Classification of environmental conditions - Part 3-6: Classification of groups of environmental parameters and their severities - Ship environments

IEC 60721-3-6:2025 classifies the groups of environmental parameters and their severities to which a product is subjected when installed aboard a ship.
Ships where electrotechnical products may be permanently or temporarily installed include
- ships propelled by mechanical means, including mobile offshore units, and
- ships not propelled by mechanical means, including sailing boats and life rafts.
The classes defined apply to all sizes of ship from pleasure craft to trawlers, ferry boats, icebreakers, cargo ships including tankers.
The areas in which ships normally navigate are
- inland waterways (canals, rivers, lakes etc.),
- coastal waters, and
- oceans.
Areas where ships navigate in ice are also included.
This second edition cancels and replaces the first edition, published in 1987, and constitutes a technical revision.
This edition includes the following significant changes with respect to the previous edition:
a) most classes have been replaced by completely new classes based on the use of new information obtained from referenced Technical Reports;
b) Table 1 through to Table 5 have been updated;
c) the content of Annex A and Annex B has either been incorporated into main body text or deleted.

Classification des conditions d'environnement - Partie 3-6: Classification des groupements des agents d'environnement et de leurs sévérités - Environnement des navires

L'IEC 60721-3-6:2025 classifie les groupements des agents d'environnement et leurs sévérités, auxquels est soumis un produit lorsqu'il est installé à bord d'un navire.
Les navires à bord desquels des produits électrotechniques peuvent être installés de façon permanente ou temporaire comprennent:
- les navires à propulsion mécanique, y compris les unités mobiles en mer; et
- les navires non propulsés par des moyens mécaniques, y compris les bateaux à voile et les radeaux de survie.
Les classes définies s'appliquent aux navires de toutes tailles, depuis les embarcations de plaisance jusqu'aux chalutiers, transbordeurs, brise-glaces, cargos y compris les navires‑citernes.
Les zones dans lesquelles les navires naviguent normalement sont:
- les eaux intérieures (canaux, rivières, lacs, etc);
- les eaux côtières; et
- les océans.
Les zones où les navires naviguent dans les glaces sont aussi comprises.
Cette deuxième édition annule et remplace la première édition parue en 1987, et constitue une révision technique.
Cette édition inclut les modifications majeures suivantes par rapport à l'édition précédente:
a) la plupart des classes ont été remplacées par des classes totalement nouvelles, établies en fonction de l'utilisation de nouvelles informations obtenues dans les Rapports techniques référencés;
b) les Tableau 1 à Tableau 5 ont été mis à jour;
c) le contenu de l'Annexe A et de l'Annexe B a été soit incorporé dans le corps principal du texte, soit supprimé.

General Information

Status
Published
Publication Date
01-Jul-2025
Current Stage
PPUB - Publication issued
Start Date
02-Jul-2025
Completion Date
06-Jun-2025
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IEC 60721-3-6:2025 - Classification of environmental conditions - Part 3-6: Classification of groups of environmental parameters and their severities - Ship environments Released:2. 07. 2025 Isbn:9782832705131
English language
31 pages
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Standard
IEC 60721-3-6:2025 - Classification des conditions d'environnement - Partie 3-6: Classification des groupements des agents d'environnement et de leurs sévérités - Environnement des navires Released:2. 07. 2025 Isbn:9782832705131
French language
31 pages
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Standard
IEC 60721-3-6:2025 - Classification of environmental conditions - Part 3-6: Classification of groups of environmental parameters and their severities - Ship environments Released:2. 07. 2025 Isbn:9782832705131
English and French language
31 pages
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IEC 60721-3-6 ®
Edition 2.0 2025-07
INTERNATIONAL
STANDARD
Classification of environmental conditions -
Part 3-6: Classification of groups of environmental parameters and their
severities – Ship environments
ICS 19.040  ISBN 978-2-8327-0513-1

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or
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CONTENTS
FOREWORD . 2
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 General . 5
5 Classification of groups of environmental parameters and their severities . 6
5.1 General . 6
5.2 Climatic conditions (K) . 6
5.3 Biological conditions (B) . 10
5.4 Chemically active substances (C) . 10
5.5 Mechanically active substances (S) . 11
5.6 Mechanical conditions (M) . 12
Bibliography . 15

Figure 1 – Stationary vibration, sinusoidal . 14
Figure 2 – Non-stationary shock conditions . 14

Table 1 – Classification of climatic conditions . 8
Table 2 – Classification of biological conditions . 10
Table 3 – Classification of chemically active substances. 11
Table 4 – Classification of mechanically active substances . 12
Table 5 – Classification of mechanical conditions . 12

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Classification of environmental conditions -
Part 3-6: Classification of groups of environmental
parameters and their severities - Ship environments

