美利体育登录入口官网:JIS C 60721-3-4:1997 环境条件分类.第3部分:环境参数组及其严酷程度分类.第4节:在无气候防护场所的固定使用
Classification of environmental conditions Part 3: Classification of groups of environmental parameters and their severities Section 4: Stationary use at non-weatherprotected locations