electromagnetic field measurements 1

Electromagnetic Field Field

measurements i h d in home and office space

1

IEEE Switchgear meeting, San Diego, September 2015

Nenad Uzelac

Agenda

1. Introduction1. Introduction2. EM spectrum3 Measurements & Equipment3. Measurements & Equipment4. EMF survey5. EMF exposure limits6. Is it safe? 6 s sa e7. Conclusions

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EM spectrum

Focus on Non-Ionizing Spectrum

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Focus on Non-Ionizing Spectrum

EM Spectrum (cont)

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EM spectrum

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Non-ionizing radiation

• Non-ionizing radiationNon ionizing radiationrefers to any type of EM radiation that does not carryradiation that does not carry enough energy per quantum (photon energy) to ionize(photon energy) to ionize atoms or molecules

• Can’t completely remove an• Can t completely remove an electron from an atom or moleculemolecule

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Source of EM radiation

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EMF measurements

a) Low frequency AC Electric ) q yfields

b) L f AC tib) Low frequency AC magnetic fields

c) Radio/microwave frequency

d) LV Conductive transients and harmonics (dirty ( yelectricity)

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EMF Measuring equipment • Basic, multi

purpose.purpose.• Combination EMF

metersmeters • Measure Electric,

M ti dMagnetic, and EMF field with one i t tinstrument

• Inexpensive • Good for EMF walk

around 9

EMF measuring equipment (cont)

• Digital dedicatedDigital, dedicated meters

• min/max/average• min/max/average functionsC l d t• Can log data

• 3-axis• Good for conducting

EMF surveyy

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EMF measuring equipment (cont)

• Spectrum analyzers‘Spectrum analyzers• Measure and record

EMF spectrum (fromEMF spectrum (from Hz to GHz)C• Can measure occasional EMF

di ti lik fradiation, like from smart meters.

• Pricey11

a) Low frequency AC electric fi ldfields

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Measure E field strength• E field arise from Voltage.

Higher the voltage, higherHigher the voltage, higher the field

• Measuring Low frequency• Measuring Low frequency E fieldU t 400kH• Up to 400kHz

• Measurement in V/m• If it is single axis device,

need to repeat pmeasurements in all 3 axis

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Gauss law

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E field around cable

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E field around the house

• Measure outside the househouse

• 0.2 V/m - 2 V/m

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Sources of the E field

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Walk around – finding hot spots

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E field inside the house

• Measure at different distances from thedistances from the source(s)M t 3 diff t• Measure at 3 different axis, if using a 1-axis

tmeter • Measure both with sources

turned on and turned off• Measure at different time

of the day. Keep log19

b) Low frequency AC magnetic fi ld fields

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Measure M field strength

• Magnetic field arise fromMagnetic field arise from current. Higher the current higher the fieldcurrent, higher the field.

• Use Gaussmeters to measure ULF (ultra lowmeasure ULF (ultra low frequency) from 20Hz to 2kHz2kHz

• Measuring magnetic flux d itdensity

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Gauss meter

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Ampere's law

The line integral of theThe line integral of the magnetic B-field (in tesla, T) around closedtesla, T) around closed curve C is proportional to the total current Iencto t e tota cu e t encpassing through a surface Ssu ace S

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Magnetic field drop with distance

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Magnetic field Units

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M field around house

• Measure outside theMeasure outside the house

• 0 3mG 0 7mG• 0.3mG – 0.7mG

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Sources of M field

27Source: Lipa. www.lipower.org

Magnetic field sources

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Walk around – finding hot spots

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Hot spots (continious)

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0.3mG 6ft from the alarm clock

15.5 mG 6” from the alarm clock

Hot spots (when used)

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Magnetic field

Source: World Health Organization (WHO), Extremely Low Frequency Fields, Environmental Health Criteria Monograph No 238 Geneva World Health Organization 2007 modified from Table 6 p 33

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Criteria Monograph No. 238, Geneva, World Health Organization, 2007, modified from Table 6, p. 33.

33

Medical College of Wisconsin website by John Moulder, Power Lines and Cancer FAQs,<http://www.mcw.edu/radiationoncology/ourdepartment/radiationbiology/Power-Lines-and-Cancer-FAQs.htm>,accessed on April 10, 2013.

c) Radio frequency

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Measure RF/MW power density• Measuring EM power

density in HF, VHFdensity in HF, VHF and UHF range.

• Defined as the amount• Defined as the amount of power per unit area in a radiatedin a radiated microwave field or other type of EMFother type of EMF field. A 10Mh• Approx: 10Mhz –10Ghz range 35

Measure far field

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Unit conversion

For Far Field

Pd – power density (W/m2)E – RMS value of El field (V/m)Z impendence of free spaceZ0 – impendence of free space

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Walk through – hot spots

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Spot check in different locations

39Near router Near computer Living room Bedroom

Microwave

This explains why my Wi-Fi breaksmy Wi Fi breaks down when I turn on the microwave

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on the microwave.

