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SF14980A_Compliance_EME_ Anchor_3.9.2021T-Mobile West LLC • Base Station No. SF14980A 1 Apple Parkway • Cupertino, California R3QB Page 1 of 5 ©2021 Statement of Hammett & Edison, Inc., Consulting Engineers The firm of Hammett & Edison, Inc., Consulting Engineers, has been retained by T-Mobile West LLC, a personal wireless telecommunications carrier, to evaluate proposed modifications to its base station (Site No. SF14980A), sited near similar base stations for use by AT&T Mobility, Sprint, and Verizon Wireless, located on the Apple Park Main Building (AC02) at 1 Apple Parkway in Cupertino, California, for compliance with appropriate guidelines limiting human exposure to radio frequency (“RF”) electromagnetic fields. Executive Summary T-Mobile proposes to replace some of its antennas behind the exterior wall of the penthouse above the roof of the four-story Apple Park Main Building located at 1 Apple Parkway in Cupertino. The proposed operation, together with the existing operations of three other carriers, will comply with the FCC guidelines limiting public exposure to RF energy; certain mitigation measures are recommended to comply with FCC occupational guidelines. Prevailing Exposure Standards The U.S. Congress requires that the Federal Communications Commission (“FCC”) evaluate its actions for possible significant impact on the environment. 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 limit for exposures of unlimited duration at several wireless service bands are as follows: Transmit “Uncontrolled” Occupational Limit Wireless Service Band Frequency Public Limit (5 times Public) Microwave (point-to-point) 1–80 GHz 1.0 mW/cm2 5.0 mW/cm2 Millimeter-wave 24–47 1.0 5.0 Part 15 (WiFi & other unlicensed) 2–6 1.0 5.0 CBRS (Citizens Broadband Radio) 3,550 MHz 1.0 5.0 BRS (Broadband Radio) 2,490 1.0 5.0 WCS (Wireless Communication) 2,305 1.0 5.0 AWS (Advanced Wireless) 2,110 1.0 5.0 PCS (Personal Communication) 1,930 1.0 5.0 Cellular 869 0.58 2.9 SMR (Specialized Mobile Radio) 854 0.57 2.85 700 MHz 716 0.48 2.4 600 MHz 617 0.41 2.05 [most restrictive frequency range] 30–300 0.20 1.0 T-Mobile West LLC • Base Station No. SF14980A 1 Apple Parkway • Cupertino, California R3QB Page 2 of 5 ©2021 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. 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. 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. 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 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”). This methodology is an industry standard for evaluating RF exposure conditions and has been demonstrated through numerous field tests to be a conservative prediction of exposure levels. Site and Facility Description Based upon information provided by T-Mobile and Apple, including drawings by SureSite Consulting Group, LLC, dated January 27, 2021, and Foster + Partners, dated July 10, 2011, respectively, T-Mobile proposes to replace three of its directional panel antennas with three Ericsson Model AIR6449 antennas at the same locations, next to the remaining three CCI Model HPA-65F-BUU-H2 antennas at this site, behind the exterior wall of the equipment penthouse atop the four-story, circular office building located at 1 Apple Parkway in Cupertino. Presently located within other sections of the penthouse are antennas for use by AT&T, Sprint, and Verizon Wireless, mounted in a similar fashion to T-Mobile. The antennas for all four carriers would be mounted at an effective height of about 69 feet above ground, 9 feet above the walkway against that wall. The existing antennas for all four carriers are arranged in groupings around the building, oriented roughly north, east, south, and west. It is noted that the Sprint and T-Mobile antennas are mounted close together in each grouping, except to the south, where T-Mobile does not propose to T-Mobile West LLC • Base Station No. SF14980A 1 Apple Parkway • Cupertino, California R3QB Page 3 of 5 ©2021 install antennas. The following information has been provided by the individual carriers, including the assumed operation for an upgrade to AT&T’s facilities: AT&T (Assumed Operation) • Construction drawings by J5 Infrastructure Partners, dated December 30, 2020 • Ten new Ace Technologies Model APD-2F15D-14P-C antennas next to the remaining eight CCI Model HPA-65F-BUU-H2, employing up to 4° downtilt, oriented in groups of four, two of each, toward 20°T, 110°T, 220°T, and 300°T, and two APD antennas oriented inward in a pair toward 290°T • Maximum effective radiated power in the 20°T, 110°T, 220°T, and 290°T groups 7,940 watts: 1,130 watts at WCS, 1,960 watts at AWS, 1,640 watts at PCS, 950 watts at cellular, 2,260 watts at 700 MHz; Maximum effective radiated power in the 290°T group 6,855 watts: 1,130 watts at WCS, 1,810 watts at AWS, 1,620 watts at PCS, 475 watts at cellular,* and 1,820 watts at 700 MHz Sprint (Existing) • Zoning drawings by Fullerton Engineering Design, dated July 18, 2017 • Four Filtronic Model P6T2BF01 