NTID300.1
NOISE  FROM CONSTRUCTION EQUIPMENT AND
    OPERATIONS, BUILDING EQUIPMENT,
          AND HOME  APPLIANCES
               DECEMBER 31, 1971
         U.S. Environmental Protection Agency
              Washington, D.C. 20460

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                                                                      NTID300.1
    NOISE FROM  CONSTRUCTION EQUIPMENT AND
         OPERATIONS, BUILDING EQUIPMENT,
                AND  HOME APPLIANCES
                     DECEMBER 31, 1971
                         Prepared by

              BOLT, BERANEK AND NEWMAN
                            under
                   CONTRACT  68-04-0047
                           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.
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20102
                Price $3.15 domestic postpaid or (3 OPO Bookston

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                       TABLE OF CONTENTS
PREFACE 	  Hi
ACKNOWLEDGEMENTS 	 	    v
LIST OF FIGURES 	    x
LIST OF TABLES 	 xlil
SECTION 1.   INTRODUCTION 	    1
            1.1  Source Characterization 	    2
            1.2  Impact Evaluation 	    3
            1.3  Industry Assessment 	    5
SECTION 2.   SOURCE CHARACTERIZATION 	    7
            2.1  Construction Equipment and Operation 	    7
            2.2  Home Appliances 	   27
            2.3  Building Equipment 	   53
SECTION 3 •   IMPACT 	   62
            3.1  Noise Level Criteria for Impact
                 Evaluation 	   62
            3.2  Construction Noise	   70
            3-3  Appliances 	   9^
            3.4  Projections of Construction and
                 Appliance Noise to the Year 2000  	  119
SECTION 4.   INDUSTRY EFFORTS	  130
            4.1  Introduction 	  130
            4.2  Construction Industry Efforts 	  132
            4.3  Building Equipment and Appliance
                 Industry Efforts  	  144
                               iii

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                 TABLE OF CONTENTS (Continued)
                                                            page
SECTION 5-  CONCLUSIONS AND RECOMMENDATIONS 	  163
            5.1  Conclusions 	  163
            5.2  Recommendations 	  170
            5-3  Economic Impact Studies '*-.:....•.	  178
            5.4  A Program of Public Support Development ..  180
            5.5  Social Impact .		  182
REFERENCES 	  185

APPENDIX A. DETAILED SOURCE CHARACTERIZATION 	  A-l
            A.1  Construction Equipment 	  A-l
            A. 2  Appliances 	  A-9
            A. 3  Typical Equipment in Buildings  	 A-22
REFERENCES 	 A-38
APPENDIX B. IMPACT CONSIDERATIONS 	 	  B-l
            B.I  Interpretation of Impact Estimates  	  B-l
            B.2  Discussion of Construction Data 	  B-3
            B.3  Estimating the Extent of Public Works
                 Construction Noise 	  B-6
            B.4  Propagation Loss Model for Building
                 Construction Sites in Metropolitan
                 Areas 	  B-8
APPENDIX C. SOUND LEVEL CONSIDERATIONS 	  C-l
            Noise - The Problem Stated 	  C-l
            The Concern for Noise 	  C-2
            What Are Manufacturers Doing About Noise? 	  C-4
            The Complex Answers 	  C-5
            Quieting Current Products 	  C-7
                                iv

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                 TABLE OF CONTENTS (Continued)
                                                            page
            Future Machine Quietness	  C-7
            Noise Standards and Regulations  	  C-8
APPENDIX D. NOISE CONTROL: REGULATION AND STANDARDS  	  D-l
            D.I  Introduction ,	  D-l
            P..2  Construction Equipment  	  D-2
            D.3  Noise Standards for  Indoor  and Outdoor
                 Equipment for Home and  Office Use  	 D-10

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                         LIST OF FIGURES


                                                            page

Figure    1.   Construction Equipment Noise Ranges 	    11

          2.   Provisional Criteria Relating NPL to Commun-
              ity Noise Acceptability 	    17

          3.   A Summary of Noise Levels for Appliances Mea-
              sured at a Distance of 3 ft 	    31

          4.   Sound Pressure Levels of Various Refrigera-
              tors (Measured at 3 ft) 	    32

          5.   Schematic View of a Typical Room Air Condi-
              tioner 	    36

          6.   Sound Pressure Levels Prom Air Conditioner on
              High Cool and High Fan Settings (Measured at
              3 ft) 	    38

          7.   Sound Pressure Levels From Air Conditioner on
              Two Settings (Measured at 3 ft) 	    40

          8.   Graphic Level Recording and Octave Band
              Sound Pressure Levels of a Dishwasher 	    42

          9.   Sound Pressure Levels of Various Automatic
              Dishwashers During Wash Cycle (Measured at
              3 ft) 	    43

         10.   Sound Pressure Levels From Four Food-Waste
              Disposers (Measured at 3 ft) 	    46

         11.   Sound Pressure Levels of Canister Vacuum
              Cleaners Operating on Wood or Tile Floors
              (Measured at 3 ft) 	    48

         12.   Sound Pressure Levels of Two Upright Vacuum
              Cleaners (Measured at 3 ft)	    49

         13.   Time History of the Sound Pressure Level in
              the 250 Hz Octave Band for a Tank' Water
              Closet	    51
                              VI

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                   LIST  OF  FIGURES  (Continued)


                                                            page

Figure   14.  Time History  of Sound Pressure Level in 250
              Hz Octave  Band for a Flush Valve Water
              Closet 	    52

         15.  Range of Peak Octave Band Sound Pressure
              Levels in  Rooms with Tank Type Water Closets.    5^

         16.  Range of Peak Octave Band Sound Pressure
              Levels in  Rooms with Flush Valve Water
              Closets	    55

         17.  Range of Sound Levels in dB(A) Typical for
              Building Equipment at 3 ft 	    57

         18.  Cross-Section of a Typical Multistory Build-
              ing Showing Building Equipment 	    59

         19.  Range of Building Equipment Noise Levels to
              Which People  are Exposed 	    60

         20.  Construction  Site Geometry and Attenuation
              Contours for  a Stationary Population within
              Buildings  	    79

         21.  Percent of Households with Selected Noise-
              Producing Appliances and Tools	    97

         22.  Estimated Percent Distribution of Major
              Appliances by Income Level 	    98

         23.  Noise Profiles From Appliance for Typical
              •Households Per Week (at 3 ft) 	   105

         24.  Number of Building Construction Sites Pro-
              jected to the Year 2000 	   123

         25.  Projected Change in Exposure  to Construction
              Noise, Assuming No Change in  Noise Levels ...   126

         26.  Projected Change in Exposure  to Appliance
              Noise, Assuming No Change in  Noise Levels ...   128

         27.  Cost of Noise Control vs Noise Reduction  ....   172
                                 vii

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                 LIST OF FIGURES (Continued
                                                            page
Figure  A-l    Sound Pressure Levels for Various Appli-     A-39
through A-6l.   ances and Items of Construction Equipment..  thru
                                                            A-99

        B-l.   Linear and Area Distribution of Population
               in Municipalities (Based on Massachusetts
               and Pennsylvania Data) 	  B-ll
                              viii

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                         LIST OF TABLES


                                                            page

Table    I-a.  Typical Ranges of Noise Levels  at Construc-
               tion Sites With A 50 dB(,A)  Ambient Typical
               of Suburban Residential Areas	    19

         I-b.  Typical Ranges of Noise Levels  at.Construc-
               tion Sites :With A 70 dB(A)  Ambient Typical
               of Urban Areas	    20

          II.  Noisiest Equipment Types Operating at Con-
               struction Sites 	    22

         III.  Noise Pollution Levels in dB(A) of Construc-
               tion Sites, Various Equipment Quieting
               Strategies 	    24

          IV.  Immediate Abatement Potential of Construc-
               tion Equipment 	    26

           V.  Noise Control for Construction Equipment ...    28

          VI.  Sources of Appliance Noise 	    34

         VII.  Exposure of Building Occupants to the Noise
               of Building Equipment 	    58

        VIII.  Estimates of Magnitudes of Noise Effects ...    63

          IX.  Metropolitan Regions Considered in Construc-
               tion Noise Exposure Estimate; Statistics as
               of 1970 	    72

           X.  Annual Construction Activity - 1970  	    74

          XI.  Geographical Distribution of Working-Day
               Populations	    76

         XII.  Number of People Per Day Passing A Construc-
               tion Site	    77

        XIII.  Level of Annual Construction Activity ......    78
                              ix

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                   LIST OF TABLES (Continued)
                                                            page

Table    XIV.   Distribution of Stationary Observers  Rela-
               tive to Attenuation Contours 	    80

          XV.   Average and Peak Exposure Levels to Construc-
               tion Noise	    82

         XVI.   Estimated Annual Passings of Construction
               Sites -All Metropolitan Regions 	    84

        XVII.   Order of Magnitude Estimates of Yearly Dur-
               ation of Construction Noise Exposure  .......    86

       XVIII.   Order-of-Magnitude Estimates of Construction
               Noise Exposure in Millions of Person-Hours
               Per Week 	    92

         XIX.   Order-of-Magnitude Estimates of Impact of
               Primary and Secondary Exposure to Construc-
               tion Noise Expressed in Millions of Person-
               Hours Per Week 	    93

          XX.   Noncontrollable Household Noise Sources ....    95

         XXI.   Average Hours Per Day Spent on Household
               Work By 1296 Homemakers, According to Number
               of Children and Age of Youngest Child, Syra-
               cuse, New York Area, 1967-68 	   102

        XXII.   Appliance Usage Source Data 	   103

       XXIII.   Use of Noncontrollable Noise-Producing
               Appliances and Tools in Typical Households .   104

        XXIV.   Number of Individuals Exposed to Indicated
               Appliances	   107

         XXV.   Estimated Number of Individuals Exposed to
               Domestic Appliance Noise 	   108

        XXVI.   Sound Pressure Levels of Home Appliances and
               Building Equipment Adjusted for Location of
               Exposure	   109

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                   LIST OF TABLES  (Continued)
Table  XXVII,
      "XXVIII
         A-l

         A-2
                                             page

Order-of-Magnitude Estimates of the Extent
and Duration of Exposure to Building Equip-
ment .and Home Appliances ...................  110

Order-of-Ma'gnit'ude Estimates of Exposure to
Rome .Appliance and Building Equipment Noise
Expressed in Millions of Person-Hours Per
Week '..'..' ---- . . ......... ......... ...........  120
Use of Equipment at Construction Sites
Usage Factors of Equipment in Domestic
Housing Construction .......................  A-5
                               xi

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1.   INTRODUCTION
     As a society evolves technologically,  the  sources  of  noise
grow in number and kind.   Noise levels increase and the effects
of noise on society become increasingly severe.  Concomitantly,
society continually requires more machinery,  operating  at  higher
speeds with greater power output.  Aircraft,  for example,  have
continued to grow in number and noise level,  creating almost  in-
tolerable conditions for populations living,  working, and  playing
in the vicinity of airports.  Trucks and construction equipment
require increasingly powerful engines to enable a single operator
to move more goods, materials, or earth faster  and more economic-
ally.  The thunder of these engines not only  degrades the  quality
of life in our communities but also causes the  operators to incur
substantial levels of permanent hearing loss.  A profusion of ap-
pliances that provide the energy needed to do everything from
brushing our teeth and cooling our houses, to washing our dishes,
disposing of our garbage, and cutting our grass often generate
noise levels that interfere with conversation and disturb neigh-
bors.  Even the wilderness, once a refuge from hectic urban life,
is now disturbed by the noise of trail bikes, all-terrain vehic-
les, and snowmobiles.
     Given that noise is a serious environmental problem,  some
appropriate questions one might ask in seeking a comprehensive
noise-control objective are:  Precisely what are the sources of
noise pollution?  How many people are exposed to these  sources
and how are they affected?  What can be done to control the noise
output of offending sources?  This report attempts to answer
these questions for the specific categories of construction,
home appliances, and building equipment.

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 1.1  Source Characterization
     The two principal objectives in characterizing sources are
 (1) evaluating noise levels in quantitative terms that may be
 used to determine the impact on people and (2) obtaining the in-
 formation needed to assess the noise reduction that can be
 achieved.  Relating measurable aspects of sound to human response
 is difficult at best.  Such impact criteria as speech interfer-
 ence, sleep interruption, and annoyance depend not only on the
 physical nature of sound such as level, spectral content, and de-
 gree of fluctuation but also on the nonphysical aspects of noise
 such as the information content or implications of the sound.  A
 rattling piece of equipment is often annoying not because of the
 noise level but primarily because it indicates a malfunction re-
 quiring attention.
     Several attempts have been made to include various aspects
 of noise in a single number related to annoyance.  Most of these
methods try to account for the unequal sensitivity of the human
 hearing mechanisms  to different frequencies and some try to ac-
 count for fluctuations of level with time.  A single number which
accounts rather well for the human ear's relative insensitivity
 to low and very high frequency sound is the A-weighted scale.
This weighting has  been found to correlate about as well with
annoyance as other  indices [1]; it is quite widely accepted and
 can be read on a meter.   In this report, we use A-weighting [dB(A)l
to characterize noise insofar as impact evaluations are concerned.
     Noise spectra  are of far more use than single number ratings
for assessing the contribution from various components to total
noise levels.   Pure tones associated with integer multiples of
speeds of rotating  machinery often appear as  identifiable spec-
tral peaks.   Exhaust noise from an internal combustion engine

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typically contributes the dominant low-frequency component,
whereas engine structural radiation and turbocharger whine usually
generate the high-frequency levels.  Hence,  where possible,  we
provide noise spectra in octave or one-third octave bands.
     Once sources have been characterised, we evaluate the abate-
ment potential associated with each.  Our evaluation is based on
a somewhat broad analysis of the component contributions and to
a great extent on judgment developed from experience with similar
sources.  For example, prior work with internal combustion engines
enables us to estimate the benefit achievable from state-of-the-
art mufflers or engine enclosures.  We estimate our predictions
of achievable abatement potential to be within ±5 dB.  A more
accurate prediction of noise reduction would require detailed
diagnosis of contributions from each source component and imple-
mentation of experimental noise-control treatment.
     Because of the large number of sources evaluated  (see Sec.
2), we place much detailed information (e.g., a number of noise
spectra for sources whose impact is small) in Appendix A.  In-
cluded in Appendix B is the background to the development of im-
pact criteria and in Appendix D a discussion of existing  standards

1.2  Impact Evaluation
     We evaluate the impact of noise on people, using  two princi-
pal measures:  intensity and extent.  Clearly, it is important to
know the levels to which a person may be exposed and the  effects
of this exposure.  Thus, once the sources have been characterized
and the, relation of a listener to the source has been  postulated,
we estimate the physiological, psychological, and sociological
effects p.f the noise.  For example, permanent hearing  damge is
likely to occur for a significant percentage of the population

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exposed to levels of 90 dB(.A) for eight hours a day over an ex-
tended period of time.  If the exposure time is short (e.g., 15
minutes a day), the noise may or may not contribute to hearing
damage, but during exposure one cannot conduct an intelligible
conversation.  Exposure during evening hours to levels of noise
that exceed approximately 70 dB(A) will usually lengthen the time
one requires to go to sleep or will awaken someone who is already
asleep — especially if the noise is intermittent and the back-
ground level is low.
     The extent of noise impact is as important as the intensity in
assessing the magnitude of noise pollution since this measure
gives so.me perspective to the contribution from various sources.
A truly comprehensive assessment would involve a detailed social
survey with extensive noise measurements and statistically sig-
nificant samples from every stratum of society.   Such a program
would no doubt consume millions of dollars and several calendar
years.  Clearly, this approach is not feasible in the three-month
time period available for this study, nor would it represent an
entirely justifiable allocation of resources.  The goal of deter-
mining the impact of noise can be viewed only as an intermediate
step to solving the actual problem:   reducing the noise exposure
of our population.   Hence, an order-of-magnitude assessment of
impact is probably an adequate guide to the development of a noise-
abatement program.   What matters, for example, is that approxi-
mately six million workers on night  shifts and children under
four cannot sleep because of construction noise.  One's approach
to construction-noise abatement would probably not be different
if the figure were two million or ten million.  We therefore pro-
vide this impact evaluation,' not by  social survey, but by esti-
mating (1) the noise levels to which people are exposed,  (2:) the
effects of noise on these people, and (3)  the number of people

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exposed.  These estimates are based on measured values of eauip-
ment noise, data on human response to noise,  statistics of equip-
ment utilization, and statistics of population distributions.
The impact of construction, appliances, and building equipment  is
discussed in Sec. 3-

1.3  Industry Assessment
     To bring about control of environmental  noise,  the EPA must
have information not only about the technology of abatement but
also about the nature of the industry it may  be called upon to
influence.  An understanding of the pressures for and against
noise control is helpful in assessing the extent to  which an in-
dustry is likely to institute noise control measures on its own
and how the industry will be affected if it is compelled to pro-
duce quieter products.   For example, the principal impact of con-
struction noise, other than hearing-damage risk to operators (who
have been amazingly casual about their plight), is on the commun-
ity rather than the purchaser.  The community has been able to
exert very little influence on the purchaser  or the  manufacturer,
the result being that very little has been accomplished in quiet-
ing construction equipment.  For example, diesel-powered equipment
is sometimes advertised and sold without even mufflers.  A small
number of companies, however, have begun to produce  quiet equip-
ment; they attribute their recent success in  the marketplace to
certain local noise legislation and to the threat of such regula-
tions spreading to other communities.
     An example of the effects that noise regulations may have  on
business comes from the home appliance industry.  An air-
conditioner manufacturer has indicated that certain  marketplace
pressures inhibit him from implementing additional noise control
in bottom-of-the-line items.  He argues that  more noise control

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would increase the price of an item, thereby harming his competi-
tive position.  If all manufacturers were required to make their
products quieter (and therefore more costly), one could argue that
a segment of the population at lower income levels could no longer
afford air-conditioners and would be deprived of that comfort.
     By interviewing manufacturers of construction equipment,
home appliances, and building equipment, we obtained their views
of the relevance of noise control to their business.  We found a
substantial difference between the attitudes of people who manu-
facture construction equipment and those who manufacture appli-
ances.  The former, who find practically no marketplace demand
for quiet equipment, are faced with the prospect of a me'lange of
state and city ordinances;  they almost welcome "reasonable" fed-
eral standards.   The latter find an increasing marketplace demand
for quiet appliances and prefer not to see the implementation of
federal standards  or labeling requirements.  Chapter 4 of this re-
port contains an analysis of the pressures on industry to reduce
(or not to reduce)  noise levels, its response to these pressures,
its present achievements, and its potential.

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2.   SOURCE CHARACTERIZATION
2.1  Construction Equipment and Operation
     Construction has become a. major noise problem in many  cities
and towns.  The trend toward urban renewal and more high-rise
structures has created an almost perpetual din on city streets.
Equipment associated with construction projects is more numerous,
and the time span for construction at a given site has lengthened.
Residents very near a construction site may well plan on two years
of intolerable noise levels as a high-rise structure is being
built.
     In this section, we consider the construction noise problem
as it relates to residential and nonresidential buildings,  city
streets, and public works, because these kinds of project usually
take place in areas where the number of people likely to be ex-
posed is very high.  Heavy construction, such as highways and
civil works, has been omitted from our study because the vast
bulk of this activity occurs in thinly populated areas where  the
noise affects very few people.  We view construction as a pro-
cess that can be categorized according to type and that consists
of separate and distinct phases.

2.1.1  The construction process
     The basic unit of construction activity is the construction
site, which exists in both space and time.  The temporal dimen-
sion consists of various sequential phases which change the
character of the site's noise output as work progresses.  These
phases are discussed further below.  In the case of building con-
struction, the spatial character of the site is self-evident;  in
the case of sewers and roads, the extent of a site is taken,  for
reasons explained in Sec. 3.2, to be one standard city block or

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about 1/8 of a mile.   (That Is,  If a city reports  40  miles  of
sewer construction, we consider that project as  consisting  of
j20 separate sites.)
     Construction sites are typically classified in the fifteen
categories in which construction data is reported  by  the U.S.
Bureau of Census and  various state and municipal bodies. The
categories are:
     • Residential buildings:
          one- to four-family
          Five-family and larger
     • Nonresidential buildings:
          Office, bank, professional
          Hotel, motel, etc.
          Hospitals and other institutions
          Schools
          Public works buildings
          Industrial
          Parking garages
          Religious
          Recreational
          Store, mercantile
          Service, repair station
     • Municipal streets
     • Public works (e.g., sewers, water mains).
     For purposes of allocating construction effort among the
different types of sites, it it possible to group the nonresiden-
tial sites into four larger categories which are differentiated
by the cost of the average building in each category, as well as
by the distribution of effort among the various construction

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phases.  These four groups,  in order of decreasing average  cost
per building, are:
     • Office buildings, hospitals,  hotels
     • Schools, public works buildings
     • Industrial buildings, parking garages
     • Stores, service stations,  recreational buildings,  and
         religious  buildings.
     Construction is carried out  in  several reasonably discrete
steps, each of which has its own  mix of equipment and consequently
its own noise characteristics.  The  phases (some of which can be
subdivided) are:
     • Building Construction
       1.  a.  Clearing
           b.  Demolition
           c.  Site preparation
       2.  Excavation
       3.  Placing  foundations
       4.  a.  Frame erection
           b.  Floors and roof
           c.  Skin and windows
       5.  a.  Finishing
           b.  Cleanup
     • City Streets
       1.  Clearing
       2.  Removing old roadbed
       3.  Reconditioning old roadbed
       4.  Laying new subbase, paving
       5.  Finishing and cleanup

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     • Public Works
       1.  Clearing
       2.  Excavation
       3.  Compacting trench floor
       4.  Pipe installation, filling trench
       5.  Finishing and cleanup.
     Defining the construction phases as above allows us to ac- •
count for the variation in site noise output with time.  By inven-
torying the equipment which is to be found at each site in each
phase, we can derive a representative source level for each phase
by the process described below.

2.1.2  Equipment noise characteristics
     Despite the variety in type and size of construction equip-
ment, similarities in the dominant noise sources and in patterns
of operation permit one to assign all equipment to a very limited
number of categories.  These categories are described below and
are indicated in Pig. 1, together with corresponding noise level
data.  Corresponding spectra and the sources of this data are
given in Appendix A.

     Equipment Powered by Internal Combustion Engines
     The most prevalent noise source in construction equipment is
the: prime mover, i.e., the internal combustion engine (usually of
the diesel type) used to provide motive and/or operating power.
Engine-powered equipment may be categorized according to its mo-
bility and operating characteristics, as (1) earthmoving equip-
ment (highly mobile), (2) handling equipment (partly mobile), and
(3) stationary equipment.
     Earthmoving equipment includes excavating machinery (back-
hoes, bulldozers, shovels, front loaders, etc.) and highway
                               10

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NOISE LEVEL (clBA)AT 50 FT
60 70 80 90 100 110
w
u
z
MTERNAL COMBUSTION ENG
EQUIPMENT POWERED BY 1
EARTH MOVING
MATERIALS HArjDLING
STATIONARY 1
IMPACT
EQUIPMENT
OTHER
COMPACTERS (ROLLERS)
FRONT LOADERS
BACKHOES
TRACTORS
SCRAPERS, GRADERS
PAVERS
TRUCKS
CONCRETE MIXERS
CONCRETE PUMPS
CRANES (MOVABLE)
CRANES(DERRICK)
PUMPS
GENERATORS
COMPRESSORS
PNEUMATIC WRENCHES
JACK HAMMERS AND ROCK DRILLS
PILE DRIVERS (PEAKS)
VIBRATOR
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Note: Based on Limited Available Data Samples
FIG.  1.   CONSTRUCTION EQUIPMENT NOISE  RANGES.
                                  11

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building equipment (compactors, scrapers, graders, pavers,  etc.).
Internal combustion engines are used for propulsion (either on
wheels or tracks) and for powering working mechanisms (buckets,
arms, trenchers, etc.)-   Engine power varies from about 50  hp to
over 600 hp.  Engine noise typically predominates, with exhaust
noise usually being most significant and with inlet noise and
structural noise being of secondary importance.  Other sources
of noise in this equipment include the mechanical and hydraulic
transmission and actuation systems, and cooling fans (often very
significant).  Typical operating cycles may involve one or  two
minutes of full-power operation, followed by three or four  minutes
at lower power.
     Noise levels at 50 ft from earthmoving equipment range from
about 73 to 96 dB(A).  The greatest and most direct potential for
noise abatement here lies in quieting the engine by use of  im-
proved mufflers.
     Engine-powered materials-handling equipment such as cranes,
derricks, concrete mixers, and concrete pumps, is used in a more-
or-less fixed location;  mobility of this equipment over the ground
is not part of its major work cycle.  Although noise from the
working process (such as the clanking of aggregate in the concrete
mixing bin) often is the most "identifiable" noise component, the
dominant source of noise generally is the prime mover.  Noise
levels at 50 ft range from about 75 to 90 dB(A).  The greatest
potential abatement for noise again lies in engine quieting, with
treatment of power transmission and working mechanisms being of
secondary importance.
     Stationary equipment, such as pumps, electric power gener-
ators and air compressors, generally runs continuously at
relatively constant power and speed.  Noise levels at 50 ft range
                               12

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from about 70 to 80 dB(A), with pumps typically at  the  low  end  of
this range.  Stationary equipment, because of its  fixed location
and constant speed and/or load operation,  may be quieted more
easily than mobile equipment; engine mufflers can  be more effec-
tive, and use of enclosures becomes feasible.  [In fact, noise
from some air compressors, has already been reduced by  about
10 dB(A) by use of appropriate enclosures.]
     The greatest near-term abatement potential for all current
equipment powered by internal combustion engines lies in the use
of better exhaust mufflers, intake silencers, and  engine enclo-
sures (in conjunction with appropriate cooling system and fan de-
sign).  Reductions of 5 to 10 dB(A) appear to be achievable,
usually without great difficulty.   Practical long-term  abatement
[of about 15 to 20 dB(A)] can probably be  achieved by basic engine
design changes.  Of course, replacement of the internal combus-
tion engine by a quieter prime mover, such as a gas turbine or
electric motor, would eliminate the reciprocating-engine noise
source altogether.

     Impact Equipment and Tools
     Conventional pile drivers are either steam-powered or  diesel-
powered; in both types, the impact of the hammer dropping onto  the
pile is the dominant noise component.  With steam drivers,  noise
is also generated by the power supply (a boiler) and the release
of steam at the head; with diesel drivers, noise is also gener-
ated by the combustion explosion that actuates the hammer.   Noise
levels are difficult to measure or standardize, because they are
affected by pile type and length, but peak levels  tend  to be about
100 dB(A) (or higher) at 50 ft.
                               13

-------
     Impact-noise is absent in the so-called "sonic" (or vibra-
tory) pile drivers.   These do not use a drop hammer, but vibrate
the pile at resonance.   The noise associated with pile vibrations
typically occurs around 150 Hz and is barely audible.   The power
source, which generally consists of two gasoline engines, is  the
primary noise source.
     Abatement can be accomplished best by substituting use of a
sonic pile driver for an impact machine where possible.  (Unfor-
tunately, sonic pile drivers are useful only for some soils.)
Impact noise reduction at the source generally is very difficult.
Substitution of nonimpact tools offers the best practical abate-
ment potential; otherwise, reductions of perhaps 5 dB(A) may  be
obtained by use of enclosures.
     Most impact tools, such as jack hammers, pavement breakers,
and rock drills are  pneumatically powered, but there are also
hydraulic and electric models.  The dominant sources of noise in
pneumatic tools are  the high-pressure exhaust and the impact  of
the tool bit against the work.  Noise levels at 50 ft typically
range from 80 to 97  dB(A).
     An exhaust muffler on the compressed air exhaust can lower
noise levels from the exhaust by up to about 10 dB(A).  Pneumatic
exhaust noise, of course, is absent in hydraulic or electric  im-
pact tools.  Reduction of the impact noise from within a tool can
be accomplished by means of an external jacket, which can contri-
bute perhaps a 5 dB(A) reduction.  Reduction of the noise due to
impact between the tool and material being worked upon generally
is difficult and requires acoustic barriers enclosing the work
area and its immediate vicinity.  Depending on the impacted struc-
tures, such barriers may reduce noise by 3 to 10 dB(A).
                               lit

-------
     Small hand-held pneumatic tools,  such as  pneumatic wrenches,
generate noise of levels between 84  and 88 dB(A)  at  50  ft.   The
exhaust and the impact are the dominant noise  sources.  Because
of the obvious weight and size limitations to  which  hand  tools
are subject, only small and light mufflers can be used  with  them,
limiting the achievable noise reduction to 5 dB(A) at best.   The
best practical means for reducing the  noise from impact tools
consists of using other types of tools to accomplish the  same
functions.

2.1.3  Site noise characteristics
     To characterize the noisiness - i.e., the average  noise an-
noyance potential — of the various types of construction  sites
during each phase of construction, a Noise Pollution Level (NPL)
was calculated for each type of site and each construction phase.
The NPL used here was taken as the same measure that was  used for
similar evaluation of traffic noise [2].  The NPL (in dB) is de-
fined as the sum of the A-weighted average sound pressure level
and 2.56 times the standard deviation of the A-weighted sound
pressure level*; thus, NPL accounts for the effect of steady
noise, plus the annoyance due to fluctuations.
     Although a thorough study relating NPL to subjective descrip-
tors of annoyance (e.g., acceptable, unacceptable) has not been
accomplished, a provisional interpretation of NPL in such terms
can be suggested.  On the basis of an evaluation of domestic and
*A-weighting refers to a standard weighting of the various fre-
 quency components, approximating the behavior of human hearing.
 The average sound pressure level is computed on the basis of the
 time-average root-mean-square sound pressure, whereas the stand-
 ard deviation is calculated from the time-variation of the dB(A)
 values.
                               15

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foreign social surveys and psycho-acoustic studies, the Depart-

ment of Housing and Urban Development has adopted a set of

"guideline criteria" [3] for outdoor noise levels in residential

areas as shown in Fig. 2 [4J.  According to this chart, the com-
munity noise situation is evaluated by comparing a measured dis-

tribution of A-weighted levels with the criteria curves.   The

situation is categorized by the region of least desirability

penetrated by the actual noise distribution.   Since this  criterian
is based on level distributions, the boundaries between regions

of acceptability may be defined in terms of the NPL.  Thus, the
following descriptors of NPL values may be used in interpreting

the site noise NPL levels used in the remainder of this report.
Clearly Acceptable:  The noise exposure
is such that both the indoor and out-
door environments are pleasant.

Normally Acceptable:   The noise exposure
is great enough to be of some concern
but common building constructions will
make the indoor environment acceptable,
even for sleeping quarters, and the out-
door environment will be reasonably
pleasant for recreation and play.

Normally Unacceptable:  The noise ex-
posure is significantly more severe so
that unusual and costly building con-
structions are necessary to ensure some
tranquility indoors,  and barriers must
be erected between the site and promi-
nent noise sources to make the outdoor
environment tolerable.

Clearly Unacceptable;  The noise expos-
ure at the site is so severe that the
construction costs to make the indoor
environment acceptable would be prohibi-
tive and the outdoor environment would
still be intolerable.
NPL less than 62 dB
NPL between 62 and
            7^ dB
NPL between 7** and
            88 dB
NPL greater than
            88 dB
                               16

-------
loo
                                             CLEARLY
                                          UNACCEPTABLE
                           NORMALLY
                          UNACCEPTABLE
               NORMALLY
              ACCEPTABLE
        CLEARLY
       ACCEPTABLE
                                                            50%
   FIG.  2
                         60         70

                    A-WEIGHTED  LEVEL (dBA)
PROVISIONAL CRITERIA  RELATING NPL  TO COMMUNITY
NOISE ACCEPTABILITY
                            17

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We must emphasize that these criteria have not been officially or
unofficially adopted by HUD or any other government agency.  They
are presented here solely to enable the reader to interpret NPL
values computed in this report.
     The aforementioned averages of noise annoyance potential
were calculated on the basis of information obtained on (1) the
number of each item of equipment typically present at a site (in
a given phase), (2) the length of the duty cycles of this equip-
ment, and (3) the average noise levels during operation.   For
purposes of site characterization, the noisiest piece of equip-
ment was assumed to be located at 50 ft from an observer, and
all other equipment was assumed to be located at 200 ft from the
observer;  ambient noise, of levels depending on the surroundings
of the site, was taken to be present in addition to the equipment
noise.  (Note that pile driver noise was not included in the NPL
calculations, because its repetitive impact character makes its
intrusion characteristics different from the more continuous
noises for which the NPL concept was developed.)  Clearly, this
construction noise model is not entirely realistic; however, it
may be expected to fulfill its intended purposes — that of yield-
ing at least a relative measure of the noise annoyance associated
with each type of site and phase for the most adverse conditions
likely to be associated with each phase.
     Table I shows NPLs calculated for each of five phases for
each of four types of construction.  For residential housing and
public works construction, two NPL values are given in the table;
one pertains to a noisy [70 dB(A)] background characteristic of
urban conditions, the other to relatively quiet [50 dB(A)] am-
bient conditions found in suburban environments.  As one may ex-
pect, the values indicated in the table reflect the fact that a
given intruding noise is more annoying if it occurs in a quieter
environment.
                               18

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          TABLE I-a.  TYPICAL RANGES OF NOISE LEVELS AT CONSTRUCTION SITES WITH A

                   50 dB(A) AMBIENT TYPICAL OF SUBURBAN RESIDENTIAL AREAS
             Domesti c
              Housing
     Office Build-
      ing,  Hotel ,
       Hospital
    School  , Public
         Works
              I
II
I
II
               Industrial
            Parking Garage,
               Reli gious ,
              Amusement &
              Recreations,
             Store,  Service
                Station
I
II
                         Public Works
                        Roads & High-
                        ways , Sewers,
                         and Trenches
I
II
Ground
Clearing

(-•Excavation


Foundations


Erection


Finishing

83
8
103
88
8
109
81
10
107
81
10
107
88
7
106
83
15
122
75
14
111
81
17
124
65
9
87
72
12
104
84
7
101
89
6
105
78
3
84
87
6
99
89
7
107
84
16
123
79
2
85
78
3
86
75
2
79
75
8
97
84
9
106
89
6
105
77
4
87
84
9
107
89
7
105
83
16
124
71
2
77
77
5
90
72
7
91
74
10
100
84
8
103
88
7
106
88
8
108
79
9
103
84
7
101
84
8
104
78
3
86
88
8
108
78
11
108
84
8
104
                                                                       Energy Average dB(A)
                                                                       Standard Deviation
                                                                       NPL


                                                                       Energy Average dB(A)
                                                                       Standard Deviation
                                                                       NPL


                                                                       Energy Average dB(A)
                                                                       Standard Deviation
                                                                       NPL


                                                                       Energy Average dB(A)
                                                                       Standard Deviation
                                                                       NPL


                                                                       Energy Average dB(A)
                                                                       Standard Deviation
                                                                       NPL
 I  — All pertinent equipment  present  at  site.

II  — Minimum required equipment  present  at  site

-------
          TABLE 1-b.
TYPICAL RANGES OF NOISE LEVELS  AT  CONSTRUCTION  SITES  WITH  A
    70  dB(A)  AMBIENT  TYPICAL  OF  URBAN AREAS

Ground
Clearing
Excavation
Foundations
Erection
Finishing
Domestic
Housing
I II
84 83
6 8
100 103
88 76
7 5
106 88
81 81
7 7
99 100
82 71
6 1
97 75
88 74
7 4
106 84
Office Build-
ing, Hotel ,
Hospital
School, Public
Works
I II
84 84
6 8
99 103
89 79
6 2
104 85
78 78
3 2
85 85
85 76
5 1
97 79
89 76
6 4
104 86
Industrial ,
Parking Garage,
Rel igious ,
Amusement &
Recreations,
Store, Service
Station
I II
84 87
6 8
101 103
89 74
7 1
106 77
78 78
3 3
85 85
85 74
7 2
103 80
89 75
6 3
104 84
Public Works
Roads & High-
ways, Sewers,
and Trenches
I II
84 84
6 7
100 101
89 79
6 2
105 85
88 88
8 8
108 108
79 79
I 4
88 88
84 84
6 6
100 100

Energy Average dB(A)
Standard Deviation
NPL
Energy Average dB(A)
Standard Deviation
NPL
Energy Average dB(A)
Standard Deviation
NPL
Energy Average dB(A)
Standard Deviation
NPL
Energy Average dB(A)
Standard Deviation
NPL
 I  — All pertinent equipment present at site.
II  —Minimum required equipment  present at  site.

-------
     The NPL values shown in Table I obviously depend on the  pre-
viously described model of site noise.   For this model,  the aver-
age sound pressure level depends strongly on the one or  two noisi-
est pieces of equipment, whereas the standard deviation  depends
largely on the numbers and duty cycles  of the less noisy equip-
ment and on the ambient noise level.
     As evident from Table I, in building construction,  the in-
itial ground clearing and excavation phases tend to be the noisi-
est, the subsequent foundation and erection phases tend  to be
somewhat less noisy, and the final finishing phase again tends  to
be relatively noisy.  In public works construction, on the other
hand, NPLs are more nearly the same for all phases, except that
the erection phase tends to be less noisy.
     Table II lists the two noisiest types of equipment  for  each
site type and phase, together with the average A-weighted noise
levels (at 50 ft) for this equipment.  Inspection of this table
indicates that rock drills, which typically are the noisiest
equipment, are prevalent in the excavation and finishing phases;
trucks, on the other hand, are somewhat less noisy than rock
drills or similar equipment but are present in nearly all phases.

     Effect of Equipment Quieting
     To assess the effect of some quieting strategies on the pre-
viously described site noise model, we recalculated the NPL  for
three "strategies" for each type of site and each phase:
Strategy 1:
    • Only the noisiest piece of equipment being quieted by 10
     dB(A), with this equipment remaining at the previously
     specified 50 ft distance from the observer.
                               21

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             TABLE  II.  NOISIEST EQUIPMENT TYPES OPERATING AT CONSTRUCTION SITES*
rv>
fv>
                                               Construction  Ty p e
                    Domestic Housing   Office  Bldgs.        Industrial
        Ground
          Clearing
             Truck
             Scraper
           (91)
           (88)
     to
     to
     -M
     O
Excavation   Rock Drill (98)
             Truck      (91)

Foundations  Concrete Mixer
                        (85)
             Pneumatic Tools
                        (85)
Truck
Scraper
(91)
(88)
Truck
Scraper
(91)
(88)
                                       Rock Drill  (98)   Rock Drill  (98)
                                       Truck       (91)   Truck       (91)
                  Concrete Mixer
                             (85)
                  Concrete Mixer
                             (85)
                                                                     Public  Works
Truck
Scraoer
(9D
(88)
                                                      Rock Drill (98)
                                                      Truck      (91)
                                       Jack  Hammer(88)   Jack Hammer(88)   Truck
                         Scraoer
                                                                 (91)
     in
     c
     o
Erection
Concrete Mixer
           (85)
Pneumatic Tools
           (85)
Derrick Crane     Derrick Crane     Paver      (89)
           (88)              (88)
Jack Hammer(88)   Jack Hammer(88)   Scraper    (88)
       Finishing
             Rock Drill (98)
             Truck      (91)
                  Rock Drill (98)
                  Truck      (91)
                  Rock Drill (98)   Truck
                  Truck      (91)   Paver
                                    (9D
                                    (89)
       *Numbers in parentheses represent typical dB(A) levels  at  50  ft.  See Table I for
        definition of construction types.

-------
Strategy 2:
   • Only the noisiest piece of equipment being quieted by 10
     dB(A)j with this equipment moved to 200 ft and with the
     next noisiest equipment (unquieted) moved to 50 ft from
     the observer position
Strategy A:
   • All items of equipment quieted by 10 dB(A).
     The results of these calculations are shown in Table III,
together with the NPL values previously obtained without any
quieting (Strategy 0).  It appears that quieting only the noisi-
est piece of equipment generally reduces the site NPL relatively
little, if other types of equipment can also operate near the
observer (compare Strategies 0 and 2).  On the other hand, quiet-
ing the noisiest equipment and letting no others operate near the
observer may result in significant reductions (compare Strategies
0 and 1).  Of course, quieting all equipment (Strategy A) results
in1the lowest NPL values; however, these values are often only
slightly lower than those obtained by quieting only the- noisiest
item (Strategy 1).
     The site noise model used here initially assumes the noisiest
equipment to be located nearest the observer.  It can happen that
quieting the noisiest equipment, moving it away from the observer,
and moving the second noisiest equipment near the observer
(Strategy 2) results in an-increase in the NPL, if the second
noisiest equipment is usedjmore frequently than the noisiest.
This peculiarity of the noise model, where equipment quieting
seemingly increases the noise, is evident at * several places in  "...
Table III.                                                       :
                               23

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                TABLE  III.   NOISE  POLLUTION  LEVELS  IN  dB(A)  OF  CONSTRUCTION SITES,

                             VARIOUS EQUIPMENT QUIETING  STRATEGIES*
70
(D
-a
O
-5
d-
ro

a>
VI
a
JC
o_
c
o
•4-J
O
1 Constri

Ambient
Quieting
Strategy**
Ground
Clearing
Excavation
Foundation
Erection
Finishing
Domestic Housing
Urban
0 1 2 A
100 88 98 85
106 93 109 92
99 81 81 81
97 82 88 81
106 93 99 92
Rural
0 1 2 A
103 91 101 9^
109 93 HI 100
107 86 83 96
107 105 102 93
106 93 99 95
Office
Building
Urban
0 1 2 A
99 86 96 85
104 91 105 91
85 80 94 76
97 84 85 85
104 91 98 92
Industrial
Urban
0 1 2 A
101 87 97 85
106 92 103 91
85 82 98 76
103 88 84 86
104 91 97 89
Public Works
Urban
0 1 2 A
100 84 87 85
105 91 98 92
108 87 96 90
88 81 89 77
100 89 94 85
Rural
0 1 2 A
103 87 91 91
106 92 99 95
108 89 96 99
103 89 90 84
101 88 95 92
                                                                                               10
                                                                                               ro
                                                                                               CO
                                                                                               O
                                                                                               CO
                                                                                               n>
                                                                                               EU
           * See text for site noise model;  see  Table  I  for construction type and ambient
             noise definitions.

          ** 0 — No quieting

             1 — Noisiest equipment, at  50  ft  from observer,  quieted by 10 dB(A).

             2 — Noisiest equipment quieted  by 10  dB(A)  and moved to 200 ft from observer;
                 second-noisiest equipment  (not  quieted) moved to 50 ft from observer.

