1、BRITISH STANDARDBS EN 50444:2008Basic standard for the evaluation of human exposure to electromagnetic fields from equipment for arc welding and allied processesICS 13.280; 25.160.10g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g
2、36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 50444:2008This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2008 BSI 2008ISBN 978 0 580 53819 3National forewordThis British Standard is the UK imp
3、lementation of EN 50444:2008. The UK participation in its preparation was entrusted to Technical Committee WEE/6, Electric arc welding equipment.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the nece
4、ssary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments/corrigenda issued since publicationDate CommentsEUROPEAN STANDARD EN 50444 NORME EUROPENNE EUROPISCHE NORM February 2008 CENEL
5、EC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2008 CENELEC - All rights of exploitation in any form and by any means reserved world
6、wide for CENELEC members. Ref. No. EN 50444:2008 E ICS 13.280; 25.160.10 English version Basic standard for the evaluation of human exposure to electromagnetic fields from equipment for arc welding and allied processes Norme de base pour lvaluation de lexposition des personnes aux champs lectromagnt
7、iques dun quipement pour le soudage larc et les techniques connexes Grundnorm zur Ermittlung der Exposition von Personen gegenber elektromagnetischen Feldern von Einrichtungen zum Lichtbogenschweien und artverwandten Prozessen This European Standard was approved by CENELEC on 2008-02-01. CENELEC mem
8、bers 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 applicat
9、ion 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
10、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, Italy, Latvia, Lithuania, Luxembourg, Malta, the Nether
11、lands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN 50444:2008 2 Foreword This European Standard was prepared by the Technical Committee CENELEC TC 26A, Electric arc welding equipment. The text of the draft was submitted to the formal v
12、ote and was approved by CENELEC as EN 50444 on 2008-02-01. 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) 2009-02-01 latest date by which the national standards conflicting w
13、ith the EN have to be withdrawn (dow) 2011-02-01 This European Standard is to be read in conjunction with EN 50445. This European Standard has been prepared under mandates M/305 and M/351 given to CENELEC by the European Commission and the European Free Trade Association. _ BS EN 50444:2008 3 EN 504
14、44:2008 Contents 1 Scope .6 2 Normative references .6 3 Terms and definitions 6 3.1 General.6 3.2 Specific for arc welding and similar applications8 4 Physical quantities, units and constants .9 4.1 Quantities and units9 4.2 Constants9 5 Assessment procedures 9 5.1 Arc welding equipment components t
15、o be tested 9 5.2 Assessment conditions.9 5.3 Averaging9 5.4 Pulsed or non-sinusoidal welding current.9 5.4.1 General 9 5.4.2 Summation for basic restriction assessment.10 5.4.2.1 Summation of current density components without phase information .10 5.4.2.2 Summation of currents density components i
16、ncluding phase information10 5.4.2.3 Summation of specific absorption rate (SAR) components .11 5.4.3 Summation for reference level assessment 11 5.4.3.1 Summation for stimulation effects without phase information11 5.4.3.2 Effective reference level method12 5.4.3.3 Summation for stimulation effects
17、 including phase information.13 5.4.3.4 Summation for thermal effects .13 5.4.4 Equivalent frequency of induced current density waveforms 13 5.5 Conductivity of living tissue 14 5.6 Frequency range limitations .14 5.7 Application of assessment procedures.15 5.8 Measurements16 5.8.1 Measuring equipme
18、nt 16 5.8.2 Static field measurements .17 5.8.3 Time domain field measurements .17 5.8.4 Broadband field measurements.17 5.8.5 Frequency selective field measurements 17 5.8.6 Time domain weighted field measurements18 5.9 Analytical calculations 18 5.9.1 General information .18 5.9.2 Derivation of ma
19、gnetic field based on welding current18 5.9.3 Derivation of induced current density based on magnetic field.19 BS EN 50444:2008EN 50444:2008 4 5.10 Numerical calculations20 5.10.1 General information .20 5.10.2 Derivation of magnetic field .20 5.10.3 Derivation of current density using conductive di
