Classification of environmental conditions - Part 3-3: Classification of groups of environmental parameters and their severities - Stationary use at weatherprotected locations

IEC 60721-3-3:2019 classifies groups of environmental parameters and their severities to which products are subjected when installed for stationary use at weatherprotected locations.
This third edition cancels and replaces the second edition published in 1994, Amendment 1: 1995 and Amendment 2:1996. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) Clause 3: definitions aligned with IEC 60721-3-1.
b) Clause 4: aligned with IEC 60721-3-1.
c) Clause 5: Clause A.3 has been incorporated into Clause 5.
d) Subclause 5.2: all existing climate classes have been replaced by completely new classes. The new classes are divided into two groups. The reason for the new classes is the latest revision of IEC 60721-2-1 which incorporates new climate types.
e) Subclause 5.3: addition of a new class for low air pressure.
f) Defined values of chemically active substances are now by reference to ISO 9223.
g) Subclause 5.6: all existing classes for mechanically active substances have been replaced by completely new classes, in alignment with IEC 60721-3-1.
h) Subclause 5.7: all existing classes for mechanical conditions have been replaced by completely new classes, in alignment with IEC 60721-3-1.
i) Table 1: new climatic classes with new severities.
j) Table 2: new class for low air pressure.
k) Table 4: new mechanically active substances classes.
l) Table 5: new mechanical conditions classes.
m) Annex A: revised and includes a clean climatogram.
n) Annex B: revised and includes the definition of seismic environment.
o) All classes regarding fire, all combined classes, all chemically active substances classes, Clause A.2, Annexes C, D and E have been removed.

Classification des conditions d'environnement - Partie 3-3: Classification des groupements des agents d'environnement et de leurs sévérités - Utilisation à poste fixe, protégé contre les intempéries

L’IEC 60721-3-3:2019 classifie les groupements d’agents d’environnement et leurs sévérités, auxquels sont soumis des produits montés pour une utilisation à poste fixe dans des emplacements protégés contre les intempéries.
Cette troisième édition annule et remplace la deuxième édition parue en 1994, ainsi que son amendement 1:1995 et son amendement 2:1996. Cette édition constitue une révision technique.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) Article 3: alignement des définitions sur l’IEC 60721-3-1.
b) Article 4: alignement sur l’IEC 60721-3-1.
c) Article 5: intégration de l'Article A.3 dans l’Article 5.
d) Paragraphe 5.2: toutes les catégories climatiques ont été remplacées par des catégories totalement nouvelles. Ces nouvelles catégories sont divisées en deux groupes. La création de nouvelles catégories est justifiée par la dernière révision de l’IEC 60721-2-1 qui intègre de nouveaux types de climats.
e) Paragraphe 5.3: ajout d'une nouvelle catégorie pour la basse pression atmosphérique.
f) Les valeurs définies des substances chimiquement actives font désormais référence à l’ISO 9223.
g) Paragraphe 5.6: toutes les catégories existantes pour les substances mécaniquement actives ont été remplacées par des catégories totalement nouvelles, avec alignement sur l’IEC 60721-3-1.
h) Paragraphe 5.7: toutes les catégories existantes pour les conditions mécaniques ont été remplacées par des catégories totalement nouvelles, avec alignement sur l’IEC 60721-3-1.
i) Tableau 1: nouvelles catégories climatiques avec de nouvelles sévérités.
j) Tableau 2: nouvelle catégorie pour la basse pression atmosphérique.
k) Tableau 4: nouvelles catégories pour les substances mécaniquement actives.
l) Tableau 5: nouvelles catégories pour les conditions mécaniques.
m) Annexe A: révision et introduction d'un climatogramme propre.
n) Annexe B: révision et introduction de la définition de l'environnement sismique.
o) Toutes les catégories relatives au feu, toutes les catégories combinées, toutes les catégories des substances chimiquement actives, l'Article A.2, les Annexes C, D et E ont été supprimés.

General Information

Status
Published
Publication Date
21-May-2019
Current Stage
PPUB - Publication issued
Completion Date
22-May-2019
Ref Project

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IEC 60721-3-3
Edition 3.0 2019-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Classification of environmental conditions –
Part 3-3: Classification of groups of environmental parameters
and their severities – Stationary use at weatherprotected locations
Classification des conditions d'environnement –
Partie 3-3: Classification des groupements des agents d'environnement et de
leurs sévérités – Utilisation à poste fixe, protégé contre les intempéries
IEC 60721-3-3:2019-05(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60721-3-3
Edition 3.0 2019-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Classification of environmental conditions –
Part 3-3: Classification of groups of environmental parameters
and their severities – Stationary use at weatherprotected locations
Classification des conditions d'environnement –
Partie 3-3: Classification des groupements des agents d'environnement et de
leurs sévérités – Utilisation à poste fixe, protégé contre les intempéries
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 19.040 ISBN 978-2-8322-6954-1

