1. What is Pump Discharge Pressure?

Pump Discharge Pressure (PDP) is the pressure required at the fire pump to deliver adequate water flow through hose lines to the nozzle. It accounts for nozzle pressure, friction loss in hoses, and elevation differences.

2. How Does the Calculator Work?

The calculator uses the fire service pump pressure equation:

Where:

• \( PDP \) — Pump Discharge Pressure (psi)
• \( NP \) — Nozzle Pressure (50 psi standard)
• \( FL \) — Friction Loss (psi/100ft × length/100)
• \( ED \) — Elevation Difference (ft × 0.433 psi/ft)

Explanation: The equation calculates the total pressure needed to overcome nozzle requirements, hose friction, and elevation changes to deliver effective fire streams.

3. Importance of Pump Pressure Calculation

Details: Accurate pump pressure calculation is essential for effective firefighting operations. Proper pressure ensures adequate water flow for fire suppression while preventing equipment damage from over-pressurization.

4. Using the Calculator

Tips: Enter hose length in feet, friction loss per 100 feet in psi, and elevation difference in feet. Use positive elevation for uphill, negative for downhill. All values must be valid numerical inputs.

5. Frequently Asked Questions (FAQ)

Q1: What is standard nozzle pressure?
A: Most fire service nozzles operate at 50 psi, though some specialized nozzles may require different pressures.

Q2: How do I determine friction loss?
A: Friction loss depends on hose diameter, length, and flow rate. Consult fire service hydraulics charts for specific values.

Q3: Why is elevation important?
A: Each foot of elevation change requires 0.433 psi adjustment - uphill requires additional pressure, downhill requires less.

Q4: What are typical PDP ranges?
A: Most fireground operations require 100-200 psi, but this varies based on hose layout and fire conditions.

Q5: Should I add safety margins?
A: Many departments add 10-25 psi safety margin to calculated PDP to account for variables and ensure adequate flow.