1、BRITISH STANDARDBS EN50421:2006Product 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) The European Standard EN 50421:2006 has t
2、he status of a British StandardICS 13.280g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 50421:2006This British Standard was published under t
3、he authority of the Standards Policy and Strategy Committee on 31 July 2006 BSI 2006ISBN 0 580 48953 1National forewordThis British Standard is the official English language version of EN 50421:2006. The UK participation in its preparation was entrusted to Technical Committee GEL/106, Human exposure
4、 to lf and hf electromagnetic radiation, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be
5、 found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are r
6、esponsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and ke
7、ep UK interests informed; monitor related international and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page, pages 2 to 9 and a back cover.The BSI copyright notice displayed in this document indicates
8、 when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARD EN 50421 NORME EUROPENNE EUROPISCHE NORM June 2006 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elek
9、trotechnische 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 50421:2006 E ICS 13.280 English version Product standard to demonstrate the compliance of stand
10、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) Norme produit pour dmontrer la conformit des metteurs de radiodiffusion isols par rapport aux niveaux de rfrence ou aux restri
11、ctions de base relatifs lexposition du public aux champs lectromagntiques (30 MHz - 40 GHz) Produktnorm zum Nachweis der bereinstimmung von einzelnen Rundfunksendern mit den Referenzwerten oder den Basisgrenzwerten bezglich der Exposition der Allgemeinbevlkerung gegenber hochfrequenten elektromagnet
12、ischen Feldern (30 MHz 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
13、-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
14、 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, G
15、ermany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN 50421:2006 - 2 - Foreword This European Standard was prepared by Technical Committee C
16、ENELEC 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 50421 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 iden
17、tical 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 _ - 3 - EN 50421:2006 Contents 1 Scope.4 2 Normative references 4 3 Physical quantities, units and constants4 4 Definitions 4 5 Conditi
18、ons for calculation and measurement 6 6 Limits6 7 Evaluation of results and determination of compliance .7 8 Documentation provided by the equipment manufacturer.7 Annex A (informative) Declaration of conformity8 Annex B (informative) A-deviations 9 EN 50421:2006 - 4 - 1 Scope This product standard
19、applies to fixed stand alone broadcast transmitter operating in the frequency range 30 MHz to 40 GHz when put on the market. The term broadcast transmitter covers fixed stand alone broadcast transmitters intended for use with external antennas of the same or an other manufacturer. The object of this
20、 standard is to demonstrate the compliance of such equipment with the reference levels or the basic restrictions related to public exposure to radio frequency electromagnetic fields. 2 Normative references The following referenced documents are indispensable for the application of this document. For
21、 dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 50420, Basic standard for the calculation and measurement of human exposure to electromagnetic fields from stand alone broadcast transmitter
22、s (30 MHz 40 GHz) 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) 3 Physical quantities, units and constants Physical quantities, units and constants are define
23、d in EN 50420. 4 Definitions For the purposes of this document, the following terms and definitions apply. 4.1 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
24、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 4.2 broadcasting service radiocommunication service in which the transmissions are intended for direct reception by the general public. This service may
25、 include sound transmissions, television transmissions or other types of transmission 4.3 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 d
26、o 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 4.4 conductivity ( ) ratio of the conduction-current density in a medium to the electric field strength. Conductivity is ex
27、pressed in units of siemens per metre (S/m) - 5 - EN 50421:2006 4.5 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 cant be time-
28、averaged 4.6 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) 4.7 induced current current circulating inside a human bod
29、y resulting directly from an exposure to an electromagnetic field 4.8 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 H)(2) Magnetic field strength is expressed in units of ampere per metre (A/m) 4.9 m
30、odulation 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
31、are being exceeded 4.10 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) 4.11 reference antenna type of antenna specified in basic standard for each type of service 4.12 re
32、ference level 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 necessar
33、ily 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
34、and contact currents 4.13 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 EN 50421:2006 - 6 - 4.14 specific absorption rate (SAR) the time derivative of the incremental ele
35、ctromagnetic energy (dW) absorbed by (dissipated in) an incremental mass (dm) contained in a volume element (dV) of given mass density () WWSARtm t V=dd d ddd d d(3) SAR is expressed in units of watts per kilogram (W/kg). NOTE SAR can be calculated by ESAR=2i(4) 0=tidtdTcSAR(5) where Ei: r.m.s. valu
36、e of the electric field strength in the tissue in V/m, : conductivity of body tissue in S/m, : density of body tissue in kg/m3, ci: specific heat capacity of body tissue in J/kg K, ddTt: time derivative of temperature in body tissue in K/s. 4.15 transmitter device to generate radio frequency power f
37、or the purpose of communication but on its own is not intended to radiate it 5 Conditions for calculation and measurement The calculation and/or measurement shall be performed in accordance with EN 50420. The transmitter shall be operating in accordance with the manufacturer specification. Calculati
38、ons and/or measurements on broadcast transmitters intended for use with external antennas shall be performed for one reference configuration consisting of a combination of the broadcast transmitter and an antenna system representative of the intended final use. The distances from the radiating anten
39、na at which the calculations and/or measurements shall be performed, shall be the compliance distances for general public as specified by the transmitter equipment manufacturer. 6 Limits The transmitter shall comply with the relevant limits for public specified as basic restrictions in Council Recom
40、mendation for the general public exposure 1999/519/EC (see Clause 2). 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 exc
41、eeded. 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. - 7 - EN 50421:2006 7 Evaluation of results and determination of compliance If the r.m.s. power averag
42、ed over 6 min emitted by the broadcast transmitter is less than or equal to 20 mW then the transmitter is deemed to comply without testing. If the r.m.s. power averaged over 6 min emitted by the transmitter is more than 20 mW, then E, H, induced current or SAR calculations and/or measurements shall
43、be performed according to Clause 5. The results of calculations and/or measurements shall be compared directly to the limits. The equipment is deemed to fulfil the requirements of this standard if the calculated and/or measured values are less than or equal to the limits at the compliance distances.
44、 NOTE A possibility to deal with uncertainty is to use typical uncertainties of the basic standard 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. 8 Documentati
45、on provided by the equipment manufacturer The manufacturer shall provide the following information with the equipment: a) output power, b) type of modulation of the transmitter, c) compliance distances for general public exposure, and, if appropriate, d) information on how to determine exposure leve
46、ls and compliance distances for any optional system configuration not specified in detail in the basic standard. EN 50421:2006 - 8 - Annex A (informative) Declaration of conformity This declaration can be used as a uniform way of giving information of compliance to interested parties. Information to
47、 whom it may concern Dlaration of conformity with EN 50421 The manufacturer, or representative, hereby certifies that the equipment is in full compliance with the requirements of this standard, when connected to the reference antenna, at the distances of at which the calculations and/or measurements
48、 have been performed. Special operating conditions: Other relevant information: Date: _ Signature: _ - 9 - EN 50421:2006 Annex B (informative) A-deviations A-deviation: National deviation due to regulations, the alteration of which is for the time being outside the competence of the CENELEC national
49、 member. This European Standard does not fall under any Directive of the EC. In the relevant CENELEC countries these A-deviations are valid instead of the provisions of the European Standard until they have been removed. Clause Deviation General Switzerland (Ordinance relating to Protection from Non-Ionising Radiation, SR 814.710 of 23 December 1999 (as of 1 February 2000) This product standard must not be applied to installations which are covered by the Ordinance relati
