39-Hour Pump Operators Course Combines Theory, Practical Work

39-Hour Pump Operators Course Combines Theory, Practical Work

CAPTAIN

Fire /Rescue Training Officer

The task of driving and operating a fire department pumper is one of the most complex and difficult activities in the fire service. Unfortunately, even though this is a very demanding job, many pump operators are selected because they have had experience driving large or heavy vehicles.

Driving a pumper is just a very small part of a pump operator’s job. Selection of pump operators must be based upon knowledge of pump operation, maintenance and test, as well as driving skill.

Recognizing this fact, Montgomery County, Md., has developed a 13-session course of three-hour sessions designed to train motor pump operators.

The basic outline for the course is:

Session 1—introduction to fluids and water movement.

Session 2—basic hydraulics and problem solving.

Session 3—positive displacement and centrifugal pumps.

Session 4—pump accessories.

Session 5—operating a pumper.

Session 6—advanced hydraulics and problem solving.

Session 7 & 8—operating a pump simulator.

Session 9 & 10—actual pumper operation.

Session 11—testing and maintenance.

Session 12—review.

Session 13—final examination.

Introduction to fluids

The first session begins with a discussion of what is pressure and the difference between a weight in pounds and a pressure in pounds per square inch. Then, specific pressures related to the fire service are defined. These include:

Atmospheric pressure,

Gage pressure,

Absolute pressure,

Positive pressure,

Negative pressure,

Static pressure and

Back pressure.

Now, armed with an understanding of the forces involved, the instructor can move to some of the specific properties of fluids. This particular section covers information about water incompressibility, fluid pressure being perpendicular to the surface on which it works, and fluid pressure at a point at rest.

Other physical properties of water, such as the weight of a gallon and the weight of a cubic foot, also are covered.

Static head is now equated to back pressure and elevated water systems are covered. The method of calculating static head is shown and then the fireground method of estimating ½ psi for each foot of elevation is shown. This fact is next used for calculating back pressure in relation to standpipe elevation, difference in elevation of pumpers, and ladder pipe operations.

The first session finishes up with an excellent film, “Where’s the Water?” from Iowa State University Fire Service Extension.

When this first session is completed, the student should understand why and how water moves on the fireground. He should have the basics necessary to determine the forces involved in moving water.

Basic hydraulics

The main objective in this session is to teach the material so that the operator can develop the correct pressures needed to deliver water to the fireground. While exact formulas are covered, fireground usage is stressed.

This session starts with a discussion of water in motion and the problems this produces. Such things as loss due to the lining of the hose and loss due to bends, couplings and appliances are explained. The relationship between flow, hose diameter, length, and friction loss are shown so that the student has an awareness of why certain calculations will be done.

The calculations are done on a building block basis so that the student moves from the simple to the more complex.

The first step is to show the simplified method for determining loss in 2 ½-inch hose flowing 100 through 500 gpm. Once a few problems are worked, the basic nozzle pressures of 50 psi for straight stream hand nozzles, 80 psi for straight stream master stream nozzles, and 100 psi for fog nozzles are explained. Now the calculations can be shown for 1 ½ -inch lines.

The next building block is to move to engine pressures necessary for various lengths of preconnected lines. Once this is mastered, a second pumper is added and engine pressures for both pumpers are calculated.

Two methods used

The next move up is to 3-inch hose. Here, both formula and fireground methods are used. This enables a student to see that the approximations used on the fireground are very close to the actual values. Two pumper calculations and attack lines are used at this stage for the problems.

Calculations for dual lines of the same size and length are shown, using the fact that the water will divide evenly. Then, the engine pressure necessary for the single line using half the flow is all that must be determined. Complex charts for dual lines of the same size are not necessary.

Pump operators acquire experience through use of fire pump simulators at the training academy of the Montgomery County, Md., Department of Fire and Rescue Services. From left are Lt. Robert Hathaway, Lt. Lawrence Shamer and Technician Eldridge Brown.

Table 1 MONTGOMERY COUNTY RELAY PUMPING FROM A HYDRANT

Table 2 MONTGOMERY COUNTY DRAFTING OPERATIONS

At this point, the students are shown a small friction loss calculator which will provide the engine pressure in matters of seconds.

The students are also given several problems as a homework assignment. In addition, they must determine the flow and nozzle pressure necessary for all water-delivering appliances in their department. This includes nozzles as well as distributors, applicators, and eductors.

