IEC TR 62669:2011

Case studies supporting IEC 62232 - Determination of RF field strength and SAR in the vicinity of radiocommunication base stations for the purpose of evaluating human exposure

IEC/TR 62699:2011(E) is a technical report. It contains a series of case studies for the evaluation of electromagnetic (EM) sources in the frequency range 100 kHz - 300 GHz to support the methods detailed in the international standard IEC 62232, Determination of RF field strength and SAR in the vicinity of radiocommunication base stations for the purpose of evaluating human exposure. Using the methods detailed in the standard, each case study has been chosen to illustrate a typical radio base station (RBS) evaluation scenario. Some of the case studies demonstrate more than one evaluation method. However, in most situations only one method would be required to complete an evaluation. The case studies documented in this report are provided for guidance only and are not a substitute for a thorough understanding of the requirements of IEC 62232. This publication contains attached files in the form of a CD-ROM for the paper version and embedded files for the electronic version. These files are intended to be used as a complement and do not form an integral part of the standard.

General Information

• Status: Published
• Publication Date: 26-May-2011
• ICS: 13.280 - Radiation protection
• ICS: 17.240 - Radiation measurements
• Technical Committee: TC 106 - Methods for the assessment of electric, magnetic and electromagnetic fields associated with human exposure
• Current Stage: DELPUB - Deleted Publication
• Start Date: 30-Apr-2018
• Completion Date: 05-Apr-2019

Relations

• Revised: IEC TR 62669:2019 - Case studies supporting IEC 62232 - Determination of RF field strength, power density and SAR in the vicinity of radiocommunication base stations for the purpose of evaluating human exposure
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC/TR 62669


®


Edition 1.0 2011-05



TECHNICAL



REPORT





colour
inside


Case studies supporting IEC 62232 – Determination of RF field strength and SAR
in the vicinity of radiocommunication base stations for the purpose of evaluating
human exposure


IEC/TR 62669:2011(E)

---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED


Copyright © 2011 IEC, Geneva, Switzerland

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by

any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either IEC or

IEC's member National Committee in the country of the requester.
If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,
please contact the address below or your local IEC member National Committee for further information.




Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de la CEI ou du Comité national de la CEI du pays du demandeur.

Si vous avez des questions sur le copyright de la CEI ou si vous désirez obtenir des droits supplémentaires sur cette

publication, utilisez les coordonnées ci-après ou contactez le Comité national de la CEI de votre pays de résidence.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: [e-mail]
Web: www.iec.ch

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.
 Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
 IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
 Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
 Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: [e-mail]
Tel.: [phone]
Fax: [phone]

---------------------- Page: 2 ----------------------
IEC/TR 62669


®

Edition 1.0 2011-05



TECHNICAL



REPORT



colour
inside


Case studies supporting IEC 62232 – Determination of RF field strength and SAR
in the vicinity of radiocommunication base stations for the purpose of evaluating
human exposure



INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XH
ICS 13.280; 17.240 ISBN 978-2-88912-528-9
® Registered trademark of the International Electrotechnical Commission

---------------------- Page: 3 ----------------------
– 2 – TR 62669 © IEC:2011(E)



CONTENTS

FOREWORD . 3


INTRODUCTION . 5

1 Scope . 6

2 Normative references . 6


3 Terms, definitions, symbols and abbreviated terms . 6

4 Overview of case studies . 6

4.1 Case study synopsis . 6

4.2 Micro cell case study . 7
4.3 Roof-top case study with nearby apartment buildings . 8
4.4 Roof-top / tower case study in residential area . 9
4.5 Roof-top case study with direct access to antennas . 10
4.6 Roof-top case study with large antennas and no direct access . 11
4.7 Circular cylindrical compliance boundary determination case study with large
antennas and no direct access . 11
4.8 Tower case study in parkland . 12
4.9 Multiple towers case study at sports venue . 13
4.10 In-building base station case study . 14
Annex A (informative) Micro cell case study . 16
Annex B (informative) Roof-top case study with nearby apartments . 41
Annex C (informative) Roof-top / tower case study in residential area . 68
Annex D (informative) Roof-top case study with direct access to antennas . 98
Annex E (informative) Roof-top case study with no direct access to antennas . 126
Annex F (informative) Circular cylindrical compliance boundary determination case
study . 143
Annex G (informative) Tower case study in parkland . 155
Annex H (informative) Tower case study at sports venue . 170
Annex I (informative) In-building base station case study . 191
Annex J (informative) Evaluation template and sample uncertainty table . 212

Figure 1 – Micro cell case study . 7
Figure 2 – Roof-top case study with nearby apartment buildings . 8

