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
Master Stream Devices
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
Master Stream Devices
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
Master Stream Devices
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
Master Stream Devices
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