Basic standard for the evaluation of human exposure to electromagnetic fields from a stand alone broadcast transmitter (30 MHz - 40 GHz)

This standard applies to a broadcast transmitter operating in the frequency range 30 MHz to 40 GHz when put on the market. The objective of the standard is to specify, for such equipment operating in typical conditions, the method for assessment of compliance distances according to the basic restrictions (directly or indirectly via compliance with reference levels) related to human exposure to radio frequency electromagnetic fields.

Grundnorm für die Berechnung und Messung der Exposition von Personen gegenüber elektromagnetischen Feldern von einzelnen Rundfunksendern (30 MHz bis 40 GHz)

Diese Norm gilt für einzelne Rundfunksender, die im Frequenzbereich 30 MHz bis 40 GHz betrieben werden, wenn sie in Verkehr gebracht werden. Zweck dieser Norm ist, für die unter typischen Betriebsbedingungen betriebenen Geräte und Einrichtungen das Verfahren zur Bewertung der Konformitätsabstände (entweder durch direkten Nachweis oder indirekt durch den Nachweis der Einhaltung von Referenzwerten) zu den auf die Sicherheit von Personen in hochfrequenten elektromagnetischen Feldern bezogenen Basisgrenzwerten festzulegen.

Norme pour le calcul et la mesure de l'exposition des personnes aux champs électromagnétiques provenant des émetteurs de radiodiffusion isolés (30 MHz - 40 GHz)

Cette norme s’applique aux émetteurs de radiodiffusion isolés fonctionnant dans la gamme de fréquence de 30 MHz à 40 GHz. Le but de cette norme est de spécifier, pour de tels équipements fonctionnant dans des conditions typiques, la méthode d’évaluation des distances de conformité relatives aux restrictions de bases (directement ou indirectement via la conformité aux niveaux de référence) liées à l’exposition du corps humain aux champs magnétiques de fréquences radio.

Osnovni standard za ocenjevanje izpostavljenosti ljudi elektromagnetnim sevanjem samostojnih oddajnikov (30 MHz–40 GHz)

General Information

Status
Published
Publication Date
30-Nov-2006
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Dec-2006
Due Date
01-Dec-2006
Completion Date
01-Dec-2006

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Osnovni standard za ocenjevanje izpostavljenosti ljudi elektromagnetnim sevanjem samostojnih oddajnikov (30 MHz–40 GHz)Grundnorm für die Berechnung und Messung der Exposition von Personen gegenüber elektromagnetischen Feldern von einzelnen Rundfunksendern (30 MHz bis 40 GHz)Norme pour le calcul et la mesure de l'exposition des personnes aux champs électromagnétiques provenant des émetteurs de radiodiffusion isolés (30 MHz - 40 GHz)Basic standard for the evaluation of human exposure to electromagnetic fields from a stand alone broadcast transmitter (30 MHz - 40 GHz)17.240Merjenje sevanjaRadiation measurements13.280Varstvo pred sevanjemRadiation protectionICS:Ta slovenski standard je istoveten z:EN 50420:2006SIST EN 50420:2006en01-december-2006SIST EN 50420:2006SLOVENSKI

STANDARD
SIST EN 50420:2006
EUROPEAN STANDARD EN 50420 NORME EUROPÉENNE
EUROPÄISCHE NORM June 2006

CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2006 CENELEC -

All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 50420:2006 E
ICS 13.280
English version
Basic standard for the evaluation of human exposure to
electromagnetic fields from a stand alone broadcast transmitter
(30 MHz - 40 GHz)
Norme pour le calcul et la mesure de l'exposition des personnes aux
champs électromagnétiques provenant des émetteurs de radiodiffusion isolés
(30 MHz - 40 GHz)

Grundnorm für die Berechnung und Messung der Exposition von Personen gegenüber elektromagnetischen Feldern von einzelnen Rundfunksendern

(30MHz bis 40 GHz)

This European Standard was approved by CENELEC on 2005-12-06. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.

SIST EN 50420:2006
EN 50420:2006 - 2 - Foreword

This European Standard was prepared by Technical Committee CENELEC TC 106X, Electromagnetic fields in the human environment.

