C Squared Systems, LLC 65 Dartmouth Drive Auburn, NH 03032 (603) 644-2800 support@csquaredsystems.com RADIO FREQUENCY EXPOSURE REPORT D E E RI NG H I G H S CH O O L 3 7 0 S T E VE NS AV E N UE P O RT L A N D, ME 0 4 1 0 3 June 12, 2015 Table of Contents 1. Introduction ..............................................................................................................................................1 2. FCC Guidelines for Evaluating RF Exposure Limits .................................................................................1 3. RF Sources ................................................................................................................................................2 4. Survey Equipment and Procedures ............................................................................................................3 5. Survey Locations & Results .......................................................................................................................4 6. Summary of Findings ................................................................................................................................5 7. Statement of Certification..........................................................................................................................6 Attachment A: References ...............................................................................................................................7 Attachment B: FCC Limits for Maximum Permissible Exposure (MPE) .........................................................8 Attachment C: Probe Calibration Certification ..............................................................................................10 Attachment D: Meter Calibration Certification ..............................................................................................11 Attachment E: Survey Locations ...................................................................................................................12 List of Tables Table 1: Instrumentation Information ........................................................................................................................... 3 Table 2: Measured %MPE Values for the General Population .................................................................................... 4 Table 3: FCC Limits for Maximum Permissible Exposure .......................................................................................... 8 List of Figures Figure 1: City of Portland / U.S. Cellular Guyed Tower .............................................................................................. 2 Figure 2: Example WIFI Access Point ......................................................................................................................... 2 Figure 3: Graph of FCC Limits for Maximum Permissible Exposure (MPE) .............................................................. 9 i 1. Introduction At the request of Portland Public Schools, radiofrequency emissions measurements were performed by C Squared Systems, LLC on June 9, 2015 at the Deering High School, located at 370 Stevens Avenue in Portland, ME. The focus of the assessment was to measure and record radio frequency exposure limits within the school. 2. FCC Guidelines for Evaluating RF Exposure Limits In 1985, the FCC established rules to regulate radio frequency (RF) exposure from FCC licensed antenna facilities. In 1996, the FCC updated these rules, which were further amended in August 1997 by OET Bulletin 65 Edition 97-01. These new rules include Maximum Permissible Exposure (MPE) limits for transmitters operating between 300 kHz and 100 GHz. The FCC MPE limits are based upon those recommended by the National Council on Radiation Protection and Measurements (NCRP), developed by the Institute of Electrical and Electronics Engineers, Inc., (IEEE) and adopted by the American National Standards Institute (ANSI). The FCC general population/uncontrolled limits set the maximum exposure to which most people may be subjected. General population/uncontrolled exposures apply in situations in which the general public may be exposed, or in which persons that are exposed as a consequence of their employment may not be fully aware of the potential for exposure or cannot exercise control over their exposure. Public exposure to radio frequencies is regulated and enforced in units of milliwatts per square centimeter (mW/cm2). The general population exposure limits for the various frequency ranges are defined in the attached “FCC Limits for Maximum Permissible Exposure (MPE)” in Attachment B of this report. Higher exposure limits are permitted under the occupational/controlled exposure category, but only for persons who are exposed as a consequence of their employment provided they are fully aware of the potential for exposure, and are able to exercise control over their exposure. General population/uncontrolled limits are five times more stringent than the levels considered acceptable for occupational, or radio frequency trained individuals. Attachment B contains excerpts from OET Bulletin 65 and defines the Maximum Exposure Limit. Finally, it should be noted that the MPE limits adopted by the FCC for both general population / uncontrolled exposure and for occupational / controlled exposure incorporate a substantial margin of safety and have been established to be well below levels generally accepted as having the potential to cause adverse health effects. C Squared Systems, LLC 1 June 12, 2015 3. RF Sources There are multiple RF sources inside and on the roof of the school, including a guyed tower which supports antennas for the City of Portland and U.S. Cellular, a 4x4 MIMO 2.4/5GHz WIFI system with access points throughout the school, walkietalkies used by PPS maintenance personnel, and various electronics, including computer monitors, iPad tablets, personal cell phones, and televisions. Figure 1: City of Portland / U.S. Cellular Guyed Tower Figure 2: Example WIFI Access Point C Squared Systems, LLC 2 June 12, 2015 4. Survey Equipment and Procedures Frequencies from 300 kHz to 50 GHz were measured using the Narda Probe EA 5091, E-Field, shaped, FCC probe in conjunction with the NBM550 survey meter. The EA 5091 probe is “shaped” such that in a mixed signal environment (i.e.: more than one frequency band is used in a particular location), it accurately measures the percent of MPE. From FCC OET Bulletin No. 65 - Edition 97-01 – “A useful characteristic of broadband probes used in multiple-frequency RF environments is a frequency-dependent response that corresponds to the variation in MPE limits with frequency. Broadband probes having such a "shaped" response permit direct assessment of compliance at sites where RF fields result from antennas transmitting over a wide range of frequencies. Such probes can express the composite RF field as a percentage of the applicable MPEs”. Probe Description - As suggested in FCC OET Bulletin No. 65 - Edition 97-01, the response of the measurement instrument should be essentially isotropic, (i.e., independent of orientation or rotation angle of the probe). For this reason, the Narda EA 5091 probe was used for these measurements. Sampling Description - At each measurement location, a spatially averaged measurement is collected over the height of an average human body. The NBM550 survey meter performs a time average measurement while the user slowly moves the probe over a distance range of 20 cm to 200 cm (about 6 feet) above ground level. The results recorded at each measurement location include average values over the spatial distance. Instrumentation Information - A summary of specifications for the equipment used is provided in the table below. Manufacturer Probe Calibration Date Calibration Interval Meter Calibration Date Calibration Interval Probe Specifications Narda Microwave EA 5091, Serial# 01135 June 2014 24 Months NBM550, Serial# B-1149 June 2014 24 Months Frequency Range Field Measured 300 KHz-50 GHz Electric Field Standard U.S. FCC 1997 Occupational/Controlled Measurement Range 0.2 – 600 % of Standard Table 1: Instrumentation Information 1 Instrument Measurement Uncertainty - The total measurement uncertainty of the NARDA measurement probe and meter is no greater than ±3 dB (0.5% to 6%), ±1 dB (6% to 100%), ±2 dB (100% to 600%). The factors which contribute to this include the probe’s frequency response deviation, calibration uncertainty, ellipse ratio, and isotropic response 2. Every effort is taken to reduce the overall uncertainty during measurement collection including pointing the probe directly at the likely highest source of emissions. 