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,
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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
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6) All users should ensure that they have the latest edition of this publication.
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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.
9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 60721-3-6 has been prepared by IEC technical committee 104: Environmental conditions,
classification and methods of test. It is an International Standard.
This second edition cancels and replaces the first edition, published in 1987, and constitutes a
technical revision.
This edition includes the following significant changes with respect to the previous edition:
a) most classes have been replaced by completely new classes based on the use of new
information obtained from referenced Technical Reports;
b) Table 1 through to Table 5 have been updated;
c) the content of Annex A and Annex B has either been incorporated into main body text or
deleted.
The text of this International Standard is based on the following documents:
Draft Report on voting
104/1094/FDIS 104/1113/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
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 webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
1 Scope
This part of IEC 60721 classifies the groups of environmental parameters and their severities
to which a product is subjected when installed aboard a ship.
Ships where electrotechnical products may be permanently or temporarily installed include
• ships propelled by mechanical means, including mobile offshore units, and
• ships not propelled by mechanical means, including sailing boats and life rafts.
The classes defined apply to all sizes of ship from pleasure craft to trawlers, ferry boats,
icebreakers, cargo ships including tankers.
The areas in which ships normally navigate are
• inland waterways (canals, rivers, lakes etc.),
• coastal waters, and
• oceans.
Areas where ships navigate in ice are also included.
The environmental conditions specified in this document are those that the product can be
exposed to whilst permanently or temporarily installed for the running, handling and safety of
the ship. The environmental conditions can also be used for other products, installed in a similar
way at similar locations.
Accidental incidents are not included but it can be important to take their occurrence into
account for products vital to the safety of the ship. The classification also does not cover the
effects of water pressure on submerged products.
Classification of storage and transportation environmental conditions are given in other
subparts of the IEC 60721-3 series.
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 60721-1, 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 terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
weatherprotected
protected from the influences of meteorological conditions
3.2
non-weatherprotected
not protected from the influences of meteorological conditions
4 General
A product can 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 on a product.
However, they do not provide information regarding the long-term or total lifetime environmental
stresses a product can experience. This means that no reliability or lifetime assessment is
possible based on these classes alone. Refer to the IEC 60721-2 series and applicable
technical reports (IEC TR 62130 and IEC TR 62131-8) for further information on actual
environmental conditions.
A product can be simultaneously exposed to a number of environmental parameters. For
example, solar radiation and temperature, temperature and humidity, as well as vibration and
temperature change. Combinations of the environmental parameters given can increase the
stress 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 environmental influences in two ways:
• by the effects of short-term extreme environmental conditions which can directly cause
malfunction or destroy the product;
• by the effect of long-term subjection to non-extreme environmental stresses which can
slowly degrade the product and finally cause malfunction or destruction of the product.
Short-term extreme environmental conditions can occur at any time in a product's life. A product
can 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 can affect the results of an evaluation.
It is important for the product specification, when referring to a certain class in the
IEC 60721-3 series, 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 the IEC 60721-3 series may
be used as a means 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 can exist which require
consideration of severities that are not addressed by this document.
5 Classification of groups of environmental parameters and their severities
5.1 General
A number of classes for climatic conditions (K), special climatic conditions (Z), biological
conditions (B), chemically active substances (C), mechanically active substances (S), and
mechanical conditions (M) are specified.
This classification allows for a number of possible combinations of environmental conditions
which bear upon products wherever geographically located. It represents the real situation
concerning worldwide conditions of use due to local influences. 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 as defined
in 5.2 through 5.6, for example:
6K13/6B2/6C6/6S6/6M6
5.2 Climatic conditions (K)
NOTE The classes defined in IEC 60721-3-6:1987 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 approp
...


IEC 60721-3-6 ®
Edition 2.0 2025-07
NORME
INTERNATIONALE
Classification des conditions d'environnement -
Partie 3-6: Classification des groupements des agents d'environnement et de
leurs sévérités - Environnement des navires
ICS 19.040  ISBN 978-2-8327-0513-1

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SOMMAIRE
AVANT-PROPOS . 2
1 Domaine d'application . 4
2 Références normatives . 4
3 Termes et définitions. 5
4 Généralités . 5
5 Classification des groupements des agents d’environnement et de leurs sévérités . 6
5.1 Généralités . 6
5.2 Conditions climatiques (K) . 6
5.3 Conditions biologiques (B) . 10
5.4 Substances chimiquement actives (C). 10
5.5 Substances mécaniquement actives (S) . 11
5.6 Conditions mécaniques (M) . 12
Bibliographie . 16

Figure 1 – Vibrations stationnaires, sinusoïdales . 14
Figure 2 – Conditions de choc non stationnaires . 15

Tableau 1 – Classification des conditions climatiques. 8
Tableau 2 – Classification des conditions biologiques . 10
Tableau 3 – Classification des substances chimiquement actives . 11
Tableau 4 – Classification des substances mécaniquement actives . 12
Tableau 5 – Classification des conditions mécaniques . 12

COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE
____________
Classification des conditions d'environnement -
Partie 3-6: Classification des groupements des agents
d’environnement et de leurs sévérités - Environnement des navires