             A - All equipment quieted by 10 dB(A).
QJ
3
CL
CU
13
O

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     Other Means for Site Noise Control
     The NFL generated by a construction site also may be  reduced
by means other than quieting the equipment:
   •  Replacement of individual operations and techniques by less
     noisy ones - e.g., using welding instead of riveting, mix-
     ing concrete offsite instead of onsite,  and employing pre-
     fabricated structures instead of assembling them on  site.
   •  Selecting the quietest of alternate items of equipment —
     e.g., electric instead of diesel-powered equipment,  hydraulic
     tools instead of pneumatic impact tools.
   •  Scheduling of equipment operations to keep average levels
     low, to have noisiest operations coincide with times  of
     highest ambient levels, and to keep noise levels relatively
     uniform in time; also, turning off idling equipment.
   •  Keeping noisy equipment as far as possible from site bound-
     aries.
   •  Providing enclosures for stationary items of equipment and
     barriers around particularly noisy areas on the site  or
     around the entire site.

     Equipment Noise Reduction Potential
     Table IV lists the present average noise levels in dB(A) for
the various types of construction equipment discussed previously;
also  listed are the noise levels expected to be achievable in a
relatively short time, with limited cost and performance  penal-
ties.  In addition, the table shows the most significant  noise
sources for each type of equipment and assigns a numerical "usage"
factor to each item, on the basis of which one can assess the
significance of quieting of the various individual items.   Prom
                               25

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            TABLE  IV.   IMMEDIATE  ABATEMENT POTENTIAL OF

                       CONSTRUCTION  EQUIPMENT
      Equipment
                          in
Noise  Level
dB(A)  at 50
Present

                    ft
                                        Feasible
                                        Control1
Important
  Noise
 Sources2
                                         Usage
Earthmoving
  front loader          79
  backhoes               &5
  dozers                 80
  tractors               80
  scrapers               88
  graders                85
  truck                  91
  paver                  89

Materials Handling
  concrete  mixer        85
  concrete  pump         82
  crane                  83
  derrick                88

Stationary
  pumps                  76
  generators             78
  compressors           81

Impact
  pile drivers         101
  jack ha mers          88
  rock drills           98
  pneumatic tools       86

Other
  saws                   78
  vibrator               76
                 75
                 75
                 75
                 75
                 80
                 75
                 75
                 80


                 75
                 75
                 75
                 75


                 75
                 75
                 75


                 95
                 75
                 80
                 80


                 75
                 75
E
E
E
E
E
E
E
E
C
C
C
C
C
C
C
D
P
P
P
P
P
P
F
P
I
I
I
I
I
I
I
I
H
H
H
W
W
W
T

.4
.16
.4
.4
.4
.08
.4
.1
                     E  C P W  T     .4
                     E  C H          .4
                     E  C P I  T     .16
                     E  C P I  T     .16


                     E  C          1.0
                     E  C          1.0
                     E  C H I      1.0


                     W  P E          .04
                     P  W E C        .1
                     W  E P          .04
                     P  W E C        .16


                     W               .04
                     W  E C          .4
          Notes:
             Estimated levels obtainable by selecting quieter procedures or
             machines and Implementing noise control features requiring no

             major redesign or extreme cost.
          2.  In order of Importance:

             T  Power Transmission System,
               Gearing

             C  Engine Casing

             E  Engine Exhaust

             P  Pneumatic Exhaust
                ? Cooling Pan


                W Tool-Work Interaction

                H Hydraulics

                I Engine Intake
             Percentage of time equipment Is operating at noisiest mode In

             most used phase on site.
                                  26

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this table, one may determine that control of engine noise,  and
particularly of engine exhaust noise,  will affect many items of
equipment with high usage factors and  thus should be given hip;h
priority.
     Table V presents a brief listing  of the noise control tech-
niques applicable to the sources indicated in Table IV, together
with an estimate of the noise reductions that may readily be
achieved by means of these techniques.

2.2  Home Appliances
     The use of convenient and sometimes necessary appliances
constitutes a growing noise problem within the home.  Almost with-
out exception, appliances could be significantly quieter.  How-
ever, manufacturers offer three primary arguments for opnosiner,
quieter redesign; they believe
    • that the public associates the noise generated by a device
     with its power;
    • that quieter appliances would be marketed at a price dis-
     advantage and  since the public has not objected  to noise,
     that  the public,  in general, is  satisfied;
    • that  since appliances are generally  controlled by the  oper-
     ator,  the option, as with air conditioners,  "to  have quiet
     or  to  be cool" is "option enough".
Yet, in  keeping with  the public's growing awareness of noise,
many appliances are advertised as being "noiseless",  "quiet",
"vibration-free".
     Although many  manufacturers  have made  detailed acoustic mea-
surements  of the noise output of  their  appliances,  very  little
data has been reported in the open literature.   Some  of  the
                                27

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        TABLE V.   NOISE  CONTROL  FOR  CONSTRUCTION  EQUIPMENT
     Source
Engine
  exhaust
  casing

  fan (cooling)


  intake
Transmission

Hydraulics

Exhaust
  (pneumatic)
Tool-Work
  interaction
   Control  Techniques

improved muffler
improved design of block
enclosure
redesign
silencers,  ducts and
mufflers
silencers
redesign, new materials
enclosure
redesign, new materials
enclosure

muffler

enclosure
change in principle
   Probable  Noise
Reduction in dB(A)*
         10
          2
         10
          5

          5
          5
          7
          7
          7
         10

        5-10

        7-20
       10-30
*Note that noise1 reductions are not additive.  Incremental re-
 ductions can be realized only by simultaneous quieting of all
 sources of equal strength.
                               28

-------
literature (especially "nonacoustic" reporting)  presents Insuf-
ficient information to enable utilization of the reported mea-
surements in this study.   For example, in one report [5], the
noise levels are described as being "recorded at operator's or
housewife's normal ear distance"; for those appliances not re-
quiring continual operation, the distance from the exposed person
to the appliance is not specified.  In other examples drawn from
newspapers, trade journals, and magazines measurements are not
qualified as to distance  from the source, type of instrumentation,
and weighting network (if any) that was used.  In the following
sections, only the literature found to be well-documented and
considered accurate will  be used in appropriate  discussions.

2.2.1  Measurements
     Because of the scarcity of reliable data, we measured the
noise from thirty types of home appliances and eleven types of
home shop tools.  Sound levels were measured in dB(A) at a dis-
tance of 3 ft from the appliance and a height of 5 ft; this
measurement position approximates the location of the operator's
ear for those appliances  requiring an operator.   For those appli-
ances not requiring an operator, this position represents noise
levels in the vicinity of the appliance.  Noise levels in the
reverberant field of the  room in which the appliance is being
operated may be on the order of 2 to 3 dB(A) less than the mea-
surement at 3 ft.                                 '
     Noise levels in adjacent rooms with the interconnecting door
open may be as much as 10 dB(A) less than the levels at 3 ft or
as much as several dB(A)  greater than the 3 ft levels, depending
upon the details of the installation.  For the appliances that
are used near the ear (e.g., an electric-shaver), the noise level
at the ear may be as much as 10 dB(A) greater than the 3 ft mea-
                               29

-------
 surenents.   Figure 3 summarizes the noise measurements  made  by
 jtJN and some of those reported in the  literature.   Each point
 represents  a single measurement.   Several measurements  are -riven
 for a single appliance that  operates in different  modes.  The
 solid circles  represent  noise  levels generated  by  American appli-
 ancies;  foreign brands are represented by the squares.   Problems
 arise in evaluating this  data  because  the appliances  were manu-
 factured in different years  by different  companies, were scat-
 tered through  the  lines  offered by  the manufacturers, and may be
 providing different features.   For  example, a recently  built
 refrigerator may be frost-free and  may have special devices  such
 as  ice makers;  therefore  it  may generate  more noise than earlier
 refrigerators.  Figure 4  presents octave  band spectra for refrig-
 erators  that were manufactured through  1958 [£] and in  1965,
 1967, and 1970  [7].   Noise generated by this sample of  refriger-
 ators demonstrates  the problem of data  comparison:  the unit that
 was old  in  1958 was  the noisiest, while the 1970 unit was second
 noisiest.   The quietest refrigerator is the 1965 model.  However,
 there is  considerable  difference between  the physical size of the
 units, and  the newer  models  incorporate such features automatic
 defrost,  ice-cube maker, water  dispenser, and humidified compart-
 ment .

 2.2.2  Noise abatement potential
     The thirty appliances and  eleven shop tools surveyed exhib-
 ited no apparent acoustical problems that could not be abated
 through the diligent application of noise control technology.
 Achieving a cost-effective solution that can be incorporated into
the design of an appliance is more difficult but still possible.
Standard noise control techniques are readily available; wrapping,
damping, flexible connections,  vibration isolation, better
                               30

-------
                             A-WEIGHTED SOUND LEVELS AT 3 FT





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 FREEZER
 REFRIGERATOR
 HEATER, ELECTRIC
 HAIR CLIPPER
 TOOTHBRUSH, ELECTRIC
 HUMIDIFIER
 FAN
 DEHUMIDIFIER
 CLOTHES DRYER
 AIR CONDITIONER
 SHAVER, ELECTRIC
 WATER FAUCET
 HAIR DRYER
 CLOTHES WASHER
 WATER CLOSET
 DISHWASHER
 CAN OPENER, ELECTRIC
 FOOD MIXER
 KNIFE, ELECTRIC
 KNIFE SHARPENER, ELECTRIC
 SEWING MACHINE
 ORAL LAVAGE
 VACUUM CLEANER
 FOOD BLENDER
 COFFEE MILL
 FOOD WASTE DISPOSER
 EDGER AND TRIMMER
 HOME SHOP TOOLS
 HEDGE CLIPPERS
 LAWN MOWER, ELECTRIC

FIG.  3.   A SUMMARY OF NOISE LEVELS FOR APPLIANCES  MEASURED AT
         A DISTANCE OF 3 FT.
                               31

-------
80
                       MANUFACTURED
                                   IN
63     125     250    500
    OCTAVE BAND CENTER FREQUENCY  IN  Hz
                                                    4000   8000
FIG  4   SOUND PRESSURE LEVELS  OF  VARIOUS REFRIGERATORS
         (MEASURED AT 3 ft)


-------
balance, and smoother mechanical connections.   Since many appli-
ances have similar mechanisms, noise control techniques used on
one appliance can often be applied to another.
     After reviewing the operating characteristics and mechanical
properties of appliances, we ranked the noise  sources in order
of their contribution to the total noise generated by an appli-
ance (see Table VI).  Definitive measurements  are not available
to enable a quantitative breakdown of the contribution of in-
dividual components.  However, in general, motors, fans, knives
(or other cutting blades), and air flow are the most frequent
sources of noise.  Noise radiated from the casing or panels of
the appliances and noise radiated from walls,  floors, cabinets,
sinks (set into vibration by solid structural  connections)  are
also of major importance.
     We review here in some detail the noise generating mechanisms
of several appliances that have high enough noise levels and ex-
posure time to be considered annoying.  Included in this review
are air conditioners, dishwashers, food waste  disposers, vacuum
cleaners, and toilets.  Other appliances are discussed in Appen-
dix A.

     Boom Air Conditioners
     Figure 5 is a schematic view of a typical room air condi-
tioner.  Basically, warm air in the room or from outside is drawn
through a dust filter, blown across cold evaporator coils and
distributed back into the room.  Fluid in the  evaporator, heated
by this action, flows to the condenser coils.   Outside air is
blown across these coils by the propeller fan.   The fluid is then
compressed and flows back to the evaporator.
                               33

-------
                TABLE VI.   SOURCES OF APPLIANCE  NOISE
*-                  co
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-------
                        TABLE  VI  (continued)
                             -                 <"               O)
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                    O.i—    c   (/)          fll CO   L.   .—   i-i   q>    O
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                             -£3   <_)             -t->               s-    re
    Appliance                
-------
      COMPRESSOR

           BYPASS
         BULKHEAD

   COLD EVAPORATOR
OUTDOOR
  AIR
                                    CONDENSER
                                    DISCHARGE
                                       AIR
                         t     t     I
                          COOLED
              WARM
                              ROOM  AIR
                                                      CONDENSER
                             MOTOR

                             BLOWER

                             FILTER
FIG.  5.   SCHEMATIC  VIEW  OF  A  TYPICAL  ROQM  AIR  CONDITIONER
                               36

-------
     The major sources of noise in this process are the motor,
the blower (evaporator fan), the propeller fan (condenser fan),
the compressor, and the air flow across the evaporator coils.   In
addition, panels of the housing radiate noise, as does the struc-
ture upon which the air conditioning unit is mounted.   The char-
acter of this noise is complex, consisting of pure tones, pulsat-
ing sounds, intermittent clicks, buzzes and rattles, all super-
imposed on broadband noise [5].  The tonal components  and broad-
band noise represent the primary noises that require noise con-
trol treatment; for the most part, buzzes and rattles  (often
caused by loose parts), intermittent clicks (caused by spring
activated thermostat controls and relays), and pulsating noises
(generated by the capillary tube and evaporator valves) have been
controlled in current models so that theyr do not dominate the
total noise level.
     Pure tones may be generated by (1) the motor at multiples of
the rotation speed, (2) the compressor at multiples of the pump-
ing fundamental frequency (the speed in revolutions per second
times the number of pumping .cycles per revolution), and (3) the
propeller fan at blade-passage frequency  (the speed in revolutions
per second times the number of blades).  Whether or not these pure
tones appear in the spectrum heard indoors depends upon the struc-
tural connections between the components and the enclosure panels
as well as on connections to supporting structures.  In Pig. 6,
noise levels measured on a particular unit with the fan on high
speed, with and without the compressor, illustrate this concept;
the increase in the one-third octave band centered at 63 Hz is
due to a lack of sufficient vibration isolation of the compressor
from its case and/or Insufficient isolation of the casing from
the wall supporting it.
                               37

-------
  80
                          HIGH COOL
                          HIGH FAN
           63     125     250    500    1000    2000    4000
          ONE-THIRD OCTAVE BAND  CENTER FREQUENCY  (Hz)
                                                        8000
FIG.
6.   SOUND  "P.rSSURE LEVELS FROM AIR CONDITIONER ON
                                                     HIGH COO
         AND
        HIGH  FAN SETTINGS (MEASURED AT  3  ft)


-------
     Broadband noise is generated by the blower,  the flow of air
through the evaporator coils,  and the deflection  of the air into
the room.  Often the blower can operate at several speeds;  the
slower the speed, the lower the noise level from  both the blower
and the air flow (see Pig.  7).
     Noise control means that  can be applied to,motor and com-
pressor noise include better vibration isolation  of the motor ana
fans from the housing through  use of rubber or neoprene mounts.
Compressors, usually hermetically-sealed, can be  mounted on
springs internally, and on rubber or neoprene pads externally.
A more thorough isolation of the motor, fans, and compressor from
the casing and of the complete unit from its support could result
in a noise reduction of about  5 dB in the low-frequency region
controlled by tonal sounds from these components.
     The broadband noise generated by the centrifugal blower and
the air flow can be reduced by
  '• reducing the air velocity by using the low-speed fan (if
     maximum cool is not required);
   • reducing the air velocity by increasing the  area of the
     evaporator coils (perhaps increasing the total size of the
     unit);
   • incorporating sound absorbing material, such as open-cell
     polyurethane foam,;between the evaporator coils and the de-
     flection grids and in the duct passage between the blower
     and the evaporator coils  and the blower and  the dust filter;
     and
   • tightening the gasketing system to eliminate rattles.
Broadband noise can be reduced by 10 to 15 dB through effective
use of these techniques.  Coupled with more effective isolation
                               39

-------
63     125     250    500    1000    2000    4000
 ONE-THIRD OCTAVE BAND CENTER FREQUENCY (Hz)
                                                              80
FIG.  7.   SOUND  PRESSURE LEVELS FROM AIR CONDITIONER ON
         SETTINGS  (MEASURED AT 3 ft)
                                          TWO
                               40

-------
 of  the  compressor, motor, and  fans, a total noise reduction of
 10  to 15  dS(A)  is not unreasonable.  Perhaps an appropriate de-
 sign goal for high cool operation is 40 dB(A). at 3 ft.

     Dishwashers
     A  dishwasher is essentially a tub equipped with a water spray
 system  that is  driven by a motor-pump assembly.  Heating coils
 and a blower are provided to assist in the drying operation.  A
 complete  wash may consist of as many as thirteen cycles:  rinse,
 fill, wash, drain, fill, rinse, drain, fill, rinse drain, fill,
 rinse,  drain.   Figure 8 plots  the noise level in dB(A) as a func-
 tion of operation [
-------
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                        DRAIN
                                  RINSE
                               •RINSE-
                                                             DRAIN
      RINSE
              123   4)5 6  7  8 9 10
                                          ii       i  i   i  i
                          5           10           15
                                TIME IN  MIN
                                                             20
F r e q .  in Hz
    31.5
    63
   125
   250
   500
  1000
  2000
  4000
  8000
Overall
A-welghted
O
58
                                                        ©

                62
                59
                61
                61
                60
                55
                69
                66
55
57
61
60
62
59
55
52
49
68
64
65
62
64
69
66
66
62
59
55
74
70
64
60
60
67
64
66
61
58
54
73
69
64
61
60
70
66
68
63
62
58
75
72
53
53
54
58
60
59
57
52
46
67

51
51
58
58
59
57
54
52

66
62
55
54
60
59
63
59
56
52
49
67
64
64
62
62
68
66
66
62
59
55
74
70
65
61
61
69
66
69
63
62
58
75
72
FIG.  8 .   GRAPHIC LEVEL RECORDING AND OCTAVE BAND  SOUND  PRESSURE
         LEVELS OF A DISHWASHER.
                                42

-------
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    31.5
 FIG. 9
      1945


      1955
1 MACHINE

(FROM REF. 10)
      RANGE OF NOISE  MEASUREMENTS

      ON FIVE MACHINES  (1971 )
 63     125    250    500    1000   2000   4000

     OCTAVE BAND CENTER FREQUENCY IN Hz
                                                            8000
SOUND PRESSURE LEVELS OF VARIOUS  AUTOMATIC DISHWASHERS

DURING WASH  CYCLE (MEASURED AT 3  ft)


-------
     Through the use of experimental splash curtains,  which pre-
vent impingement of the water spray on the tub walls,  water noise
has been reduced by 6 to 8 dB(A) [ll].  The motor-pump assembly
is often isolated from the tub by rubber mounts;  however,  the
effectiveness of these mounts can be reduced in the installation
process by an insufficient clearance between the  motor and the
floor.
     Often, the sides and top of a dishwasher are brought  into
contact with the cabinet.  A clearance of 1/2 in. all  around the
machines, with neoprene isolation pads insuring the clearance,
will reduce the noise radiated by the cabinet as  well  as the
noise transmitted to other parts of the house.  The use of rubber
hoses for supply and drainage are an improvement  over  the  copper
tubing often provided.  The incorporation of acoustic  material
in the motor-pump enclosure and a kick panel that is sealed (no
air leaks) would also reduce the noise.  It is anticipated that —
if
   • water noise were reduced (e.g., by installing splash  cur-
     tains) ;
   • effective vibration isolation of the motor-pump from  the
     tub were ensured;
   • effective vibration isolation of the dishwasher housing from
     the floor, cabinet walls and top were ensured;
   • rubber hoses were used;
   • acoustical absorption material were installed in  the  motor
     enclosure; and
   • the kick panel were sealed air-tight -
the noise levels of a typical dishwasher could be reduced  by some
10 to 15 dB(A), from a level in the mid sixties to one in  the low

-------
fifties.  Because of its intermittent operation,  a p;oal of 45 to
fjO dB(A) at 3 ft is probably acceptable.

     Food Waste Disposers
     Continuous-feed and batch-feed disposers are chambers in
which food waste is ground by a motor-driven wheel with cutting
edges. Figure 10 presents one-third octave band sound pressure
level data.for four different disposers.   Although the details
of the spectra differ, each has a .major peak at 125 Hz and sev-
eral minor peaks at higher frequencies, all superimposed on broad--
band noise.  The peak at 125 Hz is primarily motor noise.  The
minor peaks can be attributed to the blade-passage frequency of
the grind wheel, multiples thereof, and resonances in the sink.
The broadband noise is generated by the sloshing of water and
waste against the housing of the chamber.
     Noise is transmitted up through the mouth of the disposer.
Batch-feed disposers, which require the sink cover to be in place
before operation, have the potential for being quieter.  Continu-
ous-feed units sometimes have partial rubber closures at the
mouth of the unit (primarily to prevent food waste from being
expelled); for these closures to be effective in controlling
noise, they must overlap to shut off the entire opening.
     Basic noise control treatments that have been moderately
successful include vibration isolation of the disposer from the
sink and the enclosure of the chamber and motor with a double wall
construction.  It;is estimated that the noise levels generated
by disposers could be reduced by .about 10 dB(A) with the follow-
ing treatments:
   • effective vibration isolation of the disposer from the sink;
   • damping of the sink;

-------
10
 31.5
63     125     250    500     1000    2000   4000   8000

ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
   10. SOUND PRESSURE LEVELS rROM FOUR FOOD-WASTE  DISPOSE,::
      (MEASURED AT 3-ft)


-------
    • flexible connections between the disposer and the drain
     pipe, which will also reduce the noise transmitted to other
     rooms and/or apartments;
    • flexible electrical connection;
    • enclosure of both the grinding chamber and motor, with
     appropriate ventilation; and
    • effective-closure of the mouth of the disposer.

     Vacuum Cleaners
     Cafti^ter. vacuum cleaners consist of a tank (either horizon-
tal or.'for two upright vacuum cleaners -.,.a
large unit' ;wi'fefr a beating; mechanism"'a^                    a
beater.   For the larger unit, the low frequency noise is again

-------
  80
10
 31.5
           63     125     250    500     iQOO    2000   4000
            ONE-TH RD OCTAVE BAND CENTER FREQUENCY IN Hz
8000
FIG.  11.   SOUND  PRESSURE LEVELS OF CANISTER VACUUM CLEANERS
          OPEPATING ?N VOOP PR TjLr- FLOORS ('MEASURED AT  3  ^

-------
                         	WITHOUT BEATER
           63     125     250    500    1000   2000   4000
           ONE-THIRD OCTAVE BAWD CENTER FREQUENCY IN Hz
8000
FIG.  12.  SOUND PRESSURE  LEVELS OF TWO UPRIGHT  VACUUM CLEANERS
         (MEASURED AT 3  FT)

-------
motor-induced.  The peaks In the higher frequency range are
caused by Pan(s) and/or structural radiation.  The difference be-
tween the two units in the low-frequency bands is due to the dif-
ference in capacity as well as to the lack of a beater on one
model.  Noise control for upright cleaners will be more difficult
to achieve than for the canister units because of the location of
the beater and the limitations on size.  It is anticipated that a
5 dB(A) noise reduction could be achieved on the typical unit.

     Water Closets
     Water closets are either of the tank type or the valve type
and are either floor-mounted or wall-mounted.  Figure 13 illus-
trates the time history of the sound pressure level in the 250
Hz octave band for operation of a tank water closet [22].  Time
Period A represents the valve opening and releasing water in the
tank to flow into the bowl through an opening in the base of the
bowl.  The water produces a swirling action in the lower half of
the bowl (Time Period B).  The valve closes (Time Period C) and
the tank and bowl are refilled (Time Period D).
     Figure  14 illustrates the time history of the sound pressure
level in the 250 Hz octave band for a flush valve water closet [22]
The valve opens (A);  air and then water are forced out of the rim
supply (B);  the valve closes (C)  and the bowl is refilled (D).
A comparison of these two figures suggests that flush valve water
closets generate somewhat higher initial noise levels during an
operating cycle but that the noise does not persist as long as
with tank water closets.  Since the character of the sounds is
different,  it is not  clear at this time which would be more de-
sirable.
                               50

-------

   TIME PERIOD

   A= VALVE OPENING
   B = TANK EMPTYING
   C=TANK CLOSET VALVE CLOSING
   D=TANK AND BOWL FILL
     30
TIME IN SEC
                                                         40
50
                                                                                    60
FIG.  13-   TIME  HISTORY OF THE SOUND PRESSURE LEVEL IN  THE  250  HZ  OCTAVE BAND FOR A
          TANK  WATER CLOSET.

-------
                    90
                UJ
                >
                UJ
    TIME PERIOD

A= VALVE OPENING
B= WATER FLOW
C= VALVE CLOSING
D= BOWL FILL
                               5         10
                               TIME IN SEC
                    15
FIG.  14.  TIME HISTORY  OF  SOUND PRESSURE LEVEL  IN  250 HZ OCTAVE
         BAND FOR A FLUSH  VALVE WATER CLOSET
                             52

-------
     Figure 15 presents peak octave band data for a sampling of
tank water closets and Fig. 16 for flush valve water closets.   A
comparison of these two figures shows that it is possible to have
relatively noisy or quiet operation with either type of water
closet provided.  For tank water closets, water flow control and
inlet water pressure are both important variables in the noise
generated [22]. For flush valve closets, bowl design was found
to be of major importance, with valve type (exposed flush vs re-
cessed flush) and mounting (floor vs wall) of lesser importance.
Resilient mounting of water closets and piping was found to be
more important for some fixtures than for others - e.g., a range
of several dB(A) to 15 dB(A) for valve-operated water closets.

2.3  Building Equipment
     The proper operation of large buildings requires a number of
different types of electrical and mechanical equipment.  In this
section, we review the noise levels generated by electrical and
mechanical equipment, present noise levels for a typical multi-
story building, and discuss the possibilities of noise control
through architectural modification.  Detailed descriptions of
additional building equipment types are given .in Appendix A.

2.3.1  Types of equipment
     The majority of electrical and, mechanical equipment in build-
ings is used to supply the building occupants 'with a suitable
quantity of air at a comfortable temperature and moisture content,
In addition, pumping and piping systems are used for water and
fluid circulation, elevators and escalators are used for movement
of personnel, and various/conveyance systems are used for moving
material.
                               53

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     31.5
   125    250     500     1000    2000
OCTAVE BAND CENTER FREQUENCY IN  Hz
4000   8000
FIG.  15.   RANGE  OF  PEAK OCTAVE BAND SOUND PRESSURE  LEVELS  IN

          ROOMS  WITH TANK TYPE WATER CLOSETS (MEASURED  AT  3  FT)

-------
  20
    31.5     63     125     250    500    1000   2000   4000
               OCTAVE  BAND CENTER FREQUENCY IN Hz
8000
FIG.  16.   RANGE OF PEAK OCTAVE BAND  SOUND  PRESSURE LEVELS IN
          ROOMS WITH FLUSH VALVE WATER  CLOSETS  (MEASURED AT 3  FT)


-------
     ?igure 17 presents the typical range of sound levels In d3(A)
at 3 ft for building equipment.  Much of this equipment is hidden
in mechanical equipment rooms, above ceilings, in walls, or behind
cabinet type exterior enclosures.  Table VII, which summarizes
the exposure of occupants to the noise generated by building equip-
ment, shows that occunants are diveotly exnosed to the noise of onlj
about ei~ht different types of equipment.  The noise generated by
these units is thus of special interest since there are no inter-
vening walls to provide attenuation.  The noise generated by
bulletin,--; equipment hidden from view can be sufficiently attenu-
ated through the proper use of current architectural techniques.
In practice, such techniques are not always implemented.

2.3.2  Noise levels within a typical multistory building
     Although details of the frequency spectrum are of consider-
able importance in selecting noise control treatments, the model
presented in this section is keyed, for simplification, to
dB(A);  it is not intended that this method be used for actual
situations.  Figure 18 presents a cross-section of a multistory
building, locating a typical occupant with respect to building
equipment.   Figure 19 summarizes the noise exposure in dB(A) of
an occupant to individual sources.  The higher level in each case
is representative of the sound level near the source — e.g., at
3 ft.  The  lower level is representative of the level to which
the contribution from a particular source is reduced through pro-
per implementation of noise control techniques.  The treatments
include:
     E — enclosure of noise source
     D — ductwork lined with acoustically absorbing material
     W - wall

-------
       Ballast
       Fluorescent  Lamp
       Fan Coil Units
       Diffusers,  Grilles,
       Register
       Induction Units
       Dehumidifiers
       Humidifiers
       Mixing Boxes,
       Terminal Reheat
       Units, etc.
       Unit Heaters
       Transformers
       Elevators
       Absorption
       Machines
       Boilers
       Rooftop
       Airconditioning
       Units
       Pumps
       Steam  Valves
       Self-contained
       Airconditioning
       Units
       Chiller  - Rotary
       Screw  Compressors
       Condensers - Air-Cooled
       Pneumatic
       Transport Systems
        Central  Station
       Airconditioning Unit
        Chiller  - Reciprocating
        Compressor
        Electric Motors
        Fans
        Chiller  - Centrifugal
        Compressor
        Air Compressor
        Cooling  Towers
        Diesel Engines
        Gas Turbines
FIG.  17.
                 2O  30  40  50  60 70  80  90 100  110 120 130
                        A-weighted  sound  level

RANGE  OF SOUND  LEVELS  IN  dB(A) TYPICAL  FOR  BUILDING
EQUIPMENT  AT  3  FT.
                                         57

-------
         TABLE  VII.   EXPOSURE  OF  BUILDING  OCCUPANTS  TO  THE
                   NOISE OF BUILDING EQUIPMENT
Building
Equi pment
Air
Conditioning


Absorption
Machines
Air Compressor
Ballasts
Boilers
Boiler Feed
System
Chillers
Condensers
Cooling
Towers
Dehumldlfiers
Diesel Eng.
Diffusers
Electric
Motors
Elevators
Escalators
Pans

Furnaces
Gas Turbines
Heat Pumps
Humidifiers
Mixing Boxes
and Air
Control Units
Pneumatic
Transporter
System
Pumps
Steam Valves
Transformers
Unit Vent and
Unit Heat
Location
MER*
Roof. Unit
Wind. Unit
MER
MER
Room
MER
MER
MER
Rooftop
Rooftop
MER
MER
Room
MER
Varies
Varies
MER
Room
MER
MER
MER
MER
Varies
Varies
MER
MER
MER
Room
Type of Exposure
Direct


X


X







X

X
X

X




X




X
Indi rect
Through Mechanical
Distribution System
X
X









X



X
X
X




X
X
X




Through Walls,
Floors, etc.
X
X

X
X

X
X
X
X
X
X
X

X
X
X
X

X
X
X
X

X
X
X
X

*Mechanical Equipment Room
                                58

-------
    FLOOR
    SLAB
 BALLAST
                             COOLING
                               TOWER
                                 PENTHOUSE  MER
                         *'  - •" - A
     y//yys
              DIFFUSER-
ELEVATOR
 ROOM
  FOR
 FLOOR
 BELOW
                            MIXING
                            BOX
           FAN
                      • \
              • -x-.-
                          DIESEL  ENGINE
              ^^•-
                  AIR
              COMPRESSOR
  PUMP  BOILER   TRANSFORMER
FIG. 18.  .CROSS-SECTION  OF A TYPICAL  MULTISTORY  BUILDING SHOW-

           ING BUILDING  EQUIPMENT.

                                 53

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                            A- WEIGHTED SOUND LEVEL
30   40   50   60
                                    70   80   90   100  110  120
LAMP BALLASTS
AND  VAPOR


DIFFUSERS


MIXING  BOXES


FAN COIL


TRANSFORMERS


PUMPS


BOILERS


STEAM  VALVES


CHILLERS


ELEVATORS


AIR COMPRESSORS


COOLING TOWERS


FANS

DIESEL  EMERGENCY
GENERATOR

o«-

f


o*-


V.


<
(
(
(


<




•

We








— E+D —


j* i

N-»
S^



*—







s^








1





-•




W- INTERVENING WALL
D - DUCT TREATMENT
E - ENCLOSURE OF EQUIP.
R - INTERVENING ROOF
STRUCTURE
S - BUFFER ZONE FLOOR
BETWEEN SOURCE AND
OCCUPANT'S FLOOR
V - VIBRATION ISOLATION
OF EQUIPMENT
\A/4-*'
W













W.



h V

/ + V




^+V






M
+ R +
h D+'













V/ ii. , i.



/
V
\A/4-
















\f

































• SOUND LEVEL AT 3 FT FROM SOURCE
O SOUND LEVEL AT OCCUPANT'S POSITION

FIG.  19.  RANGE OF  BUILDING EQUIPMENT NOISE  LEVELS TO  WHICH

         PEOPLE ARE EXPOSED.
                            60

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     R — roof slab
     S — intervening story — e.g., the penthouse mechanical
         equipment floor
     V — vibration isolation.
     Goals for acceptable noise levels vary with the activities
to be held in a-space.  If one is interested in increasing the
spee.ch. privacy within-.an office, then a higher noise level of an
appropriate spectral shape would be appropriate.  On the other
h;and, if one is performing certain types of tests or listening to
cjritical sounds,,- a quieter environment is required.  Through the
use of current technology, it is possible to achieve virtually
                                         /
any noise goal,;if the owner of the building is willing to bear
the cost and space requirements of the treatment.  Of course, by
specifying quiet equipment, the owner may minimize these require-
ments.
                                61

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3.   IMPACT
3.1  Noise Level Criteria for Impact Evaluation
     In this report, the impact of noise exposure upon people is
evaluated primarily in terms of three direct effects and secon-
darily in terms of a number of indirect consequences.   The three
major effects are hearing-damage risk, speech interference, and
sleep interference.  The rationale for emphasizing these effects
is twofold.  First, they are among the most salient and tangible
consequences of noise exposure and thus can be most readily inter-
preted in nontechnical terms.  Evidence that they are widely
understood by the public may be found in their frequent mention
in noise complaints.  Secondly, research on these three effects
has been more extensive than on other noise effects; therefore,
clearer predictions can be made with greater confidence.
     Although the three primary effects are used to summarize the
major impact of noise exposure, the indirect consequences of ex-
posure also demand consideration.  These effects include physio-
logical stress, annoyance, startle, and task interference.  They
are termed "indirect" in that they are not produced exclusively
by noise, nor are they simple functions of the physical magnitude
of noise exposure.  Further, relatively little systematic infor-
mation about these effects is available; thus, specification of
precise levels of noise exposure leading to particular  levels of
effect is a somewhat speculative matter.  However, one may not
assume that these secondary consequences are unimportant merely
because they are difficult to quantify.
     The following table presents the physical levels at which it
is felt that each of the above-mentioned effects of noise expos-
ure achieves (1) a moderate level of effect and  (2) an  appreci-
able level of effect.  The decisions leading to  these specifica-
tions are discussed below.
                                62

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      TABLE VIII.  ESTIMATES OF MAGNITUDES OF NOISE EFFECTS
                            [IN dB(A)]

       Effect              Moderate Level       Appreciable  Level
Hearing Damage Risk              70                     90
Speech Interference              ^5                     60
Sleep Interference               40                     70
Physiological Stress              *                     90
Startle                           *                    110
Annoyance                        40                     60
Task Interference                55                     75

3.1.1.  Hearing-damage risk
     The hearing-damage risk levels specified in Table VIII were
selected on the basis of eight hours of daily exposure.  Exposure
durations of this order are chosen as representative of the amount
of time usually spent in home and work environments.  Since hear-
ing-damage risk is cumulative over long periods of time [13], the
recommendations are intended to account for prolonged noise ex-
posure over a period of years.
     The estimate of the level at which hearing-damage risk com-
mences was determined on a rather stringent basis.  The Walsh-
Healey Public Contracts Act, as amended to include noise  limits
for hearing conservation, is based on a CHABA report [24], which
permits permanent threshold shifts up to  10 dB at  frequencies
^Effects at low levels are at best weak functions of the physical
 intensity of noise.  They are determined*far more strongly by
 factors such, as the meaning associated with the acoustic signal,
 attitudes toward the -source, rise time: of the signal, unexpect-
 edness of the signal, and so forth.  It  therefore makes little;
 sense to specify discrete levels in;these cases.
                                63

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below 1000 Hz; up to 15 dB at 2000 Hz, and up to 20 dB at fre-
quencies above 3000 Hz.  Hearing losses of these magnitudes are
considered inconsequential in the sense that they are ineligible
for compensation under the terms of the legislation.  Even these
surprisingly lax limits are based on th<-.- questionable assumption
of a sixteen-hour daily recovery period of little or no noise
exposure [J3].  Further, the CHABA report [14~] is intended to
afford this partial protection to only half of the population ex-
posed to noise.  Clearly, these criteria are neither applicable
to individual circumstances nor capable of protecting many people
from sizeable hearing losses.
     Kryter's published redefinition of the hearing-damage risk
criteria [J5] maintains that no permanent threshold shift whatever
is tolerable at frequencies below 2000 Kz and that no more than a
10 dB shift is tolerable at higher frequencies.   Kryter also ap-
plies the protection afforded by his definition to 75/2 of the
nopulation rather than 50*.  He states that the ''threshold" of
hearing-damage risk for eight hours of daily exposure is 67 dB(A).
Cohen et al [35]operating under similar assumptions specify
75 dB(A) as the level at which hearing-damage risk commences.
Miller [l£] believes that a level of 70 dB(A) represents a level
of noise exposure above which hearing-damage risk becomes nonnegli'
gible.   In Miller's terminology, habitual exposure to levels be-
tween 70 and 30 dB(A) represents yellow (i.e., cautionary) risk
of hearing damage;  exposure to levels between 80 and 90 dB(A) en-
tails "orange" risk; while exposure to levels in excess of 90 dB(A
involves "red" (serious) risk.
     The estimate of Table VIII for the onset of hearing-damage
risk agrees with Miller's estimate.  The estimate of the level
at which appreciable risk of hearing damage occurs agrees both

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with Miller's estimate and the provisions of the Walsh-Healey  Act.
The latter criteria, based on a report of the NAS-NRC Committee
on Hearing, Bioacoustics, and Biomechanics [24], indicates  that
eight hours of daily exposure to levels in excess of 90 dB(A)
constitutes a serious risk of hearing damage to one-half of the
population.

3.1.2  Speech interference
     The levels specified in Table VIII for speech interference
are the most straightforward and readily defensible of all  of  the
estimates.  A criterion for adequate verbal communication in the
home was taken to be comprehension of 98% of all sentences  or  an
equivalent rate of comprehension of 85$ of the words of a stand-
ard phonetically balanced (PB) list.  In terms of nominal vocal
effort [approximately 65 dB(A) at a distance of one meter], such
a level of speech intelligibility would be sustained at a speaker-
listener distance of approximately five meters in a noise back-
ground of 45 dB(A) [37].  Five meters was taken to be the maximal
distance at which conversation in normal levels might reasonably be
expected to be held in a quiet outdoor (nonreverberant) environ-
ment.*  The level of appreciable effect specified in Table VIII
was derived by assuming that noise-induced speech interference
would be intolerable if conversation at nominal levels of vocal
effort were precluded at speaker-listener distances greater than
one meter.  Such conditions prevail in noise environments in ex-
cess of 60 dB(A)
*Greater speaker-listener distances would be possible indoors at
 the same levels of vocal effort and speech intelligibility, be-
 cause sound pressure levels diminish more slowly than predicted
 by the inverse square law.
                                 65

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     It should be pointed out that selection of the above criter-
ion represents a belief that the 70% comprehension of PB words
suggested by Webster [17~\ and Beranek [7S] does not provide for a
reasonable standard of communication in the home.  V/ebster's cri-
terion was established for "barely adequate communication" and is
inappropriately applied to the home environment.  The levels re-
commended in this report are thus 6 dB lower than Webster's.

3.1.3  Sleep interference
     Two principal ways in which noise exposure can interfere with
sleep are to delay the onset of sleep  and to shift sleep "stages"
Scores of studies are available on the sleep-delaying and stage-
shift effects of noise exposure.   Although there is frequently
broad agreement among studies, detailed agreement is lacking.
Discrepancies among outcomes of similar studies are attributable
to incomparable control conditions, differences in experimental
design, and the host of individual differences which beset sleen
research.
     For example, it is universally observed that the initial
time required for subjects to fall asleep increases monotonically
with exposure to increasing noise levels.  Unfortunately, differ-
ent studies produce estimates of the sleep-delaying effects of
noise that are more than 35 dB apart.  Thus, two studies report
delays in onset of sleep from 20  to 90 minutes \_19,20~\, corre-
sponding to exposure to continuous noise at levels of 35 dB(A)
and 50 dB(A), respectively.   Other studies, [21—25] however, re-
port that subjects can fall asleep in as little as twelve minutes
despite exposure to noise levels  of 70 dB(A).
     Further, prolonged exposure  to high noise levels can produce
tinnitus (ringing in the ears), which has been claimed to delay
                                66

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 the onset of sleep  [24].  In other words, aftereffects of noise,
 even  in the absence of any noise exposure at bedtime, can impede
 sleep.  It is also  claimed in the literature that levels as low
 as 35 dB(A) can either induce a shift from a "deeper" to a
 "lighter" level of  sleep or awaken certain people [25],  Pronounced
 differences In sensitivity to noise during sleep have been observed
 as a  function of age as well.
      An absolute criterion for noise exposure levels in sleeping
 quarters is obviously unjustifiable on the basis of extant re-
 search.  A conservative criterion for noise exposure (from the
 point of view of minimizing sleep interference) might be based
 on the lowest levels at which sleep interference have been re-
 ported.  According  to the Wilson Report 126J, levels of 40 dB(A)
 have  been known to  awaken approximately 25% of the sleeping
 population, while levels of ^5 dB(A) appear to keep about 20% of
 the population from falling asleep immediately.  These considera-
 tions have led to the adoption of 40 dB(A) as a criterion level
 for the onset of sleep interference effects.  According to the
 Wilson Report data, a little more than half of the population m?.y
 be awakened.by noise exposure to levels of 70 dB(A), while a little
 less  than half of the population will find some difficulty in
 falling asleep when exposed to such levels.  These data led to
Adoption of 70 dB(A) as the level at which sleep interference
 effects become considerable.

 3.1.4  Physiological stress
      The amount of  stress"produced by low-level acoustic signals
 3.s primarily determined by their meaning.' A footfall in one's
bedroom at night, or a growling animal, ;or one's boss's voice can
Excite stress mechanisms by virtue of their implications rather
                                 67

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than their physical attributes.  Since it is the learned and in-
stinctive associations to sounds which are largely responsible
for their ability to create stress,  no level of minimal effect
has been specified.
     At high noise levels a somewhat stronger case may be made
for specification of a criterion.  Studies of physiological cor-
relates of noise-related stress in animals surest that, noise
levels in the vicinity of 90 dB(A) produce strong effects [27].
Pupillary dilation, increased pulse pressure and heart rate, and
pulse volume changes have been observed in humans exposed to
noise levels of approximately 70 dB(A) [25].  There can be little
argument that at even higher levels  noise stimulation induces
stress in and of itself, rather than as an exclusive function of
its meaning.  Extremely intense noise fields can cause auditory
and bodily pain.  Such intense fields commonly are associated with
strong vibrational components, which can also be harmful.

3.1.5  Startle
     The arguments above about the relative roles of meaning and
levels of acoustic signals in determining stress also apply to
startle.  For the same reasons, therefore, no minimal level of
effect can be specified.
     A major obstacle to establishing a firm criterion for tiie
startling effects of high level noise is the phenomenon of habi-
tuation.  In general, humans display a marked decrease in sensi-
tivity to repeated exposure to startling sounds.  Expectedness}
regularity, familiarity, arousal level, and numerous other fac-
tors strongly mediate startle effects.  Even at high absolute
noise levels, startle is as much affected by signal-to-noise ratio
considerations as it is by the level of the startling signal.
                                68

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Thus, an exploding paper bag would almost certainly produce more
startle in a library than in a boiler factory.
     The level recommended in Table VIII is therefore chosen to
represent a noise level sufficiently rarely heard and of a signal--
to-noise ratio sufficiently great to make a significant startle
reaction highly probable.

