CVFD Training – Pump Operations SFFMA Training Objectives 24-01.01 – 24-01.02 NET ENGINE PRESSURE • Net Pump Discharge Pressure (new term) • Actual amount of pressure being produced by the pump. • When taking water from a hydrant, it is the difference between the intake pressure and the discharge pressure. • When drafting it is the total of the intake pressure and the discharge pressure. NOZZLE REACTION • Counterforce directed against a person holding a nozzle or a device holding a nozzle by the velocity of water being discharged. • Measured in pounds • Nozzle reaction formulas NR= 1.57·d²·NP and NR= 0.0505·Q·NP POUNDS PER SQUARE INCH (PSI) • U.S. unit for measuring pressure. • Reflected on the discharge gauge • Called Pump Discharge Pressure or Engine Pressure PUMP DISCHARGE PRESSURE • ENGINE PRESSURE • Actual velocity pressure (measured in PSI) of the water as it leaves the pump and enters the hoseline. VELOCITY • Speed; the rate of motion in a given direction. It is measured in feet per second for the fire service. Water Hammer Water moving through a pipe or hose has both weight and velocity. The weight of water increases as the pipe or hose size increases. Suddenly stopping water moving through a hose or pipe results in an energy surge being transmitted in the opposite direction, often at many times the original pressure. This surge is called Water Hammer WATER HAMMER • Force created by the rapid acceleration or deceleration of water. It generally results from closing a valve or nozzle too quickly. • Can be up to seven (7) times the original pressure. GAUGES • • • • • • • • Master Intake gauge (Compound) Master Discharge gauge Discharge gauge (individual gauges) Oil Pressure Voltmeter Tachometer (engine RPM) Pump overheat indicator Engine coolant temperature gauge Master Intake Gauge • Measures positive or negative pressure • Calibrated from 0 to 600 PSI (usually) for positive and from 0 to 30 inches of vacuum for negative pressure • Provides indication of residual pressure from a hydrant or relay operation • Provides indication of maximum capacity of pump when at draft Master Discharge Gauge • Measures positive pressure • Calibrated from 0 to 600 PSI – Up to 1000 PSI on special pumpers • Measures pressure as it leaves the pump and before it gets to the individual gauges • Always reads the highest pressure the pump is producing Discharge Gauge • Individual gauges measure the pressure for each individual discharge. • Use these gauges not the master discharge gauge when flowing any line. Oil Pressure Gauge • Measures oil pressure of the motor. • Normal operating pressures vary with different brands of apparatus. • Variations from normal may indicate pending problems. Voltmeter • Provides a relative indication of battery condition and alternator output by measuring the drop in voltage as some of the more demanding electrical accessories are used. • Indicates the top voltage available when the battery is fully charged. • Measures drop when electrical demand is high. Tachometer • Records the engine speed in revolutions per minute (rpm) • It can give valuable information about the condition of the pump. • May refer to the acceptance test rating panel to check on pump efficiency (identification plate on the pump panel) Pump Overheat Indicator • Audible or visual indicator • * Overheating occurs when the pump impeller is spinning, for prolonged periods, but no water is being discharged Pump Overheat • Best place to check for overheat is right here • Best way to never overheat the pump is to always be moving water. Engine Coolant • Engine coolant temperature gauge – Shows the temperature of the engine coolant the normal operating range of the Detroit Diesel Series 60 Engine is between 192° - 205° Fahrenheit – Caution: An engine that operates too cool is not efficient. An engine that has an operating temperature that is too high may be damaged. Pump Theory and Pump Equipment TYPES OF FIRE PUMPS • Piston – Single, Multiple • Rotary – Gear • Centrifugal – Single-stage, Two-stage, Multiple-stage Pump Equipment • • • • • • • • • Centrifugal Pump Multi-stage Pumps Cavitation Pressure Relief Valves/Governors Positive Displacement Primers Manual Pump Shift Gauges Auxiliary Cooler Valves Centrifugal Pump • Components – Impeller – Eye – Hub – Vanes – Volute – Shroud – Casing Pump Impeller Vane Impeller eye Shroud Shaft opening Centrifugal Pump • Rated at draft • Can double its’ capacity with adequate positive pressure • Non-positive displacement pump • Not self priming • Cavitation occurs when RPM without corresponding increase in pressure Centrifugal Pump • Three factors influence pump discharge pressure (PDP): – 1) – 2) – 3) Incoming Pressure Speed of the impeller Amount of water being discharged • Single or Multi-Stage • Maximum Discharge Pressure @ 150 psi plus static pressure on hydrant Rated Capacity • A pump is rated @ draft, the following show the capacity @ different pressures: – 100% @ 150 psi (net pump pressure) – 70% @ 200 psi (net pump pressure) – 50% @ 250 psi (net pump pressure) Rated Capacity • When connected to a positive pressure source, the capacity of a pump can be doubled (assuming that the source is of adequate size and pressure). • The capacity of a pump can also be increased when using multiple intakes or increasing the size of the supply line. Two-Stage Centrifugal Pumps • Single vs. Multi-Stage – Pressure (series) vs. Volume (parallel) – Most operations in pressure mode – 50 % rule – Change over @ 50 psi net pump pressure – Transfer valve found on pump panel, usually with indicator light Two-Stage Centrifugal Pumps • The two-stage pump has two impellers mounted within a single housing. • Generally, the two impellers are identical and have the same capacity. • What gives the two-stage pump its versatility and efficiency is its capability of connecting these two stages in series for maximum pressure or in parallel for maximum volume by use of a transfer valve. Two-stage Centrifugal pump • Pumping in the Volume (Parallel) Position – When the pump is in the volume position, each of the impellers takes water from a source and delivers it to the discharge. • Pumping in the Pressure (Series) Position – When the transfer valve is in the pressure position, all the water from the intake manifold is directed into the eye of the first impeller. – The first stage increases the pressure and discharges 50 to 70 percent of the volume through the transfer valve and into the eye of the second impeller. – The second impeller increases the pressure and delivers the water (at the higher pressure) into the pump discharge port. Two-Stage Centrifugal Pumps • Each fire pump manufacturer has recommendations for when the transfer valve on their pump should be in the volume or pressure position. • The process of switching between pressure and volume is sometimes referred to as changeover. Pump packing • Number of drops from packing. – Water should drip, not run from packing gland • New “Ceramic” packing – Must have temperature relief valve to protect ceramic disk Cavitation What is Cavitation? Cavitation • Firefighters definition: – Water is discharged from the pump faster than it is coming in. • Cavitation: – A condition in which vacuum pockets form in the pump and causes vibrations, loss of efficiency, and possible damage. Cavitation • During Cavitation: – The pressure at the eye of the impeller falls below normal atmospheric pressure. – The water boils faster at temperatures less than normal atmospheric pressure. – Steam and air bubbles are created. – The air bubbles move outward in the impeller and into the high-pressure zone. – The air bubbles collapse, producing noise and vibration. Cavitation • To Avoid Cavitation: – Intake pressure from pressurized sources should not drop below 20 psi. – Cavitation can be recognized by the fact that increasing the engine rpm does not result in an increase in discharge pressure. TRANSFER VALVE • Only on Pressure/Volume Pumpers • Switched by: Electric switch, Pneumatic shift, Water-hydraulic, or Manual hand-wheel • Changes pump from Pressure (Series) – to Volume (Parallel) • Switched when pumping greater than 50% of the rated capacity of the pump TRANSFER VALVE • This is an electric transfer switch • Other switches can be: – Pneumatic – Hydraulic – Manual TRANSFER VALVE • This is a manual backup to the transfer switch POWER TRANSFER POWER TRANSFER • Engine to wheels • Engine to fire pump Pump drives • • • • • Mid-ship mount Front mount PTO Rear mount flywheel Mid-Ship Mount • Mid-Ship mount: a split-shaft gear case located in the drive line between the transmission and the rear axle. • Unit will pump or drive, not both. Power Take-Off • Power is taken off the transmission before it gets to the back wheels for “pump and roll” operation. • The PTO unit is powered by an idler gear in the truck transmission. Front mount pump • Power to drive comes off of the front of the crankshaft. • Pump sizes are limited to 1250 GPM max. Electric Pump Shift Electrical switch transfers power from