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 60721-3-3:2019 © IEC 2019
CONTENTS

FOREWORD ........................................................................................................................... 3

1 Scope .............................................................................................................................. 5

2 Normative references ....................................................................................................... 5

3 Terms and definitions....................................................................................................... 5

4 General ........................................................................................................................... 6

5 Classification of groups of environmental parameters and their severities ......................... 7

5.1 General ................................................................................................................... 7

5.2 Climatic conditions (K) ............................................................................................ 7

5.3 Special climatic conditions (Z) ................................................................................. 8

5.4 Biological conditions (B) .......................................................................................... 8

5.5 Chemically active substances (C) ............................................................................ 8

5.6 Mechanically active substances (S) ......................................................................... 8

5.7 Mechanical conditions (M) ....................................................................................... 9

Annex A (informative) Interdependence of air temperature, relative air humidity, and

absolute air humidity ............................................................................................................. 11

Annex B (informative) Definition of seismic environment ....................................................... 12

Bibliography .......................................................................................................................... 14

Figure A.1 – Climatogram of interdependence of air temperature, relative air humidity,

and absolute air humidity ....................................................................................................... 11

Table 1 – Classification of climatic conditions .......................................................................... 9

Table 2 – Classification of special climatic conditions ............................................................ 10

Table 3 – Classification of biological conditions ..................................................................... 10

Table 4 − Classification of mechanically active substances .................................................... 10

Table 5 − Classification of mechanical conditions .................................................................. 10

Table B.1 – Correlation of seismic zones with expected magnitudes ...................................... 13

---------------------- Page: 4 ----------------------
IEC 60721-3-3:2019 © IEC 2019 − 3 −
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CLASSIFICATION OF ENVIRONMENTAL CONDITIONS –
Part 3-3: Classification of groups of environmental parameters
and their severities – Stationary use at weatherprotected locations
FOREWORD

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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.

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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60721-3-3 has been prepared by IEC technical committee 104:

Environmental conditions, classification, and methods of test.

This third edition cancels and replaces the second edition published in 1994, Amendment 1:

1995 and Amendment 2:1996. This edition constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:
a) Clause 3: definitions aligned with IEC 60721-3-1.
b) Clause 4: aligned with IEC 60721-3-1.
c) Clause 5: Clause A.3 has been incorporated into Clause 5.
---------------------- Page: 5 ----------------------
– 4 – IEC 60721-3-3:2019 © IEC 2019

d) Subclause 5.2: all existing climate classes have been replaced by completely new classes.

The new classes are divided into two groups. The reason for the new classes is the latest

revision of IEC 60721-2-1 which incorporates new climate types.
e) Subclause 5.3: addition of a new class for low air pressure.

f) Defined values of chemically active substances are now by reference to ISO 9223.

g) Subclause 5.6: all existing classes for mechanically active substances have been replaced

by completely new classes, in alignment with IEC 60721-3-1.

h) Subclause 5.7: all existing classes for mechanical conditions have been replaced by

completely new classes, in alignment with IEC 60721-3-1.
i) Table 1: new climatic classes with new severities.
j) Table 2: new class for low air pressure.
k) Table 4: new mechanically active substances classes.
l) Table 5: new mechanical conditions classes.
m) Annex A: revised and includes a clean climatogram.
n) Annex B: revised and includes the definition of seismic environment.

o) All classes regarding fire, all combined classes, all chemically active substances classes,

Clause A.2, Annexes C, D and E have been removed.
The text of this International Standard is based on the following documents:
FDIS Report on voting
104/829/FDIS 104/837/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.
---------------------- Page: 6 ----------------------
IEC 60721-3-3:2019 © IEC 2019 − 5 −
CLASSIFICATION OF ENVIRONMENTAL CONDITIONS –
Part 3-3: Classification of groups of environmental parameters
and their severities – Stationary use at weatherprotected locations
1 Scope

This part of IEC 60721 classifies groups of environmental parameters and their severities to

which products are subjected when installed for stationary use at weatherprotected locations.

The environmental conditions specified in this document are limited to those which can directly

affect the performance of products. Only environmental conditions as such are considered. No

special description of the effects of these conditions on the products is provided.

Environmental conditions directly related to explosion hazards, microclimate within a product,

fire extinction and ionizing radiation are excluded. Any other unforeseen incidents are also

excluded. The possibility of their occurrence can be considered as special cases. This

document does not cover equipment covered by building standards, codes or regulations.

Conditions of stationary use at non-weatherprotected locations, portable and non-stationary

use, use in vehicles and ships, conditions of storage and transportation, and microclimates

inside products are given in other parts of the IEC 60721-3 series.

