear ear protection
-202-
-------
devices in high noise areas. These devices take the
form of ear plugs or ear muffs and do not hamper the
employee's work in any manner.
The impact of the major noise sources on the work environ-
ment at a power plant is minimal. Furnaces, gas turbine
and steam turbo-generators, switching stations, and trans-
formers are operated remotely. During periodic inspections,
personnel are required to wear ear protection devices in
high noise areas. These devices take the form of ear plugs,
ear muffs, and hard hat-ear muffs which do not hamper
employee's work in any manner.
Noise source impact upon the work environment at the typical
automotive assembly plant varies from "minimal" to "consider-
able." The noise levels A-weighted at many locations within
the plant have been reduced to below 90 dB. At locations
such as the rough grind booth where this reduction could
not be accomplished, ear protective devices in the form
of ear muffs are required. The ear muffs in combination
with protective clothing cause discomfort, particularly
during the summer months.
At other locations throughout the plant, e.g., metal finishing,
manual air blow-off, pneumatic tool assembly, etc., the
-203-
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Preferred Frequency Speech Interference Level is quite
high, making communication between foremen- and workers
quite difficult.
The impact of noise upon the work environment of the can
manufacturing plant visited is very serious. The plant
employs approximately 1000 hourly workers on a three-shift
basis. A significant number of hearing compensation legal
actions prompted management to institute a mandatory hearing
conservation program in August of 1971. The company provides
molded ear plugs to each plant employee with one or more
years of service. Shorter term employees or those not yet
fitted with the molded ear plugs are required to wear ear
muffs. During a recent inspection, it was observed that
approximately 80 percent of the employees were using the
ear protection devices.
The metal cutting and forming machines are very noisy.
Presses used for installation of "ring pulls" produce a
noise level A-weighted of 104 dB. Air compressor units
are located in the middle of the production area and are
not separated from the work environment by any acoustical
barrier. The noise level A-weighted at this location is 99 dB.
At an employee "rest" area the noise level A-weighted is 98 dB.
Communication throughout the plant is difficult due to the
high Speech Interference Levels.
-204-
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4.2 On the Community Environment
4.2.1 Magnitude of the Impact
Statistical Abstracts of the United States published by the
Bureau of Census for the year 1967, reported that the total
number of industrial establishments in the United States
was 311,000, employing approximately 14,356,000 workers in
production. It is well known that many types of industries
make noise, and that some members of the nearby community
object to this noise while other neighbors do not. This
case study indicates that the community noise is often due
to the combined effects of surface transportation, construc-
tion activity, and the plant. Even for the case where plant
noise is the only source or the predominant source, the
number of persons subject to the noise is small.
For a plant located in a suburban area, the number of adjacent
neighbors may be no more than 100 to 300 persons. The urban
plant may have a greater number of neighbors, but the noise
of the plant is often masked by highways, heavily travelled
streets, construction, or airports. If we conservatively
estimate that the average number of persons subjected to
plant noise is 500 persons per plant and make the obviously
-205-
-------
incorrect assumption that each of the 311,000 industrial
plants in the United States is 'the predominant community
noise source, then about 16,000,000 persons are affected,
which is less than 10 percent of the population of the
United States.
4.2.2 Behavioral Response
A review of the data resulting from the case studies shows
that although interior plant noise levels due to individual
machines, equipment, or processes are exceedingly high, the
impact of the plants on the communities as indicated by the
community complaint histories, is not as high as might
normally be anticipated. High plant noise levels of some of
the plants of this study are reduced by plant building con-
struction or the distance of the plant to the community. Often
the plant noise combines with the other sources mentioned above
to create the total community climate. It should be noted
that each of the five plants in this study is located in
areas where the residual noise levels are relatively high.
When the community noise levels (A-weighted) are compared
with levels shown in the Wyle Contractors' Report, NTID 300.3,
the communities adjacent to each plant may be categorized as
follows:
-206-
-------
• Glass Manufacturing Plant - Quiet suburban residential
to normal suburban residential.
• Oil Refinery - Urbamresidential to noisy urban
residential.
• Power Plant - Urban residential to noisy urban
residential.
• Automobile Assembly Plant - Urban residential.
• Can Manufacturing Plant - Urban residential to very
noisy urban residential.
It is evident that the specific plants of this case study
have no great impact upon the communities. One exception
is the glass manufacturing plant, where the noise levels
exceeded the nearby community levels by nine to 15 dB(A).
This higher noise level was also evident at night. One
family is exceedingly disturbed. Other neighbors, no more
than 25 adults, are also disturbed but to a lesser extent.
The tonal qualities of the gas turbine noise reaching the
power plant community during periods of high power demands
generated sporadic complaints.
Complaints as an indicator of community impact must be
used with caution, as it is known that industrial neighbors
may not object to plant noise, even at fairly high levels, if;
-207-
-------
(a) It is continuous,
(b) It does not interfere with speech communication,
(c) It does not include pure tones or impacts,
(d) It does not vary rapidly,
(e) It does not interfere "with getting to sleep, and
(f) It does not contain fear-producing elements.
Counterbalancing the above effects, single individuals of
families may be annoyed by an industrial noise that does not
annoy other plant neighbors. This often may be traced to
unusual exposure conditions, or to interpersonal situations
involving plant management.
In the next section a process will be described in some
detail regarding the accommodation which exists between a
plant management and the neighboring community, which begins
during the process of seeking an industrial site within the
community and continues throughout the plant's existence
in the community.
4.2.3 Plant-Community Accommodations
The management of any company, large or small, when planning
to build a plant or to lease a building for the plant goes
through a selection process. This process may, at a minimum,
-208-
-------
consist of the search for an empty building for purchase or
rent. For a major industry, the process involves many weeks,
and possibly many months of research and study. Discussions
with municipal officials, real estate experts, and possibly
security, transportation, and communications experts are
required. The company recognizes that it may not be wanted
in a community if it will emit excessive amounts of particu-
lates, unpleasant odors, or loud and unusual noises.
To assure acceptance or accommodation, company management
examines proposed sites for nearby existing industries that
have already been accepted. Also investigated is the level
of control exercised by municipalities and the state govern-
ment over these emissions. This is a first step in a self-
limiting process. Even the small, one-lathe industries are
not likely to locate any closer to residential neighbors
than is absolutely necessary.
During the company's site location studies, it will have to
consider the general requirements of each municipality in
which land and facilities are available, so that by the time
it starts to discuss its preliminary plans with town officials,
the company can hope to accomplish the approval process in
a reasonable time and begin to build. To accomplish this,
-209-
-------
it must first prepare a preliminary plant site layout, a
proposed set of plans and elevations, and a set of general
specifications involving water, sewerage, and traffic require-
ments which might be added to the community due to the location
of the plant.
Many companies prepare handsome renderings of the building
and detailed presentation brochures in order to present their
case to the municipal officials. Often, an initial pre-
sentation is made unofficially to the mayor and the town
council before formal submissions are made to the zoning
board. Usually the mayor and council can adjudge the
financial advantages and must then examine the possibility
of additional costs to the municipality and the possibility
that the industry might noi really be as desirable as the
presentation they have made would lead the viewer to believe.
The result is that often there is considerable negotiating
before the formal presentation is made. These negotiations
may include the addition of company installed roads, sewers,
parks; wastes-water treatment, and special noise abatement
facilities. Faced with these requirements, the company
management might decide that it is too costly to meet the
municipality's goals, and therefore* may move elsewhere.
-210-
-------
The company management might also anticipate that because
\
of an apparent negative citizen feeling in the town, they
would be much wiser to locate in a more welcoming community.
After approval by the zoning board, and this may take as long
as six months after first discussions withv.the mayor and
councilr the notification of approval goes to the mayor and
council for formal approval by that body. Again, it is usual
for public hearings to be held, although on occasion executive
sessions of the zoning board are followed by executive sessions
of the council. This practice is normally frowned upon by
the general public and the press. In the case where public
hearings are held by the council, if the public felt that the
zoning board had not fully considered their needs and requests,
the public may show up with an attorney and several experts
at the council meetings. The industry on its part may be
prepared to make a full-scale presentation and a rebuttal.
Finally, the council meets in either public or private session
and decides the question. Even then, the public may obtain
an injunction against the construction of the plant, or,
by its show of massive rejection of the company, persuade
the management that it would be wise to seek a site elsewhere.
-211-
-------
Even where approval is obtained, the state labor department
may have to approve the plans. A building inspector checks
the construction as it progresses. At any time up to the
time a certificate of occupancy is issued by the building
i
inspector, the municipal officials may review the situation.
The town council, on the basis that the company has not made
a full disclosure or the actual construction differs in
some major ways from the plans, rendering, or brochure, may
require extensive changes to the plant. In any case, the
municipality has tremendous leverage. The municipal officials
are not just local business men. They usually include
experienced real estate and insurance men, engineers, educators,
and people from all walks of life who have a keen dedication.
Their demands may oft^en be politically inspired, but in
general they have a knowledge of the needs of their fellow
citizens and seek to meet these needs.
Even with the issuance of a certificate of occupancy, the
company's liability for further noise abatement efforts is
/
not over. Often the municipal health officer and the police
still have powers to cite management responsible for producing
loud or unusual noises. The local statutes frequently give
wide powers to the municipal officials and police in dealing
with these violators.
-212-
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To understand this accommodation process better, let us look
at a typical industrial/residential township located in a
suburban/rural region of a northeastern state. This township
has a comprehensive zoning regulation, including performance
code sections for air and noise emissions. Not every zoning
regulation has a noise control performance code, but during
the past 15 years, the attention to noise on the part of board
members and private citizens has been growing. The noise
portion of the regulations includes a table of sound levels
which shall not be exceeded at the property line of the plant.
This' performance zoning regulation was developed by the town-
ship 's planning consultant in close cooperation with the town
council and zoning board. The objective was to set forth
some criteria by which new industries could judge the pollution
control needs of their proposed plants. The regulation also
gives the township officials the yardstick by which to assess
the proposals illustrated by the preliminary drawings and
specifications discussed previously. The zoning regulation
also serves to guide existing industries who may become non-
conforming due to alterations to their existing plants.
During the past 10 years, several industries in the township
have modified their plants in a manner that exposes their
-213-
-------
neighbors to noise levels which are believed excessive.
Several complaints have been made to township officials,
who initiated inspections by a building inspector or health
officer. In each ase, noise levels were measured at the
plant line and in the community. In most cases, the industries
involved were sensitive to their neighbors' problems as sooh
as they found that there clearly was an audible noise attribut-
able to their operation. The speed with which they accomplished
remediation varied in each case. Where speedy remedies were
not available to the industry, operational constraints were
used to minimize the noise exposure in the community. The
township requested that company officials appear before the
town council and report on their progress at suitable intervals.
Citizens attending these meetings could always be counted on
to express their views if they believed that the situation
had not been remedied.
4.2.4 Community Noise Equivalent Level
It is difficult to assess the impact of plant noise on the
community by simply viewing the A-weighted ambient noise levels
at various locations in the community during the work day,
work night, or the weekend (see Figures 1-1 through 1-5).
To better understand the effects of the noise and to obtain
-214-
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some qualitative measure of these effect, various rating
systems have been devised. Two rating systems most commonly
used today are the Composite Noise Rating (CNR) and the Noise
Exposure Forecast (NEF). Both forms require complex com-
putation using the perceived noise level, a quantity calculated
by a procedure developed to assess the noisiness of an air-
craft sound. Our desire was to assess the community noise
using the data which we had available, that is A-weighted
noise levels, both ambient (LgQ) and intrusive (L,Q).
Recently an additional rating system has been introduced
which utilized intrusive (L,n) A"-weighting noise levels rather
than the more complex perceived noise levels. This system
developed by Wyle Laboratories and reported in their Con-
tractors' Report to the Environmental Protection Agency NTID 300.3
is the Community Noise Equivalent Level (CNEL).
To compute the community noise equivalent level, the community
noise recorded on magnetic tape was statistically analyzed
to determine the intrusive (LIQ) A-weighted noise levels.
These noise levels were tabulated for each location for day,
evening, and nighttime periods. These data are weighted
and energy averaged in accordance with the formula equation 1.
-215-
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7
CNEL = 20 Log ( -) \Antilog
n I
+ S lAntilog (ELio/10). + 10 lAntilog (NLiv/10).
1* **
where m3n31 are the number of intrusive noise level values
for day, evening, and nighttime sampling periods, respectively,
PLioj ELiQ3 NE'HQ are intrusive noise levels (A-weighted for
day, evening, and nighttime sampling periods, respectively.
The CNEL values thus computed from A-weighted noise levels at
locations in the communities adjacent to the plant are sum-
marized in Table 4.2.4-1. The CNEL value shown at the bottom
of each column is obtained by energy averaging the CNEL value
for each measurement location. The data obtained from
Location 1 at the oil refinery community was not used since
it was determined that the principal noise source at that
location was a chemical plant and not the refinery.
These community noise equivalent levels must be adjusted for
the season, time of day, background noise level, previous
exposure and community attitude, and pure tone or impluse.
Table 4.4.4-2 summarizes types of corrections and provides
description and the amount of correction to be added.
-216-
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Table 4.2.4-1 - Community Noise Equivalent Levels for Community Locations Adjacent to Typical Industrial Plants
Community Noise Equivalent Level in dB(A)
10
H
•vl
I
(a)
Location
1
2
3
4
5
6
7
8
9
10
11
12
13
Energy Average
Glass Manufacturing
68.0
69.4
55.1
51.6
54.0
59.6
52.4
51.3
54.8
61.1
60.3
62.2
53.8
62.2
Oil Refinery
_
65.3
61.4
67.4
62.7
70.9
69.1
59.0
66.7
-
-
-
?•
66.8
Power Plant
65.5
68.3
66.2
69.6
71.8
73.5
68.2
69.0
-
—
-
-
-
69.8
Automobile Assembly
62.6
60.9
65.1
62.3
65.1
66.2
60.5
66.6
62.8
-
-
-
-
64.1
Can Manufacturing
64.0
67.3
64.3
60.7
63.1
69.8
67 J
63.3
66.6
71.9
-
-
-.
67.2
(a) See Figures l-l through 1-5 for Measurement Locations
-------
'Table 4.2.4-2 - Corrections to be Added to the Measured Community Noise Equivalent Level
(CNEL) to Obtain Normalized CNEL (from Wyle)
Amount of Correction
Type of to be Added to Measured
Correction Description
CNEL in dB(A)
Seasonal
Correction
Time of
Day
Correction
for Back-
ground
Noise
Correction
for Previous
Exposure &
Community
Attitudes
Pure Tone
or Impulse
Summer (Year-around operations)
Winter only (or windows always closed)
Daytime
Eveni ng
Night time
Very quiet suburban or rural community, (remote from
large cities & from Industrial activity and trucking)
Normal suburban community (not located near
industrial activity)
Residential urban community (not immediately adjacent
to heavily traveled roads and industrial areas)
Noisy urban community (near relatively busy roads
or industrial areas)
No prior experience with the intruding noise
Community has had some previous exposure to the intrud-
ing noise but little effort is being made to control the
noise. This correction may also be applied in a situ-
ation where the community has not been exposed to the
noise previously, but the people are aware that bona
fide efforts are being made to control the noise.
Community has had considerable previous exposure to
the intruding noise and the noise maker's relations with
the community are good
This correction can be applied for an
operation of limited duration and under emergency cir-
cumstances; it cannot be applied for an indefinite
period.
No pure tone or impulsive character
Pure tone or impulsive character present
0
-5
0
+5
+10
+10
+5
0
-5
+5
0
-5
-10
0
+5
-218-
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The adjustments applied to the CNEL to obtain a normalized
community noise equivalent level (NCNEL) for communities
adjacent to each plant are summarized in Table 4.2.4-3.
The NCNEL thus obtained is plotted in Figure 4.2.4-1 which
is a presentation of the correlation of the NCNEL with
community response. The community response information was
gathered during the behavioral phase of this study. Also
included in Figure 4.2.4-1 is a mean line computed from
values of normalized community noise exposure levels calculated
for 53 case histories from the literature and the files of
Wyle Laboratories and L. S. Goodfriend & Associates. Note
the agreement obtained for data where there is sufficient
noise to cause single threats of legal action or sporadic
complaints. Where the noise is just noticable the data deviates
from the mean. The NCNEL from the automobile assembly plant
community is farthest from the mean. One must ask why, with
the levels of NCNEL so great for the automobile assembly plant
community, sporadic complaints weren't generated? This
deviation from the mean line further reinforces our earliest
contention that complaints may not be a good indicator of
community impact, since it is known that industrial neighbors
may not object to plant noise even at fairly high levels.