road (driving) to pump (firefighting) Electric switch operates a hydraulic or pneumatic shift mechanism in the transfer case Pneumatic Pump Shift TYPES OF PRIMER PUMPS • ROTARY GEAR • ROTARY VANE • VACUUM • EXHAUST Positive Displacement Primers • Types – Rotary • Rotary Gear • Rotary Vane – Piston – Exhaust • Most Common - Rotary Vane • Required for Drafting Positive Displacement Primers • Rotary Gear – Commonly used in hydraulic systems – The pump imparts pressure on the hydraulic fluid by having two intermeshing rotary gears that force the supply of hydraulic oil into the pump casing chamber. Positive Displacement Primers • Rotary Vane – A rotor with attached vanes is mounted off-center inside the pump housing. – Pressure is imparted on the water as the space between the rotor and the pump housing wall decreases. • Piston – Pump using one or more reciprocating piston to force water from the pump chamber. Vacuum Primer • Used only on gasoline engine driven fire apparatus. Positive Displacement Primers • Exhaust Primers – Exhaust primes are still found on some older pieces of apparatus. – Exhaust gases from the vehicle’s engine are prevented from escaping to the atmosphere by the exhaust deflector. – The gases are diverted to a chamber where the velocity of the gases passing through a venturi creates a vacuum. Venturi Primer Venturi Primer Positive Displacement Primers • “Older” priming pumps require an oil reservoir. • “New” priming pumps are environmentally safe requiring no priming oil. • Both make a distinctive sound when operating Positive Displacement Primers • Most are electrically driven • For pumps larger than 1250 GPM capacity, operate no more than 45 seconds. • May overheat if used for greater period of time PRESSURE RELIEF SYSTEMS Intake Pressure Relief Valves Pressure Relief Valves Pressure Governors Intake Pressure Relief Valves • Piston intake relief valves decrease the potential for a water hammer. • Two types of pressure relief devices: – Piston intake relief valve – Dump valve (on pump) – Should be preset @ 100 PSI – Can be set from 50 to 175 PSI Intake relief valves-dump valves • Relieves pressure from incoming supply lines, before it goes into the pump. Pressure Relief Valves Waterous PRV Hale PRV Pressure Relief Valves • Pressure relief valves must be set while pumping the desired pressure with water flowing. • Must be set at highest pressure necessary (gate back other lines). • Pressure relief valves do not provide cavitation protection. Pressure Relief Valves • They prevent an excessive amount of pressure being transferred to another line. • Engine rpm will not fluctuate as lines are opened or closed. • Pressure Relief Valves divert water internally. Relief Valve Operation Manual Throttle • Operated via a cable to the fuel system. • CCW to increase and CW to decrease speed. • Red button in center is the Emergency ShutDown. Pressure Governors • Pressure governors regulate engine pressure by adjusting engine rpm to compensate for attack lines being opened or shut. • This prevents an excessive amount of pressure being transferred to another line. • Engine rpm will fluctuate as lines are opened or closed. Pressure Governors • Pressure governors must be set while pumping the desired pressure. • Must be set at highest pressure necessary (gate back other lines) • Pressure governors provide cavitation protection. – If the pressure governor senses an increase in rpm without a corresponding increase in pressure, the engine will return to idle after 3-5 seconds. Electronic Pressure Governor • Seagraves version Electronic Pressure Governor • Quality version Electronic Pressure Governor • Detroit Diesel Fire commander • On all E-One Fire Apparatus Movie Time “Pressure Governor Video” Manual Pump Shift Manual Pump Shift • • • • • Provides back-up Usually located on pump panel Often require two people to operate Back-up throttle may have to be used Exercise manual shift often (weekly) Auxiliary Coolers Auxiliary Coolers • • • • Allows water from pump to cool engine Use when temperature exceeds normal level Close when temperature returns to normal Keep in closed position Auxiliary Cooling Systems • Two basic types – Immersion – Marine • System uses water from the pump which is circulated through a closed system to decrease the temperature of the coolant found in the radiator Auxiliary Cooling Systems • Auxiliary cooling devices should be used when the temperature of the engine is greater than the manufacturer recommends. • When opened, the