electro-magnetic field characterization and sources

7/29/2019 Electro-Magnetic Field Characterization and Sources

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Module 1.2 Non ionizing radiationIzmir, may 12th-13rd 2011

ELECTROMAGNETIC 0 Hz 300 GHz

Laura FILOSA

Field characterization & occupational exposure sources


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3. Electromagnetic field characterization

2. European frame introduction

4. Occupational emf sources

1. Organization of the NIR Module


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Artificial opticalradiation

AOR

TOMORROW, 13 MayTODAY, 12 May

ElectromagneticalFieldsEMF


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The object of this Directive is to introduce generalprinciples concerning the prevention of occupationalrisks, the protection of safety and health, the eliminationof risk and accident factors, the informing, consultation,balanced participation in accordance with national laws

and/or practices and training of workers and theirrepresentatives, as well as general guidelines for theimplementation of the said principles.

Council Directive 89/391/EEC of 12 June 1989 on theintroduction of measures to encourage improvements

in the safety and health of workers at work
http://../TURCHIA%20maggio%202011/1%20PRESENTAZIONE%201/Framework%20directive.ppt


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2002 2003 2004 2006


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2011 NEW EMF European Directive 2011 / XX / EC

COME INTO FORCE

2004 PASSING EMF DIRECTIVE

2008 AMENDMENT TO EMF DIRECTIVE

30/4/2010 Proposal of new directive to EU Council


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MAGNETIC RISONANCE

PROBLEMSRELATED TO SOMEINDUSTRIALAPPLICATIONS

Deadline postponed

DIFFICULT IMPLEMENTATION IN SME


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Protection of Workers Exposed to EMFin the European Union:

Directive 2004/40/EC

1. The philosophy behind?

2. Possible implementation problems?


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Electric and magnetic phenomena

Electric field Magneticfield

Is generated by(Every object on

which is present) anet electric charge

(Every conductor

on which is flowing)

an electric current

Is a region of space

where forces arepresent, which haveeffects on

(Other objects

possessing) netelectric charges

(Other conductors

on which areflowing) electriccurrents


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They link the field

quantities, their sourcesand the characteristics ofmaterials

The Maxwells system of

equations


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0

0

E

J

E

B

B

Electric and magneticfields are decoupled.

Electric and magnetic fieldsare due to materialsources:

Electric charge for theelectric field;

Electric current for themagnetic field.

The Maxwells system of equations

in quasi-static conditions

(static or extremely low frequency fields)


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Wavelenght

Frequency

Period T

Amplitude A


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Units of measurement and symbols

Quantity Unit of meas. Symbol

Frequency hertz f [Hz]

Wavelength meter [m]

*f = c (speed of light, approx. 3x108 m/s in vacuum and air)

Although biological effects of EM fields dramatically depend onfrequency, the frequency itself is not a direct measure of radiationintensity.

Safety standards and guidelines always specify limits which

depend on frequency in a complex way.

The wavelength is the reference to describe the structure of the EMfield as a function of distance from its source.


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Units of measurement and symbols

Quantity Unit of meas. Symbol

Electric field volt/meter E [V/m]

Magnetic field ampere/meter H [A/m]

Magnetic fluxdensity

tesla B [T]gauss (obsolete) B [G]

1 G = 100 T, 1 T = 10 mG, 1 T = 10000 G

1 A/m is approximately equivalent to 1,2 T

Power density watt/squaremeter S [W/m2]


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The structure of the EM field as afunction of distance from the source

CHARGE

VOLTAGE

CURRENT

ELECTRICFIELD

Decays as

1/d2

MAGNETICFIELD

Decays as

1/d2

SOURCE

ELECTRICFIELD

MAGNETICFIELD

1/d

ELECTRIC AND MAGNETIC

REACTIVE FIELDS

ELECTROMAGNETIC

RADIATIVE FIELDS

EM WAVE


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Quantisticenergy

Wavelenght

Frequency Frequencies bandsdefinition

Gamma rays, Cosmic rays

X Rays

Ultraviolet rays12 eV100 nm

Visible radiation

Infrared radiation

VLF, LF

MF, HF

VHF, UHF

EHF


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ATOMSIONIZING ENERGY

[ eV ] nm ]

ONLY STARTING FROM UV RADIATIONS

THERE IS THE CHANCE TO IONIZING THE

BIOLOGICAL MATTER

Caesium 3.9 318

Carbon 11.3 110

Hydrogen 13.6 91Oxygen 13.8 93

Azote 14.3 56

Helium 24.8 50


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Natural static

electric field


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130 V/m

100 V/m 20 kV/m

45 50 T

L d i di f


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Low and intermediate frequency sources

High frequency sources


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High frequency sources


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Main occupational EM sources


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Industrial EM heating: useful in productionprocessing requiring a fast and efficientheating (hardening and other metallurgictreatments, plastic welding and sealing, wood

gluing, food and wood sterilization, cooking,drying of ceramics).

