Method for determining optimal parameters of approximating fire pump operating characteristic

Purpose. The article is devoted to studying the main operating characteristic of a fire pump (FP) – dependence of a fire truck (FT) fire pump pressure on its flow rate. When solving practical problems of pump-hose systems operation, as well as making up operational plans for fire extinguishment, analytical expressions with two constants are traditionally used which approximately describe the main operating characteristic of a FP with an error. At the same time, manufacturers of modern FP for FT provide empiric performance characteristics in technical documentation, which are approximated with a high degree of reliability by a second-degree polynomial with three constants. Analytical expressions obtained in this way are acceptable for engineering calculations, but are cumbersome when solving other fire-tactical problems. In this regard, the authors were to analyze the main operating characteristics of common FP models used in modern FT, and develop the most rational (with minimal deviations from performance characteristics of FP manufacturers) method of transition from an analytical expression to a traditional quadratic dependence. Methods. The research methods were systemic, structural, descriptive analysis and mathematical calculations based on scientifically verified and reliable data. Findings. There has been developed a new, previously unused method for transiting from performance characteristics of FP manufacturers for modern FT to traditional analytical expressions describing the main characteristic of a FP (pressure on flow rate dependence) with minimal error and in convenient for practical application form which allows significantly simplifying calculations for operating point of FT pump-hose systems. Research application field. The results of the study can be used to compile reference tables describing characteristics of FP various models used in modern FT to solve practical problems of optimizing pump-hose systems, and compiling operational plans for fire extinguishment. Conclusions. The proposed method allows significantly simplifying and speeding up calculations for determining the operating point of a FP when solving practical problems of pump and hose systems of FT in fire-fighting units.