Abstract: This article discusses the application of 50 mm fire hoses in building fire fighting. Through calculations, comparisons, and measurements, the performance parameters of 50 mm and 65 mm hoses are compared. The advantages of using 50 mm hoses in terms of the number of personnel, fire water supply, fire extinguishing load, ease of operation, hose loss, and personnel safety are studied. Meanwhile, the weaknesses of 50 mm hoses in terms of impedance coefficient, water supply intensity, and vertical laying are analyzed. The conclusion points out that firefighting and rescue teams should use and popularize 50 mm hoses as the main branch hoses in extinguishing building fires to optimize firefighting and rescue operations and ensure safety.

Key words: fire host, 50 mm host, building fire, fire extinguishing application, wall fire hydrant host