DIN 4753-7-1988
饮用水和服务性用水的热水器和水加热装置.采用抗腐蚀金属材料作触水面的防腐蚀处理.第7部分:要求和检验
Water heaters and water heating installations for drinking water and service water; corrosion protection on the water side by corrosion-resistant metallic materials; requirements and testing