Pumper Review
Pumping at a low residual pressure
(below 20 psi) while being supplied by other apparatus is dangerous and may cause the supply hose to collapse.
Conductivity Test for foam concentrate in solution =
(conductivity of solution) - (conductivity of water) / 500
Four types of auxiliary brakes:
-Exhaust brake -Engine compression brake -Transmission output retarder -Electromagnetic retarder
For apparatus testing the air temperature should be between
0 and 110 degrees F.
NR= Fog
0.0505 x Q x (square root)NP NR = Nozzle Reaction in pounds 0.0505 = Constant Q = Total flow through the nozzle in gallons per minute NP = Nozzle pressure in pounds per square inch
Any application with compressed air foam systems
0.2 to 0.5 percent concentrate
Fire attack and overhaul with standard fog nozzles
0.2 to 0.5 percent concentrate
Any application with air aspirating foam nozzles
0.3 to 0.7 percent concentrate
Above sea level, atmospheric pressure decreases approximately
0.5 psi for every 1000 feet.
Exposure protection with standard fog nozzles
0.5 to 1.0 percent concentrate
Floating strainers may be used for water as shallow as
1 foot.
Friction loss in 2 1/2 inch hose increases
1 psi for every 10 gpm increase in flow.
Assumed flow rates for squaring the lines method
1-1/2 125 1-3/4 175 2 200 2-1/2 250
NR= Solid
1.57 x d(squared) x NP NR = Nozzle Reaction in pounds 1.57 = Constant d = Nozzle diameter in inches NP = Nozzle Pressure in pounds per square inch
For pumps rated at 1500 gpm or less, the maximum centerline distance above the surface of the water is
10 feet ; for 2000 gpm pumps, 6 feet is the maximum.
Cisterns typically range from
10,000 to 100,000 gallons.
Fog nozzle=
100 psi
Agricultural irrigation systems in some jurisdictions may flow in excess of
1000 gpm.
An inverter can be used to convert a vehicle's 12- or 24-volt DC current into
110- or 220-volt AC current.
Every fire pump that is operating properly should have a dependable lift of at least
14.7 feet
Many modern fuels, including gasoline, are blended with up to
15 percent solvent additives.
The inlet pressure at the eductor should be
150-200 psi.
At 212 degrees F, water converted to steam occupies approximately
1700 times its original volume.
The minimum foam solution application rates for ignited fuels are specified in NFPA
1911
The application ratio for durable agents as an extinguishing agent, fire line, and structure protection are
1:100 ; 1-1/2 to 2 percent ; and 2 to 3 percent
According to NFPA 1901, a sufficient number of
2-1/2 inch discharge openings must be provided to flow the rated capacity of the pump.
Class b synthetic foams last
20 to 25 years and protein based lasts approximately 10 years.
The shelf life of properly stored foam solution can be as long as
20 years.
The air content for high expansion foam ranges from
200:1 to 1000:1
High expansion foam
200:1 to 1000:1 ratio
Low expansion foam
20:1 ratio
The air content of medium expansion foam ranges from
20:1 to 200:1
Medium expansion foam
20:1 up to 200:1 ratio
Class A foam solutions do not retain their foaming properties when mixed in water for more than
24 hours.
Maximum lift is approximately
25 feet.
Fire department pumpers are rated to flow their maximum volume at 150 psi, 70 percent of their maximum at 200 psi, and 50 percent of their maximum at
250 psi at draft.
When bulk storage of foam concentrates is required, some fire departments or industrial facilities may specify
275 gallon containers, called totes.
GPM =
29.7 x d(squared) x (square root)NP GPM = Discharge in gallons per minute 29.7 = Constant d = Diameter of the orifice in inches NP = Nozzle Pressure in pounds per square inch
Friction loss coefficients single hoselines
3/4 (booster) 1,100 1 (booster) 150 1 1/4 (booster) 80 1 1/2 24 1 3/4 with 1 1/2 inch couplings 15.5 2 8 2 1/2 2 3 with 2 1/2 inch couplings 0.8 3 with 3 inch couplings 0.677 3 1/2 0.34 4 0.2 4 1/2 0.1 5 0.08 6 0.05 Standpipes 4 0.374 5 0.126 6 0.052
Apparatus should maintain a clear zone of at least
30 feet from railroad tracks to prevent contact with objects on the railroad cars.
In tandem pumping operations apparatus may be located up to
300 feet apart.
10 psi loss for flows
350 gpm or greater
The apparatus must achieve a maximum top speed of
50 mph.
Low pressure fog nozzle =
50 or 75 psi
The friction loss in older hose may be as much as
50 percent greater than that of new hose.
Solid Stream nozzle handline =
50 psi
ordinary fresh water is considered to weigh
62.4 pounds per foot cubed or 8.3 pounds per gallon.
One gallon of water weighs
8.33 lbs.
Solid stream nozzle master stream =
80 psi
Apparatus with air brakes are to be equipped with an air pressure protection valve that prevents air horns or other nonessential devices from being operated when the pressure in the air reservoir drops below
80 psi.
Handling Time
= Fill site time + Dump site time
With prober calibration
A flowmeter in good working order should be accurate to a tolerance of plus or minus 3 percent. In other words, based on a flow of 100 gpm, the display should be no more than 3 gallons higher or lower than the actual discharge.
The driver/operator should never shut down an engine immediately after a full load operation or when the temperature gauge indicates that the engine is overheated.
A hot engine should cool to the normal operating temperature. Usually an idling time of three to five minutes is sufficient.
Foam proportioning devices operate by
A venturi effect A pressurized proportioning device injects foam concentrate into a water stream at a set ratio and at a higher pressure than the water flow.
