Portland City Code ch. 14

Citation: Portland City Code ch. 14
Parent Document: Portland City Code ch. 14
Jurisdiction: Portland (municipal)
Original Source: https://www.portlandmaine.gov/asset/ae8cabd1-66eb-4a1c-9224-92bbca5e792f ↗

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2b/B-2c, I-B, R-P, O-P, A-B, and IS-FBC zones, seconds or more shall be measured on the
sound shall be measured at lot boundaries. For basis of the energy average sound level over a
any noise generated by a use in the B-3/B-3b/B- period of 60 seconds (LEQ1).
3c, sound shall be measured at lot boundaries E. Wind energy systems
or within publicly accessible pedestrian open 1. Where the underlying zone is residential
space. For any noise generated by a use in the and does not specify sound requirements,
B-4 zone, sound shall be measured off premises or where the system will be within 100 feet
at the source of complaint. of a residential building, the audible sound
C. In addition to the sound level standards levels generated by the wind energy
established in Table 6-G, all uses shall employ system shall not exceed 45 decibels on the
best practicable sound abatement techniques A scale between the hours of 9:00 p.m.
to prevent tonal sounds, or sound waves and 7:00 a.m., and 50 decibels on the A
usually perceived as a hum or whine because scale between 7:00 a.m. and 9:00 p.m., as
their instantaneous sound pressure varies measured at the nearest property line in
essentially as a simple sinusoidal function of accordance with this provision and
time, and impulse sounds, or sound events technical standards set out in the City of
characterized by brief excursions of sound Portland Technical Manual.
pressure, each with a duration of less than one 2. For any system over 45 feet in total height
second. If such tonal and impulse sounds not in the Recreation and Open Space,
cannot be prevented, uses shall employ best Resource Protection, or Island Transfer
practicable sound abatement techniques to Station Overlay Zones, the maximum
minimize the impact of such sounds in sound levels allowed by this ordinance shall
residential zones. not be exceeded at the nearest property
D. Sound levels shall be measured with a sound boundary and at the nearest point
level meter with a frequency weighting network vertically above the property line that
manufactured according to standards coincides with the maximum building
prescribed by the American National Standards height allowed in the abutting zone.
Institute (ANSI) or its successor body. 3. Any system located within the Recreation
Measurements shall be made at all major lot and Open Space, Resource Protection, or
lines of the site, at a height of at least four feet Island Transfer Station Overlay Zones and
above the ground surface. In measuring sound more than 100 feet from a residential
levels under this subsection, sounds with a building shall not exceed 55 decibels on the
continuous duration of less than 60 seconds A scale as measured 50 feet from the base
shall be measured by the maximum reading on of the tower.
a sound level meter set to the A weighted scale 4. Audible sound levels of wind energy
and the fast meter response (L maxfast). systems shall include sounds generated in
Sounds with a continuous duration of 60 all conditions including low and high winds
(furling, yawing, and flutter) and power CITY OF PORTLAND LAND USE CODE | 6-41 USE STANDARDS

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