Fire Streams and Nozzles Flashcards
1600’s
bucket brigade
1700’s
leather, copper riveted hose with playpipes
1800’s
2.5in cotton hose with underwriter’s playpipe
1940-1950
1.5in hose with assorted spray nozzles
1950-1960
combination of fixed nozzles and adjustable nozzles
1960-1970
added 1.75in hose and automatic nozzles
1970-1980
1.75 and 2.5in hoses with lots of automatic nozzles
1980-1990
Light weight hoses with dual pressure nozzles and special application attachments
Why do we use water to firefight?
a. Cheap, readily available, requires lots of specific heat and latent heat
Specific heat
The amount of energy required to increase the temperature of substance by one degree. One BTU is the amount of heat required to raise a pound of water one degree Fahrenheit at standard atmospheric pressure
Latent heat of vaporization
Energy required to change a substance from a liquid to a gas
Water expands ____ times its original volume when converted to steam
1700
d. Although energy is required to change forms, the water still stays ____throughout the process.
212F
You must apply enough water to …
absorb the heat faster than it is being generated
Fire stream
a stream of water or other extinguishing agent after it leaves the firehose and nozzle until it reaches the desired target
Water streams are ID’d by
size and type
Size =
volume, GPM
Type =
pattern
Sizes
i. Low flow =
Types
i. Fog
ii. Solid
iii. Broken
Solid stream
a solid stream is a fire stream produced from a fixed orifice, smooth bore nozzle
i. Reach and penetration
ii. A good solid stream places 90% of its water in a 15in circle, or 75% in a 10in circle at the break over point
Breakover point
the point where the stream loses its forward momentum and falls into showers of spray that can be blown away easily.
Advantages of solid stream
- Reach and penetration
- Not likely to disturb thermal layers as much
- Less nozzle reaction
- Easy to see
Disadvantages of solid stream
- Can’t change pattern
- Can’t be used for foam
- Less heat absorption per gallon
Fog stream
has a defined pattern and is composed of small droplets; adjustable
Advantages of fog stream
- Maximized heat absorption due to lots of water surface area
- Adjustable to situation
- Sometimes has adjustable gallonage
- Can aid in ventilation
Disadvantages of fog stream
- Less reach and penetrating power
- Susceptible to wind
- Can cause thermal inversion and steam burns
Broken Streams
no defined pattern
i. Created by device, bouncing streams off objects or other streams
ii. Large droplets have greater penetrating power
iii. Used in basement and ceiling fires
4 things needed for a good firestream
- Reliable water supply
- Fire pump
- Appropriate equipment – hoses, nozzles, etc
- Personnel trained to operate equipment
Limiting factors of firestreams
a. Velocity of water
b. Wind pattern and velocity
c. Stream pattern
d. Friction
e. Gravity
Horizontal reach is best achieved at what angel?
32 degrees
Vertical reach stats
a. Actual reach is best at 90 degrees (not super useful…)
b. Practical vertical reach is achieved at 70-75 degrees
c. Handline streams can be thrown to 3rd story
Nozzles!
Yay!
Types of nozzles
a. Smooth bore
b. Combo/fog
c. Special
Components of a nozzle
a. Shut off device
b. Stream shaping device
Hydraulic considerations
Friction loss
Nozzle pressure
elevation
Friction loss
the part of the total pressure that is lost while forcing the water through pipe, fittings, hose, etc
i. 1.75in loses 7psi per 50ft section
ii. 2.5in loses 5 psi per 50ft section
Nozzle pressure
there must be enough pressure for the nozzle to function properly and flow the correct amount of water
Elevation
i. Head pressure: the pressure resulting from the elevation of water
ii. .434psi/ft
iii. Generalize .5psi/ft or 5 psi per floor above ground level
Engine pressure stats
d. Engine pressure must be the desired nozzle pressure compensated for friction loss and elevation change
i. EP = NP + FL +/- Elevation
Nozzle reaction stats
the amount of force being generated at the nozzle opposite to the direction of the stream, measured in pounds.
