HEAT OF COMBUSTION AND COMBUSTIBILITY COEFFICIENT: RELATIONSHIP BETWEEN FIRE HAZARD CHARACTERISTICS OF A SUBSTANCE

The article is devoted to the modernization of the classical coefficient of flammability (K), used to assess the fire hazard of substances. The authors establish the physical meaning of K, proving its proportionality to the heat of combustion. Based on stoichiometric and thermochemical analysis, a refined formula for calculating K is proposed, which includes previously ignored elements: phosphorus, silicon and boron. The coefficients for sulfur and hydrogen have been refined. Validation on a significant sample of substances showed a reduction in the calculation error to <7 % for the main classes of organic compounds (alkanes, alcohols, acids). For organic compounds containing silicon, boron the error does not exceed 9,1 %. The results make it possible to accurately assess the key parameters of fire danger: the lower concentration limit of flame propagation, the flash point, and the effectiveness of fire protection. The work is of high practical importance for the certification of materials and the development of fire-resistant composites.