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国家标准GB 31247-2014《电缆及光缆燃烧性能分级》已于2015年9月1日正式实施,该标准参照国际标准,将阻燃级别由原来的A、B、C、D级,改划分为A、B1、B2、B3级。A级为不燃型,也就是外护套为金属护套的电缆,如MI电缆等;B3为不阻燃型,如VV、YJV等;B1、B2级为应用量最大的阻燃电缆,应根据使用场所的重要性选择,一类高层民用建筑和人员密集场所应选择不低于B2级的阻燃电缆。该分级标准重新定义了阻燃级别,对电缆阻燃性提出了
National Standard GB 31247-2014 “Classification of Combustion Performance of Cables and Optical Cables” was put into effect on September 1, 2015. According to international standards, this standard classifies the flame retardant grades from original A, B, C, D grades into A, B1, B2, B3 level. Class A is non-combustible type, that is, the outer sheath is a metal sheathed cable, such as MI cable; B3 is non-flame retardant type, such as VV, YJV, etc .; B1, B2 level is the largest amount of flame- According to the choice of the importance of the place of use, a class of high-rise civil buildings and personnel-intensive places should choose not less than B2 grade flame retardant cable. This grading standard redefines the flame retardant level and presents the flame retardancy of the cable