Fire Pump Installations PDF

Fire Extinguishing OBJECTIVE • Chapter 5 === 5 Describe the purpose, operation, and maintenance of fire pumps. FIRE PUMPS INSTALLATIONS A reliable flow of water for fire hoses and sprinklers is necessary for first responders and fire fighters, in order to extinguish fires. There are times when...

Fire Extinguishing OBJECTIVE • Chapter 5 === 5 Describe the purpose, operation, and maintenance of fire pumps. FIRE PUMPS INSTALLATIONS A reliable flow of water for fire hoses and sprinklers is necessary for first responders and fire fighters, in order to extinguish fires. There are times when the water supply to a facility's fire protection system may not be able to meet water volume requirements due to insufficient pressure. Larger facilities and tall buildings are particularly vulnerable. In order to meet these needs, fire pumps may be installed near the point of water supply to the facility. These pumps are designed to start automatically if the system pressure drops to a pre-determined value. Typically, centrifugal pumps (either horizontal or vertical) are used as fire pumps, though positive displacement types are permitted. Capacities of fire pumps may range from 1.6 Lis to over 300 Lis. Discharge pressures range from 280 kPa to 2000 kPa, depending on the height of the building, and the amount of water to be supplied. Fire pumps are required to meet the certification requirements outlined in applicable NFPA and Underwriters Laboratories Canada (ULC) standards. Installation of fire pumps must meet NFPA 20 - Standard for the Installation of Stationary Pumps for Fire Protection. Fire pumps must have check valves in the discharge piping so that water does not push back into the pump when it is off, especially if two pumps feed a common discharge line, and only one is running. Fire pumps usually start automatically, from a drop in pressure in the standpipe system. The drop in pressure may be due to water supplying fire hoses or activated sprinlder systems. The flow of water caused by one or two sprinklers in use would not cause a significant pressure drop to actuate the fire pump. However, multiple sprinlder head actuation may start the pump. A flow switch like that shown in Figure 18 activates an alarm when there is a high fire water flow. I Figure 18 - Flow Switch in a Fire Line 4th Class Edition 3 • Part A 5-25 Unit A-4 • Introduction to Plant and Fire Safety FIRE PUMP CHECKS Checks When Running Operators should check fire pumps shortly after start-up. Checks should include: • suction and discharge pressures • packing gland leakage, and • abnormal sounds and leaks. If the pump is driven by a gasoline or diesel engine, also check: • engine RPM • oil pressure • engine and coolant temperature, and • fuel supply pressure (if diesel engine powered). Preferably, fire pumps should be shut down manually, to ensure they keep running for a certain length of time. In some installations, a timer ensures a minimum operating time. This is usually 1 minute for each 750 watts of motor rating, with a maximum time of about 7 minutes. The use of a timer prevents frequent starts and stops. Checks When Not Running When the pump is not running, certain checks should be made as part of regular operator rounds. Below is a general checldist. 1. Verify the fire pump inlet water pressure. 2. Verify that all required inlet and outlet valves are locked open to prevent accidental closure. 3. Verify that the breaker for an electrically driven fire pump (and other auxiliary equipment) is energized and in auto. 4. Verify that the fuel supply for an internal combustion engine (usually diesel oil) is ready to be delivered to the engine when required. a) Ensure the day tank is full of fuel oil. b) Verify that supply line valves in the oil line are open. c) Ensure the fuel supply lines to the engine are primed. d) Verify that the day tank fuel pump (for supplying fuel oil to the engine) is valved correctly and functioning properly. e) Verify the day tank fuel pump power supply. The day tank pump may be battery operated, so that fuel and power can be supplied to the fire pump engine in the event of a power outage. 5. If the fire pump engine has a block heater, ensure the heater is operating and the engine is warm. 6. Check the charge and the water levels of the engine starting batteries. Make sure the battery charger is in service. 7. Verify the level of coolant and the freeze point of the engine cooling system. 8. Check the engine oil level and add if necessary. Change the lubrication oil as required. 9. Keep a regular log of the hours a diesel driver has been running. Also log the times and dates when the pump is tested. E--------------------------5-26 7 S 4th Class Edition 3 • Part A Fire Extinguishing • Chapter 5 FIRE PUMP TESTING Regular weeldy, monthly, quarterly, and annual fire pump testing is mandated by NFPA 25 Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems. It is common for Power Engineers to test start fire pumps and monitor their operation. Pump testing typically involves the following: a) Fire pump operation may set off alarms to monitoring companies or fire departments. It is necessary to notify these agencies of the dates and times when testing is to be done. If the monitoring agency is temporarily disconnected from the alarm, procedures must be in place to notify these agencies manually if a real fire occurs during the test. b) Complete the pre-start checldist, according to installer and manufacturer's instructions and site-specific procedures. c) Start the pump, according to site-specific procedures. This is usually done by simulating water use by opening a drain valve in the sprinlder system. Record the sprinlder system pressure when the pump starts, and the time it takes for the pump to come up to operating speed. d) Monitor the operation