A.
Preamble. The Department recognizes that the construction,
operation and maintenance of developments may cause excessive noise that could
degrade the health and welfare of nearby neighbors. It is the intent of the
Department to require adequate provision for the control of excessive
environmental noise from developments proposed after the effective date of this
regulation.
B.
Applicability
(1) This
regulation applies to proposed developments within municipalities without a
local quantifiable noise standard and in unorganized areas of the State. When a
proposed development is located in a municipality which has duly enacted by
ordinance an applicable quantifiable noise standard, which (1) contains limits
that are not higher than the sound level limits contained in this regulation by
more than 5 dBA, and (2) limits or addresses the various types of noises
contained in this regulation or all the types of noises generated by the
development, that local standard, rather than this regulation, shall be applied
by the Department within that municipality for each of the types of sounds the
ordinance regulates. This regulation applies to developments located within one
municipality when the noise produced by the development is received in another
municipality and, in these cases, the Department will also take into
consideration the municipalities' quantifiable noise standards, if
any.
(2) This regulation applies to
expansions and modifications of developments when such expansions and
modifications are proposed after the effective date of this regulation and
subject to site location approval, but only to the noise produced by the
proposed expansion or modification of the development, unless (1) the existing
development was constructed since 1-1-70 and (2) at the time of construction,
the existing development was too small to require site location approval. In
situations where conditions (1) and (2) above apply, then this regulation
applies to the whole development (both existing facility and proposed expansion
or modification). This regulation also applies to expansions and modifications
of existing developments when such expansions and modifications require an
amendment to the development's Site Law permit, but only to the noise produced
by the expansion or modification.
(3) This regulation does not apply to
existing developments or portions of existing developments constructed prior to
1-1-70 or approved under the Site Law prior to the effective date of this
regulation. This regulation does not apply to relicensing of existing solid
waste facilities previously approved under the Site Law.
(4) The sound level limits contained in this
regulation apply only to areas that are defined as protected locations, and to
property lines of the proposed development or contiguous property owned by the
developer, whichever are farther from the proposed development's regulated
sound sources.
(5) The sound level
limits contained in this regulation do not apply to noise received within the
development boundary.
NOTE: The Department will reconsider the effect
and operation of the regulation one year from its effective date.
C.
Sound Level
Limits
(1)
Sound From Routine
Operation of Developments(a) Except as
noted in subsections (b) and (c) below, the hourly sound levels resulting from
routine operation of the development and measured in accordance with the
measurement procedures described in subsection H shall not exceed the following
limits:
(i) At any property line of the
development or contiguous property owned by the developer, whichever is farther
from the proposed development's regulated sound sources:
75 dBA at any time of day.
(ii) At any protected location in an area for
which the zoning, or, if unzoned, the existing use or use contemplated under a
comprehensive plan, is not predominantly commercial, transportation, or
industrial;
60 dBA between 7:00 a.m. and 7:00 p.m.
(the "daytime hourly limit"), and
50 dBA between 7:00 p.m. and 7:00 a.m.
(the "nighttime hourly limit").
(iii) At any protected location in an area
for which the zoning, or, if unzoned, the existing use or use contemplated
under a comprehensive plan, is predominantly commercial, transportation, or
industrial:
70 dBA between 7:00 a.m. and 7:00 p.m.
(the "daytime hourly limit"), and
60 dBA between 7:00 p.m. and 7:00 a.m.
(the 'nighttime hourly limit').
(iv) For the purpose of determining whether
the use of an unzoned area is predominantly commercial, transportation, or
industrial (e.g. non-residential in nature), the Department shall consider the
municipality's comprehensive plan, if any. Further more, the usage of
properties abutting each protected location shall be determined, and the limits
applied for that protected location shall be based upon the usage occurring
along the greater portion of the perimeter of that parcel; in the event the
portions of the perimeter are equal in usage, the limits applied for that
protected location shall be those for a protected location in an area for which
the use is not predominantly commercial, transportation, or
industrial.
(v) When a proposed
development is to be located in an area where the daytime pre-development
ambient hourly sound level at a protected location is equal to or less than 45
dBA and/or the nighttime pre-development ambient hourly sound level at a
protected location is equal to or less than 35 dBA, the hourly sound levels
resulting from routine operation of the development and measured in accordance
with the measurement procedures described in subsection H shall not exceed the
following limits at that protected location:
55 dBA between 7:00 a.m. and 7:00 p.m.
(the "daytime hourly limit"), and
45 dBA between 7:00 p.m. and 7:00 a.m.
(the "nighttime hourly limit").
For the purpose of determining whether a protected location
has a daytime or nighttime pre-development ambient hourly sound level equal to
or less than 45 dBA or 35 dBA, respectively, the developer may make sound level
measurements in accordance with the procedures in subsection H or may estimate
the sound-level based upon the population density and proximity to local
highways. If the resident population within a circle of 3,000 feet radius
around a protected location is greater than 300 persons, or the hourly sound
level from highway traffic at a protected location is predicted to be greater
than 45 dBA in the daytime or 35 dBA at night (as appropriate for the
anticipated operating schedule of the development), then the developer may
,estimate the daytime or nighttime pre-development ambient hourly sound level
to be greater than 45 dBA or 35 dBA, respectively.
NOTE: Highway traffic noise can be predicted
using the nomograph method of FHWA Highway Traffic Noise Prediction Model,
FHWA-RD-77-108, December, 1978.
(vi) Notwithstanding the above, the developer
need not measure or estimate the pre-development ambient hourly sound levels at
a protected location if he demonstrates, by estimate or example, that the
hourly sound levels resulting from routine operation of the development will
not exceed 50 dBA in the daytime or 40 dBA at night.
(b) If the developer chooses to demonstrate
by measurement that the daytime and/or nighttime pre-development ambient sound
environment at any protected location near the development site exceeds the
daytime and/or nighttime limits in subsection
1(a)(ii) or
1(a)(iii) by at least
5 dBA, then the daytime and/or nighttime limits shall be 5 dBA less than the
measured daytime and/or nighttime pre-development ambient hourly sound level at
the location of the measurement for the corresponding time period.
(c) For any protected location near an
existing development, the hourly sound level limit for routine operation of the
existing development and all future expansions of that development shall be the
applicable hourly sound level limit of 1(a) or l(b) above, or, at the
developer's election, the existing hourly sound level from routine operation of
the existing development plus 3 dBA.
(d) For the purposes of determining
compliance with the above sound level limits, 5 dBA shall be added to the
observed levels of any tonal sounds that result from routine operation of the
development.
