Los Angeles Municipal Code Art. 1 General Provisions

Section 111.00 Declaration of Policy. 111.01 Definitions. 111.02 Sound Level Measurement Procedure and Criteria. 111.03 Minimum Ambient Noise Level. 111.04 Violations: Additional Remedies, Injunctions. 111.05 Enforcement, Citations.

It is hereby declared to be the policy of the City to prohibit unnecessary, excessive and annoying noises from all sources subject to its police power. At certain levels noises are detrimental to the health and welfare of the citizenry and in the public interests shall be systematically proscribed.

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

(a) “Ambient Noise” is the composite of noise from all sources near and far in a given environment, exclusive of occasional and transient intrusive noise sources and of the particular noise source or sources to

be measured. Ambient noise shall be averaged over a period of at least 15 minutes at a location and time of day comparable to that during which the measurement is taken of the particular noise source being measured. (Amended by Ord. No. 156,363, Eff. 3/29/82.)

(b) “Commercial Purpose” is the use, operation, or maintenance of any sound amplifying equipment for the purpose of advertising any business, goods, or services, or for the purpose of attracting the attention

of the public to, advertising for, or soliciting patronage or customers to or for any performance, show, entertainment, exhibition, or event, or for the purpose of demonstrating such sound equipment. (Amended by Ord. No. 156,363, Eff. 3/29/82.)

(c) “Decibel” (dB) is a unit of level which denotes the ratio between two (2) quantities which are proportional to power; the number of decibels corresponding to the ratio of two (2) amounts of power is ten (10)

times the logarithm to the base (10) of this ratio. (Amended by Ord. No. 156,363, Eff. 3/29/82.)

(d) “Emergency Work” is 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. (Amended by Ord. No. 156,363, Eff. 3/29/82.)

(e) “Impulsive Sound” is sound of short duration, usually less than one second, with an abrupt onset and rapid decay. By way of example “impulsive sound” shall include, but shall not be limited to, explosions,

musical base drum beats, or the discharge of firearms. (Amended by Ord. No. 156,363, Eff. 3/29/82.)

(f) “Motor Vehicle” includes, but shall not be limited to, automobiles, trucks, motorcycles, minibikes and go-carts. (Amended by Ord. No. 156,363, Eff. 3/29/82.)

(g) “Noncommercial Purpose” is the use, operation, or maintenance of any sound equipment for other than a “commercial purpose”. “Noncommercial purpose” shall mean and include, but shall not be limited to, philanthropic, political, patriotic, and charitable purposes. (Amended by Ord. No. 156,363, Eff. 3/29/82.)

(h) “Octave Band Noise Analyzer” is an instrument for measurement of sound levels in octave frequency bands which satisfies the pertinent requirements for Class II octave band analyzers of the American National Standard Specifications for Octave, Half-Octave, and Third-Octave Band Filters, S1.11-1966 or the most recent revision thereof. (Amended by Ord. No. 156,363, Eff. 3/29/82.)

(i) “Person” is a person, firm, association, co-partnership, joint venture, corporation, or any entity, private or public in nature. (Amended by Ord. No. 156,363, Eff. 3/29/82.)

(j) “Sound Amplifying Equipment” (Amended by Ord. No. 156,363, Eff. 3/29/82.) is any machine or device for the amplification of the human voice, music or any other sound, but shall not include:

1. Automobile radios, stereo players or television receivers when used and heard only by the occupants of the vehicle in which the same is installed.

2. Radio, stereo players, phonographs or television receivers used in any house or apartment within any residential zone or within 500 feet thereof.

3. Warning devices on emergency vehicles.

4. Horns or other warning devices authorized by law on any vehicle when used for traffic purposes.

(k) “Sound Level” (Noise level) in decibels (dB) is the sound measured with the “A” weighting and slow responses by a sound level meter; except for impulsive or rapidly varying sounds, the fast response shall

be used. (Amended by Ord. No. 156,363, Eff. 3/29/82.)

(l) “Sound Level Meter” is an instrument including a microphone, an amplifier, an output meter, and “A” frequency weighting network for the measurement of sound levels which satisfies the pertinent

requirements for Type S2A meters in American Standard Specifications for sound level meters in S1.4-1971 or the most recent revision thereof. (Amended by Ord. No. 156,363, Eff. 3/29/82.)

(m) “Sound Truck” is any motor vehicle, or any other vehicle regardless of motive power, whether in motion or stationary, which carries, is equipped with, or which has mounted thereon, or attached thereto, any sound amplifying equipment. (Amended by Ord. No. 156,363, Eff. 3/29/82.)

(n) Supplementary Definitions of Technical Terms. Definitions of technical terms not defined herein shall be obtained from American Standard Acoustical Terminology S1-1-1971 or the most recent revision

thereof. (Amended by Ord. No. 156,363, Eff. 3/29/82.)

(Title amended by Ord. No. 156,363, Eff. 3/29/82.)

(a) (Amended by Ord. No. 156,363, Eff. 3/29/82.) Any sound level measurement made pursuant to the provisions of this chapter shall be measured with a sound level meter using the “A” weighting and response as indicated in Section 111.01(k) of this article.

Except when impractical, the microphone shall be located four to five feet above the ground and ten feet or more from the nearest reflective surface. However, in those cases where another elevation is deemed appropriated, the latter shall be utilized.