Figure 3 – Roof-top / tower case study in residential area . 9
Figure 4 – Roof-top case study with direct access to antennas . 10
Figure 5 – Roof-top case study with large antennas and no direct access . 11
Figure 6 – Cylindrical compliance boundary determination for dual band antenna on
building . 12
Figure 7 – Tower case study in parkland . 13
Figure 8 – Multiple towers case study at sports venue . 14
Figure 9 – Office building IBC case study . 15

---------------------- Page: 4 ----------------------
TR 62669 © IEC:2011(E) – 3 –


INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________



CASE STUDIES SUPPORTING IEC 62232 –

DETERMINATION OF RF FIELD STRENGTH AND SAR IN THE VICINITY

OF RADIOCOMMUNICATION BASE STATIONS FOR THE PURPOSE

OF EVALUATING HUMAN EXPOSURE





FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

The main task of IEC technical committees is to prepare International Standards. However, a
technical committee may propose the publication of a technical report when it has collected
data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC 62669, which is a technical report, has been prepared by IEC technical committee 106:
Methods for the assessment of electric, magnetic and electromagnetic fields associated with
human exposure.
This publication contains attached files in the form of a CD-ROM for the paper version and
embedded files for the electronic version. These files are intended to be used as a
complement and do not form an integral part of the technical report.

---------------------- Page: 5 ----------------------
– 4 – TR 62669 © IEC:2011(E)


The text of this technical report is based on the following documents:

Enquiry draft Report on voting


106/199/DTR 106/208/RVC



Full information on the voting for the approval of this technical report can be found in the

report on voting indicated in the above table.


This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.


The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.

---------------------- Page: 6 ----------------------
TR 62669 © IEC:2011(E) – 5 –


INTRODUCTION


This technical report contains a series of case studies for the evaluation of electromagnetic

(EM) sources in the frequency range 100 kHz - 300 GHz to support the methods detailed in

the international standard IEC 62232, Determination of RF field strength and SAR in the

vicinity of radiocommunication base stations for the purpose of evaluating human exposure.

Using the methods detailed in the standard, each case study has been chosen to illustrate a

typical radio base station (RBS) evaluation scenario.

---------------------- Page: 7 ----------------------
– 6 – TR 62669 © IEC:2011(E)


CASE STUDIES SUPPORTING IEC 62232 –

DETERMINATION OF RF FIELD STRENGTH AND SAR IN THE VICINITY

OF RADIOCOMMUNICATION BASE STATIONS FOR THE PURPOSE

OF EVALUATING HUMAN EXPOSURE








1 Scope


This technical report presents a series of case studies in which electromagnetic (EM) fields
are evaluated in accordance with IEC 62232. It also provides a reporting template cross
referenced to IEC 62232.
Each case study has been chosen to illustrate a typical radio base station (RBS) evaluation
scenario and employs the methods detailed in IEC 62232. Some of the case studies
demonstrate more than one evaluation method. However, in most situations only one method
would be required to complete an evaluation.
The case studies documented in this report are provided for guidance only and are not a
substitute for a thorough understanding of the requirements of IEC 62232.
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 the referenced document (including any amendments) applies.
IEC 62232: Determination of RF field strength and SAR in the vicinity of radiocommunication
base stations for the purpose of evaluating human exposure
3 Terms, definitions, symbols and abbreviated terms
For the purposes of this document, the terms, definitions, symbols and abbreviated terms
given in IEC 62232 apply.
4 Overview of case studies

4.1 Case study synopsis
This clause provides a summary of worked evaluation examples at a number of RBS sites
using a range of methods described in IEC 62232. The example sites include roof-tops,
towers, poles, micro cells and in-building cells.
The case studies have been chosen to illustrate typical RBS sites and common evaluations.
Some of the case studies demonstrate multiple evaluation methods. However in most
situations only one method would be required to complete an evaluation.
NOTE The coloured left-side page margins in the annexes indicates the pages are unchanged versions of sample
RF exposure evaluation reports contributed by TC 106 project team members.

---------------------- Page: 8 ----------------------
TR 62669 © IEC:2011(E) – 7 –


4.2 Micro cell case study

The purpose of this case study was to evaluate the RF exposure compliance boundaries from

a particular micro cell installation on a building wall to determine whether they would extend

to a nearby awning. Compliance boundaries were determined based on a) basic restrictions

and b) reference levels to determine the minimum distance from the antenna to the

compliance boundary.


