You must use a respirator if the fuel-gas concentration in the work area is 5% more than the lower explosive limit (LEL).
如果工作区域的油气浓度比最低爆炸浓度高出5%，必须使用呼吸器。
The paper experimentally studied the explosive limit and the critical oxygen concentration of several kinds of gases that are found in the mine.
通过实验，对煤矿井下存在的多元混合气体的爆炸极限和临界氧浓度进行了分析和研究。
The explosive limits of concentration, explosive morphology, explosive waveforms and their influence factors were investigated.
探索了浓度爆炸极限、爆炸形态与波形及其影响因素；
应用推荐