(e) When routine
operation of a development produces short duration repetitive sound, the
following limits shall apply:
(i) For short
duration repetitive sounds, 5 dBA shall be added to the observed levels of the
short duration repetitive sounds that result from routine operation of the
development for the purposes of determining compliance with the above sound
level limits.
(ii) For short
duration repetitive sounds resulting from scrap metal, drop forge and metal
fabrication operations or developments which the Department determines, due to
their character and/or duration, are particularly annoying or pose a threat to
the health and welfare of nearby neighbors, 5 dBA shall be added to the
observed levels of the short duration repetitive sounds that result from
routine operation of the development for the purposes of determining compliance
with the above sound level limits, and the maximum sound level of the short
duration repetitive sounds shall not exceed the following limits:
(a) At any protected location in an area for
which the zoning, or, if unzoned, the existing use or use contemplated under a
comprehensive plan, is not predominantly commercial, transportation, or
industrial:
65 dBA between 7:00 a.m. and 7:00 p.m., and
55 dBA between 7:00 p.m. and 7:00 a.m.
(b) At any protected location in an area for
which the zoning, or, if unzoned, the existing use or use contemplated under a
comprehensive plan, is predominantly commercial, transportation, or industrial:
75 dBA between 7:00 a.m. and 7:00 p.m., and
65 dBA between 7:00 p.m. and 7:00 a.m.
(c) The methodology described in subsection
1(a)(iv) shall be
used to determine whether the use of an unzoned area is predominantly
commercial, transportation, or industrial.
(d) If the developer chooses to demonstrate
by measurement that the pre-development ambient hourly sound level at any
protected location near the development site exceeds 60 dBA between 7:00 a.m.
and 7:00 p.m., and/or 50 dBA between 7:00 p.m. and 7:00 a.m., then the maximum
sound level limit for short duration repetitive sound shall be 5 dBA greater
than the measured pre-development ambient hourly sound level at the location of
the measurement for the corresponding time period.
(e) For any protected location near an
existing development, the maximum sound level limit for short duration
repetitive sound resulting from routine operation of the existing development
and all future expansions and modifications of that development shall be the
applicable maximum sound level limit of (e)(ii)(a) or (e)(ii)(b) above, or, at
the developer's election, the existing maximum sound level of the short
duration repetitive sound resulting from routine operation of the existing
development plus 3 dBA.
NOTE: The maximum sound level of the short
duration repetitive sound shall be measured using the fast response
[LAFmax].See the definition of maximum sound
level.
(2)
Sound From Construction of
Developments
(a) The sound from
construction activities between 7:00 p.m. and 7:00 a.m. is subject to the
following limits:
(i) Sound from nighttime
construction activities shall be subject to the nighttime routine operation
sound level limits contained in subsections l(a) and 1(b).
(ii) If construction activities are conducted
concurrently with routine operation, then the combined total of construction
and routine operation sound shall be subject to the nighttime routine operation
sound level limits contained in subsections
1(a) and
1(b).
(iii) Higher levels of nighttime construction
sound are permitted when a duly issued permit authorizing nighttime
construction sound in excess of these limits has been granted by:
1. the local municipality when the duration
of the nighttime construction activity is less than or equal to 90
days,
2. the local municipality and
the Department when the duration of the nighttime construction activity is
greater than 90 days.
(b) Sound from construction activities
between 7:00 a.m. and 7:00 p.m. shall not exceed the following limits at any
protected location:
|
Duration of Activity |
Hourly Sound Level Limit |
|
12 hours |
87 dBA |
|
8 hours |
90 dBA |
|
6 hours |
92 dBA |
|
4 hours |
95 dBA |
|
3 hours |
97 dBA |
|
2 hours |
100 dBA |
|
1 hour or less |
105 dBA |
(c)
All equipment used in construction on development sites shall comply with
applicable federal noise regulations and shall include environmental noise
control devices in proper working condition, as originally provided with the
equipment by its manufacturer.
(3)
Sound From Maintenance
Activities
(a) Sound from routine,
ongoing maintenance activities shall be considered part of the routine
operation of the development and the combined total of the routine maintenance
and operation sound shall be subject to the routine operation sound level
limits contained in subsection 1.
(b) Sound from occasional, major, scheduled
overhaul activities shall be subject to the construction sound level limits
contained in subsection
2. If overhaul activities are
conducted concurrently with routine operation and/or construction activities,
the combined total of the overhaul, routine operation and construction sound
shall be subject to the construction sound level limits contained in subsection
2.
(4)
Sound From Production
Blasting
Sound exceeding the limits of subsection
1 and resulting from production
blasting at a mine or quarry shall be limited as follows:
(a) Blasting shall not occur in the period
between sundown and sunrise the following day or in the period between the
hours of 7:00 p.m. and 7:00 a.m., whichever is greater. In addition, no routine
production blasting shall be allowed in the daytime on Sundays.
(b) Blasting shall not occur more frequently
than four times per day.
(c) Sound
from blasting shall not exceed the following limits at any protected location:
|
Number of Blasts Per Day |
Sound Level Limit |
|
1 |
129 dBL |
|
2 |
126 dBL |
|
3 |
124 dBL |
|
4 |
123 dBL. |
Blast sound shall be measured in peak linear sound level
(dBL) with a linear response down to 5 Hz.
NOTE: See Bureau of Mines Report of
Investigations 8485 for information on airblast sound levels and pertinent
scaled distances.
(5)
Exemptions
Sound associated with the following shall be exempt from
regulation by the Department:
(a)
Railroad equipment which is subject to federal noise regulations.
(b) Aircraft operations which are subject to
federal noise regulations.
(c)
Registered and inspected vehicles:
(i) while
operating on public ways, or
(ii)
which enter the development to make a delivery or pickup and which are moving,
starting or stopping, but not when they are parked for over 60 minutes in the
development.
(d)
Watercraft while underway.
(e)
Residential developments, except during construction of such
developments.
(f) Bells, chimes and
carillons.
(g) occasional sporting,
cultural, religious or public events allowed by the local municipality where
the only affected protected locations are contained within that
municipality.
(h) The unamplified
human voice and other sounds of natural origin.
(i) Firming, fishing and aquacultural
activity.
(j) Forest management,
harvesting and transportation activities.
(k) Making, maintaining and grooming snow
where the only affected protected locations are contained within the general
boundaries of a ski area development.
(l) Snow removal, landscaping and street
sweeping activities.
(m) Emergency
maintenance and repairs.
(n)
Warning signals and alarms.