Pretrip Road Worthiness Inspection
A visual inspection of an apparatus to ensure the major components of the chassis are present and in proper working condition.
Fording
Ability of an apparatus to traverse a body of standing water. Apparatus specifications should list the specific water depths through which trucks must be able to drive.
Two basic types of intake pressure relief valves:
One that is supplied by the pump manufacturer and an integral part of the pump intake manifold. The second type is an add on device that is screwed into the pump intake connection.
If a pressure gauge is mounted at the 6-inch location, then the flowmeter must be mounted
Within 2 inches adjacent to the pressure gauge.
Pumpers built before 1991 may not be equipped with
a check valve in the tank-to-pump line.
High-expansion foam contains
a detergent base and low water content.
Floating pumps placed in an adequate water source can develop and maintain
a flow of up to 500 gpm.
The piping system and the fire pump itself must be capable of withstanding
a hydrostatic test of 500 psi before being placed into service.
To create an effective fire stream,
a lift of no greater than 20 feet is recommended. At this lift the pump operates at about 60 percent of its rated capacity.
Discharges are usually equipped with
a locking ball valve that can be operated and locked in any position.
A pumper in good working order can lift water
a maximum of 25 feet.
Force
a simple measure of weight and is expressed in pounds or kilograms. This measurement is directly related to the force of gravity.
To overcome heat where the packing rings come into contact with the shaft
a spacer, known as, a lantern or slinger ring is supplied with the packing to provide cooling.
The flow of water to the JRC respresents only
about 2.5 percent of the total flow in the system.
Durable agents are water
absorbent polymers as opposed to hydrocarbon based surfactants like Class A foam.
The impeller
acts as the disk receiving its water through the eye in its center.
Some fire departments have found that they
actually routinely dump less than 90 percent of each load.
Foam produced by a CAFS
adheres to a fuel surface and resists heat longer than low energy foam.
In order to calculate the application rate available from a specific nozzle,
divide the flow rate by the area of the fire.
The difference in reading between the flowmeter and pitot gauge
must no be more than ten percent.
The pressure at the discharge side of the eductor
must no exceed 70 percent of the eductor inlet pressure.
Driver/operators should maintain an intake pressure
of 20 to 30 psi as a relay pumper.
It is possible for a hose tender to carry a mile or more
of Large Diameter Hose.
For apparatus testing the barometric pressure should be at least 29 inches
of Mercury when corrected to sea level. (1 inch of drop in barometric pressure reduces the static lift of a pumper by approximately 1 foot).)
Water tenders must be designed to be filled at a rate
of at least 1000 gpm so that pumpers assigned to the fill site must be rated that capacity or greater.
Apparatus and personnel should maintain a collapse zone
of at least one and a half times the height of any building determined likely to collapse.
At speeds above 50 mph, an emergency vehicle may outrun the effective range
of its audible warning device. In some instances, increasing the speed of an apparatus by 20 mph can decrease the audible distance by 250 feet or more.
The master intake gauge is usually calibrated from 0 to 600 psi
of positive pressure and from 0 to 30 inches of mercury on the negative side. When the vacuum reading approaches 20 inches, the pump is nearing its capacity and is not able to supply additional lines.
Depending on the incident, apparatus, equipment, and personnel operating within 200 feet
of the base of a high-rise fire may need to be protected from falling glass and debris.
The peak hourly consumption is the maximum amount
of water used in any 1-hour interval over the course of a day.
Ceramic pump seals
offer superior resistance to warping, stretching, and corrosion.
It may take 3 to 15 times greater distance for a vehicle to come to a complete stop
on snow and ice than it does on dry pavement.
Driver/operators should maintain a residual pressure of at least 20 psi
on their master intake gauge at all times during pumping operations.
All valves should be designed and maintained so that they are easily
operable at pressures of up to 250 psi.
The atmospheric pressure decreases approximately 0.5 psi
or 1 inch of Hg for each 1000 feet of altitude gain.
To determine intake pressure a gauge should be calibrated to a range of 30 in Hg to zero for a vacuum gauge,
or 30 in Hg vacuum to 150 psi for a compound gauge.
For apparatus greater than 2000 gallon capacity, tandem rear axles, tri-axles,
or semi-trailers are required.
In order for a pumper to approach its rated capacity using a traditional strainer, there must be at least 24 inches of water
over the strainer.
Fixed piping should carry the water from the inlet to the tank. It is preferable to have an air gap in the fill
piping to avoid pressurizing the vehicle's onboard water tank.
A rotary vane pump is typically used for
priming a centrifugal pump to draft water from a static source.
Refractivity testing is accurate for
protein and fluoroprotein based foam solutions.
The open relay method consists of deploying portable folding drop tanks at each intake for
pumpers in the relay operation.
The preferred engine speed for priming
ranges between 1000 to 1200 rpm.
Depending on the manufacturer or fire department preference,
rear-mount pumps may be powered by either a split-shaft transmission or by a power take off.
A pressure reducing valve
reduces the amount of water pressure at that discharge to a specific pressure, usually 100 psi.
A bypass proportioner
reduces the friction loss across the eductor.
25 psi loss for all master stream appliances
regardless of flow.
NFPA 1962 contains placement of
relief devices.
If the pump fails to reach 22 inches of mercury during a vacuum test,
remove the apparatus from service until repairs can be made.
Due to low levels opacity and reflectivity, radiant heat easily passes through water,
rendering water curtains ineffective.
Variable-flow demand-type balanced pressure porportioners
require no flushing after use.
NFPA 1901
requires that all apparatus with a GVWR of 36,000 lb or greater be equipped with an auxiliary braking system.
NFPA 1911
requires that all tires be replaced every seven years regardless of their condition.
In jurisdictions that are higher than 2000 feet above sea level, a pumping engine overload test
should be performed as part of acceptance testing.
