Fire Detection and Suppression Chapter 4 Fire Pumps.

Fire Detection and Suppression

Chapter 4

Fire Pumps

Fire Pumps4-2

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 Pumps4-3

Common Fire Pump Types

• Split-case pumps (see Fig. 4.2 in manual) — Horizontal: not self-priming

(Continued)

Fire Pumps4-4


— Horizontal: not self-priming

(Continued)

Fire Pumps4-5

Common Fire Pump Types— Single-stage and multiple-stage

— Maintenance– Packing gland

– Wear rings

Fire Pumps4-6


• Split-case pumps (cont.)— Vertically mounted

Fire Pumps4-7

Common Fire Pump Types• Vertical shaft turbine pumps

(Continued)

Fire Pumps4-8

Common Fire Pump Types— Pressurized water source

Fire Pumps4-9

Pump Drivers

• Engines or motors used to turn the pump

• Power requirements

• Types— Electric motors

– Required power

(Continued)

Fire Pumps4-10

Pump Drivers– Mounting

(Continued)

Fire Pumps4-11

Pump Drivers– Mounting (cont.)

– Maintenance(Continued)

Fire Pumps4-12

Pump Drivers

• Types (cont.)— Diesel engine drivers

– Engine power

– Gear drives

– Engine requirements

– Cooling system

– Fuel storage

– Maintenance(Continued)

Fire Pumps4-13

Pump Drivers

• Types (cont.)— Steam turbines

– Horizontal and vertical shaft

– Limited feasibility

Fire Pumps4-14

Pump Controllers

• Govern pump operation

• Controllers for electricmotor-driven pumps— Switches

— Multiple pumpsconnected in parallel

— Manual shutdown

(Continued)

Fire Pumps4-15

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 Pumps4-16

Pump Controllers (cont.)

— Pressure recording device

— Manual shutdown

— Weekly startup

Fire Pumps4-17

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 Pumps4-18

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 Pumps4-19


• 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 Pumps4-20


• 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 Pumps4-21


• 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 Pumps4-22


• Component arrangement— Typical arrangement

(Continued)

Fire Pumps4-23


— Additional bypass line

(Continued)

Fire Pumps4-24


— Horizontal-shaft pump installation (See Fig. 4.23 in manual)

— Vertical-shaft pump installation (See Fig. 4.24 in manual)

• Standard performance specifications: NFPA 20, Standard for the Installation of Centrifugal Fire Pumps

Fire Pumps4-25

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 Pumps4-26


• 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 Pumps4-27


• 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 Pumps4-28

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)

Fire Pumps4-29


• 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)

Fire Pumps4-30



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)

Fire Pumps4-31



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)

Fire Pumps4-32


• Acceptance test on an electric horizontal split-case pump (cont.):— Repetitions

– Manually controlled

– Automatically controlled

– Electrically driven pump

(Continued)

Fire Pumps4-33


• 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 Detection and Suppression Chapter 4 Fire Pumps.

Documents

Transcript of Fire Detection and Suppression Chapter 4 Fire Pumps.