Abstract: Aiming at the practical problems existing in individual respiratory protection equipment for firefighters during forest fire extinguishing and rescue operations, such as high breathing resistance, limited service duration and insufficient comfort, this study developed a new type of air-supply respiratory protection equipment for firefighters in forest fire fighting based on the structural principle of powered air-purifying respirators. By analyzing the special respiratory protection requirements for forest fire suppression, combined with relevant studies on the actual carrying mode, air supply system and adaptive functions of respirators, the respiratory protection equipment with dual-canister smoke filtration and dual-hose air supply structure was developed by comprehensively adopting CFD simulation, theoretical calculation and experimental testing, and integrating devices including ambient air bypass and fire-resistant exhalation valve. The results show that the dual-hose air supply structure equipped with dual-canister smoke filtration is superior to the single-hose air supply structure with single-canister smoke filtration in performance indicators such as static pressure, flow velocity, dynamic pressure and breathing resistance. Especially in the air hose section, the average flow velocity and dynamic pressure of the dual-hose structure are reduced by 63.1% and 86.4% respectively compared with the single-hose mode, and the service duration is increased by 46.1%.

Key words: forest fire fighting, respiratory protection, powered air-supply respirator, ambient air bypass, fire-resistant exhalation valve