Development of Gas Generators for Fire Extinguishing

Abstract

AbstractGas producing materials are widely used in military or space applications as solid rocket and gun propellants. The chemical formulations of these propellants cannot be directly transferred to other applications as their product gases are optimized on high power, producing high amounts of CO and toxic trace constituents not acceptable in industrial applications.Beneath small scale applications in inflating bag boats or ejecting pilots of aircrafts etc. the gas generators for airbag inflation became a standard equipment of cars and improved safety of drivers and passengers substantially.Recently, systematic investigations started to realize the idea of using gases or aerosols produced by solid energetic or pyrotechnique materials for fire extinguishing. The actually introduced chemical gas generator formulations are based on the experience of pyrotechnics and solid propellants. Sodium azide and nitrocellulose containing mixtures cover most requirements on mass products. Despite their high level of technical development both formulations exhibit strong disadvantages.The work reported considers organic formulations for fire extinguishing, which produce gases composed of N2 and CO2. The gasgenerants described consist of non‐toxic chemicals including fuel, oxidant, catalyst and cooling agent for thermal process control. The formulations show higher gas output per mass, can be recycled environmentally friendly and are of low costs. The results comprise thermochemical properties governing the time dependent gas output, characterization of the constituents and trace species of the product gas, safety and stability aspects. From selected gas generants the following data were measured: Estimation of thermal stability using DSC methods and mass‐loss tests; Pressure/time curves in the ballistic bomb; Rate of product gases by means of gaschromatography.