Fire Pump

Fire Pump Types

There are many types of fire pumps available. It is important to select the correct type of pump for the installation project to avoid excessive costs, and to avoid excessive pressures that might damage your system. If all the factors are not taken into consideration it could result in a pump installation that does not achieve the necessary pressure requirements which could require a new pump tobe installed.There are two main categories of pumps: positive displacement and centrifugal. Positive displacement pumps are characterized by a method of producing flow by capturing a specific volume of water per pump revolution and pushing it out through the discharge line. A bicycle tire pump is an example of a positive displacement pump we commonly see. Positive displacement pumps create very high pressures but have limited flow volume compared with centrifugal pumps. These are not as common because they have a specialized use, primarily with water mist and foam-water systems. Centrifugal pumps are the most common fire pumps and are used with most systems. With centrifugal pumps, pressure is developed principally by the action of centrifugal force or spinning. Water in centrifugal pumps enters the suction inlet and passes to the center of the impeller. The rotation of the impeller, in turn, drives the water by centrifugal force to the rim where it discharges. Centrifugal pumps can handle large volumes of water while providing high pressure boosts. With a horizontal split-case pump, the flow is split and enters the impeller from opposite sides of the pump housing. As the name implies, this is a pump installed with a split casing that can be opened for pump maintenance access and is connected to the driver by a horizontal shaft. They are very reliable, come in a wide range of rated flow and pressure capacities, are easy to maintain due to their relatively easy split-case access, and can be used with both electric and diesel drivers. However, these also typically need the most space of all types of fire pumps. These pumps can be used with raw water sources such as ponds, lakes, and rivers. Vertical turbine pumps come in a wide range of capacities and pressures, and they can be used with diesel and electric drivers. In-line pumps are useful where space is limited. These can be driven by both a vertical or horizontal shaft (end suction type). Vertical shaft types, which are the most common, have the driver located directly above the pump. These are typically one of the less expensive units and take the least amount of space but, they are also one of the more expensive to repair. Pump maintenance and repair can be difficult because the motor must be lifted off and removed to gain access to the pump, unlike a split-case unit. With these pumps, the suction flange and discharge flange are on approximately the same plane. In-line pumps have a limited capacity of typically no more than 1,500 gpm (5,678 L/min), and they can only be used with an electric driver which limits their potential applications.

Fire pumps are an essential part of most fire protection systems, as they allow for taller buildings, smaller piping and higher pressure and flow rates in systems. Incorrectly sized or selected pumps can result in not enough pressure or flow being created, which can cause several problems. Spray patterns from sprinklers don’t develop properly. Not give enough pressure to hose valves at the top of a high-rise building. Too much pressure, causing components to burst and break open during use. While electric and diesel-powered fire pumps deliver essentially the same results, their engines operate differently and require different protocols for maintenance and testing. Electric motor-powered engines are a cheaper option and are slightly more common. They require less maintenance and inspections, which is another perk. However, if there is no backup generator, the pump is rendered useless if the power goes out, which is a serious disadvantage and will likely also mean the fire sprinkler system itself is of no use. The sprinkler system design will determine whether or not a fire pump is required. Once a sprinkler system is designed and installed, it receives a water-flow test. If that test demonstrates insufficient gallons per minute (flow) or water pressure to meet the sprinkler system demand, the designers must include a fire pump in the application. The fire pump provides the additional PSI and/or gallons per minute necessary to ensure the sprinkler system can operate effectively. The cause for the insufficient water pressure or flow varies, but it often has something to do with a low water pressure supply from the water’s source, whether it be the local public utility or a nearby pond engineered for supplying water to the fire safety system. In theory, then, a sprinkler system may not require a fire pump in one location, but a sprinkler system of similar size and complexity may require a fire pump at a different location.

Fire Pump Inspection and Testing Requirements

All pump houses and fire pumps require weekly visual inspections to check on the pressure, suction, and discharge, and to ensure that all the valves are in the open position, the fire pump controller is in a normal state, etc. Both electric and diesel-powered pumps must also be no-flow or dry tested. This must be done weekly for diesel-powered pumps, while electric-powered pumps usually require dry-testing only once every month for ten minutes. However, certain electric applications do require weekly dry tests as well. Both the weekly visuals and the weekly/visual dry tests can technically be performed. By the property’s regular maintenance personnel, as long as they have been trained on what to look for and how to perform the tests. However, many customers still elect to have come out to perform these inspections and tests, as it decreases their liability. Finally, fire pumps must also undergo full annual testing that puts the whole system through its paces, using actual water, and this testing must be performed by a licensed professional. During the tests, the technician will measure water pressure and water flow and then compare the measurements to the fire pump’s original design specifications to ensure it’s operating effectively. When discrepancies are found, there is often an easy explanation and repair that can be made to correct the problem, such as when a clog is discovered or a simple piece of hardware needs to be replaced. Diesel-powered fire pumps must be serviced annually in addition to the inspections and tests. This maintenance includes changing fuel filters, testing batteries, fluid levels, oil filters, etc. Maintenance must be performed by someone certified to work on diesel engines for fire pump application, not just a regular technician.

What Makes a Fire Pump Different from Other Kinds of Pumps?

Choosing the ideal fire pump for your facility is a complex process as it depends on many factors, such as capacity, cost, system layout, and environmental considerations. While having a knowledge base can differentiate a passive building owner from a savvy one, tackling this critical fire and life safety challenge alone is never advisable. Are you also amongst the ones who don’t find any difference between fire pumps and other pumps, primarily domestic water pumps? Both pump water, don’t they? But they are as different as the scenarios they are employed in. And as the material and construction of fire pumps is different, they are far more costly than ordinary pumps. As we mentioned, both pumps are used in different situations wherein the fire pump is an emergency pump, rarely used in normal times. But all the time it is not in use, the fire pump still needs to be intact for whenever it is needed. So, a fire pump is constructed, keeping in mind to keep its corrosion resistance factor high- much more than that of an ordinary water pump. Like, water pumps have a cast iron material used in the construction of their impeller, compared to the pure copper or stainless steel impeller of fire pumps. No matter how similar their applications might look, it is important for a fire pump to be fire resistant- something a water pump doesn’t need. A fire pump is not merely supplying water, it is used douse fires so, the material of the pump has to be metal and the surface of fire pump needs to a red paint coating, which not only stops it from getting rust but also fire-proofs it. Fire pumps have to be high-temperature resistant as they may have to counter scorching heat in the event of a fire hazard, something ordinary pumps don’t have.