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1、Determination of workers exposure to electromagnetic fields and assessment of risk at a broadcast site BS EN 50496:2008 raising standards worldwide NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BSI British Standards Licensed CopyChinese University of Hong Kong, 11/04/2009 07
2、:41, Uncontrolled Copy, (c) BSI National foreword This British Standard is the UK implementation of EN 50496:2008. The UK participation in its preparation was entrusted to Technical Committee GEL/106, Human exposure to low frequency and high frequency electromag- netic radiation. A list of organizat
3、ions represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. BSI 2008 ISBN 978 0 580 57861 8 ICS 17.240 BRITISH STANDARDBS EN 50496:2008 Comp
4、liance with a British Standard cannot confer immunity from legal obligations. This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2009 Amendments issued since publication Amd. No. Date Text affected Licensed CopyChinese University of Hon
5、g Kong, 11/04/2009 07:41, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD EN 50496 NORME EUROPENNE EUROPISCHE NORM November 2008 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secre
6、tariat: rue de Stassart 35, B - 1050 Brussels 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 50496:2008 E ICS 17.240 English version Determination of workers exposure to electromagnetic fields and assessment of risk at a bro
7、adcast site Dtermination de lexposition des travailleurs aux champs lectromagntiques et valuation des risques sur un site de radiodiffusion Ermittlung der Exposition von Arbeitnehmern gegenber elektromagnetischen Feldern und Bewertung des Risikos am Standort eines Rundfunksenders This European Stand
8、ard was approved by CENELEC on 2008-09-01. 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 concerni
9、ng 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
10、 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, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, I
11、taly, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 50496:2008 Licensed CopyChinese University of Hong Kong, 11/04/2009 07:41, Uncontrolled Copy, (c) BSI EN 50496:2008 - 2 - Forew
12、ord This European Standard was prepared by the 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 50496 on 2008-09-01. The following dates were fixed: latest date by which the
13、EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2009-09-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2011-09-01 _ BS EN 50496:2008 Licensed CopyChinese University of Hong Kong, 11
14、/04/2009 07:41, Uncontrolled Copy, (c) BSI - 3 - EN 50496:2008 Contents 1 Scope . 4 2 Normative references. 4 3 Terms and definitions 5 4 Assessment methods 6 4.1 Worker exposure assessment . 6 4.2 Use of public exposure assessment . 6 4.3 Assessment after technical modification . 7 5 Collection of
15、technical data 7 6 Determination of exposure levels by calculation or measurement 7 6.1 Methodologies . 7 6.2 Additional considerations 8 6.3 Determination process 10 7 Zoning of exposure work place 11 8 Checking of operating procedures in the different exposure work places12 8.1 Work place access c
16、onditions .12 8.2 Signage and delimitation .12 8.3 Specific documentation 13 8.4 Personal protective equipment 13 8.5 Safety instructions 13 8.6 Maintenance work 13 8.7 Inspections .14 8.8 Active implantable medical devices .14 9 Information and training 14 9.1 Information for workers 14 9.2 Trainin
17、g of workers 15 10 Assessment report .15 Annex A (normative) Summation formulae .16 Annex B (informative) Marking .19 Bibliography 20 Figures Figure 1 - Work place assessment process 11 Figure B.1 - Presence of electromagnetic field sources 19 BS EN 50496:2008 Licensed CopyChinese University of Hong
18、 Kong, 11/04/2009 07:41, Uncontrolled Copy, (c) BSI EN 50496:2008 - 4 - 1 Scope The object of this standard is to provide methods for assessing compliance with the requirements of the Directive 2004/40/EC 8 at a site operating one or more broadcast transmitters. This standard covers the frequency ra
19、nge up to 40 GHz. NOTE The Council and European Parliament Directive 2004/40/EC will be transposed into national legislation in all the EU member countries. It is recommended that users of this standard consult the national legislation related to this transposition in order to identify the national
20、regulations and requirements. These national regulations and requirements may have additional requirements that are not covered by this standard. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition c
21、ited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. 1 EN 50413, Basic standard on measurement and calculation procedures for human exposure to electric, magnetic and electromagnetic fields (0 Hz - 300 GHz) 2 EN 50420, Basic standard
22、 for the evaluation of human exposure to electromagnetic fields from a stand alone broadcast transmitter (30 MHz - 40 GHz) 3 EN 50475, Basic standard for the calculation and the measurement of human exposure to electromagnetic fields from broadcasting service transmitters in the HF bands (3 MHz - 30
23、 MHz) 4 EN 50499, Procedure for the assessment of the exposure of workers to electromagnetic fields 5 EN 62226-2-1, Exposure to electric or magnetic fields in the low and intermediate frequency range - Methods for calculating the current density and internal electric field induced in the human body
24、- Part 2-1: Exposure to magnetic fields - 2D models (IEC 62226-2-1) 6 IEEE C95.3, Recommended Practice for Measurements and Computations of Radio Frequency Electromagnetic Fields With Respect to Human Exposure to Such Fields 7 Council Recommendation 1999/519/EC of 12 July 1999 on the limitation of e
25、xposure of the general public to electromagnetic fields (0 Hz to 300 GHz) (Official Journal L 199 of 30 July 1999) 8 Directive 2004/40/EC of the Parliament and of the Council on the minimum health and safety requirements regarding the exposure of workers to the risks arising from physical agents (El
26、ectromagnetic fields) Official Journal of 30 April 2004 9 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 BS EN 50496:2008 Li
27、censed CopyChinese University of Hong Kong, 11/04/2009 07:41, Uncontrolled Copy, (c) BSI - 5 - EN 50496:2008 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 action values the magnitude of directly measurable parameters, provided in terms of e
28、lectric field strength (E), magnetic field strength (H), magnetic flux density (B), power density (Seq), limb induced current (IL) and contact current (IC) at which one or more of the specified measures in 8 must be undertaken. Compliance with these values will ensure compliance with the relevant ex
