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HomeMy WebLinkAbout3.4r TOWN OF LOS ALTOS HILLS August 6, 2009 Staff Report to the Planning Commission RE: CONDITIONAL USE PERMIT RENEWAL FOR AN EXISTING/ PREVIOUSLY APPROVED WIRELESS COMMUNICATIONS FACILITY. THE FACILITY CONSISTS OF A GROUND EQUIPMENT CABINET AND AN ANTENNA INSIDE OF THE ST. LUKES CHAPEL CHURCH STEEPLE. LANDS OF EPISCOPAL LAYMENS GROUP OF LOS ALTOS (APPLICANT: T -MOBILE); 26410 DUVAL WAY; FILE # 98 -09 -CUP FROM: Nicole Horvitz, Assistant Planner �V APPROVED BY: Debbie Pedro, AICP, Planning Director RECOMMENDATION: That the Planning Commission: Forward a recommendation to the City Council that the Conditional Use Permit be extended for ten (10) years, subject to the amended Conditions of Approval in Attachment 1. BACKGROUND On January 15, 1997 the City Council approved the construction of a PCS (now T -Mobile) wireless communications facility inside the St. Luke's Chapel church steeple and ground equipment cabinet. The use permit was subsequently renewed on July 18, 2002 and December 13, 2005. DISCUSSION The existing wireless facility consists of a single antenna housed within the church steeple. In addition, T -Mobile maintains a 14'6" x 5' wide concrete equipment cabinet pad adjacent to the nursery east of the church. The applicant is not requesting any modification to the site except a new 6' solid fence to enclose the existing ground equipment cabinet to help mitigate the visual impacts from offsite. Pursuant to Government Code Section 65964 (b), the duration of time for any permit renewal for a wireless telecommunications facility should be a minimum of 10 years. Staff has amended condition of approval # 2 in Attachment 1 to comply with State Law. CONCLUSION The facility is operating in compliance with conditions of the approved Conditional Use Permit and the Wireless Communications Facilities Policy. The applicant has submitted a report Item 3.4 Staff Report to the Planning Commission August 6, 2009 Page 2 of 4 demonstrating that the proposed facility will operate within federal RF emissions standards and guidelines. (Attachment 3) Extension of the Use Permit will allow continued operation of the facility for an additional ten (10) years at which time subsequent Planning Commission/City Council review will be required. CEQA STATUS The proposed application is exempt from California Environmental Quality Act (CEQA) pursuant to Section 15301 (a) of the CEQA Guidelines. ATTACHMENTS 1. Original Conditions of Approval (June 13, 2002) with amended condition # 2 2. Applicant's statement requesting permit renewal 3. Radio frequency emissions report by Hammett & Edison, Inc. dated April 27, 2009 4. Photo Simulations 5. Wireless Communications Facilities Policy 6. Site Development Plans Attachment 1 CONDITIONAL USE PERMIT FOR A WIRELESS COMMUNICATIONS FACILITY LANDS OF EPISCOPAL LAYMENS GROUP OF LOS ALTOS (APPLICANT: T -MOBILE); 26410 DUVAL WAY PLANNING DEPARTMENT: 2. Any changes or revisions to the telecommunications facility or its use shall require an amendment to the applicable conditional use pen-nit(s). Additionally, the Planning Director may schedule a review or revocation hearing before the Planning Commission regarding the use permit, if any condition of approval is not being met or the facility is being used inconsistent with the approved use or in violation of Town development codes. 3. The use permit shall expire five (5) ten (10) years from the date of approval. Renewal of the permit must be requested in writing, with appropriate fees, prior to the expiration date. 4. The equipment cabinet shall be painted a color, to be determined by the Planning Department, to blend with the surrounding environment, prior to final inspection of the facility. 5. Landscape screening of the equipment cabinet may be required by the Planning Department upon final inspection if determined to be necessary. 6. The applicant shall submit a signed agreement to the Town, agreeing that, should the use be discontinued by the carrier, all facilities will be removed not later then 90 days after discontinuance of the use or abandonment. The agreement shall be drafted by the City Attorney, and must be signed by the applicant and submitted to the Town prior to acceptance of plans for building plan check. 