(o)
Safety and protective devices installed in accordance with code
requirements.
(p) Test operations
of emergency equipment occurring in the daytime and no more frequently than
once per week.
(q) Boiler start-up,
testing and maintenance operations occurring no more frequently than once per
month.
(r) Major concrete pours
that must extend after 7:00 p.m., when started before 3:00 p.m.
(s) Sounds from a regulated development
received at a protected location when the generator of the sound has been
conveyed a noise easement for that location. This exemption shall only be for
the specific noise, land and term covered by the easement.
(t) A force majeure event and other causes
not reasonably within the control of the owners or operators of the
development.
(6)
Noise Abatement Structures
Noise abatement structures of a non-permanent nature in any
one location for a duration of less than one year and erected for the sole
purpose of noise control shall not be considered structures as defined in
38 M.R.S.A.
subsection482(6).
D.
Submissions
(1)
Developments with Minor Sound Impact
An applicant for a proposed development with minor sound
impact may choose to file as part of the site location application a statement
attesting to the minor nature of the anticipated sound impact of their
development. An applicant proposing an expansion or modification of an existing
development with minor sound impact may follow the same procedure as described
above. For the purpose of this regulation, a development or an expansion or
modification of an existing development with minor sound impact means a
development where the developer demonstrates, by estimate or example, that the
regulated sound from routine operation of the development will not exceed 5 dBA
less than the applicable limits established under subsection C. It is the
intent of this subsection that an applicant need not conduct sound level
measurements to demonstrate that the development or an expansion or
modification of an existing development will have a minor sound impact.
NOTE: Examples include subdivisions without
structures, office buildings, storage buildings which will not normally be
accessed at night, and golf courses.
(2)
Other Developments
Technical information shall be submitted describing the
applicant's plan and intent to make adequate provision for the control of
sound. The applicant's plan shall contain information such as the following,
when appropriate:
(a) Maps and
descriptions of the land uses, local zoning and comprehensive plans for the
area potentially affected by sounds from the development.
(b) A description of major sound sources,
including tonal sound sources and sources of short duration repetitive sounds,
associated with the construction, operation and maintenance of the proposed
development, including their locations within the proposed
development.
(c) A description of
the daytime and nighttime hourly sound levels and, for short duration
repetitive sounds, the maximum sound levels expected to be produced by these
sound sources at protected locations near the proposed development.
(d) A description of the protected locations
near the proposed development.
(e)
A description of proposed major sound control measures, including their
locations and expected performance.
(f) A comparison of the expected sound levels
from the proposed development with the sound level limits of this
regulation.
(g) A comparison of the
expected sound levels from the proposed development with any quantifiable noise
standards of the municipality in which the proposed development will be located
and of any municipality which may be affected by the noise.
E.
Terms and
Conditions
The Department may, as a term or condition of approval,
establish any reasonable requirement to ensure that the developer has made
adequate provision for the control of noise from the development and to reduce
the impact of noise on protected locations. Such conditions may include, but
are not limited to, enclosing equipment or operations, imposing limits on hours
of operation, or requiring the employment of specific design technologies, site
design, modes of operation, or traffic patterns.
The sound level limits prescribed in this regulation shall
not preclude the Department under Chapter 375.15 from requiring a developer to
demonstrate that sound levels from a development will not unreasonably disturb
wildlife or adversely affect wildlife populations. In addition, the sound level
limits shall not preclude the Department, as a term or condition of approval,
from requiring that lower sound level limits be met to ensure that the
developer has made adequate provision for the protection of wildlife.
F.
Variance From Sound Level
Limits
The Department recognizes that there are certain
developments or activities associated with development for which noise control
measures are not reasonably available. Therefore, the Department may grant a
variance from any of the sound level limits contained in this rule upon (1) a
showing by the applicant that he or she has made a comprehensive assessment of
the available technologies for the development and that the sound level limits
cannot practicably be met with any of these available technologies, and (2) a
finding by the Department that the proposed development will not have an
unreasonable impact on protected locations. In addition, a variance may be
granted by the Department if (1) a development is deemed necessary in the
interest of national defense or public safety and the applicant has shown that
the sound level limits cannot practicably be met without unduly limiting the
development's intended function, and (2) a finding is made by the Department
that the proposed development will not have an unreasonable impact on protected
locations. The Department shall consider the request for a variance as part of
the review of a completed Site Location of Development Law application. In
granting a variance, the Department may, as a condition of approval, impose
terms and conditions to ensure that no unreasonable sound impacts will
occur.
G.
Definitions
Terms used herein are defined below for the purpose of this
noise regulation.
(1)
AMBIENT
SOUND: At a specified time, the all-encompassing sound associated with a
given environment, being usually a composite of sounds from many sources at
many directions, near and far, including the specific development of
interest.
(2)
CONSTRUCTION: Activity and operations associated with the
development or expansion of a project or its site.
(3)
EMERGENCY: An unforeseen
combination of circumstances which calls for immediate action.
(4)
EMERGENCY MAINTENANCE AND
REPAIRS: Work done in response to an emergency.
(5)
ENERGY SUM OF A SERIES OF
LEVELS: Ten times the logarithm of the arithmetic sum of the
antilogarithms of one-tenth of the levels. [Note: See Section
H(4.2).]
(6)
EXISTING
DEVELOPMENT: A development constructed before 1-1-70 or a development
approved under the Site Law prior to the effective date of this regulation or a
proposed development for which the site location application is complete for
processing on or before the effective date of this regulation. Any development
with a site location approval which has been remanded to the Department by a
court of competent jurisdiction for further proceedings relating to noise
limits or noise levels prior to the effective date of these regulations shall
not be deemed an existing development and these regulations shall apply to the
existing noise sources at that development.
(7)
EXISTING HOURLY SOUND LEVEL:
The hourly sound level resulting from routine operation of an existing
development prior to the first expansion that is subject to this
regulation.
(8)
EQUIVALENT
SOUND LEVEL: The level of the mean-square A-weighted sound pressure
during a stated time period, or equivalently the level of the sound exposure
during a stated time period divided by the duration of the period.
NOTE: For convenience, a one hour equivalent
sound level should begin approximately on the hour.
(9)
HISTORIC AREAS: Historic
sites administered by the Bureau of Parks and Recreation of the Maine
Department of Conservation, with the exception of the Arnold Trail.
(10)HOURLY SOUND LEVEL: The
equivalent sound level for one hour measured or computed in accordance with
this regulation.