3.1.6  Annoyance
     The levels recommended in Table VIII.for gauging annoyance
effects are intended to reflect the lowest level at which any of
the other tabled effects can occur.  In other words, one is ex-
pected to be annoyed by a noise sufficiently intense to produce
sleep interruption, speech interference, etc.
     It is, of course, also true that long-term exposure to very
low level noises can be annoying.  A dripping faucet or a chalk
squeak can be exceptionally irritating.  Once again, however, it
is the meaning of the acoustic signal rather than its level per se
which plays a major role in determining the magnitude of annoy-
ance.  Also, the spectral composition and temporal density of
noise heavily influences its annoyance value.  Unfortunately,
temporal and spectral factors cannot be adequately expressed in
dB(A).

3.1.7  Task interference
     The literature on the effects of noise on human performance
contains numerous conflicting and inconclusive reports.  By and
large, high-intensity, aperiodic, intermittent noise is reported
to impede efficient work to a greater extent than low-intensity,
steady-state noise [25].  Nonetheless, numerous studies find no
effects of noise on performance, while a  few studies find
                                69

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paradoxical improvements In performance attributable to noise
exposure [SO].  Of course, improvements in performance when an
environment is changed (presumably worsened)  are often due to
changes in the level of attention perceived by the subject and
their attendant reaction.   The nature of the task at hand and
the duration of noise exposure also influence the extent of task
i n' ?rference .
     it is our feeling that the :nost sensitive and complex tasks
(of the nature of brain surgery, diamond cutting, etc.) might be
sensitive to interference  from noise at levels as low as 55 dB(A).
Although most  published studies which report task interference
give levels in the vicinity of 90 to 110 dB(A),  it is felt that
certain tasks  might prove  susceptible to appreciable interference
at approximately 75 dB(A).

3.2  Construction Noise
3.2.1  Extent  of exposure
     Our determination of  the impact of construction noise on the
American public is based on information obtained about the number
of people exposed to such  noise and the extent of their exposure.
This information was gathered in four steps:
   • We determined the number of construction sites of various
     types in  various geographical regions.
   • We determined the density of people in the geographical re-
     gions (two classes of people were considered: stationary
     population such as workers and residents and transient popu-
     lation such as drivers and pedestrians) •
   • We postulated a model of sound propagation around a typical
     construction site.
                               70

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   • We combined the Information obtained in the first  three
     steps with the site source level 'data presented in Sec.  2.1
     to determine the number of people exposed to given levels
     of noise.
     For the purpose of gathering and analyzing population and
construction site statistics, we divided the U.S. into  five re-
gions.  These regions are based on those defined by the U.S.
Bureaus of the Budget [51~\ and of the Census [32].   A key to
understanding the rationale used for establishing these regions
is the concept of Standard Metropolitan Statistical Area (SMSA).
An SMSA is a group of continguous counties which contains at
least one central city of 50,000 inhabitants or more, or "twin
cities" with a combined population of 50,000 or more.  There  are
233 SMSAs containing 65% of the nation's population and about 10%
of the land area.  The population density in the nonmetropolitan
areas is too low to create much construction noise exposure or
to allow meaningful computation of the exposure that does exist.
This study, therefore, restricts itself to construction occurring
within the SMSAs (see Table IX).

     Classification of Construction Sites
     As explained in Sec. 2.1, four major categories of construc-
tion were studied:
   • Residential buildings
   • Nonresidential buildings
   • Municipal roads
   • Public works
     Certain heavy construction and large civil works,  such as
dams and bridges, were omitted because this type of construction
                               71

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           TABLE IX. METROPOLITAN  REGIONS  CONSIDERED  IN
              CONSTRUCTION NOISE EXPOSURE  ESTIMATE;
                      STATISTICS AS  OF  1970*
                     Population     Area
                     (thousands )  (s q .  mi.)
Large High-Density
Central Cities** (12)  22,250

Large Low-Density
Central Cities   (14)  10,530

All Other SMSA
Central Cities  (186)  25,820
Urban Fringe

Met. Area. Outside
Urban Fringe
      49,680


      22,320
  1,468


  2,389


  6,981

 14,707


179,276
                            Population Density
                           (people per sq.  mi . )
15,160


 4,410


 3,710

 3,380


   125
 *Population figures are extrapolated to 1970 from 1969 Census
  figures according to recent growth rates.
**Large cities are those whose metropolitan area population ex-
  ceeded 1,000,000 in I960.
  High-Density
  Low-Density:
Baltimore, Boston, Buffalo, Chicago, Cleveland,
Detroit, New York, Philadelphia, Pittsburgh,
San Francisco, St. Louis, Washington.
Atlanta, Cincinnati, Dallas, Denver, Houston,
Kansas City, Los Angeles, Milwaukee, Minneapolis-
St. Paul, Miami-Ft.  Lauderdale, New Orleans,
St. Petersburg-Tampa, San Diego, Seattle-Tacoma.
                               72

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3?arely takes place in heavily populated areas.  The residential
and nonresidential building categories were further subdivided
Into specific types of buildings to account for variations in the
duration of construction and the mix of machinery at different
kinds of sites.

     The Number of Construction Sites
     Data on the annual number of building sites on which con-
struction was begun in 1970 was collected from the U.S. Business
and Defense Services Administration [33] and from unpublished
compilations made by the Bureau of the Census.  Data for large
central cities and for the nation as a whole were directly avail-
able; sites were ascribed to "other central cities", "urb'm
fringe", and "nonurbanized metropolitan area" on the basis of
population distribution.  The number of residential and nonresi--
Qential building sites in the five metropolitan-area regions is
shown in the first two columns of Table X, as well as the aver-
age cost of construction for each case.  A more detailed break-
down by type of building is given in Appendix B.
     Data on total municipal road construction [34] was appor-
tioned among the various metropolitan regions by assuming a con-
stant ratio of miles of road constructed to miles of road in
fclace.  The number of miles of such work performed in 1969 is
shown in the third column of Table X.
     Unlike the case with buildings and roads, data on construc-
tion and maintenance of public works such as sewers and water
*nains is not collected on a national basis.  The extent of this
construction, therefore, has been estimated first by determining
the ratio of sewer construction to street construction for sev-
eral cities in the Boston area and then by usinp this ratio to
                               73

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               TABLE X.  ANNUAL CONSTRUCTION ACTIVITY - 1970*
                        Residential   Nonresidential  Municipal
                         Buildings       Buildings     Streets   Public Works
Metropolitan Regions  (no. of sites)  (no. of sites)   (miles)       (miles)
Large high-density
central cities

Large low-density
central cities

Other central cities

Urban fringe

Met. area outside
urban fringe


Total
  8,708


 21,578

102,559

262,800


118,779

514,424
 1,952
13,758


62,549
   273
 4,903       2,150

12,021       6,000

30,915      11,800
21,700


41,923
   398


 3,140

 8,700

16,865


31,550


60,653
  All figures are in thousands.

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estimate the miles of sewer construction nationwide for 1970.
These figures are contained in the fourth column of Table X.   A
more detailed description of this computation is contained in
Appendix B.

     Construction Phases
     Construction of buildings and other works is carried out  in
discrete stages,  each of which has its own characteristic mix  of
equipment.  Because of the items of equipment on a site change
as construction progresses, the noise output from the site also
changes with time.  As explained in Sec. 2.1, we have character-
ized the noise output from each site according to construction
phase:
   • Clearing and demolition
   • Excavation
   • Placement of foundations
   • Erection of frame, floors, roof, and skin
   • Finishing and cleanup.
These phase descriptions are used for road and sewer construction,
even though the actual operations are different  from those for
buildings, so as to allow a consistent analysis  of the various
types of sites.  (See Sec. 2.1 for a more complete description.)
A list of the equipment commonly found in each phase is  given in
Table A-l.

     Number of Individuals Exposed
     We obtained the number of people exposed to various  levels
of noise from construction sites by combining information on
                                75

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population density, the number of sites active per year, and the
sound propagation model described below.
     We revised the population figures in Table IX, which repre-
sent the residential distribution of the U.S. population, to re-
flect the net transfer [35] of people from suburbs to central
city during the average working day, the period when most con-
struction noise is produced.  These revised density figures are
given in Table XI in terms of people per square mile and people
per one-eighth mile of street (assuming the entire metropolitan
area to be divided into city blocks one-eighth of a mile long).
              TABLE XI.  GEOGRAPHICAL DISTRIBUTION OF
                      WORKING-DAY  POPULATIONS
                                                   People per
                            People per         1/8 mile of street
                            square mile           (approximate)
Large high-density
central cities                16,650                   120
Large low-density
central cities                 4,860                    40
All other central
cities                         4,070                    32
Urban fringe                   3,100                    24
Met. area outside
urban fringe                     114
Note that the number of people per city block in the metropolitan
area outside the urban fringe is negligible and therefore is dis-
regarded in the following discussions.
                               76

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     In addition to the working-day population density estimate
given in Table XI, we must also account for the number of passers-
by who are exposed to construction noise.  Since there are no data
on typical driver and pedestrian distributions, a definitive esti-
mate of this type of exposure is not possible.  We have, however,
made an order»of-magnitude estimate on the basis of some survey
work performed by the Boston Traffic Department (1970).  Although
incomplete, these surveys report seemingly reasonable numbers,
which are-therefore offered in Table XII as preliminary estimates.


               TABLE XII.   NUMBER OF PEOPLE PER DAY
                   PASSING A CONSTRUCTION SITE
Large high-density central cities
Large low-density central cities
Other central cities
Urban fringe
Drivers and
 Passengers
    3000
    3000
    1500
     500
Pedestrians
    1000
    1000
     500
     100
     Table XIII presents the total number of building construction
sites active in 1970 (see Table X) for all metropolitan regions.
In the case of roads and sewers, the definition of a "construc-
tion site" is somewhat obscure, since such projects extend linearly
for some distance with construction usually occurring one section
at a time.  The, area of influence of construction on pne section
is about one-eighth of a mile.  :Wetherefore consider each
eighth-mile of street and sewer construction as an independent
site.                                      .
                               77

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        TABLE  XIII.   LEVEL  OF  ANNUAL  CONSTRUCTION ACTIVITY
                                        Number  of  Sites
                Type  of  Site            (National  Total )
          Residential Building
          Nonresidential                     62,5^9
          Municipal Streets                 336,000
          Public Works   .                   485,000
     The level of exposure to noise from a construction site  de-
pends on one's distance from the site and the nature  of his  im-
mediate environment.   In city streets, it has been found experi-
mentally that sound intensity decreases as the inverse square of
the distance from the source [35].   In logarithmic units, this
amounts to a 6 dB reduction per distance doubled.   This model has
been adopted for open-air propagation, which is significant  in
the case of pedestrians.  In addition, a factor of 20 dB(A)  at-  .
tenuation has been included for people tfho are inside buildings
with closed windows and 15 dB(A) for people inside cars with
closed windows [27].   Construction noise is assumed to propagate
along the street adjacent to the site, but to be heavily attenu-
ated in the direction transverse to the street; in effect, only
the people along the street adjacent to the site are  affected by
the noise.  A further assumption is that the sound is reduced
10 dB(A) when one crosses a street intersection
     Using these parameters, we illustrate in Pig. 20 a repre-
sentative geometry for a building construction site and contours
of attenuation for observers.  Details of the computations in-
volved in constructing this diagram are given in Appendix B.
Assuming a uniform distribution of observers along the sides  of
                                78

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CENTER OF SITE
R0 •50'
BUILDINGS^
STREET
           y////////////.
                     32dB  35dB
                     x       /
                                       660-
                                                          38dB
   .FIG. 20,  CONSTRUCTION SITE  GEOMETRY AND ATTENUATION CONTOURS FOR

            A STATIONARY POPULATION WITHIN BUILDINGS.  fSEE APPEN-

            DIX B FOR METHOD OF COMPUTATION.)
                                79

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the street, we can determine the fraction of people within each
set of attenuation contours.  These proportions, which are shown
in Table XIV below, apply only to observers in buildings with
closed windows adjacent to the street on which building construc-
tion is taking place; drivers and pedestrians move relative to
the site, crossing contours as they go.
         TABLE XIV.   DISTRIBUTION OF STATIONARY  OBSERVERS
                 RELATIVE TO ATTENUATION CONTOURS
Attenuation Interval
     26 - 29 dB
     29 - 32 dB
     32 - 35 dB
     35 - 40 dB
                                      Percent of Observers
                                               15$
                                               32%
                                               18%
     All observers more than 40 dB away from the site have been
disregarded, as they are assumed to be unaffected by the noise.
The actual number of people within each pair of attenuation con-
tours can be obtained by multiplying the percentages in Table XIV
by the number of people per 1/8 mile of city street for the appro-
priate metropolitan area (as given in Table XI).
     In the case of street and sewer construction, operation is
typically distributed along the length of the street and cannot
be modeled as a point source.  Accordingly, all the people in
the eighth-mile of city street adjoining the site are assumed to
be exposed to the same noise level.  This level is taken to be
the source level of the site diminished 20 dB to account for at-
tenuation within buildings with closed windows.
                                80

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     The noise exposure of pedestrians and drivers cannot be  com-
puted by the above model, since, as noted above,  their distance
from the site varies with time.  In these cases,  we consider  the
peak exposure experienced by the transient observer.   For pedes-
trians, this exposure is 6 dB less than the site  source level
referenced to 50 ft; for drivers, it is 20 dB less.

     Noise Exposure Estimates
     The above figures on observer densities, number  of sites,
and attenuation have been combined with the data  on average and
peak site source levels presented in Sec. 2.1 to  determine the
number of people exposed to particular levels of  noise.  Table  XV
shows the national noise exposure of the stationary population
due to residential building, nonresidential building, municipal
street, and public works construction.  The noise levels are
broken down into the five phases of construction  described above.
     To compute exposure of drivers and pedestrians,  one multi-
plies the number of people per day passing each site by the
number of sites.  This gives the number of passersby exposed per
day of site operation.  Multiplying this number by the average number
of days each site is operated gives the total annual number of
instances in which an individual passes a construction site and
is thus exposed to noise.  For this computation,  we use the num-
ber of sites from Table X and the number of passersby from Table
XII.  The duration of construction on the average site is not
available from survey data but the following, figures are consid-
ered typical:
   • Residential buildings (single-family only) — 27 days
   • Nonresidential buildings and multifamily dwellings — 170 days
   • Streets and Public Works — 7 days.
                                81

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                TABLE  XV.   AVERAGE  AND  PEAK  EXPOSURE  LEVELS  TO  CONSTRUCTION  NOISE
CO
r\j
         lumber  of  People
                      Average Levels
                    Construction Phase
                                         Peak  Levels
                                     Construction Phase


1,725
4,025
3,680
2,070
11,500


,000
,000 .
,000
,000
,000
I

56.5
53-5
50.5
47-5

II

54.5
51.5
48.5
45.5

III
RES
54.5
51.5
48.5
45.5

IV
IDENTI
47.5
44.5
41.5
38.5

V
AL BUI
54.5
51.5
48.5
45.5

I
LDING COr
63.5
60.5
57.5
54.5

II
^STRUCT
70.5 '
67.5
64.5
61.5

III
ION
57-5
54.5
51.5
48.5

IV

57.5
54.5
51.5
48.5

V

70.5
67.5
64.5
61.5

  225,000
  525,000
  480,000
  270,000
1,500,000
            14,500,000*
             7,000,000*
56.0  57-5
53-0  54.5
50.0  51.5
47.0  48.5
NONRESIDENTIAL BUILDING CONSTRUCTION
50.5  51.0  56.5    63-5  70.5  60.5
47.5  48.0  53.5    60.5  67.5  57.5
44.5  45.0  50.5    57-5  64.5  54.5
41.5  42.0  47-5    54.5  61.5  51.5
60.5  70.5
57.5  67.5
54.5  64.5
51.5  61.5
                      MUNICIPAL STREET AND PUBLIC WORKS CONSTRUCTION
               63.0  65.0  68.0  58.0  64.0    71.0  78.0  71.0  69.0  71.0

                          FEDERAL AND STATE HIGHWAY CONSTRUCTION
               63.0  65.0  68.0  58.0  64.0    71.0  78.0  71.0  69.0  71.0
         ^Assuming  homogeneous  exposure  of  all  people  indoors  with'windows  shut.

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The estimated number of occasions per year in which .a driver or
pedestrian passes a site is shown in Table XVI below.  These
figures do not represent the number of people who pass construc-
tion sites, since one person may pass many sites, or one site
many times.  If one divides the grand total of Table XVI, 24.7
billion passings, by the total national metropolitan population
of 137 million;, it is seen that the average Inhabitant of metro-
politan areas passes a construction site approximately 180 times
per year.

3.2.2.  Impact assessment
     Determining the impact of construction noise on people is a
multistage process.  The procedures by which estimates of levels
and durations of noise exposures were derived are discussed in
the preceding section (3.2.1).  Development of the criteria by
which the severity of noise effects are judged is discussed in
Sec. 3.1.  In this section, we explicitly combine the exposure
data with the criteria; Appendix B contains a number of important
comments on the inferences which may be prudently drawn from the
findings reported here.
     Table XV of Sec. 3.2.1 and Table XVII of this section provide
an overview of the exposure data as they pertain to impact assess-
ment.  The tables contain information about the number of people
who receive primary and secondary exposure to construction site
noise and the levels of noise to which they are exposed -in their
listening environments.   Estimates of the duration of noise ex-
posures are also presented in the tables.  The following discus-
sion is organized according to strength of impact.
                                83

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         TABLE XVI.  ESTIMATED ANNUAL PASSINGS OF CONSTRUCTION SITES -
              ALL METROPOLITAN REGIONS* (MILLIONS OF OCCURRENCES)


                Residential     Nonresidential     Municipal Streets
                 Bui 1 dings         Bui 1 dings        and Public Works      Total'

Drivers and
  Passengers

Pedestrians
                                                       Grand Total       24,782
8,300
2,760
8,160
2,700
1,980
882
6,3^2
*A "passing" is defined as one person passing one site by car or foot.

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    Speech Interference
    Perhaps the single most obvious effect of  exposure  to  con-
struction site noise is speech interference.  Even  cursory  exam-
ination of Table XV reveals that  in almost all  phases  of construc-
tion, noise levels associated with construction activity are
capable of degrading speech communication.  In  many instances  —
specifically, those in which construction noise produces levels
approaching or exceeding  60 dB(A) in the listening  environment -
degradation of speech communication is  severe.   When one considers
that the "average" levels of Table XVII are energy  averages,  it
is  clear that peak levels of construction noise, although infre-
quent, can preclude speech  communication completely.
    It is apparent from  Table XVII that for  those  people who
live or work in the vicinity of  construction  sites  (i.e., those
who receive  primary exposure to  construction noise),  the dura-
tion of speech interference effects can be  considerable.  It  seems
safe to state that approximately  3^ million people  suffer a total
of  several hundred hours  of speech interference yearly as a re-
sult of exposure to construction  site  noise  in  the  United States.
Approximately 20 million  of these people must communicate in
noise environments which  seriously degrade  speech intelligibility
and/or demand significantly increased  vocal  effort.
    In contrast to those who must endure  such  speech interfer-
ence on a  relatively  long term basis,  there  are many more people
who suffer the same effects on a briefer  time scale.  These
people are the passersby  who  are  exposed  to  construction site
noise for  a matter  of  minutes  daily.   Although  the  actual number
of different  individuals  who  pass by  construction sites on foot
or in vehicles is  difficult to estimate,  there  are  probably on
the order  of  25  billion such  brief  encounters yearly.  The prin-

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                TABLE XVII.  ORDER OF MAGNITUDE ESTIMATES OF YEARLY DURATION OF
                                  CONSTRUCTION NOISE EXPOSURE
oo
            Source


Primary (Stationary) Exposure
to Domestic Construction Noise

Primary (Stationary) Exposure
to All Other Building Con-
struction

Primary (Stationary) Exposure
to All Other Construction in
SMSA Areas

Municipal Public Works

Federal and State Highway

        Subtotal

Secondary (Passerby) Exposure
of Pedestrians to Construc-
tion in All SMSA Areas
                                        Number of People
                                            11,500,000
                                             1,500,000
     Hours  of  Exposure  by
      Construction  Phase
I
24
II
24
III
40
IV
80
V
40
  80   320   320   480   160
14

7
,500

,000
,000

,000
8
12
250
8
12
250
16
24
500
16
24
500
8
12
250
                                         6,342,000,000*
        Secondary (Passerby) Exposure
        of Drivers and Passengers to
        All Construction in SMSA Areas  18,440,000,000*

                Subtotal
Five minutes'  exposure to
levels approximately 30 dB
higher than those of Table XV

Thirty seconds'  exposure to
levels approximately 15 dB
hie-her than those of Table XV
        *These figures represent the number of annual occurrences of exposure, defined
         as the produ-et of the number of people exposed and the frequency of their

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cipal effect of such  transient  exposure  to  construction noise is
probably interruption of  conversation.
    Applying state-of-the-art  noise  reduction technique's to the
major sources of  construction noise  could provide a meaningful
reduction of both the severity  of speech interference and the
number of people  exposed  to  speech interference effects.   Quiet-
ing all construction  equipment  by 10  dB(A)  would lower peak con-
struction noise levels  by  an equivalent  amount and average levels
by a somewhat lesser  amount  (due  to  overlapping temporal patterns
of use).  Nonetheless,  speech interference  effects increase
sharply in  the range  between 40 and  60  dB(A),  so that a noise re-
duction of  about  10 dB(A)  could be highly beneficial.  Interest-
ingly enough, the. advantages of reducing construction noise an
additional  10 dB(A) might  not be  as  great.   Although 20 dB(A)
reduction of construction  noise would clearly  result in even less
speech interference than  would  a 10  dB(A) reduction, at the re-
sulting levels construction  noise might  well be submerged in
background  noise  a good part of the  time.   Additional reductions
[beyond the first 10  dB(A)]  might be  necessary for the benefit of
those who operate the equipment,  however.

    Sleep  Interference
    To the extent that construction  activity  and sleep do not
commonly occur during the  same  hours, construction noise does not
interfere with sleep.  However, daytime  sleeping needs of the
very young, the sick, and  people  working irregular or night hours,
and emergency and other nighttime construction work must be taken
into-account.  The total  number of adults so affected by construc-
tion is estimated to  be about 3 million. Judging from the ratio
of people exposed to  construction noise  to  the total population of
the country, approximately 15$  of the children four years of
                                87

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 age  or younger,  or about  2.5 million, might also be exposed to
 sleep interference from construction noise.
     The 5.5 million people attempting to sleep during exposure
 to construction  noise  are  likely  to encounter substantial inter-
 ference.  Even at relatively great distances from construction
 sites, levels in the vicinity of  50 dB(A) are encountered.  Such
 levels are capable of  significantly lengthening the time required
 to fall asleep and of  awakening roughly 40$ of sleeping persons.
     Nonetheless, the  usefulness  of reducing average construction
 noise levels by  10 dB(A)  (possible through state-of-the-art noise
 reduction procedures)  appears marginal.  The number of people
 whose sleep is disturbed by construction noise is relatively
 small, and the shallow slope of the function relating the number
 of people awakened to  noise levels argues that construction noise
 would have to be reduced by much  more than 10 dB(A) to effect a
 significant reduction  of sleep interference.

     Hearing-Damage Risk
     The risk of hearing damage from construction noise for those
 not directly concerned with construction activity does not seem
 very great.  In most cases the distance between the construction
 site and people  exposed to its noise and the transmission loss of
 the buildings or vehicles  are sufficiently great to minimize the
probability of hearing damage..  It is possible that peak noise
 levels from construction sites might present some risk to those
who are frequently in  close proximity to the site.  The greater
number of such people  (presumably pedestrians), however, are sub-
 ject only to short exposure durations.
     If state-of-the-art noise reduction techniques were applied
to the major sources of construction noise, exposure levels would
                                88

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probably be sufficiently reduced to render hearing damage a remote
risk.  In short, construction noise does not pose a major hearing-
damage risk for the public.

     Other Indirect Effects
     Without doubt, a major consequence of exposure to construc-
tion noise for many people is annoyance.  Both those who are ex-
posed to construction noise  on a regular, long-term basis as well
as those who are exposed to it on a transient basis are annoyed
by their exposure.   Annoyance is particularly great if the noise
intrusion from the construction site is perceived as unnecessary
or inappropriate.  People who must endure weeks or months of
construction noise exposure may exhibit some form of habituation
to the noise, but despite the commonly expressed attitude toward
noise of "you get used to it", it is doubtful that construction
noise ever loses all of its annoyance value.
     In relative terms, annoyance from construction noise prob-
ably represents less of a problem than annoyance produced by air-
craft or traffic noise.  Nonetheless, both individual complaint
behavior and community action could conceivably result from the
annoyance of exposure to construction noise.
     One measure formulated to provide some degree of quantifica-
tion for annoyance due to noise exposure is the Noise Pollution
Level [2].  Table I contains NPL's encountered in the immediate
vicinity of construction sites.  Unfortunately, interpretation
of NPL's is not a straightforward procedure.  Relative interpre-
tations of- two or more noise situations  are readily enough made
through use of the NPL index.  Few grounds exist, however, for
absolute interpretations.  It has been suggested that long-term
exposure to noise levels characterized by an NPL value of 72
                                 89

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 (computed from A-level measurements) is "acceptable" £2].  By this
 criterion, noise levels in the immediate vicinity of construction
 sites are clearly "unacceptable" on a long-term basis.  However,
 the bulk of exposure to construction noise of such high levels
 is of a transitory nature.  Residents or transients exposed to
 construction noise would be exposed to levels about 30 dB lower.
 Although it would be tempting to assert that such exposure (to
 NPL's in the range of 60—70) would be marginally acceptable, only
 meager evidence could be marshalled to support such a claim.
     It is distinctly possible for exposure to construction noise
 to result in task interference.  It seems plausible that among
 the approximately 20 million people exposed on a long-term basis
 to the highest levels of construction noise (Table XV), some might
 be engaged in exacting manual or mental work which could be sensi-
 tive to interference.  Such tasks might include medical operations
 library use, scholarly activities, and the like.  Unfortunately,
 one cannot quantify the amount of task interference produced by
 construction noise by applying the usual procedures of estimation
 and assumption.
     Similar comments apply to the potential startle and physio-
 logical stress produced by exposure to construction noise.  Al-
 though startle does not seem to be a very common consequence of
 exposure to construction noise, it is nevertheless possible for
 startle to result from unexpectedly or intermittently high-level
noise.  The size of the standard deviations of distributions of
 construction noise levels discussed in Sec. 3.2.1 makes the
 occurrence of unusually high noise levels reasonably probable
events.
     As for the stressful consequences of exposure to construction
noise, we can offer only informed conjecture.  Noise-induced
                               90

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physiological stress is known to be cumulative,  and exposure  to
construction noise is only one determinant.   Perhaps some  of  the
people who are faced with exposure to construction noise  at work
every day for months must also face noisy home environments.   For
such people, exposure to construction noise  could constitute  a
major source of stress.
     Tables XVIII and XIX summarize the impact of construction
noise on people.   A composite quantity intended to reflect both
the extent and duration of exposure to specific noise sources was
developed to permit concise summation.  The  quantity IS defined
as the product of the estimated number of people exposed to noise
from a particular source and the estimated duration of individual
exposure to the same source.  The statistic  expressing the quan-
tity is called (for lack of a better term) the "person-hour".
     Extreme caution must be used in interpreting figures ex-
pressed in terms  of person-hours.  First, figures so expressed
are intended only as order-of-magnitude estimates rather than as
precise quantities.  Second, inferences about the equivalence of
number of people  and duration of exposure in assessing psycholog-
ical or physiological impact are completely  unjustified.  No com-
pensatory model of number of people exposed and exposure duration
is intended.  Third, comparison of person-hour figures for expo-
sure to noise from one source with person-hour figures for expo-
sure to noise of another source is without theoretical foundation,
Thus, comparisons of impact among different  sources expressed in
common terms of person-hours should be performed in a fashion
similar to "addition" of apples and oranges.  In other words,
inferences about  severity of impact may be drawn only withint
person-hour estimates of similar origin.
                                91.

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        TABLE XVIII.  ORDER-OF-MAGNITUDE ESTIMATES OF CONSTRUCTION

           NOISE EXPOSURE IN MILLIONS OF PERSON-HOURS PER WEEK


             Source                      Millions pf Person-Hours Per Meek

Primary (Stationary) Exposure to
Domestic Construction Noise                             46

Primary (Stationary) Exposure to
All Other Building Construction                         39

Primary (Stationary) Exposure to
All Other Construction in SMSA Areas                    16

                            Subtotal                   101

Secondary (Passerby) Exposure to
Pedestrians to All Construction in
SMSA Areas                                              10

Secondary (Passerby) Exposure of
Drivers and Passengers to All
Construction in SMSA Areas

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OJ
          Noise Source
          TABLE XIX.   ORDER-OF-MAGNITUDE ESTIMATES OF IMPACT  OF  PRIMARY  AND

                SECONDARY  EXPOSURE  TO CONSTRUCTION  NOISE  EXPRESSED  IN

                          MILLIONS  OF PERSON-HOURS  PER WEEK

                    Speech  Interference*   Sleep Interference*

                                           Slight

                                           (35-50)
Moderate
                           (45-60)
Severe
 (>60)
Moderate
 (50-70)
Primary (Station-
ary) Exposure to
Domestic Construc-
tion Noise

Primary (Station-
ary) Exposure to
All Other Build-
ing Construction

Primary (Station-
ary) Exposure to
All Other Construc-
tion in SMSA Areas

Secondary (Pass-
erby) Exposure of
Pedestrians to
Construction in
All SMSA Areas

Secondary (Pass-
erby) Exposure of
Drivers and Pas-
sengers to all
Construction in
SMSA Areas
                             38
                                        10
                                         0.3
                         0
                          0
                                                                       Hearing Damage Risk
Slight
(70-80)
Moderate
 (80-90)
                                                                                    10
                                                                                     0-3
      *Entries in these columns may not be interpreted directly as person-hours of direct
       speech or sleep interference (see text).

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     With these restrictions firmly in mind, the reader is refer-
red to Tables XVIII and XIX for a concise summary of the impact
of construction noise on people.  Table XVIII expresses the im-
pact of construction noise in terms of millions of person-hours
per week. (It may be useful to bear in mind that a week in the
United States contains approximately 35 billion person-hours.)
Table XIX relates the impact of construction noise directly to
the principal criteria of Sec. 3.1 in terms of person-hours per
week.  Entries for speech interference and sleep interference
effects reflect the number of person-hours of potential impact,
which may be interpreted as upper bounds.

3.3  Appl i ances
3.3.1  Extent of exposure
     This section is concerned primarily with power tools and
household appliances whose volume cannot be controlled by the
user.  Therefore, volume-controllable equipment such as televi-
sions, radios, and stereos are not included, nor are gasoline-
engine powered outdoor equipment and audible signaling mechanisms
(bells, alarms, etc.).  It should be noted, however, that non-
controllable noise-producing devices often raise the background
level of noise to such a degree that volume-controllable sound
has to be increased in level to be heard and, hence, is more apt
to affect neighbors.  An estimate of the number of noncontrollable
noise-producing devices being used in the United States in 1971
is given in Table XX.
     To determine the  extent of exposure to home appliance and
tool noise,  we gathered three kinds of data:  The distribution
of appliances and tools over family units, the time that the de-
vices are typically in use, and the exposure of people who are

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  TABLE XX.  NONCONTROLLABLE  HOUSEHOLD  NOISE  SOURCES (1971)
                                                 Percent of Homes
Wired Households

Complete Plumbing

Major Appliances

  Refrigerator
  Clo'thes Washer
  Vacuum Cleaner
  Clothes Dryer
  Freezer
  Air Conditioner
  Dishwasher
  Food  Disposer
  Trash Disposer

Other Appliances

  Food  Mixer
  Can Opener
  Sewing Machine
  Food  Blender
 'Electric  Shaver
  Slicing Knife
  Floor Polisher

Power Tools

  Saw,  Drill,  etc.

Outdoor Equipment

  Electric  Mower
  Edger
  Trimmer

Building Equipment
(residential)

  Fan
  Humidifier
  Dehumidifier
lumber  (thousands)

     62,80C                   100

     58,000                    93
      62,600
      57,600
      56,900
      25,300
      20,000
      18,000
      14,900
      14,400
           (introduced  in  1970)
99.8
91.9
90.7
40.3
30.0
29.6
23.7
22.9
      51,200                    81.7
      27,100                    43.2
      31,300                    50.0
      19,900                    31.7
      25,000                    ^0.0
      25,000                    40.0
      10,000                    16.0
      12,500                   20.0
       2,000*                   3.2
       1,000                    1.6
       4,000                    6.4
      50,000                   80.0
       4,600                    7.4
       4,200              -      6.7
*There are approximately 37 million powered mowers in use.
                                95

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 in  the  home.   In  collecting  this  information, we  found that the
 variables,  particularly with regard to personal behavior, covered
 a very  large range.  We therefore created a simplified model to
 show  the  extent of household noise.
      Data were obtained from a variety of jources.  Statistical
 information was collected from government sources, such as the
 Bureau  of the Census.  Of particular help was information pro-
 vided by Cornell  University's College of Human Ecology on domes-
 tic living patterns.  Industry information was obtained from
 various trade and business publications.  Individual company ma-
 terial  was used in instances where the material was applicable
 to the  whole industry and was available to the public.  Various
 organizations representing consumers and home economists were
 contacted.  We also conducted our own survey of appliance use in
 20 households.

     Appliances,  Tools,  and Building Equipment
     The dimensions used by industry to analyze household appli-
ance purchase and use patterns usually include home ownership,
age of  the head of the family,  size of family, and family income.
Since these dimensions are interrelated, we chose only one —
family  income level — for our analysis.   We treat the time that
appliances are used as a function of the age of the homemaker
and of  the number of school and pre-school children in the fam-
ily.  Figure 21 shows the trend toward greater use of home appli-
ances and power tools.   Figure 22 gives the distribution of some
common appliances as a function of income level.
     Noise-producing devices used in and around the home are
usually classified as
                               96

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vo
—J
        100
        90
      CO
      o
        80
        70
      o

      I 60
      O
      X
      UJ
      o
      cr
        50
        40
        30
        20
         10
              1960
 1  REFRIGERATOR

   CLOTHES WASHER

   VACUUM CLEANER


   FOOD MIXER
             AIR CONDITIONER
   CAN OPENER

   CLOTHES DRYER


   FOOD BLENDER

   DISH WASHER
   FOOD DISPOSER

   POWER TOOLS
1970
       FIG. 21.   PERCENT OF HOUSEHOLDS WITH SELECTED NOISE-PRODUCING APPLIANCES

                AND TOOLS.

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co
     100
     90
   o
   I
   UJ
   CO
   ^
   o
   IE
     80
70
     60
   2 50
   (O

   Q 30
   f-
   z

   o 20
   o:
   UJ
   CL-
      IO
                           I
                                                                  REFRIGERATOR
                                                                  CLOTHES WASHER
                                                             CLOTHES DRYER
                                                             DISH WASHER
                                                                  AIR CONDITIONER
           6    8    10   12   14    16    18   20   22   24

          FAMILY  INCOME BEFORE TAXES ($ THOUSANDS)
                                                                26
   FIG. 22-   ESTIMATED PERCENT-DISTRIBUTION OF MAJOR  APPLIANCES BY INCOME LEVEL

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   •  Major Appliances (including c-lothes  washers,  clothes dryers,
     refrigerators and freezers, air conditioners, dishwashers,
     vacuum cleaners, disposers, dehumidifiers,  and comoactors)
   •  Other Household Appliances
   .  Power Tools
   .  Outdoor Equipment
   .  Building Equipment
Other convenient classifications are based on time mode of  oper-
ation (continuous or intermittent) and method of operation  (man-
ual or automatic).
     Analysis of the noise-producing building equipment used in
homes is complicated by interaction of the equipment with the
structure of the house, by do-it-yourself modifications of equip-
ment, and by differences in the adequacy of equipment maintenance.
Size of housing is also a factor in noise level.  Smaller housing
units are apt to be noisier because of reverberant buildup of
sound levels.  Larger housing units on the other hand, frequently
reflecting a higher standard of living, tend to have more appli-
ances and more frequent exposure but lower noise  levels for any
particular appliance owing to the larger space and to the room
separation from the various sources.  Multiple-family housing
units are subject to higher levels  of noise from  the building
equipment.
     In heating systems either  the  heating source  or distribution
system or both are  common sources of noise; however, the number
of factors involved  is too great  to allow a precise analysis of
the extent of heating noise.  Electric heating, which  is essen-
tially noiseless, is  currently  being used by 4.4  million customers,
                                99

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 (It should be noted, however, that electric heating customers are
 likely to be high users of electric appliances.  Furthermore,
 humidity control, ventilating, and/or air cleaning, which are
 often used in conjunction with electric heating, require air cir-
 culation; therefore, fan noise is present where these additional
 functions are performed.)  The more common heating systems gen-
 erate burner noise, fan/duct noise (in hot-air systems), and
 pipe, valve, and pump noise (in hot water and steam systems).
     Twenty-one percent of all households have one or more room
 air conditioners.  Location of these air conditioners is distrib-
 uted approximately [35]:
          Living Room       35%         Kitchen      1%
          Master Bedroom    21%         Playroom     ^%
          Other Bedroom      5$         Other       22%
     All dehumidifiers and many humidifiers are substantial noise
 sources.   Frequently, dehumidifiers are located in the basement
 and therefore direct exposure to the noise is small.  Dehumidi-
 fiers are used in 6.7% of homes; humidifiers in 7 -^% {.S8~\-
     Living patterns, equipment installations, etc. are variables
 that make it difficult to estimate the extent of plumbing noise.
The typical range of toilet flushes is 10 to 50 per day.  Com-
plete plumbing (hot and cold water, bath or shower, toilet) is
 found in 82% of all rental units and in 93% of all owner-occupied
units in the United States.
     The number of fans being used in this country far exceeds
the total number of households.  Many fans are part of other
appliances,  but many are used for immediate air circulation
 (i.e.,  cooling fans, kitchen fans, etc.).
                               100

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     Use of Domestic Appliances  and Tools
     The extent to which appliances are used is  an  important  fac-
tor in assessing the total noise exposure.   Statistical  informa-
tion is scarce, but we have found the following  sources  useful:
   • BBN survey (in-depth study  of noise levels  and appliance
     use in 20 homes).
   • New York State College of Human Ecology, Cornell  University
     (both published and unpublished data gathered  as  part  of a
     1296-household survey of Syracuse, New York).
   • Department of Agriculture information based on studies of
     home activities (a long-term interest, which is now being \
     continued under the Agriculture Research Service  Division
     of the Department of Agriculture).
   « Potomac Electric Power Company (an informal survey conducted
     by their Home  Services Department).
   • Manufacturer's industry information.
     Although many factors affect the range of appliance use,
there is a tendency for people in the family-raising years to
have increased incomes, own their homes, and possess more appli-
ances.  The time a homemaker spends in household activities  is a
strong  function of age, number of children, and the presence of
pre-school children, as shown in Table XXI.  Table XXII presents
the information on which we base our estimate of typical use of
aDpliances; Table XXIII gives our estimate  of appliance use  in
two typical households; appliance operating times  are estimated
from Table XXII.  Using the values  of appliance use (total min-
utes per week) and of average noise  levels  given in Table  XXIII,
we present in  Fig. 23 a schematic illustration of  the noise  levels
Of the  two typical households.
                               101

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   TABLE XXI.   AVERAGE HOURS PER DAY  SPENT  ON  HOUSEHOLD  WORK  BY
   1296 HOMEMAKERS, ACCORDING TO NUMBER OF  CHILDREN AND  AGE OF
      YOUNGEST CHILD, SYRACUSE, NEW YORK AREA, 1967-68 [39]

                                                  Hours
          All homemakers 	   7-3
          Number of children
            0 	   4.8
            1 	   6.8
            2 	   7.8
            3 	   7.7
            4 .. .	   8.2
            5 or 6 	   8.5
            7 to 9 	   9.2
          Age of youngest child
            Under 1 year 	   9.3
            1 year 	   8.3
            2 to 5 years 	   7.7
            6 to 11 years 	   7-1
            12 to 17 years 	   6.0
     Level of Exposure
     We have selected two criteria to show different measures of
exposure.  A potential exposure represents the number of people
likely to be exposed to an appliance and depends solely on an
average distribution of the population and the percentage of
households that possess the particular appliance.   A primary ex-
posure is estimated by the normal mode of operation, the location
                               102

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      TABLE XXII.  APPLIANCE USAGE SOURCE DATA (TIMES PER DAY UNLESS INDICATED)
        Appliance
 Clothes  washert
 Clothes  dryer
 Dishwasher
 Pood disposer
 Vacuum cleaner
 Room air conditioner
 Trash disposer
 Pood mixer   )
 Pood blender f
 Can opener
 Sewing machine
 Slicing  knife
 Floor polisher
 Electric shaver
 Power tools (saw, etc.)
Mower

 No. of  Loads
  on One Day
                              Cornell  University  Data,  1296 Homes*
* • ———.*.— u v • « «_ »-j »__ w i 1 1 u in u 1 1 i—\**jt\j\jyj
m i.
0>  > 0
0 C ^_
•C.™ a _ Number of days in one week
•*-•— w ^ua which appliance was used.
O Q. 3 -Q CF>
Q. CVJ
•i-*  .C CU o
o +-> u .,_


ler






etc. )

Loads
Homes
Q.