Since the mean line was constructed for only 55 case histories
to which we might add five more from this study, the results
-219-
-------
Table 4.2.4-3 - Adjustments Applied to CNEL to Obtain NCNEL for Communities Adjacent to Each Plant
(a)
I
to
to
o
I
Pure Tone/
Plant
Glass Manufacturing
(b)
Oil Refinery
(c)
Power Plant
Automobile Assembly
Can Manufacturing
CNEL
62.2
66.8
69.8
64.1
67.2
Season
0
0
0
0
0
Attitude
0
-5
-5
-5
c
Duration
0
0
0
0
0
Background
+5
-5
™o
0
-5
Impulse
0
0
0
0
0
NCNEL
67.2
56.8
59.8
59.1
57.2
(a) Obtained by Energy Averaging CNEL for Each Measurement Location
(b) Location Number 1 Holt Considered Due to Chemical Plant Noise
(c) Gas Turbine Not Operating
-------
N>
IO
Vigorous Community
Action
Threats of Legal
Action
Widespread Complaints
or Single Threats of
Legal Action
Sporadic Complaints
Noise is Noticeable
50~"
Legend
4 Glass Manufacturing Plant
a Oil Refinery
• Power Plant
• Automobile Assembly Plant
A Can Manufacturing Plant
-Prom Wyle
75
80
Normalized Community Noise Equivalent Level in dB
Figure 4.2.4-1. Correlation of the Normalized Community Noise Equivalent Level With Community Response.
-------
perhaps are questionable. Further investigation into the
correlation between a rating system such as normalized
community noise equivalent level and community response•
using the complaint history as a criteria is suggested.
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5. ATTITUDES TOWARDS NOISE LEGISLATION
5.1 Of the Industrial Plant
For the five industrial plants visited:
(a)'Power Plant,
(b) Can Manufacturing Plant,
(c) Automobile Assembly Plant,
(d) Glass Manufacturing Plant, and
(e) Oil Refinery,
management awareness of current Federal, state, and local
i
\
government noise regulations ranges from "barely aware" to
"fully cognizant." Their information regarding noise
legislation comes from other than plant personnel, such as
insurance companies and the corporate engineering and industrial
hygiene departments. The exception is the oil refinery, which
has an in-plant industrial hygienist..-
The general attitude toward noise legislation, determined
from discussions with plant management, is a good one. With
one exception, management realizes the advantages accrued by
noise abatement in both their employee and their community
relationships. The can manufacturing plant management finds
the Federal Occupational Safety and Health Act of 1970
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objectionable. In lieu of application of engineering
noise control as the Act requires, they have provided all
plant personnel with fitted ear protectors.
The industrial plants which are part of large corporations
(automobile assembly plant and oil refinery), have received
authorization from corporate management to proceed with
engineering noise control, indicating a healthy attitude
toward noise legislation at upper management levels.
The power plant, a part of a state-wide power company, receives
engineering support from a centralized corporate facility.
Staff members providing this support are aware of the benefits
of the current noise legislation and support it fully.
Management attitudes towards noise abatement in general and
the legislation in particular must be good, for they have
been authorizing noise abatement efforts for the past 20 years.
This authorization includes hiring of qualified personnel and
purchase of noise measuring and analysis equipment.
The glass manufacturing plant management and corporate
management have only recently been made aware of their noise
problem. Their attitude is confused. To assist them in
forming an intelligent engineering noise control and hearing
conservation program, they have retained an acoustical
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consulting firm which has recently completed a comprehensive
noise survey and is now planning the second phase of the
program.
5.2 Of the Community
Although noise is recognized as an environmental factor by
each of the five municipalities in which the typical plants
considered in this study were located, it appears that it
occupies a low priority position with respect to community
requests for regulations, or for regulations initiated by
the municipalities. While one municipality has been conducting
noise surveys in industrial plants and may prepare a new
nuisance-type regulation if required, others have no plans to
do anything other than enforce their existing nuisance code
or wait for state guidance for the development of new uniform
codes.
Municipal activities concerning noise regulations, it was found,
are the province of either the board of health or the police
department with any unusual matters usually being referred to
a member of the town council or office of the mayor.
Little interest was expressed by any officials contacted
regarding Federal activity in the area of noise control legislation.
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The results of discussions with township officials, such as
town councilmen, city clerks, board of health officials, and
police are summarized in the following paragraphs.
The town in which the glass manufacturing company is located
has a nuisance ordinance covering noise, but has ho specific
noise ordinance. There has been some talk among the town
council regarding the possibility of a noise ordinance, but
no official action is in progress at present. In general
in this town, most complaints have been very unofficial,
consisting of informal discussions with council members by
plant neighbors. Council members feel that they have had
excellent cooperation from local industries, thus precluding
the need for strong legislation.
Information obtained from the city clerk's office of the town
containing the oil refinery indicates that there has been
no record of any city council action regarding noise complaints
for the past 10 years. A noise ordinance passed in October 1969,
contains no noise level requirements, but instead makes unlawful
"...any loud, unnecessary or unusual
noise, or any noise which either annoys,
disturbs, injures, or endangers the
comfort, repose, health, peace of safety
of others..."
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The municipality in which the power plant studies were
located had previously enacted a stringent noise control
regulation, but this had been successfully challenged by
persons accused of violating it. Since then, the State
of New Jersey has been reported to be considering preparation
of a standard form of regulation for use in municipal codes.
In view of the proposed plan by the State of New Jersey to
develop a uniform code, this municipality has suspended further
activity at the local level.
The town containing the automobile assembly plant currently
has general standards and regulations in its sanitary code
concerning noise and nuisances. The department of health
is now studying existing noise regulations of various cities
and townships to be used as a guide by the township committee
in the preparation of a new noise regulation.
A member of the planning board of the city containing the can
manufacturing plant has recently completed a study of noise
ordinances from many towns and cities in their state. This
member reports that most towns and cities are doing little at
the present time to change their noise ordinances. Instead
they are waiting for state government to issue guidelines and
recommendations. The board of health at one time attempted
to set stringent ordinances which were successfully challenged.
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6. NOISE REDUCTION PROGRAMS FOR INDUSTRIAL PLANTS
6.1 Introduction
The noise of an industrial plant, or plant noise plus surface
transportation noise, contributes to the residual noise level
in its community. Industrial noise is a local problem with
each plant presenting individual intrusive characteristics
which may not be comparable on a nationalwide basis. The
plant location, community residual noise levels, and other
sources such as major highways, airports, or construction
activities contribute to the community climate. The case
studies of industrial plant noise/ while only a small per-
centage of the total industrial establishments, indicate
that plant noise may not significantly impact upon the com-
munity. It appears that noise due to construction job sites,
surface transportation, and aircraft exceeds in importance
the contribution of industrial plants to community annoyance.
At some future date, when noise abatement efforts applied to
the above primary sources successfully reduce their levels,
the contribution of industrial plant noise to the community
residual levels will rise in importance. Then the goal of an
industrial plant exterior noise abatement program may be the
elimination of community complaints, although complaints or
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lack of complaints may not be a satisfactory indicator of
the impact of plant noise on its neighbors.
It is anticipated that, in general, industrial plant noise
reaching the community will not increase in the near future,
but may in fact decrease, as noise abatement efforts required
by the Occupational Safety and Health Act of 1970 become
effective. But it must be pointed out that at specific
locations where interior plant noise is reduced by simply
locating the noise sources outdoors, the impact upon the
community may increase.
6.2 Motivation
A number of significant factors which motivate industrial
plant management to institute noise reduction programs will
be discussed.
In the past, the primary motivation was the desire to be good
neighbors and to maintain good community relations. It was
found through discussions with industrial plant management
that the large corporations of national stature are particularly
sensitive to public relations. Funds and personnel are
quickly made available to solve noise problems which the
plants are made aware of by community complaints. Often plant
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management anticipates community reaction in applying local
corrective action to reduce or eliminate the noise problem.
The site selection and industrial plant design processes
together with the local government control of industrial zoning
provide the motiviation and the early opportunity to institute
noise abatement efforts. It is known that this early phase
of industrial plant development provides the most economic
period for application of noise reduction techniques. Local
municipal pressures in the form of noise nuisance ordinance
and, more recently, realistic zoning regulations have produced
legal pressures to reduce plant noise. The zoning ordinance
for the township in which the glass manufacturing plant of
the case study is located, is representative of the type
currently being instituted. This ordinance was revised in
June 1966 and contains the requirements shown in Table 6.2-1.
Table 6.2-1 - Representative Noise Regulations (Zoning Ordinance)
2
Octave Band* Sound Pressure Levels in dB re 20p#/m
Hz Daytime Nighttime
20-75 75 65
75-150 60 50
150-300 54 44
300-600 48 38
600-1200 45 35
1200-2400 42 32
2400-4800 39 29
above 4800 36 26
*Bands are presented as shown in the ordinance
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An additional motiviation to reduce plant noise, alluded to
earlier, is the requirements of the Occupational Safety and
Health Act of 1970. This act forms the legal basis requiring
the initiation of noise reduction programs for in-plant
noise sources. That these in-plant noise sources may be
sufficiently high not only to be hazardous to employee hearing,
but also to contribute to the total industrial plant exterior
noise picture can be seen in Table 1-1.
Consumer pressures, which exist for other sources, are not a
•motivating factor for plant noise reduction. The consumer is
interested in the end product and not in the manufacturing
process producing the product.
6.3 Methods of Approach
The potential for reducing interior and exterior noise of
industrial plants is in general excellent. The engineering
and architectural techniques for reducing this noise along
its transmission paths are known at present. However, reducing
the noise at its source may be difficult and expensive, often
resulting in the degradation in performance of the equipment,
machine, or process.
For new plants, application of noise abatement techniques during
site selection and plant design, together with realistic noise
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level requirements for new equipment being purchased, provide
an economical and effective means for achieving noise level
goals. Many companies are currently developing purchase
specifications which contain noise level requirements. An
example of this is the parent corporation of the automobile
assembly plant discussed in Section 3.4. This corporation,
one of the "big three" automobile manufacturers, requires
suppliers to perform noise studies at the manufacturer's
location under simulated production conditions prior to ship-
ment, to assure compliance with company standards.
An existing plant must achieve noise goals by application of
noise reduction techniques to the acoustical transmission
path, as it generally proves to be difficult and expensive
to reduce the noise at the source. Noise of ventilation and
blower systems which terminate outside a building may be
reduced by application of mufflers, acoustical louvers,
or simple barriers. Often relocation of the intake or exhaust
to take advantage of noise directivity solves the problem.
Furnace noise evident at power plants and oil refineries has
been reduced by redesigned burners combined with mufflers at
the inlet to the fire box.
Noisy areas inside plants have been effectively reduced by
application of mufflers, vibration isolation, acoustical area
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treatment, or enclosures. A systems approach must be
utilized to insure that all the major noise sources are
abated. If one noise source of a group of noise sources
is left untreated, the results of the noise reduction program
may prove to be insignificant.
6.4 Future Commitment
The case studies discussed in Section 3., though representing
only a small portion of the total industrial activity in the
country, illustrate the range of industrial commitment to
noise reduction programs.
Plans for further noise suppression at the glass manufacturing
plant are being developed by their acoustical consultant. Funds
on the order of $12,000.00 have been committed for noise
abatement at this plant, and approximately $50,000.00 per year
has been committed for central corporate noise research.
Noise abatement efforts at the oil refinery and power plant
will be continued at their present levels, with emphasis given
to developing improved equipment purchase specifications. One
•*>
of the "big three" automobile manufacturers, mentioned previously,
has budgeted $2,000.000.00 for noise control efforts in 1971, and
plans to budget approximately $4,300.000.00 in 1972. The can
manufacturing company has no future noise suppression program.
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6.5 Plant Noise Control Programs (Past,Present and Future)
Glass Manufacturing Plant
Essentially no planned noise abatement programs were under-
taken at this plant or by the corporate engineering facility.
Noise control measures were initiated by community complaints.
Due to a community complaint, a cinderblock housing was
placed around their forced air blowers. The inlet to this
housing contains an inlet silencer. Also due to a community
complaint, acoustical louvers were installed at the ground
level exhaust from basement mold cooling fans.
•Community complaints resulted in the township retaining an
acoustical consulting firm. Daytime and nighttime noise
measurements were made at the property line of the plant
and at one location in the community. These data indicated
that the local township noise ordinance was exceeded both
at the property line and in the community. These results
were reported to plant management and an acoustical consulting
firm has been retained. A comprehensive noise survey was
recently completed and the second phase of the effort is
now being planned. Plant management is awaiting the results
of this program for guidance for future noise abatement and
hearing conservation programs.
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Within the past year the corporate research engineering
group has assigned one man to noise control for equipment
being designed for use in the glass manufacturing plant.
The corporate research engineering group will actively
undertake a noise abatement program of about one and one-
half man years per year. One man will be assigned to conduct
noise surveys.
Plant management anticipated that the acoustical consulting
firm they have retained will aid them in planning an effective
hearing conservation and noise control program.
Oil Refinery
A consulting firm was retained in 1951 to perform a noise
survey within and around the refinery. When it was discovered
that excessive noise was being generated by a catalytic
cracking unit stack, a muffler was designed (in-house) and
installed. This effort reduced the noise to a more accept-
able level. This stack was 250 feet high and was a serious
source of noise in the nearby community.
An audiometric examining program was begun for employees
in 1952. Maximum allowable noise levels were prescribed
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for in-plant and property line locations in 1956. These
levels were selected after careful research by the corporate
noise research group. The same year, a noise dosimeter
was developed, again by corporate research, to evaluate
worker exposure to noise.
The company has developed Original Equipment Manufacturer
(OEM) noise level data requirements. As part of sales
proposals, vendors must measure and report equipment noise
levels. In addition, vendors must list permissible exposure
levels (A-weighted and octave band) at the worker's position
relative to the machine or equipment.
Plant noise design criteria have been developed to assist
plant engineers in meeting community noise level requirements
and worker exposure limits.
Noise level .'maps of the plant containing A-weighted and
octave band level data which describe the noise level dis-
tribution around the plant grounds, are maintained and up-
dated at prescribed intervals.
An extensive audiometric examination program is maintained.
All prospective employees are tested before being considered
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for employment. Tests are repeated every two years for
employees under 40 years of age, and annually for employees
over 40 years of age. If the under 40 employee is known
to be exposed to above average amounts of noise, he is
retested annually. Examinations are given to employees
being terminated or those retiring.
A wide variety of hearing protection devices are made
available at the industrial hygiene office. Employees
>
entering high noise areas are expected to use them. Good
cooperation from employees regarding hearing protection
devices has been observed.
A continuing effort at the refinery and corporate research
headquarters is under way to develop and implement as
complete a noise abatement program as is possible. The
corporate research headquarters has assisted the refinery
in 16 to 18 noise control problems in the last few years.
The refinery and corporate research headquarters plan to
continue their .present efforts. Projects are continually
under way to develop new noise control techniques which
apply to a broad range of refinery noise sources. Purchase
specifications are being developed to limit noise levels
of computer peripheral and data processing equipment being
introduced to refinery operations.
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The American Petroleum Institute has retained an acoustical
consulting firm with the objective of developing industry-
wide noise abatement guidelines for:
(a) hearing conservation,
(b) speech interference,
(c) community response,
(d) product noise reduction,
(e) plant design, and
(f) equipment purchase specifications.
Power Plant
The corporation has maintained a central acoustics depart-
ment for at least 20 years. Transformer substations,
gas turbine, and steam generation sites have had noise
surveys conducted prior to the final site selection. After
construction is completed and equipment is operating at
full capacity, noise surveys are repeated.
Due to community complaints in the past, walls, i^e.,
acoustical barriers, have been constructed to obstruct
noise radiating from forced draft blowers, valves, trans-
formers, and switching stations.
