1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T K.91 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (07/2017) SERIES K: PROTECTION AGAINST INTERFERENCE Guidance for assessment, evaluation and monitoring of human exposure to radio frequency electromagnetic fields Recomme
2、ndation ITU-T K.91 Rec. ITU-T K.91 (07/2017) i Recommendation ITU-T K.91 Guidance for assessment, evaluation and monitoring of human exposure to radio frequency electromagnetic fields Summary There are many possible methods of exposure assessment and each of them has its own advantages and disadvant
3、ages. Recommendation ITU-T K.91 gives guidance on how to assess and monitor human exposure to radio frequency (RF) electromagnetic fields (EMF) in areas with surrounding radiocommunication installations based on existing exposure and compliance standards in the frequency range of 9 kHz to 300 GHz. T
4、his includes procedures of evaluating exposure and how to show compliance with exposure limits with reference to existing standards. Recommendation ITU-T K.91 is oriented to the examination of the area accessible to people in the real environment of currently operated services with many different so
5、urces of RF EMF, but also gives references to standards and Recommendations related to EMF compliance of products. This Recommendation includes an electronic attachment containing an uncertainty calculator and the Watt Guard modules. History Edition Recommendation Approval Study Group Unique ID* 1.0
6、 ITU-T K.91 2012-05-29 5 11.1002/1000/11634 2.0 ITU-T K.91 2017-07-29 5 11.1002/1000/13276 Keywords Compliance assessment, EMF-guide, monitoring of EMF, RF-EMF, sources of radiation. _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, follow
7、ed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T K.91 (07/2017) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies
8、(ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunicat
9、ion Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of in
10、formation technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating a
11、gency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or s
12、ome other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice or
13、 implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development p
14、rocess. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore stro
15、ngly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2017 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T K.91 (07/2017) iii Table of Contents Page 1 Scope . 1 2 Referen
16、ces . 1 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation . 7 4 Abbreviations and acronyms 7 5 General guidance 8 5.1 General public and occupational exposure . 10 5.2 Existing or planned transmitting station . 10 5.3 Collection of data concerning the sources of
17、radiation 10 5.4 One or more sources of radiation, total exposure . 11 5.5 Field regions . 12 5.6 Basic restrictions and reference levels . 13 5.7 Exposure limits . 13 5.8 Compliance assessment 13 5.9 Uncertainty evaluation 14 5.10 Exposure assessment in areas around hospitals, schools, etc. 15 6 Ge
18、neral characteristics of typical sources of the radiation . 15 6.1 Amplitude modulation transmitting stations 16 6.2 Shortwave transmitting station main beam tilt 16 6.3 Fixed amateur stations 16 6.4 Fixed point-to-point systems 16 6.5 Handsets isotropic sources 17 6.6 VHF and UHF broadcasting trans
19、mitting stations . 21 6.7 2G and 3G mobile base stations . 21 6.8 Smart (adaptive) antennas 21 6.9 Vehicle mounted antennas (such as police car) 21 7 Exposure assessment 21 7.1 Pre-analysis . 21 7.2 Measurements . 22 7.3 Calculations 28 7.4 Comparison between measurement and calculations . 33 7.5 Mo
20、nitoring RF EMF levels 35 8 Conclusions following the exposure assessment 35 9 Final report 35 10 Field levels around typical transmitting antennas 35 11 Conclusions. 36 iv Rec. ITU-T K.91 (07/2017) Page Appendix I Exposure limits 37 I.1 Introduction 37 I.2 Exposure limits . 37 I.3 ICNIRP exposure l
21、imits . 37 I.4 Simultaneous exposure to multiple sources . 39 I.5 IEEE International Committee Electromagnetic Safety (ICES) exposure limits . 40 Appendix II Time averaging . 42 II.1 Analysis of time variations of measured electric fields from WCDMA mobile base stations 42 II.2 Analysis of time vari
22、ations of measured electric fields from GSM mobile base stations 48 II.3 Results and discussion 49 II.4 Discussion about the number of sampling data and averaging time 51 Appendix III Examples of RF EMF levels in areas accessible to the general public . 53 Appendix IV Software Watt Guard 57 Appendix
23、 V Software “Uncertainty calculator“ 58 V.1 Introduction 58 V.2 Brief descriptions of the software . 58 V.3 Examples 60 Appendix VI Examples for evaluating electromagnetic fields in general public environments with broadband radio signals . 64 VI.1 Method for evaluating electromagnetic fields in gen
24、eral public environments with broadband signals 64 VI.2 Effect of RBWs on measured electromagnetic fields from mobile phone base stations 65 Appendix VII Example of block diagram with possible activities during exposure assessment . 68 Bibliography. 70 Electronic attachment containing an uncertainty
25、 calculator, the ITU EMF-guide and the Watt Guard applications described in the Recommendation. Rec. ITU-T K.91 (07/2017) 1 Recommendation ITU-T K.91 Guidance for assessment, evaluation and monitoring of human exposure to radio frequency electromagnetic fields 1 Scope This Recommendation1 gives guid
26、ance on how to assess and monitor human exposure to radio frequency (RF) electromagnetic fields (EMF) in areas with surrounding radiocommunication installations based on existing exposure and compliance standards in the frequency range of 9 kHz to 300 GHz. This Recommendation presents and references
27、 in clear and simple ways, procedures of evaluating exposure and how to show compliance with exposure limits. Existing standards are product or service oriented. This Recommendation is oriented to the examination of the area accessible to people in the real environment of currently operated services
