Introduction to Acoustics

1008 Part G Structural Acoustics and Noise
Part G 23.5
detailed in an FHWA policy document [23.177]. It is,
however, the responsibility of each State Department of
Transportation (SDoT) to determine the extent of noise
abatement measures and to balance costs and environmental
benefits in determining where noise barriers are
to be erected.
Industrial Noise Emissions. The policy situation with
regard to industrial noise immissions varies from stateto-state.
The Internet site maintained by the Noise
Pollution Clearing House [23.178] lists 12 states (with
links to the requirements) with regulations on noise. One
of the states not listed is the state of Maine – whose noise
requirements have been described as the most complex
in the United States [23.179]. These requirements show
evidence of being carefully written. Brooks [23.180,181]
has identified two other states, Illinois [23.182] and
Connecticut [23.183] as two other states with carefully
crafted environmental noise regulations.
The Maine text is in the Department of Environmental
Protection regulations 375.10, and is approximately
6000 words in length. The requirements are
written in terms of hourly A-weighed sound levels. Daytime
levels are between 7 a.m. and 7 p.m., and nighttime
levels are between 7 p.m. and 7 a.m. The key elements
are:
• In protected locations that are not predominantly
commercial, transportation, or industrial, 60 dB daytime
and 50 dB nighttime.
• In other areas, the required levels are 10 dB higher.
• Where pre-development levels are less than 45 dB in
the daytime and 35 dB at night, the required levels
are 5 dB lower.
• There are penalties for repetitive sounds and requirements
on blast noise.
• Maximum levels are specified for construction activities.
Local Noise Regulations and Policies. A large number
of cities and towns in the United States have ordinances
and building codes to deal with local noise issues. For
example, noise ordinances from cities and towns in 31
states have been posted on the Internet by the Noise
Pollution Clearing House [23.177]. A model noise ordinance
published by the EPA and dating from 1975
September has also been posted [23.184]. However,
there is no consistency in how local noise ordinances
are structured. Some use subjective noise exposure criteria,
while others use objective, quantitative criteria.
As described by Finegold and Brooks [23.185], an
American National Standards Institute (ANSI) working
group is currently developing a new ANSI standard
with an updated model community noise ordinance for
use by local jurisdictions to provide the needed guidance.
There is a strong preference for objective noise
standards as opposed to subjective standards. For example,
a requirement for the prohibition of excessive and
unreasonable noises without objective limits is difficult
to enforce.
As one example of the purpose of local noise ordinances,
the noise policy statement in the March 1998
New York City noise code [23.186] is reproduced below.
This noise code is being revised.
24-202 Declaration of policy. It is hereby declared to
be the public policy of the city to reduce the ambient
noise level in the city, so as to preserve, protect and
promote the public health, safety and welfare, and the
peace and quiet of the inhabitants of the city, prevent
injury to human, plant and animal life and property,
foster the convenience and comfort of its inhabitants,
and facilitate the enjoyment of the natural attractions
of the city. It is the public policy of the city that every
person is entitled to ambient noise levels that are not
detrimental to life, health and enjoyment of his or her
property. It is hereby declared that the making, creation
or maintenance of excessive and unreasonable noises
within the city affects and is a menace to public health,
comfort, convenience, safety, welfare and the prosperity
of the people of the city. For the purpose of controlling
and reducing such noises, it is hereby declared to be the
policy of the city to set the unreasonable noise standards
and decibel levels contained herein and to consolidate
certain of its noise control legislation into this code. The
necessity for legislation by enactment of the provisions
of this chapter is hereby declared as matter of legislative
determination.
Noise Policies in Other Countries. Most industrialized
countries have published noise regulations for a variety
of sources. Gottlob [23.187] as well as Flindell
and McKenzie [23.188] have presented information
on community noise regulations in a large number
of countries, and have listed the noise descriptors in
use. More recently, technical study group 3 of the
International Institute of Noise Control Engineering (I-
INCE) prepared a comprehensive draft report on noise
policies and regulations worldwide [23.189]. This report
documents the results of an international survey
on current environmental noise policies and regulations,
and describes some similarities and differences
in noise policies that exist at the global level. It also