ENVIRONMENTAL PROTECTION AGENCY
REGION 10 NOISE PROGRAM
NOISE GUIDELINES FOR ENVIRONMENTAL IMPACT STATEMENTS*
The purpose of this text is to identify information which should bfe
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included in an EIS to accurately describe the environment and noise
impacts attributable to the proposed project. Unless a thorough study
is made which addresses all applicable noise problems, there can be no
completely valid assessment of the project's effects on the environment.
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The following information is recommended in order to evaluate
the noise impact of the proposed action and the alternatives:
a. The existing and anticipated land uses near the project
site or route that have a sensitivity to noise including the number of
persons living near the site or route. (Particularly facilities in which
speech or sleep occurs such as residences, motels, hotels, hospitals,
schools, as well as recreational areas such as parks, campgrounds, nature
preserves). What is the zoning and what does the comprehensive plan
anticipate as the land use for undeveloped areas? (This information is
needed in order to avoid allowing a noisy activity in an area planned for
residential or other noise sensitive use).
b. The existing noise levels adjacent to the project site or
route. Sites should be selected both for their proximity to the projected
noise source as well as for their noise sensitivity. Levels should be
given in dBA units (preferably Leq and Ldn) as well as the noise character-
istics at the identified test sites. Methodology for determing these levels
and qualifications of the investigator should be indicated.
c. The noise levels anticipated in these areas emanating from
a completed project. Levels in dBA should be documented for the same test
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sites at which existing levels were measured. (Peak noise levels should
be determined because of their importance for sleep interference). Methodology
(noise prediction model) for determing these levels should be indicated, as
well as experimental verification of the accuracy of the noise prediction
model.
d. The information used to determine the impact of the predicted
noise levels. This includes, but is not limited to, the following criteria:
(1) What increase is considered tolerable?
(2) What levels are considered reasonable for various
uses?
(3) Upon what basis is this information established (i.e.,
the Levels Document, sleep, speech and/or task interfer-
ence)? The reference for the selected information
should be cited.
(4) State and municipal standards or ordinances which
apply should be cited.
Tabular summaries which present the numbers of residences and other
noise sensitive areas which will realize changes in their present levels
should be compiled. These should describe quantitatively how many will be
receiving levels in excess of L10 70 dBA, and how many will experience increases
over the present ambient of 0-5 dBA (slight impact), 5-10 dBA (significant
impact) and over 10 dBA (very serious impact).
e. What noise abatement means will be utilized to reduce noise
from the completed project and noise generated during construction. A
description of the levels of expected attenuation should be included.
Abatement requirements will vary from project to project, but should consider
at least the following measures:
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(1) acoustic barriers, berms and fences
s
(2) retention of trees and other flora
(3) application of the newest quieting technology
and acoustic design
and during construction:
(1) the use and maintenance of properly operating
/'mufflers and quieting devices
(2) the use of the quietest available machinery and
equipment
(3) the use of electric equipment in preference to gas,
diesel or pneumatic machinery
(4) locating construction equipment as far from nearby
noise sensitive properties as possible
(5) shutting off idling equipment
(6) limitation of construction hours to coincide with
the normal workday period, e.g. 8:00am to 6:00pm
(7) scheduling the noisiest operations near the middle of
the day, and notifying nearby residents whenever
extremely noisy work will be occurring.
(8) the use of permanent or portable acoustic barriers
around point noise sources.
The effectiveness of abatement measures should be described and
demonstrated by the use of accepted noise prediction techniques. Plans
to monitor noise during construction and at the completed project should
be described.
f. What facilities will not be protected by the above abatement
measures and what impact might this lack of protection have?
(1) Has consideration been given to procuring the
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additional land as a buffer zone or compensating
for infringment of the use of the property?
(2) A cost benefit study of the trade off between noise
reduction and land costs should be made where
appropriate.
The EPA Levels Document
In March 1974, EPA published Information on Levels of Environmental
Noise Requisite to Protect Public Health and Welfare with an Adequate
Margin of Safety (Levels Document). Since the levels identified in this
document are based soley upon health and welfare considerations, care was
taken to use the words "identified levels" and avoid such words as "goals",
"standards", or "recommended levels". Nevertheless, they have been frequently
misinterpreted by others when referenced by EPA personnel in the conduct of
their review of other agency Environmental Impact Statements.
For residences with outside space, an outside environmental noise level
of Ldn = 55 was identified in the Levels Document as that level required to
protect against both hearing loss and activity interference with an adequate
margin of safety. This, despite disclaimers to the contrary, has been
erroneously interpreted as an implied standard. L
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for with the recognition that the time horizon for actual achievement in
individual cases will depend on a variety of other considerations. Until
more definitive guidelines are established for various types of projects,
EPA personnel will be guided by the general considerations in the attached
chart.
In the Levels Document, EPA also established the Lgq/Lcin methodology
as the uniform environmental noise descriptor recognizing that other des-
criptors may be appropriate for source emission controls of individual
products or for other purposes. EPA recommends that the environmental noise
impact analysis for this action employ the L^/L^p noise descriptor methodology
as the uniform environmental noise descriptor for Federal agency action.
*January 1975, revised November 24, 1980
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FOR RESIDENTIAL, HOSPITAL AND EDUCATIONAL
ACTIVITY
Environmental Noise Level'
Associated with an Action
(<;xl t:i mi unvii onmc-iil)
Qualitative Considerations Applicable to
Individual Actions
Levels have unacceptable public health and
welfare impacts
Significant adverse noise impacts exist:
allowable only in unusual cases where lower
levels are clearly demonstrated not to be
Adverse noise impacts exist: lowest noise
level possible should be strived for.
Levels are generally acceptable: no noise
impact is generally associated with these
levels.
'Some structures do not contain relevant exterior activity space and therefore, in these cases, special
determination of the acceptability of the interior environment should be made.
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