The vacuum reading after operating the primer control
should equal 1 inch of mercury for 1 foot of lift required.
Exhaust primers are generally found on
skid-mounted pumps or older fire apparatus.
Before backing the apparatus
sound two short blasts of the vehicle's horn.
The dump site pumper should utilize a low-level
strainer to allow for continuous drafting to a point of about 2 inches.
The water level of the static source must be at least 4 feet deep, with the strainer
submersed at least 2 feet below the surface for pumper performance testing.
Durable agents will adhere to vertical structural
surfaces for up to 24 hours.
Conductivity testing is used to ensure the quality of
synthetic based foam.
The foam concentrate inlet to the eductor should be no more
than six feet above the liquid surface of the foam concentrate.
Multiple portable tank operations are adequate for incidents
that require a flow rate in excess of 300 gpm. These operations typically use from 2 to five portable tanks.
The maximum daily consumption is the maximum total amount of water
that was used during any 24-hour interval within a 3 year period.
The voltmeter provides a relative indication of battery condition, and
the ammeter indicates the status of the vehicle's alternator and charging system.
Considering a pumper with a 1000 gallon tank,
the difference in weight between a full and empty tank is over 8000 pounds.
When engaged in a relay pumping operation,
the driver/operator may feed a supply line without having to know the volume of water flowing from the receiving pumper.
When calculating pressure loss with a master stream device,
the driver/operator must add 25 psi to the pressure loss calculation.
In a study conducted by the Society of Automotive Engineers, it was determined that in 42 percent of all collisions
the driver/operator was not aware of a problem until it was to late to correct.
The electronic governor features cavitation protection by returning
the engine to idle when intake pressure drops below 30 psi.
Intake relief valves should be set to open when
the intake pressure rises more than 10 psi above the necessary operating pressure.
On a 20-inch diameter steering wheel,
the play may be about 2 inches in either direction.
When pressures higher than 250 psi are needed
the separate third stage is engaged and used to increase the pressure from the second stage.
The formula of Class A foam includes hydrocarbon surfactants that reduce
the surface tension of water in the foam solution.
If the master intake gauge drops below 20 psi,
the throttle must not be increased any further because the pump may begin to cavitate.
During the first six months after an apparatus is received, while the paint and protective coating are new and unseasoned,
the vehicle should be washed frequently using cold water to harden the paint and keep it from spotting.
Stripping edges in the opposed discharge volutes divert
the water into two streams that are 180 degrees apart.
When more than one emergency vehicle is responding along the same route,
they should travel at least 300 to 500 feet apart.
Dual supply lines should be limited
to 900 feet.
Vehicle weight restrictions generally limit single rear axle apparatus
to a maximum capacity of 2000 gallons.
To determine pump discharge a gauge with a range of 0
to at least 400 psi should be used.
It is important to operate the pump regularly
to lubricate the semi-tight seals at the point where the shaft passes through the pump casing.
A double-suction impeller may be used
to minimize the lateral thrust of large quantities of water entering the eye of the impeller.
Some jurisdictions may specify 12-gauge, 3-wire cords with 600-volt insulation and twist-lock receptacles
to provide secure connections.
A pressure of 30,000 psi is required
to reduce water's volume one percent.
Round pump discharge pressure calculations
to the nearest 5 psi.
Clapper valves are essential
to the operation of a multistage pump.
For flows over 500 gpm parallel jet siphons should be used
to transfer water to the tank supplying the attack pumper.
Shuttle operations are divided into
travel time and handling time.
Do not use pump discharge pressures in excess of 185 psi
unless the standpipe system, hose, and appliances have been designed to function under high pressures.
Installed in-line eductors are most commonly
used to proportion Class B foam.
Centrifugal pumps are rated to pump at their maximum
volume capacity at 150 psi at draft.
Polar solvent fuels, such as alcohol, acetone, ketones, esters, are known as miscible liquids because they mix with
water.
To restore pumping capacity without replacing the entire pump
wear rings or clearance rings in the pump casing may be replaced to maintain the preferred spacing between the hub of the impeller and the pump casing.
Most priming pumps are intended to work most effectively
when the engine is set at a rate between 1000 and 1200 rpm.
The pump will discharge plain water
when the proportioner is in bypass mode.
The friction loss will be 20 percent greater
when using the condensed Q formula compared to using the FL=CQ(squared)L formula.
The concentration for hydrocarbon fuels is normally one or three percent,
while three or six percent is used for polar solvents.
The vacuum tender is able to self-fill from a static water source at a rate of up to 2000 gpm
with a lift of up to 22 feet as well as the capability of discharging its water tank at a rate up to 1750 gpm.
Rescue apparatus or other specialized units may feature fixed generator systems
with capacities of 50,000 watts or greater.
The apparatus must accelerate to 35 mph from a standing start
within 25 seconds.
The apparatus must come to a full stop from 20 mph
within 35 feet.
Condensed Q formula 5 inch hose
FL=Q(squared)/15
Condensed Q formula 4-inch hose
FL=Q(squared)/5
Front-mount pump
Fire pump mounted in front of the radiator of a vehicle and powered off the crankshaft. Maximum capacity of pump up to 1,250 gpm.
Both municipal and industrial foam pumpers may be equipped with
Fire pumps ranging in capacity from 750 to 3000 gpm or greater. Large onboard tank of foam concentrate, often contain 500 gallons or more of foam concentrate.
