Tank to Pump

Hydraulics & Pressure

Nozzle Pressure

NP

Nozzle pressure is the pressure of the water as it reaches the nozzle, and it sets both how much water flows and how good the stream looks. Each nozzle type is designed around a specific tip pressure.

A fire hose runs from a pump to a nozzle; the water stream forms fully at the nozzle's design tip pressure and collapses when under-pumped.

Nozzle pressure · interactive

GOODAt design pressure: a well-formed, effective stream at the nozzle's rated flow.

Nozzle type

Target band is the design pressure ±15% (the same window the panel uses to flag a line under- or over-pumped). Stream shape is illustrative; the pressures are training estimates — follow your SOPs and the nozzle's own data.

Each nozzle is built around a design tip pressure. Pick a nozzle and drag the actual tip pressure to see the stream — and the pump operator's verdict — change.

Different nozzles are built around different tip pressures: a smooth-bore handline forms a solid stream at about 50 psi, a standard fog nozzle wants about 100 psi, and a master-stream fog device runs around 80 psi. Pump pressure exists to deliver that tip pressure after the lay takes its cut.

Nozzle pressure is what the crew feels and what determines stream reach and droplet quality. Under-pump it and a fog cone collapses, reach falls off, and the line flows less than its rating — even though water is still coming out of the tip.

Common questions

What is nozzle pressure?
Nozzle pressure is the pressure of the water as it reaches the tip. It sets how much water flows and how the stream looks, and each nozzle type is designed around a specific tip pressure.
What nozzle pressure should I pump to?
As a training default, a smooth-bore handline forms a solid stream around 50 psi, a standard fog nozzle wants about 100 psi, and a master-stream device runs around 80 psi. These are learning estimates — pump to the figures in your department's SOPs and the nozzle's own data, not to a number from a training app.
Why does a stream look weak even though water is flowing?
Because the tip is below its design pressure. A fog cone needs its rated nozzle pressure to form properly; below it the cone collapses, reach drops, and the line moves less water than its rating even though the tip is clearly flowing.

Where this shows up

See also