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L'IEC ne saurait être tenue pour responsable de ne pas avoir identifié de tels droits de brevets.
L'IEC 60721-3-6 a été établie par le comité d’études 104 de l’IEC: Conditions, classification et
essais d'environnement. Il s'agit d'une Norme internationale.
Cette deuxième édition annule et remplace la première édition parue en 1987, et constitue une
révision technique.
Cette édition inclut les modifications majeures suivantes par rapport à l'édition précédente:
a) la plupart des classes ont été remplacées par des classes totalement nouvelles, établies en
fonction de l'utilisation de nouvelles informations obtenues dans les Rapports techniques
référencés;
b) les Tableau 1 à Tableau 5 ont été mis à jour;
c) le contenu de l'Annexe A et de l'Annexe B a été soit incorporé dans le corps principal du
texte, soit supprimé.
Le texte de cette Norme internationale est issu des documents suivants:
Projet Rapport de vote
104/1094/FDIS 104/1113/RVD
Le rapport de vote indiqué dans le tableau ci-dessus donne toute information sur le vote ayant
abouti à son approbation.
La langue employée pour l'élaboration de cette Norme internationale est l'anglais.
Ce document a été rédigé selon les Directives ISO/IEC, Partie 2, il a été développé selon les
Directives ISO/IEC, Partie 1 et les Directives ISO/IEC, Supplément IEC, disponibles sous
www.iec.ch/members_experts/refdocs. Les principaux types de documents développés par
l'IEC sont décrits plus en détail sous www.iec.ch/publications.
Une liste de toutes les parties de la série IEC 60721, publiées sous le titre général Classification
des conditions d'environnement, se trouve sur le site web de l'IEC.
Le comité a décidé que le contenu de ce document ne sera pas modifié avant la date de stabilité
indiquée sur le site web de l’IEC sous webstore.iec.ch dans les données relatives au document
recherché. À cette date, le document sera
• reconduit,
• supprimé, ou
• révisé.
1 Domaine d'application
La présente partie de l'IEC 60721 classifie les groupements des agents d'environnement et
leurs sévérités, auxquels est soumis un produit lorsqu'il est installé à bord d'un navire.
Les navires à bord desquels des produits électrotechniques peuvent être installés de façon
permanente ou temporaire comprennent:
• les navires à propulsion mécanique, y compris les unités mobiles en mer; et
• les navires non propulsés par des moyens mécaniques, y compris les bateaux à voile et les
radeaux de survie.
Les classes définies s'appliquent aux navires de toutes tailles, depuis les embarcations de
plaisance jusqu'aux chalutiers, transbordeurs, brise-glaces, cargos y compris les
navires-citernes.
Les zones dans lesquelles les navires naviguent normalement sont:
• les eaux intérieures (canaux, rivières, lacs, etc);
• les eaux côtières; et
• les océans.
Les zones où les navires naviguent dans les glaces sont aussi comprises.
Les conditions d'environnement spécifiées dans le présent document sont celles auxquelles le
produit peut être exposé lors d'une installation permanente ou temporaire pour le
fonctionnement, la manutention et la sécurité du navire. Les conditions d'environnement
peuvent également être utilisées pour d'autres produits, installés de manière similaire et dans
des endroits similaires.
Les incidents de nature accidentelle ne sont pas inclus, mais il peut être important de prendre
en compte leur occurrence dans le cadre des produits d'importance vitale pour la sécurité du
navire. La classification ne couvre pas non plus les effets de la pression de l'eau sur des
produits immergés.
La classification des conditions d'environnement pour le stockage et le transport est donnée
dans d'autres sous-parties de la série IEC 60721-3.
2 Références normatives
Les documents suivants sont cités dans le texte de sorte qu’ils constituent, pour tout ou partie
de leur contenu, des exigences du présent document. Pour les références datées, seule
l’édition citée s’applique. Pour les références non datées, la dernière édition du document de
référence s’applique (y compris les éventuels amendements).
IEC 60721-1, Classification des conditions d’environnement – Partie 1: Agents
d'environnement et leurs sévérités
3 Termes et définitions
Pour les besoins du présent document, les termes et définitions de l'IEC 60721-1 ainsi que les
suivants s'appliquent.
L’ISO et l’IEC tiennent à jour des bases de données terminologiques destinées à être utilisées
en normalisation, consultables aux adresses suivantes :
• IEC Electropedia: disponible à l’adresse https://www.electropedia.org/
• ISO Online browsing platform: disponible à l’adresse https://www.iso.org/obp
3.1
protégé contre les intempéries
protégé contre les influences des conditions météorologiques
3.2
non protégé contre les intempéries
non protégé contre les influences des conditions météorologiques
4 Généralités
Un produit peut être soumis à une grande variété de conditions d'environnement pendant sa
durée de vie. Ces conditions ont été séparées dans différentes classes, décrites dans
l'IEC 60721-3-0. Ces classes peuvent être utilisées pour définir les contraintes d'environnement
maximales à court terme sur un produit. Toutefois, elles ne fournissent pas d'informations sur