20、sc models20 5.10.4 Simulations based on anatomical body models 21 5.10.4.1 General information21 5.10.4.2 Anatomical body models 21 5.10.4.3 Calculation methods.22 5.10.4.4 Position of the body model in relation to the welding cables .22 6 Uncertainty of assessment22 6.1 Including uncertainty.22 6.1
21、.1 General information .22 6.1.2 Shared uncertainty budget 22 6.1.3 Using uncertainty in comparison against limit values23 6.2 Evaluation of uncertainties .23 6.2.1 Introduction 23 6.2.2 Individual uncertainties 23 6.2.3 Combined uncertainties.23 6.3 Reasonable overall uncertainties .23 6.4 Examples
22、 of typical uncertainties .24 7 Assessment report .25 7.1 General principles.25 7.2 Items to be recorded in the assessment report25 Annex A (normative) Assessment parameters26 Annex B (informative) Examples for exposure assessment 30 Annex C (informative) Numerical simulation using anatomical body m
23、odels .39 Annex D (informative) Geometry factor and field gradients.43 Annex E (informative) Welding current ripple assessment44 Annex F (informative) Summation using first order filter weighting functions46 Annex G (informative) Example for an uncertainty budget 50 Bibliography51 BS EN 50444:2008 5
24、 EN 50444:2008 Figures Figure 1 Average electrical conductivities for homogeneous body modelling from 10 Hz to 10 MHz .14 Figure A.1 Probe position for measurement on welding cables27 Figure A.2 Topology of welding cable for numerical simulations 28 Figure B.1 Probe position during measurement31 Fig
25、ure B.2 Planar current density distribution in the disk32 Figure B.3 Welding current waveform and calculation parameters 33 Figure B.4 Induced current density derived from welding current.33 Figure B.5 Spectral components of welding current pulse34 Figure B.6 Summation of induced current density com
26、ponents with phase information 35 Figure B.7 Flux density waveform and r.m.s. values of the spectral components35 Figure B.8 Flux density waveform and r.m.s. values of the spectral components36 Figure B.9 Summation of flux density components with phase information37 Figure B.10 Flux density waveform
27、 and r.m.s. values of the spectral components37 Figure D.1 Planar field distribution for different cable arrangements at I2 = 200 A .43 Figure E.1 Spectral analysis of triangular function44 Figure F.1 Magnetic flux density reference levels, filter and tabulated values47 Figure F.2 Weighting function
28、 phase angles for B and H, filter and tabulated values 47 Figure F.3 Induced current density basic restrictions, filter and tabulated values 48 Figure F.4 Weighting function phase angles for J, filter and tabulated values49 Figure F.5 Comparison of results for example B.7 (first order filter left, t
29、abulated values right).49 Tables Table 1 Permissible assessment procedures for arc welding equipment.15 Table 2 Permissible assessment procedures for welding cables .16 Table 3 Reasonable expanded assessment uncertainties24 Table A.1 Typical parameters for tests with pulsed welding current.26 Table
30、B.1 Induced current density components and phase angles 34 Table B.2 Flux density components 35 Table B.3 Flux density components and phase angles.36 Table B.4 Flux density components and fractional contributions38 Table C.1 Electrical conductivity of tissue types .41 Table E.1 J simulation results
31、for relevant spectral components (r.m.s. values)45 Table E.2 B calculation results for relevant spectral components (r.m.s. values).45 Table G.1 Example uncertainty budget for broadband field measurement.50 BS EN 50444:2008EN 50444:2008 6 1 Scope This European Standard applies to equipment for arc w
32、elding and allied processes designed for use in industrial or domestic environments, including welding power sources, wire feeders and ancillary equipment, e.g. torches, liquid cooling systems and arc striking and stabilising devices. NOTE Allied processes are for example electric arc cutting and ar
33、c spraying. This standard specifies procedures for assessment of electromagnetic fields produced by arc welding equipment and defines standardized operating conditions and test set-ups. This standard may be used as a basis to demonstrate compliance to national and international guidelines or require
34、ments with regard to human exposure to EMF from arc welding equipment 1 2. Other standards may apply to products covered by this standard. In particular this standard can not be used to demonstrate electromagnetic compatibility with other equipment; nor does it specify any product safety requirement
35、s other than those specifically related to human exposure to 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 t
