Dearborn, MI Noise from Specific Sources: HVAC & Mechanical Noise (2026)

Fixed noise source means a stationary device which creates sounds while fixed or motionless, including but not limited to, residential, agricultural, industrial and commercial machinery and equipment, pumps, fans, compressors, air conditioners, and refrigeration equipment. Impulsive noise means sound of short duration, usually less than one second, with an abrupt onset and rapid decay. Examples of sources of impulsive sound include explosions, drop forge impacts, and the discharge of firearms. Industrial area means as the term is defined in the zoning ordinance of the city. Intermittent noise means any noise which goes on and off during a course of measurement of at least five minutes, but which exceeds ten seconds in duration each time it is on. Intrusive noise means that noise which intrudes over and above the existing ambient noise at a given location. The relative intrusiveness of a sound depends upon its amplitude, duration, frequency and time of occurrence, and tonal or informational contents as well as the prevailing ambient noise level. Mobile noise source means any noise source other than a fixed noise source. Nighttime , except when indicated otherwise, shall mean 10:00 p.m. to 7:00 a.m. Perpetual noise means any noise whose level varies less than 3 dB(A) during a period of at least 30 minutes. Real property boundary means an imaginary line along the ground surface, and