Chp 6 Flashcards
Fire stream
Water forms after leaving the nozzle orifice
Influences on fire stream
Velocity Gravity Wind Friction with the air All affected by water droplet size
Three types of nozzles
Solid
Fog
Broken stream
Handline
Solid, fog or broken
3/4” to 3”
Generally 350 gpm max
Solid stream
Stream stays together as a sold mass.
Volume of water is gradually reduced until just before orifice
Note: SLC break aparts are just straight. Some don’t have enough length to straighten turbulent stream.
Also affected by type of valve (ball? gate)
Maximum reach and gpm for minimum NR
Solid stream flow
29.7 x D^2 x SQRT NP
Fog stream
Water stream of finely divided particles
Deflected at periphery around inside circular stem
or impinging jets of evenly divided water spraying at angles
SLCFD spins
Constant flow nozzles
Flow same volume of water at different steam patterns
Moves deflecting stem up and back inside but gap of that and interior throat stays the same
Most are 100 psi, some at 50
Selectable gallonage nozzle
Click to change gpm flowing
Most are 100 psi
Should say on the nozzle what the psi should be
Automatic fog nozzle
Reach and pressure stay the same as pdp changes, but gpm changes. Like putting your thumb on a hose
Based on spring so remember spring force must be overcome by pdp
Most are 100 psi
Master stream
Solid or fog
351 gpm and above
Lots of NR so need to be secured
Most have play pipe to reduce NR
Master stream applicances
Fixed: deck gun, permanently mounted
Combination: can have flow limitations if taken off
Portable: Stored on apparatus for deployment
Elevated master stream
Pre plumbed
Permanently attached
Detachable appliance
Remember recoil from NR when FF are on the tip
Cellar nozzle
aka distributors
Bresnan
We don’t cary play pipe needed to accurately deploy
Piercing nozzles
Angled, case-hardened steel tip and striking surface
Aircraft, care fire, voids, attics
Impinging jet nozzle at 125 gpm at 100 psi
We have Navy (sprinkler head) not these