7. Not later then 30 days after installation and initial operation of the antenna facility, and on or prior to January I" of each year thereafter, testing of radio frequency emissions shall be conduced by qualified professionals and the reports of such testing shall be provided in writing to the Planning Department, with comparison of applicable Federal emissions standards. If at any time the emission levels are shown not to comply with Federal standards, the use permit shall be scheduled for a revocation hearing before the Planning Commission. Staff Report to the Planning Commission October 2, 2008 Page 4 of 4 ENGINEERING DEPARTMENT: 8. Any, and all, changes to the proposed Site Plan shall first be approved by the Town Engineering Department. 9. Any, and all, areas on the project site that have the native material disturbed shall be protected for erosion control during the rainy season and shall be replanted prior to final inspection. CONDITION NUMBER 6 SHALL BE COMPLETED AND SIGNED OFF BY THE PLANNING DEPARTMENT AND THE ENGINEERING DEPARTMENT PRIOR TO ACCEPTANCE OF CONSTRUCTION PLANS FOR PLAN CHECK BY THE BUILDING DEPARTMENT. Attachment 2 May 8, 2009 Ms. Nicole Horvitz Assistant Planner Town of Los Altos Hills 26379 Fremont Road Los Altos Hills, CA 94022 RE: Renewal of existing T -Mobile Conditional Use Permit 467-02 (original CUP 211-05-ZP-SD) 26140 Duval Way Dear Nicole: I am writing to request your review of the enclosed Use Permit Renewal application. These application materials reference a proposal to renew the use permit for an existing unmanned wireless telecommunications facility at 26140 Duval Way. Enclosed please find the following submittal materials: A. Filing Fees. A check for $875.00 is included with this application. B. Completed Application. C. Drawings. Ten sets of 24" x 36" drawings. D. Mailing list and labels. Two sets of mailing labels and list for all property owners within 500 feet of the subject property lines. E. Antenna Master Plan. Please see the enclosed map and list of existing and proposed sites for the next five years included with this application. F. Photosimulations. Please see the enclosed photosimuation showing the proposed new screen fence (the only proposed change). G. EMF Report. Please see enclosed Statement of Consulting Engineers, Hammett & Edison, Inc., dated April 27, 2009. This report states that the facility is operating in compliance with the FCC standards. Thank you for your assistance in reviewing our proposal. Please call me at 415-246-8855 if you have any questions or if you require any additional materials. Sincerely, Tony Kim 100 Clement Street I 3rd Floor I San Francisco, CA 94118 tel 1.415.246.8855 1 fax 1.415.480.1406 Attachment 3 T -Mobile e Rase Station No. SF04627A 26140 Duval Way • Los Altos Hills, California Statement of Hammett & Edison, Inc., Consulting Engineers The firm of Hammett & Edison, Inc., Consulting Engineers, has been retained on behalf of T -Mobile, a personal wireless telecommunications carrier, to evaluate its existing base station (Site No. SF04627A) located at 26140 Duval Way in Los Altos Hills, California, for compliance with appropriate guidelines limiting human exposure to radio frequency ("RF") electromagnetic fields. Prevailing Exposure Standards The U.S. Congress requires that the Federal Communications Commission ("FCC") evaluate its actions for possible significant impact on the environment. In Docket 93-62, effective October 15, 1997, the FCC adopted the human exposure limits for field strength and power density recommended in Report No. 86, "Biological Effects and Exposure Criteria for Radiofrequency Electromagnetic Fields," published in 1986 by the Congressionally chartered National Council on Radiation Protection and Measurements ("NCRP"). Separate limits apply for occupational and public exposure conditions, with the latter limits generally five times more restrictive. The more recent standard, developed by the Institute of Electrical and Electronics Engineers and approved as American National Standard ANSIAEEE C95.1-2006, "Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz," includes similar exposure limits. A summary of the FCC's exposure limits is shown in Figure 1. These limits apply for continuous exposures and are intended to provide a prudent margin of safety for all persons, regardless of age, gender., size, or health. The most restrictive FCC limit for exposures of unlimited duration to radio frequency energy for several personal wireless services are as follows: Personal Wireless Service