The text of the draft was submitted to the formal vote and was approved by CENELEC as EN 50420 on 2005-12-06. The following dates were fixed: – latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement

(dop)

2007-01-01 – latest date by which the national standards conflicting with the EN have to be withdrawn

(dow)
2009-01-01 __________ SIST EN 50420:2006

- 3 - EN 50420:2006 Contents 1 Scope.....................................................................................................................................................4 2 Normative references............................................................................................................................4 3 Physical quantities, units and constants................................................................................................5 3.1 Quantities.....................................................................................................................................5 3.2 Constants.....................................................................................................................................5 4 Terms and definitions............................................................................................................................5 5 Applicability of compliance assessment methods.................................................................................9 5.1 Introduction..................................................................................................................................9 5.2 Assessment procedure................................................................................................................9 5.3 Representative antennas for each service................................................................................11 6 SAR measurement and calculation.....................................................................................................11 6.1 Whole-body SAR implicit compliance........................................................................................11 6.2 SAR compliance........................................................................................................................11 7 Electromagnetic field measurement....................................................................................................11 7.1 Measurement.............................................................................................................................11 7.2 Uncertainty................................................................................................................................12 8 Electromagnetic field calculation.........................................................................................................15 8.1 Field regions..............................................................................................................................15 8.2 Calculation models....................................................................................................................16 9 Contact currents measurement and calculation..................................................................................17 10 Induced current measurement and calculation....................................................................................17 Annex A (normative)

Field volume measurement......................................................................................18 Annex B (informative)

Compliance boundary examples............................................................................21

Figure 1 – Alternative routes to calculate E-field, H-field values at point of investigation..........................15 Figure A.1 – Block diagram of the EUT measurement system..................................................................18 Figure A.2 – Cylindrical, cartesian and spherical co-ordinates defined relative to the EUT......................19

Table 1 – Applicable methods for each antenna region.............................................................................10 Table 2 – Representative antennas for each service.................................................................................11 Table 3 – Recommended parameters .......................................................................................................12 Table 4 – Representative antennas for each service.................................................................................14 Table B.1 – Compliance boundary examples.............................................................................................22 SIST EN 50420:2006

EN 50420:2006 - 4 - 1 Scope This standard applies to a broadcast transmitter operating in the frequency range 30 MHz to 40 GHz when put on the market.

The objective of the standard is to specify, for such equipment operating in typical conditions, the method for assessment of compliance distances according to the basic restrictions (directly or indirectly via compliance with reference levels) related to human exposure to radio frequency electromagnetic fields. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

Council Recommendation 1999/519/EC of 12 July 1999 on the limitation of exposure of the general public to electromagnetic fields (0 Hz to 300 GHz) (Official Journal L 199 of 30 July 1999)

EN 504131), Basic standard on measurement and calculation procedures for human exposure to electric, magnetic and electromagnetic fields (0 Hz - 300 GHz)

EN 50421, Product standard to demonstrate the compliance of stand alone broadcast transmitters with the reference levels or the basic restrictions related to public human exposure to radio frequency electromagnetic fields (30 MHz - 40 GHz)

EN 55016-4-2, Specification for radio disturbance and immunity measuring apparatus and methods – Part 4-2: Uncertainties, statistics and limit modelling – Uncertainty in EMC measurements (CISPR 16-4-2)

EN ISO/IEC 17025:2000, General requirements for the competence of testing and calibration laboratories (ISO/IEC 17025:1999)

European Commission Enterprise Directorate General Standardisation Mandate addressed to CEN, CENELEC, and ETSI in the field of electro-technology, information technology and telecommunications M/305 Brussels

IEEE Std C95.1:1999, IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz

International Commission on Non-Ionizing Radiation Protection, Guidelines for Limiting Exposure to Time-Varying Electric, Magnetic, and Electromagnetic Fields (up to 300 GHz), Health Physics Vol. 74, No 4, pp 494-522, 1998

ISO Guide to the expression of uncertainty in measurement, 1995
1) At draft stage. SIST EN 50420:2006
- 5 - EN 50420:2006

3 Physical quantities, units and constants 3.1 Quantities The internationally accepted SI-units are used throughout the standard.

Quantity Symbol Unit Dimensions Current density J ampere per square metre A/m² Electric field strength E volt per metre V/m Electric flux density D coulomb per square metre C/m² Electric conductivity σ siemens per metre S/m Frequency f hertz Hz Magnetic field strength H ampere per metre A/m Magnetic flux density B tesla (Vs/m²) T Mass density ρ kilo per cubic metre kg/m³ Permeability µ henry per metre H/m Permittivity ε farad per metre F/m Specific absorption rate

SAR watt per kilogram W/kg Wavelength λ metre m Temperature T kelvin K 3.2 Constants Physical constant