30
24
97
17
98



48


72
0
502
: (U
D_
62
22
48
28



3



1
210
0
135
931
1002
111
277



1161



2
263
1
104
4
1
211
226



107



3
159
2
167
5
5
275
286



17



4
82
3
197
13
2
260
207



6



5
44
4
163
33
5
164
153



1



6
18
5
163
25
3
76
80



0



7
6
6
178
14
10
80
28



0



8
4
7
189
272
268
119
39



4



Ave.
1.50
O +-> Q,
O Q.+J
o> ,0 _c^-
U Q E 4J C
•r- .,_ -.- 
U (J  (U •—
••- E T-
•— >r_ o ^:
LJJ s_ ^ ^: o
0 CO j_ S_ 00

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         TABLE XXIII.
USE OF NONCONTROLLABLE NO ISE-PRODUCING  APPLIANCES  AND

      TOOLS IN TYPICAL HOUSEHOLDS
                                 Household  No.  1*
                                         Household  No.  2
                                                                               t
Major Appliances

  Clothes washer
  Vacuum cleaner
  Clothes dryer
  Room air conditioner
  Dishwasher
  Food disposer

Household Appliances

  Pood mixer
  Can opener
  Sewing machine
  Food blender
  Electric shaver
  Slicing knife
  Floor polisher
  Trash disposer

Power Tools

  Saw, drill, etc.
  Mower
  Edger
  Trimmer
                        Average
                         dB(A)1
    64
    70
    57
    58
    65
    70
           Times
         Used Per
           Week2
        Minutes
       Per Use3
  Total
 Minutes
Per Week
10.5     30        315
 3       30         90
 7       30        210
(full-time — seasonal)
10.5     ^5        472
 6        0.2        1
69
69
72
76
64
71


2
14
1
3
7
1
1
14
                     5
                     0.2
                    15
                     1
                     2
                     1
                    10
                     1
83

81
81
0.5
l
0.75
0.25
20
30
5
15
                    10
                     2
                    15
                     3
                    14
                     1
                    10
                    14
                               10
                               30
                                4
                                4
  Times
Used Per
  Week
            7
            2
Mi nutes
Per Use
            30
            25
  Total
 Mi nutes
Per Week
           210
            50
            3

            0.5
             5

            15
            15

            15
 *2 Adults,  3  children  (1  pre-school  age),  family  income  $16,000.
 t2 Adults,  family  income  $8,000.
 Measurements taken  3  ft  from  source during  BBN household survey.
 2Based  on data from  BBN survey,  Cornell  Univ.  survey  of  Syracuse, N.Y., and Potomac
  Electric Power Company information.
 3Based  on average  cycle times  of cur-rent model appliances.

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90

80


70

dBA 60
50
40
*n
I I I I I 1 I 1 1 1
i
HOUSEHOLD NO. 1
—
BLENDER
SEWING MACHINE
1 	 .VACUUM CLEANER
1 MIXER DISHWASHER , CLOTHES WASHER
CLOTHES
-
1 1 I 1 I I I I i I
—


-

DRYER "
-
REFR9.
1
dBA
80
70
60
50
40
•v\
I 1 I 1 I 1 1 1 I 1 l
HOUSEHOLD NO. 2
BLENDER
VACUUM CLEANER
^-VMIXER
DISH WASHER
-
1 I
-
-
REFRIGERATOR
1 I 1 I 1 I l l i
                 APPLIANCE IN  USE,  MINUTES PER WEEK
   FIG.  23.  NOISE PROFILES FROM APPLIANCE  FOR TYPICAL HOUSEHOLDS
            PER WEEK (AT 3 ft)
            No. -1: AVERAGE-INCOME FAMILY WITH CHILDREN
            No. 2: LOWER-THAN-AVERAGE-INCOME  FAMILY WITHOUT CHILDREN
                                 105

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 of  the appliance, and the number of operators and observers likely
 to  be exposed to noise when the appliance is operating.  Table
 XXIV gives these two kinds of exposure for each appliance; Table
 XXV relates exposure to income level.

 3.3.2  Impact assessment
     The estimates of the extensiveness of distribution, duration
 of  exposure, and noise levels of a variety of building equipment
 and home appliances are discussed here with a view toward assess-
 ing the impact of noise from these sources on people in the home
 environment.  To approximate the environment in which noises are
 heard, we had to adjust the noise levels from the standardized
 values used in previous sections (i.e., levels recorded at a
 measurement position 3 ft from the source).  Thus, 10 dB was
 added to the noise levels of hand-held appliances, such as elec-
 tric shavers, to obtain a fair representation of noise levels at
 the user's ear.  Similarly, 2 dB was subtracted from levels for
 exposure to noise in a highly reverberant field, such as a kitchen
 or bathroom; 3 dB from standardized measurements to account
 for noise exposure in less reverberant spaces, such as carpeted
 (living room) or open areas; 10 dB from the standard values to
 compensate for exposure in adjacent rooms connected by open doors;
 and 20 dB to represent the transmission loss of a typical frame
 house to noise from external sources (such as powered yard tools).
 Levels for about thirty typical home appliance and building noise
 sources adjusted in this manner appear in Table XXVI.
     Table XXVII classifies the noise sources discussed in the
 previous section of this report into four categories:  (1) Quiet
Major Equipment and Appliances, characterized by operating levels
 lower than 60 dB(A); (2) Quiet Equipment and Small Appliances,
                               106

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  TABLE XXIV.  NUMBER OF INDIVIDUALS EXPOSED TO

   INDICATED APPLIANCES (MILLIONS - 1970)  [33]
                          Potential       Primary
                           Exposure      Exposure

Major Appliances

  Refrigerator               199            70
  Clothes washer             183            65
  Vacuum cleaner             l8l            66
  Clothes dryer               80            28
  Freezer                     63            23
  Air conditioner             60            21
  Dishwasher                  47            17
  Food disposer               46            17
  Trash disposer

Household Appliances

  Pood mixer                 163            59
  Can opener                  86            31
  Sewing machine             100            36
  Food blender                63            23
  Electric shaver             80            25
  Slicing knife               80            80
  Floor polisher              32            40

Power Tools

  Saw, drill, etc.            40            13

Outdoor Equipment

  Electric Mower                6              2
  Edger                         3              1
  Trimmer                     12              4

Building Equipment
(residential)

  Fan                        160            90
  Humidifier                  15              5
  Dehumidifier                13              1
                        107

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o
co
    Family Income
    ($ thousands)

    Under 5
     5 - 10
    10 - 15
15 and over


Total
                   TABLE XXV.   ESTIMATED NUMBER OF INDIVIDUALS  EXPOSED  TO

                         DOMESTIC  APPLIANCE  NOISE  (MILLIONS - 1965)*
   Typical
  Appliance
  Possession

Mostly only
essential

Wide variety
of appliances

Often most
appliances
                                                     Potential  Primary  Exposure

Total
House-
holds
12.6
21.2
16.8
12.0
62.8

Potenti al
Secondary
Exposure
41
71
55
39
200


"Home-
makers "
12.6
21.2
16.8
12.0
62.8

Children
Under
6 yrs .
2.9
6.0
5.0
3.8
17.7


Night
Workers
0.6
1.0
0.8
0.6
3.0
Total
Persons
Primary
Exposed
9.9
18.8
14.4
10.5
83.5
    *Calculated from average distributions and income information in Ref. 36.

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    TABLE XXVI.   SOUND PRESSURE  LEVELS  OF  HOME  APPLIANCES AND

 BUILDING EQUIPMENT  ADJUSTED  FOR  LOCATION  OF  EXPOSURE [IN dB(A)]
         Noise Source

Group I: Quiet Major Equipment
         and Appliances

Refrigerator
Freezer
Electric Heater
Humidifier
Floor Fan
Dehumidifier
Window Fan
Clothes Dryer
Air Conditioner

Group II: Quiet Equipment and
          Small Appliances

Hair Clipper
Clothes Washer
Stove Hood Exhaust Fan
Electric Toothbrush
Water Closet
Dishwasher
Electric Can Opener
pood Mixer
Hair Dryer
Faucet
Vacuum Cleaner
Electric Knife

Group III: Noisy Small
           Appliances
Electric Knife Sharpener
Sewing Machine
Oral Lavage
pood Blender
Electric Shaver
Electric Lawn Mower
pood Disposal  (Grinder)

Group IV: Noisy Electric  Tools
Electric Edger and Trimmer
Hedge Clippers
Home Shop Tools
Level  of
Operator
Exposure
   40
   Hi
   44
   50
   51
   52
   54
   55
   55
   60
   60
   61
   62
   62
   64
   64
   65
   66
   66
   67
   68
   70
   70
   72
   73
   75
   75
   76
    81
    84
    85
Level  of Exposure  to
   People  in Other
        Rooms
         32
         33
         37
         43
         44
         45
         47
         48
         48
         40
         52
         53
         42
         54
         56
         56
         57
         51
         51
         60
         60
         62
         62
         62
         65
         52
         55
         68
          61
          64
          75
                               109

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         TABLE XXVII.   ORDER-QF--MAGNITUDE  ESTIMATES OF THE EXTENT AND DURATION OF

                    EXPOSURE TO  BUILDING EQUIPMENT AND HOME APPLIANCES

        NOISE SOURCE         PRIMARY EXPOSURE*  DURATION1"  SECONDARY EXPOSURE*   DURATION1"
Group  I: Quiet Major
Equipment and Appliances
Refrigerator                        70            25              200              10
Fans                                90            10              178               5
Air Conditioner                     21             3               80               1
Humidifier                           5             3               15               5
Clothes Dryer                       28             0.5             80               ~>
Freezer                             23             0.25            20               0.50
Group  II: Quiet Equipment
and Small Appliances

Plumbing (Faucets, Toilets)        200             2              200               5
Vacuum Cleaner                      66             1.5            181               1.0
Dishwasher                          17             5               147               8
Clothes Washer                      65              .5            183               1
Electric Food Mixer                 59             0.15           163               0.10
Electric Can Opener                 31             0.03            86               0.02
Electric Knife                      80             0.02            80               0.01

Group  III: Noisy
Small  Appliances
Sewing Machine                      36             0.25           100               0.10
Electric Shaver                     25             0.25            §0               0.10
Food Blender                        23             0.02            63               0.02
Food Disposer                       17             0.10            k6               0.05
Electric Lawn Mower                  2.0           0.50             4               0.25
Group  IV: Noisy
Electric Tools

Home Shop Tools                     13             0.10            1*0               0.10
Electric Yard Care Tools             5             0.10            10               0.10

*In millions of persons

 In hours per week

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characterized by noise levels between 60 and 70 dB(A);  (3)  Noisy
Small Appliances, characterized by noise levels between 70  and
80 d3(A); and (4) Noisy Electric Tools,  characterized by noise
levels in excess of 80 dB(A).

     Group I:  Quiet Major Equipment and Appliances
     Group I contains the noise sources  to which people are ex-
posed for the greatest lengths of time in the home environment.
Most building climate-control equipment, food-refrigeration appli-
ances, and clothes dryers fall into this category.  In view of
the widespread distribution of equipment in Group I, it is  indeed
fortunate that this equipment is among the least noisy in the
home.
     In general, due to the low levels of noise produced by equip-
ment and appliances in Group I, effects of exposure are either
negligible or mild.  Noise sources in Group I present no appre-
ciable risk of hearing damage under conventional operating con-
ditions.  Under  certain conditions, however, these noise sources
can affect sleep.  Of the noisier sources in Group I, only fans
and air conditioners are likely to be present in sleeping quar-
ters at night.   These devices are characterized by nearly steady—
state spectra because of their continuous operation.  Differences
in levels among  operating cycles are small, so that peak noise
Bevels are usually within a few dB of average  levels.   As such,
these devices may delay the onset of sleep, but are unlikely to
awaken many people.  They may, in fact, facilitate sleep for
those directly exposed to their noise,  since they  function as
sources of masking noise which can suppress interference from
other sources.
                                Ill

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     The major effect of exposure to noise from Group I  equipment
is speech interference.   Conversations in the immediate  vicinity
of the noisier sources of Group I would have to be conducted in
somewhat higher than normal levels,  or at slightly shorter than
normal speaking distances.
     The annoyance value of exposure to noise from Group I appli-
ances is also minimal.  The steady-state nature of their amplitude
and frequently spectra are highly conducive to rapid habituation.
Only rarely does one become sufficiently aware of refrigerator
noise, for example, to become annoyed by it.  Indeed, it is the
noise sources of Group I which define the background noise en-
vironment of many homes.
     Exposure to Group I noise sources has little or no  bearing
on startle and stress.  Very few people are startled by  the noise
of their air conditioners or feel menaced by the implications of
their regrigerator's whirring.
     Considering the mild nature of most of the effects  of expo-
sure to noise from Group I sources,  noise reduction is not an
urgent need.  Many appliances in Group I already operate at or
near the level of background noise in the home, so that  submerg-
ing them further into the background noise environment would
serve little purpose.  Those few noise sources in Group  I which
do produce noise levels appreciably above background levels could
probably profit greatly from approximately 10 dB(A) of quieting.
Such noise reduction, well within the capabilities of existing
technology, would alleviate the undesirable effects of noise ex-
posure from this group of appliances.
                                112

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     Group II:  Quiet Equipment and Small Appliances
     Most of the noise sources of Group II are found  in many
American homes, although not all of the sources are as  common  as
the major equipment and appliances of Group I.  Noise levels in
Group II are sufficiently elevated to render certain  appreciable
effects, particularly speech interference and annoyance.   For-
tunately, the typical pattern of exposure is an infrequent, brief
encounter.
     Of the three major effects by which noise impact is gauged
in this report, noise sources in Group II produce only  speech
interference in significant measure.  Hearing-damage risk is
negligible, both for operators and for others who may experience
secondary exposure.  Since most of the appliances in this group
require an operator, sleep interference is not a serious conse-
quence of primary exposure.  Secondary exposure probably affects
daytime sleeping to some slight extent.  Secondary exposure to
plumbing noise in multi-unit residences could conceivably awaken
as many as 35$ of sleepers, although habituation probably reduces
the percentage dramatically.
     Operators of the appliances in Group II would find speech
communication during operation quite difficult; conversations
would have to be conducted with significantly greater than normal
vocal effort or at very short ranges, and the intelligibility  of
fixed level speech (such as radio or television) would become
marginal.  The obvious mitigating circumstances, however, is the
Brevity of noise exposure typical of this group of appliances.
in practical terms, the most likely consequence of exposure to
this sort of short duration appliance noise is a temporary inter-
ruption of conversation.
                               113

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     Annoyance is the most significant of the indirect consequences
of exposure to noise from Group II appliances.  While the opera-
tor may be summarily annoyed by the brief speech interference ef-
fects, people experiencing secondary exposure may be equally, if
not more, annoyed.  The annoyance of these people (such as neigh-
bors in multi-unit residences or other family members in differ-
ent rooms) is conditioned in part by the intrusive nature of the
exposure and in part by feelings of lack of control of the noise
source.  Peelings of helplessness, exasperation, or frustration
are themselves unpleasant and can produce further annoyance.
Should secondary exposure become unduly or unreasonably common,
physiological stress from emotional arousal might develop.
     Primary exposure to the noise of these appliances is not
likely to result in much task interference.  This is true simply
because it is the undemanding and highly practiced task at hand
that is generating the noise.  Exposure to appliance noise for
people other than the operator could interfere with certain
highly sensitive tasks.  Generally, however, considering the
usual brevity of exposure, such task interference would be the
exception rather than the rule.
     A 10 dB(A) reduction of noise levels produced by appliances
of Group II would be a useful and worthwhile endeavor.  Many of
the effects of secondary exposure would become negligible, while
the speech interference effects for the operator would be con-
siderably reduced.  It is clear from Table XXVII that the single
most common source of noise exposure in .the home is plumbing.
Better design of plumbing fixtures would have a gradual but
significant effect in making multifamily residences less noisy.
Sales resistance to less noisy products (including, the much-
discussed "quiet vacuum cleaner") may be expected to diminish
as the public becomes more noise conscious.

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     Group III:  Noisy Small Applianaes
     The distribution and exposure patterns  of noise  sources  in
Group III continue the trend observed in Group II.  Group  III
appliances are found in fewer homes than the appliances  of the
preceding group.   Exposure to their noise is for equally brief
periods at long intervals.  Both of these factors tend to  moder-
ate the impact of the relatively high-level  noise developed by
these appliances.
     Hearing-damage risk can no longer be dismissed as of  minor
importance for this group of noise sources.   While it is true
that average exposure is measured in fractions of hours per week,
it is very likely that certain elements of the population  are ex-
posed to one or another of Group III source  for prolonged  periods
of time.  Home seamstresses, for example, could easily be  exposed
to several hours of sewing machine noise daily.  Yard care spe-
cialists might be exposed to equivalent amounts of lawn mower
noise.  Although even these exposure durations would not consti-
tute an imminent hazard to hearing (in the sense that they would
be unlikely to lead to sizeable permanent threshold shifts for
many years), they would nevertheless hasten eventual hearing
damage in the context of cumulative exposure  from many sources.
jn Miller's [Jff] terminology, noise sources in Group III would
be rated "yellow" (cautionary) with respect to hearing-damage
risk.
     Speech interference  is severe.  Operators receiving primary
exposure to noise sources of Group III would  not attempt conver-
sation during  the brief periods in which the  appliances are  used,
although communication by shouting would still be possible.  Sec-
ondary exposure  to  the noise of Group III sources would also
interfere somewhat  with verbal  communication.  The-principal
                                115

-------
 form of interference,  however, would be  degradation of speech
 intelligibility  rather than more  severe  disruptions of conversa-
 tion.
      Since  appliances  of Group III require operators, sleep in-
 terference  effects  of  primary exposure to their noise are negli-
 gible.   Sleep  interference effects of secondary exposure to this
set of appliance noises also tend to  be  low,  both because the
noise exposure often occurs during hours  during which  sleep is
uncommon and because the very  brief periods  of exposure  occur
only infrequently.   Of course,  the tendency  for more mothers to
be employed outside the home during the  day  constrains their use
of appliances to evening hours,  when  the  attendant noise  levels
may interfere with  family social  activities  and the sleep of
young children.
     Annoyance is once  again the  chief  indirect effect of expo-
 sure to  noise  from  Group III sources.  The operator himself may
 find the noise signature of the appliance unpleasant,  particu-
 larly if it  contains pure tone components or a highly variable
 temporal distribution  of levels.  Secondary exposure to these
 noises is also likely  to be annoying, particularly if the people
 exposed  to the noise feel that they are deriving none of the
 benefits of  the appliance's use.
     Task interference, startle, and stress reactions  are all
 plausible consequencies of exposure to this sort of noise.  As
 usual, however, difficulties in assessing the unexpectedness of
the intruding signal or the nature of background activity make
precise  prediction of  the magnitude of these effects impractical.
     Reduction of noise produced by appliances of Group III could
substantially reduce the levels of hearing-damage risk and
speech interference.  The operator's annoyance with the noise
signature of an appliance could also be affected by noise reduc-
                                116

-------
tion, but special attention would have to be paid to the spectral
characteristics of the appliance.  All of the effects of secondary
exposure to noise from this appliance group would be significantly
lessened by a 10 dB(A) reduction of noise output levels.

     Group IV:  Noisy Electric Tools
     Group IV contains the appliances which produce the  highest
levels of noise exposure in the home environment.  Considering
the potentially serious effects of exposure to such levels,  it
is fortunate that the distribution of sources is quite restricted.
As may be seen from Table XXVII, only about 250,000 electric
yard care tools have been sold, and only about 12 million elec-
tric shop tools are in use.  Further, the use of such tools  is
probably concentrated in nonurban areas where secondary exposure
effects are not as widespread as they might be in multi-unit
residences.
     Hearing-damage risk can be great if exposure to the noise
levels of Group IV sources is habitual or prolonged.  Hobbyists
who engage in regular use of power tools are likely to receive
considerably more than the average six minutes per week exposure
noted in Table XXVII.  Many such tools (saws, drills, routers,
etc.) are operated within a few feet of the user's ear, making
hearing.-damage risk even more probable.  In Miller's (1971)
terminology, such tools can produce "orange" or even "red" hear-
ing damage risk if exposure is prolonged.  It is doubtful that
any major risk of hearing damage is encountered in secondary
exposure, owing to the much lower levels experienced.
     Speech interference effects of exposure to noise of Group
IV sources can be of sufficient magnitude to preclude verbal
communication in any form other than shouting directly  into the
                               117

-------
oar.  Even the speech interference effects of secondary exposure
can be great enough to require conversation to be conducted at
nigh levels of vocal effort or at very short distances.  As was
pointed out earlier, however, relatively few people are affected
by such secondary exposure, and those who are affected are ex-
posed for very brief intervals.
     Sleep interference effects of exposure to Group IV sources
would be quite serious were the hours of use of Group IV appli-
ances to coincide with hours of attempted sleep.  Primary expo-
sure, of course, is not a problem here, but even secondary expo-
sure can reach levels in the vicinity of 60 to 70 dB(A).  Data
from the Wilson report [2£] may be interpreted as predicting that
such levels will awaken one-half of all sleepers and about one-
third of all people would find it difficult to fall asleep.  Use
of electric yard care tools at night is unlikely, but home shoo
tools are often used at night.
     To the extent that noise exposure to such high levels is
perceived as avoidable or unnecessary, annoyance effects are
probably quite pronounced.  A neighbor's noise, particularly at
such high levels, is rarely welcome.  The high noise levels pro-
duced by these tools may also interfere with the very tasks the
operators are attempting to accomplish.  If noise levels are
sufficiently high to mask warning signals or other unexpected
acoustic signs of danger, the safety of the operator and his
efficiency may be compromised.  Stress produced through prolonged
exposure to noise levels characteristic of Group IV tools may be
appreciable, particularly if exposure is involuntary.
     Considering the seriousness of the effects of exposure to
noise of appliances in Group IV, application of noise reduction
techniques is urgently needed.  Reduction of noise levels by as
                               118

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little as 10 dB(A) would have' immediate benefits in reducing the
hearing-damage risk to the operator and reduction of the speech
interference and annoyance-related effects for those receiving
secondary exposure.

     Summary of Effects of Appliance Noise on People
     Tables XXVI and.XXVII summarize the impact of appliance noise
on people in concise terms.  Table XXVII contains an account of
the extent and duration of noise exposure from all four appliance
groups in terms of millions of person-hours per week.  The reader
is reminded of the cautions expressed in the summary of Sec. 3-2.1
for the interpretations of figures expressed in person-hours.
Table XXVIII relates person-hours of exposure directly to the ma-
jor criteria of Sec. 3.1.

3.4  Projections of Construction and Appliance Noise to
     the Year 2000
     Projecting conditions to the year 2000 involves a number of
uncertainties.  One of these is the exponential rate at which
technology is evolving and affecting society.  As pointed out by
Sir Arthur Clark*, life in the year 2001 will be as different
from the present as the present is from 1890.  Who - in 1890 -
could have realized the impact that electricity and the automo-
bile would have both on life style and on the environment?  Tech-
nological innovation, however, is not the only factor to be con-
sidered.  One simply cannot account for future changes in social
attitudes.  Although a few far-sighted technologists may have
predicted in 19^0  the capability to transport passengers at
*Lecture to the Arlington Library Association, Arlington, Mass.
  (Sept. 1970).
                                119

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           TABLE XXVIII.  ORDER-OF-MA6NITUDE  ESTIMATES  OF  EXPOSURE  TO  HOME  APPLIANCE AND

              BUILDING EQUIPMENT NOISE EXPRESSED  IN MILLIONS  OF  PERSON-HOURS  PER  WEEK
Noise Source
Group I: Quiet Major Equip-
ment and Appl iances
Fans
Air Conditioner
Clothes Dryer
Humidifier
Freezer
Refrigerator
Group II: Quiet Equipment
and Small Appliances
Plumbing (Faucets, Toilets)
Dishwasher
Vacuum Cleaner
Electric Food Mixer
Clothes Washer
Electric Can Opener
Electric Knife
Group III: Noisy Small
Appl i ances
Sewing Machine
Electric Shaver
Food Blender
Electric Lawn Mower
Food Disposer
Group IV: Noisy Electric
Tools
Home Shop Tools
Electric Yard Care Tools
Speech Interference*
Moderate Severe
(45-60) (>60)


1200
242
94
10
0
0


535
461
280
222
215
117
1


19
6
2
1
0.5


5
1.5
Sleep Interference*
SI i ght Moderate
(35-50) (50-70)


0
121
10
15
0
0


267
4
0.5
1
0.5
0.2
0.1


0.5
1
0.2
1
0.5


2
.1
Hearing Damage Risk
Sliqht Moderate
(70-80) (80-90)


0
0
0
0
0
0


0
0
0
0
0
0
0


9
5
0.5
0.3
0.5


1
0.4
r\j
o
    *These figures are not directly  Interpretable  in  terms  of person-hours of lost sleep or
     speech irat er"f er-enc e  (see text) .

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supersonic speeds, it is doubtful that they  could  have  predicted
that such a technologically feasible system  would  be  abandonded
largely because it was expected to make too  much noise.
     Although any long-term predictions are  fraught with such
difficulties, one can still make educated guesses  with  a reason-
able level of confidence.  Rather than merely extrapolate exist-
ing conditions to the indefinite future, we  try to be somewhat
quantitative by projecting the impact of construction and appli-
ance noise on the basis of existing forecasts of population,
family size, gross national product, and trends toward  urbaniza-
tion.  Construction activities will continue to follow such
growth patterns, although the character of construction may
change significantly with greater use of prefabricated materials
and the introduction of new kinds of equipment.  Similarly,
ownership of appliances has been found to be a function of family
income level, and we use their relationship  to project the growth
of appliance use in the generally more affluent households pre-
dicted for the year 2000.  Also, rather than trying to account
for conflicting trends and changing attitudes, we  project the
extent of exposure with the assumption of no change in noise
level for a given equipment or appliance type and consider only
major trends that can be easily  identified.
     We use the following data,  taken  from the U.S. Census Bureau,
for projecting the increase in exposure to construction and appli-
ance noise:
                                          1970       2000
GNP  (billions of  1958  dollars)           720       2240
Total Population  (millions)              200         293
Total Number  of Households  (millions)     63         104
people per  Household                        3-17        2.8
                                121

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3.4.1  Construction activity
     Given the predicted increase in population and in financial
resources, one can expect fairly extensive building activity.
However, the urban areas have limited space available for new
building; thus, the trend is for areas outside those now identi-
fied as central cities to become urbanized.  Figure 24 illus-
trates this trend for single-family, multi-family, and nonresi-
dential construction activities.  With available land becoming
more and more scarce within the central city, the building of
single-family and multi-family dwellings will continue to de-
crease sharply.  In 2000, we can expect to find approximately
one-third the number of residential construction sites as were
active in 1970.  Nonresidential building is expected to increase.
In areas outside the central cities, both residential and
nonresidential construction should increase significantly.  Non-
residential building activity is expected to increase by over 50J5
as the present suburbs become urbanized.  With this general trend
in mind, we use the data given above to project the expected in-
crease in exposure to noise from construction activities.

     Nonresidential
     We assume that the level of nonresidential construction ac-
tivity in any given year is proportional to the real Gross Na-
tional Product (GNP) for that year.  To find the nonresidential
construction activity for any particular year, the ratio of the
GNP for that year to the 1970 GNP is multiplied by the number of
nonresidential sites built in 1970 (Table X).  The resulting
total construction figures are apportioned between "central cit-
ies" and "other metropolitan areas" in the same proportions as
occurred in 1970.  Despite the expected decrease in total con-
                               122

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    1970
             1980                1990
                  CENTRAL  CITY
                                                              2000
          NONRESIDENTIAL
                         777 SINGLE FAMILY
   1970
FIG.  24.
             1980                1990
           OUTSIDE OF CENTRAL  CITIES
NUMBER  OF  BUILDING CONSTRUCTION SITES PROJECTED TO  THE
YEAR 2000.
                    123
                                                              2000

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struction site within the central city, nonresidential sites are
expected to increase.

     Residential 1
     We assume that the population and population density of
central cities will remain at their present levels until the
year 2000, and that most residential construction in central
cities will be for the purpose of replacing decayed units rather
than for housing new population.  The number of construction
sites will decrease due to the established trend toward an in-
creasing population of multi-family dwellings over single-family
dwellings.  (Two- to four-family houses, which represent a
negligible fraction of total construction, are here included in
the total for single-family housing.)
     For metropolitan areas other than suburbs, the number of
units constructed in any one year is assumed to be proportional
to the population increase in the previous ten years.  To esti-
mate this increase, we project the total metropolitan population
by multiplying the projected total national population by the
estimated proportion of the population living in metropolitan
areas.  All the increase in metropolitan areas population for a
particular year is ascribed to noncentral city areas.

     Roads
     A simple but plausible indication of road construction ac-
tivity, is the population level.  Clearly additional people will
require additional roads, the capability of rapid transit being
small at present.  However, the urban areas have limited space
for new roads, and urban residents are expressing increasing
opposition to new road construction on grounds of aesthetics,

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pollution, and the community dismemberment concomitant  with  the
installation of limited access highways.   Thus,  it would  seem
unlikely that road construction will rise as fast  as  other mea-
sures such as the GNP.  We therefore project the future level  by
multiplying the present level of activity by the ratio  of the
projected population divided by the current population.
     The number of people affected by construction sites  is  com-
puted in the manner described in Sec. 3.2.1.  Population densi-
ties for all metropolitan areas are assumed to be  constant with
time - ^500 people/sq mi for central cities and 2^00  people/sq mi
for other metropolitan areas.  At any one site,  people  are appor-
tioned to specific transmission loss intervals according to  the
method shown in Pig. 20.  The resulting exposure to construction
noise is given in Fig. 25 in person-hours.  In this figure,  multi-
family residential construction has been included with  nonresidential
construction, since these types of building activities  are quite
similar.  Note that the number of people exposed to noise from
single-family dwelling construction declines steadily with time.
This trend is more than compensated for by the rapid increase in
nonresidential and multi-family sites — for which the duration
of construction is typically six times greater than the duration
for single-family houses.  Thus, the number of person-hours  of
exposure is expected to increase by about  5Q% in the next 30 years.

3.4.2  Appli ance use
     We assume that the probability of future appliance owner-
ship as a function of income level will remain the same and that
appliance costs will remain approximately  the same in  current
dollars.  With these assumptions in mind,  we base our approxima-
tion of appliance use on projected population, family  income,
                               125

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      o
      2
      O
      o
      cn
      CO


      Q
      LJ
      M
      OC.

      O
      UJ
      QC
      o
      a.
      x
      UJ
      in
      oc.
      ^
      O
      I

      z
      o
      (O
      a:
      UJ
      a.
NONRESIDENTIAL AND

MULTIFAMILY  RESIDENTIAL
                TOTAL

                CONSTRUCTION
                                       ROAD CONSTRUCTION
  SINGLE FAMILY  RESIDENTIAL
                                                             2000
FIG.  25.   PROJECTED  CHANGE  IN  EXPOSURE TO CONSTRUCTION NOISE,

          ASSUMING  NO  CHANGE  IN  NOISE LEVELS.
                              126

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and income distribution.  This estimation is likely conservative
as some appliances are continuing to increase their acceptance
in all income levels, although their growth of acceptance is  low
at the higher income levels where some appliances have nearly
saturated the market.  For those appliances for which insuffi-
cient information is available on appliance possession at the
various income levels to make the projection described above,
v?e estimate future possession from current marketing information
on percentage of replacement sales and on market penetration.
     In projecting future impact, we estimate that the appliance
usage will remain approximately at current levels.  Supporting
this assumption is the little deviation shown in average time
spent by homemakers over the last forty years.
     Figure 26 illustrates the increase in exposure to appliance
noise by plotting hearing-damage risk and speech and sleep
interference in person-hours of exposure.  As explained in Sec.
3.1, these three effects are among the most salient and tangible
consequencies of noise exposure and thus can be most readily
interpreted in nontechnical terms.  As can be seen on Fig. 26,
we project that number of person hours during which people will
be exposed to the risk of hearing damage will 'more than double
in the next thirty years, as will the number of person-hours dur-
ing which normal conversation will be difficult and people will
be either awakened or prevented from falling asleep.
     As explained previously, we have not taken into account cer-
tain trends, discussed in  Sec. 4, which are having some effect
on the noise levels produced by construction equipment and appli-
ances.  However, one should note, when reviewing these projec-
tions, that industries are becoming sensitive to a growing con-
cern about noise pollution among the general population.  For
                               12?

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         3.0
      CO
      z
      o
      o
      o
      UJ
      cr
      ^
      CO
      O
      Q.
      X
      UJ
      CO
      or
      =>
      o
      I
      o
      CO
      cr
      UJ
      Q.
         2.5
      00

      Q
      UJ
      N
         2.0
      cr
      o
1.5
l.o
         0.5
          1970
           HEARING DAMAGE RISK
                                     SPEECH AND  SLEEP
                                     INTERFERENCE
                   1980
1990
2000
                                     YEAR
FIG.   26-.  PROJECTED CHANGE  IN  EXPOSURE  TO APPLIANCE NOISE,

          ASSUMING NO CHANGE  IN  NOISE  LEVELS.
                               128

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example, construction equipment has become noisier as it has
become more powerful; yet, one manufacturer has developed and is
marketing a quiet air compressor.  Conversely, refrigerators  and
air conditioners have become noisier as manufacturers have strived
to meet market-place demands for extra features and smaller size.
Thus, rather than try to account for an infinite number of vari-
ables, we have assumed no change in noise levels for both con-
struction equipment and appliances.  We feel that this method
has resulted in reasonable near-term projections, if no noise
control action is taken.
                                129

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4.  INDUSTRY EFFORTS
4.1  Introduction
     Efforts by industry to quiet products are usually
motivated by two factors:  market place demand and government
regulation.  The consumer can exert pressure on industry by
electing to buy or not to buy or by selecting a competitive
brand that produces less annoying noise levels.  This kind of
"consumer regulation" can be very effective — particularly
with regard to appliances — in that manufacturers are quick to
respond to consumer tastes.  However, consumer pressure can
also subvert efforts a manufacturer may wish to make; for
example, housewives often associate the noise produced by a
vacuum cleaner with its ability to clean - the noisier the
machine, the more satisfied a homemaker may be with its
performance.  In any event, the purchaser can apply direct
pressure to the industry.
     Public pressure, on the other hand, is usually very
ineffective.  The only recourse for people who do not own the
noise sources to which they are exposed is to register a
complaint.  Such complaints have no effect whatsoever unless
enough exposed people organize and concentrate their efforts on
a particular source.  This kind of community response may
eventually result in government regulation.
     Our analysis of industry efforts to quiet construction
equipment, appliances, and building equipment was organized as
follows:

   • We constructed a matrix of common products and
     significant manufacturers.
                               130

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    •  We rank-ordered  products  as  to  approximate magnitude
      of noise  impact  or  need  for  quieting.
    •  We rank-ordered  manufacturers as  to  their importance
      in the  product area.
    •  We examined  the  resulting manufacturer/product
      "intersections"  with  a view  toward organizing a
      number  of interviews  that would cover  important
      products  and leading  firms and  still be within the
      time  and  effort  constraints  of  the study.
    •  We developed an  extensive interview  format both to
      guide the interview and  to provide a standardized
      method  of reporting.   (Full  use of this format was
      not possible within the  constraints  of this  study;
      it could  be  useful, however, in the  event that in-
      dustry  efforts are  to be  examined in more detail.)
    •  Under guidance of the format developed, we collected
      subjective data  and objective observations;  this in-
      formation forms  the basis for representative general-
      izations  cited in this report.
      As  expected,  the industry is concerned about releasing
data  which might  disclose proprietary  ideas or expose a com-
petitively sensitive  area of operations.  Accordingly, identity
of sources is  carefully  safeguarded herein.  This need for
corporate security has limited our collection of  statistically
meaningful data;  the  trends observed,  however, are clear and,
   themselves, undoubtedly represent the  noise control environ-
      in industry.
                                131

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4.2  Construction Industry Efforts
     We view the construction industry as consisting of two
major sectors:  equipment manufacturing and equipment operation
(i.e., building construction).  The functions of these two
sectors of the industry are so different as to warrant separate
discussion.

4.2.1  Equipment operation
     Section 3-2 describes this sector of the construction
industry in detail, identifying types and phases of site activity
and describing the areas in which noise abatement can be
achieved.
     The industry has, in fact, done almost nothing to quiet
site operations.  Its attitude may be attributed in part to the
fact that quiet equipment has not yet been made available on a
cost-effective basis; however, a limited capability does exist
for quieting a site by relocating or rescheduling equipment.
This sector has not exercised its influence as a "consumer" to
bring pressure to bear on the equipment manufacturers, nor has
it responded to public complaints.  Hence, regulatory measures
may be the only solution to the problem of construction site
noise, and such regulations are imminent.

4.2.2  Equipment manufacturers
     There are approximately 2000 manufacturers* of construction
equipment in the U.S.  In total, these companies offer about
200 different products.   For the purposes of assessing the state
of noise control in this sector of the construction industry, we
*Defined by counting separately certain divisions of larger
 firms which have a highly identifiable product line.
                                132

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categorized 48 general types of products that are potentially

significant noise sources.  We group these product types into

three orders of classification:  (1) class of noise problem

anticipated, (2) relation of equipment to function at the site,

and (3) specific equipment names.

   I.  Engines and power trains

       A.  Excavating equipment

           1.  backhoes
           2.  clamshells
           3.  dozers
           4.  draglines
           5.  loaders
           6.  rippers
           7.  (power) shovels

       B.  Highway equipment

           1.  compacters
           2.  graders
           3.  pavers
           4.  pipe layers
           5.  pulverizer/mixers
           6.  rollers
           7.  rotary borers and drills
           8.  scrapers
           9.  street sweepers
          10.  trenchers and backfillers

       C.  Equipment to handle finished materials

           1.  cranes
           2.  fork (and similar) lifts
           3.  travel lifts

       D.  Mobile units

           1.  tractors, crawler
           2.  tractors, wheel
           3.  trucks

       E.  Power supplies

           1.  compressors
           2.  electric-power generators
                                133

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 II.   Interaction between equipment  and materials  (may
      include  engines and power  trains)

      A.   Equipment  to  handle  bulk materials

          1.   bins  (and hoppers)
          2.   concrete  mixers
          3.   conveyors

      B.   Large  impact  tools

          1.   drop  hammers
          2.   pile  drivers

      C.   Medium impact tools

          1.   jack  hammers
          2.   rock  (vibrating) drills

      D.   Small  impact  tools  (power)

          1.   impact hammers
          2.   impact wrenches
          3.   riveters
          4.   stud  drivers

      E.   Rotary tools

          1.   bench drills
          2.   grinders
          3.   hand  drills
          4.   hand  saws
          5.   table saws

III.   Miscellaneous (may include sources characteristic of
      I and II above)

      A.   Pumps
          1.   concrete  pumps
          2.   stripping pumps
          3.   well-point pumps

      B.   Other
          1.   burners  and heaters
          2.   sand blasters
          3.   screeds
          4.   concrete vibrators
                             134

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     Two assumptions underlie the terminology selected:
(1) equipment in transit under its own power is a truck  or
tractor, even though when working it may be a dozer or a crane,
and (2) classification by function at the site is arbitrary
since many types of equipment have several uses.
     Manufacturers of construction equipment can be classified
according to size/type of equipment produced as

   • large companies producing large volumes of essentially
     similar, large items of machinery;
   • medium-size companies producing "customized" pro-
     duction runs of more limited numbers, usually of
     smaller machinery; and
   • manufacturers of power hand tools and pneumatic
     equipment.

     Our interview program was organized to  cover the two major
acoustic source types  (prime-movers and power  trains) and the
forty-eight  types of products and three classes of companies
identified above.  We concentrated our efforts  on significant
leaders in the industry and companies producing a wide  variety
of products  that have high levels of noise output:

   . Of the  ten manufacturers intensively  interviewed,
     about eighty product analyses resulted.
   . Eight of the firms produced equipment in  which the
     prime-mover or power train  is a significant  source
     of noise; two  companies  produced only power  hand
     tools.
                                135

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    • Three companies were high-production manufacturers;
     seven manufactured customized equipment.
    • Three-quarters of all the products where subjected
     to specific analysis, covering all significant noise
     sources except impact tools and pumps.
    • The ten firms represent a significant part of the
     industry:  Of the two thousand firms nominally in
     the industry, about twenty comprise the industry
     "core".  Eight of the ten interviewed are part of
     this core.

     Our overview of the equipment manufacturing industry showed
that:

     1.  Large companies closely resemble the Detroit assembly-
line manufacturing concept.  They tend to have large engineering
staffs and are quite advanced in their efforts toward developing
quieter products.  They are aware of the competitive advantage
of quieting equipment but are also sensitive to price competi-
tion from smaller companies and foreign manufacturers.
     2.  Medium-size companies producing "customized" items
tend to feel more keenly the competitive pressures of the
market place.  Competition comes not only from domestic and
foreign companies but also from other types of equipment that
can perform the same operation.  Engineering staffs tend to be
small and product-oriented, interested only in improvements
that incorporate new technology (e.g., hydraulic vs mechanical
drive).  Little effort has been made toward quieting products,
with pressures of current and planned noise control legislation
being passed on to their suppliers.  They generally have no
plans or see no need for developing greater noise control
technology.
                               136

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     3.  Manufacturers of hand power tools and pneumatic
equipment fall Into two categories:   Large multiproduct com-
panies which tend to mount considerable R&D efforts and smaller
companies which are not so innovative but which do follow trends
developed by the larger companies.  Noise control has been
pursued rather vigorously by these larger companies as part of
their product improvement programs,  but effective quieting of
hand tools is difficult because of such practical constraints
as size and weight.

