0. Fire Detection and Suppression
Chapter 4
Fire Pumps

1. Fire Pump Functions
The main function of a fire pump is to increase the pressure of the water that flows through it.
Inadequate or nonexistent municipal water supply system
Sprinkler systems and standpipe systems
Fire Pumps

2. Common Fire Pump Types Split-case pumps (see Fig. 4.2 in manual)
Horizontal: not self-priming
(Continued)
Fire Pumps

3. Common Fire Pump Types Horizontal: not self-priming (Continued)
Fire Pumps

4. Common Fire Pump Types Single-stage and multiple-stage Maintenance
Packing gland
Wear rings
Fire Pumps

5. Common Fire Pump Types Split-case pumps (cont.) Vertically mounted
Fire Pumps

6. Common Fire Pump Types Vertical shaft turbine pumps (Continued)
Fire Pumps

7. Common Fire Pump Types
Pressurized water source
Fire Pumps

8. Pump Drivers Engines or motors used to turn the pump
Power requirements
Types
Electric motors
Required power
(Continued)
Fire Pumps

9. Pump Drivers
Mounting
(Continued)
Fire Pumps

10. Pump Drivers
Mounting (cont.)
Maintenance
(Continued)
Fire Pumps

11. Pump Drivers Types (cont.) Diesel engine drivers Engine power
Gear drives
Engine requirements
Cooling system
Fuel storage
Maintenance
(Continued)
Fire Pumps

12. Pump Drivers Types (cont.) Steam turbines
Horizontal and vertical shaft
Limited feasibility
Fire Pumps

13. Pump Controllers Govern pump operation
Controllers for electric motor-driven pumps
Switches
Multiple pumps connected in parallel
Manual shutdown
(Continued)
Fire Pumps

14. Pump Controllers (cont.)
Diesel engine controllers
Main function is to close the circuit between the storage batteries and the engine starter motor.
Alarm and signal devices
(Continued)
Fire Pumps

15. Pump Controllers (cont.)
Pressure recording device
Manual shutdown
Weekly startup
Fire Pumps

16. Pump Installation Components and Accessories
Pipe and fittings
Materials
Valves
Standards
Suction piping: NFPA 24, Standard for the Installation of Private Fire Service Mains and Their Appurtenances
Discharge piping: NFPA 24 and NFPA 13, Standard for the Installation of Sprinkler Systems
Sizing (Continued)
Fire Pumps

17. Pump Installation Components and Accessories (cont.)
Relief valves
Prevent pressures that are high enough to damage system piping or fittings
Required only if pressure at churn is high enough to damage system components
Sizing
(Continued)
Fire Pumps

18. Pump Installation Components and Accessories (cont.)
Circulation relief valve: provides enough water flow into and out of the pump to prevent the pump from overheating when operating at churn against a closed system
Test equipment
Test manifold
GPM metering device
(Continued)
Fire Pumps

19. Pump Installation Components and Accessories (cont.)
Pressure maintenance pumps
Prevent false starts due to fluctuations in pressure of water supply to pump
Small-capacity, high-pressure pumps that maintain constant pressure on system
(Continued)
Fire Pumps

20. Pump Installation Components and Accessories (cont.)
Gauges
Horizontal split-case pumps and vertical shaft pumps
One gauge near discharge port
One gauge near intake
Vertical turbine pump: single gauge on discharge side
(Continued)
Fire Pumps

21. Pump Installation Components and Accessories (cont.)
Component arrangement
Typical arrangement
(Continued)
Fire Pumps

22. Pump Installation Components and Accessories (cont.)
Additional bypass line
(Continued)
Fire Pumps

23. Pump Installation Components and Accessories (cont.)
Horizontal-shaft pump installation (See Fig in manual)
Vertical-shaft pump installation (See Fig in manual)
Standard performance specifications: NFPA 20, Standard for the Installation of Centrifugal Fire Pumps
Fire Pumps

24. Testing, Inspection, and Maintenance
Testing fire pumps
Piping: hydrostatic testing
Acceptance testing
Certified shop test curves
Standard performance points:
1. Maximum of 140 percent of rated pressure at 0 gpm.
2. Minimum of 100 percent of rated pressure at 100 percent of rated flow.
3. A minimum of 65 percent of rated pressure at 150 percent of rated flow.
(Continued)
Fire Pumps

25. Testing, Inspection, and Maintenance
Equipment needed for pump tests
One section of 2 1/2-inch or larger hose for each hose connection on the test header
One Underwriters playpipe for each hoseline
Method for safely securing playpipes
Pitot tube and gauge
Method of measuring pump speed
Voltmeter and ammeter
(Continued)
Fire Pumps

26. Testing, Inspection, and Maintenance
Conversion of velocity pressure to gpm:
Q=(29.83)(Cd)(D2)(√P)
Where:
Q=Flow in gpm
Cd=Coefficient of discharge
D=Discharge orifice diameter
P=Nozzle pressure
(Continued)
Fire Pumps

