IEC 60721-2-4:2018
(Main)Classification of environmental conditions - Part 2-4: Environmental conditions appearing in nature - Solar radiation and temperature
Classification of environmental conditions - Part 2-4: Environmental conditions appearing in nature - Solar radiation and temperature
IEC 60721-2-4:2018 presents a broad division into types of solar radiation areas. It is intended to be used as part of the background material when selecting appropriate severities of solar radiation for product applications. All types of geographical areas are covered, except areas with altitudes above 5 000 m. This second edition cancels and replaces the first edition published in 1987 and Amendment 1:1988. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- Figures updated including the addition of global irradiation information
- Format updated.
Classification des conditions d'environnement - Partie 2-4 : Conditions d'environnement présentes dans la nature - Rayonnement solaire et température
L’IEC 60721-2-4:2018 présente une large division en types de zones de rayonnement solaire. Elle est destinée à faire partie de la documentation de base pour choisir des sévérités appropriées de rayonnement solaire pour l'application aux produits. Tous les types de zones géographiques sont couverts, sauf les zones situées à plus de 5 000 m d’altitude. Cette deuxième édition annule et remplace la première édition parue en 1987 et l'Amendement 1:1988. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l’édition précédente:
- Mise à jour des figures incluant l’ajout d’informations sur l’exposition énergétique globale
- Mise à jour du format.
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IEC 60721-2-4 ®
Edition 2.0 2018-06
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Classification of environmental conditions –
Part 2-4: Environmental conditions appearing in nature – Solar radiation and
temperature
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
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About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.
About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
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IEC 60721-2-4 ®
Edition 2.0 2018-06
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Classification of environmental conditions –
Part 2-4: Environmental conditions appearing in nature – Solar radiation and
temperature
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 19.040 ISBN 978-2-8322-5847-7
– 2 – IEC 60721-2-4:2018 RLV © IEC 2018
CONTENTS
FOREWORD . 3
1 Scope . 5
Object .
2 Normative references. 5
3 Terms and definitions . 5
4 General . 5
5 Solar radiation physics . 6
6 Levels of global radiation . 7
6.1 Maximum levels . 7
6.2 Mean monthly and annual global solar radiation . 7
6.3 Simultaneous values of maximum air temperatures and solar radiation . 8
6.4 World distribution of daily global irradiation . 8
7 Minimum levels of atmospheric radiation at night . 8
Annex A (informative) World distribution of daily global irradiation . 11
Bibliography . 16
Figure – Atmospheric radiation from a clear night sky .
Figure 1 – Spectra of electromagnetic radiation from the Sun and the surface
of the Earth . 10
Figure A.1 – Mean relative global irradiation for the month of June (in %) . 13
Figure A.2 – Mean relative global irradiation for the month of December (in %) . 14
Figure A.3 – Mean relative global irradiation for the year (in %) . 15
Table 1 – Typical peak values of global irradiance (in W/m from a cloudless sky) . 7
Table A.1 – Mean daily extra-terrestrial global irradiation (kWh/m ) . 12
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CLASSIFICATION OF ENVIRONMENTAL CONDITIONS –
Part 2-4: Environmental conditions appearing in nature –
Solar radiation and temperature
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.
This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition. A vertical bar appears in the margin wherever a change
has been made. Additions are in green text, deletions are in strikethrough red text.
– 4 – IEC 60721-2-4:2018 RLV © IEC 2018
International Standard IEC 60721-2-4 has been prepared by IEC technical committee 104:
Environmental conditions, classification and methods of test.
This second edition cancels and replaces the first edition published in 1987 and
Amendment 1:1988. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Figures updated including the addition of global irradiation information,
b) Format updated.
The text of this International Standard is based on the following documents:
FDIS Report on voting
104/800/FDIS 104/803/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60721 series, published under the general title Classification of
environmental conditions, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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 publication using a colour printer.
CLASSIFICATION OF ENVIRONMENTAL CONDITIONS –
Part 2-4: Environmental conditions appearing in nature –
Solar radiation and temperature
1 Scope
This part of IEC 60721 presents a broad division into types of solar radiation areas. It is
intended to be used as part of the background material when selecting appropriate severities
of solar radiation for product applications.
All types of geographical areas are covered, except areas with altitudes above 5 000 m.
When selecting severities of solar radiation for product applications, the values which are
given in IEC 60721-1 should be applied.
2 Object
This document also serves to define limiting severities of solar radiation to which products are
liable to be exposed during transportation, storage and use.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 General
Solar radiation can affect products primarily by the heating of material and their environment
or by photochemical degradation of material.