No audio-metric testing program for employees was instituted.
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All surveys and noise abatement efforts were accomplished
by the corporate acoustics group. No consultants have been
retained.
Hearing protection devices (ear plugs or muffs), are avail-
able at the power plant. Use of the hearing protection
devices is mandatory at the gas turbine installation. The
power plant has recently acquired a combination "hard hat"
and ear muff.
Three men experienced in field measurements are available
from the corporate acoustics group on an "as needed" basis.
One man is assigned noise projects full-time. Present
projects, in cooperation with manufacturers, deal with
the reduction of noise from machines and equipment, with
special emphasis given to gas turbines and steam and gas-
reducing valves.
Audiometric testing, as part of a comprehensive hearing
conservation program, is being considered for future
implementation.
Equipment purchase specifications will contain a noise
level section. The noise level requirements for equipment
and machinery are under study at present.
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The reduction of valve noise is a high priority future effort.
When accomplished, only quiet valves will be installed at
power plants and a retrofit program will be instituted for
replacement of existing noisy valves.
Automotive Assembly Line Plant
The parent company has been involved in hearing conservation
programs on a national scale. Each component plant, e.g.,
stamping, foundries, automotive assembly, etc., has had
a noise survey by industrial hygiene personnel. Magnetic
tape recordings were made at each noise source and later
analyzed.
In-plant corrections were accomplished by maintenance personnel
if possible, or by consultants specifically retained for
the problem. Reduction of pneumatic tool and hoist noise was
accomplished using makeshift mufflers. A tire drop retainer
noise was reduced by liberal application of automotive undercoai
Noise radiating into the plant from automatic air blow-off
(for removal of dust, lint, etc.) was reduced by the use of
an acoustical enclosure.
If engineering control is not sufficient or possible, then
ear protection is required. A study was conducted in con-
junction with the University of Michigan to evaluate ear
protection devices.
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At the assembly plant, personnel (safety superintendent)
are trained in the use of sound level meters and are
required to monitor all plant locations. Every effort is
made to reduce the noise levels to below 90 dB(A), or
personnel are required to wear ear protection devices.
Corporate industrial hygienists periodically conduct a com-
prehensive noise survey to locate major noise sources and
to reduce them by engineering noise control measures.
Corporate equipment purchase specifications at present,
specify equipment noise levels to be used by assembly plant
purchasing agents.
Wearing of ear protection devices will be mandatory effective
1 September 1971, in all plant areas where studies show noise
exposures are in excess of the Federal Occupational Safety
and Health Act's requirements. When the ear protection
device program is fully implemented on a mandatory basis,
there will be approximately 35,000 ear protectors in use
company-wide.
Noise studies will be performed on machinery under simulated
production conditions at the manufacturer's location to
assure compliance with company standards before being shipped
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to the plants. Manufacturers have been very cooperative
and are eager to install noise controls on their machinery
or tools where required.
Based on engineering projects, plants have increased their
budget allotments for noise control significantly. For example,
almost $2,000,000.00 was budgeted for noise control in 1971.
In 1972 this figure has been set at approximately $4,000,000.00.
Can Manufacturing Plant
No noise abatement effort has been accomplished in the past.
No engineering controls have been established. The company's
insurance carrier in 1970 recommended:
(a) All personnel in areas were 90 dB A-weighted is
exceeded should be provided with ear protection
until engineering controls are established.
(b) The apparatus area, where compressors and similar
noisy machines are located, should be physically
separated from the production area.
(c) Certain large and noisy presses should be acoustically
isolated.
(d) Air exhaust from internal lacquer spray units should
be provided with mufflers.
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(e) A hearing conservation program should be inaugurated.
None of the above recommendations regarding engineering
noise control have been instituted. Instead, a mandatory
ear protection device program was instituted on 2 August 1971.
All production personnel are fitted with molded ear protectors
and are required to wear them at all times on the production
floor. Approximately 80 percent of the employees were using
the ear protectors during an unannounced plant tour.
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7. NOISE ABATEMENT TECHNOLOGICAL ASSESSMENT
7.1 At the Equipment Manufacturers Level
Manufacturers of machinery and equipment that are major
sources of noise within the typical industrial plants visited,
were contacted by telephone or mail regarding their efforts
(past five years, present, and projected five years) in the
area of noise abatement. In addition, they were questioned
as to the noise control equipment or technology not currently
available that they, as manufacturers of noise-producing
equipment, would like to have available.
Obtaining the information described above was difficult.
Many more manufacturers were contacted than are reported
here, due to this difficulty in obtaining technically reliable
information. The results of this technical survey are reported
for manufacturers of:
(a) compressors,
(b) pumps,
(c) furnaces,
(d) air-cooled heat exchangers,
(e) pressure-reducing valves,
(f) I.S. machines,
(g) industrial trucks, and
(h) blowers.
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(a) Compressors
A manufacturer of large compressors (to 40,000 horsepower)
of the type used in oil refineries, describes these units
as being custom-designed and built, none being from
a standard line of compressors. They indicated that
though many customers included maximum noise level
requirements with their purchase specifications, these
noise specifications are given "lip-service." This
manufacturer feels that their units are not too noisy,
at least no noisier than their competitors; therefore,
no appreciable effort is given to noise control. The
have budgeted no effort for developing quiet compressors.
In most installations, they indicate the major source of
noise is due to the piping systems, and they do not
consider this their responsibility. A noise consultant
is part of their staff. His responsibility is to advise
customers of noise abatement techniques, such as mufflers
and pipe lagging, but it is not considered his task to
aid in development of quiet compressors.
This manufacturer expressed the opinion that quieter
compressors could be designed, but that in spite of
purchase specifications containing maximum noise levels,
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must purchasers are not willing to pay the additional
cost of the compressor that designing"for lower noise
levels would entail. When the custom-built compressor
is found to produce noise at levels greater than antici-
pated, the customer is usually willing to relax his noise
limit requirements.
A second compressor manufacturer indicated that this
compressor division contracted with a private acoustical
consultant in the past to specify and recommend methods
to reduce the noise levels for about 30 or 40 non-
standard machines. They have utilized acoustical panelling
and enclosures in order to reduce the noise levels when
required, but they do not modify standard compressors
at the noise source in order to meet their customers'
noise level specifications unless a customer writes a
specific purchase order and is willing to pay for the
research and development in order to accomplish this.
This manufacturer has been forced by tighter acoustical
specifications from their customers to study noise
reduction for their units. There remains a question,
however, whether they can remain competitive with a
quieter product at a higher price.
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Another division of the same manufacturing company,
the centrifugal compressor division, indicates that they
use the following techniques for the design of air
compressors in order to minimize the noise generated:
1. Gears are a major source of noise, therefore,
gears of good quality are essential in order
to reduce the noise level.
2. Direct line seals are used.
3. The compressors are made of cast iron as opposed
to fabricated steel, because this material, has
more inherent damping.
4. The radiating surfaces are minimized, and in the
installation of the compressor, every effort is
made to minimize the piping and/or ductwork.
5. Selection of proper accessories such as gear
pumps, drive motors, etc., is accomplished.
6. Tighter noise level specifications from their
vendors for components of their compressors are
being required.
This division indicates that the parent company has
allocated funds and is sponsoring a research and develop-
ment program by an outside consultant. The purpose of
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the program is to conduct a technological assessment
of the problem and provide recommendations to point
the way for future development of turbo-machinery noise
reduction.
In order to stay competitive, they feel quieter products
must be developed. More people are aware of the problem
of noise, and therefore, a quieter product is a good
selling feature as contrasted with other features that
sold compressors four or five years ago.
The reciprocating compressor division of a third company
has not redesigned any compressors, but has built
enclosures to reduce the noise levels to 85 dB(A).
They also tested several silencers on the air intake
and now provide their customers with silencers or enclosures,
which they sell as options.
A fourth manufacturer indicates that a full-time sound
and vibration consultant is on their staff. Their
research and development laboratory has made major
changes in their entire product line of air compressors.
They have indicated that one of their new products, which
is skid-mounted, does not require a foundation and
generates 50 to 75 percent less noise than conventional
reciprocating or centrifugal compressors.
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(b) Pumps
The first company contacted manufactures a variety of
small-to-medium size pumps. Some pumps are modified
to meet state and local noise ordinance regulations
when complaints occur. During 1970, they spent $20,000.00
to reduce the noise for one line of pumps. The company
is aware of noise pollution problems and regulations,
and they retain an outside consultant when needed.
A second company contacted indicates that they have done
a considerable amount of work with the problem of
structureborne vibration, but not nearly as much for the
airborne noise problem. They have worked on several
design modifications, such as bearings, hydraulics,
couplings, etc., leading towards the optimization of
efficiency and noise reduction.
In the past, a third pump manufacturer's noise abatement
research and development was associated with ultra-quiet
pump operation for application aboard atomic submarines.
At present, they are experiencing a gradual trend towards
tighter noise specifications for special pump operations
in schools and hospitals, rather than for industrial
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applications. The drive system of their pump is the
major source of noise, provided that the pumps are
operated in accordance with company specifications.
This holds true even for large centrifugal pumps and
circulators, as they are normally driven by large electric
motors with forced air cooling, thus generating a great
deal of noise. In addition, the pumps are sometimes
driven by diesel engines which are exceedingly noisy
if not properly muffled. Gas turbines with speed-reducing
gears tend to generate noise at high frequencies. If
the pump is not operated within specifications set forth
by the manufacturer, it can lead to pump cavitation
which creates a great deal of fluidborne noise as well
as mechanical vibration. There is usually a sacrifice in
pump efficiency for a quieter operation, which unfortunately,
most customers are not willing or have no desire to pay for.
Another major manufacturer of large circulating pumps
used in nuclear power plants and also fossil fuel power
plants was contacted. They manufacture a "canned motor
pump" which is sealed in a totally enclosed vessel and
has no shaft seal in the conventional sense. This mahu*
facturer has done a great deal of research and developmeftt
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under government contract to reduce the noise emission
generated by pumps. Various types of approaches taken
(for the canned motor pump), are:
(a) Use of pivoted pad radial bearings in lieu of
sleeve bearings.
(b) Use of multivaned impellers instead of conventionally
designed impellers.'
(c) Use of mufflers on the mdator exhaust to minimize
windage noise.
This company has a full staff in their acoustical research
laboratory. Some of the noise abatement research which
they have accomplished has been financed by outside
industrial and government contracts, while most has been
financed from company overhead expenses.
(c) Furnaces
The company which manufacturers furnaces for oil refineries
has conducted, and is continuing to conduct, research
and development on furnace noise abatement. Research on
the mechanism of combustion noise has resulted in a new
burner design which lowers the sound pressure level by
15 dB. Air inlet mufflers have been developed for these
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furnaces. Using a combination of new burners and inlet
mufflers, they have reduced the sound pressure level of
one particular furnace approximately 15 to 20 dB.
Their mufflers, however, are uniquely designed for each
furnace installation, due to the variation in construction
details from unit to unit.
(d) Air-Cooled Heat Exchangers
A manufacturer of large air-cooled heat exchangers of
the type used in oil refineries indicated that 80 percent
of the purchase requests they now receive have maximum
noise level specifications. Some of these specifications
are more stringent with regard to noise levels at the
operator's location than the Occupational Safety and Health
Act of 1970 requires.
A typical heat exchanger fan has a diameter of 10 to 14
feet, with a tip speed of 12,000 feet per minute. Blade
passage frequency is 20 to 30 Hz, which!is too low a
frequency to be a major problem. Most of the noise due
to this fan is from turbulent air flow interacting with
blades and heat exchanger surfaces, and the vortex shedding
from the blades. The noise level for a typical unit before
noise control efforts have been applied is 91 dB(A).
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Basic noise control techniques which this manufacturer
applies are:
1. Reduction of fan speed and horsepower.
2. Increase of air flow and heat exchanger surface
areas.
3. Sound absorption inside the unit.
4. Damping of panel vibrations and use of a
patented blade tip seal developed to prevent
back flow between the blades and the shroud,
providing better efficiency at the desired low
speeds.
For a given use, the noise can be decreased by increasing
the area of the heat exchanger, thereby decreasing the
air velocity through the unit. The reduction of fan speed
and increase in area causes the fan unit to approach that
of a natural-draft heat exchanger. The degree of quiet
from a particular unit is a function of the price the
customer is willing to pay. In general, the cost of
noise reduction is 1.5 to 2.5 percent of the basic price
of the unit per decibel of noise reduction. A reduction
of 10 decibels below the Occupational Safety and Health
Act of 1970 requirements prices a unit at two to three
times the original cost. Field modifications to achieve
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noise abatement for older heat exchanger units are
exceedingly difficult. This company has been only
able to achieve a three to five dB noise reduction for
these older units.
(e) Pressure-Reducing Valves
The first manufacturer contacted has had an extensive
research and development program in the field of valve
noise abatement for the past three years> and plans to
continue the program in the future. The purpose of this
program is to be able to predict when there will be a
field noise problem, and to have the proper techniques
available to treat it. They have provided a variety
of silencers to their customers. In addition, they have
developed several noise source treatments, such as
"whisper trim," which is a specially designed body trim
that is an accessory to a standard valve.
A second manufacturer of pressure-reducing valves varying
from one-eighth inch to 12 inches in size is well aware
of the noise problem and at the present time is evaluating
their entire product line for future redesign consideraions.
By the end of the year 1971, they hope to be able to market
/'
/
an entire line of redesigned valves which they feel will
be much quieter.
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This company has two engineers who are continually
studying the problem of noise from the installation,
piping, and control aspects, as well as from the re-
design or modification of the valve itself. They
enclose an installation diagram with each valve which,
if followed, provides maximum efficiency and minimum
noise. Occasionally they recommend specific designs
with different accessories such as caps or plugs in
order to reduce the noise or vibration problem still further.
These accessories are provided at no charge, if the customer
is not satisfied. The sales department always consults
with the engineering department when they quote a valve
installation if they feel a noisy installation may result.
Occasionally.some customers do not follow their advice,
constrained by the fact that the proposed installation
may not be economical. This company feels that a quieter
valve is not competitive at a higher price than conven-
tional valves at the present time, mainly due to their
customers unwillingness to spend the extra money. This
is especially true if their purchase order contains no
noise criteria. However, they feel that in the future,
noise will be given greater consideration by the customers
and by industry in general.
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A third manufacturer has conducted an extensive research
and development program on the problem of noise abatement
of pressure-reducing valves. Their sales department
has a mini-computer programmed to predict the sound
\
/
level (within plus or minus five dBO of a valve when
different parameters such as inlet pressure, flow,
pressure differential, diameter, etec., are used as input.
This computer is utilized to help the sales department
recommend to their customers the proper valve and
accessories needed for a quiet installation. Treatment
of noisy valves with pressure reduction ratios of 5 to 1
can be handled easily by means of silencers, but higher
ratios present problems.
They recognize that a major noise problem is the generation
of shock waves as a result of the pressure differential
and velocities in the sonic region on one side of the
valve and subsonic on the other. Silencers do not prevent
the generation of shock waves, therefore they are not
the answer for this type of problem. One theory provides
a rule of thumb that the velocity of the flow through
valve should be limited to one-third of the speed of sound
in order to minimize or prevent the generation of shock
waves. New techniques such as deaerators have recently
been developed.
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(f) I.S. Machines
I.S. machines used by glass manufacturing plants are
often made by a division of the glass manufacturing
company. The manufacturer of a class of I.S. machines
similar to those in the glass manufacturing plant was
contacted and indicated that some funds are allocated
for noise control, but that much of this work is being
done at one of their European plants. They do market
a line of mufflers for these machines, and have made
several design modifications to the basis unit with
noise abatement as the objective. Mufflers have been
developed that reduce spool valve exhaust nois.es on
scoop, baffle, and blow-head mechanisms on two types
of machines. The noise from blow-mold, spool valve, and
blank mold booster cylinder quick exhaust valves on
one class of machines can also be reduced by mufflers.
