scope:

This section of IEC 721-3 classifies groups of environmental parameters and their severities to which products are subjected when mounted for stationary use at locations which are non-weatherprotected, including periods of erection work, downtime, maintenance and repair.

 Locations which are non-weatherprotected, where products may be mounted for stationary use permanently or temporarily,  include land-based and offshore locations. Use in and on vehicles is excepted.

The environmental conditions specified in this standard are limited to those which may directly affect the performance of products. 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 explosion hazards and conditions related to ionizing radiation are excluded. Any other unforeseen incidents are also excluded. The possiblity of their occurence should be taken into account in special cases.

Microclimate within a product is not included.

Conditions of stationary use at weatherprotectd locations, portable and non-stationary use, use in vehicles and ships, and conditions of storage and transportation are given in other sections of IEC 721-3.

A limited number of classes of environmental conditions is given, covering a broad field of application. The user of this standard should select the lowest classification necessary for covering the conditions of the intended use. Some guidance of this is given in annex A.