les contraintes d'environnement qu'un produit peut subir à long terme ou au cours de sa durée
de vie totale. Cela signifie qu'aucune évaluation de la fiabilité ou de la durée de vie n'est
possible en s'appuyant uniquement sur ces classes. Pour plus d'informations sur les conditions
d'environnement réelles, se reporter à la série IEC 60721-2 et aux rapports techniques
pertinents (IEC TR 62130 et IEC TR 62131-8).
Un produit peut être exposé simultanément à un certain nombre d'agents d'environnement. Par
exemple, le rayonnement solaire et la température, la température et l'humidité, ainsi que les
vibrations et les variations de température. Lorsqu'ils sont combinés, les agents
d'environnement indiqués peuvent accroître l'effet des contraintes sur un produit. Par
conséquent, il convient de prendre en compte ces conditions combinées lors de la conception
et de l'évaluation d'un produit.
Il convient de concevoir les produits afin qu'ils survivent et fonctionnent dans différents
environnements. Ces produits sont principalement affectés par les influences
environnementales de deux manières:
• par les effets de conditions d'environnement extrêmes à court terme qui peuvent
directement provoquer un dysfonctionnement ou détruire le produit;
• par l'effet d'une exposition à long terme à des contraintes d'environnement non extrêmes
qui peuvent provoquer une lente dégradation du produit et finalement occasionner un
dysfonctionnement ou une destruction du produit.
Des conditions d'environnement extrêmes à court terme peuvent survenir à tout moment du
cycle de vie du produit. Un produit peut ne pas être affecté par une condition extrême lorsqu'il
est neuf, mais peut présenter un dysfonctionnement lorsqu'il est soumis à la même condition
après une longue période d'utilisation en raison de l'effet du vieillissement. L'ordre dans lequel
les conditions d'environnement sont appliquées peut influencer les résultats d'une évaluation.
Il est important, dans la spécification du produit, lorsqu'il est fait référence à une certaine classe
de la série IEC 60721-3, de définir si le produit doit être capable de fonctionner ou uniquement
de survivre sans dommages permanents lorsqu'il est exposé aux conditions décrites par la
classe.
Les classes d'environnement peuvent être utilisées comme facteur déterminant pour le choix
des sévérités de conception et d'essai en fonction des conséquences d'une défaillance. Les
informations contenues dans la série IEC 60721-3 peuvent être utilisées pour faciliter la
définition des exigences prévues pour l'utilisation, le stockage, le transport, etc, ainsi que pour
l'élaboration des spécifications pertinentes. Il convient que les sévérités choisies et utilisées
pour les essais s'efforcent de produire les effets de l'environnement réel.
EXEMPLE 1 Un essai à haute température sur un produit dissipant la chaleur est conçu pour simuler l'effet
thermique d'un produit soumis à des conditions de température de l'air élevée, de rayonnement solaire et d'autres
sources de chaleur possibles en fonction de l'application.
EXEMPLE 2 Lors d'un essai de choc mécanique, le produit peut être soumis à des chocs mécaniques de formes
d'impulsions simples (par exemple, semi-sinusoïdales), alors que les conditions réelles ne peuvent pas être décrites
par des impulsions aussi simples.
Il est reconnu qu'il peut exister des conditions d'environnement extrêmes ou spéciales qui
exigent l'examen de sévérités qui ne sont pas traitées dans le présent document.
5 Classification des groupements des agents d’environnement et de leurs
sévérités
5.1 Généralités
Un certain nombre de classes pour les conditions climatiques (K), les conditions climatiques
spéciales (Z), les conditions biologiques (B), les substances chimiquement actives (C), les
substances mécaniquement actives (S) et les conditions mécaniques (M) sont spécifiées.
Cette classification permet d'établir un certain nombre de combinaisons possibles de conditions
d'environnement qui ont une influence sur les produits, quel que soit leur emplacement
géopgraphique. Elle représente la situation réelle pour des conditions universelles de utilisation
dues aux influences locales. Il n'a pas encore été possible de spécifier des valeurs quantitatives
de sévérité pour certains agents d'environnement.
Pour un produit ou un endroit donné, il convient de se référer à l'ensemble des classes définies
de 5.2 à 5.6, par exemple:
6K13/6B2/6C6/6S6/6M6
5.2 Conditions climatiques (K)
NOTE Les classes définies dans l'IEC 60721-3-6:1987 ont été remplacées par de nouvelles classes à la suite des
récentes initiatives de collecte d'informations sur les conditions climatiques. Ces résultats figurent dans les Rapports
techniques référencés dans le présent document.
Lors du choix des classes appropriées, il convient de tenir compte du fait que les conditions
climatiques dans les endroits protégés contre les intempéries peuvent dépendre des conditions
de l'air libre (non protégées contre les intempéries), en particulier la température de l'air et le
rayonnement solaire, ainsi que le type d'enceinte de transport.
Les conditions suivantes sont spécifiées dans le Tableau 1.
Endroits fermés sur les navires
6K8 couvre les endroits fermés complètement climatisés sur les navires. La température
de l'ai
...