Approx. Frequency Occupational Limit Public Limit Broadband Radio (`BRS") 2,600 MHz 5.00 mW/cm' 1.00 mW/cm'- Advanced Wireless ("AWS") 2,100 5.00 1.00 Personal Communication ("PCS") 1,950 5.00 1.00 Cellular Telephone 870 2.90 0.58 Specialized Mobile Radio ("SMR") 855 2.85 0.57 Long Term Evolution ("LTE") 700 2.33 0.47 [most restrictive frequency range] 30-300 1.00 0.20 General Facility Requirements Base stations typically consist of two distinct parts: the electronic transceivers (also called "radios' or "channels") that are connected to the traditional wired telephone lines, and the passive antennas that send the wireless signals created by the radios out to be received by individual subscriber units. The transceivers are often located at ground level and are connected to the antennas by coaxial. cables HAMMETT & EDI ON, INC. t CONSULTING ENGINEERS I M046?7A59C ''. '. SAN FRANCISCO Pace 1. of 4 T -Mobile o Base Station No. SF04627A 26140 Duval Way • Los Altos Hills, California about 1 inch thick. Because of the short wavelength of the frequencies assigned by the FCC for. wireless services, the antennas require line -of -sight paths for their signals to propagate well and so are installed at some height above ground. The antennas are designed to concentrate their energy toward the horizon, with very little energy wasted toward the sky or the ground. Along with the low power of such facilities, this means that it is generally not possible for exposure conditions to approach the maximum permissible exposure limits without being physically very near the antennas. tD Computer Modeling Method The FCC provides direction for determining compliance in its Office of Engineering and Technology Bulletin No. 65, "Evaluating Compliance with FCC -Specified Guidelines for Human Exposure to Radio Frequency Radiation," dated August 1997. Figure 2 attached describes the calculation methodologies, reflecting the facts that a directional antenna's radiation pattern is not fully formed at locations very close by (the "near -field" effect) and that at greater distances the power level from. an energy source decreases with the square of the distance from it (the "inverse square law"). The conservative nature of this method for evaluating exposure conditions has been verified by numerous field tests. Site and Facility Description Based upon information provided by T -Mobile, including drawings by Streamline Engineering and Design, Inc., dated April 17, 2009, that carrier has installed three RFS Model APXV 18 -206516 -C -A20 directional panel antennas within the steeple of St. Luke's Chapel in the Hills, located at 26140 Duval Way. The antennas are mounted with 2° downtilt at an effective height of about 34 feet above ground, 22 feet above the main roof, and are oriented toward 1.007, 2207, and 340°T, to provide service in all directions. The maximum effective radiated power in any direction is 3,770 watts, representing simultaneous operation at 2,690 watts for PCS and 1,080 watts for AWS. Located within a flag pole sited about 85 feet away are similar directional panel antennas for use by Sprint Nextel, another wireless telecommunications carrier. For the limited purpose of this study, it is assumed that carrier has installed Andrew Model RR90-17-02 and Model DB844G65 directional panel antennas mounted at an effective height of about 30 feet above ground and operates at a maximum effective radiated power of 3,000 watts, representing simultaneous operation at 1.,500 watts each for PCS and for SMR service. AT&T Mobility had proposed in 2005 to erect a 50 -foot pole at the site, configured to resemble a pine tree, and to mount similar antennas for a third base station at the site. There is no report that the. AT&T facility has been constructed. HAMMETT & EDISON, INC. J ` v CONSULTING ENGINEERS TM04627A596 SAN FRANCISCO Page 2 of 4 T -Mobile - Rase Station No. SF04627A 26140 Duval Way - Los Altos Bills, California Study Results For a person anywhere at ground, the maximum ambient RF exposure level due to the proposed T -Mobile operation by itself is calculated to be 0.0074 mW/cm2, which is 0.74% of the applicable public exposure limit. The maximum calculated cumulative level, at ground for the simultaneous operation of T -Mobile and Sprint Nextel, is 12% of the public exposure limit. The maximum calculated cumulative level at the second -floor elevation of any nearby building* is 36% of the public exposure