Abstract: Foam extinguishing agents are one of the effective methods for combating oil fires; however, there are numerous types with significant variations in their compositions, and the compatibility issues among different types of foam extinguishing agents need to be explored. This study selected three typical low-expansion foam extinguishing agents: aqueous film-forming foam (AFFF), fluoroprotein foam (FP), and synthetic foam (S). These were mixed in five different ratios in pairs, and physical-chemical and extinguishing experiments were conducted to systematically analyze the effects of the mixing types and ratios on drainage time, coarsening rate, spreading process, and extinguishing time. The results indicate that adding a small amount of FP to AFFF can enhance its foam stability to some extent, as evidenced by slower drainage and coarsening rates, while AFFF/S and FP/S mixed foams showed poorer stability. Furthermore, due to the enhanced stability, the AFFF/FP mixed foam exhibited better extinguishing performance at a mixing ratio of 3：1. The FP/S mixed foam, due to its lower stability, required the longest time for extinguishing, indicating poorer performance. Therefore, AFFF and FP demonstrate a certain degree of compatibility and can be mixed in specific ratios under certain conditions.

Key words: foam extinguishing agent, drainage, coarsening, extinguishing time