Sanitary electromagnetic heating:marconi-therapy (short-wave diathermy),radar therapy (microwave).

Industrial and sanitary applicationsof EM heating


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up to 500 kV20 Kv / m

600 V

H < 30 V/m

10-500 kV/m


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DC SUPPLY derivedFrom alternating currentby rectification, so alsoAC harmonic

components can exist

< 100 mT

Electrolytic process

Permanent magnet


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< 0.1-30 T< 10 V/m


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OVERHEADTRANSMISSION

LINE

ELECTRIC

FIELDSTRENGTH

[kV / m]

MAGNETIC

FLUXDENSITY

T]

110 kV

240 kV400 kV765 kV

0.5 - 2

3 - 56 - 10

10 - 12

2 - 5

5 - 1010 - 1530 - 40

Depending on the line design and current, electric

and magnetic fields generally fall to background

strengths at distances of about 50-100 m
http://www.google.it/imgres?imgurl=http://www.power-technology.com/projects/mcnary-day/images/1-transmission-line.jpg&imgrefurl=http://www.power-technology.com/projects/mcnary-day/mcnary-day1.html&usg=__OanxgLzk97ZsxREGMHCHKsKJRxE=&h=600&w=400&sz=45&hl=it&start=19&zoom=1&itbs=1&tbnid=y00PITvit5RJGM:&tbnh=135&tbnw=90&prev=/search%3Fq%3DTRANSMISSION%2BLINE%26hl%3Dit%26biw%3D1259%26bih%3D867%26gbv%3D2%26tbm%3Disch&ei=CArETZ3oF8GaOo618IME


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ELECTRICFIELD

STRENGTH[kV / m]

MAGNETICFLUX

DENSITYT]