(11)
LOCALLY-DESIGNATED PASSIVE
RECREATION AREA: Any site or area designated by a municipality for
passive recreation that is open and maintained for public use and which:
(a) has fixed boundaries,
(b) is owned in fee simple by a municipality
or is accessible by virtue of public easement,
(c) is identified and described in a local
comprehensive plan, and
(d) has
been identified and designated at least nine months prior to the filing of the
applicant's Site Location of Development application.
(12)MAXIMUM SOUND LEVEL: Ten
times the common logarithm of the square of the ratio of the maximum sound to
the reference sound of 20 micropascals. Symbol: LAFmax.
(13)MAXIMUM SOUND: Largest
A-weighted and fast exponential-time-weighted sound during a specified time
interval. Unit: pascal (Pa).
(14)RESIDENCE: A building or
structure, including manufactured housing, maintained for permanent or seasonal
residential occupancy providing living, cooking and sleeping facilities and
having permanent indoor or outdoor sanitary facilities, excluding recreational
vehicles, tents and watercraft.
(15)PRE-DEVELOPMENT AMBIENT: The
ambient sound at a specified location in the vicinity of a development site
prior to the construction and operation of the proposed development or
expansion.
(16)
PROTECTED
LOCATION: Any location, accessible by foot, on a parcel of land
containing a residence or planned residence or approved residential
subdivision, house of worship, academic school, college, library, duly licensed
hospital or nursing home near the development site at the time a Site Location
of Development application is submitted; or any location within a State Park,
Baxter State Park, National Park, Historic Area, a nature preserve owned by the
Maine or National Audubon Society or the Maine Chapter of the Nature
Conservancy, The Appalachian Trail, the Moosehorn National Wildlife Refuge,
federally-designated wilderness area, state wilderness area designated by
statute (such as the Allagash Wilderness Waterway), or locally-designated
passive recreation area; or any location within consolidated public reserve
lands designated by rule by the Bureau of Public Lands as a protected location.
At protected locations more than 500 feet from living and
sleeping quarters within the above noted buildings or areas, the daytime hourly
sound level limits shall apply regardless of the time of day.
Houses of worship, academic schools, libraries, State and
National Parks without camping areas, Historic Areas, nature preserves, the
Moosehorn National Wildlife Refuge, federally-designated wilderness areas
without camping areas, state wilderness areas designated by statute without
camping areas, and locally-designated passive recreation areas without camping
areas are considered protected locations only during their regular hours of
operation and the daytime hourly sound level limits shall apply regardless of
the time of day.
Transient living accommodations are generally not considered
protected locations; however, in certain special situations where it is
determined by the Department that the health and welfare of the guests and/or
the economic viability of the establishment will be unreasonably impacted, the
Department may designate certain hotels, motels, campsites and duly licensed
campgrounds as protected locations.
This term does not include buildings and structures located
on leased camp lots, owned by the applicant, used for seasonal purposes.
For purposes of this definition, (1) a residence is
considered planned when the owner of the parcel of land on which the residence
is to be located has received all applicable building and land use permits and
the time for beginning construction under such permits has not expired, and (2)
a residential subdivision is considered approved when the developer has
received all applicable land use permits for the subdivision and the time for
beginning construction under such permits has not expired.
(17)QUANTIFIABLE NOISE STANDARD:
A numerical limit governing noise from developments that has been duly enacted
by ordinance by a local municipality.
(18)ROUTINE OPERATION: Regular
and recurrent operation of regulated sound sources associated with the purpose
of the development and operating on the development site.
(19)SHORT DURATION REPETITIVE
SOUNDS: A sequence of repetitive sounds which occur more than once
within an hour, each clearly discernible as an event and causing an increase in
the sound level of at least 6 dBA on the fast meter response above the sound
level observed immediately before and after the event, each typically less than
ten seconds in duration, and which are inherent to the process or operation of
the development and are foreseeable.
(20)SOUND COMPONENT: The
measurable sound from an audibly identifiable source or group of
sources.
(21)SOUND
LEVEL: Ten times the common logarithm of the square of the ratio of the
frequency-weighted and time-exponentially averaged sound pressure to the
reference sound of 20 micropascals. For the purpose of this regulation, sound
level measurements are obtained using the A-weighted frequency response and
fast dynamic response of the measuring system, unless otherwise
noted.
(22)SOUND
PRESSURE: Root-mean-square of the instantaneous sound pressures in a
stated frequency band and during a specified time interval. Unit: pascal
(Pa).
(23)SOUND PRESSURE
LEVEL: Ten times the common logarithm of the square of the ratio of the
sound pressure to the reference sound pressure of 20 micropascals.
(24)
TONAL SOUND: for the purpose
of this regulation, a tonal sound exists if, at a protected location, the
one-third octave band sound pressure level in the band containing the tonal
sound exceeds the arithmetic average of the sound pressure levels of the two
contiguous one-third octave bands by 5 dB for center frequencies at or between
500 Hz and 10,000 Hz, by 8 dB for center frequencies at or between 160 and 400
Hz, and by 15 dB for center frequencies at or between 25 Hz and 125 Hz.
Additional acoustical terms used in work associated with
this regulation shall be used in accordance with the following American
National Standards Institute (ANSI) standards:
ANSI S12.9-1988 - American National Standard Quantities and
Procedures for Description and Measurements of Environmental Sound, Part
1;
ANSI S3.20-1973 - American National Standard
Psychoacoustical Terminology;
ANSI S1.1-1960 - American National Standard Acoustical
Terminology.
H.
Measurement Procedures
(1)
Scope. These procedures specify measurement criteria and
methodology for use, with applications, compliance testing and enforcement.
They provide methods for measuring the ambient sound and the sound from routine
operation of the development, and define the information to be reported. The
same methods shall be used for measuring the sound of construction, maintenance
and production blasting activities. For measurement of the sound of production
blasting activities for comparison with the limits of subsection C(4)(c), these
same methods shall be used with the substitution of the linear sound level for
the A-weighted sound level.
(2)
Measurement Criteria2.1
Measurement Personnel
Measurements shall be supervised by personnel who are well
qualified by training and experience in measurement and evaluation of
environmental sound, or by personnel trained to operate under a specific
measurement plan approved by the Department.
2.2
Measurement Instrumentation
(a) A sound level meter or alternative sound
level measurement system used shall meet all of the Type 1 or 2 performance
requirements of American National Standard Specifications for Sound Level
Meters, ANSI S1.4-1983.
(b) An
integrating sound level meter (or measurement system) shall also meet the Type
1 or 2 performance requirements for integrating/averaging in the International
Electro technical Commission Standard on Integrating-Averaging Sound Level
Meters, IEC Publication 804 (1985).
