Ord 232 Aircraft Noise AttenuationCodified As Ordinance #1509
CITY OF MENDOTA HEIGHTS
DAKOTA COUNTY, MINNESOTA
ORDINANCE NO' 232-
ORDINANCE FOR AIRCRAFT NOISE ATTENUATION
An Ordinance promoting the health, safety and
general welfare of the citizens of Mendota Heights, Minnesota,
requiring compliance with noise reduction standards
in building construction.
SECTION 1. Statutory Authority
This ordinance is adopted pursuant to M.S. Chapter 155, 473.192.
SECTION 2. Findings of Fact
The City of Mendota Heights finds that development within certain areas
of the City is impacted by aircraft noise; that said noise is beyond the
regulatory authority of the City to control; that certain uses of land are
inappropriate in areas of high aircraft noise; that some structures do not
adequately attenuate aircraft nose resulting in negative impacts on the
health, safety and welfare of the residents or inhabitants of the
structures; that, through proper construction methods, the means exist to
attenuate aircraft noise to interior levels which alleviate such negative
impacts; and that the requirements of this ordinance are necessary to
promote and preserve the health, safety and welfare of the citizens of
Mendota Heights.
SECTION 3. Purpose
The purpose of this Ordinance is to require that new or redeveloped
portions of buildings within the City of Mendota Heights be constructed with
materials and in such a manner that aircraft noise is attenuated by the
structure to an interior level which has no adverse impact on the health,
safety and general welfare of the residents, all in accordance with the
Metropolitan Council's Guidelines for Land Use Compatibility with Aircraft
Noise. This ordinance shall not apply to remodeling or rehabilitating an
existing residential building, nor to the construction of an appurtenance to
an existing residential building.
SECTION 4. Definitions
For purposes of this ordinance, the terms defined in this section have
the meanings given them in this section.
AIRCRAFT NOISE ZONE. Aircraft Noise Zone means any one of the four zones
identified on the map attached hereto as Appendix A and incorporated herein.
CONSISTENT: Land uses that are acceptable.
dBA. dBA means a unit of sound pressure level weighted by use of the A
metering characteristics and weighting as specified in the American National
Standards Institute Specification for Sound Level Meters (ANSI 51.4-1983),
which is hereby incorporated by reference. dBA is also referred to as an A-
weighted decibel.
INCONSISTENT: Land uses that are not acceptable even if acoustical
treatment were incorporated in the structure.
IIINFILL DEVELOPMENT" pertains to an undeveloped parcel or parcels of land
proposed for development similar to or less noise-sensitive than the
developed parcels surrounding the undeveloped parcel (for example, a new
house on a vacant lot in a residential neighborhood, or a new industry on a
vacant parcel in an established industrial area).
Leq. Leq means the equivalent continuous sound level which over the period
of one hour has the same A-weighted sound energy as the time varying sound.
L dn. Ldn means the day-night average level, or the 24-hour equivalent
continuous sound level (time-averaged A-weighted sound level) from midnight
to midnight, obtained after the addition of 10 dBA to sound levels measured
from 10 p.m. to 7 a.m.
"MAJOR REDEVELOPMENT" means a relatively large parcel of land with all
structures proposed for extensive rehabilitation or demolition, and
different uses (for example, demolition of a square block of old office and
hotel buildings for new housing, office, commercial uses; conversion of
warehouse to office and commercial uses).
"NEW DEVELOPMENT" means a relatively large, undeveloped tract of land
proposed for development (for example, a residential subdivision, industrial
park or shopping center).
NOISE REDUCTION LEVEL. Noise reduction level means the difference between
the exterior and interior sound level, expressed in dBA, which is achieved
by the intervening structure.
RECOGNIZED ACOUSTICAL SPECIALIST. A recognized acoustical specialist means
a person qualified by education and experience to conduct sound analysis of
buildings and approved for such purpose by the City. The approved
individual shall have at least three years of experience in the field of
sound control; a degree from a recognized institute of higher learning in
the process of sound analysis of buildings.
"RECONSTRUCTION OR ADDITIONS TO EXISTING STRUCTURES" pertains to replacing a
structure destroyed by fire, age, etc., to accommodate the same use that
existed before destruction, or expanding a structure to accommodate
increased demand for existing use, but does not pertain to remodeling or
rehabilitating existing residential buildings nor to the construction of an
appurtenance to an existing residential building.
SOUND. Sound means energy that is transmitted by pressure waves in the air
or in other materials and is the objective cause of the sensation of
hearing. It is commonly called noise if it is unwanted.
SOUND ATTENUATION. Sound attenuation means the reduction in sound level
which occurs between the source and receiver.
SOUND LEAK. Sound leak means an opening in a structure through which sound
can pass. Sound leaks are often extremely small holes or cracks. In
general, an air leak is a sound leal.