     Our in-depth interviews revealed that in the past the
industry's concern with noi.se problems has been directed pri-
marily to protection of the equipment operator.  The impetus
for this concern came largely from noise codes imposed by
foreign countries, where some U.S. equipment has had to be
itreworked" by foreign distributors.   Three of the eight "large
equipment" companies interviewed had previously quieted equip-
ment to enter European markets.  Switzerland and Belgium,  for  ex-
ofliple, specify permissible noise levels  for such machinery;  in
addition, foreign manufacturers make quieter machines  and  set
a competitive pace in foreign markets.   American manufacturers
seem to have met this competition by custom-designing  equipment
for export.  There is an implication here, of course,  that
many American machines marketed abroad have been quieter than
counterparts that were marketed domestically; however, this
^plication has not been verified by this  study.
     Half the companies interviewed are  currently undertaking
nrograms to quiet their products  for the  domestic market for the
•first  time.  Many of the present programs  have been  started  this
 &st year and are aimed primarily.at protecting  operators,  so  as
f-o conform to impending legislation/regulation regarding occupa-
tional health and safety.  Only one of the companies indicated
                                137

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that purchasers complain about protection for operators on their
own initiative, and only one case emerged where a union had
lodged a formal complaint.  Six of the eight companies described
pressures on behalf of operators that originated with existing
or proposed governmental action.
     Many manufacturers feel that the efforts they are now
making on behalf of equipment operators will pay off in meeting
future noise limits designed to protect the public.  Perhaps,
one of the most promising future approaches has been taken by
one of the manufacturers of large equipment, who has charged
design teams with the responsibility of integrating noise control
into the overall design of his next generation of products and
has set up review boards to evaluate new designs from all stand-
points, including noise.
     Pour of the eight companies specifically mentioned the
recently enacted Chicago noise ordinance as contributing to
their specific future objectives.  The industry generally anti-
cipates EPA-administered federal control; the visits of our
interviewers reinforced this feeling.  Two companies believe
that pressures for quieting will increase with time — apparently
as a result of an increasing public awareness of noise as an
environmental pollutant.
     Although the industry has become increasingly aware of the
pressures for noise control and has already made some efforts
in this area, manufacturers must' cope with economic pressures
that argue against noise abatement.  Some companies feel that
the intensity of competition sets the limits on what price the
market will bear.   One of the industry's leaders was concerned
that purchasers will continue using old equipment if prices
rise significantly.  Other industry leaders point out that
foreign-made machines (some of them already quieted) will enter
                                138

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the American market if prices rise appreciably.   One company
predicted that a small rise in the price of truck-mounted con-
crete mixers would lead to the introduction of alternative
methods for handling concrete delivery and production.
     Companies who feel that the demand for their products is
great enough plan to pass quieting costs onto the consumer,
although such threats as foreign competition and alternative
methods put limits on this process.  The question here is how
fast the industry dares to move.  One limit on rapid movement
j_s price competition.  One company may be able to beat its com-
petitors to the market with a quiet machine, but it does not
dare raise prices substantially in the face of competition.
pifferent companies approach this problem differently.  Most
express the intention to meet or exceed the competition, but
they feel that any great competitive advantage they gain
through an all-out effort to quiet their products would be short-
jived.  One company sees its competition as being extremely
severe, and fears that it may not be prepared for the next round
of quieting, while another company has actively  launched a pro-
gram designed to produce quieter machines than its  competitors
at lower costs than the competitor will incur.
     This company and some others expressed the  concern that
often accompanies any industry  leadership; i.e., a  company may
invest large sums in quieting which will thus increase the cost
Of products, while another company that refuses  to  quiet  pro-
ducts keeps it prices low and may  successfully challenge  noise
regulation in the courts.
                                139

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     While all companies regard cost as an immediate — and
perhaps as the ultimate — constraint, two other constraints
become paramount if and as costs diminish:  time and technology.
Three companies, each in a different fashion, represented that
costs can be traded for development time; i.e., more time for
development would reduce the cost of competition, allowing
quieting techniques to be integrated into planned engineering
efforts and to be an integral part of the seasonal progression
of models.  The very company that is setting out to achieve the
most quieting for the least cost is the one that feels that
technology will eventually supercede cost as the principal
factor that limits quieter equipment.
     At another firm, the technical limitations are spelled out
in terms of:  (1) loss of equipment power through increased
muffling; (2) increase in the difficulties and cost of main-
tenance; (3) fire hazards through using insulating materials
that can become oil-soaked; (4) unsafe operation by suppressing
or distorting the noise "signals" upon which operators depend
for safety; and (5) ineffective operation, by disturbing these
same "signals", thus hindering the ability of the operator to
tell how effectively he is operating.
     The industry also voiced concern over the feasibility of
noise abatement where equipment and materials being worked
interact to become prominent sources of noise; e.g., concrete
mixers (where the structure may be the noise radiator); jack
hammers (where the tool and its driving media may be the
offender); riveters (where the structure of the building may be
the primary source); and pile drivers (where both the structure
and the media may be significant sources).  This "interaction"
type noise source may be very difficult to quiet.
                               140

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     However, no firm interviewed condemned noise limits  out-of-
hand, nor did they deny their inevitability.  Six of the  eight
companies expressed the opinion that unless they quieted  their
products, their markets would disappear.   Peelings varied from
acceptance of inevitable reality to enthusiastic approval of the
trend.
     During the course of this study, members of the BBN  team
ivere actively engaged in the regulatory efforts of three  cities
and one state — Boston, Chicago, San Francisco, and Illinois.
This work provided an insight into the mechanism of regulatory
control from outside the construction industry.  In addition,
discussions were held with the Construction Industry Manufac-
turer's Association (CIMA) to obtain information about controls
within the industry.
     There are potentially four levels of regulatory bodies
outside the industry:  federal, state, city/town, and
specialized local departments (city departments of health, air
pollution control, zoning/building, etc.).  The regulatory power
exercised by these bodies is generally graduated into four steps:
general standards (setting goals), enabling powers  (granting
power to a lower body), specific regulations  (against which are
judged infractions), and procedures  (for measuring performance).
     The target of the regulatory powers is either basic
equipment performance  (i.e., noise of new equipment as sold by
manufacturer) or equipment operation'(e.g., total noise emitted
from a site).  Regulations are usually aimed  toward protecting
/^) health  (as in the hearing-protection section of the Federal
public Contracts Act) and  (2) environmental quality  (as in the
construction site operating  limits proposed for  the city  of
goston).

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     No fixed pattern has yet emerged which Interrelates the
regulatory bodies, nature of powers, targets, or degree of
protection.  Current activity at all levels, however, has
alerted the industry that controls are imminent.  One signifi-
cant set of controls already in existence limits the noise
from new construction equipment sold in Chicago; dual controls
are being proposed in Boston, to limit site operation noise and
to restrict noise from new equipment.  Enabling legislation
exists (as in the General Laws of the General Court of
Massachusetts), and enabling powers have been passed on through
city ordinance (again as in Boston).  Even though the Federal
Public Contracts Act does not apply to local construction, its
philosophy is impressed on the industry, and its effect is
increasingly noted in the carryover of standards into new
federal occupational health and safety legislation.
     In summary, the regulatory bodies outside the construction
industry have begun to exercise some influence in the area of
noise abatement.
     CIMA and the national standards-setting bodies of ASTM/SAE
are both actively addressing the problems of measuring equipment
noise and recommending quieting standards.  The equipment
manufacturing industry would like to coordinate its activities
with those of its closely related standards-setting bodies
(see Appendix B for discussion of a paper prepared by CIMA).
Self-regulation via industry-initiated standards is presumably
somewhat hindered by federal anti-trust provisions.
     As yet, no broad controls have been established.  It is
assumed that the example set by the City of Chicago equipment
noise ordinance will stimulate other similar action, eventually
resulting in a proliferation of standards put forth at the local
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level.  As an alternative, the industry would welcome one
comprehensive overriding standard.   However, some anxiety was
expressed as to the reasonableness  of future legislation,
specifically that sufficient time would not be allowed to con-
form to such a standard.  Typical new product lead-times are
on the order of five years.  Industry believes it could meet
noise goals without excessive cost  to the consumer, if given
enough time.
     In general, it appears that industry is aware that it will
be forced to comply with ever-tightening noise standards.  While
this fact seems to worry everyone to some extent, most manu-
facturers are confident that they will meet the limits set by
current and anticipated legislation/regulations/standards.  In
fact, all but .one of the companies interviewed stated their
noise control goals in terms of such limits, frequently  speci-
fying either the levels stated in the Walsh-Healey Public
Contracts Act for operators or those set forth by the Chicago
ordinance for public exposure.
     Early abatement efforts made by the manufacturers have been
highly successful; thus, the industry is somewhat optimistic
about its ability to cope with pressures for noise control.
However, it is important to note that the  industry has begun
vjith the most obvious and the easiest tasks  it must  accomplish.
Future tasks are apt to be far more difficult and costly;
therefore, future struggles to comply with  more  stringent
standards could possibly influence company  attitudes, making
them less receptive to  regulation.

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4.3  Building Equipment and Appliance Industry Efforts
     Throughout this study we have viewed the home appliance
industry as consisting of two major sectors:  owner-controlled
appliances and major building equipment (such as heating and
plumbing systems in multifamily dwellings).  We continue this
division, since (even though certain large companies produce
both types of equipment) the nature of the marketing and of
the pressures for noise control are quite different.

4.3.1  Building equipment
     The quieting of building equipment involves the contribu-
tions and decisions of an interdependent chain that consists of
owner, regulatory body, architect, engineer (both mechanical and
structural), equipment, and manufacturer.  For purposes of ana-
lyzing industry programs, three sectors of this network are
significant:  (1) the equipment manufacturing sector; (2) the
design sector, and (3) the control sector.
     Overall, quieting of the equipment in a building thus be-
comes a compromise between the elements of the chain on matters
of design, budget and technical performance.

     Manufacturing Sector
     Manufacturers of building environmental control and services
equipment are currently aware of the significance of quieting
their products; they realize that they have a role to play in
quieting at the source.  The manufacturer does not have complete
control over the quieting of the finished system; here, he is
dependent on the architect and the mechanical/structural engineers
as to location, local architectural treatment, and surrounding
structural design.

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     Given this ambiguity, manufacturers in the past  have been
uncertain as to what to quiet, how much to quiet,  and even how
to measure progress in quieting.  In a recent review  of a wide
variety of currently available equipment from a variety of manu-
facturers, several types of equipment showed spreads  as large
as 10 dB within the type.  However, no line of equipment from
a single manufacturer was characteristically noisy or quiet.
     Currently, manufacturers are trying to solve  problems of
rating their equipment.  This effort is being channeled largely
through the trade associations and the technical societies.
The fundamental aim of this effort is to furnish the  architect
and engineer with ratings that they can utilize in designing
their equipment layouts and in specifying their equipment.
     In the compressor industry this step has been substantially
achieved.  The result is that competitive criteria have become
clearer and that the major technical barrier to quieting is
common to the industry as a whole.  (It is the blade-rate scream
from the impeller.)  It is apparent that if a manufacturer
could make a technical breakthrough in this area,  he would
achieve a strong competitive advantage.  There is  some question,
however, as to whether any single manufacturer can afford the
development costs that such a breakthrough would entail.
     When rating methods have been developed and when, as a
result, the technical problems become better defined, manu-
facturers of building equipment will face three basic alterna-
tives in reducing the noise from their products that reaches
the building's occupant:   (1) redesign of the equipment,  (2)
enclosure of the noise source by the manufacturer and (3)
passing the problem along to the building designer.

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     Design Sector
     The mechanical engineer is starting to add acoustic per-
formance of equipment to the list of building specifications.
These specifications are passed back to equipment manufacturers.
     The mechanical and structural engineer interface with the
equipment manufacturer in the area of containment of noise vs
quieting at the source.  Trade-off between the two approaches
must be considered on both sides.  Enclosures, if chosen often
become a manufacturer's problem because of the need to bring
proper controls and services through the enclosure.
     The same two factors face each other regarding size of
equipment.  The design sector wants compact equipment in order
to increase usable space as well as be able to move through
doors, while the manufacturer tends toward larger equipment to
favor quieting.
     The architect meets the manufacturer at another interface
that concerns equipment location, local architectural treatment
and selection of structural system.  Acoustically remote spaces
are often not possible to be allotted to house equipment in
view of the high cost of building space and the attendant desire
to maximize revenue-bearing space.  Architectural taste for open-
ness in design and novel structural systems can often make the
isolation of equipment spaces more expensive.
     The designer faces a unique combination of equipment for
every structure he designs.  These combinations create unique
problems of design.  They also create unique patterns of emission,
Thus in one building, the designer may be able to afford a fairly
noisy piece of equipment because it will operate by itself or
because it will operate in relative isolation.  In another
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building he may require a very quiet piece of equipment  to perform
the same function because it may be operating alongside  other
noisy machinery or in a location that makes the building users
vulnerable.

     Control Sector
     Controls regarding building equipment acoustic performance
emanate from four sources:  (1) trade associations within the
building equipment industry; (2) specialized technical societies
also within that industry; (3) generalized professional tech-
nical societies (such as ASME, IEEE, etc.) serving all U.S.
equipment industries; and (4) regulatory bodies (Federal, state
and local).
     The role-of the trade associations is to set standards for
rating the performance of equipment and to evolve guidelines for
proper application of the equipment.  Among the most active in
dealing with noise control are:

    . Air Conditioning and Refrigeration Institute
    . Air Moving and Conditioning Association
    . Air Diffusion Council
    . Compressed Air and Gas Institute
    . American Gear Manufacturers Association
    . National Fluid Power Association
    . Hydraulic Institute
    . National Electrical Manufacturers Association

     In contrast, the technical societies  both within the  building
equipment  industry and  outside, serving all  industries,  are  dedi-
cated to developing measurement procedures and standardizing the
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techniques for making measurements and reporting results.  Most
active in the measurement area are:

   • American Society of Heating and Refrigerating and Air
     Conditioning Engineers
   • Institute of Electrical and Electronics Engineers
   • American Society of Mechanical Engineers
   • American National Standards Institute
   • American Society for Testing Materials

     Government agencies exercise control in three ways:  (1)
as regulatory agencies concerned with occupational health; (2)
again as regulatory bodies concerned with community noise; and
(3) as significant purchasers of equipment for use in public
buildings or publically financed projects.  The occupational
health and noise control aspects of the Walsh-Healey Public
Contracts Act has served as a pace-setter for establishing
targets for the building equipment industi'y, although the fed-
eral act itself generally has little direct applicability to
most of equipment currently sold.
     As state and local governments extend their protection against
occupational health hazards, they are tending to adopt the Walsh-
Healey criteria.  These enactments tend to put pressure on manu-
facturers and designers alike.  The most active current issue
arises from the establishment of a stringent specification
(80 dB(A) at three feet) by the General Services Administration
for machine noise in federal buildings.
     Manufacturers are having difficulty meeting the G.S.A.
standards through quieting at source, but G.S.A. replies that
containment will solve the problem.  In one instance, however,
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a substantial federal building project has not been able to at-
tract qualified equipment bidders.  Minimum property standards
for FHA-assisted dwelling units have been in effect for a number
of years.  Some lattitude regarding enforcement appears to be
permitted to the directors of regional offices.
     In total, the criteria for acoustic performance of building
equipment are still in a state of evolution.  More detailed dis-
cussion of standards is contained elsewhere in this report.  Mea-
surement procedures are still under development, and the current
acoustic performance of standard equipment is still not fully
understood within the various sectors of the industry.  A system
for rating equipment by category is seriously needed to give the
control sector, designer and manufacturer a common language.
The divergence of the city codes that do exist (15 dB spread)
needs to be eliminated to reduce customizing requirements on
the equipment manufacturers.

     Summary of Pressures For/Against Quieting
     a.  For
   • Quieting deemed a "necessity", no longer a "luxury"; tenants
     now in second or third generation of air conditioned buildings,
     and attitude toward quiet has matured to this point of view.
   • Architectural desire for openness of design, new  lightweight
     structural systems and economy of nonrevenue bearing space
     places premium on quieting of source.
   • Mechanical engineers increasingly aware of need for quieting,
     hence now specifying acoustical  performance.
   • Occupational health and  safety pressures  spreading,  following
     example set by Walsh-Healey  Act.

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   • Codes at city level to enhance community quiet.
   • Quieting generally becoming cost-beneficial in eyes of
     building owners.

     b.  Against
   • Technical barriers make next step too expensive  for single
     manufacturer to attempt by himself.
   • Lightweight and small equipment desired to fit into small
     allocated spaces  and remain tolerant of light foundations.
   • Specific quieting goals are not clearly set, and codes and
     regulations are confusing and contradictory.

     a.  Trade-off Must be Examined
   • Containment via enclosure vs quieting source — which is more
     cost effective?
4.3.2  Home appliances
     There are approximately 70 to 80 important manufacturers*
of home appliances in  the U.S.  These companies offer 30 to 40
different products that are potentially significant noise
sources.  For the purposes of assessing the state of noise
control within this industry, we rank-ordered specific appli-
ances according to their relative importance with regard to
noise abatement in and around the home.

   • air conditioners,
   • dishwashers,
   • water closets,
*Defined by observing company names and appliance categories in
 various well-established consumer journals.
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   •  other major appliances (clothes  washers,  dryers,
     refrigerators),  and
   •  appliances whose noise output is interpreted as  a
     measure of its efficiency (vacuum cleaners,
     blenders).

     The industry is  characterized by four major  company/product
mix categories:

   •  large, multidivisional companies producing a broad
     range of products;
   •  medium-size companies formerly specializing in a
     well-known product but now branching out to take
     advantage of a good name in the consumer market;
   •  small and medium-size firms who maintain a certain
     leadership character through continued specializa-
     tion; and
   •  companies manufacturing "private label" appliances
     to be sold by others, usually by large retailers
     who contract for and control the product policies
     oT a large volume of home appliances.

     Our interview program was organized to cover leading
manufacturers  of a range of equipment as well as retailers and
industry associations.  We interviewed eleven manufacturers
(or manufacturing divisions of large companies), two major
retailers, and  two industry associations.  Twenty-nine products
and ninety-six  product/manufacturers were  covered by this
survey.
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     Our overview of the industry's attitude toward noise
control shows it to be so direct a function of market place
pressure that noise control technology often exceeds application.
Appliance manufacturers tend to maintain sophisticated R&D and
product engineering staffs that are capable of delivering more
noise reduction than market strategy can justify.  In fact,
some companies have tried — unsuccessfully — to market quiet
products, such as air conditioners, vacuum cleaners, blenders,
and hair dryers; others have developed a number of quiet proto-
types that were not put into production.
     Consumer research shows low noise levels are not highly
valued by most customers.  Several companies keep systematic
track of customer correspondence, while the industry itself
maintains a Major Appliance Consumer Action Panel (MACAP) that
acts as a clearinghouse for complaints.  These records, all of
which concern major appliances, show relatively little com-
plaint about noise.  For example, only 5$ of the letters to
MACAP in the first eight months of 1971 were about noise.
     The objectives for quieting household appliances seem to
vary with the market pressures on particular products.  With
this observation in mind, we organize our discussion of noise
control efforts around the "problem" appliances identified
above.

     Ai?> Conditioners
     There is probably more market pressure to quiet air
conditioners than to quiet any other household appliance.  Since
air conditioners emit noise both indoors and out, they frequently
affect not only the purchaser and his family, but also neighbors
and passersby.  Both kinds of emissions generate pressures for
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noise reduction.   Pressure from neighbors takes the form of local
noise ordinances  that specify maximum sound-emission levels at a
property line; this pressure is passed on to the manufacturer,
as one company pointed out, by dealers or marketing men who are
aware of the ordinances.
     Dollar sales of room air conditioners grew almost eight-fold
in the decade of the 1960's; during that time, indoor quiet
emerged as a competitive dimension.  Several manufacturers are
currently engaged in competitive advertising campaigns to sell
the quietness of their room air conditioners and are giving
their products brand or model names that imply the quietness.
Two large appliance manufacturers independently volunteered the
opinion that quiet is becoming more important to purchasers
every year.  One of these indicated that the fact that air
conditioning allows one to close the house against outside noise
may soon become a sales argument in air  conditioner
merchandising.  However, one leader in the current "quiet" race
indicated that their top-line model is not selling well.
     Most quieting effort for air conditioners  takes place in
modest engineering laboratories that are attached  to the  local
production facilities.  One  such laboratory reports spending
three man-years per year on  air conditioner noise  control; one
man-year per year was a more frequently  mentioned  level of
effort.  While the product policy people generally reported that
they were making maximal use of available quieting technology,
the study project acousticians who initiated  the  interviews felt
that current  state-of-the-art  technology was  not  being univer-
sally applied.
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     Two estimates we received indicate that quieting room air
conditioners adds 10 to 15$ to their price.  There may also be
an inherent trade-off between quietness and efficiency (since
one way to reduce air noise is to decrease air velocity).
Sometimes, quieting results in increasing the air conditioner's
physical dimensions, thus detracting from appearance as well as
from convenience and ease of installation.  There may also be
a trend toward model lines differentiated by noise output — i.e.,
an expensive quiet air conditioner and a cheaper noisier model.
One manager pointer out that there are anti-trust constraints
against organizing industry consensus on noise levels.

     Dishwashers and Food Disposers
     The mechanical differences between dishwashers and disposers
do not alter the fact that noise control pressures are similar
and that the manufacturers' approach to quieting is similar.
Thus our survey indicates that these two appliances logically
group together.
     Quiet is a saleable characteristic of dishwashers and
disposers, although the pressures for quieting are not so great
as for air conditioners.  While we are aware of no advertising
campaigns built exclusively on quiet, it is advertised with the
same prominence given to power and reliability.
     Noise levels from dishwashers and disposers are not currently
under public regulation, hence the incentive for quiet comes al-
most exclusively from the purchaser.  This gives rise to marked
differences between models; if one wishes, one can buy an
inexpensive, noisy dishwasher or disposer.  Reports from the
industry indicate that landlords frequently do just that.

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     Noise emissions from these two appliances are not  so
completely under the control of manufacturers as in the case  of
other appliances; the manner of installation greatly influences
structureborne and plumbing-borne noises.
     Dishwashers, however, present a promising example  of
industry's response to the purchaser's desire for lower noise
levels.   In a 1970 survey by the United States Steel Co., 48$
of dishwasher owners had no complaints about their appliance,
but of those who did, more complained about noise than  about
any other aspect of its operation.  Both survey data and mar-
keting "lore" indicate that the purchaser who has previously
used these appliances puts a higher value on quietness  than
does the new user.
     The costs of quieting were estimated by one dishwasher
manufacturer to be 10$ and by another to add $1 to $2 to manu-
facturing costs.  A disposer manufacturer felt that quieting
would add 12% to a product cost, whereas a retailer of disposers
estimated 18*.  Quieting these machines might deny their
availability to those least able to pay.
     In the case of dishwashers, one manufacturer indicated
the possibility of trade-offs between noise and maintenance
costs, and reliability.  Another indicated a trade-off between
water velocity and quiet but expressed the opinion that there
are no serious technical restraints to quieting dishwashers.
     In the case of disposers, industry claims inherent problems
with water and grinding noise  (especially with the noise of
grinding bones).  Some noise is considered necessary to the
user's safety, so he will know when the disposer  is operating
and when it has finished grinding.
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     So far, a number of sophisticated techniques have been
applied to dishwashers:  isolation, damping, and parts re-design.
Manufacturers of both dishwashers and disposers have tried to
improve the quality of installation by providing carefully drawn
instructions and flexible fittings.  One company has reduced
noise on its top-line dishwasher from 82 to ?6 dB(A) (at an
unspecified distance) since 1967 and plans a further reduction
in the next few years.  Another manufacturer expressed only the
desire to keep abreast of the competition; this company tests
each machine for noise, rejecting something under 1%.
     None of the manufacturers interviewed intends to give up
his noisier "economy" lines; goals did not seem to be appreciably
influenced by the prospects of noise regulation.
     The companies interviewed claimed to have adequate acoustic
test facilities, although the efforts devoted to testing and to
development varied widely in quantity and quality.

     Water Closets
     If evidence from mail order catalogues is reliable,
quietness in water closets is a marketable attribute.  Two top-
line, "low profile" models prominently feature quiet in their
advertising.  One manufacturer indicated in an interview that
placement of the height of the tank involves a trade-off between
quiet and efficiency, and indicated that quiet designs may be
less reliable, less efficient, and more expensive.  Like dish-
washers and food-waste disposers, economy-models are noisier
than more expensive ones.
     Currently, one company is trying to eliminate a water hiss
that occurs when the tank is full.
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     Other Major Appliances
     Quieter clothes washers, clothes dryers, and refrigerators
tend to be by-products of engineering originally undertaken with
other objectives in mind.  The classic case is a washing machine
model that was incidentally quieted when two gears were removed
from the power train to save cost.  In the context of product
improvement, noise is generally treated as a secondary design
goal, although manufacturers are concerned that engineering
changes may produce noisier products.  For example, refrigera-
tors are becoming larger and noisier as manufacturers seek to
meet the demand for special options such as ice makers; a
spinner-type washing machine produced higher noise levels when
spinner speed was increased to 2000 rpm.
     Two of four manufacturers interviewed make quiet models of
washing machines that sell at a $10 to $20 premium; sales for
both lines are disappointing.  None of the other models of
these companies is marketed  on the basis  of  quiet  nor  do  the
mail-order catalogues feature quiet.  The  single exception  is
a spinner-type washer in which "quiet operation" appears  in the
small-type description.  There is, then,   relatively little
evidence of pressure for quieting appliances  of this type.
     Yet, despite the weakness of market  pressures, considerable
quieting effort has gone into the design  of  these  appliances,
especially washing machines.  One manufacturer mentioned  six
different quieting projects  that  have recently been completed or
are underway.   A refrigerator manufacturer mentioned an effort
to avoid strange or unidentifiable noise.  No specific  efforts
to quiet dryers were uncovered.
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     Vacuum Cleaners
     The manufacturers of vacuum cleaners believe that the
market pressures are for noisy machines.  The three manufacturers
and one large retailer interviewed are all convinced that cus-
tomers use noise as the basis for judging a machine's power.
For example, after concentrated technical effort, a manufacturer
had significantly reduced the noise from a canister model with-
out reducing its cleaning capability.  Housewives who partici-
pated in a marketing trial wanted to know "if the machines were
really cleaning".
     Neither of the large "private label" retailers we consulted
mention quiet as a design goal.  In fact, in advertising a nap
adjuster, one company writes "... just slide the bar across
until you hear the right cleaning purr".  One company that
carefully analyzes its correspondence from customers finds
virtually no noise complaints about vacuum cleaners or any of
its other portable appliances.
     A reasonable level of engineering effort has produced
feasible solutions to vacuum cleaner noise problems; according
to all interviewed, however, these solutions are not being
applied to products that are sold, because vacuum cleaner manu-
facturers and retailers do not sense a demand for quieter
products.  In fact, the sale of upright cleaners, whose beaters
make them noisier, is growing at the expense of the sale of
canister models.  Apparently, the beater action of upright
cleaners can better handle the new deep-pile weaves that make
modern carpets harder to clean.  There are technological limits
to the quieting of upright vacuum cleaners, because of the inter-
action between the beater and the carpet, but the noise levels
of production models seems to be determined by customer usage
demand rather than by technological limitations.
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     The company that developed the quiet canister cleaner
employs a physicist who works full-time on noise-control studies.
The company calls in noise consultants about four times a year
and samples its customers at six-month and two-year intervals.
They have given considerable attention to the problem of beater
noise and estimate that solutions that would not reduce a
machine's efficiency would add 50$ to its price.
     Another large company made a study ten years ago (at a cost
of about $30,000) in which they developed ways of reducing
vacuum cleaner noise in middle and high frequencies by about
XO dB(A).  They have just contracted for a study of their com-
petitors' canister machines and of the effect of using alternate
motors in their own machines.  Although they have available
technical staff and laboratory facilities in-house, they have
never applied the results of their studies to the products they
'market because of customer attitude toward noise.

     Small Appliances
     During the interviews incidental  information was gathered
from five different companies concerning eleven  small appliances:
blenders, can openers,  coffee mills, electric knives, fans, hair
dryers,  ice crushers, knife  sharpeners, mixers,  oral lavages,
and electric tooth brushes.  Manufacturers  feel  that there is
public pressure for these appliances to  sound as  though  they
are "really doing their jobs".   One manufacturer  offered the
generalization that, in the  small  appliance  field,  the  quality
of the sound is more important than the  quantity.   An  appliance
must sound  "right".  Some must sound powerful,  some reliable,
and none as though they are  malfunctioning  or undergoing
excessive wear.   This manufacturer expressed the belief that  an
accurate interpretation of  the customers'  desires in  these  areas
-j_s a condition  for remaining in  business.
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      This market pressure leads to diverse noise-control
 objectives, both among companies and between product  lines
 produced by a single company.   Customer complaints  were
 reported about the noise from fans and hair dryers,  and one
 marketing executive was quoted as believing that  quiet  is a
 saleable aspect of mixers.   One company which does  not  manufac-
 ture  the ice crusher that is sold under its label put a fairly
 high  value on quietness in  selecting the model it sells.  Yet,
 none  of  these small appliances was described as quiet in
 either of the two  mail-order catalogues that we examined.
 Blenders and electric  can openers were  specifically described by
 the managers inverviewed as  being appropriately noisy.   A company
 which we did not interview was cited as having quieted  a blender;
 in so doing,  they  slowed it  down so  that it became  less effi-
 cient.   At  least one  laboratory is seeking entirely new ways of
 comminuting  foods  that  could be both quieter and  cheaper than
 blenders.  Another  is designing a screw-type  crushing tool that
 will substitute a  growling sound for the raucous  sound  of the
 chipper  that  current ice  crushers  employ.
     There is  also  a search  for fan  blade  configurations that
 will eliminate  certain  predominant frequencies  and produce a
 more pleasing  sound.  In  addition  to  room  fans, this experimen-
 tation includes hair dryers, where quieter  designs for  air
 passages are also being  sought.
     Rubber feet have been added  to  electric  coffee mills to
reduce vibration noise, but shielding is not being used because
of its adverse effects on costs,  size,  and  aesthetic design.
Plastic beaters for mixers promise to reduce both noise and
costs.
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     Many of these appliances are powered by universal-type
motors, which are inexpensive, powerful for their size,  but
noisy.  The size-power ratio considered important in such appli-
ances as hand mixers, electric knives, can openers, and  motor-
in-the-bonnet hair dryers.  Conventional hair dryers also embody
a trade-off between speed and quiet; one hair dryer model that
was marketed as "quiet" took 30 to 75 minutes longer to  dry
hair than faster, noisier models.
     Speed or the potential power that speed permits was cited
as important to electric knives, can openers, and blenders.   In
the case of blenders, one engineer argued that, if they  were
slowed down, the intensity of the noise would simply be  traded
for noise duration with no lessening of resulting impact.
There is also reported to be a trade-off  for electric tooth
brushes between noise and cleansing effectiveness.
      Cases of limitations on quieting were  pointed out  for knife
sharpeners where there is grinder-blade  interaction, as well as
for blenders where rotating  knives  are  essential and a  glass
casing is necessary  if the housewife  is  to  monitor the  process
visually.  In the case of blenders, there is hesitation to
experiment with  consumer  preferences  since  the  already  intense
domestic competition is being raised  by the entrance of
Japanese products into the market.
      Small appliance manufacturers  make frequent use of
subjective noise  judgements  in  their  developmental work.  Their
product  laboratories tend to be  less  sophisticated than those
for major  appliances, although  many have access to central
acoustical  laboratories  of  great sophistication.   One small
appliance  manufacturer tests new products in his employees'
homes.   If employees object  to  the  noise the new model  makes
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they are asked if they would be willing to pay for a quieter
product.  The general result of this approach is to make this
manufacturer pessimistic about the economic pay-off from
quieter products.
     Although specific noise goals are hard to identify in the
appliance industry and although some manufacturers seem dis-
couraged with the return on their efforts to date, all those
interviewed plan to persist in quieting efforts.  Technological
limits have not yet been reached.  One manufacturer believes
that the earlier competition-which emphasised compactness has
now been replaced with an emphasis on quiet.  Accordingly,
industry generally plans to hold the size of future models
constant and to concentrate on producing quieter models, while
presumably keeping prices within competitive limits.
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5.  CONCLUSIONS AND RECOMMENDATIONS
     This report has presented a broad range of facets  concerning
the noise characteristics of construction,  appliances,  and  bui] cl-
ing equipment, the influence of this noise  on our lives,  and  the
nature of the industries producing and using this machinery.   In
this section, we summarize our findings and recommend what  we
believe to be a balanced noise abatement program that may be
pursued by EPA.

5 . i  Conclusions
     One of the most striking factors to emerge from this study
j_s the monumental complexity of the physical, social, and indus-
trial system that 'we have attempted to understand.-  There is  a
v/ide spectrum of noise-producing machinery types utilized for
many different purposes in a nearly endless number of situations.
This heterogeneity makes a characterization of even the  average
properties of the sources and transmission paths difficult at
kest.  Of course, nobody is exposed to average conditions but
Bather to some part of a multi-variable distribution of  circum-
stances, making some notion of  the  range of source/path/receivec
situation desirable.  Furthermore,  human response to noise varies
widely among  individuals and depends  not only  on the readily mea-
surable  aspects of  sound such as level and  spectrum, but also on
  ch factors  as attitudes, predispositions,  the  information  con-
tent of  the  sound,  and  concurrent  nonauditory  stimuli.   The  in-
dustrial situation  is equally  complex,  the  judgement  of  industrial
leaders  and  their  concommitant  directives  being  influenced by
  arketplace  and  legislative demands,  as well  as  by  their own
  ersonal attitudes.   In presenting what we  feel  are the  salient
features of  this  complex  system,  we claim  to have  observed no
  ore  than the top  of  the  iceberg — and even that at some distance.
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 5.1.1   Sources
     Despite  the  tremendous range of equipment, the noise-producing
 mechanisms are often similar and may be identified as part of a
 much smaller  class.  The principal source of noise in many types
 of  construction equipment, for example, is the diesel engine.
 Exhaust noise is  most readily identifiable with structural sound
 radiation and inlet noise is also of importance.  Additionally,
 the hydraulics, fans, and transmissions of construction equipment
 generate loud and identifiable noise levels.  Such heavy equip-
 ment often creates levels in excess of 90 dB(A) at 50 ft.  Dril-
 ling and cutting  machinery are also extremely noisy as are impact
 tools such as riveters, pavement breakers, certain powered
 wrenches, and most pile drivers.  Noise from jack hammers and rock
 drills often lies between 80 and 100 dB(A) at 50 ft; pile driver
 noise can exceed  100 dB(A).  Almost invariably, construction
 equipment, regardless of its size, is noisy.
     In evaluating the control technology of construction noise,
 one finds that approximately 10 dB(A) of noiae reduction are
 generally achievable using state-of-the-art techniques; 20 dB(A)
 could no doubt be achieved with a certain level of technology
 development.   Of course, these are average values. 'For some
 equipment, such as that sold without exhaust mufflers, greater
noise reduction would probably be easily achieved; for others,
 such as riveters,  considerable effort would be required to meet
these objectives.
     The noise levels of home appliances span a much broader
range than those of construction equipment.  Certain appliances
such as food freezers or refrigerators are rather quiet at 30 to
40 dB(A), measured at 3 ft; other items such as food blenders
can be as noisy as 80 to 90 dB(A) depending on the type, speed,

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and food being processed.  Garbage disposers may even exceed
90 dB(A).  By and large, the noisiest classes of home equipment
are powered garden and shop tools.  Noise from electric lawn
mowers, hedge trimmers, and grass edgers all measured between
80 and 90 dB(A).  Some shop tools generated nearly 100 dB(A).
     Noise from appliances is attributable to electric motors and
cooling fans, plus the components being driven by the motors.
For refrigeration equipment, these components are compressors
and blowers; for food-waste disposers, they are grinders; for
shop tools they are typically cutting or grinding elements, often
connected to the motor by roise-producing gears.  As with con-
struction equipment, noise reduction levels of 10 dB(A) are gen-
erally achievable with state-of-the-art techniques; 20 dB(A)
often requires either extensive application .of existing techniques
Ov the development of new technology to obtain the same results at
less cost.
     Building equipment probably has as large a range of noise-
jnaking devices and noise levels as construction and appliances
combined.  Diesel engines, gas turbines, and large electric gen-
erators or motors are all utilized, especially in so-called
•'total energy systems" which supply both electric power and tem-
perature control' for buildings.  Refrigeration and heating equip-
jnent, blowers, diffusers, and fluorescent light transformers all
generate noise.  Fortunately, the noisiest sources of building
equipment are usually remotely located, typically in mechanical
equipment rooms.  Isolating people from this noise is mainly done
through architectural treatment.
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 5.1.2  Impact
      We have tried to measure the Impact  of noise  on people  in
 terms of the levels to which they are  exposed,  the duration,  and
 the number of people.   In a one  year period approximately  30
 million Americans  will find themselves  living  or working near a
 construction site.   The noise from this site will  be sufficiently
 high io interfere  with their conversation  most  of  the day.  Three
 million workers  with night  shifts  and  2.5  million  children under
 four who may require naps  live near  these  sites.   Many will either
 find it more difficult to  fall asleep  or be  awakened during their
 sleep  because  of construction noise.   On the average,  a metropolitan-
 area resident  or worker  passes a  construction  site  every other day.
 Pedestrians  can  be  exposed  to noise  levels  in  excess  of 90 dB(A).
 Automobile drivers  and passengers  will often close  their windows,
 thereby  reducing the exposure to  approximately  80  dB(A).  Although
 many  operators of heavy  construction equipment  are  losing their
 hearing  because  of  noise [25], hearing damage to persons in the
 environs  of  construction sites does not appear  to  be  a substantial
 problem.  Most people  residing or  working  in buildings neighboring
 construction sites  are exposed to  less than  70  dB(A)  most of  the
 time.   Some  pedestrians are  exposed to levels that  could contrib-
 ute  to hearing loss particularly if these people are  exposed  to
 high noise levels during other times of the  day.
     One of the most significant aspects of  construction noise is
 that, in any year,  15% of the population are exposed  roughly  eight
 hours a day, five days a week for many  weeks or months.  They have
 no control over the noise nor do they have much respite from  it.
The argument that construction is  temporary  has little appeal to
people living near a several year project  or one series of projects
 after another located all around them - after all,  they argue,
 life itself is temporary.
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     Appliances have an impact on people in a rather different
      Most appliances affect only the people using them and only
'for a relatively brief time while they are in operation.  For
example, a food blender may generate 80 dB(A), but only for
30 seconds, at the end of which the user has a desired product.
This leads to quite different attitudes toward appliances vis
a vis construction equipment as bothersome noise sources.  Of
course, not all appliances affect only the user and his family.
Appliances which affect neighbors are typically those which are
t>uilt in to the home structure or plumbing and those which are
used outside.  Thus, food-waste disposers, dishwashers, water
valves, and toilets are found to annoy and sometimes interfere
with the sleep of people in multifamily dwellings.  Powered
garden tools such as lawn mowers, hedge clippers, and edge trim-
mers as well as power tools used outdoors  (e.g., circular saws,
drills, sanders) also generate sufficiently high noise  levels
to awaken or annoy neighbors.
     One of the most striking aspect of appliances  is their num-
ber.  Roughly one billion appliances now are used in homes through-
oUt the U.S.  Virtually everyone owns at least  some; e.g., 99«W
of homes are equipped with a refrigerator, over 90% have vacuum
cleaners. By and large, people in the upper socio-economic stratum
ftave more appliances.  However, the  generally increasing affluence
of the nation coupled with the relatively  constant  price of appli-
ances over the past 15 years  (despite the  inflationary  growth of
 ost other consumer items) has stimulated  the profusion of appli-
ances into homes at every economic  level.  This large, number of
appliances and their year-round use  (with  certain obvious  excep-
tions) has made the exposure  to appliance  noise very  large indeed.
in fa-ct» appliances account  for more person-hours of  speech  inter-
ference, sleep interruption,  and hearing  damage than  construction.
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However, the impact In terras of annoyance is probably not so
great, owing in large part to the controllability of many appli-
ance operation times.  For example, one does not have to run the
dishwasher while listening to T.V., but it is difficult to ask
the pile driver operator outside to cease work until a program
of interest is over.

5.1.3  Industry program*-
     Industry activities in product quieting can best be under-
stood by first considering the pressures they perceive.  Demand
for quiet appliances reaches manufacturers directly from the
purchasers in the marketplace.   The people who are exposed to
noise, for the most part, are also those who purchase the appli-
ance, or at least influence its selection.  Demand for quiet
construction equipment is also made by people living or working
near construction sites.  They generally have no economic in-
fluence on the building contractor or equipment manufacturer.
Hence, their demands have largely gone unheeded and have been
redirected through legislative bodies.  A few successes in this
arena have begun to create a marketplace demand for quiet equip-
ment by contractors who "see the handwriting on the wall" and
are willing to pay something of a premium for equipment that will
not be illegal to operate in a few years when anticipated wider-
ranging legislative controls are enacted.
     The response to pressure for quiet has varied within and
across the appliance and construction industries.  Some appliance
manufacturers have made a credible effort to develop capabilities
to deal with noise-control problems and to design appropriate
noise-control measures into their products.  This has been espe-
cially true in the major appliance industry where air conditioners
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 and,  more  recently,  dish-washers and food-waste disposers are
 being treated.   As  one might expect, the objective of disposer
 treatment  is  to  reduce noise within the kitchen containing the
 unit.   We  know of no disposer designed to reduce transmission
 of  noise through plumbing and into adjacent apartments.  The
 disposers  that incorporate airborne sound suppression are top-
 of-the-line items designed for use by the purchaser.  Bottom-
 of-the-line disposers often have no noise treatment whatsoever
 and are usually  installed in multifamily dwellings.  Generally
 speaking,  when noise control is introduced in appliances, it is
 in  top-of-the-line  items.  There, it serves partly as an added
 luxury and partly as a test of market acceptability.  If success-
 ful,  it will  often  be introduced in other line items; if unsuccess-
 ful (for whatever reason) the notion will often develop and per-
 sist  that  consumers  simply do not care about noise.
      The construction equipment industry also shows a spectrum
 of  levels  of  response to pressure for product quieting.  A very
 few companies have  foreseen the demand for quiet equipment and
 have  begun a  line of products that are significantly quieter than
 competitive models.   Some companies have conducted experimental
 noise control projects, often with only a modicum of success.
 Several companies appear to have given noise-control very little
 effort (e.g., some heavy construction equipment does not even use
 exhaust mufflers for diesel engines).  On the whole, noise has
 only begun to become a serious factor in the construction indus-
try, which lacks much of the expertise required to deal success-
fully with it.
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5.2  Recommendations
     Most of the work presented in this report is of the nature
of background material that must be applied to the problem of
noise reduction to be of real value.  Our recommendations there-
fore relate to the application of this information and the steps
that we feel ought to proceed from it.
     There appear to be two primary means by which the EPA can
influence industry to bring about noise control.   The first is
to regulate the maximum allowable noise levels that can be pro-
duced by new equipment.  The second is by instituting a mechanism
for disseminating information to the consumer:  namely, requiring
the labeling of noisy products.  In situations where the party
exposed to noise is not the purchaser of the noisy equipment and
is not in a position to influence the noise level or operation
of the equipment, it appears that noise standards must be gen-
erated and applied to bring about noise reduction.  This is
largely the case in the construction industry, where the princi-
pal recourse to construction noise control by the community has
been through local legislation.  On the other hand, when the
purchaser is, for all practical purposes, the only party affected
by a noisy source and that source is not likely to contribute
seriously to hearing damage, then standards appear to constrain
unnecessarily one's freedom of choice.  Rather it would seem
appropriate to ensure that the purchaser is informed of the
levels to which he will be exposed, but that he be allowed the
freedom to weigh noise against other factors  (e.g., price, size,
durability) in reaching a decision among alternative products.
     Setting standards and labeling requirements  is no mean task.
There are technical issues that must be resolved involving the
conditions under which noise is to be measured.  For example,
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the type of sink in which a garbage disposer is installed and
the character of food waste being disposed of, must be carefully
specified to obtain meaningful and uniform results.  Somewhat
more difficult is the task of determining the maximum allowable
levels for different kinds of equipment.  In a sense, these levels
invariably represent a compromise between desired values and
values that are economically acceptable.  This concept may be
illustrated qualitatively by Pig. 27 in which we plot cost vs
noise reduction.  Cost is used to include capital, operation,
and maintenance expenditures owing to the application of noise
control treatment and whatever performance degradation might
occur because of such treatment.  Automobile mufflers are a good
example; they increase the price of an automobile, often require
replacement during the life of an automobile, and  slightly de-
grade engine performance.  Results achievable by application of
state-of-the-art noise-control techniques are represented by an
exponentially increasing curve.  The first few dB  of noise reduc-
tion are typically achieved at low cost; costs gain  substantially
as greater levels of quieting are sought.  Also shown in the
Fig- 27 is a cost vs noise reduction curve that might be achiev-
able subsequent to noise-control research and development.   In
fact, it can probably be said that the  sole objective of R&D
should be to lower the state-of-the-art  curve.  The  third  curve
in Fig* 27 shows a relation between cost and noise reduction
Deemed acceptable by the decision-makers.  The curve is  concave
downward illustrating the  notion that as a machine is made quieter,
each increment  of noise reduction is worth less and  less.  The
intersection of the  state-of-the-art curve with the  acceptable
cost vs noise reduction curve determines the noise reduction one
  s willing to specify.  If this  level of reduction is inadequate,
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                        NOISE REDUCTION
FIG.  27.   COST OF NOISE CONTROL VS  NOISE  REDUCTION
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it is necessary to conduct R&D to achieve a lower state-of-the-
art curve and increase the level of noise reduction that  can" be
justified economically.
     Each party has its own view of the level of the acceptable
cost vs noise reduction curve.  For equipment manufacturers who
find little marketplace demand for quiet products, the curve is
low.  People living or working near noisy equipment would
naturally draw the curve at a higher level, especially if they
did not have to bear a significant part of the cost for quieting
the machinery.  One of the problems that EPA will have to face
is to develop an acceptability curve that is, in some sense,
fair to all parties.  Although it is difficult, if not impossible,
to develop such curves quantitatively, it will be necessary for
a decision maker to be aware of the pertinent relations between
cost and noise reduction and to account for them in selecting
the levels to be achieved.  To assist in this process, we rec-
ommend here studies of the technology and economics of noise
abatement, the economic impact of noise control, the type of
improved noise criteria that ought to be developed, and social-
indicator studies to measure the attitudes of the public to
noise and noise control.  First, let us consider which equipment
ought to be regulated by standards and which by  labeling.