IEC 60721-3-6 ®
Edition 2.0 2025-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Classification of environmental conditions -
Part 3-6: Classification of groups of environmental parameters and their
severities - Ship environments

Classification des conditions d'environnement -
Partie 3-6: Classification des groupements des agents d'environnement et de
leurs sévérités - Environnement des navires
ICS 19.040  ISBN 978-2-8327-0513-1

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CONTENTS
FOREWORD . 2
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 General . 5
5 Classification of groups of environmental parameters and their severities . 6
5.1 General . 6
5.2 Climatic conditions (K) . 6
5.3 Biological conditions (B) . 10
5.4 Chemically active substances (C) . 10
5.5 Mechanically active substances (S) . 11
5.6 Mechanical conditions (M) . 12
Bibliography . 15

Figure 1 – Stationary vibration, sinusoidal . 14
Figure 2 – Non-stationary shock conditions . 14

Table 1 – Classification of climatic conditions . 8
Table 2 – Classification of biological conditions . 10
Table 3 – Classification of chemically active substances. 11
Table 4 – Classification of mechanically active substances . 12
Table 5 – Classification of mechanical conditions . 12

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Classification of environmental conditions -
Part 3-6: Classification of groups of environmental
parameters and their severities - Ship environments

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
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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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
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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) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 60721-3-6 has been prepared by IEC technical committee 104: Environmental conditions,
classification and methods of test. It is an International Standard.
This second edition cancels and replaces the first edition, published in 1987, and constitutes a
technical revision.
This edition includes the following significant changes with respect to the previous edition:
a) most classes have been replaced by completely new classes based on the use of new
information obtained from referenced Technical Reports;
b) Table 1 through to Table 5 have been updated;
c) the content of Annex A and Annex B has either been incorporated into main body text or
deleted.
The text of this International Standard is based on the following documents:
Draft Report on voting
104/1094/FDIS 104/1113/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
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 webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
1 Scope
This part of IEC 60721 classifies the groups of environmental parameters and their severities
to which a product is subjected when installed aboard a ship.
Ships where electrotechnical products may be permanently or temporarily installed include
• ships propelled by mechanical means, including mobile offshore units, and
• ships not propelled by mechanical means, including sailing boats and life rafts.
The classes defined apply to all sizes of ship from pleasure craft to trawlers, ferry boats,
icebreakers, cargo ships including tankers.
The areas in which ships normally navigate are
• inland waterways (canals, rivers, lakes etc.),
• coastal waters, and
• oceans.
Areas where ships navigate in ice are also included.
The environmental conditions specified in this document are those that the product can be
exposed to whilst permanently or temporarily installed for the running, handling and safety of
the ship. The environmental conditions can also be used for other products, installed in a similar
way at similar locations.
Accidental incidents are not included but it can be important to take their occurrence into
account for products vital to the safety of the ship. The classification also does not cover the
effects of water pressure on submerged products.
Classification of storage and transportation environmental conditions are given in other
subparts of the IEC 60721-3 series.
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 60721-1, 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 terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
weatherprotected
protected from the influences of meteorological conditions
3.2
non-weatherprotected
not protected from the influences of meteorological conditions
4 General
A product can 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 on a product.
However, they do not provide information regarding the long-term or total lifetime environmental
stresses a product can experience. This means that no reliability or lifetime assessment is
possible based on these classes alone. Refer to the IEC 60721-2 series and applicable
technical reports (IEC TR 62130 and IEC TR 62131-8) for further information on actual
environmental conditions.
A product can be simultaneously exposed to a number of environmental parameters. For
example, solar radiation and temperature, temperature and humidity, as well as vibration and
temperature change. Combinations of the environmental parameters given can increase the
stress 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 environmental influences in two ways:
• by the effects of short-term extreme environmental conditions which can directly cause
malfunction or destroy the product;
• by the effect of long-term subjection to non-extreme environmental stresses which can
slowly degrade the product and finally cause malfunction or destruction of the product.
Short-term extreme environmental conditions can occur at any time in a product's life. A product
can 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 can affect the results of an evaluation.
It is important for the product specification, when referring to a certain class in the
IEC 60721-3 series, 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 the IEC 60721-3 series may
be used as a means 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 can exist which require
consideration of severities that are not addressed by this document.
5 Classification of groups of environmental parameters and their severities
5.1 General
A number of classes for climatic conditions (K), special climatic conditions (Z), biological
conditions (B), chemically active substances (C), mechanically active substances (S), and
mechanical conditions (M) are specified.
This classification allows for a number of possible combinations of environmental conditions