Interior sound level measurements shall be made at a point at least four feet from the wall, ceiling, or floor nearest the noise source.

Calibration of the sound level meter, utilizing an acoustic calibrator shall be performed immediately prior to recording any sound level data. The ambient noise level and the level of a particular noise being measured shall be the numerical average of noise measurements taken at a given location during a given time period.

(b) (Amended by Ord. No. 156,363, Eff. 3/29/82.) Where the sound alleged to be offending is of a type or character set forth below, the following values shall be added to the sound level measurement of the offending noise:

1. Except for noise emanating from any electrical transformer or gas metering and pressure control equipment existing and installed prior to the effective date of the ordinance enacting this chapter, any steady

tone with audible fundamental frequency or overtones have 200 Hz +5

2. Repeated impulsive noise +5

3. Noise occurring more than 5 but less than 15 minutes in any period of 60 consecutive minutes between the hours of 7:00 a.m. and 10:00 p.m. of any day -5

4. Noise occurring five minutes or less in any period of 60 consecutive minutes, between the hours of 7:00 a.m. and 10:00 p.m. of any day -5

(Amended by Ord. No. 161,574, Eff. 9/8/86.)

(c) For those cases where an objectionable noise is clearly audible, but where the level of ambient noise does not permit direct quantative sound level “A” measurements of the objectionable noise, sound measurements may be performed utilizing an octave band sound analyzer to determine sound level “A” limits as indicated in the Table I below. This table is used to convert the sound pressure level meter readings in dB for each band to SPL in dB(A) for each band.

TABLE I

OCTAVE BAND NOISE VALUES CORRESPONDING TO SOUND LEVEL “A” VALUES

Sound Octave Band Sound Pressure Level, dB re .0002 dyne/cm2 Level Octave Band Center Frequency in Hz “A” 31.5 63 125 250 500 1,000 2,000 4,000 8,000 35 58 50 42 35 32 29 26 23 20 40 61 54 46 40 37 34 31 28 25 45 64 58 51 45 42 39 36 33 30 50 67 61 55 50 47 44 41 38 35 55 70 64 60 55 52 49 46 43 40 60 73 68 64 60 57 54 51 48 45 65 76 72 68 65 62 59 56 53 50 70 79 76 73 70 67 64 61 58 55 75 84 81 78 75 72 69 66 63 60

(d) For those cases where a sound level measurement has been made pursuant to the provisions of this chapter and two or more provisions of this chapter apply, the provision establishing the lower or lowest noise level, respectively, shall be used. (Added by Ord. No. 156,363, Eff. 3/29/82.)

(Amended by Ord. No. 156,363, Eff. 3/29/82.)

Where the ambient noise level is less than the presumed ambient noise level designated in this section, the presumed ambient noise level in this section shall be deemed to be the minimum ambient noise level for purposes of this chapter.

TABLE II

SOUND LEVEL “A” DECIBELS (In this chart, daytime levels are to be used from 7:00 a.m. to 10:00 p.m. and nighttime levels from 10:00 p.m. to 7:00 a.m.)

PRESUMED AMBIENT NOISE LEVEL (dB(A))

ZONE DAY NIGHT A1, A2, RA, RE, RS, RD, RW1, RW2, R1, R2, R3, R4, and R5 50 40

P, PB, CR, C1, C1.5, C2, C4, C5, and CM 60 55 M1, MR1, and MR2 60 55 M2 and M3 65 65

At the boundary line between two zones, the presumed ambient noise level of the quieter zone shall be used.

As an additional remedy, the operation or maintenance of any device, instrument, vehicle, or machinery in violation of any provision of this chapter, which operation or maintenance causes discomfort or annoyance to reasonable persons or which endangers the comfort, repose, health, or peace of residents in the area, shall be deemed and is declared to be a public nuisance and may be subject to abatement summarily by a restraining order or injunction issued by a court order of competent jurisdiction. (Amended by Ord. No. 156,363, Eff. 3/29/82.)

(Added by Ord. No. 156,363, Eff. 3/29/82.)

(a) The Department of Building and Safety shall have the power and duty to enforce the following noise control provisions of this Code: Section 12.14 A.6.(h), Section 12.19 A.4.(b)(1), Section 112.02 and Section 112.04(c). (Amended by Ord. No. 172,086, Eff. 7/30/98.)

(b) The Police Department shall have the power and duty to enforce the following noise control provisions of this Code: Section 41.32, Section 41.40, Section 41.42, Section 41.44, Section 41.57, Section 63.51(m), Section 112.01, Section 112.04, Section 112.05, Section 112.06, Section 113.01, Section 114.01 through Section 114.05, inclusive, Section 115.02 through Section 115.03, inclusive, and Section 116.01. (Amended by Ord. No. 185,601, Eff. 7/18/18.)

(c) Any Building Mechanical Inspector assigned to noise enforcement inspection shall have the power, authority and immunity of a public officer and employee, as set forth in the Penal Code of the State of California, Section 836.5, to make arrests without a warrant whenever such employee has reasonable cause to believe that the person to be arrested has committed a misdemeanor in their presence which is a violation of any provision set forth in Section 111.05(a) of this chapter. The provisions of said Penal Code section regarding issuance of a written promise to appear shall be applicable to arrests authorized herein.