The oxygen consumption principle test method is based on a simple physical fact that a certain amount of oxygen is consumed to generate a heat release amount.
For organic liquids and gaseous fuels with combustion products of CO2, H2O, HF, HCl, Br2, SO2 and N2, scholars believe that these bonds are similar because the energy generated during combustion is mainly caused by breaking CC bonds or CH bonds. The bond energy, therefore, although there is a large change in the molar heat of combustion for this type of fuel, the average heat of combustion per gram of oxygen consumed is 12.72 kJg with an error of within ±3%.
For natural fuels, such as wood, paper, cotton and other materials commonly used in construction, the average heat release per unit mass of oxygen is 13.21kJg, and the error is within ±5.3%. For incomplete combustion, the same conclusion is also reached.
For most natural organic materials and plastics, rubber and other materials, the consumption of 1m3 (standard state) oxygen will release about 1.7MJ of heat, or about 13.1×103kJ of heat per 1kg of oxygen, the measurement accuracy is less than 5%. . Therefore, by accurately measuring the flow rate and component concentration of the flue gas generated by the combustion of a substance, the heat release rate can be determined. This method is called the oxygen consumption principle calorimetry and is now widely used in building fire tests. in.
The main experimental SBI monomer combustion test (ie EN 13823SBI) of China's new grading standard is based on the principle of oxygen consumption. The burning performance test method of building materials mainly follows the following simplified assumptions: 1 The total amount of oxygen released per unit of mass consumed during complete combustion. The heat is constant, E = 13.1MJkg; 2 all gases are ideal gases; 3 the air flowing into the system includes O2, CO2, H2O and N2, and the gases flowing out of the system include O2, CO2, CO, H2O and N2, where N2 is Under the experimental conditions, it does not participate in the combustion reaction. All other inert gases that do not participate in the combustion reaction are treated as N2; 4O2, CO2 and CO are measured on a dry basis .