limit. It should be noted that these results include several "worst-case" assumptions and therefore are expected to overstate actual power density levels. Recommended Mitigation Measures Due to their mounting locations, the T -Mobile antennas are not accessible to the general public, and so no mitigation measures are necessary to comply with the FCC public exposure guidelines. To prevent occupational exposures in excess of the FCC guidelines, no access within 4 feet directly in front of the T -Mobile antennas themselves, such as might occur during maintenance work on the roof, should be allowed while the base station is in operation, unless other measures can be demonstrated to ensure that occupational protection requirements are met. Posting explanatory warning signs t at the antennas and/or on the steeple below the antennas, such that the signs would be readily visible from. any angle of approach to persons who might need to work within that distance, would be sufficient to meet FCC - adopted guidelines. Similar measures should already be in place for the other carrier at the site; applicable keep -back distances have not been determined as part of this study. Conclusion Based on the information and analysis above, it is the undersigned's professional opinion that the T -Mobile base station located at 26140 Duval Way in Los Altos Hills, California, complies with the prevailing standards for limiting public exposure to radio frequency energy and, therefore, does not for this reason cause a significant impact on the environment. The highest calculated level in publicly accessible areas is much less than the prevailing standards allow for exposures of unlimited duration. This finding is consistent with measurements of actual exposure conditions taken. at other operating base stations. Posting of explanatory signs is recommended to establish compliance with occupational exposure limitations. Located about 50 feet away, based on aerial photographs from Google Maps. Warning signs should comply with OET-65 color, symbol, and content recommendations. Contact information should be provided (e.g., a telephone number) to arrange for access to restricted areas. The selection of lantivaje(s) is not an engineering matter, and guidance from the landlord, local zoning, or health authority, or appropriate professionals may be required. HAMMETT & EDISON INC. C:ONSUGTWGENG INEERS TM04627A596 .. .. ..r...c i SAN FRANCISCO Page 3 of 4 T -Mobile • Base Station No. SF04627A 26140 Duval Way • Los Altos Hills, California Authorship The undersigned author of this statement is a qualified Professional Engineer, holding California Registration Nos. E-13026 and N1-20676, which expire on June 30, 2009. This work. has been carried out under his direction, and all statements are true and correct of his own knowledge except, where noted, when data has been supplied by others, which data he believes to be correct. April 27, 2009 HAMMETT & EDISON, INC. fMU46�7A59C CONSULTII 1G ENGI,tiEERS SAN FRANCISCO Pale 4 u1' 4 FCC Radio Frequency Protection Guide The U.S. Congress required (1996 Telecom Act) the Federal Communications Commission ("FCC") to adopt a nationwide human exposure standard to ensure that its licensees do not, cumulatively, have a significant impact on the environment. The FCC adopted the limits from Report No. 86, `Biological Effects and Exposure Criteria for Radiofrequency Electromagnetic Fields," published in 1986 by the Congressionally chartered National Council on Radiation Protection and Measurements ("NCRP"). Separate limits apply for occupational and public exposure conditions, with the latter limits generally five times more restrictive. The more recent standard, developed by the Institute of Electrical and Electronics Engineers and approved as American National Standard ANSIJEEE C95.1-2006, "Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz," includes similar limits. These limits apply for continuous exposures from all sources and are intended to provide a prudent margin of safety for all persons, regardless of age, gender, size, or health. As shown in the table and chart below, separate limits apply for occupational and public exposure conditions, with the latter limits (in italics and/or dashed) up to five times more restrictive: Frequency Applicable Range (MHz) 0.3— 1.34 1.34— 3.0 3.0— 30 30— 300 300— 1,500 1,500— 100,000 1000 100 3 1.0 0 v 0.1 Electromagnetic Fields (f is