A fire pump is any type of purpose-driven pump used within a fire protection system. It can be driven by diesel engines, electric motors or even steam and is used to provide increases in water pressure to meet the design requirements of a fire protection system. Fire pumps do not create a water supply. Instead, they create pressure from an existing water supply, such as a city supply line or a storage tank, by converting mechanical energy into hydraulic energy.Fire Pump Set
Fire pumps are necessary when the water supply available does not generate the necessary hydraulic pressure required to meet demand of a fire protection system such as automatic sprinklers and standpipes, or even foam systems. An example would be a high-rise building where the pressure from a city supply line is not great enough to overcome gravity to reach the top of the building. In this instance, installing a fire pump is done to provide a boost to get the necessary pressure to the top. It is important to remember to have a steady supply Fire Pump Set of water so that the fire pump may operate correctly.
When it comes to best practices for fire pump design and installation, the National Fire Protection Association 20 Standard for the Installation of Stationary Pumps for Fire Protection provides the guidebook.20 provides guidance for fire pumps and their installations but does not provide listings and defers to the authority having jurisdiction as the entity with the final say on installations. The HAJ could be the local fire chief or it could be the insurer—it depends on locale.
With regard to listings, groups such as Underwriters Laboratories (UL) and Factory Mutual (FM) provide UL Listings and FM Approvals on products that meet their testing requirements along with their own individual publication standards, UL448 and FM1311. NAPA 20 does not provide listings or approvals but acts as the guide for best practice. If a fire pump has the UL and FM stamp of approval, the manufacturer has gone through the most stringent requirements to be able to provide their pumps for fire protection, giving peace of mind that the pump will operate when it is needed.
NFPA 20, UL and FM provide guidance on the basic requirements fire pumps must meet to be considered as such. Each fire pump must be tested and meet the following requirements before it can be shipped, with a certified factory test curve being provided.
The first requirement is to have a rated duty point, which consists of the rated flow (gallons per minute and the rated pressure (pounds per square inch [psi]). Second, the fire pump must be able to meet 150% of the rated duty mpg while maintaining at least 65% of the rated duty point pressure. Third, the dead head, or churn pressure (pressure at no flow), must not be more than 140% of the rated duty point pressure. It should be noted that FM also requires a constant rise to shut off, which means the pump pressure must always be increasing as pump flow is reduced.
Finally, the driver of the fire pump, whether it is an electric motor, diesel engine or steam turbine, must be sized to meet the full horsepower demands of the fire pump, even if it means flowing beyond the 150% required duty point. The best way to ensure that the driver is sized correctly, and conforms to UL and FM requirements, is to review the certified factory test curve.Fire Pump Set
Look at the horsepower curve on the factory-certified test report and ensure that the power curve peaks and then begins to fall. This peak represents the highest amount of power the pump requires and the driver must be sized to meet that requirement. If the power curve is continuing to rise, the pump has not been tested to the full requirements of UL and FM, and the motor could be undersized and in violation of UL and FM.
An example of these requirements would be a fire pump UL Listed and FM Approved for 1,000 gpm at 100 psi, using an electric motor. The 150 psi at 65% point would be required to flow at 1,500 gpm while maintaining a minimum pressure of at least 65 psi. The 140% churn pressure must be less than 140 psi at 0 gpm. The pump curve (Image 1) shows a constant rise to shut off from the rated point to churn. The horsepower curve shows a peak of 86 brake horsepower (BHP) at 1,600 gpm, signaling that pump power peaks at 160% and requires a 75-hp electric motor. Many UL fire pump motors allow for a 1.15 service factor, so for this instance, a 75-hp motor provides Fire Pump Set
Overall design and operation of fire pump installations have not changed much in the past few decades, save for some innovation on controls and other incremental improvements. However, recent developments in the industrial internet of things (IIoT) space have led to offerings that are changing the information users can glean from the fire pump and the entire fire protection system, leading to safer, more informed systems.
Up until recently, users only knew if the fire pump was on from a remote alarm but had no idea what it was actually doing. Was it flowing water or running at dead head? Was overall flow increasing over time in a fire event or had it plateaued, signaling the fire had been contained? How often was the pressure maintenance (jockey) pump running, and was there a potential leak in the system? What is the pump room temperature and is the system at risk of freezing?
Recent weather events in Texas caused many systems to freeze and break, leading to costly replacements—temperature monitoring and alerts could have helped with early action and prevention
ire pumps are used to increase the pressure of water sourced from a municipal underground water supply piping network, or a static supply (e.g., tank, reservoir, lake). A fire pump is a centrifugal- or positive displacement- pump that has been tested and listed by a third-party testing and listing agency, such as UL or FM Global specifically for fire service use. The main standard that governs fire pump fixed-place installations in North America is the National Fire Protection Association’s NFPA 20 Standard for the Installation of Stationary Fire Pumps for Fire Protection.Fire Pump Set
Fire pumps are powered most commonly by an electric motor or a diesel engine, or, occasionally a steam turbine. If the governing model building code requires backup power independent of the local electric power grid, a fire pump using an electric motor may utilize an emergency generator when connected via a listed transfer switch. Fire pumps installed on fire trucks and boats are powered by the engine of the vehicle/vessel.