Control room

Power station

Substation

1.5

6

24

150

75

400

Exposure limit10 kV / m 500 T


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Only detect

1. 10Hz-20kHz2. 20-235 kHz3. 1-20 MHz4. 0.8-2.5 GHz

Detect and convey

information

1. Hz-500 kHz2. 2-30 MHz

3. 850-950MHz2.45 GHz5.8 GHz

manual gate

Examples of EAS RFID and MD systems
http://www.google.it/imgres?imgurl=http://www.edsuk.com/productImages/859.jpg&imgrefurl=http://www.edsuk.com/item.php%3Fid%3D116&usg=__Hlrg1rMAbVpN3_KZ9s1aBYP2s0U=&h=190&w=200&sz=41&hl=it&start=3&zoom=1&itbs=1&tbnid=YA9TfP4z57gr-M:&tbnh=99&tbnw=104&prev=/search%3Fq%3Delectronic%2Barticle%2Bsurveillance%26hl%3Dit%26biw%3D1259%26bih%3D867%26gbv%3D2%26tbm%3Disch&ei=Cf7DTd_vHNCZOtyg3PwDhttp://www.google.it/imgres?imgurl=http://www.edsuk.com/productImages/859.jpg&imgrefurl=http://www.edsuk.com/item.php%3Fid%3D116&usg=__Hlrg1rMAbVpN3_KZ9s1aBYP2s0U=&h=190&w=200&sz=41&hl=it&start=3&zoom=1&itbs=1&tbnid=YA9TfP4z57gr-M:&tbnh=99&tbnw=104&prev=/search%3Fq%3Delectronic%2Barticle%2Bsurveillance%26hl%3Dit%26biw%3D1259%26bih%3D867%26gbv%3D2%26tbm%3Disch&ei=Cf7DTd_vHNCZOtyg3PwDhttp://www.google.it/imgres?imgurl=http://www.edsuk.com/productImages/859.jpg&imgrefurl=http://www.edsuk.com/item.php%3Fid%3D116&usg=__Hlrg1rMAbVpN3_KZ9s1aBYP2s0U=&h=190&w=200&sz=41&hl=it&start=3&zoom=1&itbs=1&tbnid=YA9TfP4z57gr-M:&tbnh=99&tbnw=104&prev=/search%3Fq%3Delectronic%2Barticle%2Bsurveillance%26hl%3Dit%26biw%3D1259%26bih%3D867%26gbv%3D2%26tbm%3Disch&ei=Cf7DTd_vHNCZOtyg3PwDhttp://www.google.it/imgres?imgurl=http://www.edsuk.com/productImages/859.jpg&imgrefurl=http://www.edsuk.com/item.php%3Fid%3D116&usg=__Hlrg1rMAbVpN3_KZ9s1aBYP2s0U=&h=190&w=200&sz=41&hl=it&start=3&zoom=1&itbs=1&tbnid=YA9TfP4z57gr-M:&tbnh=99&tbnw=104&prev=/search%3Fq%3Delectronic%2Barticle%2Bsurveillance%26hl%3Dit%26biw%3D1259%26bih%3D867%26gbv%3D2%26tbm%3Disch&ei=Cf7DTd_vHNCZOtyg3PwDhttp://www.google.it/imgres?imgurl=http://www.edsuk.com/productImages/859.jpg&imgrefurl=http://www.edsuk.com/item.php%3Fid%3D116&usg=__Hlrg1rMAbVpN3_KZ9s1aBYP2s0U=&h=190&w=200&sz=41&hl=it&start=3&zoom=1&itbs=1&tbnid=YA9TfP4z57gr-M:&tbnh=99&tbnw=104&prev=/search%3Fq%3Delectronic%2Barticle%2Bsurveillance%26hl%3Dit%26biw%3D1259%26bih%3D867%26gbv%3D2%26tbm%3Disch&ei=Cf7DTd_vHNCZOtyg3PwDhttp://www.google.it/imgres?imgurl=http://www.edsuk.com/productImages/859.jpg&imgrefurl=http://www.edsuk.com/item.php%3Fid%3D116&usg=__Hlrg1rMAbVpN3_KZ9s1aBYP2s0U=&h=190&w=200&sz=41&hl=it&start=3&zoom=1&itbs=1&tbnid=YA9TfP4z57gr-M:&tbnh=99&tbnw=104&prev=/search%3Fq%3Delectronic%2Barticle%2Bsurveillance%26hl%3Dit%26biw%3D1259%26bih%3D867%26gbv%3D2%26tbm%3Disch&ei=Cf7DTd_vHNCZOtyg3PwD


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Examples of EAS, RFID and MD systems

System Frequency Comments

10 Hz 135 kHz1 - 20 MHz0.8 - 2.5 GHz

Anti-theft system in shopsAnti-theft system in shopsMicrowave EAS systems in shops

EAS

RFID

1 Hz 500 kHz

2 - 30 MHz850-950 MHz,2.45 GHz, 5.8 GHz

Access control, library systems,

item tracking Access control, smart cards Train monitoring, toll collection

systems

MD 0.24 8 kHz10 kHz- 2 MHz

Airport and prison control systemHandheld metal detectors


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Peak magnetic flux densities measured within EAS gates

FREQUENCY BPEAK[

REFERENCE

LEVEL

[ ]

Distance from

transmitter

[cm]

73 Hz

219 Hz230 Hz535.7 Hz5-7.5 kHz

58 kHz

146122937243

62-65

484161154664444

313642364836

Below 100 kHz, peak reference values for pulsed fields are obtained by multiplying

the rms-values by V2


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APPLIED TO HEAT WOOD(GLUE DRYERS) OR WELDPLASTIC (PLASTIC SEALERS)BY APPLYING A STRONG RFFIELD BETWEEN METAL

ELECTRODES.

Frequency range: 10-110 MHz

13.56 MHz27.12 MHz40.68 MHz


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PROCESS THAT

GENERATE HEATH USINGALTERNATING CURRENTFLOWING THROUGHLARGE COILS

FORGING, SURFACEHARDENING,BENDING PIPES

INDUCTION FURNACES ARE THE MOST POWERFULSOURCES OF MAGNETIC FIELDS IN INDUSTRY

50 Hz 8 MHz
http://www.google.it/imgres?imgurl=http://www.ews-konnerth.at/img/him/induction-heating-chart.gif&imgrefurl=http://www.ews-konnerth.at/en/himmelwerk/&usg=__5osBvEmdJNIYz71bOEbitHwpxBE=&h=198&w=325&sz=28&hl=it&start=7&zoom=1&itbs=1&tbnid=fKsXiWvz8k3znM:&tbnh=72&tbnw=118&prev=/search%3Fq%3Dinduction%2Bheating%26hl%3Dit%26biw%3D1259%26bih%3D867%26gbv%3D2%26tbm%3Disch&ei=rhTETaHfKceBOsTJ8PQD


