Tank to Pump

Nozzles & Equipment

Fog Nozzle

A fog nozzle breaks water into a cone of droplets and is built around a higher tip pressure than a smooth bore — a standard fog wants about 100 psi. The droplet pattern gives reach, absorbs heat, and can be adjusted from straight stream to wide fog.

A side-mount of four firefighting nozzle constructions fed by one hose: a smooth-bore tip throwing a single solid stream at a low design tip pressure, a fog combination tip shaping a widening cone of broken-up water at a higher pressure, an automatic fog tip with an internal baffle and spring that keeps the flow up near rated across a band of delivered pressures while the tip pressure tracks the supply, and a master-stream monitor throwing a large solid stream at a moderate design tip pressure. A per-type readout contrasts each tip's design pressure against its engine-derived flow, showing the master flows the most water at a lower pressure than the fog.

Nozzle types · interactive

Design tip pressure
100 psi
Flow at design
150 gpm
  • Smooth bore50 psi · 185 gpm
  • Fog / combination100 psi · 150 gpm
  • Automatic100 psi · 150 gpm
  • Master stream80 psi · 500 gpm
  • The master flows the most water at a lower tip pressure than the fog — bigger means more flow, not more pressure.

FOG CONEA combination tip shapes an adjustable cone — straight stream to wide fog. It needs a higher design tip pressure to break up the water, and it flows its fixed rating at that pressure.

Nozzle type

A fog (combination) nozzle has movable parts that shape the water into an adjustable cone. Breaking the stream up takes a higher design tip pressure than a smooth bore, and at that pressure it flows its fixed rating.

All three are valid, effective tips — the point is the contrast, not a ranking. These are training estimates; the stream shapes are illustrative. Follow your SOPs and your nozzle's own rating and operating range.

Step through the tips — smooth bore, fog, automatic, and master stream — and watch the cutaway, the stream pattern, the design tip pressure, and the flow change. The master stream moves the most water at a LOWER tip pressure than the fog: bigger means more flow, not more pressure.

By dividing the stream into droplets, a fog nozzle exposes far more water surface to the fire, which makes it effective at absorbing heat and producing steam. Many also let the firefighter change the pattern on the fly.

That performance depends on getting the design pressure. Below it the cone collapses, reach suffers, and flow drops — an under-pumped fog line looks like water and behaves like a delay.

Where this shows up

See also