Microwave (cont)

• They bothThey both run on the samesame frequency rangerange

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2.46 GHz

Data logging / recording

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Spectrum Analyzer software

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d) LV conductive transients

“Di t El t i it ”44

“Dirty Electricity”

Transients and harmonics traveling on 120V/220V AC li

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lines

Source of transients

• Dimmer Switches.Dimmer Switches.• Fluorescent Lighting.

Computers and Laptops• Computers and Laptops.• Printers and Scanners.• Solar Panels.• Stereo Equipment.S e eo qu p e• Video Game Systems.• TV• TV

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Microsurge meter

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GS unit

48www.magdahavas.com

GS unit (cont)

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Filters

Installing capacitive filters remove the transient voltages from

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the 120/220V power lines

Installing filters

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Installing filters

52No filter With 1 filter With 2 filters

Installing filters

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EMF surveyEMF survey

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Electromagnetic field survey

1 Measure outside house/condo1. Measure outside house/condo 2. Measure inside the house with turned off

powerpower3. Walk through – determining hot spots

ith t dwith turned on power4. Detailed spot measurements in area

where we spend most of the time 5. Data logging, if possiblegg g, p6. Document results

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Create Report

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EMF Exposure limitsp

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ICNIRP & IEEE

• International Commission on Non-Ionizing R di ti P t tiRadiation Protection

• Established exposure guidance in 1993, d t d i 2010updated in 2010

• The assumption for establishing safe limits is that levels of non ionizing EMF radiation thatthat levels of non-ionizing EMF radiation that do not cause heating in human tissue are safesafe

• They are also based on short term exposure• Majority countries in the world use those limitsMajority countries in the world use those limits

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ICNIRP & IEEE limits

59Martin Blank, Phd, “Overpowered”, 2014, page 164

“A Global Survey and Comparison of Different Regulatory Approaches to Non-Ionizing RADHAZ and Spurious Emissions”

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Ionizing RADHAZ and Spurious Emissions

http://www.who.int/docstore/peh-emf/EMFStandards/who-0102/Worldmap5.htm

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In the US

http://www.emfs.info/limits/limits-usa/

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Is it Safe?

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So, is EMF exposure safe?

Conflicting information in media

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Is it safe?

“No definitive conclusions from experts

“

“& C C O OG C C O

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EMF & CANCER: EPIDEMIOLOGIC EVIDENCE TO DATEDr Leeka I Kheifets World Health Organization

Is it safe?

“Still no conclusion….

“

“66

EMF & CANCER: EPIDEMIOLOGIC EVIDENCE TO DATEDr Leeka I Kheifets World Health Organization

Is it safe? How to quantify “possibly”?

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Is it safe?And then, number of scientific papers show health issues at EMF levels 1000 times lower from ICNIRP

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Bioinitiative report 2012Collection of 1000+ scientific papers

69http://www.bioinitiative.org/table-of-contents/

Why bother reducing EMF ?exposure?

• Lack of scientific consensus: Scientists are• Lack of scientific consensus: Scientists are divided, results are inconclusive, data is limited about long term EMF effects onlimited about long term EMF effects on humans.C ’t h t l & h d t• Can’t have a control group & hard to reproduce results.

• It is possible to significantly reduce one’s EMF exposure, without giving up technology or waiting until safety standards are changed.70

Prudent Avoidance

• Prudent avoidance is a precautionary principle in risk management, stating that reasonable efforts to minimise potential risks should be taken when the actual magnitude of the risks is unknown

• Needs to be low cost• Needs to be easy to implement

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Precautionary standards

• Precautionary Standards advocating prudent avoidance, minimizing our personal EMF exposure and maximizing the distance to EMF source (like using a seat belt in the car)

• For example: BUILDING BIOLOGY PRECAUTIONARY GUIDELINES (SBM-2008) For Sleeping Areas

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SBM-2008 limits

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SBM-2008 limits (cont)

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Strategies to reduce EMF exposure

• Move bed 3ft from outlets/extension cords• Use battery alarm clockUse battery alarm clock• Use LAN instead of WiFi or move the

router in the hallwayrouter in the hallway• Use speaker phone or air tube phone

h d theadset• Don’t put laptop on your lap when it is

plugged in AC75

Conclusion

• Scientific community is divided in the long term effects of EMF on humans

• Prudent avoidance suggests reducing EMF Exposure p

• Learn to recognize and measure EMF sourcessources

• Maximize the distance from the sourcesMi i i th f EMF• Minimize the use of EMF sources.

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