which bear upon products wherever geographically located. It represents the real situation
concerning worldwide conditions of use due to local influences. 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 as defined
in 5.2 through 5.6, for example:
6K13/6B2/6C6/6S6/6M6
5.2 Climatic conditions (K)
NOTE The classes defined in IEC 60721-3-6:1987 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 in weatherprotected locations can depend on the open-air (non-weatherprotected)
conditions, especially air temperature and solar radiation, and the type of transportation
enclosure.
The following conditions are specified in Table 1.
Enclosed ship locations
6K8 applies to fully air-conditioned enclosed ship locations. Air temperature and humidity
control is used continuously to maintain the required conditions.
6K9 applies to enclosed ship locations with limited temperature control and no humidity
control. This category encompasses locations which are weatherprotected, heated and
ventilated after warm-up. It also encompasses submerged products in all areas except
in those with high water temperature. It excludes machinery spaces and locations
containing machinery dissipating considerable heat. Also, the product should not
experience solar radiation through windows or other transparencies.
6K10 applies to enclosed ship locations without temperature and humidity controls in
unventilated enclosures in temperate, tropical and moderately cold climates. Polar
climate is excluded. This category includes machinery spaces and locations containing
machinery dissipating considerable heat. It excludes products which can experience
solar radiation through windows or other transparencies.
6K11 applies to enclosed ship locations without temperature and humidity controls in
unventilated enclosures in temperate, tropical, cold and polar climates. It includes
products which can experience solar radiation through windows or other
transparencies.
Sheltered ship locations
6K12 applies to weatherprotected ship locations in temperate, tropical, and moderate cold
climates. Polar climates are excluded. This category includes locations subject to solar
radiation and water jets but excludes areas with abnormal rain intensities.
6K13 applies to weatherprotected ship locations in temperate, tropical, cold and polar
climates. This category includes locations subject to solar radiation and water jets but
excludes areas with abnormal rain intensities.
Non-weatherprotected ship locations
6K14 applies to non-weatherprotected ship locations in tropical climates including coastal
regions adjacent to hot-arid locations. The product can be subjected to heavy seas,
impact by waves, high rain intensities and hurricanes, on open decks of ships.
6K15 applies to non-weatherprotected ship locations in temperate and moderately cold
climates. The product can be subjected to heavy seas, impact by waves and high rain
intensities on open decks of ships.
6K16 applies to non-weatherprotected ship locations in polar climates. The product can be
subjected to heavy seas, impact by waves and high rain intensities on open decks of
ships.
Table 1 – Classification of climatic conditions
Classification
Environmental parameter Unit Enclosed locations Sheltered locations Non-weatherprotected
6K8 6K9 6K10 6K11 6K12 6K13 6K14 6K15 6K16
f j k k
Low air temperature °C +5 –25 −45 −50 +5
+20 −45 −45 −50
i i
Low water temperature °C Freezing point of water +15 Freezing point of water
f g g g
High air temperature °C +40 +55 +70 +70 +70
+25 +45 +45 +50
High water temperature °C +35 +35 +35 +35 +35 +35 +35 +35 +35
l l l
High surface temperature °C None None None None None None
+70 +70 +70
a
°K/min 0,1 0,5 0,5 1,0 1,0 1,0 0,5 1,0 1,0
Rate of change of temperature (air)
b
% 20 5 5 10 4 4 30 4 4
Low relative humidity
b
% 75 85 85 100 100 100 100 100 100
High relative humidity
b 3
4 1 1 0,5 0,02 0,003 1 0,02 0,003
Low absolute humidity g/m
b 3
15 25 25 29 35 35 25 35 35
High absolute humidity g/m
c
kPa 70 70 70 70 70 70 70 70 30
Low air pressure
c
kPa 106 106 106 106 106 106 106 106 106
High air pressure
h h
Solar radiation No No No No No No 1090 1090 1090
W/m
Heat radiation Not specified None None None None None None None None None
d
m/s 0,5 1,0 1,0 1,0 30 30 50 50 50
Movement of surrounding air
Condensation Not specified No No No Yes Yes Yes Yes Yes Yes
Precipitation (rain, snow, hail, etc.) Not specified No No No No Yes Yes Yes Yes Yes
Rain intensity mm/min None None None None 3,3 3,3 3,3 3,3 3,3
Driving rain m/s None None None None 6 6 15 15 15
Snow load None None None None None None 100 100 100
kg/m
e
°C None None None None +5 +5 None +5 +5
Low rain temperature
Classification
Environmental parameter Unit Enclosed locations Sheltered locations Non-weatherprotected
6K8 6K9 6K10 6K11 6K12 6K13 6K14 6K15 6K16
Dripping Dripping Dripping
Water from sources other than rain m/s No No No 10 10 10
Water Water Water
Formation of ice and frost (including freeze-
Not specified No No No Yes Yes Yes Yes Yes Yes
thaw)
Temperature shock Not specified No No No Yes Yes Yes Yes Yes Yes
a
Averaged over a period of time of 5 min.
b
The low and high relative humidity levels are limited by the low and high absolute humidity, so that, for example, for environmental parameters low air temperature and low
relative humidity or high air temperature and high relative humidity, the severities given in Table 1 do not occur simultaneously.
c
The value of 70 kPa represents a limit for open-air conditions.
d
A cooling system based on non-assisted convection may be disturbed by adverse movement of surrounding air.
e
The cooling effect of rain can modify the surface temperature of the product.
f
These are air-conditioned locations with a tolerance of ±2 °C on stated temperature value.
g
Thermal effect of solar radiation is included in the temperature.
h
Thermal effect of solar radiation is not included in the temperature.
i
May be lower than 0°C because of the presence of salt or pollutants.
j
Products located in machinery spaces are only required to operate after a period of warm-up of the machinery space. For these products, the low temperature and the rate of
change of temperature only applies during non-operational state.
k
Ships may not necessarily navigate when air temperatures are below –40 °C. Products may, however, be left unprotected on ships which are temporarily laid up in harbour for
several years. In which case products in the non-operational state may have to withstand temperatures down to –55 °C. In exceptional inland waterways, ships may experience
temperatures below –40 °C.
l
More extreme surface temperatures may exist for example on machines.