auxiliary cooler will temporarily decrease the engine temperature, allowing time to remove attack crews and move another apparatus into place to resume operations. Auxiliary Cooling Systems • Some manufacturers supply a radiator fill valve that can be used to fill the radiator if the coolant level drops too low for effective cooling. • If used, the cooling system must be serviced system flushed and refilled with the correct amount of antifreeze. Valves • • • • • • • • Main intake valve (suction), keystone, piston, MIV* Auxiliary intake valve (2½)* Tank-to-pump valve Tank fill valve Discharge valve Pump drain valve Discharge drain valve Intake drain valve Large Intake Valves Small Intake Valve • 2 ½” intake valve connects directly into the large intake piping • 2 ½” female swivel • Intake flow capacity 1000+ GPM Water Supply Water Supply • Booster tanks • Positive pressure sources – Hydrants and other pumps • Drafting Booster Tank • • • • • Sizes Tank-to-pump valve Use only one handline Obtaining positive water source Refill as soon as possible Tank-to-Pump Flow Test • This test must be conducted on all apparatus that are equipped with a water tank. • NFPA 1901 states that piping should be sized so that pumps with a capacity of 500 gpm or less should be capable of flowing 250 gpm from their booster tanks. Tank-to-Pump Flow Test • Pumps with capacities greater than 500 gpm should be able to flow at least 500 gpm from their booster tanks. Hydrant Operations • • • • Two types of hydrants Steamer should face street Blue reflectors assist in locating Should be color coded to main size or GPM flow • MUD Districts may not color code • Private hydrants-Apartments, Businesses may or may not be maintained Hydrant Operations • When opening a dry barrel hydrant, be certain to open it all the way. • If it is not opened fully, the drain valve at the base of the hydrant may be open at the same time water is coming in from the main. • This flow of water washes away the gravel that is supporting the body of the hydrant. Hose and Nozzles • Limitations – The limitations with fire hose deal specifically with GPM and friction loss, as well as pressure limits. – The limitations of nozzles deal specifically with capacity and function. Pump Discharge Pressure • Pump Discharge Pressure = Nozzle Pressure + Friction Loss + Appliance Loss + Pressure Due To Elevation Changes PDP = NP + TPL PDP = Pump discharge pressure NP = Nozzle pressure in psi TPL = Total pressure loss in psi (appliance, friction and elevation losses) Pump Discharge Pressure Fire Service Hydraulics • Calculating Additional Water Available When a pumper is connected to a hydrant and is not discharging water, the pressure shown on the intake gauge is the static pressure. When the pumper is discharging water, the pressure shown on the intake gauge is the residual pressure. Fire Service Hydraulics • Calculating water (cont..) The difference between the two pressures is used to determine how much water is available, and consequently the number of additional lines available. Percent Drop = (Static - Residual)(100) Static Fire Service Hydraulics • Example: A pumper is supplying one line with 250 gpm flowing. The static pressure was 70 psi and the residual pressure is 63 psi. How many lines can be added? • Percent drop = (70 - 63)(100) 70 (7)(100) = 700 = 10 psi drop 70 70 Fire Service Hydraulics Water Available Table Percent Decrease Water Available 0 - 10% 3 x Amount 11 - 15% 2 x Amount 16 - 25% Same Amount Over 25% Less than is being delivered Elevation Pressure • Water exerts a pressure of 0.434 psi per foot of elevation. • When a nozzle is operating at an elevation higher than the apparatus, this pressure is exerted back against the pump. • To compensate for this pressure “loss,” elevation pressure must be added to friction loss. *Elevation Pressure* • Formula for multi-story buildings: – (EP)=5psi x (number of stories -1) • Formula for elevation pressure – (EP)=0.5H Elevation Pressure • EP=0.5H – EP = Elevation pressure in psi – 0.5 = A constant – H = Height in feet Pumping Operations PRESSURIZED OPERATIONS • HYDRANT-MOST COMMON • RELAY OPERATIONS • BOOSTER TANK Standpipes and Sprinklers • Pumpers will generally position as close as possible to the sprinkler or standpipe FDC. • This location should be established during preincident planning activities. • There are situations when pumpers supporting sprinklers or standpipes must give priority to other fire apparatus (aerial apparatus). Standpipes and Sprinklers • Fire