NF C20-003-4*NF EN 60721-3-4:1995 环境条件分类 第3部分:环境参数及其恶劣程度的成组分类 第4节:无气候防护场所固定用
Classification of environmental conditions. Part 3 : classification of groups of environmental parameters and their severities. Section 4 : stationary use at non-weatherprotected locations.