Abstract: Through experimental methods, obtain the actual performance of automatic sprinkler fire extinguishing systems under three simulated failure conditions, analyze and compare the expected fire extinguishing effectiveness under the system design conditions, and summarize the impact of different failure conditions on fire extinguishing effectiveness. The experimental results show：the sprinkler deflector failure will cause uneven water distribution and less effective control of early stage fire, so that the number of actuated sprinklers will increase to meet the fire control requirements, and the failure can result in about 40% reduction in fire extinguishing efficiency. The malfunction of the thermal sensitive element will lead to higher sprinkler operation temperature and longer response time, during which the fire develops too rapidly to be effectively controlled in the short term after the sprinkler actuation, and the malfunction can result in about 25% reduction in fire extinguishing efficiency. Furthermore insufficient working pressure will cause the most serious impact , which reduces the fire extinguishing efficiency by about 60%.

Key words: automatic sprinkler system, failure condition, protocol