IEC 60721-3-9:2024 classifies groups of microclimatic conditions, to which components (basic parts, assemblies, built-in units) can be subjected inside products, which are used under the climatic conditions as classified in IEC 60721-3-3 and IEC 60721-3-4.
This second edition cancels and replaces the first edition published in 1993, Amendment 1:1994 and Corrigendum 1:1995. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) Clause 2 has been updated;
b) Clause 4 has been re-edited and simplified;
c) Annex A has been revised and updated;
d) a new Annex B has been added and gives the origin of the constitutional diagram for humid air, which is the basis of drawing the climatogram for a microclimate.