IEC 60721-3-1:2018 is also available as IEC 60721-3-1:2018 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

IEC 60721-3-1:2018 classifies the groups of environmental parameters and their severities to which products together with their packaging, if any, are subjected when stored. The environmental conditions specified in this document are limited to those which can directly affect the products or their ultimate performance. Only environmental conditions as such are considered. No special description of the effects of these conditions on the products is given. Environmental conditions directly related to fire or explosions are not included. Conditions of stationary use, portable and non-stationary use, use in vehicles and ships, and conditions of transportation are given in other subparts of the IEC 60721-3 series. This third edition cancels and replaces the second edition, published in 1997, and constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a. Clause 3: reworded and simplified.
b. Clause 4: reworded and simplified.
c. Clause 5: Annex C has been incorporated in Clause 5.
d. 5.2: all existing climate classes have been replaced by completely new classes. The new classes are divided into 3 groups. The reason for the new classes is the latest revision of IEC 60721-2-1 which incorporated new climate types.
e. 5.3: new classes for solar radiation and snow load.
f. 5.6: all existing classes for mechanically active substances have been replaced by completely new classes.
g. 5.7: all existing classes for mechanical conditions have been replaced by completely new classes.
h. Table 1: new climatic classes with new severities.
i. Table 2: new classes for solar radiation and snow load.
j. Table 5 new mechanically active substances classes.
k. Table 6: new mechanical conditions classes.