IEC 60721-3-9 Ed. 2.0 b:2024 PDF

This part of IEC 60721 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.

Characteristic parameters for the microclimates are high air temperature and high relative air humidity. Further parameters of the climatic classes, for example low temperature, can affect the components additionally, but have not been considered here.

A limited number of microclimatic classes is specified taking into consideration typical limiting high air temperatures of components.

NOTE The term "microclimate" can, for example in meteorology or buildings, have a different meaning than those discussed in this document.

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

IEC 60721-3-0:2020, Classification of environmental conditions – Part 3-0: Classification of groups of environmental parameters and their severities – Introduction

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 60721-3-4:2019, Classification of environmental conditions – Part 3-4: Classification of groups of environmental parameters and their severities – Stationary use at nonweatherprotected locations