Chapter 10 Types of Fire Streams Flashcards
What are the four basic elements needed to produce a fire stream
- water source
- means to impart pressure
- means to transport water
- personnel trained in the first three elements
the four principal types of firehose appliances are:
wyes
siamese
water theifs
manifolds
small wyes used to break one medium diameter supply hose into two 1 3/4” or smaller attackers are known as ___?
leader line wyes
solid streams are classified as good if they have the following physical characteristics at point of breakover
- stream has not lost continuity by breaking up
- stream appears to shoot 90% of whole volume inside a circle 15” in diameter and 75% of it inside a 10” circle, by eye
- stream is stiff enough to attain the required height through moderate breeze
Given equal discharge pressures, when the diameter of the discharge opening of a solid stream smoothbore nozzle is doubled the flow capacity _____
quadruples
Most fire departments and training authorities advocate that the nozzle pressure on a handline solid stream nozzle not exceed____ … for master streams solid stream nozzles___
50 psi
80 psi
given equal discharge pressures the reach of the stream will increase as the diameter of the discharge orifice is____
increased
the solid streams maximum horizontal reach is at an angle of___ to the earth’s surface
32 degrees
what angle gives a solid stream the greatest vertical reach into structures
70-75 degrees
Handlines, typically if the nozzle tip’s diameter exceeds ___ of the diameter of the hose stream quality will be lowered
60%
what are the five advantages and four disadvantages of solid streams
advantages: 1. better visibility, 2. greater reach, 3. lower nozzle pressure 4. greater penetrating power, 5. less likely to disturb thermal layering
disadvantages: 1. one stream pattern 2. can’t use class B foam 3. less heat absorption, 4. conduct electricity
who are the four people who helped develop fog streams
Griswold, Layman, Royer , Nelson
what is the difference between velocity and speed
velocity is a rate of motion in a particular direction
speed is rated travel regardless of direction
fog stream selection must consider five factors
- gravity
- water velocity
- fire stream pattern
- water droplet friction with air
- wind
the two main reasons of fog stream will never be used from outside the structure
- reduced reached
2. inability to hit seat of the fire ( converted to steam)
type of fire fog streams are useful for fighting
enclosed fires
if the fog stream has a broken or otherwise unsatisfactory pattern likely culprit is
insufficient nozzle pressure
most standard fog nozzles are designed for optimal flow in streams operation at a discharge pressure of____
100psi
high-rise files fog nozzles may be as low 50 PSI
was a key factor in a fog streams of effectiveness in controlling fire
confined space with maximum conversion to steam
what are the disadvantages and advantages of fog streams
3/7
advantages: 1. dissipate heat by exposing maximum water surface for heat absorption 2. adjustable patterns 3. vary from straight stream to wide fog pattern 4. adjustable water usage 5. aid ventilation 6. nondestructive stream7. will not conduct electricity 7. class A and class B foam
disadvantages: 1. less reach and penetrating power than solid streams 2. more susceptible to wind 3. may contribute to fire spread
what is a broken stream?
stream will water that has been divided into core straps having characteristics of both a solid and fog stream. series of small solid streams that quickly break up
what are some differences between fog streams and broken streams
fog streams have a definite pattern broken streams do not
broken streams have larger drops of water and are generally not adjustable
broken streams conducted electricity
what are the disadvantages and advantages of broken strengths
advantages: 1. often the only means to applying water to fires and otherwise inaccessible spaces 2. have more heat absorbing capacity than solid streams
disadvantages: 1. may conduct electricity, no class C fires 2. method of water application may not be optimal, can produce more water damage than other streams 3. each broken stream nozzle typically has one application
