SIST EN IEC 60721-3-3:2019/kFprA1:2026

• Status: Not Published
• Public Enquiry End Date: 22-May-2025
• ICS: 19.040 - Environmental testing
• Technical Committee: I09 - Imaginarni 09
• Current Stage: 5020 - Formal vote (FV) (Adopted Project)
• Start Date: 09-Jun-2026
• Due Date: 28-Jul-2026
• Completion Date: 10-Jun-2026
• Ref Project: EN IEC 60721-3-3:2019/A1:2026 - Classification of environmental conditions - Part 3-3: Classification of groups of environmental parameters and their severities - Stationary use at weatherprotected locations

• Amends: SIST EN IEC 60721-3-3:2019 - 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)
• Effective Date: 11-Jun-2024

SIST EN IEC 60721-3-3:2019/kFprA1:2026 is a CLC amendment to the classification of environmental conditions for stationary use at weatherprotected locations. It updates the way the standard classifies chemically active substances and mechanical conditions, so users can describe the site atmosphere, vibration and shock level in a common technical language.

What does SIST EN IEC 60721-3-3:2019/kFprA1:2026 specify?

SIST EN IEC 60721-3-3:2019/kFprA1:2026 updates Part 3-3 of IEC 60721 for stationary installations at weatherprotected locations. The amendment is centered on clause 5 and adds an informative annex for atmospheric contaminants.

The document is organized around:

• updated subclause 5.5 on chemically active substances
• updated subclause 5.7 on mechanical conditions
• a revised Table 5 and Figures 1 to 3 for vibration and shock
• new informative Annex C for classification of chemically active substances

Annex	What it covers
Annex B	Definition of the seismic environment
Annex C	Classification of chemically active substances

What are the key requirements of SIST EN IEC 60721-3-3:2019/kFprA1:2026?

Chemically active substances (C)

Clause 5.5 says that chemical contamination of the atmosphere mainly comes from industrial emissions, motor-driven vehicles and heating systems, with sea salt and road salt aerosols also contributing. In practice, the user needs to think about the local air chemistry because it can affect both function and materials.

Clause 5.5 allows the classification to be based either on ISO 9223 or on the classification in Annex C. That matters because the choice is application-dependent - the same site can be described with a different classification method depending on what the user needs to specify.

Annex C introduces the classes 3C1R, 3C1L, 3C1, 3C2, 3C3 and 3C4, and Table C.1 gives the contaminant levels behind them. For users, this means the document supports both broad location categories and a more detailed contaminant-by-contaminant description.

Annex C also distinguishes maximum values from mean values. In practice, maximum values describe short peaks, while mean values describe long-term exposure, so both the short-term and long-term effect on materials can be considered.

Mechanical conditions (M)

Clause 5.7 treats mechanical conditions as vibration and shock at the location, for example from normal operations or nearby vehicular movement. This is the basis for matching the site environment to the right severity class before design or qualification work starts.

The updated Table 5 classifies stationary vibration, sinusoidal; stationary vibration, random; and non-stationary vibration including shock. That matters because different equipment and different vibration sources are described in different ways.

The mechanical classes run from 3M10 to 3M14, moving from insignificant to extremely high vibration and shock. In practical terms, a user selects the class that best matches the actual installation, such as a location near air conditioning, machinery, conveyor belts or heavy machinery.

Figures 1 to 3 give the graphical forms of these mechanical conditions, and Annex B is referenced for the seismic environment. That helps users separate ordinary vibration and shock from earthquake-related conditions when they specify or test the environment.

What terms does SIST EN IEC 60721-3-3:2019/kFprA1:2026 define?

• Chemically active substances (C) - atmospheric contaminants that can affect product function and materials.
• Mechanical conditions (M) - the vibration and shock levels present at the location.
• 3C1R - a location with a stringently monitored and controlled atmosphere, identified as a clean room category.
• 3C1L - a location with a continuously controlled atmosphere.
• 3C2 - a location in an urban area with industrial activities or heavy traffic.
• 3M12 - a location with moderate vibration and shock, such as near machinery and conveyor belts.
• Non-stationary vibration including shock - a mechanical condition that can occur together with stationary vibration and is represented by shock response spectrum curves.

Who uses SIST EN IEC 60721-3-3:2019/kFprA1:2026?

SIST EN IEC 60721-3-3:2019/kFprA1:2026 is used by engineers, quality managers, buyers and test laboratories that need to describe the environment for a stationary installation at a weatherprotected location. It is also useful in procurement, design verification and environmental qualification, where the site conditions have to be translated into a clear severity class.

What changed in SIST EN IEC 60721-3-3:2019/kFprA1:2026 from the previous edition?

SIST EN IEC 60721-3-3:2019/kFprA1:2026 amends IEC 60721-3-3:2019 by:

• replacing subclause 5.5 with updated text on chemically active substances
• replacing subclause 5.7 with updated text on mechanical conditions
• deleting the existing Table 5 and all figures, and replacing them with a new Table 5 and Figures 1 to 3
• adding informative Annex C for the classification of chemically active substances

Which standards are used with SIST EN IEC 60721-3-3:2019/kFprA1:2026?

• ISO 9223 - named as one of the two ways to classify chemically active substances; it provides an alternative basis for the environmental classification of atmospheric corrosion conditions.

What does the SIST EN IEC 60721-3-3:2019/kFprA1:2026 document contain?

