Since the subscription of Montreal Protocol in 1987, the study on the halon alternatives ( clean gas fire extinguishing agent ) and the corresponding fire extinguishing systems has been lasted for more than 10 years. 从1987年蒙特利尔公约签署以来,关于哈龙替代物灭火剂(洁净气体灭火剂)和相应的灭火系统的研究已经历了10余年的时间。