Noise level reduction of the valve block requires re-
placing the one piece tappet valves and bushings with
two piece valves and bushings that exhaust into an air
chamber at the rear of the valve block. Nylon plates
are used to silence mechanical action of the valve levers,
This newer type valve block has been standard on one
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class of I.S. machines since 1962, and is now standard
on the other. In addition to built-in noise suppression,
this valve block provides savings in compressed air
requirements by reducing air leakage. The design
of the two piece valves and bushings also provides for
increased wearability. Noise suppression equipment
its optional and is easily installed on both types of
machines upon customer request. For older equipment,
mufflers and related parts complete with assembly and
alteration drawings for the I.S. mechanism can be
supplied in kit form at a cost of $75.00 per section
(valve block conversion not included) for both types of
machines. The valve block conversion, sepending on
the vintage of the old valve block and the amount od
modernization required, costs from $285.00 to $890.00
per section. In lieu of converting the old style valve
blocks, new valve blocks can be purchased.
Another manufacturer of I.S. machines similar to the
type used in the glass manufacturing plant, does not
market a line of silencing devices,but indicates that
they are doing research and development to reduce the
noise of their machines. They have a laboratory unit
which they use to test new design modifications. They
also do some noise control consulting for their customers.
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(g) Industrial Trucks
A major manufacturer of industrial trucks was contacted.
They indicated that essentially no noise abatement
efforts were accomplished until about one-and-a-half
years ago. They Occupational Safety and Health Act of
1970 made them aware of noise as a problem. An,industry-
wide (Industrial Truck Association) test procedure was
adopted which required noise measurements to be made
at the operator's ear plus 6, 12, and 18 feet from the
side of the vehicle. These measurements are made at
full speed, maximum load, and no load, plus during a
"drive-by."
Muffling of engines was accomplished by purchasing off-
the-shelf mufflers. Trucks were quieted on a "cut and
try" basis by shrouding the engine compartment. At
present, fan noise is the major source of noise for LP gas
vehicles, while high-speed DC motors are the major source
of noise for electric vehicles. Power-steering pump
noise also is a problem for the electric vehicles,
but the noise of the electric vehicles is well below
the requirements of the Occupational Safety and Health
Act of 1970.
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One-third octave band analysis equipment has been
purchased and is used with the above test procedure
to evaluate the truck noise and to determine noise
sources. Their own industrial trucks and competitive
units are both being tested. They are in the midst
of this program which they anticipate will describe
their problems and help generate future goals. Two
engineers full-time, plus additional help on a part-
time basis, are engaged in this program. The manufacturer
feels that other manufacturers of industrial trucks are
engaged in about the same level of effort.
(h) Blowers
A blower manufacturer contacted indicated that they
sell a fan silencer as an accessory to their industrial
fans, but are not quieting their units. They feel that
there is a future market for a quieter but more expensive
fan. At the present time, the market for quieter fans
is minimal. An increasing trend of concern on the part
K
of their clients with regard to the problem of noise is
indicated.
A second manufacturer of industrial fans, blowers, and
exhaust systems indicated that since they are in the
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small business category, they do not manufacture any
noise reduction accessories; but instead they recommend
that their clients use acoustical consultants.
A third manufacturer of fans, blowers, and exhaust
systems feels that the fundamental noise due to fans
will not be reduced by any significant amount due to
fan design. All their efforts are being directed
to the addition of attenuation through muffling devices
and not to the source studies. They have been reviewing
the research which has been done with regard to noise
for turbines and aircraft propellers, expecting to
adapt some of these developments to fan technology.
In order to meet the Occupational Safety and Health Act
of 1970 requirements in the future, they feel they have
-no choice but to supply the fans as a package with
attenuators and mufflers as part of the system. The
difficulty that they are having with their clients with
regard to th*--. Occupational Safety and Health Act of 1970
requirements is that their customers specify these
requirements, but do not indicate the environment into
which this equipment is going to be installed. This
manufacturer is attempting to educate their clients to
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make them aware of the need for specifying environ-
mental conditions as well as the other performance
parameters of the fan.
7.2 State-of-the-Art Noise Abatement Technology
7.2.1 Introduction
The general approach to noise control in industrial plants
is well established. However, because of the multiplicity
and complexity of industrial plant noise sources and their
associated environment, solutions to industrial noise
problems have been obtained more or less on an empirical
basis. In other words, an analytical solution to every
industrial noise problem does not exist. Experimental
investigations of the noise source should form part of a
noise control development program. Excessive noise in
existing industrial plants can be reduced (to conform to
established criteria for hearing damage, annoyance, or speech
communication) by applying current state-of-the-art noise
abatement technology. However, corrective measures
for existing noisy industrial plants prove to be more
expensive in dollars per decibel of noise reduction than
incorporation of noise abatement features in the original
design of the plant equipment. One of the significant
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advances in noise control technology is the systems approach
concept as applied to noisy industrial machines. The
systems components in such an approach are the noise
sources, the multiplicity of transmission paths, and the
receiver. Noise abatement methods describing the current
state-of-the-art are discussed for the source and
transmission path. The noise abatement approach as applied
to major industrial noise sources, such as gas turbines,
compressors, blowers, etc., is also discussed. One might
conclude that using the present state-of-the-art in noise
abatement, it is possible to control industrial noise and
thus provide satisfactory in-plant and community environments.
One of the more important considerations for industrial plant
planning for noise control lies in the initial design of
new plants and the modernization of existing ones. Archi-
tectural noise control concepts have been successfully
applied to this field for the past two decades. Some general
considerations useful in the engineering control of industrial
noise are enumerated in the following discussion.
For good planning in noise control, it is important to know
the noise characteristics of each machine, process, and
environment. For this to be meaningful, engineering specifi-
cations for the design and selection of equipment or machinery
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should include noise level requirements. Towards this
end, two working groups of the American National Standards
Institute are responsible for the development of basic
acoustic measurement standards applicable to sound radiating
by stationary machinery under field and laboratory conditions
(ANSI Working Groups Sl-W-51 (S3) and S1-W50 (S3)). A list
of standards and specifications for the rating and measure-
ment of machinery noise sources is given in Appendix C.
Further environmental noise levels should conform to the
Federal regulations requiring that the noise characteristics
•of the equipment be known. It is important to know and
compare noise level outputs of equipment, their prices,
and other factors before it is purchased for installation.
The location of the machine inside the plant also involves
several considerations such as the type of noise emitted
(whether intermittent or continuous), how many people other
than the operator will be exposed to noise, whether the
equipment can be enclosed without affecting its operating
efficiency, etc. The location of the equipment within the
plant is an important factor that needs careful study in the
initial planning stages.
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7.2.2 Source Noise Control
Engineering solutions to reduce noise in machinery involve
many different techniques. However, in order to understand
these techniques, it is essential to understand the mechanism
of noise generation. Machinery noise may originate from
one or more of the following important factors: impact,
friction, fluid turbulence, forced vibration, electro-
magnetic effects. The following discussion will be limited
to the noise reduction techniques as applied to the above
factors.
Impact noises are present in most metal fabricating operations
and are proportional to the magnitude of deceleration
at impact, size of the impacting surfaces, mass, stiffness,
and damping2. The reduction in deceleration may often
be achieved by interposing soft elastomeric material between
the hard impacting surfaces. This may iiot be done when the
impact is the desired machine output. Reduction of impact
noise may also be effected by use of a smaller force applied
over a greater period of time, rather than a greater force
for a shorter duration3. Impact noise may also be reduced
by vibration isolation of the driving source and by damping
treatment of resonant machine parts.
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Major sources for noise generated by frictional effects are:
gears, bearings, extrusion presses and sliding linkages.
The usual method of reducing frictional noise is by lubricating
the moving parts, improving the fit (gear or bearing geometry),
and damping.
The noise generated by an air ejection system such as
pneumatic tools, jet engine exhausts, etc., is due to the
high velocity fluid flow of the jet which produces turbulence
when mixed with the ambient air. There are two types of
fluid flow jet systems: one in which the ratio of the up-
stream pressure from the jet nozzle to the ambient pressure
is less than approximately 2:1, and the other in which this
ratio is greater than approximately 2:11*. The noise of the
jet for the first type of flow varies between the 6th and 8th
power of the stream velocity and directly with the area and
density of the fluid5. Therefore, substantial reduction
in the noise levels may be achieved by a reduction in
velocity. The second type of jet is known as choked flow.
In this case, the flow through the nozzle is sonic, but
downstream of the nozzle the flow becomes supersonic,
resulting in shock wave formation. Due to shock wave
formation, the noise generated may be greater than that
calculated from the velocity, area, and density mentioned
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previously. High pressure air ejection systems are
examples of choked jet flow, and for this case the simplest
way to reduce noise is the resort to mechanical rather than
pneumatic ejection. Another method is to reduce the
velocity but retain the thrust by utilizing multiple
nozzles. Since the width of high velocity portion extends
only up to approximately two jet diameters6, maximum
thrust of the air ejection system can be obtained by
accurately aiming the jet stream at the target. Further
turbulence caused by sharp bends or other obstructions
upstream of the nozzle can be reduced by streamlining the
jet stream path.
Vibration can be caused by unbalance of rotating members,
and by changes in velocity of oscillating parts, such as
bell cranks, and of reciprocating components, such as
pistons or rams. The periodic force resulting from unbalance
of rotating members increases with an increase in the speed
of rotation. It it important therefore, to minimize the
magnitude of the unbalance by dynamic balancing. Because
increasing speed results in greater forces and higher noise
levels, it is useful to use a larger, but slower machine: an
example is a large diameter blower running at a slower speed
in lieu of a smaller diameter unit operating at a higher speed.
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Finally, noise in machinery may be electro-magnetic in
origin. In electro-magnetic devices, vibrational forces
are generated by the attraction and repulsion of magnetic
fields. Reduction of this type of noise may be accomplished
by proper redesign or by reducing the effect of the leakage
flux. Replacing magnetic materials which are not part
of the desired flux path with non-magnetic materials is
a design objective. The directional property of magnetic
fields may also be used to reduce the noise effects on
nearby parts. An excellent discussion of magnetic noise is
presented in Reference 7.
General methods for reducing noise at the source are described
in Table 7.2.2-1.
7.2.3 Transmission Path Noise Control
Noise sources may be coupled to other structural members
through solid, air, or magnetic paths, which in turn may
vibrate and reradiate sound. The transfer of energy
through solids or air is common to most machinery.
Reduction of magnetic coupling may be achieved by removing
unnecessary magnetic materials or replacing them with non-
magnetic materials such as brass, aluminum, or non-magnetic
stainless steel.
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Table 2.2.2-1 - Basic Techniques for Machinery Noise Control
2
(At the Source)
i
10
Impact
Friction
Fluid (Air) Turbulence
Forced Vibration
Electro-Magnetic
- Reduce Deceleration, Damp Source Pieces, Reduce Hardness
of .Impacting Surfaces, Reduce Size of the Source.
- Damp Source Pieces, Reduce Hardness or Rubbing Surfaces,
Reduce Source Size, Lubricate Surfaces.
- Reduce Air Velocity, Remove Obstructions, Polish Rough
Surfaces.
- Balance Parts, Reduce Acceleration, Add Tuned Dampers, Operate
Off-Resonance.
- Reduce Leakage Flux, Remove Nearby Magnetic Materials,
Orient Magnet for Minimurr Coupling.
-------
Since structureborne noise is common to most machinery,
it will be discussed in some detail. Mechanical or
structural coupling may be reduced by using a compliant
link between the two vibzating members, which mismatches
the impedance between the two paths. An example of this
is the use of flexible hose in piping systems. Another
method of providing compliance is by vibration isolation
of the source from the radiating structure. The selection
of vibration mounts must be made so that the resultant
combination has low transmissibility. Excellent treatments
of the transmissibility for vibrations and shock isolation
are given in the literature8.
When the transmission path or coupling is air, attenuation
of the airborne noise may be achieved by suitable construction
of partial or full enclosures. Whenever a machine or
machine parts is enclosed, it becomes necessary to isolate
the enclosare mechanically from the machine structure so
as not to transmit acoustic energy via a vibratory path.
When the machine is located in a highly reverberant area,
the resultant noise may also be reduced by treating the
area surfaces with sound absorbing materials. In practice,
the noise reduction achieved by this means is limited to
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approximately 7 to 10 decibels. Noise reduction obtained
by the use of sound absorbing materials is useful when the
exposed person is in the reverberant field. Excellent
discussions of enclosure design and the transmission loss of
structures are found in the literature9'1°'ll'12. Among
the many transmission paths through which noise may be
propagated are the special case of ventilation ducts.
One of the requirements of a ventilation duct system is that
the air flow and static pressure requirement be maintained,
but the noise transmission through the system be minimized.
These requirements can be satisfied by introducing acoustical
attenuating devices. These devices consist primarily of a
suitable reactive or dissipative muffler to obtain the
required noise reduction. The acoustical performance of
mufflers is affected by the high gas velocities/pressures,
and temperatures that are usually encountered in industrial
plants. For combating corrosion in industrial plants,
mufflers may be provided with stainless steel or synthetic
fibers as acoustical absorbent materials. A thorough
discussion of the design of reactive and dissipative mufflers
is available in standard texts and other publications13'11*'15
Noise from the source may be transmitted to structures as
mechanical vibration which may then radiate as noise into
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the environment. The response of a fibrating surface to
airborne or structureborne noise depends upon the mass,
stiffness, damping, and surface area of the structure.
Radiating surfaces may act as noise amplifiers at resonance.
In general, most mechanical structures have a greater
number of multiresonance frequencies at higher frequencies
than at lower frequencies. Noise reduction can be obtained
by damping the resonant members, increasing stiffness or
mass to shift the resonance frequency, and decreasing
surface area.
The effectiveness of vibration damping materials depends
upon their efficiency in converting vibratory mechanical
energy into heat. Some materials have high internal damping.
Sheet lead for instance,has more internal damping than
sheet steel; however, it is not always possible to use lead
as a structural material. In such cases, external damping
material may be applied.
The theory of vibration damping is well known16 There are
three types of vibration damping: friction damping, homogeneous
damping, and constrained layer damping. In friction or
coulomb damping, energy conversion takes place through
friction between the damping material and the vibrating surface.
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Jute, cotton fibers, wood fibers, and foams are among the
best friction damping materials. Glass fibers and other
cellular and fibrous materials which have a high internal
damping and high stiffness are effective homogeneous
or extensional damping materials. The most effective
damping materials in use at this time have a plastic base
and are available in liquid or sheet form17. Constrained
layer damping consists of a layer of homogeneous damping
material or thin metal foil separated from the vibrating
surface with an intervening layer of viscoelastic material.
In constrained layer damping, the dissipation of mechanical
energy is effected by shear motion of the constraining
damping material.
Radiation of low frequency sounds may be reduced by using a
smaller sufface area. The use of perforated or expanded
metal reduces the noise radiation from the sheet metal guards
or cover pieces. It is also necessary to isolate a machine
cover from vibration of the .machine'by use of resilient
gaskets and grommets. The important concepts discussed
above are summarized in Table 7.2.3-1.
7.2.4 Machinery, Equipment, and Process Noise Control
In the following sections, the generalized comments regarding
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Table 7.2.3-1 - Noise Reduction Methods
I. Plant Planning
a) Selection of Equipments
b) Location of Equipments Within the Plant
c) Location of Plant With Respect to the Community
II. Control at the Source
a) Maintain Dynamic Balance
b) Minimize Rotational Speed
c) Decouple the Driving Force
d) Reduce Velocity of Fluid Flow
e) Reduce Turbulence
f) Use Directionality of Source
III. Control of the Transmitted Noise
a) Vibration Isolate the Source
b) Enclose the Source
c) Absorb Sound Within the Room
d) Use Reactive or Dissipative Mufflers
IV. Control of Radiated Noise
a) Increase Mass
b) Increase Stiffness
c) Shift Resonant Frequencies
d) Add Damping
e) Reduce Surface Area
f) Perforate the Surface
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source and transmission path noise control discussed in
Sections 7.2.2 and 7.2.3, will be related to the major
noise sources observed at typical industrial plants. These
major noise sources are presented below in an order of
priority for noise abatement efforts in the authors'
opinions. The ordering procedure considers noise levels
and widespread use of the equipment.
