DIN EN 60721-3-4:1995 环境条件分类.第3部分:环境参数组分类及其严酷程度分级.第4节:在无天气防护位置固定使用的产品
Classification of environmental conditions - Part 3: Classification of groups of environmental parameters and their severities - Section 4: Stationary use at non-weatherprotected locations (IEC 60721-3-4:1995); German version EN 60721-3-4:1995