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Home My WebLink About1473 - ORDINANCES - 5/4/1994 ORDINANCE NO. 1473 AN ORDINANCE OF THE CITY OF PALM SPRINGS, CALIFORNIA, AMENDING CHAPTER 11 . 74 (NOISE ORDINANCE) OF THE PALM SPRINGS MUNICIPAL CODE IN REGARD TO WIND ENERGY CONVERSION SYSTEMS . THE CITY COUNCIL OF THE CITY OF PALM SPRINGS, CALIFORNIA, DOES ORDAIN AS FOLLOWS : SECTION 1. Chapter 11. 74 of the Municipal Code is amended with the addition of the following: "11. 74 . 044 WIND ENERGY CONVERSION SYSTEMS (WECS) . 1. PERMIT APPROVAL. A commercial WECS permit shall not be granted unless the applicant demonstrates that the projected WECS noise level will be no greater than that limit specified in subsection 3 below and shall be calculated in accordance with the technical specifications and criteria adopted pursuant to subsections 6-8 below. Noise level limits for WECS shall be considered a property development standard and variances thereunto may be granted pursuant to Section 9406 . 00 of the Zoning Ordinance. 2 . POINT OF MEASUREMENT. The point of measurement for the calculation of the WECS noise level projected pursuant to subsection 3 below shall be determined as follows: (a) All lots in the vicinity of the commercial WECS project property which are actually used for residential, hotel, hospital, school, library or convalescent home purposes shall be identified. For purposes of this subsection, no lot included in the commercial WECS project property shall be deemed actually used for residential, hotel, hospital, school, library or convalescent home purposes . (b) The point of measurement shall be 10 feet from the outside surface of the wall of such structure, identified in (a) above, nearest the WECS being measured. 3 . NOISE LEVEL LIMITS. The noise level or sound level referred to in this section shall mean the higher of the following: (a) 55 dB (A) at the point of measurement. (b) The noise level limit shall be reduced by 5 dB (A) where it is projected that pure tone noise will be generated. A pure tone shall exist if the one-third octave band sound pressure level in the band width of the tone exceeds the arithmetic average of the sound pressure levels on the two contiguous one- third octave bands by 5 dB for center frequencies of 500 Hz and above, and 8 dB for center frequencies between 160 and 400 Hz and by 15 dB for center frequencies less than or equal to 125 Hz. 4 . NOISE ZONES . (a) The development of wind turbines shall be prohibited within 200 feet of any existing land use described in Section 2 (a) above. (b) The development of wind turbines at a distance between 200 feet and 3000 feet from any land use described in Section 2 (a) above shall require the '40-7T , Ord 1473 Page 2 submittal of an acoustical report indicating compliance with the noise level limits and the measurement methodology described in this section. (c) At distances greater than 3000 feet from any land use described in Section 2 (a) above, wind turbine development may be permitted without acoustical study. 5 . COMMERCIAL WECS CHARACTERISTICS . A]_1 noise reports submitted to the City shall include the following information: (a) the dimensions of the commercial WECS :including tower height, total height, hub height and rotor diameter; (b) the name of the manufacturer of the commercial WECS and any applicable model number; (c) a description of the commercial WECS, including axis and wind orientation; and (d) maximum rated power output and the power curve of the WECS with wind speed plotted. relative to power produced. 6 . MEASUREMENT METHODOLOGY" FOR A SINGLE COMMERCIAL 14VECS . All noise measurements shall be made and reported as follows : (a) All noise measurements shall be invade using a sound level meter_ meeting ANSI standard specifications for Type I equipped with Bruel and Kjaer Windscreen (Model No. UA 0237 or 0207) and calibrated to standards of National Bureau of Standards, or other instrumentation as approved by the Director of Planning & Zoning. The specific instrumentation used shall be described in the noise report. (b) Noise measurements shall be made at a height five (5) feet above local terrain. Unusual circumstances may require a different measurement height , but any variance shall be explained in the noise report . (c) Noise measurement data shall be reported as sound pressure levels derived from dB, A weighted . Noise data indexes shall be measured utilizing slow response at a sampling rate of 'A, second or faster. A noise measurement of 10-minute duration should be made with the measurements being recorded on a strip chart recording or similar device. The Le , L501 L801 L90 and L99 should be measured. The measurements should be conducted during a period of relatively constant wind speed. The strip chart recording will show a fairly constant noise level that is intermittently interrupted by higher noise levels due to wind noise and possibly vegetation noise. The lower noise levels recorded on the strip chart are primarily attributable to the WECS . This noise level should correspond roughly to the L90 noise level . The L90 should be considered as the noise level attributable to the WECS . The wind speed during the measurement ,period should not exceed 25 miles per hour as measured at 10 feet above ground. For compliance testing, the 10-minute measurements should be repeated three times . (d) The following parameters during noise measurements shall be noted and included in the noise report : (1) average wind speed; Ord 1473 Page 3 (2) gust wind speed; (3) wind direction; (4) temperature; (5) relative humidity; (6) general weather conditions (e.g. cloudy, clear, inversions) ; (7) terrain (e.g. hills, level, ravines) ; and (S) surrounding vegetation. (e) Three 10-minute noise measurements should be made for compliance testing. (f) The noise level used will be arithmetic average of the L90 levels recorded during the three measurement periods . (g) Noise measurements shall be made in low, medium and high wind speeds and shall be included in the noise report. For low wind speeds, noise measurements shall be made in winds producing an average power