antennas, employing up to 8° downtilt • Oriented toward 80°T, 170°T, 260°T, and 350°T • Maximum effective radiated power 1,970 watts: 1,610 watts at PCS and 360 watts at SMR T-Mobile (Proposed Upgrade) • Construction drawings by SureSite Consulting Group, LLC, dated January 27, 2021 • Three each Ericsson Model AIR6449 and CCI Model HPA-65F-BUU-H2 antennas, employing up to 11° downtilt • Oriented in identical pairs toward 80°T, 260°T, and 350°T (no antennas oriented toward 170°T) • Maximum effective radiated power 47,800 watts: 44,200 watts for BRS,† 1,960 watts at AWS and 1,640 watts at PCS Verizon (Existing) • Zoning drawings by Streamline Engineering and Design, Inc., dated July 27, 2017 • Sixteen JMA Model X7CQAP-FRO-260 antennas, employing up to 6° downtilt * Reduced to comply with FCC occupational exposure limits. † T-Mobile reports 75% downstream duty cycle for operation in the BRS band. T-Mobile West LLC • Base Station No. SF14980A 1 Apple Parkway • Cupertino, California R3QB Page 4 of 5 ©2021 • Oriented in groups of four toward 30°T, 120°T, 210°T, and 300°T • Maximum effective radiated power 10,860 watts: 5,400 watts at AWS, 2,480 watts at PCS, 1,880 watts at cellular, 1,100 watts at 700 MHz Study Results For a person anywhere at ground, the maximum RF exposure level due to the cumulative operation of all four carriers, including RF emissions from similar antennas on Apple Building TA09, about 1,500 feet to the south, is calculated to be 0.20 mW/cm2, which is 22% of the applicable public exposure limit. The maximum calculated level for a person at ground within the center courtyard of Apple Building AC02 is 3.2% of the public exposure limit. The maximum calculated level for a person on the top floor of the building is 11% of the public exposure limit. The maximum calculated level at the underground garage is less than 0.1% of the public exposure limit. The maximum calculated level at the top-floor elevation of any nearby residence is 17% of the public exposure limit; this occurs at the Hamptons Apartment Homes, located about 270 feet to the southwest. It should be noted that these results include several “worst-case” assumptions and therefore are expected to overstate actual power density levels from the proposed operation. Exposure levels on the roof of the building may exceed the applicable public limit in certain areas, as shown in Figures 3 and 4. Recommended Mitigation Measures Due to their mounting locations and height, requiring passage through a locked door to reach the roof, the T-Mobile antennas would not be accessible to unauthorized persons, and so no measures are necessary to comply with the FCC public exposure guidelines. To prevent occupational exposures in excess of the FCC guidelines, it is recommended that appropriate RF safety training, to include review of personal monitor use and lockout/tagout procedures, be provided to all authorized personnel who have access to the roof, including employees and contractors of the several carriers and of Apple. No access directly in front of the antennas themselves, such as might occur during certain maintenance activities on the solar panels and at the view screens in front of the antennas, should be allowed while the pertinent antennas are in operation, unless other measures can be demonstrated to ensure that occupational protection requirements are met. As shown in Figure 4, it is recommended that the top edge outer wall of the roof walkway be marked with a yellow stripe (centered in front of the antennas), and it is recommended that explanatory signs‡ be posted at the roof access ladders, at the solar panel access ladders, at the approximate mid-point of each yellow stripe, near the solar panels above the end ‡ Signs should comply with OET-65 color, symbol, and content recommendations. Contact information for the respective carrier should be provided (e.g., a telephone number) to arrange for access to restricted areas. The selection of language(s) is not an engineering matter, and guidance from the landlord, local zoning or health authority, or appropriate professionals may be required. T-Mobile West LLC • Base Station No. SF14980A 1 Apple Parkway • Cupertino, California R3QB Page 5 of 5 ©2021 parts of each yellow stripe, and on the penthouse wall in front of the antennas, readily visible from any angle of approach to persons who might need to work in those areas. Conclusion Based on the information and analysis above, it is the undersigned’s professional opinion that the proposed operation of the T-Mobile base station at 1 Apple Parkway in Cupertino, California, will comply with the prevailing standards for limiting public exposure to radio frequency energy and, therefore, will 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. Training authorized personnel, marking sections of the outer wall of the roof walkways, and posting explanatory signs are recommended to establish compliance with occupational exposure limits. Authorship The undersigned author of this statement is a qualified Professional Engineer, holding California Registration Nos. E-13026 and M-20676, which expire on June 30, 2021. 