(c) A filter for determining the existence of
tonal sounds shall meet all the requirements of-American National Standard
Specification for Octave-Band and Fractional Octave-Band Analog and Digital
Filters, ANSI S1.11-1986 for Order 3, Type 3-D performance.
(d) An acoustical calibrator shall be used of
a type recommended by the manufacturer of the sound level meter and that meets
the requirements of American National Standard Specification for Acoustical
Calibrators, ANSI S1.40-1984.
(e) A
microphone windscreen shall be used of a type recommended by the manufacturer
of the sound level meter.
2.3
Calibration
(a) The sound level meter shall have been
calibrated by a laboratory within 12 months of the measurement, and the
microphone's response shall be traceable to the National Bureau of
Standards.
(b) Field calibrations
shall be recorded before and after each measurement period and at shorter
intervals if recommended by the manufacturer.
2.4
Measurement Location, Configuration
and Environment
(a) Except as noted in
subsection (b) below, measurement locations shall be at nearby protected
locations that are most likely affected by the sound from routine operation of
the development.
(b) For
determining compliance with the 75 dBA property line hourly sound level limit
described in subsection C(l)(a)(i), measurement locations shall be selected at
the property lines of the proposed development or contiguous property owned by
the developer, as appropriate.
(c)
The microphone shall be positioned at a height of approximately 4 to 5 feet
above the ground, and oriented in accordance with the manufacturer's
recommendations.
(d) Measurement
locations should be selected so that no vertical reflective surface exceeding
the microphone height is located within 30 feet. When this is not possible, the
measurement location may be closer than 30 feet to the reflective surface, but
under no circumstances shall it be closer than 6 feet.
(e) When possible, measurement locations
should be at least 50 feet from any regulated sound source on the
development.
(f) Measurement
periods shall be avoided when the local wind speed exceeds 12 mph and/or
precipitation would affect the measurement results.
2.5
Measurement Plans.Plans for
measurement of pre-development ambient sound or post-development sound may be
discussed with the Department staff.
(3)
Measurement of Ambient Sound
3.1
Pre-Development Ambient
Sound
Measurements of the pre-development ambient sound are
required only when the developer elects to establish the sound level limit in
accordance with subsections C(1)(b) and C(1)(e)(ii)(d) for a development in an
area with high ambient sound levels, such as near highways, airports, or
pre-existing developments; or when the developer elects to establish that the
daytime and nighttime ambient hourly sound levels at representative protected
locations exceed 45 dBA and 35 dBA, respectively.
(a) Measurements shall be made at
representative protected locations for periods of time sufficient to adequately
characterize the ambient sound. At a minimum, measurements shall be made on
three different weekdays (Monday through Friday) during all hours that the
development will operate. If the proposed development will operate on Saturdays
and/or Sundays, measurements shall also be made during all hours that the
development will operate.
(b)
Measurement periods with particularly high ambient sounds, such as during
holiday traffic activity, significant insect activity or high coastline waves,
should generally be avoided.
(c) At
any measurement location the daytime and nighttime ambient hourly sound level
shall be computed by arithmetically averaging the daytime and nighttime values
of the measured one hour equivalent sound levels. Multiple values, if they
exist, for any specific hour on any specific day shall first be averaged before
the computation described above.
3.2
Post-Development Ambient
Sound
(a) Measurements of the
post-development ambient one hour equivalent sound levels and, if short
duration repetitive sounds are produced by the development, the maximum sound
levels made at nearby protected locations and during representative routine
operation of the development that are not greater than the applicable limits of
subsection C clearly indicate compliance with those limits.
(b) Compliance with the limits of subsection
C(l)(b) may also be demonstrated by showing that the post-development ambient
hourly sound level, measured in accordance with the procedures of subsection
3.1 above during routine operation of the development, does not exceed the
pre-development ambient hourly sound level by more than one decibel, and that
the sound from routine operation of the development is not characterized by
either tonal sounds or short duration repetitive sounds.
(c) Compliance with the limits of subsection
C(1)(e)(ii)(d) may also be demonstrated by showing that the post development
maximum sound level of any short duration repetitive sound, measured in
accordance with the procedures of subsection 3.1 above, during routine
operation of the development, does not exceed the pre-development ambient
hourly sound level by more than five decibels.
(d) If any of the conditions in (a), (b) or
(c) above are not met, compliance with respect to the applicable limits must be
determined by measuring the sound from routine operation of the development in
accordance with the procedures described in subsection
4.
(4)
Measurement of the Sound from
Routine Operation of Developments.
4.1
General
(a) Measurements of the
sound from routine operation of developments are generally necessary only for
specific compliance testing purposes in the event that community complaints
result from operation of the development, for validation of an applicant's
calculated sound levels when requested by the Department, for determination of
existing hourly sound levels for an existing development or for enforcement by
the Department.
(b) Measurements
shall be obtained during representative weather conditions when the development
sound is most clearly noticeable. Preferable weather conditions for sound
measurements at distances greater than about 500 feet from the sound source
include overcast days when the measurement location is downwind of the
development and inversion periods (which most commonly occur at
night).
(c) Measurements of the
development sound shall be made so as to exclude the contribution of sound from
development equipment that is exempt from this regulation.
4.2
Measurement of the Sound Levels
Resulting from Routine Operation of the Development
(a) When the ambient sound levels are greater
than the sound level limits, additional measurements can be used to determine
the hourly sound level that results from routine operation of the development.
These additional measurements may include diagnostic measurements such as
measurements made close to the development and extrapolated to the protected
location, special checkmark measurement techniques that include the separate
identification of audible sound sources, or the use of sound level meters with
pause capabilities that allow the operator to exclude non-development
sounds.
(b) For the purposes of
computing the hourly sound level resulting from routine operation of the
development, sample diagnostic measurements may be made to obtain the one hour
equivalent sound levels for each sound component.
(c) Identification of tonal sounds produced
by the routine operation of a development for the purpose of adding the 5 dBA
penalty in accordance with subsection C(l)(d) requires aural perception by the
measurer, followed by use of one-third octave band spectrum analysis
instrumentation. If one or more of the sounds of routine operation of the
development are found to be tonal sounds, the hourly sound level component for
tonal sounds shall be computed by adding 5 dBA to the one hour equivalent sound
level for those sounds.