Tender flow rate
Flow = 0.9 x TS / Travel time + Handling time TS = Tank Size
Water shuttle flow rate
Flow= 0.9 x TS / Trip time Flow = Water shuttle flow rate in gallons per minute 0.9 = A constant to represent 90 percent of water tender tank size TS = Tank size
Driver/Operators commonly use one or more of the following methods of determining pressure loss and pump discharge pressure:
Flowmeters Hydraulic calculators Pump charts Condensed Q method GPM flowing
Six Principles of Pressure:
Fluid pressure is perpendicular to any surface on which it acts. Fluid pressure at a point in fluid at rest is the same intensity in all directions. Pressure applied to a confined fluid is transmitted equally in all directions. The pressure of a liquid in an open vessel is proportional to its depth. The pressure of a liquid in an open vessel is proportional to the density of the liquid. The pressure of a liquid at the bottom of a vessel is independent of the shape of the vessel.
For the percentage method if the percentage is 10 or less, three additional lines with the same flow as the line being supplied may be added.
For 11-15 percent, two lines may be added, and for 16-25 percent one line. When the result is over 25 percent, more water may be available, but not as much as is flowing through the first line.
Based on the NFPA 1901 standard
For every discharge outlet equipped with a flowmeter, a pressure gauge shall also be provided. These flowmeters must display flow in increments of 10 gpm or less.
Pressure
Force per unit area exerted by a liquid or gas measured in pounds per square foot, pounds per square inch, or kilopascals.
Constant flow fog nozzles are designed to operate at a nozzle pressure of 100 psi
However some nozzles may operate at 50 or 75 psi.
Automatic fog nozzles are designed to operate at 100 psi tip pressure.
However, some models may operate at 75 or even 50 psi.
Class b fuels are divided into two categories:
Hydrocarbons and polar solvents.
4 Principles of Friction Loss
If all other conditions are the same, friction loss varies directly with the length of the hose or pipe. When hoses are the same size, friction loss varies approximately with the square of the increase in the velocity of the flow. For the same discharge, friction loss varies inversely as the fifth power of the diameter of the hose. In conjunction with the unit officer, the driver/operator should consider using larger diameter hose sizes to reduce friction loss.
The driver/operator can check for excessive pump temperature manually by placing a hand on the direct pump intake.
If it is warm to the touch, the driver/operator should open a discharge, tank fill, or circulator valve.
The friction loss in a 1 1/2 inch hose is equal to the friction loss
In a 2 1/2 inch hose that is flowing four times as much water.
Some fireboats have capacities as high as 50,000 gpm.
Individual master stream devices on these vessels may discharge large volumes of water sometimes in excess of 10,000 gpm.
Centrifugal pump
Is the main pump on nearly all modern fire apparatus and is a nonpositive displacement pump.
Determining maximum lift
L=1.13 Hg L= Height of lift in feet 1.13= A constant Hg= Inches of Mercury
Pressure Correction =
Lift + Total Intake Friction Loss / 2.3
The foam proportioning systems commonly found on municipal fire pumpers are scaled down versions of those used for industrial fire pumpers
Likewise, the foam tanks are correspondingly smaller, usually ranging from 20 to 100 gallons. These tanks are often designed to be refilled directly from 5 gallon containers.
Three categories of apparatus:
Major fire fighting vehicles Rapid intervention vehicles Combined agent vehicles
Pump operator's panel:
Master pump intake pressure indicating device Master pump discharge indicating device Pumping engine tachometer Pumping engine coolant temperature indicator Voltmeter Pump pressure controls Pumping engine throttle Primer control Water tank to pump Tank-fill valve Water tank level indicator
Condensed Q Formula
May be used for operations in which the friction loss can be determined for 3-,4-, or 5-inch hose. FL=Q(squared) FL= Friction loss in pounds per square inch for 100 feet of 3 inch hose Q= Flow rate in hundreds of gallons per minute. May be used for 3-inch hose with 2 1/2 or 3 inch couplings.
Smaller apparatus, as well as some older vehicles, may be equipped with hydraulic braking systems.
Most commercial and private vehicles built since 1990 are equipped with antilock braking systems.
Paddlewheel
Mounted at the top of a straight section of the discharge pipe so that only a small portion of the device extends into the waterway.
Each discharge equipped with a flowmeter must have a digital readout display
Mounted within 6 inches of the control valve for that discharge.
Net Pump Discharge Pressure at Draft
NPDPdraft = PDP + PC NPDP= Net Pump Discharge Pressure at draft PDP= Pump Discharge Pressure PC = Intake pressure correction.
NPDPpps = PDP - intake reading
NPDPpps= Net pump discharge pressure from a positive pressure source PDP = Pump discharge pressure.
Any apparatus that achieves test results less than 90 percent
must be taken out of service or repaired.
Spring probe
Employs a stainless steel spring probe to detect water movement in the discharge piping.
A quint is an apparatus equipped with a fire pump, water tank, and hose, in addition to an aerial device and ground ladders.
According to the NFPA 1901, Standard for Automotive Fire Apparatus, the vehicle must be equipped with a pump rated at a minimum of 1000 gpm and a water tank of at least 300 gallons.
Problems that may occur during drafting operations:
Air leak on the intake side of the pump Whirlpool allowing air to enter the pump Air leakage due to defective pump packing
Three main factors influence a centrifugal fire pump's discharge pressure:
Amount of water being discharged Speed at which the impeller is turning Pressure of water when it enters the pump from a pressurized source
A piercing nozzle is designed as 3 to 6 foot hollow steel rod 1 1/2 inches in diameter.
An impinging jet nozzle is capable of flowing approximately 125 gpm at 100 psi.
Angle of approach
Angle formed by level ground and a line from the point where the front tires touch the ground to the lowest projection at the front of the apparatus.
Breakover angle
Angle formed by level ground and a line from the point where the rear tires touch the ground to the bottom of the frame at the wheelbase midpoint.
Angle of departure
Angle formed by level ground and a line from the point where the rear tires touch the ground to the lowest projection at the rear of the apparatus.