29、posure limit values of 8 3.2 AIMD Active Implantable Medical Device 3.3 antenna device that serves as a transducer between a guided wave (e.g. coaxial cable) and a free space wave, or vice versa 3.4 near-field region region generally in proximity to an antenna or other radiating structure, in which
30、the electric and magnetic fields do not have a substantially plane-wave character, but vary considerably from point to point. The near-field region is further subdivided into the reactive near-field region, which is closest to the radiating structure and that contains most or nearly all of the store
31、d energy, and the radiating near- field region where the radiation field predominates over the reactive field, but lacks substantial plane- wave character and is complicated in structure 3.5 broadcasting service radiocommunication service in which the transmissions are intended for direct reception
32、by the general public. This service may include sound transmissions, television transmissions or other types of transmission e.g. data 3.6 broadcast site site operating one or more broadcast transmitters 3.7 contact current current flowing into the body resulting from contact with a conductive objec
33、t in an electromagnetic field. This is the localised current flow into the body (usually the hand, for a light brushing contact). Shocks and burns can be the adverse indirect effects. Contact current relates to a short term effect and cannot be time-averaged 3.8 induced current current flowing insid
34、e a human body resulting directly from an exposure to an electromagnetic field 3.9 employer any natural or legal person who has an employment relationship with the worker and has responsibility for the undertaking and/or establishment (Directive 89/391/EEC) BS EN 50496:2008 Licensed CopyChinese Univ
35、ersity of Hong Kong, 11/04/2009 07:41, Uncontrolled Copy, (c) BSI EN 50496:2008 - 6 - 3.10 exposure limit values limits on exposure to electromagnetic fields in 8 which are based directly on established health effects and biological considerations. Compliance with these limits will ensure that worke
36、rs exposed to electromagnetic fields are protected against all known adverse health effects of electromagnetic fields 3.11 local safety Instruction safety instructions relating to a specific broadcast site and containing the information specified in Clause 8: it must include all the necessary safety
37、-related indications and, if applicable, point out the possible risk of exposure to electromagnetic fields where these are at levels above the worker action values; it could include all the necessary safety-related indications and, if applicable, point out the possible risk of exposure to electromag
38、netic fields where these are at levels above the limits for the general public 3.12 transmitter device to generate the radio frequency broadcast signal which is fed into the antenna system 3.13 worker any person employed by an employer, including trainees and apprentices but excluding domestic serva
39、nts (Directive 89/391/EEC) 3.14 work place location where workers have access as part of their duties; particular place of work within the broadcast site as for example the area near a transmitter with an open enclosure, the area inside a transmitting antenna, on a ladder inside a broadcast mast / t
40、ower and platforms under and above the antennas, the area around feed lines, etc. 4 Assessment methods 4.1 Worker exposure assessment The assessment should be done using the steps outlined below: collection of technical data (Clause 5); determination of exposure levels by calculation or measurement
41、(Clause 6). This includes checking of operating procedures in the different exposure work places (Clause 8). The results of the assessment process are: zoning of exposure work places (Clause 7); information and training (Clause 9); assessment report (Clause 10). In the case of simultaneous exposure
42、to multiple sources, the combined exposure shall be considered, referring to Annex A. 4.2 Use of public exposure assessment If an evaluation has already been undertaken in accordance with the provisions of Council Recommendation 1999/519/EC 7, and the restrictions as specified therein are respected,
43、 then the exposure limit values for workers of 8 are also met. BS EN 50496:2008 Licensed CopyChinese University of Hong Kong, 11/04/2009 07:41, Uncontrolled Copy, (c) BSI - 7 - EN 50496:2008 4.3 Assessment after technical modification After technical modification like maintenance or repair of the in
44、stallation or the environment, it is necessary to consider repeating or revising the assessment. This is particularly necessary if an additional transmitter or antenna is added to a site where there are already one or more transmitters. 5 Collection of technical data Information on the following ite
45、ms may be needed: with regard to the surrounding area - information on the nature of the field from any external sources should be obtained from the operators of those sources. Examples of useful information are the frequency, the type of service, and whether the transmissions are intermittent. Howe
46、ver, it should be noted that much of the detailed information may be commercially sensitive. with regard to the site - the area controlled e.g. information on property, fencing, where the controlled area is bounded, - the site map showing all facilities, e.g. buildings, towers, anchor cables, earth
47、net, - the several areas - where a public assessment has been done in compliance with 7 or national regulation, - where workers have access without specific care, - where workers have only access under specific circumstances. with regard to ELF emissions, the location of all 50 Hz site power supplie
48、s or transformers connected to low voltage networks. with regard to the radio-frequency emissions, for each relevant source - the mechanical configuration of the antennas, geometric dimensions, construction drawings, position in the mast, etc., - radiation pattern, polarisation and gain of antennas,
49、 - maximum and nominal power transmitter, - frequency, type of modulation (AM, FM, COFDM, etc.), channel bandwidth, - feeder type and length, attenuation/meter, - additional losses (combiners, patch panels, antenna cables and power dividers). - with regard to scheduling - transmitting time table (especially for short wave), - permitted operating configuration. 6 Determination of exposure levels by calculation or measurement The collection of data permits to take i