San Anselmo Municipal Code Art. 1 General Provisions

It shall be the policy of the Town to prohibit unnecessary, excessive, and annoying noises from all sources. At certain levels noises are detrimental to the health, safety, and welfare of the citizenry and in the public interest should be systematically proscribed.

(Ord. 685, eff. March 13, 1975)

Unless the context otherwise clearly indicates, certain words and phrases used in this article are defined as follows:

(a) "Noise level" shall mean the sound level in decibels dBA measured on the A-weighted scale as defined by the American National Standard Institute specifications S1.4-1971 or the most recent revision thereof.

(b) "Sound measurement". The sound meter shall be set for slow response speed, except that for impulse noises peak measuring instruments shall be used. Prior to each measurement the meter and the microphone shall be verified and adjusted to a +/- 0.3 decibel by means of an acoustical calibrator. For outside measurements the microphone shall be not less than four (4′) feet above the ground, at least four and one-half (4½′) feet distant from walls or similar large reflecting surfaces, and shall be protected from the effects of wind noises and other extraneous sounds by the use of screens, shields, or other appropriate devices. For inside measurements the microphone shall be at least three (3′) feet distant from any wall, and the average sound measurement shall be determined from a minimum of three (3) microphone positions throughout the room.

(c) "Ambient noise" shall mean the all-encompassing noise associated with a given environment, being a composite of sounds from many sources near and far. The ambient noise level shall mean that residual sound averaged over a fifteen (15) minute interval which excludes random or intermittent noises and the alleged offensive noise measured at the location and time of day at which a comparison with an alleged offensive noise is to be made.

(d) "Decibel" shall mean a unit for measuring the relative loudness of sounds equal approximately to the smallest degree of difference of loudness ordinarily detectable by the human ear whose range includes approximately 130 decibels on a scale beginning with one for the faintest audible sound.

(e) "Emergency work" shall mean work made necessary to restore property to a safe condition following a public calamity or work required to protect persons or property from an imminent exposure to danger or work by private or public utilities when restoring utility service.

(f) "Person" shall mean a person, firm, association, partnership, joint venture, corporation, or any entity, public or private.

(g) "Sound level meter" shall mean an instrument, including a microphone and amplifier, an output meter, and frequency weighting networks for the measurement of sound levels, which satisfies the pertinent requirements in American National Standard Institute specifications for sound level meters S1.4-1971 or the most recent revision thereof.

(h) "Motor-driven vehicles" shall mean and include any vehicle driven by an electric, propane, or gasoline motor, including automobiles, motorcycles, motor-driven cycles, mini-bikes, go-carts, and trucks.

(i) "Sound amplifying equipment" shall mean any machine or device for the amplification of the human voice, music, or other sound. "Sound amplifying equipment" shall not include standard automobile radios when used and heard only by the occupants of the vehicle in which the automobile radio is installed and shall not include radios or warning devices on any authorized emergency vehicle used in compliance with State or Federal laws for emergency or traffic safety purposes.

(j) "Sound truck" shall mean any motor vehicle or any other vehicle, regardless of motive power, whether in motion or stationary, having mounted thereon, or attached thereto, any sound amplifying equipment.

(k) "Commercial purpose" shall mean the use, operation, or maintenance of any sound amplifying equipment for the purpose of advertising any business or any goods or any services or for the purpose of attracting the attention of the public to, or advertising for, or soliciting patronage or customers to or from any performance, show, entertainment, exhibition, or event or for the purpose of demonstrating such sound equipment.

(l) "Noncommercial purpose" shall mean the use, operation, or maintenance of any sound equipment for other than a commercial purpose and shall include, but not be limited to, philanthropic, religious, political, patriotic, or charitable purposes.

(m) "Property plane" shall mean the vertical line through the property line which determines the property boundaries in space.

(Ord. 685, eff. March 13, 1975)

Except as otherwise provided in Section 4-7.105 of this article, any sound level measurement made pursuant to the provisions of this chapter shall be measured with a sound level meter using the A weighting.

(Ord. 685, eff. March 13, 1975)

(a) In the Single-Family Residential District (R-l), Two-Family Residential District (R-2), and Neighborhood Apartment District (R-3) on or before September 13, 1975, and in all commercial districts (C-1, C-2, C-3, and CM) on or before March 13, 1976, unless otherwise provided, it shall be unlawful for any person to operate any machinery or equipment, pump, fan, air-conditioning apparatus, or similar mechanical device or any radio receiving set, musical instrument, phonograph, television set, or other similar device in any manner so as to create any noise which would cause the noise level at the property plane of the property from which the noise is emitted to exceed the following values:

Table 1

(b) For the purposes of this section, "noise level" shall mean measured sound level with the following values, dBA, added as corrections for the time duration and character of the noise:

(c) When noise is emitted from property bordering any other zoning district, the lesser allowable noise level shall be applicable.

(d) The provisions of subsection (a) of this section shall not apply to any burglar alarm or other emergency signalling device; nor to any standby machinery or equipment necessarily operated in emergency situations; provided, however, such standby machinery or equipment shall not at any time emit noise exceeding a level of seventy (70) dBA as measured at the property plane of the property from which the noise is being emitted.

(Ord. 685, eff. March 13, 1975)

(a) When an objectionable noise is clearly audible, but where the ambient noise level does not permit quantitative measurement by the sound level meter using the A weighting, the sound measurement shall be performed utilizing an octave band sound analyzer.

(b) The following table sets forth the octave band noise limits corresponding to the Sound Level A limits set forth in Section 4-7.104 of this article and shall be utilized as provided for in subsection (a) of this section in determining whether a violation exists:

Octave Band Sound Pressure Level, dB re .0002 dyne/cm 2 Octave Band Center Frequency in Hz

(c) The correction factors set forth in subsection (b) of Section 4-7.104 of this article shall be applicable to measurements taken by an octave band sound analyzer.

(Ord. 685, eff. March 13, 1975)