At the end of this article, you’ll find a list of discussion questions to help facilitate crew conversations on the topic.
By Bruce Moore
There has been an increase in the building of larger commercial, warehouse and industrial buildings. These buildings will have automatic sprinkler systems and, often, industrial fire pumps. But how much do we understand about industrial fire pump operations? Unfortunately, the answer is usually very little. This lack of knowledge makes it exceedingly difficult to use these pumps to our advantage.
On-site industrial fire pump systems
We are typically taught that if we arrive at a scene of a fire in a sprinklered facility, we are to connect to the Fire Department Connection (FDC) and pump water into the sprinkler system to ensure that we have adequate pressure and water to maintain the sprinkler system. But, what about buildings equipped with on-site industrial fire pumps? Should we automatically start pumping water into the FDC? How can we incorporate these onsite fire pumps in our operations?
Fire protection systems at large facilities have a fire loop. The fire loop is an underground water main system that surrounds the building on all sides and, through a series of valves, supplies water to the sprinkler systems and yard hydrants. The pressure of the fire loop is maintained by the on-site industrial fire pumps. When the system pressure drops below a certain point, the on-site pumps will engage in order to reset the system pressure.
In facilities with an industrial fire pump system, there will be a jockey pump and fire pump(s). Typically, industrial fire pumps range in size from 1,000 gpm to 3,500 gpm. In larger facilities, there may be more than one fire pump. While the fire loop is designed as a closed, pressure-stable system, there will be leaks that result in the system pressure dropping. When the pressure drops below a certain point, the jockey pump will turn on to build the pressure back up to a normal level, and then turn itself off. If the jockey pump cannot bring the system back to its normal pressure – like during a fire situation – and the pressure continues to drop, a fire pump will turn on. Once an industrial fire pump is running, it will not automatically shut itself off; it must be manually turned off.
An industrial fire pump system is all about pressure. When the system pressure drops, jockey and fire pumps turn on. Commonly, the pressure difference between the pumps is in 10-psi increments. For example, if the normal system pressure is 150 psi, and the pressure drops to 140 psi, the jockey pump will turn on to build the pressure back up to 150 psi and then turn itself off. However, if the pressure continues to drop and reaches 130, the first fire pump will turn on. If the pressure continues to drop to 120 psi, the second fire pump will turn on, and so on. These fire pumps will continue to run until they are manually shut off.
In buildings equipped with fire pumps, the fire pump is designed to have a continuous water supply to the pump(s) as long as they are running. The supply could be from an above-ground storage tank that refills as the level falls or from a municipal water supply or both. Regardless, when you arrive on the scene, note that there is already a fire pump, designed with a continuous water supply, supplying pressure and water to the activated sprinkler system(s).
Firefighter next steps and instructions for use
So, when the fire department arrives on the scene of a large facility and the fire pumps are running, what do you do? We first need to determine where the fire is located and whether the sprinkler system is keeping the fire in check. Most commercial/industrial sprinkler systems are not designed to extinguish the fire; they are merely designed to control the fire until the fire department arrives.
While we are checking the fire location and severity, we need to connect to the fire department connection (FDC), but not charge the lines. Next, someone should be sent to the pump house/room to determine if the fire pump is running or if it needs to be turned on. Then, before supplying the FDC, we need to determine the pressure reading on the fire protection system.
To check the system’s pressure, you can look at the reading of the bottom gauge of a sprinkler riser. The bottom gauge shows the fire loop/fire protection system pressure, and the upper gauge tells you the pressure of that riser’s sprinkler system. The bottom gauge of every riser will show the same fire protection system’s pressure reading. However, at the riser supplying the sprinkler system that has activated, the upper sprinkler system pressure gauge will be less than the non-affected risers. You can also check the system pressure by looking at the discharge pressure gauge on the fire pump.
If the pressure in the fire protection system is in the range of the pressure we would be supplying or close to the facility’s normal operating pressure, then we do not need to charge the lines to the FDC. We just need to monitor the fire suppression system and its pressure, advance hoselines and conduct final extinguishment.
In a fire, the shutting off of riser(s) supplying a sprinkler system and the shutting down of the fire pump should usually occur when the fire is completely extinguished and we have determined that there is no fire spread. Visibility will be limited due to the sprinkler system keeping smoke at a lower level and the steam being produced by the discharged water. However, we should not turn off the riser to the affected sprinkler system or the fire pump just to improve visibility. Prematurely shutting off the riser and turning off the fire pumps can cause a fire to spread and consume more of the building.
Each industrial fire pump will have a controller. The controllers have an automatic and manual start, with start buttons, plus test and off mode settings. The controllers are normally in auto mode. To stop a pump from running, either move the selector switch to the off position or press the off button, depending on the type of controller. When operations are complete, the affected sprinkler system has been isolated or restored, and the system pressure has returned to normal, the fire pumps should be returned to the auto mode.
Maximizing pump systems
Industrial fire pumps are like having fire engines already pumping on the scene. For example, in a large facility with three 2,000-2,500-gpm pumps, the combined flow rating (6,000-7,500 gpm) is higher than a fire department can provide. Additionally, these new buildings with industrial fire pump systems already have their own water supply. Why wouldn’t we take advantage of that?
Discussion questions
- What are the key differences in responding to a fire in a building equipped with an industrial fire pump system compared to a building without one?
- How would you determine if the fire sprinkler system is effectively controlling the fire, and what steps would you take if it is not?
- What are some potential challenges or dangers of prematurely charging the lines to the Fire Department Connection (FDC) or shutting off the fire pump and risers supplying a sprinkler system?
- When and how should the pressure reading on the fire protection system be checked during a fire situation in a building with an industrial fire pump system?
- How can firefighters better utilize the capabilities of the industrial fire pump systems to effectively control and extinguish the fire?
About the author
Bruce Moore is an adjunct fire science instructor and fire science program developer for Columbus State Community College in Ohio and an adjunct fire science instructor for Purdue University Global. He previously served as fire chief for the Sturgis (Michigan) Fire Department, the Worthington/Sharon Township Division of Fire and EMS in Ohio, and the Oshtemo Fire Department in Michigan. He also served as an industrial fire chief for Securitas Security Corporation.