of the pump. Check and record inlet and discharge pressures of the pump. Check the pump pacldng glands for leakage and excessive temperature. Adjust the pacldng nuts, if necessary. Listen for unusual sounds and vibration. e) If driven by an internal combustion engine, observe and record the engine oil pressure, the engine RPM, the water and oil temperatures, and the fuel oil pressure whenever the engine is running. Run the test for the prescribed time (usually an hour). f) Annually, run the pump under no-flow and 150% rated capacity and compare to manufacturer's specifications. This must be conducted by a certified agency and documented. Flow tests usually involve connecting fire hoses and a flowmeters to a standpipe connection, and throttling the flow as appropriate. g) Record the results in a log book. Note that fire pumps start on loss of standpipe or sprinkler system pressure instigated by the activation of a sprinkler head, fire hose, or other standpipe connection. The resulting system pressure drop operates a pressure-sensitive switch that starts the fire pump. The fire pump continues to operate to maintain system pressure. JOCKEY PUMPS Wet systems may have small, insignificant leaks that gradually result in a drop in system pressure. If the system pressure drops below a set value, the fire pump will start unnecessarily, and the system will go into alarm. To prevent this from occurring, the system must be kept pressurized above the starting pressure of the fire pump. This is accomplished with a jockey pump. Jockey pumps are small centrifugal pumps that have only enough capacity to pressurize the standpipe in the event of small leaks. If a sprinkler head or a firehose is activated, the jockey pump cannot maintain the system pressure, and the fire pump starts. Engineers should check jockey pumps regularly to ensure they do not cycle too frequently. This would indicate a significant leak in the fire system. Electric motors and diesel engines are the most common drivers for fire pumps, although gasoline engines and steam turbines have been used. 4th Class Edition 3 • Part A 5-27 Unit A-4 • Introduction to Plant and Fire Safety == All pump drivers, auxiliary equipment, fuel storage systems, and associated electrical equipment must meet federal, provincial, and territorial regulations, which commonly reference the following codes and standards: • CSA C22.1 - Canadian Electrical Code • National Building Code of Canada • NFPA 37 - Standard for the Installation and Use of Stationary Combustion Engines and Gas Turbines • NFPA - 54 National Fuel Gas Code • NFPA - 58 Liquefied Petroleum Gas Code • NFPA 31 - Standard for the Installation of Oil-Burning Equipment In addition to federal and provincial legislation, there may be requirements to meet local codes, and those of insurance underwriters. 5-28 <-(-----------------------------4 -th __ C s_ s _E_d_ ftn_3_•_P_a_ rl_A _ Fire Extinguishing • Chapter 5 == CHAPTER SUMMARY Power Engineer may be trained as first responders. This means they must be familiar with how to identify and use the correct fire extinguisher for the type of fire. Fire extinguishers are portable containers that contain agents designed to fight particular types of fires. Because they are small, fire extinguishers are only intended for use on smaller fires contained to small areas. Class A fires (normal combustibles) are most effectively put out with water. Class B fires (flammable liquids) are best smothered or separated from the air. Class C (electrical) fires should be extinguished with non-conductive agents, as soon as the power supply to the burning equipment is shut off. Class ABC fire extinguishers are suitable for all these types of fires. Kitchen fires of vegetable or animal fats are most effectively extinguished with a special foam type fire extinguisher. Metal fires are put out with Class D extinguishing agents, each designed for a specific type of metal (there is no general-purpose Class D extinguisher for all metals). Use "PASS" - pull, aim, squeeze, sweep - as a: method of putting out a fire with an extinguisher. Sprinlders and standpipes are intended to supply water to fight larger fires. Standpipes for fire hoses can be charged with water (wet) or be filled with air (dry). Dry standpipes are charged with water quicldy when needed. Fire department connections for standpipes and sprinlders are available through outside "Y" connections. These systems may also be supplied from municipal water sources. Sprinlder systems are considered to be automatic because they are readily available, and operate without human intervention. Some special systems such as preaction and deluge sprinlders have valves that are manually activated, or activated by fire detection equipment (such as smoke and heat detectors). Preaction sprinlder systems are for special locations such as museums, or other places that want to be sure of an actual fire before the system activates. Deluge sprinkler systems are intended to supply large amounts of water with extra coverage to prevent fast-spreading fires, such as in a paper storage area. Sprinlder systems must be tested regularly to ensure their proper operation. Weeldy and monthly visual checks verify that the equipment is operational. Annual maintenance, such as flushing and flow checldng, is done according to regulations. This is usually part of the overall fire systems maintenance, testing fire alarms and other fire detection equipment. Fire pumps are kept on standby, ready for use. This ensures that adequate water pressure is available for standpipes and sprinlder systems. Regardless of whether the driver is a diesel engine or an electric motor, regular checks and testing are required to assure reliable water delivery. These tests and checks are often performed by Power Engineers. 4th Class Edition 3 • Part A 5-29