SOUND LEVEL. Sound level means the level of sound pressure measured with a
sound level meter and one of its weighting (frequency) networks. When A-
weighting is used, the sound level is expressed as dBA.
SOUND TRANSMISSION CLASS (STC). Sound transmission class means a single-
number rating for describing the degree of sound transmission loss specified
for a wall, window, partition or other building element. The higher the
STC, the more attenuation the building element will afford.
SECTION 5. Scope and Effect
The Aircraft Noise Zones established by this Ordinance shall overlay
the zoning districts established by Ordinance No. 401, adopted April 3,
1962, so that any parcel of land lying in an overlay zone shall also lie on
one or more of the established zoning districts. Territory within a given
overlay zone shall be subject to the requirements established by the other
applicable ordinances and regulations of the City. Within each adopted
overlay zone, all uses shall be permitted in accordance with the regulations
for the underlying zoning districts, provided, however, that the appropriate
building permit is first obtained, and provided further that no use
designated as inconsistent on the Noise Compatibility Tables, attached
hereto as Appendix B and incorporated herein, shall be permitted. This
Ordinance applies to all construction and any reconstructed portion of a
building requiring a building permit after the effective date of this
Ordinance except remodeling or rehabilitation of an existing residential
building or the construction of an appurtenance to an existing residential
building.
SECTION 6. Prerequisites to Issuance of Building or Occupancy Permit
Any application for a City of Mendota Heights building or occupancy
permit pertaining to land located in an Aircraft Noise Zone must demonstrate
compliance with the provisions of this Ordinance prior to the issuance of
such permit.
SECTION 7. Establishment of Zones
The following Aircraft Noise Zones are hereby established as part of
the Zoning Ordinance of the City of Mendota Heights.
Aircraft Noise Zone I
Aircraft Noise Zone II
Aircraft Noise Zone III
Aircraft Noise Zone IV
The boundaries of the Aircraft Noise zones are as delineated on the diagram
attached hereto as Appendix A and incorporated herein.
SECTION 8. Noise Compatibility Tables
All construction or reconstruction requiring a building permit and
located within an Aircraft Noise Zone shall be constructed in such a way
that the applicable noise level reduction requirements contained in the
Noise Compatibility Tables (Appendix B) are met or exceeded. Where a
particular structure contains different land uses, the more stringent
requirements of the applicable table shall apply, except where it is
architecturally possible to achieve the appropriate noise reduction level
for each different use, and the uses are acoustically separated by a wall or
partition with a minimum STC of 25.
SECTION 9. Enforcement
The provisions of this Ordinance shall be enforced pursuant to Sections
10 and 11.
SECTION 10. Plans and Specifications
A. All applicants for a building or occupancy permit shall include with the
application all plans, specifications or other information required by
this Ordinance. The plans and specifications shall describe in
sufficient detail all pertinent features of the building, building
materials, heating and ventilation systems, including but not limited to
the STC ratings of exterior roof/ceilings, walls, windows, and doors;
and other pertinent data as may be requested by the City to indicate
conformance with the applicable noise reduction level requirements as
specified in the Noise Compatibility Tables. To assure the elimination
of sound leaks, the plans and specifications shall demonstrate
compliance with the following standards.
1. A mechanical ventilation system shall be installed that will provide
the minimum air circulation and fresh air supply requirements as
provided in the State and Uniform Building Code for the proposed
occupancy without the need to open any exterior doors or windows.
2. The perimeter of all exterior windows and door frames shall be
sealed airtight to the exterior wall construction.
3. Fireplaces shall be equipped with well-fitted chimney closing
devices.
4. All ventilation ducts, except range hoods, connecting interior space
to outdoors shall be provided with a bend such that no direct line
of sight exists from exterior to interior through the vent duct.
5. Doors and windows shall be constructed so that they are close-
fitting. Weatherstripping seals shall be incorporated to eliminate
all edge gaps.
6. All penetrations through exterior walls by pipes, ducts, conduits
and the like shall be caulked airtight to the exterior construction.
The City may require that plans and specifications be certified by a
Recognized Acoustical Specialist for compliance with this ordinance.
B. Within 30 days of receipt of appropriate plans and specifications, the
City shall approve or reject the plans based upon the ability of the
proposed materials and construction techniques to adequately attenuate
noise. The City shall approve the plans and specifications if:
1. The plans and specifications adequately document the use of
construction assemblies that meet or exceed the STC ratings
required by the following table:
STC RATINGS REQUIRED FOR EXTERIOR BUILDING ELEMENTS
SPECIFIED NOISE
LEVEL REDUCTION
REQUIRED
STC RATING
NEEDED FOR COMPLIANCE*
dBA
Roof/Ceiling
Walls
Windows
Doors
20
40
40
30
20
25
45
45
35
25
30
50
50
40
30
35
55
55
45
35
40
60
60
50
40
*All values +/- 2 STC. The STC laboratory test of construction materials
and assemblies must be conducted according to the requirements of the
American Society for Testing and Materials (ASTM E90 or ASTM E 336); or
2. The plans and specifications have been certified by a Recognized
Acoustical Specialist as achieving the interior noise level
reduction required by the applicable portion of the Noise
Compatibility Table.