Midi-Pumper
Apparatus sized between a mini-pumper and a full-sized fire department pumper, usually with a gross vehicle weight of 12,000 pounds or greater. The midi-pumper has a fire pump with a rated capacity generally not greater than 1000 gpm.
Rotary vane pumps
Are constructed with moveable elements that automatically compensate for wear, maintaining a tighter fit with closer clearances as the pump is used. The rotor is mounted off center inside the housing. Also the distance between the rotor and the housing is much greater at the intake than at the discharge.
Positive displacement pumps
Are self priming, deliver a definite volume of water or air, and exhaust air from the pump and deliver water. These pumps are "constant flow machines" in that they produce the same flow at a given speed regardless of discharge pressure.
Application needs of Class A foam
Areas that require maximum penetration Vertical surfaces. Surface of a fuel.
All fire department pumping apparatus are rated when drafting with a minimum lift of 3 feet from the center of a pump intake to the surface of water through 20 feet of hard intake hose. A strainer is submerged at least 2 feet in a water depth of at least 4 feet.
As the lift or friction loss in hard intake hose is increased, the water supply capability of the pump decreases. The pump may only deliver about 70 percent of its capacity if lift is increased by 5 feet, 65 percent to a 15 foot lift, and 60 percent at a 20 foot lift.
This pressure is greatest at low altitudes and least at very high altitudes.
Atmospheric pressure at sea level is 14.7 psi, which is considered standard atmospheric pressure.
Square/Rectangular Pool Capacity
C = 7.5 x L x W x D C = Capacity in gallons 7.5 = Number of gallons per cubic foot L= Length in feet W= Width in feet D = Average depth in feet
Round pool capacity
C = 7.5 x π x r(squared) x D 7.5 = Number of gallons per cubic foot π = Pi, 3.14 r = Radius in feet D= Average depth in feet
FL = CQ(squared)L
FL= Friction Loss in pounds per square inch C= Friction loss coefficient Q = Flow rate in hundreds of gallons per minute L= Hose length in hundreds of feet
Specialty designed wild land apparatus are often mounted on one-ton or larger chassis, usually featuring all-wheel drive.
Commonly known as brush trucks, brush breakers, or booster apparatus, these vehicles often have pump capacities and water tanks of 500 gallons or less. However some jurisdictions operate larger apparatus with pumps up to 1000 gpm and water tanks of 1000 gallons or larger.
Elevation pressure loss in a multi story building
EP = (5 psi) x (Number of Stories -1)
EP = 0.5H
EP = Elevation Pressure in pounds per square inch 0.5 = Constant H = Height in feet
Piston pumps
Operate using a piston that moves back and forth in a cylinder. The pressure developed by this action causes intake and discharge valves to operate and causes the movement of air, water, and foam. These multi cylinder, PTO-driven pumps can provide pressures up to 1000 psi for high-pressure fog lines, or to inject foam concentrate into a water line or manifold at a higher pressure than the water pump is creating.
Relay distance
P = R + 1 / D P= Total number of pumpers needed R= Relay distance D= Distance from tables 12.1 a or 12.1 b on pg. 429
Net Pump Discharge Pressure
PC = Lift + Total Intake Hose Friction Loss / 2.3 PC = Pressure correction in psi Lift= Required lift in feet Total Intake Hose Friction Loss = Number taken from table 11.2 2.3= A constant
Pump Discharge Pressure:
PDP = NP + TPL PDP = pump discharge pressure in pounds per square inch NP = Nozzle pressure in pounds per square inch TPL = Total Pressure Loss in pounds per square inch
Percentage method
Percent Drop = (static-residual)(100)/Static
From Large to Small
Primary feeders Secondary feeders Distributors
Single-stage centrifugal pumps
Provide flow capacities up to 2,250 gpm.
According to NFPA 1901 pumpers with a capacity of 500 gpm or less should have piping capable of flowing 250 gpm.
Pumpers with a capacity greater than 500 gpm should be able to flow at least 500 gpm.
As a minimum, all fire apparatus with a rated pump capacity of 750 gpm or greater must be equipped with at least two 2-1/2 inch discharges.
Pumps rated less than 750 gpm are required to have only one 2-1/2 inch discharge. Discharges greater than 2-1/2 inches in diameter may not be located on the pump operator's panel.
NR= Fog
Q/2 = Approximate Fog stream nozzle reaction
NR = Solid
Q/3 = Approximate solid stream nozzle reaction
The lighting equipment carried on pumping apparatus may be portable or fixed.
Ranging from 300 to 1000 watts.
The driver/operator may use a flowmeter
Reading to help identify water flow issues.
High pressure fog nozzles operate at a pressure of up to 800 psi
Recommended for wild land fires as the water flow is only 8 to 15 gpm.
Flowmeters
Reduce the number of pressure calculations required of the driver/operator.
NFPA 1002
Requires that driver/operators be skilled in the performance of certain maintenance tasks.
Mini-Pumper
Small fire apparatus mounted on a pickup-truck-sized chassis, usually with a pump having a rated capacity less than 500 gpm. Its primary advantage is speed and mobility, which enables it to respond to fires more rapidly than larger apparatus.
Master stream nozzles are capable of water flow in excess of 350 gpm.
Smooth bore stream are operated at 80 psi and fog appliances at 100 psi.
Volute
Spiral, divergent chamber of a centrifugal pump in which the velocity energy given to water by the impeller blades is converted into pressure.
NFPA 414
Standard for Aircraft Rescue and Fire-Fighting Vehicles
NFPA 1071
Standard for Emergency Vehicle Technician Professional Qualifications, provides basis to train and certify fire apparatus mechanics and fire department maintenance officers.
