-------
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.
-------
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
-------
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
-------
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
-------
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.
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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.
-------
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
-------
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
-------
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) .
-------
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
-------
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
-------
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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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
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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.
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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.
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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.
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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
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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
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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.
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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.
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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
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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
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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.
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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.
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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,
170
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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,
171
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NOISE REDUCTION
FIG. 27. COST OF NOISE CONTROL VS NOISE REDUCTION
172
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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
173
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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
-------
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
176
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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
177
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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
178
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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:
179
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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
180
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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-------
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
Scraper
Shovel
Truck
[81]
[85]
[85]
[82]
L76]
[88]
[83]
[80]
L78]
[85]
[88]
[79]
[89]
[101]
[85J
[76]
[98]
[74]
[78]
[88]
[82]
[91]
S-
(0
0)
r
O
.04
.04
.4
.05
.16
.14
.16(2)
ro
o
X
UJ
1.0
.16
.16
.4
.1
.16
.4
.04
.2
.16(2)
-o
c
3
O
u_
.4
.4
.4
.04
.04
.04
1.0(2)
.04(2)
0
QJ
S-
LlJ
.4
.16
.04
.08 .
.04
.1(3)
.4
.1(2)
£
c
I
U.
.4
.04
.16
.08
.02
.04
.04
.02
.04
.04
.22
.04(2)
.05
.1
.08
.06
.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-7
-------
TABLE A-2d. USAGE FACTORS OF EQUIPMENT
IN PUBLIC WORKS CONSTRUCTION*
Equipment"1"
Construction Phase
c
o
to
c
o
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
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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
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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
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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
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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
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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
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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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100
-
UJ
40
RATED POWER: 45 TO 770 HP
ENGINE SPEED: 1100 TO 2700 RPM
INCLUDES FRONT LOADERS, BACKHOES,
CRANES, BULLDOZERS, CONCRETE MIXERS,
GRADERS, PAVERS
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FIG. A.I ENVELOPE OF SOUND PRESSURE LEVELS FROM 23 DIESEL-
POWERF.D ITEMS OR CONSTRUCTION EQUIPMENT
(MEASURED AT 50 FT)
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100 160 250 400 630 1000 1600 2500 4000 6300 10000
125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.2 SOUND PRESSURE LEVELS FROM TWO BULLDOZERS UNDER
VARIOUS CONDITIONS (MEASURED AT 50 FT)
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FIG. A.3 SOUND PRESSURE LEVELS FROM TWO GASOLINE-ENGINE POWERED
ITEMS OR CONSTRUCTION EQUIPMENT (MEASURED AT 50 FT)
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50 80 125 200 315 500 800 1250 2000 3150 5000 8000
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FIG. A.4 SOUND PRESSURE LEVELS