Department Connection (FDC) usually have a 2 ½” swivel connection. • Hook up a minimum of two 2½ hoselines or one 3” hoseline. (textbook) • LDH hose should be used with adapter (real life) • Reverse lay to nearest hydrant Standpipes and Sprinklers • It is a general rule of thumb that one 1000 gpm rated pump should supply the FDC for every 50 sprinklers that are estimated to be flowing. PRV Systems • Pump the designed pressure, if known. • If the designed system pressure is unknown: – 100 psi + 6 psi per floor to the top floor of the zone • When pumping into a PRV system, the standpipe outlet pressure cannot be raised above its designed pressure. Non-PRV Systems • Standpipe: – Fog Nozzle: 150 psi + 5 psi per floor – Solid Stream 65 psi + 5 psi per floor • Sprinkler: – 150 psi + 5 psi per floor • Elevation loss is calculated to the fire floor • Mixed systems PRV & Non-PRV should be treated as a Non-PRV FDC Impairments • Frozen swivel • use a double male with a double female • Unusable due to vandalism • connect hose at the first-floor level riser • PRV’’s limit pressure and volume going out or in! DRAFTING •Primary water source for rural fire protection •Portable water supplies •Static water supplies Drafting • 3 primary considerations for selecting a site; 1) Amount of water available 2) Type of water available 3) Location accessibility • Source should have 24 inches of water above and below the strainer Drafting • All fire pumps meeting NFPA and Underwriter’s Laboratories requirements are rates to pump their capacity at 10 feet of lift. • If the lift is less, the capacity is higher. • If the lift is greater, the capacity decreases. Drafting • Theoretical Lift – In the U.S. system of measurement, at sea level a pump could theoretically lift water 33.8 feet. • Maximum Lift – The maximum lift is no more than 25 feet. • Dependable Lift – The height a column of water may be lifted in sufficient quantity to provide a reliable fire flow. Drafting • The maximum lift considered reasonable for most fire department pumpers is about 20 feet. • At 20 feet of lift, the amount of water that can be supplied is only about 60% of the rated capacity of the pump. Drafting • • • • • • Use side intakes Close pump to tank valve Remove keystone or piston intake Connect hard suction Can prime either in or out of pump gear When in pump gear, increase rpm’s to 1000 to 1200 and pull primer for not more than 45 seconds. Drafting • Priming typically requires 10 to 15 seconds. • If priming is not obtained in 30 seconds, stop and check for problems. • Most common problem is air leak. • After pump has been primed, increase pump pressure to 50-100 psi prior to opening any discharge. • Open discharge valve SLOWLY. • If pressure drops, momentarily engage primer. Pump & Dump Multiple Draft Tanks Relay Operations Relay Pumping • Necessary when the required GPM flow of the attack pumper cannot be met because of friction loss in the supply line • Pump pressure is based on GPM needed and distance between pumpers. • 20-50 psi residual in addition to friction loss • Relay initiated by pumper at water source. Relay Pumping • Intermediate pumpers - close pump to tank valve, open 2½” discharge until water discharges, close discharge, place in pump gear and open supply to next pumper • Discharge pressures should not exceed 200 psi. If pressure required to supply water is greater than 200 psi, another pumper or additional lines are needed. Relay Pumping • Relay is designed to deliver volume, not pressure • Relay is terminated by attack pumper, by decreasing pressure, followed by next pumper in relay, etc.. DUAL PUMPING OPERATION Dual Pumping • One strong hydrant may be used to supply two pumpers. • One pumper is connected to the hydrant to inside of the intake. • The second pumper is connected to its intake side for the first pumper. • The pumpers are connected intake to intake. DUAL PUMPING SET-UP (HIGH-VOLUME SET-UP) E 45 E7 TANDEM PUMP OPERATION Tandem Pumping • Is a short relay for high rise buildings (This will be a high pressure operation). • Becomes necessary after 40 stories (roughly 300 psi). • High pressure engines reverse lay from the FDC to a safe area (falling glass). • Supply engine will reverse lay to the hydrant. TANDEM PUMPING SET-UP (HIGH-PRESSURE RELAY) E/O E/O E7 E 45 60 STORY BLDG. Supplemental Pumping L93 E61 E70 E52 Supplemental Pumping E70 L 93 E61 E52 Questions Basic Principles of Hydraulics • Excessive Pressure- causes may include incorrect calculation of total engine