NFPA 1001
Standard for Fire Fighter Professional Qualifications.
NFPA 1906
Standard for Wildland Fire Apparatus
NFPA 1451
Standard for a Fire and Emergency Service Vehicle Operations Training Program
NFPA 1962
Standard for the Inspection, Care, and Use of Fire Hose, Couplings, Nozzles, and the Service Testing of Fire Hose.
NFPA 1911
Standard for the Inspection, Maintenance, Testing, and Retirement of In-Service Automotive Fire Apparatus.
NFPA 1582
Standard on Comprehensive Occupational Medical Program for Fire Departments
NFPA 1500
Standard on Fire Department Occupational Safety and Health Program.
NFPA 1150
Standard on foam chemicals for fire in class a fuels.
First-Digit Method
Step 1. Find the difference in psi between static and residual pressures. Step. 2 Multiply the first digit of the static pressure by 1, 2, or 3 to determine how many additional lines of equal flow may be added. If the psi drop is equal to or less than the first digit of the static pressure multiplied by one, three additional lines of equal flow may be added. For two, two additional lines, and for three, one additional line.
Squaring the lines method
Step 1. Obtain the static pressure of the water system Step 2. Have a close idea of the volume of water initially flowed by the pumper. Step 3. Determine the additional amount of water available and square the number of lines currently flowing as well as multiply this by the original pressure drop.
Wyed hoselines friction loss:
Step 1. Q = flow rate (gpm or L/min) / 100 wyed hoselines Step 2. FL = CQ2L wyed attack lines Step 3. Qtotal = (flow in attack line 1) + (flow in attack line 2) / 100 supply hose line to wye Step 4. FL = (C)(Qtotal)squared(L) supply hoseline Step 5. Add the friction loss from the supply hoseline, one of the attack lines, 10 psi for the wye (if total flow is above 350 gpm) and elevation pressure to determine the total pressure loss.
Ensure that exhaust pipe wrap or insulation is intact and undamaged. Pay close attention to joints and flex-pipes.
While this is important on any apparatus it is extremely important on 2007 and later engines equipped with DPFs. The exhaust gas can reach extremely high temperatures during the regeneration process and exhaust leaks can damage surrounding components or set them on fire.
Friction loss in unequal length wyed or manifold hoselines.
Step 1. Q= flow rate (gpm or L/min.) / 100 wyed hoselines Step 2. FL=CQsquaredL wyed hoselines Step 3: Qtotal = (flow in hoseline 1) + (flow in Hoseline 2) / 100 Step 4. FL = (C) (Qtotal)squaredL supply line Step 5. To determine total pressure loss, the friction loss from the supply line is added, along with the wye or manifold appliance (if greater than 350 gpm) elevation loss, and the wyed line with the greatest amount of friction loss.
Siamesed lines friction loss:
Step 1: Q = flow rate(gpm or L/min.)/100 Step 2. FL=(CQsquaredL) attack line Step 3. FL=(CQsquaredL) siamesed lines Step 4. Add the friction loss from the siamese lines, the attack line, plus 10 psi for the siamese appliance (if the flow is greater than 350 gpm). Add elevation pressure to determine the total pressure loss.
Apparatus Typing
The Incident Command System, as defined by the National Incident Management System, categorizes pumping apparatus and mobile water supply apparatus based on capability.
Some fire departments operate pumpers equipped with various types of elevating devices to apply fire streams.
The articulating or telescoping devices most commonly combined with pumpers generally range in height from 50 to 75 feet.
For 1-1/2 inch hose flowing 50 to 75 gpm and 2-1/2 inch hose flowing 200 to 300 gpm
The friction loss increases by 2 psi for every 5 gpm flow increase in 1-1/2 inch hose and for every 20 gpm flow increase in 2-1/2 inch hose.
For 1-1/2 inch hose flowing 80 to 100 gpm and 2-1/2 inch hose flowing 320 to 400 gpm
The friction loss increases by 3 psi for every 5 gpm flow increase in 1-1/2 inch hose and for every 20 gpm flow increase in 2-1/2 inch hose.
For 1-1/2 inch hose flowing 105 to 125 gpm and 2-1/2 inch hose flowing 420 to 500 gpm
The friction loss increases by 4 psi for every 5 gpm flow increase in 1-1/2 inch hose and for every 20 gpm flow increase in 2-1/2 inch hose.
One type of intake pressure relief valve is supplied by the pump manufacturer, and is an integral part of the pump intake manifold.
The second type is an add-on device that is screwed into the pump intake connection. Many of the screw on type are also equipped with a gate valve.
NFPA 1901, Standard for Automotive Fire Apparatus, contains the requirements of pumper design.
The standard specifies a minimum pump capacity of 750 gpm and a water tank with a capacity of at least 300 gallons. Pump capacities larger than 750 gpm increase in increments of 250 gpm with most municipal fire departments operating pumpers of 2000 gpm or less. There are, however, many pumpers in service with industrial fire departments that exceed 2000 gpm.
Vehicle-mounted generators provide power for the apparatus floodlights as well as any portable electrically operated equipment.
These generators typically are fueled by gasoline, diesel, power-take-off, or hydraulic systems, have 110 and 220 volt capabilities, and have capacities up to 12,000 watts.
Some apparatus are equipped with banks of lights mounted on booms that are powered by electric, pneumatic, or hydraulic systems.
These installations generally have a capacity of 500 to 1500 watts per light.
Portable generators powered by small gasoline or diesel engines generally have 110 and/or 220 volt capability.
These units may be operated in the compartment of an apparatus or carried to a remote location. Portable generators are highly useful when electric power is needed remote from the position of a fire apparatus. Portable generators are available with a variety of power capacities; 5000 watts is typically the largest capacity.