In the event that the drawings are rejected, the reasons for such
rejection shall be submitted to the applicant in writing. No construction
shall occur prior to the approval of the appropriate plans and
specifications. All construction shall be performed in accordance with the
approved plans and specifications as determined by the City shall be deemed
to meet the noise attenuation requirements of this Ordinance.
SECTION 11. Inspections
A. All construction or work for which a building permit is required shall
be subject to inspections by the City. Inspections of noise attenuation
work shall be performed during the required building construction
inspections specified by the City of Mendota Heights code.
B. Field Testing. When inspection indicates that the construction is not
in accordance with the approved plans, the City may order such
corrective action as may be necessary to meet the noise attenuation
requirements of this ordinance. In lieu of performing such corrective
action, a building owner may submit a test report based upon field tests
showing compliance with the noise reduction level requirements contained
in the applicable Noise Compatibility Table. The field test shall be
performed in accordance with the American Society for Testing Materials
Standard E 336-84, Part A1.2.2. outside to Inside (Level Reduction).
SECTION 12. Severability
If any part of this ordinance is held to be unconstitutional or
otherwise illegal, the remainder of this Ordinance shall remain in force and
effect as if such unenforceable provision had not been included herein.
NOISE COMPATIBILITY TABLE 1
Noise Reduction Level in dBA Required to Meet Standards For
Use IN NEW DEVELOPMENT AND MAJOR REDEVELOPMENT
(The Noise Reduction Level numbers specify for each type of land use the
i ) for the use to be
amount of interior sound level reduction necessary
compatible in the applicable Aircraft Noise Zone).
LAND USE TYPE AIRCRAFT
NOISE ZONE
I II III IV
Leq(80+) (75-80) (70-75) (65-70)
Residential
Single/multiplex with individual entrance INCO INCO INCO 25
Multiplex/apartment with shared entrance 1 INCO 35 30 25
Mobile Home INCO INCO INCO 25
Educational and Medical
Schools, churches, hospitals, nursing homes INCO INCO INCO 25
Cultural, Entertainment, Recreational 35 30 25 20
Office, Commercial Retail 35 30 25 CNST
Services
Transportation-passenger facilities
35
30
25
CNST
Transient Lodging
INCO
30
25
20
Other medical, health & educational services 35
30
25
CNST
Other services
35
30
25
CNST
Industrial, Communication, utility
25
CNST
CNST
CNST
Agricultural Land, Water Area,
Resource Extraction
CNST
CNST
CNST
CNST
1 These uses do not permit "in the wall"
air-conditioning units
in
Zones I, II, and III.
NOISE COMPATIBILITY TABLE 2
Noise Reduction Level in dBA to Meet Standard for Use In
INFILL DEVELOPMENT AND RECONSTRUCTION OR ADDITIONS TO EXISTING STRUCTURES
(The Noise Reduction Level numbers specify for each type of land use the
amount of interior sound level reduction necessary for the use to be
compatible in the applicable Aircraft Noise Zone).
LAND USE TYPE AIRCRAFT
NOISE ZONE
Services
Transportation-passenger facilities
I
II
III
IV
Leq
(80+)
(75-80)
(70-75)
(65-70)
Residential
35
30
25
CNST
Single/multiplex with individual entrance 2
40
35
30
25
Multiplex/apartment with shared entrance 2
40
35
30
25
Mobile Home 2
40
35
30
25
Educational and Medical
Schools, churches, hospitals, nursing homes
40
35
30
25
Cultural, Entertainment, Recreational
35
30
25
20
Office, Commercial Retail
35
30
25
CNST
Services
Transportation-passenger facilities
35
30
25
CNST
Transient Lodging
35
30
25
20
Other medical, health & educational svcs.
35
30
25
CNST
Other services
35
30
25
CNST
Industrial, Communication, Utility
25
CNST
CNST
CNST
Aaricultural Land, Water Area
Resource Extraction CNST CNST CNST CNST
1 Does not apply to remodeling or rehabilitation of existing residential
structures, or to construction of appurtenances to existing residential
structures.
2 These uses do not permit "in the wall" air-conditioning units in zones
and III.
SECTION 14. This Ordinance shall be in full force and effect from and after
its publication according to law.
Adopted and ordained into an Ordinance this nineteenth day of May, 1987.
CITY COUNCIL
CITY OF MENDOTA HEIGHTS
13Y a--Ilz �
Charles E. Mertensotto
Mayor
F.W00mv
Kdthleen M. Swanson
i�lty Clerk