NEN 10721-3-6-1994
IEC 721-3-6-1987/+A1-1991 環境條件分類．第3部分：環境參數組及其嚴酷程度分類．第6節：船舶制造環境
Classification of environmental conditions.Part 3:Classification of groups of environmental parameters and their severities.Section 6:Ship environment(IEC 721-3-6:1987+A1:1991)