5.2.1  Standards and labeling
     We recommend that noise  sources having  a significant impact
on parties who derive  little  direct benefit  from the source  ought
to be controlled by the establishment of maximum allowable noise
Bevels.  This would include most construction equipment, con-
struction sites, and certain  types of appliances.   Among the
items of construction  equipment  requiring  standards are  all  ma-
chinery powered by  internal combustion  engines  as well as  tools
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utilizing impact or cutting mechanisms, such as drills, pavement
breakers, and saws.  Construction site noise levels ought to be
regulated to ensure that the contractor deploy and utilize his
machinery in a way that minimizes community noise exposure.
Typical appliances requiring regulation are electric garden tools
(e.g., lawn mowers, hedge clippers, edge trimmers), food-waste
disposers, dishwashers, air conditioners, and shop tools.  Because
the noise of hazardous tools also serves to inform the user of
their operation, minimum as well as maximum levels out to be set.
     For standards to be applied in a way that may reasonably be
met by industry and yet are sufficient to have an impact, we
recommend the establishment of a three-phase program.  A decreasing
sequence of levels would be established and would go into effect
approximately, one, four, and seven years subsequent to the time
at which the levels are publicly announced.

     One year
     The purpose of the first phase is to ensure that highly
effective off-the-shelf noise control equipment is utilized on
all new machinery.  Thus, all.machinery powered by internal com-
bustion engines would be required to be equipped with high-quality
mufflers, for example.  (This contrasts with the current situation
in which some construction equipment is advertised and sold with-
out any muffling whatsoever.)  One year appears adequate for manu-
facturers to order, receive, and install such equipment.

     Four leavs
     The second phase would become effective approximately four
years after announcement of levels.  These levels would be selected
to ensure that state-of-the-art noise control techniques are

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incorporated in equipment.  To achieve these levels,  the manu-
facturer might have to use sound-absorptive engine enclosures,
for example.  Appliances might have to incorporate vibration
isolators for all motors and pumps.  Since the type of treatment
envisioned here requires minor changes to equipment,  four years
appears adequate for manufacturers to design noise treatment
and retool selected items of their production lines.

     Seven Years
     The levels to become effective after a period of seven years
should largely represent state-of-the-art advances and should
have a significant impact on the level generated by the noise
source.  Twenty dB(A) of noise reduction for the most offensive
construction equipment and appliances would seem reasonable.
Seven years allows sufficient time for the research and develop-
ment needed for state-of-the-art advances and the incorporation
Of the fruits of this work in production items.

     We also recommend labeling of appliances generating signifi-
cant noise levels affecting primarily the user.  Included in  a
-List of items to be labeled are all items controlled by standards,
as well as shop tools, vacuum cleaners, food blenders, fans,  and
hair dryers.  Our rationale for labeling rather than standard
getting is that a person should be informed of the noise to which
he will expose himself and then be free to consider noise as  but
one of a number of factors accounting for his selection of  a
particular brand.  Noise-control standards would no doubt raise
appliance prices, unnecessarily restricting the consumer's  range
of choice.
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5.2.2  Technology evaluation, demonstration, and development
     We recommend the expenditure of appropriate levels of effort
to evaluate, demonstrate, and develop technology in support of
the establishment of standards.  These studies are as follows:

     Labeling
     To make labeling meaningful, a consistent set of test pro-
cedures should be developed for each type of appliance or item
of building equipment.  This is especially important for appli-
ances whose noise characteristics depend heavily on the instal-
lation.  Prominent among these are food-waste disposers, dish-
washers,  plumbing fixtures, and vacuum cleaners (which may rest
on a rug or a hard floor).

     Standards — Phase I
     The first recommended phase of standard setting establishes
noise levels that can be met if highly effective off-the-shelf
noise control devices are used on all equipment.  Prior to the
establishment of such standards, a program to measure the noise
generated by selected machinery samples targeted for incorporation
of such devices would seem appropriate.

     Standards — Phase II
     The second phase of standards would specify levels requiring
the application of noise-control treatment.  We recommend that
EPA conduct noise-control demonstration projects on selected items
for three reasons.  First,  achievable levels of noise reduction
can be accurately evaluated, and accordingly specified, only-by
means of such programs.   Without actually implementing noise-
reduction techniques there would probably be an unacceptable
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level of uncertainty associated with predictions.  Furthermore,
practical implementation problems are often not uncovered until
treatment is actually put into practice.  Second, such demonstra-
tion of results achievable by-means of'state-of-the-art noise
treatment would put to rest any objections raised by the affected
industry concerning the technological feasibility of achieving
specified levels.  Finally, the technical information generated
ky a demonstration program would be valuable across the affected
industry, especially to small companies who often lack the req-
uisite technical capability in noise control.

     Standards — Phase III
     The third recommended phase of standards is designed to
nave a significant impact on noise levels and will probably be
achievable only through state-of-the-art advances in noise-control
technology.  To ensure that the state-of-the-art is appropriately
advanced in sufficient time for implementation in new machinery
we recommend the immediate commencement of R&D programs dealing
vtfith the following important aspects of construction and  appli-
ance noise  (in approximate order of priority):

    • diesel engines
    • mufflers
    • hydraulic systems
    • cooling systems
    • impact and  cutting  tools
    • other  power plants:
         gas turbines  (for nonaitfcraft use)
         electric motors
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    • transmissions (gears)
    • water valves
                            i
5.3  Economic Impact Studies
     Determining the optimum balance between public's desire for
quiet and the distributed costs required to achieve it by means
of rigorous systems analysis effort would require a large-scale
simulation of the economics of the construction industry and its
place in the U.S. economy.  Such a study is not feasible if usable
results are required in a short time or if expenditure of funds
is limited.  It is possible, however, to make some choices as to
what to quiet and how to quiet it, by doing some fairly unsophis-
ticated investigation of how the quieting costs get distributed
through the industry and the economy.  We recommend treatment of:

   • The impact of noise on various segments of the population.
     (This has largely been performed under the existing EPA
     contract and needs but a little expansion.)
   • Estimated costs of quieting selected pieces of equipment as
     a function of degree of quieting.  (This would be an order-
     of-magnitude estimate.  Data can be obtained from price
     information on existing mufflers, heavy casings, absorptive
     materials,  etc., as well as a study of price differentials
     between existing quieted and unquieted machinery — not just
     construction equipment.  Costs of nonhardware guiding tech-
     niques, such as scheduling site operations to avoid using
     many prices of equipment at once, would be estimated by
     constructing typical scenarios and consulting with industry
     representatives to determine increases in construction cost
     increases (or decreases).  Allowance should be made for uses
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     in which a change in equipment design or operation  results
     in greater productivity,  reliability, etc.   The  effect  of
     such an occurrence could  be a net negative  quieting cost.)
   •  The distribution of increased equipment  cost among  producers,
     purchasers and the purchaser's customers.   (Part of the cost
     will be absorbed by each, depending on the  demand elasticity
     of the commodity.  This information exists  in published
     studies of the economics  of the construction industry.)
   •  Allocation of increased equipment costs/rentals  among various
     types of construction.  (The resulting increase  in construc-
     tion costs are a strong function of what is being built.
     Equipment rental typically makes up 2Q% of  the cost of civil
     works constructions, 10%  of the cost of highways, but only
     2% in the case of buildings.)

     The above data would be used to compute the economic effect
of quieting equipment on the public.  The outputs would be:

   •  The expected increase in costs and rentals  of housing,
     offices, industrial space, etc., as a function of the
     degree and method of site quieting.  Also of interest  is
     the degree of intersection of the sets of:    (1)  surrounding
     inhabitants, who get the benefits of quiet sites, and  (2)
     building users, who pay the cost, or part of it.
   •  Expected increase in state, municipal, and federal taxes as
     a result of increased cost of public works construction, etc.

     The net result of the study would be recommendations for an
orderly construction quieting program based on the information
Developed above.  The  criteria by which specific  techniques or
regulations would be judged are:
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    •  Cost-effectiveness  (the degree of quieting achieved per
      dollar  expended).
    •  Cost-benefits  (the  reduction in community noise exposure as
      a function  of  quieting cost).
    •  Equitability (the degree to which the beneficiaries of a
      quieting program bear the expense of that program).

5.4   A Program of Public Support Development
      Our contact with managers of construction equipment and home
appliance manufacturing  companies has convinced us that their
perspective  on and  attitudes toward noise control programs will
strongly influence  the efforts they make to quiet their products.
This  is even more true of the values they hold regarding the
legitimacy and worth of quiet environments.  Indeed, we regard
the public support  of noise abatement efforts as a crucial vari-
able  in the  success of these efforts.
      We would, therefore, recommend a continuous program to
diagnose and develop public support for noise abatement.  Such
a program would embrace five activities:

      Exploration of Programs in Other Areas
      We visualize this as an inquiry both into the theory of
public opinion, attitude change, and shifts in basic values and
into  the actual techniques of public support development that
have  been employed in other contexts.

     A Continuous Inventory of Opinion-Leader Attitudes
     This would be a program of interviews with opinion leaders
who are dealing with noise abatement.  It would include leaders
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in government, business, relevant professions,  and consumer-  and
ecology-advocate groups.

     A Continuous Inventory of Public Awareness,  Attitudes, and
     Values
     These should be measured on a well-designed material sample
on a continuous basis so that trends over time  could be assessed
concerning public knowledge, attitudes, and values.

     Program Development
     A program, based on information obtained from the three  ac-
tivities above, should be developed (1) to optimize the kind  and
degree of regulation which can be supported by  the public opinion
that exists, (2) to prescribe a public information program that
will improve the. quality of public opinion, and (3) to identify
profitable areas for demonstration programs.

     The Development and Administration of Pilot Programs of
     Noise Abatement
     These pilot programs should test the relation of regulation
to various levels of public support in the same sense that pilot
programs that test innovative technological prototypes are de-
veloped.
     We should like to say a word'regarding the usefulness and
feasibility of the continuous inventories of leader opinion and
public opinion — activities 2 and 3 above.
     Field research in the behavioral sciences has now reached
the point that useful social indicators can often be developed
if their development is undertaken on a pragmatic basis.  We do
                               181

-------
 not visualize that these survey activities will be conducted at
 the level of public-opinion polls.  Again, the behavioral sciences
 have matured to the point that much more useful kinds of informa-
 tion can be gathered.  We know from previous noise surveys that
 socio-economic status and attitudes toward noise makers influence
 noise annoyance and noise complaints.   A recent study of motor
 vehicle noise that we have conducted indicates that the necessity
 of the noise, and the degree to which  one perceives the noise as
 an intrusion, influences the level of  annoyance.   The survey
 efforts proposed would tap  values  that would assist in the formu-
 lation of noise  criteria.   Are people  willing to  put  up with
 "bearable"  levels  of  noise  or  do they  now demand  reduction to
 "comfortable" levels?  Of  greatest importance may  be  attitudes
 toward the  regulating process  itself.   By now it  is well-
 established  in social psychology that  basic  orientations towards
 the  sources  of influence alter behavior.   With regard to the
 product  manufacturer  who promises  to become  an object of regu-
 lation,  theory would  predict that  one's  enforcement problems
 would  be  quite different if  the  manufacturers  complied to  regu-
 lation  because of  fear, because  compliance was  expected by  his
 reference groups,  or  because his own values  induced compliance.
 These psychological orientations can be measured through inter-
views .
5.5  Social Impact
     The following recommendations are made to evaluate the im-
pact of noise not only from the sources undertconsideration in
the current report but also from other sources.
     1.  The most fundamental action that can be taken to further
the assessment of noise impact is to initiate research leading
                              182

-------
to development of an absolute scale of annoyance for all noise
exposure.  The first stage of such a research program would
obviously be a planning effort to structure the task and prepare
detailed plans for its execution.
     The need for such research is immediate.  Existing methods
for estimating annoyance are relative rather than absolute, limited
in scope and application, not widely accepted, and of dubious
utility.  The intended research would entail simultaneous measure-
ment of both complaint behavior and the offending acoustic signals
producing complaints, at the tirr& of annoyance.  A continuous sur-
vey of residential noise annoyance over a considerable period of
time is needed, as are surveys of noise annoyance in other environ-
ments.  Until a well-founded research program of this sort is
undertaken, one must continue to rely upon personal experience
or the distortions of the popular press for estimates of the true
magnitude of the annoyance problem.
     2.  Since speech interference proved to be such a widespread
consequence of exposure to the noise sources considered in this
report, research should be conducted to determine how accurately
speech interference predictions made on the basis of laboratory
data may 'be extended to real-life situations.  Almost all  current
Knowledge of speech interference effects has been produced by
studies employing steady-state noise as the interfering signal.
No research has been conducted on potentially  crucial effects of
temporal parameters of noise distributions  (including frequency,
duration, and periodicity of interference)  on  verbal communication.
Further, little if anything is known of the annoyance value  of
speech interference.  Trade-offs governing  the relative annoyance
of:frequent but short interruptions vs infrequent but long inter-
ruptions of verbal communication have not been investigated.
jt therefore remains impossible to predict  whether people  would
                              183

-------
suffer more speech interference from one type of appliance than
another; whether redesign of machinery for longer duration but
lower level noise output would be helpful; whether scheduling
changes in the operation of construction machinery would reduce
speech interference; and so forth.
     3.  Noise education programs should be designed to provide
                                    «
the public with the information needed to make decisions about
the desirability of noise exposure.  A noise-conscious public
can exercise a modicum of control over its noise exposure through
its purchasing power and its demand's for noise control legisla-
tion.  Consideration should be given 'to preparation of public
information pamphlets, recordings, or other means of increasing
public awareness of noise exposure.

-------
REFERENCES


1.   Schultz, T.J., "Community Noise Ratings: A Review," Supple-
     ment No. 1, Applied Acoustics, 1971.

2.   Robinson, D.W., "The Concept of Noise Pollution Level,"
     National Physics Laboratory Aero Report AC 38, March 1969.

3.   Schultz, T.J., "Technical Background for Noise Abatement in
     HUD's Operating Programs," BBN Report No. 2005, September
     1970.

Jj.   Beranek, L.L., Noise and Vibration Control, McGraw-Hill Book
     Company, New York (1971).

5.   "The Auditory Environment in the Home," a report by the
     Environmental Design Department, University of Wisconsin for
     Koss Electronics, Inc., Milwaukee, Wisconsin.

6.   Mikeska, E.E., "Noise in the Modern Home," Noise Control,
     May 1958, p. 40.

7.   BBN data measured in 1971.

8.   Mikeska, E.E., "Noise Levels in Homes," Noise Control,  May
     1957, PP. 11-14.

9.   "Field  Study of Residential Acoustics:  Acoustical  Performance
     of Apartments and Occupants' Responses," NAHB Research Founda-
     tion, Inc., Rockville, Maryland, 1967.

]_0.  Beranek, L.L., Noise Reduction, McGraw-Hill Book Company,
     New York (I960).

2.1.  "Noise  Study of a Domestic  Dishwasher,"  BBN  Rept.  No.  979,
     March 1963-

!2.  "Water  Closet Noise Studies,"  BBN  Rept.  No. 1402,  Dec.  1968.

-L3.  Cohen et al, Sociocusis-Hearing Loss  from  Non-Occupational
     Noise Exposure," Sound and  Vibration,  November  1970,  pp.  12-20,

14.  Kryter,  K., "Hazardous Exposure to Intermittent and Steady-
     State Noise," Report of  Working Group  46 NAS-NSC Committee
     on Hearing  and Bioacoustics,  January  1965.
                               185

-------
REFERENCES (Continued)


15.  Kryter,  K.,  The Effects of Noise on Man (Academic Press, N.Y.,
     1970).

16.  Miller,  J.,  personal communication, 1971-

17.  Webster, J.C., "SIL - Past, Present and Future," Sound and
     Vibration 3 (8):22-26, August 1969.

18.  Beranek, L.L., "Criteria for Office Quieting Based on
     Questionnaire Rating Studies," J.  Acoust.  Soc.  Amer., 28,
     Sept. 1956,  pp. 833-852.

19.  "Urban Traffic Noise: Status of Research and Legislation in
     Different Countries," Draft Report  of the  Consultative Group
     on Transportation Research, DAS/CSI/68.47  Revised; Organisa-
     tion for Economic Cooperation and Development,  Paris, Prance,
     4 March  1969.

20.  Lang, J., and Jansen, G., "Report on the Environmental
     Health Aspects of Noise Research and Noise Control," United
     Nations, World Health Organization, May 1967.

21.  Schieber, J.P., "Problemes Acoustiques du  Confort de Nuit",
     (Acoustical  Problems Concerning Nighttime  Comfort), Cahiers
     du Centre Scientifique et Technique du Batiment, No. 100;
     Cahier 869,  June 1969, Paris; p. 36.

22.  Metz, B., "Etude Analytique en Laboratoire de 1'Influence du
     Bruit sur le Sommeil," (Analytical  Laboratory Study of the
     Influence of Noise on Sleep), No.  63 PR 138, University of
     Strasbourg,  1968.

23.  Schieber, J.P., ."Contributions des  Etudes  de la Physiologie
     au Probleme  de la Determination des Zones  de Confort Acous-
     tique au Cours de Sommeil," (Contributions of Physiological
     Studies  to  the Problem of Determining Areas of Acoustic Com-
     fort during  Sleep), presented at a  Colloquium on the Defini-
     tion of  Human Requirements with Regard to  Noise, 18 & 19
     November 1968, Paris; published in  Revue d'Acoustique 3(10):
     104-112  (1970).

24.  Hildebrand,  J., "Noise Pollution: An Introduction to the
     Problem and  an Outline for Future Legal Research," Columbia
     Law Review  70, April 1970.
                              186

-------
REFERENCES (Continued)


25.  Kryter, K., "Laboratory Tests of Physiological-Psychological
     Reactions to Sonic Booms," J. Aaoust.  Soa.  Amer., 39(5) 1966.

26.  Noise: Final Report, Committee on the Problem of Noise, Sir
     Alan Wilson, Chairman, Her Majesty's Stationery Office,
     London, July 1963.

27.  Geber, W., Anderson, T., Van Dyne, B., and Vermillion, S.,
     "Physiologic Responses of the Albino Rat to Chronic Noise
     Stress," Arch.  Environ. Health, 12:751, 1966.

28.  Dougherty, J., in "Human Response to Sonic Booms: A Research
     Program Plan," PAA Report No. 70-2, 1970 (BBN Report No.
     1831).

29.  Woodhead, M.M.,  "Effect of Brief Loud Noise on Decision
     Making," J. Aaoust. Soa. Amer., 31(10):1329-1331, 1959.

30.  Corcoran, D., "Noise and Loss of Sleep," Quarterly J.  Exp.
     Psych.  (14) 1962.

31.  Bureau of the Budget, Standard Metropolitan Statistical Areas,
     1967.

32.  Bureau of the Census, Statistical Abstract of  the United
     States,  1970.

33.  Business  and Defense Services  Administration,  Construction
     Review,  April 1971.

^.  Highway  Statistics/1969, U.S.  Dept.  of  Transportation,
     Federal  Highway  Administration, Washington,  D.C., Table  OMB,
     p.  167-

35.  Bureau  of the Census,  U.S.  Census of Population,  1,  I960.

36.  Wiener,  P.M., Malme,  C.I.,  and Gogos,  C.M.,  "Sound  Propaga-
     tion in  Urban Areas,"  J. Aooust.  Soc.  Amer.,  37, 1965.

37.  Noise  in Urban and  Suburban Areas:  Results of Field Studies,
     BBN Report  1395, 1967.
                               187

-------
REFERENCES (Continued)
38.   Department of Agriculture information based on studies of
     home activities (a long-term interest, which is now being
     continued under the Agriculture Research Service Division
     of the Department of Agriculture).

39.   New York State College of Human Ecology, Cornell University
     (both published and unpublished data gathered as part of a
     1296-household survey of Syracuse, New York).
                              188

-------
APPENDIX A - DETAILED SOURCE CHARACTERIZATION

A.I  Construction Equipment
     Of the considerable body of data on the noise of construction
equipment3 most pertains to the operator position; the available
data on noise radiated by this equipment to its surroundings is
very limited.  The data presented in Fig. 1 (main text) and in
this appendix were obtained from

   • The open literature [-Z-4]..
   • Reports, including those submitted by various manufacturers
     at the EPA hearings on construction equipment held in
     Atlanta, Georgia, July 8 and 9, 1971.
   • Field measurements conducted for this project at a number
     of construction sites in the vicinity of Boston.*

A.I.I  Noise spectra
     Much of the equipment used at construction sites is powered
by diesel engines, which generally constitute the predominant noise
sources.  Figure A.I shows the envelope of the 1/3-octave band
spectra of noise from 23 different items of diesel-powered con-
struction equipment, rated from 45 to 770 hp and  operating at
between 1100 and 2700 rpm, at a variety of conditions  (i.e., with
various degrees of loading, ranging from none to  heavy).  These
spectra were obtained at various locations around the equipment
items, which also varied in the degree of exhaust muffling present.
iPfhese measurements were made with a 1-in. Bruel and Kjaer type
 4131 condenser microphone, coupled to a Bruel and KJaer type 2203
 sound level meter.  The signals were recorded on a Kudelski Nagra
 type III tape recorder, and later analyzed in the laboratory by
 means of a General Radio Corp. "Real-Time Analyzer".  Calibration
 was accomplished with the aid of a Bruel and Kjaer type 4220
 piston phone.
                              A-l

-------
       Figures  A. 2,  A. 3,  and  A J-l  show  the noise  spectra from some
  typical  engine-powered  items  of equipment.  The  low-frequency
  peaks  typically correspond  to the firing frequency  (the number
  of power strokes per unit time  - which depends on the engine
  speed, number of cylinders, and  on the number  of power strokes
  per revolution) and its harmonics.  Figure A.2 illustrates the
  noise made by two tracked bulldozers under various working con-
  ditions.   These spectra reflect not only the diesel noise but
  also some noise due to tracks, gears, and scraping of metal
  components  against rock.

      Gasoline  (spark-ignition) engines  have noise spectra that
 are similar to those of diesel engines.   In construction  equip-
 ment,  however,  diesel engines  tend  to be  used  for all of  the
 higher power applications,  with  spark-ignition  engines  relegated
 to lower  power equipment.   Spectra  corresponding  to  two types of
 gasoline-engine  powered  equipment are shown in  Fig.  A.3.  '
     Noise  spectra  for  two  air compressors  - one  diesel,  one
 gasoline-engine  powered  - incorporating no  special noise  control
 provisions  are shown in  Fig. A.4.  Figure A.5 shows  the noise
 spectra associated with  several  pumps and generators; Fig. A.6
 shows  those levels produced  by a  vibrator acting  on  a plywood
 framework and by various saws  cutting wood.  Noise spectra pro-
 duced by various pneumatic tools  are  shown  in Fig. A.?.
     The noise from  conventional pile drivers is  characterized by
 intense peaks associated with the impacts of the hammer against
 the pile.   The peak  levels associated with these impacts are  indi-
 cated in Fig.  A.8 for two conventional pile drivers, together
with the noise  levels produced by a sonic (vibratory, nonimpact)
pile driver.
                              A-2

-------
A.1.2  Average construction site noise pollution levels
     Based on an analysis of the activities that occur during each
phase of construction at the various types of sites, a listing of
the equipment active during each phase was developed.  This list-
ings together with an estimate of the fractional number of sites
that involve each equipment item, appears in Table A-l.
     For site noise analysis, this large table was simplified by
averaging equipment usage over similar sites and by grouping to-
gether equipment items with similar noise characteristics.  For
the calculations, equipment with noise characteristics that were
not known directly was replaced by equipment expected to have simi-
lar (known) noise characteristics (e.g., back fillers and trenchers
were replaced by backhoes and loaders).  Equipment known to be
extremely quiet (e.g., electric cranes, electric fork lifts) was
totally omitted from the calculations.
     Since a given item of equipment is present at only a fraction
of all sites and only during part of each phase, and since it only
operates part of the time that it is present, a usage factor was
assigned to each equipment item.  This factor was calculated as
the product of three factors:  (1) the fractional number of sites
at which the equipment is used (based on Table A-l), (2) the esti-
mated fraction of the phase duration during which the equipment is
on site and (3) the duty cycle, i.e., the fractional time that this
equipment is operating while on site [5].  The resulting usage
factors are summarized in Table A-2.
     In order to calculate the site NPL, defined as the sum of the
energy-average SPL in dB(A) and 2.56 times the Standard Deviation
of A-scale SPL £6], one needs to know not only the average sound
                              A-3

-------
            TABLE  A-l.   USE OF EQUIPMENT  AT  CONST RUCT!ON SI If i
Type of
q p
Breaker, Paving
Burner, Aspl rated
Conveyor (Electric)
Crane
Climbing (Electric)
Crawler-Mounted (Diesel)
Truck-Mounted (Diesel)
Drill
Rotary
Pneumatic , Rock



Grad«r
Hamper, Plie-Drlvtng
Mixer, Concrete
Paver
Pump
Water (Electric)
Concrete (Diesel)
Wellpoint (Electric)
Ripper, Earth & Rock
Roller
Saw, Pavement
Sandblaster
Scraper
Screed, Vibrating
Shovel
Truck - Mounted

Crawler - Mounted
Sweeper
Tamper (ram)
Tools
Pneumatic , Impact
Hammer
Saw (Electric)
Tractor
Wheeled
Crawler
Backhoe
Dozer
Loader
Trencher
Truck
Dump, Off-Highway
!>u;np, On-Hlghway
Mixer, Concrete
Flat-Bed
Vibrators , Concrete
Warning Devices
Other
Chain Saw
Explosives


Domest
One to Four
Fa-niJy
Dwellings
[X]'
[X]5
[ X ] 3 ' •£




rx-jj , 5
rxi; ' =•



( X ) '


[X] !

(X ) 2 ' *
m>-'3

(X)'

[X] i - '
(X) 3 '1






(n, )U)1' =
(m ) X!-'-s
( 1 y3 j k 1 S

IV \ 1 , 2 , S
Y I . * , S
[X]"1'5
y 1 , 1 , E
X ' "- ' 5


X-' 5

x

(X)1


c Housing
Fi ve or More
Family
Dwel 1 ings
(S180-7ZOK)*
(X)1
IX]*,*
X- ' 5


?:;;
r v i f °
• 12 ,i



( X ) '
rxp

CM"

( ^ S XJ ' '
,.,,,

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Office Bui Iding ,
Hotel , Hospital
( S190-4 .OGOKJ*
(X)s
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mt
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fX)"'l
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(m?) X ' '^'s
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(rti,1:) >.
(ill ) A


ry-,1,2

Nonres ident
School , Publ ic
Works Building
($280-1 ,090K)*
Y2 , ) , . ,i
(X)3 "• 'S.

(m£ ) (X )-
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(X) ' •!' !
x j , ; , 5
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mDlX:1 '^'s
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[Y1,,,

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Industrial ,
( S120-820K)*
[X]4
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Xi,s,,,s
(rTl2KX)~'S

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tional. Store,
(S30-400K)"
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(X)s
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(in?) x1-'^'3'-'5
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(in ) X'" 'I"
(ill ) X1'"-3-'1
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(Hi ) X ' ' 2 ' 3 " ' 5

(-1 ) :•:'

c Uorks
Municipal
Sewers and
Trenches
X'
(x)'''-i'
x!,,,,,,


X'

(X)'
(X)2


Xi,,,,,..,
(X)

(J,l,,,,
x--i

(m?) X3'i"

-------
            TABLE  A-2a.   USAGE  FACTORS  OF EQUIPMENT

                IN DOMESTIC HOUSING CONSTRUCTION*


Equipment"''                         Construction Phase

Air Compressor
Backhoe
Concrete Mixer
Concrete Pump
Concrete Vibrator
Crane, Derrick
Crane, Mobile
Dozer
Generator
Grader
Jack Hammer
Loader
Paver
Pile Driver
pneumatic Tool
Pump
Rock Drill
Roller
Saw
Scraper
Shovel
Truck
•i- n
f~ >
fO 0}
HI 0
i— X
O Ul
[81] .1
[85] .02 .04
[85]
[82]
[76]
[88]
[83]
[80] .04 .08
[78] .4
[85] .05
[88]
[79] .04 .08
[89]
[101]
[85]
[76] .4
[98] .01
[74]
[78]
[88] .05
[82] .02
[91] .16 .4
Founda


.4











.04
.7


.04



                                   o        o                 CD
                                                     4->        Ul
                                                     O        T-
                                                     o;        e
                                                             .25
                                                             .02
                                                     .08      .16
                                                     .1        .04
                                                              .04


                                                              .02

                                                              .025
                                                              .04

                                                              .025


                                                     .1        .04


                                                              .005
                                                              .04
                                                     .1(2)     .04(2)
                                                              .01


                                                              .16
 * Numbers in parentheses represent average number of items in use,
   if that number is greater than one.  Blanks indicate zero or
   very rare usage.


 t Numbers in brackets [ ] represent average noise levels  [db(A)]
   at 50 ft.

                                A-5

-------
            TABLE A-2b.  USAGE FACTORS OF EQUIPMENT

                 IN NONRESIDENTIAL CONSTRUCTION*
Equipment1"

Air Compressor
Backhoe
Concrete Mixer
Concrete Pump
Concrete Vibrator
Crane, Derrick
Crane, Mobile
Dozer
Generator
Grader
Jack Hammer
Loader
Paver
Pile Driver
Pneumatic Tool
Pump
Rock Drill
Roller
Saw
Scraper
Shovel
Truck

01
•r—
03
O)
[81]
[85] .04
[85]
[82]
[76]
[88]
[83]
[80] .16
[78] .4(2)
[85] .08
[88]
[79] .16
[89]
[101]
[85]
[76]
[98]
[74]
[78]
[88] .55
[82]
[91] .16(2)
Cons
0
4->
ra
ra
u
X
UJ
1.0(2
.16





.4
1.0(2

.1
.4



1.0(2
.04



.4
.4
truction Phase
c
0
4->
ra
-a
e
3
o
U-
) 1.0(2) 1

.4
.4
.4



)

.04


.04
.04
) 1.0(2)


.04(3) 1




c
0
•p
u
OJ
UJ
.0(2)

.4
.08
.1
.16
.16(2)



.04



.16(2)
.4


.0(3)




c
•r-
.C
10
c
•r-
LJ_
.4(2)
.04
.16
.08
.04
.04
.04(2)
.16

.02
.04
.16
.1

.04(2)

.005




.16
* Numbers in parentheses represent .average number of items in use,
  if that number is greater than one.  Blanks indicate zero or
  very rare usage.


"*" Numbers in brackets [ ] represent average noise levels [db(A)]
  at 50 ft.

                               A-6

-------
Equiptnen
    TABLE A-2c.   USAGE FACTORS OF EQUIPMENT

           IN INDUSTRIAL CONSTRUCTION*



t"t"                         Construction Phase
                            c       c
                            O       O
                  CD         •!-       T-
                  C         •!->       -P




Air Compressor
Backhoe
Concrete Mixer
Concrete Pump
Concrete Vibrator
Crane, Derrick
Crane, Mobile
Dozer
Generator
Grader
jack Hammer
Loader
paver
pile Driver
pneumatic Tool
pump
RoCk Drill
Roller
Saw
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# Numbers  in parentheses  represent.average number of items in:use
  if that  number  is  greater than one.   Blanks indicate zero or    '
  very rare usage.


t Numbers  in brackets  [  ]  represent average noise levels [db(A)]
  at 50 ft.                                             .
                               A-7

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            TABLE A-2d.   USAGE FACTORS OF EQUIPMENT
                  IN PUBLIC WORKS CONSTRUCTION*
Equipment"1"
Construction Phase
                                    c
                                    o
                                    to
         c
         o
                                            
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pressure, but also enough about its time-variation so that  one can
determine its standard deviation.  In addition, the background
noise levels enter in the evaluation of both of these quantities.
Accordingly, representative background noise levels were selected
as 50 dB(A) for residential, suburban, and rural sites and 70 dB(A)
for commercial and industrial (urban) sites, on the basis of data
for various U.S. and foreign locations [?].
     Representative time-variations of noise were generated by
dividing each construction phase into 50 equal time intervals.
The start (or "turn-on") times for each individual item listed in
Table A-2 were determined at random  (by means of a computer
random number generator), and the fractional "on-time" duration
for each item was taken as its usage factor  (Table A-2).  Prom the
noise level for each item of equipment, the  total noise level in
each time interval was then calculated, and  from this ensemble of
values the desired average and standard deviations were evaluated.
For test purposes, the calculations  for several sites/phases were
repeated several times, with different randomly selected start
times; the resulting NPL values  were always  found  to  lie within a
3 .dB(A)  interval.  Although such repetitive  calculations were not
carried  out for all sites/phases, the reported site NPL values may
   considered as valid within  ±2 dB(A).
A. 2   Appliances
      In  the  following  sections,  brief  discussions  are  presented
Of appliances  not  covered  in  the body  of  the  report.   We  measured
the  noise  levels of  many of these appliances;  these measurements
 re  presented  here as  1/3-octave band  sound pressure data.
                               A-9

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 A.2.1  Can opener, electric
      Noise of electric can openers is generated by the reducing
 gear3,  the electric motor, and the grating of the  clamp against
 the  moving lip of the can.  Additional noise  is radiated from  the
 plastic or metal panels  of the unit.   Can  openers  are  usually
 mounted on small rubber  feet which partially  isolate the vibration
 from the work surface; however,  wall  mounting of the opener  can
 short-circuit  this isolation.   The A-weighted sound level  at a
 distance of 3  ft was  measured  for  seven  electric can openers;  the
 mean level was  66  dB(A).
      Figure A.9  shows  1/3-octave band plots of  the sound pressure
 levels  measured  at  a  distance  of 3 ft  for  two different  can  openers
 The  peaks  at  63  and  125 Hz are probably  motor-induced  while  the
 higher  frequency peaks are probably related to  the number  of teeth
 in the  reducing  gears.

 A.2.2   Clothes dryer
     Clothes dryers are relatively quiet appliances which  consist
 of a rotating drum within  a metal  enclosure; heat is supplied  by
 either electric  coils or a gas flame.  The constant noise  of the
motor and the rumble of the drum,  plus the combustion  roar in  a gas
dryer, are punctuated by the noise of buttons or zippers impacting
with the metal chamber.  A range of sound levels from  51 dB(A)  to
66 dB(A), with a mean level of 58 dB(A), was measured  at a distance
of 3 ft  for eleven gas and electric dryers.  Figure A.10 shows
1/3-octave band sound pressure level data for five  different  dryers.
                              A-10

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A. 2. 3   Clothes washer
     The noise generating components of clothes washers include:
    • water noise during the filling, agitation, and spinning
     cycles
    • unbalanced loads, which cause excessive vibration to be
     transmitted into  piping and  floor
    • motor
    • pump
     Figure A. 11 presents the noise levels for the wash cycle of
five different machines; Fig. A. 12 shows noise lev*ls for the spin
cycle of four of these five machines.  The peaks in the low-
frequency bands probably represent motor-induced noise while those
    the  mid-frequency bands may be related to spinning of the tub.
A. 2. 4  Coffee mi 1 1
     A coffee mill consists of a grinding mechanism that is driven
by a. motor to produce fine to coarse ground coffee.  Motor-induced
noise is radiated from the casing and the coffee bean enclosure.
pubber feet are provided for vibration isolation.  Measurements
were made at a 3  ft distance on two coffee mills:  the two sound
levels were 75 dB(A) and 78 dB(A).

A. 2. 5  De humidifier
     In a home humidifier, a small fan draws air across condensing
coils* collecting the moisture in a removable pan.  Noise measure-
ments were made of four dehumidifiers; the noise varied from
52 dB(A) to 62 dB(A).
                               A-ll

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     Figure A.13 present 1/3-octave band data for the quietest of
these units.  The broad peak in the vicinity of 120 Hz is motor
induced; mid-frequency noise is dominated by the fan.  Although
compressors may be vibration isolated, the casing of a unit is
likely an important radiator.

A.2.6  Edger and trimmer
     An edger and trimirk,^ consists of a high-speed motor directly
driving a two-bladed knife.  This lawn tool is used to trim the
gra.'.s along walkways and the brush along garden paths.
     Figure A.14 presents 1/3-octave band data on one unit; the
sou;.d level was bl dB(A).  The peaks in the frequency spectrum
seem to be the 1st, 2nd, 3rd, 6th, and 20th harmonics of 400 Hz.
It is anticipated that narrower band analysis would reveal more
tonal components that are related to the blade passage of the
cutMng edge.

A.2.7  Fan
     There are three general categories of fans found in the home:
window fans, floor fans, and stove hood and bathroom exhaust fans.
   • Window fans are usually standardized to a 14-in. or 22-in.
     size (12-in. and 20-in. diameter blades respectively).
     Features on deluxe models include thermostatic control and
     reversible direction of air flow.  Twelve noise measurements
     of window fans ranged from ^7 dB(A) to 66 dB(A); the mean was
     57 dB(A).  Low-speed to high-speed mean values showed a spread
     of 17 dB(A).
                               A-12

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     Figure A.15 presents 1/3-octave band noise measurements for
three window fans for both low and high speed.  The tonal compo-
nents are likely related to the blade passage frequency of the
fan, the motor, the blade tip velocity, and the blade design.
    • Floor fans or table fans usually consist of a base, a small
     electric motor, and a blade with protective cage.  They often
     rotate back and forth to spread air movement around an arc
     of 90° or so and are usually designed to run at various
     operating speeds.  Twenty-two measurements at a 3 ft distance
     yielded a range of sound levels from 38 dB(A) to 67 dB(A)j
     the mean level was 5^ dB(A).
     Figure A.16 presents 1/3-octave band data for three floor  fans
for both low and high speed.  The noise sources are very similar
to  those of window fans.
    • Stove hood exhaust fans and bathroom exhausts are typically
     small axial flow fans mounted directly above the stove  to
     exhaust cooking odors or in the bathroom ceiling to exhaust
     hot air.  The mean dB(A) level of ten measurements at  a
     3 ft distance was 63 dB(A).
     Figure A.17 presents narrowband data for four speeds for  one
particular stove hood exhaust fan.  Again, the tones are related
to  motor noise and blade passage fan noise.  Through the use of
appropriate lining it should be possible to reduce the noise of
stove hood exhaust fans and bathroom exhaust fans by up to  15  dB(A)
                               A-13

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A.2.8  Food blender
     The electrical motor control system on food blenders is de-
signed to drive the cutting blades (located at the bottom of a
removable container) at a wide range of speeds in order to perform
various food blending tasks.   Speed control may be achieved by
using a variable-speed motor or solid state electronic networks.
The primary sources of noise are the motor, the whirling of the
blades causing radiated noise, structureborne noise, and agitating
noise of the fluid.  From measurements of the noise generated by
foreign and domestic food blenders, the sound level ranged from
62 to 88 dB(A) with a mean level of 75 dB(A).  The container was
half full of water during most of these measurements.  Figure A.18
presents a series of narrowband measurements representing the noise
levels generated by one food blender running at each of nine dif-
ferent speeds.  The peaks in the spectrum shift upward in frequency
with increased speed, suggesting a dependence on the blade passage
frequency of the cutting edges.  Figure A.19 shows the variation
in noise level for a maximum speed setting for five food blenders
of different manufacture.

A.2.9  Food mixer
     Food mixers are available in both portable and table model
styles.  Portable mixers are lightweight versions of table models -
they have no base but consist of the same basic mechanisms:  a
set of beaters and a variable-speed motor or a single-speed motor
with reduction gears.  Twenty-five sound level measurements were
made at a 3 ft distance on domestic and foreign, portable and
table model food mixers.  The mixer was operated in a bowl half-
full of water for most of the measurements.  The sound level ranged
from 49 dB(A) to 79 dB(A) with a mean level of 67 dB(A).  Figure
A.20 shows narrowband analysis of mixer noise at low speed and  at
high speed.
                               A-14

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A.2.10  Freezer
     The mechanical components of a freezer are a compressor,
evaporative coils, condensing colls, and one or two fans,  as  in
a. refrigerator.  Small freezers have the condensing coils  spread
over the back of the machine.  On larger units, with their require-
ment for forced cooling, the condenser coils are grouped at the
bottom and cooled by a fan that also cools the compressor.  With
the compressor in operation, the sound levels generated by three
home freezers were measured; the mean level was 4l dB(A) with a
range of 39 to 4 5 dB(A) at a 3-ft distance.  Figure A.21 shows
narrowband data for two of the three freezers.  The primary noise
generators are the motor, fans, and compressor, with some radiation
from the casing.

A.2.11  Hair clipper
     A measurement of the noise generated by a hair clipper was
made at a distance of 3 ft; the sound level was 59 dB(A).  The
noise is generated by the motor and gears which enable the clipping
Blades to vibrate.

A.2.12  Hair dryer
     Different models of hair dryers all share the design  ob-
jective of forcing warmed air over  wet hair.   Table models have
  hard-shelled enclosure like that  of a professional hairdressers
machine.  Portable dryers have plastic bonnets connected  to the
fan and heater by a flexible hose.  Noise  is  generated  by  the
fan, motor and air flow.  A  faster  drying  rate is  achieved by
greater air flow  and higher  temperatures;  this, however,  means
increased noise from the fan.  The  latest  development  of  a
totally portable  unit - with motor  and blower attached directly
to  tne bonnet ~ ls tne  noisiest  arrangement because  it  puts
fche noise source  directly by the  ear  of  the user.   Six hair
                               A-15

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dryers were measured at a 3-ft distance; the mean level was
61 dB(A).  Figure A.22 shows 1/3-octave band sound pressure
levels measured at a distance of 3 ft from three units.  The
low-frequency tonal components are probably motor related, while
the high-frequency peaks may relate to the blade passage of the
blower.

