Analysis Of Halon Substitute Agent Environment Affection And Study On Extinguishing System Of Halon Substitutes

At the beginning of the 1980s, halon agent was considered to have destructive effect on the ozone layer, and it has threatened the environment. Therefore, measures were taken to phase out the halon fire extinguishing agent in many countries. 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. Among the halon alternatives, the clean agents permitted to be used in China mainly include trifluoro methane, heptafluoro propane, hexafluoride propane, IG541 etc. besides carbon dioxide. Theses agents have been recognized and recommended by International Standards Organization.The study on halon alternatives in China is in its initial stage. The study only has done some experiments on Heptafluoro propane, and the experiments still have some limitations. For example, the resistance loss, fire extinguishing concentrate, the flow status of the pipe network as well as the engineering evaluation etc. need to be improved. The application of the halon alternative fire extinguishing systems still faces with many problems. Based on the extensive research on the related materials at home and abroad, the thesis analyzes impact to envirment of halon agent,and analyzes and studies the physical and chemical performances and system components of halon alternatives.The fire suppression mechanism, advantages and disadvantages as well as the applicable places of different fire extinguishing agents have been given. Systematic environment evaluation has been done from the aspects of the effect of halon alternatives on the air, human being and equipment, storage stability as well as space occupancy rate; experiments have been done to verify the parameters such as the fire extinguishing time, discharge time, fire extinguishing concentration to obtain the flow coefficient and pressure as well as the discharge rate curve. They provided reliable data for the nozzle size determination of the system design. The flow status of the halon alternatives in the pipe network has been analyzed. It was found that heptafluoro propane is single phase (liquid), trifluoro methane and carbon dioxide is two phases (gas and liquid), IG541 is single phase (gas). The corresponding resistance loss equation has been established. Based on practice, the main reasons to the problems in the application of the halon alternative systems have been analyzed. The necessity and the main contents of studying the engineering application evaluation...