A limited number of classes of environmental conditions is given, covering a broad field of

applications.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their

content constitutes requirements 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 60721-3-0, Classification of environmental conditions − Part 3: Classification of groups of

environmental parameters and their severities − Introduction

IEC 60721-1, Classification of environmental conditions − Part 1: Environmental parameters

and their severities
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 60721-1 and the

following apply.

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
---------------------- Page: 7 ----------------------
– 6 – IEC 60721-3-3:2019 © IEC 2019
3.1
stationary use

use of a product mounted firmly on a structure, or permanently placed at a certain site

3.2
weatherprotected location

location at which a product is protected from direct exposure to meteorological conditions

4 General

A product may be subjected to a range of environmental conditions during its lifetime. These

conditions have been separated into classes described in IEC 60721-3-0. The classes given

may be used for defining the maximum short-term environmental stresses of a product.

However, they do not provide information regarding the long-term or total lifetime

environmental stresses a product may experience. This means that no reliability or lifetime

assessment is possible based on these classes alone. Refer to IEC 60721-2 (all parts) and

applicable technical reports (IEC TR 62130 and IEC TR 62131-5) for further information on

actual environmental conditions.

A product will be simultaneously exposed to a number of environmental parameters, for

example, low air pressure and temperature, temperature and humidity, as well as vibration and

temperature change. Combinations of the environmental parameters given may increase the

effect on a product. Therefore, combined conditions should be considered in the design and

evaluation of a product.

Products should be designed to survive and operate in different environments. Basically, they

will be affected by the environmental influences in two ways:

– by the effects of short-term extreme environmental conditions which may directly cause

malfunction or destroy the product;

– by the effect of long-term subjection to non-extreme environmental stresses which may

slowly degrade the product and finally cause malfunction or destruction of the product.

Short-term extreme environmental conditions may occur at any time in the product's life. A

product may be unaffected by an extreme condition when it is new but fail when it is subjected

to the same condition after being used for a long period of time due to the effect of ageing. The

order in which the environmental conditions are applied may affect the results of an evaluation.

It is important for the product specification, when referring to a certain class in IEC 60721-3 (all

parts), to define whether the product is required to be capable of operating or only to survive

without permanent damage when being exposed to the conditions described by the class.

The environmental classes may be used as a basis for the selection of design and test

severities with respect to the consequence of failure. Information contained in IEC 60721-3 (all

parts) may be used to help establish expected requirements for use, storage, transportation,

etc., and in the development of relevant specifications. The selected severities used for testing

should attempt to produce the effects of the actual environment.

EXAMPLE 1 A high temperature test on a heat dissipating product is designed to simulate the thermal effect of

subjecting a product to conditions of high air temperature, solar radiation and other possible heat sources

dependent on the application.

EXAMPLE 2 In a mechanical shock test, the product can be subjected to mechanical shocks of simple pulse

shapes (e.g., half-sine), while the actual conditions cannot be described by such simple pulses.

It is recognized that extreme or special environmental conditions may exist which require

consideration of severities that are not addressed in this document. The user of this document

should select the lowest classification necessary for covering the conditions of the intended

use.
---------------------- Page: 8 ----------------------
IEC 60721-3-3:2019 © IEC 2019 − 7 −
5 Classification of groups of environmental parameters and their severities
5.1 General

Several classes for climatic conditions (K), special climatic conditions (Z), biological

conditions (B), mechanically active substances (S), and mechanical conditions (M) are

specified.

This classification allows for several possible combinations of environmental conditions which

bear upon products wherever in use. It represents the real situation in respect of world-wide

conditions of use, due to local influences of open-air climate, construction of buildings,

mounting, process conditions, etc.

For certain environmental parameters, it has not yet been possible to specify quantitative

severities.

For a given location or product, reference should be made to the total set of classes, for

example:
3K21/3Z1/3B1/3S6/3M11
5.2 Climatic conditions (K)

The classes defined in previous versions of this document have been replaced with new

classes as a result of recent efforts at collecting information regarding climatic conditions.

Those results are contained in technical reports referenced in this document.

When selecting appropriate classes, attention should be paid to the fact that the climatic

conditions inside buildings may depend on the outside (open-air) conditions, especially air

temperature and solar radiation, and the type of building construction. Walls with good thermal

insulation or high thermal capacity can consistently smooth the peaks of outside air

temperature variations between day and night, or, exceptionally, those produced over a longer

period of time. Walls with poor thermal insulation or low thermal capacity cannot have this

effect and peaks can be magnified due to the effect of solar radiation during the day, and to the

effect of building radiation at night. The effect of solar radiation can be increased by either

heat-trap or greenhouse effects.