A.2.13  Heater, electric
     Electric heaters used to heat a single room typically have
small single-speed fans that blow air past electric coils into the
room.  The noise generated by these heaters is due to the electric
motors, the fans, air flow, and, often, rattling metallic parts.
A noise level of 4? dB(A) was measured at 3 ft from an electric
heater.

A.2.14  Hedge clippers
     The noise of hedge clippers, in which an electric motor runs
one or two cutter bars, is mainly generated by the motor and recip-
rocating gear action.  On some models, one bar moves back and
forth against a stationary bar; on other models, two cutters recip-
rocate.  Since the latter is a more balanced action, vibration to
the user is reduced.  We measured a noise level of 84 dB(A) at
3 ft from one unit.

A.2.15  Home shop tools
     Electrically-powered shop tools such as drills, saws, sanders,
grinders, lathes, and routers have similar noise generating mecha-
nisms.  In general,  portable shop tools, due to their requirement
to be lightweight and high-powered, require forced cooling of the
motor and use high-speed universal motors which are often noisy
                              A-16

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even when running free.  Table model shop tools generally use
induction motors which are relatively low speed and quiet when
running free.
     The portable straight-line or vibration sander is relatively
quiet when running free [63 dB(A) at 3 ft] because it has a lower
power requirement than most power tools and requires no forced
cooling.  Figure A.23 shows narrowband data for two operations
Of a belt sander:  running free [82 dB(A)] and sanding wood
[86 dB(A)].  The primary noise is the vibrating action of the
sander foot.
     In drills the gears add to the noise - the more sets of gears
required, the noisier the operation.  The noise generated by four
1/4-in. drills with a single set of gears measured 76 to 80 dB(A),
the noise of two 3/8-in. drills with two sets of gears measured
83 dB(A), and the noise of two 1/2-in. drills with three sets  of
gears measured 84 and 8? dB(A).  Figure  A.24 presents noise  levels
measured near a  1/4-in., a 3/8-in., and  a 1/2-in. drill; the peaks
in the spectrum  are probably related to  the speed and the teeth
ratios of the gears.  Figure A.25 presents narrowband data on  two
different drill  presses, one working metal, the other wood.
     Noise  levels generated by three different grinders  working
metal  [87 to 97  dB(A)]  are shown in Fig. A.26.  In Fig.  A.27 the
noise  levels generated  by.a. router running free  [81  dB(A)] are
compared with the  levels when  it is working wood  [88 dB(A)].
Noise  levels of  a  small metal  lathe  are  shown  in  Fig. A.28 for a
running  free condition and for cutting metal.  Figure A.29 shows
£he,,narrowband .dat.a  for a- ,sabr,e_s.aw,..running,, free  and! cutting wood..
                                A-17

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Noise levels associated with the cutting of wood by a jig saw, a
radial saw, a table saw, and a band saw are shown in Fig. A.30.
The tone at 3150 Hz for the table saw may correspond to the fre-
quency of teeth passing a given point [g].
     Tools such as a table grinder, lathe, table jig saw, and table
band saw generate noise levels in the mid-sixty to mid-seventy
dB(A) range at a 3-ft distance while running free.  The larger
portable tools especially drills and grinders, generate noise
levels of 80 to over 90 dB(A) running free.

A.2.16  Humidifier
     Room size humidifiers are relatively simple mechanical devices
in which a fan forces air through a wetted pad.  Humidifiers ex-
emplify the recurring noise problem from air circulation caused by
fan, motor, and air movement noise.  Figure A.31 shows narrowband
data - 41, 51, and 65 dB(A) - for three settings of one humidifier.
The higher levels are associated with higher fan speeds and thereby
increased flow noise.

A.2.17  Knife, electric
     For easy handling in the home, electric knives are designed
to be small and lightweight.  Therefore, the electric motor and
gears for reciprocating blade action are encased in lightweight
plastic.   While the noise of an electric knife [with a range of
65 to 75  dB(A) and a mean level of 70 dB(A) at 3 ft] can be annoy-
ing, it also acts as a signal that the knife is in operation.
Figure A.32 shows narrowband data for two of the three samples.
                              A-18

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A.2.18  Knife sharpener
     Electric knife sharpeners are often attached to electric  can
openers as well as being separate appliances.   The rotation of
sharpening stones alone is very quiet since just the motor and
shaft rotate; however, the interaction between the stone and the
Knife during the sharpening process makes an unavoidable grating
noise.  A single measurement was made at a 3-ft distance; while
the noise levels vary depending on the pressure of the knife
against the stone, 72 dB(A) is representative of a typical
sharpening operation.

/\.2.19  Lawn mower, electric
     The gears and the A.C. or battery powered engine of the rotary
type electric lawn mower are the main sources of noise.  The rattl-
ing of the engine housing and other metal parts plus the whirling
sound of the blade are also identifiable.  Although an electric
lawn mower is often quieter than a gasoline-powered lawn mower,
the two electric ones that were measured registered 81 and 89 dB(A)
at a 3-ft distance.  The larger the lawn mower, the more powerful
an engine is needed to rotate the blade, and thus the noisier the
device.  Certain possibilities appear feasible for quieting the
electric lawn mower such as changes in blade design and speed
to reduce vortex noise, tighter construction of the tool, and
sound damping for the motor housing and blade covering.

A.2.20  Oral lavage
     An oral lavage is a device that uses the squirting force of
water to cleanse the mouth.  The motor drives a reciprocating pump,
connected to a water supply, which forces a tiny stream of water
out the end of a tube.  Two measurements gave values of 70 and
72 dB(A).
                              A-19

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A.2.21  Refrigerator
     The majority of the refrigerators sold today are automatically
defrosting.  Cooling coils are located outside the freezer storage
area and cold air is circulated through the freezer unit by a fan.
The automatic defrost mechanism periodically melts the ice which
forms on the coils.  The trend in recent years has been to larger
refrigerators with features such as automatic ice cube tray fill-
ing, ice cube making, and defrosting.  Refrigerators with such
features require more power and thus larger compressors with result-
ing higher noise levels.  Better sound isolation around the
machinery compartment, sound absorbing material in the machinery
compartment, and resilient mounting of the motor and compressor
have prevented the noise of the newer machines from greatly increas-
ing.  Twelve refrigerators were measured at a distance of 3 ft
from the front.  The levels ranged from 35 dB(A) to 52 dB(A) with
a mean level of 42 dB(A).  Figure A.33 presents narrowband data
for two refrigerators.

A.2.22  Sewing machine
     Sewing machines from the simplest to the most sophisticated
and complex ones all have variable-speed electric motors, necessary
gear and drive mechanisms, and auxiliary accessories.  There is a
wide range of .controls available such as stitch tension, variable
stitch length and width, zig-zag stitching, forward-reverse action,
needle orientation, etc.  The more versatile sewing machines have
insertable cams which can be changed for different stitching pat-
terns.  Measurements on two sewing machines in operation gave
values of 70 dB(A) and 7^ dB(A) measured 3 ft from the machine.
Figure A.3^ shows narrowband data for these two machines.
                              A-20

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possible noise control measures are to reduce noise from the" motor,
linkages, gears, and clutch by use of different materials and more
effective enclosures.  Resilient mounting of vibrating parts to
Deduce structureborne vibration noise is presently used.

A.2.23  Shaver, electric
     Electric shavers are run by a compact but powerful electric
motor, powered from house current or a rechargeable battery.  While
shaving mechanisms may vary — using either rotary blades or oscil-
latory cutting action — the noise is generated by the motor and
gears.  The mean sound level for men's and women's shavers was
60 dB(A) at a 3 ft distance; the range was 4y to 69 dB(A).  Figure
£.35 shows narrowband data for four men's shavers and Fig. A.36
presents data for two women's shavers.

A.2.24  Toothbrush, electric
     A small, lightweight high-speed motor run by either A.C. power
or rechargeable batteries drives the detachable toothbrush.  The
less expensive models allow rotation in only one plane  perpendicu-
lar to the axis of the toothbrush.  With additional gearing, the
more expensive models simultaneously rotate and move laterally to
provide better cleaning action.
     The main noise sources of an electric toothbrush are the motor
and the gears.  Typically, the devices with more gears  are noisier.
rjhe mean sound level of three different electric toothbrushes at a
3 ft distance in bathrooms was 52 dB(A) with a range of 48 to
55 dB(A).  At the user distance of about 3 in. from the device,
the sound level is about  10 dB(A) higher.  Figure A.37  shows
narrowband data for an electric toothbrush.
                               A-21

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     Due to the overriding requirements for small size and light
weight, noise control techniques such as improving the sound trans-
mission loss of the casing or adding sound absorptive material are
impractical.  The most promising noise reduction possibilities will
likely come from the development of quieter gear operations through
the use of different materials or through designing the gears with
closer tolerances or a different configuration.

A.2.25  Water faucets
     Noise from water faucets includes water hammer, turbulence
and cavitation noise.  For particular values of pressure drop, a
valve can be designed to minimize cavitation and its resulting
noise; however, no valve configuration has been developed to
minimize the noise for the full range of pressures that a valve
experiences.  The measured sound level at a distance of 3 ft for
two water faucets was 61 dB(A).  If die-casted brass fittings could
replace sand-casted ones, there would be a smoother interior finish
which would result in less turbulent flow and quieter operation.

A. 3  Typical Equipment in Buildings
     Many different types of electrical and mechanical equipment
are required for the proper operation of modern large buildings.
Much of this equipment is hidden in equipment rooms, behind ceil-
ings, in walls, or behind cabinet type exterior enclosures, but the
total cost and volume associated with such equipment represents a
significant part of the cost and utility of a successful building.
The majority of the equipment (including most of the basic heating
and cooling system components) is for supplying the building occu-
pants with a suitable amount of air at a comfortable temperature
and moisture content.   In addition, pumping and piping systems are
                              A-22

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used for water and fluid circulation, elevators and escalators  are
used for movement of persons, and various conveyance systems are
used for movement of material.  In this section, the use and func-
tion of building equipment are briefly described.   Where available,
typical noise levels are presented for the equipment.   For. detailed
information and procedures, the reader is referred to Refs.  9,  10,
11, and 12 at the end of this Appendix.

A. 3.1  Prime movers
     The function of prime movers is to transform energy — in the
form of electric power or combustible fuel — into rotational move-
ment for use in driving other equipment.

     EleotTic Motors are the most widely used of the prime
mover devices.  They range in capacity from fractional hp
up to several thousand hp; most motors fall in the speed range
Of about 450-3600 rpm.  Motor noise is generated by aerodynamic,
mechanical, and electrical forces.  Aerodynamic noise, often the
most prominent noise source, is generated by air turbulence due to
movement of the blades of the cooling fan and the slots in the
rotor.  Recent designs have used higher cooling air velocities,
thereby increasing the noise level.
     Mechanical noise is due to bearings and shaft unbalance.  Al-
though mechanical noise can be identified in rotating machinery,
low-frequency vibration rather than noise per  se  is the usual
problem.  Bearing noise is due to the sliding contact of sleeve
bearings and the rolling contact of ball and roller bearings.  When
new, precision ball bearings are often quieter than sleeve bearings;
however, after much use, they are much noisier.  In new equipment,
unbalance forces are usually small.  Wear or build-up of dirt on
the rotating component often increases the unbalance in a motor,
                               A-23

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resulting in the generation of vibration at the rotational fre-
quency and its integral multiples; e.g., since the shaft of a
3600 rpm motor turns at 3600 rpm f 60 ^1^- = 60 ?—., energy will be
                                      1711 n      S G C
concentrated at 60, 120, 180 Hz, etc. with the 60-Hz component
being the strongest .
     Electrical noise is generated by magnetostriction — where a
component (iron laminations) contracts and expands in response to
an alternating magnetic field.  Such effects are particularly
noticeable when B.C. or variable-speed motors are supplied recti-
fied A.C. current.  The wave-form of the rectified current contains
high-frequency components that generate noise in the more audible
frequency ranges.  The primary excitation frequency for magneto-
striction is twice the main power frequency, e.g., in the USA,
2 x 60 Hz or 120 Hz.
     In the past, motor noise was generally less than the noise
produced by the driven component.  However, motors designed for
high-temperature rises or powered by rectified current may now be
the controlling noise sources.  Even in the case of relatively
quiet motors, motor noise often becomes predominant when the driven
component is quieted.   Figure A. 38 presents a range of noise levels
typical of a 3 ft measurement position for the many different sizes
of motors used in buildings.

     Diesel and Natural or LP (Liquified Propane) Gas Internal
Combustion Engines are sometimes used when special conditions make
them economically feasible.   They are often used in emergency power
systems, in total energy systems, and for driving large machines
such as chillers,  Noise generated by internal combustion engines
consists of contributions from the intake and the exhaust and
radiation from the casing.   Although improperly muffled exhaust
may be a source of community concern, the intake and radiation from
                               A-24

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the casing are typically greater problems for buildings  and con-
siderable detail must be given to controlling the noise.   Figure
A.39 shows a range of noise levels measured at 3 ft from internal
combustion engines found in buildings.

     Gas Turbines are used almost exclusively in emergency power
and "total energy" systems.  A total energy system makes use of
the fact that only about 20-30$ of the heat energy of most fuels
can be turned into mechanical power; the rest is rejected in
the form of heat to  cooling water and exhaust gases.  A total
energy system salvages some of the energy which  is usually lost
and uses it to heat  water, etc.  The'advantages  of turbines
over equivalent internal combustion engines are  their light weight,
smaller size, and lower vibration, which can  be  governing  factors
for upper story installations.  Figure A.^0 presents noise levels
representative of the noise generated by gas  turbines.

     Steam Turbines  are sometimes used as high  horsepower  (over
50 hp) prime movers  when high-pressure steam  is available  as  a
pubic  utility service.  Figure  A.1!!  shows  the range  of  noise  levels
typically found near steam turbines.

     Transformers,  although their  function  differs from that  of
the  prime movers  listed above,  supply  primary electrical input
power;  their  output  is  an  altered  form of  electrical power (higher
amperage  and  lower  voltage) rather  than  motion.  The use of trans-
formers  permits  large amounts of electrical energy to be supplied
to a building with  relatively small  supply cables.  Noise generated
by transformers  is  due  primarily to  the  magetostrictive effect  in
the  transformer cores.   Thus, the noise  consists of a harmonic
series of component tones  with a fundamental frequency equal to
                                A-25

-------
 twice the main power frequency.  The range of noise levels gener-
 ated by transformers typically housed in buildings is presented
 in Fig. A.42.

      Generators or Converters are used to produce local electricity
 in emergencies when electrical power is unavailable from outside
 sources, to produce direct current electricity, or to convert
 power from one frequency to another.  The noise generating charac-
 teristics  and noise levels of generators are similar to those of
 electrical motors.

 A.3.2  Fluid handling  units

      Pumps  may be  the  common  centrifugal type  that uses an elec-
 tric  motor  drive,  or the  diaphragm or  piston or gear-rotor types
 that  are positive  displacement  units.   Many  of the pumps  in a
 building are part  of the  overall  air-conditioning system.   They
 convey water to and from  cooling  towers,  chillers,  boilers,  and
 coil  decks  in  airconditioners,  humidifiers,  unit  heaters,  unit
 ventilators,  and induction  units.   Pumps  may also be  used  to  supply
 fuel  oil to  boilers, domestic water to upper floors,  emergency
 fire-fighting  water, hot  water  for  various uses such  as convectors,
 ice melting, radiant heating, etc.,  and  for  sewerage  ejection from
 low levels.

     Noise problems due to pumps are usually caused by mechanical
 forces and turbulence.   Noise is radiated by the  casing of the
pump and associated piping.  In order to prevent  the tonal compo-
nents at the impeller passage frequency  (the impeller speed in
revolutions' per second  multiplied by the number of impellers) ..from
being detectable at remote locations, a vibration break of flexible
connections in the  piping is sometimes provided.  However, sound
                              A-26

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energy in the fluid may flank this flexible connection so  that  the
pipe walls are excited downstream of the pipe  break.   Figure  A.43
shows a range of noise levels typical of many  pumps  used in build-
ings.

     Steam Valves may be used either to control volume flow or  to
reduce the pressure from the main supply system.  A  steam  valve,
like any valve, is noisiest when there is a large pressure differ-
ential between the upstream and downstream of the valve.  A typical
spectrum for steam valve noise is presented in Fig.  A.44.

A.3.3  Air handling

     Fans are the driving mechanism for moving air about a build-
ing.  Propeller-type fans may be used to distribute  large  quanti-
ties of air at little pressure drop across the fan;  centrifugal
and axial-flow type fans may build up relatively large static
pressures in an air handling system and thus are used mostly
in ducted ventilation systems in large buildings.  In a ducted
system, the air will tend to flow toward regions of lesser
static pressure, eventually to be released at ambient pressure
in the building proper.
     Fan noise is generated by mechanical and aerodynamic sources.
Bearings and unbalanced shafts are the primary mechanical sources;
with proper construction and maintenance, fan noise from these
sources can be minimized.  Aerodynamic noise may be divided into
components due to rotation and due to vortex shedding.  Since an
impluse is imparted to the air each time a fan blade  passes a given
point, the rotational component consists of a series  of tones at
multiples of the blade .passage frequency (rotational  speed in
revolutions per second times the number of blades).    The vortex
                               A-27

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component is primarily the result of the shedding of vortices
from the fan blades; it is an example of broadband random noise.
Depending upon the type, size, and geometry of a particular fan,
the total noise generated will have varying contributions from
vortex and rotational noise.
     The horsepower, volume flow, and static pressure, and thus
the mechanical efficiency, are important indicators of the noise
that will be generated by a particular type of fan.  Figure A.45
shows estimated levels for a range of fans utilized in buildings.
The noise problems that do occur are usually due to either a
failure by the mechanical or acoustical system designer to consider
an important source or path,  or a failure of the builder to in-
corporate properly the designed noise control features in the
building.

     Air> Control Units and Mixing Boxes comprise a family of
supply air control and treatment devices that provide air at the
proper volume, pressure, and temperature to a room'.  These devices
include:  constant volume control (CVCs), terminal reheat units
(TRs), variable volume controls (VVCs), and dual duct mixing boxes.
Their function, in many instances, is analogous to steam valves -
they take air which has passed through a small duct at high
velocity and pressure and reduce its pressure and control its
volume flow.  A constant volume control takes in air at varying
pressure (caused by changing demands elsewhere in the system) and
discharges a constant volume of air at a constant pressure.  A
terminal reheat unit adds the capability of heating the air by
passing it over an electric or hot water coil before it is dis-
charged.  A variable volume control meters out an amount of heat-
ing or cooling air as demanded by a local thermostat and reduces
the static pressure of the air to obtain the desired volume.  Each
of these units is usually located toward the end of supply ducts
                              A-28

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near the space it serves.   Noise generated by air control units
and mixing boxes is a function of the pressure drop across the
device and the volume of air flow.  Figure A.46 presents a range
of noise levels typical of a 3 ft distance from these units.

     Diffusers, Grilles, Registers, and Louvers.  After a supply
of air at the correct pressure, temperature, and volume has been
provided to the vicinity of a room, it must be introduced and
distributed into the room without causing drafts.  Portions of the
air should be directed toward windows and other exterior surfaces
that are too cold in the winter and too hot in the summer, while
all the air should be distributed so as to provide ventilation to
all parts of the space.  This is done with various diffusing or
direction-controlling devices, usually fabricated from sheet metal,
consisting of fins, blades, vanes, etc., that are located at the
end of the duct.  Perforated grilles, registers, or other similar
devices are used to receive the air to be returned to the distri-
bution system.  The noise generated by terminal devices,  such as
diffusers, is dependent on the pressure drop  across the  device,
the volume of air flow, the cross-sectional  area, and the spacing
between vanes.  Figure A.47 illustrates the  range of noise levels
possible with various diffusers,  grilles, etc.

     Air Compressors are the source of high-pressure air which is
used by many large buildings as an energy source for pneumatic
control devices throughout the ventilation  system.  Such controllers
include fresh air intake dampers,  zone control  dampers,  induction
units, unit ventilators, mixing valves in mixing boxes,  and  control
valves in CVC and WC units.  The  high-pressure  air provided by
the compressor must be piped throughout the  building,  first  to
thermostats and then to the pneumatic operators.  Buildings  which
                               A-29

-------
have laboratory or workshop facilities usually supply compressed
air to those spaces.  Air compressors are most often of the piston
type and, depending upon the size of the unit, the reciprocating
action of this type of compressor may make satisfactory vibration
isolation difficult.  Figure A.48 is an example of noise levels
generated by reciprocating compressors.

A.3.4  Airconditioners
     The usual functions of an airconditioner are to filter par-
ticulate matter and odors from the air, to regulate air tempera-
ture and humidity, and to propel the conditioned air to its desti-
nation.  The fan in the airconditioner serves two purposes:
1) to move the air through the filters and heating and cooling
coils, and 2) to provide enough static pressure to push the air
throughout the duct system to the desired spaces.  The heating and
cooling coils are liquid-to-air heat exchangers, receiving warm or
cold water or refrigerant from other machines and transferring
warmth to or from the air carried past them.

     Central Station.   Strictly speaking, "central station" refers
to the entire collection of equipment that has a part in condition-
ing the air that is ultimately distributed to the building.  In its
more limited use here, "central station" refers to the fan plenum
equipment of the airconditioner.   The equipment includes controllers
and filters on the inlet side and heating and cooling coils, and
temperature controllers and, possibly, zone controllers on the
discharge side.  The cooling coils act as dehumidifiers in that
warm, moisture-laden air condenses on them.  Occasionally, a humid-
ifier is incorporated to add humidity for special needs.  Central
station units are most common in large multistory buildings.  The
size of a particular unit will depend upon the service that it is
supplying.  Noise levels for units typically found in buildings
are presented in Fig.  A.49.

                               A-30

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     Unitary Rooftop Units are usually found on one- or two-story
buildings.  They perform the same function as the larger central
station units but do not rely on other machines to provide hot  or
cold fluid to their heating and cooling coils; in other wordSj
these units include their own compressors, condensers,  etc.   In a
large one-story building or building complex, this can  represent
a savings on the heating and cooling water piping which would be
needed if the units were dependent on other machines.  Figure A.50
presents noise levels measured near both small (the lower curve)
and large units.

     Unitary Split System Units are usually found in small build-
ings.  They are almost identical in function to rooftop units,  but
they are located on occupied floors in the building.  Thus, a
remote heat exchanger (either a condenser or cooling tower) must
t>e provided to reject waste heat when the units are cooling.  The
refrigerant compressor may be located remote from the unit together
with the condenser.

     Fan Coil Units are rather like miniature central station air-
conditioners in that they draw in fresh air and rely on outside
sources for hot water, cold water, or steam for their heating and
cooling coils.  They are small units, usually enclosed within a
cabinet and placed under or near windows.  Some units,  rather than
relyin6 on hot water, use electric heating coils.  Typical noise
levels for fan coil units are presented in Pig. A.51.

     Induction Units are similar in appearance and location to fan
coil units but receive air from a central station unit at a rather
high pressure, 1 to 4-in, static pressure, as compared to less
than 1-in. operating static pressure for unit ventilators.  This
                               A-31

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air is used to induce circulation of the room air.   Such units
are also provided with heating and cooling coils to temper the
air which they receive from the central supply.   A  range of
noise levels for typical induction units are shown  in Pig. A-52.

     Humidifiers,  Dehumidifierst  Heaters and Furnaces,  although
grouped under the heading of air conditioners, have only one
function:  to increase or decrease humidity, or to  heat.
      Humidifiers  are of two general types:   1)  those that add
      steam to the air,  and 2) those that blow the  air through
      or over moist surfaces to add water to the air.   Both
      types can be built into ductwork or can stand alone to
      serve a particular space.  The steam type  consists of a
      steam nozzle, a control valve, and possibly a fan.  The
      moist surface type consists of a fan (if not  located in
      ductwork),  a water pump, and a moving porous  belt or disk
      which passes through the water and then through the moving
      air.
      Dehumidifiers3  if  required, may be located in the ductwork
      where air flow is  provided  by the system fan.   The primary
      element  is  a cooling coil which condenses  moisture out of
      the passing  air.   In such an installation, a  heating coil
      may be provided to temper the excessively  cooled air that
      leaves the  cooling coil.   A self-contained unit will include
      a fan but usually  not a heating coil.
      Unit  Heaters consist of a remote fan and heating coil,
      which may be either electric or mechanical, and receive
      hot water or steam from an  external source.  Such units
      are often used in  little-occupied spaces such as mechanical
      equipment rooms, storage spaces, garages,  stairways, etc.
                              A-32

-------
      Warm Air Furnaces burn gaseous or oil fuel and use  an
      integral air-to-air heat exchanger to heat the air.  They
      usually have two built-in-fans, one to circulate  the air,
      the other to provide air for combustion.   They are  often
      used in small buildings which do not have access  to large
      quantities of hot water or steam.

A.3.5  Boilers
     For supplying warm air to a building, most air conditioning
systems use hot water or steam supplied by a boiler that  may be
located either nearby or remote from the building.   (In total
energy systems, waste heat from the engines may be  captured  to
heat water in place of or in addition to a boiler.)  Boilers
heat water or generate steam by burning a fuel and  passing the
water through or around the fire in a gas-to-liquid heat  exchanger.
There are two principal types of boilers:  water tube and fire
tube.  In the water tube boiler the-tubes are filled with water
and pass through the fire.  In the fire tube boiler, the boiler
is filled with water and combustion takes place in tubes that
pass through the water.  Steam boilers are usually  of the water
tube type, while hot water boilers may be either type.   Figure A-53
shows a range of noise levels typical of boiler operations;  fire
tube boilers are represented by the upper part of this range and
water tube boilers by the lower parts.  Gas-fired burners in
boilers are much quieter than oil-fired burners.

A.3.6  Refrigeration machines or chillers
     Refrigeration machines or chillers use various methods to
remove heat from water supplied to cooling coils (the "chilled
water") and transfer that heat to other water for  eventual
-rejection.
                              A-33

-------
      Absorption/Cycle Machines use heat energy and a salt solu-
 tion to transfer heat from the chilled water system to the reject
 heat system.   The machine is composed of tanks, condensers,  evapo-
 rators, heat  exchangers, pumps,  and controls.   On a per ton
 capacity basis, they are larger  than vapor compression cycle
 machines.   Figure A-5^ presents  noise levels typical of these
 machines for  building use.

      Vapor  Compression Cycle Machines,  which are  commonly called
 chillers, use  a compressor  to compress  the refrigerant;  the  re-
 sulting hot compressed gas  passes  through  a condenser  where  it
 is  cooled and  changed to a  liquid.   The  refrigerant  is  then  allowed
 to  expand,  further  cooling  it.   The  "chilled water"  is  then  passed
 through a heat  exchanger with the  cooled gas and  is  cooled.   The
 resulting heated  refrigerant  is  again compressed  and the  cycle
 repeated.   Chillers  use  various  types of compressors:   the posi-
 tive displacement  (piston and rotary  screw)  and the  centrifugal
 types;  noise levels  representative of these  types  are  presented
 in  Figs. A-55,  A-56,  and  A-57 respectively.

     Small Hermetic Refrigerant Compressors  are used in small
 airconditioners in conjunction with integral or remote air-cooled
 condensers.   These units  function exactly  the same as the com-
 pressors in vapor compression  cycle machines except  that  the
 refrigerant is  cooled  in  an air-cooled condenser rather than by
 a reject-heat  water-circuit condenser.

A.3.7  Heat  rejectors
     In most refrigeration machines, rejected heat is transferred
to  water, which may be used once, e.g.,  river water, or repeatedly,
in  which case  it must be cooled for re-use.  Cooling towers,
spray ponds, and air-cooled condensers are used to cool the water.

-------
     Cooling Towers receive large volumes of warm (typically 85°
to 75°F) water and cool it a few degrees.  In the process,  the
incoming warm water is sprayed onto the cooling tower "fill,"
a stack of wood, plastic planks or sheets, or ceramic blocks
which have a large surface area.  Typically, a fan is used  to
force air through the fill, cooling the water by evaporation.
The air is expelled in a saturated or near-saturated condition
and is usually a few degrees warmer.  Noise is generated by the
fan and by the water falling into the basin.  Centrifugal cooling
towers (using centrifugal fans) are quieter than propeller-fan
towers.  Figure A-58 presents a range of noise levels typical
for both centrifugal and propeller towers.

     Condensers of the liquid-cooled type are used in all large
refrigeration machines; smaller machines use directly air-cooled
condensers.  In a condenser, the entering gaseous refrigerant
is cooled as it passes through the gas-to-air exchanger, where
the gas condenses to its liquid form, and the resulting liquid
is returned to the refrigeration machine.  A fan is frequently
used to force air flow through the heat exchanger.  Figure A-59
presents a range of noise levels representative of air-cooled
condenser noise.

/\.3.8  Conveyance systems
     In multistory buildings, it is necessary to transport large
Cumbers of people quickly.  It is also desirable to transport
heavy objects from one floor to another, and in hotels, hospitals,
and apartments, to transport trash and soiled laundry to their
respective collection areas from many locations in the buildings.
glevators, escalators, and pneumatic transport systems are
examples of the conveyance systems used in buildings.
                              A-35

-------
      Elevators consist of three major components:  the cab, hoist
 cables and counterweights, and the hoist motors or hydraulic lift
 piston.  The weight of the cab is partially balanced by the counter-
 weights which are lowered as the cab is raised.  The hoist motors
 are DC-powered, which is best suited to the frequent starting,
 acceleration, and stopping operations of elevators.  Supply cur-
 rent is generated by accompanying motor-generator sets (using
 standard AC motor drives) or large rectifiers.   The hoist  motors
 are located directly over the elevator shaft,  usually on the
 roof of a building,  or at various upper floor  levels.   Hydraulic
 power is  sometimes  used for  distances of under 60 ft.   A hydraulic
 pump provides the driving force.   Figure A-60  presents noise
 levels  typically  found in elevator machinery rooms.

      Escalator's are  comprised of  two  major  components:   the stairs
 with tracks  and the  drive motors.   The  motors  are usually  located
 beneath the  lowest  flight, the upper  flights being driven  by those
 below.

     Pneumatic Transport  Systems use  low-pressure  differentials
 exerted over  large or  small areas  to  move comparable  sized  loads.
 The  chief components are  a high-pressure fan, a  duct  system,
 loading and unloading  stations, and control devices.   In a  typical
 system, the fan is run at an  idle  speed  (say 1/2  full  speed  which
 requires only 1/8 of the  full-speed hp) until the  loading station
 signals for full-speed operation.  The load is then conveyed
 through the duct system to the desired unloading station.  At
 the unloading station, the passage of the load signals the blower
which then drops to idle  speed.
                              A-36

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A.3.9  Ballasts
     Fluorescent and mercury arc lights require higher voltage
power than the normal 115v line current.  Ballasts are essen-
tially small transformers which alter the voltage to suit this
need.  Ballasts are usually mounted rigidly to light sheet metal
panels in order to provide the required cooling area.  These
panels often serve as very effective radiators of sound] thus,
the noise levels may vary considerably.  Figure A-61 presents
measured data for one installation.  Noise levels in other in-
stallations with different ballasts and fixtures may be as much
as 10 dB quieter or noisier than the curve presented.
                               A-37

-------
 REFERENCES
 1.    Rathe, E.J., "Gerauschnessungen an Baumaschinen," Acustica
      23(3) 1970, pp.  1119-155.

 2.    "Sound Data from Nebraska Tests," Implement and Tractor
      April 7,  1971.

 3-    Noise:   Final  Report,  Committee on the Problem of Noise,
      Sir Alan  Wilson, Chairman,  Her Majesty's Stationery Office
      London,  July 1963.

 h.    Ls.Benz,  P.,  Cohen,  A.,  and  Pearson,  B. ,  "A Noise  and Hearing
      Survey  of Earth-Moving  Equipment  Operators," Amer.  Ind.
      hygiene J.,  March-April 1967.

 5-    Based  on  estimates,  including  those  appearing in  "A Study  of
      Noise-Induced Hearing-Damage Risk for Operators of  Farm and
      Construction Equipment, Southwest Research Institute for  the
      Society of Automobile Engineers," Technical Report, SAE
      Research  Project R-4, December 1969.

 6.    Robinson,  D.W.,  "The Concept of Noise Pollution Level,"
      National  Physics Laboratory Aero  Report  AC 38,  March 1969.
                                                               •
 7-    Schultz,  T.J., "Technical Background  for Noise  Abatement  in
      HUD's Operating  Programs,"  BBN Report No.  2005,  September
      -L J f O *

 8.    Dugdale,  D.S., "Discrete Frequency Noise from Free  Running
      Circular  Saws,"  J. Sound Vib.  10(2):296-304  (1969).

 9.    Beranek,  L.L., Noise Reduction, McGraw-Hill  Book  Company,
      New York  (I960).

 10.    Beranek,  L.L., Noise and Vibration Control,  McGraw-Hill Book
      Company, New York (1971).

11.   Miller, L.N., "Noise and Vibration Control  for  Mechanical
      and Electrical Equipment in Buildings,"  Bolt  Beranek and
     Newman Inc. TIR No.  73, February  1970.

12.   ASHRAE Guide and  Data Book-Systems (1970).
                               A-38

-------
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-------
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-------
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-------
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-------
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-------
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-------
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-------
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-------
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-------
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-------
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-------
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-------
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-------
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FIG.  A.56   TYPICAL SOUND  PRESSURE LEVELS FROM CHILLER
           WITH ROTARY-SCREW COMPRESSOR (MEASURED  AT
           3 FT)

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APPENDIX B - IMPACT CONSIDERATIONS

B.I  Interpretation of Impact Estimates
     Sections 3.2.2 and 3-3.2 of this report have provided
detailed breakdowns of the impact on people of exposure  to
a variety of noise sources.  This section of the report  is
intended to permit the reader to gain an appreciation for
the significance of these estimates.  It therefore consists
primarily of caveats.
     First, it must be stressed that both the physical
levels of the noise sources and the levels at which effects
on people are specified are, at best, imperfect estimates.
Every attempt has been made to obtain unbiased and statisti-
cally sufficient estimates.  Nonetheless, the actual levels
mentioned in the text cannot be regarded as exact.  Vari-
ability is  inherent not only in the measurement process,
but also  in the noise sources, the propagation paths by
which their sounds are transmitted to people, and of course
in the responses of people.  Thus,  individual instances  of
extreme sensitivity to noise effects are  to be  expected, as
are cases of excessively  noisy and  quiet  sources.   In some
situations  the  total  amount  of variability  may  be so great
as to transform assessment  of noise  impact, a priori, into
an imponderable issue.   It  is important to  acknowledge  that
the impact  estimation of Sections  3.2.2 and 3«3-2 can per-
tain  only to  the  general, rather than the specific,  instance.
      It  must  also  be  understood  that research on the effects
of noise  on people has been conducted for the most  part under
controlled  and  simplified conditions.   The application  of
Knowledge gained  from such experimentation to heterogeneous
populations living in complex  environments necessarily  entails
                                 B-l

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  i i'alr amount of interpretation and approximation.  Disagreement
 among experts on matters of detail is probably unavoidable.
      Yet another important consideration to bear in mind when
 reading the sections on the impact of home appliance, building
 equipment, and construction noise on people is that these noises
 comprise only a fraction of most people's daily noise exposure.
 Since many noise effects are cumulative in nature, discussion of
 the impact of exposure to restricted classes of noise is both
 artificial and potentially misleading.   It is not safe to assume,
 for example,  that hearing damage is  not a substantial risk to
 the public at large merely because the  risk from construction
 noise exposure is negligible.
      In  short,  it has  been necessary  to make a large  number of
 assumptions  in preparing most  sections  of this report.   Assump-
 tions are  the coin  with  which  conclusions are purchased.   The
 reader must  understand the  assumptions  before he can  decide for
 himself whether  the conclusions  are worth the price.
      The final caution is  perhaps  the most  basic.   Stated simply,
 it is that no  attempt has been made in  this  report  to address
 the  crucial  issues  of social desirability and costs of  noise
 impacts.   Such issues were  purposely avoided  as  inappropriate
 and  far beyond the  scope of the  current report.  Value  judgments
 about how much noise exposure is tolerable must  inevitably  be
 made, however, if this report is to be  fully  useful.  Adminis-
 trative or legislative bodies must eventually  decide how  much
 hearing loss workers must suffer to maintain  industrial pro-
 ductivity;  how much annoyance,  stress, and task interference
 the public  must endure; how much sleep interference is too much;
and so forth.  The authors hope that this report will provide
the data and conclusions  essential for intelligent actions on
these issues.
                                B-2

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B.2  Discussion of Construction Data
     Table B-l tabulates  nonresid'ential  building  construction  in
1970 by the nature of metropolitan region  in which  eleven major
categories of buildings were constructed.   Construction  effort
in each building category is characterized both by  the number  of
sites and the total construction cost in each region.  The  average
cost of each type of building in each region is also presented in
Table B-l.  The cost estimates are necessary for  accurate  estima-
tion of the number of machine-hours of equipment  operation at
each site.  The wide variability of building costs  deserves
special note.  Office buildings in large,  high-density  central
cities cost an average of $1.9 million while the  same type of
building costs an average of only $.67 million in l,ow-density
central cities.
                                                 •
     The sources of the data in Table B-l include the following:
    • Columns 1 and 2:  Unpublished tabulation by U.S. Bureau  of
     the Census of all nonresidential building permits for 1970;
    • Columns 3,^,5 and 6:  Estimates based on population ratios,
     construction level ratios  (where known), and assumptions
     about probable unit costs; and
    • Column  7:  Constr-uation Review,,  except  for  lines 2, 55 and
     7, which  were estimated on the  basis of known  ratios  of
     large city to national construction  ratios.
     Two  categories  of nonresidential building are  recognized by
the Bureau of  the  Census but are  not discussed in  this  report.
One is  "residential  garages  and  carports",  of  which 150,885 were
authorized in  1970,  at an  average cost  of $1600.   Carport  con-
struction was  judged to  contribute negligibly  to construction
noise  problems.   The second category of buildings  recognized  by
                                 B-3

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TABLE B-l.   GEOGRAPHIC DISTRIBUTION OF MAJOR NONRESIDENTIAL  CONSTRUCTION
                       BY TYPE OF BUILDING (1970)

Type of Building
Office, Bank,
Professional
Hotel, Motel, etc.
Hospitals and
Institutions
Schools
Public Works Bldg.
Industrial
Parking Garage
Religious
Recreational
Store, Mercantile
Bldg.
Service, Repair
Station

Type of Building
Office, Bank,
Professional
Hotel, Motel, etc.
Hospitals and
Institutions
Schools
Public tforks Bldg.
Industrial
Parking Garage
Religious
Recreational
Store, Mercantile
Bldg.
Service, Repair
Station

Large High-Density
Central Cities
Bldq. Cost Avq. Cost
235 $438M $1863K
27 108 4015
123 326 2647
67 73 1091
58 48 822
362 92 253
82 33 398
81 21 255
43 17 402
533 84 159
341 12 44

Urban
Fringe
(Est.)
Bldg. Cost
3168 $600M
344 320
5590 468
687 197
689 196
6370 989
841 146
1826 185
1395 99
11425 998
3220 97

Large Low-Density
Central Cities
Bldq. Cost Avq. Cost
815
$559M $ 686K
56 76 1335
120 103 861
149 40 267
107 64 601
800 93 116
114 49 429
160 24 149
380 25 66
1649 205 124
553 13 23

Nonurbanized
Metropolitan
Area
(Est.)
Bldq. Cost
1424 $270M
154 143
265 210
309 88
310 88
2867 446
379 66
823 83
628 44
5148 449
1451 43
Outside
Metro-
pol i tan
Area
(Est.)
Bldq. Cost
2260 $456M
207 157
411 272
465 102
421 95
3706 391
500 72
970 71
998 51
7258 424
2050 42
Other Cen-
tral Cities
(Est.)
Bldq. Cost
1998 $378M
137 127
294 233
366 106
262 75
1961 306
279 48
392 40
932 65
4045 352
1355 41

il
National
Total
dg. Cost
9900 $2701M
929 931
1803 1611
2043 606
1847 566
16336 2316
2195 414
4252 423
4376 301
29058 2512
8970 247
                                 B-4

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  TABLE B-2.   GEOGRAPHIC DISTRIBUTION OF RES
            CONSTRUCTION BY TYPE OF BUILDING
                      Large High-Density
                       Central Cities*
IDENTIAL BUILDING
 (1970)
   Large Low-Density
     Central  Cities
Type of Building
Single-Unit
Two-Unit
Three- and Four-Unit
Five-Unit and Larger

Type of Building
Single-Unit
Two-Unit
Three- and Four-Unit
Five-Unit and Larger
Total
Const.
Bldg. Cost
5742 $ 86M
2044 46
177 9
745 532
Other
Central Ci
Total
Const.
Bldq. Cost
85776 $1478M
4776 92
" 3266 109
9496 1083
Avg.
Const.
Cost
$ 15. IK
22.7
51.2
716.0
ties
Avg.
Const.
Cost
$ 17. OK
19.3
33.4
190.0
Nonurbanized
Metropolitan Area
(Est.)
Type of Building
Single-Unit
Two-Unit
Three- and Four-Unit
Five-Unit and Larger

Type of Building
Single -Unit
Two-Unit
Three- and Four-Unit
Five-Unit and Larger
Total
Const.
Bldg. Cost
109018 $2171M
2800 63
1593 57
5166 957
National Total
Total
Const.
Bldg. Cost
624767 $11605
22231 482
11595 404
32465 6109
Avg .
Const.
Cost
$ 19. 9K
22.6
35.8
185.2





Total
Const .
Bldg. Cost
17213 $ 330M
1076 32
277 13
3012 802
Avg .
Const .
Cost
$ 19. 2K
29.8
46.2
266.0
Urban Fringe
(Est.)
Total
Const .
Bldq. Cost
241800 $4820M
6190 140
3542 127
11470 2123
Outside
Metropolitan
Total
Const.
Bldg. Cost
165218 $2720M
5455 109
2720 90
33.21 612





Avg.
Const.
Cost
$ 19. 9K
22.6
35.8
185.2
Area
Avg.
Const.
Cost
$ 16. IK
20.0
33.1
184.7





*See Sec. 3.2.1.2, Table IX, for definitions of large high-density
 and large low-density central cities.
                               B-5

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the Census but not discussed in the current report  is  "all  other
nL.nresicIential buildings",  of which 259,814 were authorized at
m  average cost of $6,760.   The latter category of  construction
was considered too heterogeneous in nature to permit reasonable
estimation of the nature of construction noise at a "typical"

     Table B-2 presents data on the construction effort involved
in erecting residential buildings as a function of the type of
metropolitan region in which the construction occurs.   The data
of  Table B-2 were obtained from unpublished Bureau of the Census
tabulations and from the Census publication Construction Reports:
Housing Authorized by Building Permits and Public Contracts, 1970

B.3  Estimating the Extent of Public Works Construction Noise
     The public is exposed to construction noise not only from
operations of erecting buildings of various sorts, but also from
operations arising from public works construction.  Such opera-
tions include road, highway, street, and sidewalk construction
and maintenance, as well as sewerage, water works, and utilities
installation and maintenance.  The noise created by these con-
struction activities is frequently prolonged and intense.  Even
small repair jobs on water works create considerable noise as
sections of pavement are ripped up to gain access to buried pipes,
     Estimation of the amount of noise created  by such activities
required that a number of assumptions be made  about the distribu-
tion of construction noise  from public works  sites.  The most
important assumption was that federal and  state public works
activity could be neglected  for the  purposes  of this study  since
it  occurs primarily  in  rural  regions  of  low  population density.
Attention was therefore concentrated  on municipal public works
activities within SMSAs.
                                B-6

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     Although summary reports  contain ample  Information  on  federal
and state public works activities,  comparable  municipal  data  are
available only from individual municipalities.   We  have  been  able
to obtain fairly complete data on municipal  public  works construc-
tion and maintenance for two large, high-density cities:  the
central city, Boston, Massachusetts, and the adjacent  city  of
Cambridge.  We have used this  information,  together with the  figure
of ^2,000 miles for municipal  street construction throughout  the
country in 1969, published by  the Federal Highway Administration,
to estimate total sewerage and water works  activity (in terms of
miles of pipe and mains laid)  for the country.
     In carrying out these calculations, we assumed average values
of 1.0 miles each of water and of sewer main per mile of new
street.  We further assumed that on the average, water and sewer
main additions per year would be 2% and 1,5$ of existing footage,
respectively, as opposed to 7.5% for the annual increase in length
of municipal street systems.  This gave estimated country-wide
values of some 11,000 miles of water mains and  8,000 miles of
sewage mains.  These estimates are considered reasonable in that
they are about half as great as would be obtained if the respec-
tive annual U.S. expenditure for water works and sewer  construction
were allocated solely to the installation of mains.  Moreover, some
mains would be installed concurrently with street construction and,
as a consequence, not constitute separate sources of noise pollu-
tion.
     Inherent  in our approach to the  estimation of exposure  of the
population to  municipal  construction  noise is the assumption  that
the  locus of both municipal construction and  of population exposed
is the  street  system of  a municipality.  We have therefore focused
on the  numbers of inhabitants distributed in  permanent  residence
along  the streets of a municipality  as  an index of the  impact of
                                 B-7

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 street-associated  municipal  construction  noise.   In order to facili-
 tate  the  use  of  this  approach,  we  developed  a  correlation (see
 Fig.  B-l)  between  population density  and  the quantities, miles of
 street  per square  mile  and inhabitants per mile of street for
 several dozen cities, towns  and counties  in  Massachusetts and Penn-
 sylvania  for  which we had data  available.
      Using the above  correlation,  together with the amounts of
 municipal  public works  con^cruction estimated  earlier, we arrived
 at  the  impact  estimates presented  in  Table B-3.   The indicated
 expos ares  of  residents  along streets  where municipal public works
 construction  is  taking  place are 10 million  and 4.4 million indi-
 viduals, for  street and water works and sewer  construction,
 respectively, making a  total of 14.4  million individuals exposed
 to  public  works  construction noise.

