IEC 60721-3-4:2019

Classification of environmental conditions - Part 3-4: Classification of groups of environmental parameters and their severities - Stationary use at non-weatherprotected locations

IEC 60721-3-4:2019

Name:IEC 60721-3-4:2019   Standard name:Classification of environmental conditions - Part 3-4: Classification of groups of environmental parameters and their severities - Stationary use at non-weatherprotected locations
Standard number:IEC 60721-3-4:2019   language:English and French language
Release Date:21-May-2019   technical committee:TC 104 - Environmental conditions, classification and methods of test
Drafting committee:MT 19 - TC 104/MT 19   ICS number:01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION

IEC 60721-3-4
Edition 3.0 2019-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Classification of environmental conditions –
Part 3-4: Classification of groups of environmental parameters and their
severities – Stationary use at non-weatherprotected locations

Classification des conditions d'environnement –
Partie 3-4: Classification des groupements des agents d'environnement et de
leurs sévérités – Utilisation à poste fixe, non protégé contre les intempéries





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IEC 60721-3-4
Edition 3.0 2019-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Classification of environmental conditions –

Part 3-4: Classification of groups of environmental parameters and their

severities – Stationary use at non-weatherprotected locations

Classification des conditions d'environnement –

Partie 3-4: Classification des groupements des agents d'environnement et de

leurs sévérités – Utilisation à poste fixe, non protégé contre les intempéries

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 19.040 ISBN 978-2-8322-6956-5

– 2 – IEC 60721-3-4:2019 © 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) . 8
(informative) Interdependence of air temperature, relative air humidity, and
absolute air humidity . 12
(informative) Definition of seismic environment . 13
Bibliography . 15

Figure A.1 – Climatogram of interdependence of air temperature, relative air humidity,
and absolute air humidity . 12

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 . 11
Table B.1 – Correlation of seismic zones with expected magnitudes . 14

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CLASSIFICATION OF ENVIRONMENTAL CONDITIONS –

Part 3-4: Classification of groups of environmental parameters and
their severities – Stationary use at non-weatherprotected locations

FOREWORD
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International Standard IEC 60721-3-4 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 1995 and
Amendment 1:1996. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Clause 1: reworded.
b) Clause 2: normative references have been updated.
c) Clause 3: definitions have been updated.
d) Clause 4: reworded and simplified.

– 4 – IEC 60721-3-4:2019 © IEC 2019
e) Clause 5: revised and updated. Several classes have been replaced by completely new
classes based on the use of new information obtained from referenced technical reports.
f) Defined values of chemically active substances are now by reference to ISO 9223.
g) Tables 1 through 5: updated.
The text of this International Standard is based on the following documents:
FDIS Report on voting
104/828/FDIS 104/836/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.
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