(a) Compressors
(b) Fans and Blowers
(c) Industrial Gas Turbines
(d) Pumps
(e) Pneumatic Tools
(f) Reduction Gear Systems
(g) Metal Fabrication (Presses)
(h) Furnaces and Flare Stacks
(i) Valves
(a) Compressors
The noise generated by axial flow compressors has been the
subject of numerous investigators 2*~38. The noise from an
axial compressor results from the interaction of the rotor
with the stators or other obstacles in the flow path, and
consists of discrtete frequency noise and broad-band noise.
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The mechanisms of compressor noise radiation are essentially
aerodynamic in origin and consist of two unsteady flow
components: first, the wake field behind each blade, and
second, the turbulence induced in these wakes. The wake
interaction effects give rise to the discrete frequency
noise radiation, while the turbulence in the flow gives
rise to broad-band noise. The noise at the discrete
frequencies are the tones appearing at the rotor blade
passing frequency and multiples of this frequency, and are
the predominant source of compressor noise. The discrete
frequencies occur commonly in the range of 1000 to 5000 Hz,
and are important therefore, in determining the subjective
annoyance of compressor noise.
There are several methods of reducing the noise levels
mentioned in the literature, such as increasing the number
of rotor blades, using higher vane/blade ratios, and
enlarging blade row spacings. Other variables remaining
constant, experiments show that increasing the rotor blades
from 20 to 80 reduces the noise generated at the blade
/
passage frequency by approximately 10 dB; increasing the
vane/blade ratio from 1.0 to 2.0 there is an 8 dB reduction
in noise levels; and increasing the blade row spacing from
0.1 to 2.0 spacing/chord ratio there is a reduction of
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more than 10 dB at the blade passage frequency. Thus
it is clear that the reduction of noise at the source is
practicable and should be utilized in the design of
compressor systems.
The noise characteristics of large centrifugal compressors
has been the subject of recent studies39'1*0. The noise
spectrum depends upon the drive configurations (gear
reducers), compressor geometry, operating load range, and
the fluid being compressed. High tip speed needed for
centrifugal compressor operation can be achieved either
by a large diameter impeller at low speeds, or a small
diameter impeller at relatively high speeds. Compressor
rotational speeds ranging from 3600 to 20,000 rpm are common,
and the drive geometries employed in commercially available
equipment have a significant effect on the noise produced.
For example, the results of noise measurements over a
capacity range from 90 to 4000 tons of refrigeration, show
that the noise levels of these centrifugal compressors
range from 89 dB(A), to 102 dB(A), independent of equipment
size, drive configuration, fluid, or horsepower. The
noise spectrum is a combination of broad-band noise
associated with fluid flow turbulence and a series of discrete
frequencies associated with the blade passage frequency
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of the impeller plus harmonics, electro-magnetic noises
in the motor, mechanical unbalance in the drive configuration,
and gear tooth contact frequencies. There is an increase
on the order of 5 dB in the octave band containing the blade
passage frequency (500 to 2000 Hz) for compressors working
at loads less than 50 percent of full load.
At present, there is little information available on the
reduction of compressor noise at the source. However,
significant advances have been made in the art of muffler
and enclosure design.
Application of current theory to the design of mufflers,
vibration damping materials, fans, acoustical enclosures,
etc., has resulted in the reduction of the noise of stationary
and portable compressor systems. Noise from portable
compressors producing 900 scfm of air at 100 psig, has
been reduced from 100 dB(A) to 85 dB(A) by application of
current noise reduction techniques to the airborne and
structureborne transmission paths'11. In a similar manner,
large stationary compressor noise has been reduced from
106 dB(A) to 74 dB(A) .
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(b) Fans and Blowers
Fans and blowers are air handling devices which transfer
energy to air without significant compression. Axial
flow fans operate against little or no static pressure and
are rarely used in industrial applications, where fans
and blowers have to work against higher static pressures
and where large volumes of air are to be moved. For this
reason, centrifugal fans and blowers are generally used in
industrial applications. The discussion in this section
will be restricted to the study of noise abatement of
centrifugal blowers at the source. Aerodynamic noise from
the centrifugal blower consists of a rotational noise at
the blade passage frequency and its harmonics and vortex
noise, which is broad-band in character1*2. Noise generated
from blowers (fans) has been studied experimentally and
semi^-empirically by various investigators1*2 52. In
general, the broad-band aerodynamic sound power of a centri-
fugal blower is approximately proportional, for mach numbers
less than 0.6, to the 5th power of blade tip speed, and the
first power of mass flow1*7'1*8. It should be mentioned that
as yet there exists no analytical model for the noise
generating mechanism of centrifugal blowers. Experimental
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studies of the noise in centrifugal blowers show some
marked improvement in noise reduction by proper design of
the scroll, the cut-off clearance, and by sloping the tips
of the impeller blades with respect to the scroll. For
low noise levels, the scroll of a centrifugal machine
should have the shape of an involute where the axial clear-
ance increases in direct proportion to the angle traversed1*2.
If the scroll clearance increases more rapidly, it causes
abrupt pressure changes at cut-off and thus, increases the
noise levels at the blade passage frequency. The cut-off
clearance is an important factor in the design of blowers
for low noise levels. The noise generated at the cut-off
increases with a decrease in the cut-off clearance. Experi-
mental investigation of noise produced by centrifugal
blowers, with forward, backward, and radial blades at various
speeds, capacities and pressures, shows that the noise level
at the blade passage frequency and its harmonics may be
reduced as much as 12 dB, either by locating the cut-off
at the optimum clearance relative to the tips of the impeller,
or by sloping the edge of the cut-off relative to the tips
of the impeller blades52. By twisting of the impeller
blades, broad-band aerodynamic noise may be reduced by
1 or 2 dB52.
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Important external sources of noise generated by the impeller
are: housing radiation, inlet noise, and outlet noise. The
noise radiation from the housing can be reduced by using
heavier blower construction or by enclosing the blower.
The inlet and outlet noise are reduced by using sound traps
and mufflers at the inlet and outlet. The sound trap must
be designed to meet noise reduction and air flow capacity
requirements for the particular situation.
In an induced draft fan air handling system, the main
source of noise is the discharge (exhaust) stacks. The
intake is usually enclosed by ductwork and not a major
source of noise. In the forced draft systems, fan noise
emanating from discharge units is mostly dissipated within
the air preheaters and boilers being supplied by the fan.
In the forced draft fan systems, the fan inlet is the major
source of noise. If the fan draws air from outdoors, the
fan inlet noises must be reduced to eliminate noise complaints
from neighborhood residential areas. Methods of reducing
inlet or exhaust noise from forced draft or induced draft
fan systems using silencers have been discussed in the
literature53'1*3'55. Prefabricated silencer units to suit
the particular situation are commercially available. Noise
radiated from the shell of the fan housing and connecting
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ductwork can be reduced by using a heavier and stiffer
shell, damping treatments/ and by lagging the outside of
the duct.
(c) Industrial Gas Turbines
There is very little information available in the literature
on the reduction at the source of noise of industrial gas
turbine installations. Gas turbines are used in industrial
plants to drive other devices, such as generators, pumps, or
compressors. The main sources of noise are the intake and
exhaust of the turbine system. The noise at the intake is
characterized by a high frequency shrill noise, corresponding
to the blade passage frequency of the first stage of the
compressor. For a 20 megawatt gas turbine generator
installation, the intake noise level may be as high as 140 dB18,
The noise at the exhaust is associated with the mass flow
through the turbine exhaust, and is predominantly of a low
frequency nature with a high frequency content corresponding
to the blade passage frequencies of the turbine. In certain
frequency bands the noise level due to the exhaust may be as
high as 130 dB. ,Under these conditions, the noise level at
large distances from a power plant may be higher than the
ambient by as much as 15 to 40 dB during the daytime18.
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Intake and exhaust silencers are required to provide an
insertion loss of 20 to 40 dB in the low frequency range,
and 40 to 60 dB in the high frequency range to meet
community noise criteria. For control of turbine noise,
commercial silencers are available and range from six to
25 feet or more in length. A general discussion of the
design considerations for silencers has been given in the
literature19"23. In the past, the noise levels for gas
turbine installations have been determined mainly by the
manufacturer. Because of community reaction to industrial
noise, the trend in the future may be that noise specifica-
tions for gas turbines will be developed by the purchaser.
(d) Pumps
The noise in hydraulic systems are primarily due to sudden
changes in velocity and pressure, cavitation, fluid turbulence,
mechanical noise, and from pressure-reducing valves. The
piping system readily transmits noise to support systems and
surfaces which eventually radiate the noise into the environment,
There is a little information available in the literature on
the noise generated by pumps and hydraulic equipment and on the
methods used for designing quiet equipment56 60. The present
design methods are empirical. At present, there is a need
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for better understanding of the intrinsic pumping
mechanism as it relates to noise and the effects of design
variation on pump noise, since little quantitative inforr
mation on these factors is available. Some of the methods
used for reducing noise from pumps and piping systems are:
1. Vibration isolate pumps and motors to avoid
transmission of fluid pressure pulsations.
2. Install acoustical filters designed for the pump
or motor speed.
3. Use flexible hydraulic lines and flexible electrical
connections in making connections to vibration
isolate units.
4. Lag or apply external treatment to the piping system.
5. Enclose pump and drive unit in acoustical enclosure.
(e) Pneumatic Tools
Pneumatic tools have long been recognized as a source of high
noise levels in industry. Pneumatic tools can be classified
^
into three groups: rotary, piston, and percussion type.
Rotary tools consist of grinders, polishers, screw drivers or
drills; piston type devices are used in hoists, heavy duty
drills, and nut runners; percussion type'tools consist of
chippers, sealers, riveters, and pavement breakers. Pneumatic
tools can develop power of over five horsepower and have an
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operating speed ranging from 3000 to 25,000 rpm. The
noise levels produced by typical pneumatic tools are
given in Table 7.2.4-1. When a large number of these
tools are used, such as in mass production operations,
together they produce excessively high noise levels. At
the present state-of-the-art, the detailed mechanism of
the noise production of pneumatic tools is not well under-
stood. However, the noise created by pneumatic tools is
airborne, and the major offender is the air exhaust68'69.
The frequency of the discrete component of the noise is
computed from the blade passage frequency of the motor as:
the speed in rpm x number of vanes (pistons)
60
The noise of pneumatic tools may be reduced by:
1, Reduction of the noise at the source,
2. Reduction of the noise radiated by the outer casing,
and
3. Reduction of the noise from the exhaust.
At present, little is known about the reduction of the noise
at the source, and because of the small area of the casing,
radiation from the casing is small. However, studies show
that significant reduction of the exhaust noise is possible
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Table 7.2.4-1 - Some Representative Pneumatic Tool Noise Levels
Noise Level
dB(C)
Harmful Pneumatic Chipper (5 Feet) 125
Three-inch Grinder (3 Feet) 110
Objectionable Pneumatic Hoist (5 Feet) 93
Large Pneumatic Drill (1-1/2 feet) 92
Safe Pneumatic Screw Driver (1-1/2 feet) 80
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using mufflers or silencers at the exhaust. Specially
designed reactive mufflers of the single, double expansion
chamber, and pi-type configuration have been successfully
used to obtain substantial reductions of the order of
about 20 dB of more. Where the muffler is properly designed,
reduction of the order fo 40 dB at the blade passage
frequency and 20 dB for the overall noise is possible.
The state-of-the-art in muffler design has reached the
point where optimization techniques have been applied to the
design of reactive mufflers.
(f) Reduction Gear Systems^
Geared systems are extremely noisy. Gears consist of
assemblies of toothed wheels used for the purpose of torque
conversion, speed change or power distribution. The main
sources of noise in geared systems are:
1. Mechanical unbalance of the gear assembly,
2. Impact caused by tooth contacts,
3. Friction due to the contact motion of the tooth,
4. Variation of radial forces, and
5. Air and oil pocketing71'72.
Some of the principles used for reducing noise in gear
systems are:
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(a) Selection of a suitable type of gear (for
instance, a helical gear is quieter than a spur
gear, and a worm gear is still quieter, but is
restricted to low speeds),
(b) Accuracy of manufacturing (high accuracy in all
gear parameters results in quieter gear systems),
(c) Detuning (when the operational frequency of the
gear assembly coincides with the natural frequency
of the structural members, resonance takes place
amplifying the noise; to avoid resonance, the
structural members are detuned to other frequencies
by either stiffening or mass loading),
(d) Damping (introduced by using gear material of high
internal damping),
(e) Vibration isolation, and
(f) Enclosing the gear assembly (with particular
attention given to cooling and heat transfer
requirements).
Recent studies in gear system noise73'71* provide interesting
guidelines for the purchase of gears, including information
as to noise considerations. Figure 7.2.4-1 and Table 7.2.4-2,
describe the noise quality classification of geared systems
in terms of noise levels and the transmitted horsepower.
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Table 7.2.4-2 - Gear Noise Classification
(From References 73 and 74)
CLASS A: Noise Behavior Cannot be Reliably Obtained Even with High
Quality Production Techniques. Additional Sound Absorption,
Vibration Damping, Vibration Isolation, Structural Reinforement
Are Often Required.
CLASS B: -Result of Extremely High Manufacturing Accuracy and Control.
CLASS C: High Manufacturing Accuracy.
CLASS D: Normal Manufacturing Quality Required.
CLASS E: Gear Drives with High Noise Levels that are Easily Corrected
By Increasing the Manufacturing Quality,,
-289-
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Figure 7.2.4-1.
i
to
vo
o
I"?
O
A
)
1
I
130
120 --
110 . .
110--
90--
80..
70..
60__
Noise Quality Classification for Geared Systems
(From References 73 and 74)
10
10
Classification
10
Transmitted Power H. P.
10
10
-------
Table 7.2.4-3 provides the noise reductions that are
possible by appropriate adjustment of design parameters7*.
Confronted with a noise specification, the gear vendors
vary greatly in their sophistication in handling noise
problems. Present day trends in making quiet gears take the
direction of making precision gear systems and housing them
in heavily damped enclosures. Future trends in quieting
gear systems lies in using a systems dynamics approach "-to
control noise in the design stage itself71*.
(g) Metal Fabrication (Presses)
Most metal fabricating operations contain one or more of
the following: shearing/ blanking, punching, and forging. All
these, in general, involve the forming or cutting of metal
using dies. Operations involving shearing, blanking and
punching are performed in punch presses,with short duration
of the impact forces, •:Because of the short duration of the
impact forces, the noise is strongly dependent on the maximum
amplitude of the force. The three basic methods of controlling
impact noise are 8*'8 5:
(a) Control the noise at the source by controlling
the duration and magnitude of the impact forces,
(b) Modify the structureborne noise transmission path
by vibration isolation, or reduce vibration amplitudes
of the housing and foundation at resonance frequencies
by the use of appropriate damping, and
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Table 7.2.4~3 - Available Noise Reductions for Geared Systems
(From Referen ce 74)
Design Parameter
Profile Error
Profile Roughness
Tooth Spacing Error
Tooth Alignment Error
Speed
Load
Power
Pitch
Contact Ratio
Angle of Approach and Recess
Pressure Angle
Helix Angle
Noise Reduction
indB
0-5
5-10
3-7
3-5
0-8
% 20 log r~
20 log (j—)
o
% 20 log
Not Known
0-7
Not Known
Not Known
2-4
o o
Remarks
Normal Manufacturing
Ultra Precision Gears
Full Range of Standard Manu-
facturing Techniques
Basic Data V = Speed
Basic Data, High Loads and
Speeds L= Load
Basic Data
Finer, Quieter
Largest Best, But if Small
Contact Ratios are Necessary,
Use 2.0
Approach Forces Higher...
Smaller Approach Angle
Quieter
Lower Pressure Angle, Quieter
For Changes from Spur to Helix
-292-
(continued)
-------
Table 7.2.4-3 (continued)
Design Parameter
Gear Tooth Backlash
Air Ejection Effects
Tooth Phasing
Planetary System Phasing
Gear Housing
Gear Damping
Bearing
Bearing Installation
Lubrication
Noise Reduction
IndB
0-14
3-5
6-10
Not Known
5-11
6-10
0-5
0-4
0-2
0-2
Remarks
If Excessive Backlash
If Too Little Backlash
5000 fpm or More
Not Practical
Practical
If Resonant
If Resonant or Needs Isolation
Adds Damping, Some Types May
Stiffen Structure
Can Increase Life and
Eliminate Some Frequencies
Filled Gearbox Quietest, but
Can Cause Other Problems
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(c) Reduce the levels of the noise in the enclosed
space by the use of absorbing structures or
baffles.