Utilizing a control panel with pressure sensors, fire pumps automatically start when the pressure in the fire sprinkler system drops below a per-designated threshold. Given the incomprehensibility of water, fire suppression system pressures drops significantly and quickly when one or more outlets open. Examples would be fused (opened) fire sprinklers, fire hose valves connected to a standpipe, or automatic control valves opened by release panels.
Fire pumps are utilized when determined by hydraulic calculations that the existing water supply cannot provide sufficient pressure to meet the hydraulic design requirements of the suppression system. This usually occurs if the building is very tall, such as in high-rise buildings (to overcome hydraulic head losses created from elevation differences), in systems that require a relatively high terminal pressure at the fire suppression outlets (to provide sufficient water droplet penetration of a fire plume), or in systems that require a large discharge of water (such as storage warehouses). Fire pumps are also needed if fire protection water supply is provided from a static source which provides little or no pressure. Some situations may be compounded by all of these factors, requiring large water supplies and powerful fire pumps.
Common types of fire pumps used for fire service include: horizontal split case, vertical split case, vertical inline, vertical turbine, and end suction.
jockey pump, also known as a pressure-maintenance pump, is a small pump connected to a fire suppression system near the fire pump and is intended to maintain pressure in a fire protection piping system. These pumps recover pressures lost from gradual, slow pressure declines in a system due to temperature changes, trapped air escapement, or very small leaks. The jockey pump is essentially a portion of the fire pump’s control system. A jockey pump is sized for a flow less than one sprinkler in order to ensure a system pressure drop significant enough to start the main fire pump. Jockey pumps are typically small multistage centrifugal pumps, and do not have to be listed or certified for fire system application. The control equipment for jockey pumps may however carry approvals. Jockey pumps should be sized for 3% of the flow of the main fire pump and to provide 10psi more pressure than the main fire pump (As per Code IS 15105 : 2002)
In India, the pump manufacturers generally adhere to the TAC (Tariff Advisory Committee) guidelines, although pump manufacturers also obtain listings with UL or FM Global. For the purpose of installation & maintenance of fire-fighting pumps, Bureau of Indian Standards has published IS 15301 which is being followed throughout India.
How Does a Fire Pump Work?
A fire pump is an integral part of a fire sprinkler system, as it provides high-pressure water accessibility to the fire sprinkler system, increasing the flow rate of the water.
To understand how a fire pump works, it’s important to understand what a fire pump is. A fire pump is more than just it’s namesake – a pump – which is an integral part of the system, but the full system is made up of the motor – or driver – and the controller. As part of a fire sprinkler system, a fire pump receives water from either an underground water supply or a water tank, lake, or reservoir, and is powered by electricity or diesel fuel. The high-pressure supplied by the pump distributes water through the sprinkler system and hose standpipes.
Customary types of fire pumps include the horizontal split case, vertical split case, vertical in-line, and vertical turbine.
The most common type of fire pump is the horizontal split case. These pumps are most economical for higher flow applications and are easily accessible for repairs or maintenance. Their long lifespans and size availability make them even more popular.
The vertical in-line pump is a single-stage centrifugal pump designed, as the name implies, for vertical installation. With suction and delivery inline with each other, this pump provides a smooth flow of water throughout the system, and is ideal for small spaces. The design does require the pump to be removed for any repairs or maintenance.
The vertical turbine is a centrifugal pump designed for fire pump services where the water source is located below ground. This fire pump comes in varying types such as oil-lubricated enclosed-line-shaft and water-lubricated open-line-shaft pumps. Both types are designed for installation in drilled wells, lakes, streams, open swamps, and other subsurface sources.
Deciding which pump is appropriate for any given facility should be discussed with the design engineer, a fire safety professional, and the Local Authority Having Jurisdiction (AHJ).
Installing and Maintaining Fire Pumps
As with the decision on what pump and system to use, the installation and maintenance of any fire system should be handled by fire safety professionals. There are many considerations as per the National Fire Protection Association (NFPA) and the International Building Code (IBC), which are updated from time to time.
Though weekly inspections may be done by trained personnel on-site, monthly, annual, and further inspections and maintenance should be performed by qualified personnel including factory-trained and certified personnel, personnel certified by a national recognized fire protection organization, or personnel who are registered, licensed, or certified by a state or local authority.
Fire Pumps in Your Building
A fire pump is critical fire and life-safety equipment in many buildings. There are numerous requirements and elements to be considered prior to the installation of any unit. The building owner, architect, engineer, local fire marshal, and the fire protection provider should all participate in the discussion for the pump and system to ensure a well-planned and compliant final installation.