Evaluation of small scale n‐heptane fire extinguishing efficacy by natural antioxidants based pyrotechnic compositions: An experimental study

Abstract

SummaryThe conventional pyrotechnic compositions (PCs) for firefighting application mostly consist of potassium nitrate, chlorate or perchlorate as oxidants and organic resin‐like phenol‐formaldehyde, melamine‐formaldehyde, epoxy resin and polyurethanes are used as reducers. Unfortunately, there are also some potential disadvantages to the use of conventional compositions. These are related to high combustion temperature with the generation of heat and flame which may cause secondary fire chances and hazards associated with the use of organic resins. Exposure to phenol, melamine, epoxy resins and polyurethanes are considered as a life‐threatening occupational hazard. Under the present study, new pyrotechnic compositions were prepared with the combination of natural antioxidants like ascorbic acid and gallic acid as reductant and mixture of potassium nitrate with potassium chlorate as oxidant. Fire extinguishing efficacies, calorific value, burn rate, the flame temperature of newly developed compositions was evaluated against potassium nitrate and phenol‐formaldehyde resin‐based conventional composition. Although both the new and conventional composition has shown good fire extinguishing efficacies, extinguishing 4.57 KW of small scale n‐heptane pool fire in 3 to 4 seconds, these newly developed compositions showed 67% to 76% reduction in flame temperature. It was also found that these new compositions exhibit a faster burn rate and lower calorific value than the conventional composition. To understand the fire extinguishing mechanism by the discharged aerosol particulate, its physical and chemical characteristics were assessed by a series of techniques viz; HRXRD, SEM, FTIR, EDX.