Generally, 2 cubic feet per minute of airflow per gallon per minute of foam solution produces a dry foam of up to 100 gpm of foam solution.
This creates a substantial amount of foam at a 10:1 expansion ratio.
NFPA 1901 requires some type of pressure control device to be part of any fire apparatus pumping system.
This device must operate within three to ten seconds after the discharge pressure rises and restricts the pressure from exceeding 30 psi above the set level.
NFPA 1901 requires that all intakes or discharges that are 3 inches or greater be equipped with slow acting valve controls.
This feature prevents the valve movement from open to closed in less than 3 seconds.
A very close tolerance must be maintained between the pump casing and the hub of the impeller.
This opening is usually limited to .01 inch or less.
Two basic concepts for pressure relief valves:
Those that relieve excess pressure on the discharge side of the pump. Those that relieve excess pressure on the intake side of the pump.
The gpm flowing method is not applicable
To 2 1/2 inch hoseliness flowing less than 160 gpm.
Rotary pumps
Today are confined to small capacity, booster-type pumps; low volume, high pressure pumps; and priming pumps. Most of the rotary pumps today are either rotary gear or rotary-vane construction. These pumps are driven by either a small electric motor or through a clutch that extends from the apparatus drive shaft.
Travel Time
Travel Time = 0.65 + (1.7)(Distance)
Friction loss coefficients — siamesed lines of equal length
Two 2 1/2'' 0.5 Three 2 1/2'' 0.22 Two 3'' with 2 1/2'' couplings 0.2 One 3'' with 2 1/2'' couplings, one 2 1/2 0.3 One 3'' with 3'' couplings, one 2 1/2" 0.27 Two 2 1/2'', one 3'' with 2 1/2'' couplings 0.16 Two 3'' with 2 1/2'' couplings, one 2 1/2'' 0.12
For GPM flowing
Use the flow and hose line diameter to find the gpm flowing. Then multiply the gpm flowing by the length of hose to find the TPL.
An air priming system uses the compressor to supply an airline to a jet pump that creates a
Venturi Effect that primes the pump using no moving parts or lubricants.
If 2-1/2 inch pipe is used with 90 degree bends and T-fittings, the flow may be limited to 250 gpm.
Whereas, if 3 inch pipe is used with a straighter piping route, a flow as high as 450 gpm is possible through one of these intakes, which may also be used as auxiliary drafting points.
When the transfer valve is set in the pressure position
all water from the intake manifold is directed into the eye of the first impeller. Depending on the specific pump, the first stage increases the pressure and discharges 50 to 70 percent of the volume capacity through the transfer valve and into the eye of the second impeller. In a two-stage pump, the second impeller increases the pressure and delivers the water at a higher pressure into the discharge port.
Fluoroprotein foam may be made alcohol resistant with the addition of
ammonia salts suspended in organic solvents, the alcohol-resistive properties will be effective for approximately 15 minutes.
Handline nozzles range in size from 3/4-inch up to 3-inch diameter hose line
and 350 gpm is generally the maximum flow.
For apparatus testing the water temperature should be between 35 degrees
and 90 degrees F.
Low-level strainers are designed to sit directly on the bottom of a tank or pool
and allow water to be effectively drafted down to a depth of approximately 2 inches.
Apparatus equipped with pressure governors should be set in pressure mode when acting as the attack pumper
and in the rpm mode while working as a relay pumper.
Foam concentrates become more viscous in cold temperatures
and less viscous when heated.
Generally batch mixing is only used with Class A foam concentrates
and regular AFFF concentrates.
To shut down a relay each driver/operator should slowly decrease the throttle, open the dump line valve,
and then disengage the pump slow and steady.
According to NFPA 1901,
apparatus equipped with tanks of less than 100 gallons must have a tank fill line of at least 1-inch in diameter. Tanks greater than 1000 gallons must be provided with at least a 2-inch tank fill line.
In the open position the inline eductor valve allows
approximately 10 to 40 psi to flow through the piping.
Upon transmittal of Level I staging other units stop
approximately one block away from the scene in their direction of travel and await further instructions.
Tire selections for fire apparatus
are based on gross axle weight ratings for the apparatus.
The sources used to make protein foam
are hydrolyzed in the presence of lime and converted to a protein hydrolysate that is neutralized.
Expansion ratios for most fog nozzles
are in the 2:1 up to 4:1 range.
Injection foam systems
are most commonly employed in apparatus mounted or fixed fire protection systems.
Altitude impacts the production of fire streams because atmospheric pressure drops
as height above sea level increases.
Mobile water supply apparatus
as stated in NFPA 1901, are equipped with a tank capacity of at least 1000 gallons.
When considering pressure loss in an elevated waterway,
assume a loss of 25 psi for the waterway and master stream appliance.
All fire pumps meeting NFPA and Underwriter's Laboratories Inc. requirements are rated to pump their capacity
at 10 feet of lift.
JRC proportions the concentrate
at a 66.5 percent solution. the solution is then pumped into a self-educting master stream where it is further proportioned to a discharge solution of three percent.
Chimney nozzles are supplied by a booster hose and flow only 1.5 to 3 gpm
at a nozzle pressure of 100 psi.
Many power-operated transfer valves operate
at pressures as high as 200 psi.
The impeller turns
at speeds of nearly 4000 rpm when the pump approaches its capacity.
The average daily consumption is the average amount of water used per day
based on the total amount of water used in a water distribution system over the period of one year.
During relay pumping the intake pressure reading cannot
be allowed to drop below 20 psi.
In theory cavitation can be described as water
being discharged faster than it is coming into the pump.
Excessive back pressure may result in no foam concentrate
being inducted into the water.
Pumpers cannot be expected to draft water that is located 33.9 feet
below the level of the pump.