The nature of the metal working operations precludes the
approach described in (a) above. However, methods such .as
in (b) and (c), have been successfully used to reduce the
noise of these types of machines.
In operations involving shearing, blanking and punching using
punch presses, the large impact forces exerted by the
descending punch on the plate placed upon the die and the
shearing action take place simultaneously. If the lower
face of the punch is slightly inclined, only a portion of
the pate is sheared due to punch geometry. The maximum
force needed is reduced, but the total duration of the
applied force is increased. This reduction of impact force
produces less vibration of the machinery, resulting in a
reduction in the overall noise level.
In punching operations, reduction of noise level may be
achieved by use of stepped punches, where the punching of
successive holes occurs progressively. The characteristics
of the material being worked also affect the noise produced.
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Harder materials requires greater force, thus producing
higher noise levels. Metal working operations involving
stainless steel are noisier than those involving cast steel;
operations on brass and aluminum are relatively quiet81*.
Poor maintenance often results in higher noise levels.
For instance, often there is a second impact occurring in
improperly adjusted presses when the flywheel catches up
with the moving head an instant after the dies engage.
This double impact also subjects bearings, gears, and
clutch parts to extra wear, with a subsequent increase in
maintenance and cost.
Air ejection systems, which are used to eject small parts
or scraps from press dies, are sources of high noise levels.
Reduction of noise levels can be obtained by changes in
the methods of handling material, either by reducing the:jet
velocity using a multi-nozzle system, or by streamliningijthe
jet path, or mechanical devices may be used for ejection.
Reduction of structureborne noise can be effected by
vibration isolation of the machine components from the
support structure. Reduction of the noise in the environment
surrounding the machine may be obtained by suitably enclosing
the machine. Sound absorbent treatment of the ceiling and
walls of the room also aid in the reduction of environmental
noise.
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-------
Reduction of noise at the operator's station may be
achieved by suspending sound absorbers in the path of
severe noise radiation.
(h) Furnaces and Flares
Combustion is the major source of noise in process plant
furnaces. There is as yet no known practical way of
quieting a flame releasing millions of BTUs per hour.
There are two types of flames for a given heat release: a
short bluish intense turbulent flame, and a large brilliant
yellowish non-turbulent flame76. For thrust controlled
flames, noise generally varies as the second power of hear
release79'80'81, and therefore, a load variation (firing
rate) of 50 percent would result only in a 3 dB change in
i
noise levels. Reduction of furnace noise can be accomplished
by confining the combustion noise within the fire box.
In natural draft furnaces, noise reduction may be achieved
by completely enclosing the burner registers within
highly damped heavy plenum chambers. There must be no
radiation path from the burner to the outside of the fire box.
It it extimated that noise levels might be reduced to
80 to 85 decibels in front of the fire wall by using
this procedure76. Another method of noise reduction in natural
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-------
draft furnaces is using individual shrouded burners provided
with integral acoustical baffles which block the trans-
mission path through the individual burner air registers
to the inside of the fire box.
Information on the noise levels from more than 25 furnaces
show that noise output does not depend significantly on the
type of furnace82, even though the shape of the spectrum
may vary. In general, there seems to be about a 10 dB
increase in the overall sound power level of furnaces for a
ten-fold increase in the heat load82. '
\
An interesting description of the sources of process plant
noise and methods of noise reduction is given in Table 7.2.4-4
reproduced from reference 83.
Flares used to burn excess process plant gases may be sources
of community noise. Steam injection systems are used to
suppress smoke, luminosity, and combustion-related instabili-
ties. This injection is the major source of noise in the
flare75. The mechanism of noise production in steam
infection systems is the turbulence in the highly sheared
mixing region downstream of the jet nozzle. Multiport nozzle
system designs, which help in the initial mixing of the steam
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Table 7.2.4-4 - Sources of Noise and Methods of Noise Reduction
For Process Plant Equipment
(From Reference 83)
Equipment
Heaters
Motors
Airfin Coolers
Compressors
Source of Noise
Combustion at Burners
Inspiration of Premix Air
at Burners
Draft Fans
Ducts
Cooling Air Fan
Cooling System
Mechanical and Electrical
Fan
Speed Changer
Motors
Fan Shroud
Discharge Piping and
Expansion Joint
Antisurge Bypass
Method of Noise Reduction
Acoustic Plenum*, Seals Around Control
Rods and Over Sight Holes
Intake Silencer
Intake Silencer or Acoustic Plenum
Lagging
Intake Silencer, Unidirectional Fan
Absorbent Duct Liners
Enclosure
Decrease rpm (increasing Pitch)
Tip and Hub Seals
Increase Number of Blades**
Decrease Static Pressure Drop**
Add More Fin Tubes**
Belts in Place of Gears
Quiet Motor, Slower Motor
Streamline Air Flow
Stiffening and Damping (Reducing Vibration)
Inline Silencer and/or Lagging
Use Quiet Valves and Enlarge and Stream-
line Piping**
Lag Valves and Piping
Inline Silencers
-298-
(continued)
-------
Equipment
Engines
Miscellaneous
Table 7.2,4-4 (continued)
Source of Noise Method of Reduction
Intake Piping and Suction
Drum
Air Intake
Discharge to Air
Timing Gears (Axial)
Speed Changers
Exhaust
Air Intake
Cooling Fan
Turbine Steam Discharge
Air and Steam Vents
Educators
Piping
Valves
Pumps
Lagging
Silencer
Silencer
Enclosure (or Constrained Damping on Case)
Silencers on Intake and Discharge and
Lagging
Enclosure (or Constrained Damping on Case)
Silencer (Muffler)
Silencer
Enclosure Intake or Discharge or Both
Use Quieter Fan
Silencer
Use Quiet Valve
Silencer
Lagging
Limit Velocities
Avoid Abrupt Changes in Size and Direction
Lagging
Limit Pressure Drop and Velocities
Limit Mass Flow
Use Constant Velocity or Other Quiet Valves
Divide Pressure Drop
Size Adequately for Total Flow
Size for Control Range
Enclosure
*lf Oil-Fired, Provide for Drainage of Oil Leaks and Inspection. Omit Liner Where Drips Collect.
**Usually Limited to Replacement Items on New Facilities.
-299-
-------
with the aspirated air, are useful in the reduction of the
noise in the steam jet76. Experiments show that an
increase in the initial mixing from 10 percent to 30 percent
of the aspirated air with steam results in a reduction
of the jet noise by more than 10 dB77.
Moisture condensation shocks can be developed by sudden
precipitation of moisture in a supersaturated state in a
steam injection system78.' For moisture content of as little
as two percent, this process of condensation is likely to
occur. There is very little information available on the
noise produced by the condensation shocks.
Combustion burner instabilities may be initiated by
variations in the rate at which gas is supplied and the
rate at which it burns. Since this instability may occur
only at certain combinations of gas supply rate (i.e.,
pressure) and gas burning speed (i.e., combustion), it is
possible that any gas change (adjustment of the purge-gas
system) should disrupt such instabilities76. In typical
stacks, the low frequency noise due to combustion driven
instabilities may cause resonance of the system. This can
be reduced by changing the standing wave system in the
stacks by use of inside baffles.
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(i) Valves
Control (pressure-reducing) valves are the primary cause
of piping system noise in process plants. The noise from
control valves has been studied by a few investigators61'66.
An understanding of the basic mechanism of noise generation
in control valves would eventually lead to effective design
for noise abatement.
The primary mechanism of the noise generation in pressure-
reducing valves is eddy-surface interaction, turbulent
mixing, and short/turbulence interaction. A discussion
of the noise produced by various types of valves is given
by Nakano61. The variation of sound power (at constant
pressure ratio and upstream temperature) has been expressed
as a function of mass flow rate raised to some power «,
where n is determined experimentally by class of valve.
Empirical methods of predicting valve noise in terms of flow
parameters, such as mass flow rate, upstream temperature,
molecular weight of the fluid, upstream to downstream
pressure ratio, and adiabatic index of the fluid, have been
developed. Significant advancement in the design of quiet
valves has been made by the application of Lighthill's
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theory67 of aerodynamic noise to the noise produced by
throttling valves. The most effective way to reduce
aerodynamic noise is by reducing the throttling velocity,
since the noise level varies as the eighth power of this
velocity. Other factors of importance are the effective
orifice diameter and the geometry of the valve trim!5.
Acoustical lagging is not an efficient method for reducing
noise downstream of a valve since lagging is useful only
for noise propagated through the pipe structure and not
through the fluid itself.
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APPENDIX A
REFERENCES
1. "Occupational Noise Exposure," Federal Register, Vol. 34,
N96, Part II, Section 50-204.10. Department of Labor
Safety and Health Standards, (May 20, 1969).
2. Sanders, Guy J. , "Noise Reduction in Machinery," Noise
Control 3_ (6), (November 1957), pp. 29-37, 62.
3. Crede, C. E., "Principles of Vibration Control," Chapter 12,
Handbook of Noise Control, edited by C. M. Harris, McGraw-
Hill Book Company, (1957).
4. Franken, P. A., "Jet Noise," Chapter 24, Noise Reduction,
edited by L. L. Beranek, McGraw-Hill Book Company,(1960).
5. Callaghan, E. E., et al., National Advisory Committee on
Aeronautics Technical Note 3590, (1955).
6. Industrial Noise Manual, Chapter 11, p. 121, American
Industrial Hygiene Association, Detroit, Michigan, (1966).
7. Fehr, R. D., and Master, D. F., "Electric-Motor and
Generator Noise," Chapter 30, Handbook of Noise Control,
edited by C. M. Harris, McGraw-Hill Book Company,(1957).
8. Crede, C. E., "Principles of Vibration Control," and
"Vibration Isolation," Chapters 12 and 13, Handbook of
Noise Control, edited by C. M. Harris, McGraw-Hill Book
Company, (1957).
9. Fehr, R. D., "The Reduction of Industrial Machine Noise,"
Proceedings of the Second National Noise Abatement Symposium,
Armour Research Foundation, Chicago, Illinois, (1951; , p. 99.
10. Mariner, T., and Park, A. D., "Sound Absorbing Screens,"
Noise Control ,2 (5), (September 1956), pp. 22-27, 58.
11. Bishop, D. E., "Use of Partial Enclosures to Reduce Noise
in Factories," Noise Control 3_ (2), (March 1957), pp. 65-69, 82.
A-l
-------
12. Rettinger, M., "Noise Level Reduction of Barriers," Noise
Control 3_ (5), (September 1957), pp. 50-52.
13. Davis, D. D., "Acoustical Filters and Mufflers," Chapter 21,
Handbook of Noise Control, edited by C. M. Harris, McGraw-
Hill Book Company, (1957).
14. Davis, D. p., Stokes, G. M., Moose, D., and Stevens, G. L.,
"Theoretical and Experimental Investigation of Mufflers
-with Comments on Engine Exhaust Muffler Design," NACA
Report 1192, (1954).
15. Kessler, P- M., "Application of Conjugate Gradient
Optimization Methods to Acoustic Filters Synthesis," Ph.D.
Thesis, Department of Electrical Engineering, Rutgers
University, New Brunswick, New Jersey, (1971).
16. Hamme, R. N., "Vibration Damping," Chapter 14, Handbook of
Noise Cp.n.trol, edited by C. M. Harris, McGraw-Hill Book
Company, (1957).
17. Emme, J. H., "Composite Materials for Noise and Vibration
Control, Sound and Vibration 4_ (7), (July 1970), pp. 17-21.
18. Hoover, R. M., "The Sound of Gas Turbine Installations,"
ASME Paper No. 70-WA/GT-6, presented at the Winter Annual
Meeting, New York, (November 29-December 3, 1970).
19. "Gas Turbine Sound and Its Reduction," National Electrical
Manufacturers Association Standards,Publication No. SM-33-1964.
20. Eckel, O. C., "Gas Turbine Silencers," ASME Paper No. 63-
AHGT-17, presented at the Aviation and Space, Hydraulic and
Gas Turbine Conference, Los Angeles, California, (March 1963).
21. McAuliffe, D. R., Morlock, H., and Oran, F. M., "What to Do
about Gas-Turbine Noise," ASME Paper No. 63-AHGT-77,
presented at the Aviation and Space, Hydraulic and Gas
Turbine Conference, Los Angeles, California, (March 1963).
22. Audette, R. R., "Sound Control for Gas Turbine Package Power
Plants," presented at the Conference of the American
Industrial Hygiene Association, Washington, D.C., (May 1962).
A-2
-------
23. Sanders, G. J., "Silencers, Their Design and Application,"
Sound and Vibration 2_ (2), (February 1968), pp. 6-13.
24. Bragg, S. L., and Bridge, R., "Noise from Turbojet Compressors,"
Journal of the Royal Aeronautical Society 6£, (1949), pp. 1-10.
25. Kilpatrick, D. A., and Reid, D. T., "Transonic Compressor
Noise - The Effect of Inlet Guide Vane Rotor Spacing,"
British National Gas Turbine Establishment, Report No. R257,
(1964).
26. Bateman, D. A., et al., "Compressor Noise Research," PAA-
ADS-31, (1965).
27. Tyler, J. M., and Sofrin, T. G., "Axial Plow Compressor
Noise Studies," Transactions of the Society of Automotive
Engineers, (1961), pp. 309-332.
28. Sperry, W. C., and Benzakein, M. J., "Experimental Results
of Vane/Blade Number Effects on Compressor Noise, American
Society of Mechanical Engineers, 13th Annual International
Gas Turbine Conference, (March 1968).
29. Lowson, M. V., "Compressor Noise Reduction," presented at the
Meeting of the Acoustical Society of America, (November 1966).
30. Benzakein, M. J., and Kazin, S. B., "A Theoretical Prediction
of Aerodynamically Generated Noise in Fans and Compressors,"
presented at the Meeting of the Acoustical Society of
America, (November 1968).
31. Benzakein, M. J., and Kazin, S. B., "Fan/Compressor Noise
Reduction," American Society of Mechanical Engineers
Paper No. 69-GT-9, (March 1969).
32. Benzakein, M. J., "A Study of Fan/Compressor Noise
Generation," National Aeronautics and Space Administration
Special Report - 207.
33. Benzakein, M. J., and Morgan, W. R., "Analytical Prediction of
Fan/Compressor Noise," American Society of Mechanical
Engineers Paper No. 69-WA/GT-10, (1969).
34. Shanland, I. J., "Sources of Noise in Axial Flow Fans,"
Journal of Sound and Vibration 1 (3), (1964), pp. 302-322.
A-3
-------
35. Chestnut, D., "Noise Reduction by Means of Inlet Guide
Vane Choking in an Axial Flow Compressor," National
Aeronautics and Space Administration Technical Note
D-4682, (July 1968).
36. Morfey, C. L., and Dawson, H., "Axial Compressor Noise:
Some Results from Aero-Engine Research," presented at the
Gas Turbine Conference of the American Society of Mechanical
Engineers, Zurich, (March 1966).
37. Benzakein, M. J., and Hocheiser, R. M., "Some Results of
Fan/Compressor Noise Research," American Society of
Mechanical Engineers Paper No. 70-WA/GT-12, (1970).
38. Lowson, M. V., "Theoretical Studies of Compressor Noise,"
Wyle Laboratories, Research Staff Report WR68-15,
(August 1968). (A bibliography on compressor noise is
included in this report.)
39. Webb, H. E., "Compressor, Household-Refrigerator and Room
Air-Conditioner Noise," Chapter 28, Handbook of Noise
Control, edited by C. M. Harris, McGraw-Hill Book Company,
(1957).
40. Blazier, W. E., Jr., "Noise from Large Centrifugal
Compressors,"Proceedings of the Purdue University Noise
Control Conference, R. W. Herrick Laboratories,(July 1971),
pp. 83-88.
41. "The First Quiet Portable Compressor," Sound and Vibration 3_ (5),
(May 1969), pp. 6-8.
42. Madison, R. D., and Wells, R. J., "Fan Noise," Chapter 25,
Handbook of Noise Control, edited by C. M. Harris, McGraw-
Hill Book Company,(1957).