pressure, shutting down of additional lines or opening of intake without the use of pressure governor • Water Hammer- force created by the rapid deceleration of water. It generally results closing a valve or nozzle too quickly! from Basic Principles of Hydraulics • Static Pressure - stored potential energy available to force water through pipes, fittings, fire hose and adapters. • Residual Pressure - that part of the total available pressure not used to overcome friction loss or gravity while forcing water through pipes, fittings, fire hose and adapters. Basic Principles of Hydraulics • Normal Operating Pressure pressure found in a water distribution system during normal consumption demands. • Flow Pressure - forward velocity pressure at a discharge opening while water is flowing. Basic Principles of Hydraulics • Negative Pressure - an area with a pressure less than that of the atmosphere; when calculating engine pressure and pumping to an lower than the pump, a “negative” pressure will have to be added to the equation in order to correctly figure the engine pressure. area Basic Principles of Hydraulics • Cavitation - a condition in which vacuum pockets form in the pump and cause vibrations, loss of efficiency, and possible damage • Displacement - volume or weight of a fluid displaced by a floating body of equal weight; amount of water forced into the pump, thus displacing air Basic Principles of Hydraulics • Elevation Pressure - the gain or loss of pressure in a hoseline due to change in elevation • Flow Pressure - pressure created by the rate of flow or velocity of water coming from a discharge opening Basic Principles of Hydraulics • Friction loss - loss of pressure created by the turbulence of water moving against the interior walls of the hose or pipe • Gallons per minute - unit of volume measurement used in the U.S. fire service for water movement Basic Principles of Hydraulics • Hydrant pressure - amount of pressure being supplied by a hydrant without assistance • Head pressure - water pressure due to elevation; for every one-foot increase in elevation, 0.434 psi is gained Basic Principles of Hydraulics • Net pump discharge pressure - actual amount of pressure being produced by the pump. When taking water from a hydrant, it is the difference between the intake pressure and the discharge pressure. • Nozzle pressure - the amount of pressure required at the nozzle to produce an effective fire stream. Basic Principles of Hydraulics • Nozzle reaction - counterforce directed against a person holding a nozzle or a device holding a nozzle by the velocity of water being discharged • Pounds per square inch - U.S. unit for measuring pressure • Pressure - force per unit area measured in pounds per square inch Basic Principles of Hydraulics • Pump discharge pressure - actual velocity pressure (measured in pounds per square inch) of the water as it leaves the pump and enters the hoseline. • Velocity - speed; the rate of motion in a given direction. Principles of Pressure 1. Fluid pressure is perpendicular to any surface on which it acts. 2. Fluid pressure at a point in a fluid at rest is of the same intensity in all directions. 3. Pressure applied to a confined fluid from without is transmitted equally all directions. (fire pump) in Principles of Pressure 4. The pressure of a liquid in an open vessel is proportional to its depth. 5. The pressure of a liquid in an open vessel is proportional to the density of the liquid. 6. The pressure of a liquid on the bottom of a vessel is independent of the shape of the vessel. Fire Service Hydraulics Friction Loss the part of the total pressure lost while forcing water through pipe, hose, fittings, adapters, and appliances. The basis for fire hose calculations are the size of the hose, the amount of water flowing, the length of the hose lay, the age of the hose, and the condition of the lining. Fire Service Hydraulics • Formula’s – Friction Loss = Coefficient x Flow Rate In Gallons Per Minute/100 (squared) x Hose Length In Feet/100 FL = C x Q² x L FL=C·Q²·L • FL = Friction loss in hose • C = Coefficient, a given number for each size of hose • Q = GPM flow through the hose • L = Hose length FL = C x Q² x L C A given number ? Q² Know or decide x ?__ 100 L See, know, or decide x ?__ =FL 100 Fire Service Hydraulics • Friction Loss Coefficients 1 3/4” - 15.5 2 1/2” - 2.0 3” - .80 4” - .20 GPM = 29.7 x d² x NP GPM = discharge in gallons per minute 29.7 = a constant d² NP = diameter of the tip in inches/squared = nozzle pressure in psi