5.3 Biological conditions (B)
No quantitative severity has been specified for the following conditions. The specified
parameters of Table 2 are typical but are not necessarily complete.
6B1 applies to areas without risks from mould growth and attack by animals, or in
compartments with environmental controls in place to prevent mould growth and attack
by animals.
6B2 applies areas in areas where mould growth and attacks of animals, except termites,
can occur.
Table 2 – Classification of biological conditions
Class
Biological parameter
6B1 6B2
Presence of mould, fungus,
Flora, in air
etc.
Negligible
Presence of rodents and other
Fauna, in air
animals harmful to products
Externally installed products on submerged parts of the hull will be subject to flora and
fauna of the water (algae, crustaceans, coral).

5.4 Chemically active substances (C)
NOTE The classes defined in IEC 60721-3-6:1987 have been replaced with new classes.
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 can affect the product’s function and
materials. The parameters shown in Table 3 are estimates based on information available at
the time of publication. It is recommended that reference be made to local or regional
information specific to an area of interest when establishing requirements.
6C4 applies to products within totally weatherprotected locations which are not subject to
salt mist and engine exhausts or emissions from nearby industrial sources. It also
encompasses conditions on decks (protected from engine exhaust) for ships confined
to inland fresh waters and not operated close to industries with considerable air
pollution.
6C5 in addition to the conditions covered by 6C4, 6C5 applies to products within totally
weatherprotected locations but which are subject to salt mist or engine exhausts, or
both.
6C6 in addition to the conditions covered by 6C5, 6C6 applies to products in non-
weatherprotected locations. It also encompasses conditions close to industries with
considerable air pollution.
The values given have been taken from surveys over several years. Maximum values are given,
because direct influence of higher concentrations over a short period of time normally causes
more damage to material which cannot regenerate. Mean values are given additionally, because
their influence can be important for the long-term effect on internal parts of the products. In
practice, not all contaminants (parameters) classified in this document are present
simultaneously. Furthermore, the probability is low that the concentrations of those
contaminants actually present increase simultaneously and homogeneously. Depending on the
local situation, there are often higher values of one contaminant only.
Table 3 – Classification of chemically active substances
Class
6C4 6C5 6C6
a
Environmental parameter
Unit
Maximum Maximum
Maximum
Mean value Mean value
b b
value value
value
c d
Substances in air
Salt mist None No Yes Yes
Sulphur dioxide 0,1 0,3 1,0 5,0 10
mg/m
3 3
0,037 0,11 0,37 1,85 3,7
cm /m
Hydrogen sulphide 0,01 0,1 0,5 3,0 10
mg/m
3 3
0,0071 0,071 0,36 2,1 7,1
cm /m
Hydrogen chloride 0,1 0,1 0,5 1,0 5,0
mg/m
3 3
0,066 0,066 0,33 0,66 3,3
cm /m
Hydrogen fluoride 0,003 0,01 0,03 0,1 2,0
mg/m
3 3
0,0036 0,012 0,036 0,12 2,4
cm /m
Ammonia 0,3 1,0 3,0 10 35
mg/m
3 3
0,42 1,4 4,2 14 49
cm /m
Nitrogen oxides (expressed 0,1 0,5 1,0 3,0 9,0
mg/m
in equivalent values of
3 3
0,052 0,26 0,52 1,56 4,68
nitrogen dioxide) cm /m
e
Substances in wate
h) Sea salts Negligible Negligible 30
kg/m
a 3 3 3
The values given in cm /m have been calculated from the values given in mg/m referenced to a temperature
of 20 °C and a pressure of 101,3 kPa. The table uses rounded values.
b
Mean values are expected long-term values. Maximum values are limit or peak values occurring over a period
of time that is typically not more than 30 min per day.
c
Other substances and severities may occur due to a specific cargo carried. For tankers, reference is made to
IEC 60092-502.
d
Explosive atmosphere is outside the scope of this document.
e
Substances in sea water other than sea salt are not included, as they are considered to have negligible effect
on electro-technical products already protected from the effects of sea water.

5.5 Mechanically active substances (S)
NOTE The classes defined in IEC 60721-3-6:1987 have been replaced with new classes as a result of recent efforts
at collecting information regarding mechanically active substances.
Dust and sand are classified together, as the effects caused by these environmental conditions
are similar. These conditions are specified in Table 4.
6S4 applies to products in locations protected from dust, sand and ingress of soot.
6S5 applies to products in locations which are weatherprotected and non-weatherprotected
where sweeping of dusty decks may take place. It also covers locations subject to
emissions from boiler exhaust.
6S6 applies to products in locations which are non-weatherprotected including ships
operating close to deserts.
Table 4 – Classification of mechanically active substances
Class
Environmental parameter Unit
6S4 6S5 6S6
Sand in air None 30 300
mg/m
Dust in air None 0,2 5,0
mg/m
Dust (sedimentation rate) None 15 40
mg/(m ⋅h)
Soot deposit None No Yes
Other severities of dust and sand can occur due to specific cargoes when they contain dusty material and sand
(including abrasive substances).