 B.4   Propagation Loss Model  For  Building  Construction Sites In
     Metropolitan  Areas
     Two classes of people are  exposed to construction noise:  the
 stationary population which  inhabits  the region around the construc-
 tion site  (workers and residents) and the transient population which
 passes by  the site (drivers,  passengers, and pedestrians.)  Two
models were constructed to estimate the extent to which site noise
 is attenuated for  each class  of observers.

     Stationary Population
     The entire stationary population around a construction site
was assumed to be indoors with closed windows.   Acoustic propaga-
tion loss  was modeled by postulating a representative site geometry
and applying the formula

     H = 20 log 5- + 20  dB
                HO
                                B-8

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              TABLE B-3.
      Activity
Street, highway
Sewerage & Water
Population Density
(people/sq. mi.)
Area (sq. mi.)
Street Distribution
(miles of street/
sq. mi.)
Linear Distribution
of Population
(people/mile of
street)
     ANNUAL  EXPOSURE OF  PERSONS  IN METROPOLITAN AREAS TO
          MUNICIPAL  CONSTRUCTION NOISE
    LENGTH OF MUNICIPAL  CONSTRUCTION  (MILES)
                                                    Met.  Areas
   Large,         Large,                             Outside
High-Density    Low-Density      All Other     Urban     Urban
      Activity
Street, highway
Sewerage & Mater
Central Cities Central Ci







273
125
398
15,160
1,468
21
720
RSONS EXPOSED

Hi
Cen




Large
gh-Density
tral Cities
196
90
286
2,150
990
3,140
4,410
2,389
10.2
430
ties Central Cities
6,000
2,700
8,700
3,710
6,981
9.5
390
TO MUNICIPAL CONSTRUCTION NOISE

Large ,
Low-Dens
Central Ci
925
425
1,350

ity All Other
ties Central Cities
2,340
1,050
3,390
Fringes
11,800
5,065
16,865
3,380
14,707
8.9
380
(X10~3)

Urban
Fringes
M70
1,920
6,390
Fringes
21,700
9,850
31,550
• 125
179,276
1.35
93

Met. Areas
Outside
Urban
Fringes
i r ~> ",
£. , 'J il 'J
920
2,9^0
Total
41,923
18,730
60,653






Total
9,951
•'4 ,403
14,356
.'. About 14.5 million people exposed to municipal construction noise.

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where H = total propagation loss
      R = range from source to observer
     Ro = reference range at which site source level
          was measured (50 ft).
Twenty dB was added to account for the loss through building walls
with closed windows.  The resulting transmission loss contours are
shown in Figure 19 of the main text.

     Transient Population
     People passing by a construction site continuously vary their
distance from the site.  A model such as the above is not directly
applicable.  The peak noise level to which passersby are exposed,
however, can be computed from the propagation loss at the passerby's
closest point of approach (CPA) to the site.  This propagation loss
is computed from the formula
                                  R!
                       H = 20 log 5— + E"
                                  KO

where H = total propagation loss
     RI = range at CPA
     RO = reference range at which site source level
          was measured (50 ft)
     .H' = is a term included to account for baffling or
          obstructions between source and observer

In the case of pedestrians, we assume that RI = 100 feet and H'
is zero.  H is therefore 6 dB.  For drivers, we have assumed
RI = 100 feet and H" = 15 dB to account for attenuation caused
by the transmission loss of an automobile.  For this case,
H = 21 dB, which was rounded to 20 dB to emphasize that the
figure is only an estimate.
                                B-10

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                                                                      100

                                                                      0.1
                                                                   30OOO
                     C=PEOPLE/SQ MILE
FIG.B-1   LINEAR  AND  AREA  DISTRIBUTION OF  POPULATION IN MUNIC
                   (BASED  ON  MASSACHUSETTS AND PENNSYLVANIA DATA)

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            APPENDIX C - SOUND LEVEL  CONSIDERATIONS
        BY AMERICAN CONSTRUCTION  MACHINERY  MANUFACTURERS
                               by
                          H.T. Larmore
        Deputy Director for Technical  & Safety Services
        Construction Industry Manufacturers Association
                      Milwaukee,  Wisconsin
                          Presented at
    The American Industrial Hygiene Association Conference
                       Toronto, Ontario
                         May 24,  1971

     This presentation will attempt to place the problem of noise
into its proper perspective relative to construction and construc-
tion machines — both as a potential cause of hearing loss for
workers and as an air pollutant for the nearby community at con-
struction sites.

NOISE - THE PROBLEM STATED
     Unwanted sound — is not new to the construction industry.
Construction sites are noisy.  Likewise, it is not new to heavy
machines used in the construction of buildings, highways, sewer
and water systems, airports and the like.  Indeed, it has been a
criterion by which some machines have been operated.  A skilled
operator often relies upon the sound of his equipment for proper
operation.  Also, noise is often associated with power in the
purchase of machines.

     These philosophical concepts and the public demand for lower
construction costs do not  excuse construction machinery from being
noisy, but they have  contributed to the major emphasis by manu-
facturers over  the past decade to design for  greater productivity
                              C-l

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 rather than to  build  quieter  machines.   The  transitory  and  tem-
 porary nature of  construction has  also  allowed  a  lack of  concern
 for  noise.   While  any particular contract  is  underway,  the  work-
 ers  and neighbors  might  well  be annoyed by the  noise.   But  relief
 comes  when  the  job is completed and  the big  machines move on.
 Next job  site — there are new workers;  new neighbors.
     During the past  few decades,  the public  demand has been for
 more production with  less labor and  less cost.  This prompted the
 development  of  today's remarkable  machines with more power, auto-
 mation  and  speed than ever before.   But  machine "improvements"
 to effect this  demand generally tended  to increase noise  levels.
 Larger  engines  produced  more  noise both  internally and  from the
 exhaust.  More  automation was  accomplished through more use of
 hydraulic power which also is  a noise generator.  Larger  engines
 and more hydraulic  power increased the  heat which must  be dissi-
 pated  through larger  quantities of air  being  driven by  noisier
 fans through larger radiators.  Increased speed means increased
 vibration frequencies which tend to  concentrate in the  audible
 hearing range.

 THE CONCERN  FOR NOISE
     The concern for  noise, only recently voiced by the public
 and expressed now  in  actual or proposed  legislation at  all  levels
 of government would seem to have created a major shift  from the
 "productive Sixties"  to  the "silent  Seventies".  Fortunately,
 our industry is geared to respond to our customer requirements
 and,  hopefully,  to recognize  changing requirements soon enough
 to accommodate the necessary  lead times for research and develop-
ment, testing, tooling, manufacturing and distribution.   Noise
 abatement, although recognized by manufacturers of construction
                              C-2

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machines as a legitimate environmental concern,  has been and still
is difficult to define in precise engineering and machine require-
ments — how much — how fast — what costs and trade-offs are accept-
able — cost/effectiveness ratios — all tend to remain fuzzy with
even man/noise effects far from being accurately determined.
     The manufacturers of construction machines, without waiting
for all the answers, recognized in the late sixties the need for
the basic tools for all change and/or regulation — Measurement
Standards.  Without such tools, base lines cannot be established
or progress measured.
     Through the Construction Industry Manufacturers Association
(CIMA) — the necessary machinery and policies were established
some four years ago to recognize needs for Performance or Safety
Standards and to promote development of such Standards by na-
tionally recognized technical and Standards writing bodies.
Among these were the basic noise measurement Standards as vol-
untary guidelines for both industry and government authors.
These were accepted for development by the Society of  Automo-
tive Engineers (SAE).  They include for construction machines:
     1.  Noise measurement at operator station
     2.  Noise measurement at 50  foot radius
     3.  Construction job  site  noise measurement
     4.  Cumulative operator noise  exposure measurement  along
         with  standardized reporting methods
Substantial progress has been made  by SAE  with  completion and
publication of some  of  these Standards  expected in the near
future.
                                C-3

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     The measurement of noise levels either at the operator's
station or at a distance from the machine is no simple matter.
A machine can be subjected to many operational variables.
Engine at rated speed, acceleration, full power drawbar load,
power take-off load, hydraulic load, idling engine, idling trans-
mission, transport, addition of a cab, roll-over protective
structures, windows open — these are some of the variables which
affect noise levels.  For that reason, a uniform procedure for
noise measurement is most important.
     There are currently under consideration at least four
Federal Bills and twenty State Legislative Bills which can regu-
late noise on construction machinery.  Consequently, there is
a real need for uniformity not only in measurement methods but
in noise limit levels.  It can be appreciated that legislators
are concerned with protecting operators and others from hearing
damage and the nuisance of excessive noise.  However, a mass of
legislation and regulations which are nonuniform are more of a
liability than an asset in reducing noise levels on construction
machines.  Nonuniformity with little or no lead time for making
the changes is leading to stop-gap measures which have unpredict-
able durability and effectiveness, and which perhaps introduce
unwanted trade-offs and compromises through overheating, fire
hazards,  maintenance interference and reduced output.

WHAT ARE MANUFACTURERS DOING ABOUT NOISE?
     So — what are construction machinery manufacturers doing
individually and as an industry?

     Individually they are:
     1.   Evaluating the many noise sources peculiar to each
         machine.

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     2.   Developing operator enclosures  for current  products.
     3.   Developing procedures for customizing current  products
         off the production lines.
     4.   Developing quieter components and systems for  quieter
         machines in the future.

Through CIMA they are:
     1.   Seeking new and updated SAE Standards and Recommended
         Practices for operator and exterior noise levels.
     2.   Organizing a cooperative effort among government, noise
         specialists, contractors and machinery manufacturers to
         accumulate the great masses of actual on-the-job noise
         data required by industrial hygienists in their evalua-
         tion of the man/noise effects in the construction envi-
         ronment .
     3.  Creating information on  construction machine noise for
         use by regulatory bodies, consumers, and information
         media.
     *J.  Investigating a means to express machinery noise sources
         in a uniform, usable and reliable manner.

THE COMPLEX ANSWERS
     These  individual and  collective  efforts  are  not simple nor
do results  come  easily  or  cheaply.   As  a  beginning, component noise
sources are rapidly  being  isolated  and  evaluated.   Oversimplifi-
cation of the problem frequently  leads  many to believe  that
engine exhaust  noises are  the  culprit and that larger mufflers
would turn  the  trick.   To  be  sure,  this is  part  of  the  problem.
However, noise  reduction of the  exhaust permits  other  machine
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noises to become dominant.  Larger mufflers also create a visi-
bility problem since they usually end up directly in front of
or behind the operator.
     There are several other noise sources which are the same
order of magnitude as exhaust noises, depending on the machine
and its configuration.

     These are:
     1.  Internal engine noises exclusive of the combustion
         itself. •
     2.  Engine  air inlet
     3.  Transmission and other gear noises.
     4.  Hydraulic system noises including the pump, tubes,
         valves, cylinders and hydraulic motors.
     5.  Air noise from the fan and radiator.
     6.  Various moving mechanical elements such as crawler
         tracks, or scraper elevators.

     It is very  likely that on a large machine today, each of
these noises is  individually in excess of 90 dB(A)  (decibels on
"A" rating scale).  In the case of two equal noise source levels,
the sum is about 3 dBA higher than either source alone.  For
four equal noise sources, the sum is about 6 dBA higher.  And
this in reverse  acts much the same way.  Suppose the total noise
of a machine is  100 dBA composed of four equal noise sources.
Let's say the exhaust, engine noises, gear and hydraulic noises
and fan noises are these four.  If by some magic the exhaust
and internal engine noises could be reduced to zero, the machine
would still have a noise level of 97 dBA.  So, this is the
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challenge to the engineers who are studying each noise  source
and striving for noise reduction of each component.

QUIETING CURRENT PRODUCTS
     For quieting current production machines,  some  manufacturers
are starting to use off-line, extra cost customizing.   This may
consist of one or more of the following:  An isolation  mounted
cab; larger muffler; sound deadening material around noisy com-
ponents; and vibration isolation of noise components.   These
methods are expensive and can have only minimal effect  on the
total problem.  Also, the sound absorbing insulation causes
some components to run hotter and can possibly absorb spilled
petroleum products.  This can be a fire hazard.  One would not
normally expect to replace such insulation during a machine's
expected useful lifetime but durability of such materials and
installation techniques are not broadly known.

FUTURE MACHINE QUIETNESS
     For future machines, larger capacity cooling fans with non-
resonant frequencies are being developed.  These would utilize
larger volumes of air at lower velocities, new radiator fin
designs and more efficient shrouds.
     Some gears must be changed from one form to another  and
perhaps made with more precision.  Much noise is generated from
variable gear  loadings and from gear idling.  Gears are designed
to  transmit a  given  power level at a required speed.  Variations
of  these will  set up vibrations which  cause  noise.  Here  again,
isolation and  insulation  seem  like possible  temporary solutions
but heat and  flexibility  can lead  to premature  failure and other
new problems.
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     Hydraulic pumps, transmission lines, valves, cylinders and
motors are all noise generators.  Oil flowing in a smooth, uni-
form path should be one of the quietest methods of generating,
transmitting and utilizing energy.  However, each component has
complicated restrictions which induce vibration.  If all of the
hydraulically performed functions were uniform and continuous,
the noise would be minimal.  But ease and flexibility of con-
trol are reasons for the many applications.  Noise reduction
programs for hydraulics are underway, but they will take time
for development, testing and adopting.
     Mechanical components such as the tracks of crawler tractors
are noisy but fortunately are of lower frequencies.  These types
of mechanisms are just not readily quieted and do not lend them-
selves to encapsulation treatment.  The long range, practical
solution for all these problems may well dictate future machines
of entirely new configurations.

NOISE STANDARDS AND REGULATIONS
     Because of the many noise sources which add up to a single
composite noise at an individual's ear, a unique but uniform
measurement is necessary.   For this purpose the SAE Standards
are a very practical solution.  The development of these Stan-
dards requires inputs from a broad spectrum of individuals with
various areas of interest.  One company cannot develop such
Standards nor can Just the machine manufacturers' industry.
But, through CIMA, the industry is promoting and lending its
support to the development of meaningful noise Standards by
independent Standards writing bodies which include experts
from manufacturers, government, public, users and labor.
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     As previously stated,  these  are  noise  measurement  and
reporting Standards being developed by  engineers  and  other
highly knowledgeable people in the construction field.   Ob-
viously, their efforts must be teamed with  practical  and effec-
tive noise limit Standards developed by the experts in  the
field of Industrial Hygiene.  Such limits should be in  keeping
with the peculiar type of exposure found in the construction
environment.  Only when these two tasks are completed can
effective and practical noise control programs and regulations
be designed and implemented.
     For Community Noise Control we visualize total construction
job site limits geared to the particular needs of  the  surround-
ing community.  This would  create  a natural demand for  quieter
machines yet still allow contractors and users to  utilize their
well demonstrated versatility and  ingenuity to get the  job done
in  compliance with realistic  job  site  noise limits even with
existing machines by using  new job layout  and  operational tech-
niques.
     For  control  of hearing damage risk we would urge  that  the
current Walsh-Healey  noise  exposure  tables might be  modified  for
construction  workers  to  more accurately reflect  their  unique
exposure  tQ intermittent,  variable intensity  noise and the  large
seasonable  fluctuations  in noise dosages.   These factors  are
covered in  some detail in a CIMA sponsored study published  by
SAE,  December 1969,  as Technical Report - SAE Research Project
R-4 and titled "A Study  of Noise Induced Hearing Damage Risk,
 for Operators of Farm and Construction Equipment".  This report
 is available from the Society of Automotive Engineers, Inc.,
 Two Pennsylvania Plaza,  New York, New York.
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     In summary, we have attempted to briefly review the back-
ground of construction machinery and the relatively recent public
concern for noise.
     We have outlined the complex and sophisticated industry
problems involved and our concern that the public may be moving
from apathy to overkill in one easy lesson.
     We have indicated an industry recognition of the responsi-
bility to help shape noise abatement legislation and regulation
into reasonable and responsible instruments; also, our past
and continuing active participation, through CIMA, to effectively
utilize our industry expertise in major and necessary Standards
activities.
     We spoke of the industry efforts, both from individual manu-
facturers and collectively through CIMA to create quieter ma-
chines except as a stop gap, high cost measure.
     We outlined the need for new noise limit criteria designed
in consideration of the unique types of noise exposure and
dosage for construction workers.
     It is obvious that construction machine designers and indus-
trial hygienists in both the government and private sectors are
operating at the threshold of the art relative to noise.  We
believe there is real and urgent need for a combining of these
two groups into a teamwork effort.  Through such a combined
grouping of expertise can come the tools and procedures to
effectively reach our common noise abatement objectives — and
to do so with full consideration of the total needs of our
society and at costs and compromises satisfactory to the public.
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APPENDIX D -  NOISE CONTROL:  REGULATION AND STANDARDS

D.I   Introduction

      Control of the noise produced by construction activity,
building equipment, and home appliances cannot be expected to
precede in an orderly fashion without supporting guidance in
the form of noise criteria, noise standards, and noise limits.
This section of the report presents information on the status
of currently available guidance for noise control.  Trends in
development of criteria, standards, and limits are discussed.
Where possible, future requirements for noise contro"1  guidance
are anticipated.
      A fundamental distinction must be made among the three
basic forms of guidance necessary for systematic noise control.
Noise criteria are defined as statements of the effects produced
by various levels of noise exposure.  Criteria are based on the
effects of noise on people, as discussed in Section 3.1 of
this report.  Noise standards describe the properties of
noise environments that are considered desirable.  Standards are
usually presented as long-term goals that a regulatory program
may be designed to attain.  Noise limits are in effect regulatory
documents intended to limit public exposure to individual noise
sources.   The limits entail not only a knowledge of the existing
noise environment, but also technological and economic constraints
on noise abatement.  It is intended by writers of noise limits
that the noise environment should approach the goals of noise
standards in a systematic fashion.
      The next section will discuss the elements involved in the
development and support of regulatory noise limits for construction
equipment; the third section of this appendix will discuss those
elements appropriate to building equipment and appliances.
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 D.2    Construction Equipment

      The body of this report has included discussion of criteria
 in the estimation and evaluation of the impact of construction
 equipment noise.  The criteria appropriate to construction equip-
 ment noise are not unique to such noise sources, of course. The
 selection of standards for noise exposure must take into account
 the characteristics of the combined impact of the many noise sources
 that pollute our environment, and most importantly, must be keyed
 to the business and recreational activities and situations in society
 that are to be protected from noise.  Thus, the development of a
 set of standards for the protection of human activity from noise
 pollution is beyond the scope of the present project and report;
 indeed, the ultimate selection will be based on further legislation
 incorporating decisions of national policy.   It is our intention
 here to describe the relationship between the various elements in
 an environmental regulatory scheme, and to identify their present
 state of development by scientific and engineering groups, and by
State and local governments.
      The third of these elements is the noise limit itself, which
provides quantitative restriction of noise emissions through incor-
poration in legally enforceable rules, regulations, and laws.
Quantitative limits must be directed at an identifiable legal entity
 (such as manufacturer, vendor or user), and must be accompanied by
specific test and measurement procedures.  Although no nationwide
noise regulations for construction or other powered outdoor equip-
ment now exist, several states are considering such noise limits, and
a number of larger cities have recently enacted or proposed limits
for construction equipment.
      The next section of this Appendix will review the recent
regulatory activities at the State and local levels that apply.
Since procedures for construction equipment noise measurement are
so important to the successful implementation of source limitations,
the last section will discuss these in more detail.
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      State and Local Regulations
      In the last two years,  considerable  activity has taken place
at the State and local level  with  regard to  reducing the noise of
outdoor construction, maintenance, and repair  activities.
      Both the State of Illinois and the State of Hawaii enacted
statutes in 1970 which grant  broad regulatory  powers over  noise to
specific state agencies.  At  this  time neither the  Illinois  Pollu-
tion Control Board nor the Hawaii  Dept. of Health have  adopted  any
rules or regulations to control construction noise.  The  Illinois
Institute for Environmental Quality has initiated a study  of noise
sources (including construction and other  outdoor powered equip-
ment) that could be covered by State regulations, and  proposed
limits for such equipment are being studied.
      In the State of California, a report to the 1971 Legislature
on the Subject of Noise was prepared by the State Dept. of Public
Health.   This report includes in its recommendations the establish-
ment of noise emission  standards  for all noise-producing objects
now in use as well as to be admitted in the future to California.
The construction noise  sources  identified in  the report include
all diesel-engine powered equipment,  such as  generators, compressors,
off-highway trucks,  bulldozers, loaders,  scrapers, power shovels and
other excavating equipment, as  well  as piledrivers, riveting machines,
Jack hammers,  elevators,  cement mixers, hammers, power saws, drills,
and nailers.    Other State legislatures have  or  will consider a
variety of proposed  construction  noise bills; a  bill submitted to
the New York  State  Legislature  in 1968 would  have  limited construc-
tion  noise as  measured  at the  nearest  multiple dwelling.
       Because  construction-equipment noise  is especially  severe
in urban  areas, limits  have  been  proposed or  adopted  in  several
larger cities.   New York City  has proposed coverage of construction
sites  by  permit, and limits  for air-compressor and paving-breaker
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 equipment in a new noise code; public hearings are scheduled to
 begin in the City Council Committee on Environmental Protection
 on 9 September 1971.  The City of Boston Air Pollution Control
 Commission has recently completed a study of community noise and,
 as part of its plan for noise control, will begin hearings
 27 September 1971 on proposed regulations which include limita-
 tions on noise of both construction/outdoor powered equipment
 and on the operation of a construction site.  The latter limits,
 in brief, apply at any nearby area open to the public except
 public' ways, or at a 1000-ft radius from the site, whichever
 is nearer.
     The City of Chicago adopted a comprehensive noise ordinance,
 effective 1 July 1971.  Section 17-4.8 provides that "No person
 shall sell or lease,...any powered equipment or powered hand
 tool that produces a maximum noise level exceeding the following
 noise limits at a distance of 50 ft, under test procedures es-
 tablished by...this chapter." and there follows a table of limits
 in dB(A) for four categories of equipment.  Two categories "Con-
 struction and Industrial Machinery" (#1) and "Commercial Service
Machinery" (#3) cover the bulk of construction equipment.
     "Construction and Industrial Machinery" includes powered
outdoor equipment, mobile or stationary, associated with con-
 struction sites or industrial operations.  Such equipment
includes crawler-tractors,  dozers, rotary drills, and augers,
 loaders, power shovels, cranes, derricks, motor graders,
paving machines,  off-highway trucks, ditchers, trenchers,
 compactors,  scrapers,  wagons, compressors, pavement breakers,
pneumatic-powered equipment, etc.  Specifically excluded are
pile drivers.

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     "Commercial Service Machinery"  includes  powered equipment
of 20 hp or less intended for infrequent  service  in residential
areas, typically requiring commercial or  skilled  operators.
Such equipment includes chain saws,  light pavement  breakers,
log chippers,  powered hand tools,  etc.
     The limits that apply to these  categories are  keyed to  the
date of manufacture of the equipment and  provide  a  timetable for
noise reduction as follows:

                        Construction and          Commercial
Manufactured after    Industrial Machinery    Service Machinery
   1 Jan. 1972              9^ dB(A)              88 dB(A)
   1 Jan. 1973              88 dB(A)              84 dB(A)
   1 Jan. 1975              86 dB(A)
   1 Jan. 1978
   1 Jan. 1980              80 dB(A)              80 dB(A)

     The application of the limits to equipment for  lease is most
appropriate in the case of construction machinery;  such equipment
is usually leased rather than sold.  Since the limits only apply
to equipment manufactured  after 1 January 1972, it  is too early
to look  for compiled results, but several contractors in the
Chicago  area are now'asking for "quieted" equipment  that will
meet  these limits, and  intend to use such equipment, insofar as
possible, to reduce or  eliminate community noise complaints.
This  provides very desirable pressure in the  market  place for
such  "quiet" equipment,  encouraging manufacturers  to offer  noise
control  packages  on their  construction equipment before  the re-
quired date.
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     Measurement Procedures
     Since quantitative limits must be applied to the noise
source, most test codes and recommended practices for measure-
ment apply to the operation of an individual item of construction
equipment.  The following noise measurement procedures are of
this form:
SAE* Standard J952a Sound Levels for Engine Powered Equipment
Scope:   For engine powered equipment including mobile construction
        and industrial machinery, but not covering machinery
        designed for operation on highways, or within factories
        and building areas.
Test Type:  Outdoor free-field measurement on level ground.  Mea-
            surement distance 50 ft.  Equipment operation at speed
            and load producing maximum sound level.
Data:   A-weighted sound level.

City of Chicago Environmental Control Ordinance, Article IV
Test Procedures for Noise Emitted by Engine-Powered Equipment
and Powered Hand Tools
Scope:   For engine-powered equipment, including construction and
        industrial machinery (not including pile drivers) agri-
        cultural tractors and equipment, powered commercial
        equipment of 20 hp or less, and powered equipment for
        use in residential areas.
*Society of Automotive Engineers, Inc., NYC, N.Y.  10001
"''Sec.  17-4.26 and corresponding section of DEC Code of Recommended
 Practice.   Chicago Department of Environmental Control, Chicago,
 111.   60610.
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Test Type:   Outdoor free-field measurement on level surface.
            Measurement distance 50 ft.   Both stationary  test
            and acceleration test (for rubber-tired mobile
            equipment) at load and speed producing maximum
            sound level.  Pneumatic equipment operated as
            specified in CAGI-PNEUROP Test Code.
Data:  A-weighted sound level.

ANSI* SI.19/193 (Proposed) Test-Site Measurement of Noise Emitted
                by Engine Powered Equipment
Scope:  For determining maximum noise emitted by construction
        and industrial machinery, transportation and recreation
        vehicles, and other engine-powered equipment.
Test Type:   Outdoor free-field on reflecting ground.  Measurement
            distance 15 meters (50 ft).  Moving and stationary
            tests for construction equipment (Sec. 4.*J).
Data:  A-weighted sound level

CAGI-PNEUPOP^ Test Code for the Measurement of Sound from
              Pneumatic Equipment
Scope:  Applies to compressors, percussive and nonpercussive
        pneumatic equipment.  Specifies procedures and operating
        conditions, not always including process noise.
*American National Standards Institute, NYC, N.Y.  10018
^Compressed Air and Gas Institute, NYC, N.Y.  10017
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Test Type:  Indoor or outdoor, measurements in direct field at
            five positions at 1 meter from equipment.  Secondary
            measurement at 7 meters distance.  Non-percussive
            tools measured running free and with "quiet" work
            process.
Data:  A-weighted and Octave-band sound pressure levels for
       each measurement point.

     The procedures adopted by the City of Chicago are based on
the SAE J952 standard and the revisions now under consideration
by the SAE Agricultural and Construction Machinery Sound Level
Subcommittee.   Substantially the same measurement procedures
have been proposed by the City of Boston Air Pollution Control
Commission in their Test Procedure for Measurement of Noise from
Pouered Devices.
     While SAE J952a contained specific noise limits, there are
being separated in a later revision now under consideration,
and the test procedure will appear separately.  This procedure
recommends an additional 2 dB tolerance for such noise measure-
ments; this provision has been deliberately omitted in both the
Chicago and Boston test procedures, and left to administrative
decision.  This is more appropriate, and not unlike the enforce-
ment measurement procedures for vehicular speed limits.
     Another approach to construction equipment noise measure-
ment is to apply the measurement to the combined operators of
all construction equipment at a single test site.  At the
request of CIMA (Construction Industry Manufacturers' Association)
the SAE is developing such a test procedure.
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SAE Recommended Practice (Proposed)  Construction Site Sound
Level Measurements
Scope:  For sites where construction machinery is operated.
        Measures noise radiated off-site.
Test Type:  Field measurement of radiated sound levels at four
            nearest inhabited locations to any centerpoint of
            construction activity.  If no inhabited locations
            closer than 1000 ft to a centerpoint, measurements
            made at 4 locations spaced 90° on 1000 ft radius
            circle.
Data:  A-weighted sound levels at each measurement point define
       "Construction Site Operational Sound Levels".  Provision
       for a record of  "Construction Site Baseline Sound Levels"
       allows limits to be expressed as  change  in ambient  as
       well as absolute terms.

     The  combined-operations measurement procedure is presently
being proposed for use  by the  City  of Boston,  and the City of
Chicago plans a test of the  latest  SAE draft  procedure as  part
of  a  feasibility  study  of noise limitations on construction sites
The Federal Highway Administration  Is considering this procedure
as  a  basis for regulation of noise  from  Federal-aid  highway
construction.
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 D.3  Noise Standards for Indoor and Outdoor Equipment for
     Home and Office Use
     The impetus for development of standards for measuring and
 rating the noise produced by many types of equipment has come
 from the manufacturers of noise sources.  For example, the manu-
 facturers of air conditioning and ventilation appliances are by
 far the most conscious of the impact of their equipment on the
 noise environment of the home and office.  Within the past
 decade at least ten different "standard" procedures have been
 formulated for measuring and rating the noise of various types
 of air conditioning and ventilating equipment.  The automotive
 and airframe industries have been similarly conscious of the
 noise impact of their equipment and sophisticated noise stan-
 dards exist for these sources.  By contrast, only one standard
 has appeared to deal with the noise of rotating electrical
 machinery; one to deal with gas turbines; one for gear noise;
 one standard of a general nature, produced by official American
 National Standards Institute (ANSI), intended to guide noise
 measurement of practically any piece of machinery; and a draft
 procedure is under consideration by ANSI to rate the noise of
 all engine-powered equipment.
     Such standards are of two types.  Measurement standards
 specify the manner in which meaningful and reliable acoustical
 data may be obtained.  Rating standards apply these acoustical
 data to produce ratings, usually single-numbered, that are
 supposed to correlate with subjective response to equipment
noise,  thus permitting at least rank-ordering of equipment noise
on a justifiable basis.
     Both sorts of standards are necessary and form the basis
for yet a third class of standards (applications standards) that
are used by architects,  consultants, building codes, noise
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ordinances and similar organizations.   Factors  which are  con-
sidered in developing application standards include the economic,
social, and political.  Applications standards  represent  an
equilibrium between the costs of reducing noise exposure  and the
feasible noise reduction made possible by acoustic technology.
     The following summaries indicate the general nature  of
existing U.S. noise measurement and rating standards for domes-
tic and office equipment.

ASHRAE* 36-62  Measurement of Sound Power Radiated from Heating,
               Refrigerating and Air-Conditioning Equipment
Scope:  For unitary, unducted equipment, large or small,  for
indoor or outdoor use.
Test Type:  Reverberation room, substitution method.
Data:  Total radiated sound power level in octave or 1/3-octave
bands.

ASHRAE* 36A-63  Method of Determining Sound Power Levels of Room
Air Conditioners and Other Ductless, Through-the-Wall  Equipment
Scope:  For room air conditioners, window or attic fans, and
other ductless wall- or ceiling-mounted equipment that radiate
sound directly both to the conditioned space and  the outdoors.
Test Type:  Reverberation room, substitution method  (2 rooms
needed).
Data:  Total sound power level radiated to indoors and outdoors,
separately, in 1/3-octave bands.
* American Society of Heating, Refrigerating and Air-Condition-
ing Engineers, Inc., 3^5 East 47th Street, New York, N.Y. 10017.
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ASHRAE 3SB-63  Method of Testing for Rating the Acoustic Perfor-
               mance of Air Control and Terminal Devices and
               Similar Equipment
Scope:  For air control and terminal devices normally mounted
in or connected to duct systems.
Test Type:  Reverberation room, substitution method.
Data:  Total sound power level radiated into the room served
by the device, in octave bands.
AMCA* 300-67  Test Code for Sound Rating Air Moving Devices
Scope:  For central station air conditioning and heating and
ventilating units, for centrifugal fans, axial and propeller
fans, power roof and wall ventilators, steam and hot water
unit heaters (but not unit ventilators, room fan-coil units,
room air induction units and air cooled refrigerant condensers).
Test Type:  Reverberation room, substitution method, based on
ASHRAE 36-62.
Data:  Total radiated sound power level, in octave bands
(including the sound radiated into the ducts, for ducted equip-
ment ).
AMCA* 301-65  Method of Publishing Sound Ratings for Air Moving
              Devices
Ratings for Centrifugal Pans, Axial and Propeller Fans, Power
Roof and Wall Ventilators, Steam and Hot Water Unit Heaters;
not yet suitable for central station A/C or H/V units.
     Ratings:  based on octave-band sound power levels, per
               AMCA 300-67:
                    For ducted devices, the eight octave-band
                    sound power levels;
*Air Moving and Conditioning Association, 205 West Touhy Ave.,
 Park Ridge, 111.  60068

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                     For unducted devices, the loudness in sones
                     at a reference distance of 5 ft, as calcu-
                     lated from the sound power level data.
AMCA 302  "Application of Sone Loudness Ratings for Nonduoted
         Air-Moving Devices"
Reference material covering applications of the loudness rating
in sones (examples, combinations of sources, prediction of sound
loudness indoors and outdoors, variation with fan speed.
AMCA 303  "Application of Sound Power Level Ratings for Ducted
         Air Moving Devices"
Reference material covering significance and accuracy of sound
power level ratings, particularly their relation to sound as heard
4NSI*S1.2 - 1962 "American Standard Method for the Physical
                 Measurement of Sound"
Scope:   For all devices, machines or apparatus.
        Several test procedures are described:
Test Type:  Free-field; free-field above reflecting plane; semi-
            reverberant field; or reverberation room.  The semi-
            reverberant field procedure is similar to that of
            ASHRAE 36-62.
Data:   Sound pressure levels at specific locations, or total
        sound power levels in octave bands (1/2-octave or 1/3-
        octave analysis optional); and directivity of the source.
  American National Standards Institute, 10 East 40th Street,
  New York, N.Y.  10016
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 IEEE* #85 "Airborne  Noise  Measurements  on  Rotating  Electric
           Machinery"
 Scope:   For rotating electrical  machinery  of  all  sizes
         Several  test procedures  are  described:
 Test Type:   Free field;  free  field above reflecting plane; semi-
             reverberant  field; or reverberation room.   (Similar
             to ANSI  Sl.2-1962, but more detailed.)
 Data:   Sound  levels or  sound pressure  levels in  frequency bands
         (octave,  1/3-octave,  or  "narrow")  at  specified  locations
         or total sound power  level,  overall or analyzed into
         frequency bands, and  directivity of source.
ANSI  SI.29/293 "Test-Site Measurement of Noise Emitted  by Engine-
               Powered Equipment" (Draft only,)
 Scope:   For residential  equipment (Section 4.5)  [Other sections
         deal with automobiles, motorcycles, construction and  in-
         dustrial machinery and recreational equipment]
 Test Type:   Sound levels measured on flat  test site with hard
             ground surface, free of  large  reflecting obstacles
             within 30 meters  of  equipment  under test.
Data:   A-weighted sound level measured at a  point  50 ft from
         center of equipment and  4 ft above ground,  for  noisiest
         direction and noisiest operating conditions.
ARI+  443-66  "Standard for Sound  Rating  of  Room Fan-Coil  Air-
             Conditioners "
Scope:   For room fan-coil  air conditioners.
*  Institute  of Electrical and Electronic  Engineers,  3^5  East  47th
   Street, New York, N.Y.  1001?
*  Air-Conditioning and Refrigeration  Instutute, 1815 North  Fort
   Meyer Drive, Arlington, Virginia    22209
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Test Type:  Reverberation room, substitution method, in accordance
            with ASHRAE 36-62
Data:  Octave-band sound power levels, computed from 1/3-octave
       band data corrected for presence of pure tones.
ARI 270-67 Standard for Sound Rating of Outdoor1 Unitary Equipment
Scope:  Outdoor sections of factory-made equipment, such as unitary
        air-conditioners or heat pumps.
Test Type:  Reverberation toom, substitution method, in accordance
            with ASHRAE 36-62 or ASHRAE 36A-63.
Data:   Sound power levels in 1/3-octave bands.
Rating: Single-number rating based on the 1/3-octave band sound
        power levels (corrected for the presence of pure tones),
        by a calculation like the ANSI Standard S3.4,  "Computation
        of Loudness of Noise".
ART 275-69 Standard for Application of Sound Rated Outdoor
           Unitary Equipment
Reference material (related to ARI 270-67) establishing a method
for predicting annoyance due to operation of outdoor unitary
equipment, and providing recommendations for application of such
equipment.
Calculation of annoyance level (ANL), taking into account distance,
reflections, location of equipment, shielding by barriers, loca-
tion of observer, multiple units, etc.
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 AH AM* SB-1  Room Air-Conditioner Sound Rating
 Scope:   Room air conditioners
o
 Test Type:   Reverberation room,  substitution method, in accordance
             with ASHRAE 36A-63
 Data:    Single number (or letter)  ratings based on the 1/3-octave
         band sound power levels  (corrected 'for the presence of
         pure tones),  by a calculation like the ANSI Standard S3.4
         "Computation  of Loudness of Noise";  the calculations are
         different for the indoor side and the outdoor side of the
         unit,  such that the two  sound ratings would be the same
         if  the sound  power levels  radiated indoors were all 15 dB
         less than the levels in  corresponding frequency bands
         radiated to the outdoors.   The outdoor calcuation is the
         same as that  of ARI 270-67.   The indoor sound rating
         (a  number) is converted  to a letter rating (11=A, 12=B,
         13=C,  etc.) for publication purposes.
 HVI+#1966-1  Sound Test- Procedure
 Scope:   For home ventilating equipment.
 Test Type:   Reverberation room,  substitution method, similar to
             ASHRAE 36-62
 Data:    Octave band sound power  levels,  calculated from 1/3-octave
         band sound pressure levels,  are  used to compute octave-band
         free-field sound pressure  levels at a reference 5-foot
         distance.
 Rating:  The  nominal free-field octave-band SPL's at 5 foot are
         used to calculate loudness in sones, a single number,
   T__., j ,__,_,, 	LL_    .--!--., —--, - L  - -  .._rv _i._r--                         "-*-'
 *  Association of Home Appliance Manufacturers, 20 North Wacker
   Drive, Chicago,  Illinois   60606
+  Home  Ventilating Institute
                               D-16

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         according to ANSI S3.4 - 1968, "Computation of Loudness
         of Noise."
ADC* Test Code 1062 Rl Equipment Test Code
Scope:  For air distribution and control devices (high pressure
        units).
Test Type:  Reverberation room, substitution method, in accordance
            with ASHRE 366-63 (except that the ASHRAE test for
            attenuation of terminal devices is not used).
Data:   Total sound power level radiated into room, in octave bands,
     In addition to these standards for measuring and rating noise
from various kinds of ventilation equipment, both the Home Venti-
lating Institute and the Air Conditioning and Refrigeration Insti-
tute have published directories of equipment, giving noise ratings
for each model tested (a large proportion of the manufactured
models); and both the Air Conditioning and Refrigeration Institute
and the Association of Home Appliance Manufacturers offer guidance
for the writers of noise ordinances dealing with their equipment
types, to indicate achievable goals and the necessary wording in
terms of existing standards, to make the model ordinances en-
forceable.
     At the present time, the existence of several different
measurement and rating standards in the ventilating/air-condition-
ing field is something of an embarrassment, since they are not
* Air Diffusion Council, 435 North Michigan Ave., Chicago, 111. 6o6ll
                               D-17

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mutually consistent nor even  compatible,  but  are competing for
general acceptance.  In an attempt  to  deal with this situation,
an ad_ hoc working group of ANSI  is  currently  trying to draft a
standard for both measurement and rating  of equipment noise that
exhibits the best features of the already existing standards and
that, it is hoped, will be found acceptable by the various organi-
zations that have pioneered in the  standardization effort in the
United States.  It is still too  early  to  predict whether this
action will be successful.
     In spite of the slightly chaotic  present situation, it is
clear that a great deal of careful  thinking has been done about
how to measure equipment noise in the  United  States; indeed, in
this area the U. S. is somewhat  in  advance of the European
practice.
                               ~J-O         ftU.S. GOVERNMENT MINTINO OMICS:197? 514-1SJ/2U 1-J

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