a. Newton’s 3rd law
b. NR is created by velocity and flow: if NP ^, then NR ^
c. Fog patterns decrease nozzle reaction due to deflection
Nozzle reaction math smooth bore
Smooth bore: NR = 1.5 x D^2 x NP
For example: 1in solid stream, NP 50psi at 210GPM will generate 75lbs NR
Nozzle reaction math fog
Fog: NR = .05 x GPM x √NP
For example: a fog stream flowing at ~95gpm creates 48lbs NR
For example: fog, NP 100psi at 210GPM generates 105 NR
Nozzle functions
a. Control flow (GPM)
b. Provide reach
c. Shape stream
Standard operating pressure of nozzles
a. Smooth bore = 50psi
b. Combo = 100psi
c. Breakapart
i. Fog = 75psi
ii. Smooth bore = 50psi
d. Smooth bore master stream = 80 psi
e. Fog master stream = 100psi
Types of nozzles
Automatic Constant gallonage non-constant gallonage flushing fog nozzles smooth bore specialty
Automatic nozzles
iv. Maintain optimum nozzle pressure of 100psi
v. Increase in pressure leads to an increase of GPM
vi. Changing shape of stream does not affect GPM
vii. Have springs that keep the psi constant
viii. Can be throttled down if the flow is too great, but that might lead to an effective looking stream that really isn’t.
Task Force Tip
2.5in hose: 50-350GPM, 1.75in hose up to 225GPM
Akron Akromatic
2.5in hose: 60-375GPM, 1.75in up to 225GPM
Akron Akromatic Master Stream
up to 1250GPM
Constant gallonage
i. Give same GPM regardless of shape
ii. Has a selector ring that allows for change, but must inform engineer
v. Constant gallonage nozzles are also adjustable gallonage nozzles
KK Thunder Fogs
30-200GPM
Akron Turbojets
60-200GPM
Non-constant gallonage
i. GPM changes as you adjust the stream type
ii. The rated GPM is obtained at 30 degrees, increasing 15% when open to full fog and decreasing 15% when set to straight stream.
iii. Wildland hoses are an example
iv. Also called variable flow nozzles
Flushing fog nozzles
i. Allows for the removal of objects like stones, scale, etc up to 5/16in
ii. Some nozzles have a flush setting, rotate to flush
iii. Some nozzles have flush control on the front
Smooth bore nozzle stats
size on tips
i. Fixed orifice, thus single pattern
ii. Reach and penetration
iii. Nozzle tips should:
1. Not be bigger than 50% of the diameter of the hose
2. Linear portion of cylindrical bore of the tip should be 1x-1.5x the diameter of the tip orifice.
Smooth bore handline sizes
- 7/8”
- 1”
- 1 1/8”
- 1 ¼”
Smooth bore master stream sizes
- 1 ¼”
- 1 ½”
- 1 ¾”
- 2”
- 2 ¼”
Speciality nozzles
Flame fighter
break apart nozzle
Flame fighter nozzle pressure and size and GPM stats
PSI/NP GMP 1.75in 2.5in
100 190 250
125 215 274
150 n/a 320
Flame fighter nozzle
- Can go on either 1.75 or 2.5in line
- 2600ft2 of coverage
- Minimal nozzle reaction
- Used for confined spaces, cars/RV, compacted material
- 48in overall length but can be extended
- 1.5in NST pistol grip shut off butt
- 36in aluminum body with and addition 36in extension
- Hard plated chrome tip
Breakapart nozzle
- Can be used as smoothbore or fog
- Non-constant gallonage when used as fog
- 150GPM @ 75 psi Fog
- 180GPM @ 50 psi 15/16th smoothbore
Nozzle reminders
- No water hammer! Open/close nozzles slowly.
- Nozzles are tools upon which your life depends – treat them accordingly.
- Bleed air out of hose sooner rather than later.
