Ch 6 Hose Nozzles and Flow Rates

Question 1

Solid Steam Nozzle

Answer 1

-Produced with a fixed orifice and a smooth bore nozzle
-Stream is tight with little spray or shower
-Flow determined by size of discharge orifice and nozzle pressure
-Cannot change GPM’s flowing without effecting stream
-Master streams nozzles have “stacked tips” usually 1
-Freeman Experiments created what’s known as “standard tip”½ ,1 3/8th, 1 ¼, 1”
-Handlines operate at 50 psi
-Master streams operate 80 psi
Flow of solid stream GPM= 29.7×D²x√NP
GPM= discharge in gallons per minute
29.7= constant
D= diameter of orifice
NP= nozzle pressure
Example determine flow 1in tip operating 50 psi
GPM= (29.7) (1)² (√50)
GPM= 210.01

Question 2

GPM of Smooth Bore Nozzle Formula

Answer 2

GPM= 29.7×D² x √NP
- Example: determine flow 1in tip operating 50 psi
GPM= (29.7) (1)² (√50)
GPM= 210.01

Question 3

Find the GPMs of a 2” hose with a 1 1/8” tip flowing at 50 psi

Answer 3

GPM= 29.7×D² x √NP
GPM= (29.7) (1.125)² (√50)
GPM= (37.59) (√50)
GPM= 265.8

Question 4

Fog Stream Nozzle

Answer 4

• In order for stream to be broken into fine particles it must be driven against an obstruction with sufficient force to diffuse the water and shatter mass
• Wide deflection produces wide angle
• Narrow deflection produces narrow angle
• The reach is related to its width, wind, volume of water
• Impinging stream breaks water into fine evenly divided particles
  -Provide a wide-angle fog
• Narrow fog 15-45 degree
• Wide fog 45-80 degree
• Constant flow nozzle- Flow a specific volume of water on all stream patterns
  -Periphery-deflected stream deflect water inside a circular stem in nozzle
  -Some equipped with adjustable nozzle (different GPM settings)
  -usually operate 100psi (some 50 or 75 psi)
• Selectable gallonage nozzle
  -Allow firefighter to select the flow rate
  -usually operates 100psi
• Automatic fog nozzle
  -Type of variable flow nozzle with ability to change patterns while maintaining nozzle pressure
  -Made by spring-activated device in nozzle that constricts or expands the space between the baffle and the interior throat of nozzle
  -If gallonage changes will maintain same pressure
  -most operate 100psi (some 50 or 75)
• High pressure fog nozzle
  -Operate pressure up to 800psi (low flow rate 8-15gpm) wildland fire
  -* Advantages= dissipate more heat due to surface to air ratio, multiple patterns, ventilation capable, water curtain for radiant heat, class A/B foam, typically not conduct electricity
• Disadvantages= reach/penetration, susceptible to wind, steaming, increase fire spread*

Question 5

Master Stream

Answer 5

• Generate considerable nozzle reaction due to flow rate
  -* Water flow over 350gpm
• Most common: 500-1000gpm*
• Incidents where handlines are inefficient or personnel limited
• 80psi on smooth bore 100psi fog
• Used from fix position master stream appliances generally change direction of water to reduce nozzle reaction
• Ability to change stream and direction while water is being discharged
  -Fixed Monitors (Deck guns) permanently mounted to truck
  -Combination May be used on truck or removed to location
  -Has flow limitations when removed from apparatus
  -Portable Stored on apparatus for deployment

Question 6

Special Purpose Nozzles

Answer 6

• Cellar nozzle- Lowered through holes or openings to cellar
  -May be deployed in attic or other voids
  -Referred as distributors
• Piercing nozzle- Penetrating nozzle for aircraft or car fires
  -Hardened steel point capable of being driven through variety of material
  -3-6-foot steel rod 1 ½ inches diameter 125 gpm 100psi
• Chimney nozzle Suppress fire in chimney flows 1.5 to 3 gpm
  -Solid brass or steel with impinging holes to produce a mist

Question 7

What is Nozzle Reaction?

Answer 7

Counterforce against person holding nozzle by the velocity of water being discharged

Question 8

Nozzle Reaction for Solid Stream Formula

Answer 8

NR=1.57xD² xNP
- Example: 1 ¼ inch tip 50 psi
NR= (1.57) (1.25)2 (50)
NR= 122.66lb

Question 9

Simple guideline for approximate Nozzle Reaction of Solid Stream

Answer 9

NR= Q/3

Q= GPM

Question 10

What is the Nozzle Reaction of a 1 1/8” smooth bore tip operating at 50 psi?

Answer 10

NR= 1.57xD² xNP
NR= (1.57)(1.125)²(50)
NR= 99.35lbs

Question 11

Nozzle Reaction for Fog Nozzle Formula

Answer 11

NR=0.0505xQx√NP
200gpm at 100psi
NR= (0.0505) (200) (√100)
NR= 101lb

Question 12

Simple guideline for approximate Nozzle Reaction of fog nozzle

Answer 12

NR=Q/2

Question 13

What is the Nozzle Reaction of a fog nozzle flowing 150 gpm @ 50psi?

Answer 13

NR=0.0505xQx√NP
NR= (0.0505)(150)(√50)
NR= 53.56lbs

Question 14

which produces more nozzle reaction, fog or smoothbore

Answer 14

smoothbore