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December 1, 2022

Precision Shaft Alignment and Vibration Testing of Fire Pumps

By Stan Riddle

Fire Pump 1

Fire pumps are probably THE MOST CRITICAL machines in industrial and commercial buildings.  If they don’t work when they are supposed to, no other machine in the building matters.

A fire pump needs to be reliable enough to run for a few hours.  After that, either the fire is out, or the building is gone.  But in many instances of fires in industrial or commercial buildings, the fire pump may need to function reliably for hours, or even days.

So why spend the effort toward precision maintenance practices, such as shaft alignment and vibration testing, on a machine that only runs a few hours per year?

So – when it has to run – it will!  Some insurance carriers recommend laser alignment and vibration testing of fire pumps and may offer discounted rates if this practice is performed.

From an operational standpoint, fire pumps are operated on a regular basis-weekly or monthly.  The pump typically only runs for 30 minutes or an hour.  Even then, they are run on minimum flow, or recirculated.  Most companies perform an annual flow test on fire pumps.  In this scenario, the fire pump runs at full capacity, pumping the maximum flow rate, to make sure the pump’s flow rate and pressure requirements are as stated.  From a vibration standpoint, this is when vibration measurements should be taken on the pump, to make sure the motor-pump combination is in good condition.

NFPA 20 and 25 recommend that the pump should be aligned according to both the manufacturer’s recommendations, and Hydraulic Institute specification, and that an annual alignment check (and corrections as needed) be performed annually.  It’s also a good time to perform a coupling inspection, and lubrication.

For more information, see https://acoem.us/blog/other-topics/fire-pump-maintenance/