IEC 60079-12-1978 Electrical apparatus for explosive gas atmospheres Part 12: Classification of mixtures of gases or vapours with air according to their maximum experimental safe yaps and minimum igniting currents
爆炸性气体环境用电气设备 第12部分:气体或蒸汽与空气的混合物按其最大实验安全间隙和最小引燃电流的分类