fire pump preventative maintenance

05/09/2018

The Challenge

Fire pumps are at the heart of fire sprinkler systems because they provide the necessary water that a sprinkler system requires. Due to the increased use of petroleum-based products (i.e. plastics/polymers), denser storage configurations (e.g. multiple-row racks), and higher storage-, a greater percentage of industrial/commercial sprinkler systems are hydraulically more dense in order to control or even suppress a fire. In layman’s terms- pipes are larger, sprinkler orifices (openings) are larger, etc., and a water supply system must deliver higher volume and pressure to meet the hydraulic demands of these sprinkler systems.

Many municipal water supplies were designed/installed decades ago when such high demand was not required, and 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 sprinkler systems require, so municipal systems simply are not configured to provide the kind of pressures sprinkler systems require. There are also other reasons to keep water pressures in check- higher pressures require greater preventative maintenance costs, there are safety concerns, etc. Of course we’re assuming there is a public water supply- there may not be one. There may 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 sprinkler system, even if the pump fails).

The Problem

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 operate either adequately or even at all. This failure almost always is a result of poor 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 in a timely manner. Imagine your regular vehicle is unavailable, and you must use another vehicle that has been parked for months or even years without being started. Would that vehicle start 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 does also). 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 that 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 sprinkler system will not pump.

The Solution

Preventative maintenance. The following is a brief bullet summary of the inspection and preventative maintenance activities that should take place in accordance with the National Fire Protection Association (NFPA), which is 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/major inspection/testing points - NFPA 25 should be consulted for a full chart of inspection/testing requirements. It should also be noted that testing should be performed by a trained staff member, and the 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 whom might respond to an alarm (central station, fire department, security personnel, etc.).

Testing

  • All fire pumps should be tested for automatic starting by either opening the test valve on the small brass piping coming from the fire pump piping to the power controller (usually labeled) or flowing water from main drain test at a sprinkler riser inch drain or at the inspector's test connection to start the pump.
  • Electric motor pumps should be started on a weekly basis. The pump should be run through its preset timer for ten (10) minutes.
  • Internal combustion engines (almost always diesel) should also be started on a weekly basis. The pump should be run 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 motor to accelerate to full speed
  • Record time controller is on 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 engine to crank
  • Observe time for engine to reach running speed
  • Observe engine oil pressure gauge, speed indicator, water, and oil temperature indicators periodically while engine is running
  • Record any abnormalities
  • Check heat exchanger for cooling water flow

Annual Testing

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 required capacity.  Fire protection specialists whom 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 as it will show whether the pump performance is still adequate or whether it has deteriorated at all (in which case NFPA spells out how much deterioration is allowed before the pump must be overhauled).

Inspections

Weekly inspections should be conducted of the following:

  • Pump house/room: Heat not less than 40°F or 70°F for pump room with diesel pumps without engine heaters
  • Ventilating louvers free to operate
  • Housekeeping- no combustible storage

Pump assembly inspection

  • Valves fully open (except for the test header)
  • Piping leaks
  • Line pressure gauges
  • Suction reservoir

 Control Panel

  • 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 vertical motor sight glass

 

Diesel Engine

  • Fuel tank two-thirds full
  • Controller selector switch in 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
  • Electrolyte level in batteries normal
  • Water-jacket heater operating

Conclusion

It is difficult to condense the full inspection & testing requirements of fire pumps into a blog, so the intention here was to provide a starting point and more importantly an understanding that if your building sprinkler system has a fire pump as part of the system- it requires preventative maintenance just like your vehicle does!