output over a minimum thirty-minute sampling period of 20- ± 50 of maximum rated power output. For medium wind speeds, noise measurements shall be made in winds producing an average power output over a minimum thirty-minute sampling period of 500 ± 10°6 of maximum rated power output . For high wind speeds, noise measurements shall be made in winds producing an average power output over a minimum thirty-minute sampling period of 900 ± 10% of maximum rated power output. (h) In order to determine the dB, A weighted, reference level for low wind speeds, noise measurements shall be made 400 feet downwind from the WECS under low speed conditions, i .e. under wind conditions producing an average power output over a minimum fifteen-minute sampling period of 200 ± 5- of maximum rated power output. These measurements shall be included in the noise report . (i) The dB, A weighted, reference level for high wind speeds will be calculated using the L90 levels measured under subsections (g) and (h) above. The high wind speed reference level shall be the sum of low wind speed reference level measured pursuant to subsection (h) above plus the difference between the low wind speed noise level and the high wind speed noise level measured pursuant to subsection (g) above. (j ) If the Director of Planning & Zoning determines that any data provided in the noise report is inconsistent or inadequate, a supplemental noise report prepared by an independent acoustical consultant may be required. 7. MODELING FOR PROJECTED NOISE LEVELS FROM COMMERCIAL WECS ARRAYS . Projected WECS noise level shall be supplied by the permit applicant in accordance with the following procedures : (a) Determine the Noise Level of each WECS (NLW) at the receptor by using the Reference Noise Level (RNL) at 400 feet at high speeds calculated pursuant to subsection 6 (i) above and the following formula: NLW = RNL + 20 log (400/RD) - AAL Where: RD = Receptor Distance to the WECS noise source. WECS noise source shall be assumed to be at the rotor hub for 'oe-11 �z Ord Page�473 4 y horizontal axis WECS and at the midpoint of the rotor axis for vertical axis WECS . AAL = Atmospheric Attenuation Loss determined from Table of Atmospheric Absorption Losses (U.S . Dept . of Transportation, Oct. 1980; Report No. FAA-EE-80-46, Volume I.LI) Method A at 500 humidity and 700F. (b) Determine Projected WECS Noise 'Level (PWNL) using the following formula: PWNL = 10 log [antilog (NLW,/10) + antilog (NLW2/10) + antilog (NLWn/10) I Where: NLW1 = Noise level of first WECS at receptor. NLWZ = Noise level of second WECS at receptor. NLW� = Noise level of nth WECS at receptor. 8 . MEASUREMENT METHODOLOGY FOR A COMMERCIAL WECS ARRAY. All noise measurements shall be made and reported as follows : (a) Required acoustical reports shall be prepared by a Registered Professional Engineer who has an expertise in acoustical engineering or by an Institute of Noise Control Engineer (INCE) . The report will be reviewed and, if appropriate, approved by the City before the issuance of permits . (b) All noise measurements shall be made using a sound level meter meeting ANSI standard specifications for Type I equipped with Bruel and Kjaer Windscreen (Model No. UA 0237 or 0207) and calibrated to standards of National Bureau of Standards . The specific instrumentation used shall be described in the noise report. (c) Noise measurements shall be made at a height five (5) feet above local terrain. Unusual circumstances may require a different measurement height, but any variance shall be explained in the noise report . (d) Noise measurement data shall be reported as sound pressure levels derived from dB, A weighted. Noise data indexes shall be measured utilizing slow response at a sampling rate of iG second or faster. A noise measurement of 10-minute duration should be made with the measurements being recorded on a strip chart recording or similar device. The Leq, L501 L801 L90 and L99 should be measured. The measurements should be conducted during a period of relatively constant wind speed. The strip chart recording will show a fairly constant noise level that is intermittently interrupted by higher noise levels due to wind noise and possibly vegetation. noise. The lower noise levels recorded on the strip chart are primarily attributable to the WECS . This noise level should correspond roughly to the L90 noise level . The L90 should be considered as the noise level attributable to the WECS . The wind speed during the measurement period should not exceed 25 miles per hour as measured at: 10 feet above ground. For compliance testing, the 10-minute measurements should be repeated three times . j - Ord 1473 Page 5 r (e) The following parameters during noise measurements shall be noted and included in the noise report: (1) average wind speed; (2) gust wind speed; (3) wind direction; (4) temperature; (5) relative humidity; (6) general weather conditions (e.g. cloudy, clear, inversions) ; (7) terrain (e.g. hills, level, ravines) ; and (8) surrounding vegetation. (f) Three 10-minute noise measurements should be made for compliance testing. (g) The noise level used will be arithmetic average of the L9 levels recorded during the three measurement periods. " SECTION 2 . EFFECTIVE DATE. This Ordinance shall be in full force and effect thirty (30) days after passage. SECTION 3 . PUBLICATION. The City Clerk is hereby ordered and directed to certify to the passage of this Ordinance, and to cause the same or a summary thereof or a display advertisement, duly prepared according to law, to be published in accordance with law. ADOPTED this 4th day of May 1994. AYES: Members Hodges, Lyons, Reller-Spurgin, Schlendorf and Mayor Maryanov NOES: None ABSENT: None ATTEST: CITY OF PALM SPRINGS, CALIFORNIA ii By City lerk Mayor" REVIEWED & APPROVED: XE- /N/o. I HEREBY CERTIFY that the foregoing Ordinance 1473 was duly adopted by the City Council of the City of Palm Springs, California, in a meeting held on the 4th day of May, 1994, and that same was published in the DESERT SUN, a newspaper of general circulation on April 23 & May 9, 1994. r ( \-�JUDITH SUMICH City Clerk �--��