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Chapter 11 Nozzles and Fire Streams

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IntroductionFires usually extinguished by water

Water delivered using nozzles and fire streams

Nozzle selection important

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Definition of Fire StreamFire streamFour elements affect stream:

PumpWaterHoseNozzle

Proper streamSufficient volumePressureDirection to reach its target

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NozzlesNozzles:

Solid stream and fogCombination nozzles:

Straight stream or adjustable spray Nozzle pressureNozzle flowNozzle reachStream shapeNozzle reaction

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Nozzles showing the stream shape for straight, solid, and wide pattern

streams.

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Solid Tip or StreamDeliver unbroken stream of waterSolid stream nozzle Flow a factor of tip size at a certain

nozzle pressureMinimal effect of room’s thermal

balanceDisadvantages:

Lack of volume controlLack of fog protectionHigher nozzle reaction

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Fog Nozzles

Deliver fixed or variable spray pattern

Fog provides better heat absorptionHydraulic ventilation

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Variable combination fog nozzle patterns. From top to bottom: straight stream, narrow

fog, and wide fog.

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Parts of a fog nozzle.

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Straight StreamCreates a hollow type streamMust pass around the baffle of the

nozzleCreates an opening in the patternMay allow air into the stream and reduce

its reachNewer designs have hollow effect

from the tip.

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Comparison of (A) straight and (B) solid streams at tip.

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Special PurposeNot often usedCellar nozzles and Bresnan

distributorsPiercing nozzles

Modified to pierce through building walls and floors

Water curtain nozzleSprays water to protect against heat

exposure

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(A) Cellar nozzle and (B) Bresnan distributor.

(A) (B)

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Piercing nozzle. Water curtain nozzle.

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Nozzle OperationsSolid tip nozzles easy to operate

Nozzle size and tip selectionFog nozzles with rotating valves

Gallonage and pattern adjustmentsFog nozzles have more applications

than smooth bore nozzles.Review Chapter 10.Most hoselines operated from

crouching or kneeling position

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Small-Diameter HandlinesTypically 38, 45, or 50 mm (1½, 1¾,

or 2 inches) in diameter Flow from 400 to over 1,000 L/min

(100 to over 250 gpm)When flowing at lower volumes,

operated by one personFog and solid tip nozzles can be used

for small lines.Ease of mobilityNumber of personnelExtinguishing ability

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Medium-Diameter Handlines

65 to 77 mm (2½-inch or 3-inch hose) Solid tip and fog nozzlesFlow from 625 to 1,200 L/min (165

to 325 gpm )65 mm (2½-inch) hose is standard

size hoselineLarge commercial structures

Require two or more personnel to operate

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Master Stream DevicesCapable of 1,400 L/min(350 gpm)Artillery of fire serviceLarge volumes of water Apparatus-mounted or secured

properlyOne person to operate

Lack of mobility

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Stream Application, Hydraulics, and Adverse Conditions

Applications of fire streams vary Method of fire attackConditions encountered Including environmental factorsWater supply

Proper pressure and flowHydraulics

Improper hydraulic calculations are the leading cause of poor fire streams

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Direct, Indirect, andCombination Attack

Direct fire attackIndirect fire attackCombination attack

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Firefighter directly attacking a fire.

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Firefighter using indirect attack by applying water into room and then closing the door.

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Basic Hydraulics, Friction Loss, and Pressure Losses in Hoselines

HydraulicsPressureFlowMoving water through hoselines,

nozzles and appliances requires forces that act positively and negatively to achieve flow.MassPressure

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Friction LossThe loss of energy from the

turbulence, or rubbing, of the moving water through the hose

Pump operator compensates for friction loss by increasing the pump pressure for the correct pressure to the nozzle.

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Friction Loss PrinciplesFriction loss is based on four principles:Friction loss varies directly with the length of

the hose if all other variables are held constant.Friction loss varies approximately with the

square of the flow.When the flow remains constant, friction loss

varies inversely with the hose diameter.For any given velocity, the friction loss will be

about the same regardless of the water pressure.

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Pump Discharge PressureDischarge pressure of a pump: PDP

= NP + FL ± E + APump Discharge PressureNozzle PressureFriction LossElevation Appliance loss

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Example for friction loss and pump discharge pressure calculations.

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Adverse ConditionsTwo types: natural and man-madeNatural

Wind and wind directionRain, snow, hail, tree branches, wires Gravity and air friction

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Lessons LearnedFire streams

Solid tip and fog nozzlesNozzle should match fire conditions and

department resourcesCorrect hydraulics calculationsEffective use of nozzles and fire

streams on the fireground