1 2 Copies of Certificates of Calibration are provided as Attachments C and D to this report. For further details, please refer to Narda Safety Test Solutions NBM550 Probe Specifications, pg. 64 http://www.narda-sts.us/pdf_files/DataSheets/NBM-Probes_DataSheet.pdf C Squared Systems, LLC 3 June 12, 2015 5. Survey Locations & Results Table 2 below lists the measurements recorded on the Deering High School property at 39 different locations identified by the school prior to the survey (Reference Attachment E). Measurements were recorded at each location twice; once with the school’s WIFI network active and again with the WIFI network inactive. The table also lists the presence of a WIFI access point for each measurement location. Pictures of each measurement location are not included, but can be furnished upon request. All values shown in Table 2 are in reference to the FCC General Population MPE limit. For any rooms where WIFI access points were present, the measurement was recorded within four feet of the access point. Meas. Number Measurement Location WIFI Access Point Present? Measured %MPE Value (WIFI ON) Measured %MPE Value (WIFI OFF) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 Room 212 2nd Floor Walkway to Cafeteria Nurse's Office 2nd Floor Conference Room Ludlow Street Side of Cafeteria Guidance Office Room 301 Room 302 Room 303 Room 304 Room 305 Room 306 Room 307 Room 308 3rd Floor Walkway to Library Room 309 Room 310 Room 311 Room 312 (SW Windows) Room 312 (SE Windows) Room 313 Room 314 Room 315 Room 316 Rear of Library (Under WIFI AP) Front of Library Room 317 Room 318 Room 319 Room 320 Room 321 Room 322 Room 323 Room 401 (Egress Door Open) Room 401 (Egress Door Closed) Room 402 (Egress Door Open) Room 402 ( Egress Door Closed) Room 403 Bus Stop on Ludlow Street Yes No No Yes No Yes No Yes Yes Yes Yes No No Yes No Yes No Yes No No Yes No Yes No Yes Yes Yes Yes No Yes Yes Yes No No No No No No No < 1.00 < 1.00 < 1.00 < 1.00 < 1.00 < 1.00 1.04 1.35 < 1.00 < 1.00 < 1.00 < 1.00 < 1.00 < 1.00 < 1.00 < 1.00 < 1.00 1.09 1.02 1.07 1.31 1.47 1.54 1.02 1.32 1.47 1.01 1.08 < 1.00 < 1.00 < 1.00 1.06 1.22 < 1.00 < 1.00 < 1.00 < 1.00 1.66 1.79 1.30 1.15 1.02 < 1.00 < 1.00 1.22 1.25 1.27 1.13 1.18 < 1.00 < 1.00 < 1.00 1.18 1.63 1.02 < 1.00 < 1.00 < 1.00 < 1.00 < 1.00 < 1.00 < 1.00 1.06 1.14 1.39 1.46 1.07 1.27 1.26 1.09 < 1.00 < 1.00 < 1.00 < 1.00 < 1.00 < 1.00 < 1.00 < 1.00 Table 2: Measured %MPE Values for the General Population 3 3 Due to measurement uncertainty at low levels, any readings < 1.00% FCC Uncontrolled/General Population MPE are listed as such. See Section 4 for the measurement range of the probe. C Squared Systems, LLC 4 June 12, 2015 It is important to note that it should not be assumed that measurements recorded while the WIFI network was turned off will necessarily be lower than measurements recorded while the WIFI network was active. Any and all other radiofrequency (RF) sources in the vicinity (two-way radio communications, police, fire, public safety transmissions, and cellular traffic are all uncontrolled, that is, they will have variations in transmitting power levels depending upon the activity level and traffic load on the networks. All of these RF sources may contribute to the emissions levels measured. For example, during the noon recess, the access points within the classrooms will likely have lower activity on them yet the number of students simultaneously using cell phones and wireless devices may increase, which in turn could increase the overall power density of the RF environment in the immediate vicinity of a deactivated access point. 6. Summary of Findings The measurement results for this site find that there are currently no areas within the building, or at ground level around the building, where percent of MPE values will exceed the General Population limit, as defined by the FCC. • • • The highest measurement recorded within the school while the WIFI network was active was at Location 38 (Room 403) and was recorded at 1.66% (Average Uncontrolled/General Population). The highest measurement recorded within the school while the WIFI network was inactive was at Location 15 (3rd Floor Walkway to Library) and was recorded at 1.63% (Average Uncontrolled/General Population). The measurement recorded outside the school at Location 39 (Bus Stop on Ludlow Street) was recorded at 1.79% (Average Uncontrolled/General Population). Our findings show that radio frequency emissions at the Deering High School are well below the exposure limits established by the FCC. The highest %MPE measured within or outside of the premises was recorded to be less than 2% of the limits established by the FCC for the Average Uncontrolled/General Population. It should also be noted that the new limits established by the FCC in 1997 are more conservative than the limits originally adopted by the FCC in 1985. C Squared Systems, LLC 5 June 12, 2015 7. Statement of Certification I certify to the best of my knowledge that the statements in this report are true and accurate. The measurements follow guidelines set forth in ANSI/IEEE Std. C95.3, ANSI/IEEE