frequency of emission in MHz Electric Magnetic Equivalent Far -Field Field Strength Field Strength Power Density (V/m) (A/m) (mW/cm`) 614 614 1.63 1.63 100 100 614 823.8/f 1.63 2.19/f 100 1,30/.f 1842/ f 823.8/f' 4.89/ f 2.19/f' 900/ f` /8% 61.4 27.5 0.163 0.0729 1.0 0.2 3.54•4 1.59f -f/106 •ff/238 f/300 f/1500 137 61.4 0.364 0.163 5.0 1.0 Occupational Exposure ` PCS Cell � FM Public ExxDosure 0.1 1 10 100 103 1.04 105 Frequency (MHz) Higher levels are allowed for short periods of time, such that total exposure levels averaged. over six or thirty minutes, for occupational or public settings, respectively, do not exceed the limits, and higher levels also are allowed for exposures to small areas, such that the spatially averaged levels do not exceed the limits. However, neither of these allowances is incorporated in the conservative calculation formulas in the FCC Office of Engineering and Technology Bulletin No. 65 (August 1997) for projecting field levels. Hammett & Edison has built those formulas into a proprietary program that calculates, at each location on an arbitrary rectangular grid, the total expected power density from any number of individual radio sources. The program allows for the description of buildings and uneven. terrain, if required to obtain more accurate projections. `FI HAMMETT & EDISON, INC. CONSULTING ENGINEERS FCC Guidelines SAN FRANCISCO FigUrre I RFR.CALCTM Calculation Methodology Assessment by Calculation of Compliance with FCC Exposure Guidelines The U.S. Congress required (1996 Telecom Act) the Federal Communications Commission ("FCC") to adopt a nationwide human exposure standard to ensure that its licensees do not, cumulatively, have a significant impact on the environment. The maximum permissible exposure limits adopted by the FCC (see Figure 1) apply for continuous exposures from all sources and are intended to provide a prudent margin of safety for all persons, regardless of age, gender, size, or health. Higher levels are allowed for short periods of time, such that total exposure levels averaged over six or thirty minutes, for occupational or public settings, respectively, do not exceed the limits. Near Field. Prediction methods have been developed for the near field zone of panel (directional) and whip (omnidirectional) antennas, typical at wireless telecommunications base stations, as well as dish (aperture) antennas, typically used for microwave links. The antenna patterns are not fully formed in the near field at these antennas, and the FCC Office of Engineering and Technology Bulletin No. 65 (August 1997) gives suitable formulas for calculating power density within such zones. For a panel or whip antenna, power density S = 180 x 0.1 x P"t rmW B JTxD xh' in /cm sw 0.1x16x77xPi1E, mW and for an aperture antenna, maximh` um power density Smax = , in /cm atx where 6gW = half -power beamwidth of the antenna, in degrees, and Pnet = net power input to the antenna, in watts, D = distance from antenna, in meters, h = aperture height of the antenna, in meters, and 77 = aperture efficiency (unitless, typically 0.5-0.8). The factor of 0.1 in the numerators converts to the desired units of power density. Far Field. OET-65 gives this formula for calculating power density in the far field of an individual RF source: 2.56x1.64x100xRFF' xERP power density S = in mw/cm', 4xatxD` where ERP = total ERP (all polarizations), in kilowatts, RFF = relative field factor at the direction to the actual point of calculation, and D = distance from the center of radiation to the point of calculation, in meters. The factor of 2.56 accounts for the increase in power density due to ground reflection, assuming a reflection coefficient of 1..6 (1.6 x 1.6 = 2.56). The factor of 1.64 is the gain of a half -wave dipole relative to an isotropic radiator. The factor of 100 in the numerator converts to the desired units of power density. This formula has been built into a proprietary program that calculates, at each location on an arbitrary rectangular grid, the total expected power- density from any number of individual radiation sources. The program also allows for the description of uneven terrain in the vicinity, to obtain more accurate projections. HAMMETT & EDISON, INC. p CONSULTING EI\TGINEEPS Methodology _,..:::,::r;•r; SAN FRANCISCO - Figure. 2 i L t IC ;M, ,�y =�•� l'Sr�.br r Ey�� 4 �,;9 r p�� yi '. �y�•'�.,!•s 2 :. 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