FireOps CalcPDP = FL + NP ± Elevation + Appliance Loss
FL per 100 ft = C × (GPM ÷ 100)²
Step-by-step process
Confirm the nozzle packageKnow the target GPM and nozzle pressure for your line.
Confirm the deployed lengthUse the actual or estimated hose length, not just the preconnect label if extra hose is added.
Calculate friction lossUse the selected hose C-value and GPM.
Add nozzle pressureAdd the nozzle pressure required for that nozzle package.
Communicate and adjustCharge the line, listen to the crew, and adjust within SOPs.
Worked example
Line200 ft of 1¾ inch
Flow185 GPM
C-value15.5
Nozzle pressure50 PSI
Calculated PDPabout 156 PSI
If the same 1¾ inch line uses a higher-pressure fog nozzle, the final PDP may be much higher. Build presets for your actual department nozzles.
Common mistakes to avoid
- Using a default nozzle pressure that does not match the actual nozzle.
- Forgetting extra hose, elevation, or appliance loss.
- Using textbook coefficients when your department has known hose data.
- Treating a training estimate as a replacement for department SOPs or instructor direction.
How FireOps Calc helps
FireOps Calc is built to make this process faster on a phone. Open the web calculator, enter your hose, nozzle, flow, elevation, and appliance values, then review the math breakdown instead of only seeing a final number.
FAQ
Why does my 1¾ line pump differently than another department?
Nozzle pressure, hose construction, hose age, actual length, and department flow targets can all change the result.
Can FireOps Calc save my department setup?
The app version is designed to save department-specific hose and nozzle presets so the calculator matches your rigs.