(MEASURED AT 50 FT)
FROM TWO AIR COMPRESSORS
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GENERATORS, GASOLINE ENGINE POWERED:
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- G2- 10 KW, 20 HP ENGINE
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FOR ARC WELDING
PUMPS:
PI -STRIPPING PUMP, 7 HP
-DIRECT DISPLACEMENT PUMP
1 HP
1
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jG A.5 SOUND PRESSURE LEVELS FROM GENERATORS AND PUMPS
(MEASURED AT 50 FT)
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A.6 SOUND PRESSURE LEVELS FROM VIBRATOR AND SAWS
(MEASURED AT 50 FT)
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PNEUMATIC WRENCH
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50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
IG A.7 SOUND PRESSURE LEVELS FROM VARIOUS PNEUMATIC TOOLS
(MEASURED AT 50 FT)
-------
120
STEAM POWERED
DIESEL (PEAKS)
SONIC
50
31.5 63 125 250 500 1000 2000 4000 8000
OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A. 8 PEAK SOUND PRESSURE LEVELS FROM PILE DRIVERS, DRIVING
14-IN. DIAMETER PIPE PILES (MEASURED AT 50 FT)
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50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.9 SOUND PRESSURE LEVELS
(MEASURED AT 3 FT)
FROM TWO CAN OPENERS
-------
10
63 100 160 250 400 630 1000 1600 2500 4000 6300 10000
80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.10 SOUND PRESSURE LEVELS FROM FIVE CLOTHES DRYERS
(MEASURED AT 3 FT)
-------
20
63 100 160 250 400 630 1000 1600 2500 4000 6300 10000
50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.11 SOUND PRESSURE LEVELS FROM FIVE CLOTHES WASHERS
DURING THE WASH CYCLE (MEASURED AT 3 FT)
-------
31.5
63 125 250 500 1000 2000 4000 8000
OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.12 SOUND PRESSURE LEVELS FROM FOUR CLOTHES WASHERS
DURING THE SPIN CYCLE (MEASURED AT 3 FT)
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50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.13 SOUND PRESSURE LEVELS
(MEASURED AT 3 FT)
FROM A DEHUMIDIFIER
A-51
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63 100 160 250 400 630 1000 1600 2500 4000 6300 10,000
50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.14 SOUND PRESSURE LEVELS FROM AN
TRIMMER (MEASURED AT 3 FT)
EDGER AND
A-52
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63 100 160 250 400 630 1000 1600 2500 4000 6300 10,000
50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.15 SOUND PRESSURE LEVELS OF THREE WINDOW
FANS (MEASURED AT 3 FT)
A-53
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10
fln100,oJ6CLrt250 40° 63° 1000 1600 2500 4000 6300 0,000
125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.16 SOUND PRESSURE LEVELS OF THREE FLOOR FANS
(MEASURED AT 3 FT)
-------
80
63 100 160 250 400 630 1000 1600 2500 4000 6300 10,000
50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.17 SOUND PRESSURE LEVELS FROM A STOVE HOOD
EXHAUST FAN 4 SPEEDS (MEASURED AT 3 FT)
A-'-1;
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63 100 160 250 400 630 1000 1600 2500 4000 6300 10,000
50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.18 SOUND PRESSURE LEVELS FROM A FOOD BLENDER
EIGHT DIFFERENT SPEEDS (MEASURED AT 3 FT)
-------
63 100 160 250 400 630 1000 1600 2500 4000 6300 10,000
50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.19 SOUND PRESSURE LEVELS FROM FIVE BLENDERS
AT MAXIMUM SPEED (MEASURED AT 3 FT)
-------
80
63 100 160 250 400 630 1000 1600 2500 4000 6300 10,000
50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.20 SOUND PRESSURE LEVELS
AT LOW AND HIGH SPEED
FROM FOUR FOOD MIXERS
(MEASURED AT 3 FT)
-------
63 100 160 250 400 630 1000 1600 2500 4000 6300 10,000
50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.21 SOUND PRESSURE LEVELS
(MEASURED AT 3 FT)
FROM TWO FREEZERS
A-59
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63 100 160 250 400 630 1000 1600 2500 4000 63OO 10,000
50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.22 SOUND PRESSURE LEVELS FROM THREE HAIR DRYERS
(MEASURED AT 3 FT)
A-60
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ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.23 SOUND PRESSURE LEVELS FOR A BELT SANDER
RUNNING FREE AND SANDING WOOD (MEASURED AT
3 FT)
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ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.24 SOUND PRESSURE LEVELS FROM THREE DRILLS
(MEASURED AT 3 FT)
A-62
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63 100 160 250 400 630 1000 1600 2500 4000 6300 10,000
50 80 125 200 315 5OO 8OO 1250 2OOO 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.25 SOUND PRESSURE LEVELS FROM TWO DRILL
PRESSES DRILLING THROUGH WOOD AND METAL
(MEASURED AT 3 FT)
A-63
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63 100 160 250 400 630 1000 1600 2500 4000 6300 10,000
50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.26 SOUND PRESSURE LEVELS FROM THREE GRINDERS
GRINDING METAL STOCK (MEASURED AT 3 FT)
-------
63 100 160 250 400 630 1000 1600 2500 4000 6300 10,000
50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.27 SOUND PRESSURE LEVELS FROM A ROUTER RUNNING
FREE AND WORKING WOOD (MEASURED AT 3 FT)
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50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.28 SOUND PRESSURE LEVELS FROM A SMALL METAL
LATHE RUNNING FREE AND CUTTING
(MEASURED AT 3 FT)
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50 80 125 200 315 500 800 1250 2000 3150 5000 800O
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.29 SOUND PRESSURE LEVELS FROM A SABRE SAW
