Recommendation ITU-T K.91 (01/2024) Guidance for assessment, evaluation and monitoring of human exposure to radio frequency electromagnetic fields
Summary
History
FOREWORD
Table of Contents
1 Scope
2 References
3 Definitions
     3.1 Terms defined elsewhere
     3.2 Terms defined in this Recommendation
4 Abbreviations and acronyms
5 General guidance
     5.1 General public and occupational exposure
     5.2 Existing or planned transmitting station
     5.3 Collection of data concerning sources of radiation
          5.3.1 Data required for measurement
          5.3.2 Data required for calculation
     5.4 One or more sources of radiation, total exposure
     5.5 Field regions
     5.6 Basic restrictions and reference levels
     5.7 Exposure limits
     5.8 Compliance assessment
     5.9 Uncertainty evaluation
     5.10 Exposure assessment in areas around hospitals, schools, etc.
6 General characteristics of typical sources of the radiation
     6.1 Amplitude modulation transmitting stations
     6.2 Shortwave transmitting station – main beam tilt
     6.3 Fixed amateur stations
     6.4 Fixed point-to-point systems
     6.5 Personal wireless communication devices
          6.5.1 SAR compliance procedures for personal wireless communication devices used against the head
          6.5.2 SAR compliance of personal wireless communication devices used in close proximity to the human body
          6.5.3 Compliance of the wireless communication device with hands-free kit
          6.5.4 Power density compliance of personal wireless communication devices
     6.6 Wireless power transfer systems
     6.7 VHF and UHF broadcasting transmitting stations
     6.8 2G, 3G and 4G mobile base stations
     6.9 Smart (adaptive) antennas
     6.10 Vehicle mounted antennas (such as police car)
7 Exposure assessment for fixed stations
     7.1 Pre-analysis
     7.2 Measurements
          7.2.1 Selection of the points of investigation
          7.2.2 Spatial averaging
          7.2.3 Time averaging for measurement procedure
          7.2.4 Broadband measurement
          7.2.5 Frequency-selective measurement
          7.2.6 Near-field measurement
          7.2.7 Post-processing
          7.2.8 SAR measurement
     7.3 Calculations
          7.3.1 Methods of calculation in different field regions
               7.3.1.1 Point-source model
               7.3.1.2 Synthetic model
               7.3.1.3 Full-wave methods
               7.3.1.4 SAR calculations
               7.3.1.5 Influence of the reflections
          7.3.2 Modelling of the transmitting antennas
          7.3.3 Radiated power ERP/EIRP evaluation
     7.4 Comparison between measurement and calculation
     7.5 Monitoring RF EMF levels
8 Conclusions following the exposure assessment
9 Final report
10 Field levels around typical transmitting antennas
11 Conclusions
Appendix I  Exposure limits
     I.1 Introduction
     I.2 ICNIRP-2010 and ICNIRP-2020 guidelines in force
          I.2.1 Elaborating the tables and figures of [b-ICNIRP 2020]
     I.3 IEEE C95.1-2019
          I.3.1 Reference levels: safety factors applying 100 kHz – 6 GHz; thermal effects
          I.3.2 Dosimetric reference limits and exposure reference level
     I.4 Simultaneous exposure to multiple sources
          I.4.1 Basic restrictions
Appendix II  Time averaging
     II.1 Analysis of time variations of measured electric fields from WCDMA mobile base stations
     II.2 Analysis of time variations of measured electric fields from GSM mobile base stations
     II.3 Results and discussion
          II.3.1 RBW
          II.3.2 Measurement time
     II.4 Discussion about the number of sampling data and averaging time
Appendix III  Examples of RF EMF levels in areas accessible to the general public
Appendix IV  Watt guard software
Appendix V  Uncertainty calculator software
     V.1 Introduction
     V.2 Brief description of the software
     V.3 Examples
Appendix VI  Examples for evaluating electromagnetic fields in general public environments with broadband radio signals
     VI.1 Method for evaluating electromagnetic fields in general public environments with broadband signals
     VI.2 Effect of RBWs on measured electromagnetic fields from mobile phone base stations
Appendix VII  Example of block diagram with possible activities during exposure assessment
Appendix VIII  "EMF exposure" mobile app
     VIII.1 Introduction
     VIII.2 Brief description of the main features of "EMF exposure"
     VIII.3 Brief description of the calculations done by "EMF exposure"
Bibliography