BACKGROUND: It was reported that a few hospital patients on the 8th floor were feeling vibrations in the floor. These vibrations were actually making some of them feel sick. REDLINE was called in to identify the source of the vibration and eliminate it if possible.
FINDINGS: We were taken to the 8th floor where the vibrations had been noticed. Using Vibration Spectral Analysis, we were able to identify that the floor was vibrating at 614 cycles per minute (CPM).
FYI: We also collected vibration data on the 12th floor. This data showed a peak at the same exact 614 CPM frequency that we found on the 8th floor. It would appear that the vibration was indeed related and being transmitted throughout the building.
Now we just needed to find the source of this vibration.
After asking some questions we were told that the 9th floor had several running Air Handler Units (AHU). We went to the 9th floor where we preceded to collect and analyze data from each AHU, looking for the unwanted vibration frequency (614 CPM)
We were successful. We found an AHU with a fan running at 605 CPM. (This will most likely be the culprit.) The fan was also identified to be running outside of its balance specification.
SOLUTION: We balanced the fan down to below specification. This would bring the fan from 7.7 Mils of movement to .5 Mills.
The 8th floor was retested. The problem vibration had been eliminated and the patients had never felt better.
