In this chapter, the following terms have the meanings indicated. Terms Defined. “ANSI” means American National Standards Institute or its successor bodies. “Construction” means any site preparation, assembly, erection, repair, alteration, or similar activity. “Curtilage” means the enclosed land surrounding a house or dwelling and includes all areas maintained in lawn or horticultural plantings and may be bounded by a fence or wall, but would not typically include areas more distant than 300 feet from the dwelling unless those areas were horticulturally maintained and routinely used as areas of personal refuge, or supported accessory structures that were routinely utilized. “Daytime hours” means 7 a.m. to 10 p.m., local time. “dBA” means abbreviation for the sound level in decibels determined by the A-weighting network of a sound level meter or by calculation from octave band or one-third octave band data. “Decibel (dB)” means a unit of measure equal to ten times the logarithm to the base ten of the ratio of the square of the sound pressure to the square of a standard reference pressure. For the purpose of this subtitle, 20 micropascals shall be the standard reference pressure. “Demolition” means any dismantling, destruction, or removal activities. “Department” means the Department of the Environment. “Emergency” means any occurrence or set of circumstances involving actual or imminent physical trauma or property damage which demands immediate action. “Environmental noise” means the noise that exists at any location from all sources. “Environmental noise standards” means the goals for environmental noise, the attainment and maintenance of which, in defined areas and under specific conditions, are necessary to protect the public health and general welfare. “Equivalent sound level” (also “average sound level”) means the level of a constant sound which, in a given situation and time period, would convey the same sound energy as does the actual time-varying sound during the same period. Equivalent sound level is the level of the time weighted, mean-square, A-weighted sound pressure. A numerical subscript may be used to indicate the time period under consideration; i.e., Leq24 or Leq8 for 24-hour and 8-hour periods, respectively. No subscript indicates a 24-hour period. The mathematical expression for the Leq is as follows: “IEC” means International Electrotechnical Commission. “Nighttime hours” means 10 p.m. to 7 a.m., local time. “Noise” means the intensity, frequency, duration, and character of sound, including sound and vibration of sub-audible frequencies. “Noise pollution” means the presence of noise of sufficient loudness, character, and duration, which whether from a single source or multiple sources, is, or may be predicted with reasonable certainty to be, injurious to health or which unreasonably interferes with the proper enjoyment of property or with any lawful business or activity. “Periodic noise” means noise possessing a repetitive on-and-off characteristic with a rapid rise to maximum and a short decay not exceeding 2 seconds. “Person” means any individual, group of individuals, firm, partnership, voluntary association, or private, public, or municipal corporation, or political subdivision of the State, or department, bureau, agency, or instrument of federal, State, or local government, responsible for the use of property. “Prominent discrete tone” means any sound which can be distinctly heard as a single pitch or a set of single pitches. For the purposes of this regulation, a prominent discrete tone shall exist if the one-third octave band sound pressure level in the band with the tone exceeds the arithmetic average of the sound pressure levels of the 2 contiguous one-third octave bands by 5 dB for center frequencies of 500 Hz and above and by 8 dB for center frequencies between 160 and 400 Hz and by 15 dB for center frequencies less than or equal to 125 Hz. “Sound level” means, in decibels, the weighted sound pressure level measured by the use of a sound level meter. Sound level and noise level are synonymous. The weighting employed shall always be specified. “Sound level meter” means an instrument, meeting International Electrotechnical Commission and American National Standards Institute standards comprising a microphone, an amplifier, an output meter, and frequency weighting network(s) that is used for the measurement of sound pressure levels in a specified manner. Sound Pressure. “Sound pressure” means the minute fluctuations in atmospheric pressure which accompany the passage of a sound wave. Sound pressure is usually measured in dynes per square centimeter (dyne/cm2), or in newtons per square meter (N/m2), or in micropascals. “Sound pressure level” means, in decibels, 20 times the logarithm to the base ten of the ratio of a sound pressure to the reference sound pressure of 20 micropascals (20 micronewtons per square meter). In the absence of any modifier, the pressure is understood to be that of a root mean-square pressure. “Source” means any person or property, real or personal, contributing to noise pollution. “Vibration” means any oscillatory motion of solid bodies. “Zoning district” means a general land use category, defined according to local subdivision, the activities and uses for which are generally uniform throughout the subdivision. For the purposes of this regulation, property which is not zoned “industrial”, “commercial”, or “residential” shall be classified according to use as follows: “Industrial” means property used for manufacturing and storing goods; “Commercial” means property used for buying and selling goods and services; “Residential” means property used for dwellings.