The climatic conditions specified for classes 3K20 to 3K24 refer to the conditions in use of the

products. These conditions have been experienced world-wide over a long period of time taking

into account all the parameters that can influence them, such as open-air climatic conditions,

type of building construction, temperature/humidity controlling systems, and internal conditions,

for example heat dissipation from other equipment, presence of humans. The conditions should

cover all normal cases, but not exceptional events. These conditions are specified in Table 1.

The interdependence of temperature to relative humidity is shown in Annex A.
Enclosed locations

– 3K20 applies to fully air-conditioned enclosed locations. Air temperature and humidity

control is used continuously to maintain the required conditions.

– 3K21 applies to continuously temperature-controlled enclosed locations. Humidity is not

normally controlled.

Heating, cooling or humidification is used where necessary to maintain the required

conditions, especially where there is a large difference between them and the open-air

climate. Installed products may be exposed to secondary effects of solar radiation due to

increased ambient temperature and to heat radiation. They may also be exposed to

movements of surrounding air due to draughts in buildings, for example through open

windows, or due to special process conditions.
---------------------- Page: 9 ----------------------
– 8 – IEC 60721-3-3:2019 © IEC 2019

The conditions of this class may be found in continuously manned offices, workshops, data

centres and other rooms for special applications.

– 3K22 applies to temperature-controlled enclosed locations. Humidity is not controlled.

Heating or cooling is used to maintain the required conditions, especially where there is a

large difference between them and the open-air climate.

The conditions of this class may be found in normal living or working areas, for example

living rooms, rooms for general use (theatres, restaurants, etc.), offices, shops, workshops

for electronic assemblies and other electrotechnical products, telecommunication centres,

storage rooms for valuable and sensitive products.
– 3K23 applies to enclosed locations having no temperature or humidity control.

Heating may be used to raise low temperatures, especially where there is a large difference

between the conditions of this class and the open-air climate.
Installed products may be subjected to formation of ice.

The conditions of this class may be found in some entrances and staircases of buildings, in

garages, cellars, certain workshops, buildings in factories and industrial process plants,

unattended equipment stations, certain telecommunication buildings, ordinary storage

rooms for frost-resistant products, farm buildings, etc.
– 3K24 applies to locations having neither temperature nor humidity control.

The location may have openings directly to the open air. The climatic conditions of this

class may be affected to a varying extent by the conditions of the open-air climate and the

construction of the building.
Installed products may be subjected to formation of ice.

The conditions of this class may be found in entrances to buildings, in garages, shacks,

unattended buildings, etc.
5.3 Special climatic conditions (Z)

Parameters such as heat radiation, and air pressure may occur with any severity in

combination with any of the other climatic conditions. These conditions are specified in Table 2.

5.4 Biological conditions (B)

No quantitative severity has been specified for these conditions. These conditions are specified

in Table 3. The specified parameters are typical but may not be complete.

– 3B1 applies to locations with environmental controls in place to prevent the growth of mould

and physical controls are in place to prevent attacks by animals.

– 3B2 applies to locations without environmental or physical controls in place to prevent

mould growth or attacks by animals, except termites.

– 3B3 applies to locations where attacks by termites or similar fauna may occur.

5.5 Chemically active substances (C)

The contamination of the natural atmosphere is mainly caused by chemical emissions from

industrial activities, motor-driven vehicles, and heating systems. A further chemical influence is

caused by aerosols of sea and road salts. Contamination may affect the function and materials

of products. Additional details regarding the categorization of these conditions may be found in

ISO 9223.
5.6 Mechanically active substances (S)

Dust and sand are classified together, as the effects caused by these environmental conditions

are similar. These conditions are specified in Table 4.

– 3S5 applies to locations where precautions have been taken to minimize the presence of

dust and sand. Ingress of sand is prevented.
---------------------- Page: 10 ----------------------
IEC 60721-3-3:2019 © IEC 2019 − 9 −

– 3S6 applies to locations not situated in proximity to dust or sand sources and with no

special precautions to minimize the ingress of dust or sand.

– 3S7 applies to enclosed locations in close proximity to sand or dust sources, including

urban areas and with no special precautions to minimize the ingress of dust or sand.

5.7 Mechanical conditions (M)

Mechanical conditions relate to the levels of vibration and shock that may exist at the location,

for example as a result of normal operations, nearby vehicular movement. These conditions

are specified in Table 5. See Annex B for the definition of seismic environment.

– 3M10 applies to locations experiencing insignificant levels of vibration and shock.

– 3M11 applies to locations experiencing low levels of vibration and insignificant levels of

shock, such as those transmitted from air conditioning, machines or passing vehicles in the

vicinity.
– 3M12 applies
...

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