36、he referenced document (including any amendments) applies. EN 50392 Generic standard to demonstrate the compliance of electronic and electrical apparatus with the basic restrictions related to human exposure to electromagnetic fields (0 Hz 300 GHz) EN 50445 Product family standard to demonstrate com
37、pliance of equipment for resistance welding, arc welding and allied processes with the basic restrictions related to human exposure to electromagnetic fields (0 Hz 300 GHz) EN 60974-1 Arc welding equipment Part 1: Welding power sources (IEC 60974-1) 3 Terms and definitions For the purposes of this d
38、ocument, the following terms and definitions apply. 3.1 General 3.1.1 basic restrictions restrictions on exposure to electric, magnetic and electromagnetic fields that are based directly on established health effects and biological considerations 3.1.2 conductivity () ratio of the conduction current
39、 density in a medium to the electric field strength 3.1.3 contact current current flowing into the body by touching a conductive object in an electromagnetic field BS EN 50444:2008 7 EN 50444:2008 3.1.4 effective reference level (BL,eff) level, provided for practical exposure assessment purposes usi
40、ng a broadband measurement, derived from frequency dependent reference levels considering the spectral content of the field 3.1.5 EMF electric, magnetic or electromagnetic field 3.1.6 exposure situation that occurs when a person is subjected to electric, magnetic or electromagnetic fields or to cont
41、act current other than those originating from physiological processes in the body and other natural phenomena 3.1.7 exposure level value of the quantity evaluated when a person is exposed to electromagnetic fields or contact currents 3.1.8 induced current density (J) electromagnetic field induced cu
42、rrent per unit area inside the body 3.1.9 magnetic flux density (B) magnitude of a field vector that is equal to the magnetic field H multiplied by the permeability of the medium B = H (1) 3.1.10 magnetic field strength (H) magnitude of a field vector in a point that results in a force Fron a charge
43、 q moving with velocity vrFr= q ( vrx Hr) (2) or magnetic flux density divided by permeability of the medium 3.1.11 permeability () property of a material which defines the relationship between magnetic flux density B and magnetic field strength H NOTE It is commonly used as the combination of the p
44、ermeability of free space 0and the relative permeability R for specific dielectric materials = R0(3) where is the permeability of the medium expressed in Henry per metre (H m-1). 3.1.12 point of investigation (POI) location in space at which the value of E-field, H-field or power density is evaluate
45、d NOTE This location is defined in Cartesian, cylindrical or spherical co-ordinates relative to the reference point on the EUT. BS EN 50444:2008EN 50444:2008 8 3.1.13 root-mean-square (r.m.s.) effective value or the value associated with joule heating, of a periodic electromagnetic wave NOTE The r.m
46、.s. value is obtained by taking the square root of the mean of the squared value of a function. Expression in time domain =TdttXTX02r.m.s.)(1(4) where X(t) is the signal at time t; T is the signal period or multiples of it. Expression in frequency domain =nnXX2r.m.s.(5) where Xn is the magnitude of
47、spectral component at nth frequency, expressed as r.m.s. value. 3.1.14 reference levels directly measurable quantities, derived from basic restrictions, provided for practical exposure assessment purposes NOTE Respect of the reference levels will ensure respect of the relevant basic restriction. If
48、the reference levels are exceeded, it does not necessarily follow that the basic restriction will be exceeded. 3.2 Specific for arc welding and similar applications 3.2.1 arc welding power source equipment for supplying current and voltage and having the required characteristics suitable for arc wel
49、ding and allied processes NOTE 1 An arc welding power source may also supply services to other equipment and auxiliaries e.g. auxiliary power, cooling liquid, consumable arc welding electrode and gas to shield the arc and the welding area. NOTE 2 In the following text, the term “welding power source” is used. 3.2.2 industrial and professional use use intended only for experts or instructed persons 3.2.3 expert (competent person, skilled person)
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