Tank to Pump

Nozzles & Equipment

Smooth-Bore Nozzle

A smooth-bore nozzle is a plain tapered tip that produces a solid stream and forms it at a lower tip pressure than a fog nozzle — about 50 psi on a handline. Its flow depends on the tip diameter and the pressure behind it.

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
50 psi
Flow at design
185 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.

SOLID STREAMA fixed orifice throws one solid, dense stream. It runs at a low design tip pressure, so it reaches far and is easier on the line — but you cannot change its pattern, and its flow is set by the tip size and pressure.

Nozzle type

A smooth-bore tip is a fixed, smooth orifice with no moving parts. It throws a single solid stream at a low design tip pressure; the tip diameter and pressure together set its flow.

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.

Compare 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 smooth bore throws a solid stream at a low pressure; the master stream throws the most water at a LOWER tip pressure than the fog — bigger means more flow, not more pressure.

With no moving parts, a smooth-bore tip simply lets water out through a fixed opening. The solid stream carries well, reaches far, and punches through to the seat of a fire, and because it forms at a lower pressure it asks less of the pump than a fog stream of similar flow.

Its flow is predictable from the tip size and the nozzle pressure, which makes it easy to plan for at the panel. Larger tips and higher pressures both raise the flow — and the nozzle reaction the crew has to hold.

Where this shows up

See also