27. Testing, Inspection, and Maintenance (cont.)
Acceptance test on an electric horizontal split-case pump
Step 1: Calculate the expected pitot pressure for 100 percent and 150 percent of the rated flow.
Step 2: Connect all the hoselines and nozzles.
Step 3: Close the indicating control valve that separates the pump from the fire system.
(Continued)
Instructor’s note: Include the additional details below in your discussion of steps 1–3.
Step 1: Calculate the expected pitot pressure for 100 percent and 150 percent of the rated flow by algebraically manipulating Equation 4.6.
Step 2: Connect all the hoselines and nozzles. Make sure that all nozzles are securely fastened in place All hose valves should be closed, and the control valve in the pipe to the test header should be closed.
Step 3: Close off the indicating control valve that separates the pump from the fire system. This will allow testing of the pump without subjecting the system piping to possible water hammer.
Fire Pumps

28. Testing, Inspection, and Maintenance
Acceptance test on an electric horizontal split-case pump (cont.):
Step 4: Connect the ammeter and voltmeter to the test leads in the controller or at any other appropriate location.
Step 5: If using a handheld revolution counter to measure pump speed, remove end plate of motor for access to shaft.
(Continued)
Instructor’s note: Include the additional details below in your discussion of steps 4 and 5.
Step 4: Connect the ammeter and voltmeter to the test leads in the controller or at any other appropriate location.
Step 5: If a handheld revolution counter is being used to measure pump speed, the end plate of the motor should be removed for access to the shaft. Because both the motor and the pump will be rotating at the same speed, measuring the speed of the motor also gives the speed of the pump. Proper attention to safety is critical with respect to any rotating equipment. Loose fitting clothing or ties should not be worn.
Fire Pumps

29. Testing, Inspection, and Maintenance
Acceptance test on an electric horizontal split-case pump (cont.):
Step 6: If end of shaft is not accessible, use a strobe-type tachometer.
Step 7: Start the pump.
Step 8: Open the control valve in the line leading to the test header and open the hose valves for the first gpm measurement.
(Continued)
Instructor’s note: Include the additional details below in your discussion of steps 6–8.
Step 6: If the end of the shaft is not accessible, a strobe-type tachometer can be used. To establish the speed of the pump using the tachometer, the shaft may be marked with a piece of chalk and the strobe impulse adjusted until the rotating chalk mark appears to be standing still. The pump speed can then be read from the tachometer dial. Several modern styles of digital tachometers are available. The most common variety uses a small strip of reflective tape that is placed on the shaft. The handheld sensor counts the rate of reflections as the shaft rotates.
Step 7: With everything ready, the pump can be started. Initially, the pump should be operating against a closed system with no valves open and with no water flowing. This is the churn or shutoff phase. The pump can be started manually or, if equipped to start automatically, should be started by bleeding off the water pressure. Once the pump is operating, both the suction and discharge pressures should be read and recorded, the rpm measured, and voltage and current readings taken. While the pump is operating at churn, the circulation relief valve should have opened automatically and be flowing a solid stream of water. If water is not flowing, the relief valve can be adjusted with a crescent wrench until water begins to flow.
Step 8: Open the control valve in the line leading to the test header and open the hose valves for the first gpm measurement.
Fire Pumps

30. Testing, Inspection, and Maintenance
Acceptance test on an electric horizontal split-case pump (cont.):
Step 9: Open and adjust sufficient lines to exact required pitot pressures for 100 percent of rated flow.
Step 10: When all readings are complete and recorded, open and adjust additional hoselines to the exact required pitot pressures for 150 percent of the rated flow.
(Continued)
Instructor’s note: Include the additional details below in your discussion of steps 9–10.
Step 9: Sufficient lines must be opened and adjusted so that the exact required pitot pressures for 100 percent of the rated flow is read on the pitot gauge. While the velocity pressures are being measured outside, the rpm, voltage, current, discharge, and suction pressures are to be measured inside the pump room. When the first line is opened, the circulation relief valve should again be checked. When the first line was opened, the relief valve should have closed off. If it continues to flow a solid stream, further adjustment is needed.
Step 10: When all readings are complete and recorded, the additional hoselines are opened and adjusted to the exact required pitot pressures for 150 percent of the rated flow. This usually requires flowing all of the hoselines to achieve 150 percent of the rated flow. It is important to calculate ahead of time what pitot pressure is needed at each nozzle to give both the 100 percent and the 150 percent points. It is convenient if the total flows required are divided by the number of hoselines to be used to determine the flow required from each line. In this way, the pitot reading required at each nozzle will be identical.
Fire Pumps

31. Testing, Inspection, and Maintenance
Acceptance test on an electric horizontal split-case pump (cont.):
Repetitions
Manually controlled
Automatically controlled
Electrically driven pump
(Continued)
Fire Pumps

32. Testing, Inspection, and Maintenance
Acceptance test on an electric horizontal split-case pump (cont.):
Evaluating data
Performance curves
Pump speed
Voltage and current for electrically driven pump
Acceptance test on a vertical shaft electric pump
Acceptance test on a diesel driven pump
Fire Pumps