Tenders featuring pumps of 750 gpm or greater are often
called pumper/tenders.
Switching from volume to pressure
can result in the immediate doubling of the previous discharge pressure.
Pumps rated greater than 1,500 gpm
capacity may require more than one large intake connection at each location.
Most pumps are able to develop a vacuum
capacity of approximately 22 inches of mercury.
Aqueous film forming foam consists of fluorochemical and hydrocarbon surfactants
combined with solvents to create a high boiling point.
PTO driven fire pumps are most
common to initial attack, wild land, or mobile water supply applications. In the past units were limited to up to 500 gpm, however some now provide full torque as large as 1,250 gpm. The PTO unit is powered by an idler gear in the vehicle's transmission.
Attack pumpers equipped with an adjustable intake relief valve should be set between 50 and 75 psi to establish a stable operating
condition.
Rotary gear pumps
consists of two gears that rotate in a tightly meshed pattern inside a watertight case. To prevent damage to the casings, most gear pumps feature gears made of bronze or another soft metal, while a strong alloy such as cast iron is used for the pump casing.
For every 1000 feet of altitude the atmospheric pressure
decreases by approximately 0.5 psi.
Some fire pumps have been constructed using up to four impellers connect in series to
develop pressures up to 1000 psi for high pressure fog fire fighting operations.
CAFS apparatus use a standard centrifugal pump with an automatic
discharge side proportioning system.
When the pump transfer valve is in the volume position
each of the impellers takes water from a source and delivers it to the discharge. Each of the impellers is capable of delivering its rated pressure while flowing 50 percent of its rated capacity; therefore, the total amount of water the pump can deliver is equal to the sum of the stages.
Auxiliary cooling systems contain one of two auxiliary coolers:
either the marine or immersion type.
Midship pumps
feature the pump mounted laterally across the frame behind the engine and transmission. Power is supplied to the pump through the use of a split shaft gear case. Rate anywhere from 500 to 2,250 gpm.
Single portable tank operations are adequate for
fire fighting operations that require flow rates of less than 300 gpm.
NFPA 1901 requires all tenders to have the capability to dump at a minimum average
flow rate of 1000 gpm for the first 90 percent of its tank capacity.
Variable flow variable rate direct injection systems proportion
foam concentrate at rates from 0.1 to 3 percent.
A jet ratio controller allows
foam concentrate supply to be located as far as 3000 feet away from a self-educting master stream nozzle as well as an elevation change of up to 50 feet.
Inlet water pressure of greater than 10 psi will not allow
foam concentrate to enter the pump intake.
A major advantage of the self-educting nozzle is the pressure drop is much lower (10 percent or less) than most standard
foam nozzle eductors.
It may take one to two miles
for a fully loaded train to make a complete stop.
Add approximately 5 psi
for each floor above the fire department connection that will have operating fire streams.
2 feet of water all around a barrel-type strainer is the minimum
for that type of equipment.
The insurance services office came up with formulas
for the evaluating of water tender performance.
5 gallon plastic pails are commonly used containers
for the holding of foam concentrate.
When using more than one hose line of equal length and equal diameter,
friction loss calculation need only be made for one line.
When 2 hoselines of equal length are siamesed to supply a fire stream,
friction loss is approximately 25 percent less than that of a single hose line at the same nozzle pressure.
The entire priming action typically requires 10 to 15 seconds
from start to finish.
Factoring the flow in gallons per minute
from the nozzle at a given pressure, you must then subtract 10 from the first two numbers of the gpm flow. A sufficiently accurate estimation of friction loss per 100 feet of 2 1/2 inch hose is obtained.
Diesel exhaust may contain up to 100
harmful chemicals and compounds.
When monitoring the hose during testing a scribe mark may be placed where the hose and couplings meet,
if this mark is found to have moved away more than 3/8 of an inch from the coupling, stop the test and replace the hose.
Automatic chains may be ineffective
in snow deeper than 3 to 6 inches.
Side-to-side variance
in weight should not exceed seven percent.
Three types of master stream appliances
include fixed monitors, combination monitors, and portable monitors.
Hydrostatic pumps are used for auxiliary systems,
including compressed air foam systems and generators on some apparatus.
Pumps powered by gasoline or diesel engines
independent of the vehicle-drive engine are examples of auxiliary pumps. Pumping capacity of 500 gallons or less.
Selectable gallonage nozzles are designed to flow the gallonage
indicated at 100 psi nozzle pressure.
It is a general guideline to discharge 150 psi
into the FDC if no specific information is available.
The hydrostatic test for apparatus
is 500 psi for a minimum of 10 minutes.
Level I staging
is applied to the initial response of more than one fire department unit.
The forward velocity pressure
is considered flow pressure.
Level II staging
is enacted when a large number of units are responding to an incident.
Any tank, regardless of type, should be set up on a surface that is as level as possible and have a capacity of at
least 500 gallons larger than the water tank on the apparatus that will supply it.
0 psi loss for flows
less than 350 gpm
Use a bucket of water to immerse the foam pick up tube,
letting it induct water for at least one minute.
Water temperature below 35 degrees F or above 90 degrees F
may adversely impact the ability of the pump to reach capacity.
Engines produced after January 1, 2010
may be equipped with an exhaust after-treatment system called Selective Catalyst Reductant.
Foam concentrate tanks on municipal fire apparatus generally range from 20 to 200 gallons while foam pumper tenders
may carry 8,000 gallons or more of concentrate.
With the engine idling and the pump engaged,
most speedometers will indicate between 10 to 15 mph.
Fire pumps of 1250 gpm capacity must achieve prime in 30 seconds or less, and those rated at 1500 gpm
must be primed within 45 seconds.