43. Allen, C. H., "Noise Control in Ventilation Systems," Chapter 21,
Noise Reduction, edited by L. L. Beranek, McGraw-Hill Book
Company, (1960).
44. Beranek, L. L., Reynolds, J. L., and Wilson, K. E., "Apparatus
and Procedures for Predicting Ventilation System Noise,"
JASA 25, (1953), pp. 313-321.
A-4
-------
45. Peistrup, C. F., and Wesler, J. E., "Noise of Ventilating
Fans," JASA 25, (1953), pp. 322-326.
46. Beranek, L. L., Kamperman, G. W., and Allen, C., "Noise
of Centrifugal Fans," JASA 27_, (1955), pp. 217-219.
47. Goldman, R. B., and Maling, G. C., "Noise from Centrifugal
Fans," Noise Control 1, (1955), pp. 26-29.
48. Chipps, G. E., "Noise Produced by a Centrifugal Ventilating
Fan," M.E. Thesis, McGill University, (1956).
49. Huebner, G. H., "Noise of Centrifugal Fans and Rotating
Cylinders," Transactions of the ASHRAE 60, (1963),
pp. 181-189.
50. Maroti, L. A., and Pradhan, A. V., "Noise Generation
Characteristics of High Speed Centrifugal Fans," ASME- Paper
No. 69-WA/FE-9 presented at the Winter Annual Meeting,
Los Angeles, California, (November 1969).
51. Chanaud, R. C. , "Aerodynamic Sound from Centrifugal Fan
Rotors," JASA 37_ (6), (1965), pp. 968-974.
52. Embleton, T. F. W., "Experimental Study of Noise Reduction
in Centrifugal Blowers," JASA 35 (5), (1963), pp. 700-705.
53. Sanders, G. J., "Noise Control in Air Handling Systems,"
Sound and Vibration _! (2), (February 1967), pp. 8-18.
54. Sanders, G. J., "Silencers, Their Design and Application,"
Sound and Vibration :2 (2), (February 1968), pp. 6-13.
55. Hoover, R. M., and Wood, C. 0., "Noise Control for Induced
Draft Fans," Sound and Vibration 4_ (4), (April 1970),
pp. 20-24.
56. Shaw, A. M., "Make Your Pump Shut Up," Reprint No. 459,
Worthington Corporation, Harrison, New Jersey.
57. Evans, L. M., "How to Control Centrifugal Pump Noise,"
Reprint No. 894, Worthington Corporation, Harrison,
New Jersey.
A-5
-------
58. Meyerson, N. L., "Noise Reduction in Pumps and Pump
Systems," Noise Control 3_ (2), (March 1957), pp. 27-32, 91.
59. Szerlag, S. F., "Quieting Hydraulic Components," Proceedings
of the Purdue Noise Control Conference, Lafayette, Indiana,
(July 1971).
60. Callaway, D. B., "Noise in Water and Steam Systems,"
Chapter 26, Handbook of Noise Control, edited by C. M. Harris,
McGraw-Hill Book Company,(1957).
61. Nakano, A., "Characteristics of Noise Emitted by Valves,"
Paper No. F-172, The 6th International Congress on Acoustics,
Japan, (August 21-28,1968), p. 169.
62. Allen, E. E., "Prediction and Abatement of Control Valve
Noise," Paper No. 69-535, Annual Conference of the Instrument
Society of America, (1969).
63. Ribner, H. S., "Acoustic Energy Flux from Shock-Turbulence
Interaction," UTIAS Technical Note No. 108AFOSR 67-0221,
(July 1971).
64. Seebold, J. G., "Process Plant Noise Control at the Design
Engineering Stage," ASME Paper No. 70-PET-ll, presented at
the Petroleum Mechanical Engineering and Pressure Vessels
and Piping Conference, Denver,Colorado, (September 1970).
65. Bauman, H. D., "On the Prediction of Aerodynamically Created
Sound Pressure Level of Control Valves," ASME Paper No.
WA/FE-28, presented at the Winter Annual Meeting, New York,
New York, (November 29-December 3, 1970).
66. Schuder, C. B., "Control Valve Noise - Prediction and
Abatement," Proceedings of the Purdue Noise Control Conference,
Purdue University, Lafayette, Indiana,(July 1971), pp. 89-937
67. Lighthill, M. J., "On the Sound Generated Aerodynamically,
Part I," Proceedings of the Royal Society, London, (1952), and
••Part II," Proceedings of the Royal Society, London, (1954).
68. Chaffee, W. C., "Reduction of Noise in Industrial Pneumatic
Tools, Noise Control 1. (2), (March 1955), pp. 16-18, 67.
A-6
-------
69. Potschke, H., "Noise Reduction," Hydraulic Pneumatic Power,
(August 1966), pp. 490-492. (Translated from German original
published in "Oelhydraulik und Pneumatik.")
70. Kessler, F. M., and Puri, N. N., "Acoustic Filter Systhesis
Using Conjugate Gradient Search Techniques," JASA 49 (5),
(May 1971), pp. 1357-1361. —
71. Moeller, Kurt G. F., "Gear Noise Reduction," Noise Control
1 (2), (March 1955), pp. 11-15, 61.
72. Moeller, Kurt G. F., "Gear Noise," Chapter 23, Handbook of
Noise Control, edited by C. M. Harris, McGraw-Hill Book
Company,(1957).
73. Opitz, H. C. H., Zumbrouch, H., and Timmers, J., "Siriesunter-
uchungen des Gerauschverhaltens Moderner Hocklastgelriebe,"
Industrie-Anzeiger, Essen 87 Jg. Nr. 96, (November 1965).
74. Mitchell, I. D., "Gear Noise: The Purchaser's and Manufacturers
Views," Proceedings of the Purdue Noise Control Conference,
Lafayette^Indiana,(July 1971), pp.94-106.
75. Guide for Pressure Relief and Depressuring Systems, American
Petroleum Institute, Division of Refining, New York, API
RP 521, 1st ed., (September 1969), pp. 52-55.
76. Seebold, J. G., "Process Plant Noise Control at the Design
Engineering Stage," ASME Paper No. 70-PET-ll, presented at
the Petroleum Mechanical Engineering and Pressure Vessels
and Piping Conference, Denver, Colorado, (September 1970).
77. Seebold, J. G., and Hersh, A. S., "Refinery Flare Steam
Injectors Redesigned for Noise Control," ASME Paper No.
70-WA/PET-4, presented at the Winter Annual Meeting, New
York, (November 29-December 3, 1970).
78. Shapiro, A. H., The Dynamics and Thermodynamics of
Compressible Fluid Flow, Ronald Press, New York,fl953),
pp. 203-205.
79. Smith, T. J. B., and Kilham, J. K., "Noise Generation by
Open Turbulent Flames," JASA 315_ (5), (1963), p. 715.
A-7
-------
80. Smithson, R. N., and Foster, P. J., "Combustion Noise from
a Meker Burner," Combustion and Flame £, (December 1965),
p. 426.
81. Giammar, G. D., and Putnam, A. A., "Combustion Roar of
Turbulent Diffusion Flames," Journal of Engineering for
Power, Trans. ASME, Series A, 9_2 (2), (July 1970), pp. 157-165.
82. Davies, R. J., "Environmental Noise Control in Petroleum
Industry," Lecture presented at Concave Technical Meeting
on Environmental Noise Control held in The Hague, (20th March,
1968).
83. Judd, S. H., "Noise Abatement in Process Plants," Chemical
Engineering, (January 1971), pp. 139-145.
84. Crede, C. E., "Control of Impact Noise," The Acoustical
Spectrum, The University of Michigan Press, Ann Arbor,
Michigan, (February 1952), pp. 117-126.
85. Crede, C. E., "Principles of Vibration Control," Chapter 12,
Handbook of Noise Control, edited by C. M. Harris, McGraw-
Hill Book Company, (1957).
A-8
-------
APPENDIX B
SELECTED BIBLIOGRAPHY
1. Anderson, A. B. C.f "Structure and Velocity of the Periodic
Vortex-ring Flow Pattern of a Primary Pfeifenton (pipe tone)
Jet," Journal of the Acoustical Society of America 27 (6),
(1955), pp. 1048-1053.
2. Anderton, D., et al., "Origins of Reciprocating Engine Noise -
Its Characteristics, Prediction, and Control/" ASME Paper
70-WA/DGP-3, Winter Annual Meeting of the American Society
of Mechanical Engineers, New York, New York, (November 29-
December 3, 1970).
3. Bannister, R. L., and Thomas, R. J., "An Experimental
Mechanical Impedance Technique," Sound and Vibration 2 (3),
(March 1968), pp. 10-16.
4. Barry, G., "Measurement and Analysis of Noise in Factories,"
Journal of the Institute of Plant Engineers .8 (1) ,- (1962) ,
pp. 3-14.
5. Bonvallet, G. L., "Retaining High Sound-Transmission- Loss
in Industrial Products," Noise Control 3_ (2), (March 1957),
pp. 61-64, 92.
6. Boratynski, N., "Plant Planning for Noise Control," Noise
Control 2_ (4), (July 1956), pp. 37-46, 95.
7. Botsford, J. H., "Compressed Air Exhaust Mufflers," American
Industrial Hygiene Association Quarterly 15, (1954), p. 57.
8. Botsford, J. H., "Current Trends in Hearing Damage Risk
Criteria," Sound and Vibration £ (4), (April 1970),
pp. 16-19.
9. Bradgley, R. H., "Mechanical Aspects of Gear Induced Noise
in Complete Power Train Systems," ASME Paper No. 70-WA/DGP-l,
Winter Annual Meeting of the American Society of Mechanical
Engineers, (November 29-December 3, 1970).
10. Bragg, S. L., and Bridge, R., "Noise from Turbojet Compressors,"
Journal of the Royal Aeronautics Society 68 (637), (January 1964)
B-l
-------
11. Broadbent, D., and Little, E., "Effects of Noise Reduction
in a Work Situation," Occupational Psychology 34, (1960),
pp. 133-140.
12. Brozek, B., "Noise in High Speed Motors," Machine Design,
(March 5, 1970), pp. 123-127.
13. Callaway, P. B., "Reducing Noise in Machines," Machine
Design £3, (1951), p. 122.
14. Caudra, E., and Beland, R. D., "Rationale for the Compre-
hensive Control of Urban Noise," Proceedings of the Institute
of Environmental Sciences, (1970), pp. 236-243.
15. Chanaud, R. C., and Powell, A., "Some Experiments Concerning
the Hole and Ring Tone," Journal of the Acoustical Society
of America 37^ (5), (1965), pp. 902-911.
w J,.
16. Charson, G. L., "Will You Reduce the Noise on Your Design
for the 1970's," Hydraulics and Pneumatics 22 (11),
(November 1969), pp. 75-80.
17. Chestnut, D., "Jet Engine Inlet Noise Control," Sound and
Vibration 2_ (12), (December 1968), pp. 10-14.
18. Christman, R. P., Herbert, H. J., ,^and Bales, R. E., "Sound
Pressure Levels in the Wood Products Industry," Noise Control
2 (5), (September 1956), pp. 33-38, 72.
19. Cirlett, E. N., Mercombe, V. J., and Chandra, B., "Shielding
Factory Noise by Work-in-Progress Storage," Applied Agro-
nomics, (March 1970), pp. 73-78.
20. Clark, W., and Pietrasanta, A., "Community and Industrial
Noise," American Journal of Public Health 51,(1961),
pp. 1329-1337.
21. Cohen, J. A., and Jones, H. H., "'Sociocusis' Hearing Loss
from Non-occupational Noise Exposure," Sound and Vibration
4_ (11) , (November 1970) , pp. 12-20.
22. Cox, J. R., "Enclosure for a Can Davider," American Industrial
Hygiene Association Quarterly 15, (1954), p. 40.
23. Crawford, R., "Noise of Rotating Spindles and Bobbins in a
Textile Machine," Journal of Sound and Vibration 5 (2),
(March 1967), pp. 317-329.
B-2
-------
24. Crouch, H. W., "Controlling the Noise from Panel Press Areas,"
American Industrial Hygiene Association Quarterly 15, (1954),
p. 38. " —
25. Crouch, H. W. , "Noise Reduction by Enclosing Jordan Shredding
Machine," American Industrial Hygiene Association Quarterly
15, (1954), p. 40.
/'
26. Cudworth, A., "Field and Laboratory Examples of Industrial
Noise Control," Noise Control 5_ (1) , (1959), pp. 39-43, 73.
27. Damewood, G., Sparks, C. R., Hanchett, M. T. , and Brown,
M. E., "Blow-off Noise Suppression and Regulator Valve
Noise Generation," Noise Abatement at Gas Pipeline
Installations, Vol. Ill, American Gas Association, Inc.,
(November 1961).
28. Dyer, I., "Noise Attenuation of Dissipative Mufflers," Noise
Control 2_ (3), (May 1956), pp. 56-57, 78-79.
29. Edwards, G., "Design for a Quieter Future; How to Muffle
the Noisy Diesel," Design Engineering, Materials, and
Components, (15th October 1970), pp. 49-51.
30. Gardiner, R. E., Nordberg, K. S., and Silsbee, D. L.,
"Acoustical Foams for Sound Absorption Applications," Sound
and Vibration 4_ (7), (July 1970), pp. 12-16.
31. Geiger, P. H., and Hamme, R. N., "Methods for Reducing the
Noise of Industrial Machines," Proceedings of the Third Annual
National Noise Abatement Symposium,(1952), p. 19.
32. Granier, M. G., "Industrial Noise and the Neighborhood,"
Silence, (October/December 1967), pp. 9-11, (in French).
33. Griffiths, J. W. R., "The Spectrum of Compressor Noise of a
Jet Engine," Journal of Sound and Vibration ]L (2), (1964),
pp. 127-140.
34. Hahn, R. S., "Design of Lanchaster Damper for Elimination,"
Transactions of the ASME 75_, (1951) , p. 331.
35. Hahn, R. S., "Metal-Cutting Chatter and Its Elimination,"
Transactions of the ASME T5_, (1953), p. 1073.
36. Hardy, H. C., "Engineering and Zoning Regulations of Outdoor
Industrial Noise," Noise Control 3_ (3), (May 1957), pp. 32-38.
B-3
-------
37. Hetherington, R., "Compressor Noise Generated by Fluctuating
Lift Resulting from Rotor-Stator Interactions," American
Institute of Aeronautics and Astronautics "Journal 1^ (2),
(February 1963), pp. 473-474.
38. Hoover, R. M., and Williams, "Noise Control for Reciprocating
Compressors," Heating, Piping and Air Conditioning 34 (11),
(November 1963).
39. Hulse, B. T., and Large, J. B., "The Mechanism of Noise
Generation in a Compressor Model," ASME Paper 66-GT/N-42,
(April 1966), pp. 191-198.
40. Ingard, Uno, "Attenuation and Regeneration of Sound in Ducts
and Jet Diffusers," Journal of the Acoustical Society of
America 33_ (9), (September 1959), pp. 1202-1235.
41. Jackson, R. S., "Some Aspects of the Performance of Acoustic
Hoods," Journal of Sound and Vibration 3_ (1), (January 1966),
pp. 82-94.
42. Johnson, C. N., "Fractional Horsepower Rotary Vane Refrigerant
Compressor Sound Source Investigation," Purdue University
Ph.D. Thesis, (August 1969).
43. Junger, M. C., "Sound Transmission Through an Elastic
Enclosure Acoustically Closely Coupled to a Noise Source,"
ASME Paper 70-WA/DE-12, Winter Annual Meeting of the American
Society of Mechanical Engineers, New York, New York,
(November 29-December 3, 1970).
44. Kemp, N. H., and Sears, W. R., "Aerodynamic Interference
Between Moving Blade Rows," Journal of the Royal Aeronautical
Sciences 20 (7), (September 1953), pp. 585-598.
45. King, A. J., "Setting Standards for Machine Noise,"
Engineering 198 (5176), (1964), pp. 93-95.
46. Lane, R. N., "Silencer for Cat Cracker," Noise Control
3_ (6), (November 1957), pp. 48-50.
47. Lazarus, M., "How To Approximate Transmissibility Curves,"
Sound and Vibration 3_ (6) , (June 1969) , pp. 25-26.