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INDUSTRIALLY USED

FOR DRYING OFWATER DAMAGES IN

FLOOR OR WALLS

915 MHz2450 MHz

Power density of MW radiation is HIGH

and furthermore presence of stray fields


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GASWELDING

LASERWELDING

ELECTRICWELDING


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ELECTRIC ARC WELDINGPROCESSES ARE USED TOFUSE METAL PIECESTOGETHER

ACCORDING THE TYPES OF WELDING PROCESS(ARC, RESISTANCE, HIGHER FREQUENCY, ELECTRON BEAM

WELDING) ACTION VALUES COULD BE EXCEEDED
http://www.google.it/imgres?imgurl=http://www.sambellwelding.com/welding.jpg&imgrefurl=http://www.sambellwelding.com/links.htm&usg=__p-W9xNeiLEp6ih7WGrKTdCzRxDw=&h=1993&w=1960&sz=164&hl=it&start=16&zoom=1&um=1&itbs=1&tbnid=HypHe4taZZK3mM:&tbnh=150&tbnw=148&prev=/search%3Fq%3Delectric%2Bwelding%26um%3D1%26hl%3Dit%26sa%3DN%26biw%3D1259%26bih%3D867%26tbm%3Disch&ei=pxjETYerAYOCOvGysYcE


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EXAMPLES ARE THE ELECTROLYSIS OFBRINE TO PRODUCE CHLORINE GAS ANDCAUSTIC SODA&THE EXTRACTION OF METALS SUCH ASZINC, CADMIUM, AND ALLUMINIUM FROMORES DISSOLVED IN WATER AND ACID

SOLUTIONS&SURFACE TREATMENT (ZINC COATING,CHROMIUM PLATING)Three environments in

which workers may be

exposed to strongmagnetic field:

Transformer rectifier roomBus barElectrolysis hall


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Physioterapic use of diathermy

Surgical diathermy

Magnetic Resonance Imaging

MAINLY THERE ARE THREEAPPLICATION IN MEDICINE OFINTEREST:


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Physiotherapist using a pulsedshortwave diathermy devicefor pain relief

IN MEDICAL CLINICS RFARE USED IN

PHYSIOTHERAPY INSHORTWAVE ORMICROWAVE DIATHERMYTREATMENT

APPLICATION ARE OPENAND POSSIBLEOVEREXPOSURE OFSTAFF CAN OCCURE

SHORTWAVE 27 MHzMICROWAVE 2.45 GHz


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RF ENERGY IS USED TOCUT AND TO COAGULATE,AND SINCE UNSHIELDEDELECTRODES ARE USEDTHE FIELD ARE RATHER

INTENSE AND SPECIALATTENTION IS NEEDED TOENSURE COMPLIANCEWITH DIRECTIVE ON

OCCUPATIONALEXPOSURE


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STATIC MAGNETICFIELD

RF FIELDS

GRADIENTMAGNETICFIELDS


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LET CONSIDER 3 GROUPS:

1. TWO-WAY COMMUNICATION TRANSMITTERS2. ONE-WAY BROADCASTING TRANSMITTERS3. RADARS


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Mobile telephony: GSM and UMTS base stationsTETRA transmitters

GSM telephonesUMTS telephonesTETRA hand portable & vehicle-

mounted transmitters

Wireless communication: WLLbeam transmitters

broadcastingRadar


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ANTENNAS OF BROADCASTRADIO & TV STATIONS ARE THE

MOST POWERFUL SOURCES OFENERGY INTENTIONALLYRADIATED INTO AIR


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DESIGNATION FREQUENCYRANGE

APPLICATION

LF (long)

MF (medium)

HF (short)

VHF

UHF

30-300 kHz

300-3000 kHz

3-30 MHz

30-300 MHz

0.3-3 GHz

AM radio transmitters



FM radio transmitters

Television transmitters

Frequency bands for broadcast radio and TV transmitters


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electro-magnetic field characterization and sources

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