Fire pumps are planned and installed to be 100% redundant under normal conditions. Since pumps with high flow rates should be used in fire protection systems, it is permitted to select and install a sufficient number of pumps provided that the calculated nominal flow rate is backed up by at least 50%.
Pump control can be pressure controlled; fully automatic or semi-automatic. In special cases, we also see that fire pumps are used with manual control.
Fire Pump Types
- Vertical In-Line Fire Pumps
• End Suction Fire Pumps
• Horizontal Splitcase Fire Pumps
• Vertical Turbine Type Fire Pumps
Alternative Engine Options for Fire Pumps:
Fire pumps can be produced with engine options such as Electric Engine, Diesel Engine, Turbine. We have already mentioned that fire pumps consist of Electric Engine Main Fire Pump, Diesel Engine Backup Fire Pump and Jockey Pump.
If it is not possible to supply the main pump with electrical energy or if the substructure cost is too high, the main pump can be selected with a diesel engine. If it is mandatory to select the main and backup pumps with electric motors, it is desirable to use a Power Transfer Panel in addition to the control panel for the second pump to be used as a backup pump and also to be supplied via an independent Generator (via a reliable energy source).
The diesel pump must be supplied together with the fuel tank. If more than one diesel engine will be used in the system, the fuel tank, supply line and return line of each diesel pump must be independent.
Choosing diesel fire pumps with radiator (heat exchanger instead of air cooled) allows the pump room ventilation system to be reduced in size to meet only the combustion air. Thus, it will be sufficient to provide only the combustion air required for the operation of the pump by increasing the combustion air required by the standard.
How to choose the fire pump?
Fire pumps are determined according to nominal flow and pressure values. Detailed risk analysis of the building or facility is performed. The facility or building is designed by selecting the appropriate extinguishing system or systems for the building or facility. The most critical area is determined. Since the most critical area is the area where the risk is the highest and the pump flow rate and rated pressure will be the highest, it is used to determine the pump capacity.
The pump capacity is calculated by using a computer-assisted hydraulic calculation software to cover the most critical area and including the hydrant flow rate that needs to be added by taking into account the hazard status of the facility. If the pump capacity is determined by simple calculation method without hydraulic calculation, it is recommended to increase the determined value by 20%.
How does a fire pump work?
Fire pump groups work by taking into account the determined and successively defined pressure drop. For this reason, the control panel of each fire pump contains an independent and defined pressure detection transducer. The pressure detection line is taken between the check valve and shut-off valve on the pump discharge line and is connected to the element that will detect the pressure drop using stainless steel pipe with orifice check valve, strainer and shut-off valves placed in the opposite direction of the flow to meet the requirements of NFPA 20.
In fire pumps, the jockey pump is activated first, if the jockey pump cannot meet the flow rate used, the pressure continues to drop. The pump pressure detection element detects the pressure drop up to the activation point determined for the main electric fire pump and the main pump is activated. If there is no power in the system, the main electric pump cannot operate and the pressure continues to drop. When the pressure drop reaches the pressure drop value defined for the diesel pump, the diesel pump pressure detection element starts the diesel pump.
Jockey pump and Electric Main fire pump compress the system under pressure by working for a while more when the system pressure reaches the specified pump deactivation pressure when the water use in the fire protection system is terminated and it is deactivated. However, when the diesel pump starts to work in the system, when water consumption stops, it does not stop if there is no special definition. It is necessary to go to the pump room and manually deactivate the fire pump. The diesel pump continues to compress the system until your staff goes to the pump room. To protect the system from the overpressure created by the diesel pump, a pressure relief valve and a free flow subject at the outlet are used. When the pressure reaches the limit defined in the pressure relief valve, it releases the pressure by opening the line. Thus, the fire protection system is protected from overpressure.
Pressure detection element is placed inside the control panel, sensing the water pressure through the pipe connection, protected against water impacts, lower and upper values can be adjusted separately and independently and must be lockable after adjustment.
A minimum pressure difference of 1.5 – 2 bar is defined between the switch-on and switch-off pressures of the pumps.
Maintenance of Fire Pumps
Periodic annual maintenance of the fire pump group is mandatory. Maintenance and field performance testing of fire pumps must be repeated every year at specified intervals and records must be kept.
Supplying UL Listed and FM approved fire pump groups, which are the most important component of fire protection systems, to be assembled and put into use will be extremely effective in protecting your investment. AKSAY Yangın supplies UL Listed and FM approved pumps in the range of 100 – 7000GPM (378 – 26.474 l./min.) and installs them with its own personnel.
The production range is 100 – 5000 GPM (378 – 18925 lt./min.) and diesel and electric fire pumps are available. Pump groups in the specified range are UL listed and FM approved.
