Updated: Jan 21
Fire pumps are at the heart of fire fighting systems because they provide the necessary water that a fire fighting system requires. Due to the increased use of petroleum-based products, denser storage configurations (e.g. multiple-row racks), and higher storage-, a more significant percentage of industrial/commercial fire fighting systems are hydraulically more dense to control or even suppress a fire. In layman's terms- pipes are larger, fire fighting orifices (openings) are more extensive, etc. A water supply system must deliver higher volume and pressure to meet these fire fighting systems' hydraulic demands.
Many municipal water supplies were designed/installed decades ago when such high demand was not required. The water demand of the town/community has increased over the years, with supply systems not keeping up. Most "domestic" requirements also do not need high water pressures as fire fighting systems require, so municipal systems simply are not configured to provide the kind of pressures fire fighting systems require. There are also other reasons to keep water pressures in check- higher pressures need more significant preventative maintenance costs, safety concerns, etc. Of course, we're assuming there is a public water supply- there may not be one. There might be a water tank that the fire pump draws from, in which case there would be no water at all if the pump failed (at least with a municipal supply, there is some water provided to the fire fighting system, even if the pump fails).
A Fire Pump Maintenance Program is a necessary part of fire protection and safety. The fire pump is part of the fire fighting system water supply. It allows the water to flow at a higher pressure to ensure you can put out a fire quickly and efficiently.
If the pump doesn't correctly function during a fire, it could result in a significant financial loss due to damages. That's why it's so important to know how to maintain your fire pump. Our Fire Pump Maintenance Program will help you know exactly when you need to schedule tests and services to keep your pump in optimal condition.
Because of the reliance on an adequate water supply, fire pumps must be dependable. They must operate when called upon to do so. The fact is- many fire pumps fail to perform either adequately or even at all. This failure almost always is a result of inadequate or even non-existent preventative maintenance. Sometimes it's helpful to use a simple comparison. Most people who will read this blog have workplaces that they must commute to promptly. Imagine your regular vehicle is unavailable, and you must use another car that has been parked for months or even years without being started. Would that vehicle begin if it had not been run or maintained? It may or may not. This is the same with fire pumps. Fire pumps have water in the pipes. There is an internal impeller. Water has sand/muck/rust/stones and whatever else in it (yes- municipal water also does). Parts that are not "exercised" (run) freeze/slow for various reasons. Motors or diesel engines need maintenance; batteries need attention, etc. If we are to have confidence, a pump will start and operate as it was designed to.
Well, we could go on, but I think the point is made that without recommended preventative maintenance, there is a greater risk that the "heart" of the fire fighting system will not pump.
Basics on Fire Pumps
Let's take a minute to cover a few basic facts about fire pumps. They can be expected to produce 120-140% of rated pressure at zero flow (or churn, commonly known) conditions. The rated point of the pump yields 100% of its rated flow and pressure. The maximum flow expected from a fire pump is 150% of the rated flow at only 65% of rated pressure. These three points help define the characteristic fire pump curves for a particular fire pump.
What size of a fire pump is the right one? Well, there are probably as many answers to that question as there are letters in the alphabet. Still, most experts would say that a fire pump needs to be large enough to provide an adequate flow and pressure for the maximum flow expected from any single fire fighting or deluge system, plus an extra (hose) allowance for fire-fighting needs. For example, if maximum fire fighting demand is 1,000 GPM at 60 psi, and fire-fighting (hose) allowance is 500 GPM, then at least 1,500 GPM at 60 psi is needed from the combination of the fire pump and public or private water supply. Some insurers and Authorities Having Jurisdiction (AHJ) would prefer that the maximum demand point not exceed the rated threshold (100% of flow and pressure) of the fire pump. Others would accept something between the rated point and the maximum flow point, but few would go all the way to the latter point.
It is not uncommon to install one extra fire pump at huge sites so that, even if one pump fails or is out of service for repair, there will still be a more than adequate water supply for the site. An electric fire pump is considered reliable but depends on the ready availability of a reliable electric power supply. Diesel fire pumps are also reliable but have their own power supply (diesel fuel). A common and more reliable method is to have one electric and one diesel fire pump at some larger sites. There is no "one size fits all" answer when it comes to fire pumps.
