Evaluating Class B Fire Extinguishing Efficacies of Organic Nitro Compounds Based Aerosol Forming Compositions

Abstract

Every year, increasing fire accidents worldwide have directed our attention towards an effective fire suppression system. For many decades, Halons have been used as effective fire extinguishing agents. Vienna convention (1985) and Montreal protocol (1987) determined Halons as ozone-depleting agents, and subsequently, their manufacturing is banned by the U.S. Environmental Protection Agency. Thus, against the urgent background of this elimination of Halons, aerosol-based extinguisher resulted as one of the significant Halons substitute technology. The Ozone Depletion Potential and Global Warming Potential values of aerosol extinguishing agents are nearly zero. This has provided thrust for various Universities and research institutions for undertaking numerous projects to develop aerosol-forming pyrotechnic composites for fire fighting applications. In the present work, novel fire extinguishing pyrotechnic compositions were fabricated, in which four different organic nitro compounds, 3,5-dinitrosalicylic acid, 3,5-dinitrobenzoic acid, m-nitrobenzenesulphonate and 3-nitrophthalic acid, were used as the reductant. These nitro compounds undergo rapid redox reaction with strong oxidants to produce aerosol fire extinguishing agents, extinguishing 4.57 KW of small scale n-heptane pool fires in 3 seconds. The fire extinguishing efficacy and thermal characteristics of novel compositions were evaluated against potassium nitrate and phenol formaldehyde resin-based conventional pyrotechnic composition.