This session has taught the student to perform the basic calculations for most situations encountered on the fireground.

Positive displacement pumps are covered because there is still apparatus in service using them, particularly on brush-type vehicles. The various types, such as the rotary gear, rotary vane, and piston, are discussed. The need for an air chamber to smooth out the pulsations is also covered.

An excellent visual aid for this portion of the class is a small children’s toy of an operating piston pumper. Using vegetable dye in water, the operation from a simple lift pump to a pressure pump can be shown.

Coverage of a centrifugal pump begins with a description of how rapidly revolving water can develop velocity energy which is changed to pressure energy. The parts of the pump which are necessary to accomplish this are explained, using both slides and an impeller. The importance of the volute to change the velocity head to pressure head is stressed.

Other parts necessary for centrifugal pump operation are also covered at this time. These include the pump casing, clearance or wear rings, and packing.

Also covered during this session are the various methods of driving a pump: power transfer, power take-off, power from the flywheel, and power from a separate engine. The specific method of getting power to the pump, including manual overrides, are then shown.

When this session is completed, the student should have a basic understanding of how water moves into the pump, the pump is powered, and water is delivered out the discharge at an increased pressure.

Pump accessories

While the basic parts of the pump necessary to deliver water were covered in the preceding session, many other items are added to the pumps to ensure more efficient and safer operations. These include pressure control devices, transfer valves, priming devices, auxiliary cooler systems, gages, gates, and drains.

Pressure control is one of the key elements of a pump operator’s job. This fact is stressed by pointing out that excess pressure can damage hose lines, injuring fire fighters and damaging a pump. Basic methods for controlling pressure, as well as the functioning of the individual devices, are explained.

The discussion of two-stage pumps and the operation of the transfer valve explains how the two impellers act together to obtain different flows and pressures at certain engine rpm. The decision to change from the pressure mode to the volume mode is made when the flow from the pumper exceeds 50 percent of its rated capacity. This provides a fireground rule of thumb for the pump operator.

Priming devices

Because the centrifugal pump cannot create a vacuum so that water can be drafted from a static source, another method for evacuating the air must be included. The student is told about the three types of priming devices used for this purpose.

  1. Rotary positive displacement pumps are installed so that they remove the air from the pump and intake sleeve. This allows for the drafting operation.
  2. Vacuum primers are connected to the intake manifold of the engine so that the air is exhausted from the pump to the engine. Various protective devices are included to prevent water from being drawn into the engine. On diesel apparatus, a separate vacuum pump is installed.
  3. Exhaust primers use the rapidly moving exhaust gases from the engine to create a vacuum. Then, both the air from the pump and the exhaust gases are discharged to the ground.

The student also learns about the maintenance problems inherent to each type of primer as well as any manual overrides.

Auxiliary cooler

Auxiliary cooling systems are usually the least understood of all the accessories. Most instructors skip this item as being unimportant. Unfortunately, misuse can cause engine damage which can not only be expensive to repair, but can keep the apparatus out of service.

The fact that the function of the auxiliary cooler is to regulate radiator water temperature and that this is accomplished by passing radiator water through coils cooled by pump discharge water is stressed. Pump water does not mix with radiator water in the auxiliary cooler.

The pump operators are told to exercise care in opening the auxiliary cooling valve because the water is coming in at pump discharge pressure, which could be extremely high at times. They are also told about the radiator fill valve, which connects the radiator water directly to the pump discharge. The fact that this should be used only for emergency cooling is explained.

Interpreting gage readings

The discussion of gages starts with the operating mechanism for pressure, vacuum, and compound gages. Reading and interpreting various gage indications are covered, based on situations encountered on the fireground. Then, the normal readings and an explanation of what can cause abnormal readings for the other gages are explained. The additional gages discussed are water temperature, oil pressure, battery or ammeter, tachometer and water tank level.

Finally, the operation of the gates and drains are discussed. The importance of opening and closing gates slowly is stressed as a safety factor.

The location of all apparatus drains is covered to ensure that no water will remain in the pump or piping during cold weather.

When completed, the student should know the operation and working of all the accessories on a pump. When combined with the preceding session, he should understand the complete pump functioning.

Operating a pumper

The pump operator encounters four basic situations. Each is handled differently, so basic operating procedures should be stressed.

