Fig. 1. The graphical abstract of current work. Display omitted •The exhaust flue pressure and air volume distribution were analyzed by full-scale tests.•The air leakage coefficient of the exhaust flue and the exhaust vent were established.•Two calculation methods for the applicable limit length of the ceiling centralized smoke exhaust system were established. Based on the Jiangxinzhou Yangtze River Tunnel, this study investigated the air leakage of a ceiling-centralized smoke exhaust system through full-scale tests and theoretical analysis. The theoretical analysis established a functional relationship between the pressure of the exhaust vent and air leakage volume. The air leakage coefficient of the exhaust vent was defined. The exhaust vent air leakage coefficient, exhaust flue area, hydraulic diameter, resistance coefficient along the exhaust flue, and exhaust vent spacing were integrated to establish the exhaust flue air leakage coefficient. Through full-scale tests, the exhaust flue pressure and air volume distribution were analyzed under different opening schemes of the exhaust vent. A section-by-section calculation method was established for the applicable limit length and air leakage of the ceiling centralized smoke exhaust system. This study further established a simple calculation method for the applicable limit length of a ceiling centralized smoke exhaust system through theoretical analysis, which made the calculation simple and easy to perform and enabled the results to be calculated with a certain degree of accuracy.