Chapter 7 Fire Hose Nozzles & Flow Rates~VER.1

Fire Hose Nozzles & Flow Rates

Sugar Land Fire Department

Driver/Operator—Pumper Academy

Spring 2003

Fire Nozzles & Flow Rates

Factors Influencing Fire Streams

Velocity Gravity Wind Friction with the air Operating pressures Nozzle design Nozzle adjustment Condition of nozzle orifice

Stream Types

Solid stream Fog stream Broken stream Master stream

Fog Stream Nozzles

Angle of deflection determines reduction in forward velocity and stream pattern

Wide-angle deflection produces a wide-angle fog, and a narrow-angle deflection produces a narrow-angle fog

May be produced by deflection at the periphery or by impinging jets of water or by a combination of these

Fog Stream Nozzles

Periphery—The line bounding a rounded surface; the outward boundary of an object distinguished from its internal regions

Deflection—A turning or state of being turned; a turning from a straight line or given course; a bending; a deviation

Impinge—To strike or dash about or against; clashing with a sharp collision; to come together with force.

Manually Adjustable Nozzles

Have a number of constant flow settings Supply the selected flow at the rated nozzle

discharge pressure Actual flow may differ from that indicated at

the nozzle if the driver/.operator is unable to supply the proper pressure

Most designed to supply the gallonage marked on each setting

Manually Adjustable Nozzles

Driver/operator must know flow at which nozzle is set in order to properly supply hoseline and nozzle.

Nozzles set on a low flow may not provide proper amount of water to sufficiently cool a burning fuel

Automatic Nozzles

Are also referred to as constant pressure nozzles

Are basically variable flow nozzles with pattern-change capabilities and the ability to maintain the same nozzle pressure

Maintain approximately same nozzle pressure an pattern when gallonage supplied to nozzle changes

Automatic Nozzles

Require adequate pump discharge pressure because stream may “look good”, but may not be supplying sufficient water for extinguishment or protection.

Most designed for a 100 psi discharge pressure Are commonly used in high-rise fire fighting Acceptable flow varies with hoseline size,

nozzle design, and incident demand

Automatic Nozzles

Serve as a pressure regulator—within their flow limits—for the pumper as lines are added or shut down, allowing all available water to be used continuously if desired.

Maintain a constant nozzle pressure no matter how much the pump discharge pressure is above this figure

High Pressure Fog Nozzles

Operate at pressure up to 800 psi Develop a fog stream with considerable

forward velocity but delver a relatively low volume of water

Deliver water in a very fast-moving, fine spray and may use an impinging stream

Are best used for fighting wildland fires Not recommended for structural firefighting

because they generally flow only about 8-15gpm

Handline Nozzles

Designed to be placed on mobile attack lines that can be easily maneuvered by firefighters

May be of solid, fog, or broken stream type Range in size from small booster line nozzles

for ¾” booster hose, to large fog or solid stream nozzles designed to be placed on 3” hoseline

Generally, can flow a maximum of 350 gpm

Master Stream Nozzles

Are powerful and generate a considerable amount of nozzle reaction force

May be either solid or fog streams Are usually operated at 80 psi for solid streams Are usually operated at 100 psi for fog streams Are used when handlines would be ineffective,

conditions are unsafe, or when manpower is limited

Master Stream Nozzles

Deliver large volumes of water and have a greater reach than handheld streams

Are used from fixed positions, so most of them have some means for moving the stream in either a vertical or horizontal plane or both.

Master Stream Devices

Monitor Often incorrectly referred to as deluge sets, but

unlike deluge sets, the stream direction and angle can be changed while water is being discharged.

May be one of three basic types: Fixed—Permanently mounted on apparatus Combination—May be mounted on apparatus and used as

a turret or removed and used as a portable unit Portable—Can be carried to the location where it is

needed


Turret Pipe Consists of a turret pipe mounted on a fire apparatus

deck and connected directly to the pump by permanent pipe.

Sometimes called a deck gun or deck pip Deluge set

Consists of a short length of large diameter hose with a large nozzle or large playpipe supported at the discharge end by a tripod


Has a siamese connection at the supply end Cannot change the direction or angle of the stream

while the deluge set is discharging water Aerial Elevated Master Streams

Ladder Pipe—a master stream device used in conjunction with master streams

Detachable ladder pipes most common on light-duty aerial ladders

Are attached to the rungs of an aerial ladder and are supplied by fire hose


Must be operated manually by a firefighter at the tip of the ladder or by using a rope from the ground

Are limited to vertical up and down motions May be permanently attached to elevating platforms and

prepiped aerial ladders

Prepiped waterway—permanent piping used instead of hose

Generally have the ladder pipe attached to end of the waterway, which is on the bottom of ladder

May be operated from the top, either manually or by a power control switch located there


Usually can also be operated from the turntable or pump panel area by remote power controls

May operate master stream by electric, hydraulic, or pneumatic power system

Elevating Platform Master Streams Are basically similar to those with prepiped aerial

ladders Are located on aerial platform and can be more

easily maneuvered by firefighters at tip of aerial device than can aerial master streams

Some equipped with two master streams on one platform

Water Curtain Nozzles

Produce a fan-shaped stream designed to act as a water barrier between a fire and a combustible material

May be used to protect firefighters from heat but must cover a wide area and be reasonably heavy to be effective

Absorb only convected heat from a fire; radiant heat is transmitted through the water curtain.

Nozzle Pressure & Reaction

Nozzle Reaction—force counter to the velocity of water being discharged from a nozzle; directed against the person or device holding the nozzle

Newton’s Third Law of Motion—For every action there is an equal and opposite reaction

The greater the nozzle discharge pressure, the greater the resulting nozzle reaction.

Nozzle Pressure & Reaction

Nozzle reaction to a given pressure limits the amount of nozzle pressure that can be supplied to an attack line.

Practical working limits for velocity of fire streams are within 60 to 120 feet per second

These limiting velocities are produced by nozzle pressures that range from 25 to 100 psi

Because of a greater amount of nozzle reaction, lower nozzle pressures must be used with solid stream nozzles.

Nozzle Pressure & Reaction As a rule, use 50 psi with solid stream

handlines, and no more than 65 psi if greater reach and volume are needed

Portable master stream devices equipped with solid stream nozzles should not be operated above 80 psi

Fixed master stream devices with solid stream nozzles may be operated at higher pressures as required

Solid stream nozzles used on aerial devices should be limited to a discharge pressure of 80 psi