Abstract: Smoke exhaust at the fire scene is an important tactic for extinguishing building fires, which can create favorable conditions for firefighting and rescue. As a new smoke exhaust method, the straight-spray water gun has been applied at home and abroad, but there is a lack of systematic theoretical research, and it is urgent to carry out relevant tests to provide validation and support. This paper simulates the smoke exhaust effect under the same conditions by designing four test schemes of mobile positive pressure air supply smoke exhaust fan, natural smoke exhaust, straight-spray water gun positive pressure spray smoke exhaust and straight-spray water gun hydraulic ventilation smoke exhaust, and evaluates the smoke exhaust efficiency of each smoke exhaust mode by quantifying the attenuation degree of visible light penetration smoke. Experimental data shows that using a mobile positive pressure air supply smoke exhaust fan has the best smoke exhaust effect and the shortest time required; The effective smoke exhaust volume and efficiency of hydraulic ventilation with straight-spray water gun is the highest within the effective smoke exhaust time; The natural smoke exhaust efficiency is the lowest and takes the longest time.

Key words: straight-spray water gun, smoke exhaust at the fire scene, positive pressure ventilation, hydraulic ventilation