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. William F. Hammett, P.E. 707/996-5200 March 8, 2021 FCC Radio Frequency Protection Guide FCC Guidelines Figure 1 1000 100 10 1 0.1 0.1 1 10 100 103 104 105 Occupational Exposure Public Exposure PCS CellFM Po w e r De n s i t y (m W / c m 2) 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 ANSI/IEEE 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 Electromagnetic Fields (f is frequency of emission in MHz) Applicable Range (MHz) Electric Field Strength (V/m) Magnetic Field Strength (A/m) Equivalent Far-Field Power Density (mW/cm2) 0.3 – 1.34 614 614 1.63 1.63 100 100 1.34 – 3.0 614 823.8/ f 1.63 2.19/ f 100 180/ f2 3.0 – 30 1842/ f 823.8/ f 4.89/ f 2.19/ f 900/ f2 180/ f2 30 – 300 61.4 27.5 0.163 0.0729 1.0 0.2 300 – 1,500 3.54 f 1.59 f f /106 f /238 f/300 f/1500 1,500 – 100,000 137 61.4 0.364 0.163 5.0 1.0 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 incorporated those formulas in a computer program capable of calculating, at thousands of locations on an arbitrary grid, the total expected power density from any number of individual radio frequency sources. The program allows for the inclusion of uneven terrain in the vicinity, as well as any number of nearby buildings of varying heights, to obtain more accurate projections. ©2021 RFR.CALC™ Calculation Methodology Assessment by Calculation of Compliance with FCC Exposure Guidelines Methodology Figure 2 ©2021 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  θ BW × 0.1 × Pnet π×D ×h , in mW/cm2, and for an aperture antenna, maximum power density Smax = 0.1 × 16 × η × Pnet π × h 2 , in mW/cm2, where qBW = half-power beamwidth of antenna, in degrees, Pnet = net power input to antenna, in watts, D = distance from antenna, in meters, h = aperture height of antenna, in meters, and h = 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: power density S = 2.56 × 1.64 × 100 × RFF 2 × ERP 4 × π × D2 , in mW/cm2, where ERP = total ERP (all polarizations), in kilowatts, RFF = three-dimensional relative field factor toward point of calculation, and D = distance from antenna effective height to 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 is used in a computer program capable of calculating, at thousands of locations on an arbitrary grid, the total expected power density from any number of individual radio frequency sources. The program also allows for the inclusion of uneven terrain in the vicinity, as well as any number of nearby buildings of varying heights, to obtain more accurate projections. R3QB Figure 3 T-Mobile West LLC • Base Station No. SF14980A 1 Apple Parkway • Cupertino, California Calculated Cumulative RF Exposure Levels on Roof 2021c • Mark yellow caution stripes (see Figure 4) • Post explanatory signs at roof access and at solar panel access ladders • Provide training Recommended Mitigation Measures FE E T 10 0 1 0 2 0 Ca l c u l a t i o n s p e r f o r m e d a c c o r d i n g t o O E T B u l l e t i n N o . 6 5 , A u g u s t 1 9 9 7 . Co l o r s s h o w n r e p r e s e n t p e r c e n t o f a p p l i c a b l e F C C p u b l i c l i m i t . [b l a n k ] < 1 0 0 % >1 0 0 % >5 0 0 % FE E T 10 0 1 0 2 0 Ca l c u l a t i o n s p e r f o r m e d a c c o r d i n g t o O E T B u l l e t i n N o . 6 5 , A u g u s t 1 9 9 7 . Co l o r s s h o w n r e p r e s e n t p e r c e n t o f a p p l i c a b l e F C C p u b l i c l i m i t . [b l a n k ] < 1 0 0 % >1 0 0 % >5 0 0 % Base image from drawing by SureSite Consulting Group, LLC, dated January 27, 2021. Calculations performed according to OET Bulletin 65, August 1997. Notes: See text. Shaded color Sign type Legend:Exceeds Occupational - Yellow CAUTION blank Less Than Public - Green INFORMATION Exceeds 10x Occupational - Orange WARNING Exceeds Public - Blue NOTICE Lighter shaded blue and yellow areas at Verizon from earlier study, dated March 21, 2018. four carrier groupings 50 0 50 100 FEET T-Mobile Sprint Verizon AT&T No r t h R3QB Figure 3 T-Mobile West LLC • Base Station No. SF14980A 1 Apple Parkway • Cupertino, California Calculated Cumulative RF Exposure Levels on Roof 2021c • Mark yellow caution stripes (see Figure 4) • Post explanatory signs at roof access and at solar panel access ladders • Provide training Recommended Mitigation Measures Calculated RF Exposure Levels on Walkways and Solar Panels Typical T-Mobile antennas 8'8' Shaded color Boundary marking Sign type Legend:Exceeds Occupational - Yellow CAUTION N/A blank Less Than Public - Green INFORMATION Exceeds 10x Occupational - Orange WARNING Exceeds Public - Blue NOTICE R3QB Figure 4 Sprint T-Mobile FEET 10 0 1 0 2 0 Calculations performed according to OET Bulletin No. 65, August 1997. Colors shown represent percent of applicable FCC public limit. [blank] <100%>100%>500%Base image from drawing by SureSite Consulting Group, LLC, dated January 27, 2021. Calculations performed according to OET Bulletin 65, August 1997. Notes: See text. 13' 24'