Preventative maintenance. The following is a brief bullet summary of the inspection and preventive maintenance activities that should occur following the National Fire Protection Association (NFPA), detailed in their standard #25- Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems. This should not be confused with NFPA 20 Standard for the Installation of Stationary Pumps for Fire Protection, which does not cover preventative maintenance (some time ago, NFPA consolidated all preventative maintenance into NFPA 25). These points are only the critical inspection points - NFPA 25 should be consulted for a full inspection/testing requirements chart. It should also be noted that testing should be performed by a trained staff member and preventative maintenance by certified/licensed professionals. The control panels contain high voltage, so professionals with appropriate personal protective equipment (e.g. flash suits) should perform the work.
It should also be noted that before completing any testing of the fire pump, notify all parties who might respond to an alarm (central station, fire department, security personnel, etc.).
Fire pumps should be tested for automatic starting by either opening the test valve on the small brass piping from the fire pump piping to the power controller or flowing water from the primary drain test at a fire fighting riser inch drain inspector's test connection.
Electric motor pumps should be started weekly. The pump should be run through its preset timer for ten (10) minutes.
Internal combustion engines (almost always diesel) should also be started weekly. The pump should be run for thirty (30) minutes to bring the engine up to full speed, pressure, and temperature.
The following should be checked on all pump systems (electric & diesel)
Record system suction and discharge pressure gauge readings
Check pump packing glands for slight discharge
Adjust gland nuts if necessary
Check for unusual noise or vibration
Check packing boxes, bearings, or pump casing for overheating
Record pump starting pressure
Observe time for the motor to accelerate to full speed
Record time controller is on the first step (for reduced voltage or reduced current starting)
Record time pump runs after starting (for automatic stop controllers)
The following are specific checks for diesel pumps
Observe time for the engine to crank
Observe time for the engine to reach a running speed
Observe engine oil pressure gauge, speed indicator, water, and oil temperature indicators periodically while the engine is running
Record any abnormalities
Check heat exchanger for cooling water flow
Every year the pump should be tested at full operation. There is usually a "test header" pipe assembly with a pipe leading through the wall to an outside test header that has several valves to connect hoses to (I say "usually" because some systems use a bypass flow meter, which is allowed under certain conditions). The pump is operated at "churn" (zero flow), 100% of required capacity, and 150% of necessary capacity. Fire protection specialists who are competent/trained and have the correct equipment should perform this test. It is also critical that NFPA 70E Standard for Electrical Safety in the Workplace® be complied with (PPE, etc.).
This test is critical. It will show whether the pump performance is still adequate or deteriorated at all (in which case NFPA spells out how much deterioration is allowed before the pump must be overhauled).
Weekly inspections should be conducted
Pumphouse/room: Heat not less than 40°F or 70°F for pump room with diesel pumps without engine heaters
Ventilating louvres free to operate
Housekeeping- no combustible storage
Pump assembly inspection
Valves fully open (except for the test header)
Line pressure gauges
Controller "power on" light illuminated
Transfer switch normal light illuminated
Isolating switch closed - standby (emergency) source
Reverse phase alarm pilot light off (or normal phase rotation pilot light on)
Oil level in the vertical motor sight glass
Fuel tank two-thirds full
Controller selector switch in the AUTO position
Batteries (should be two operational batteries) Normal readings for voltage, charging, current, and failure lights off.
Battery terminals free from corrosion
All alarm lights off
Engine running time meter reading
Oil level in right angle gear drive normal
Crankcase oil level normal
Cooling water level normal
The electrolyte level in batteries normal
Water-jacket heater operating
Regular Testing Required
One thing for sure-fire pumps (all types and sizes) must be tested regularly, preferably by automatic start (most of the time), but also by manual start (occasionally). How often? Some say weekly no matter what, as in NFPA 20. Others say weekly for diesel fire pumps and monthly for electric fire pumps. These tests are a startup and run tests (with no water flow), similar to starting your car on a frigid winter morning. How long should these tests run? Again, everybody has different advice, but I say 30 minutes for diesel pumps (at rated speed and average operating temperature) and 10-15 minutes for electric fire pumps (again under normal running conditions). "NFPA 25, Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems" (1998 edition) contains a full range of recommended tests and frequencies in Chapter 5. All of the specifics are included in that document. NFPA 25 is adopted into state law in some areas and indeed a requirement in that case, but it gives excellent guidance in any case.
Are you looking for help solving your facility's fire protection system, fire fighting system, and fire safety issues? Installation, Service & Maintenance, Upgrading & Repair? Connecting with an experienced Fire Protection Consultant at PSB Fire Engineers can help. At PSB Fire Engineers, we understand that your unique building needs unique fire protection systems. Our team is equipped to ensure you receive the fire protection you need to keep your facility and people safe from harm.