(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.
OCTAVE BAND NOISE VALUES CORRESPONDING TO SOUND LEVEL “A” VALUES
Sound Level | Octave Band Sound Pressure Level, dB re .0002 dyne/cm2 Octave Band Center Frequency in Hz | ||||||||
“A” | 31.5 | 63 | 125 | 250 | 500 | 1000 | 2000 | 4000 | 8000 |
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.)