RUNNING FREE AND CUTTING WOOD (MEASURED AT
3 FT)
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63 100 160 250 400 630 1000 1600 2500 4000 6300 10,000
50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.30 SOUND PRESSURE LEVELS FROM FOUR DIFFERENT
SAWS CUTTING WOOD (MEASURED AT 3 FT)
A-68
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63 100 160 250 400 630 10OO 1600 2500 4000 6300 10,000
50 80 125 200 315 5OO 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.31 SOUND PRESSURE LEVELS FROM A ROOM DEHUMIDIFIER
FOR THREE SETTINGS (MEASURED AT 3 FT)
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50 80 125 200 315 500 800 1250 2000 3150 5000 8000
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FIG. A.32 SOUND PRESSURE LEVELS FROM TWO ELECTRIC
KNIVES (MEASURED AT 3 FT)
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FIG. A.33 SOUND PRESSURE LEVELS
(MEASURED AT 3 FT)
FROM TWO REFRIGERATORS
A-71
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63 100 160 250 400 630 1000 1600 2500 4000 6300 10,000
50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.34 SOUND PRESSURE LEVELS
MACHINES (MEASURED AT
FROM TWO SEWING
3 FT)
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63 100 160 250 400 630 1000 1600 2500 4000 6300 10,000
50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.35 SOUND PRESSURE LEVELS FROM FOUR MEN
ELECTRIC SHAVERS (MEASURED AT 3 FT)
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3 100 160 250 400 630 1000 1600 2500 4000 6300 10,000
50 80 125 200 315 500 800 1250 2000 3150 5000 8000
ONE-THIRD OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.36 SOUND PRESSURE LEVELS FROM TWO WOMEN'S
ELECTRIC SHAVERS (MEASURED AT 3 FT)
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FIG. A.37 SOUND PRESSURE LEVELS FROM AN
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FIG. A.38 RANGE OF SOUND PRESSURE LEVELS FROM DIFFERENT
SIZES OF MOTORS (MEASURED AT 3 FT)
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FIG. A.39 RANGE OF SOUND PRESSURE LEVELS FROM INTERNAL
COMBUSTION ENGINES (MEASURED AT 3 FT)
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FIG. A.43 RANGE OF SOUND PRESSURE LEVELS FROM PUMPS
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FIG. A. 45
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FIG. A.47 RANGE OF SOUND PRESSURE LEVELS
GRILLS, REGISTERS, AND LOUVERS
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FIG. A.48 TYPICAL SOUND PRESSURE LEVELS FROM RECIPROCATING
AIR COMPRESSORS (MEASURED AT 3 FT)
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FIG. A.49 RANGE OF SOUND PRESSURE LEVELS FOR CENTRAL
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FIG. A.52 RANGE OF SOUND PRESSURE LEVELS FROM INDUCTION
UNITS (MEASURED AT 3 FT)
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FIG. A.53 RANGE OF SOUND PRESSURE LEVELS FROM BOILERS
(MEASURED AT 3 FT)
A-91
-------
iND SOUND PRESSURE LEVEL IN dB re 20/iN/m*
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OCTAVE BAND CENTER FREQUENCY IN Hz
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FIG. A.55 TYPICAL SOUND PRESSURE LEVELS FROM CHILLER
WITH RECIPROCATING COMPRESSOR (MEASURED AT
3 FT)
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.5 63 125 250 500 1000 2000 4000 8000
OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.56 TYPICAL SOUND PRESSURE LEVELS FROM CHILLER
WITH ROTARY-SCREW COMPRESSOR (MEASURED AT
3 FT)
-------
no
CM
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OCTAVE BAND CENTER FREQUENCY IN Hz
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FIG
A.57 RANGE OF SOUND PRESSURE LEVELS FROM CHILLER
WITH CENTRIFUGAL COMPRESSOR (MEASURED AT
3 FT)
A-95
-------
110
cvi
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31.5 63 125 250 500 1000 2000
OCTAVE BAND CENTER FREQUENCY IN Hz
4000
8000
FIG. A.58 RANGE OF SOUND PRESSURE LEVELS
TOWERS (MEASURED AT 3 FT)
FROM COOLING
A-9 6
-------
110
E 100
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63 125 250 500 1000 2000 4000 8000
OCTAVE BAND CENTER FREQUENCY IN Hz
FIG. A.59 RANGE OF SOUND PRESSURE LEVELS FROM AIR-COOLED
CONDENSERS (MEASURED AT 3 FT)
A-97
-------
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31.5 63 125 250 500 1000 2000 4000
OCTAVE BAND CENTER FREQUENCY IN Hz
8000
FIG. A.60 RANGE OF SOUND PRESSURE LEVELS FROM ELEVATOR
ROOM (MEASURED AT 3 FT)
A-9!
-------
31.5
125 250 5OO 1000 200O
OCTAVE BAND CENTER FREQUENCY IN Hz
4000 8000
FIG. A.61 SOUND PRESSURE LEVELS
(MEASURED AT 3 FT)
FROM BALLASTS
A-99
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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.
-------
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
-------
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)
-------
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
-------
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
-------
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
-------
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.
-------
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
C-5
-------
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
D-10
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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
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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
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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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