5.6 Mechanical conditions (M)
NOTE The classes defined in IEC 60721-3-6:1987 have been replaced with new classes as a result of recent efforts
at collecting information regarding mechanical conditions. Those results are contained in Technical Reports
referenced in this document.
Mechanical conditions described in this document encompass those conditions that can exist
on or within ships and are described in Table 5. The conditions do not represent test severities.
Vibration and mechanical shock environments are depicted in Figure 1 and Figure 2,
respectively.
6M5 applies to installations in ships which are not powered by engines.
6M6 applies to installations in engine-powered ships larger than 1 000 tonnes dead weight
except for stern locations in ships smaller than 20 000 tonnes dead weight.
6M7 applies to installations in engine-powered ships smaller than 1 000 tonnes dead weight
and stern locations in ships smaller than 20 000 tonnes dead weight. Also includes
products connected directly to loading systems, container guides, cranes and
installations in dredgers.
6M8 applies to products installed directly to reciprocating machinery.
Table 5 – Classification of mechanical conditions
Class
Environmental
Unit
parameter
6M5 6M6 6M7 6M8
a b
Stationary vibration, sinusoidal :
Displacement
mm None 1,5 - 1,5 - 1,5 -
amplitude
acceleration
None - 10 - 20 - 50
m/s
amplitude
2 to 13 to 18 to
frequency range Hz None 2 to 18 2 to 28 28 to 200
13 100 200
c
Non-stationary vibration including shock :
d
Figure 2, curve 1 Figure 2, curve 3 Figure 2, curve 3 Figure 2, curve 3
Shock 1
(equivalent to a (equivalent to a (equivalent to a (equivalent to a half
half sine pulse of half sine pulse of half sine pulse of sine pulse of
2 2 2 2
50 m/s and 100 m/s and 100 m/s and 100 m/s and 11 ms
11 ms duration) 11 ms duration) 11 ms duration) duration)
Class
Environmental
Unit
parameter
6M5 6M6 6M7 6M8
d
Figure 2, curve 2 Figure 2, curve 4 Figure 2, curve 4 Figure 2, curve 4
Shock 2
(equivalent to a (equivalent to a (equivalent to a (equivalent to a half
half sine pulse of
half sine pulse of half sine pulse of sine pulse of
2 2 2 2
100 m/s and 300 m/s and 300 m/s and 6 ms 300 m/s and 6 ms
6 ms duration) 6 ms duration) duration) duration)
e
Angular deviation, static condition :
Rotation angle about
degrees 15 15 15 15
X-axis (list)
Rotation angle about
degrees 10 10 10 10
Y-axis (trim)
e
Angular motion, dynamic condition :
Rotation about X-axis (roll)
angle degrees 22,5 22,5 22,5 22,5
frequency Hz 0,14 0,14 0,14 0,14
Rotation about Y-axis (pitch)
angle degrees 10 10 10 10
frequency Hz 0,2 0,2 0,2 0,2
Rotation about Z-axis (yaw)
angle degrees 4 4 4 4
frequency Hz 0,05 0,05 0,05 0,05
e
Steady-state acceleration :
X-direction (surge) 5 5 5 5
m/s
Y- direction (sway) 6 6 6 6
m/s
Z-direction (heave) 10 10 10 10
m/s
Static load
Static load kPa None 5 10 10
a
Vibration generated by ships' engines and machinery is mainly of a complex sinusoidal nature, with pronounced
low frequency content. High frequency vibrations, up to 2 000 Hz may, however, be present on some ships when
sources of vibration, other than ships' engines and machinery, are predominant. IEC TR 62131-8 and
IEC 60721-3-2 provide alternative random vibration severities.
b
Vibration severities on ice breakers can exceed those quoted here.
c
These shocks can occur simultaneously with the stationary vibration random conditions.
d
Both shocks would normally be used to encompass different aspects of the shock environment.
e
The three orthogonal axes related to ships are X = fore and aft, Y = athwart, Z = vertical.

Figure 1 – Stationary vibration, sinusoidal

Figure 2 – Non-stationary shock conditions

Bibliography
IEC 60092-502, Electrical installations in ships – Tankers – Special features
IEC 60721-2 (all parts), Classification of environmental conditions – Part 2: Environmental
conditions appearing in nature
IEC 60721-3 (all parts), Classification of environmental conditions – Part 3: Classification of
groups of environmental parameters and their severities
IEC 60721-3-0, Classification of environmental conditions – Part 3-0: Classification of groups
of environmental parameters and their severities – Introduction
IEC 60721-3-2, Classification of environmental conditions – Part 3-2 Classification of groups of
environmental parameters and their severities – Transportation and handling
IEC 60721-3-6:1987, Classification of environmental conditions. Part 3: Classification of groups
of environmental parameters and their severities – Ship environment
IEC TR 62130, Climatic field data including validation
IEC TR 62131-8, Environmental conditions – Vibration and shock of electrotechnical equipment
– Part 8: Transportation by ship

___________
SOMMAIRE
AVANT-PROPOS . 2
1 Domaine d'application . 4
2 Références normatives . 4
3 Termes et définitions. 5
4 Généralités . 5
5 Classification des groupements des agents d’environnement et de leurs sévérités . 6
5.1 Généralités . 6
5.2 Conditions climatiques (K) . 6
5.3 Conditions biologiques (B) . 10
5.4 Substances chimiquement actives (C). 10
5.5 Substances mécaniquement actives (S) . 11
5.6 Conditions mécaniques (M) . 12
Bibliographie . 16

Figure 1 – Vibrations stationnaires, sinusoïdales . 14
Figure 2 – Conditions de choc non stationnaires . 15

Tableau 1 – Classification des conditions climatiques. 8
Tableau 2 – Classification des conditions biologiques . 10
Tableau 3 – Classification des substances chimiquement actives . 11
Tableau 4 – Classification des substances mécaniquement actives . 12
Tableau 5 – Classification des conditions mécaniques . 12

COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE
____________
Classification des conditions d'environnement -
Partie 3-6: Classification des groupements des agents
d’environnement et de leurs sévérités - Environnement des navires

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