(a) Purpose and intent. The City Council finds that exposure to excessive noise is injurious to the public health, safety and welfare, interferes with the quiet enjoyment of life and property, and interferes with the tranquility and privacy of the home.
(b) Definitions.
ANNUAL CONTOUR MAP. The map of noise contours developed annually by the Metropolitan Airports Commission and published in the Minneapolis St. Paul International Airport Annual Noise Contour Report.
DAY-NIGHT AVERAGE SOUND LEVEL, DNL. The average sound level, in decibels, for a 24 hour period, obtained after the addition of 10 decibels (dB) to sound levels for the period between 10 p.m. and 7:00 a.m.
FUTURE CONTOUR MAP. The noise forecast for the most distant year included in the most recent comprehensive plan or environmental document adopted for Minneapolis-St. Paul International Airport by the Metropolitan Airport Commission.
NEW CONSTRUCTION. All newly constructed enclosed structures including additions, alterations, and reconstruction of existing structures.
(c) State regulation. New Construction or changes in use must comply with Minnesota Rules 7030.0010-0080, as the Rules may be amended from time to time.
(d) Airplane noise attenuation.
(1) Applicability. All new construction or change in use located at or above the 60 dB DNL Contour must meet the standards of this section. The area at or above the 60 dB DNL Contour is determined by combining all areas within the 60 dB DNL noise exposure area on the Annual Contour Map with all areas forecast to have noise levels at or above 60 dB DNL on the Future Contour Map at the time an application is made to the city.
(A) Interior noise performance standard. New residential, place of assembly, hospital, hotel, or educational construction or uses must demonstrate building construction will yield an average interior sound level of 45 dBA or less with windows closed for living or sleeping areas or parts of schools that are used for educational instruction.
(B) Compliance. Projects located at or above the 60 dB DNL Contour must include installation of central air conditioning and mechanical ventilation throughout the habitable areas of the structure and must demonstrate compliance with the interior noise performance standard by either performing an acoustical analysis by a certified sound specialist to demonstrate the proposed building will meet the performance standard or apply the materials standards set forward in the following table.
Use | Location (Higher of Annual Contour Map or Future Contour Map) | Desired Noise Level Reduction | Roof- Ceiling* | Walls* | Exterior Windows* | Exterior Doors* |
Residential, Places of Assembly, Hospital, Educational, Hotel | 60-64 dB DNL | 20 dBA | 40 STC | 40 STC | 30 STC | 20 STC |
65-69 dB DNL | 25 dBA | 45 STC | 45 STC | 35 STC | 25 STC | |
70 dB DNL and Above | 30 dBA | 50 STC | 50 STC | 40 STC | 30 STC |
* The STC laboratory test of construction materials and assemblies must be conducted according to requirements of the American Society of Testing and Materials (ASTM E90 or ASTM E413)
(e) Outdoor mechanical equipment.
(1) Applicability. The standards of this subsection apply to commercial grade mechanical equipment and similar noise sources including, but not limited to, generators, ventilation equipment or air heating or cooling equipment, commercial laundry appliances, and carwash equipment.
(2) Noise impact statements associated with outdoor mechanical equipment may be required in accordance with § 10.29.04.
(3) Standard. When required, noise impact statements that analyze the operation of proposed outdoor mechanical equipment and similar noise sources including, but not limited to, generators, ventilation equipment or air heating or cooling equipment, commercial laundry appliances, and carwash equipment must identify the code compliant location(s) of said equipment that is least impactful to nearby residential uses.
(A) Placement. Equipment must be situated in the location that is least impactful to nearby residential uses, as determined in the noise impact statement.
(B) Alternatives. At its discretion, the approving body may allow outdoor equipment at other code compliant locations when information is provided that addresses the following:
(i) The viability of code complying alternative locations for the outdoor mechanical equipment;
(ii) The impacts of the outdoor mechanical equipment at the proposed location relative to the impacts of the outdoor mechanical equipment at a code complying alternative location;
(iii) The extent to which the proposed equipment is the lowest impact design available;
(iv) The extent to which mitigation is provided to minimize impacts.