Abstract: Abstract: Gas fire extinguishing systems are often used in data rooms, battery energy storage cabins and other important places where water is not suitable for fire extinguishing. The airtightness of the protective area of the gas fire extinguishing system directly affects the success rate of fire extinguishing. In recent years, the problem of air tightness in the protective area has led to insufficient hold time, resulting in cases of fire reignition. However, the specific method of gas tightness test in the protective area of gas fire extinguishing system has not been specified in the current domestic gas engineering construction standards, which has caused an obvious lack of fire supervision. In order to ensure the reliability of the gas extinguishing system, it is urgent to test and verify the gas tightness of the gas extinguishing system protection area. This paper summarized the test methods for verifying the reliability of the protective area of the gas fire extinguishing system, comparing and analyzing the differences in the calculation models in the commonly used foreign gas tightness detection standards, and finds out through the design test that the actual concentration distribution of the air-agent interface is in the interval between NFPA 2001 and ISO 14520-1 hypothesis model, Which verified the blower door method to test the hold time.The feasibility analysis of the calculation method of peak pressure for fire extinguishing system protection is made, which provided a scientific reference for the future improvement of the gas tightness test method of the gas fire extinguishing system protection area in China.

Key words: gas fire extinguishing systems, enclosure, enclosure integrity test, hold time, peak pressure