FireOps CalcPDP = FL + NP ± Elevation + Appliance Loss
NP changes with nozzle type and manufacturer data
Step-by-step process
Identify the nozzleDo not assume all nozzles are the same.
Find target flowKnow the desired GPM for that nozzle package.
Use the correct nozzle pressureUse department specs or manufacturer data.
Calculate hose friction lossUse hose size, length, and C-value.
Add everything togetherFriction loss plus nozzle pressure gives the base PDP before elevation or appliance loss.
Worked example
Same hose200 ft of 1¾ inch
Same flow185 GPM
Lower nozzle pressure exampleLower PDP
Higher nozzle pressure exampleHigher PDP
TakeawayNozzle package matters
FireOps Calc should label nozzles clearly, for example “Fog 185 @ 50 PSI” or “Smooth Bore 15/16 @ 50 PSI,” so users do not confuse flow with pressure.
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
Is one nozzle always better?
No. Nozzle choice depends on department tactics, staffing, training, hose package, and flow goals.
Why should the app show nozzle pressure in the name?
Because two nozzles can flow similar GPM but require different pressures. Clear labels prevent bad pump calculations.