The maximum values were compared against international safety guidelines known as ICNIRP

(International Commission on Non-Ionizing Radiation Protection) guidelines. The assessment

establishes compliance against the basic restrictions known as specific absorption rate (SAR)

and the spatially averaged field strength reference levels. SAR testing was performed in a
laboratory and frequency selective field measurements were performed on site.
The equipment under test (EUT) was categorised as a simple RBS due to the single
technology and single antenna of the micro cell. Nearby base stations, known as secondary
sources, had negligible impact on both SAR and field strength evaluations.
The measured SAR and field strength levels were extrapolated to assess the maximum power
configuration for the site.
The “best estimate” uncertainty model was applied and the measured levels are reported
including the extrapolation for maximum base station power configuration. The uncertainty is
stated for all assessment methods used.
The compliance boundary distance for general public exposure using the on-site field strength
measurement was 0,8 m and 0,08 m using the SAR evaluation.
Both the SAR evaluation and the on-site field strength measurements confirm that the general
public exposure compliance boundary from the micro cell antenna does not extend onto the
building awning, therefore access is permitted on the awning.
This case study illustrates:
• the benefit of conducting a SAR evaluation on the small micro cell antenna to minimise its
exclusion zone;
• evaluation of RF fields from cellular base station antennas located in close proximity to a
roof-top awning accessible to maintenance staff.
Figure 1 shows the surveyor and the micro cell antenna installed on the building wall in
Stockholm. The case study is available in full in Annex A.


Figure 1 – Micro cell case study

---------------------- Page: 9 ----------------------
– 8 – TR 62669 © IEC:2011(E)


4.3 Roof-top case study with nearby apartment buildings


The purpose of this case study was to verify the RF exposure levels in the accessible areas of

an office building roof-top with a cellular base station are below the uncontrolled environment

exposure limits in Health Canada’s Safety Code 6 Guidelines. The building roof-top has

cellular base station panel antennas from two separate operators, and is located near an
apartment building, residential and commercial areas.


The equipment under test (EUT) was categorised as a Complex RBS as there are multiple

antenna systems at the site under evaluation.


This evaluation was performed by Industry Canada as part of their regulatory auditing

program of radio communication and broadcasting sites. The evaluation consisted of
computational modelling to determine the RF exposure compliance boundaries around the
antennas, and on-site frequency selective field strength measurements to determine the RF
exposure levels in accessible areas.
The RF exposure compliance boundary (uncontrolled environment) was assessed to be 6 m
directly in front of the panel antennas.
The maximum exposure level on the building roof-top was assessed to be 5,1% of Safety
Code 6 limits for the uncontrolled environment. This was on the southwest side of the roof-top
underneath the cellular base station panel antennas. The maximum exposure level on the
building adjacent to the base station was assessed to be 0,51% of Safety Code 6 limits for the
uncontrolled environment. This was on the roof-top car park.
Results are presented for this case study using both the best estimate and upper 95 % CI
assessment schemes. The exposure levels reported using the upper 95 % CI assessment
scheme i.e. including the measurement equipment expanded uncertainty in the reported level.
The exposure levels reported using the best estimate assessment scheme state the actual
level evaluated and the uncertainty factor for the measurement equipment.
This case study illustrates:
• evaluation of RF field strength from cellular base station antennas which are mounted on
the roof-top of an office building and are accessible to maintenance workers;
• evaluation of RF field strength from cellular base stations which are located near an
apartment building, residential and commercial areas;
• full compliance assessment of the site is achieved even if accessibility to certain locations
was not possible;
• the results of two spatial averaging schemes are compared.
Figure 2 (left) shows the roof-top installation from a position across the street; while Figure 2

(right) shows the surveyor and base station antennas in-situ. The building is located in
Montreal. The case study is available in full in Annex B.


Figure 2 – Roof-top case study with nearby apartment buildings

---------------------- Page: 10 ----------------------
TR 62669 © IEC:2011(E) – 9 –


4.4 Roof-top / tower case study in residential area


The purpose of this case study was to verify RF exposure compliance in a residential and

commercial area surrounding a building with a roof-top cellular base station and satellite

broadcast radio repeater. The antenna structure is mounted on the second level roof-top of an

office building. The equipment under test (EUT) was categorised as a Complex RBS as there
are multiple antenna systems at the site under evaluation.



This assessment compared the results of the evaluations against limits set forth in Health
Canada’s Safety Code 6 guidelines. This compliance assessment was performed by Industry

Canada as part of their regulatory auditing program of radio communication and broadcasting

sites. The evaluations consisted of computational modelling to determine the RF exposure

compliance boundaries around the antennas, and frequency selective field strength
measurements to determine the RF exposure levels in the surrounding residential and
commercial areas. The accessible areas of the roof-top were also measured.
The RF exposure compliance boundary (uncontrolled environment) was assessed to be 4 m
directly in front of the cellular panel antennas, and 2 m directly in front of the satellite
broadcast repeater antenna.
The maximum exposure level on the building roof-top was assessed to be 23,92 % of Safety
Code 6 limits for the uncontrolled environment which was located a few meters in front of the
satellite broadcasting repeater. This location is not accessible to the general public. The
maximum exposure level in the residential and commercial areas around the building was
assessed to be 0,044 % of Safety Code 6 limits for the uncontrolled environment.
Results are presented for this case study using both the best estimate and upper 95 % CI
assessment schemes. The exposure levels reported using the upper 95 % CI assessment
scheme include the measurement equipment expanded uncertainty in the reported level. The
exposure levels reported using the best estimate assessment scheme state the actual level
assessed and the uncertainty factor for the measurement equipment.
This case study illustrates:
• evaluation of RF field strength from cellular base station antennas and satellite broadcast
radio repeater which are mounted on a multi-storey building, which houses a centre for
continuing education;
• evaluation of RF field strength from cellular base station signals in a residential area;
• the comparison of the results of two (2) spatial averaging schemes.
Figure 3 shows the building in Montreal, which is subject of the evaluation; Figure 3 (left) is
wide shot of the environment surrounding the building, while a close-up of the structure and

