Chapter # 7 Fire Hose Nozzles and Flow Rates Flashcards
What environmental factors affect a fire stream?
Velocity. Gravity. Wind. Fiction with the Air.
What man made factors influence the condition of a fire stream?
Operating pressure. Nozzle design. Nozzle adjustment. Nozzle orifice condition.
The the three types of fire streams.
Broken, Fog, Solid.
A fire stream produced from a fixed orifice, smooth bore nozzle. Designed to provided a compact stream.
Solid stream
A solid stream nozzle gradually reduces its shape. The nozzle becomes a cylindrical bore who’s length is from one to one and half times its diameter. This design provides what?
A rounded shape to the water for better shape and reach.
What determines the flow and stream reach for a solid stream nozzle?
The nozzle pressure and size of the discharge opening.
Formula for flow from a solid stream nozzle.
GPM = 29.7 x d^2 x sq rt of NP GPM= gallons per minute. 29.7 = constant. d= diameter of orifice in inches. NP= nozzle pressure in psi.
Square root of 50?
7.07
The angle at which a stream of water is deflected from a obstruction determines the reduction in forward velocity of the stream, as well as the pattern or shape the stream assumes. So a wide angle deflection = ? and a narrow angle deflection = ?
Wide= Wide angle fog Narrow = Narrow angle fog.
The line bounding a rounded surface; the outward boundary of an object distinguished from its internal regions.
Periphery
A turning or state of being turned; a turning from a straight line or given course; a bending; a deviation.
Deflection
To strike or dash about or against; clashing with a sharp collision; to come together with force.
Impinge
A fog stream may be produced in these three ways.
A deflection at the periphery. By impinging jets of water. By a combination of these two.
Produced by deflecting water from the periphery of a inside circular stem of the nozzle. Then again deflected by the exterior barrel of the nozzle.
Periphery deflected streams.
The relative position of the deflecting stem and the exterior barrel determine what?
The shape of the fog stream.
Usually produce a wide angle fog pattern but can also make a narrow fog pattern.
Impinging stream fog nozzle.
Designed to flow a specific amount of water at a specific nozzle pressure on all stream patterns. Discharge the same volume of water no matter the pattern. Most flow at 100psi, some flow at 50 or 75 psi.
Constant Flow Nozzles
Has a number of constant flow rates which enables the firefighter to select the flow rate that best suites the fire conditions. Operated at 100 psi.
Automatic Nozzles
What is the minimum flow for interior structural fire fighting?
95-100 gpm.
Variable flow nozzle. Also called Constant Pressure nozzle or Multipurpose nozzles. Basically a variable flow nozzle with pattern change capabilities and the ability to maintain nozzle pressure and flow. Most operate at 100 psi, some at 50 or 75 psi.
Automatic fog nozzle
Can serve as a pressure regulator for a pumper as lines are shut down and added.
Automatic Nozzle
Will automatically vary its opening size (within range) to compensate for larger flows of water, to maintain a 100 psi at the tip.
Automatic Nozzle
Operate at pressures up to 800 psi. Fog stream with lots of forward velocity but very little water volume. Very fast moving , fine spray water. Best for wildland fires. Only flow 8-15 gpm.
High pressure fog nozzles.
Any fire stream that is to large to control without mechanical aid.
Master Stream
May be solid, fog, impinging, or broken stream nozzles. Flow 350 gpm or less.
Hand line nozzles
May be a solid or fog stream nozzle. Flows greater then 350 gpom.
Master Stream Nozzles
Smooth bore master stream tip psi? Fog nozzle master stream tip psi?
Smooth = 80 psi Fog = 100 psi
When are master streams used?
When handlines are ineffective, conditions unsafe, or manpower is limited.
What are the four basic categories of master stream devices?
Monitor. Turret Pipe. Deluge set. Elevated Master Stream.
Stream direction and angle can be change during water discharge. Three types; fixed, portable, combination. Fixed is also called a deck gun or turret.
Monitor
Mounted on the apparatus deck and connected directly to the pump by permanent piping. Also called deck gun or deck pipe.
Turret Pipe
A short length of large diameter hose with a large nozzle or playpipe supported at the end by a tripod. Siamese connection at the supply end. Angle and direction can not be changed during water flow.
Deluge Set
Large capacity nozzles designed to be placed on an aerial device. May be permanently attached or may be detachable.
Elevated Master Stream.
A master stream device used in conjunction with aerial ladders. Limited to vertical up and down motion. Horizontal movements put stress on the ladder. Attached to the rungs of a ladder and supplied with fire hose.
Ladder pipe
Have pre-plumed water ways instead of hose.
Some aerial ladders, all aerial platforms and elevated master streams.
The power system to operate a elevated master stream may be what?
Electric. Hydraulic. Pneumatic. Manual (non permit ones).
What special purpose nozzles are require to be carried according to NFPA 1901?
None
Created when water is forced through a series of small holes on the discharge end of the nozzle. Producing larger droplets of water when compared to fog streams. This gives them better reach and penetration.
Broken Stream Nozzle
Also called distributors. Often used on basement fires. May or may not be equipped with a shut off. Also used on attic fires. Nozzle is dropped through a cut opening of a floor or roof.
Cellar Nozzle
Can only absorb convected heat and not radiant heat.
Water Curtain Nozzle
Also called penetrating nozzles. Used in aircraft firefighting and to fight fire in accessible areas. May be used to deliver AFFF. 3-6’ by 1 1/2”. Usually delivers 100 gpm.
Piercing Nozzle
Designed to be placed on a booster hose. Solid piece of brass or steel with numerous very small impinging holes. At 100 psi = 1.5 - 3 psi. Very fine misty water cone. Lowered down then quickly pulled back out.
Chimney Nozzle
For every action there is a equal and opposite reaction.
Newtons third law of motion
What is the practical working limits for velocity of a fire stream? These velocities are produced from nozzles that have pressure ranges of …..to…. psi
60-120’ per second
25-100psi
Most solid stream handlines equipped with up to a 1 1/2” tip are flowed at what psi? What psi may they be increased to for greater reach with little detriment?
50 psi, 65 psi
Portable master streams should not be operated above the manufactures recommended psi. But, fixed master streams (not on aerial devices) can be operated between what range?
80-100 psi
What would be the most common reason for figuring out the nozzle reaction of a hose line?
When determining what hose lines / nozzles to have as preconnected lines on the apparatus.
Solid stream nozzle reaction equation.
NR = 1.57 x d^2 x NP
A fire ground method for approximating NR on a solid stream nozzle.
NR = Q/3 (Q is the total flow)
Fog stream nozzle reaction equation.
NR = 0.0505 x Q x sq rt of the NP. (Q is total flow. NOT flow /100).
Square root of 100.
10
A fir ground method for approximating NR of a fog nozzle.
NR = Q/2 (Q is the total flow)