Magnitude
Speed of light in a vacuum
c 2,997 x 108 m/s
Permittivity of free space ε0 8,854 x 10-12 F/m
Permeability of free space µ0 4 π x 10-7 H/m
Impedance of free space 0η 120 π (approx. 377) Ω

4 Terms and definitions For the purposes of this document, the following terms and definitions apply.

4.1 antenna device that serves as a transducer between a guided wave (e.g. coaxial cable) and a free space wave, or vice versa 4.2 basic restriction restrictions on exposure to time-varying electric, magnetic, and electromagnetic fields that are based directly on established health effects. In the frequency range from 30 MHz to 10 GHz, the physical quantity used is the specific absorption rate. Between 10 GHz and 40 GHz, the physical quantity is the power density SIST EN 50420:2006

EN 50420:2006 - 6 - 4.3 broadcasting service radiocommunication service in which the transmissions are intended for direct reception by the general public. This service may include sound transmissions, television transmissions or other types of transmission 4.4 compliance distance minimum distance from the antenna where a point of investigation is deemed to be compliant. The set of compliance distances therefore defines the boundary outside which the exposure levels do not exceed the basic restrictions irrespective of the time of exposure. The distances are measured related to the nearest point of the antenna in each investigation direction 4.5 conductivity (σ) ratio of the conduction-current density in a medium to the electric field strength. Conductivity is expressed in units of siemens per metre (S/m) 4.6 contact current current produced in the body involved by human contact with metallic objects in the field. Shocks and burns can be the adverse indirect effects . Contact current relates to an instantaneous effect and so can't be time-averaged 4.7 electric field strength (E) magnitude of a field vector at a point that represents the force (F) on a positive small charge (q) divided by the charge E=Fq (1) Electric field strength is expressed in units of volt per metre (V/m) 4.8 electric flux density (D) magnitude of a field vector that is equal to the electric field strength (E) multiplied by the permittivity (ε) D=εE (2) Electric flux density is expressed in units of coulomb per square metre (C/m²) 4.9 equipment under test (EUT) device (such as transmitter, base station or antenna as appropriate) that is the subject of the specific test investigation being described 4.10 induced current currents circulating inside a human body resulting directly from an exposure to an electromagnetic field 4.11 intrinsic impedance (of free space 0η) η ratio of the electric field strength to the magnetic field strength of a propagating electromagnetic wave. The intrinsic impedance of a plane wave in free space is 120 π (approximately 377) Ω SIST EN 50420:2006

- 7 - EN 50420:2006 4.12 isotropy e.g., of a hypothetical receiving or transmitting antenna is, having equal intensities in all directions. Deviations of isotropy have to be considered at all measured values of EMF with regard to various angles of incidence and polarization of the measured field In this document it is defined for incidences covering a hemisphere centred at the tip of the probe, with an equatorial plane normal to the probe and expanding outside the probe. The axial isotropy is defined by the maximum deviation of the measured quantity when rotating the probe along its main axis with the probe exposed to a reference wave with normal incidence with regard to the axis of the probe. The hemispherical isotropy is defined by the maximum deviation of the measured quantity when rotating the probe along its main axis with the probe exposed to a reference wave with varying angles of incidences and polarisation with regard to the axis of the probe in the half space in front of the probe 4.13 linearity e.g. of an antenna or any other technical device is showed, when all relationships between a reference quantity and the deviations of this quantity lie along a straight line. The maximum deviation over the measurement range of the measured quantity value from the closest linear reference curve defined over a given interval has to be taken into account in measurement procedures 4.14 magnetic field strength (H) magnitude of a field vector in a point that results in a force (F) on a charge q moving with the velocity v F=q(v×µH) (3) The magnetic field strength is expressed in units of ampere per metre (A/m) 4.15 magnetic flux density (B) magnitude of a field vector that is equal to the magnetic field strength H multiplied by the permeability (µ)of the medium B=µH (4) Magnetic flux density is expressed in units of tesla (T) 4.16 modulation process, or the result of the process, where some characteristic of the wave (amplitude, frequency or phase) is varied in accordance with another wave or signal. It must also be taken into consideration when carrying out measurements and calculations to determine whether or not the limits are being exceeded 4.17 permeability (µ) magnetic permeability of a material defined by the magnetic flux density B divided by the magnetic field strength H: µ=BH, (5) where µ is the permeability of the medium expressed in henry per metre (H/m) SIST EN 50420:2006