SIST EN IEC 60721-3-3:2019/kFprA1:2026 contains revised descriptive text for chemical and mechanical environmental conditions, together with a new classification table and figures for vibration and shock. Annex C adds Table C.1 and explanatory notes on how to apply maximum values, mean values and the 3C1R to 3C4 classes. The document is used when selecting environmental severities for design, testing, qualification and site specification.

SLOVENSKI STANDARD
SIST EN IEC 60721-3-3:2019/oprA1:2025
01-maj-2025
Klasifikacija okoljskih pogojev - 3-3. del: Klasifikacija skupin okoljskih parametrov
in njihove resnosti - Stacionarna uporaba na lokacijah, zaščitenih pred
vremenskimi vplivi - Dopolnilo A1
Amendment 1 - 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
Ta slovenski standard je istoveten z: EN IEC 60721-3-3:2019/prA1:2025
ICS:
19.040 Preskušanje v zvezi z Environmental testing
okoljem
SIST EN IEC 60721-3-3:2019/oprA1:2025 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

SIST EN IEC 60721-3-3:2019/oprA1:2025

SIST EN IEC 60721-3-3:2019/oprA1:2025
104/1091/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60721-3-3/AMD1 ED3
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2025-02-28 2025-05-23
SUPERSEDES DOCUMENTS:
104/1064/CD, 104/1083/CC
IEC TC 104 : ENVIRONMENTAL CONDITIONS, CLASSIFICATION AND METHODS OF TEST
SECRETARIAT: SECRETARY:
Sweden Mr Joakim Grafström
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):
TC 9,SC 17C,TC 22,SC 22G,SC 23J,SC 37B,TC 38,TC
44,SC 48D,TC 57,TC 82,TC 85,SC 86A,TC 94,TC 95,TC
97,TC 105
ASPECTS CONCERNED:
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft for
Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of which they
are aware and to provide supporting documentation.
Recipients of this document are invited to submit, with their comments, notification of any relevant “In Some Countries”
clauses to be included should this proposal proceed. Recipients are reminded that the CDV stage is the final stage for
submitting ISC clauses. (SEE AC/22/2007 OR NEW GUIDANCE DOC).

TITLE:
Amendment 1 - Classification of environmental conditions - Part 3-3: Classification of groups of
environmental parameters and their severities - Stationary use at weatherprotected locations

PROPOSED STABILITY DATE: 2029
NOTE FROM TC/SC OFFICERS:
electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
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SIST EN IEC 60721-3-3:2019/oprA1:2025
IEC CDV 60721-3-3 A1 © IEC 2025 2 104/1091/CDV
1 Proposed Amendment of IEC 60721-3-3:2019 Classification of environmental conditions - Part
2 3-3: Classification of groups of environmental parameters and their severities - Stationary use
3 at weatherprotected locations
4 Replace the existing sub clause 5.5 with the following text;
5 5.5 Chemically active substances (C)
6 The contamination of the natural atmosphere is mainly caused by chemical emissions from industrial
7 activities, motor-driven vehicles, and heating systems. A further chemical influence is caused by
8 aerosols of sea and road salts. Contamination may affect the function and materials of products.
9 A categorization of these substances and their allowed concentrations may either be based on
10 ISO 9223 or on the classification found in Annex C. Both categorizations have a different approach
11 and application background. Depending on the application background, the appropriate categorization
12 has to be selected.
14 Replace the existing sub clause 5.7 with the following text;
15 5.7 Mechanical conditions (M)
16 Mechanical conditions relate to the levels of vibration and shock that may exist at the location, for
17 example as a result of normal operations, nearby vehicular movement. These conditions are specified
18 in Table 5 and Figures 1, 2 and 3. See Annex B for the definition of seismic environment.
19 – 3M10 applies to locations experiencing insignificant levels of vibration and shock.
20 – 3M11 applies to locations experiencing low levels of vibration and insignificant levels of shock,
21 such as those transmitted from air conditioning, machines or passing vehicles in the vicinity.
22 – 3M12 applies to locations experiencing moderate levels of vibration and shock, such as those
23 close to machinery and conveyor belts.
24 – 3M13 applies to locations experiencing high levels of vibration and shock, such as those close to
25 or on heavy machinery.
26 – 3M14 applies to locations experiencing extremely high levels of vibration and shock, such as those
27 close to or on machinery such power hammers.
29 Delete the whole of table 5 and all figures and replace them with the following tables and figures;
SIST EN IEC 60721-3-3:2019/oprA1:2025
IEC CDV 60721-3-3 A1 © IEC 2025 3 104/1091/CDV
31 Table 5 − Classification of mechanical conditions
Class
Environmental parameter Unit
3M10 3M11 3M12 3M13 3M14
1)
a) Stationary vibration, sinusoidal:
Displacement amplitude mm 7 - 15 -
- 20 - 50
Acceleration amplitude No No No
m/s
Frequency range Hz 2 to 9 9 to 200 2 to 9 9 to 200
2)
b) Stationary vibration, random:
2 2
Acceleration power (m/s ) /
0,01 0,1 3 1 10 5
spectral density Hz
No
200 to 200 to
5 to 200 5 to 200 5 to 200
Frequency range Hz 5 to 200
2000 2000
3)
c) Non-stationary vibration including shock:
Shock Figure 3 Curve 1 Figure 3 Curve 2 Figure 3 Curve 2
(equivalent to a (equivalent to a (equivalent to a
half sine pulse half sine pulse of half sine pulse of
No No
2 2 2
of 20 m/s and 250 m/s and 6 ms 250 m/s and
11 ms duration) duration) 6 ms duration)
1)
Vibration generated by rotating
...