antennas is shown in Figure 3 (right). The case study is available in full in Annex C.


Figure 3 – Roof-top / tower case study in residential area

---------------------- Page: 11 ----------------------
– 10 – TR 62669 © IEC:2011(E)


4.5 Roof-top case study with direct access to antennas


The purpose of this case study was to determine the RF exposure compliance and control

boundaries around an operational roof-top macro base station. It demonstrates the validity of

both measurement and computation evaluation methods for this base station situation.

The compliance boundary assessment determined the area around the base station antennas
where the exposure limits are not exceeded, and the control boundary assessment confirmed

the location of the physical access controls such as barriers and warning signs. The

evaluation included on-site spatially averaged field strength measurement at the control

boundary and a desktop computation to determine the compliance boundary. The maximum

values were compared against the ICNIRP international safety guidelines.

An initial visual inspection at the site showed the potential for a significant RF field
contribution from other RF sources. A wide frequency sweep established that the ambient
contribution would not be significant and hence only the RF fields from the RBS under
evaluation needed to be considered. Prior to the on-site field strength measurements, an
initial estimate of the control boundary distance was calculated to be 13,2 m from the
antennas for the general public limit and 3,2 m for the occupational exposure limit.
Spatially averaged field strength measurements were then performed on the roof-top at the
selected control boundary distances of 13,2 m and 3,2 m from the antennas. The
measurements demonstrated the actual field strength levels were well below the occupational
and general public limits allowing for the maximum operating power. This verifies that
conservative control boundaries have been selected.
A separate desktop evaluation using a commercial computation tool with ray tracing
determined that the distance from the antenna to general public compliance boundary was
less than 10 m, and less than 1 m to the occupational compliance boundary, along the
maximum exposure radial under maximum operating power.
Full uncertainty analyses were performed for both evaluation methods indicating high
confidence that actual exposure would be less than the ICNIRP limits at the specified control
boundary distances. The best estimate assessment scheme was used for both the desktop
evaluation and field strength measurement.
This case study illustrates:
• evaluation of RF field strength from cellular base station antennas with direct access to
the antennas;
• comparison of computational evaluation and on-site measurement;
• identification of compliance boundaries on the roof-top.

Figure 4 shows the evaluation site, in Cape Town. It is an example of a roof-top site with
direct access to the antennas, which in this example are flush mounted on building’s exterior.
The case study is available in full in Annex D.

Figure 4 – Roof-top case study with direct access to antennas

---------------------- Page: 12 ----------------------
TR 62669 © IEC:2011(E) – 11 –


4.6 Roof-top case study with large antennas and no direct access


The purpose of this case study is to evaluate the RF exposure levels in accessible areas on a

building roof-top in Tokyo.


The equipment under test (EUT) was categorised as a Complex RBS due to the multiple

frequency bands and technologies supported.


The evaluation involved frequency selective measurements of the radio base station control

channels and extrapolation for maximum operating power. The maximum values were

compared against the ICNIRP guideline.

The assessment showed that the total exposure level from the mobile base station antennas
in accessible areas of the building roof-top was lower than the specified limits at maximum
traffic, as well as at the available maximum transmitting power.
This evaluation was performed using a target uncertainty assessment scheme. If the target
uncertainty is met, then the measured value is compared directly with the limit. If the target
uncertainty is not met, then the comparator is the measured value increased to the upper
95 % confidence level. In this case study the target uncertainty was met.
This case study illustrates:
• RF exposure levels in accessible areas of a building roof-top from a complex base station;
• an assessment using a target uncertainty scheme;
• comparison of computational evaluation and on-site measurements;
• frequency selective spatial average measurements;
• evaluation of nearby radio and broadcast signal levels.
Figure 5 shows the roof-top in Isehara City, Japan used for this case study.
The case study is available in full in Annex E.


Figure 5 – Roof-top case study with large antennas and no direct access
4.7 Circular cylindrical compliance boundary determination case study with large
antennas and no direct access
The purpose of this survey was to determine a radio frequency (RF) exposure compliance
boundary (occupational and general public) for a
...