(d)
Identification of short duration repetitive sounds produced by routine
operation of a development requires careful observations. For the sound to be
classified as short duration repetitive sound, the source(s) must be inherent
to the process or operation of the development and not the result of an
unforeseeable occurrence. If one or more of the sounds of routine operation of
the development are found to be short duration repetitive sounds, the hourly
sound level component for short duration repetitive sounds shall be computed by
adding 5 dBA to the one hour equivalent sound level for those sounds. If
required, the maximum sound levels of short duration repetitive sounds shall be
measured using the fast response [LAFmax]. The duration and the frequency of
occurrence of the events shall also be measured. In some cases, the sound
exposure levels of the events may be measured. The one hour equivalent sound
level of a short duration repetitive sound may be determined from measurements
of the maximum sound level during the events, the duration and frequency of
occurrence of the events, and their sound exposure levels.
(e) The daytime or nighttime hourly sound
level resulting from routine operation of a development is the energy sum of
the hourly sound level components from the development, including appropriate
penalties, (see (c) and (d) above). If the energy sum does not exceed the
appropriate daytime or nighttime sound level limit, then the development is in
compliance with that sound level limit at that protected location.
(5)
Reporting
Sound Measurement Data. The sound measurement data report should include
the following:
(a) The dates, days of the
week and hours of the day when measurements were made.
(b) The wind direction and speed,
temperature, humidity and sky condition.
(c) Identification of all measurement
equipment by make, model and serial number.
(d) The most recent dates of laboratory
calibration of sound level measuring equipment.
(e) The dates, times and results of all field
calibrations during the measurements.
(f) The applicable sound level limits,
together with the appropriate hourly sound levels and the measurement data from
which they were computed, including data relevant to either tonal or short
duration repetitive sounds.
(g) A
sketch of the site, not necessarily to scale, orienting the development, the
measurement locations, topographic features and relevant distances, and
containing sufficient information for another investigator to repeat the
measurements under similar conditions.
(h) A description of the sound from the
development and the existing environment by character and location.
I.
Sound Level
Standards for Wind Energy Developments
(1)
Applicability
This subsection applies to grid-scale wind energy
developments as defined by
35-A M.R.S.A.
§3451(6) and
small-scale wind energy developments governed by
35-A
M.R.S.A. §3456, hereinafter referred to
as "wind energy developments. "The provisions in Section
10(C)(1),
10(D)(2),
10(F), and
10(H) of this rule
do not apply to wind energy developments.
(2)
Sound Level Limits for Routine
Operation of Wind Energy Developments
The sound levels resulting from routine operation of a wind
energy development measured in accordance with the measurement procedures
described in subsection I(8) shall not exceed the following limits:
(a) 75 dBA at any time of day at any property
line of the wind energy development or contiguous property owned or controlled
by the wind energy developer, whichever is farther from the proposed wind
energy development's regulated sound sources; and
(b) 55 dBA between 7:00 a.m. and 7:00 p.m.
(the "daytime limit"), and 42 dBA between 7:00 p.m. and 7:00 a.m. (the
"nighttime limit") at any protected location.
(3)
Tonal Sounds
For the purposes of this subsection, a tonal sound exists if,
at a protected location, the 10 minute equivalent average one-third octave band
sound pressure level in the band containing the tonal sound exceeds the
arithmetic average of the sound pressure levels of the two contiguous one-third
octave bands by 5 dB for center frequencies at or between 500 Hz and 10,000 Hz,
by 8 dB for center frequencies at or between 160 and 400 Hz, and by 15 dB for
center frequencies at or between 25 Hz and 125 Hz. 5 dBA shall be added to any
average 10 minute sound level (LeqA 10-min) for which a
tonal sound occurs that results from routine operation of the wind energy
development.
(4)
Short Duration Repetitive Sounds ("SDRS")
For the purposes of this subsection SDRS is defined as a
sequence of repetitive sounds that occur within a 10-minute measurement
interval, each clearly discernible as an event resulting from the development
and causing an increase in the sound level of 5 dBA or greater on the fast
meter response above the sound level observed immediately before and after the
event, each typically ±1 second in duration, and which are inherent to
the process or operation of the development.
(a) When routine operation of a wind energy
development produces short duration repetitive sound, a 5 dBA penalty shall be
arithmetically added to each average 10-minute sound level (LeqA
10-min) measurement interval in which greater than 5 SDRS events
are present.
(5)
Compliance with the Sound Level Limits
A wind energy development shall determine compliance with the
sound level limits as set forth in subsection I(2) of this rule in accordance
with the following:
(a) Sound level
data shall be aggregated in 10-minute measurement intervals within a given
compliance measurement period (daytime: 7:00 am to 7:00 pm or nighttime: 7:00
pm to 7:00 am) under the conditions set forth in subsection I(8) of this
rule.
(b) Compliance will be
demonstrated when the arithmetic average of the sound level of, at a minimum,
twelve, 10-minute measurement intervals in a given compliance measurement
period is less than or equal to the sound level limit set forth in subsection
I(2).
(c) Alternatively, if a given
compliance measurement period does not produce a minimum of twelve, 10-minute
measurement intervals under the atmospheric and site conditions set forth in
subsection I(8) of this rule, the wind energy development may combine six or
more contiguous 10-minute measurement intervals from one 12 hour (7:00 am to
7:00 pm daytime or 7:00 pm to 7:00 am nighttime) compliance measurement period
with six or more contiguous 10-minute intervals from another compliance
measurement period. Compliance will be demonstrated when the arithmetic average
of the combined 10-minute measurement intervals is less than or equal to the
sound level limit set forth in subsection I(2).
(6)
Variance from Sound Level
Limits
A variance may be granted by the Department if:
(1) a development is deemed necessary in the
interest of national defense or public safety and the applicant has shown that
the sound level limits cannot practicably be met without unduly limiting the
development's intended function, and (2) a finding is made by the Department
that the proposed development will not have an unreasonable impact on protected
locations. The Department shall consider the request for a variance as part of
the review of a completed Site Location of Development Law application or a
request for certification for a small-scale wind energy development. In
granting a variance, the Department may, as a condition of approval, impose
terms and conditions to ensure that no unreasonable sound impacts will
occur.
