Fort Walton Beach Council agenda — 01-25-11 special — reading text

drafting the ordinance to ensure that the means employed for its enforcement are r not unduly oppressive and that the restrictions placed upon the unwanted noise are not beyond those necessary to accomplish the purpose of the ordinance. 1. 7. Qualitative vs. Quantitative Noise Ordinances Local noise ordinances have typically included broad noise prohibitions such as the following: The creation ... of any unreasonable, unnecessary or excessive noise which results in the disturbance of the public peace and welfare 21and complaints to local government agencies is hereby prohibited and shall constitute disorderly conduct. This type of ordinance is based upon vague standards that proscribe noise characterized by one or more adjectives, such as " unusual ", " unnecessary ", or " unreasonable ". The ordinance may also define certain sound related 22 activities or specific noise sources to be annoying or disturbing and thus violative of the ordinance. Such ordinances are commonly referred to as qualitative, because they define the prohibited 23 noise by its " character or nature ". In the past, noise control ordinances universally took this form. Such ordinances may also prohibit certain activities, restrict activities to certain hours of the day, require 24 permits or licenses for noisy activities or create quiet zones in which certain activities are prohibited. The qualitative ordinance is generally subjective in nature, and is more likely to pose constitutional issues such as vagueness, and is also more likely to be subject to enforcement at the discretion of local police and to non -uniform application as indicated above. Many noise control ordinances fail to include quantitative acoustical criteria, and merely prohibit " loud noise ". Quantitative ordinances, on the other hand, proscribe noise -producing conduct by amount, applying scientific standards of sound intensity and frequency. The quantitative ordinance is capable of providing non -discretionary, objective and predictable standards. Quantitative standards are more amendable to tailoring in order to meet the specific, unique needs of a local community. As stated previously, a determination must be made in a given community as to how much quiet or lack of noise the community seeks. One approach to making this determination can include the following steps: 1) observe the way communities react to known noise conditions; 2) supplement this data by obtaining answers 25 to carefully worded questionnaires; 3) use this information in developing appropriate noise restrictions. dBA26 Maximum noise levels are generally expressed in and vary considerably from ordinance to ordinance, ranging from 40 dBA ( Beverly Hills, CA) to 60 dBA ( cities).? The ordinance may specify varying dBA levels for different areas of the community, as appropriate. The table attached as Exhibit A" shows decibel ranges that are generally compatible with the different land use categories specified2 -. In addition, the World Health Organization-' has published draft recommended guideline noise levels for protection against unwanted noise. These noise levels are designed to prevent sleep disturbance, annoyance, and speech interference. The levels are based upon results from numerous studies in laboratories and field surveys. The levels are as follows: as c To protect the majority from being moderately annoyed, the noise level should not exceed 50 dBA. c L To protect the majority of people from being seriously annoyed during the daytime, the level 0 a from steady continuous noise in outdoor living areas should not exceed 55 dBA. At night, outdoor levels should not exceed 45 dBA, so that the recommended level of 30 dBA o 30 z inside bedrooms for steady state continuous noise can be met with the windows open. o T r The above 31 stated levels are in accord with the comfort values which were recommended by the EPA in 1974. 1. 8 Establishing and Measuring Noise Levels When determining appropriate noise emission levels, it is also important to outline the conditions under which they must be verified, including: 1) the reference time intervals; and 2) the location at which the noise emission is measured ( determine whether the emission level will be measured near the wall of a building or in an open field; the difference amounts to 3 dBA).32 The field of study of acoustics has provided scientifically accepted standards for the identification and measurement of a noise. By using this scientific expertise, a local community can develop an effective 33 and meaningful noise regulation by enacting an objective, quantitative ordinance. Sound is produced by any vibrating body. The sensation of sound is caused by stimulation of the auditory nerve of the ear by sound waves produced by the vibrating body. In order to give meaning to the system used to measure sound ( decibels), acoustical measurements use a reference level. The reference level for sound pressure is 0.0002 microbar. A microbar is a pressure of 1 dyne /cm2 or approximately one - millionth of normal atmospheric pressure ( 1, 013, 250 microbars). A sound pressure level of 0. 0002 microbar is approximately the weakest sound that can be heard by a person with very good hearing. This quantity represents the threshold of audibility and is also equal to zero decibels, the lowest point of the decibel scale of noise levels. The range of the decibel scale is from zero, at which the human ear receives little or no sensation, even though 34some energy may be present, to approximately 120 decibels, where the sound becomes extremely intense. Intensity and frequency are the two significant properties of sound. Frequency is the number of complete fluctuations per second of the sound wave, and intensity ( or loudness) is the magnitude of the fluctuation measured in atmospheric pressure units or microbars. Measurements of the frequency and intensity of sound as they apply to noises in the community can be quantified using a sound -level meter. The readings are measured using the decibel scale. " Weighting" systems built into all standard sound -level meters can account for the fact that different sound frequencies affect the listener's perception of loudness. The weighting of decibel levels is done through the application of electrical filtering mechanisms. The A-  A.1. a 15 weighting scale is most often used for measuring the level of noise in local communities. The A- weighted decibel scale, expressed as " dBA ", is designed to correct decibel readings to account for the fact that the human ear is less sensitive to low pitched sounds than it is to high pitched sounds. The A- 36 weighted scale provides a better measure of the subjective response of a human to any given noise. In order to measure noise in the field effectively ambient noise levels must be accounted for. Ambient noise is defined as the surrounding or steady background noise, as distinguished from the specific noise which is the subject of the attempted measurement. When a measurement is made with a sound level meter, it is difficult to isolate the ambient noise from the subject noise, and the measurement of the subject noise is thereby affected. Solutions to the ambient noise measurement problem include: 1) establishing maximum noise levels for fixed delineated areas within the community, which are related to particular zoning classifications and time periods; 2) including in the ordinance's definition of "ambient noise level" a provision for on -site c=c determination; and 3) establishing quantitative noise levels in relation to the ambient noise level ( i.e. 115 dBA above ambient "). The ambient noise level can be determined by taking sound level readings with the 0 offending sound silenced. If this is not possible, most sounds can be specifically identified through the use of different types of field tests. Also, although 37 difficult and expensive, it is scientifically possible to ' o z identify any sound through spectrum analysis. CD T Ir- 1. 9 Specific Provisions of a Noise Control Ordinance The provisions of an ordinance should be as precise, simple and clear as possible to make them comprehensible to the public and to improve their amenability to enforcement by authorities. 1. 9. 1. General Prohibitions This section of the ordinance should generally define prohibited acts to include making excessive noise or creating a noise disturbance. 1. 9. 2. Definitions At a minimum, the following terms must be defined: 1. 9. 2. 1The unit of measure to be employed to determine proscribed noise levels such as " A- weighted sound pressure level" ( see footnote 19); 1. 9. 2. 2 "Noise" is usually defined as any sound which annoys or disturbs humans or is unwanted or which causes or tends to cause an adverse psychological effect on human beings. 1. 9. 2. 3 " Noise disturbance" is defined to include any sound which endangers or injures the health of humans or disturbs a reasonable person of normal sensitivities. 1. 9. 3. Specific Prohibitions Specific prohibited acts should include the use or maintenance of the following items or activities