For drafting, a sequential set of standard operating procedures is established. These procedures cover such details as the sequence for installing the strainer and connecting the necessary hard sleeves, checking for closed drains and gates, and the proper position for the strainer in the water.

Next, a trouble analysis routine is developed, based on a set of symptoms which include inability to hold a prime, inability to deliver rated capacity, and inability to develop sufficient pressure.

Finally, the gage readings during drafting operations are discussed.

Hydrant procedures

Operating from a hydrant begins with a discussion of the operating parts of a hydrant, the difference between a dry barrel and wet barrel, the automatic draining feature, and the reason it is necessary to turn the hydrant fully on or off.

Standard operating procedures are also established for working from a hydrant, including normal gage indications. At this point, cavitation is also discussed so that the pump operator is aware of the dangers of trying to discharge more water than is entering the pump.

Dual pumper operation by connecting one pumper to the hydrant and a second pumper intake-to-intake to the first pumper is stressed. A discussion of the advantages and disadvantages give the operator a basis for making a decision for a dual pumper operation on the fireground.

Relay operations

Fireground conditions usually dictate that relay operations must simply grow, rather than develop according to advance planning. For this reason, the basics of a relay operation are stressed, including the problems that can be encountered. A standard operating procedure is also established for relays so that much of the work takes place automatically.

Operating a tanker shuttle on the fireground requires tremendous skill and coordination. Standard operating procedures again help to eliminate difficulties on the fireground.

The student should now know the theory of operating under fireground conditions, including hydrant, relay, drafting, and tanker shuttle.

Advanced hydraulics begins with a review of the basics already covered. Then, relay operation for large flows, including wagon pipe and ladder pipe operation is covered. Ladder pipe reaction calculations are also shown.

Estimating available flow from hydrants is shown so that the pump operator can advise the officer in charge when the requested water delivery cannot be supplied.

When finished with this session, the student should be able to perform all hydraulic calculations necessary for fireground operation.

Pump simulator

Two sessions, for a total of six hours of training, are held using a pump simulator. Here, using electronic circuitry, the student has an opportunity to learn to be a pump operator without being concerned about damaging either the pump or the engine.

The simulator authentically presents all of the gage readings for drafting, hydrant operation an relay pumping. Hydrant pressure can be varied, drains can be opened and closed, nozzle sizes and flows can be changed, hose sizes and lengths can be varied, and even a broken hose line can be simulated. With each of these changes, the corresponding reading on the gage shows as it would actually be on the fireground. In addition, a ladder pipe with a 60-foot elevation can be inserted into the problem.

Radio simulation

All communications between the instructor acting as the officer-in-charge and the students takes place via a simulated radio setup. In this way, the students are forced to communicate as they would on the fireground.

Since only three students operate the simulator at one time, several large repeater gages have been installed. These gages display intake and discharge information and are large enough to be seen by the other students. Through an amplifier system, all students hear the situation as it develops and they must perform their own calculations. These calculations can then be compared to the simulator operator’s by looking at the large gages.

In this manner, all students receive six hours of extensive pump operation practice before leaving the classroom and should be familiar with all pumping operations.

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Actual pumper operation gives each student a chance to receive hands-on experience. Two basic evolutions are involved and the class is divided in half. At the conclusion of the first session, the two groups are switched for the second session. If the class has students from departments using tankers, a third evolution is added and three groups are formed. The evolutions are organized as follows: One evolution is a hydrant operation involving a two-pumper relay. The hose lines are prepared as shown in the illustration. Ring gages are installed at each of the intakes and discharges as well as behind each fog nozzle. This ensures accurate determination of friction losses. A pitot gage is used to read the nozzle pressure of the straight tip of a deck gun.

The hydrant is then turned on and the static reading on the intake gage is noted. Pumper 2 then charges the two l 1/2-inch hand lines and its discharge pressure is checked by the instructor.

Pumper 1 now charges a single 2½inch line, and the operator calculates the correct discharge pressure and notes his intake residual pressure. The instructor then checks all actual readings on the form, Table 1.

The evolution then proceeds, moving the flow up one step at a time, with the second 2 ½-inch line being charged for 300-gpm flow, until a maximum flow of 600 gpm is reached.

The students rotate so that each spends time as a pump operator for Pumper 1 and Pumper 2 and also as a hand line operator.

