Abstract: FK-5-1-12, known for its efficiency and cleanliness as a fire extinguishing agent, requires an effective release mode to fully utilize its capabilities. In order to assess the impact of different release modes on the performance of FK-5-1-12, a 20 mL n-heptane oil pan fire was used as a model for class B flames. The research utilized 1.2 MPa N2 filling and 2 g of nitrogen-rich gas-producing substances (NGS) to facilitate the release of FK-5-1-12. The research focused on comparing and analyzing the fire extinguishing effectiveness, cooling capacity, and mechanisms of FK-5-1-12 on class B flames under these two release modes. The research revealed that application pressure had a significant impact on the fire extinguishing effectiveness of FK-5-1-12. When released through the high-pressure gas flow generated by NGS, FK-5-1-12 showed better performance in extinguishing time, cooling effect, and flame suppression compared to the N2 drive release mode. Mechanistic analysis indicated that a substantial amount of FK-5-1-12 in the 1.2 MPa N2 drive did not reach the flame surface due to volatilization during release. In contrast, FK-5-1-12 effectively reached the burning surface of the flame with the influence of the high-pressure gas flow produced by only 2 g of NGS. Upon reaching the flame, FK-5-1-12 decomposed by absorbing heat, exerted a chemical inhibition effect, and rapidly halted the combustion reaction.

Key words: FK-5-1-12, release mode, class B flame, extinguishing performance