The article substantiates the need to clarify the value of pressure losses in the shut-off valves. Various methods of determining the coefficient of local resistance of steel ball valves are considered. A comparative analysis of the values of the local resistance coefficient obtained theoretically and experimentally is performed. Recommendations on the application of numerical values of the local resistance coefficient of steel ball valves are given.

Keywords: hydraulic calculation, pressure loss, disconnecting devices, ball valve, local resistance coefficient