Drafting procedures

The second evolution involves drafting procedures. The hard sleeves and strainer are placed in the static water source and are not removed until the evolution is completed. However, each time another operator takes over, all drains are opened and then closed to ensure that the pumps must be primed to operate.

To begin the evolution, the operator activates the priming device until the pump is primed. The static reading in inches of mercury on the intake gage is noted on a form shown in Table 2. A removable vacuum gage is installed on the intake side of the pump for this evolution so that accurate readings can be made.

The l 1/2-inch line is then charged and the discharge pressure and nozzle pressure are checked by the instructor and the values noted. When a 100gpm flow has been established, the residual reading on the intake gage is recorded.

This process continues by increasing the flow. When the deck gun is used, the water is directed back into the static water source.

Before each operator begins the drafting operation, the instructor inserts some malfunction into the pumper. Some examples of the malfunctions used are open drain, open discharge gate, pumper in wrong gear, and the strainer out of the water. The operator is then forced to go through the step-by-step trouble analysis procedures to find the fault.

A tanker evolution is established for those departments relying on this type of water supply. A pumper is placed at the static source for filling the tankers. A second pumper is placed at the fire scene and a portable, 1500-gallon drafting basin is set up. A 1-mile measured course is laid out and the tankers attempt to move enough water for the deck gun to continuously flow 300 gpm. The tankers follow the 1mile course both going to the static water source and returning to the fireground. Emphasis is placed on procedures for quick fills and quick dumps.

At the conclusion of these two sessions, the student should be able to handle a pumper in the variety of situations encountered on the fireground.

Testing and maintenance

There are three basic types of tests covered in the course material: acceptance tests, service tests, and dry prime tests.

The certification test conducted by Underwriters’ Laboratories on new apparatus is described, including the test of the pressure regulating device. The service test, which should be performed on a yearly basis by each department, is then covered. The student is shown how to set up for a service test. A comparison is then made of the certification and service tests. Any great changes in pump speed at the required discharges are an indication that repair of the pump or engine might be necessary.

The dry prime test is a monthly one which provides an indication of the ability of the pump to draft and of the fitness of the hard sleeves. The student is taught to perform this test as follows:

  1. Remove the large suction cap and make sure the intake screen is in place.
  2. Connect one section of hard sleeve to the pump intake and support the sleeve in a level position.
  3. Insert a flashlight, turned on and pointing out, in the hard sleeve.
  4. Connect the second hard sleeve and support it in a level position.
  5. Cap the hard sleeve with a piece of clear plastic and a gasket of the correct size.
  6. Drain the pump and make sure the tank-to-pump valve is closed.
  7. Close all pump openings.
  8. Operate the primer until a reading of 22 inches of mercury is shown. This will keep the plastic cover in place.
  9. Stop priming and shut off the engine.
  10. Begin timing.
  11. Look through the plastic cover to determine if the hard sleeve liner has collapsed under vacuum.
  12. With the engine stopped, listen for air leaks, which are usually audible.
  13. The vacuum reading must be at least 12 inches at the end of 10 minutes. If the vacuum reading is less, then the equipment has failed the test.

Maintenance discussed

Because fire apparatus must be dependable under the most adverse conditions, routine maintenance is important. This part of the 11th session stresses the maintenance which the pump operator is responsible for handling.

It covers such things for the pump as gaskets, oil in the priming reservoir, visual inspections for leaks and rust spots, and operating the transfer valve to ensure that it is not stuck. For the engine, the operator is taught to check the oil level, radiator water and battery water. He also learns to check the brake fluid level and to visually inspect the fan belt and power steering belt.

At the conclusion of the session, the student should be able to perform the tests necessary to ensure that the pumper can deliver on the fireground. In addition, the routine maintenance to keep the pumper operating should also be understood.

Review and final examination

A review session covers the highlights of the course. Sample questions from each of the sessions provide a thorough review for the student.

The final examination is an objective test of the student’s knowledge. The practical examination is left to each student’s department to conduct on its own equipment.

This new course has now been completed three times. The results have been gratifying. In particular, the improvement in operator ability is very great since using the simulator. The grade average on the examination has improved by eight points, while the practical sessions cover more material because of the student’s prior work on the pump simulator.

With a course such as described in this article, every department can train pump operators and not just lever pullers.

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