Std. C95.1, ANSI/IEEE Std C95.7 and FCC OET Bulletin 65 Edition 97-01. ____________________________ June 12, 2015 Daniel L. Goulet C Squared Systems, LLC C Squared Systems, LLC Date 6 June 12, 2015 Attachment A: References OET Bulletin 65 - Edition 97-01 - August 1997 Federal Communications Commission Office of Engineering & Technology ANSI C95.1-1982, American National Standard Safety Levels With Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 300 kHz to 100 GHz. IEEE-SA Standards Board IEEE Std C95.3-1991 (Reaff 1997), IEEE Recommended Practice for the Measurement of Potentially Hazardous Electromagnetic Fields - RF and Microwave. IEEE-SA Standards Board IEEE Std C95.7-2005, IEEE Recommended Practice for Radio Frequency Safety Programs, 3 kHz to 300 GHz. IEEE-SA Standards Board C Squared Systems, LLC 7 June 12, 2015 Attachment B: FCC Limits for Maximum Permissible Exposure (MPE) (A) Limits for Occupational/Controlled Exposure 4 Frequency Range (MHz) 0.3-3.0 3.0-30 30-300 300-1500 1500-100,000 Electric Field Strength (E) (V/m) 614 1842/f 61.4 - Magnetic Field Strength (E) (A/m) 1.63 4.89/f 0.163 - Power Density (S) (mW/cm2) (100)* (900/f2)* 1.0 f/300 5 Averaging Time E 2, H 2 or S (minutes) 6 6 6 6 6 (B) Limits for General Population/Uncontrolled Exposure 5 Frequency Range (MHz) 0.3-1.34 1.34-30 30-300 300-1500 1500-100,000 f = frequency in MHz Electric Field Strength (E) (V/m) 614 824/f 27.5 - Magnetic Field Strength (E) (A/m) 1.63 2.19/f 0.073 - Power Density (S) (mW/cm2) (100)* (180/f2)* 0.2 f/1500 1.0 Averaging Time E 2, H 2 or S (minutes) 30 30 30 30 30 * Plane-wave equivalent power density Table 3: FCC Limits for Maximum Permissible Exposure 4 Occupational/controlled limits apply in situations in which persons are exposed as a consequence of their employment provided those persons are fully aware of the potential for exposure and can exercise control over their exposure. Limits for occupational/controlled exposure also apply in situations when an individual is transient through a location where occupational/controlled limits apply provided he or she is made aware of the potential for exposure. 5 General population/uncontrolled exposures apply in situations in which the general public may be exposed, or in which persons that are exposed as a consequence of their employment may not be fully aware of the potential for exposure or cannot exercise control over their exposure. C Squared Systems, LLC 8 June 12, 2015 Plane-wave Equivalent Power Density 1.34 Frequency (MHz) 1,500 100,000 Figure 3: Graph of FCC Limits for Maximum Permissible Exposure (MPE) C Squared Systems, LLC 9 June 12, 2015 Squared Systems, LLC 10 June 12, 2015 Hard: Hi1:va Ell'l Certi?cate of Calibration L-J Cmunicllinm. Hunk Him-Imume hereby milk; than n-fnmard I'll: ham ?lih'llud by personnel In Hurda': approved In! the imm mum. at MS. all publiad'hud Speci?catimu. and she ?librarian Im hen [inform wuh tun thu. Smut applicahI-c. iS lit-cabin to Ruin-u] Institute nmendI-dsand Hnda's calibration mm m: 1h: Huimul lnniu: mfsundads md lnal :1th lam-curl ?libntim facililin. it an In mam lem.? SYSTEMS AUBURN. NH 03032 Made! 2402mm Sc?al a: 135 FCC SHAPED PRUBE 3m PD {100366 11.0.13: @c?m I?ll [II-ti wit-.1! ftrli?calc II: IJESIE I I?ll-Fulani?le ?Ln?h ?Him-t.- N5. mm m: 1.313% Attachment C: Probe Calibration Certi?cation Squared Systems, LLC 11 June 12, 2015 If If"; 1. Certi?cate of Calibration L-il Cumnimimn, Hard: ?Wm-Fm Inn-h}- cmi?u. [hm 1h: min-um hula-m1!? bun alibi-lied by quali?ed ml In Hrd? mind In! Pl'??lm lemmum im mum-I1. til-rim}. publide wirumm nib-jinn has been mint-mud Hitlcu'uuhunu?imlh?. Huda': nth-lion mums uncut-l: 1min: ?lial-? Iranian: aim-Ind TM- lull-g- ?lm Ilth by lh: hut-uh calth hililin. Emmi SQUARE-ID SYSTEMS LLC AUBURN. NH 0303:! WI II: 24mm] Scrial 3-1149 Dmripli??i METER. BASIC UNIT FUJI: 000366 Du: Calibrated: ILD. 133525- Mai-u wim- Emilia-m: ll': IJESIS mm?-h?un?u-mu?mu. ?mum-Im?l Tl; ?'l-Il'lvfl'l'l Attachment D: Meter Calibration Certi?cation Attachment E: Survey Locations Portland Public Schools Requested Locations for RF Exposure Assessment by C2 June 9, 2015 beginning at 9:30 AM Room Number/Location Notes Second Floor Walkway to cafeteria Nurse's. station Conference Room Cafeteria windowwall closest to Ludlow Street Third Floor Guidance 301 302 303 304 305 306 30? 303 to library 309 310 311 312 313 314 315 316 Library 31? 318 319I 320 321 322 323 Fourth Floor 401 egress door open 401 egress door closed 402 egress door open 402 egress door closed 403 Grounds Bus drop offand pick up Ludlow Street Squared Systems, LLC 12 June 12, 2015