(7)
Submissions
Technical information shall be submitted describing the wind
energy developer's plan and intent to make adequate provision for the control
of sound. The wind energy developer's plan shall contain the following:
(a) A map depicting the location of all
proposed sound sources associated with the wind energy development, property
boundaries for the proposed wind energy development, property boundaries of all
adjacent properties within one mile of the proposed wind energy development,
and the location of all protected locations located within one mile of the
proposed wind energy development;
(b) A description of the major sound sources,
including tonal sound sources and sources of short duration repetitive sounds,
associated with the construction, operation and maintenance of the proposed
wind energy development;
(c) A
description of the equivalent noise levels expected to be produced by the sound
sources at protected locations located within one mile of the proposed wind
energy development. The description shall include a full-page isopleths map
depicting the modeled decay rate of the predicted sound pressure levels
expected to be produced by the wind energy development at each clearly
identified protected location within one mile of the proposed wind energy
development. The predictive model used to generate the equivalent noise levels
expected to be produced by the sound sources shall be designed to represent the
"predictable worst case" impact on adjacent properties and shall include, at a
minimum, the following:
1. The maximum rated
sound power output (IEC 61400-11) of the sound sources operating during
nighttime stable atmospheric conditions with high wind shear above the boundary
layer and consideration of other conditions that may affect in-flow airstream
turbulence;
2. Attenuation due to
geometric spreading, assuming that each turbine is modeled as a point source at
hub height;
3. Attenuation due to
air absorption;
4. Attenuation due
to ground absorption/reflection;
5.
Attenuation due to three dimensional terrain;
6. Attenuation due to forestation;
7. Attenuation due to meteorological factors
such as but not limited to relative wind speed and direction (wind rose data),
temperature/vertical profiles and relative humidity, sky conditions, and
atmospheric profiles;
8. Inclusion
of an "uncertainty factor" adjustment to the maximum rated output of the sound
sources based on the manufacturer's recommendation; and
9. Inclusion, at the discretion of the
Department, of an addition to the maximum rated output of the sound sources to
account for uncertainties in the modeling of sound propagation for wind energy
developments. This discretionary uncertainty factor of up to 3 dBA may be
required by the Department based on the following conditions:inland or coastal
location, the extent and specificity of credible evidence of meteorological
operating conditions, and the extent of evaluation and/or prior specific
experience for the proposed wind turbines. Subject to the Department's
discretion based on the information available, there is a rebuttable
presumption of an uncertainty factor of 2 to 3 dBA for coastal developments and
of 0 to 2 dBA for inland developments.
(d) A description of the protected locations
near the proposed wind energy development.
(e) A description of proposed major sound
control measures, including their locations and expected performance.
(f) A comparison of the expected sound levels
from the proposed development with the sound level limits of this
regulation.
(g) A comparison of the
expected sound levels from the proposed development with any quantifiable noise
standards of the municipality in which the proposed development will be located
and of any municipality which may be affected by the noise.
(h) A description and map identifying one or
more compliance testing locations on or near the proposed wind energy
development site. The identified compliance testing locations shall be selected
to take advantage of prevailing downwind conditions and be able to meet the
site selection criteria outlined in subsection I(8)(d)(2).
(i) A description of the compliance
measurement protocol as required by subsection
8 below.
(j) A description of the complaint response
protocol proposed for the wind energy development. The complaint response
protocol shall adequately provide for, at a minimum:
1. A 24-hour contact for
complaints;
2. A complaint log
accessible by the Department;
3.
For those complaints that include sufficient information to warrant an
investigation, the protocol must provide for an analysis as set forth in (a)
through (c) below. Sufficient information includes, at a minimum: the name and
address of the complainant; the date, time and duration of the sound event; a
description of the sound event, indoor or outdoor, specific location and a
description of any audible sounds from other sources outside or inside the
dwelling of the complainant. Analysis of the complaint by the licensee must
include:
(a) documentation of the location of
the nearest turbines to the complaint location and ground conditions in the
area of the complaint location;
(b)
weather conditions at the time of the complaint and surface and hub height wind
speed and direction;
(c) power
output and direction of nearest turbines; and
(d) notification of complaint findings to the
Department and the complainant;
4. A plotting of complaint locations and key
information on a project area map to evaluate complaints for a consistent
pattern of site, operating and weather conditions; and
5. A comparison of these patterns to the
compliance protocol to determine whether testing under additional site and
operating conditions is necessary and, if so, a testing plan that addresses the
locations and the conditions under which a pattern of complaints had
occurred.
(8)
Measurement Procedures
These procedures specify measurement criteria and methodology
for use with wind energy development applications, compliance and complaint
response. They provide methods for measuring the sound from operation of the
wind energy development and set forth the information to be reported.
(a)
Measurement Criteria
1.
Measurement Personnel
Measurements shall be supervised by personnel who are well
qualified by training and experience in measurement and evaluation of
environmental sound, or by personnel trained to operate under a specific
measurement plan approved by the Department.
(b)
Measurement Instrumentation
1. A sound level meter or alternative sound
level measurement system used shall meet all of the Type 0 or 1 performance
requirements of American National Standard Specifications for Sound Level
Meters, ANSI S1.4.
2. An
integrating sound level meter (or measurement system) shall also meet the Type
0 or 1 performance requirements for integrating/averaging in the International
Electrotechnical Commission Standard on Integrating-Averaging Sound Level
Meters, IEC Publication 61672-1 and ANSI 1.43.
3. A filter for determining the existence of
tonal sounds shall meet all the requirements of the American National Standard
Specification for Octave-Band and Fractional Octave-Band Analog and Digital
Filters, ANSI S1.11 and IEC 61260, Type 3-D performance.
4. The acoustical calibrator used shall be of
a type recommended by the manufacturer of the sound level meter and one that
meets the requirements of American National Standard Specification for
Acoustical Calibrators, ANSI S1.40.
5. The microphone windscreen used shall be of
a type recommended by the manufacturer of the sound level meter.
6. Anemometer(s) used for surface (10 meter
(m)) (32.8 feet) wind speeds shall have a minimum manufacturer specified
accuracy of ±1 mph providing data in one second integrations and 10 min.
average/maximum values for the evaluation of atmospheric stability.
7. Audio recording devices shall be time
stamped (hh:mm:ss) and at a minimum 16 bit digital, recording the sound signal
output from the measurement microphone at a minimum sampling rate of 24
thousand (k) samples per second to be used for identifying events. Audio
recording and compliance data collection shall occur through the same
microphone/sound meter and bear the same time stamp.
(c)
Equipment Calibration
1. The sound level meter shall have been
calibrated by a laboratory within 12 months of the measurement, and the
microphone's response shall be traceable to the National Institute of Standards
and Technology.
3. Field
calibrations shall be recorded before and after each measurement period and at
shorter intervals if recommended by the manufacturer.
4. Anemometer(s) and vane(s) shall be
calibrated annually by the manufacturer to maintain stated
specification.
(d)
Compliance Measurement Location, Configuration, and Environment
1. Compliance measurement locations shall be
at nearby protected locations that are most likely affected by the sound from
routine operation of the wind energy development subject to permission from the
respective property owner(s).