EN 50420:2006 - 8 - 4.18 permittivity (ε) property of a dielectric material (e.g., biological tissue) defined by the electrical flux density D divided by the electrical field strength E ε=DE (6) The permittivity is expressed in units of farad per metre (F/m) 4.19 point of investigation (PI) location in space at which the value of E-field, H-field, Power flux density or SAR is evaluated. This location is defined in cartesian, cylindrical or spherical co-ordinates relative to the reference point on the EUT 4.20 power density (S) radiant power incident perpendicular to a surface, divided by the area of the surface. The power density is expressed in units of watt per square metre (W/m²) 4.21 reference levels reference levels of exposure are provided for comparison with measured values of physical quantities; compliance with all reference levels given in these guidelines will ensure compliance with basic restrictions. If measured values are higher than reference levels, it does not necessarily follow that the basic restrictions have been exceeded, but a more detailed analysis is necessary to assess compliance with the basic restrictions.

In the frequency range 30 MHz to 40 GHz the reference levels are expressed as electric field strength, magnetic field strength, power density values and contact currents 4.22 relative permittivity (εr) ratio of the permittivity of a dielectric material to the permittivity of free space i.e.: 0εεε=r (7) 4.23 root-mean-square (r.m.s.) the r.m.s. value is obtained by taking the square root of the average of the square of the value of the periodic function taken throughout one period 4.24 specific absorption rate (SAR) time derivative of the incremental energy (dW) absorbed by (dissipated in) an incremental mass (dm) contained in a volume element (dV) of given mass density (ρ)

SAR=ddtdWdm    =ddtdWρdV     
(8)
SAR is expressed in units of watt per kilogram (W/kg) SIST EN 50420:2006
- 9 - EN 50420:2006 NOTE SAR can be calculated by:
SAR=σEi2ρ (9)
SAR=cidTdt(t=0)

(10) where Ei is the r.m.s. value of the electric field strength in the tissue in V/m; σ is the conductivity of body tissue in S/m; ρ is the density of body tissue in kg/m³; ci is the heat capacity of body tissue in J/kg K; dTdt is the time derivative of temperature in body tissue in K/s. 4.25 transmitter device to generate radio frequency power for the purpose of communication but on its own is not intended to radiate it 5 Applicability of compliance assessment methods 5.1 Introduction Guidelines and recommended limits on human exposure to radio waves give basic restrictions in terms of SAR (below 10 GHz) or power flux density (above 10 GHz) and also reference levels in terms of contact current (between 30 MHz and 110 MHz) and field strengths or power density.

The compliance boundary defines the volume outside which the exposure levels do not exceed the basic restrictions irrespective of the time of exposure for the specific operating conditions of the broadcast transmitter. The compliance boundary is determined via a procedure where sufficient points of investigation are assessed.

It is technically possible to determine the compliance distance through measurements or calculations of SAR or electromagnetic fields relating to basic restrictions or reference levels, since compliance to the reference levels guarantees compliance to the basic restrictions.

Where the assessment is made through SAR, it should be noted that both localised and whole-body basic restrictions must be considered. Spatial averaging may be used with field strength assessments in order to assess whole-body SAR. 5.2 Assessment procedure 5.2.1 Methods This standard describes measurement and calculation methods that may be used to establish the compliance distances. SIST EN 50420:2006

EN 50420:2006 - 10 - Table 1 – Applicable methods for each antenna region
Applicable methods for each antenna region a to d

Reactive near-field Radiating near-field Far-field Basic restriction evaluation SAR or power density evaluation (calculation or measurement) – Clause 6 b Reference level calculation

E-field and H-field calculation – Clause 8

Induced currents calculation – Clause 10 c E-field or H-field calculation – Clause 8 Induced currents calculation Clause 10 c Reference level measurement

E and H field measurement Clause 7 d Induced currents measurement Clause 10 c E or H field measurement Clause 7 d Induced currents measurement Clause 10 c E-field or H-field measurementClause 7 d Induced currents measurement Clause 10 c a Compliance with the reference level will ensure compliance with the relevant basic restriction. If the measured or calculated value exceeds the reference level, it does not necessarily follow that the basic restriction will be exceeded. However, whenever a reference level is exceeded, it is necessary to test compliance with the relevant basic restriction and to determine whether additional protective measures are necessary. b In the frequency range from 30 MHz to 10 GHz, the physical quantity used is the specific absorption rate. Between 10 GHz and 40 GHz, the physical quantity is the power density. SAR calculation is the reference since it takes into account the fine structure of the head/body whereas the measurement methodology is based on a simplified phantom approximation.

c Only for frequencies between 30 MHz and 110 MHz. d Due to the existing probes on the market, above 2,5

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