28、 with many different sources of RF EMF, but also gives references to standards and Recommendations related to EMF compliance of products. b-ITU-T K-Suppl.1 provides EMF information and education resources suitable for all communities, stakeholders and governments. It gives answers to questions commo
29、nly posed by the public on EMF and to related concerns. This supplement is also available as a mobile application that is available from http:/emfguide.itu.int/emfguide.html. In b-ITU-T K-Suppl.4 EMF considerations for smart sustainable cities is presented. 2 References The following ITU-T Recommend
30、ations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are theref
31、ore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-
32、alone document, the status of a Recommendation. ITU-T K.52 Recommendation ITU-T K.52 (2004), Guidance on complying with limits for human exposure to electromagnetic fields. ITU-T K.61 Recommendation ITU-T K.61 (2003), Guidance to measurement and numerical prediction of electromagnetic fields for com
33、pliance with human exposure limits for telecommunication installations. ITU-T K.70 Recommendation ITU-T K.70 (2007), Mitigation techniques to limit human exposure to EMFs in the vicinity of radiocommunication stations. ITU-T K.83 Recommendation ITU-T K.83 (2010), Monitoring of electromagnetic field
34、levels. ITU-T K.100 Recommendation ITU-T K.100 (2017), Measurement of radio frequency electromagnetic fields to determine compliance with human exposure limits when a base station is put into service. ITU-T K.113 Recommendation ITU-T K.113 (2015), Generation of radiofrequency electromagnetic field l
35、evel maps. _ 1 This Recommendation contains an electronic attachment containing an uncertainty calculator, ITU EMF-guide and the Watt Guard applications. 2 Rec. ITU-T K.91 (07/2017) ITU-T K.121 Recommendation ITU-T K.121 (2016), Guidance on the environmental management for compliance with radio freq
36、uency EMF limits for radiocommunication base stations. ITU-T K.122 Recommendation ITU-T K.122 (2016), Exposure levels in close proximity of radiocommunication antennas. ITU-R BS.1195 Recommendation ITU-R BS.1195 (2013), Transmitting antenna characteristics at VHF and UHF. ITU-R BS.1698 Recommendatio
37、n ITU-R BS.1698 (2005), Evaluating fields from terrestrial broadcasting transmitting systems operating in any frequency band for assessing exposure to non-ionizing radiation. IEC 62209-1 IEC 62209-1:2016, Measurement procedure for the assessment of specific absorption rate of human exposure to radio
38、 frequency fields from hand-held and body-mounted wireless communication devices - Part 1: Devices used next to the ear (Frequency range of 300 MHz to 6 GHz). https:/webstore.iec.ch/publication/25336 IEC 62209-2 IEC 62209-2:2010, Human exposure to radio frequency fields from hand-held and body-mount
39、ed wireless communication devices Human models, instrumentation, and procedures Part 2: Procedure to determine the specific absorption rate (SAR) for wireless communication devices used in close proximity to the human body (frequency range of 30 MHz to 6 GHz). https:/webstore.iec.ch/publication/6590
40、 IEC 62232 IEC 62232:2017, Determination of RF field strength, power density and SAR in the vicinity of radiocommunication base stations for the purpose of evaluating human exposure. https:/webstore.iec.ch/publication/28673 ISO/IEC Guide 98-3 ISO/IEC Guide 98-3:2008, Uncertainty of measurement Part
41、3: Guide to the expression of uncertainty in measurement (GUM:1995). http:/www.iso.org/iso/catalogue_detail.htm?csnumber=50461 ISO/IEC 17025 ISO/IEC 17025:2005, General requirements for the competence of testing and calibration laboratories. http:/www.iso.org/iso/catalogue_detail.htm?csnumber=39883
42、3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 antenna ITU-T K.70: Device that serves as a transducer between a guided wave (e.g., coaxial cable) and a free space wave, or vice versa. It can be used to emit or receive a radio signal. I
43、n this Recommendation the term antenna is used only for emitting antenna(s). 3.1.2 antenna gain ITU-T K.70: The antenna gain G (, ) is the ratio of power radiated per unit solid angle multiplied by 4 to the total input power. The gain is frequently expressed in decibels with respect to an isotropic
44、antenna (dBi). The formula defining the gain is: where: , : the angles in a polar coordinate system; : the antenna efficiency due to dissipative losses; ddPPG rini 4),(Rec. ITU-T K.91 (07/2017) 3 Pr: the radiated power in the (, ) direction; Pin: the total input power; d: an elementary solid angle i
45、n the direction of observation. NOTE In manufacturers catalogues the antenna gain is understood as a maximum value of the antenna gain. Gain does not include losses arising from impedance and polarization mismatches. If an antenna is without dissipative loss, then its gain is equal to its directivit
46、y D (, ). 3.1.3 average (temporal) power (Pavg) ITU-T K.52: The time-averaged rate of energy transfer defined by: where: P(t) is the instantaneous power; t1 and t2 are the start and stop time of the exposure. 3.1.4 averaging time (Tavg) ITU-T K.52: The averaging time is the appropriate time period o
47、ver which exposure is averaged for purposes of determining compliance with the limits. 3.1.5 basic restrictions ITU-T K.70: Restrictions on exposure to time-varying electric, magnetic and electromagnetic fields that are based directly on established health effects. Depending upon the frequency of th
48、e field, the physical quantities used to specify these restrictions are: current density (J), specific absorption rate (SAR) and power density (S). 3.1.6 body mounted device body worn device IEC 62209-2: A portable device containing a wireless transmitter or transceiver which may be located close to
49、 a persons torso except the head during its intended use or operation of its radio functions (e.g., on a belt clip, holster, pouch, or on a lanyard when worn as necklace). 3.1.7 compliance distance ITU-T K.70: Minimum distance from the antenna to the point of investigation where the field level is deemed to be compliant with the limits. 3.1.8 contact current ITU-T K.52: Contact current is the current flowing in
