The Human Factor in Equipment Failures

Executive summary

Outside factors can defeat any system. That’s why pre-planning and an appropriate response by operations personnel are important. In one case, serious damage resulted in the fire suppression system of a 27-story office building. The system consisted of a 2 hp jockey pump, 1,000 gallon per minute engine-driven fire pump, and the associated sprinkler piping, alarms and electrical controls.
The fire pump was controlled by a pressure switch during normal operation. As the pressure in the fire protection system decreased, the jockey pump restored the system pressure to normal parameters. If the pressure continued to drop (signifying the possible actuation of the sprinkler system) the fire pump automatically actuated to deliver water to the building’s sprinkler system.

The full article

The Human Factor in Equipment Failures

Warning Light

On the evening of the incident, the night security guard noticed a red light on his display panel, indicating the fire pump had activated. There was no sign that the fire/smoke detectors were set off. The guard confirmed the pump was actually running and that there was no fire. He then contacted maintenance personnel, who secured the pump about an hour later.

Damaged Equipment

The fire pump controls were fully operational. The jockey pump motor had burnt windings and would no longer operate. The fire pump was still operational; however, the pump’s housing was distorted and leaking profusely. Subsequent pump flow tests indicated the pump would still provide the rated no-load pressure, but was severely deficient at full flow.

Lessons Learned

Investigation revealed the city had secured the water main to the system for about six hours to perform repairs outside the building. The building’s occupants were not notified as agreed upon. As normal pressure decrease had occurred in the building’s fire protection system, the jockey pump had actuated. Since there was no water available to re-pressurize the system, the fire pump eventually actuated as intended and ran under a negative suction head until secured by maintenance personnel.
Maintenance personnel took too long to respond. Furthermore, upon arrival in the fire pump room, they should have immediately recognized the signs of cavitation which are indicated by irregular noise and no pressure reading on the suction gage. Upon finding the lack of water supply, maintenance personnel should have notified the building’s management. The city should have notified the building’s management earlier that the water supply was impaired.
Effective communication is essential between utility personnel, facility management and maintenance personnel. Had a fire occurred during the six hours, lives could have been endangered and the building could have been extensively damaged or destroyed.
Disclaimer statement:

All recommendations are general guidelines and are not intended to be exhaustive or complete, nor are they designed to replace information or instructions from the manufacturer of your equipment. Contact your equipment service representative or manufacturer with specific questions.

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