48. Lo, N. K., and Rembold, U., "Development of Double Lobed
Cylinder for Rotary Vane Compressors," Proceedings of Semi-
Annual ASHRAE Meeting, Detroit, Michigan^(February 1967).
B-4
-------
49. Lowe, R. T., and Crede, C. E., "Recent Developments and
Future Trends in Vibration Isolation," Noise Control 3 (6),
(November 1957), pp. 21-28, 70. "
50. Lowery, R. L., "Compressor Valve Noise and Vibration Studies,"
Purdue University Ph.D. Thesis, (June 1969).
51. Maekawa, Z., "Noise Reduction of Screens," Applied Acoustics
1 (3), (July 1968), pp. 157-173.
52. Marsh, J. A., "The Airborne Sound Insulation of Glass,"
Paper presented at the British Acoustical Society Meeting
at Newcastle-upon-Tyne, (1970).
53. Mattei, J., "Planning for Noise Control of New Industrial
Plant," Journal of Sound and Vibration 4 (2), (September 1966),
pp. 249-255.
54. Meyerson, N. L., "Noise Reduction in Pumps and Pump Systems,"
Noise Control 3 (2), (March 1957), pp. 27-32, 91.
55. Mitchell, L. D., and Lynch, G. A., "Origins of Noise,"
Machine Design, (May 1, 1969), p. 174.
56. Mitchell, L. D., and Lynch, G. A., "Progress in Noise
Analysis," DuPont Innovations 1^, (1969), pp. 9-11.
57. Ogden, J., "Typical Examples of Noise Reduction in General
Motors Corporation," Transactions of the Annual Meeting of
the Industrial Hygiene Foundation, Pittsburgh, (1952).
58. Pietrasanta, A. C., "Fundamentals of Noise Control, "Noise
Control ^ (1), (1955), pp. 10-18.
59. Pish, R. H., and Hall, R. W., "Noise Reduction Techniques
as They Apply to Engine-Generator Design and Treatment,"
SAE Technical Paper 690755, Presented at the Natural Power
Plant Meeting, Cleveland, Ohio, (October 27-29, 1969).
60. Raes, A. C., "They Are Doing Something About Noise in Reducing
Valve Noise in Sugar Refinery," Noise Control 2_ (6),
(November 1956), pp. 55-56, 64.
61. Rees, W. M., "Acoustical Engineering Principles for Noise
Reduction," Noise Control 3 (2), (March 1957), pp. 59-60, 84.
B-.5
-------
62. Rice, C. G., and Walker, J. G., "Subjective Assessment of
Noise Spectra from Large Industrial Sites," Applied Acoustics
1 (3), (July 1968), pp. 189-203.
63. Robinson, I. F. S., and Shirley, M. B., "Noise Problems in
Large Refinery," Proceedings of the 6th World Petroleum
Congress, Section VII, (June 1959), pp. 309-3.26.
64. Rosen, M. W., "Noises of Two Spur-Gear Transmissions," Noise
Control ]_ (6), (November-December 1961), pp. 11-19.
65. Route, W. D., "Gear Design for Noise Reduction," SAE
Technical Paper 208E, (July 1, 1960).
66. Sacerdote, G., "Statistical Measurements of Factory Noise,"
Noise Control 5_ (6), (1953), pp. 29-31, 53.
67. Sallee, E., and Guy, A., "Punch Press Noise Control,"
American Industrial Hygiene Association Journal 1!? (5),
(1958), pp. 409-412.
68. Schaudinischky, L. H., and Schwartz, S., "On. the Acoustic
Problems of Cooling Towers," Applied Acoustics 1^ (4),
(October 1968), pp. 309-322, (in German).
69. Seiner, J. M., "The Design and Development of a Spinning
Mode Synthesizer," The Pennsylvania State University, M. S.
Thesis, (September 1969).
70. Slout, N. P., "Noise Characteristics of Textile Machinery,"
The Textile Institute and Industry, (March 1970), pp. 61-64.
71. Snow, W. B., "Engineering Solutions to Industrial Noise
Problems," Noise Control 2_ (4), (July 1956), pp. 72-76, 92.
72. Sparks, C. R., "Design of High Pressure Blow-off Silencers,"
Journal of the Acoustical Society of America 34^ (5) , (May 1962)
pp. 602-608.
73. Sz.erlag, S. F.., "Quieting Hydraulic Components," Proceedings
of the Purdue Noise Control Conference, Lafayette, Indiana,
(July 14-16, 1971), pp. 495-499.
B-6
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74. Tarn'oczy, "Vibration of Metal Plates Covered with
Vibration Damping Layers," Journal of Sound and Vibration
11 (3), (March 1970), pp. 299-307.
75. Tseo, G. G., "Estimating the Performance of Wall Structures
Used for Controlling Noise," Proceedings of the Purdue Noise
Control Conference, Lafayette, Indiana,(July 14-16, 1971),
pp. 115-122.
76. Walker, C. W. E., "The Powell River Suction Roll Silencer,"
Noise Control 2_ (5), (September 1956), pp. 39-45, 58.
77. Washburn, E. S., "Legal Developments in Industrial Noise,"
Noise Control 2 (4), (July 1956), pp. 68-70.
78. Wells, R. J., "Enclosures for Noise Reduction in the Factory,"
'American Industrial Hygiene Association Quarterly 15,
(1954), p. 59.
79. Wendt, E. H., "Techniques of Noise Control for Public
Utilities," Noise Control 3_ (5), (September 1957), pp. 37-40,
62.
80. Young, R., "Some Noise Control Methods Used in Industrial
Operations," American Industrial Hygiene Association Journal.
19> (6), (December 1958), pp. 520-527.
81. Zallen, D. M., "Analysis of Flow Changes at the Compressor
Face Resulting from a Blast Wave Impinging the Engine Inlet
of a Moving Aircraft," FZA-12-075, Fort Worth Division of
General Dynamics, Fort Worth, Texas, (April 1969).
B-7
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APPENDIX C
STANDARDS AND SPECIFICATIONS
1. CAGI-PNEUROP Test Code for the Measurement of Sound from
Pneumatic Equipment. Compressed Air and Gas Institute,
New York, New York, 1969. (ANSI S5.1 - 1971)
2. ASHRAE Standard 36-62: Measurement of Sound Power Radiated
from Heating, Refrigerating and Air Conditioning Equipment.
American Society of Heating, Refrigerating and Air-Conditioning
Engineers, New York, New York, February 1962.
{
3. ARI Standard 443-70: Sound Rating of Room Fan-Coil Air
Conditioners. Air Conditioning and Refrigeration
Institute, Washington, D. C., 1970.
4. ARI Standard 270-67: Sound Rating of Outdoor Unitary
Equipment. Air Conditioning and Refrigeration Institute,
Washington, D. C., 1967.
5. ARI Standard 446-68: Sound Rating of Room Air-Induction
Units. Air Conditioning and Refrigeration Institute,
Washington, D. C., 1968.
6. ARI Standard 275-69: Application of Sound Rated Outdoor
Unitary Equipment. Air Conditioning and Refrigeration
Institute, Washington, D. C., 1969.
7. ADC Test Code 1062 R2-C.14.0: Test of Sound Measurement.
Air Diffusion Council, Chicago, Illinois, 1966.
8. ADC Standard AD-63: Measurement of Room to Room Sound
Transmission Through Plenum Air Systems. Air Diffusion
Council, Chicago, Illinois, 1963.
9. IEEE Standard 85: Test Procedure for Air Borne Noise
Measurements on Rotating Electric Machinery. The Institute
of Electrical and Electronics Engineers, New York, New York,
February 1965.
10. NEMA Standard TR-27-5.09: Audible Sound Level Tests for
Commercial, Institutional, and Industrial Dry Type
Transformers. National Electrical Manufacturers Association,
New York, New York, 1965.
C-l
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11. NEMA Standard ST 1-4-2.7: Audible Sound Level Test for
Specialty Transformers. National Electrical Manufacturers
Association, New York, New York, 1961.
12. NEMA Standard SM 21-5: Sound Pressure Levels for Mechanical
Drive Steam Turbines, Multi-stage. National Electrical
Manufacturers Association, New York, New York, 1970•.
13. NEMA Standard SM 22-^5: Sound Pressure Levels for Mechanical
Drive Steam Turbines, Single Stage. National Electrical
Manufacturers Association, New York, New York, 1970.
14. NFPA Standard T 3.9.70.12: Method of Measuring Sound
Generated by Hydraulic Fluid Power Pumps. National
Fluid Power Association, Thiensville, Wisconsin, 1970.
15. AGMA 295.03: Specification for Measurement of Sound on
High Speed Helical and Herringbone Gear Units. American
Gear Manufacturers Association, Washington, D. C., '
December 1968.
16. IEEE Standard No. 85: Test Procedure for Airborne Noise
Measurements on Rotating Electric Machinery. The Institute
of Electrical and Electronics Engineers, New York, New York,
February 1965.
17. AMCA Standard 300-67: Test Code for Sound Rating Air Moving
Devices. Air Moving and Conditioning Association, Inc.,
Arlington Heights, Illinois, January 1967.
18. AMCA Rating Procedure 301-65: Standard Method of Publishing
Sound Ratings. Air Moving and Conditioning Association, Inc.,
Arlington Heights, Illinois, February 1965.
19. AMCA Certification 311-67: Certified Sound Rating Program
for Air Moving Devices. Air Moving and Conditioning
Association, Inc., Arlington Heights, Illinois, 1967.
20. NMTBA: Noise Measurement Techniques. The National Machine
Tool Builders Association, Washington, D. C., June 1970.
C-2
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APPENDIX D
INSTRUMENTATION, FLOW DIAGRAMS, and COMPUTER PRINTOUTS
The instrumentation systems used for this project are tabulated
in this Appendix. The manufacturer, type, model number, and
serial number are presented for each unit. Most instrumentation
systems (transducer through amplifier, record and playback)
contain non-linearities in frequency; that is the system frequency
response is not flat in the frequency range of interest. These
non-linearities can be compensated for by using a General Radio
Real-Time Analyzer. The necessary corrections are applied to
each one-third octave band from 25 hertz to 8000 hertz using the
GR multifilter.
This Appendix also contains the flow diagrams describing the
computer programs used for the various statistical computations
to which the data was subjected. Examples of the computer
printout;, in the form of statistical values, percentile values,
and noise level (A-weighted) histogram are also presented.
An instrumentation list, discussed above, of equipment used for
this program is presented in this Appendix as Table D-l. Table
D-2 lists the attenuatescorrections required because of wind-
screen, microphone, random incidence corrector, sound level meter,
D-l
-------
and Nagra/Crown tape recorder deviations from a flat frequency
response.
Flow charts describing the statistical data analysis are pre-
sented as Figure D-l, while the computer output format is shown
as Figure D-2. The noise level histograms were accomplished
using the PDP-8/I computer. An example of this histogram format
is presented as Figure D-3.
D-2
-------
Table D-l - Instrumentation List
Pistonphone Calibrator
Bruel & Kjaer Model 4220, Serial Number 96912
Bruel & Kjaer Model 4230, Serial Number 282298
Capacitor Microphone Cartridge
Bruel & Kjaer Model 4145, Serial Number 259598
Bruel & Kjaer Model 4145, Serial Number 270841
Bruel & Kjaer Model 4148, Serial Number 260219
Windscreen
Bruel & Kjaer Model UA-0207
Random Incidence Corrector
Bruel & Kjaer Model UA-0055
Extension Cable
Bruel & Kjaer Model AO-0028
Precision Sound Level Meter
Bruel & Kjaer Model 2203, Serial Number 96843
Bruel & Kjaer Model 2204, Serial Number 285686
Bruel & Kjaer Model 2206, Serial Number 253198
Octave Filter Set
Broel & Kjaer Model 1613, Serial Number 91513
Bruel & Kjaer Model 1613, Serial Number 257209
Magnetic Tape Recorder
Kudelski Nagra IVB, Serial Number 1349903
D-3
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Table D-2 - Attenuation Corrections
Frequency
25
31.5
40
50
63
80
100
125
160
200
250
315
400
500
630
800
1000
1250
1600
2000
2500
3150
4000
5000
6300
8000
10,000
12,500
16,000
20,000
Nagra IV
Crown 800
Scotch 175
7.5 ips
+3
+2.7
+.7
+.8
+3
+1
+1
0
+1
+1
+1
+.6
+ .6
+ .5
+.3
+.2
0
0
0
0
0
0
0
-1
-1
-1.2
-3
-6
-14
B&K 4145
Microphone
0
- 1
-.3
-.6
-1
-1.5
-2.2
-3.3
-4.4
-6.7
-7.5
-9.3
-10.5
-12.5
Random Windscreen
Incidence
Corrector
0 0
i
+.1 1
+ .1 +.1
+.2 +.2
+.2 +.3
+.3 +.5
+.4 +.4
+.9 +.1
+1.7 -.4
+3.0 -.7
+4.0 -.5
+6.4 -1.6
+6.0 -1.2
-2
Total
Correction
+3
+2.7
+.7
+.8
+3
+1
+1
0
+1
+1
+1
+.6
+.6
+.5
+.3
+.2
0
-.1
-,2
-.5
-.7
-1.4
-2.3
-4.1
-5.4
-5.2
-7.5
-11.7
Multifilter
Settings
-3
-3
-1
-1
-3
-1
-1
0
-1
-1
-1
-1
-1
-1
0
0
0
0
0
+1
+1
+1
+2
+4
+5
+5
+8
+12
D-4
-------
f
Start
Ask Number
of
Samples
"N"
Store
Octave Band
Data
Figure D-la. Paper Tape Generation Program for Statistical Analysis
D-5
-------
c
Start
Select
Input
Format
Process
Data
Select
Input
Format
Print
Output
Figure D-lb. Statistical Analysis Program
D-6
-------
C
Start
Ask Number
of
Samples
"N"
Compute
And
Store
dB(A)
Figure D-lc. Paper Tape Generation for Noise Level (A-weighted)
Histogram.
D-7
-------
C
Start
Ask Number
of
Samples
Read Punched
Tape,.
Type
Lowest Value
Highest Value
Ask
'Lowest Value
^Highest Value
Increment
Print
Histogram
Figure D-ld. Noise Level (A-weighted) Histogram
D-8
-------
** STATISTICAL VALUES **
MAX SPi *
MIN SPL *
NO, OF QCC.*
MEAN *
MEDIAN *
STO. DEV. *
OCTAVE BAMD
31,5 63 125 250
503 1000 2000 4000 8000
64
57
100
59.8
60
67
59
100
62,7
62
64
53
100
60.2
60
57
48
100
52.9
53
57
42
103
51.8
52
53
42
100
48,1
48
50
40
100
46,0
46
43
38
100
40.2
40
44
39
100
41,6
41
1.5
1.6 1.6 1,7 1.5
1,0 0.9
l.l
** PERCEMTUE VAUES **
OCTAVE L L L
BAND 90 50 10
#•<•**$ *************************
31.5
63,0
125.0
250.0
500,0
1000.0
2000,0
4000,0
8000.0
LINEAR
A-WT
B.-WT
OWT
D-WT
*
*
*
*
*
*
*
*
0
*
*
*
*
*
58
61
58
51
50
47
45
39
40
64
52
58
64
60
SIU
47
60
62
60
53
52
48
46
40
41
66
54
59
65
6?
49
51
55
52
55
54
50
47
41
43
58
56
52
57
54
50
^t **#**********#***#*#**##***#******************************##
Figure D-2. Sample Statistical Analysis Computer Printout
D-9
-------
OF SAMPLES:50
::::::::::::::::::::::::::::::::::::*::::::
LOWEST VALUE 44-32
HIGHEST VALUE 49-60
TYPE IN INTEGER VALUES FOR THE LOWEST VALUE* HIGHEST
VALUE* AND INCREMENT
LOWEST VALUE:40
HIGHEST VALUE:50
INCREMENT:1
REEL oi RUN 006 ENG AJD DATE 6-22-71 Location 5 Night Glass Manufacturing
Plant
40
41
42
43
44 **
45 *************
46 *****************
47 ***********
4g *****
49 **
50
NUMBER OF OCCURRENCES
Figure D-3. Sample Noise Level (A-weighted) Histogram Printout
D-10
------- |