The Solar radiation, especially its ultraviolet content of solar radiation, causes photochemical
degradation of most organic materials. Elasticity and plasticity of certain rubber compounds
and plastic materials are affected. Optical glass may become opaque.
Solar radiation bleaches out colours in paints, textiles, paper, etc. This can be of importance,
for example for the colour-coding of components.
The heating of material is the most important effect a consequence of exposure to solar
radiation. The presentation of severities of solar radiation is therefore related to the power
density radiated towards a surface, or irradiance, expressed in W/m .
– 6 – IEC 60721-2-4:2018 RLV © IEC 2018
An object subjected to solar radiation will attain a temperature that depends primarily on the
surrounding air temperature, the energy radiated from the Sun, and the incidence angle of the
radiation on the object. Other factors, for example wind and heat conduction to mountings,
can be of importance. In addition, the absorptance α of the surface for the solar spectrum
s
is of importance.
An artificial air temperature t may be defined, which, under steady-state conditions, results in
s
the same surface temperature of an object as the combination of the actual air temperature t
u
and the solar radiation of the irradiance E.
An approximate value can be obtained from the following equation:
α ⋅E
s
t =t +
s u
h
y
The co
...
IEC 60721-2-4 ®
Edition 2.0 2018-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Classification of environmental conditions –
Part 2-4: Environmental conditions appearing in nature – Solar radiation and
temperature
Classification des conditions d’environnement –
Partie 2-4: Conditions d'environnement présentes dans la nature – Rayonnement
solaire et température
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
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Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.
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.
IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing 21 000 terms and definitions in
Technical Specifications, Technical Reports and other English and French, with equivalent terms in 16 additional
documents. Available for PC, Mac OS, Android Tablets and languages. Also known as the International Electrotechnical
iPad. Vocabulary (IEV) online.
IEC publications search - webstore.iec.ch/advsearchform IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a 67 000 electrotechnical terminology entries in English and
variety of criteria (reference number, text, technical French extracted from the Terms and Definitions clause of
committee,…). It also gives information on projects, replaced IEC publications issued since 2002. Some entries have been
and withdrawn publications. collected from earlier publications of IEC TC 37, 77, 86 and
CISPR.
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IEC 60721-2-4 ®
Edition 2.0 2018-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Classification of environmental conditions –
Part 2-4: Environmental conditions appearing in nature – Solar radiation and
temperature
Classification des conditions d’environnement –
Partie 2-4: Conditions d'environnement présentes dans la nature – Rayonnement
solaire et température
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 19.040 ISBN 978-2-8322-5781-4
– 2 – IEC 60721-2-4:2018 © IEC 2018
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 General . 5
5 Solar radiation physics . 6
6 Levels of global radiation . 7
6.1 Maximum levels . 7
6.2 Mean monthly and annual global solar radiation . 7
6.3 Simultaneous values of maximum air temperatures and solar radiation . 8
6.4 World distribution of daily global irradiation . 8
7 Minimum levels of atmospheric radiation at night . 8
Annex A (informative) World distribution of daily global irradiation . 10
Bibliography . 15
Figure 1 – Spectra of electromagnetic radiation from the Sun and the surface
of the Earth . 9
Figure A.1 – Mean relative global irradiation for the month of June (in %) . 12
Figure A.2 – Mean relative global irradiation for the month of December (in %) . 13
Figure A.3 – Mean relative global irradiation for the year (in %) . 14
Table 1 – Typical peak values of global irradiance (in W/m from a cloudless sky) . 7
Table A.1 – Mean daily extra-terrestrial global irradiation (kWh/m ) . 11
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CLASSIFICATION OF ENVIRONMENTAL CONDITIONS –
Part 2-4: Environmental conditions appearing in nature –
Solar radiation and temperature
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.
International Standard IEC 60721-2-4 has been prepared by IEC technical committee 104:
Environmental conditions, classification and methods of test.
This second edition cancels and replaces the first edition published in 1987 and
Amendment 1:1988. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Figures updated including the addition of global irradiation information,
b) Format updated.
– 4 – IEC 60721-2-4:2018 © IEC 2018
The text of this International Standard is based on the following documents:
FDIS Report on voting
104/800/FDIS 104/803/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60721 series, published under the general title Classification of
environmental conditions, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
CLASSIFICATION OF ENVIRONMENTAL CONDITIONS –
Part 2-4: Environmental conditions appearing in nature –
Solar radiation and temperature
1 Scope
This part of IEC 60721 presents a broad division into types of solar radiation areas. It is
intended to be used as part of the background material when selecting appropriate severities
of solar radiation for product applications.
All types of geographical areas are covered, except areas wi
...
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