2.
To the greatest extent possible, compliance measurement locations shall be at
the center of unobstructed areas that are maintained free of vegetation and
other structures or material that is greater than 2 feet in height for a
75-foot radius around the sound and audio monitoring equipment.
3. To the greatest extent possible,
meteorological measurement locations shall be at the center of open flat
terrain, inclusive of grass and a few isolated obstacles less than 6 feet in
height for a 250-foot radius around the anemometer location. The meteorological
data measurement location need not be coincident with the sound and audio
measurement location provided there is no greater than a 5 mile separation
between the data collection points and the measurement locations have similar
characterization, i.e. same side of the mountain ridge, etc.
4. Meteorological measurements of wind speed
and direction shall be collected using anemometers at a 10-meter height (32.8
feet) above the ground. Results shall be reported, based on 1-second
integration intervals, and shall be reported synchronously with hub level and
sound level measurements at 10-minute measurement intervals. The wind speed
average and maximum shall be reported.
5. The sound microphone shall be positioned
at a height of approximately 4 to 5 feet above the ground, and oriented in
accordance with the manufacturer's recommendations.
6. When possible, measurement locations
should be at least 50 feet from any sound source other than the wind energy
development's power generating sources.
(e)
Compliance Data Collection,
Measurement and Retention Procedures
1. Measurements of operational, sound, audio
and meteorological data shall occur as set forth in subsection I(8)(e) (7
through 10).
2. All operational,
sound and meteorological data collected shall be retained by the wind energy
development for a period of 1 year from the date of collection and is subject
to inspection by the Department and submission to the Department upon
request.
3. All audio data
collected shall be retained by the wind energy development for a period of four
weeks from the date of collection unless subject to a complaint filed in
accordance with the complaint protocol approved by the Department and is
subject to inspection by the Department and submission to the Department upon
request. Specific audio data collected that coincides with a complaint filed in
accordance with the approved complaint protocol shall be retained by the wind
energy developer for a period of 1 year from the date of collection and is
subject to inspection by the Department and submission to the Department upon
request.
4. Written notification of
the intent to collect compliance data must be received by the Department prior
to the collection of any sound level data for compliance purposes. The
notification shall state the date and time of the compliance measurement
period.
Note:Notice received
via electronic mail is sufficient regardless of whether it is received during
business hours.
5. Compliance data from the operation of a
wind energy development shall be submitted to the Department, at a minimum:
(a) Once during the first year of facility
operation;
(b) Once during each
successive fifth year thereafter until the facility is
decommissioned;
(c) In response to
a complaint regarding operation of the wind energy development as set forth in
subsection I(7)(j) of the rule and any subsequent enforcement by the
Department; and
(d) For validation
of an applicant's calculated sound levels when requested by the
Department.
6. All sound
level, audio and meteorological data collected during a compliance measurement
period for which the Department has been notified that meets or exceeds the
specified wind speed parameters shall be submitted to the Department for review
and approval. All data submittals shall be submitted to the Department within
30 days of notification of intent to collect compliance data.
7. Measurement shall be obtained during
weather conditions when the wind turbine sound is most clearly noticeable,
generally when the measurement location is downwind of the wind energy
development and maximum surface wind speeds < 6 miles per hour (mph) with
concurrent turbine hub-elevation wind speeds sufficient to generate the maximum
continuous rated sound power from the nearest wind turbines to the measurement
location. A downwind location is defined as within
450 of the direction between a specific measurement
location and the acoustic center of the five nearest wind turbines.
[Note:These conditions typically occur during
inversion periods usually between 11 pm and 5 am.]
8. In some circumstances, it may not be
feasible to meet the wind speed and operations criteria due to terrain features
or limited elevation change between the wind turbines and monitoring locations.
In these cases, measurement periods are acceptable if the following conditions
are met:
(a) The difference between the
LA90 and LA10 during any
10-minute period is less than 5 dBA; and
(b) The surface wind speed (10 meter height)
(32.8 feet) is 6 mph or less for 80% of the measurement period and does not
exceed 10 mph at any time, or the turbines are shut down during the monitoring
period and the difference in the observed LA50 after
shut down is equal to or greater than 6 dBA; and
(c) Observer logs or recorded sound files
clearly indicate the dominance of wind turbine(s).
9. Measurement intervals affected by
increased biological activities, leaf rustling, traffic, high water flow,
aircraft flyovers or other extraneous ambient noise sources that affect the
ability to demonstrate compliance shall be excluded from all compliance report
data. The intent is to obtain 10-minute measurement intervals that entirely
meet the specific criteria.
10.
Measurements of the wind energy development sound shall be made so as to
exclude the contribution of sound from other development equipment that is
exempt from this regulation.
(f)
Reporting of Compliance Measurement
Data
Compliance Reports shall be submitted to the Department
within 30 days of notification of intent to collect compliance data or upon
request by the Department and shall include, at a minimum, the
following:
1. A narrative description
of the sound from the wind energy development for the compliance measurement
period result;
2. The dates, days
of the week and hours of the day when measurements were made;
3. The wind direction and speed, temperature,
humidity and sky condition;
4.
Identification of all measurement equipment by make, model and serial
number;
5. All meteorological,
sound, windscreen and audio instrumentation specifications and calibrations;
6. All A-weighted equivalent sound
levels for each 10-minute measurement interval;
7. AllLA10and
LA90percentile levels;
8. All 10 minute 1/3 octave band linear
equivalent sound levels (dB);
9.
All short duration repetitive events characterized by event amplitude.
Amplitude is defined as the peak event amplitude minus the average minima sound
level immediately before and after the event, as measured at an interval of 50
milliseconds ("ms") or less, A-weighted and fast time response, i.e. 125 ms.
For each 10-minute measurement interval short duration repetitive sound events
shall be reported by number for each observed amplitude integer above 5
dBA.
10. Audio recording devices
shall be time stamped (hh:mm:ss) and at a minimum 16 bit digital, recording the
sound signal output from the measurement microphone at a minimum sampling rate
of 24 thousand (k) samples per second to be used for identifying events. Audio
recording and compliance data collection shall occur through the same
microphone/sound meter and bear the same time stamp. Should any sound data
collection be observed by a trained attendant, the attendant's notes and
observations may be substituted for the audio files during the compliance
measurement period;
11. All
concurrent time stamped turbine operational data including the date, time and
duration of any noise reduction operation or other interruptions in operations
if present; and
12. All other
information determined necessary by the Department.
