How is the total discharge pressure (DP) calculated in the example?

To calculate the total discharge pressure (DP), it is essential to understand how different components contribute to the overall pressure required for effective firefighting operations. In this context, each component represents a specific pressure contribution based on factors like friction loss (FL), elevation loss (EL), and the pressure needed to operate equipment such as a courtyard pack.

The correct calculation of DP involves summing the pressure contributions from friction loss, elevation gain, and operational pressure from equipment. In the provided scenario, the equation identifies 45 for friction loss, 10 for elevation loss, and 90 for the courtyard pack. This results in a total discharge pressure calculated as follows:

Total DP = Friction Loss + Elevation Loss + Equipment Pressure = 45 + 10 + 90

Understanding this process emphasizes the importance of considering all aspects of the system that affect discharge pressure, ensuring proper operation and efficiency during firefighting efforts. The other response options contain different numerical values that would lead to inaccurate assessments of DP, demonstrating that precise calculations are crucial in achieving the necessary operational effectiveness in firefighting scenarios.