Fire Detection and Suppression Chapter 4 Fire Pumps 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 4-1 Fire Pumps Common Fire Pump Types • Split-case pumps (see Fig. 4.2 in manual) — Horizontal: not self-priming (Continued) 4-2 Fire Pumps Common Fire Pump Types — Horizontal: not self-priming (Continued) 4-3 Fire Pumps Common Fire Pump Types — Single-stage and multiple-stage — Maintenance 4-4 – Packing gland – Wear rings Fire Pumps Common Fire Pump Types • Split-case pumps (cont.) — Vertically mounted 4-5 Fire Pumps Common Fire Pump Types • Vertical shaft turbine pumps (Continued) 4-6 Fire Pumps Common Fire Pump Types — Pressurized water source 4-7 Fire Pumps Pump Drivers • Engines or motors used to turn the pump • Power requirements • Types — Electric motors – Required power (Continued) 4-8 Fire Pumps Pump Drivers – Mounting (Continued) 4-9 Fire Pumps Pump Drivers – Mounting (cont.) – Maintenance (Continued) 4-10 Fire Pumps Pump Drivers • Types (cont.) — Diesel engine drivers – Engine power – Gear drives – Engine requirements – Cooling system – Fuel storage – Maintenance (Continued) 4-11 Fire Pumps Pump Drivers • Types (cont.) — Steam turbines – Horizontal and vertical shaft – Limited feasibility 4-12 Fire Pumps Pump Controllers • Govern pump operation • Controllers for electric motor-driven pumps — Switches — Multiple pumps connected in parallel — Manual shutdown (Continued) 4-13 Fire Pumps 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) 4-14 Fire Pumps Pump Controllers (cont.) — Pressure recording device — Manual shutdown — Weekly startup 4-15 Fire Pumps 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) 4-16 Fire Pumps 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) 4-17 Fire Pumps 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) 4-18 Fire Pumps 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) 4-19 Fire Pumps 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) 4-20 Fire Pumps Pump Installation Components and Accessories (cont.) • Component arrangement — Typical arrangement (Continued) 4-21 Fire Pumps Pump Installation Components and Accessories (cont.) — Additional bypass line (Continued) 4-22 Fire Pumps Pump Installation Components and Accessories (cont.) — 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 4-23 Fire Pumps 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) 4-24 Fire Pumps 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) 4-25 Fire Pumps 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) 4-26 Fire Pumps 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) 4-27 Fire Pumps 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) 4-28 Fire Pumps 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) 4-29 Fire Pumps 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) 4-30 Fire Pumps Testing, Inspection, and Maintenance • Acceptance test on an electric horizontal split-case pump (cont.): — Repetitions – Manually controlled – Automatically controlled – Electrically driven pump (Continued) 4-31 Fire Pumps 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 4-32 Fire Pumps