Design method. Selection of the equation to calculate the pressure loss

The 2019.d version of CYPEFIRE Sprinklers allows users to select the pressure loss equation, either the “Hazen-Williams” or “Darcy-Weisbach” method, to apply when the sprinkler installation is analysed.

Upon selecting the pressure loss equation, other properties are defined, such as:

  • Specific gravity
    Ratio of the density of the fluid with respect to that of water at 4°C.

  • Relative viscosity
    Ratio of the kinematic viscosity of the fluid with respect to that of water at 20°C.

  • Precision
    Convergence criteria used to indicate that the solution to the non-linear equation has been found. The iterations end when the sum of all the changing flows divided by the sum of all the line flows is less than this number.

The Hazen-Williams analysis method is one of the most used methods due to its simplicity, but cannot be used for liquids other than water. The Darcy-Weisbach method, however, is more precise but more complex, because the friction factor has to be calculated. All these options can be edited and are located in the “General data” panel.